通过尘障后的激光束特征

从辐射亮度方程出发,推导了在大粒子近似条件下,激光束通过尘障以后约化通量密度和漫射通量密度的表达式,并在四个常用激光波长上作了数值计算.结果表明,当散射粒子浓度较大时,尘障后表面上的漫射通量密度通常比约化通量密度高很多,且散布在较宽的范围内.随着光束远离尘障,漫射通量密度迅速减小,约化通量密度重新占据主导地位.     

项目研究法在培养学生创新素质中的应用

如何密切理论教学与工程实践的联系是目前高等教育提高教学质量,提高学生实践能力需要思考的一个重要问题。以《工业通风与除尘》课程为例,采用项目研究法对这一问题进行了的讨论。通过设定具体条件,让学生在课堂学习过程中,将理论与实践紧密结合起来,并将课程的各部分内容有机结合起来,从而为应用创新型人才培养在课程教学上提供一些思路。     

灰霾天气对人体健康的危害

灰霾是颗粒物和气体污染物导致的可察觉到的能见度降低的污染天气现象。近年来,随着城市化进程的快速发展,城市大气污染加剧,灰霾天气也随之增多。介绍了灰霾天气的形成过程、化学成分及其危害,并从流行病学等角度出发,对灰霾天气对人体健康效应的研究成果进行了综述。     

静电旋风除尘器性能的研究

在分析离心和静电分离综合作用的基础上，建立了修正的平衡轨道模型．利用该半经验模型．可较好地说明静电分离和离心分离作用两者对静电旋风除尘器除尘性能的影响．利用所建立的除尘实验装置，系统地进行了静电旋风除尘器性能实验研究，着重分析了除尘器进口风速、工作电压、电晕极型式和布置方式等因素对除尘器性能的影响．     

Field Measurement of Dermal Soil Loading Attributable to Various Activities: Implications for Exposure Assessment

Estimates of soil adherence to skin are required for assessment of dermal exposures to contaminants in soils. Previously available estimates depend heavily on indirect measurements and/or artificial activities and reflect sampling of hands only. Results are presented here from direct measurement of soil loading on skin surfaces of volunteers before and after normal occupational and recreational activities that might reasonably be expected to lead to soil contact. Skin surfaces assayed included hands, forearms, lower legs, faces and/or feet. Observed hand loadings vary over five orders of magnitude (roughly from 10^–3 to 10² mg/cm²) and are dependent upon type of activity. Hand loadings within the current default range of 0.2 to 1.0 mg/cm² were produced by activities providing opportunity for relatively vigorous soil contact (rugby, farming). Loadings less than 0.2 mg/cm² were found on hands following activities presenting less opportunity for direct soil contact (soccer, professional grounds maintenance) and on other body parts under many conditions. The default range does not, however, represent a worst case. Children playing in mud on the shore of a lake generated geometric mean loadings well in excess of 1 mg/cm² on hands, arms, legs, and feet. Post-activity average loadings on hands were typically higher than average loadings on other body parts resulting from the same activity. Hand data from limited activities cannot, however, be used to conservatively predict loadings that might occur on other body surfaces without regard to activity since non-hand loadings attributable to higher contact activities exceeded hand loadings resulting from lower contact activities. Differences between pre- and post-activity loadings also demonstrate that dermal contact with soil is episodic. Typical background (pre-activity) geometric mean loadings appear to be on the order of 10^-2 mg/cm² or less. Because exposures are activity dependent, quantification of dermal exposure to soil will remain inadequate until data describing relevant human behavior (type of activity, frequency, duration including interval before bathing, clothing worn, etc.) are generated.     

浅谈藏族古代关于世界本源“元素说”的物理思想

古代时期的藏族人对他们生活在其中的世界的起源本质、事物的运动,以及层出不穷的自然现象进行过种种观察和思考,从而形成了他们对自然界的根本看法和认识,其中关于世界本原的"元素说"较有代表性。     

施工扬尘环境保护税相关问题探讨

施工扬尘环境保护税的征收，不仅要从征收依据、征收对象等两个层面来把握政策确定性，而且还要从推进生态文明建设、建设美丽中国视角来认识其实施的必要性。施工扬尘环境保护税的征收模式有天津、南京和扬州等三种典型模式，这些模式各有其特点与优势。考虑到施工扬尘属于无组织排放，且监测困难，因此，建议现阶段施工扬尘环境保护税征收应以核定征收的方式为主。     

论作为藏书家的何良俊

明代何良俊以博学多才名闻江东，这与其酷爱藏书不无关系。父辈存书的遗留，为何良俊藏书奠定了基础；家中刻坊的便利、对书籍不遗余力的购买，更是极大地丰富了他的藏品。何良俊一生所交多书画、藏书名家；朋友之间的相互交流，不仅丰富了藏品，更提高了其书画鉴赏水平。藏为所用，是何良俊藏书的主要准则。作为有明一代著名戏曲理论家，他特别留意对金元杂剧的收集和整理，并把一些珍贵藏品刻印，以惠泽后人。然好景不长，先是倭寇焚毁藏书楼，大部分书籍归于祝融；后又因家境渐落，不得不鬻书以存。其中，书画藏品多为好友朱大韶、项元汴所得。     

“费”的博弈论观

:各种形式的乱收费直接导源于政府公共支出的不断膨胀。从理论上来看 ,收费过程表现为一种各经济行为主体相互之间的博弈 ,并且都存在各自的优超策略从而实现均衡。现实中的博弈虽然有异于理论上的博弈 ,但同样存在各自的优超策略 ,从而同样可以实现优超策略均衡。在收费制度的改革过程中 ,政府政策的目标区域即是这种处于纳什均衡的博弈结局状态空间     

"糟粕"概念在张载哲学中的重要意义--兼论张载的"理一分殊"是负的"理一分殊"

张载的“道”指的是气化,这与二程的理相差很大,是一种非常独特的观点。也正是在这一独特思想的基础上,张载提出了其负的理一分殊的体用论。张载认为,天地法象,皆神化之糟粕(负的理一分殊);在张载看来,一旦走出“形不形”之关节点,所形成的“天地法象”“万物形色”,都只不过是神之糟粕而已。张载进一步认为,虽然万物形色为糟粕,但它实是太虚本体的藏身之地;只要在糟粕上点睛以太虚本体,则糟粕即转化为精华。