Stochastic Technology, Risk Preferences, and Adoption of Site-Specific Technologies

A model of farmer decision making is developed to determine the extent to which uncertainties about soil fertility and weather affect the value of site-specific technologies (SSTs) using jointly estimated risk and technology parameters. Uncertainty can lead risk-averse farmers to apply more fertilizers and generate more pollution than in the certainty case. Ignoring uncertainty and risk aversion would overestimate the economic and environmental benefits of SSTs and underestimate the subsidy required to induce adoption. Accounting for uncertainties and risk preferences might explain the low observed adoption rates of SSTs. Improving the accuracy of SSTs would increase the incentives for adoption.     

小氮肥清洁生产实践

文章介绍了沅江市氮肥厂废水闭路循环、尾气回收、废渣综合利用等工程,并介绍了该厂的生产工艺、污染源分布及排污特点。     

纯氧曝气的研究进展

介绍了纯氧曝气的生化机理、应用领域、供氧方式、污泥性能等以及它与普通空气曝气相比在技术、经济方面显示出的优越性。随着纯氧曝气的发展和国家新标准增加了脱氮除磷方面的排放要求，使得纯氧曝气在城市污水处理老厂的改造和新厂的建设中具有很好的前昔。     

Cost Uncertainty and Unilateral Abatement

Unilateral abatement is sometimes advocated in order to set a good example that will make other countries follow. The aim of this paper is to investigate whether existence of correlated cost uncertainty provides an incentive for a country to undertake unilateral abatement. The theoretical model is driven by two main mechanisms; first, a learning effect, as the follower country might reduce its risk premium as it can observe the cost level in the leader country. Second, there is the public good effect, i.e., the marginal benefit of abatement declines when abatement is a public good and other countries contribute to pollution reductions. Results shows that unilateral abatement would be efficient in reducing uncertainty about the unit costs of abatement if a country with low cost uncertainty would undertake abatement first, while a country with initially high cost uncertainty would follow. However, countries may prefer to act simultaneously because of the larger uncertainties that are inherent in a sequential game.      

300MW循环流化床锅炉NO_x控制分析

本文从300MW循环流化床锅炉燃烧控制和烟气排放现状出发,对300MW循环流化床锅炉NOx排放超标的原因、现状进行深入分析,探讨了控制NOx达标排放的措施,从而为300MW循环流化床锅炉的安全运行、环保达标排放控制提供参考和积累经验。     

浅圆仓环流降氧工艺研究

本文主要对环流充氮工艺进行研究,结果表明：以氮气95%和98%两种浓度比以90%、95%和98%三种浓度进行阶段环流充氮可以节能40%左右;氮气浓度95%保持35天能够抑制锯谷盗、赤拟谷盗和书虱等的生长发育甚至死亡;在密闭保持期间氮气在粮堆中以相似的速度进行自由扩散,而且当仓内氮气浓度大于95%后继续进行补氮成本将大幅增加。     

基于冠层光谱和BP神经网络的水稻叶片氮素浓度估算模型

[目的]快速、准确地诊断水稻叶片氮素营养状况,为水稻氮肥精准管理提供依据。[方法]以江西省农科院8种不同施肥处理的晚稻为研究对象,于主要生育期同步测定了水稻冠层光谱反射率及叶片全氮浓度(Leaf Nitrogen Concentration,LNC),系统分析了原始光谱反射率、一阶微分光谱、"三边"参数以及由350～1 350nm两两波段组合的差值(SD (Rλ1,Rλ2))、比值(SR (Rλ1,Rλ2))及归一化(ND(Rλ1,Rλ2))光谱指数与水稻LNC的相关关系,筛选出敏感参数,并以之为自变量构建了水稻LNC的传统预测模型,另外构建不同指标个数的多元线性与BP神经网络模型,并对模型进行验证。[结果](1)水稻LNC与一阶微分光谱在751nm处的相关性最高(r=0. 822);(2)"三边"参数中的红边面积SDr与LNC的相关性较高(r=0. 687);(3) 750nm附近的红边波段与近红外波段差值组合、550nm附近的绿光波段与近红外波段的比值及归一化差值组合与水稻LNC的相关性较高,以SD (R752,R751)、SR (R534,R1 350)和ND (R534,R1 349)表现最好,相关系数分别为0. 827、-0. 790和0. 788;(4)传统回归模型中以SD(R752,R751)构建的一元线性模型最佳(RC2=0. 665、RV2=0. 750、RMSEV=0. 4%、RPD=2. 034);(5)利用5个指标((R'751、SDr、SD (R752,R751)、SR (R534,R1 350)、ND (R534,R1 349))经逐步回归筛选出的2个指标SD ((R752,R751)和SR (R534,R1 350))构建预测水稻氮素的BP神经网络模型,预测效果最佳,其验证参数值分别为R2=0. 859、RMSEV=0. 302%和RPD=2. 669。[结论]基于单指标构建的传统线性模型计算过程简单但精度略低,而基于2个指标(SD (R752,R751)、SR (R534,R1 350))构建的BP神经网络模型预测精度高于该2指标构建的多元线性模型,表明在指标适合的情况下,BP神经网络对氮素具有较好的预测能力,是一种快速准确估算水稻叶片全氮浓度的方法。     

Reduction in nitrogen fertilizer use results in increased rice yields and improved environmental protection

Overuse of nitrogen fertilizer represents a considerable environmental problem globally, but especially in China. Recently, a recent approach on an experimental scale based on the diffusion of the so-called Three-Control Technology (TCT) successfully alleviated the overuse of nitrogen fertilizer in southern China villages in the Guangdong Province, serving as a reference point for other rice-producing countries tackling similar challenges. Here, we assessed the correlation between rice yields and reduction in the use of nitrogen fertilizer following the introduction of TCT. Our study was based on the collection of primary data from 248 households randomly selected from four rice-growing areas of Guangdong Province, China. Our results show that TCT significantly improved the efficiency in the use of nitrogen. Crucially, participating farmers, including both full adopters and partial adopters, were found to fundamentally change their application practices of nitrogen fertilizer, resulting in major improvements in the local soil and water systems.     

The Environmental Kuznets Curve Hypothesis and Air Pollution in Finland

Abstract

The historiography of mercantilism has been described as a series of disconnected still pictures which reflect the shifting viewpoints of economic thought.¹ However, historians have favoured different concepts of mercantilism not only in response to the shifts of economic science but also because they have held, explicitly or implicitly, different opinions on the problem of how economic ideas are formed and of the role they have played in historical development. The following reexamination of some of those ‘stills’ concentrate on such differences.²     

充氮欠平衡水平井技术

欠平衡压力钻井可大大减轻地层伤害,提高油气井产能,增强油气资源的勘探评价能力,显著地增加钻井速度,提高钻井效益。本文详细介绍了胜利油田黄河钻井三公司在墨西哥进行的欠平横钻井施工过程。