滑坡转化为泥石流机理研究综述

对国内外有关滑坡转化为泥石流的机理的研究做了全面的综述,重点介绍了国外最新的研究成果,阐明了今后研究的方向.滑坡转化为泥石流机理的研究,处于滑坡动力学与泥石流形成学的交叉点,既是学科的边缘问题,也是学科的前沿问题.滑坡转化为泥石流的过程是一个和土体液化密切相关的流态化过程,是土体和水体强烈相互作用的结果.滑坡直接转化为泥石流的机理的两个核心问题是超静孔压的产生和超静孔压的保持.Iverson对这一问题的研究直接促进了滑坡流态化理论的发展,并形成了最新的泥石流运动模型--库伦混合流理论,是对传统的基于流变关系的泥石流模型的重大突破.土体中粘性颗粒对滑坡直接转化为泥石流过程的影响,需要进一步进行研究.滑坡转化为沟谷泥石流是一个更为复杂的过程,是今后研究的重点.     

Immune stimulation in fish and chicken through weak low frequency electromagnetic fields

A hypothesis is proposed how Low Frequency Electromagnetic Field (LF EMF) exposure can stimulate an immune response, based on recent insights in immunology. We hypothesize that the Immunent EMF treatment induces mild stress to cells, which then produce cytokines that function as alarms or so called danger signals for the immune system. In this way EMF treatment takes the place of multiplying pathogens, and the damage these cause, in the triggering of an immune response. In a first series of experiments in␣vitro common carp head kidney-derived phagocytes were used to determine ROS production as a measure for immune activation. Exposure to LF EMF signals (200–5,000 Hz) at 5 μT or 1.5 mT led to 42 or 33% increase in immune activity, respectively, compared to negative control values. EMF could also additionally stimulate chemically pre-stimulated samples up to 18% (5 μT) or 22% (1.5 mT). Significance of increase in ROS production in the total series was: p < 0.0001. In a second series of experiments in␣vitro commercial goldfish were used. Groups of fish were housed under equal conditions in at least four control tanks and 8–16 EMF-exposed tanks. Exposure was done with a predominantly vertical field at field strengths (rms) between 0.15 and 50 μT. Without treatment mortality was about 50% after 18 days, while the treatment at 5 μT reduced it to 20% on average. At field strengths 0.15, 0.5, 1.5, 5, 15 and 50 μT an equally strong effect was found. Reducing the field strength to 0.05, 0.06, 0.01 and 0.003 μT showed a gradually decreasing effect, which only at 0.003 μT is no longer statistically significant. Finally, in␣vitro experiments were done with 560 commercial broiler chickens exposed to infection pressure from coccidiosis. EMF exposure at 6.5 μT reduced intestinal lesions by 40% and improved feed conversion by 8%.     

农地非农化问题研究述评

土地是农业最基本的生产要素，随着经济的发展和城市化进程的加快，农地非农化规模越来越大，农用地的减少引发了我国粮食和生态安全等问题，“吃饭”与建设之间的矛盾日益突出。对此，国内外学者对农地非农化问题进行了大量研究，分析了我国农地非农化的现状和发展趋势，综述了部分学者的观点。     

Internal displacement in Burma

The internal displacement of populations in Burma is not a new phenomenon. Displacement is caused by numerous factors. Not all of it is due to outright violence, but much is a consequence of misguided social and economic development initiatives. Efforts to consolidate the state by assimilating populations in government-controlled areas by military authorities on the one hand, while brokering cease-fires with non-state actors on the other, has uprooted civilian populations throughout the country. Very few areas in which internally displaced persons (IDPs) are found are not facing social turmoil within a climate of impunity. Humanitarian access to IDP populations remains extremely problematic. While relatively little information has been collected, assistance has been focused on targeting accessible groups. International concern within Burma has couched the problems of displacement within general development modalities, while international attention along its borders has sought to contain displacement. With the exception of several recent initiatives, few approaches have gone beyond assistance and engaged in the prevention or protection of the displaced.     

引导和推进环保技术推广转化工作实现社会化

论述了环保技术推广转化工作实现社会化的必要性、存在问题,并重点提出了做好实现社会化引导工作的几个方面。     

进水氨氮负荷对污水生物脱氮过程中N_2O释放的影响

进水氨氮负荷是污水生物脱氮过程中N2O释放的重要影响因素。在稳定运行的序列间歇式活性污泥反应器(SBR)内,考察了进水氨氮负荷对污水生物脱氮过程中N2O释放速率、累积释放量和转化率的影响。结果显示,相比于缺氧段,进水氨氮负荷的增加对好氧段N2O的释放有较大影响,且N2O的释放速率、累积释放量和转化率均随进水氨氮负荷的增加而增大。当进水氨氮负荷从45.6g/(m3·d)增加到78.6g/(m3·d)时,系统的总N2O累积释放量和总N2O转化率增加并不明显,仅增加3.95mg、0.99百分点;而当进水氨氮负荷从78.6g/(m3·d)增加到117.6g/(m3·d)时,系统的总N2O累积释放量和总N2O转化率分别增加了25.24mg、4.49百分点。因此,在实际污水处理过程中,当进水氨氮负荷偏高(117.6g/(m3·d))时,系统的N2O释放量可能大幅增加,需要采取减少进水氨氮负荷的方法来避免N2O释放。     

三峡生态屏障区农户退耕受偿意愿的调查分析

运用参与式农户评估方法,对三峡生态屏障区内农户退耕还林的受偿意愿进行了调查.分析表明,退耕还林的生态效益受到普遍认可,但其可持续性令人担忧.1355份有效问卷中,愿意接受补偿的占74%,对未来生计的预期与土地相关性低的农户更愿意退耕.受偿意愿的形成具有明显的社会异质性和区域差异性.受访者性别、耕地面积、家庭年收入、帮扶形式、是否移民对受偿意愿值具有显著影响.屏障区平均补偿意愿为1014元/(亩×a).万州、秭归、渝北的受偿意愿值高于平均水平.建立基于区域的生态补偿标准和多元化的生态补偿方式,可以弥补目前均一型生态补偿标准和方式的不足,促进退耕还林工程和区域的可持续发展.     

Modeling the current-voltage characteristics of thin-film silicon solar cells based on photo-induced electron transfer processes

Power conversion efficiency of p-i-n type microcrystalline silicon (c-Si:H) solar cells has been analyzed in terms of sequential processes of photo-induced electron transfer. The effect of the excitonic state on the charged carrier generation has been studied compared to a conventional scheme in which only charged carriers are taken into account for the operation of the solar cells. A numerical model has been developed to calculate current-voltage characteristics of solar cells on the basis of two types of charged carrier generation processes (exciton process and charged carrier process). The light trapping effect due to a textured back surface reflector (BSR) was embedded in the numerical model by using the effective medium theory in combination with the matrix method in the field of the electromagnetic theory of light. As an application of this modeling, it was found that the reported data of the power conversion efficiency were not explained by the conventional charged carrier process model and that the combined model of the charged carrier process with the exciton process well explains the performance of the p-i-n type c-Si:H solar cells. In this way, the typical power conversion efficiencies were estimated to be 10.5% for the device (i-layer thickness: 1.8 m) with the BSR (period: 600 nm; height: 250 nm) and 8.6% for the device with the flat reflector under the condition that the fractions of the exciton process and charged carrier process were 60% and 40%, respectively.     

Modeling the current-voltage characteristics of thin-film silicon solar cells based on photo-induced electron transfer processes

Power conversion efficiency of p-i-n type macrocrystalline silicon (µc-Si:H) solar cells has been analyzed in terms of sequential processes of photo-induced electron transfer. The effect of the excitonic state on the charged carrier generation has been studied compared to a conventional scheme in which only charged carriers are taken into account for the operation of the solar cells. A numerical model has been developed to calculate current-voltage characteristics of solar cells on the basis of two types of charged carrier generation processes (exciton process and charged carrier process). The light trapping effect due to a textured back surface reflector (BSR) was embedded in the numerical model by using the effective medium theory in combination with the matrix method in the field of the electromagnetic theory of light. As an application of this modeling, it was found that the reported data of the power conversion efficiency were not explained by the conventional charged carrier process model and that the combined model of the charged carrier process with the exciton process well explains the performance of the p-i-n type μc-Si:H solar cells. In this way, the typical power conversion efficiencies were estimated to be 10.5% for the device (i-layer thickness: 1.8 μm) with the BSR (period: 600 nm; height: 250 nm) and 8.6% for the device with the flat reflector under the condition that the fractions of the exciton process and charged carrier process were 60% and 40%, respectively.     

社区化粪池污水能量转化估算与分析研究

以化粪池单元为研究对象,基于ADM1模型的反应过程,建立了社区化粪池污水能量转化核算模型(WeMax-STK模型),对污水能量在化粪池中的赋存、转化以及去向进行了分析,并评估了污水能量的回收潜力.结果表明,WeMax-STK模型整体可靠,模拟值与监测值的平均误差不超过24%,不确定性低于18%,模型准确率在70%以上.化粪池进水有机物转化为热能和内部微生物能量的比例约占进水总化学能量的17%,污水化学能的主要去向是转化为慢速降解基质的能量,化粪池内有机物转化为气态甲烷的能量仅占进水化学能总量的4%左右.污水热能的回收强度约4.6kWh/m³,热能回收潜力约为24%～25%,大约是污水化学能回收潜力的3～6倍.