Water Quality Changes as a Result of Coalbed Methane Development in a Rocky mountain Watershed1

Abstract: Coalbed methane (CBM) development raises serious environmental concerns. In response, concerted efforts have been made to collect chemistry, salinity, and sodicity data on CBM produced water. However, little information on changes of stream water quality resulting from directly and/or indirectly received CBM produced water is available in the literature. The objective of this study was to examine changes instream water quality, particularly sodicity and salinity, due to CBM development in the Powder River watershed, which is located in the Rocky Mountain Region and traverses the states of Wyoming and Montana. To this end, a retrospective analysis of water quality trends and patterns was conducted using data collected from as early as 1946 up to and including 2002 at four U.S. Geological Survey gauging stations along the Powder River. Trend analysis was conducted using linear regression and Seasonal Kendall tests, whereas, Tukey’s test for multiple comparisons was used to detect changes in the spatial pattern. The results indicated that the CBM development adversely affected the water quality in the Powder River. First, the development elevated the stream sodicity, as indicated by a significant increase trend of the sodium adsorption ratio. Second, the development tended to shrink the water quality differences among the three downstream stations but to widen the differences between these stations and the farthest upstream station. In contrast, the development had only a minor influence on stream salinity, as indicated by that the stream electrical conductivity exhibited either no trend or a marginally significant positive trend. Hence, the CBM development is likely an important factor that can be managed to lower the stream sodicity. The management may need to take into account that the effects of the CBM development were different from one location to another along the Powder River.     

中高层砌块砌体结构Pushover分析研究

对3种不同中高层砌块砌体结构(分别为10层、15层和18层砌块砌体结构)进行大量时程分析,对结构的惯性力分布进行研究,提出一种新的适用于中高层砌块砌体结构Pushover分析的侧向力分布模式-抛物线型分布模式,并用该模式分别对3种砌块砌体结构进行Pushover分析。通过将Pushover得到的结构能力曲线与时程分析方法得到的结构能力曲线进行比较,将10层砌块砌体结构的Pushover分析结果与一座1/4比例的10层砌块砌体模型结构的振动台试验结果进行比较。比较结果表明:笔者所提出的侧向力分布模式适用于中高层砌块砌体结构的Pushover分析。     

黑龙江省暴雪天气分析和预报技术

分析表明，造成黑龙江省暴雪的低压天气系统不仅来自西北、偏西和偏南方向，而且还有在东北和日本海新生成的，其中又以西南和南来的居多；高空影响系统主要是低槽，其次是低涡，但降暴雪时多数是低涡；造成暴雪的锋面系统以暖锋和锢囚锋为最多。另外，从造成降水的成因和水平锋生这两个角度出发，给出了7个暴雪落区的温压场模型。850hPa温度、850hPa温度平流和拔海高度决定了降水（雨、雪）的性质。     

Climate change and changes in global precipitation patterns: what do we know?

The objective of this paper is to synthesize the large literature recording changing patterns of precipitation in the observed data, thus indicating that climate change is already a reality. Such a synthesis is required not only for environmental researchers but also for policy makers. The key question is the broad picture at major regional and continental levels. Some interesting conclusions for this survey are emerging. For example, the review shows increased variance of precipitation everywhere. Consistent with this finding, we observe that wet areas become wetter, and dry and arid areas become more so. In addition, the following general changing pattern is emerging: (a) increased precipitation in high latitudes (Northern Hemisphere); (b) reductions in precipitation in China, Australia and the Small Island States in the Pacific; and (c) increased variance in equatorial regions. The changes in the major ocean currents also appear to be affecting precipitation patterns. For example, increased intensity and frequency of El Ni?o and ENSO seem associated with evidence of an observed "dipole" pattern affecting Africa and Asia, although this time series is too short so far. But the changing pattern calls for renewed efforts at adaptation to climate change, as the changing precipitation pattern will also affect the regional availability of food supply.     

Paper fibers as a carbon source for the de novo formation of polychlorinated dioxins and furans

The formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs) from carbon that was produced by the pyrolysis of paper fibers and from wood charcoal was investigated experimentally. Fibers obtained from filter paper were pyrolyzed at 300° and 800°C to produce low- and high-temperature carbon samples. The two types of carbon and wood charcoal were mixed with silica (SiO₂) and trace copper oxide to produce three synthetic fly ash samples. Experiments to measure the formation of PCCDs/Fs from the three ash samples were conducted using a bench-scale reactor. The two carbon samples derived from paper fibers generated more PCDDs/Fs than was generated by the wood charcoal. The PCDDs/Fs generated by the low-temperature carbon and by the wood charcoal were dominated by the lower-chlorinated PCDFs. Such unique homologue distribution patterns are very similar to those generated by the open burning of household waste. The high-temperature carbon generated more highly chlorinated PCDDs/Fs. The effect of pyrolysis temperature on the de novo formation of PCDDs/Fs from residual carbon is discussed. Paper and paper products contained in household waste are likely to be the source of unburned carbon that contributes to high PCDD/F emissions in the open burning of household waste.     

国家地震紧急救援训练基地可控地震废墟设计(Ⅰ)--结构地震破坏模式

我国是一个地震多发的国家，地震灾害给我国造成了巨大的经济损失和严重的生命伤亡。专业化的震后紧急搜索救援能够最大限度地减少人民生命财产的损失，是防震减灾体系不可或缺的组成部分。通过大量的地震灾害实例，并借鉴地震灾害评估方法和建筑物抗震设计，对危害人类生命财产的建筑物震害的特征按照结构类型进行了详细说明，通过对这些地震中常见震害的了解和认识，为国家地震紧急救援训练基地的规划设计和相应搜索救援训练科目的设置提供依据。     

21世纪初我国粮食供需的新空间格局

利用2000-2003年县级统计数据,揭示21世纪初我国粮食供需的空间格局。我国粮食供需平衡以东西分异规律为主,其次是南北分异。地势第二级阶梯以东,主要余粮区分布最广,北方明显多于南方;胡焕庸线以西,常年缺粮区为主;两线之间,潜在缺粮区居多。东北地区、华北平原生产全国近70%的余粮。长江中下游以南地区既是我国温饱水平缺粮总数最多的地区,也是第三大余粮生产区。地势第二级阶梯上的农牧交错带,温饱水平缺粮总量列第二位,是我国粮食安全最脆弱的地区。上述地区主要位于环境变化敏感地带,粮食安全自然风险最大。因此,加强环境变化对粮食供需平衡的影响研究,对深入认识我国粮食供需平衡的稳定性具有重要的现实意义和理论价值。     

欧亚大陆生物质燃烧气团的输送特征及对中国的影响

利用1997～2003年ATSR卫星火点资料,采用前向气流轨迹模式及滞留时间分析方法,研究了欧亚大陆生物质燃烧排放的时空分布特征及主要生物质燃烧区域典型排放季节低层气团的输送特征,并与MOPITT一氧化碳卫星反演资料进行对比.结果表明,春季东南亚及印度半岛生物质燃烧排放的污染气团可对中国西南、华南及华东地区的大气环境造成一定影响,尤其是四川盆地、福建和台湾周边地区;中亚、东西伯利亚及蒙古高原生物质燃烧排放的污染气团主要受西风带影响而向东输送,但明显存在一条分支经中国东北向华北或更低纬度地区输送,并逐渐下沉至大气低层,在生物质燃烧排放剧烈的年份内能够对该地区的低层大气成分造成重要影响.     

偏心不耦合装药爆炸应力场研究及应用

中深孔光面爆破或预裂爆破质量对永久边坡的长期稳定性与安全性至关重要。利用偏心不耦合装药爆炸应力场的全息动光弹研究成果,对传统不耦合装药结构进行了改进,使高边坡光面爆破或预裂爆破效果得到明显改善,减少了因爆破效果不佳而造成悬、浮石滑落的事故隐患。并在实践中取得了一些有益的经验,可供同仁借鉴。     

澄江尖山河小流域不同土地利用类型地表径流氮、磷的流失特征

根据径流小区观测, 对澄江尖山河小流域不同土地利用类型地表径流中氮、磷的流失特征进行了研究. 结果表明:灌草丛和次生林都有较好的调节径流和减少土壤流失的作用,在相同的降水量下,坡耕地总产流量分别是人工林、次生林、灌草丛的1.58,12.45和5.52倍;而从产沙量来看,坡耕地的产沙量也远大于其余几种土地利用类型,坡耕地的总产沙量分别是人工林、次生林和灌草丛的8.41,53.06和41.90倍. 不同土地利用类型径流中的总氮、总磷的输出量差异显著,总氮、总磷输出趋势都表现为坡耕地＞人工林＞灌草丛＞次生林;不同土地利用类型径流小区侵蚀泥沙中的总氮、总磷输出量同样为坡耕地＞人工林＞灌草丛＞次生林,且坡耕地的输出量远大于其余几种土地利用类型. 相关分析表明,径流中带走的总氮量大于泥沙,磷的输出主要是以泥沙结合态为主,泥沙是磷的主要载体.