高选择性陷波超宽带天线设计

The resonant properties of the interdigital capacitance loading loop resonator (IDCLLR) and its dual counterpart complimentary interdigital capacitance loading loop resonator (CIDCLLR) are studied. Due to the high capacitance/inductance of the IDCLLR/CIDCLLR, the resonators can generate lower resonant frequencies and narrower resonant bandwidths than many other structures. A compact ultra-wideband (UWB) antenna with quadruple sharp band-notching characteristics is presented by utilizing IDCLLRs and CIDCLLRs. Measured results show that the proposed antenna has a wide bandwidth from 3 to 11GHz(VSWR<2), with four sharp notched bands centered on 3.5, 5.2, 5.8 and 7.5GHz, respectively, avoiding the elimination of many useful frequencies. Moreover, the presence of IDCLLRs and CIDCLLRs scarcely affects the performance of the UWB antenna at its operating frequencies.     

Analysis on the gear-shifting schedule of hydraulic automatic transmission

With an advanced foreign hydraulic automatic transmission as the objective, an analytical method for the gear-shifting schedule is proposed. First the demanded maximum gradient of test is estimated. Then a test scheme and analytical procedure is formulated by initial test and hypothetical shift parameters. Finally through gear-shifting tests under different road conditions, load, accelerator pedal position limitation, throttle opening and output shaft speed are found to be the gear-shifting parameters. Under a common road condition, the gear-shifting schedule is a double-parameter schedule. Based on the driver''s demands on braking and dynamic performance, different shift schedules are made under downhill, uphill and quick releasing acceleration pedal conditions. The operation criteria of down-shift schedule on abrupt grade are proposed.     

基于温湿度变化对蒸压加气混凝土墙体变形影响试验研究

本文对加气混凝土墙体在温湿度变化下的开裂问题进行试验研究。通过调整内外墙体温度、湿度变化研究加气混凝土砌块应力应变的变化规律;利用ANSYS软件理论分析温差对墙体应力应变的影响。结果表明:随着内外墙体温差的增大,加气混凝土墙体的应变值越大;随着湿度的变化,应变值的变化不大。     

向列相液晶聚合物接枝碳纳米管制备及其性能

为了制备碳纳米管/液晶复合材料,合成了液晶单体1,4-苯二甲酸二-(4-羧基苯)酯,采用原位聚合法将其与1,6-己二酸、1,4-联苯酚、碳纳米管进行共聚,制备了不同配比的碳纳米管/液晶复合材料.利用红外光谱(FT-IR),差式扫描量热仪(DSC)、偏光显微镜(POM)、扫描电子显微镜(SEM)等研究了碳纳米管在液晶基体中的分散以及复合材料的液晶性.结果表明,少量的碳纳米管可以在液晶中分散良好;液晶复合材料的液晶区间变窄,但没有改变液晶复合材料的液晶类型.     

单因素时间序列ARMA建模在卡钻预测中的应用研究

为了在实际钻井过程中避免和减少卡钻事故的发生,提出一种以单因素时间序列ARMA建模为基础,对钻井卡钻事故做出预期判断的方法,并利用钻井实际中的数据验证此方法的可行性。运用Eviews软件对青海地区某地热勘探井的相关数据建立各个参数的时序模型,对未来钻井数据进行预测,同时对各个ARMA模型做功率谱估计,比较相邻2个ARMA模型的功率谱密度,计算各个参数的综合功率谱叠加偏差值,作为判断卡钻的依据。实践证明此方法可提前预测钻井过程中的卡钻事故。     

Safety threshold of high-speed railway pier settlement based on train-track-bridge dynamic interaction

This paper presents a method to determine the safety threshold of bridge pier settlement in high-speed railways.An analytical expression of the mapping relationship between the pier settlement and the rail deformation is derived theoretically for the double block ballastless track-bridge system.By adopting the superposition of the track random irregularity and the rail deformation caused by the pier settlement as the excitation inputs,the variations of vehicle dynamics indices with pier settlement are comparatively analyzed.Then,the safety threshold of the bridge pier settlement is obtained according to the limit of vehicle running safety and ride comfort indices of the high-speed trains.Results show that the dynamics indices of different trains have different sensitivities to the pier settlement,and the train CRH2C is the most sensitive one among all the types of Chinese high-speed trains.When passing through the bridges in common span with pier settlement at the speed of 250–350 km/h,the trains suffer the low-frequency excitations,and the vertical acceleration of car body is most sensitive to the pier settlement of all the dynamics indices.When the car body vertical acceleration just exceeds the allowable limit,the critical settlement value is 23.4 mm,which is much bigger than the pier differential settlement limit in the current code for Chinese high-speed railways.     

废液晶显示器铟的资源化回收研究进展

液晶显示器(liquid crystal display,LCD)的回收处理是资源与环境领域的重要问题。介绍了LCD的组成成分并阐述了其对环境的潜在风险,综述了近年来国内外对废LCD中铟的资源化回收处理技术的研究现状,指出了目前该研究领域中存在的问题及后续的研究方向。     

我国海域资源产权制度解析

海域资源产权最基本的权能为海域所有权和海域使用权。早期,我国海域资源产权制度是所有权和使用权不分,产权不清,导致早期海域使用出现＂无序、无度、无偿＂。随着人们对海洋价值认识的进一步深化,海洋开发不断增强,国家逐步开展海域行政许可和有偿使用制度,海域所有权和海域使用权实行分离机制,海域所有权和海域使用权的关系得以理顺,海域资源产权分离机制是我国海域管理工作的重大进步。在海域管理实践中,需要不断巩固和完善这种机制,以促进海域资源的保值和增值。     

建筑业发展对新型墙体材料发展的影响

本文概括了我国与墙体材料有关的城镇化建设、住宅产业化、绿色建筑、高层建筑的发展,分析了建筑业的发展对墙体材料的要求,进而论述了新型墙体材料的发展趋势。     

基于RTDS的高压直流输电控制功能研究

为了对高压直流输电系统实时仿真并对控制功能进行研究,基于实时仿真平台RTDS搭建了高压直流输电控制保护详细仿真模型,通过进行启停控制、阶跃响应、功率控制、无功控制、交流系统故障等试验,研究了直流输电基本控制功能,验证了模型的准确性和有效性,控制系统能准确和快速响应,表明了该模型可用于直流运行特性和交直流交互影响研究。