期刊文献+
共找到594篇文章
< 1 2 30 >
每页显示 20 50 100
Nicotinic Acid Activated Cp_(2)TiCl_(2) for Synergistic Catalysis of C-H Functionalization to Synthesize 2-(N-substituted amino)-1,4-Naphthoquinones
1
作者 WANG Yunyun MA Caixia WANG Tao 《分子催化(中英文)》 北大核心 2025年第5期472-482,I0005,共12页
Cp_(2)TiCl_(2) as a Lewis acid precursor and nicotinic acid as a ligand have been used synergistically for the one-pot synthesis of 2-(N-substituted amino)-1,4-naphthoquinones.This method establishes a general strateg... Cp_(2)TiCl_(2) as a Lewis acid precursor and nicotinic acid as a ligand have been used synergistically for the one-pot synthesis of 2-(N-substituted amino)-1,4-naphthoquinones.This method establishes a general strategy for the functionalization and conversion of C-H bonds of 1,4-naphthoquinones into C-N bonds,providing an effective route to synthesize 2-(N-substituted amino)-1,4-naphthoquinone with high yield under mild conditions.Additionally,the synergistic catalytic mechanism was investigated by 1H NMR titration experiments and LC-MS analysis,with experimental results sufficiently and consistently supporting the proposed mechanism of the catalytic cycle. 展开更多
关键词 C-H functionalization 2-(N-substituted amino)-1 4-naphthoquinone Cp_(2)TiCl_(2) synergistic catalysis
在线阅读 下载PDF
Laser surface functionalization to achieve extreme surface wetting conditions and resultant surface functionalities 被引量:6
2
作者 WANG Qing-hua WANG Hui-xin 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第10期3217-3247,共31页
Wetting condition of micro/nanostructured surface has received tremendous attention due to the potential applications in commercial,industrial,and military areas.Surfaces with extreme wetting properties,e.g.,superhydr... Wetting condition of micro/nanostructured surface has received tremendous attention due to the potential applications in commercial,industrial,and military areas.Surfaces with extreme wetting properties,e.g.,superhydrophobic or superhydrophilic,are extensively employed due to their superior anti-icing,drag reduction,enhanced boiling heat transfer,self-cleaning,and anti-bacterial properties depending on solid-liquid interfacial interactions.Laser-based techniques have gained popularity in recent years to create micro/nano-structured surface owing to their high flexibility,system precision,and ease for automation.These techniques create laser induced periodic surface structures(LIPSS)or hierarchical structures on substrate material.However,micro/nanostructures alone cannot attain the desired wettability.Subsequent modification of surface chemistry is essentially needed to achieve target extreme wettability.This review paper aims to provide a comprehensive review for both laser texturing techniques and the following chemistry modification methods.Recent research progress and fundamental mechanisms of surface structure generation via different types of lasers and various chemistry modification methods are discussed.The complex combination between the laser texturing and surface chemistry modification methods to decide the final wetting condition is presented.More importantly,surface functionalities of these surfaces with extreme wetting properties are discussed.Lastly,prospects for future research are proposed and discussed. 展开更多
关键词 laser surface modification extreme wettability chemistry modification surface functionality
在线阅读 下载PDF
The use of an oxidized carbon nanotube film to control Zn deposition and eliminate dendrite formation in a Zn ion battery
3
作者 LI Pin-xiang YI Zhe-han +3 位作者 WANG Ye-xing HE Chang LIANG Ji HOU Feng 《新型炭材料(中英文)》 北大核心 2025年第1期154-166,共13页
Aqueous zinc ion batteries are regarded as one of the most promising candidates for large-scale energy stor-age due to their high safety,cost-effectiveness,and environ-mental friendliness.However,uncontrolled zinc den... Aqueous zinc ion batteries are regarded as one of the most promising candidates for large-scale energy stor-age due to their high safety,cost-effectiveness,and environ-mental friendliness.However,uncontrolled zinc dendrite growth and side reactions of the zinc anode decrease the sta-bility of Zn batteries.We report the synthesis of an air-oxid-ized carbon nanotube(O-CNT)film by chemical vapor de-position followed by heat treatment in air which is used as a protective layer on the Zn foil to suppress zinc dendrite growth.The increase in the hydrophilicity of the O-CNT film caused by air oxidation facilitates zinc deposition between the film and the anode instead of deposition on the film surface.The porous structure of the O-CNT film homogenizes the Zn^(2+)ion flux and the electric field on the surface of the Zn foil,leading to the uniform deposition of Zn.As a result,a O-CNT@Zn symmetric cell has a much better cycling stability with a life of more than 3000 h at 1 mA cm^(−2) with a capacity of 1 mAh cm^(−2),and values of more than 2000 h and 1 mAh cm^(−2) at 5 mA cm^(−2).In addition,a O-CNT@Zn||Mn^(2+)inserted hydrated vanadium pentoxide(MnVOH)full cell has a better rate per-formance than a Zn||MnVOH cell,achieving a high discharge capacity of 194 mAh g^(−1) at a high current density of 8 A g^(−1).In a long-term cycling test,the O-CNT@Zn||MnVOH full cell has a capacity retention of 58.8%after 2000 cycles at a current density of 5 A·g^(−1). 展开更多
关键词 Carbon nanotubes Zn metal anodes Dendrite-free HYDROPHILIC Surface functionalization
在线阅读 下载PDF
Laser-based fabrication of superhydrophobic glass with high transparency and robustness
4
作者 LIU Chao WANG Qing-hua +4 位作者 GE Zhi-qiang LI Hao-yu FU Jia-jun WANG Hui-xin ZHANG Tai-rui 《Journal of Central South University》 2025年第1期160-173,共14页
Superhydrophobic glass has inspiring development prospects in endoscopes,solar panels and other engineering and medical fields.However,the surface topography required to achieve superhydrophobicity will inevitably aff... Superhydrophobic glass has inspiring development prospects in endoscopes,solar panels and other engineering and medical fields.However,the surface topography required to achieve superhydrophobicity will inevitably affect the surface transparency and limit the application of glass materials.To resolve the contradiction between the surface transparency and the robust superhydrophobicity,an efficient and low-cost laser-chemical surface functionalization process was utilized to fabricate superhydrophobic glass surface.The results show that the air can be effectively trapped in surface micro/nanostructure induced by laser texturing,thus reducing the solid-liquid contact area and interfacial tension.The deposition of hydrophobic carbon-containing groups on the surface can be accelerated by chemical treatment,and the surface energy is significantly reduced.The glass surface exhibits marvelous robust superhydrophobicity with a contact angle of 155.8°and a roll-off angle of 7.2°under the combination of hierarchical micro/nanostructure and low surface energy.Moreover,the surface transparency of the prepared superhydrophobic glass was only 5.42%lower than that of the untreated surface.This superhydrophobic glass with high transparency still maintains excellent superhydrophobicity after durability and stability tests.The facile fabrication of superhydrophobic glass with high transparency and robustness provides a strong reference for further expanding the application value of glass materials. 展开更多
关键词 superhydrophobic glass laser-chemical functionalization TRANSPARENCY ROBUSTNESS highly efficient
在线阅读 下载PDF
Complexation and Fluorescence Enhancement of Bay-site Carboxyl Modified Perylene Dimide with Calcium Ion 被引量:2
5
作者 GU Dandan ZHAO Haoru +4 位作者 JIANG Xiaoze QI Haohan LIAO Zuogui CHEN Jia SUN Bin 《发光学报》 北大核心 2025年第3期474-485,共12页
Bay-site carboxyl functionalized perylene diimide derivative 1,7-COOH-PDI-C_(12)(PDI-COOH)was synthesized and distinct enhanced fluorescence was observed through combining with calcium ion(Ca^(2+))in THF/H_(2)O soluti... Bay-site carboxyl functionalized perylene diimide derivative 1,7-COOH-PDI-C_(12)(PDI-COOH)was synthesized and distinct enhanced fluorescence was observed through combining with calcium ion(Ca^(2+))in THF/H_(2)O solution.The assembly and fluorescence behavior of PDI-COOH/Ca^(2+)were studied in detail by changing hydration state with different concentrations.Based on the differences in assembly morphology and stoichiometric ratios of PDICOOH/Ca^(2+),we proposed the fluorescence emission mechanism of PDI-COOH/Ca^(2+)in THF/H_(2)O and THF,respectively.This work reveals a novel strategy of aggregated state fluorescence enhancement and reminds us of the important role of water in molecular fluorescence emission and assembly. 展开更多
关键词 carboxyl functionalized fluorescence behavior perylene diimide photoinduced electron transfer effect calcium ion
在线阅读 下载PDF
Normalized Solutions of Nonlinear Choquard Equations with Nonconstant Potential
6
作者 LI Nan XU Liping 《应用数学》 北大核心 2025年第1期14-29,共16页
In this paper,we mainly focus on a type of nonlinear Choquard equations with nonconstant potential.Under appropriate hypotheses on potential function and nonlinear terms,we prove that the above Choquard equation with ... In this paper,we mainly focus on a type of nonlinear Choquard equations with nonconstant potential.Under appropriate hypotheses on potential function and nonlinear terms,we prove that the above Choquard equation with prescribed 2-norm has some normalized solutions by introducing variational methods. 展开更多
关键词 Nonlinear Choquard equation Potential function Variational method Normalized solution
在线阅读 下载PDF
Construction of Even-Variable 2-Output Almost Optimal Five-Valued Spectra Boolean Functions
7
作者 SONG Chao-Fan JI Yan-Han SUN Yu-Juan 《密码学报(中英文)》 北大核心 2025年第3期714-728,共15页
Five-valued Boolean functions play an important role in the design of symmetric cryptography.While the design and properties of single-output almost optimal five-valued spectra Boolean functions have been extensively ... Five-valued Boolean functions play an important role in the design of symmetric cryptography.While the design and properties of single-output almost optimal five-valued spectra Boolean functions have been extensively studied over the past few decades,there has been limited research on the construction of almost optimal five-valued spectra vectorial Boolean functions.In this paper,we present a construction method for even-variable 2-output almost optimal five-valued spectra balanced Boolean functions,whose Walsh spectra values belong to the set{0,±2^(n/2),±2^(n/2+1)},at the same time,we discuss the existence of sufficient conditions in the construction.Additionally,this paper presents a novel construction method for balanced single-output Boolean functions with even variables featuring a special five-valued spectral structure,whose Walsh spectra values are constrained to the set{0,±2^(n/2),±3·2^(n/2)}.These functions provide new canonical examples for the study of Boolean function spectral theory. 展开更多
关键词 Boolean function Walsh transform semi-bent function five-valued function totally disjoint spectra functions
在线阅读 下载PDF
An Approximation Method for Singular Trudinger-Moser Inequality
8
作者 ZHU Maochun XU Wenyan JIANG Rou 《应用数学》 北大核心 2025年第1期64-70,共7页
In this paper,we construct a power type functional which is the approximation functional of the Singular Trudinger-Moser functional.Moreover,we obtain the concentration level of the functional and show it converges to... In this paper,we construct a power type functional which is the approximation functional of the Singular Trudinger-Moser functional.Moreover,we obtain the concentration level of the functional and show it converges to the concentration level of singular Trudinger-Moser functional on the unit ball. 展开更多
关键词 Singular Trudinger-Moser inequality Approximation functional Concentration level
在线阅读 下载PDF
Molecular simulation study of the microstructures and properties of pyridinium ionic liquid[HPy][BF_(4)]mixed with acetonitrile
9
作者 XU Jian-Qiang MA Zhao-Peng +2 位作者 CHENG Si LIU Zhi-Cong ZHU Guang-Lai 《原子与分子物理学报》 CAS 北大核心 2025年第4期27-32,共6页
The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this wo... The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this work.The following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution function.The results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient decreases.Additionally,the excess molar volume initially decreases,reaches a minimum,and then increases.The rules of radial distribution functions(RDFs)of characteristic atoms are different.With increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then decreases.This indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently. 展开更多
关键词 Pyridinium ionic liquids Thermodynamic properties Molecular dynamics simulation Radial distribution functions
在线阅读 下载PDF
Effects of Ultrasound-Assisted Alkaline Extraction on the Structural and Emulsifying Properties of Chickpea Protein Isolate
10
作者 ZHANG Yixue YANG Qing +4 位作者 CHENG Teng ZHENG Ruihan MA Wuchao HE Xiangli LI Ke 《食品科学》 北大核心 2025年第19期236-247,共12页
This study aimed to investigate the effect of ultrasound-assisted alkaline extraction(UAE)(at 20 kHz and different powers of 0,200,300,400,500 and 600 W for 10 min)on the yield,structure and emulsifying properties of ... This study aimed to investigate the effect of ultrasound-assisted alkaline extraction(UAE)(at 20 kHz and different powers of 0,200,300,400,500 and 600 W for 10 min)on the yield,structure and emulsifying properties of chickpea protein isolate(CPI).Compared with the non-ultrasound group,ultrasound treatment at 400 W resulted in the largest increase in CPI yield,and both the particle size and turbidity decreased with increasing ultrasound power from 0 to 400 W.The scanning electron microscope results showed a uniform structural distribution of CPI.Moreover,itsα-helix content increased,β-sheet content decreased,and total sulfhydryl group content and endogenous fluorescence intensity rose,illustrating that UAE changed the secondary and tertiary structure of CPI.At 400 W,the solubility of the emulsion increased to 63.18%,and the best emulsifying properties were obtained;the emulsifying activity index(EAI)and emulsifying stability index(ESI)increased by 85.42%and 46.78%,respectively.Furthermore,the emulsion droplets formed were smaller and more uniform.In conclusion,proper UAE power conditions increased the extraction yield and protein content of CPI,and effectively improved its structure and emulsifying characteristics. 展开更多
关键词 CHICKPEA ULTRASOUND extraction yield protein structure functional properties
在线阅读 下载PDF
Design of Underground Load Haul Dump Hybrid Power System Based on QFD and TRIZ
11
作者 XU Jun QIAO Sha +3 位作者 MA Xiaowen YUAN Kun QI Wenbo LIU Keyi 《有色金属(中英文)》 北大核心 2025年第3期462-473,共12页
As the mining industry continues to expand and international oil prices increase,more rigorous demands are being placed on the design of mining equipment.Given this,there is an urgent need to develop new power-driven ... As the mining industry continues to expand and international oil prices increase,more rigorous demands are being placed on the design of mining equipment.Given this,there is an urgent need to develop new power-driven mining equipment to solve the problems of high energy consumption and insufficient power coupling of current equipment.This study proposed a design of a hybrid power system for underground Load Haul Dump(LHD).The proposed design integrated Quality Function Deployment(QFD)and Theory of Inventive Problem Solving(TRIZ).It identified 7 user requirements and 10 related technical features,formulated 11 innovative design solutions,and ultimately adopting an electric drive hybrid power scheme.This scheme effectively addressesd power transmission coupling problems and improve the efficiency of loaders.A 6 m³hybrid power loader prototype has been developed,which reduces operational energy consumption and advances the electrification and green,low-carbon evolution of mining equipment. 展开更多
关键词 quality function deployment TRIZ LHD design solution
在线阅读 下载PDF
DnCNN-RM:an adaptive SAR image denoising algorithm based on residual networks
12
作者 OU Hai-ning LI Chang-di +3 位作者 ZENG Rui-bin WU Yan-feng LIU Jia-ning CHENG Peng 《中国光学(中英文)》 北大核心 2025年第5期1209-1218,共10页
In the field of image processing,the analysis of Synthetic Aperture Radar(SAR)images is crucial due to its broad range of applications.However,SAR images are often affected by coherent speckle noise,which significantl... In the field of image processing,the analysis of Synthetic Aperture Radar(SAR)images is crucial due to its broad range of applications.However,SAR images are often affected by coherent speckle noise,which significantly degrades image quality.Traditional denoising methods,typically based on filter techniques,often face challenges related to inefficiency and limited adaptability.To address these limitations,this study proposes a novel SAR image denoising algorithm based on an enhanced residual network architecture,with the objective of enhancing the utility of SAR imagery in complex electromagnetic environments.The proposed algorithm integrates residual network modules,which directly process the noisy input images to generate denoised outputs.This approach not only reduces computational complexity but also mitigates the difficulties associated with model training.By combining the Transformer module with the residual block,the algorithm enhances the network's ability to extract global features,offering superior feature extraction capabilities compared to CNN-based residual modules.Additionally,the algorithm employs the adaptive activation function Meta-ACON,which dynamically adjusts the activation patterns of neurons,thereby improving the network's feature extraction efficiency.The effectiveness of the proposed denoising method is empirically validated using real SAR images from the RSOD dataset.The proposed algorithm exhibits remarkable performance in terms of EPI,SSIM,and ENL,while achieving a substantial enhancement in PSNR when compared to traditional and deep learning-based algorithms.The PSNR performance is enhanced by over twofold.Moreover,the evaluation of the MSTAR SAR dataset substantiates the algorithm's robustness and applicability in SAR denoising tasks,with a PSNR of 25.2021 being attained.These findings underscore the efficacy of the proposed algorithm in mitigating speckle noise while preserving critical features in SAR imagery,thereby enhancing its quality and usability in practical scenarios. 展开更多
关键词 SAR images image denoising residual networks adaptive activation function
在线阅读 下载PDF
Public-Key Function-Private Inner-Product Predicate Encryption from Pairings
13
作者 WAN Ming WANG Geng GU Da-Wu 《密码学报(中英文)》 北大核心 2025年第1期227-246,共20页
This study constructs a function-private inner-product predicate encryption(FP-IPPE)and achieves standard enhanced function privacy.The enhanced function privacy guarantees that a predicate secret key skf reveals noth... This study constructs a function-private inner-product predicate encryption(FP-IPPE)and achieves standard enhanced function privacy.The enhanced function privacy guarantees that a predicate secret key skf reveals nothing about the predicate f,as long as f is drawn from an evasive distribution with sufficient entropy.The proposed scheme extends the group-based public-key function-private predicate encryption(FP-PE)for“small superset predicates”proposed by Bartusek et al.(Asiacrypt 19),to the setting of inner-product predicates.This is the first construction of public-key FP-PE with enhanced function privacy security beyond the equality predicates,which is previously proposed by Boneh et al.(CRYPTO 13).The proposed construction relies on bilinear groups,and the security is proved in the generic bilinear group model. 展开更多
关键词 predicate encryption function privacy inner product generic group model
在线阅读 下载PDF
Multi-objective parameter optimization of abrasive water jet polishing for fused silica
14
作者 LI Qian YAO Peng +6 位作者 DENG Hong-xing FENG Chen-yu XU Chong-hai QU Shuo-shuo YANG Yu-ying ZHU Hong-tao HUANG Chuan-zhen 《中国光学(中英文)》 北大核心 2025年第5期1185-1199,共15页
As a non-contact ultra-precision machining method,abrasive water jet polishing(AWJP)has signi-ficant application in optical elements processing due to its stable tool influence function(TIF),no subsurface damage and s... As a non-contact ultra-precision machining method,abrasive water jet polishing(AWJP)has signi-ficant application in optical elements processing due to its stable tool influence function(TIF),no subsurface damage and strong adaptability to workpiece shapes.In this study,the effects of jet pressure,nozzle diameter and impinging angle on the distribution of pressure,velocity and wall shear stress in the polishing flow field were systematically analyzed by computational fluid dynamics(CFD)simulation.Based on the Box-Behnken experimental design,a response surface regression model was constructed to investigate the influence mech-anism of process parameters on material removal rate(MRR)and surface roughness(Ra)of fused silica.And experimental results showed that increasing jet pressure and nozzle diameter significantly improved MRR,consistent with shear stress distribution revealed by CFD simulations.However,increasing jet pressure and impinging angle caused higher Ra values,which was unfavorable for surface quality improvement.Genetic algorithm(GA)was used for multi-objective optimization to establish Pareto solutions,achieving concurrent optimization of polishing efficiency and surface quality.A parameter combination of 2 MPa jet pressure,0.3 mm nozzle diameter,and 30°impinging angle achieved MRR of 169.05μm^(3)/s and Ra of 0.50 nm.Exper-imental verification showed prediction errors of 4.4%(MRR)and 3.8%(Ra),confirming the model’s reliabil-ity.This parameter optimization system provides theoretical basis and technical support for ultra-precision polishing of complex curved optical components. 展开更多
关键词 ABRASIVE computational fluid dynamics tool influence function material removal rate surface roughness
在线阅读 下载PDF
rTMS Improves Cognitive Function and Brain Network Connectivity in Patients With Alzheimer’s Disease
15
作者 XU Gui-Zhi LIU Lin +4 位作者 GUO Miao-Miao WANG Tian GAO Jiao-Jiao JI Yong WANG Pan 《生物化学与生物物理进展》 北大核心 2025年第8期2131-2145,共15页
Objective Repetitive transcranial magnetic stimulation(rTMS)has demonstrated efficacy in enhancing neurocognitive performance in Alzheimer’s disease(AD),but the neurobiological mechanisms linking synaptic pathology,n... Objective Repetitive transcranial magnetic stimulation(rTMS)has demonstrated efficacy in enhancing neurocognitive performance in Alzheimer’s disease(AD),but the neurobiological mechanisms linking synaptic pathology,neural oscillatory dynamics,and brain network reorganization remain unclear.This investigation seeks to systematically evaluate the therapeutic potential of rTMS as a non-invasive neuromodulatory intervention through a multimodal framework integrating clinical assessments,molecular profiling,and neurophysiological monitoring.Methods In this prospective double-blind trial,12 AD patients underwent a 14-day protocol of 20 Hz rTMS,with comprehensive multimodal assessments performed pre-and postintervention.Cognitive functioning was quantified using the mini-mental state examination(MMSE)and Montreal cognitive assessment(MOCA),while daily living capacities and neuropsychiatric profiles were respectively evaluated through the activities of daily living(ADL)scale and combined neuropsychiatric inventory(NPI)-Hamilton depression rating scale(HAMD).Peripheral blood biomarkers,specifically Aβ1-40 and phosphorylated tau(p-tau181),were analyzed to investigate the effects of rTMS on molecular metabolism.Spectral power analysis was employed to investigate rTMS-induced modulations of neural rhythms in AD patients,while brain network analyses incorporating topological properties were conducted to examine stimulus-driven network reorganization.Furthermore,systematic assessment of correlations between cognitive scale scores,blood biomarkers,and network characteristics was performed to elucidate cross-modal therapeutic associations.Results Clinically,MMSE and MOCA scores improved significantly(P<0.05).Biomarker showed that Aβ1-40 level increased(P<0.05),contrasting with p-tau181 reduction.Moreover,the levels of Aβ1-40 were positively correlated with MMSE and MOCA scores.Post-intervention analyses revealed significant modulations in oscillatory power,characterized by pronounced reductions in delta(P<0.05)and theta bands(P<0.05),while concurrent enhancements were observed in alpha,beta,and gamma band activities(all P<0.05).Network analysis revealed frequency-specific reorganization:clustering coefficients were significantly decreased in delta,theta,and alpha bands(P<0.05),while global efficiency improvement was exclusively detected in the delta band(P<0.05).The alpha band demonstrated concurrent increases in average nodal degree(P<0.05)and characteristic path length reduction(P<0.05).Further research findings indicate that the changes in the clinical scale HAMD scores before and after rTMS stimulation are negatively correlated with the changes in the blood biomarkers Aβ1-40 and p-tau181.Additionally,the changes in the clinical scales MMSE and MoCA scores were negatively correlated with the changes in the node degree of the alpha frequency band and negatively correlated with the clustering coefficient of the delta frequency band.However,the changes in MMSE scores are positively correlated with the changes in global efficiency of both the delta and alpha frequency bands.Conclusion 20 Hz rTMS targeting dorsolateral prefrontal cortex(DLPFC)significantly improves cognitive function and enhances the metabolic clearance ofβ-amyloid and tau proteins in AD patients.This neurotherapeutic effect is mechanistically associated with rTMS-mediated frequency-selective neuromodulation,which enhances the connectivity of oscillatory networks through improved neuronal synchronization and optimized topological organization of functional brain networks.These findings not only support the efficacy of rTMS as an adjunctive therapy for AD but also underscore the importance of employing multiple assessment methods—including clinical scales,blood biomarkers,and EEG——in understanding and monitoring the progression of AD.This research provides a significant theoretical foundation and empirical evidence for further exploration of rTMS applications in AD treatment. 展开更多
关键词 transcranial magnetic stimulation Alzheimer’s disease power spectral density ELECTROENCEPHALOGRAM brain functional network
在线阅读 下载PDF
A series of iridium(Ⅲ)complexes with fluorophenyl isoquinoline ligand and low-efficiency roll-off properties:A density functional theory study
16
作者 QIN Zhengkun PAN Zicong +2 位作者 TIAN Hui ZHANG Wanyi SONG Mingxing 《无机化学学报》 北大核心 2025年第6期1235-1244,共10页
We have examined the theoretical implications of combining two main and three auxiliary ligands to form several Ir(Ⅲ)complexes featuring a transition metal as their core atom to identify some appropriate organic ligh... We have examined the theoretical implications of combining two main and three auxiliary ligands to form several Ir(Ⅲ)complexes featuring a transition metal as their core atom to identify some appropriate organic lightemitting diode(OLED)materials.By utilizing electronic structure,frontier molecular orbitals,minimum single-line absorption,triplet excited states,and emission spectral data derived from the density functional theory,the usefulness of these Ir(Ⅲ)complexes,including(piq)_(2)Ir(acac),(piq)_(2)Ir(tmd),(piq)_(2)Ir(tpip),(fpiq)_(2)Ir(acac),(fpiq)_(2)Ir(tmd),and(fpiq)_(2)Ir(tpip),in OLEDs was examined,where piq=1-phenylisoquinoline,fpiq=1-(4-fluorophenyl)isoquinoline,acac=(3Z)-4-hydroxypent-3-en-2-one,tmd=(4Z)-5-hydroxy-2,2,6,6-tetramethylhept-4-en-3-one,and tpip=tetraphenylimido-diphosphonate.These complexes all have low-efficiency roll-off properties,especially(fpiq)_(2)Ir(tpip).Some researchers have successfully synthesized complexes extremely similar to(piq)_(2)Ir(acac)through the Suzuki-Miyaura coupling reaction. 展开更多
关键词 density functional theory organic light-emitting diodes luminescent materials Ir(Ⅲ)complexes
在线阅读 下载PDF
Multi-objective optimization of microwave power transmission system architecture with engineering consideration
17
作者 DONG Shiwei SHINOHARA Naoki 《中国空间科学技术(中英文)》 北大核心 2025年第4期114-122,共9页
In the last decade,space solar power satellites(SSPSs)have been conceived to support net-zero carbon emissions and have attracted considerable attention.Electric energy is transmitted to the ground via a microwave pow... In the last decade,space solar power satellites(SSPSs)have been conceived to support net-zero carbon emissions and have attracted considerable attention.Electric energy is transmitted to the ground via a microwave power beam,a technology known as microwave power transmission(MPT).Due to the vast transmission distance of tens of thousands of kilometers,the power transmitting antenna array must span up to 1 kilometer in diameter.At the same time,the size of the rectifying array on the ground should extend over a few kilometers.This makes the MPT system of SSPSs significantly larger than the existing aerospace engineering system.To design and operate a rational MPT system,comprehensive optimization is required.Taking the space MPT system engineering into consideration,a novel multi-objective optimization function is proposed and further analyzed.The multi-objective optimization problem is modeled mathematically.Beam collection efficiency(BCE)is the primary factor,followed by the thermal management capability.Some tapers,designed to solve the conflict between BCE and the thermal problem,are reviewed.In addition to these two factors,rectenna design complexity is included as a functional factor in the optimization objective.Weight coefficients are assigned to these factors to prioritize them.Radiating planar arrays with different aperture illumination fields are studied,and their performances are compared using the multi-objective optimization function.Transmitting array size,rectifying array size,transmission distance,and transmitted power remaine constant in various cases,ensuring fair comparisons.The analysis results show that the proposed optimization function is effective in optimizing and selecting the MPT system architecture.It is also noted that the multi-objective optimization function can be expanded to include other factors in the future. 展开更多
关键词 space solar power satellite(SSPS) microwave power transmission(MPT) multi-objective function beam collection efficiency(BCE) system engineering
在线阅读 下载PDF
A dependency matrix processing algorithm to prioritize high incidence faults
18
作者 ZHANG Jiashuo CHEN Derong +2 位作者 GAO Peng ZHANG Jin’gang ZHANG Yulong 《Journal of Systems Engineering and Electronics》 2025年第4期962-971,共10页
The operational readiness test(ORT),like weapon testing before firing,is becoming more and more important for systems used in the field.However,the test requirement of the ORT is distinctive.Specifically,the rule of s... The operational readiness test(ORT),like weapon testing before firing,is becoming more and more important for systems used in the field.However,the test requirement of the ORT is distinctive.Specifically,the rule of selecting test items should be changed in different test turns,and whether there is a fault is more important than where the fault is.The popular dependency matrix(D-matrix)processing algorithms becomes low efficient because they cannot change their optimizing direc-tion and spend unnecessary time on fault localization and isola-tion.To this end,this paper proposes a D-matrix processing algorithm named piecewise heuristic algorithm for D-matrix(PHAD).Its key idea is to use a piecewise function comprised of multiple different functions instead of the commonly used fixed function and switch subfunctions according to the test stage.In this manner,PHAD has the capability of changing optimizing direction,precisely matching the variant test requirements,and generating an efficient test sequence.The experiments on the random matrixes of different sizes and densities prove that the proposed algorithm performs better than the classical algo-rithms in terms of expected test cost(ETC)and other metrics.More generally,the piecewise heuristic function shows a new way to design D-matrix processing algorithm and a more flexi-ble heuristic function to meet more complicated test requirements. 展开更多
关键词 fault diagnosis heuristic function operational readi-ness test piecewise function testability.
在线阅读 下载PDF
Functional cartography of heterogeneous combat networks using operational chain-based label propagation algorithm
19
作者 CHEN Kebin JIANG Xuping +2 位作者 ZENG Guangjun YANG Wenjing ZHENG Xue 《Journal of Systems Engineering and Electronics》 2025年第5期1202-1215,共14页
To extract and display the significant information of combat systems,this paper introduces the methodology of functional cartography into combat networks and proposes an integrated framework named“functional cartogra... To extract and display the significant information of combat systems,this paper introduces the methodology of functional cartography into combat networks and proposes an integrated framework named“functional cartography of heterogeneous combat networks based on the operational chain”(FCBOC).In this framework,a functional module detection algorithm named operational chain-based label propagation algorithm(OCLPA),which considers the cooperation and interactions among combat entities and can thus naturally tackle network heterogeneity,is proposed to identify the functional modules of the network.Then,the nodes and their modules are classified into different roles according to their properties.A case study shows that FCBOC can provide a simplified description of disorderly information of combat networks and enable us to identify their functional and structural network characteristics.The results provide useful information to help commanders make precise and accurate decisions regarding the protection,disintegration or optimization of combat networks.Three algorithms are also compared with OCLPA to show that FCBOC can most effectively find functional modules with practical meaning. 展开更多
关键词 functional cartography heterogeneous combat network functional module label propagation algorithm operational chain
在线阅读 下载PDF
Insights into the anisotropy in hydroxamic acid adsorption on different exposed crystal surfaces of malachite from first-principle calculations
20
作者 ZHANG Chen-yang LIU Si-yuan +6 位作者 JIANG Wan-yao ZHANG Hong-liang WU Lin-lin RAO Xin SUN Wei ZOU You PEI Yong 《Journal of Central South University》 2025年第7期2446-2462,共17页
The intricate grinding process exposes various cleavage surfaces of mineral particles.This paper systematically investigates the structural characteristics of exposed malachite crystal surfaces and the adsorption beha... The intricate grinding process exposes various cleavage surfaces of mineral particles.This paper systematically investigates the structural characteristics of exposed malachite crystal surfaces and the adsorption behavior and mechanism of hydroxamic acid and water molecules using first-principle density functional theory.The study reveals anisotropic surface energies among crystal surfaces,ranked as(201)>(100)>(110)>(001)>(010)>(201).The adsorption of hydroxamic acid and water molecules on malachite surfaces also exhibited anisotropy.The difference in adsorption strength between hydroxamic acid and water molecules on the six exposed surfaces followed the order of(110)>(100)>(010)>(001)>(201)>(201),and the resistance of water molecules to the adsorption of hydroxamic acid on the six exposed surfaces was(110)>(201)>(010)>(201)>(001)>(100).It indicates that the reagent exhibits a strong competitive advantage in adsorption on the(100)surface,and the hindrance of water molecules to reagent adsorption is relatively small,which is favorable for flotation.This study provides theoretical references and innovative insights for the precise design of flotation reagents,as well as for the meticulous optimization of mineral surface interfaces,with the objective of enhancing flotation separation. 展开更多
关键词 MALACHITE flotation reagents ADSORPTION surface density functional theory(DFT)
在线阅读 下载PDF
上一页 1 2 30 下一页 到第
使用帮助 返回顶部