Optical spectra and optical conductivities of iodine-doped polyacetylene

Reflection spectra of iodine-doped polyacetylene are studied for the wavenumber range 20–40 000 cm⁻¹ in order to find changes occurring in the electronic structure of the polymer upon doping. Three stages of doping are recognized from a spectral analysis of (CHI_y)_x : (1) 0 < y < 0.10, where the charged soliton domain is the dominant product; (2) 0.10 < y < 0.18, the free carrier is found where the hole and the unpaired electron are formed simultaneously; (3) 0.19 < y < 0.25, the free carriers begin to overlap each other and metallic properties become more evident. A new type of electronic transition associated with the electron transfer (charge resonance) between the hole states is found strongly in the far-infrared region. The origin of the metallic properties is discussed from a structural viewpoint.     

Collapse of braced tubes under impact loads

The dynamic response of diametrically braced metallic tubes under impact loading conditions is investigated both experimentally and numerically. The effects of strain rate and the initial collapsing mode configuration on the resulting force (acceleration) levels at the impacted end of the tube are discussed. Differences in energy dissipation characteristics of the braced tubes under quasi-static and impact loading conditions are described as functions of the bracing orientation.     

1990—2015年宁波市热岛效应特征与人口资源环境分析

针对目前城市中心越来越明显的城市热岛效应,基于Landsat系列数据和MODIS遥感数据,以宁波市中心城区为研究区域,运用地理信息系统技术和Pearson相关性分析方法,进行地表温度与其他因素的长时间序列的相关性变化分析.结果表明:1990—2015年间,宁波市中心城区热岛效应变化显著;其地表温度与NDVI呈负相关性,...     

Analytical and numerical studies of separated laminar two-phase flow in elliptical ducts of arbitrary axis ratio: Analytische und numerische Studien separierter laminarer Zweiphasenströmungen in Kanälen elliptischen Querschnitts mit beliebigem Achsenverh/:altnis

A solution to the momentum and continuity equations in stratified and annular two-phase laminar flow is presented for the cases of parallel plates, round and elliptical tubes. The velocity distribution, mean velocity, void fraction and pressure drop are evaluated in each geometry. It is shown that the pressure drop in elliptical tubes with the main axis of the ellipse in a vertical position is smaller than in a horizontal position. In general, the pressure drop is lower when the channel geometry is such that the contact area between the phases is smaller. The effect of liquid viscosity upon the pressure drop is stronger for low flow quality and decreases rapidly with an increase of the gas flow rate.     

生物炭农田应用的固碳减排研究进展

温室气体(GHGs)过量排放造成的全球气候变化问题受到广泛关注,农业活动是第二大温室气体排放源,减少农业温室气体排放刻不容缓.生物炭由生物质在高温限氧条件下热解炭化获得,其性质稳定、孔径丰富、富含芳香碳,因而减排增汇效果优异,具有参与农业自愿减排碳交易的显著潜力.然而生物炭固碳减排效果异质性大,影响因素复杂多样,因此有必要对其减排效应、影响因素和研究进展进行归纳总结.本文系统梳理了国内外与生物炭固碳减排相关的室内、大田研究和整合分析研究,同时采用CiteSpace软件进行可视化分析,探究了该领域的发展趋势和研究热点.基于国内外碳交易市场发展特点与程度以及相应配套政策总结了生物炭参与碳交易面临的机遇和挑战,并提出了相应的解决手段,为生物炭固碳减排研究的开展和生物炭农田应用项目参与碳交易提供了科学指导和建议.     

毛细管电泳脉冲安培法测定二氯苯酚的离解常数

基于毛细管电泳三脉冲安培检测技术,利用毛细管电泳中不同pH值条件下有效淌度(μeff)与缓冲溶液中[H ]的非线性关系,以及1／μeff缓冲溶液中[H ]的线性关系,测定了2,4-二氯苯酚(DCP)的离解常数。考察了三脉冲电位及时间、电解液的浓度、酸度、电泳电压及进样时间对测定的影响,得到了最优测定条件。以微盘铂电极为工作电极,Ag/AgCl为参比电极,三脉冲电位为:C1-300mV, t1200ms;E2600mV,t2100ms;E31000mV,t3100ms。该方法具有简单、快速、准确等特点。测得二氯苯酚的pK,为7.91。     

水利建设项目工程总承包机制优化研究

工程总承包是国际通行的建设项目组织实施模式,在水利建设领域起步较晚,目前的水利工程总承包机制尚不健全,影响了其优势的发挥。对水利工程总承包模式下工程参建各方组织界面问题进行科学有效的管理优化,构建以信任为基础的合同关系,制定适合工程总承包集约化管理规范,树立精益建造为主的工程总承包理念,进而提高水利工程总承包管理成效,促进水利工程建设管理水平提升。     

采用暴雨后期平均排除法计算排涝泵站规模研究

随着近年来城市化进程加速,城市排涝泵站建设需求激增,如何因地制宜确定排涝泵站规模尤为重要。淮北地区常用的方法有排模法、24 h降雨24 h 平均排除法和调洪演算法等。其中调洪演算法是确定排涝泵站规模比较准确的方法,但淮北地区多数排涝泵站所在河道缺少实测流量及产汇流过程线等数据,采用调洪演算法计算较繁琐。以七渔河泵站作为计算实例加以探讨,研究发现,采用最大 24 h 降雨时程分布 24 h 内暴雨后期平均排除法计算产汇流及排涝泵站规模方法便捷且计算精确,为淮北地区排涝泵站规模计算提供了一种新的方法。该方法适用于流域面积小于 50 km2 且缺少实测流量等数据的排水区域,已在阜阳市芦桥沟泵站和临泉县白沟站得到运用,结果科学可行。     

The control of sewage sampling using a portable computer

Software to control automatic samplers for sampling sewage flows has been developed for use on a Golden River Conquest Environmental Computer. The equipment is being used in Dundee as part of the UK National study currently underway investigating the polluting effects of sewage sludges that are washed out of combined sewers under storm conditions. Sewage is sampled automatically by samplers that are triggered from a control computer that is monitoring rising water levels in a sewer during storm and dry weather conditions. Increases in sewer flow cause entrainment of previously deposited sewage sludges which are potentialy very polluting if they reach a watercourse via a storm sewage overflow.Experience gained so far has shown that the Conquest computer is ideally suited to use in harsh sewer environments. Problems have been encountered, however, in maintaining power in the battery-operated computer sufficient to ensure that the requisite regular monitoring for rising water levels is being made. The solution to this problem has been to allow the computer to switch-off by going into a ‘sleep’ mode, awakening only to check sewer flow levels once every fifteen minutes. As a rise in level is noted, the ‘sleeping’ time is reduced and levels are monitored every one minute, with an ensuing fully operational state for the computer occurring only once levels reach a certain predetermined threshold.The polyFORTH software developed for this system is described, together with details of the sampling system and early results from the sewer flow quality monitoring study underway.The paper concludes that recent advances in the mathematical modelling of sewer flows and the associated quality implications for receiving watercourses have only been possible because of the parallel developments in computational systems for use in harsh environments such as sewers.     

电网继电保护及故障信息管理系统设计

为提高电网故障分析能力及继电保护的管理水平,提出了继电保护及故障信息管理系统,该系统由主站、分站、子站通过电力调度数据网连接组成。介绍了继电保护及故障信息管理系统的总体框架、功能定位以及主站和子站的设计方案。着重讨论了不同情况下保护及故障录波装置如何接入子站、子站与监控系统的互联方式、整个系统的安全防护方案,通过比较,提出了保护间接接入子站、子站单独组网的推荐方案。