宁波市砖混结构房屋安全检查与评估分析

在对宁波地区砖混结构房屋进行安全检查的基础上,分析房屋出现裂缝、倾斜等安全隐患的原因,对危旧房屋进行评估分析,并提出防治措施.     

体育中心周边区域城市设计初探

从城市设计的角度入手,对大连市体育中心及其周边区域的城市设计进行了研究,提出将体育中心周边区域作为体育主导功能的城市外延区,从而塑造整体性的城市空间景观,促进体育中心与周边地区的整体融合。     

高寒地区公路隧道渗漏水治理技术

针对高寒地区季节性冻融公路隧道环接缝处的渗漏水治理情况,提出在一般隧道渗漏水处理的基础上,采用低温自限温型电热带供热防止排水管冻结,治理高寒地区公路隧道环接缝渗漏水方法,解决了排水管内水的冻结问题,值得推广应用。     

嘉兴地区中小河流河道整治工程地质勘察技术探讨

近几年,嘉兴市中小河流整治工作如火如荼地展开。那么,如何提高河道的工程地质勘察技术水平呢？本文概述了嘉兴地区中小河流河道整治工程的现状,对嘉兴市河道整治工程地质勘察过程中的一些技术问题进行了分析和探讨。     

欠发达区域房地产业必须关注的问题

房地产业作为和经济发展直接相关的产业,在确立产业地位时,必须以当地经济发展情况而定,尤其是经济欠发达地区,要根据房地产业政策调整,从根本上促进就业与产业发展。本文就我国欠发达区域的房地产业,对相关问题进行了简要地探究。     

严寒地区乡村声景研究

声景有赖于人们在特定环境中对各种声音的评价,乡村声景的宁静特质为“聆听”提供了更多体验空间.基于声音与听者的关系,采用实地调查、声漫步、访谈问卷等方法,对环境声谱进行了案例分析,对主观数据的统计分析研究表明:随着年龄增长,村民对乡村环境常被感知到的声音声舒适评价先增高后降低;不同地区村民对交通声的评价无显著差异性:乡村人群对乡村环境中出现较多的交通声、家畜鸣叫声的声喜好与城市人群具有显著差异.     

基于扫描区间表示的不规则多边形快速定位算法及应用

不规则多边形定位算法是排料算法的重要组成部分,其效率对排料算法的性能有重要影响。基于扫描区间表示的不规则多边形定位算法因能适应任意复杂多边形而被广泛采用,但它存在计算量大的不足。通过深入研究基于扫描区间表示的多边形定位算法,该文从两个方面对其方法进行改进：首先提出候选平移位置矩阵的概念,进而实现定位扫描算法;然后通过最大跨度比较法快速排除一些不可能的行,从而通过减少定位扫描算法的调用次数进一步加速。该算法已应用于自主开发服装排料软件,多个实际衣片数据的测试结果证明了该文算法的有效性和高效性。     

两相区保温时间对QLT处理9Ni钢组织及性能的影响

将淬火态9Ni钢加热至670℃保温不同时间后水冷并回火.然后采用XRD法测定了实验钢中的逆转变奥氏体含量,进而分析了两相区保温时间对最终组织及性能的影响.结果表明:两相区保温时间为5 min时,其淬火组织特征与QT工艺较为接近;保温时间在10～30 min时,获得的组织与QT淬火后的组织产生明显的差异,组织中的大角度晶界显著增加,促进了回火过程中逆转变奥氏体的形成及钢低温韧性的改善;保温超过30 min后两相区淬火的特征逐渐减弱,钢的组织和性能再次趋近于QT处理,但当两相区保温时间更长时钢的低温韧性略有增加,这可能是由于钢中Ni元素的分布更加不均匀,促进了富Ni区形成更加稳定的逆转变奥氏体.     

Analysis of capacity and coverage region for Rayleigh fading MIMO relay channel

In this paper, we consider Rayleigh fading MIMO relay channel with channel state information at the receivers. First, we extend the previously obtained results for the ergodic capacity of uncorrelated and semi‐correlated MIMO channels and derive closed‐form expressions for the capacity bounds of MIMO relay channel. Next, we study this channel from a new point of view, maximizing coverage region for a desired transmission rate, and investigate the optimal relay location in the sense of maximizing coverage region. However, in order to overcome the mathematical complexity in desired transmission rate analysis, because of the randomness of the multiple antenna channel matrices, we evaluate this rate by using an existing exact formula and also by an approximation we find in the high signal‐to‐noise ratio regime. Numerical results show a perfect match between the Monte Carlo simulations and the obtained analytical closed‐form expressions and also confirm the effectiveness of our approach in cooperative vehicular communication for determining optimal relay location at which the coverage region is maximum. Copyright © 2013 John Wiley & Sons, Ltd.     

A modified rain attenuation prediction model for tropical V‐band satellite earth link

Radio wave propagation plays a very important part in the design and eventually dictates performance of space communication systems. Over time, the requirements of satellite communication have grown extensively where higher capacity communications systems are needed. Escalating demands of microwave and millimetre wave communications are causing frequency spectrum congestion. Hence, existing and future satellite system operators are planning to employ frequency bands well above 10 GHz. The challenge in operating at such high frequencies for communication purposes is that there exists stronger electromagnetic interaction between the radio signals and atmospheric hydrometeors. Such instances will degrade the performance of such high frequency satellite communication systems. The development of a revised model for a better‐improved rain fade prediction of signal propagations in tropical region is considered very important. Researchers and engineers can employ the model to accurately plan the future high frequencies satellite services. Copyright © 2014 John Wiley & Sons, Ltd.