Panel LM unit root tests with level and trend shifts

This paper considers a Lagrange multiplier (LM) based panel unit root test that allows for heterogeneous structural breaks in both the intercepts and slopes of a series. We note that many popular time series variables are likely to exhibit changing means and/or trends over time. Given that the usual tests will depend on the nuisance parameters indicating the locations of the trend breaks, we adopt a transformation procedure that makes our new panel unit root tests invariant to the nuisance parameters. To illustrate the importance of the power gain provided by our test, we examine the convergence hypothesis using relative ratios of per capita health care expenditures in 20 OECD countries. Our results provide evidence that the convergence hypothesis is supported.     

Design Methodology and Area Sensitivity Analysis of Horizontal Subsurface Flow Constructed Wetlands

An approach is presented to satisfy the demand for simple criteria, guidelines and models for the preliminary sizing of horizontal subsurface flow (SF) constructed wetland systems. This approach eliminates time-consuming calculations and iterations by providing graphical solutions for wetland system sizing. Therefore, it can be used for the preliminary assessment of new or performance evaluation of existing subsurface flow constructed wetland systems. The validity of this methodology is checked with data from existing systems and is found to be quite satisfactory. This methodology is combined with simple equations predicting the maximum wetland capacity in summer, so as to assist designers in sizing installations in tourist areas with increased summer populations. Furthermore, based on this methodology, a sensitivity analysis is performed of the area requirements for wastewaters of various strengths and various design conditions and performance criteria. The results provide a useful overview to engineers and further simplify the design methodology of new subsurface flow constructed wetland systems.     

基于GIS的水电工程可视化辅助设计理论与方法

针对当前水电工程设计领域存在的计算机应用水平还有待于提高，设计过程复杂且不直观等情况，在探讨工程可视化辅助设计(VCAD)基本概念及其理论构成体系的基础上，提出了基于GIS的水电工程可视化辅助设计理论与方法，实现了直观方便的设计建模和设计过程的交互控制，以及设计成果的直观形象表达，从而有助于提高工程设计的效率和质量，也为大型水利水电工程设计提供了一种新的辅助手段．     

国有基层水管单位困境及其出路

针对贺州地区基层水管单位存在的农业水价低、水费征收难和经济困难等现状,对基层水管单位的出路进行了一些探索,提出了一些解决对策。     

三峡地下电站变顶高尾水洞水动力特性

在国内首次应用模型水轮发电机组对三峡地下电站变顶高尾水洞方案进行水力过渡过程试验研究。对水轮机导叶实行分段关闭 ,并求出了二段关闭的最佳拐点 ,试验证实了二段关闭对减小尾水管进口的负压和机组转速上升有明显的作用。通过有关水力参数的测试 ,认为变顶高尾水洞可以满足各项技术要求 ,是一个减少山体开挖、节省投资的新型设计方案。在地下电站中具有广泛的应用前景     

马家河水电站的设计

马家河水电站通过在马家河和毛家河上游分别建底栏栅坝和低拱坝 ,经各自的引水系统将水引至两河口汇合流入前池发电。本文介绍了电站的开发方案 ,厂区、引水工程和取水枢纽的布置和设计     

糯扎渡水电站机组主保护方案

结合糯扎渡水电站大型机组的发电机结构、发电机中性点引出方式及主接线对发电机主保护方案进行了分析研究，提出了发变组主保护方案，并初步确定了发电机中性点CT配置方案。同时也对主要的后备保护及异常运行保护进行了分析，并提出了设置方案。     

Connecting the second exhaust-heat boiler to the operating first one under the conditions of flow circuits of combined-cycle plants with two gas-turbine units and one steam turbine

Problems arising with connecting the second exhaust-heat boiler to the first exhaust-heat boiler under load in the case of flow circuits of combined-cycle plants of type PGU-450 are considered. Similar problems exist for two-boiler single-turbine units of type PGU-325 and for two-boiler single-turbine units of traditional steampower plants with an output of 200–300 MW upon connection of the second furnace of a two-furnace boiler to the operating first furnace. Analysis of the temperature-induced stressed state and of the cyclic strength of thick-walled elements of the steam-water conduit of PGU-450 and of two-furnace boilers of two-boiler single-turbine units with an output of 200–300 MW (the check valve, the inlet header of the water economizer) is used for determining the steam temperature differences in the high-pressure conduits to the steam turbine and the order of connection of the second exhaust-heat boiler to the operating fist one. Modes of enabling a two-boiler single-turbine unit of a combined-cycle plant, which are most “rigid” from the standpoint of thermal strength, are determined. __________ Translated from élektricheskie Stantsii, No. 2, February 2006, pp. 11–17.     

小型水电站联网改造应注意的几个问题

针对铜鼓县小水电站联网时存在的问题及其不利影响进行了分析，井提出了改进途径，指出小水电站的联网改造应立足安全，争取效益。