关于提高挥发酚测定质量的探讨

探讨了在水样采集及分析测定过程中，如何保证分析结果的可靠性和准确性。     

对现行监测结果报告规则的粗浅看法

监测结果的报告是整个环境监测工作的结晶。它要求必须实事求是，才能为环境管理提供科学依据。而现行的监测结果报告规则。存在着人为夸大和缩小两方面的弊端，低于检出限的监测结果的表述模糊。不能真实的反映监测对象的实际情况，对人们了解环境质量状况及环境容量不能提供准确依据。给环境管理与环境规划等工作造成误导，本文以实例作了说明，并提出解决的方法。     

圆锥形零件冲压成形皱曲破裂成形极限的变化规律性

由外皱曲模型给出外不皱曲判据,依据它可计算出防外皱曲最小压边力的大小,作为防外皱曲的极限判据。由内皱曲模型给出内不皱曲判据,依据它可计算出防内皱曲最小压边力的大小,作为防内皱曲的极限判据。由破裂模型给出不破裂判据,依据它可计算出最大压边力的大小,作为防破裂的极限判据。结合上述外不皱曲判据、内不皱曲判据和不破裂判据,给出圆锥形零件冲压成形的成形判据和圆锥形零件冲压成形皱曲破裂成形极限的变化规律性。它们是材料参数M(n,r,σb,K,E)、设计参数D(D0,δ0,m,Kd,rd)和过程参数P(fb,fd,fα,η)的函数。     

交通噪声污染经济损失估算方法比较研究

目前闷内外对于噪声污染经济损失的研究还相当有限，且采用的方法也存在很大的差别。运用环境经济学的观点和方法，提出了估算噪声污染损失的3种常用方法；损害费用法、意愿型调查评估法和防护费用法，并对其进行了比较研究。     

板料成形过程系统分析

此文从系统的角度就板料性能、板料毛坯的展开计算、模具设计与制造、摩擦与润滑、应力应变分析等诸多方面对板料成形过程作了一般分析.可知板料成形过程是一复杂的,需要考虑系统中各个因素之间的相互关系和影响才能得到合理的板料成形件.并从有限元法的角度,建立了板料成形过程模型.     

岷江水系河水与沉积物中稀土,稀有元素背景值及其特征初探

报告了岷江水系河水及沉积物中８种稀土元素（Ｌａ，Ｃｅ，Ｎｄ，Ｓｍ，Ｅｕ，Ｔｂ，Ｙｂ，Ｌｕ）及８种稀有元素（Ｒｂ，Ｃｓ，Ｓｒ，Ｂａ，Ｓｂ，Ｔｈ，Ｓｃ，Ｕ）的背景值及其特征，并对元素的排列顺序及元素间的相关关系进行了初步探索，还列出了１６种元素在原水同积物中的相关矩阵及相互间的相关回归方程。     

氨气敏电极法测定大气中氨

以Ｈ２ＳＯ４（０．０５ｍｏｌ／Ｌ）和ＮＨ３（１．００ｍｇ／Ｌ）的混合溶液作吸收液，采用气敏电极测定大气中氨，发挥了离子选择电极所具有的快速、灵敏及测定范围宽等优点，保证了大气中低浓度氨测定的准确性和可靠性。实验表明，该方法检测限为０．０１４～０．０１８ｍｇ／ｍ＾２，精密度约为１４．３％（相对标准偏差），回收率在９７％～１０２％之间，经６个月实验室验证的结果，无论是精密度的变异系数或回收率的置信系数     

Driver speed selection on high-speed two-lane highways: Comparing speed profiles between uniform and differential speed limits

Objective: Although a considerable amount of prior research has investigated the impacts of speed limits on traffic safety and operations, much of this research, and nearly all of the research related to differential speed limits, has been specific to limited access freeways. The unique safety and operational issues on highways without access control create difficulty relating the conclusions from prior freeway-related speed limit research to 2-lane highways, particularly research on differential limits due to passing limitations and subsequent queuing. Therefore, the objective of this study was to assess differences in driver speed selection with respect to the posted speed limit on rural 2-lane highways, with a particular emphasis on the differences between uniform and differential speed limits.

Methods: Data were collected from nearly 59,000 vehicles across 320 sites in Montana and 4 neighboring states. Differences in mean speeds, 85th percentile speeds, and the standard deviation in speeds for free-flowing vehicles were examined across these sites using ordinary least squares regression models.

Results: Ultimately, the results of the analysis show that the mean speed, 85th percentile speed, and variability in travel speeds for free-flowing vehicles on 2-lane highways are generally lower at locations with uniform 65 mph speed limits, compared to locations with differential limits of 70 mph for cars and 60 mph for trucks.

Conclusions: In addition to posted speed limits, several site characteristics were shown to influence speed selection including shoulder widths, frequency of horizontal curves, percentage of the segment that included no passing zones, and hourly volumes. Differences in vehicle speed characteristics were also observed between states, indicating that speed selection may also be influenced by local factors, such as driver population or enforcement.     

混合气体爆炸性现场测试实验研究

为测定现场可燃混合气体的爆炸性,对比分析了国内外实验室爆炸极限的测定装置及爆炸性判定方法,设计研制了混合气体爆炸性现场测试装置。装置实现了爆炸性环境现场的自动采样、超高温点火、高速压力和温度测定及爆炸性自行判定。开展了丙烷、乙烯和液化石油气等典型可燃气体爆炸性实验,提出了基于压力和火焰温度变化相结合的气体爆炸性判定指标,改变了传统目测判定方式。研究结果表明:20 L球和1 L爆炸腔以爆炸压力提升来判定,比管式法测定的爆炸极限范围窄,以压力提升量5%~10%判定较适宜;1 L爆炸腔以爆炸过程温度提升量来判定,爆炸极限范围比以爆炸压力提升量判定宽,与目测观察的管式测定法相比,略宽于管式测定法和大部分文献数据。     

Reducing the risk of rear-end collisions with infrastructure-to-vehicle (I2V) integration of variable speed limit control and adaptive cruise control system

Objective: Adaptive cruise control (ACC) has been investigated recently to explore ways to increase traffic capacity, stabilize traffic flow, and improve traffic safety. However, researchers seldom have studied the integration of ACC and roadside control methods such as the variable speed limit (VSL) to improve safety. The primary objective of this study was to develop an infrastructure-to-vehicle (I2V) integrated system that incorporated both ACC and VSL to reduce rear-end collision risks on freeways.

Methods: The intelligent driver model was firstly modified to simulate ACC behavior and then the VSL strategy used in this article was introduced. Next, the I2V system was proposed to integrate the 2 advanced techniques, ACC and VSL. Four scenarios of no control, VSL only, ACC only, and the I2V system were tested in simulation experiments. Time exposed time to collision (TET) and time integrated time to collision (TIT), 2 surrogate safety measures derived from time to collision (TTC), were used to evaluate safety issues associated with rear-end collisions. The total travel times of each scenario were also compared.

Results: The simulation results indicated that both the VSL-only and ACC-only methods had a positive impact on reducing the TET and TIT values (reduced by 53.0 and 58.6% and 59.0 and 65.3%, respectively). The I2V system combined the advantages of both ACC and VSL to achieve the most safety benefits (reduced by 71.5 and 77.3%, respectively). Sensitivity analysis of the TTC threshold also showed that the I2V system obtained the largest safety benefits with all of the TTC threshold values. The impact of different market penetration rates of ACC vehicles in I2V system indicated that safety benefits increase with an increase in ACC proportions.

Conclusions: Compared to VSL-only and ACC-only scenarios, this integrated I2V system is more effective in reducing rear-end collision risks. The findings of this study provide useful information for traffic agencies to implement novel techniques to improve safety on freeways.