The long-term strength retrogression of silica-enriched oil well cement poses a significant threat to wellbore integrity in deep and ultra-deep wells, which is a major obstacle for deep petroleum and geothermal energy...The long-term strength retrogression of silica-enriched oil well cement poses a significant threat to wellbore integrity in deep and ultra-deep wells, which is a major obstacle for deep petroleum and geothermal energy development. Previous attempts to address this problem has been unsatisfactory because they can only reduce the strength decline rate. This study presents a new solution to this problem by incorporating fly ash to the traditional silica-cement systems. The influences of fly ash and silica on the strength retrogression behavior of oil well cement systems directly set and cured under the condition of 200°C and 50 MPa are investigated. Test results indicate that the slurries containing only silica or fly ash experience severe strength retrogression from 2 to 30 d curing, while the slurries containing both fly ash and silica experience strength enhancement from 2 to 90 d. The strength test results are corroborated by further evidences from permeability tests as well as microstructure analysis of set cement. Composition of set cement evaluated by quantitative X-ray diffraction analyses with partial or no known crystal structure(PONKCS) method and thermogravimetry analyses revealed that the conversion of amorphous C-(A)-S-H to crystalline phases is the primary cause of long-term strength retrogression.The addition of fly ash can reduce the initial amount of C-(A)-S-H in the set cement, and its combined use with silica can prevent the crystallization of C-(A)-S-H, which is believed to be the working mechanism of this new admixture in improving long-term strength stability of oil well cement systems.展开更多
Background Ongoing debates question the harm of internet use with the evolving technology,as many individuals transition from regular to problematic internet use(PIU).The habenula(Hb),located between the thalamus and ...Background Ongoing debates question the harm of internet use with the evolving technology,as many individuals transition from regular to problematic internet use(PIU).The habenula(Hb),located between the thalamus and the third ventricle,is implicated in various psychiatric disorders.In addition,personality features have been suggested to play a role in the pathophysiology of PIU.Aims This study aimed to investigate Hb volumetry in individuals with subclinical PIU and the mediating effect of personality traits on this relationship.Methods 110 healthy adults in this cross-sectional study underwent structural magnetic resonance imaging.Hb segmentation was performed using a deep learning technique.The Internet Addiction Test(IAT)and the NEO Five-Factor Inventory were used to assess the PIU level and personality,respectively.Partial Spearman's correlation analyses were performed to explore the reiationships between Hb volumetry,IAT and NEO.Multiple regression analysis was applied to identify personality traits that predict IAT scores.The significant trait was then treated as a mediator between Hb volume and IAT correlation in mediation analysis with a bootstrap value of 5000.Results Relative Hb volume was negatively correlated with IAT scores(partial rho=-0.142,p=0.009).The IAT score was positively correlated with neuroticism(partial rho=0.430,p<0.001)and negatively correlated with extraversion,agreeableness and conscientiousness(partial rho=-0.213,p<0.001;partial rho=-0.279,p<0.001;and partial rho=-0.327,p<0.001).There was a significant indirect effect of Hb volume on this model(β=-0.061,p=0.048,boot 95%confidence interval:-0.149 to-0.001).Conclusions This study uncovered a crucial link between reduced Hb volume and heightened PIU.Our findings highlight neuroticism as a key risk factor for developing PIU.Moreover,neuroticism was shown to mediate the relationship between Hb volume and PIU tendency,offering valuable insight into the complexities of this interaction.展开更多
This study was performed to investigate the changes in microbial communities and metabolites during the long-term fermentation of commercially manufactured anchovy sauce.Samples of commercial anchovy sauce were collec...This study was performed to investigate the changes in microbial communities and metabolites during the long-term fermentation of commercially manufactured anchovy sauce.Samples of commercial anchovy sauce were collected from large-scale fermentation tanks with fermentation periods of up to 7.87 years.The complex bacterial community was simplified to two genera,Tetragenococcus and Halanaerobium,after approximately 0.55 years of fermentation.Although genera,such as Saccharomyces,Cladosporium,Candida,and Aspergillus,were relatively dominant,no clear pattern was identified in fungal community analysis.The longitudinal metabolite profile demonstrated that approximately half(55.8%)of the metabolites present in anchovy sauce were produced within a year of fermentation due to rapid fermentation.Despite the static microbial community,the contents of several metabolites including amino acids and biogenic amines changed continuously during the long-term fermentation of anchovy sauce.This study provides novel insights into the changes in microbiota and metabolites in fish sauce produced without any starter inoculation.展开更多
The safe and reliable operation of lithium-ion batteries necessitates the accurate prediction of remaining useful life(RUL).However,this task is challenging due to the diverse ageing mechanisms,various operating condi...The safe and reliable operation of lithium-ion batteries necessitates the accurate prediction of remaining useful life(RUL).However,this task is challenging due to the diverse ageing mechanisms,various operating conditions,and limited measured signals.Although data-driven methods are perceived as a promising solution,they ignore intrinsic battery physics,leading to compromised accuracy,low efficiency,and low interpretability.In response,this study integrates domain knowledge into deep learning to enhance the RUL prediction performance.We demonstrate accurate RUL prediction using only a single charging curve.First,a generalisable physics-based model is developed to extract ageing-correlated parameters that can describe and explain battery degradation from battery charging data.The parameters inform a deep neural network(DNN)to predict RUL with high accuracy and efficiency.The trained model is validated under 3 types of batteries working under 7 conditions,considering fully charged and partially charged cases.Using data from one cycle only,the proposed method achieves a root mean squared error(RMSE)of 11.42 cycles and a mean absolute relative error(MARE)of 3.19%on average,which are over45%and 44%lower compared to the two state-of-the-art data-driven methods,respectively.Besides its accuracy,the proposed method also outperforms existing methods in terms of efficiency,input burden,and robustness.The inherent relationship between the model parameters and the battery degradation mechanism is further revealed,substantiating the intrinsic superiority of the proposed method.展开更多
Atmospheric nitrogen(N)deposition is predicted to increase,especially in the subtropics.However,the responses of soil microorganisms to long-term N addition at the molecular level in N-rich subtropical forests have no...Atmospheric nitrogen(N)deposition is predicted to increase,especially in the subtropics.However,the responses of soil microorganisms to long-term N addition at the molecular level in N-rich subtropical forests have not been clarified.A long-term nutrient addition experiment was conducted in a subtropical evergreen old-growth forest in China.The four treatments were:control,low N(50 kg N ha^(-1)a^(-1)),high N(100 kg N ha^(-1)a^(-1)),and combined N and phosphorus(P)(100 kg N ha^(-1)a^(-1)+50 kg P ha^(-1)a^(-1)).Metagenomic sequencing characterized diversity and composition of soil microbial communities and used to construct bacterial/fungal co-occurrence networks.Nutrient-treated soils were more acidic and had higher levels of dissolved organic carbon than controls.There were no significant differences in microbial diversity and community composition across treatments.The addition of nutrients increased the abundance of copiotrophic bacteria and potentially beneficial microorganisms(e.g.,Gemmatimonadetes,Chaetomium,and Aureobasidium).Low N addition increased microbiome network connectivity.Three rare fungi were identified as module hubs under nutrient addition,indicating that low abundance fungi were more sensitive to increased nutrients.The results indicate that the overall composition of microbial communities was stable but not static to long-term N addition.Our findings provide new insights that can aid predictions of the response of soil microbial communities to long-term N addition.展开更多
Interest in the dynamics of soil respiration(R_(S))in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental changes.However,as a principal silvicult...Interest in the dynamics of soil respiration(R_(S))in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental changes.However,as a principal silvicultural practice,the long-term impacts of thinning on R_(S) and its heterotrophic and autotrophic respiration components(R_(h) and Ra,respectively)in subalpine plantations are poorly understood,espe-cially in winter.A 3-year field observation was carried out with consideration of winter CO_(2) efflux in middle-aged sub-alpine spruce plantations in northwestern China.A trench-ing method was used to explore the long-term impacts of thinning on Rs,Rn and R_(a).Seventeen years after thinning,mean annual Rs,Rn and R_(a) increased,while the contribu-tion of R_(h) to R_(s) decreased with thinning intensity.Thinning significantly decreased winter R,because of the reduction in R_(n) but had no significant effect on Ra.The temperature sensitivity(Q_(10))of R_(h) and R_(a) also increased with thinning intensity,with lower Q_(10) values for R_(h)(2.1-2.6)than for Ra(2.4-2.8).The results revealed the explanatory variables and pathways related to R_(n) and R_(a) dynamics.Thinning increased soil moisture and nitrate nitrogen(NO_(3)^(-)-N),and the enhanced nitrogen and water availability promoted R_(h) and R_(a) by improving fine root biomass and microbial activity.Our results highlight the positive roles of NO_(3)^(-)-N in stimulating R_(s) components following long-term thinning.Therefore,applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO_(2) emissions.The increased Q_(10) values of R_(s) components indicate that a large increase in soil CO_(2) emissions would be expected following thinning because of more pronounced climate warming in alpineregions.展开更多
Long-term navigation ability based on consumer-level wearable inertial sensors plays an essential role towards various emerging fields, for instance, smart healthcare, emergency rescue, soldier positioning et al. The ...Long-term navigation ability based on consumer-level wearable inertial sensors plays an essential role towards various emerging fields, for instance, smart healthcare, emergency rescue, soldier positioning et al. The performance of existing long-term navigation algorithm is limited by the cumulative error of inertial sensors, disturbed local magnetic field, and complex motion modes of the pedestrian. This paper develops a robust data and physical model dual-driven based trajectory estimation(DPDD-TE) framework, which can be applied for long-term navigation tasks. A Bi-directional Long Short-Term Memory(Bi-LSTM) based quasi-static magnetic field(QSMF) detection algorithm is developed for extracting useful magnetic observation for heading calibration, and another Bi-LSTM is adopted for walking speed estimation by considering hybrid human motion information under a specific time period. In addition, a data and physical model dual-driven based multi-source fusion model is proposed to integrate basic INS mechanization and multi-level constraint and observations for maintaining accuracy under long-term navigation tasks, and enhanced by the magnetic and trajectory features assisted loop detection algorithm. Real-world experiments indicate that the proposed DPDD-TE outperforms than existing algorithms, and final estimated heading and positioning accuracy indexes reaches 5° and less than 2 m under the time period of 30 min, respectively.展开更多
The evolution of the microstructure and tensile rupture mechanism of laser welds in UNS N10003 alloy exposed to 700℃are investigated.Fine M_(6)C carbides precipitate around the primary eutectic M_(6)C-γcarbides in t...The evolution of the microstructure and tensile rupture mechanism of laser welds in UNS N10003 alloy exposed to 700℃are investigated.Fine M_(6)C carbides precipitate around the primary eutectic M_(6)C-γcarbides in the fusion zone after 100 h of exposure.During long-term thermal exposure,the size of the fine M_(6)C carbides increased.The eutectic M_(6)C-γcarbides in the as-welded fusion zone transformed into spherical M_(6)C carbides as the exposure time extends to 10000 h.Additionally,the spherical M_(6)C particles exhibit size coarsening with increasing exposure time.The tensile properties of the welded joints are not adversely affected by the evolution of eutectic M_(6)C-γcarbides and the coarsening of M_(6)C carbides.展开更多
Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and...Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and its key controlling processes are not well understood,which limits our comprehension of the physiological mechanisms of various management practices.In this study,four forest management measures(no thinning:NT;understory removal:UR;light thinning:LT;and heavy thinning:HT)were carried out in Pinus massoniana plantations in a subtropical region of China.Photosynthetic capacity and needle stable carbon isotope composition(δ^(13)C)were measured to assess instantaneous water use efficiency(WUE_(inst))and long-term water use efficiency(WUE_(i)).Multiple regression models and structural equation modelling(SEM)identified the effects of soil properties and physiological performances on WUE_(inst)and WUE_(i).The results show that WUE_(inst)values among the four treatments were insignificant.However,compared with the NT stand(35.8μmol·mol^(-1)),WUE_(i)values significantly increased to 41.7μmol·mol^(-1)in the UR,50.1μmol·mol^(-1)in the LT and 46.6μmol·mol^(-1)in HT treatments,largely explained by photosynthetic capacity and soil water content.Understory removal did not change physiological performance(needle water potential and photosynthetic capacity).Thinning increased the net photosynthetic rate(A_n)but not stomatal conductance(g_s)or predawn needle water potential(ψ_(pd)),implying that the improvement in water use efficiency for thinned stands was largely driven by radiation interception than by soil water availability.In general,thinning may be an appropriate management measure to promote P.massoniana WUE to cope with seasonal droughts under future extreme climates.展开更多
Developing a green economy is key to achieving the 2030 Sustainable Development Goals. This paper uses the SBM-GML index, which includes non-desired outputs, to measure the trend of regional green economic efficiency ...Developing a green economy is key to achieving the 2030 Sustainable Development Goals. This paper uses the SBM-GML index, which includes non-desired outputs, to measure the trend of regional green economic efficiency changes and analyze the impact mechanism and realization path of industrial transformation on green economic efficiency. The research results show that advanced industrial structure has a positive influence on green economic efficiency nationwide, while energy utilization structure and energy utilization efficiency have positive partial intermediary effects in the influence path;industrial structure rationalization is also significantly positively related to green economic efficiency nationwide, and the mediating effect of energy utilization is positive. The impact of industrial transformation on green economic efficiency has regional heterogeneity, and the mediating effect of energy use also differs. Among them, the impact effect in the eastern region is basically consistent with the national sample, but is negative in the central and western regions. This paper proposes countermeasures in terms of adjusting the industrial structure, improving energy efficiency, and perfecting industrial and energy policies, which can provide theoretical and practical references for promoting the transformation and upgrading of regional industrial structure, optimizing energy utilization, and advancing the efficiency of the national and regional green economy.展开更多
The vertical variation and storage of nitrogen in the depth of 0-150 cm of an aquic brown soil were studied under 14 years of four land use patterns, i.e., paddy field, maize field, fallow field and woodland in Shenya...The vertical variation and storage of nitrogen in the depth of 0-150 cm of an aquic brown soil were studied under 14 years of four land use patterns, i.e., paddy field, maize field, fallow field and woodland in Shenyang Experimental Station of Ecology, Chinese Academy of Sciences in November of 2003. The results showed that different land uses had different profile distributions of soil total nitrogen (STN), alkali N, ammonium (NH4+-N) and nitrate (NO3--N). The sequence of STN storage was woodland >maize field > fallow field > paddy field, while that of NO3--N content was maize field > paddy field > woodland > fallow field, suggesting the different root biomass and biological N cycling under various land uses. The STN storage in the depth of 0-100 cm of woodland averaged to 11.41 thm-1, being 1.65 and 1.25 times as much as that in paddy and maize fields, respec-tively, while there was no significant difference between maize and fallow fields. The comparatively higher amount of NO3--N in maize and paddy fields may be due to nitrogen fertilization and anthropogenic disturbance. Soil alkali N was significantly related with STN, and the correlation could be expressed by a linear regression model under each land use (R20.929, p<0.001). Such a correlation was slightly closer in nature (woodland and fallow field) than in agro ecosystems (paddy and maize fields). Heavy N fertilization induced an excess of crop need, and led to a comparatively higher amount of soil NO3--N in cultivated fields than in fallow field and woodland. It is suggested that agroforestry practices have the potential to make a significant contribution to both crop production and environment protection.展开更多
The remote sensing （RS） and geographical information system （GIS） technologies were adopted and a mathematic method was developed to evaluate the changes of ecosystem services in the upper reaches of Minjiang Rive...The remote sensing （RS） and geographical information system （GIS） technologies were adopted and a mathematic method was developed to evaluate the changes of ecosystem services in the upper reaches of Minjiang River-valley for providing advices to manage the ecosystem. The results showed that the land use change mainly occurred on forest, farmland and grassland. From 1986 to 1994, the area of farmland increased by 477% （60801 hm^2）, while the area of forest decreased by 4.97% （89012.17 hm^2）. From 1986 to 2000, the eco-service value of forest was degressive but that of farmland increased greatly as the increasing of planting area, while the total eco-service value decreased by 771.11×10^8 yuan RMB due to the rapid increase of population in this region. The driving force of eco-service change was also discussed in the paper. The nation policy of Natural Forest Protection Project has taken effect in preventing the decline of eco-services.展开更多
Everyday Use is the best of essays written by Alice Walker,a very famous African American woman novelist.In this essay,two sisters from Africa-American family give us a deep impression.Although they are sisters,Maggie...Everyday Use is the best of essays written by Alice Walker,a very famous African American woman novelist.In this essay,two sisters from Africa-American family give us a deep impression.Although they are sisters,Maggie and Dee are different.With a concept of structuralism:binary opposition,this article shows the two sisters:Maggie and Dee have different natures,appearances and the views for the quilt.However,with their attitudes to the quilt analyzed by deconstructionism:breaking the binary opposition,the two sisters are identical:both of them regard the quilt as the rare material.Finally,this thesis points out an insufficiency of the essay.展开更多
Micrometer-sized silicon oxide(SiO)anodes encounter challenges in large-scale applications due to significant volume expansion during the alloy/de-alloy process.Herein,an innovative deep eutectic electrolyte derived f...Micrometer-sized silicon oxide(SiO)anodes encounter challenges in large-scale applications due to significant volume expansion during the alloy/de-alloy process.Herein,an innovative deep eutectic electrolyte derived from succinonitrile is introduced to enhance the cycling stability of SiO anodes.Density functional theory calculations validate a robust ion-dipole interaction between lithium ions(Li^(+))and succinonitrile(SN).The cosolvent fluoroethylene carbonate(FEC)optimizes the Li^(+)solvation structure in the SN-based electrolyte with its weakly solvating ability.Molecular dynamics simulations investigate the regulating mechanism of ion-dipole and cation-anion interaction.The unique Li^(+)solvation structure,enriched with FEC and TFSI^(-),facilitates the formation of an inorganic-organic composite solid electrolyte interphase on SiO anodes.Micro-CT further detects the inhibiting effect on the SiO volume expansion.As a result,the SiO|LiCoO_(2) full cells exhibit excellent electrochemical performance in deep eutectic-based electrolytes.This work presents an effective strategy for extending the cycle life of SiO anodes by designing a new SN-based deep eutectic electrolyte.展开更多
The address term"老师"is used widely in modem society.This paper mainly studies the general use of the address term"老师".It raised the hypothesis firstly.Then some questionnaires were handed out t...The address term"老师"is used widely in modem society.This paper mainly studies the general use of the address term"老师".It raised the hypothesis firstly.Then some questionnaires were handed out to collect the data for the analysis.According to the statistics,this phenomenon is analyzed and interpreted.It is due to both psychological and social factors.展开更多
Background:Seasonal precipitation variability significantly affects water use in forests;however,whether water uptake is adapted to changes in precipitation,particularly whether it could affect the coexistence of tree...Background:Seasonal precipitation variability significantly affects water use in forests;however,whether water uptake is adapted to changes in precipitation,particularly whether it could affect the coexistence of tree species,has rarely been quantified in forest systems.Method:In this study,dual stable isotopes and the Li-6400 portable photosynthesis system were used to determine the water sources of a mixed conifer(Pinus massoniana)and broadleaf(Quercus acutissima)forest and changes in hydraulic characteristics during the dry and wet seasons in a southern hilly region of China.Results:Although the hydraulic characteristics of P.massoniana were lower than those of Q.acutissima,it maintained a stable water source from the deep soil layer and a higher stomatal conductance(Gs),leading to a higher transpiration rate(Tr)during the growing seasons.Q.acutissima mainly absorbed water from deeper soil layers in the dry season and took up from shallow soil layers in the wet season.Its Gs values exhibited sensitivity to precipitation,while it maintained a lower Tr value during the growing seasons.The excessive water-use strategy observed in P.massoniana may confer weak drought-tolerance during higher frequency and more intense extreme precipitation events,whereas Q.acutissima may exhibit better ecological adaption to precipitation changes.Conclusions:The overlap of water niches in mixed forests did not appear to affect the coexistence of tree species.The present study provides insights into reforestation and water management in the southern hilly regions of China.展开更多
Accurate prediction of the remaining useful life(RUL)is crucial for the design and management of lithium-ion batteries.Although various machine learning models offer promising predictions,one critical but often overlo...Accurate prediction of the remaining useful life(RUL)is crucial for the design and management of lithium-ion batteries.Although various machine learning models offer promising predictions,one critical but often overlooked challenge is their demand for considerable run-to-failure data for training.Collection of such training data leads to prohibitive testing efforts as the run-to-failure tests can last for years.Here,we propose a semi-supervised representation learning method to enhance prediction accuracy by learning from data without RUL labels.Our approach builds on a sophisticated deep neural network that comprises an encoder and three decoder heads to extract time-dependent representation features from short-term battery operating data regardless of the existence of RUL labels.The approach is validated using three datasets collected from 34 batteries operating under various conditions,encompassing over 19,900 charge and discharge cycles.Our method achieves a root mean squared error(RMSE)within 25 cycles,even when only 1/50 of the training dataset is labelled,representing a reduction of 48%compared to the conventional approach.We also demonstrate the method's robustness with varying numbers of labelled data and different weights assigned to the three decoder heads.The projection of extracted features in low space reveals that our method effectively learns degradation features from unlabelled data.Our approach highlights the promise of utilising semi-supervised learning to reduce the data demand for reliability monitoring of energy devices.展开更多
In this study,using a dendrological and isotopic approaches,we investigated the responses to climate of two pure Fagus sylvatica L.stands(Campobraca and Falode)in the southernmost part of the distribution range in sou...In this study,using a dendrological and isotopic approaches,we investigated the responses to climate of two pure Fagus sylvatica L.stands(Campobraca and Falode)in the southernmost part of the distribution range in southern Italy.Theδ^(13)C data were used for calculating the intrinsic water use efficiency(iWUE)as a proxy of the balance between the water and carbon cycles.The results showed that the iWUE of both stands was sensitive to the amount of precipitation during the summer months(negative,significant effect)and to atmospheric CO_(2)concentration.Growth was sensitive to climate only in the Campo Braca site;the most influential variables were the VPD(vapour pressure deficit)and precipitation of the summer months that had a negative and a positive effect,respectively.The iWUE showed a negative correlation with growth in Campo Braca and a non-significant one in Falode.Water availability was the most influential variable on F.sylvatica growth and physiology.The iWUE increase was mainly driven by atmospheric CO_(2)concentration,and by decreased precipitation,as a response of the trees to drought.Our results highlight the importance of understanding the hydrological changes due to climate change for forecasting/modelling forest responses.CO_(2)increase does not compensate for the effect of adverse climate on F.sylvatica in the forests of southern Italy,while local conditions play an important role in determining tree growth.展开更多
Adopting corpus-based approach, the use of copular verbs by Chinese college English learners is studied through a comparison between the COLEC and the LOCNESS. The main findings are: 1)Chinese college English learners...Adopting corpus-based approach, the use of copular verbs by Chinese college English learners is studied through a comparison between the COLEC and the LOCNESS. The main findings are: 1)Chinese college English learners under-use copular verbs; 2) Chinese college English learners select a limited variety of copular verbs; 3) Types of complement after most copular verbs used by Chinese college English learners lack variety; 4) Chinese college English learners use less various and more simpler complements than native speakers.展开更多
Dee,in"Everyday Use",is portrayed as a negative character.Nevertheless,some critics suggest to re-interpret her for some reasonable causes.By using close-reading,this article try to re-evaluate Dee so to eva...Dee,in"Everyday Use",is portrayed as a negative character.Nevertheless,some critics suggest to re-interpret her for some reasonable causes.By using close-reading,this article try to re-evaluate Dee so to evalue Alice Walker’s valuable devotion in character depiction.展开更多
基金National Natural Science Foundation of China(No.51974352 and No.52288101)China University of Petroleum(East China)(No.2018000025 and No.2019000011)。
文摘The long-term strength retrogression of silica-enriched oil well cement poses a significant threat to wellbore integrity in deep and ultra-deep wells, which is a major obstacle for deep petroleum and geothermal energy development. Previous attempts to address this problem has been unsatisfactory because they can only reduce the strength decline rate. This study presents a new solution to this problem by incorporating fly ash to the traditional silica-cement systems. The influences of fly ash and silica on the strength retrogression behavior of oil well cement systems directly set and cured under the condition of 200°C and 50 MPa are investigated. Test results indicate that the slurries containing only silica or fly ash experience severe strength retrogression from 2 to 30 d curing, while the slurries containing both fly ash and silica experience strength enhancement from 2 to 90 d. The strength test results are corroborated by further evidences from permeability tests as well as microstructure analysis of set cement. Composition of set cement evaluated by quantitative X-ray diffraction analyses with partial or no known crystal structure(PONKCS) method and thermogravimetry analyses revealed that the conversion of amorphous C-(A)-S-H to crystalline phases is the primary cause of long-term strength retrogression.The addition of fly ash can reduce the initial amount of C-(A)-S-H in the set cement, and its combined use with silica can prevent the crystallization of C-(A)-S-H, which is believed to be the working mechanism of this new admixture in improving long-term strength stability of oil well cement systems.
基金funded by a Grant-in-Aid for Scientific Research(B)(Japan Society for The Promotion of Science,21H02849)Grant-in-Aid for Scientific Research(C)(Japan Society for The Promotion of Science,23K07013)+2 种基金Grant-in-Aid for Transformative Research Areas(A)(Japan Society for The Promotion of Science,JP21H05173)Grant-in-Aid by the Smoking Research FoundationGrant-in-Aid by the Telecommunications Advancement Foundation.
文摘Background Ongoing debates question the harm of internet use with the evolving technology,as many individuals transition from regular to problematic internet use(PIU).The habenula(Hb),located between the thalamus and the third ventricle,is implicated in various psychiatric disorders.In addition,personality features have been suggested to play a role in the pathophysiology of PIU.Aims This study aimed to investigate Hb volumetry in individuals with subclinical PIU and the mediating effect of personality traits on this relationship.Methods 110 healthy adults in this cross-sectional study underwent structural magnetic resonance imaging.Hb segmentation was performed using a deep learning technique.The Internet Addiction Test(IAT)and the NEO Five-Factor Inventory were used to assess the PIU level and personality,respectively.Partial Spearman's correlation analyses were performed to explore the reiationships between Hb volumetry,IAT and NEO.Multiple regression analysis was applied to identify personality traits that predict IAT scores.The significant trait was then treated as a mediator between Hb volume and IAT correlation in mediation analysis with a bootstrap value of 5000.Results Relative Hb volume was negatively correlated with IAT scores(partial rho=-0.142,p=0.009).The IAT score was positively correlated with neuroticism(partial rho=0.430,p<0.001)and negatively correlated with extraversion,agreeableness and conscientiousness(partial rho=-0.213,p<0.001;partial rho=-0.279,p<0.001;and partial rho=-0.327,p<0.001).There was a significant indirect effect of Hb volume on this model(β=-0.061,p=0.048,boot 95%confidence interval:-0.149 to-0.001).Conclusions This study uncovered a crucial link between reduced Hb volume and heightened PIU.Our findings highlight neuroticism as a key risk factor for developing PIU.Moreover,neuroticism was shown to mediate the relationship between Hb volume and PIU tendency,offering valuable insight into the complexities of this interaction.
基金supported by the National Research Foundation of Korea(NRF)(RS-2024-00333618 and RS-2023-00240999)a Korea University Grantthe Institute of Biomedical Science&Food Safety,CJ-Korea University Food Safety Hall at Korea University,Republic of Korea。
文摘This study was performed to investigate the changes in microbial communities and metabolites during the long-term fermentation of commercially manufactured anchovy sauce.Samples of commercial anchovy sauce were collected from large-scale fermentation tanks with fermentation periods of up to 7.87 years.The complex bacterial community was simplified to two genera,Tetragenococcus and Halanaerobium,after approximately 0.55 years of fermentation.Although genera,such as Saccharomyces,Cladosporium,Candida,and Aspergillus,were relatively dominant,no clear pattern was identified in fungal community analysis.The longitudinal metabolite profile demonstrated that approximately half(55.8%)of the metabolites present in anchovy sauce were produced within a year of fermentation due to rapid fermentation.Despite the static microbial community,the contents of several metabolites including amino acids and biogenic amines changed continuously during the long-term fermentation of anchovy sauce.This study provides novel insights into the changes in microbiota and metabolites in fish sauce produced without any starter inoculation.
基金the financial support from the National Natural Science Foundation of China(52207229)the financial support from the China Scholarship Council(202207550010)。
文摘The safe and reliable operation of lithium-ion batteries necessitates the accurate prediction of remaining useful life(RUL).However,this task is challenging due to the diverse ageing mechanisms,various operating conditions,and limited measured signals.Although data-driven methods are perceived as a promising solution,they ignore intrinsic battery physics,leading to compromised accuracy,low efficiency,and low interpretability.In response,this study integrates domain knowledge into deep learning to enhance the RUL prediction performance.We demonstrate accurate RUL prediction using only a single charging curve.First,a generalisable physics-based model is developed to extract ageing-correlated parameters that can describe and explain battery degradation from battery charging data.The parameters inform a deep neural network(DNN)to predict RUL with high accuracy and efficiency.The trained model is validated under 3 types of batteries working under 7 conditions,considering fully charged and partially charged cases.Using data from one cycle only,the proposed method achieves a root mean squared error(RMSE)of 11.42 cycles and a mean absolute relative error(MARE)of 3.19%on average,which are over45%and 44%lower compared to the two state-of-the-art data-driven methods,respectively.Besides its accuracy,the proposed method also outperforms existing methods in terms of efficiency,input burden,and robustness.The inherent relationship between the model parameters and the battery degradation mechanism is further revealed,substantiating the intrinsic superiority of the proposed method.
基金supported by the National Science Foundation of China(No.31770672 and 3137062)the National Basic Research Program of China(No.2010CB950602)。
文摘Atmospheric nitrogen(N)deposition is predicted to increase,especially in the subtropics.However,the responses of soil microorganisms to long-term N addition at the molecular level in N-rich subtropical forests have not been clarified.A long-term nutrient addition experiment was conducted in a subtropical evergreen old-growth forest in China.The four treatments were:control,low N(50 kg N ha^(-1)a^(-1)),high N(100 kg N ha^(-1)a^(-1)),and combined N and phosphorus(P)(100 kg N ha^(-1)a^(-1)+50 kg P ha^(-1)a^(-1)).Metagenomic sequencing characterized diversity and composition of soil microbial communities and used to construct bacterial/fungal co-occurrence networks.Nutrient-treated soils were more acidic and had higher levels of dissolved organic carbon than controls.There were no significant differences in microbial diversity and community composition across treatments.The addition of nutrients increased the abundance of copiotrophic bacteria and potentially beneficial microorganisms(e.g.,Gemmatimonadetes,Chaetomium,and Aureobasidium).Low N addition increased microbiome network connectivity.Three rare fungi were identified as module hubs under nutrient addition,indicating that low abundance fungi were more sensitive to increased nutrients.The results indicate that the overall composition of microbial communities was stable but not static to long-term N addition.Our findings provide new insights that can aid predictions of the response of soil microbial communities to long-term N addition.
基金supported by the National Natural Science Foundation of China (Grant Nos.41701296 and 42277481)the Natural Science Foundation of Gansu Province (GrantNo.22JR5RA058)the Youth Science and Technology Fund Program of Gansu Province (Grant No.22JR5RA087).
文摘Interest in the dynamics of soil respiration(R_(S))in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental changes.However,as a principal silvicultural practice,the long-term impacts of thinning on R_(S) and its heterotrophic and autotrophic respiration components(R_(h) and Ra,respectively)in subalpine plantations are poorly understood,espe-cially in winter.A 3-year field observation was carried out with consideration of winter CO_(2) efflux in middle-aged sub-alpine spruce plantations in northwestern China.A trench-ing method was used to explore the long-term impacts of thinning on Rs,Rn and R_(a).Seventeen years after thinning,mean annual Rs,Rn and R_(a) increased,while the contribu-tion of R_(h) to R_(s) decreased with thinning intensity.Thinning significantly decreased winter R,because of the reduction in R_(n) but had no significant effect on Ra.The temperature sensitivity(Q_(10))of R_(h) and R_(a) also increased with thinning intensity,with lower Q_(10) values for R_(h)(2.1-2.6)than for Ra(2.4-2.8).The results revealed the explanatory variables and pathways related to R_(n) and R_(a) dynamics.Thinning increased soil moisture and nitrate nitrogen(NO_(3)^(-)-N),and the enhanced nitrogen and water availability promoted R_(h) and R_(a) by improving fine root biomass and microbial activity.Our results highlight the positive roles of NO_(3)^(-)-N in stimulating R_(s) components following long-term thinning.Therefore,applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO_(2) emissions.The increased Q_(10) values of R_(s) components indicate that a large increase in soil CO_(2) emissions would be expected following thinning because of more pronounced climate warming in alpineregions.
文摘Long-term navigation ability based on consumer-level wearable inertial sensors plays an essential role towards various emerging fields, for instance, smart healthcare, emergency rescue, soldier positioning et al. The performance of existing long-term navigation algorithm is limited by the cumulative error of inertial sensors, disturbed local magnetic field, and complex motion modes of the pedestrian. This paper develops a robust data and physical model dual-driven based trajectory estimation(DPDD-TE) framework, which can be applied for long-term navigation tasks. A Bi-directional Long Short-Term Memory(Bi-LSTM) based quasi-static magnetic field(QSMF) detection algorithm is developed for extracting useful magnetic observation for heading calibration, and another Bi-LSTM is adopted for walking speed estimation by considering hybrid human motion information under a specific time period. In addition, a data and physical model dual-driven based multi-source fusion model is proposed to integrate basic INS mechanization and multi-level constraint and observations for maintaining accuracy under long-term navigation tasks, and enhanced by the magnetic and trajectory features assisted loop detection algorithm. Real-world experiments indicate that the proposed DPDD-TE outperforms than existing algorithms, and final estimated heading and positioning accuracy indexes reaches 5° and less than 2 m under the time period of 30 min, respectively.
基金supported by the Technology Star of Shanghai Institute of Applied Physics,Chinese Academy of Sciences(No.E2551130)the Youth Innovation Promotion Association,Chinese Academy of Sciences(No.E2292202).
文摘The evolution of the microstructure and tensile rupture mechanism of laser welds in UNS N10003 alloy exposed to 700℃are investigated.Fine M_(6)C carbides precipitate around the primary eutectic M_(6)C-γcarbides in the fusion zone after 100 h of exposure.During long-term thermal exposure,the size of the fine M_(6)C carbides increased.The eutectic M_(6)C-γcarbides in the as-welded fusion zone transformed into spherical M_(6)C carbides as the exposure time extends to 10000 h.Additionally,the spherical M_(6)C particles exhibit size coarsening with increasing exposure time.The tensile properties of the welded joints are not adversely affected by the evolution of eutectic M_(6)C-γcarbides and the coarsening of M_(6)C carbides.
基金supported by the National Key Research and Development Program of China(2016YFD0600201)the National Nonprofit Institute Research Grant of CAF(CAFYBB2017ZB003)+1 种基金the National Natural Science Foundation of China(3187071631670720)。
文摘Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and its key controlling processes are not well understood,which limits our comprehension of the physiological mechanisms of various management practices.In this study,four forest management measures(no thinning:NT;understory removal:UR;light thinning:LT;and heavy thinning:HT)were carried out in Pinus massoniana plantations in a subtropical region of China.Photosynthetic capacity and needle stable carbon isotope composition(δ^(13)C)were measured to assess instantaneous water use efficiency(WUE_(inst))and long-term water use efficiency(WUE_(i)).Multiple regression models and structural equation modelling(SEM)identified the effects of soil properties and physiological performances on WUE_(inst)and WUE_(i).The results show that WUE_(inst)values among the four treatments were insignificant.However,compared with the NT stand(35.8μmol·mol^(-1)),WUE_(i)values significantly increased to 41.7μmol·mol^(-1)in the UR,50.1μmol·mol^(-1)in the LT and 46.6μmol·mol^(-1)in HT treatments,largely explained by photosynthetic capacity and soil water content.Understory removal did not change physiological performance(needle water potential and photosynthetic capacity).Thinning increased the net photosynthetic rate(A_n)but not stomatal conductance(g_s)or predawn needle water potential(ψ_(pd)),implying that the improvement in water use efficiency for thinned stands was largely driven by radiation interception than by soil water availability.In general,thinning may be an appropriate management measure to promote P.massoniana WUE to cope with seasonal droughts under future extreme climates.
基金supported by National Natural Science Foundation of China [grant numbers 42371194]。
文摘Developing a green economy is key to achieving the 2030 Sustainable Development Goals. This paper uses the SBM-GML index, which includes non-desired outputs, to measure the trend of regional green economic efficiency changes and analyze the impact mechanism and realization path of industrial transformation on green economic efficiency. The research results show that advanced industrial structure has a positive influence on green economic efficiency nationwide, while energy utilization structure and energy utilization efficiency have positive partial intermediary effects in the influence path;industrial structure rationalization is also significantly positively related to green economic efficiency nationwide, and the mediating effect of energy utilization is positive. The impact of industrial transformation on green economic efficiency has regional heterogeneity, and the mediating effect of energy use also differs. Among them, the impact effect in the eastern region is basically consistent with the national sample, but is negative in the central and western regions. This paper proposes countermeasures in terms of adjusting the industrial structure, improving energy efficiency, and perfecting industrial and energy policies, which can provide theoretical and practical references for promoting the transformation and upgrading of regional industrial structure, optimizing energy utilization, and advancing the efficiency of the national and regional green economy.
文摘The vertical variation and storage of nitrogen in the depth of 0-150 cm of an aquic brown soil were studied under 14 years of four land use patterns, i.e., paddy field, maize field, fallow field and woodland in Shenyang Experimental Station of Ecology, Chinese Academy of Sciences in November of 2003. The results showed that different land uses had different profile distributions of soil total nitrogen (STN), alkali N, ammonium (NH4+-N) and nitrate (NO3--N). The sequence of STN storage was woodland >maize field > fallow field > paddy field, while that of NO3--N content was maize field > paddy field > woodland > fallow field, suggesting the different root biomass and biological N cycling under various land uses. The STN storage in the depth of 0-100 cm of woodland averaged to 11.41 thm-1, being 1.65 and 1.25 times as much as that in paddy and maize fields, respec-tively, while there was no significant difference between maize and fallow fields. The comparatively higher amount of NO3--N in maize and paddy fields may be due to nitrogen fertilization and anthropogenic disturbance. Soil alkali N was significantly related with STN, and the correlation could be expressed by a linear regression model under each land use (R20.929, p<0.001). Such a correlation was slightly closer in nature (woodland and fallow field) than in agro ecosystems (paddy and maize fields). Heavy N fertilization induced an excess of crop need, and led to a comparatively higher amount of soil NO3--N in cultivated fields than in fallow field and woodland. It is suggested that agroforestry practices have the potential to make a significant contribution to both crop production and environment protection.
基金This study was supported and funded by the projects of NKBRSF, P.R. China (No. 2002CB111506)
文摘The remote sensing （RS） and geographical information system （GIS） technologies were adopted and a mathematic method was developed to evaluate the changes of ecosystem services in the upper reaches of Minjiang River-valley for providing advices to manage the ecosystem. The results showed that the land use change mainly occurred on forest, farmland and grassland. From 1986 to 1994, the area of farmland increased by 477% （60801 hm^2）, while the area of forest decreased by 4.97% （89012.17 hm^2）. From 1986 to 2000, the eco-service value of forest was degressive but that of farmland increased greatly as the increasing of planting area, while the total eco-service value decreased by 771.11×10^8 yuan RMB due to the rapid increase of population in this region. The driving force of eco-service change was also discussed in the paper. The nation policy of Natural Forest Protection Project has taken effect in preventing the decline of eco-services.
文摘Everyday Use is the best of essays written by Alice Walker,a very famous African American woman novelist.In this essay,two sisters from Africa-American family give us a deep impression.Although they are sisters,Maggie and Dee are different.With a concept of structuralism:binary opposition,this article shows the two sisters:Maggie and Dee have different natures,appearances and the views for the quilt.However,with their attitudes to the quilt analyzed by deconstructionism:breaking the binary opposition,the two sisters are identical:both of them regard the quilt as the rare material.Finally,this thesis points out an insufficiency of the essay.
基金supported by the National Natural Science Foundation of China(22279026)the National Key Research and Development Program of China(2022YFE0138900)+2 种基金the Young Elite Scientist sponsorship program by CAST(no.20200148)the Natural Science Funds of Heilongjiang Province(YQ2021B003)the Fundamental Research Funds for the Central Universities(grant no.HIT.OCEF.2022017).
文摘Micrometer-sized silicon oxide(SiO)anodes encounter challenges in large-scale applications due to significant volume expansion during the alloy/de-alloy process.Herein,an innovative deep eutectic electrolyte derived from succinonitrile is introduced to enhance the cycling stability of SiO anodes.Density functional theory calculations validate a robust ion-dipole interaction between lithium ions(Li^(+))and succinonitrile(SN).The cosolvent fluoroethylene carbonate(FEC)optimizes the Li^(+)solvation structure in the SN-based electrolyte with its weakly solvating ability.Molecular dynamics simulations investigate the regulating mechanism of ion-dipole and cation-anion interaction.The unique Li^(+)solvation structure,enriched with FEC and TFSI^(-),facilitates the formation of an inorganic-organic composite solid electrolyte interphase on SiO anodes.Micro-CT further detects the inhibiting effect on the SiO volume expansion.As a result,the SiO|LiCoO_(2) full cells exhibit excellent electrochemical performance in deep eutectic-based electrolytes.This work presents an effective strategy for extending the cycle life of SiO anodes by designing a new SN-based deep eutectic electrolyte.
文摘The address term"老师"is used widely in modem society.This paper mainly studies the general use of the address term"老师".It raised the hypothesis firstly.Then some questionnaires were handed out to collect the data for the analysis.According to the statistics,this phenomenon is analyzed and interpreted.It is due to both psychological and social factors.
基金supported by the National Natural Science Foundation of China(No.42377068)Jiangsu Provincial Natural Science Foundation(No.BK20231290)Yinshanbeilu Grassland Eco-hydrology National Observation and Research Station(China Institute of Water Resources and Hydropower Research,No.YSS2022003)the Qing Lan Project。
文摘Background:Seasonal precipitation variability significantly affects water use in forests;however,whether water uptake is adapted to changes in precipitation,particularly whether it could affect the coexistence of tree species,has rarely been quantified in forest systems.Method:In this study,dual stable isotopes and the Li-6400 portable photosynthesis system were used to determine the water sources of a mixed conifer(Pinus massoniana)and broadleaf(Quercus acutissima)forest and changes in hydraulic characteristics during the dry and wet seasons in a southern hilly region of China.Results:Although the hydraulic characteristics of P.massoniana were lower than those of Q.acutissima,it maintained a stable water source from the deep soil layer and a higher stomatal conductance(Gs),leading to a higher transpiration rate(Tr)during the growing seasons.Q.acutissima mainly absorbed water from deeper soil layers in the dry season and took up from shallow soil layers in the wet season.Its Gs values exhibited sensitivity to precipitation,while it maintained a lower Tr value during the growing seasons.The excessive water-use strategy observed in P.massoniana may confer weak drought-tolerance during higher frequency and more intense extreme precipitation events,whereas Q.acutissima may exhibit better ecological adaption to precipitation changes.Conclusions:The overlap of water niches in mixed forests did not appear to affect the coexistence of tree species.The present study provides insights into reforestation and water management in the southern hilly regions of China.
基金supported by the National Natural Science Foundation of China(No.52207229)the Key Research and Development Program of Ningxia Hui Autonomous Region of China(No.2024BEE02003)+1 种基金the financial support from the AEGiS Research Grant 2024,University of Wollongong(No.R6254)the financial support from the China Scholarship Council(No.202207550010).
文摘Accurate prediction of the remaining useful life(RUL)is crucial for the design and management of lithium-ion batteries.Although various machine learning models offer promising predictions,one critical but often overlooked challenge is their demand for considerable run-to-failure data for training.Collection of such training data leads to prohibitive testing efforts as the run-to-failure tests can last for years.Here,we propose a semi-supervised representation learning method to enhance prediction accuracy by learning from data without RUL labels.Our approach builds on a sophisticated deep neural network that comprises an encoder and three decoder heads to extract time-dependent representation features from short-term battery operating data regardless of the existence of RUL labels.The approach is validated using three datasets collected from 34 batteries operating under various conditions,encompassing over 19,900 charge and discharge cycles.Our method achieves a root mean squared error(RMSE)within 25 cycles,even when only 1/50 of the training dataset is labelled,representing a reduction of 48%compared to the conventional approach.We also demonstrate the method's robustness with varying numbers of labelled data and different weights assigned to the three decoder heads.The projection of extracted features in low space reveals that our method effectively learns degradation features from unlabelled data.Our approach highlights the promise of utilising semi-supervised learning to reduce the data demand for reliability monitoring of energy devices.
基金partially supported by MIUR Project (PRIN 2020) "Unravelling interactions between WATER and carbon cycles during drought and their impact on water resources and forest and grassland ecosySTEMs in the Mediterranean climate (WATERSTEM)" (protocol code:20202WF53Z)"WAFER" at CNR (Consiglio Nazionale delle Ricerche)MIUR Project (PRIN 2017) "The Italian TREETALKER NETWORK:continuous large scale monitoring of tree functional traits and vulnerabilities to climate change"
文摘In this study,using a dendrological and isotopic approaches,we investigated the responses to climate of two pure Fagus sylvatica L.stands(Campobraca and Falode)in the southernmost part of the distribution range in southern Italy.Theδ^(13)C data were used for calculating the intrinsic water use efficiency(iWUE)as a proxy of the balance between the water and carbon cycles.The results showed that the iWUE of both stands was sensitive to the amount of precipitation during the summer months(negative,significant effect)and to atmospheric CO_(2)concentration.Growth was sensitive to climate only in the Campo Braca site;the most influential variables were the VPD(vapour pressure deficit)and precipitation of the summer months that had a negative and a positive effect,respectively.The iWUE showed a negative correlation with growth in Campo Braca and a non-significant one in Falode.Water availability was the most influential variable on F.sylvatica growth and physiology.The iWUE increase was mainly driven by atmospheric CO_(2)concentration,and by decreased precipitation,as a response of the trees to drought.Our results highlight the importance of understanding the hydrological changes due to climate change for forecasting/modelling forest responses.CO_(2)increase does not compensate for the effect of adverse climate on F.sylvatica in the forests of southern Italy,while local conditions play an important role in determining tree growth.
文摘Adopting corpus-based approach, the use of copular verbs by Chinese college English learners is studied through a comparison between the COLEC and the LOCNESS. The main findings are: 1)Chinese college English learners under-use copular verbs; 2) Chinese college English learners select a limited variety of copular verbs; 3) Types of complement after most copular verbs used by Chinese college English learners lack variety; 4) Chinese college English learners use less various and more simpler complements than native speakers.
文摘Dee,in"Everyday Use",is portrayed as a negative character.Nevertheless,some critics suggest to re-interpret her for some reasonable causes.By using close-reading,this article try to re-evaluate Dee so to evalue Alice Walker’s valuable devotion in character depiction.
