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Chinese Chemical Letters 2006年第10期17卷 1369-1372页

作者： Gui Yun XU Yang chen ru xian chen Institute of Chemistry Chinese Academy of Sciences Beijing 100080 Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences Beijing 100050

A new polysaccharide was extracted and purified from the roots of Angelica sinensis （Oliv） Diels （ASD）. Its composition and linkage was elucidated by selective hydrolysis and GC/MS analysis of its derivatives. The polysaccharide was made of → 1） Fruf（2→and→6） Glcp （l→as its backbone with highly branched structure. To our best knowledge, this is the first report of the fructose residue in polysaccharides from the roots of the ASD.

关键词： Selective hydrolysis fructofuranosyl backbone GC/MS

Effects of Combined Treatment with Sansanmycin and Macrolides on Pseudomonas aeruginosa and Formation of Biofilm

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Biomedical and Environmental Sciences 2009年第2期22卷 170-177页

作者： YUE LI YUN-YING XIE ru-xian chen HONG-ZHANG XU GUO-JI ZHANG JIN-ZHE LI AND XIAO-MIAN LI Department of Microbiology Tianjin Medical University Tianjin 300070 China Department of Microbiology and Biochemical Pharmacy Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences Beijing 100050 China

Objective To observe the effects of combined treatment with sansanmycin and macrolides on Pseudomonas aeruginosa and formation of biofilm. Methods Micro-dilution method was used to determine the minimal inhibitory concentrations （MICs） of sansanmycin, gentamycin, carbenicillin, polymyxin B, roxithromycin, piperacillin, and tazobactam. PAl and PA27853 biofilms were observed under optical microscope after staining and under SEM after treatment with sansanmycin at different dosages and combined treatment with sansanmycin and roxithromycin. Viable bacteria in PAl and PA27853 biofilms were counted after treatment with sansanmycin at different dosages or combined treatment with sansanmycin and roxithromycin. Results The MIC of sansanmycin was lower than that of gentamycin and polymyxin B, but was higher than that of carbenicillin. Roxithromycin enhanced the penetration of sansanmycin to PAl and PA27853 strains through biofilms. PAl and PA27853 biofilms were gradually cleared with the increased dosages of sansanmycin or with the combined sansanmycin and roxithromycin. Conclusion Sub-MIC levels of roxithromycin and sansanmycin substantially inhibit the generation of biofilms and proliferation of bacteria. Therefore, combined antibiotics can be used in treatment of intractable bacterial infection.

关键词： Sansanmycin Macrolides Pseudomonas aeruginosa Biofilm

Synthesis of Tetra-Schiff Base Macrocyclic Compound Containing Benzo-12-crown-4

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Chinese Chemical Letters 2002年第6期13卷 513-514页

作者： Bin SUN Jun ru chen Hua chen Yao Zhong LI xian Jun LI Department of Chemistry Sichuan UniversityChengdu 610064

Tetra-Schiff base macrocyclic compound containing benzo-12-crown-4 was synthesized via condensation of 2, 6-diformyl-4-methyl-phenol with 4, 5- diaminobenzo-12C- 4 promoted by proton. The compound was characterized b... 详细信息

关键词： Schiff base crown macrocyclic compound

Fullerene bisadduct stabilizers:The effect of different addition positions on inhibiting the autocatalytic decomposition of nitrocellulose absorbed nitroglycerin

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Defence Technology（防务技术） 2021年第6期17卷 1944-1953页

作者： Ling Liao Bo Jin Zhi-cheng Guo Fei xian chen-jie Hou ru-fang Peng State Key Laboratory of Environment-friendly Energy Materials School of Materials Science and EngineeringSouthwest University of Science and TechnologySichuanMianyang621010China

To explore the effect of different positions and number of pyrrolidine bound to the carbon cage on the stabilization effect of fulleropyrrolidine derivatives to nitrocellulose(NC)/nitroglycerine(NG),we synthesized N-(4-methoxy)phenylpyrrolidine-C_(60) and four different of bis(N-(4-methoxy)phenylpyrrolidine)-C_(60) compounds through Prato *** structures were characterized by UVevis,^(1)H NMR,^(13)C NMR,high-resolution mass spectroscopy,and single-crystal X-ray *** stabilization effect to NC/NG were investigated using differential scanning calorimetry,methyl violet,vacuum stabilization effect,weight loss,and accelerating rate calorimeter *** results indicated these compounds had excellent stabilization effect to NC/*** stabilization effect of the fulleropyrrolidine bisadducts to NC/NG is significantly better than that of fulleropyrrolidine monoadduct and C_(60).Moreover,the position where pyrrolidine binds to fullerene in fulleropyrrolidine bisadducts is different,and its stabilization effect to NC is also *** stabilization effect order of different bisadduct isomers to nitrocellulose is as follows:e-edge>trans-2>cis-2>*** paramagnetic resonance(EPR)and FT-IR were used to study the stabilization mechanism of fulleropyrrolidine derivatives to NC/*** EPR results also show that fulleropyrrolidine bisadducts with different addition sites have different abilities to absorb nitroxide,and their ability is better than that of the monoadduct and C_(60),which is consistent with the results of stabilization effect performance test.

关键词： Fulleropyrrolidine bisadducts Stabilization effect Nitrocellulose/nitroglycerine

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锁骨轴位改良投照技术的临床应用

实用医技杂志 2006年第4期13卷 504-505页

作者：郑卫东庄儒耀陈显恩郑邦豪汕头大学医学院第一附属医院广东汕头515041

目的：探讨锁骨骨折轴位改良投照技术的临床应用。方法：采用仰卧前后位，将球管向头侧倾斜30°角～40°角，对准患侧锁骨中点进行投照点片。结果：15例锁骨骨折伤患，采用常规后前位投照，仅3例明显显示骨折端前后移位和／或向后成角X... 详细信息

目的：探讨锁骨骨折轴位改良投照技术的临床应用。方法：采用仰卧前后位，将球管向头侧倾斜30°角～40°角，对准患侧锁骨中点进行投照点片。结果：15例锁骨骨折伤患，采用常规后前位投照，仅3例明显显示骨折端前后移位和／或向后成角X线征；1例小儿未被发现骨折；其余11例骨折伤患显示骨折端对位对线良好。而采用改良轴位投照，原诊对位对线良好的11例患者，7例出现明显前后移位和／或成角的X线征；1例原未见骨折的小儿伤患，显示青枝骨折X线征。结论：锁骨骨折投照中，常规后前位投照不能全面反映骨折情况，应用锁骨轴位改良投照技术，能够较明确反映锁骨骨折骨折线对位对线情况。提高锁骨骨折诊断价值。

关键词：锁骨骨折 X线

Track correlation algorithm based on CNN-LSTM for swarm targets

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Journal of Systems Engineering and Electronics 2024年第2期35卷 417-429页

作者： chen Jinyang WANG Xuhua chen xian Research Institute for National Defense Engineering Academy of Military SciencesLuoyang 471023China Information Engineering University Zhengzhou 450001China School of Computer Science and Technology Xidian UniversityXi’an 710071China

The rapid development of unmanned aerial vehicle(UAV) swarm, a new type of aerial threat target, has brought great pressure to the air defense early warning system. At present, most of the track correlation algorithms only use part of the target location, speed, and other information for *** this paper, the artificial neural network method is used to establish the corresponding intelligent track correlation model and method according to the characteristics of swarm ***, a route correlation method based on convolutional neural networks (CNN) and long short-term memory (LSTM)Neural network is designed. In this model, the CNN is used to extract the formation characteristics of UAV swarm and the spatial position characteristics of single UAV track in the formation,while the LSTM is used to extract the time characteristics of UAV swarm. Experimental results show that compared with the traditional algorithms, the algorithm based on CNN-LSTM neural network can make full use of multiple feature information of the target, and has better robustness and accuracy for swarm targets.

关键词： track correlation correlation accuracy rate swarm target convolutional neural network(CNN) long short-term memory(LSTM)neural network

Development of a seven-cell S-band standing-wave RF-deflecting cavity for Tsinghua Thomson scattering X-ray source

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Nuclear Science and Techniques 2021年第4期32卷 20-29页

作者： xian-Cai Lin Hao Zha Jia-ru Shi Liu-Yuan Zhou Shuang Liu Jian Gao Huai-Bi chen Department of Engineering Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Particle and Radiation Imaging(Tsinghua University) Ministry of EducationBeijing 100084China

A 2856-MHz,π-mode,seven-cell standingwave deflecting cavity was designed and fabricated for bunch length measurement in Tsinghua Thomson scattering X-ray source(TTX)*** cavity was installed in the TTX and provided a deflecting voltage of 4.2 MV with an input power of 2.5 *** length diagnoses of electron beams with energies up to 39 MeV have been *** this article,the RF design of the cavity using HFSS,fabrication,and RF test processes are ***-power operation with accelerated beams and calibration of the deflecting voltage are also presented.

关键词： Deflecting RF cavity Standing wave Bunchlength measurement Thomson X-ray source

A compact X-band backward traveling-wave accelerating structure

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Nuclear Science and Techniques 2024年第5期35卷 13-29页

作者： xian-Cai Lin Hao Zha Jia-ru Shi Qiang Gao Fang-Jun Hu Qing-Zhu Li Huai-Bi chen Department of Engineering Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Particle and Radiation Imaging(Tsinghua University) Ministry of EducationBeijing 100084China

Very high-energy electrons(VHEEs)are potential candidates for FLASH radiotherapy for deep-seated *** proposed a compact VHEE facility based on an X-band high-gradient high-power *** this study,we investigated and realized the first X-band backward traveling-wave(BTW)accelerating structure as the buncher for a VHEE facility.A method for calculating the parameters of single cell from the field distribution was introduced to simplify the design of the BTW ***-domain circuit equations were applied to calculate the transient beam parameters of the buncher in the unsteady state.A prototype of the BTW structure with a thermionic cathode-diode electron gun was designed,fabricated,and tested at high power at the Tsinghua X-band high-power test *** structure successfully operated with 5-MW microwave pulses from the pulse compressor and outputted electron bunches with an energy of 8 MeV and a pulsed current of 108 mA.

关键词： Backward traveling-wave accelerating structure Equivalent circuit model High-power test Very high-energy electron radiotherapy

Population evolution at the prefecture-level city scale in China:Change patterns and spatial correlations

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Journal of Geographical Sciences 2022年第7期32卷 1281-1296页

作者： xian Yue chen Mingxing Key Laboratory of Regional Sustainable Development Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China College of Resource and Environment University of Chinese Academy of SciencesBeijing 100049China

China has entered a new stage of high-quality ***,it is critical to grasp the latest population distribution and *** mean-variance grading,Moran’s index,and the Theil index,this study compared the differences in population changes between 2010–2020 and 2000–2010 at the prefecture-level city scale based on census data to analyze the new trends in population *** found that:(1)New growth poles of the population are inland provincial capitals,forming rapid-growing zones together with coastal urban *** growth in over 60%of the cities in the northern coastal urban agglomeration has slowed.(2)The scope of population loss in inland areas is constantly *** the northeastern part of China,92.7%of the cities have lost population,making this a typical population loss area.(3)Population shrinkage in the northeastern region and growth in the Pearl River Delta urban agglomeration show diffusion characteristics,while population patterns around the provincial capital are in a polarized stage.(4)The Theil index of population distribution increased,with 83.91%of differences coming from between groups,indicating that the gap between cities of different sizes has further *** study provides scientific support for the coordinated promotion of nearby and remote urbanization.

关键词： population distribution agglomeration and decentralization pattern change nearby urbanization prefecture-level city

Energy Expenditure of Trotting Gait Under Different Gait Parameters

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Chinese Journal of Mechanical Engineering 2017年第4期30卷 943-950页

作者： xian-Bao chen Feng Gao State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai 200240 China

Robots driven by batteries are clean, quiet, and can work indoors or in space. However, the battery endurance is a great problem. A new gait parameter design energy saving strategy to extend the working hours of the quadruped robot is proposed. A dynamic model of the robot is established to estimate and analyze the energy expenditures during trotting. Given a trotting speed, opti- mal stride frequency and stride length can minimize the energy expenditure. However, the relationship between the speed and the optimal gait parameters is nonlinear, which is difficult for practical application. Therefore, a simplified gait parameter design method for energy saving is pro- posed. A critical trotting speed of the quadruped robot is found and can be used to decide the gait parameters. When the robot is travelling lower than this speed, it is better to keep a constant stride length and change the cycle period. When the robot is travelling higher than this speed, it is better to keep a constant cycle period and change the stride length. Simulations and experiments on the quadruped robot show that by using the proposed gait parameter design approach, the energy expenditure can be reduced by about 54% compared with the 100 mm stride length under 500 mm/s speed. In general, an energy expenditure model based on the gait parameter of the quadruped robot is built and the trotting gait parameters design approach for energy saving is proposed.

关键词： Quadruped robot Energy expenditure Gait Bezier curve