丹江口工程大坝加高后的几个水力学问题

依托1∶100水工模型试验成果,重点介绍了丹江口大坝加高后的几个水力学问题如泄流能力、坝面压力特性、河床局部冲刷、下游河道流速流态、泄洪对电厂及航运的影响等.研究显示:大坝加高后泄流能力可满足设计要求,坝下河床冲刷加重,挑距加远,设计洪水22 300 m3/s时坝下冲坑最低点高程为43.0 m,各级泄量冲坑上游坡均缓于临界坡,也略缓于初期工程同级流量冲坑的上游坡;坝下600 m以内为护岸工程重点防护段,岸边流速为5.8～9.8 m/s;泄洪对丹江口电厂影响较小,对自备电站不利影响较为显著;最大通航流量6 200 m3/s时下游引航道口门区流态复杂,水流较混乱.     

鄱阳湖水质状况分析与评价

鄱阳湖是我国最大的淡水湖,其水质现状为人们普遍关心的问题。通过对1980年1月至1988年12月水质资料的搜集整理,对鄱阳湖水质的时空分布规律进行分析。作出的结论是:鄱阳湖虽已受到污染,但其水质总体情况尚属良好,在全国淡水湖泊中属最好的湖泊之一,应予特别珍惜、保护。     

Generalizations of Ho–Lee’s binomial interest rate model I: from one- to multi-factor

In this paper a multi-factor generalization of Ho–Lee model is proposed. In sharp contrast to the classical Ho–Lee, this generalization allows for those movements other than parallel shifts, while it still is described by a recombining tree, and is a process with stationary independent increments to be compatible with principal component analysis. Based on the model, generalizations of duration-based hedging are proposed. A continuous-time limit of the model is also discussed. This research was supported by Open Research Center Project for Private Universities: matching fund subsidy from MEXT, 2004–2008 and also by Grants-in-Aids for Scientific Research (No. 18540146) from the Japan Society for Promotion of Sciences.     

西气东输工程用感应加热弯管技术条件探讨

在对国外X70管线弯管技术条件进行调查分析与研究的基础上，对其中的几个关键技术问题包括母管成分，弯管的制造工艺和技术路线，强度与韧性要求，屈强比，Cu污染问题等进行了讨论。一些观点在西气东输感应加弯管技术条件中得到应用。     

黄河内蒙古河段典型凌情过程模拟

近十几年受人类活动和气候变化等影响,黄河内蒙古河段冰情出现新的特征,突发凌情频繁出现,原有的内蒙古河段冰模拟方法已不能满足当前凌情防治的需要,亟待建立能反映凌情物理特性变化规律的河段冰情动态发展数学模型。在实测资料基础上,研究了黄河内蒙古河段冰情时空变化规律,以及河道资料不完整、支流流量资料缺乏及冰桥位置的确定等问题。应用一维冰情数学模型模拟2012—2013年凌汛期黄河内蒙古河段冰情发展过程,并对水温、冰盖厚度、冰盖前沿发展和流量的模拟值和实测值进行了对比分析,模拟值和实测值吻合较好。本研究为黄河防凌提供科学依据和方法支撑,也为天然江河、人工渠道冰情全过程模拟提供了研究思路和技术手段。     

不同降雨工况下红黏土边坡持水响应规律与稳定性分析

以江西区域内典型红黏土边坡为研究对象,基于岩土非饱和渗流理论,建立红黏土边坡有限元计算模型,对4种典型降雨工况下红黏土边坡稳定性进行分析。结果表明,降雨强度、降雨持续时间均是影响红黏土边坡稳定性的重要因素;前期为常态时,边坡各参数指标均维持在初始稳定状态;降雨开始后,边坡安全系数呈减小态势,岩土体强度和稳定性降低,边坡中土体的孔隙水压力变大,体积含水量升高;越接近地表的土体降雨入渗响应越强烈,边坡不同位置处土体的降雨入渗影响程度依次为:坡肩>坡顶>坡面>坡脚>坡底;降雨入渗和互渗过程具有明显的滞后性,越靠近地表,孔隙水压力短期内变化越明显;土体干湿循环对边坡稳定性整体表现为负作用,且作用效果不可逆。     

On the predictability of the water-table variation in a ditch-drainage system

The irrigation in regions of brackish groundwater in many parts of the world results in the rise of the water-table very close to the groundsurface. The salinity of the productive soils is therefore increased. A proper layout of the ditch-drainage system and the prediction of the spatio-temporal variation of the water table under such conditions are of crucial importance in order to control the undesirable growth of the water-table. In this paper, an approximate solution of the nonlinear Boussinesq equation has been derived to describe the water-table variations in a ditch-drainage system with a random initial condition and transient recharge. The applications of the solution is discussed with the help of a synthetic example.Notations a lower value of the random variable representing the initial water-table height at the groundwater divide - a+b upper value of the random variable representing the initial water-table height at the groundwater divide - h variable water-table height measured from the base of the aquifer - K hydraulic conductivity - L half width between ditches - m ₀ initial water-table height at the groundwater divide - N(t) rate of transient recharge at time t - N ₀ initial rate of transient recharge - P N ₀/K - S Specific yield - t time of observation - t ₀ logarithmic decrement of the recharge function - T Kt/SL - x distance measured from the ditch boundary - X x/L - Y h/L - Y mean of Y - Y Variance of Y     

A new bivariate distribution in natural exponential family

We propose a new bivariate distribution following a GLM form i.e., natural exponential family given the constantly correlated covariance matrix. The proposed distribution can represent an independent bivariate gamma distribution as a special case. In order to derive the distribution we utilize an integrating factor method to satisfy the integrability condition of the quasi-score function. The derived distribution becomes a mixture of discrete and absolute continuous distributions. The proposal of our new bivariate distribution will make it possible to develop some bivariate generalized linear models. Further the discrete correlated bivariate distribution will also arise from an independent bivariate Poisson mass function by compounding our proposed distribution (Iwasaki and Tsubaki, 2002).Received March 2003     

顾客关系营销的应用研究

在综述关系营销内涵及其与传统交易营销的区别的基础上,对国内外企业顾客关系营销的应用进行了研究,分析了我国企业应用顾客关系营销过程中存在的问题,提出了应采取的对策。     

电话远程控制系统的实现

文章阐述了一种电话远程控制系统,并对其系统结构、各部分功能的实现和系统软件程序流程及主要软件功能进行了讨论,其摘机电路、挂机电路、密码电路简单实用;其受控对象如窗户状态、电器状态的反馈与控制电路稳定可靠。