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Chinese Chemical Letters 2008年第3期19卷 261-263页

作者： jia Di Huang xiang Ping Hu Zhuo Zheng Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 PR China Graduate School of Chinese Academy of Sciences Beijing 100039 PR China

A novel chiral phosphine-triazine ligand was synthesized from chiral α-phenylethylamine through a three-step procedure. In a model reaction of Pd-catalyzed allylic alkylation of rac-1,3-diphenylprop-2-en-1-y1 pivalat... 详细信息

关键词： Synthesis α-Phenylethylamine Phosphine-triazine ligand Pd-catalyzed allylic alkylation

Preparation and tensile properties of DD5 single crystal castings

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International Journal of Minerals,Metallurgy and Materials 2016年第6期23卷 683-690页

作者： xiang-feng Liang Yu-tao Zhao Zhi-hong jia Chi Zhang School of Material Science and Engineering Jiangsu University

The preparation procedure of DD5 single crystal castings was optimized. The microstructure characteristics of DD5 single crystal superalloy were investigated by microstructure observation and segregation behavior examination. The results show that the grain orientation is optimized by constraining the spiral crystallizer in [001] orientation and spatial scale. Also, the γ＇ phase of inter-dendrites is larger and more irregular than that in dendrite arms. High temperature tensile tests of DD5 single crystal castings exhibit that the peak stress increases with increasing temperature, while the area reduction shows an opposite trend, when the temperature is below 800℃; meanwhile, when the temperature is between 800℃ and 1000℃, the fracture stress of the alloy is the same as the peak stress. The fracture mode changes from shear to ductile with increasing temperature from 600℃ and 1000℃.

关键词： superalloys single crystals segregation tensile properties alloy preparation castings

The Coupled Effects of Dryness and Non-condensable Gas Content of Geothermal Fluid on the Power Generation Potential of an Enhanced Geothermal System

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Acta Geologica Sinica(English Edition) 2021年第6期95卷 1948-1957页

作者： LI Tailu LI Xuelong jia Yanan GAO xiang School of Energy and Environmental Engineering Hebei University of TechnologyTianjin 300401China Tian Architectural Design Company Limited Tianjin 300384China

The Enhanced Geothermal System(EGS) is a recognized geothermal exploitation system for hot dry rock(HDR), which is a rich resource in China. In this study, a numerical simulation method is used to study the effects of geothermal fluid dryness and non-condensable gas content on the specific enthalpy of geothermal fluid. Combined with the organic Rankine cycle(ORC), a numerical model is established to ascertain the difference in power generation caused by geothermal fluid dryness and non-condensable gas content. The results show that the specific enthalpy of geothermal fluid increases with the increase of geothermal fluid temperature and geothermal fluid dryness. If the dryness of geothermal fluid is ignored, the estimation error will be large for geothermal fluid enthalpy. Ignoring non condensable gas will increase the estimation of geothermal fluid enthalpy, so the existence of the non-condensable gas tends to reduce the installed capacity of a geothermal power plant. Additionally, both mass flow of the working medium and net power output of the ORC power generation system are increased with increasing dryness of geothermal fluid, however there is some impact of geothermal fluid dryness on thermal efficiency.

关键词： hot dry rock geothermal fluid dryness non-condensable gas organic Rankine cycle

Rapid Shape Memory and p H-modulated Spontaneous Actuation of Dopamine Containing Hydrogels

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Chinese Journal of Polymer Science 2017年第10期35卷 1297-1306页

作者： Jie-xin Liao jia-he Huang 王涛 Wei-xiang Sun 童真 Research Institute of Materials Science South China University of Technology Guangzhou 510640 China State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 China

The dopamine containing hydrogels with rapid responsive shape memory capability were synthesized by a one-pot method. The temporary shape of hydrogel was fixed within 20 s in Na OH solution by the tris-complex crosslinking of metalligand complex between Fe3＋ ions and catechol groups, while the permanent shape was recovered completely in HCl solution within 60 s upon the change from tris-complex to mono-complex. The hydrogel showed unique spontaneous actuation behavior. It could curl spontaneously without further external force deformation when immersed in Na OH solution again after the first shape recovery in HCl solution. This might be attributed to the competitive result of swelling and additional tris-complex crosslinking formation when immersed in Na OH solution. In addition, the hydrogels also had proper modulus, elongation ratio and tensile strength. Such hydrogel provides a new candidate material for designing soft actuators and robots modulated with spontaneous actuating.

关键词： DNA hydrogel duplex supramolecular cytosine assemble assembly motif intermolecular acrylamide

Underwater sonar target imaging via compressed sensing with M sequences

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Science China Earth Sciences 2016年第12期59卷 111-120页

作者： Huichen YAN jia XU xiang-Gen XIA Xudong ZHANG Teng LONG Department of Electronic Engineering Tsinghua University School of Information and Electronics Beijing Institute of Technology Department of Electrical and Computer Engineering University of Delaware

Due to the low sound propagation speed, the tradeoff between high azimuth resolution and wide imaging swath has severely limited the application of sonar underwater target imaging. However, based on compressed sensing(CS) technique, it is feasible to image targets with merely one pulse and thus avoid the above tradeoff. To investigate the possible waveforms for CS-based underwater imaging, the deterministic M sequences widely used in sonar applications are introduced in this paper. By analyzing the compressive matrix constructed from M sequences, the coherence parameter and the restricted isometry property(RIP) of the matrix are derived. Also, the feasibility and advances of M sequence are demonstrated by being compared with the existing Alltop sequence in underwater CS imaging framework. Finally, the results of numerical simulations and a real experiment are provided to reveal the effectiveness of the proposed signal.

关键词： sonar high-resolution imaging compressed sensing M sequence coherence parameter restricted isometry property

Numerical and experimental studies on impact dynamics of a planar flexible multibody system

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Acta Mechanica Sinica 2010年第4期26卷 635-642页

作者： Fu-xiang Dong jia-Zhen Hong Kun Zhu Zheng-Yue Yu Department of Engineering Mechanics Shanghai Jiaotong University 200240 Shanghai China

In this paper a computational methodology on impact dynamics of the flexible multibody system is presented. First, the floating frame of reference approach and nodal coordinates on the basis of finite element formulation are used to describe the kinematics of planar deformable bodies. According to the kinematic description of contact conditions, the contact constraint equations of planar flexible bodies are derived. Based on the varying topology technique the impact dynamic equations for a planar multibody system are established. Then the initial conditions of the equations in each contact stage are determined according to the discontinuity theory in continuum mechanics. The experiments between the aluminum rods are performed to check the correctness of the proposed method. Through the comparison between the numerical and experimental results the proposed method is validated. Experimental results also show that the impulse momentum method cannot accurately predict the complex impact dynamic phenomena and the continuous model may lead to a serious error when used to simulate the impact problems with significant wave propagation effects.

关键词： Flexible multibody system Impact dynamics Appending constraint method (ACM) Impact experiments

Syntheses and Structural Researches of Yb^(3+) Complexes with Nitrilotriacetic Acids──Nine-coordinate K_3[Yb(nta)_2(H_2O)]·5H_2O and Eight-coordinate Na_3[Yb(nta)_2]·6H_2O Complexes

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Chemical Research in Chinese Universities 2003年第2期19卷 145-150页

作者： WANG Jun ZHANG xiang dong jia Wei guo LI Hui fang Department of Chemistry Liaoning UniversityShenyang 110036P.R.China

Yb 3+ complexes with two nitrilotriacetic acid molecules were prepared and their compositions were determined as K 3[Yb(nta) 2(H 2O)]·5H 2O and Na 3[Yb(nta) 2]·6H 2O by elemental analyses. Their structures were characterized by single crystal X ray diffraction analyses. In complex K 3[Yb(nta) 2(H 2O)]·5H 2O, the YbN 2O 7 part forms a nine coordinate monocapped square antiprismatic structure. In complex Na 3[Yb(nta) 2]·6H 2O, the YbN 2O 6 part forms an eight coordinate square antiprismatic structure. It can be seen that the outer cations (K + and Na +) greatly affect the coordination number and coordinate structure from these results.

关键词： Yb^(3+) complex Nitrilotriacetic acid Crystal structure

Microstructural and textural evolutions in multilayered Ti/Cu composites processed by accumulative roll bonding

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Journal of Materials Science & Technology 2019年第6期35卷 1165-1174页

作者： Shuang jiang Ru Lin Peng Nan jia xiang Zhao Liang Zuo Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education) School of Material Science and Engineering Northeastern UniversityShenyang 110819 China Department of Mechanical Engineering Linkoping University Linkoping 58183 Sweden

Ti/Cu multilayered composites were fabricated via accumulative roll bonding(ARB). During codeformation of the constituent metals, the hard Ti layers necked preferentially and then fragmented with the development of shear bands. Transmission electron microscopy showed that with increasing ARB cycles, grains in Ti were significantly refined even though dynamic recrystallization has occurred. For Cu the significant grain refinement was only found within the shear banded region when the composite was processed after five ARB cycles. Due to the diffusion of Cu atoms into Ti at the heterophase interfaces, amorphization with a width less than 10 nm was identified even in the composite processed by one cycle. At higher ARB cycles, the width of amorphous region increased and intermetallic compounds CuTi appeared from the region. The lattice defects introduced at the heterophase interfaces under roll bonding was responsible for the formation of the nano-scaled compounds. X-ray diffraction showed that an abnormal {1120} fiber texture was developed in Ti layers, while significant brass-type textures were developed in Cu layers. Some orientations along the {1120} fiber favored the prismatic slip for *** tests revealed the elevated strength without a substantial sacrifice of ductility in the composites during ARB. The unique mechanical properties were attributed to the significantly refined grains in individual metals, the good bonding between the constituent metals, as well as the development of an abnormal {1120} fiber texture in Ti layers.

关键词： Titanium/copper multilayered composite Accumulative roll bonding Microstructure Texture Mechanical properties

IN SITU OBSERVATION OF MELTING AND CRYSTALLIZATION BEHAVIORS OF POLY(ε-CAPROLACTONE) ULTRA-THIN FILMS BY AFM TECHNIQUE

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Chinese Journal of Polymer Science 2013年第9期31卷 1321-1328页

作者： Cong-de Qiao Shi-chun jiang xiang-ling Ji Li-jia An School of Material Science & Engineering Shandong Polytechnic University School of Material Science & Engineering Tianjin University State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences

The melting and crystallization behaviors of poly（e-caprolactone）（PCL） ultra-thin films with thickness from 15 ran to 8 nm were studied by AFM technique equipped with a hot-stage in real-time. It was found that melting can erase the spherulitic structure for polymer film with high thickness. However, annealing above the melting point can not completely erase the tree-like structure for the thinner polymer film. Generally, the structure formation of thin polymer films of PCL is controlled not only by melting and crystallization but also by dewetting during thermal annealing procedures, and dewetting predominates in the structure formation of ultra-thin films. However, the presence of tree-like morphology at 75 ℃ may be due to the strong interaction between PCL and mica surface, which may stick the PCL chains onto the mica surface during thermal annealing process. Moreover, the growth of the dendrites was investigated and it was found that crystallization is followed from a dewetted sample, and the branches did not grow with the stems. The crystallization of polymer in the ultra- thin films is a diffusion-controlled process. Both melting and crystallization behaviors of PCL in thin films are influenced by film thickness.

关键词： PCL Ultra-thin film Melting Crystallization Dewetting.

FCOS-LSC:A Novel Model for Green Fruit Detection in a Complex Orchard Environment

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Plant Phenomics 2023年第3期5卷 546-563页

作者： Ruina Zhao Yujie Guan Yuqi Lu Ze Ji xiang Yin Weikuan jia School of Information Science and Engineering Shandong Normal UniversityJinan 250358China School of Engineering Cardiff UniversityCardiff CF243AAUK School of Agricultural Engineering and Food Science Shandong University of TechnologyZibo 255000China Key Laboratory of Facility Agriculture Measurement and Control Technology and Equipment of Machinery Industry Zhenjiang 212013China

To better address the difficulties in designing green fruit recognition techniques in machine vision systems,a new fruit detection model is *** model is an optimization of the FCOS(full convolution one-stage object detection)algorithm,incorporating LSC(level scales,spaces,channels)attention blocks in the network structure,and named *** method achieves efficient recognition and localization of green fruit images affected by overlapping occlusions,lighting conditions,and capture ***,the improved feature extraction network ResNet50 with added deformable convolution is used to fully extract green fruit feature *** feature pyramid network(FPN)is employed to fully fuse low-level detail information and high-level semantic information in a cross-connected and top-down connected ***,the attention mechanisms are added to each of the 3 dimensions of scale,space(including the height and width of the feature map),and channel of the generated multiscale feature map to improve the feature perception capability of the ***,the classification and regression subnetworks of the model are applied to predict the fruit category and bounding *** the classification branch,a new positive and negative sample selection strategy is applied to better distinguish supervised signals by designing weights in the loss function to achieve more accurate fruit *** proposed FCOS-LSC model has 38.65M parameters,38.72G floating point operations,and mean average precision of 63.0%and 75.2%for detecting green apples and green persimmons,*** summary,FCOS-LSC outperforms the state-of-the-art models in terms of precision and complexity to meet the accurate and efficient requirements of green fruit recognition using intelligent agricultural ***,FCOS-LSC can be used to improve the robustness and generalization of the green fruit detection models.

关键词： connected designing weights