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AnALYSIS OF THE SCATTERIng OF RIvET On AIRCRAFT

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Journal of Electronics(China) 2002年第4期19卷 434-437页

作者： Guo Jingli Ji Yicai Liu Qizhong (institute of Antenna & em Scattering, Xidian University, Xi’an 710071) Institute of Antenna & em Scattering Xidian University Xi'an 710071

This letter investigates the scattering characteristic of the rivets on aircraft. The Electric Field Integral Equation (EFIE) is used with the moment method to calculate the current distribution on the surface of the rivet. With the application of Gaussian integral corresponding triangular cell, the time to fill the Z matrix is greatly reduced. Finally, the RCS of a type of rivet on aircraft is analyzed.

关键词：瞬时法雷达截面飞机铆钉电力

AnALYSIS OF MOnOPOLE AnTEnnA On CIRCULAR DISC BY MODE MATCHIng

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Journal of Electronics(China) 2001年第2期18卷 185-187页

作者： Sun Baohua Zhang Pushun Liu Qizhong (Institute of Antennas and em Scattering, Xidian University, Xi’an 710071) Institute of Antennas and em Scattering Xidian UniversityXi'an 710071

Mode matching is used for the analysis of monopole antenna on circular disc, which is achieved by developing a novel model consisting of two artificial ground planes above and bellow the monopole antenna. Using this model, the input impedance is computed and compared with measured data reported in literatures, and excellent agreement is observed.

关键词： Monopole antenna Mode matching Circular disc

Effects of human umbilical cord serum on proliferation and insulin content of human fetal islet-like cell clusters

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Hepatobiliary & Pancreatic Diseases International 2004年第1期3卷 144-148页

作者： Dong Xia, Hong-Yuan He, Zheng-Ming Lei, Pei-Ming Zhang and Yong Guo Luzhou, China Department of General Surgery, West China Hospital , and Department of Surgery, Fifth Hospital of Sichuan Province , Chengdu 610041, China Department of Histology and em- bryology , and Hepatobiliary and Pancreatic Laboratory , Luzhou Medical College, Luzhou 646000, China Department of General Surgery West China Hospital Chengdu 610041 China. juliahhy@***

BACKGROUnD: Type 1 diabets is an autoimmune disease caused by the destruction of pancreatic β-cell with an in- creased incidence worldwide in the closing decades of the 20th century. This study was to investigate the effects of human umbilical cord serum (UCS) on the proliferation and function of human fetal islet-like cell clusters (ICCs) in vitro. METHODS: Eight fresh pancreatic glands obtained after in- duction of labor with water bag were mildly exposed to col- lagenase v, and the digested cells were cultured in a RPMI- 1640 medium plus 10% pooled UCS or fetal calf serum (FCS) to permit cells attachment and outgrowth of ICCs. RESULTS: In 8 consecutively explanted glands, develop- ment and proliferation of ICCs were observed. In the pre- sence of FCS, the outgrowth of ICC took place on the top of a flbroblast monocellular layer. UCS affected less growth of fibroblasts and increased the formation of ICCs about four-fold compared with explants from the same glands maintained in FCS. In both UCS and FCS, the insulin con- tent of the medium was variable to a certain extent and progressively declined from day 2 to day 6. Dithizone- stained ICCs in UCS suggested that most cell clusters were islet cells ( β-cells), and the purity of islets was estimated 80%-90%. The ultrastructure of the cultured cells showed a large number of granule-containing cells, most of which were identified as β-cells. COnCLUSIOn: We conclude that in comparison with ex- plants with FCS, the yield of ICCs and purification of islet cells are markedly increased by UCS and may facilitate the proliferation of pancreatic β-cells intended for islet trans- plantation.

关键词： islet cell culture islet-like cells clusters umbilical cord serum fetal calf serum

nest site selection and reproductive parameters of the threatened Atlantic Royal Flycatcher(Onychorhynchus swainsoni)and their significance for conservation

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Avian Research 2021年第1期12卷 63-75页

作者： Daniel F.Perrella Paulo v.Q.Zima Mercival R.Francisco Programa de Pós-Graduacao em Ecologia e Recursos naturais Universidade Federal de SaCarlosWashington Luiz km 235SaCarlos 13565-905Brazil Departamento de Ciências Ambientais Universidade Federal de SaCarlosRod.Joao Leme dos Santos km 110Sorocaba 18052-780Brazil

Background:Patterns of rarity can be explained by reproductive rates,levels of endemism,and habitat specificity,and knowledge on these parameters is important to understand the levels of vulnerability of each species and to formulate conservation ***,we studied nest-site selection and breeding biology of the Atlantic Royal Flycatcher(Onychorhynchus swainsoni),a poorly known vulnerable bird endemic to the Brazilian Atlantic ***:We addressed nest site selection in three different levels:first,we searched for nests near and far from water to investigate whether birds could select water proximities to construct nests;second,we examined if they could select certain streams in detriment of others,and we analyzed the characteristics of used and non-used streams,and third,in streams in which nests were found,we addressed nest site selectivity by comparing a number of parameters between nest sites and random ***,we provide information on breeding biology parameters related to annual ***:During five breeding seasons,we found 23 nests in a well-preserved forest *** of the nests were constructed above water,and they were found in streams that were about 4 m in width,instead of smaller streams with about 1.5 m in *** analyses revealed that within the used streams,nests were constructed in sites with lower vegetation density in relation to random points,while stream width,water speed,and canopy cover presented no significant *** Royal Flycatchers in our study had a 22-day incubation period and 24 to 27-day nestling *** nest survival was comparatively high(62%),but clutch size was small(n=2 eggs)and Along the nesting streams,we found an average of 1.62±0.07 breeding pairs/***:These data suggest that nesting habitat specificity and low annual fecundity are among the factors contributing to the rarity of the Atlantic Royal Flycatcher in large forest continuums and to its absenc

关键词： Atlantic Forest Birds Breeding biology Daily survival rate Endangered species Specialized bird species

Awareness of Patients toward Dental Implants as an Alternative Treatment to Replace Missing Teeth in Kinshasa, D. R. Congo

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Open Journal of Stomatology 2018年第12期8卷 345-353页

作者： em Kalala-Kazadi Patrick Disidi-Yakini Fidèle nyimi-Bushaba Edize Ekofo-Ingaya Augustin Mantshumba-Milolo Unit of Periodontology Department of Dental Medicine Faculty of Medicine University of Kinshasa Kinshasa Congo Oral and Maxillo-Facial Surgery University of Kinshasa and Kinshasa Congo Wuhan University Wuhan China Prosthesis and Orthodontic Service Department of Dental Medicine Faculty of Medicine University of Kinshasa Kinshasa Congo

Background: Dental implant is an artificial root inserted in the jawbone, which restores a lost tooth so that it looks, feels, and is fit like a natural tooth. It is considered to be the best treatment option for single or multiple missing teeth. The aim of this study was to assess the awareness of patients about dental implants as an alternative treatment in Congolese patients. Materials and Methods: A cross-sectional study was conducted in two institutions namely, CBCO Bandal and ngaliema Clinic, from August to December 2017. A total of 450 respondents have participated in the survey. A printed questionnaire comprised of 20 questions in order to evaluate patients dental awareness was used. Gender, level of education, awareness of dental implant and dental implants therapy, sources of information and the expectation about the sources of information were assessed. The collected data were entered in Microsoft Excel 2010 and analyzed by SPSS (IBM SPSS 20.0, Chicago, IL, USA) software. Results: Out of 450 participants, 14.4% were aware of dental implants. The main disadvantage of dental implant was the high cost. When asked about the anchorage, 86% didn’t know where the dental implant was anchored. ninety-two percent didn’t know for how long an implant last, 6% thought that dental implant last for a lifetime. When patients were asked about the sources of information, the dentist (5%) and media (5.5%) were the main sources of information. The majority of patients (88.4%) would like to get information about dental implants from their dentist. Conclusion: Dentists should be more involved in the promotion of information about dental implants as a treatment modality to replace missing teeth.

关键词： Awareness Dental Implant Treatment Modality Oral Rehabilitation

Simulation of electromagnetic high-frequency wave propagation processes in multilayer geo-structures

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Geohazard Mechanics 2023年第3期1卷 203-207页

作者： A.P.Khmelinin A.I.Konurin E.v.Denisova Chinakal Institute of Mining Siberian BranchRussian Academy of Sciences54 Krasny ProspectNovosibirsk630091Russia

The paper describes the research findings on georadar detection of hydraulic fractures in hydrocarbon *** and physical modeling enables studying effect exerted by the electromagnetic properties of the created fracture fill and by the properties of the enclosing formation on the coefficient of high-frequency em wave reflection from the interface.

关键词： Electromagnetic properties Reflection coefficient Plane electromagnetic wave Hydraulic fracture Georadar Radarogram

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柬埔寨与中国贸易规模与结构研究

柬埔寨与中国贸易规模与结构研究

作者：宋文杰（em AROn）西北师范大学

学位级别：硕士

柬中自1996年签订相关领域合作协议以来,双边贸易高速增长,2015年双边贸易规模达到44亿元,柬中互为重要贸易伙伴,合作领域不断深化。当前,柬中两国新一届领导人登上历史舞台,两国贸易关系在取得新突破的同时受到国际市场的影响日益深刻... 详细信息

柬中自1996年签订相关领域合作协议以来,双边贸易高速增长,2015年双边贸易规模达到44亿元,柬中互为重要贸易伙伴,合作领域不断深化。当前,柬中两国新一届领导人登上历史舞台,两国贸易关系在取得新突破的同时受到国际市场的影响日益深刻,柬中贸易失衡及结构不优问题给柬中贸易发展带来巨大挑战,研究柬中贸易关系,对于优化柬中贸易结构,实现柬中贸易互补,促进两国产业结构转型升级,促进柬中贸易深入合作意义重大。本文着眼于柬中贸易规模与结构的研究。首先,应用文献综述法对柬中贸易规模与结构的背景、研究现状、相关理论等进行综述;其次,结合相关理论,通过定性分析和定量分析相结合的方法,从柬中两国贸易的规模、结构、互补性、依存度等方面进行分析,找出其存在的问题和原因;然后,根据两国实际情况,提出优化柬中贸易结构建议,包括增进互信,营造环境、发挥优势,优化结构、开放合作,共赢发展、开拓机遇,应对挑战;最后,对全文进行总结和展望。研究发现贸易失衡、进口中国商品依存度高、出口中国商品技术含量低是柬中贸易的主要特点,文章认为国际环境、经济发展水平、资源禀赋差异与贸易政策是柬中贸易失衡与结构不优的主要原因,这符合两国当前的发展阶段,最后文章从政治互信、贸易政策、开放合作、互促互补等角度给出优化柬中贸易结构的建议,并指出柬中贸易逆差将存在于相当长一段时期,但有利于两国政治经济发展。

关键词：贸易规模柬埔寨贸易结构结合度劳伦斯指数