GPS单频PPP电离层延迟改正模型探讨

针对电离层延迟会导致GPS单频精密单点定位精度严重缺失的情况,分别探讨了克罗布歇模型、格网模型和历元差分模型,并采用IGS跟踪站数据进行电离层延迟改正。同时根据改正后的单频精密单点定位精度,比较了这三种电离层延迟改正模型的改正效果。结果表明:历元差分模型的改正效果最好,其改正后单频精密单点定位精度可达到厘米级,能较好地符合实际应用要求。     

浅析建筑工程中的消防联动控制系统

随着社会的发展，建筑施工在全国各地迅速发展，在这些建筑工程当中，消防联动控制系统是整个建筑设施中非常重要的部分。消防联动控制系统不仅能有效的减少、杜绝、防止火灾的发生，更重要的是保证了人民的生命财产安全。本文在述说建筑工程总消防联动控制系统必要性的基础之上，分析目前这一系统的控制内容，探讨改善、解决的方法措施，以保证其作用的良好发挥。     

基于AIC方法的切换神经网络模型设计

将切换系统设计中的切换思想与神经网络相结合,构建了切换神经网络模型.根据模糊C均值（FCM）聚类方法将样本数据分为多组训练数据,每组数据对应训练一个单一神经网络模型,再利用赤池信息准则（AIC）制定相应的切换规则.根据输入数据特性,选择单一网络或多网络组合的输出作为模型输出,从而达到函数逼近目的.本模型更好地利用了各个子网络在特定区域具有较高逼近精度的特点.仿真结果表明,切换神经网络模型有较高的逼近精度.     

关于审计工作转型的几点思考

黄河三角洲高效生态经济开发区建设已上升为国家战略,山东半岛蓝色经济区建设迫在眉睫,都给滨州发展带来了千载难逢的历史机遇,同时,如何抢抓这一历史机遇,促进我市经济发展上规模、上质量,     

浅谈高校后勤员工的职业道德

加强高校后勤员工的职业道德建设，使后勤的服务让全校师生满意，明确了后勤员工工作职责，文明热情适应时代需要，勇于开拓创新的职业态度，是后勤工作面临的重大课题，这就要求工作人员加强职业道德修养，赢得师生的信赖，从整体上提升后勤工作的服务水平。     

JNDI技术及其使用方法

在Java EE项目中,各种应用组件种类繁多,其中JNDI(Java Naming and Directory Interface,Java命名和目录接口)是使用Java EE各种服务的基础。本文将对JNDI的结构进行分析,以及通过实例阐述其使用方法。     

解杨分离式立交连续箱梁施工简述

解杨分离式立交是运城绕城高速公路西南段的一座上跨分离式立交,桥梁中心桩号为K12＋239。重点介绍了该桥的主桥上连续箱梁混凝土浇筑以及张拉施工技术。     

锚网支护巷道顶板事故类型分析

本文对锚网支护巷道冒顶情况、特点、原因进行分析，并提出预防对策，避免冒顶事故的发生。     

Sperm viability in the reproductive tract of females in a population of Sceloporus mucronatus exhibiting asynchronous reproduction

Asynchronous reproduction is a common phenomenon in high-elevation populations of lizards from Central México. Sperm storage in the reproductive tract of females is the mechanism for making oocyte fertilization possible. Our study addresses questions related to functional oviductal sperm storage of females mating on different dates throughout the reproductive season. A population of Sceloporus mucronatus with copulation in the summer and ovulation in the fall was chosen for this experiment. Eleven females that copulated in the field during June and 13 females that copulated in captivity during August were maintained in the laboratory until parturition. The number of pregnant females and the litter sizes produced in each experimental group were indicative of the viability of the stored sperm. Sperm stored in the reproductive tract of females were able to fertilize eggs after 4 months. No significant differences were found in the number of pregnant females between the 2 experimental groups nor in the litter sizes that they produced. We found that the amount of time sperm were held in the female reproductive tract (ca. 3 months) had no effect on the capacity of sperm to fertilize eggs. Histological examination of 8 oviducts collected before the mating season eliminated the possibility of sperm storage from one year to the next. In this system, sperm retention could have evolved as a response mechanism to deal with the asynchrony between sexes in the reproductive cycles. However, we cannot rule out alternative hypotheses.     

浅议铁路通信设备的雷击危害及措施

铁路工作已经进入信息化时代,通信技术尤为重要.文章根据雷电形成以及特征,分析了雷电对铁路通信设备的危害以及原因,并提出相应的防雷措施,确保铁路运输安全运行.