天然沸石对溶液中氨氮吸附特性的研究

为了探讨天然沸石对NH4 的吸附规律,以浙江缙云出产的粒径为2~3.2mm的天然斜发沸石为实验材料,进行吸附等温线实验和吸附动力学实验。结果表明,实验沸石对NH4 的吸附等温线符合Langmuir公式,且对氨氮吸附量的极限值为1.624mol·kg-1;实验沸石对NH4 的吸附反应符合一级动力学方程,反应速率常数为0.1882h-1。通过监测溶液中各阳离子浓度的变化,可确定沸石晶体内与NH4 进行交换的主要离子为Ca2 和Na ,二者占交换总量的96%以上;在交换反应初期,出现了由于沸石晶体中的离子在固液两相中的再分配所造成的离子交换的不等量现象。     

Motivations for the Restoration of Ecosystems

Abstract:  The reasons ecosystems should be restored are numerous, disparate, generally understated, and commonly underappreciated. We offer a typology in which these reasons—or motivations—are ordered among five rationales: technocratic, biotic, heuristic, idealistic, and pragmatic. The technocratic rationale encompasses restoration that is conducted by government agencies or other large organizations to satisfy specific institutional missions and mandates. The biotic rationale for restoration is to recover lost aspects of local biodiversity. The heuristic rationale attempts to elicit or demonstrate ecological principles and biotic expressions. The idealistic rationale consists of personal and cultural expressions of concern or atonement for environmental degradation, reengagement with nature, and/or spiritual fulfillment. The pragmatic rationale seeks to recover or repair ecosystems for their capacity to provide a broad array of natural services and products upon which human economies depend and to counteract extremes in climate caused by ecosystem loss. We propose that technocratic restoration, as currently conceived and practiced, is too narrow in scope and should be broadened to include the pragmatic rationale whose overarching importance is just beginning to be recognized. We suggest that technocratic restoration is too authoritarian, that idealistic restoration is overly restricted by lack of administrative strengths, and that a melding of the two approaches would benefit both. Three recent examples are given of restoration that blends the technocratic, idealistic, and pragmatic rationales and demonstrates the potential for a more unified approach. The biotic and heuristic rationales can be satisfied within the contexts of the other rationales.     

Optimisation algorithms for spatially constrained forest planning

We compared genetic algorithms, simulated annealing and hill climbing algorithms on spatially constrained, integrated forest planning problems. There has been growing interest in algorithms that mimic natural processes, such as genetic algorithms and simulated annealing. These algorithms use random moves to generate new solutions, and employ a probabilistic acceptance/rejection criterion that allows inferior moves within the search space. Algorithms for a genetic algorithm, simulated annealing, and random hill climbing are formulated and tested on a same-sample forest-planning problem where the adjacency rule is strictly enforced. Each method was randomly started 20 times and allowed to run for 10,000 iterations. All three algorithms identified good solutions (within 3% of the highest found), however, simulated annealing consistently produced superior solutions. Simulated annealing and random hill climbing were approximately 10 times faster than the genetic algorithm because only one solution needs to be modified at each iteration. Performance of simulated annealing was essentially independent of the starting point, giving it an important advantage over random hill climbing. The genetic algorithm was not well suited to the strict adjacency problem because considerable computation time was necessary to repair the damage caused during crossover.     

西洞庭湖自然保护区鸟类资源调查

为更好地调查了解西洞庭湖自然保护区的鸟类资源，保护和维持生态平衡，2003—2005年我们对西洞庭湖自然保护区的鸟类资源进行了观察和动态监测，共观察到和鉴定出湿地鸟类217种，隶属于15目58科．本文具体地报道了2003—2005年的鸟类资源调查和动态监测结果，鸟类资源所面临的威胁及其保护措施．     

国外松人工促进天然更新初步研究

国外松飞子成林能力较强，在人工促进措施下进行天然更新，幼树的地径和树高生长速度达到人工造林水平，而每亩可节约造林成本34．95元，经济效益显著。值得大力推广。     

桂西北喀斯特地区6种退耕还林(草)模式的效应

针对桂西北喀斯特地区森林生态系统退化造成的水土流失加剧以及石漠化严重的现状,筛选适合该地区植被快速恢复的5种人工造林(草)方式和自然抛荒恢复模式,分析评价各种模式的生态效应。结果表明,随着经营年限的增加, 6种退耕还林(草)模式都使土壤肥力、生物生产力明显提高。对水土保持最好的是自然抛荒,其次是牧草、板栗 金银花、毛竹和木豆,最差的是任豆;经济效益最好的是牧草,其次是任豆、毛竹、板栗 金银花和木豆,最差是自然抛荒。     

The National Resources Inventory: a long-term multi-resource monitoring programme

Interest in natural resources and the environment has led to the development of new federal monitoring efforts, the expansion of existing federal inventory programmes, and discussions of inter-agency collaboration for natural resource assessment data collection. As federal programmes evolve, knowledge gained from existing long-term survey programmes can provide valuable contributions to statistical and operational aspects of survey efforts. This paper describes the National Resources Inventory (NRI), which has been conducted by the US Department of Agriculture's Natural Resources Conservation Service in cooperation with the Iowa State University Statistical Laboratory for several decades. The current NRI is a longitudinal survey of soil, water, and related environmental resources designed to assess conditions and trends every five years on non-federal US lands. An historical overview is provided highlighting the development of the survey programme. Sample design, data collection, and estimation procedures used in the 1992 NRI are described, and statistical issues related to long-term monitoring are discussed.     

天然水体沉积物的表面特征

本文运用表面络合的模式和原理，研究了江西乐安江下游黄龙庙沉积物的表面特征，通过酸碱滴定实验求定了样吕的零电点ｐＨＰＺＣ、表面质子电荷密度σＨ和表面总吸附位ＮＳ；应用图解法和ＦＩＴＥＱＬ程序计算法求定了江西乐安江下游黄龙库沉积物样品的表面固有常数；对恒定容量模式、扩散层模式和三层模式在天然水体沉积物中的应用进行了比较，研究表明，应用表面络合模式研究天然水体沉积物的表面特是可行的，三种模式都能在一定程     

回顾性环境影响评价及实施程序研究

本文对已在全国和我市卓有成效地开展并已法规化的建设项目环境影响评价制度,提出建设项目竣工投产后的回顾性环境影响评价的建议;对此工作的重要性、实施的可能性和实施程序作了初步研究,以求深化和完善环境影响评价体系,从而促进我国的环境保护事业。     

河西走廊水资源供需平衡及其对农业发展的承载潜力

河西走廊是甘肃省主要经济地区之一,河西走廊未来的经济发展规模在很大程度上取决于本地区水资源的承载能力。本文在水量平衡原理的基础上,对河西走廊水资源的供需平衡和水土资源平衡状况以及水资源对农业发展的承载潜力进行了分析计算,并建立了相应的数学模型,指出了河西走廊水资源的潜力巨大,只有在发展节水型农业和水资源合理、高效利用的条件下才能提高农业用水的承载潜力。