截干萌在银杏叶用园培养中的应用机理

研究了截干萌对银杏高生长,单叶干重、单株叶产量和黄酮含量的影响,结果表明：（１）第一次截干后,银杏高生长量比对照高,第二次截干后,距地３０ｃｍ截干的处理高生长也超过对照,约为对照的１２７％;（２）截干后,银杏单叶干重显著高于对照;（３）第一次截干后,银杏单株一显著对照,第二次截干后,３０ｃｍ截干高度的处理单株叶产量约为对照的１１２％,且随截干高度的增加,单株叶产量有随着增加的趋势;（４）截干后,银     

基于模型识别和电流极性的混合式双极型直流输电线路纵向保护

针对混合式双极型直流输电系统,结合模型识别和电流极性保护原理,提出一种新的输电线路纵向保护原理。分析故障网络发现:当逆变侧前端故障时,故障模型等效为电容模型(C模型),当逆变侧背面故障时,故障模型等效为阻感模型(RL模型);当整流侧前端故障时,整流侧故障电流具有正极性,当整流侧背面故障时,整流侧故障电流具有负极性。区内故障时,即逆变侧和整流侧的前端同时故障时,故障模型匹配C模型,同时故障电流具有正极性;当故障发生在区外时,即逆变侧和整流侧的前端不是同时故障时,逆变器侧的故障模型不匹配C模型,或者整流侧故障电流具有负极性。由此区分直流线路外部和内部故障。仿真结果表明,该原理可以补偿主保护,作为备用保护的改进。     

随机补货间隔期的多周期库存优化模型

针对供应商处于相对有利地位,零售商综合考虑各种因素决定他们补货量情况,研究了订货由零售商发起,且补货间隔期不受零售商控制情况下的多周期库存优化问题·在假设允许缺货、补货间隔期是独立同分布的随机变量的前提下,给出了补货间隔期服从一般分布的预期利润函数,通过确定最优补货量来有效地控制库存·在此基础上,又分析了补货间隔期服从两种特殊分布情况,并通过灵敏度分析说明了补货间隔期对其利润的影响·     

基于新意法理念的连拱隧道设计施工优化

通过采用三维地质建模技术建立乌龙山隧道的三维地质模型,基于新意法的核心理念通过FLAC3D程序对乌龙山隧道中导洞的全断面开挖过程进行了仿真分析,研究表明：在洞口超前管棚作用范围之内,全断面开挖时可无需对掌子面进行预加固;在管棚作用范围之外,通过对掌子面预加固后的不同工况模拟分析,得出玻璃纤维筋可以有效控制顶拱沉降以及减小掌子面挤出位移,用玻璃纤维筋加固掌子面后,顶拱沉降减少约40%,掌子面挤出变形减少约70%,极大的提高了掌子面的安全系数可实现每循环最大进尺三榀钢架（1.8m）的全断面快速开挖,并提出以不同搭接长度对应的掌子面挤出位移的曲线拐点来确定玻璃纤维筋的最小搭接长度。研究结果可为五级围岩的小断面隧道快速开挖提供借鉴。     

Discrimination of two kinds of sedimentary laminae in maar lakes of China

Varved lacustrine sediments have been found from high latitude to low latitude, even in tropical area. Paleoenvironmental and paleoclimatic research has increasingly relied on the use of varved sediments to provide high-resolution geochronologies and climatic reconstructions. However, a special depositional environment is necessary for varve formation and preservation. Generally, varves can be found in the sediments of maar lakes because of their special geological and hydrological environment. The preliminary research showed that a few carbonate laminations are developed in the Huguangyan maar lake, south China. They are poorly developed and not annual laminations, and may be related to periodically drought. Diatomaceous laminations are found in the maar lakes in northeast China. Diatomaceous laminations with cyclic nature corresponding with seasonal diatom blooming are the credible natural clock.     

春季九山湖细菌生理类群的分布与主要环境因素的相关性分析

本文研究了九山湖中7种细菌生理类群：产淀粉酶菌（AB）,产蛋白酶菌（PB）,有机磷细菌（OPB）,无机磷细菌（IPB）,硝化细菌（NB）及反硝化细菌（DNB）,产脂肪酶菌（LB）的分布,以及它们与主要环境因素的相关性,统计分析表明,春季,在九山湖中,OPB与总磷存在显著的正相关,NB与NH^ 4-N存在显著的正相关,DNB与NO^-2-N存在显著的正相关,LB与油脂间存在显著的正相关,OPB,IPB,NB,PB,DNB,AB与水温无显著相关性,而且除DNB与溶解氧（DO）存在一定的负相关外,其余细菌与DO存在不同程度的正相关。     

硬盘不能启动的原因分析及处理

在使用计算机的过程中,很多用户都遇到过计算机无法启动的情况,引起系统启动故障的原因有很多种,而其中跟硬盘相关的问题特别多,本文分析了硬盘不能启动故障的原因和处理方法.     

基于拓展Milgrom-Weber模型的全支付拍卖中的投标人竞价策略

对Milgrom-Weber模型进行了拓展,假定投标人数是服从Poisson分布的随机变量,利用不完全信息静态博弈方法,得到第一价格全支付拍卖中投标人的均衡报价函数,解决了实际中难以确定投标人数的困难.在此基础上,对投标人的目标函数进行了修正,引入两个参数反映投标人对获胜概率和净收益的偏好程度,得到了相应的投标人均衡报...     

A genome-wide association study identifies new susceptibility loci for non-cardia gastric cancer at 3q13.31 and 5p13.1

Gastric cancer, including the cardia and non-cardia types, is the second leading cause of cancer-related deaths worldwide. To identify genetic risk variants for non-cardia gastric cancer, we performed a genome-wide association study in 3,279 individuals (1,006 with non-cardia gastric cancer and 2,273 controls) of Chinese descent. We replicated significant associations in an additional 6,897 subjects (3,288 with non-cardia gastric cancer and 3,609 controls). We identified two new susceptibility loci for non-cardia gastric cancer at 5p13.1 (rs13361707 in the region including PTGER4 and PRKAA1; odds ratio (OR) = 1.41; P = 7.6 × 10(-29)) and 3q13.31 (rs9841504 in ZBTB20; OR = 0.76; P = 1.7 × 10(-9)). Imputation analyses also confirmed previously reported associations of rs2294008 and rs2976392 on 8q24, rs4072037 on 1q22 and rs13042395 on 20p13 with non-cardia gastric cancer susceptibility in the Han Chinese population.     

Erythropoietins from teleosts

The epo genes of many teleosts, including zebrafish, have been cloned following the first identification of nonmammalian EPO from fugu in 2004. The zebrafish (Danio rerio) animal model is well suited for both developmental and genetic analyses for studying vertebrate erythropoiesis. The purpose of this review is to provide an update of recent progress in research on teleost EPO with a focus on its structure, expression and secretion. The EPO receptor and the downstream JAK/STAT signaling pathway are also discussed. Received 29 April 2008; received after revision 23 June 2008; accepted 25 June 2008