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Vibration analysis of piezoelectric sandwich nanobeam with flexoelectricity based on nonlocal strain gradient theory

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Applied Mathematics and Mechanics(English Edition) 2020年第6期41卷 859-880页

作者： shan zeng Kaifa WANG Baolin WANG Jinwu WU Jiangxi Key Laboratory of Micro Aeroengine School of Aircraft EngineeringNanchang Hangkong UniversityNanchang 330063China Graduate School at Shenzhen Harbin Institute of TechnologyHarbin 150001China School of Engineering Western Sydney UniversityPenrithNSW 2751Australia

A nonlocal strain gradient theory(NSGT) accounts for not only the nongradient nonlocal elastic stress but also the nonlocality of higher-order strain gradients,which makes it benefit from both hardening and softening effects in small-scale *** this study, based on the NSGT, an analytical model for the vibration behavior of a piezoelectric sandwich nanobeam is developed with consideration of flexoelectricity. The sandwich nanobeam consists of two piezoelectric sheets and a non-piezoelectric core. The governing equation of vibration of the sandwich beam is obtained by the Hamiltonian principle. The natural vibration frequency of the nanobeam is calculated for the simply supported(SS) boundary, the clamped-clamped(CC) boundary, the clamped-free(CF)boundary, and the clamped-simply supported(CS) boundary. The effects of geometric dimensions, length scale parameters, nonlocal parameters, piezoelectric constants, as well as the flexoelectric constants are discussed. The results demonstrate that both the flexoelectric and piezoelectric constants enhance the vibration frequency of the *** nonlocal stress decreases the natural vibration frequency, while the strain gradient increases the natural vibration frequency. The natural vibration frequency based on the NSGT can be increased or decreased, depending on the value of the nonlocal parameter to length scale parameter ratio.

关键词： piezoelectric nanobeam sandwich structure flexoelectric nonlocal strain gradient theory(NSGT)

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Passive location using CDMA mobile communication system based on repeater equipment

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The Journal of China Universities of Posts and Telecommunications 2008年第2期15卷 32-38页

作者： TIAN zeng-shan ZHOU Fei ZHANG Tian-qi Department of Communication and Information Engineering ChongqingUniversity of Posts and Telecommunications Chongqing 400065 China

To overcome the drawback of a short operation range and low-resolution of a passive location system using a civil communication signal, the new idea that utilizes code division multiple access （CDMA） signal and repeater is disposed off. First, the CDMA passive location model and observation function are given, and the error source and error range are analyzed. Subsequently, the CDMA passive location algorithm in a repeater environment is described and simulated. The simulation result shows that the algorithm can provide the location value with high accuracy.

关键词： passive location civil communication signal,location model repeater equipment operation range

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Unidirectional and stage-dependent roles of Notch1 in Wnt-responsive Lgr5+ cells during mouse inner ear development

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Frontiers of Medicine 2019年第6期13卷 705-712页

作者： Hui Jiang shan zeng Wenli Ni Yan Chen Wenyan Li ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital Fudan UniversityShanghai 200031China Key Laboratory of Hearing Medicine of NHFPC Shanghai 200031China Otorhinolaryngology Department of Jinshan Hospital Fudan UniversityShanghai 201508China

Wnt and Notch signaling play crucial roles in the determination of the prosensory domain and in the differentiation of hair cells(HCs)and supporting cells during mouse inner ear development;however,the relationship between the two signaling pathways in the mouse cochlea remains largely ***,we investigated the interactions between Notch and Wnt signaling on the basis of the bidirectional regulation of Notch1 specifically in Wnt-responsive Lgr5+progenitors during different cochlear development *** found that the downregulation of Notch1 in Lgr5+cells from embryonic day(E)14.5 to E18.5 can drive the quiescent Lgr5+cells to re-enter the cell cycle and differentiate into extra HCs,whereas the upregulation of Notch1 expression did not affect the proliferation or differentiation of otic progenitor *** effect was observed on the upregulation or downregulation of Notch1 in Lgr5+cells from E10.5 to *** concluded that the roles of Notch1 in Wnt-responsive Lgr5+cells are unidirectional and stage dependent and Notch1 serves as a negative regulator for Lgr5+progenitor activation during cochlear *** findings improved the understanding of the interactions between Notch and Wnt signaling in cochlear development.

关键词： inner ear cochlear Wnt Notch Lgr5 auditory system

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THE STEPS FORWARD OF GIS IN CHINA

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Chinese Geographical Science 2000年第1期10卷 2-7页

作者： Shu-peng Chen shan zeng Er-shun Zhong State Key Laboratory of Resource and Environmental Information Systems the Chinese Academy of Sciences Beijing P.R. China The Engineering Service Center of Resources and Environmental Information the Chinese Academy of Sciences Beijing P.R. China

Researches and applications of Geographic Information Systems (GIS) in China started in the early 1980s. In the early period, the development of GIS was mainly depended on the progress and applications of remote sensing, aerial photography, as well as computer aided design (CAD). In recent years, with the development of Global Positioning System(GPS) and Internet technology, GIS has being developed vigorously in the county. Looking ahead to the 21st century, a new era of “Digital Earth” and “Cyberspace” is coming, which will provide a great opportunity as well as a challenge to the China’s GIS circles.

关键词： progress in GIS regional difference future trends

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Design and experiment of vertical pneumatic fertilization system with spiral Geneva mechanism

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International Journal of Agricultural and Biological Engineering 2021年第4期14卷 135-144页

作者： Haibo Chen Jingfu Zheng Shaojie Lu shan zeng Silong Wei Experimental Basis and Practical Training Center South China Agricultural UniversityGuangzhou 510642China College of Engineering South China Agricultural UniversityGuangzhou 510642China

In the traditional fertilization method,a large amount of fertilizer is applied,which causes congestion *** is not conducive to the sustainable development of *** this work,a vertical pneumatic fertilization system with a spiral Geneva mechanism was designed according to the operational requirements of variable-rate and smooth *** uniformity in discharging fertilizer with different spiral angles was simulated and analyzed by extended discrete element method(EDEM)based simulation software,from where the spiral angle of the fertilizer discharge wheel was determined to be 45°.The fertilization system includes a fertilizer apparatus with a spiral Geneva mechanism,whose optimal performance parameters were obtained from the bench *** accuracy and uniformity of the fertilizer application system were taken as the evaluation *** linear relationships of the discharged amount of fertilizer with the rotational speed and the opening of the fertilizer discharging wheel were verified by both static blowing fertilization and field *** static blowing experimental results show that the discharged amount of fertilizer has a high linear correlation and accuracy with both the opening and rotational speed,and the highest correlation occurs with the rotational *** rotational speed and opening have significant effects on the discharged amount of fertilizer and the average coefficient of *** effect of the rotational speed was the most *** to the model obtained by multiple regression fittings,the optimal parameters were determined when the average coefficient of variation was small,the rotational speed was 15.9 r/min and the opening was 34.4 ***,the purpose of precise fertilization can be achieved by adjusting the opening or rotational speed in a way to get the exact amount of fertilizer discharged as required by the corresponding *** field experiment showed that the variation co

关键词： precision fertilization fertilizer apparatus variable rate technology spiral Geneva mechanism simulation analysis performance experiment

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Chemotherapy and target therapy for hepatocellular carcinoma:New advances and challenges

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World Journal of Hepatology 2015年第5期7卷 787-798页

作者： Gan-Lu Deng shan zeng Hong Shen Institute of Medical Sciences Xiangya HospitalCentral South University Department of Oncology Central South University

Primary liver cancer is one of the commonest causes of *** carcinoma(HCC) accounts for 90% of primary liver *** patients with unresectable or metastatic HCC,conventional chemotherapy is of limited or no *** is the only systemic treatment to demonstrate a statistically significant but modest overall survival benefit,leading to an era of targeted *** clinical trials of targeted drugs have been carried out with many more in *** drugs like PTK787 showed potential benefits in the treatment of *** these promising breakthroughs,patients with HCC still have a dismal ***,both a phase Ⅲ trial of everolimus and a phase Ⅱ clinical trial of trebananib failed to demonstrate effective antitumor activity in advanced *** still plays a pivotal role in advanced HCC,leading to further explorations to exert its maximum *** targeted with chemotherapy or transarterial chemoembolization is now being tested and might bring about *** targeted agents such as mammalian target of rapamycin inhibitors are under investigation,as well as further exploration of the mechanism of hepatocarcinogenesis.

关键词： Hepatocellular carcinoma Ramucirumab Regorafenib Tivantinib Molecular targeted therapy Sorafenib Linifanib Erlotinib Everolimus Sunitinib Brivanib

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Mitochondrial protective and anti-apoptotic effects of Rhodiola crenulata extract on hippocampal neurons in a rat model of Alzheimer's disease

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Neural Regeneration Research 2017年第12期12卷 2025-2034页

作者： Jun-mei Wang Ze-qiang Qu Jin-lang Wu Peter Chung Yuan-shan zeng Department of Histology and Embryology Zhongshan School of Medicine Sun Yat-sen University Guangzhou Guangdong Province China Department of Electron Microscope Zhongshan School of Medicine Sun Yat-sen University Guangzhou Guangdong Province China shanghai Ninth People's Hospital Shanghai liao Tong University School of Medicine Shanghai China Institute of Spinal Cord In)ury Sun Yat-sen University Guangzhou Guangdong Province China Co-innovation Center of Neuroregeneration Nantong University Nantong Jiangsu Province China Guangdong Province Key Laboratory of Brain Function and Disease Zhongshan School of Medicine Sun Yat-sen University Guangzhou Guangdong Province China

In our previous study, we found that the edible alcohol extract of the root of the medicinal plant Rhodiola crenulata（RCE） improved spatial cognition in a rat model of Alzheimer＇s disease. Another study from our laboratory showed that RCE enhanced neural cell proliferation in the dentate gyrus of the hippocampus and prevented damage to hippocampal neurons in a rat model of chronic stress-induced depression. However, the mechanisms underlying the neuroprotective effects of RCE are unclear. In the present study, we investigated the anti-apoptotic effect of RCE and its neuroprotective mechanism of action in a rat model of Alzheimer＇s disease established by intracerebroventricular injection of streptozotocin. The rats were pre-administered RCE at doses of 1.5, 3.0 or 6.0 g/kg for 21 days before model establishment. ATP and cytochrome c oxidase levels were significantly decreased in rats with Alzheimer＇s disease. Furthermore, neuronal injury was obvious in the hippocampus, with the presence of a large number of apoptotic neurons. In comparison, in rats given RCE pretreatment, ATP and cytochrome c oxidase levels were markedly increased, the number of apoptotic neurons was reduced, and mitochondrial injury was mitigated. The 3.0 g/kg dose of RCE had the optimal effect. These findings suggest that pretreatment with RCE prevents mitochondrial dysfunction and protects hippocampal neurons from apoptosis in rats with Alzheimer＇s disease.

关键词： nerve regeneration Alzheimer's disease intracerebroventricular injection streptozotocin neuronal apoptosis neuroprotection cytochrome c oxidase adenosine triphosphate caspase-3 NeuN neural regeneration

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Design and experimental study of the fertilizer applicator with vertical spiral fluted rollers

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International Journal of Agricultural and Biological Engineering 2023年第5期16卷 80-87页

作者： Yu Wang Yipeng Tan Silong Wei Mingming Liao Ying Zang shan zeng College of Engineering South China Agricultural UniversityGuangzhou 510642GuangdongChina Key Laboratory of Key Technology on Agricultural Machine and Equipment Ministry of EducationSouth China Agricultural UniversityGuangzhou 510642GuangdongChina Maoming Branch Guangdong Laboratory for Modern AgricultureMaoming 525000GuangdongChina

To improve the uniformity and accuracy of fertilizing amount for fertilizer applicators with spiral fluted roller,this paper experimentally studied the influence of major structural parameters on the fertilizing *** two sets of orthogonal tests,it is found that the helix angle and installation angle of spiral fluted rollers are the main factors,which affect the uniformity of fertilizer discharge and the linear relationship between fertilizing amount and opening,*** on these findings,the experiment and analysis were carried out to determine the optimal helix angle and installation angle for the spiral fluted roller The experimental results of fertilizing performance show that:when the helix angle is 45°,it able to achieve satisfactory uniformity of fertilizer discharge and linear relationship between fertilizing amount and rotational speed;when the installation angle is 40°,it enhances the accuracy of fertilizer discharge with good linear relationship between fertilizing amount and *** with the fertilizing performance of traditional fertilizer applicators with horizontally installed straight fluted roller,in the aspect of uniformity,the optimized fertilizer applicators reduce the variation coefficient of fertilizing amount within 0.2 s at low speed(10-30 r/min)from 5.1%-52.5%to 4.2%-14.7%;in the aspect of accuracy;and increase the correlation coefficient square R2 between fertilizing amount and opening from 0.93-0.97 to no less than 0.996,and the regression intercept in the fitting equation is reduced from larger than 10.0 to less than 1.0.

关键词： fertilizer applicator spiral fluted roller helix angle orthogonal test

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Development and experiment of rice hill-drop drilling machine for dry land based on proportional speed regulation

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International Journal of Agricultural and Biological Engineering 2017年第4期10卷 77-86页

作者： Fu Wei Zhang Zhiyuan Zang Ying Luo Xiwen zeng shan Wang Zaiman College of Mechanical and Electrical Engineering Shihezi UniversityShihezi 832003China College of Engineering South China Agricultural UniversityGuangzhou 510642China

Rice precision hill-drop drilling technique in dry land uses fixed hill spacing to achieve orderly planting of crops and to attain good ventilating and day-lighting effects in rice *** technique is also beneficial in improving root growth and root structure and in increasing lodging *** high-yield record of Xinjiang Production and Construction Corp’s first division for three consecutive years shows that rice precision hill-drop drilling technique in dry land is one of the important directions to developed rice cultivating mechanization *** further improve the quality of rice precision hill-drop drilling machine for dry land,a single profiling,electro-hydraulic proportional real-time adjustment of system was developed according to the agronomic *** machine can simultaneously finish various kinds of seedbed leveling,furrowing and seeding operations,as well as soil covering and ***-hydraulic proportional speed regulation makes an AMESim simulation test and analyzes the stability and error of hydraulic adjusting planting *** testing was carried out on the metering device by simultaneously employing high speed photography technology and analyzing the relationship of the high speed of hill distance and seed charge ***,machine trial was *** two-year field experiments of Xinjiang Production and Construction Corp showed that when the machine operation speed is 2.8-3.2 km/h,the sowing depth percent of pass is 75%or higher,the qualified rate of row spacing is 80%or more,the pass rate of row spacing is 90%or higher,and the quantity per hill is 75%or *** machine met the various indicators of hill sowing quality requirements.

关键词： rice hill-drop drilling for dry land quality of precision sowing proportional speed regulation field experiment

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Decellularized optic nerve functional scaffold transplant facilitates directional axon regeneration and remyelination in the injured white matter of the rat spinal cord

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Neural Regeneration Research 2021年第11期16卷 2276-2283页

作者： Yu-Rong Bai Bi-Qin Lai Wei-Tao Han Jia-Hui Sun Ge Li Ying Ding Xiang zeng Yuan-Huan Ma Yuan-shan zeng Key Laboratory for Stem Cells and Tissue Engineering Ministry of EducationSun Yat-sen UniversityGuangzhouGuangdong ProvinceChina Department of Histology and Embryology Zhongshan School of MedicineSun Yat-sen UniversityGuangzhouGuangdong ProvinceChina Co-innovation Center of Neuroregeneration Nantong UniversityNantongJiangsu ProvinceChina Institute of Spinal Cord Injury Sun Yat-sen UniversityGuangzhouGuangdong ProvinceChina Guangdong Provincial Key Laboratory of Brain Function and Disease Zhongshan School of MedicineSun Yat-sen UniversityGuangzhouGuangdong ProvinceChina

Axon regeneration and remyelination of the damaged region is the most common repair strategy for spinal cord ***,achieving good outcome remains *** previous study showed that porcine decellularized optic nerve better mimics the extracellular matrix of the embryonic porcine optic nerve and promotes the directional growth of dorsal root ganglion ***,it has not been reported whether this material promotes axonal regeneration in *** the present study,a porcine decellularized optic nerve was seeded with neurotrophin-3-overexpressing Schwann *** functional scaffold promoted the directional growth and remyelination of regenerating *** vitro,the porcine decellularized optic nerve contained many straight,longitudinal channels with a uniform distribution,and microscopic pores were present in the channel *** spatial micro topological structure and extracellular matrix were conducive to the adhesion,survival and migration of neural stem *** scaffold promoted the directional growth of dorsal root ganglion neurites,and showed strong potential for myelin ***,we transplanted the porcine decellularized optic nerve containing neurotrophin-3-overexpressing Schwann cells in a rat model of T10 spinal cord defect in *** weeks later,the regenerating axons grew straight,the myelin sheath in the injured/transplanted area recovered its structure,and simultaneously,the number of inflammatory cells and the expression of chondroitin sulfate proteoglycans were ***,these findings suggest that porcine decellularized optic nerve loaded with Schwann cells overexpressing neurotrophin-3 promotes the directional growth of regenerating spinal cord axons as well as myelin *** procedures involving animals were conducted in accordance with the ethical standards of the Institutional Animal Care and Use Committee of Sun Yat-sen University(approval ***-IACUC-2019-B034)on February 28,2019.

关键词： axonal regeneration decellularized optic nerve directional regeneration functional scaffold microenvironment neurotrophin-3 optic nerve remyelination Schwann cells tissue engineering white matter injury

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