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Optimization Problems of the Rank and Inertia Corresponding to a Hermitian Least-Squares Problem

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Wuhan University Journal of Natural Sciences 2015年第2期20卷 101-105页

作者： DAI lifang LIANG Maolin WANG Sanfu School of Mathematics and Statistics Tianshui Normal University

Generally, the least-squares problem can be solved by the normal equation. Based on the projection theorem, we propose a direct method to investigate the maximal and minimal ranks and inertias of the least-squares solutions of matrix equation AXB = C under Hermitian constraint, and the corresponding formulas for calculating the rank and inertia are derived.

关键词： matrix equation least-squares Hermitian solution rank inertia

The emerging cross-disciplinary studies of landscape ecology and biodiversity in China

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Journal of Geographical Sciences 2019年第7期29卷 1063-1080页

作者： SHEN Zehao LI Yiying YANG kang CHEN lifang Institute of Ecology College of Urban and Environmental Science the MOE Laboratory of Earth Surface Processes Peking University

The spatiotemporal landscape heterogeneity implies multiple biodiversity mechanisms across scales, and the cross-disciplinary studies between landscape ecology and biodiversity are becoming a new research field in China. This paper briefly reviews the development of the field by comparing papers published in international journals and Chinese journals;then it investigates the differences in the trends and focuses between international and Chinese studies. We also introduce several study areas that have emerged over the last 10 years in this field, including metacommunity assembly, landscape genetics, biodiversity and ecosystem service relationship, and landscape planning for biodiversity conservation. The major advances emerging in this field in China over the past 5 years can be classified into six subject areas: 1) effects of urban landscape and urbanization on biodiversity;2) altitudinal patterns of biodiversity in mountain landscapes;3) effects of topographic heterogeneity on plant community assembly and species coexistence;4) impacts of landscape patterns and processes on animal behaviors;5) forest fires and spatiotemporal patterns of vegetation responses;and 6) landscape ecology applications in natural conservation planning and design. In an attempt to promote cross-field studies between geography and ecology, this special issue collected 10 research articles, involving multiple landscape types and biological assemblages, in order to explore the interaction between landscape features and biodiversity. We anticipate that the future development of this active front will be primarily driven by the application of novel information techniques and the realistic demands of sustainability issues, in addition to answering scientific questions cross scales.

关键词： landscape ecology biodiversity cross-disciplinary study frontiers progresses

Ni_(2)P/NiMoP heterostructure as a bifunctional electrocatalyst for energy-saving hydrogen production

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eScience 2021年第1期1卷 69-74页

作者： Tongzhou Wang Xuejie Cao lifang Jiao Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Renewable Energy Conversion and Storage Center(RECAST)College of ChemistryNankai UniversityTianjin 300071China

Electrochemical water splitting is a sustainable and feasible strategy for hydrogen production but is hampered by the sluggish anodic oxygen evolution reaction(OER).Herein,an effective approach is introduced to significantly decrease the cell voltage by replacing the anodic OER with a urea oxidation reaction(UOR).A Ni_(2)P/NiMoP nanosheet catalyst with a hierarchical architecture is uniformly grown on a nickel foam(NF)substrate through a simple hydrothermal and phosphorization *** Ni_(2)P/NiMoP achieves impressive HER activity,with a low overpotential of only 22 mV at 10 mA cm^(-2)and a low Tafel slope of 34.5 mV dec^(−1).In addition,the oxidation voltage is significantly reduced from 1.49 V to 1.33 V after the introduction of 0.33 M ***,a two-electrode electrolyzer employing Ni_(2)P/NiMoP as a bifunctional catalyst exhibits a current density of 10 mA cm^(-2)at a cell voltage of 1.35 V and excellent long-term durability after 80 h.

关键词： Hydrogen production Hierarchical architecture Urea oxidation reaction Bifunctional catalyst

BE-PIGS: a base-editing tool with deaminases inlaid into Cas9 PI domain significantly expanded the editing scope

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Signal Transduction and Targeted Therapy 2019年第1期4卷 327-329页

作者： Yanhong Wang lifang Zhou Nan Liu Shaohua Yao State Key Laboratory of Biotherapy and Cancer Center West China HospitalSichuan University610041 Chengdu People’s Republic of China

Dear Editor,The discovery of base-editing tools sheds new light on both basic biomedical research and clinical therapeutics.1,2 Although showing profound performance in a wide range of applications,current base editors have their *** particular,the narrow editing windows of these base editors have significantly limited their targetable *** current base editors,the most frequent way to tether deaminase is to fuse it to the N-terminus of the Cas9 protein through flexible peptide *** editors derived from Streptococcus pyogenes Cas9(SpyCas9)or its variants can efficiently edit desired bases in an~5 nt wide window within the detached,non-target strand(NTS).Maximum editing typically occurs around positions 5–7,counting from the 5′end of the protospacer,which is about 15 nt away from the protospacer adjacent motif(PAM).

关键词： base expanded editing

Efficient Knoevenagel condensation catalyzed by imidazole-based halogenfree deep eutectic solvent at room temperature

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Green Energy & Environment 2020年第2期5卷 124-129页

作者： Hao Qin Yishan Zhou Qian Zeng Hongye Cheng lifang Chen Bingjian Zhang Zhiwen Qi Max Planck Partner Group at the State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and Technology130 Meilong RoadShanghai200237China School of Chemical Engineering and Technology Sun Yat-Sen University135 Xingang West RoadGuangzhou510275China

For the first time,we employed the halogen-free deep eutectic solvent(DES)into the Knoevenagel condensation between aromatic aldehydes and active methylene compounds at room *** DESs[3Im:PTSA]and[4Im:PTSA]were prepared by imidazole(Im)and p-tol-uenesulfonic acid(PTSA),which were experimentally screened from a series of organic acids with imidazole.a,b-Unsaturated carbonyl compounds were obtained in good to excellent yields under solvent-free conditions with fast reaction *** two DESs can be reused for multiple times with no loss of catalytic activity.

关键词： Halogen-free DES Knoevenagel condensation Room temperature Recyclable catalyst Solvent-free condition

Improved remote sensing image target detection based on YOLOv7

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Optoelectronics Letters 2024年第4期20卷 234-242页

作者： XU Shuanglong CHEN Zhihong ZHANG Haiwei XUE lifang SU Huijun School of Integrated Circuit Science and EngineeringTianjin University of Technology Tianjin 300384China

Remote sensing images are taken at high altitude from above,with complex spatial scenes of images and a large number of target *** detection of image targets on large scale remote sensing images suffers from the problem of small target size and target *** paper proposes an improved model for remote sensing image detection based on you only look once version 7(YOLOv7).First,the small-scale detection layer is added to reacquire tracking frames to improve the network’s recognition ability of small-scale targets,and then Bottleneck Transformers are fused in the backbone to make full use of the convolutional neural network(CNN)+Transformer architecture to enhance the feature extraction ability of the *** that,the convolutional block attention module(CBAM)mechanism is added in the head to improve the model’s ability of small-scale ***,the non-maximum suppressed(NMS)of YOLOv7 algorithm is changed to distance intersection over union-non maximum suppression(DIOU-NMS)to improve the detection ability of overlapping targets in the *** results show that the method in this paper can improve the detection rate of small-scale targets in remote sensing images and effectively solve the problem of high overlap and is tested on the NWPU-VHR10 and DOTA1.0 datasets,and the accuracy of the improved model is improved by 6.3%and 4.2%,respectively,compared with the standard YOLOv7 algorithm.

关键词： image network union

Molecule configurations modulate packing array and charge transfer in cocrystal engineering

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Science China Chemistry 2024年第2期67卷 512-516页

作者： Shenglong An Mengyuan Qiao Xin Jin Xuanying Chen Jianhua Su lifang Guo Zhiyun Zhang Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering Feringa Nobel Prize Scientist Joint Research CentreFrontiers Science Center for Materiobiology and Dynamic ChemistryEast China University of Science&TechnologyShanghai200237China

Organic cocrystal as an emerging assembly strategy has received increasing attention in constructing multiple functional materials,through continually screening suitable constituent monomers or changing their stoichiometry ***,the role of molecule configuration in the cocrystal field is rarely explored despite the fascinating potential in regulating the packing *** this study,the N,N′-diphenyl-5,10-dihydrophenazine derivatives(DPPs) with the flexible scaffold and different methyl substitutions are selected as the donors bearing various molecular *** a simple collaborative way,a series of cocrystals based on DPPs and OFN(octafluoronaphthalene) are fabricated,exhibiting two self-adaptive molecular stacking arrays.X-ray crystallographic analysis and theoretical calculation unveil their different π···π interactions and charge transfer characters,leading to the significant emission redshift up to 125 nm compared with individual *** a result,controllable molecule stacking structure,tunable emission,and charge transfer properties can be *** study provides a new perspective to reveal the structure-property relationships at the molecular level by controlling the molecule configuration in cocrystal engineering,contributing to the development of cocrystal theoretical physics and organic functional materials.

关键词： cocrystals molecular configuration self-adaptive packing mode charge transfer

Improvement of Ductility of Powder Metallurgy Titanium Alloys by Addition of Rare Earth Element

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Journal of Materials Science & Technology 2006年第4期22卷 465-469页

作者： Yong LIU lifang CHEN Weifeng WEI Huiping TANG Bin LIU Baiyun HUANG State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China Northwest Institute of Nonferrous Metals Research Xi＇an 710016 China

Ti-4.5Al-6.0Mo-1.5Fe, Ti-6Al-1Mo-1Fe and Ti-6Al-4V alloys were prepared by blended elemental powder metallurgy （PM） process, and the effects of Nd on the microstructures and mechanical properties were investigated by scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and X-ray diffraction （XRD）. It was found out that the addition of Nd increased the density of sintered titanium alloys slightly by a maximum increment of 1% because small amount of liquid phase occurred during sintering. The addition of Nd shows little effect on the improvement of tensile strength, while the elongation is significantly improved. For example, the elongation of ***-6.0Mo-1.5Fe can be increased from 1% without addition of Nd to 13% at a Nd content of 1.2 wt pct.

关键词： Powder metallurgy titanium alloy Mechanical properties Microstructure Rare earth element

Responses of nitrification performance,triclosan resistome and diversity of microbes to continuous triclosan stress in activated sludge system

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Journal of Environmental Sciences 2020年第6期32卷 211-223页

作者： Da Zhang Jingfeng Gao lifang Zhang Wenzhi Zhang Jingxin Jia Huihui Dai Zhiqi Wang National Engineering Laboratory for Aduanced Municipal Wastewater Treatment and Reuse Technology College of Environmental and Energy EngineeringBeijing University of TechnologyBeijing 100124China

Triclosan(TCS)is commonly found in wastewater treatment plants,which often affects biological treatment *** responses of nitrification,antibiotic resistome and microbial community under different TCS concentrations in activated sludge system were evaluated in this *** experiment was conducted in a sequencing batch reactor(SBR)for 240 *** PCR results demonstrated that the abundance of ammonium oxidizing bacteria could be temporarily inhibited by 1 mg/L TCS and then gradually *** the abundances of nitrite oxidizing bacteria(NOB)under 2.5 and 4 mg/L TCS were three orders of magnitude lower than that of seed sludge,which accounted for partial *** the addition of TCS was stopped,the abundance of NOB *** mass balance experiments of TCS demonstrated that the primary removal pathway of TCS changed from adsorption to biodegradation as TCS was continuously added into the SBR ***,TCS increased the abundance of mexB,indicating the efflux pump might be the main TCS-resistance *** a response to TCS,bacteria could secrete more protein(PN)than ***-dimensional excitation-emission matrix revealed that tryptophan PN-like substances might be the main component in PN to resist ***-throughput sequencing found that the relative abundances of Paracoccus,Pseudoxanthomonas and Thauera increased,which could secrete extracellular polymeric substances(EPS).And Sphingopyxis might be the main TCS-degrading ***,TCS could cause partial nitrification and increase the relative abundances of EPS-secreting bacteria and TCS-degrading bacteria.

关键词： Triclosan Partial nitrification Nitrite oxidizing bacteria Triclosan resistome Microbial community