Effect of building integrated photovoltaics on microclimate of urban canopy layer

Building integrated photovoltaics (BIPV) has potential of becoming the mainstream of renewable energy in the urban environment. BIPV has significant influence on the thermal performance of building envelope and changes radiation energy balance by adding or replacing conventional building elements in urban areas. PTEBU model was developed to evaluate the effect of photovoltaic (PV) system on the microclimate of urban canopy layer. PTEBU model consists of four sub-models: PV thermal model, PV electrical performance model, building energy consumption model, and urban canyon energy budget model. PTEBU model is forced with temperature, wind speed, and solar radiation above the roof level and incorporates detailed data of PV system and urban canyon in Tianjin, China. The simulation results show that PV roof and PV façade with ventilated air gap significantly change the building surface temperature and sensible heat flux density, but the air temperature of urban canyon with PV module varies little compared with the urban canyon of no PV. The PV module also changes the magnitude and pattern of diurnal variation of the storage heat flux and the net radiation for the urban canyon with PV increase slightly. The increase in the PV conversion efficiency not only improves the PV power output, but also reduces the urban canyon air temperature. © 2006.

Detailed thermal modelling of a tubular linear machine for marine renewable generation

A detailed lumped-parameter thermal model is presented for a tubular linear machine that has been designed for use in a marine environment. The model has been developed for a static machine, the worst-case thermal scenario, and is used to establish a rating for the machine. The model has been validated against a large range of experimental tests and shows good correlation to both steady-state and transient experimental results. The model was constructed from a mostly theoretical basis with very little calibration, suggesting that the techniques used are applicable in a more general sense. © 2013 IEEE.

贵州省小型甲壳动物新种和新记录

本文记述了1988年2～8月间采自贵州省的49种小型甲壳动物。其中,有枝角类29种,包括2新种——长刺尖额(氵蚤)Alona longispina Chen et Yang sp.nov,,透明锐额(氵蚤)Alonella hyalina Chen et Cao sp.nov.和2个国内新记录亚种——毛尾靴尾(氵蚤)Dunhevedia crassp cilio-caudata(Sovinsky,1891),短角平直(氵蚤)Pleuroxus trigonellus breviconis Brehm,19

Growth and properties of GaN on Si (111) substrates with AlGaN/AlN buffer layer by NH3-GSMBE

We describe the growth of GaN on Si (111) substrates with a AlGaN/AlN buffer layer by NH3-GSMBE. The influence of the AlN and AlGaN buffer layer thickness on the crack density of GaN has been investigated. It is found that the optimum thickness is 120 nm and 250 nm for AlN and AlGaN layers, respectively. The full width at half maximum of the GaN (0002) peak in the triple-crystal x-ray rocking curve measurement is about 15 arcmin.

Violet/blue emission from hydrogenated amorphous carbon films deposited from energetic CH3+ ions and ion bombardment

Considering the complexity of the general plasma techniques, pure single CH3+ ion beams were selected for the deposition of hydrogenated amorphous (a) carbon films with various ion energies and temperatures. Photoluminescence (PL) measurements have been performed on the films and violet/blue emission has been observed. The violet/blue emission is attributed to the small size distribution of sp(2) clusters and is related to the intrinsic properties of CH3 terminals, which lead to a very high barrier for the photoexcited electrons. Ion bombardment plays an important role in the PL behavior. This would provide further insight into the growth dynamics of a-C:H films. (C) 2002 American Institute of Physics.

一种用于网络取证分析的模糊决策树推理方法

网络取证是对现有网络安全体系的必要扩展,已日益成为研究的重点.但目前在进行网络取证时仍存在很多挑战:如网络产生的海量数据;从已收集数据中提取的证据的可理解性;证据分析方法的有效性等.针对上述问题,利用模糊决策树技术强大的学习能力及其分析结果的易理解性,开发了一种基于模糊决策树的网络取证分析系统,以协助网络取证人员在网络环境下对计算机犯罪事件进行取证分析.给出了该方法的实验结果以及与现有方法的对照分析结果.实验结果表明,该系统可以对大多数网络事件进行识别(平均正确分类率为 91.16%),能为网络取证人员提供可理解的信息,协助取证人员进行快速高效的证据分析.

信息安全产品安全保证量化评估方法研究

CC标准进行信息安全产品测评时,传统评估方法使用二值逻辑表示评价结果,只能定性评估,不能体现安全保证量的差异.本文提出依据保护轮廓构建评估框架的方法;将评估员对组件的评价定义为三角模糊数的形式;提出底线折衷法综合各组件评价得出TOE(评估对象)安全保证的量化表示.最后,通过实例表明这是一种CC标准框架正的可操作和较为合理的信息安全产品测评方法.

静电力场下高流速气固两相分离的研究

静电除尘器具有除尘效率高、设备阻力低，耗能少等优点，在工业领域得到广泛应用。但其烟气流速低，投资高、占地大的缺点在一定程度上限制了它的进一步应用。本文分析静电场中颗粒荷电及运动特性，讨论在静电场中高气流流速下的两相分离规律，期望为静电除尘器在降低投资方面的研究探索一些新思路。本文利用气体电离理论，对电晕电离现象进行了分析；利用电子碰撞电离理论，计算了电晕区的大小。通过计算，分析了粉尘在放电场中的荷电特性。对除尘器内的两相流的运动特性进行了数值模拟，分析了静电除尘器中的气流流速分布以及收尘电压、粉尘粒径、荷电场强和气流流速对驱进速度的影响并进行了公式拟合。通过实验，分析了提高烟气流速的情况下，随着荷电电压、除尘电压和收尘长度的改变，截面内粉尘浓度的变化规律。

Internal quantum efficiency analysis of solar cell by genetic algorithm

To investigate factors limiting the performance of a GaAs solar cell, genetic algorithm is employed to fit the experimentally measured internal quantum efficiency (IQE) in the full spectra range. The device parameters such as diffusion lengths and surface recombination velocities are extracted. Electron beam induced current (EBIC) is performed in the base region of the cell with obtained diffusion length agreeing with the fit result. The advantage of genetic algorithm is illustrated.

防护林防护成熟与更新

近一个多世纪以来，防护林科学的研究和发展，使全世界很多国家都越来越深刻地认识到防护林在人类的生活中有着与人类怎么样息息相关的重大作用（曹新孙等，1981）。随着对防护林这一特殊人工森林的研究和发展，各种功能的防护林相继分门别类地建立起来；诸如农田防护林，牧场防护林，水土保持林，水源涵养林，家畜防护林和住宅防护林等。其中以农田防护林的研究最为详尽。最早从事防护林研究的要属苏联，自1843年苏联就开始了营造干旱草原防护林（曹新孙等，1981），到1931年已建立起专门的研究机构（王广钦等，1987）中国营建防护林的历史也有一个多世纪，然而在我国正式进行科研还是从50年代开始的。在近几十年里，着重于农防林的效益、结构配置、营造技术，各种效应以及经营管理等研究，并取得了很大的成就。到目前为止，防护林具有相当水平的国家除中国外，还有苏联、美国、丹麦等（曹新孙，1983）。在国外苏联防护林的研究力量比较雄厚，从所查有关防护林的文献看（cab 文库，林业文摘）苏联关于防护林的文献占一半。