广州地区办公建筑外围护结构的热工性能与节能分析

办公建筑的空调能耗是围护结构的温差传热、室内热扰、太阳辐射等因素动态综合作用的复杂结果。本文采用DeST软件对广州地区某办公建筑围护结构的各项节能措施的节能效果进行分析,结果表明:降低外窗的遮阳系数、外墙和屋顶的传热系数对减少建筑全年空调能耗和最大空调冷负荷是有利的,但降低窗的传热系数对减少建筑全年空调能耗和最大空调冷负荷不利。建议在办公建筑节能设计过程中,模拟计算全年能耗,确定能耗低且技术经济合理的方案,尤其要慎重考虑是否采用低传热系数的窗。     

基于分类线性加权的源-目标话者声音转换算法的研究

源-目标话者的声音转换是一种变换说话人声音特性的技术,它将源说话人的声音转换成另一个指定的目标说话人的声音.对源话者声道谱特性的修改是声音转换的关键之一.为了克服一般分类线性转换算法中分类不准确所带来的误差,本文引入了分类线性加权转换的策略,根据不同子类的转换函数对谱特性的贡献,赋予不同的加权系数,给出了一种基于GMM后验概率加权的线性转换算法.在微软汉语普通话语音数据库上做的四组对比实验表明,该算法在谱转换性能上均有不同程度的提高.     

舰船目标实时一维距离像研究

针对线性调频脉冲信号提出了舰船目标一维距离像实时成像算法,给出了系统工作原理,并结合舰船目标的实测数据对该算法进行了仿真分析,同时讨论了该算法在信号处理中的具体实现流程,最后给出了实时成像结果。     

英国既有非住宅建筑节能法规L2B一窥

介绍了此法规中的部分重要内容,如玻璃幕墙传热系数U值的计算公式,简单回收期的计算等.通过与我国<公共建筑节能设计标准>在窗墙比、围护结构传热系数等规定性指标限值方面进行比较和分析,发现其指标限值更加严格;并认为其所运用的方法概念,如用CO2排放量来进行权衡判断、以自我认证制度来完成节能工程,以及通过多种供选选项来辅助建筑师的节能设计等,对我国的建筑节能工作有一定借鉴意义.     

平面辐射空调系统在建筑节能中的应用

介绍了平面辐射空调系统在建筑节能中的应用。通过实例应用,讨论了优化建筑外围护结构子系统及毛细管平面式采暖供冷子系统的设计方法与注意事项。     

深层凝析气结蜡规律的软件模拟与实验研究

塔里木油田博孜区块属于典型致密砂岩凝析气藏,存在较为严重的蜡堵问题。通过对博孜区块井流物进行气藏条件下的相态与析蜡规律的实验研究,获得凝析气相态包络线相图,为凝析气井防蜡工艺提供理论支撑。以博孜104井凝析气为研究对象,采用可视化多功能高温高压流体PVT测试仪和可视化高倍显微固相沉积测定仪对其进行高温高压相态与析蜡规律的实验研究,并结合软件模拟结果和生产数据,对凝析油和析蜡情况进行分析。结果表明,凝析气随温度、压力变化过程中,产生气相区、气⁃液两相区、气⁃固两相区、气⁃液⁃固三相区等不同相态区域;利用实验结果对软件模拟结果进行校正获取了实验温度、压力以外的相态包络线,用于预判生产井处于不同生产阶段时析液与析蜡情况;博孜104井析液与结蜡区域位于地面输送管线,应做好相应的防蜡措施。     

信号包络在DSP系统中的实现

论述了采用Hilbert变换的方法提取信号包络的方法,对Hilbert变换进行了理论分析,并推导出在DSP(数字信号处理器)系统中实现的算法,通过MATLAB进行的仿真,结果表明达到了较好的效果。该方法可以替代硬件包络电路,具有很强的实际应用价值。     

Contingent Behaviours

Michelle Addington questions the accepted Modernist conception of the interior as a hermetically sealed envelope. She highlights the vicissitudes in attitudes that have existed over time to interior and exterior conditions by flagging up the 19th-century pursuit of ventilation and the permeable outside wall, which was pursued in the quest for public sanitation and a misguided belief in the ‘toxic’ interior. Copyright © 2009 John Wiley & Sons, Ltd.     

时频非平稳地震动模型及结构随机振动应用

地震动具有显著的时域和频域非平稳性,传统的均匀调制地震动模型不能充分表征时频两域的非平稳性,并影响结构随机振动分析的精准度。为了克服上述不足,建立由多峰平滑包络和非平稳噪声信号点乘而成的非均匀调制地震动模型,该模型能够在时域上充分反映地震动的波动和衰减特性,同时其频谱特征也与真实信号相接近。在此基础上,建立同时以时间和频率为变量的非平稳地震动演变谱随机模型。分析结果表明,以上两种模型在时域和频域的合成精度上均优于均匀调制模型。针对以上地震动随机模型的形式和特点,对传统结构随机振动响应求解方法进行改进。通过算例证明,按照均匀调制模型计算结构随机响应不能充分获得结构时频域的非平稳特性且结果偏于不安全,而利用两种改进模型可以获得更精确的结构响应概率特征和更细致的非平稳性演变过程。     

Echo signal envelope fitting based signal processing methods for ultrasonic gas flow-meter

The echo signal of the ultrasonic gas flow-meter is difficult to locate, and the computation of signal processing methods proposed by others is extensive which affects the meter’s real-time performance. Aiming at solving these problems the echo signal envelopes under different flow rates are analyzed. And three kinds of signal processing methods based on echo signal envelope fitting are proposed. The shape of the echo signal remains the “approximate spindle shape” as the flow rate increases, and the envelope gradient of the middle parts of the upper envelope’s rising section and the lower envelope’s falling section remains the same at different flow rates, so the mathematical models of the two sections are established to obtain the envelope gradient curves of the two sections. With the envelope gradient curves, the ranges of envelope and peak points that linearly distributed are obtained. The least squares fitting is performed on those peak points to obtain two feature straight lines for respectively representing the upper envelope’s rising section and the lower envelope’s falling section. According to the spatial characteristics of the feature straight lines, the points on the feature straight lines are selected as the feature points for quickly locating the echo signal. According to the offline verification and comparison, the best one of three kinds of signal processing methods is selected, and realized on the hardware system of the two-channel ultrasonic gas flow-meter. The transmitter of two-channel ultrasonic gas flow-meter is developed based on FPGA & DSP dual core structure. It utilizes the parallel processing capacity and logic control ability of FPGA to realize the controlling of the high-speed ADC & DAC and the storage of the data. At the same time, it adopts the high-speed computing capacity of DSP to implement the digital signal processing method. The gas flow calibration experiments were carried out in a national accredited testing agency to verify the effectiveness of the signal processing methods and system. The experimental results show that the improved signal processing method based on echo signal upper and lower envelope fitting can quickly and accurately locate the echo signal. And the measurable range of the ultrasonic gas flow meter based on this signal processing method is broadened to 10 m³/h to 1,300 m³/h, and the turndown ratio is broadened to 1:130.