Corporate occupational exposure limits: An example of a strategy

Occupational exposure limits (OELs) developed by authorities play a key role in the implementation of programs to protect workers against hazardous chemicals. Unfortunately, many hazardous substances do not have OELs or the OEL could be outdated. To assure the health of the workers, it is therefore useful for companies to develop corporate OELs. An inhouse strategy will be presented hereafter. Expertise in toxicology, industrial hygiene, and occupational health should be available within the company and clear selection criteria for substances are needed. A corporate OEL is only developed for hazardous substances (e.g., carcinogenic or reprotoxic) with a high potential for worker exposure when an appropriate national OEL or threshold limit value is not available. The methodology to calculate corporate OELs is based on the existing methods for national or community OELs and also on the guidance from the European Union's (EU) regulation on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH). For carcinogenic substances with a nonthreshold mode of action, there is always a residual chance that a cancer develops even when the exposure of workers is low. To establish an OEL for these substances, the “German traffic light model” is recommended. It is pragmatic, defines an unacceptable, tolerable, and acceptable risk level when workers are exposed to these substances, and determines risk management for exposure reduction. Overall, the professional practice to develop OELs is a good example of corporate leadership to proactively protect the health of workers.     

Light transmission through intraocular lenses with or without yellow chromophore (blue light filter) and its potential influence on functional vision in everyday environmental conditions

In this research the factors used to evaluate the light transmission through two types of acrylic hydrophobic intraocular lenses, one that contained yellow chromophore that blocks blue light transmission and the other which did not contain that filter, were defined according to various light condition, e.g., daylight and at night. The potential influence of light transmission trough intraocular lenses with or without yellow chromophore on functional vision in everyday environmental conditions was analysed.     

红外辐射大气透过率研究综述

随着红外技术的不断发展和在军事上的广泛运用,红外辐射在大气中的传输研究越来越受到关注.大气透过率是研究红外辐射传输的重要参数.基于红外辐射大气传输的基本理论结合近年来国内外的研究成果,从理论研究和软件平台2个方面对计算大气透过率的研究进展进行了综述,并探讨了复杂气象条件对大气透过率的影响,最后进行了总结和展望.     

小风和静风状态下TSP大气扩散模式的理论推导

以移动烟团积分模式为基础,采用数学模型分析法,从理论上导出了小风和静风状态下的TSP大气扩散模式。该模式描述了重力沉降和地面不完全反射对颗粒物大气扩散过程的影响;与现有的大气扩散模式体系完全相容,可以方便地应用于小风和静风状态下TSP地面浓度的预测计算     

铬天青S-铝(Ⅲ)-聚乙二醇4000体系的共振散射光谱及其应用

在pH5 0的NaAc HAc缓冲溶液及非离子表面活性剂聚乙二醇 40 0 0存在下 ,铬天青S与铝 (Ⅲ )形成络合物微粒体系 ,在 40 0nm和 5 30nm处出现两个较强的共振散射峰 .共振散射光强度与Al(Ⅲ )的浓度在 0 0 84— 0 84μg·ml- 1 范围内呈良好的线性关系 ,考察了适宜的反应条件及共存物质的影响 .建立了一个共振散射光谱测定水中Al的方法 ,其结果与分光光度法一致 .     

非饱和土壤轻油污染多相流研究进展

轻油泄漏到地下后 ,在非饱和土壤中水、气、油三相相互作用、相互影响 ,共同构成多相流体系统。在简要分析轻油污染问题的产生、危害以及轻油泄漏在地表以下运移方式的基础上 ,介绍并总结了近些年来国内外土壤轻油污染有关的多相流研究方面的进展 ,包括国外的模型研究成果、国内外试验研究方法和研究成果 ,并指出目前研究中存在的问题和需要进一步探讨的方向     

芳纶1414在光辐射下的安全化研究进展

芳纶1414是重要的高性能芳香族聚酰胺纤维且在个体防护领域应用非常广泛,但在光老化作用下力学性能下降非常明显,从而影响其使用寿命。本文从耐光性研究、耐光性能评价方法、耐光防护三个方面综述了芳纶1414在光辐射下的稳定性和安全化研究进展。耐光性研究方面,国内外对于芳纶1414在光辐射下的损伤机理的解释,尚难达成一致;耐光性能评价方法方面,现有的评价方法不能直观地反映出光老化作用对织物实际性能的影响情况,从防弹性能的保留率角度对其耐光性能进行评价是未来研究的方向;耐光防护方面,溶胶-凝胶法是目前应用最为广泛的织物抗光老化整理方法,但该法也仅限于对芳纶织物表面处理,对里层纤维的紫外防护有限,如何提高芳纶织物整体抗紫外性能需进一步深入研究。     

AlN覆铜板盐雾环境下的退化行为研究

目的 研究AlN覆铜板在盐雾环境下的性能退化及其微观机制。方法 采用交替喷雾和干燥方法对AlN覆铜板进行15周期的中性盐雾试验,并在第1、3、6、10、15周期时检测其相关性能。主要通过击穿电压测试、介电性能测试和导热性能测试等方法,分别评价AlN覆铜板的电绝缘特性、介电损耗及导热系数,并通过扫描电镜和能谱测试对试样表面/截面微观形貌和元素变化进行分析。结果 AlN覆铜板导热系数和击穿电压随盐雾试验周期的增长而逐渐退化,最大退化率分别为13.2%和73.8%。介电损耗明显增加,盐雾试验15周期后,在低频区域的最大值约为1.3。Cu电极发生明显腐蚀,生成大量绿色腐蚀产物,导致表面Ni-P镀层脱落失效。H₂O分子扩散进入AlN陶瓷内部,在局部区域造成陶瓷水解,逐渐形成微裂纹。结论 盐雾试验过程中,Ni-P镀层逐渐开裂剥落,Cu电极表面最终形成大面积疏松多孔的腐蚀产物层。H₂O、Cl^–、Na⁺等逐渐溶解扩散进入AlN陶瓷,导致陶瓷中空位、裂纹、杂质缺陷浓度增加,二者都会增强导热过程中的声子-缺陷散...     

空气中粉尘粒子的侧向散射效应研究

目的从米散射的基本理论出发。对有关的粉尘粒径的米散射效应进行研究。方法所用的方法主要通过对米散射理论的深入学习、研究,运用Matlab编程软件对0~5μm之间的微粒进行散射光强和散射相函数的计算,得到不同粒径的散射光强、散射相函数,然后利用COMS相机对激光拍摄得到其散射图像,利用散射图像的灰度值与0~5μm之间加权平均的粒子散射相函数值作对比,比较程序实现的可行性。结果得到了0~5μm之间微粒的散射光强以及相应的散射相函数以及激光灰度图像在72°到108°的灰度值。结论通过图像灰度值与散射向函数的曲线对比,证明了程序的可行性。     

Effects of visible light radiation on macrophyte litter degradation and nutrient release in water samples from a eutrophic shallow lake

Visible light is a major fraction of the solar spectrum; however, information on visible light radiation of macrophyte detritus is lacking. In this study, we conducted a microcosm experiment to assess the effects of visible light radiation on degradation of two litter species: Potamogeton malaianus (P. malaianus) and Phragmites australis (Ph. australis). This research represents an investigation of mass loss, microbial activity and nutrients released over a period of 168 days. Overall, we found that visible light radiation had significant effects on litter decomposition, but it did not affect the microbial activities which degrade cellulose and lignin. The decomposition rate order of the three components in P. malaianus and Ph. australis in treatments was: cellulose?>?hemicellulose?>?lignin. The visible light radiation mainly affected the degradation of lignin, which is the primary compound in litter susceptible to photodegradation. The exposure to visible light radiation up to 17.6?Wm^?2 stimulated the dissolved organic carbon release and reduced the molecular weight to less reactive. Meanwhile, no obvious difference in nutrient contents (TP, TN, NO₃–N, NO₂–N, and NH₃–N) was observed among different visible light intensities. The results of this study contribute to better understanding of the photochemical behaviour of macrophyte litter in shallow lakes.