Linsangs(Prionodon Horsfield,1822)are small,arboreal feliform carnivorans that live in the tropical and subtropical forests of Southeast Asia and southern China.Several lines of morphological evidence from the soft ti...Linsangs(Prionodon Horsfield,1822)are small,arboreal feliform carnivorans that live in the tropical and subtropical forests of Southeast Asia and southern China.Several lines of morphological evidence from the soft tissues,dentition,and basicranium support their placement in either Prionodontinae or Viverrinae of Viverridae.However,molecular evidence has not only excluded the linsangs from Viverridae but also established that they constitute a monogeneric family Prionodontidae sister to Felidae.For that reason,the examination of the skull osteology of linsangs and related taxa is necessary to better understand how morphological and molecular data-particularly morphology-have contributed to the reconstruction of the Feliformia phylogeny.During the summer field season in July of 2020,we stumbled across the carcass of a spotted linsang(P.pardicolor)in a karst cave on the outskirts of Chongzuo City.To contribute to the knowledge about the morphology of this enigmatic feliform carnivoran,we present a preliminary description of the exterior skull osteology of P.pardicolor.The craniodental morphology provides strong evidence for a closer phylogenetic relationship between P.pardicolor and Viverrinae.However,since both morphological and molecular approaches have inherent limitations,caution is urged when inferring feliform phylogeny based on either discipline alone.展开更多
Eospalax,one of the only two extant genera within the Myospalacinae,has a high species richness.Each species is distinguished by unique cranial and dental morphologies,as well as variations in temporal and spatial dis...Eospalax,one of the only two extant genera within the Myospalacinae,has a high species richness.Each species is distinguished by unique cranial and dental morphologies,as well as variations in temporal and spatial distribution.Consequently,Eospalax serves as a reliable indicator for the biochronologic and paleoenvironmental studies of the Quaternary of East Asia.A recent discovery of a complete fossil skull in a conglomerate deposit,a part of the Lower Pleistocene Sanmen Formation,near Jianyucha Town,Zichang County,northern Shaanxi Province,has been subjected to a detailed analysis.The specimens were identified as Eospalax simplicidens,an extinct species of Eospalax,based on dental morphology.The recent discovery of E.simplicidens in Jianyucha offers significant insights into the species’cranial morphology and contributes to a more comprehensive understanding of its geographical distribution.The distinctive feature of the posterodorsal location of the external acoustic meatus indicates either a plesiomorphy or an evolutionary convergence among E.simplicidens,African root rats(Tachyoryctes),and bamboo rats(Rhizomyini).A skull(IVPP V5398.1)and four upper jaws(V5398.2)from Gongwangling in Lantian,Shaanxi,previously identified as Myospalax fontanieri,is transferred to the species E.lingtaiensis.A skull(IVPP RV35055)from Jingou,Xin’an,Henan,previously identified as E.simplicidens,is transferred to the species E.youngianus.In this study,body mass estimates are made for extinct Eospalax.Both E.lingtaiensis and E.simplicidens are small-sized zokors,with an estimated body mass of less than or approximately 300 g,respectively.展开更多
To maintain soil quality under long-term saline water irrigation,the influence of manure on soil physical properties was examined.Long-term saline irrigation has been conducted from 2015 to 2024 at the Nanpi Eco-Agric...To maintain soil quality under long-term saline water irrigation,the influence of manure on soil physical properties was examined.Long-term saline irrigation has been conducted from 2015 to 2024 at the Nanpi Eco-Agricultural Experimental Station of Chinese Academy Sciences in the Low Plain of the North China Plain,comprising four irrigation treatments:irrigation once at the jointing stage for winter wheat with irrigation water containing salt at fresh water,3,4 and 5 g·L^(–1),and maize irrigation at sowing using fresh water.Manure application was conducted under all irrigation treatments,with treatments without manure application used as controls.The results showed that under long-term irrigation with saline water,the application of manure increased the soil organic matter content,exchangeable potassium,available phosphorus,and total nitrogen content in the 0–20 cm soil layer by 46.8%,117.0%,75.7%,and 45.5%,respectively,compared to treatments without manure application.The application of manure reduced soil bulk density.It also increased the proportion of water-stable aggregates and the abundance of bacteria,fungi,and actinomycetes in the tillage soil layer compared to the controls.Because of the salt contained in the manure,the application of manure had dual effects on soil salt content.During the winter wheat season,manure application increased soil salt content.The salt content was significantly reduced during the summer maize season,owing to the strong salt-leaching effects under manure application,resulting in a smaller difference in salt content between the manure and non-manure treatments.During the summer rainfall season,improvements in soil structure under manure application increased the soil desalination rate for the 1 m top soil layer.The desalination rate for 0–40 cm and 40–100 cm was averagely by 39.1%and 18.9%higher,respectively,under manure application as compared with that under the nomanure treatments.The yield of winter wheat under manure application was 0.12%lower than that of the control,owing to the higher salt content during the winter wheat season.In contrast,the yield of summer maize improved by 3.9%under manure application,owing to the increased soil nutrient content and effective salt leaching.The results of this study indicated that manure application helped maintain the soil physical structure,which is important for the long-term use of saline water.In practice,using manure with a low salt content is suggested to reduce the adverse effects of saline water irrigation on soil properties and achieve sustainable saline water use.展开更多
Antilospira is a small to medium-sized antelope with heteronymously spiraled horn cores.It was widely distributed in northern China from the Late Pliocene to the Early Pleistocene.It is a typical fossil bovid with imp...Antilospira is a small to medium-sized antelope with heteronymously spiraled horn cores.It was widely distributed in northern China from the Late Pliocene to the Early Pleistocene.It is a typical fossil bovid with important implications for biostratigraphy and antilopin evolution in China.Antilospira robusta is a species with highly fragmentary materials and has previously only been briefly discussed.Here we report on a new frontal with horn cores from the Early Pleistocene Wucheng Loess in Nalesi Township,Dongxiang Autonomous County,Linxia Basin,Gansu Province.This new material features heteronymously spiraled horn cores,deep longitudinal grooves,a sharp anterior carena on the horn core,and a large body size,which are characteristics similar to those of A.robusta.However,the horn base of the new material is more compressed than all the previously discovered spiral-horned antelopes,so we attributed it to Antilospira cf.A.robusta.This is the first time Antilospira has been found in northwestern China,and this discovery provides more morphological data for the classification of this group.CT scans of the horn core reveal the well-remodeled horn core trabeculae in Antilospira,which is different from what is observed in Spirocerus.The frontal sinuses are moderately developed in the Linxia specimen,extending backwards to the orbit but not to the horn base.The virtual reconstruction of the endocranial cast indicated that Antilospira has bending and narrow frontal lobes,wide temporal lobes,and relatively complex sulci on the cerebral hemisphere,which differ from extant Antilopini bovids in China.展开更多
Propylene oxide(PO)is an important petrochemical materials used to produce downstream products such as propylene glycol(PG),polyether polyols,and dipropylene glycol(DPG).Among these,DPG is commonly used as a solvent f...Propylene oxide(PO)is an important petrochemical materials used to produce downstream products such as propylene glycol(PG),polyether polyols,and dipropylene glycol(DPG).Among these,DPG is commonly used as a solvent for fragrances,cosmetics,food additives,and detergents,and can also be served as a moisturizer in cosmetics,showing broad application prospects.The distribution of DPG isomers in the products synthesized from PO and PG has a significant impactΔrGΔrHΔfHθΔfGθPO+PG⇌DPG PO+DPG⇌TPG PG+PG⇌DPG+H_(2)O PG+DPG⇌TPG+H_(2)O on the quality of the products.Therefore,conducting thermodynamic calculation on the reaction of PO and PG to synthesize DPG can provide a theoretical basis for practical operations and product distribution regulation.So,in this paper,the thermodynamic parameters of PO,1,2-PG,H_(2)O,tripropylene glycol(TPG)and three isomers of DPG under different reaction conditions is calculated.Additionally,the,and lnK for four potential reactions at various reaction temperatures and pressures are calculated.By designing isodesmic reactions and combining the results of thermodynamic calculations,the and for the isomers of DPG are obtained,and the relative error is less than 7%.The results show that in the process of preparing DPG by PO and PG,when PO∶PG=1,the reaction temperature ranges from 298.15 to 413.15 K,and the pressure ranges from 101.325 to 506.625 kPa,the reactions of and are thermodynamically spontaneous.While the reactions of and are thermodynamically unspontaneous.The optimal reaction temperature and pressure are 413.15 K and 101.325 kPa.The thermodynamic stability of the three isomers is DPG1>DPG2>DPG3 under standard conditions.The accuracy of the computational results is verified through experimental design,and based on this,the factors affecting product distribution are analyzed.展开更多
Commercial phosphor-converted white LEDs(pc-WLEDs)face two inherent limitations,namely blue light hazard and low color rendering index,due to the use of blue LEDs as excitation source.To address these challenges,viole...Commercial phosphor-converted white LEDs(pc-WLEDs)face two inherent limitations,namely blue light hazard and low color rendering index,due to the use of blue LEDs as excitation source.To address these challenges,violet LEDs are proposed as an alternative solution.Currently,phosphors that can be efficiently excited by violet light(with wavelengths from 400 to 420 nm)remain under development still.In this study,we utilize large language models to construct a comprehensive database of Eu^(2+)and Ce^(3+)doped phosphors for discovering novel violet-excited phosphors.A total of 822 phosphor data entries,including elemental compositions,crystal structures and excitation/emission wavelengths,have been extracted and validated from 9551 research papers.Compared with Ce^(3+)doped phosphors,the Eu^(2+)are in general more suited for violet-excited phosphors,as well as red-emitting phosphors.In particular,Eu^(2+)doped nitrides and sulfides are worth of exploration for violet-excited phosphors.This database is expected to be useful in the future development of phosphors for pc-WLEDs based on artificial intelligence methods.The datasets in this article are listed in Science Data Bank at http://doi.org/10.57760/sciencedb.34314.展开更多
Cyclohexene is an important raw material in the production of nylon.Selective hydrogenation of benzene is a key method for preparing cyclohexene.However,the Ru catalysts used in current industrial processes still face...Cyclohexene is an important raw material in the production of nylon.Selective hydrogenation of benzene is a key method for preparing cyclohexene.However,the Ru catalysts used in current industrial processes still face challenges,including high metal usage,high process costs,and low cyclohexene yield.This study utilizes existing literature data combined with machine learning methods to analyze the factors influencing benzene conversion,cyclohexene selectivity,and yield in the benzene hydrogenation to cyclohexene reaction.It constructs predictive models based on XGBoost and Random Forest algorithms.After analysis,it was found that reaction time,Ru content,and space velocity are key factors influencing cyclohexene yield,selectivity,and benzene conversion.Shapley Additive Explanations(SHAP)analysis and feature importance analysis further revealed the contribution of each variable to the reaction outcomes.Additionally,we randomly generated one million variable combinations using the Dirichlet distribution to attempt to predict high-yield catalyst formulations.This paper provides new insights into the application of machine learning in heterogeneous catalysis and offers some reference for further research.展开更多
Near-infrared image sensors are widely used in fields such as material identification,machine vision,and autonomous driving.Lead sulfide colloidal quantum dot-based infrared photodiodes can be integrated with sil⁃icon...Near-infrared image sensors are widely used in fields such as material identification,machine vision,and autonomous driving.Lead sulfide colloidal quantum dot-based infrared photodiodes can be integrated with sil⁃icon-based readout circuits in a single step.Based on this,we propose a photodiode based on an n-i-p structure,which removes the buffer layer and further simplifies the manufacturing process of quantum dot image sensors,thus reducing manufacturing costs.Additionally,for the noise complexity in quantum dot image sensors when capturing images,traditional denoising and non-uniformity methods often do not achieve optimal denoising re⁃sults.For the noise and stripe-type non-uniformity commonly encountered in infrared quantum dot detector imag⁃es,a network architecture has been developed that incorporates multiple key modules.This network combines channel attention and spatial attention mechanisms,dynamically adjusting the importance of feature maps to en⁃hance the ability to distinguish between noise and details.Meanwhile,the residual dense feature fusion module further improves the network's ability to process complex image structures through hierarchical feature extraction and fusion.Furthermore,the pyramid pooling module effectively captures information at different scales,improv⁃ing the network's multi-scale feature representation ability.Through the collaborative effect of these modules,the network can better handle various mixed noise and image non-uniformity issues.Experimental results show that it outperforms the traditional U-Net network in denoising and image correction tasks.展开更多
The single-event susceptibility of three silicon carbide(SiC)metal-oxide-semiconductor field-effect transistor(MOSFET)power devices structures(planar,trench and double trench)is researched by the technology computer-a...The single-event susceptibility of three silicon carbide(SiC)metal-oxide-semiconductor field-effect transistor(MOSFET)power devices structures(planar,trench and double trench)is researched by the technology computer-aided design(TCAD)simulation.Comparative analysis of the heavy-ion irradiation effects on three device structures reveals distinct susceptibility characteristics.The gate oxide region is identified as the most sensitive position in planar devices,while trench and doubletrench structures exhibit no localized sensitive regions.Furthermore,the single-event susceptibility demonstrates strong depth dependence across all three structures,with enhanced vulnerability observed at greater ion penetration depths.展开更多
Silicon carbide fibers are considered ideal reinforcing materials for ceramic matrix composites due to their excellent mechanical properties and high-temperature performance.Different types of fibers necessitate indiv...Silicon carbide fibers are considered ideal reinforcing materials for ceramic matrix composites due to their excellent mechanical properties and high-temperature performance.Different types of fibers necessitate individual investigation due to variations in their composition and fabrication processes.This study presents a comprehensive investigation into evolution of the mechanical properties,surface microstructure,and composition of Shicolon-Ⅱ fibers subjected to argon heat treatment at temperatures ranging from 1300℃to 1700℃.The Shicolon-Ⅱ fibers are composed of small-sized β-SiC grains,SiC_(x)O_(y) amorphous phase,and a minor amount of graphite microcrystals.Following treatment in an argon atmosphere at 1300℃,the fibers maintain a monofilament tensile strength of 3.620 GPa,corresponding to a retention of 98.32%.This strength diminishes to 2.875 GPa,equating to a retention of 78.08%,after treatment at 1500℃.The reduction in mechanical properties of the fibers can be ascribed to the decomposition of the amorphous phase and the growth of β-SiC grains.Furthermore,creep resistance is an essential factor influencing the long-term performance of composite materials.After treatment at temperatures above 1400℃,the high-temperature creep resistance of the fibers is significantly enhanced due to growth of β-SiC grains.This study offers valuable theoretical insights into high-temperature applications of second-generation fibers,contributing to an enhanced understanding of their performance under extreme conditions.展开更多
In addition to its well-known fossils,the Upper Miocene Baogeda Ula Formation is coupled with multiple basaltic lava flows,creating an ideal setting for studying its depositional history,geochronology,and associated v...In addition to its well-known fossils,the Upper Miocene Baogeda Ula Formation is coupled with multiple basaltic lava flows,creating an ideal setting for studying its depositional history,geochronology,and associated vertebrate fossils.This paper,in honor of Prof.Qiu Zhanxiang for his widely admired emphasis on the geological contexts of vertebrate fossils,attempts to synthesize known contact relationships,existing K-Ar dates,and capping basalt elevations to reframe our concept of the lithostratigraphy,magnetostratigraphy,and lateral distribution of the Baogeda Ula Formation.Within this new framework,the Baogeda Ula Formation is defined by unconformable contact with the underlying Tunggur Formation at the lower boundary and a capping basalt at the upper boundary.In many sections,two or three layers of basalts are interbedded within sedimentary strata,with the capping basalts typically belonging to the top two basalts.The newly defined Baogeda Ula Formation includes a lower member as exemplified by Halajin Hushu section and Ulan Hushuyin Nur section,and an upper member at Baogeda Ula section.This expanded concept of the Baogeda Ula Formation includes two major faunas,i.e.,the Bahean Halajin Hushu Fauna and Baodean Baogeda Ula Fauna,both falling within the Upper Miocene.We also describe rare fossil skunks(Promephitis)found in recent years that support the age assessments presented herein.展开更多
To investigate the long-term stability of soft-hard interbedded rock masses with initial damage induced by earthquakes and periodic drying and wetting,this study prepared samples with different initial damage through ...To investigate the long-term stability of soft-hard interbedded rock masses with initial damage induced by earthquakes and periodic drying and wetting,this study prepared samples with different initial damage through cyclic loading and unloading(CLU)experiments followed by cyclic drying and wetting(CDW)experiments,and finally conducted creep experiments.The study analyzed the effects of initial damage on creep mechanical behavior,crack evolution,and explored failure precursor information,revealing the damage failure mechanisms.The results show that the structural characteristics of the rock mass control its macroscopic failure mode.Initial damage promotes microcrack development,influences the fracture mode,and increases the proportion of high-frequency(200−280 kHz)acoustic emission events during creep.Meanwhile,initial damage exacerbates creep characteristics,increasing the creep rate,shortening total creep failure time,and reducing long-term strength.The damage failure is attributed to:the generation of internal cracks and pores in the rock caused by CLU;mineral hydrolysis and expansion-contraction due to CDW,resulting in weakened intergranular cementation;and full development of cracks and pores under creep stress.Additionally,the deformation difference coefficient and the coefficient of variation of RA/AF values can serve as precursor indicators for creep failure.展开更多
A controversial taxon,Hipparion plocodus,is reviewed in the present study.Hi.plocodus has been confirmed to be a valid species with definite diagnostic characteristics,represented by cranial specimens from Baode,Shanx...A controversial taxon,Hipparion plocodus,is reviewed in the present study.Hi.plocodus has been confirmed to be a valid species with definite diagnostic characteristics,represented by cranial specimens from Baode,Shanxi Province.The phylogenetic analysis performed in the present study,with a new matrix,shows that Hi.plocodus forms a monophyletic group with a European species,Hippotherium malpassii.Actually,no close relationship between so-called Hm.malpassii and the genus Hippotherium has been identified,and the record of stratigraphic range of this genus in late stage of Late Miocene is currently absent.Herein previously Hi.plocodus and Hm.malpassii have both attributed into“Hipparion”before the discovery of better material.Evolutionary stages and correlative absolute age showed that these two species should derive independently from some primitive clade.During the late stage of the Late Miocene,the development of the Asian summer monsoon enhanced the humidity of China,with forest and wood habitats expanding considerably under this setting.As the result,one Eurasian closed-habitat lineage thus extended its range into China,which had become very suited for it,give rise to“Hi.”plocodus.展开更多
The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave...The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave infrared wavelengths as beacon light can reduce atmospheric absorption and signal attenuation.However,there are strong non-uniformity and blind pixels in the short-wave infrared image,which makes the image distorted and leads to the decrease of spot centroid positioning accuracy.Therefore,the high-precision localization of the spot centroid of the short-wave infrared images is of great research significance.A high-precision spot centroid positioning model for short-wave infrared is proposed to correct for non-uniformity and blind pixels in short-wave infrared images and quantify the localization errors caused by the two,further model-based localization error simulations are performed,and a novel spot centroid positioning payload for satellite laser communications has been designed using the latest 640×512 planar array InGaAs shortwave infrared detector.The experimental results show that the non-uniformity of the corrected image is reduced from 7%to 0.6%,the blind pixels rejection rate reaches 100%,the frame rate can be up to 2000 Hz,and the spot centroid localization accuracy is as high as 0.1 pixel point,which realizes high-precision spot centroid localization of high-frame-frequency short-wave infrared images.展开更多
Crocuta and Pachycrocuta are widely regarded as the most prevalent and emblematic hyenas across Eurasia during Quaternary.They are easily distinguished by their distinctive carnassial teeth.However,the disparities in ...Crocuta and Pachycrocuta are widely regarded as the most prevalent and emblematic hyenas across Eurasia during Quaternary.They are easily distinguished by their distinctive carnassial teeth.However,the disparities in non-carnassial elements are less pronounced and have received minimal attention in previous studies.This has resulted in erroneous identifications when dealing with fragmented specimens,particularly in cases where carnassial teeth are poorly preserved or absent.Such misidentifications have the potential to give rise to erroneous inferences regarding the paleozoogeography and biochronology of the animals in question.The bone-cracking hyena specimens from Huainan,Anhui(Tseng et al.,2008)are re-examined and re-evaluated here through a series of morphological comparisons and data analyses(univariate,bivariate,and multivariate analyses etc.).The results provide unequivocal confirmation that the specimens from Xiliexi are not spotted hyenas,but belong to Pachycrocuta perrieri instead.Conversely,the specimen from Dadingshan is the only genuine representative of the spotted hyena,which is supposed to be a possible earliest fossil record for Crocuta ultima thus far in China.Furthermore,the disparities in dentognathic morphology between Crocuta and Pachycrocuta are systematically summarized and analyzed,with an explanation of their eco-functional significance.The present study hypothesizes that Pachycrocuta retains a certain degree of active predatory capability,attributable to the robustness of the canine and the symphysis of the jaw,among other factors.This finding indicates that Pachycrocuta exhibits a form of flexible foraging behavior,combining opportunistic scavenging and active hunting in a manner analogous to Crocuta.Finally,the dynamic evolutionary history of hyenas in East China since Pleistocene has also been broadly reconstructed.展开更多
Pitch produced by the lique-faction of coal was divided into two frac-tions:soluble in toluene(TS)and insol-uble in toluene but soluble in pyridine(TI-PS),and their differences in molecu-lar structure and oxidation ac...Pitch produced by the lique-faction of coal was divided into two frac-tions:soluble in toluene(TS)and insol-uble in toluene but soluble in pyridine(TI-PS),and their differences in molecu-lar structure and oxidation activity were studied.Several different carbon materi-als were produced from them by oxida-tion in air(350℃,300 mL/min)fol-lowed by carbonization(1000℃ in Ar),and the effect of the cross-linked structure on their structure and sodium storage properties was investigated.The results showed that the two pitch fractions were obviously different after the air oxidation.The TS fraction with a low degree of condensation and abundant side chains had a stronger oxidation activity and thus introduced more cross-linked oxygen-containing functional groups C(O)―O which prevented carbon layer rearrangement during the carbonization.As a result,a disordered hard carbon with more defects was formed,which improved the electrochemical performance.Therefore,the carbon materials derived from TS(O-TS-1000)had an obvious disordered structure and a larger layer spacing,giving them better sodium storage perform-ance than those derived from the TI-PS fraction(O-TI-PS-1000).The specific capacity of O-TS-1000 was about 250 mAh/g at 20 mA/g,which was 1.67 times higher than that of O-TI-PS-1000(150 mAh/g).展开更多
Suid is one of the most common taxa among the Pleistocene mammalian fauna in China.However,its phylogenetic taxonomy and evolution are far from clear.The newly recovered suid fossil materials from the Early Pleistocen...Suid is one of the most common taxa among the Pleistocene mammalian fauna in China.However,its phylogenetic taxonomy and evolution are far from clear.The newly recovered suid fossil materials from the Early Pleistocene Shanshenmiaozui site in Nihewan Basin in North China provide new insight into the evolution of its kind in North China.The new materials include partial skulls and mandibles of males,and most of their teeth were preserved in situ.The specimens can be referred to the species Sus lydekkeri,which is the only species of Sus found in North China from the Early Pleistocene.The fossils of the once reported Pleistocene species“Potamochoerus chinhsienensis”should also be provisionally included in the species S.lydekkeri according to its form and size,which at least now excludes it from Potamochoerus.The species S.lydekkeri is very close to the extant species S.scrofa,and even was combined into the latter as a chronological subspecies by some authors,while its larger size,prominent preorbital fossa,backwardly positioned infraorbital foramen,frequently appearing verrucosic type(at least the intermediate type of the male lower canine),and simple crown structures support its validness as an independent species.The Early Pleistocene forms are characterized by a larger size,lower L/W ratio of cheekteeth,both upper and lower M3s having no more than three lobes,and the male lower canine is exclusively of a verrucosic type.Suid fossils are a very good indicator of paleoenvironments and paleoclimate.Both the northern and the southern faunas in China contain suid fossils throughout the Pleistocene Epoch,while the southern fauna has prominently more diversified taxa and more abundant fossil collections;whether that is caused by different origins or by environmental modifications is still not clear.展开更多
Filter capacitors play an important role in altern-ating current(AC)-line filtering for stabilizing voltage,sup-pressing harmonics,and improving power quality.However,traditional aluminum electrolytic capacitors(AECs)...Filter capacitors play an important role in altern-ating current(AC)-line filtering for stabilizing voltage,sup-pressing harmonics,and improving power quality.However,traditional aluminum electrolytic capacitors(AECs)suffer from a large size,short lifespan,low power density,and poor reliability,which limits their use.In contrast,ultrafast supercapacitors(SCs)are ideal for replacing commercial AECs because of their extremely high power densities,fast charging and discharging,and excellent high-frequency re-sponse.We review the design principles and key parameters for ultrafast supercapacitors and summarize research pro-gress in recent years from the aspects of electrode materials,electrolytes,and device configurations.The preparation,structures,and frequency response performance of electrode materials mainly consisting of carbon materials such as graphene and carbon nanotubes,conductive polymers,and transition metal compounds,are focused on.Finally,future research directions for ultrafast SCs are suggested.展开更多
Prof.Qiu Zhanxiang’s academic life presents a cross regional scientific research landscape:born in Qingdao City on the coast of the Yellow Sea,he devoted his life to exploring the mysteries of terrestrial mammalian e...Prof.Qiu Zhanxiang’s academic life presents a cross regional scientific research landscape:born in Qingdao City on the coast of the Yellow Sea,he devoted his life to exploring the mysteries of terrestrial mammalian evolution.In his early years,he received systematic training at the Geological Department of Moscow University and graduated in 1960,which laid a solid disciplinary foundation for him.After returning to China,he took root in the Institute of Vertebrate Paleontology and Paleoanthropology,Chinese Academy of Sciences,starting a scientific research journey that lasted for more than half a century.As a paleontologist,his career has distinct international characteristics:from 1982 to 1984,he was awarded the Humboldt Scholarship from the Federal Republic of Germany and completed his doctoral thesis at the Gutenberg University of Mainz,and from 1982 to 1999,he conducted a series of international cooperation projects.His academic leadership was particularly prominent in his career,as he led multiple strategic scientific research projects during his tenure at the institute from 1991 to 1995.His scientific research footprint spans from the Nei Mongol Gobi to the Tibetan Plateau,and from the Yushe Basin in Shanxi Province to the Linxia Basin in Gansu Province.The National Climbing Plan of“Research on the origin of early human beings and environmental background”presided over by him has created a new paradigm of interdisciplinary research.In terms of disciplinary achievements,Prof.Qiu has achieved three landmark accomplishments:deciphering the evolutionary code of the Paleocene red bed mammalian fauna of South China,clarifying the lineage of giant rhino fossils,and establishing a biochronological scale for the Neogene terrestrial strata in China and conducting in-depth research on the carnivore and perissodactyl fossils contained therein.These achievements have provided a key evidence chain for analyzing the evolutionary mechanism of mammals’adaptation to environmental changes over 66 million years,which not only won him the title of CAS Academician in 2005,but also left China’s mark in the field of international Cenozoic paleontology and stratigraphy.展开更多
文摘Linsangs(Prionodon Horsfield,1822)are small,arboreal feliform carnivorans that live in the tropical and subtropical forests of Southeast Asia and southern China.Several lines of morphological evidence from the soft tissues,dentition,and basicranium support their placement in either Prionodontinae or Viverrinae of Viverridae.However,molecular evidence has not only excluded the linsangs from Viverridae but also established that they constitute a monogeneric family Prionodontidae sister to Felidae.For that reason,the examination of the skull osteology of linsangs and related taxa is necessary to better understand how morphological and molecular data-particularly morphology-have contributed to the reconstruction of the Feliformia phylogeny.During the summer field season in July of 2020,we stumbled across the carcass of a spotted linsang(P.pardicolor)in a karst cave on the outskirts of Chongzuo City.To contribute to the knowledge about the morphology of this enigmatic feliform carnivoran,we present a preliminary description of the exterior skull osteology of P.pardicolor.The craniodental morphology provides strong evidence for a closer phylogenetic relationship between P.pardicolor and Viverrinae.However,since both morphological and molecular approaches have inherent limitations,caution is urged when inferring feliform phylogeny based on either discipline alone.
文摘Eospalax,one of the only two extant genera within the Myospalacinae,has a high species richness.Each species is distinguished by unique cranial and dental morphologies,as well as variations in temporal and spatial distribution.Consequently,Eospalax serves as a reliable indicator for the biochronologic and paleoenvironmental studies of the Quaternary of East Asia.A recent discovery of a complete fossil skull in a conglomerate deposit,a part of the Lower Pleistocene Sanmen Formation,near Jianyucha Town,Zichang County,northern Shaanxi Province,has been subjected to a detailed analysis.The specimens were identified as Eospalax simplicidens,an extinct species of Eospalax,based on dental morphology.The recent discovery of E.simplicidens in Jianyucha offers significant insights into the species’cranial morphology and contributes to a more comprehensive understanding of its geographical distribution.The distinctive feature of the posterodorsal location of the external acoustic meatus indicates either a plesiomorphy or an evolutionary convergence among E.simplicidens,African root rats(Tachyoryctes),and bamboo rats(Rhizomyini).A skull(IVPP V5398.1)and four upper jaws(V5398.2)from Gongwangling in Lantian,Shaanxi,previously identified as Myospalax fontanieri,is transferred to the species E.lingtaiensis.A skull(IVPP RV35055)from Jingou,Xin’an,Henan,previously identified as E.simplicidens,is transferred to the species E.youngianus.In this study,body mass estimates are made for extinct Eospalax.Both E.lingtaiensis and E.simplicidens are small-sized zokors,with an estimated body mass of less than or approximately 300 g,respectively.
基金supported by National Key R&D Program of China (2022YFD1900104)。
文摘To maintain soil quality under long-term saline water irrigation,the influence of manure on soil physical properties was examined.Long-term saline irrigation has been conducted from 2015 to 2024 at the Nanpi Eco-Agricultural Experimental Station of Chinese Academy Sciences in the Low Plain of the North China Plain,comprising four irrigation treatments:irrigation once at the jointing stage for winter wheat with irrigation water containing salt at fresh water,3,4 and 5 g·L^(–1),and maize irrigation at sowing using fresh water.Manure application was conducted under all irrigation treatments,with treatments without manure application used as controls.The results showed that under long-term irrigation with saline water,the application of manure increased the soil organic matter content,exchangeable potassium,available phosphorus,and total nitrogen content in the 0–20 cm soil layer by 46.8%,117.0%,75.7%,and 45.5%,respectively,compared to treatments without manure application.The application of manure reduced soil bulk density.It also increased the proportion of water-stable aggregates and the abundance of bacteria,fungi,and actinomycetes in the tillage soil layer compared to the controls.Because of the salt contained in the manure,the application of manure had dual effects on soil salt content.During the winter wheat season,manure application increased soil salt content.The salt content was significantly reduced during the summer maize season,owing to the strong salt-leaching effects under manure application,resulting in a smaller difference in salt content between the manure and non-manure treatments.During the summer rainfall season,improvements in soil structure under manure application increased the soil desalination rate for the 1 m top soil layer.The desalination rate for 0–40 cm and 40–100 cm was averagely by 39.1%and 18.9%higher,respectively,under manure application as compared with that under the nomanure treatments.The yield of winter wheat under manure application was 0.12%lower than that of the control,owing to the higher salt content during the winter wheat season.In contrast,the yield of summer maize improved by 3.9%under manure application,owing to the increased soil nutrient content and effective salt leaching.The results of this study indicated that manure application helped maintain the soil physical structure,which is important for the long-term use of saline water.In practice,using manure with a low salt content is suggested to reduce the adverse effects of saline water irrigation on soil properties and achieve sustainable saline water use.
文摘Antilospira is a small to medium-sized antelope with heteronymously spiraled horn cores.It was widely distributed in northern China from the Late Pliocene to the Early Pleistocene.It is a typical fossil bovid with important implications for biostratigraphy and antilopin evolution in China.Antilospira robusta is a species with highly fragmentary materials and has previously only been briefly discussed.Here we report on a new frontal with horn cores from the Early Pleistocene Wucheng Loess in Nalesi Township,Dongxiang Autonomous County,Linxia Basin,Gansu Province.This new material features heteronymously spiraled horn cores,deep longitudinal grooves,a sharp anterior carena on the horn core,and a large body size,which are characteristics similar to those of A.robusta.However,the horn base of the new material is more compressed than all the previously discovered spiral-horned antelopes,so we attributed it to Antilospira cf.A.robusta.This is the first time Antilospira has been found in northwestern China,and this discovery provides more morphological data for the classification of this group.CT scans of the horn core reveal the well-remodeled horn core trabeculae in Antilospira,which is different from what is observed in Spirocerus.The frontal sinuses are moderately developed in the Linxia specimen,extending backwards to the orbit but not to the horn base.The virtual reconstruction of the endocranial cast indicated that Antilospira has bending and narrow frontal lobes,wide temporal lobes,and relatively complex sulci on the cerebral hemisphere,which differ from extant Antilopini bovids in China.
基金Supported by the Natural Science Foundation of Shanxi Province(202203021221303)the Science and Technology Major Project of Shanxi Province(202005D121002)the Science and Technology Cooperation and Communication Project of Shanxi Province(202304041101016)。
文摘Propylene oxide(PO)is an important petrochemical materials used to produce downstream products such as propylene glycol(PG),polyether polyols,and dipropylene glycol(DPG).Among these,DPG is commonly used as a solvent for fragrances,cosmetics,food additives,and detergents,and can also be served as a moisturizer in cosmetics,showing broad application prospects.The distribution of DPG isomers in the products synthesized from PO and PG has a significant impactΔrGΔrHΔfHθΔfGθPO+PG⇌DPG PO+DPG⇌TPG PG+PG⇌DPG+H_(2)O PG+DPG⇌TPG+H_(2)O on the quality of the products.Therefore,conducting thermodynamic calculation on the reaction of PO and PG to synthesize DPG can provide a theoretical basis for practical operations and product distribution regulation.So,in this paper,the thermodynamic parameters of PO,1,2-PG,H_(2)O,tripropylene glycol(TPG)and three isomers of DPG under different reaction conditions is calculated.Additionally,the,and lnK for four potential reactions at various reaction temperatures and pressures are calculated.By designing isodesmic reactions and combining the results of thermodynamic calculations,the and for the isomers of DPG are obtained,and the relative error is less than 7%.The results show that in the process of preparing DPG by PO and PG,when PO∶PG=1,the reaction temperature ranges from 298.15 to 413.15 K,and the pressure ranges from 101.325 to 506.625 kPa,the reactions of and are thermodynamically spontaneous.While the reactions of and are thermodynamically unspontaneous.The optimal reaction temperature and pressure are 413.15 K and 101.325 kPa.The thermodynamic stability of the three isomers is DPG1>DPG2>DPG3 under standard conditions.The accuracy of the computational results is verified through experimental design,and based on this,the factors affecting product distribution are analyzed.
基金National Key Research and Development Program of China(2021YFB3500501)。
文摘Commercial phosphor-converted white LEDs(pc-WLEDs)face two inherent limitations,namely blue light hazard and low color rendering index,due to the use of blue LEDs as excitation source.To address these challenges,violet LEDs are proposed as an alternative solution.Currently,phosphors that can be efficiently excited by violet light(with wavelengths from 400 to 420 nm)remain under development still.In this study,we utilize large language models to construct a comprehensive database of Eu^(2+)and Ce^(3+)doped phosphors for discovering novel violet-excited phosphors.A total of 822 phosphor data entries,including elemental compositions,crystal structures and excitation/emission wavelengths,have been extracted and validated from 9551 research papers.Compared with Ce^(3+)doped phosphors,the Eu^(2+)are in general more suited for violet-excited phosphors,as well as red-emitting phosphors.In particular,Eu^(2+)doped nitrides and sulfides are worth of exploration for violet-excited phosphors.This database is expected to be useful in the future development of phosphors for pc-WLEDs based on artificial intelligence methods.The datasets in this article are listed in Science Data Bank at http://doi.org/10.57760/sciencedb.34314.
基金Supported by CAS Basic and Interdisciplinary Frontier Scientific Research Pilot Project(XDB1190300,XDB1190302)Youth Innovation Promotion Association CAS(Y2021056)+1 种基金Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy(YLU-DNL Fund 2022007)The special fund for Science and Technology Innovation Teams of Shanxi Province(202304051001007)。
文摘Cyclohexene is an important raw material in the production of nylon.Selective hydrogenation of benzene is a key method for preparing cyclohexene.However,the Ru catalysts used in current industrial processes still face challenges,including high metal usage,high process costs,and low cyclohexene yield.This study utilizes existing literature data combined with machine learning methods to analyze the factors influencing benzene conversion,cyclohexene selectivity,and yield in the benzene hydrogenation to cyclohexene reaction.It constructs predictive models based on XGBoost and Random Forest algorithms.After analysis,it was found that reaction time,Ru content,and space velocity are key factors influencing cyclohexene yield,selectivity,and benzene conversion.Shapley Additive Explanations(SHAP)analysis and feature importance analysis further revealed the contribution of each variable to the reaction outcomes.Additionally,we randomly generated one million variable combinations using the Dirichlet distribution to attempt to predict high-yield catalyst formulations.This paper provides new insights into the application of machine learning in heterogeneous catalysis and offers some reference for further research.
基金Supported by the National key research and development program in the 14th five year plan 2021YFA1200700)the National Natural Science Foundation of China(62535018,62431025,62561160113)the Natural Science Foundation of Shanghai(23ZR1473400).
文摘Near-infrared image sensors are widely used in fields such as material identification,machine vision,and autonomous driving.Lead sulfide colloidal quantum dot-based infrared photodiodes can be integrated with sil⁃icon-based readout circuits in a single step.Based on this,we propose a photodiode based on an n-i-p structure,which removes the buffer layer and further simplifies the manufacturing process of quantum dot image sensors,thus reducing manufacturing costs.Additionally,for the noise complexity in quantum dot image sensors when capturing images,traditional denoising and non-uniformity methods often do not achieve optimal denoising re⁃sults.For the noise and stripe-type non-uniformity commonly encountered in infrared quantum dot detector imag⁃es,a network architecture has been developed that incorporates multiple key modules.This network combines channel attention and spatial attention mechanisms,dynamically adjusting the importance of feature maps to en⁃hance the ability to distinguish between noise and details.Meanwhile,the residual dense feature fusion module further improves the network's ability to process complex image structures through hierarchical feature extraction and fusion.Furthermore,the pyramid pooling module effectively captures information at different scales,improv⁃ing the network's multi-scale feature representation ability.Through the collaborative effect of these modules,the network can better handle various mixed noise and image non-uniformity issues.Experimental results show that it outperforms the traditional U-Net network in denoising and image correction tasks.
基金National Key Research and Development Program of China(2023YFA1609000)National Natural Science Foundation of China(62474190,U22B2043,U2267210)。
文摘The single-event susceptibility of three silicon carbide(SiC)metal-oxide-semiconductor field-effect transistor(MOSFET)power devices structures(planar,trench and double trench)is researched by the technology computer-aided design(TCAD)simulation.Comparative analysis of the heavy-ion irradiation effects on three device structures reveals distinct susceptibility characteristics.The gate oxide region is identified as the most sensitive position in planar devices,while trench and doubletrench structures exhibit no localized sensitive regions.Furthermore,the single-event susceptibility demonstrates strong depth dependence across all three structures,with enhanced vulnerability observed at greater ion penetration depths.
基金National Natural Science Foundation of China(52172108)National Key R&D Program of China(2022YFB3707700)Strategic Priority Research Program of the Chinese Academy of Sciences(XDC0144005)。
文摘Silicon carbide fibers are considered ideal reinforcing materials for ceramic matrix composites due to their excellent mechanical properties and high-temperature performance.Different types of fibers necessitate individual investigation due to variations in their composition and fabrication processes.This study presents a comprehensive investigation into evolution of the mechanical properties,surface microstructure,and composition of Shicolon-Ⅱ fibers subjected to argon heat treatment at temperatures ranging from 1300℃to 1700℃.The Shicolon-Ⅱ fibers are composed of small-sized β-SiC grains,SiC_(x)O_(y) amorphous phase,and a minor amount of graphite microcrystals.Following treatment in an argon atmosphere at 1300℃,the fibers maintain a monofilament tensile strength of 3.620 GPa,corresponding to a retention of 98.32%.This strength diminishes to 2.875 GPa,equating to a retention of 78.08%,after treatment at 1500℃.The reduction in mechanical properties of the fibers can be ascribed to the decomposition of the amorphous phase and the growth of β-SiC grains.Furthermore,creep resistance is an essential factor influencing the long-term performance of composite materials.After treatment at temperatures above 1400℃,the high-temperature creep resistance of the fibers is significantly enhanced due to growth of β-SiC grains.This study offers valuable theoretical insights into high-temperature applications of second-generation fibers,contributing to an enhanced understanding of their performance under extreme conditions.
文摘In addition to its well-known fossils,the Upper Miocene Baogeda Ula Formation is coupled with multiple basaltic lava flows,creating an ideal setting for studying its depositional history,geochronology,and associated vertebrate fossils.This paper,in honor of Prof.Qiu Zhanxiang for his widely admired emphasis on the geological contexts of vertebrate fossils,attempts to synthesize known contact relationships,existing K-Ar dates,and capping basalt elevations to reframe our concept of the lithostratigraphy,magnetostratigraphy,and lateral distribution of the Baogeda Ula Formation.Within this new framework,the Baogeda Ula Formation is defined by unconformable contact with the underlying Tunggur Formation at the lower boundary and a capping basalt at the upper boundary.In many sections,two or three layers of basalts are interbedded within sedimentary strata,with the capping basalts typically belonging to the top two basalts.The newly defined Baogeda Ula Formation includes a lower member as exemplified by Halajin Hushu section and Ulan Hushuyin Nur section,and an upper member at Baogeda Ula section.This expanded concept of the Baogeda Ula Formation includes two major faunas,i.e.,the Bahean Halajin Hushu Fauna and Baodean Baogeda Ula Fauna,both falling within the Upper Miocene.We also describe rare fossil skunks(Promephitis)found in recent years that support the age assessments presented herein.
基金Project(U22A20603)supported by the National Natural Science Foundation of ChinaProject(2023YFC3008300)supported by the National Key Research and Development Program of China。
文摘To investigate the long-term stability of soft-hard interbedded rock masses with initial damage induced by earthquakes and periodic drying and wetting,this study prepared samples with different initial damage through cyclic loading and unloading(CLU)experiments followed by cyclic drying and wetting(CDW)experiments,and finally conducted creep experiments.The study analyzed the effects of initial damage on creep mechanical behavior,crack evolution,and explored failure precursor information,revealing the damage failure mechanisms.The results show that the structural characteristics of the rock mass control its macroscopic failure mode.Initial damage promotes microcrack development,influences the fracture mode,and increases the proportion of high-frequency(200−280 kHz)acoustic emission events during creep.Meanwhile,initial damage exacerbates creep characteristics,increasing the creep rate,shortening total creep failure time,and reducing long-term strength.The damage failure is attributed to:the generation of internal cracks and pores in the rock caused by CLU;mineral hydrolysis and expansion-contraction due to CDW,resulting in weakened intergranular cementation;and full development of cracks and pores under creep stress.Additionally,the deformation difference coefficient and the coefficient of variation of RA/AF values can serve as precursor indicators for creep failure.
文摘A controversial taxon,Hipparion plocodus,is reviewed in the present study.Hi.plocodus has been confirmed to be a valid species with definite diagnostic characteristics,represented by cranial specimens from Baode,Shanxi Province.The phylogenetic analysis performed in the present study,with a new matrix,shows that Hi.plocodus forms a monophyletic group with a European species,Hippotherium malpassii.Actually,no close relationship between so-called Hm.malpassii and the genus Hippotherium has been identified,and the record of stratigraphic range of this genus in late stage of Late Miocene is currently absent.Herein previously Hi.plocodus and Hm.malpassii have both attributed into“Hipparion”before the discovery of better material.Evolutionary stages and correlative absolute age showed that these two species should derive independently from some primitive clade.During the late stage of the Late Miocene,the development of the Asian summer monsoon enhanced the humidity of China,with forest and wood habitats expanding considerably under this setting.As the result,one Eurasian closed-habitat lineage thus extended its range into China,which had become very suited for it,give rise to“Hi.”plocodus.
基金Supported by the Short-wave Infrared Camera Systems(B025F40622024)。
文摘The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave infrared wavelengths as beacon light can reduce atmospheric absorption and signal attenuation.However,there are strong non-uniformity and blind pixels in the short-wave infrared image,which makes the image distorted and leads to the decrease of spot centroid positioning accuracy.Therefore,the high-precision localization of the spot centroid of the short-wave infrared images is of great research significance.A high-precision spot centroid positioning model for short-wave infrared is proposed to correct for non-uniformity and blind pixels in short-wave infrared images and quantify the localization errors caused by the two,further model-based localization error simulations are performed,and a novel spot centroid positioning payload for satellite laser communications has been designed using the latest 640×512 planar array InGaAs shortwave infrared detector.The experimental results show that the non-uniformity of the corrected image is reduced from 7%to 0.6%,the blind pixels rejection rate reaches 100%,the frame rate can be up to 2000 Hz,and the spot centroid localization accuracy is as high as 0.1 pixel point,which realizes high-precision spot centroid localization of high-frame-frequency short-wave infrared images.
文摘Crocuta and Pachycrocuta are widely regarded as the most prevalent and emblematic hyenas across Eurasia during Quaternary.They are easily distinguished by their distinctive carnassial teeth.However,the disparities in non-carnassial elements are less pronounced and have received minimal attention in previous studies.This has resulted in erroneous identifications when dealing with fragmented specimens,particularly in cases where carnassial teeth are poorly preserved or absent.Such misidentifications have the potential to give rise to erroneous inferences regarding the paleozoogeography and biochronology of the animals in question.The bone-cracking hyena specimens from Huainan,Anhui(Tseng et al.,2008)are re-examined and re-evaluated here through a series of morphological comparisons and data analyses(univariate,bivariate,and multivariate analyses etc.).The results provide unequivocal confirmation that the specimens from Xiliexi are not spotted hyenas,but belong to Pachycrocuta perrieri instead.Conversely,the specimen from Dadingshan is the only genuine representative of the spotted hyena,which is supposed to be a possible earliest fossil record for Crocuta ultima thus far in China.Furthermore,the disparities in dentognathic morphology between Crocuta and Pachycrocuta are systematically summarized and analyzed,with an explanation of their eco-functional significance.The present study hypothesizes that Pachycrocuta retains a certain degree of active predatory capability,attributable to the robustness of the canine and the symphysis of the jaw,among other factors.This finding indicates that Pachycrocuta exhibits a form of flexible foraging behavior,combining opportunistic scavenging and active hunting in a manner analogous to Crocuta.Finally,the dynamic evolutionary history of hyenas in East China since Pleistocene has also been broadly reconstructed.
文摘Pitch produced by the lique-faction of coal was divided into two frac-tions:soluble in toluene(TS)and insol-uble in toluene but soluble in pyridine(TI-PS),and their differences in molecu-lar structure and oxidation activity were studied.Several different carbon materi-als were produced from them by oxida-tion in air(350℃,300 mL/min)fol-lowed by carbonization(1000℃ in Ar),and the effect of the cross-linked structure on their structure and sodium storage properties was investigated.The results showed that the two pitch fractions were obviously different after the air oxidation.The TS fraction with a low degree of condensation and abundant side chains had a stronger oxidation activity and thus introduced more cross-linked oxygen-containing functional groups C(O)―O which prevented carbon layer rearrangement during the carbonization.As a result,a disordered hard carbon with more defects was formed,which improved the electrochemical performance.Therefore,the carbon materials derived from TS(O-TS-1000)had an obvious disordered structure and a larger layer spacing,giving them better sodium storage perform-ance than those derived from the TI-PS fraction(O-TI-PS-1000).The specific capacity of O-TS-1000 was about 250 mAh/g at 20 mA/g,which was 1.67 times higher than that of O-TI-PS-1000(150 mAh/g).
文摘Suid is one of the most common taxa among the Pleistocene mammalian fauna in China.However,its phylogenetic taxonomy and evolution are far from clear.The newly recovered suid fossil materials from the Early Pleistocene Shanshenmiaozui site in Nihewan Basin in North China provide new insight into the evolution of its kind in North China.The new materials include partial skulls and mandibles of males,and most of their teeth were preserved in situ.The specimens can be referred to the species Sus lydekkeri,which is the only species of Sus found in North China from the Early Pleistocene.The fossils of the once reported Pleistocene species“Potamochoerus chinhsienensis”should also be provisionally included in the species S.lydekkeri according to its form and size,which at least now excludes it from Potamochoerus.The species S.lydekkeri is very close to the extant species S.scrofa,and even was combined into the latter as a chronological subspecies by some authors,while its larger size,prominent preorbital fossa,backwardly positioned infraorbital foramen,frequently appearing verrucosic type(at least the intermediate type of the male lower canine),and simple crown structures support its validness as an independent species.The Early Pleistocene forms are characterized by a larger size,lower L/W ratio of cheekteeth,both upper and lower M3s having no more than three lobes,and the male lower canine is exclusively of a verrucosic type.Suid fossils are a very good indicator of paleoenvironments and paleoclimate.Both the northern and the southern faunas in China contain suid fossils throughout the Pleistocene Epoch,while the southern fauna has prominently more diversified taxa and more abundant fossil collections;whether that is caused by different origins or by environmental modifications is still not clear.
文摘Filter capacitors play an important role in altern-ating current(AC)-line filtering for stabilizing voltage,sup-pressing harmonics,and improving power quality.However,traditional aluminum electrolytic capacitors(AECs)suffer from a large size,short lifespan,low power density,and poor reliability,which limits their use.In contrast,ultrafast supercapacitors(SCs)are ideal for replacing commercial AECs because of their extremely high power densities,fast charging and discharging,and excellent high-frequency re-sponse.We review the design principles and key parameters for ultrafast supercapacitors and summarize research pro-gress in recent years from the aspects of electrode materials,electrolytes,and device configurations.The preparation,structures,and frequency response performance of electrode materials mainly consisting of carbon materials such as graphene and carbon nanotubes,conductive polymers,and transition metal compounds,are focused on.Finally,future research directions for ultrafast SCs are suggested.
文摘Prof.Qiu Zhanxiang’s academic life presents a cross regional scientific research landscape:born in Qingdao City on the coast of the Yellow Sea,he devoted his life to exploring the mysteries of terrestrial mammalian evolution.In his early years,he received systematic training at the Geological Department of Moscow University and graduated in 1960,which laid a solid disciplinary foundation for him.After returning to China,he took root in the Institute of Vertebrate Paleontology and Paleoanthropology,Chinese Academy of Sciences,starting a scientific research journey that lasted for more than half a century.As a paleontologist,his career has distinct international characteristics:from 1982 to 1984,he was awarded the Humboldt Scholarship from the Federal Republic of Germany and completed his doctoral thesis at the Gutenberg University of Mainz,and from 1982 to 1999,he conducted a series of international cooperation projects.His academic leadership was particularly prominent in his career,as he led multiple strategic scientific research projects during his tenure at the institute from 1991 to 1995.His scientific research footprint spans from the Nei Mongol Gobi to the Tibetan Plateau,and from the Yushe Basin in Shanxi Province to the Linxia Basin in Gansu Province.The National Climbing Plan of“Research on the origin of early human beings and environmental background”presided over by him has created a new paradigm of interdisciplinary research.In terms of disciplinary achievements,Prof.Qiu has achieved three landmark accomplishments:deciphering the evolutionary code of the Paleocene red bed mammalian fauna of South China,clarifying the lineage of giant rhino fossils,and establishing a biochronological scale for the Neogene terrestrial strata in China and conducting in-depth research on the carnivore and perissodactyl fossils contained therein.These achievements have provided a key evidence chain for analyzing the evolutionary mechanism of mammals’adaptation to environmental changes over 66 million years,which not only won him the title of CAS Academician in 2005,but also left China’s mark in the field of international Cenozoic paleontology and stratigraphy.
