垃圾填埋场渗滤液及产生量的控制措施

城市生活垃圾卫生填埋是当今世界上使用最广的垃圾处理方式.从垃圾的收集,垃圾分拣,以及良好的填埋场设计及施工是保证其正常运转的先决条件.国外填埋技术的运用和研究起步较早,在各方面理论和实践已经相当成熟.中国进行垃圾填埋处置应在立足本国国情和实际情况的基础上,积极学习和引进国外成果,建立起自己的一整套规范,设计出经济、合理的垃圾回收、处理系统,以达到经济、社会、环境效益的统一.在分析了垃圾填埋场渗滤波的来源、渗滤液中污染物的特点及其变化规律,渗滤液量的计算,以及控制垃圾填埋场渗滤液的方法以后.围绕垃圾填埋场的污染特点提出了一些建议.     

Analysing countries’ contribution to climate change: scientific and policy-related choices

This paper evaluates the influence of different policy-related and scientific choices on the calculated regional contributions to global climate change (the “Brazilian Proposal”). Policy-related choices include the time period of emissions, the mix of greenhouse gases and different indicators of climate change impacts. The scientific choices include historical emissions and model representations of the climate system. We generated and compared results of several simple climate models. We find that the relative contributions of different nations to global climate change—from emissions of greenhouse gases alone—are quite robust, despite the varying model complexity and differences in calculated absolute changes. For the default calculations, the average calculated contributions to the global mean surface temperature increase in 2000 are about 40% from OECD, 14% from Eastern Europe and Former Soviet Union, 24% from Asia and 22% from Africa and Latin America. Policy-related choices, such as time period of emissions, climate change indicator and gas mix generally have larger influence on the results than scientific choices. More specifically, choosing a later attribution start date (1990 instead of 1890) for historical emissions, decreases the contributions of regions that started emitting early, such as the OECD countries by 6 percentage points, whereas it increases the contribution of late emitters such as Asia by 8 percentage points. However, only including the fossil CO₂ emissions instead of the emissions of all Kyoto gases (fossil and land use change), increases the OECD contributions by 21 percentage points and decreases the contribution of Asia by 14 percentage points.     

两广地区水域对酸雨的敏感性及其分区图

酸沉降对水生生态的影响程度,取决于降水中化学组分的输入量和地表水体对所输入的酸性物质的敏感性.湖泊对酸性沉降物影响的敏感性,决定于多种相互作用的因素,除酸沉降的强弱和影响酸沉降的气象因素外,还取决于湖泊的水文学及水化学性质、集水区的特点和土壤与基岩等诸因素.我国两广地区位于重酸雨区,酸雨频率高,酸度大,每     

稻田硝酸盐异化还原成铵细菌群落结构的垂向分布特性

硝酸盐异化还原成铵（Dissimilatory nitrate reduction to ammonium，DNRA）过程，可将土壤中的NO₃^-/NO₂^-还原成NH₄⁺-N以被作物吸收利用，有助于土壤中氮素的保存.选择位于广东韶关市和吉林安图县的两块稻田为研究对象，通过分子生物学方法和高通量测序技术，深入探究了两种稻田土壤（0~1 m）中DNRA细菌丰度和群落结构的垂向分布特性.结果显示：两种稻田土壤中DNRA细菌更多的存在于表层土壤（0~20 cm）中，丰度最低值均出现在深层土壤（90~100 cm）中，且表层样品群落结构的多样性大于深层样品；两个稻田样品间的群落结构体现出明显的空间异质性，安图稻田样品DNRA细菌的丰度和群落结构多样性均大于韶关稻田样品；其中，相对丰度较高的Anaeromyxobacter（28.67%）、Caldimicrobium（19.49%）、Nitrospira（10.90%）和Chthoniobacter（9.15%）是两个稻田中DNRA细菌群落组成中的关键菌属.相关性分析表明，总硫（TS）、有机质（TOM）、含水率（MC）、碳氮比（C/N）与DNRA细菌丰度之间均有显著正相关性（p<0.01，n=20），偏碱性、有机质丰富、氮源缺乏、碳源丰富且C/N较高的环境及适宜的含水率是稻田垂向生态系统中DNRA细菌适宜的生存环境.     

Energy flow through an organic agroecosystem in China

The energy flow in a traditional organic agroecosystem located in Hailun county of Northeastern China was analyzed for the years 1952–1954. For this energy analysis of the Hailun agroecosystem and human society, energy production was divided into 3 systems: crops, livestock and forestry.In terms of energy, this agroecosystem was self-sustaining. Human and horse power provided the major energy inputs. In the crop system, the energy input/output ratio was about 1:2. Fossil energy input into the total agroecosystem was less than 2% of the total. Based on only fossil energy inputs and crop outputs, the ratio was 1:107. The sources of food and household energy for human society came from the crop, livestock and forestry systems. The crop system provided more than 80% of the energy for this society.In addition to natural additions of N and P, legumes, other crop rotations and the application of human and livestock wastes to the land provided the nutrients for crop production. However, the agroecosystem was not self-sustaining in terms of some soil nutrients. Quantities of both nitrogen and phosphorus were calculated to be declining because of losses due to composting, storage, burning crop residues, exporting some harvests and soil erosion.     

定性物理模拟FM上下V拔长圆柱体

采用定性物理模拟的方法对FM上下V锻造法锻件心部的应力状态进行了实验分析,得出了当上砧宽比W/D_0=0.34时,锻件心部处于三向压应力的结果。实验结果与定量物理模拟相吻合。     

中线调水对襄樊环境影响的分析及对策

汉江襄樊段距南水北调取水口丹江水库最近,调水后所受到的的环境影响最直接。认真分析本地实际,采取有效措施和对策,使调水后的环境影响降至最低,以促进本地社会、经济、环境的协调发展。     

Process design of Synthetic Natural Gas (SNG) production using wood gasification

The process design of a 10–20 MW_th Synthetic Natural Gas (SNG) production process from wood has been performed. Combining process modelling and process integration techniques, this study proceeds via the following stages:

• thermodynamic modelling: mass, energy balances and simulation of the wood gasification, the methanation and the purification units;

• process integration that identifies the energy saving opportunities and prepares a thermo-economic optimization.

This work demonstrates that the process can transform wood into pipeline quality methane with a thermal efficiency of 57.9% based on the Lower Heating Value (LHV). The process integration study shows that the heat surplus of the process can be used to almost satisfy the mechanical work required by the process; only 7% of the mechanical needs should come from an external source.     

Alternative Non-market Value-Elicitation Methods: Are the Underlying Preferences the Same?

We advocate a more formal structural approach for comparing WTP for non-market or pre-test-market goods conveyed by fundamentally different preference elicitation mechanisms. Seven independent samples of respondents were asked to value the identical good. Elicitation methods include one actual purchase and six widely used hypothetical choice formats. Using a common underlying indirect utility function (and stochastic structure) allows data for different elicitation methods to be used independently, compared pair-wise (as in much of the earlier literature) or pooled across all samples in one unified model with heteroscedasticity across elicitation methods. Our differences in estimated WTP for the individual models are typical of earlier findings. However, pooled-data models that allow for heteroscedasticity reveal that while there are substantial differences in the amount of noise in the different samples, a common underlying systematic component of the preference structure cannot be rejected for at least four (and possibly five) of these seven elicitation methods.     

圈养亚成体大熊猫日粮粗蛋白表观消化率的初步研究

研究了7只1.5-4.7岁的亚成体大熊猫对23种日粮粗蛋白的表观消化率（ADCP），结果为37．86％－83．70％。分析表明，对1．5－2．5岁的大熊猫，粗纤维采食量与ADCP有极显著的负相关关系（图1）；对2．5－4．7岁的大熊猫。粗纤维采食量与ADCP没有明显相关关系（表3）。对1．5－2．5岁大熊猫，随竹粗蛋白占总粗蛋白比值升高，ADCP呈下降趋势（图2）；2．5－4．7岁的大熊猫，ADCP随竹粗蛋白比例升高而呈上升趋势（图3）；不同大熊猫ADCP还有个体差异。图3表3参10