微波遥感的发展与应用

微波遥感作为遥感技术的一个分支,是20世纪70年代发展起来的一门年轻的学科.着重以我国微波遥感发展的历程为例,回顾了三十多年来微波遥感领域学术与技术的迅速发展,比较分析了微波遥感对于可见光和红外遥感有着不可比拟的优越性,因而在海洋、冰雪、大气、测绘、农业、灾害监测等方面都有着广泛的应用.同时提出了目前我国在微波遥感领域存在的若干不足并指出了今后的研究方向.     

Undrained dynamical behavior of Nanjing flake-shaped fine sand under cyclic loading

A series of dynamic behavior tests on Nanjing flake-shaped fine sand were performed by using the WFI cyclic triaxial apparatus made in England. The dynamic behaviors of Nanjing flake-shaped fine sand under different static deviator stress levels and cyclic stress ratios were studied. Through comparing the effective stress path under cyclic loading with static loading, the processes of liquefaction of saturated Nanjing flake-shaped fine sand with development of dynamic pore-water pressure, including the initial compact state, compression state and dilative state, were investigated. The variation of the shear stiffness with the number of cycles and cyclic strain was investigated by analyzing the secant shear modulus in each unload-reload loop of dynamic stress-strain relationship. And by means of the exponential function, the empirical equations of the relationship between secant shear modulus Gsec, shear modulus ratio Gsec/Gmax and cyclic strain ε were established based on series of test results. The results show that according to different combinations of static deviator stress and cyclic stress, two kinds of failure patterns with deviator stress reversal or no deviator stress reversal are observed in the samples tested in this series, including cyclic mobility and the failure of accumulation residual strain. In addition, the degradation of dynamic shear modulus is due to the development of vibration pore-water pressure and it is observed that the shear modulus reduces with the progressive number of cycles.     

Sand deposit-detecting method and its application in model test of sand flow

Against the background of the sand-flow foundation treatment engineering of Guangzhou Zhoutouzui variable cross-section immersed tunnel, a kind of sand deposit-detecting method was devised on the basis of full-scale model test of sand-flow method. The real-time data of sand-deposit height and radius were obtained by the self-developed sand-deposit detectors. The test results show that the detecting method is simple and has high precision. In the use of sand-flow method, the sand-carrying capability of fluid is limited, and sand particles are all transported to the sand-deposit periphery through crater, gap and chutes after the sand deposit formed. The diffusion range of the particles outside the sand-deposit does not exceed 2.0 m. Severe sorting of sand particles is not observed because of the unique oblique-layered depositing process. The temporal and spatial distributions of gap and chutes directly affect the sand-deposit expansion, and the expansion trend of the average sand-deposit radius accords with quadratic time-history curve.     

Field study of plastic tube cast-in-place concrete pile

The compositions, technical principles and construction equipments of a new piling method used for ground improvement plastic tube cast-in-place concrete pile were introduced. The results from static load tests on single piles with different forms of pile shoes and on their composite foundations were analyzed. The distribution patterns of axial force, shaft friction and toe resistance were studied based on the measurements taken from buried strain gauges. From the point of engineering application, the pile has merits in convenient quality control, high bearing capacity and reliable quality, showing higher reasonability, advancement and suitability than other ground improvement methods. The pile can be adopted properly to take place of ordinary ground improvement method, achieving greater economical and social benefits.     

予岂好辩哉?予不得已也——《孟子》一书对孟子辩者形象的塑造

长于论辩,是《孟子》散文的突出特征.《孟子》一书通过对孟子言行的记录,不仅表现了孟子的思想和理论,亦成功地为后人展示了一个鲜活的辩者形象.孟子与时人的论辩涉及政治、经济、伦理道德、哲学等诸多领域;通过对旁征博引、因势利导、诱敌入彀、归谬反驳、执经行权等论辩方法的娴熟驾驭,表现出鲜明的个性特点.     

爱的阶梯——析克里斯蒂娜·罗塞蒂诗歌主题变换

克里斯蒂娜一生孤独迷离,她弃绝人间的舒适享乐全心追求永恒的精神快乐.诗歌是她生活的真实写照:从初恋失败,父亲病逝,到中年全方位的社交活动,再到孤独的晚年隐退.她的诗歌也呈现出统一协调的三部曲:从温婉细腻的抒情诗,到内涵丰富的叙事诗,再到热烈苍凉的祈祷文.爱是诗人背后最隐秘的缘由.为寻求心灵的平静,她试图在爱中找到永恒,却一次次被爱推着向前走:从人世爱恋到社会爱心,再回归上帝.     

Influencing factors of compressive strength of solidified inshore saline soil using SH lime-ash

Through unconfined compressive strength test,influencing factors on compressive strength of solidified inshore saline soil with SH lime-ash,ratio of lime-ash(1-K),quantity of lime-ash,age,degree of compression and salt content were studied.The results show that because inshore saline soil has special engineering characteristic,more influencing factors must be considered compared with ordinary soil for the perfect effect of solidifying.     

一种风幕式抽油烟机的实验研究

通过对厨房油烟扩散机理的分析和模型实验,研究了影响油烟控制的各种因素,采用实验与计算流体力学仿真技术相结合的方法,对不同情况下油烟罩的油烟控制性能进行了比较、分析,设计出了一种新型节能型抽油烟机。     

Creep testing and viscous behavior research on carbon constructional quality steel under high temperature

Creep tests under at a certain temperature and different stress levels were performed on two carbon constructional quality steels at a certain stress level and different temperatures,and their creep curves at high temperature were obtained based on analyzing the testing data.Taking 45 steel at a certain temperature and stress as the example,the integral creep constitutive equation and the differential stress-strain constitutive relationship were established based on the relevant rheological model,and the integral core function was also obtained.Simultaneously,the viscous coefficients denoting the viscous behavior in visco-plastic constitutive equation were determined by taking use of the creep testing data.Then the viscous coefficients of three carbon steels(20 steel,35 steel and 45 steel) were compared and analyzed.The results show that the viscosity is different due to different materials at the same temperature and stress.     

Optimization of rheological parameter for micro-bubble drilling fluids by multiple regression experimental design

In order to optimize plastic viscosity of 18 mPa·s circulating micro-bubble drilling fluid formula,orthogonal and uniform experimental design methods were applied,and the plastic viscosities of 36 and 24 groups of agent were tested,respectively.It is found that these two experimental design methods show drawbacks,that is,the amount of agent is difficult to determine,and the results are not fully optimized.Therefore,multiple regression experimental method was used to design experimental formula.By randomly selecting arbitrary agent with the amount within the recommended range,17 groups of drilling fluid formula were designed,and the plastic viscosity of each experiment formula was measured.Set plastic viscosity as the objective function,through multiple regressions,then quadratic regression model is obtained,whose correlation coefficient meets the requirement.Set target values of plastic viscosity to be 18,20 and 22 mPa·s,respectively,with the trial method,5 drilling fluid formulas are obtained with accuracy of 0.000 3,0.000 1 and 0.000 3.Arbitrarily select target value of each of the two groups under the formula for experimental verification of drilling fluid,then the measurement errors between theoretical and tested plastic viscosity are less than 5%,confirming that regression model can be applied to optimizing the circulating of plastic-foam drilling fluid viscosity.In accordance with the precision of different formulations of drilling fluid for other constraints,the methods result in the optimization of the circulating micro-bubble drilling fluid parameters.     

Adaptive Modeling for Security Infrastructure Fault Response

Based on the analysis of inherent limitations in existing security response decision-making systems,a dynamic adaptive model of fault response is presented.Several security fault levels were founded,which comprise the basic level,equipment level and mechanism level.Fault damage cost is calculated using the analytic hierarchy process.Meanwhile,the model evaluates the impact of different responses upon fault repair and normal operation.Response operation cost and response negative cost are introduced through quantitative calculation.This model adopts a comprehensive response decision of security fault in three principles-the maximum and minimum principle,timeliness principle,acquiescence principle,which assure optimal response countermeasure is selected for different situations.Experimental results show that the proposed model has good self-adaptation ability,timeliness and cost-sensitiveness.     

采用数据流图的故障模型生成算法及其应用

为有效地解决系统级故障注入试验建模困难问题,提出语言级生成数据流图,并以此构造动态故障树的故障模型建立方法.通过对故障过程数据流分析,找出数据依赖关系并构造了故障模型生成算法.与其他方法比较,本算法具有动态性,提高了故障覆盖率,减少了系统开销,使故障注入试验更易实现.     

基于故障树的火电厂脱硝系统故障分析方法

脱硝系统在火电厂运行过程中扮演着重要角色, 系统的正常运行以及故障预防措施的制定对火电厂正常工作具有重要意义。提出了一种基于故障树的火电厂脱硝系统故障分析方法。通过分析脱硝系统的工作原理确定全 部故障事件, 并根据故障事件之间的逻辑关系建立脱硝系统故障树, 通过定性和定量分析确定系统的薄弱环节, 对火电厂脱硝系统的各种故障制定应对方案, 为企业安全生产提供指导意见。     

一种代价估算规则在入侵响应系统中的应用

代价估算问题是入侵响应中成本分析的重要依据,因此也是影响入侵响应系统是否做出响应决策的关键问题.作者在分析了现有Northcutt的损失代价估算方法并对其代价估算规则进行了总结的基础上,提出了一种新的代价估算准则,并将基于该代价准则的成本分析模块应用到入侵响应系统中设计了基于成本分析的入侵响应系统,进而对该响应系统进行了损失代价估算、响应代价的估算,结果表明该项应用能够合理有效的利用有限的系统资源.     

多传感器的关节故障检测及容错策略

为提高空间机器人关节驱动系统的可靠性,研制具有多种传感器的模块化关节,提出基于多传感器的关节故障检测算法及关节的容错策略,并根据关节运动速度大小建立阈值自动调整策略.试验结果表明,采用该算法,克服了基于模型关节故障检测策略对模型的依赖,并保证关节在低速和高速范围内,均可快速地检测关节出现的故障,保证关节安全稳定运行.     

交换机故障分析与维护处理探讨

为保障通信网络的畅通和交换机安全、稳定的运行,在交换机出现故障后应当迅速地作出分析处理,找出故障原因和故障点,对故障进行排除,但要能快速、准确的对故障进行分析定位,就必须了解交换机发生的故障类型以及较高的故障分析和维护处理水平。     

模拟集成电路故障诊断与参数辨识的代数方法

为实现模拟电路参数辨识和降低故障诊断成本,提出一种基于矩阵扰动理论的模拟电路故障诊断和参数辨识方法。该方法不同于基于数字信号处理（DSP）与人工智能的方法,而是从代数观点出发,以被测电路响应矩阵的本征值随被诊断器件参数的变化而变化的对应关系为基础,建立故障模型。该模型将故障检测,故障定位和参数辨识一体化处理,具有易于工程实施的优点。实验结果表明该方法的计算时间开销小,可降低测试成本,故障定位和故障参数辨识精度高,实验结果中的最大辨识误差为2.35%。     

边际成本法在电力系统功率交换费用计算中的研究

提出采用改进的边际成本法结合电力系统ＡＣ潮流,在综合考虑电网运行安全可靠性和经济性的基础上,分别对电力系统节点间和网络间功率交换费用比率进行了理论分析和模拟计算。本文所研究的问题是对功率问题量化的探讨,它是今后在我国电力市场运作中必然要面临的问题。本文以２００５年东北电网规划５００ｋＶ电压等级的超高压电网为计算实例,对不同运行方案的计算结果进行了分析和比较,在以省为实体的方针指导下,利用边界潮流法     

基于接地故障类型的综合选线研究

根据大量的实际和模拟实验的故障录波数据,分析了影响小电流接地系统单相接地故障选线可靠性的原因。对接地故障的类型进行了分类,建立了基于接地故障类型判别的小电流接地选线方法,并经现场运行证明了选线的准确性和可靠性。     

故障诊断效率与评估

本文讨论电子设备故障检测序列组合对故障诊断效率的影响．按检测开销和故障发生概率，适当安排检测顺序，组成二叉和多叉故障分离树，可以提高检查效率，缩短检查次数，压缩检查时间，计算显示，良好检测顺序可节省开销1／3．文章还分析了每次故障诊断结果是确诊或误诊的随机现象评判诊断系统的诊断准确率是抽样检验问题．引入假设检验方法，设置显著水平和提出假设，对设备故障诊断系统的准确率进行评判减少了误判概率．文章对建造和评估设备故障诊断系统有参考价值．