对赛罕乌拉自然保护区开展生态旅游的思考

本文在系统科学考察的基础上，对赛罕乌拉自然保护区开展生态旅游提出个人见解，并对当地生态旅游资源进行了评价，对环境旅游进行规划分析，对提高经济效益进行预测。     

加强城市生态环境保护,走可持续发展之路 ——以昆明市为例

生态环境问题是当今许多大城市所面临的最主要问题之一.生态环境本身的多元性及交互作用,决定了生态环境保护的综合性与复杂性.它既涉及到自然科学,又涉及到社会科学;既需要定量的研究,也需要定性的研究;既包括实证的描述,也包括实义的分析和趋势的预测.以昆明为例,重点从城市规划的角度出发,定性地探索城市生态环境保护问题.     

浅谈混凝沉淀在炼油污水中的应用

随着国家对环保的重视，为确保处理效果，混凝沉淀技术在一些炼油污水中得到应用，并取得了较好的效果。     

关于现代模具制造的研究

此文构造了面向工艺过程规划的现代模具制造框架,并与传统模具制造相对比,总结出现代模具制造的主要特点,存在的问题及相应对策。     

北京市公园土壤铜、铅含量及化学形态分布特征

对北京市的12个公园进行表层、深层土壤样品的重金属Cu、Pb含量分析,并对其中10个公园的表层、深层土壤样品进行Cu、Pb的化学形态分析。研究结果表明:北京市部分公园的深层土壤已在某种程度上受到人为扰动,大多数公园表层土壤中存在着一定的Cu、Pb含量积累现象,总体上市区公园比郊区公园明显。公园表层、深层土壤中Cu形态分布的总体规律均为残渣晶格态>有机结合态>铁锰氧化物结合态>碳酸盐结合态>可交换态,表层、深层土壤中Pb形态分布的总体规律均为残渣晶格态>铁锰氧化物结合态>有机结合态>碳酸盐结合态>可交换态,但表层土壤中活性态Cu、Pb的平均比例较深层土壤均有所上升,部分市区公园表层土壤中Cu、Pb的含量较高且活性态比例较大,具有一定的释放潜力和生物有效性。     

Carbon isotope ratios in logged and unlogged boreal forests: Examination of the potential for determining wildlife habitat use

Due to assimilation of recycled CO₂ from litter decomposition and photosynthetic changes in carbon fractionation at low light levels, the foliage at the base of a forest is often more depleted in¹³C compared to that exposed to the atmosphere in either the canopy or in open clearings. This is referred to as the canopy effect. African research has indicated that these habitat differences in foliar ¹³C can be substantial enough to affect the carbon isotope ratios of resident fauna. Previous work documenting a 30-year chronology on moose teeth from Isle Royale National Park indicated a progressive depletion in¹³C and suggested that this could be due to forest regrowth following extensive burning. The present study examined the assumption implicit in this hypothesis that foliar ¹³C varies between open and closed boreal forest sites. I found a marginal canopy effect of 2 ¹³C difference between upper canopy and ground flora for a forest in northwestern Ontario and an average difference of 1.2 in under- and mid-story vegetation between closed forests and open clear-cuts. Because of these small differences, the utility of carbon isotope analysis in quantifying temporally integrated exploitation of deforested habitats will be low for northern boreal locations. In denser forests, such as those in the tropics or western North American where the canopy effect can be expected to be much greater, ¹³C analysis may still offer some promise for determining selection by wildlife of disturbed habitats.     

Synthesis and biodegradation of poly(γ-butyrolactone-co-l-lactide)

Biodegradable polyesters were synthesized by ring-opening copolymerization of -butyrolactone (BL) and its derivatives withl-lactide (LLA). Although tetraphenyl tin was the main catalyst used, other organometallic catalysts were used as well.¹H and¹³C NMR spectra showed that poly(BL-co-LLA)s were statistical and that their number-average molecular weights were as high as 7×10⁴. The maximum BL content obtained from copolymerization BL/LLA was around 17%. TheT _m andT _g values of the copolymers showed a gradual depression with an increase in BL content. NoT _m was obtained for the copolymers containing more than 13 mol% BL. The biodegradability of the copolyesters was evaluated by enzymatic hydrolysis and nonenzymatic hydrolysis tests. The enzymatic hydrolysis was carried out at 37°C for 24 h using lipases fromRhizopus arrhizus andR. delemar. Hydrolyses by both lipases showed that an increase in BL content of the copolymer resulted in enhanced biodegradability. Nonenzymatic accelerated hydrolysis of copolymers at 70°C was found to increase proportionally to their exposure time. The hydrolysis rate of these copolymers was considerably faster than that of PLLA. The higher hydrolyzability was recorded for the BL-rich copolymers. The copolymerization of -methyl--butyrolactone (MBL) or -ethyl--butyrolactone (EBL) with LLA resulted in relatively LA-rich copolymers.     

Enzymatic degradation of poly([R,S] β-hydroxybutyrate)

The synthetic analogue of a bacterially produced polyester, poly(-hydroxybutyrate) (PHB) was synthesized from racemic -butyrolactone using anin situ trimethyl aluminum-water catalyst. The polymer was fractionated into samples differing in molecular weight and isotactic diad content. The latter was closely related to degree of crystallinity. The biodegradation of these fractions were examined by monitoring mass loss over time in the presence of anAlcaligenes faecalis T1 extracellular bacterial poly(-hydroxybutyrate) depolymerase. The fraction with high isotactic diad tacticity content showed little or no degradation over a 50 hour incubation period, whereas the fraction of intermediate isotactic diad content degraded in a continuous steady fashion at a rate that was less than that for bacterial PHB. The low isotactic diad fraction underwent a rapid initial degradation, followed by no further mass loss. The presence of stereoblocks in the polymer structure of the various fractions was an influence on the degree of susceptibility towards degradation and is related to sample crystallinity.     

Residents' preparedness and response to the Kalamazoo Tornado

A survey was conducted of individuals residing directly in the path of the tornado that hit Kalamazoo, Michigan, on 13th May 1980. The residents' tornado preparedness and response were examined in an effort to evaluate the city's emergency warning system. The system was adequate for people on the east side of the city and lacking for west side residents. Other factors pertaining to the storm event and human response were also evaluated.     

MATLAB在环境评价和规划中的应用

本文简述了MATLAB软件的由来和发展，介绍了其主要功能及优点。主要通过在环境评价与规划中的应用实例，展示其在环境科学研究中的应用潜力。文中的第一个实例是MATLAB在多项水质参数的综合评价中的应用，文中对不同的多项水质参数评价方法进行了比较；另一个实例是MATLAB应用于城市固体废物管理规划，极大地提高了规划的水平和准确性，提高了工作效率。最后文中对于该软件在环境学科研究中的应用潜力和优势展开了讨论。