28 research outputs found

    导线张力对输电杆塔安全性和经济性的影响研究

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    针对使用广泛的500 kV架空输电线路,分别研究了在轻、中、重冰区,由断线及不均匀覆冰引起的导线张力对输电杆塔安全性和经济性的影响。研究表明:导线张力增加0~20%,若保持杆塔杆件规格不变,悬垂塔的超限杆件比例为0~51%,耐张塔的超限杆件比例为0~4%;若增大杆塔杆件规格以保证安全,悬垂塔的塔重增加0~28%,耐张塔的塔重增加0~5%;覆冰越厚,由断线引起的导线张力对杆塔影响越小,由不均匀覆冰引起的导线张力对杆塔影响越大;导线张力主要影响悬垂塔横担上、下平面交叉材、塔身主斜材等杆塔杆件。因此,对重要输电线路和输电线路重要区段,推荐重点加强悬垂塔的防串倒及抗冰能力。研究结论对工程实践具有一定的指导意义

    Well Width Dependence of Band Gap Renormalization of Single ZnO/MgZnO Quantum Well

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    通过室温下的时间积分光致发光(Pl)谱,研究了阱宽lW渐变的znO/Mg0.1zn0.9O单量子阱在高激发强度下的能带重正化与阱宽的关系。实验中光生载流子浓度为n=1.6x1014CM-2,在lW从2.3 nM渐变到4.3 nM,Pl谱峰位的红移量从5.9 MEV变化到97.1 MEV。红移量随阱宽增大而增加,但增加率却逐渐减少。当lW>2αb(αb,znO体材料激子玻尔半径,约为2 nM)时,红移量逐渐呈现出饱和的趋势(100 MEV)。研究发现峰位的红移是由于多体效应所导致的能隙收缩以及在高的激发强度下带内填充效应的这两种机理相互竞争的结果。Band gap renormalization of ZnO/Mg0.1Zn0.9O single quantum well(QW) with gradual well width(Lw) is studied by room-temperature time integrated photoluminescence(PL) spectra at high excitation power density.The photo-generated carrier density is n=1.6×1014 cm-2 and the magnitude of red shift of PL spectrum peak increases from 5.9 meV to 97.1 meV with Lw changing from 2.3 nm to 4.3 nm.With Lw increaseing,the red shift increases but the increase rate gradually decreases.When Lw>2αB(αB,the exciton Bohr radius of ZnO bulk,is about 2 nm),the red shift starts to be gradually saturated.It is found that the red shift is the competition result of energy gap contraction due to many body effect and intraband filling effect at high excitation power density.The result is useful for designing and application of ZnO QW-based optoelectronic devices.国家973计划(2004CB719804);国家自然科学基金(60876007);广州市科技局推荐项目(2005Z3-C7451)资助课

    Analysis on epidemiological charateristics of chlamydia trachomatis infection in Jiangsu Province,2006-2011

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    目的了解江苏省2006-2011年生殖道沙眼衣原体感染的流行病学特征,为制定防治生殖道沙眼衣原体感染的策略提供科学依据。方法收集2006-2011年江苏省通过中国疾病预防控制信息系统报告的生殖道沙眼衣原体感染病例资料,并对资料进行流行病学分析。结果 2006-2011年,江苏省生殖道沙眼衣原体感染发病率呈快速上升的趋势,2006年为0.12/10万,2011年为3.15/10万,发病率年均增长速度为92.23%;在报告的5 859例病例中,男女性别比为0.3∶1,各年生殖道沙眼衣原体感染男女性别差异有统计学意义;发病年龄主要集中在20~29岁年龄组,占50.96%;江苏省生殖道沙眼衣原体感染报告病例主要集中在苏南和苏中的较发达城市;主要以家庭及待业者和工人为主。结论江苏省生殖道沙眼衣原体感染发病率快速增长,应加强对生殖道沙眼衣原体的防治,以控制其感染的快速流行。江苏省医学重点人才(RC2011086);江苏省医学重点人才(RC2011087); 江苏省科技项目(Y201029

    A Journey into the City. Migrant Workers' Relation with the Urban Space and Struggle for Existence in Xu Zechen's Early Jingpiao Fiction

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    In contemporary China, rural-urban migrants constitute a new urban subject with entirely new identity-related issues. This study aims at demonstrating how literature can be a valid field in investigating such evolving subjectivities, through an analysis of Xu Zechen’s early novellas depicting migrants’ vicissitudes in Beijing. Combining a close reading of the texts and a review of the main social problems characterising rural-urban migration in China, this paper focuses on the representation of the identity crisis within the migrant self in Xu’s stories, taking into account the network of meanings employed by the writer to signify the objective and subjective tension between the city and the countryside

    A Simple and Reliable Control Method for Preventing Surge of High Pressure Centrifugal Air-blower

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    通过有色冶金行业首次使用的d200-0.28/0.97高压离心鼓风机的配置设计,现场安装、调试和生产使用所积累的经验,详细地分析了高压离心鼓风机发生喘振的原因及防止喘振的控制原理,并介绍一种简单、可靠的防喘振控制措施;计算出了该机的防喘振控制点,提出了防喘振控制的操作要求.经过近七年的实践,证明该防喘振控制措施确实简单、可靠、安全、实用A detailed study of surge factors and the method of controlling prevention of surge in the type of D200 0.28/0.97 high pressure centrifugal airblower used in nonferrous metal industries is reported.A simple and reliable surge prevention control method is proposed. The preventing surge control point is calculated in this airblower and the operation specification of controlling surge prevention is put forward.It can be proven by practice for 7 years that this method for controlling surge prevention is simple, reliable, safe

    脱氢枞胺分子印迹聚合物的吸附性能研究

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    以脱氢枞胺为模板分子,丙烯酸为功能单体,马来松香乙二醇丙烯酸酯为交联剂,合成了脱氢枞胺分子印迹聚合物,对聚合物的结构和性能进行了表征,对分离提纯脱氢枞胺的性能进行了测定。结果表明,聚合反应的最佳条件为:0.285 g脱氢枞胺(1 mmol)、0.288 g丙烯酸(4 mmol)和4.91 g马来松香乙二醇丙烯酸酯(8 mmol);反应溶剂为氯仿(30 mL),汽油(15 mL),水(300 mL)混合溶剂;引发剂为偶氮二异丁腈(0.27 g);反应时间5 h,反应温度为70~80℃,搅拌速度为300 r/m in。最佳静态吸附条件为:以体积分数为80%的乙醇为溶剂配制脱氢枞胺溶液,质量浓度为2 g/L,分子印迹聚合物为20~40目,吸附温度70℃,振荡速度150 r/m in。脱氢枞胺分子印迹聚合物对脱氢枞胺的静态平衡吸附时间为12 h,吸附量为223 mg/g,平衡解吸时间为12 h,解吸率为95.9%。经分子印迹聚合物分离纯化后的脱氢枞胺质量分数由67.4%提高到98.3%。说明该分子印迹聚合物对脱氢枞胺的特异吸附性能良好,可以达到分离纯化脱氢枞胺的目的

    转录因子调控植物萜类化合物生物合成研究进展

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    萜类化合物是植物次生代谢物中结构和数量最多的一类化合物,它们在植物体内以及植物与环境和其它生命体的相互作用中发挥重要作用。转录因子通过调控代谢通路中基因的转录起始来调节次生代谢物质的产量。目前,研究发现参与萜类合成的转录因子家族主要有6个,包括AP2/ERF、b HLH、MYB、NAC、WRKY和bZIP。该文主要对其家族的结构特点、调控模式以及研究进展进行综述,以期进一步丰富萜烯合成的网络调控,为植物萜类相关的分子育种、优质栽培和病虫害生物防治等提供新的思路与方法
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