大尺度流域不同地貌类型区水土保持减水效益分析

趋势分析结果显示 ,河源涧区、风沙区、丘陵区各代表流域年径流量均在 1970年前后发生一致性改变 ,即从 1970年以来开始有明显的减少趋势 ,平均减流幅度 (与 195 9～ 196 9年径流相比 )以河源涧区 (大理河 )和丘陵区 (小理河 )最大 ,分别为 36 .33%和 36 .2 1% ,风沙区 (海流兔河 )最小 (2 0 .6 1% )。减流幅度的大小是各类型区下垫面状况、水土保持措施和治理程度、降雨量变化等多种因素综合作用的结果。借助适合于黄土高原降雨 -产流特性的月水量平衡改进模型 ,计算天然状态下降雨应有的产流量与同期实测径流量求得减水效果。结果表明 ,3个地貌类型区 70年代的减水效益没有明显差异 ,而在 80年代减水效果差异显著 ,丘陵区 (小理河 ,2 4.99% ) >风沙区 (海流兔河 ,17.2 8% ) >河源涧区 (大理河 ,13.13% )。上述结论为定量评价黄土高原生态环境建设对黄河水资源及水环境演变的影响提供了数据基础。

土壤种子库的研究方法综述

主要从取样方法、取样时间和种类鉴定等方面对土壤种子库研究方法进行综述,重点介绍了种子萌发法,并且提出了要采取长期定位观测的方法对土壤种子库的长期完整动态进行较系统的研究,而且最好在种子库长期的定位研究中搞清楚研究区内植物种的物种特性并且建立一个幼苗标本库,以增加土壤种子库研究的准确性。

沈阳市庭院绿地的结构特征与异质性分析

对沈阳城区庭院绿地的景观结构和格局进行了分析.结果表明,沈阳城市庭院绿地景观斑块以居住区最多,占研究区庭院总数的322%,但绿地面积只占195%.各类庭院占地平均为404hm2,庭院绿地面积平均为093hm2,绿地率为23%.研究区内627%的庭院绿地率在15%以下,绿地率达到30%以上的庭院仅占总数的133%.庭院绿地以微型斑块为主,占庭院总数的70%以上.景观多样性指数以居住区绿地最高,而医院和部队绿地最低.在7个城区中不同庭院绿地类型的优势度差异较大,尤其是于洪区的工厂绿地优势度是和平区的3123倍.各区庭院绿地均匀度指数变化幅度较大,其中居住区绿地的均匀度指数最大,部队绿地最小.居住区绿地斑块破碎化程度最大,部队绿地最小;老城区较新城区破碎化程度严重,其中沈河区破碎化程度最重.

中国地萼苔科新种——云南裂萼苔

描述中国云南产地萼苔科1新种:云南裂萼苔Chiloscyphus yunnanensisC.Gao&Y.H.Wu,本种与Chiloscyphus ciliola(Nees)Gott.相似,但本种植物体紫红色,柔弱,易碎,叶细胞薄壁,三角体不明显等,与其有明显区别。

中国阔叶树干基腐朽两种新病原菌

报道了云南省西双版纳热带雨林地区阔叶树上和四川成都肉桂活树上的两种新的干基腐朽病害,其病原菌为角壳多年卧孔菌(Perenniporia martius(Berk.) Ryvarden)和似雪拟层孔菌(Fomitopsis nivosa(Berk.) Gilb. & Ryvarden)。根据所采集的材料对其进行了详细的形态描述并对病害的症状、分布等进行了讨论。

中国西藏合叶苔属(合叶苔科)一新种——片毛合叶苔

描述了采自中国西藏的苔类植物新种片毛合叶苔ScapaniamacroparaphylliaT .Cao ,C .Gao&J.Sun。新种与腋毛合叶苔S .bolanderiAust.相近 ,区别特征为 :植物体小 ,叶腋内假鳞毛状附属物大 ,呈长片状 ;叶缘齿细胞单列 ,通常 1 - 3个细胞长 ;叶表面角质层粗糙 ,具圆密疣 ,疣大 ,直径达 6- 7μm。

产业竞争力比较研究:以我国东部沿海省市制造业为例

目前,我国产业已由高速发展阶段进入竞争阶段,研究产业竞争力具有非常重要的理论和现实意义。本文分析了产业竞争力的内涵,认为产业竞争力是在一定贸易条件下,产业所具有的开拓市场、占据市场并以此获得比竞争对手更多利润的能力,产业竞争力是衔接国家竞争力和企业竞争力的纽带。比较优势和竞争优势是产业竞争力研究的理论基础,比较优势是竞争优势的基础,竞争优势可以加强比较优势。影响产业竞争力的因素主要包括资源禀赋、区位条件、科学技术、产业组织和政策环境,并对它们进行了简要分析。最后,构建了用区位商综合评价产业竞争力的方法,并用其对东部沿海省市的制造业竞争力进行了评价。

自然灾害风险评估与分级方法论探研:以山西省地震灾害风险为例

自然灾害发生的可能损失一直是灾害风险评估上的难题。本研究以自然灾害风险评估经典模型为基础,提出了新的自然灾害风险评估与风险等级划分方法,利用历史灾情和孕灾环境解决风险评价中致灾因子破坏力与灾害发生的可能,并以山西省地震灾害风险为例进行了定量化评估研究。主要改进在于:确定灾害损失率和环境参数以建立地震灾害可能损失计算模型,计算承灾体地震灾害风险的可能损失量;用标准差和对数位转换的相关计算对地震灾害风险等级进行划分。案例结果显示:山西全省发生地震灾害,可能损失风险包括房屋破坏风险超过3百万间,经济损失风险超过130亿元,人员伤亡风险将近30万人。山西省各县市之间地震灾害综合风险差异明显,最高风险区域是太原市辖区、大同市辖区、晋中市辖区等15个县市区。

镍氢电池复合贮氢合金负极材料的研究进展

根据复合贮氢合金的母体类型即AB5型稀土合金、AB2型Laves相合金、A2B或AB型Mg系合金、V基bcc固溶体型合金和La-Mg-Ni系新型合金,将Ni/MH电池复合贮氢合金负极材料分为相应的5种类型;综述了此类材料的制备方法、微观结构与电化学性能、分析表征方法及机制研究等,提出了目前研究中存在的问题与不足,并对该类材料的研究发展做了展望。

Expression, purification and spectral characterization of p21(Waf1/Cip1)

p21(Waf1/Cip1), best known as a broad-specificity inhibitor of cyclin/cyclin-dependent kinase complexes, can interact with various target proteins, and this ability relies on its structural plasticity. Therefore, studies on the structural properties of p(21) are very important to understand its structure-function relationship. However, detailed studies on its secondary structure and biophysical properties have been comparatively sparse. A human p(21) gene was cloned into the temperature expression vector pBV220 and transformed into Escherichia coli strain JM109.

Mesoporous acid solid as a carrier for metallocene catalyst in ethylene polymerization and a catalyst in catalytic degradation of polyethylene

The possibility of mesoporous acid solid as a carrier for metallocene catalyst in ethylene polymerization and catalyst for polyethylene (PE) catalytic degradation was investigated. Here, HMCM- 41 and AIMCM-41, and mesoporous silicoaluminophosphate molecular sieves (SAPO1 and SAPO2) were synthesized and used as acid solid. Much more gases were produced during catalytic degradation in PE/acid solid mixtures via in situ polymerization than those via physical mixing. The particle size distribution results exhibited that the particle size of SAPO1 in the PE/SAPO1 mixture via in situ polymerization was about 1/14 times of that of the original SAPO1 or SAPO1-supported metallocene catalyst. This work shows a novel technology for chemical recycling of polyolefin.

Partitioning behavior of amino acids in aqueous two-phase systems containing polyethylene glycol and phosphate buffer

The partitioning behavior of four amino acids, cysteine, phenylalanine, methionine, and lysine in 15 aqueous two-phase systems (ATPSs) with different polyethylene glycol (PEG) molecular weights and phosphate buffers has been studied in the present paper. The phase diagrams of the systems are investigated together with the effect of the PEG molecular weight and pH of the phosphate solutions. The composition of these systems and some parameters such as density and refractive index are determined. The influences of salts in ATPSs, side chain structure of the amino acids, pH of ATPSs, and the PEG molecular weight on the distribution ratios of the amino acids have been studied. This work is useful for the purification of amino acids and the separation of some proteins whose main surface exposed amino acid residues are these four amino acids, respectively.

硫堇与寡核苷酸结合序列选择性的光谱研究

用UV-Vis吸收光谱、荧光光谱、圆二色谱以及核磁共振光谱等手段研究了硫堇(TH)与两个不同序列寡核苷酸的作用。TH与寡核苷酸作用后的吸收光谱和荧光光谱产生了明显的减色红移和荧光猝灭效应。分别计算了TH与[oligo d(GC)]2和[oligo d(AT)]2作用的荧光猝灭常数和结合常数,结果表明TH与GC序列的结合能力比与AT序列更强。通过TH与[oligo d(GC)]2作用后双螺旋链构象变化以及TH质子的1HNMR谱峰明显变宽,进一步说明TH与寡核苷酸结合的序列选择性。

Determination of biogenic amines by capillary electrophoresis with pulsed amperometric detection

The biogenic amines, putrescine, cadaverine, spermidine and spermine were separated and quantified by capillary electrophoresis with pulsed amperometric detection. Detection potential of the pulsed amperometric detection was optimized as 0.6 V Optimal separation of the biogenic amines was achieved using a separation buffer of 30 mM citrate at pH 3.5, while keeping the buffer in the detection cell as 20 mM NaOH. Using these conditions, the four biogenic amines were baseline separated. Extrapolated limits of detection for putrescine, cadaverime, spermidine and spermine were 400, 200, 100 and 400 nM for the standard mixture (polyamines dissolved in running buffer), respectively. These are lower than ultraviolet detection and comparable or even lower than laser-induced fluorescence detection results as reported in the literature. The number of theoretical plates was maintained at the 105 level, which is absolutely higher than any reported method. When applying capillary electrophoresis-pulsed amperometric detection to milk analysis, only spermidine was found in amounts varying between 0.1 and 0.5 mg/kg.