层状半空间中凹陷地形对斜入射平面P波的2.5维散射

采用间接边界元法研究了层状半空间中凹陷地形对斜入射平面P波的2.5维散射问题。取无限长凹陷地形任一横截面,将边界以斜线单元离散,通过自由场反应分析,求得假想边界上各单元的应力响应。施加虚拟移动均布斜线荷载,求得应力格林函数。根据凹陷边界上的零应力边界条件确定虚拟移动均布斜线荷载密度,将自由场响应和虚拟移动均布斜线荷载产生的响应叠加起来,即得到问题的解答。通过与已有结果的对比,验证了本文方法的正确性。最后,以均匀弹性半空间和基岩上单一土层中凹陷地形对斜入射平面P波的2.5维散射为例,进行了数值计算分析,结果表明:凹陷地形的2.5维散射和二维散射之间存在明显差异;层状半空间中凹陷地形和均匀半空间中凹陷地形对波的散射作用存在显著差别。分析了造成差别的原因,并深入讨论了入射角度、覆盖层厚度和刚度对散射作用的影响。     

含镍废液中镍回收的研究

本文研究了强碱性条件下,以乙二胺为络合剂,用水合肼把二价镍离子还原为单质镍的方法。经过大量实验,镍粉的产率在99％以上,其纯度也在99％以上。通过这种方法,既回收了镍,又降低了对环境的污染,结果令人满意。     

荒漠植物红砂研究进展

主要综述了荒漠植物红砂的分布区及其生境、解剖学特征、种子萌发及幼苗生长影响因素、组织培养、生理生态特征、繁殖及育苗、分子生物学特性等方面的研究。简要阐述了修复和重建红砂植被的必要性,并着重研究了红砂种子萌发的影响因素及育苗技术的发展现状,在此基础上指出红砂研究中的不足之处,并对今后的研究方向提出了建议。     

Exposure to DDT and HCH congeners and associated potential health risks through khat (Catha edulis) consumption among adults in South Wollo,Ethiopia

Environmental Geochemistry and Health - Khat (Catha edulis) chewing is widespread in the region of East Africa. Even low levels of organochlorine pesticides (OCPs) in khat could induce public...     

浅谈污水设施运营的管理现状、发展方向及在云南的实践

通过对污水设施运营的实质内容、污水运营资质许可制度和污水设施运营管理现状及其发展方向的介绍,说明了污水设施运营在环境保护中的重要作用。     

Key aspects of successful rehabilitation after repeated or serious driving offenses

Objective: In Germany, license restoration after serious or repeated offenses requires a positive medical psychological assessment (MPA), a test to determine the driver's aptitude. Fulfilling the conditions necessary for a positive MPA often takes longer than the period of license revocation, which is perhaps due to the involvement of different personal, organizational, and environmental factors. To optimize the rehabilitation process, the present study analyzed the key aspects of successful rehabilitation after repeated or serious driving offenses.

Methods: After participating in the MPA, 1,631 subjects completed a questionnaire about rehabilitation efforts. The selection of items for this questionnaire was made according to our own prior research, interviews with problem drivers, and the diagnostic criteria for the MPA. Participants were asked when and from whom they obtained certain information and how relevant this information was for their success. In contrast to other studies, which used reoffense rates as a criterion for successful rehabilitation, we used a positive MPA result (positive, negative, or training) as the criterion for success.

Results: Just over half (52%) of the participants considered themselves optimally informed about the rehabilitation process. The others (47.4% of participants) judged the adequacy of information received as less than satisfactory. Offenders who did not partake in counseling before the MPA achieved a successful result only about half as often (37.1%) as those who did (70%) and were around 3 times as likely to have additional courses imposed upon them (21 vs. 7.6%). Of the offenders who received crucial and helpful information at an early stage, 62.4% attained a positive MPA at the first attempt (regardless of having attended any training courses). The success rate for the first attempt rose to 81% for offenders who were well informed at an early stage and participated in counseling before their first MPA.

Conclusion: The results clearly indicate that the provision of relevant information at an early stage combined with counseling has a beneficial influence on success rates for the rehabilitation process (an increase from 37.1 to 81%). As such, we recommend the introduction of obligatory license consultations, offered by MPA experts, involving a status assessment to customize offenders' rehabilitation and thereby provide more or less intensive guidance or coaching depending on offenders' characteristics throughout their progression through the MPA system.     

SNCR脱硝技术在循环流化床锅炉上的应用

分析了循环流化床锅炉特性和SNCR烟气脱硝技术的特点,通过CFD计算分析,对烟气和还原剂喷射混合过程进行了研究,得到了较理想的SNCR脱硝流场设计结果。在某75t/h循环流化床锅炉SNCR烟气脱硝工程上的初步应用结果表明,SNCR烟气脱硝效率可达55%以上,系统简捷、性能可靠,是循环流化床锅炉进行NOx控制的理想选择。