A systems view of integrated coastal management

Natural hazards and human activities in the coastal zone are threatening the integrity of the coastal resource system. Conflicts of interest between short term economic benefits and long term ecologic assets should be identified and solved by means of a balanced CZM approach. Systems analysis, supported by mathematical modelling tools are the appropriate instruments to assist the coastal zone manager. The paper presents a general system description of the coastal zone, and focuses on the modelling of the natural subsystem components of this system as a first step towards a model for Integrated Coastal Management (ICM).

Synthesis and metallophilic properties of troponoid thiocrown ethers

A new class of ionophores with troponoid and thiocrown ether units was prepared. Cation-binding properties of troponoid dithiocrown ethers were characterized using UV and NMR spectroscopies. They have affinity with metal ions; in particular, they showed high affinity with Hg2+. Transport of Hg2+ through a CHCl3 liquid membrane with troponoid dithiocrown ethers was examined in a U-type cell. From an aqueous solution of HgCl2 and CuCl2, Hg2+ is transferred selectively and smoothly, while the Cu2+ remained quantitatively in the original solution. The cavity size of dithiocrown ethers is one of the requirements for effective extraction and transport of Hg2+. However, derivatives with a smaller cavity still extract and transport Hg2+. A polymer-supported troponoid dithiocrown ether was prepared to transport Hg2+ effectively and repeatedly. Comparing the troponoid dithiocrown ether with the benzenoid dithiocrown ether with a similar cavity size, the former was more effective for the transport of Hg2+. It is proposed that the tropone ring assisted the release of Hg2+ from the complex by Coulomb repulsion between the protonated tropone ring and Hg2+.

变水处理与短期遮荫对作物水分利用效率的影响

变水处理与短期遮荫对棉花水分利用效率的影响研究表明 ,在充分供水 -水分胁迫 -复水的变水处理过程中 ,短期遮荫使净光合速率、蒸腾速率、水分利用效率降低 ;光照 -遮荫 -光照期间 ,总的水分利用效率以水分胁迫的最高 ,充分供水的次之 ,复水处理最低 ,其中遮荫 40 %的水分利用效率高于遮荫 75%的处理 .回归分析表明 ,水分利用效率与光合速率表现出极显著正相关 ,两者回归直线的斜率随水分胁迫而增大 ,而水分利用效率与蒸腾速率的关系较弱 ,多数处理两者相关达不到显著水平

黄土塬区旱作冬小麦增产潜力研究

在长期冬小麦潜势试验和肥料试验的基础上 ,建立了作物光温水肥产量模型 ,从光温生产潜力、旱作产量潜势、现阶段施肥水平下光温水肥产量潜力和目前试区产量现状共4个层次 ,对黄土塬区旱作冬小麦的增产潜力进行了分析。结果指出 ,目前黄土塬区冬小麦实际产量仅达到了光温潜力的41 6 %、旱作产量潜势的49 3 %、试区施肥水平下光温水肥产量潜力的78 6 %。因此 ,采用合理施肥方式和加强田间管理 ,黄土高原塬区旱作冬小麦还有较大的增产潜力。

从沙尘暴看黄土的沉积及黄土高原的形成

以近年来我国西北地区多发的沙尘暴现象为缘起 ,对沙尘暴的特征、发生机制等进行了讨论 ;论述了沙尘暴引起的降尘与黄土的堆积和沉积的过程 ;黄土堆积沉积的年龄、颗粒成分等 ;以及沙尘暴与黄土高原的形成之间的关系 ,同时论述了黄土高原的环境变迁 .认为高空均质粉尘的降落是不均匀的 ;高空降尘是突发的 ,而风及流水对堆积粉尘的改造是长期和连续的

用ANUDEM建立水文地貌关系正确DEM的方法研究

针对区域尺度的径流、水土流失定量评价和植被适宜性评价等研究工作需要,利用1∶25万数字地形图和ANUDEM软件,对黄土丘陵区中等分辨率水文地貌关系正确DEM建立方法进行了研究。结果表明该方法所建立的DEM,可以正确反映地貌梁、沟结构及其与流水线网络的关系,对地形描述的能力优于TIN方法建立的DEM;利用ANUDEM和1∶25万地形图插值建立黄土丘陵区DEM的三个主要参数分别为分辨率50或100,计算迭代次数40,第二糙率系数0.8。

森林生态系统中的姣姣者——棘托竹荪研究

该菌系在湖南会同县发现的分解能力和抗逆性很强,是营养及药用价值很高的木腐菌。它在林间栽培可有效地分解采伐剩余物,竹荪的抗污染能力很强,适于林间开放式生产,生产周期短,产量高,营养成份含量高于长裙竹荪及松花粉。

沙质林地土壤阻抗系数测量方法

介绍了土壤阻抗系数的测量目的及测量的一般方法 ;重点描述了应用大地阻抗仪 (YokogawaType 32 4 4 ) (specificearthresistancetester)测量沙质林地土壤阻抗系数的理论背景和室内、外操作步骤与数据处理方法。结果表明 ,使用 32 4 4大地阻抗仪 ,即运用Wenner法测量沙质林地土壤阻抗系数是可行的 ,其测量结果在对土壤分层、确定表层土壤含水量、初步确定地下水位等具有一定的应用前景。

生孢噬纤维粘菌基因文库的构建和纤维素酶基因的克隆

将生孢噬纤维粘菌（ＳｐｏｒｏｃｙｔｏｐｈａｇａＢ２９）染色体用ＰｓｔＩ部分酶切后，连接到大肠杆菌（Ｅ．ｃｏｌｉ）质粒载体ｐＵＣ８上，然后转化Ｅ．ｃｏｌｉＪＭ８３，从而建立了Ｂ２９的基因文库，并筛选一个含有内切葡聚糖纤维素酶（ＣＭＣａｓｅ）的阳性克隆．从此阳性克隆中提取质粒再转化ＪＭ８３，发现所有的氨苄青霉素抗性（Ａｐｒ）转化子都具有ＣＭＣａｓｅ酶活性，证明在大肠杆菌中克隆到一个Ｂ２９的内切葡聚糖酶基因．

试论湿地生态系统的特点

湿地生态系统是一类介于陆地生态系统和水生生态系统之间的过渡类型，是广泛分布于世界各地的一类重要而特殊的生态系统。本文在分析湿地生态系统结构的基础上，着重论述了湿地生态系统的特点，即高生产力，多样性，过渡性，脆弱性和两重性。

植物油增塑聚苯乙烯包膜肥料的研究

目的为了提高化肥的利用率,降低缓释肥料的生产成本.方法以废弃聚苯乙烯泡沫塑料为基本材料、植物油为增塑剂对尿素进行包膜,用乙酸乙酯、乙酸乙酯和甲苯两种体系的溶剂进行溶解,制备包膜肥料.用水中溶出率法和土壤淋溶法研究包膜尿素控释效果.结果表明植物油对聚苯乙烯具有良好的增塑性,采用乙酸乙酯、乙酸乙酯和甲苯两种体系的溶剂进行溶解制备包膜肥料,除A1外,其他5种肥料初期溶出率均低于40%,可以确认用此两种体系溶剂溶解聚苯乙烯皆可行,混合溶剂体系的效果更好些.该包膜肥料的包膜量以10%为最佳.结论利用了聚苯乙烯废弃物,在一定程度上减少了"白色污染",同时又提高了尿素的利用率.综合利用资源、变废为宝、实现可持续性的循环经济发展.

一种基于第二磁盘的解决磁盘碎片的方案

在深入剖析操作系统内部的磁盘碎片产生过程的基础上,提出一种新的解决磁盘碎片方案。首先给计算机新添一个磁盘来保存Windows操作系统中容易产生碎片的目录,然后定期对这个新增磁盘进行碎片整理,从而有效提高操作系统的性能。进而,描述优先地使用固态硬盘作为新增磁盘,将具有更大的优势。经实验证明,这种新增磁盘来解决磁盘碎片问题的方案具有很好的实用价值。

STUDY ON THE SPATIAL PATTERNS OF LAND-USE CHANGE AND ANALYSES OF DRIVING FORCES IN NORTHEASTERN CHINA DURING 1990-2000

Land-use change is an important aspect of global environment change. It is, in a sense, the direct result of human activities influencing our physical environment. Supported by the dynamic serving system of national resources, including both the environment database and GIS technology, this paper analyzed the land-use change in northeastern China in the past ten years (1990 - 2000). It divides northeastern China into five land-use zones based on the dynamic degree (DD) of land-use: woodland/grassland - arable land conversion zone, dry land - paddy field conversion zone, urban expansion zone, interlocked zone of farming and pasturing, and reclamation and abandoned zone. In the past ten years, land-use change of northeastern China can be generalized as follows: increase of cropland area was obvious, paddy field and dry land increased by 74. 9 and 276. 0 thousand ha respectively; urban area expanded rapidly, area of town and rural residence increased by 76. 8 thousand ha; area of forest and grassland decreased sharply with the amount of 1399. 0 and 1521. 3 thousand ha respectively; area of water body and unused land increased by 148. 4 and 513. 9 thousand ha respectively. Besides a comprehensive analysis of the spatial patterns of land use, this paper also discusses the driving forces in each land-use dynamic zones. The study shows that some key biophysical factors affect conspicuously the conversion of different land- use types. In this paper, the relationships between land- use conversion and DEM, accnmlated temperature(>= 10 degrees C) and precipitation were analysed and represented. We conclude that the land- use changes in northeast China resulted from the change of macro social and economic factors and local physical elements. Rapid population growth and management changes, in some sense, can explain the shaping of woodland/grassland - cropland conversion zone. The conversion from dry land to paddy field in the dry land - paddy field conversion zone, apart from the physical elements change promoting the expansion of paddy field, results from two reasons: one is that the implementation of market-economy in China has given farmers the right to decide what they plant and how they plant their crops, the other factor is originated partially from the change of dietary habit with the social and economic development. The conversion from paddy field to dry land is caused primarily by the shortfall of irrigation water, which in turn is caused by poor water allocation managed by local governments. The shaping of the reclamation and abandoned zone is partially due to the lack of environment protection consciousness among pioneer settlers. The reason for the conversion from grassland to cropland is the relatively higher profits of fanning than that of pasturing in the interlocked zone of farming and pasturing. In northeastern China, the rapid expansion of built-up areas results from two factors: the first is its small number of towns; the second comes from the huge potential for expansion of existing towns and cities. It is noticeable that urban expansion in the northeastern China is characterized by gentle topographic relief and low population density. Physiognomy, transportation and economy exert great influences on the urban expansion.