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Synthesis of Helical Poly(phenylacetylene)s Carrying Dendritic Pendants with Varied Branching Densities Through Polymerization in Different Solvents

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Chinese Journal of Polymer Science 2023年第10期41卷 1543-1554页

作者： Zhen-Zhen Sun yan-ning Zhang hao-Yu Qiu Xue-Ting Lu Liang-Xuan ren Le-Fei Shen Wen Li Afang Zhang International Joint Laboratory of Biomimetic and Smart Polymers School of Materials Science and EngineeringShanghai UniversityShanghai200444China

Helical poly(phenylacetylene)s(PPAs)have received extensive attention because of their features in dynamic chirality and promising ***,understanding relationship among the polymer molecular structures,polymerization conditions and tunability of their chirality is of key scientific ***,we developed a novel class of dendronized PPAs carrying 3-fold dendritic oligo(ethylene glycols)(OEGs)via alanine linkage,and found that these bulky polymers exhibited tunable helical conformations through thermally-mediated dehydration and ***,we report on synthesis of a homologous series of dendronized PPAs that carry 2-fold,3-fold or 6-fold dendritic OEG pendants,and focus on effects of molecular topological structures,peripheral units and polymerization solvents on the thermoresponsiveness and their conformation switching *** of branching density and peripheral units(ethoxyl or methoxyl)of the dendritic OEG pendants were examined,and found to play a decisive role on the helical conformation and thermoresponsiveness of these dendronized PPAs due to their different bulkiness and overall *** addition,different polymerization solvents were checked for their possible influence on the polymerization,thermoresponsive behavior and the chirality of the resulting *** polymerization in selective solvents like water or methanol,the obtained dendronized PPAs exhibited weak thermal transitions,while polymerization in non-selective solvent like THF furnished PPAs with characteristic thermoresponsive behavior,indicating that solvents were involved in the process of polymerization of the dendronized *** interestingly,different chiralities of the PPAs through polymerization in various solvents were retained,irrelevant to the purification process and solvents *** work suggests that the topological structures together with polymerization solvents can modulate the thermoresponsive behavior and h

关键词： Helical polymer Dendronized polymer Thermores ponsive polymer Solvation Dendritic oligoethylene glycol

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Local measurements of tunneling magneto-conductance oscillations in monolayer, Bernal-stacked bilayer, and ABC-stacked trilayer graphene

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Science China(Physics,Mechanics & Astronomy) 2021年第8期64卷 72-77页

作者： Ya-ning ren Mo-Han Zhang Chao yan Yu Zhang Lin He Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China

Shubnikov-de Haas oscillations are the most well-known magneto-oscillations in transport measurements. They are caused by Landau quantization of two-dimensional(2D) electron systems in the presence of a magnetic field. Here we demonstrate that a scanning tunneling microscope(STM) can locally measure similar magneto-oscillations in 2D systems. In Landau level spectroscopy measurements with fine magnetic-field increments, we observed fixed-energy magnetic-field-dependent oscillations of the local density of states. From the measured tunneling magneto-conductance oscillations acquired by STM, energymomentum dispersions and Berry phases of a monolayer, Bernal-stacked bilayer, and ABC-stacked trilayer graphene were obtained. The reported method is applicable to a wide range of materials because it can obtain the magneto-oscillations of 2D systems larger than the magnetic length;importantly, it also requires no gate electrode.

关键词： graphene magneto-conductance oscillations scanning tunneling microscopy energy-momentum dispersion Berry phase

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Recent progress in CdS-based S-scheme photocatalysts

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Journal of Materials Science & Technology 2024年第4期171卷 162-184页

作者： Yajing ren Yunfeng Li Guixu Pan ning Wang yan Xing Zhenyi Zhang College of Environmental and Chemical Engineering Xi’an Polytechnic UniversityXi’an 710048China Jilin Provincial Key Laboratory of Advanced Energy Materials Department of ChemistryNortheast Normal UniversityChangchun 130024China Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission Key Laboratory of Photosensitive Materials and Devices of Liaoning ProvinceSchool of Physics and Materials EngineeringDalian Minzu UniversityDalian 116600China

Photocatalytic technology with sunlight as driving force can convert solar energy into other energy sources for storage and further *** sulfide(CdS),as a typical reducing semiconductor of metal sulfides,represents an interesting research hotspot in photocatalysis due to its suitable bandgap(2.4 eV)for utilizing visible light and strong reducing ability for inducing surface catalytic ***,the photocatalytic performance of CdS is still limited by its fast carrier recombination and serious *** far,CdS semiconductor has been widely developed as a typical reducing photocatalyst in constructing novel S-scheme heterojunction to overcome the above *** this review,the de-sign concepts,basic principles,and charge transfer characteristics of CdS-based S-scheme heterojunction photocatalysts have been comprehensively *** advanced and effective characterization methods for studying the mechanism of CdS-based S-scheme heterojunction are analyzed in ***-thermore,we also summarize the typical applications of CdS-based S-scheme heterojunctions for water splitting,CO_(2) reduction,pollutant degradation,***,according to the current investigation sta-tus,some drawbacks in the current synthetic strategy,mechanism exploration,and application prospect of CdS-based S-scheme heterojunction are proposed,which need to be addressed by further expansion and innovative research.

关键词： Photocatalysis CdS semiconductor Heterojunction S-scheme Metal sulfide

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Importance of plant and bird traits on the seed removal pattern of endangered trees across different forest patches in southeast China

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Ecological Processes 2020年第1期9卷 499-504页

作者： ning Li Shuai Zhang Yuan-hao ren Zheng Wang Institute of Applied Ecology Nanjing Xiaozhuang UniversityNanjing 211171JiangsuChina College of Biology and Environmental Science Nanjing Forestry UniversityNanjing 210037China

Seed removal by birds has been recognized as an important part of seed dispersal process in patchy forest areas;however,few studies have focused on the contribution of both plant and bird traits to seed *** this study,field data of seed removal for Taxus chinensis was combined with the data of bird and plant traits for *** relevant traits of plants and birds that influenced ***-bird interaction were identified in a remnant patchy forest in yew ecological garden,Fujian Province,southeast *** bird species were found to forage and remove the seeds of *** number of bird species varied in different forest patches;however,their contribution to seed removal showed no significant *** bird and plant traits were found to affect seed *** seed removal rate was positively affected by bird traits,such as foraging frequency and wing length,but decreased with body *** plant traits,such as number of fruits,tree height,canopy density,and crown width,which are related to safe shelter and food resource conditions,increased the seed removal *** results underline the functional importance of bird and plant traits in the seed removal from endangered trees in patchy ***,future conservation strategies should prioritize and recognize the role of both plant and bird traits in seed dispersal in remnant patchy forests.

关键词： Seed removal Bird trait Plant trait Hypsipetes leucocephalus Patchy forest

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Distribution Pattern of Photosynthetic Picoplankton and Heterotrophic Bacteria in the Northern South China Sea

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Journal of Integrative Plant Biology 2007年第3期49卷 282-298页

作者： Yu-Ming Cai Xiu-ren ning Cheng-Gang Liu Qiang hao Ocean University of China Qingdao 266003 China State Oceanic Administration Key Laboratories of Marine Ecosystem and Biogeochemistry Hangzhou 310012 China Second Institute of Oceanography SOA Hangzhou 310012 China

The environmental regulation of plcoplankton distribution in the northern South China Sea was examined In winter and summer of 2004. The average abundance of Synechococcus, Prochlorococcus, and heterotrophlc bacteria was lower In winter （30, 21, and 780×10^3 cells/cm^3, respectively） than In summer （53, 85, and 1 090×10^3 cells/cm^3, respectively）, but the seasonal pattern was opposite for plcoeukaryotlc phytoplankton （4 500 and 3 200 cells/cm^3 In winter and summer, respectively）. Synechococcus, picoeukaryotes, and bacteria were most abundant in the nutrient-rich coastal zone and continental shelf, but Prochlorococcus was most abundant In the continental slope and open ocean. The vertical distribution of each photosynthetic group and heterotrophlc bacteria changed between the two seasons. Synechococcus populations with apparently different phycoerythrobilin content occurred at many stations In the summer. In addition, two different populations of Prochlorococcus were found：（i） small, weakly fluorescing cells in the surface layer; and （ii） larger, strongly fluorescent cells In the deep layer. The distribution pattern of photosynthetic plcoplankton and heterotrophlc bacteria depends on environmental effects and their ecophyslologlcal differences. The distribution of Synechococcus appeared to be related to nutrient availability, whereas the distribution of Prochlorococcus appeared to be limited by temperature. Synechococcus was the only plcophytoplankton with a consistent strong relationship with bacteria.

关键词： diel variation heterotrophic bacteria photosynthetic picoeukaryotes Prochlorococcus South China Sea spatial distribution structure standing stock Synechococcus

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Multiple well-differentiated retroperitoneal liposarcomas with different patterns of appearance on computed tomography:A case report

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World Journal of Clinical Cases 2021年第7期9卷 1661-1667页

作者： Tian-hao Xie Xiang-Xiang ren yan Fu Si-ning Ha Li-Tao Liu Xiao-Shi Jin Department of General Surgery Affiliated Hospital of Hebei UniversityBaoding 071000Hebei ProvinceChina Department of Ophthalmology Baoding First Central HospitalBaoding 071000Hebei ProvinceChina

BACKGROUND Primary retroperitoneal liposarcoma(PRPLS)is a rare soft tissue tumor with nonspecific clinical symptoms;it has different computed tomography(CT)image features according to pathological *** patients with a single tumor have been previously reported in the *** present an exceptional case of a PRPLS patient with multiple large tumors exhibiting different patterns of appearance on CT and confirmed as atypical lipomatous tumor/welldifferentiated liposarcoma by postoperative *** SUMMARY A 64-year-old man presented with abdominal distension for 1 *** patient was diagnosed with PRPLS based on physical examination,laparotomy,ultrasonography,CT scan,and *** of the tumors were completely resected through surgery and confirmed as atypical lipomatous tumor/welldifferentiated liposarcoma by postoperative *** postoperative course was uneventful without recurrence or metastasis,as demonstrated by abdominalpelvic CT during an 18 mo *** Multiple large Well-differentiated liposarcomas with different patterns of appearance on CT image can occur simultaneously in the same patient,to which more attention should be paid to make an effective differential diagnosis.

关键词： Retroperitoneal liposarcoma Soft tissue tumor Complete resection Recurrence Case report

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Dynamic network embedding via incremental skip-gram with negative sampling

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Science China(Information Sciences) 2020年第10期63卷 89-107页

作者： hao PENG Jianxin LI hao yan Qiran GONG Senzhang WANG Lin LIU Lihong WANG Xiang ren Beijing Advanced Innovation Center for Big Data and Brain Computing Beihang University State Key Laboratory of Software Development Environment Beihang University Collage of Computer Science and Technology Nanjing University of Aeronautics and Astronautics National Computer Network Emergency Response Technical Team/Coordination Center of China Department of Computer Science University of Southern California

Network representation learning, as an approach to learn low dimensional representations of vertices, has attracted considerable research attention recently. It has been proven extremely useful in many machine learning tasks over large graph. Most existing methods focus on learning the structural representations of vertices in a static network, but cannot guarantee an accurate and efficient embedding in a dynamic network scenario. The fundamental problem of continuously capturing the dynamic properties in an efficient way for a dynamic network remains unsolved. To address this issue, we present an efficient incremental skip-gram algorithm with negative sampling for dynamic network embedding, and provide a set of theoretical analyses to characterize the performance guarantee. Specifically, we first partition a dynamic network into the updated, including addition/deletion of links and vertices, and the retained networks over time. Then we factorize the objective function of network embedding into the added, vanished and retained parts of the network. Next we provide a new stochastic gradient-based method, guided by the partitions of the network, to update the nodes and the parameter vectors. The proposed algorithm is proven to yield an objective function value with a bounded difference to that of the original objective function. The first order moment of the objective difference converges in order of O（1/n;）, and the second order moment of the objective difference can be stabilized in order of O（1）. Experimental results show that our proposal can significantly reduce the training time while preserving the comparable performance. We also demonstrate the correctness of the theoretical analysis and the practical usefulness of the dynamic network embedding. We perform extensive experiments on multiple real-world large network datasets over multi-label classification and link prediction tasks to evaluate the effectiveness and efficiency of the proposed framework, and up to

关键词： dynamic network embedding bound and convergence analysis multi-label classification link prediction

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Trimethyl phosphate-enhanced polyvinyl carbonate polymer electrolyte with improved interfacial stability for solid-state lithium battery

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Rare Metals 2022年第6期41卷 1889-1898页

作者： Fei Zheng hao-Tong Li yan-Zhen Zheng Dan Wang ning-ning yang Hai-yang Ding Xia Tao Beijing Key Laboratory of Green Recovery and Extractionof Rare and Precious Metals University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China General Research Institute of Nonferrous Metals Beijing 100088China China Automotive Battery Research Institute Co. Ltd.Beijing 101407China

The polyvinyl carbonate(PVC)polymer solid electrolyte can be in-situ generated in the assembled lithium-ion battery(LIBs);however,its rigid characteristic leads to uneven interface contact between electrolyte and *** this work,trimethyl phosphate(TMP)is introduced into the precursor solution for in-situ generation of flexible PVC solid electrolyte to improve the interfacial contact of elec-trolyte and electrodes together with ionic *** PVC-TMP electrolyte exhibits good interface compatibility with the lithium metal anode,and the lithium symmetric battery based on PVC-TMP electrolyte shows no obvious polarization within 1000 h *** a consequence,the initial interfacial resistance of battery greatly decreases from 278Ω(LiFePO_(4)(LFP)/PVC/Li)to 93Ω(LFP/PVC-TMP/Li)at 50℃,leading to an improved cycling stability of the LFP/PVC-TMP/Li *** in-situ preparation of solid electrolyte within the battery is demonstrated to be very significant for commercial application.

关键词： Trimethyl phosphate Solid polymer electrolyte Interface stability Compatibility Lithium ion battery

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Inverse opal manganese dioxide constructed by few-layered ultrathin nanosheets as high-performance cathodes for aqueous zinc-ion batteries

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Nano Research 2019年第6期12卷 1347-1353页

作者： hao ren Jin Zhao Lan yang Qinghua Liang Srinivasan Madhavi Qingyu yan School of Materials Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore Energy Research Institute(ERI@N) Nanyang Technological UniversitySingapore 637553Singapore

Considering the high safety,low-cost and high capacity,aqueous zinc ion batteries have been a potential candidate for energy storage ensuring smooth electricity ***,we have synthesized inverse opal manganese dioxide constructed by few-layered ultrathin nanosheets by a solution template method at mild *** ultrathin nanosheets with the thickness as small as 1 nm are well separated without obvious *** as cathode material for aqueous zinc ion batteries,the few-layered ultrathin nanosheets combined with the inverse opal structure guarantee excellent performance.A high specific discharge capacity of 262.9 mAh·g^-1 is retained for the 100th cycle at a current density of 300 mA·g^-1 with a high capacity retention of 95.6%.A high specific discharge capacity of 121 mAh·g^-1 at a high current density of 2,000 mA·g^-1 is achieved even after 5,000 long-term *** ex-situ X-ray diffraction (XRD) patterns,selected-area electron diffraction (SAED) patterns and high-resolution transmission electron microscopy (HRTEM) results demonstrate that the discharge/charge processes involve the reversible formation of zinc sulfate hydroxide hydrate on the cathode while in-plane crystal structure of the layered bimessite MnO2 could be *** unique structured MnO2 is a promising candidate as cathode material for high capacity,high rate capability and long-term aqueous zinc-ion batteries.

关键词： inverse opal ultrathin few-layered nanosheets MnO2 zinc ion batteries

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Pion transverse-momentum spectrum, elliptic flow, and Hanbury-Brown-Twiss interferometry in a viscous granular source model

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Chinese Physics C 2017年第8期41卷 78-92页

作者： Jing yang Wei-ning Zhang yan-Yu ren School of Physics and Optoelectronic Technology Dalian University of Technology Dalian Liaoning 116024 China Department of Physics Harbin Institute of Technology Harbin Heilongjiang 150006 China

We examine the evolution of quark-gluon plasma（QGP） droplets with viscous hydrodynamics and analyze the pion transverse-momentum spectrum, elliptic flow, and Hanbury-Brown-Twiss（HBT） interferometry in a granular source model consisting of viscous QGP droplets. The shear viscosity of the QGP droplet speeds up and slows down the droplet evolution in the central and peripheral regions of the droplet, respectively. The effect of the bulk viscosity on the evolution is negligible. Although there are viscous effects on the droplet evolution, the pion momentum spectrum and elliptic flow change little for granular sources with and without viscosity. On the other hand,the influence of viscosity on HBT radius Rout is considerable. It makes Rout decrease in the granular source *** determine the model parameters of granular sources using the experimental data of pion transverse-momentum spectrum, elliptic flow, and HBT radii together, and investigate the effects of viscosity on the model parameters. The results indicate that the granular source model may reproduce the experimental data of pion transverse-momentum spectrum, elliptic flow, and HBT radii in heavy-ion collisions of Au-Au at√s（NN）=200 GeV and Pb-Pb at√s（NN） =2.76 Te V in different centrality intervals. The viscosity of the droplet leads to an increase in the initial droplet radius and a decrease of the source shell parameter in the granular source model.

关键词： high-energy heavy-ion collisions pion interferometry elliptic flow granular source viscous hydrodynamics

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