东南沿海地区土地利用转换态势与机制分析

引进土地利用动态度、利用优势度和类型复杂度评判指标,重点揭示20世纪90年代东南沿海地区土地利用类型转换程度、时空差异及其机制。研究表明:东南沿海地区耕地减少122.2×10⁴hm²,建设用地增加85.9×10⁴hm²。土地利用类型转换态势受区域经济社会发展水平及其结构变动的深刻影响。市场经济体制的完善和个体股份机制的创新为沿海土地利用类型快速转换提供了政策平台。人口增长与技术进步是土地利用类型转换的原动力,并通过推进各类产业园区(包括开发区)、中心村镇建设而作用于土地利用类型转换的全过程。     

Health and Welfare in Danish Dairy Cattle in the Transition to Organic Production: Problems, Priorities and Perspectives

During the past few years,organic dairy farming has grown dramatically inDenmark. Consequently, an increasing number ofpeople are encountering this method ofproduction for the first time. Amongst these,many veterinarians have suddenly had to dealwith organic herds in their home district, and,meeting examples of poor animal welfare, theyhave recently started to express some concerns.Against this background, a so-called``Synthesis of Knowledge' project was initiatedto examine the health and welfare of dairycattle and the use of medication in thetransition to organic production. The aim ofthe project was to investigate associatedproblems from the point of view of the dairyherd. Based on qualitative research interviewswith vets and agricultural advisors, as well asfocus group interviews with farmers who hadrecently converted from conventional to organicfarming, an expert panel attempted to identifyproblem areas and possible solutions. Theproblems related to (a) the adjustment to newand unknown practices, (b) poor management ingeneral, and (c) inappropriate legislation fororganic farming.One problem area was the rearing of dairycalves, particularly with regard to theestablishment of post partumrelationships between cow and calf, grouphousing, and the grazing of young animals. A``natural life' was identified as beingfundamental to organic animal husbandry. Interms of animal welfare, this concept can beunderstood as a way of living in which the calfis allowed to express its natural behavior andsatisfy its natural needs. Essentially, theconditions needed for good calf welfare requirethe compatibility and interplay of elementsfrom ``nature' (the natural life; includingopportunities to satisfy natural needs) and``culture' (farmer management skills; exerciseof care). These elements should be balanced toensure animal welfare in organic herds.     

An estimate of the contribution of outdoor concrete yards used by livestock to the UK inventories of ammonia, nitrous oxide and methane

Many farms have unroofed concrete yards used by livestock. These concrete yards have received little attention as sources of gaseous emissions. From 1997 to 1999 measurements were made of emissions of ammonia (NH₃), nitrous oxide (N₂O) and methane (CH₄) from 11 concrete yards used by livestock. A postal survey was carried out to assess the areas of yards on farms in England and Wales to enable the measurements to be scaled up to estimate national emissions. Using the results of this study NH₃-N emissions from farm concrete yards were calculated to be ca. 35×10³ t annually. This is 13% of the current estimated total NH₃-N emission from UK livestock. Concrete yards were an insignificant source of N₂O and CH₄ which were both <0.01% of current estimates of agricultural emissions.     

2种大气SO2监测浓度换算的研究

分别用常规法和碱片法对大气ＳＯ２进行同步监测,并用相关分析讨论了２者之间的相关性,结果表明：２者呈极显著的正相关,相关系数达０．７９４（ｎ＝１１）。它们的关系可以用方程：ｙ＝０．０９０ｘ－０．０３１来表示（其中ｙ为大气ＳＯ２浓度ｍｇ／ｍ＾３,ｘ为硫酸盐化速率ＳＯ３ｍｇ／（１００ｃｍ＾２．ｄ）同时还对方程的适用性进行了分析。     

安徽沿江地区的矿产资源开发与产业结构调整

安徽沿江地区依托矿产资源和长江水运的双重优势，矿业经济发展现已初具规模，城市专业化分工明显，但经济总体水平较低，产业结构层次不高。通过对沿江地区矿产资源开发态势、产业结构的现状分析，得出了本区调整产业结构的必然性，并提出了调整产业结构的主要措施和途径。     

基于DEA方法的农地非农化效率研究

论文运用DEA方法构建了一个农地非农化效率指标,并利用2001-2008 年间省级层面数据,测算得到各省以及4 个地区历年农地非农化效率,结果表明：省域农地非农化效率呈现波动上升、波动下降、保持平稳三种趋势,4 个区域唯有东北老工业基地的农地非农化效率均值高于0.6,全国农地非农化效率均值为0.489,表明8 a 中我国多耗用了51.1%（将近91455.75 hm²）的建设占用耕地的指标。同时,由于初始年份的低效区与高效区在效率变动趋势上存在此消彼长的关系,省域及4 个地区之间农地非农化效率出现趋同的现象。对农地非农化效率影响因素的分析蕴含着“权利二元”的土地制度是过度农地非农化与农地非农化配置结构不合理的症结所在;同时,地方政府财政支出压力又进一步助长了农地非农化的“非理性”;此外,在影响农地非农化效率其他因素中,第三产业比重达到47.02%水平以后,产业结构升级的边际效应才由负变为正;而经济发展水平和城市化率在不同地区的作用方向和强度不同,致使其在全国层面上统计不显著。据此,论文提出应实施“双轮驱动型”土地制度和财税制度改革,以扭转农地非农化效率损失的局面。     

长江流域旱涝灾害特征研究

利用长江流域地区(1956-2007年)148个站点全年的逐日降水资料,采用Z指数作为旱涝指标,对长江流域地区旱涝的转化规律及其时空变化特征进行了探讨,结果表明:长江流域降水量具有明显的年际变化,夏季和年降水量的变化趋势一致;春季的降水周期较夏季具有明显的周期性,从研究的时段内看,春季降水周期为17 ～21年为主,夏季以10～ 15年为主周期;旱涝灾害发生的频率与降水量、暴雨出现的频数呈现正相关,旱涝空间分布上存在一定的结构性,干旱大都发生在长江上游地区(四川和云南的一部分地区)以及湖北部分地区,洪涝主要发生于长江中下游地区,特别是在湖南、安徽、湖北等地.     

穗花狐尾藻对外源15N在水-沉积物界面迁移转化的影响

通过构建室内模拟系统,利用同位素示踪技术研究过量外源NO3-在微环境中的归趋及生长期的穗花狐尾藻(Myriophyllum spicatum L.)在外源氮迁移转化中的作用.结果表明:在穗花狐尾藻组,反硝化作用、微生物固定、沉水植物吸收、异化硝酸盐还原成氨(DNRA)和转化为可溶性有机氮(DON)的去除作用分别占添加15N的47.54%、25.24%、12.76%、0.52%、1.21%;在对照组,反硝化作用、微生物固定、DNRA作用和转化为DON的去除作用分别占添加15N的32.74%、30.79%、0.54%、5.83%.在穗花狐尾藻组和对照组中约87.24%和69.90%的NO3-进行了转化.反硝化作用是去除两处理组中NO3-的主要方式,其次是微生物的固定作用,穗花狐尾藻的直接吸收也对NO3-的去除起到重要作用,DNRA作用和DON对NO3-的去除作用较小.穗花狐尾藻促进了反硝化作用,加快了NO3-在微环境中的迁移转化,直接或间接地促进了微环境对外源NO3-的去除.     

Applicability of the Arrhenius model for ammonia oxidizing bacteria subjected to temperature time gradients

The aim of this work is to identify the range of applicability of Arrhenius type temperature dependence for Ammonia Oxidizing Bacteria (AOB) subjected to temperature time gradients through continuous titrimetric tests. An innovative online differential titrimetric technique was used to continuously monitor the maximum biologic ammonia oxidation rate of the biomass selected in a pilot scale membrane bioreactor, as a function of temperature time gradients. The monitoring technique is based on the measurement of alkalinity and hydrogen peroxide consumption rates in two parallel reactors operated in non-limiting substrate conditions for AOB; both reactors were continuously fed with mixed liquor and in one of them AOB were inhibited with allylthiourea. The effects of temperature decrease rates in the range 1 to 4°C·h⁻¹ were evaluated by controlling the titrimetric reactor in the temperature range 10°C–20°C. The dependence of growth kinetics on temperature time gradients and the range of applicability of Arrhenius model for temperature dependency of AOB growth kinetics were assessed. The Arrhenius model was found to be accurate only with temperature gradients lower than 2°C·h⁻¹. The estimated Arrhenius coefficients (θ) were shown to increase from 1.07 to 1.6 when the temperature decrease rate reached 4°C·h⁻¹.     

含钒烧结矿催化脱除烧结烟气NO_X的性能研究

以含钒烧结矿为催化剂,对烧结烟气进行选择性催化还原(SCR)脱硝,采用X射线荧光光谱仪(XRF)、比表面积与孔隙率测定仪(BET)和X射线衍射仪(XRD)等表征分析含钒烧结矿催化剂的物理化学性质,研究温度、NH3/NO摩尔比、空速、SO_2和H_2O对含钒烧结矿催化剂NO_X转化率的影响,并提出一种新的烧结烟气脱硝工艺。结果表明,含钒烧结矿催化剂的主要活性组分为Fe_2O_3和V_2O_5,在窗口温度为300℃,NH3/NO摩尔比为1,空速为1 000 h-1时,其NO_X转化率可达67%以上;H_2O能促进NO_X的转化,SO_2会降低含钒烧结矿的催化活性,当H_2O和SO_2同时存在时,NO_X转化率明显降低。