海河流域水资源规划工作思路及初步成果

海河流域水资源短缺,影响着整个流域社会经济的发展。为了更好地研究海河流域水资源的可持续利用,海河水利委员会组织的海河流域水资源规划工作已全面展开。目前,对流域的水资源量、水质状况、供用水现状等进行了调查分析,并取得了初步的成果。     

EXPERIMENTAL STUDY ON TOTAL UPLIFT FORCES OF WAVES ON HORIZONTAL PLATES

The total uplift forces of waves acting on horizontal plates are the important basis for the design of maritime hollow-trussed structures. In this paper, an experimental study on the total uplift forces of waves on horizontal plates was conducted by a series of model tests. The results show that the maximum total uplift forces do not necessarily occur with the maximum impact pressure intensity synchronously. On the basis of the test results, formation mechanism of the total uplift forces of waves as well as its influencing factors were analyzed in detail, and an equation for calculation of the maximum total uplift forces of waves on plates was put forward. Lots of test data shows the present equation is in good agreement with the test results.     

南宁市防洪堤防洪效益估算办法

在分析计算南宁市历次致灾洪水水位与淹没范围，淹没范围与经济损失之间的相关关系后，建立以物价增长指数和当地经济增长率为参数的合轴相关图表，若未来再遇致灾洪水，即可从曲线上读得致灾洪水造成的经济损失，供今后统计当年实际防洪效益参考     

Multi-Slice DCE-MRI Data Using P760 Distinguishes Between Metastatic and Non-Metastatic Rodent Prostate Tumors

An intermediate molecular weight contrast agent P760 was used to investigate the ability of multi-slice dynamic contrast-enhanced MRI (DCE-MRI) to distinguish metastatic from non-metastatic rodent prostate tumors. Non-metastatic AT2.1 and metastatic AT3.1 prostate tumors originally derived from the Dunning prostate cancer model were implanted on the hind leg of Copenhagen rats. Multi-sliced DCE-MRI data were acquired on a SIGNA 1.5 T scanner and analyzed using a recently developed empirical mathematical model. The P760 multi-slice DCE-MRI data in combination with the empirical mathematical model successfully distinguished between metastatic and non-metastatic rodent prostate tumors. Specifically, fitting the data with the empirical model showed that metastatic tumors had significantly faster contrast media uptake (p<0.001) and slower washout rates (p<0.01) than non-metastatic tumors     

Behavior of amine-modified urea–formaldehyde-bonded wood joints at low formaldehyde/urea molar ratios

Urea–formaldehyde-bonded wood products are limited to interior nonstructural applications because of their poor durability under cyclic moisture or humid environments. The stability of solid-wood joints and particleboards can be enhanced by bonding with urea–formaldehyde adhesives modified with di- and trifunctional amines at an effective resin formaldehyde-to-urea mol ratio (F/U) of 1.6; however, particleboard formaldehyde emissions were not improved over those from boards made with unmodified adhesives and were unacceptably high. The relative effectiveness of selected modifications was investigated at resin form aldehyde-to-urea (F/U) molar ratios of 1.4 and 1.2 Solid-wood joints and particleboards made with modified adhesives, an unmodified adhesive, and a phenol formaldehyde (PF) resin were subjected to cyclic soak-dry (cyclic stress) treatments and moist-heat aging. Formaldehyde emissions from particleboards were also determined. At F/U 1.4, the resistance of solid-wood joints made with modified adhesives to cyclic stress and moist-heat aging was equal to that of PF-bonded joints and superior to that of joints bonded with unmodified adhesive. The resistance of particleboards made with modified adhesives was greater than that of boards made with unmodified adhesive but less than that of PF-bonded board. Solid-wood joints and particleboards made with F/U 1.4 resins performed better than did those made with F/U 1.2 resins. Particleboards made with F/U 1.2 resins had formaldehyde emissions well below the standard, and room temperature aging or bonding at high temperature reduced emissions substantially. © 1994 John Wiley & Sons, Inc. 1

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

构建一个有线和无线(Wi-Fi)融合的家庭网络越来越急迫和重要

家庭网是接入网的延伸, 是解决端到端网络最后10米的瓶颈的重要方式,是保证用户体验质量的重要因素.MoCA技术利用家庭中的同轴,构建高速稳定有线网,延伸Wi-Fi接入点到每个房间,Wi-Fi连接安全可靠,可为每个房间提供高速可靠的有线和无线连接.     

万家寨引黄工程隧洞掘进与衬砌

山西省万家寨引黄工程的实践说明，在一定洞径范围内采用TBM法施工，六角形管片衬砌，能够实现高速度与高质量的统一，为大型跨流域调水工程提供了可借鉴的经验。本文对引黄工程采用TBM法施工不同阶段的质量状况进行了初步总结，重点讨论了止水设置，豆砾石回填灌浆，护盾形式，导向杆与连接销等主要结构问题。     

递阶偏最小二乘回归模型及其应用

偏最小二乘回归模型中包含所有原始选择的变量,当自变量较多时,因得到的模型结果十分庞杂而难以分析和解释。本文采用递阶偏最小二乘（Hierarchical PLS,Hi-PLS）回归方法,通过分层建立模型的方法有效解决了这一问题。工程实践表明,本模型精度较高,特别适用于大规模变量集合的回归分析。     

Antibiotic induced meningitis

The inositol lipid system (polyphosphoinositides and inositol phosphates) represents an important component of the cell signal transduction. Electroconvulsive shock (ECS) is known to activate cell signaling and lead to the release of second messengers. We tested the effects of daily ECS on the inositol lipid system and the generation of second messengers in vivo, by prelabeling the components of the system with [3H]myo inositol. The response to ECS was greater 30 sec after the sixth ECS, as compared to that obtained 30 sec after the first one. Also, rats killed 24h after the fifth ECS exhibited an increased PI labeling, as compared to rats handled for 6 days without receiving ECS. These results show that daily seizures (ECS-evoked) deeply modify the neuronal response to the stimulus, thus providing new information on the biochemical events involved in cell signal transduction during seizures.     

胶带输煤用金属检测器

本文介绍了一种金属检测器的结构、原理,它特别适合应用于胶带输煤系统中。