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Hydrosilylation of olefins over rhodium complex anchored over thioether-functionalized MCM-41

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Chinese Chemical Letters 2010年第11期21卷 1310-1313页

作者： Lig Fang zha.Wei Sen Yang,wen Yan Hao,Ming Zhong Cai Department of Chemistry,Jiangxi Normal University,Nanchang 330022,China [a] Department of Chemistry Jiangxi Normal University Nanchang 330022 China

The hydrosilylation of alkenes with triethoxysilane has been achieved at 120 C in the presence of 0.01 mol%of thioetherfunctionalized MCM-41 anchored rhodium complex,affording the corresponding addition products in 68-91%*** supported rhodium complex can be reused several times without noticeable loss of *** system not only solves the basic problems of catalyst separation and recovery,but also avoids the use of phosphine ligands.

关键词： Supported rhodium catalyst Sulfur rhodium complex Hydrosilylation MCM-41 Heterogeneous catalysis

A Model for Estimating Total Forest Coverage with Ground-Based Digital Photography

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Pedosphere 2010年第3期20卷 318-325页

作者： GU Zhu-Jun ZENG zhi-Yuan SHI Xue-Zheng LI Lin D. C. WEINDORF zha.Yong YU Dong-Sheng LIU YongoMei State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of SciencesNanjing 210008 (China) School of Bio-Chemical and Environmental Engineering Nanjing Xiaozhuang University Nanjing 211171 (China) College of Geography Science Nanjing Normal University Nanjing 210097 (China) Department of Earth Sciences Indiana University-Purdue University Indianapolis IN 46202 (USA) LSU AgCenter Baton Rouge LA 70803 (USA)

Vegetation fractional coverage (VFC) is one of the key indicators of vegetation distribution. In the work a measurement-based model was developed to derive total forest VFC (TG) as well as the VFC of trees (T) and shrub-grasses (G) separately in a subtropical forest area in Nanjing, China. Both upward and downward photographs were taken with a digital camera in 72 quadrats (10 m × 10 m each). Fifteen models were established and validated. Models jointly using both T and G performed better than those using the T and G separately. The best model, TG = T + G- 1.134 × T × G- 0.025 (R2 = 0.9115, P < 0.01, root mean squared error = 0.0789), is recommended for application. This model provides a good way to obtain total forest VFC values through taking tree and shrub-grass photos on ground below tree canopy rather than above tree canopy.

关键词： digital camera 2-layer photography shrub-grasses trees

Surrounding rock control of gob-side entry driving with narrow coal pillar and roadway side sealing technology in Yangliu Coal Mine

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International Journal of Mining Science and Technology 2017年第5期27卷 819-823页

作者： zha.wenhua Shi Hao Liu San Kang Changhao Key Laboratory of Safe and Effective Coal Mining School of Mining and Safety EngineeringAnhui University of Science&TechnologyMinistry of EducationHuainan 232001China

Gob-side entry driving can increase coal recovery ratio, and it is implied in many coal mines. Based on geological condition of 10416 working face tailentry in Yangliu Coal Mine, the surrounding rock deformation characteristics of gob-side entry driving with narrow coal pillar is analysed, reasonable size of coal pillar and reasonable roadway excavation time after mining are achieved. Surrounding rock control technology and effective roadway side sealing technology are proposed and are taken into field practice. The results showed that a safer and more efficient mining of working face can be achieved. In addition, results of this paper also have important theoretical significance and valuable reference for surrounding rock control technology of gob-side entry driving with narrow coal pillar under special geological condition.

关键词： Narrow coal pillar Gob-side entry driving Surrounding rock control Roadway side sealing technology

Structural Stability and Half Metallic Features of Zn_(0.5)Cr_(0.5)S under Pressure

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Journal of Materials Science & Technology 2014年第3期30卷 234-238页

作者： Yuhong Huang Wanqi Jie Yan Zhou Gangqiang zha State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University

Spin-polarized first-principle was performed to study the structural stability and the electronic states of Cr doped ZnS with the Cr component of 50% in zincblende （ZB）, wurtzite （W） and rocksalt （RS） structures under pressure. The results show that the zincblende and wurtzite structures become unstable under low pressures of about 4.68 and 9.61 GPa, respectively, but the rocksalt structure can be maintained up to an extremely high pressure of about 32.92 GPa. Both zincblende and wurtzite ***.5S display half metallic features under pressure, while rocksalt *** exhibits metallic feature. The half metallic features can be ascribed to the stronger interactions between S-3p and Cr-3d states and the metallic feature is due to the higher crystal symmetry of rocksalt Zn0.5Cr0.5S. These results can provide helpful guidance for Cr doped ZnS to be used in spintronic devices.

关键词： Structural stability Half metallic features Electronic properties Zn0.5Cr0.5S Pressure

Predicting the Catalytic Activity of Surface Oxidation Reactions by Ionization Energies

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CCS Chemistry 2020年第4期2卷 262-270页

作者： Shenjun zha.zhi-Jian zha. Sai Chen Sihang Liu Tao Liu Felix Studt Jinlong Gong Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityCollaborative Innovation Center of Chemical Science and EngineeringTianjin 3000722Institute of Catalysis Research and TechnologyKarlsruhe Institute of Technology76344 Eggenstein-Leopoldshafen3Institute for Chemical Technology and Polymer ChemistryKarlsruhe Institute of Technology76131 Karlsruhe

Developing a descriptor to understand the reactivity of a catalyst is critical in achieving the rational design of heterogeneous ***,the descriptor should be simple,predictive,as well as applicable to diverse types of *** paper describes the development of a descriptor that could meet such ideal requirements based on its element-specific fundamental property,ionization *** results indicated that ionization energies could be utilized to describe successfully the adsorption energies of oxygen(O*)and hydroxyl(OH*)groups on various ***,we constructed a bond formation scheme to parse this phenomenon.

关键词： ionization energy scaling relationship reactivity descriptor charge transfer bond formation scheme

Particle breakage evolution of coral sand using triaxial compression tests

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第2期13卷 321-334页

作者： Gang Wang zha.nan Wang Qinguo Ye Jingjing zha Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing400045China School of Civil Engineering Chongqing UniversityChongqing400045China National Joint Engineering Research Center for Geohazards Prevention in the Reservoir Areas Chongqing400045China

Particle breakage continuously changes the grading of granular materials and has a significant effect on their mechanical *** the evolution pattern of particle breakage is valuable for development and validation of constitutive models for crushable materials.A series of parallel triaxial compression tests along the same loading paths but stopped at different axial strains were conducted on two coral sands with different particle sizes under drained and undrained *** tested specimens were carefully sieved to investigate the intermediate accumulation of particle breakage during the loading *** test results showed that under both drained and undrained conditions,particle breakage increases continuously with increasing axial strain but exhibits different accumulating patterns,and higher confining pressures lead to greater particle *** on the test results,the correlations between particle breakage and the stress state as well as the input energy were *** results demonstrated that either the stress state or input energy alone is inadequate for describing the intermediate process of particle breakage ***,based on experimental observation,a path-dependent model was proposed for particle breakage evolution,which was formulated in an incremental form and reasonably considers the effects of the past breakage history and current stress state on the breakage *** path-dependent model successfully reproduced the development of particle breakage during undrained triaxial compression using the parameters calibrated from the drained tests,preliminarily demonstrating its effectiveness for different stress paths.

关键词： Particle breakage Coral sand Triaxial compression Relative breakage Breakage model

Ranking approach of cross-efficiency based on improved TOPSIS technique

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Journal of Systems Engineering and Electronics 2011年第4期22卷 604-608页

作者： Jie Wu Jiasen Sun Yong zha.Liang Liang School of Management University of Science and Technology of China Hefei 230026 R R. China

The cross-efficiency evaluation method is reviewed which is developed as a data envelopment analysis （DEA） extensive tool. The cross-efficiency evaluation method is utilized to identify the decision making unit （DMU） with the best practice and to rank the DMUs by their respective cross-efficiency scores. The main drawbacks of the cross-efficiency evaluation method when the ultimate average cross-efficiency scores are used to evalu- ate and rank the DMUs are also pointed out. With the research gap, an improved technique for order preference by similarity to ideal solution （TOPSIS） is introduced to rank the crossfficiency by eliminating the average assumption. Finally, an empirical example is illustrated to examine the validity of the proposed method.

关键词： data envelopment analysis (DEA) cross-efficiency,improved technique for order preference by similarity to ideal solu-tion (TOPSIS) decision making unit (DMU).

Simulation of dual transponder carrier ranging measurements

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第10期10卷 1395-1403页

作者： Xiang-yu zha.Xiao-jun JIN Zhong-he JIN Department of lnformation Science and Electronic Engineering Zhejiang University Hangzhou 310027 China

The most dominant error source for microwave ranging is the frequency instability of the oscillator that generates the carrier phase signal. The oscillator noise is very difficult to filter due to its extremely low frequency. A dual transponder carrier ranging method can effectively minimize the oscillator noise by combing the reference phase and the to-and-fro measurement phase from the same single oscillator. This method does not require an accurate time tagging system, since it extracts phases on the same satellite. This paper analyzes the dual transponder carrier ranging system by simulation of the phase measurements with comprehensive error models. Both frequency domain and time domain noise transfer characteristics were simulated to compare them with dual one-way ranging. The simulation results in the two domains conformed to each other and demonstrated that a high level of accuracy can also be achieved by use of the dual transponder carder ranging system, with relatively simple instruments.

关键词： Dual transponder carrier ranging Dual one-way ranging Oscillator noise Transfer characteristic

Preparing cyclic polymers at high concentrations via self-folding cyclization technique by adjusting the contents of hydrophilic units in linear precursors

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Chinese Chemical Letters 2024年第2期35卷 283-288页

作者： Hao zha.Zuowei Wang Chao Liu Chunyan Hong Department of Polymer Science and Engineering University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China

Cyclic polymers are a class of polymers that feature endless topology,and the synthesis of cyclic polymers has attracted the attention of many ***,cyclic polymers were efficiently constructed by self-folding cyclization technique at high *** poly((oligo(ethylene glycol)acrylate)-co-(dodecyl acrylate))(P(OEGA-co-DDA))precursors with different ratios of hydrophilic and hydrophobic moieties were synthesized by reversible addition-fragmentation chain transfer(RAFT)polymerization using a bifunctional chain transfer agent with two anthryl end *** amphiphilic linear precursors underwent the self-folding process to generate polymeric nanoparticles in *** irradiating the aqueous solution of the nanoparticles with 365 nm UV light,cyclic polymers were synthesized successfully via coupling of anthryl *** effects of the ratios of hydrophilic and hydrophobic moieties in linear P(OEGA-co-DDA)copolymers and polymer concentration on the purity of the obtained cyclic polymers were explored in detail via ^(1)H nuclear magnetic resonance(^(1)H NMR),dynamic light scattering(DLS),UV‒visible(vis)analysis,three-detection size exclusion chromatography(TD-SEC)and transmission electron microscopy(TEM).It was found that by adjusting the content of the hydrophilic segments in linear precursors,single chain polymeric nanoparticles(SCPNs)can be generated at high polymer ***,cyclic polymers with high purity can be constructed *** method overcomes the limitation of traditional ring-closure method,which is typically conducted in highly dilute conditions,providing an efficient method for the scalable preparation of cyclic polymers.

关键词： Cyclic polymers Self-folding cyclization technique Single chain polymeric nanoparticles RAFT polymerization Direct visualization