珠峰要“美容”

珠峰白雪皑皑却并不干净。一支由中、日、韩、尼泊尔及格鲁吉亚等国家44名人员组成的高山清扫队最近正忙着珠穆朗玛峰高海拔山区为珠峰“洗脸”。此次行动是由日本登山家野口健发起的。清洁队从珠峰6500米至8000米的地段中收集历年来各国登山队遗留下的煤气罐、氧气筒、罐头等垃圾，不幸遇难的登山队员的尸体也在寻找收集之列。在珠峰大本营，有十几个国家的18个登山队正在攀登这座世界最高峰，他们都很熟悉这支国际清洁队，绝大部分队员都要在海拔六七千米的高度工作。清洁队的翻译曾田小姐说：“去年已经为珠峰清洁过一次了。这两次活动都…     

台湾观感(二)

冬季到台北来看雨"冬季到台北来看雨,别在异乡哭泣。轻轻归来,不吵醒往事,就当我从来不曾远离……"流行于上世纪九十年代初的这首歌,出自一个80末90后都不太熟悉的台湾歌手,她叫孟庭苇。我问同龄的台湾朋友:"你们知道有     

电焊机应安装防触电装置

电焊机应安装防触电装置赵文玉，窦学庆焊接工艺在现代工业企业生产中应用非常广泛。几乎所有的工厂都离不开它。这种装置具有操作简单方便、连接牢固可靠、生产效率高等优点，而交流电焊机又以其焊机制造工艺技术简单、造价低、操作更方便而居选用的首位。所以，各企业在...     

Water quality characteristics of discharge from reforested loose-dumped mine spoil in eastern Kentucky

Surface mining is a common method for extracting coal in the coal fields of eastern Kentucky. Using the Forestry Reclamation Approach (FRA), which emphasizes the use of minimally compacted or loose-dumped spoil as a growth medium for trees, reclamation practitioners are successfully reestablishing forests. Yet, questions remain regarding the effects FRA has on the quality of waters discharged to receiving streams. To examine the effect of FRA on water quality, this study compared waters that were discharged from three types of spoils: predominantly brown, weathered sandstone (BROWN); predominantly gray, unweathered sandstone (GRAY); and an equal mixture of both aforementioned sandstones and shale (MIXED). The water quality parameters pH, EC, Ca, K, Mg, Na, NO-N, NH-N, SO, Cl, TC, suspended sediment concentration (SSC), settleable solids (SS), and turbidity were monitored over a 2-yr period on six 0.4-ha plots (two replications per spoil type). Generally, levels of Cl, SO, Ca, NO-N, NH-N, SS, SSC, and turbidity decreased over time. The pH for all spoils increased from about 7.5 to 8.5. The EC remained relatively level in the BROWN spoil, whereas the GRAY and MIXED spoils had downward trajectories that were approaching 500 μS cm. The value of 500 μS cm has been reported as the apparent threshold at which certain taxa such as Ephemeroptera (e.g., Mayfly) recolonize disturbed headwater streams of eastern Kentucky and adjacent coal-producing Appalachian states.     

基于交通流时间序列和层次聚类的应急航路划设

在地面管制单位服务能力完全丧失的紧急情况下,应急航路是保证一定数量航空器能够在失能空域中继续运行的重要手段之一。通过分析繁忙航路点的交通流时间序列特性,以相似交通流模式为依据,研究应急航路的划设方法。以此为基础,根据北京区域管制中心的实际航班运行数据,在简化的航路网中,基于欧氏距离的相似性度量,对不同航路点的时间序列进行层次聚类,通过设定距离阈值,并结合航路连接方式、冲突点等综合因素,划设北京某管制空域的应急航路,以保证少量航班在空域失能状态下继续安全运行,减小地面空管单位的管制压力。     

天津市政府召开“建立北方环保科技产业基地动员大会”

2000年6月9日市政府在天津礼堂召开了“建立北方环保科技产业基地动员大会”，国家经贸委副主任王万宾、资源司副司长赵家荣、科技部原副部长韩德乾、天津市副市长梁肃等同志出席会议并做重要讲话，全市各委、办、局、区县政府领导和企业代表300余人参加了会议。     

台湾观感(三)

台湾人的大陆印象在政治大学交换期间,我有幸参加了2010两岸青年学生论坛。两岸青年论坛在大陆举办过多次,而在台湾这却是头一遭。是因台湾方面有识之士深感:时代发展到了今天,两岸经贸关系日益紧密、民间交流日益频繁,     

Metal equilibration in laboratory-contaminated (spiked) sediments used for the development of whole-sediment toxicity tests

The equilibration and bioavailability of metals in laboratory-contaminated sediments have been investigated in order to provide better guidance on acceptable procedures for spiking sediments with metals for use in the development of whole-sediment toxicity tests. The equilibration rates of Cd, Cu, Ni and Zn spiked into three estuarine surface sediments with varying properties were investigated. Changes to sediment pH, redox potential, porewater and acid-soluble metals, acid-volatile sulfide and bacterial activity during equilibration, effects of temperature and disturbances following equilibration are reported. The addition of metals to sediments caused major decreases in pH and increases in redox potential as metals displaced iron(II) into the porewaters and added metals and iron (following oxidation) were hydrolyzed. The rates of equilibration of metals in porewaters varied considerably and were dependent on sediment and metal properties. For the oxic/sub-oxic sediments studied, metal-spikes of Cd, Cu, Ni and Zn appeared near equilibrium after 25-45, 10-15, 30-70 and 20-40 days, respectively. Acid-soluble metal concentrations decreased during the equilibration period indicating that the metals become more strongly associated with the sediments with time (less bioavailable). Bacterial activity was greatest in the sediment equilibrated at pH 7 and decreased following the addition of metals. During the equilibration period, bacterial activity increased in sediments equilibrated at pH 6, remained low in sediments at pH 8 and varied erratically in sediments at pH 7. Spiked sediments were shown to equilibrate more slowly at lower temperatures resulting in high porewater metal concentrations. Disturbances to equilibrated sediments because of sample manipulation caused significant iron(II) oxidation and losses of metals from porewaters. The importance of documenting spiking and equilibration procedures and carefully measuring and reporting sediment parameters is highlighted so that contaminant bioavailability and exposure pathways can be interpreted and organism sensitivity accurately determined. Recommendations are given for the preparation of metal-spiked sediments for toxicity testing purposes.