In vivo screening to determine hazards of nanoparticles: Nanosized TiO2

A single-species laboratory test with terrestrial invertebrates was used to identify the hazard of nanosized TiO₂. Feeding parameters, weight change, mortality, and the activities of catalase and glutathione-S-transferase were evaluated after 3 or 14 days of dietary exposure. The effects of nano-TiO₂ were dependent on exposure concentration and duration, total consumed quantity, size and pre-treatment of particles. The intensity of a response was ruled by duration of exposure and not by consumed quantity of nano-TiO₂ or exposure concentration as expected. The response to nano-TiO₂ is described as threshold-like. The exposure concentrations 10-1000 μg TiO₂/g dry food (1.35-1025 μg of total consumed quantity of TiO₂/g animal wet wt.) were identified as safe for tested species after tested exposure period. We conclude that the response to nanoparticles is different from that of soluble chemicals therefore these two types of data should be interpreted and processed differently.     

厌氧序批式反应器内挥发性脂肪酸积累特性研究

小试规模的厌氧序批式反应器（ASBR）,通过人工配水,研究了启动3个月时间以及一个运行周期内反应器内挥发性脂肪酸（VFA）的积累情况,并通过分析期间产甲烷活性的变化说明了控制VFA积累的重要性。经过近120 d的运行,乙酸和丙酸的最大比产甲烷活性分别提高了1.8和2.2倍,说明反应器的启动过程即是微生物群落的优化和选择的过程,ASBR的抗冲击的能力较强说明随启动的进行和种群的优化,活性污泥凝聚性能增强,对VFA的降解能力增强。     

Comparing the impacts of hiking, skiing and horse riding on trail and vegetation in different types of forest

Nature-based tourism in protected areas has increased and diversified dramatically during the last decades. Different recreational activities have a range of impacts on natural environments. This paper reports results from a comparison of the impacts of hiking, cross-country skiing and horse riding on trail characteristics and vegetation in northern Finland. Widths and depths of existing trails, and vegetation on trails and in the neighbouring forests were monitored in two research sites during 2001 and 2002. Trail characteristics and vegetation were clearly related to the recreational activity, research site and forest type. Horse trails were as deep as hiking trails, even though the annual number of users was 150-fold higher on the hiking trails. Simultaneously, cross-country skiing had the least effect on trails due to the protective snow cover during winter. Hiking trail plots had little or no vegetation cover, horse riding trail plots had lower vegetation cover than forest plots, while skiing had no impact on total vegetation cover. On the other hand, on horse riding trails there were more forbs and grasses, many of which did not grow naturally in the forest. These species that were limited to riding trails may change the structure of adjacent plant communities in the long run. Therefore, the type of activities undertaken and the sensitivity of habitats to these activities should be a major consideration in the planning and management of nature-based tourism. Establishment of artificial structures, such as stairs, duckboards and trail cover, or complete closure of the site, may be the only way to protect the most sensitive or deteriorated sites.     

N掺杂TiO_2光催化剂的制备及其H_2O_2改性的研究

以钛酸四丁酯为前驱物,采用水解沉淀法制备了N掺杂TiO_2光催化剂和H_2O_2改性的N掺杂TiO_2光催化剂.实验表明,H_2O_2改性的N掺杂TiO_2光催化剂的最佳制备条件为:氨水(质量分数28%)加入量20 mL,焙烧温度500 ℃,H_2O_2(质量分数30%)加入量2.0 mL.日光下,N掺杂TiO_2光催化剂及H_2O_2改性的N掺杂TiO_2光催化剂在反应90 min时的活性红紫去除率达99%,它们对活性红紫的去除率远高于P_(25)TiO_2光催化剂.H_2O_2改性的N掺杂TiO_2光催化剂中N质量分数比改性前明显提高,制备的两种催化剂中不仅含有N元素,同时还含有C和H元素.     

大型活动生物恐怖应急处置研究与系统开发

针对非传统安全威胁的现状及其应急处置中的主要问题,以典型的非传统安全事件-大型活动举办过程中生物恐怖事件为背景,通过比较分析,给出了生物恐怖的定义;从大型活动生物恐怖应急指挥与处置的角度,通过应急处置业务流程分析,提出了大型活动生物恐怖事件应急处置的系统框架;根据系统框架和处置功能分析,基于三维GIS和AJAX技术开发了大型活动生物恐怖应急处置原型系统,对复杂的应急处置体系进行了分层模块化和可视化,可为应急救援部门制定更为详细的救援方案和应急决策提供技术参考。     

成都市土壤天然放射性核素的外照射水平估算研究

利用IED22000A便携式微机多道能谱仪对成都市区土壤的天然放射性核素进行了直接就地测量,估算出天然环境放射性核素^238U、^232Th、^40K的比活度范围分别为10.37～77．19Bq／kg、17,85～225．74Bq／kg、284．83～892．67Bq／kg;外照射指数范围为0．16—0．8;离地面1m高的空气吸收剂量率均值为83．23nGy／h;1外照射年有效剂量当量为0．34～0．70mSv;等效镭浓度的变化范围是59．06-386．45Bq／kg,均值为164．15Bq／kg。各项指标均在容许范围之内,因而成都市属于外照射水平的安全区域,人居环境不受影响。     

云南近期3次中强震的天文背景

分析了澄江地震至丘北地震间云南发生的3次中强震时的天体位置、地球自转与太阳活动等天文背景,分析结果表明,尽管这3次地震的震级都较小,但都发生在震中所受引潮力变化较大时刻和太阳活动局部下降时段。     

一个新的拓扑指数用于芳烃化合物溶解度、分配系数及生物毒性的研究

在分子拓扑理论的基础上,提出了一个新的拓扑指数Yx,并用Yx研究了芳烃化合物的溶解度、分配系数及生物毒(活）性,给出了相关方程。结果表明,新方法计算方便,物理意义明确,预测值与相应的实验值较吻合。     

六安流动地磁测量异常的映震能力探讨

将安徽省六安地区流动地磁测线 12个流动地磁测点的∑ |δfi|异常与安徽中西部地震活动性作对比分析 ,初步结果为 :12个流动地磁测点的∑ |δfi|值较大 (∑ |δfi|≥Fu) ,一年内安徽中西部地区的地震活动性增强 ;反之 ,则安徽中西部地区的地震活动性较弱。此方法在地震的中短期预报中有一定的实用意义。