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Scaling correction approaches for reducing delocalization error in density functional approximations

Science China Chemistry 2015年第12期58卷 1825-1844页

作者： Xiao Zheng Chen Li Dadi Zhang weitao yang Synergetic Innovation Center of Quantum Information and Quantum Physics & Hefei National Laboratory for Physical Sciences at the Microscale Department of Chemistry Duke University Key Laboratory of Theoretical Chemistry of Environment

Delocalization error associated with the presently used density functional approximations is one of the main sources of errors which plague density functional theory calculations. In this paper, we give a comprehensive review on scaling correction(SC) approaches developed recently for reducing the delocalization error. The global and local SC approaches impose the rigorous Perdew-Parr-Levy-Balduz condition that the total electronic energy should scale linearly between integer electron numbers, on systems involving global and local fractional electron distributions, respectively. After presenting the theoretical background and mathematical formulation of scaling corrections, we demonstrate that they lead to universal alleviation of delocalization error. This is exemplified by the substantial improvement for the prediction of a wide range of electronic properties, including Kohn-Sham frontier orbital energies and band gaps, dissociation behavior of molecules, reaction barriers, electric polarizabilities, and charge-transfer species. The encouraging performances of SC approaches highlight their practicality and usefulness, and also affirm that an explicit treatment of fractional electron distributions is essentially important for reducing the intrinsic delocalization error. The existing limitations, the remaining challenges, and the future perspectives of SC are also discussed. Moreover, the SC approaches are compared with some existing methods attempting to remove the self-interaction error, such as the Perdew-Zunger self-interaction correction, the local hybrid hyper-generalized gradient approximations, and the rangeseparated density functional approximations. The unique advantages of SC suggest that it could open a novel and potentially paradigm-changing route for advancing density functional theory methods towards chemical accuracy.

关键词： density functional theory scaling correction approach exchange-correlation functional density functional approximations

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Kinetics of water–isocyanate reaction in N,N-dimethylformamide

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Chinese Journal of Chemical Engineering 2017年第10期25卷 1435-1441页

作者： Zhirong Chen weitao yang Hong Yin Shenfeng Yuan College of Chemical and Biologlical Engineering Zhejiang University Hangzhou 310027 China

The uncatalyzed reaction of p-tolyl isocyanate(p-TI)with water in N,N-dimethylformamide(DMF)was investigated by high performance liquid chromatography(HPLC).The reactions were carried out at different temperatures from 293 K to 323 K,using various molar ratios of water to ***,as a special amide,was proved to be an efficient catalyst for water–isocyanate *** the reaction conditions in this study,substituted urea was the only final product *** appreciable amount of intermediate p-toluidine was *** of the isocyanate group as well as the amine and urea were determined as a function of *** kinetic equations were deduced for each of the substance on the basis of a multistep mechanism,instead of a simple second order reaction as *** constants were calculated using the software ***,the effects of temperature and concentrations of reactants on the reaction rate and amine content were *** activation energy of each step was also determined.

关键词： N-二甲基甲酰胺甲苯异氰酸酯反应动力学高效液相色谱法反应物浓度水异氰酸酯基团 MATLAB

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Review of Computational Approaches to Optimization Problems in Inhomogeneous Rods and Plates

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Communications on Applied Mathematics and Computation 2024年第1期6卷 236-256页

作者： weitao Chen Chiu-Yen Kao Department of Mathematics University of California at Riverside900 University AveRiversideCA92521USA Department of Mathematical Sciences Claremont McKenna College850 Columbia AveClaremontCA91711USA

In this paper,we review computational approaches to optimization problems of inhomogeneous rods and *** consider both the optimization of eigenvalues and the localization of *** problems are motivated by physical problems including the determination of the extremum of the fundamental vibration frequency and the localization of the vibration *** demonstrate how an iterative rearrangement approach and a gradient descent approach with projection can successfully solve these optimization problems under different boundary conditions with different densities given.

关键词： Inhomogeneous rods and plates Bi-Laplacian Optimization of eigenvalues Localization of eigenfunctions Rearrangement

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Localized orbital scaling correction for systematic elimination of delocalization error in density functional approximations

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National Science Review 2018年第2期5卷 203-215页

作者： Chen Li Xiao Zheng Neil Qiang Su weitao yang Department of Chemistry Duke University Synergetic Innovation Center of Quantum Information and Quantum Physics Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China CAS Center for Excellence in Nanoscience University of Science and Technology of China Department of Physics Duke University Key Laboratory of Theoretical Chemistry of Environment School of Chemistry and EnvironmentSouth China Normal University

The delocalization error of popular density functional approximations(DFAs) leads to diversified problems in present-day density functional theory calculations. For achieving a universal elimination of delocalization error, we develop a localized orbital scaling correction(LOSC) framework, which unifies our previously proposed global and local scaling approaches. The LOSC framework accurately characterizes the distributions of global and local fractional electrons, and is thus capable of correcting system energy, energy derivative and electron density in a self-consistent and size-consistent manner. The LOSC–DFAs lead to systematically improved results, including the dissociation of cationic species, the band gaps of molecules and polymer chains, the energy and density changes upon electron addition and removal, and photoemission spectra.

关键词： localized orbital scaling correction delocalization error density functional approximation localized frontier orbital local fraction orbitalet

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Curvature Quantified Douglas-Peucker-based Phasor Measurement Unit Data Compression Method for Power System Situational Awareness

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Protection and Control of Modern Power Systems 2024年第2期9卷 128-137页

作者： weitao Tan Tianhan Zhang Yuanqian Ma Shengyuan Liu Li yang Zhenzhi Lin College of Electrical Engineering Zhejiang UniversityHangzhouChina Electrical Engineering and its Automation from Sichuan University ChengduChina Electrical Engineering from Shandong University JinanChina Electrical Engineering from Zhejiang University HangzhouChina College of Electrical Engineering Zhejiang UniversityHangzhou 310027China

Facing constraints imposed by storage and bandwidth limitations,the vast volume of phasor meas-urement unit(PMU)data collected by the wide-area measurement system(WAMS)for power systems cannot be fully *** limitation significantly hinders the effective deployment of situational awareness technologies for systematic *** this work,an effective curvature quantified Douglas-Peucker(CQDP)-based PMU data compression method is proposed for situational awareness of power ***,a curvature integrated distance(CID)for measuring the local flection and fluc-tuation of PMU signals is *** Doug-las-Peucker(DP)algorithm integrated with a quan-tile-based parameter adaptation scheme is then proposed to extract feature points for profiling the trends within the PMU *** allows adaptive adjustment of the al-gorithm parameters,so as to maintain the desired com-pression ratio and reconstruction accuracy as much as possible,irrespective of the power system ***-nally,case studies on the Western Electricity Coordinat-ing Council(WECC)179-bus system and the actual Guangdong power system are performed to verify the effectiveness of the proposed *** simulation results show that the proposed method achieves stably higher compression ratio and reconstruction accuracy in both steady state and in transients of the power system,and alleviates the compression performance degradation problem faced by existing compression *** Terms—Curvature quantified Douglas-Peucker,data compression,phasor measurement unit,power sys-tem situational awareness.

关键词： Curvature quantified Douglas-Peucker data compression phasor measurement unit power sys-tem situational awareness

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Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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华南师范大学学报(自然科学版) 2014年第6期 137-138页

作者： yang weitao Department of Chemistry and Physics Duke University Key Laboratory of Theoretical Chemistry of Environment Ministry of Education School of Chemistry and Environment South China Normal University

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear *** formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation *** illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-

关键词： RPA TDA Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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Kinematic calibration method with high measurement efficiency and robust identification for hybrid machine tools

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Chinese Journal of Aeronautics 2024年第3期37卷 468-482页

作者： Liping WANG Mengyu LI Guang YU weitao LI Xiangyu KONG State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Beijing Key Laboratory of Precision/Ultra-precision Manufacturing Equipment and Control Beijing 100084China

Geometric error is the main factor affecting the machining accuracy of hybrid machine *** calibration is an effective way to improve the geometric accuracy of hybrid machine *** necessity to measure both position and orientation at each pose,as well as the instability of identification in case of incomplete measurements,severely affects the application of traditional calibration *** this study,a kinematic calibration method with high measurement efficiency and robust identification is proposed to improve the kinematic accuracy of a five-axis hybrid machine ***,the configuration is introduced,and an error model is ***,by investigating the mechanism error characteristics,a measurement scheme that only requires tool centre point position error measurement and one alignment operation is ***,by analysing the effects of unmeasured degrees of freedom(DOFs)on other DOFs,an improved nonlinear least squares method based on virtual measurement values is proposed to achieve stable parameter identification in case of incomplete measurement,without introducing additional ***,the proposed calibration method is verified through simulations and *** proposed method can efficiently accomplish the kinematic calibration of the hybrid machine *** accuracy of the hybrid machine tool is significantly improved after calibration,satisfying actual aerospace machining requirements.

关键词： Hybrid machine tool Calibration Measurement scheme Improved nonlinear least squares method Virtual measurement values

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Black phosphorus nanoflakes as morphology modifier for efficient fullerene-free organic solar cells with high fill-factor and better morphological stability

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Nano Research 2019年第4期12卷 777-783页

作者： weitao yang Long Ye Fenfa Yao Chuanhong Jin Harald Ade Hongzheng Chen State Key Laboratory of Silicon Materials MOE Key Laboratory of Macromolecular Synthesis and Functionalization& Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 China Department of Physics Organic and Carbon Electronics Laboratory (ORaCEL) North Carolina State University Raleigh NC 27695 USA State Key Laboratory of Silicon Materials School of Materials Science and Engineering Zhejiang University Hangzhou 310027 China

Morphology of the donor:acceptor blend plays a critical role in the photovoltaic performance of the organic solar cells (OSCs).Herein,liquid-phase-exfoliated black phosphorus nanoflakes (BPNFs),for their outstanding electronic property and good compatibility to solution process,were applied to fullerene-free OSCs as morphology *** by X-ray scattering measurements,the PTB7-Th:IEICO-4F blends incorporated with BPNFs exhibit more ordered π-π stacking and promoted domain purity,contributing to lower charge transport resistance and suppressed charge recombination within the bulk heterojunction (BHJ).As a result,a high fill factor (FF) of 0.73 and a best power conversion efficiency (PCE) of 12.2% were obtained for fullerene-free OSCs based on PTB7-Th:IEICO-4F blends incorporating with BPNFs,which is among the highest FF of the as-cast fullerene-free OSCs with PCE over 12%.More importantly,the embedded BPNFs help to improve the morphological stability of the devices probably by retarding the phase mixing in the BHJ during the aging ***,analogous enhancements were observed in another fullerene-free OSCs based on PBDB-T:*** a word,this work provides a new strategy of using two-dimentional nanoflakes as facile and universal morphology modifier for efficient fullerene-free OSCs.

关键词： fullerene-free organic solar cells black phosphorus nanoflakes morphology tuning device stability

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A phylogenetic approach identifies patterns of beta diversity and floristic subregions of the Qinghai-Tibet Plateau

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Plant Diversity 2024年第1期46卷 59-69页

作者： Haibin Yu Man yang Zixin Lu weitao Wang Fangyuan Yu Yonghua Zhang Xue Yin Hongjun Yu Junjie Hu David C.Deane Key Laboratory of Conservation and Application in Biodiversity of South China School of Life SciencesGuangzhou UniversityGuangzhou 510006China School of Ecology Sun Yat-Sen UniversityShenzhen 510275China School of Geography and Remote Sensing Guangzhou UniversityGuangzhou 510006China College of Life and Environmental Science Wenzhou UniversityWenzhou 325035China Centre for Future Landscapes and Department of Environment and Genetics La Trobe UniversityBundooraVIC 3083Australia

Patterns of taxonomic and phylogenetic beta diversity and their relationships with environmental correlates can help reveal the origin and evolutionary history of regional *** Qinghai-Tibet Plateau(QTP)harbors an exceptionally diverse flora,however,a phylogenetic perspective has rarely been used to investigate its beta diversity and floristic *** this study,we used a phylogenetic approach to identify patterns of beta diversity and quantitatively delimit floristic regions on the Qinghai-Tibet *** also examined the relationships between multifaceted beta diversity,geographical distance,and climatic difference,and evaluated the relative importance of various factors(i.e.,climate,topography and history)in shaping patterns of beta diversity.Sørensen dissimilarity indices indicated that patterns of species turnover among sites dominated the *** also found that patterns of both taxonomic and phylogenetic beta diversity were significantly related to geographical distance and climatic *** environmental factors that contributed most to these patterns of beta diversity include annual precipitation,mean annual temperature,climatic gradients and climatic *** dendrograms of dissimilarity and non-metric multidimensional scaling ordination based on phylogenetic beta diversity data identified ten floristic subregions in the *** results suggest that the contemporary environment and historical climate changes have filtered species composition among sites and eventually determined beta diversity patterns of plants in the QTP.

关键词： Biogeographical regionalization Phylogenetic beta diversity Seed plants Sørensen dissimilarity Qinghai-Tibet Plateau

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综合营养管理对妊娠期糖尿病患者的血糖及妊娠结局的影响

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基础医学与临床 2024年第4期44卷 434-439页

作者：王瑞柒铭铭杨微涛黄健肖锦艳李一春王永红刘燕萍中国医学科学院北京协和医学院北京协和医院临床营养科北京100730 株洲市中心医院临床营养科湖南株洲412001 长沙市妇幼保健院妇产科湖南长沙410007 中南大学湘雅二医院妇产科湖南长沙410011 岳阳市妇幼保健院妇产科湖南岳阳414021 南华大学附属第二医院妇产科湖南衡阳421000 郴州市第一人民医院妇产科湖南郴州423003

目的探讨综合营养管理对妊娠期糖尿病(GDM)患者糖脂代谢及妊娠结局的影响。方法本研究纳入了2021年5月~2021年7月共121名在全国6个分中心医院产科建档的妊娠24~28周的GDM孕妇,随机分为干预组(n=74)和对照组(n=47)。干预组接受综合营... 详细信息

目的探讨综合营养管理对妊娠期糖尿病(GDM)患者糖脂代谢及妊娠结局的影响。方法本研究纳入了2021年5月~2021年7月共121名在全国6个分中心医院产科建档的妊娠24~28周的GDM孕妇,随机分为干预组(n=74)和对照组(n=47)。干预组接受综合营养管理,包括至少6次门诊干预、个体化营养管理及妊娠期糖尿病半日规范化门诊宣教,并持续使用动态血糖监测仪和指血血糖监测仪监测血糖,每4周进行糖化白蛋白和尿常规检测,记录体质量、体成分、饮食运动实施、胎儿发育以及并发症发生情况。对照组接受常规营养指导。比较两组孕37周的血糖相关指标、分娩前的体质量增加和部分脂类代谢指标、妊娠结局以及产后42 d口服葡萄糖耐量试验(OGTT)结果的差异。结果与对照组相比,干预组孕妇的产前空腹血糖(P=0.006)、餐后2 h静脉血浆葡萄糖(P=0.009)、血酮(P=0.044)水平显著降低。两组间体质量增加值与体质量达标率没有显著性差异。干预组孕妇的产后2h OGTT试验结果小于对照组(P=0.006),差异有统计学意义,子痫前期的发生率和产后出血量低于对照组,但两组之间没有统计学差异。对于新生儿来说,干预组的巨大儿(P=0.042)、剖宫产(P=0.048)的发生率略低于对照组,结果有统计学差异。其他不良妊娠结局在两组之间没有统计学差异。结论强化综合营养管理能够更好地控制孕妇血糖水平,改善GDM妇女的孕产妇和新生儿结局。

关键词：妊娠期糖尿病综合营养管理妊娠结局

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