平煤十矿底板巷穿层钻孔瓦斯抽采模拟研究

为了降低平煤十矿己15-16-24130工作面运输巷掘进中的突出危险性，基于实际工程背景，考虑瓦斯抽采中的瓦斯运移及煤岩变形等因素，建立了瓦斯抽采气固耦合模型，并利用COMSOL Multiphysics软件对平煤十矿己15-16煤层的底板巷穿层钻孔瓦斯抽采方案进行数值模拟，研究了瓦斯抽采对于降低掘进过程中突出危险性的影响。研究结果表明:在己18煤层开挖底板巷对己15-16煤层进行穿层钻孔瓦斯抽采，瓦斯抽采180 d后，己15-16-24130工作面运输巷附近煤层残余瓦斯压力及瓦斯含量分别降至0.315 MPa和3.84 m3/t；将底板巷穿层钻孔瓦斯抽采方案进行工程应用，实测抽采后的残余瓦斯压力及瓦斯含量在0.32 MPa和3.17 m3/t，均小于平煤十矿煤与瓦斯突出防治规定的“双6”指标（残余瓦斯压力小于0.6 MPa，残余瓦斯含量小于6 m3/t），可有效降低运输巷掘进过程中的突出危险性。     

Horizontal lifelines – review of regulations and simple design method considering anchorage rigidity

Among the many occupational risks construction workers encounter every day falling from a height is the most dangerous. The objective of this article is to propose a simple analytical design method for horizontal lifelines (HLLs) that considers anchorage flexibility. The article presents a short review of the standards and regulations/acts/codes concerning HLLs in Canada the USA and Europe. A static analytical approach is proposed considering anchorage flexibility. The analytical results are compared with a series of 42 dynamic fall tests and a SAP2000 numerical model. The experimental results show that the analytical method is a little conservative and overestimates the line tension in most cases with a maximum of 17%. The static SAP2000 results show a maximum 2.1% difference with the analytical method. The analytical method is accurate enough to safely design HLLs and quick design abaci are provided to allow the engineer to make quick on-site verification if needed.     

注入式低温等离子体技术用于卷烟厂异味处理的效果研究

将注入式低温等离子体技术应用于烟厂制丝排潮和制丝除尘排放气体异味处理中,研究了注入式低温等离子体发生器参数对臭味浓度、非甲烷总烃和可检出典型有机物去除率的影响规律。结果表明:注入式低温等离子体发生器工作电压越高,注入处理烟道的氧化活性物种浓度越高,注入量越大,臭味浓度、非甲烷总烃和可检出典型有机物去除率也越高。选取合理的工作电压,臭味浓度去除率可达90%以上,非甲烷总烃去除率分别达到了83.8%(制丝排潮)和78.1%(制丝除尘)。     

Estimating the normal background rate of species extinction

A key measure of humanity's global impact is by how much it has increased species extinction rates. Familiar statements are that these are 100–1000 times pre‐human or background extinction levels. Estimating recent rates is straightforward, but establishing a background rate for comparison is not. Previous researchers chose an approximate benchmark of 1 extinction per million species per year (E/MSY). We explored disparate lines of evidence that suggest a substantially lower estimate. Fossil data yield direct estimates of extinction rates, but they are temporally coarse, mostly limited to marine hard‐bodied taxa, and generally involve genera not species. Based on these data, typical background loss is 0.01 genera per million genera per year. Molecular phylogenies are available for more taxa and ecosystems, but it is debated whether they can be used to estimate separately speciation and extinction rates. We selected data to address known concerns and used them to determine median extinction estimates from statistical distributions of probable values for terrestrial plants and animals. We then created simulations to explore effects of violating model assumptions. Finally, we compiled estimates of diversification—the difference between speciation and extinction rates for different taxa. Median estimates of extinction rates ranged from 0.023 to 0.135 E/MSY. Simulation results suggested over‐ and under‐estimation of extinction from individual phylogenies partially canceled each other out when large sets of phylogenies were analyzed. There was no evidence for recent and widespread pre‐human overall declines in diversity. This implies that average extinction rates are less than average diversification rates. Median diversification rates were 0.05–0.2 new species per million species per year. On the basis of these results, we concluded that typical rates of background extinction may be closer to 0.1 E/MSY. Thus, current extinction rates are 1,000 times higher than natural background rates of extinction and future rates are likely to be 10,000 times higher. Estimación de la Tasa Normal de Extinción de Especies     

Integrating soil carbon cycling with that of nitrogen and phosphorus in the watershed model SWAT: Theory and model testing

In this paper we describe and test a sub-model that integrates the cycling of carbon (C), nitrogen (N) and phosphorus (P) in the Soil Water Assessment Tool (SWAT) watershed model. The core of the sub-model is a multi-layer, one-pool soil organic carbon (S_C) algorithm, in which the decomposition rate of S_C and input rate to S_C (through decomposition and humification of residues) depend on the current size of S_C. The organic N and P fluxes are coupled to that of C and depend on the available mineral N and P, and the C:N and N:P ratios of the decomposing pools. Tillage explicitly affects the soil organic matter turnover rate through tool-specific coefficients. Unlike most models, the turnover of soil organic matter does not follow first order kinetics. Each soil layer has a specific maximum capacity to accumulate C or C saturation (S_x) that depends on texture and controls the turnover rate. It is shown in an analytical solution that S_x is a parameter with major influence in the model C dynamics. Testing with a 65-yr data set from the dryland wheat growing region in Oregon shows that the model adequately simulates the S_C dynamics in the topsoil (top 0.3 m) for three different treatments. Three key model parameters, the optimal decomposition and humification rates and a factor controlling the effect of soil moisture and temperature on the decomposition rate, showed low uncertainty as determined by generalized likelihood uncertainty estimation. Nonetheless, the parameter set that provided accurate simulations in the topsoil tended to overestimate S_C in the subsoil, suggesting that a mechanism that expresses at depth might not be represented in the current sub-model structure. The explicit integration of C, N, and P fluxes allows for a more cohesive simulation of nutrient cycling in the SWAT model. The sub-model has to be tested in forestland and rangeland in addition to agricultural land, and in diverse soils with extreme properties such high or low pH, an organic horizon, or volcanic soils.     

北京市铺装道路降尘污染特征及来源

为研究北京市道路降尘在不同季节的污染特征及来源,选取北京市4条典型道路得到64个采样点的道路尘样品,采集的道路尘样品经过预处理得到75 μm以下的颗粒物,经过再悬浮及实验室分析得到PM_2.5的粒径分布和化学成分谱.结果表明:不同采样高度及不同道路类型的颗粒物粒径大体分布规律一致,颗粒物质量频率存在三个峰值,分别为0.75 μm（微粒径）、2.50 μm（小粒径）、4.50 μm（大粒径）;各季节的降尘颗粒物的化学组分中质量分数最大的是元素,主要元素（含量>1%）季节变化为冬季>春季>秋季>夏季,元素富集因子法得到污染元素为Cr、Cd、Sn、Cu、Zn、Pb、As,双重元素为Bi、Ti、Ni、W、Mg、Ca、TI、Mo、V、Fe、Zr、Ba,其余16种为非富集元素;颗粒物中离子质量分数在夏季最大为9.31%,春季、秋季、冬季的离子质量分数相差不大,其中Ca2+、NO₃-、Cl-、SO₄2-占总离子质量的80%左右;碳素中w（OC）和w（EC）的季节变化均为夏季>秋季>春季>冬季,OC/EC[w（OC）/w（EC）]的季节变化规律为冬季>春季>秋季>夏季.不同季节w（OC）和w（EC）的相关性大小为夏季>秋季>春季>冬季.对PM_2.5中化学组分来源分析表明,污染元素受机动车和建筑尘影响较大,与机动车尾气相比,机动车磨损造成的污染也不容小视;燃煤影响一直存在,但供暖期污染有所改善.机动车尾气、建筑尘及土壤尘对离子均有贡献,在夏季土壤尘、建筑尘、二次反应的综合影响较大,春季土壤尘影响更为突出.碳在夏秋季节受汽车尾气和建筑尘的影响较大,夏季二次反应影响不大;冬季除气象因素外,燃煤和生物质燃烧也不可忽视;春季土壤尘影响较为突出.      

南通市降尘时空分布特征及影响因素

对2004年—2009年南通市降尘监测数据进行分析,结果表明,市区降尘污染较轻,年均值全部达标,在6年间呈波状变化态势;从各月分布来看,3—7月降尘污染较为严重;在各功能区中,受降尘污染程度从大到小依次为:居民区>工业区>商业交通区>文教区。提出,应继续推进城区企业工艺改造升级,加快燃煤锅炉淘汰;施工(运输)期间对易产生扬尘的建筑材料应采取密闭存储、设置围挡等有效措施并保证建筑垃圾及时清运、施工车辆及道路及时清扫冲洗;加大城市的绿化建设和道路的硬化建设,尽量避免道路开挖。     

阿坝州大骨节病和扶贫开发决策中AHP方法的应用

大骨节病防治和扶贫开发试点工作涉及阿坝州的经济、社会、生态等各方面，且州内各县、乡、村情况各异，众多具体措施关系复杂。为了提高决策质量，使试点工作取得“优化举措、重点突破”的效果，应用AHP方法建立了定量模型。     

高校应急管理全过程能力评价指标体系构建研究

高校应急管理全过程能力是高校公共安全的重要保障,建立科学合理的高校应急管理全过程能力评价体系是所有高校安全管理的重要课题。本文借鉴了国内外有关高校突发事件应急管理能力的研究成果,基于全过程理念,将高校应急管理过程分为事前预防与准备、事中处置和事后恢复三个阶段,因此高校应急管理能力应包括预防与准备能力、处置能力和恢复能力,从而构建出高校应急管理全过程能力的综合评价指标体系,体系包括3个一级指标,10个二级指标和33个三级指标,以期为提升高校应急管理水平提供有益的参考和借鉴。     

内蒙古农业灌区夏、秋浇的氮磷流失变化

通过对内蒙古农业灌区引黄灌溉的2次主要大规模灌溉（夏浇、秋浇）的跟踪监测,研究了农业灌区的氮磷流失情况.分析了2次灌溉期的各引水渠和排水渠中总氮（TN）、氨氮（NH4＋-N）、硝氮（NO3--N）、总磷（TP）、溶解性无机磷（DIP）、溶解性有机磷（DOP）、颗粒磷（PP）的变化情况.研究表明：夏浇时,由于植物吸收、灌水量小等因素,基本不产生污染.而秋浇期间,由于灌水量大、土地裸露成为非点源污染产生的主要时期.在对第8排域的TN、TP的连续监测中发现,排干沟中的总氮总磷含量基本维持在4.16mg.L^-1和0.1725mg.L^-1,且氮为主要的污染控制因子;排干沟中的N/P为24,排入乌梁素海中极易引起水华发生.结合河套农业灌区的自然条件、耕作方式等因素,综合分析了河套灌区在夏浇及秋浇时期的非点源污染产生过程及污染特点.为该地区非点源污染管理和控制提供科学依据.