高压静电分选Ag与PET的实验研究

为了提高高压静电分选Ag与聚对苯二甲酸乙二醇酯(polyethylene terephthalate,简称PET)的效率,寻求可产生较佳分选效率的电压、转速、极间距和电晕线角度。采用自制的线辊式静电分选机,通过单因素实验和部分因子实验,研究了不同条件下Ag与PET的分选效率。结果表明:将Ag与PET从二者混合物中有效分选出来的电压为25~30k V、转速为60~75 r/min、极间距为60~70 mm、电晕极角度为50~60°;当电压为30 k V、转速为75 r/min、电晕极距离为70 mm和电晕极角度为60°时,Ag的分选效率达到了最大值为99.60%,PET的分选效率也达到了最大值为99.98%,为线辊式静电分选机结构设计与参数优化提供了参考。     

黄河三角洲湿地生态保护红线区选划研究

滨海湿地具有非常重要的生态服务功能,针对其独特的地理区位和资源特征,划定区域湿地生态保护红线,对于生态红线制度的落实和滨海湿地开发利用管理具有重要意义.本研究以黄河三角洲湿地为例,基于陆海统筹原则,建立滨海湿地区域生态保护红线区选划评价指标体系,采用GIS空间分析方法实现对湿地生态服务功能重要性和生态环境敏感/脆弱性的评价,划定黄河三角洲湿地生态保护红线范围,并提出分级管控要求.     

Ergonomic interventions for prevention of work-related musculoskeletal disorders in a small manufacturing assembly line

This study involves performing improvements in workstation specification using a three-dimensional human modeling tool and proposing well-balanced work scheduling (WBWS) to prevent work-related musculoskeletal disorders (WMSDs) in a small manufacturing plant. To analyze risk factors of WMSDs, various tasks at 10 different types of workstation were evaluated with detailed motion analysis using a customized checklist. Questionnaires were administered to 27 workers to evaluate symptoms related to WMSDs. Revised workstation specifications were suggested based on anthropometric characteristics of workers using before–after analyses as an engineering control. Additionally, WBWS was proposed as an administrative control to avoid continuous physical stress on specific body parts in repetitive tasks. A software tool for WBWS was developed for convenient and easy application. The results of the study may aid managers in applying ergonomic interventions with time and cost savings, and enhance worker satisfaction and motivation due to improvements in working conditions to prevent WMSDs.     

地铁四线换乘枢纽高峰客流火灾疏散模拟研究

地铁换乘枢纽车站结构复杂、客流密度高,火灾情况下的应急疏散难度大,为研究地铁大型换乘枢纽火灾事故时的客流疏散模式,以四线换乘枢纽CGM站为例,使用building EXODUS软件,分别研究楼梯组、电梯、出入口和闸机组这4类设施无法使用时对乘客疏散时间的影响,以及各场景下乘客的疏散策略。考虑仅站厅乘客参与疏散、1辆列车上的乘客参与疏散、2辆不同线路列车上的乘客参与疏散这3种情况,共设置155个工况。研究结果表明:出入口对于疏散时间的影响较大;楼梯组次之;电梯和闸机组的影响明显小于前2者;同类设施中,由于设施位置及几何特征存在差异,各设施对于疏散时间的影响不同;随着疏散人数的增加,同一设施对于疏散时间的影响随之增加;所有出入口可以使用时,各线路独立疏散时效率较高;发生出入口火灾时,打开线路间换乘通道的防火卷帘门可降低所需疏散时间。     

双线地铁隧道下穿管道安全性对比研究

地铁与燃气管道等高危管道均为线性工程,地铁隧道下穿管道的情况不可避免,一旦因地铁施工导致管道泄漏,后果难以承受,管道沉降值是考量其安全性的关键指标。为对双线盾构地铁隧道下穿管线安全性进行预测,采用修正的Peck公式理论方法进行计算,并与数值模拟结果相对比,研究结果表明:双线盾构地铁隧道下穿管道安全风险可控,修正Peck公式及数值模拟法均能较真实地描绘地表以下任意土层的沉降槽曲线,进而可以比较准确地计算土体竖向沉降,可作为一种用于计算隧道开挖所引起管道竖向位移的方法。     

保温层下管道腐蚀监测系统及应用研究

为预防保温层下管道腐蚀带来的严重问题,必须采取有效措施进行腐蚀在线监测,以了解管道的剩余壁厚情况。在分析现有的腐蚀监测技术不足的前提下,基于γ射线数字扫描检测技术（GSDT）,研发了1套保温层下管道腐蚀在线监测系统,该系统可以实现对保温层下腐蚀管道剩余壁厚在线监测,并通过带保温层管道的检测试验和t-分布分析方法检验腐蚀监测系统的检测精度,最后以某化工企业为例,验证了该系统的有效性。结果表明:腐蚀监测系统可以实现对保温层管道剩余壁厚的监测,保温层和高密度介质不影响管壁厚度的测量结果,且使用所研发的腐蚀监测系统监测到的管道腐蚀速率与现场实际腐蚀速率基本一致。     

椭圆盒形拉延件合理毛坯的研究

利用保角变换由圆筒件拉延凸缘区的对数螺线推出椭圆盒形拉延件的滑移线方程 ,理论证明所求场满足边界条件和正交特性 ,并且与数值积分法的计算结果相当接近 ,最后给出了椭圆盒形拉延件合理毛坯的确定方法     

泰安台形变数字与模拟资料对比研究

泰安台是“九五计划”全国第一个数字化改造台站,改造了水管仪,又增添了伸缩仪、数字水平摆、垂直摆三种仪器,数字化改造已运行了六年多。本文利用四套仪器数字与模拟资料从漂移量、潮幅因子、记录精度、年变曲线进行对比研究,得出数字仪器代替模拟仪器的可行性。     

在役GIS内置特高频传感器校验方法研究

运行中的GIS内置传感器因其不易拆装,很难对其可靠性及有效性进行校验。根据GIS的结构特点以及特高频信号在GIS内的传输特点,提出一种对内置式特高频传感器的有效性进行校验的方法。通过在相邻传感器注入特高频信号并对信号幅值进行检测,通过检测及计算结果来判断特高频传感器的有效性,经现场验证,该方法简单有效。     

Impacts of Climate Change on the Distribution of Larix Spp. and Pinus Sylvestris and Their Climatypes in Siberia

Inter- and intraspecific effects of climate change were assessed for the dominant conifers of Siberia (60–140^∘E and 48–75^∘N): Larix spp. (L. sibirica, L. dahurica, and L. sukaczewii) and Pinus sylvestris . The approach employed a tri-variate (degree-days above 5 ^∘C, degree-days below 0 ^∘C, and a moisture index) estimate of the climatic envelope within which exists the actual ecological distribution of a species and their constituent climatypes (genotypes physiologically attuned to similar environments). Limits of the actual ecological distribution were approximated by reducing the climatic envelope according to effects of permafrost and interspecific competition. Climatypes were mapped within the climatic envelope according to the climatic interval that must separate populations for reasonable assurance of genetic differentiation. This interval was calculated from response functions that related 13-year growth and survival of a species to the difference in climate between the provenance of a climatype and the climate of numerous test sites distributed across Russia. Mapping species' distributions and their climatypes was done for the contemporary climate and for future climates predicted by the HadCM3GGa1 scenario of Hadley Centre. The results showed that if the forests of the future are to reflect the adaptedness of today, the distribution of species will shift and genotypes within species will be redistributed. Some contemporary climatypes are projected to disappear from Siberia while others common elsewhere would evolve. To mitigate these effects, climatypes should be transferred today to the expected future location of their climatic optima, a distance that is likely to approach 700–1200 km for these species.