昆明地区花卉害虫及天敌

1997 年5～ 8 月至1998 年4～ 8 月, 对昆明地区的花卉害虫及天敌进行了考 察和标本采集, 共采到花卉害虫及天敌标本4500 多号, 经鉴定分14 目, 65 科, 158 属, 205 种。标本保存在中国科学院昆明动物研究所。

科学交叉——变离散为整体的混凝剂

跨学科综合研究是科学发展的必然和现实的需要，是联系不同学科和研究主体的纽带，也是变离散为整体的混凝剂。中国科学院应主动迎接时代的挑战，在宏观决策与管理上为科学交叉的发展推波助澜

RESPONSES OF Elodea nuttallii AND Ceratophyllum demersum TO HIGH TEMPERATURE

There were large losses of exotic species Elodea nuttallii during summer in eutrophic lakes of the middle and lower reaches of the Yanatze River, China. To investigate the main causes, the heat tolerance of E. nuttallii was studied and compared with that of native species Ceratopkyllum demersum by using an aquaria system in the laboratory. Under 4500 lx light intensity and 12-h L/12-h D cycle, E. nuttallii cultured in 1/5 Hoaglands solution at 39 degrees C showed a positive growth rate during the first 15 days, and the growth rate was higher than that at 35 degrees C. But after 15 days, the growth rates became negative for those cultured both at 39 and 35 degrees C. However, the growth rate was positive for more than 20 days for those cultured at 25 degrees C. Under the same conditions, the growth rate, productivity and chlorophyll content of E. nuttallii were significantly higher than that of C. demersum. Heat tolerance of E. nuttallii was also stronger than that of C. demersum. The optimal temperature for the growth of the two plants depended on the experimental period: both plants grew at an optimal rate at higher temperature if the experimental period was short; nevertheless the plants achieved optimal growth at a lower temperature if the experiment was conducted for a longer period. At the same light intensity, the heat tolerance of C. demersum in tap water with sediment was markedly stronger than that of E. nuttallii at 39 degrees C. Average growth rate of C. demersum was 4.5 times higher than that of E. nuttallii within 25 days. The positive growth period lasted for less than 25 days for E. nuttallii and for more than 25 days for C. demersum. When they were cultured in 1/5 Hoaglands solution and in tap water with sediment, the growth rate of C. demersum increased from 0.4 to 79.4 mg/d.g fresh weight (FW) within 20 days. E. nuttallii increased from 8.3 to 24.4 mg/d-g FW within 20 days. Both grew better in tap water with sediment than in 1/5 Hoaglands solution. The results demonstrated that the nutritional status of the water other than the high temperature affected the heat tolerance of E. nuttallii during summer. E. nuttallii has great ecological safe risk in China.

太阳能空气饱和蒸馏器的试验研究

研究得到了太阳能空气饱和蒸馏器在稳态情况下和不同海水加热温度下的蒸发速度实验式:lgD=7.062+3.446t_0海水加热温度是影响淡水产量的主要因素，以46.2℃为转折，超过此温度，蒸发速度急促增加。液-气两相重量流量比(W/G)，必须与海水加热温度相适应。温度较高，(W/G)值也应较大，这样才能最大限度地提高产水量和降低产水的耗热量。当t_0=96℃时，(W/G)_(最佳)=12;当(W/G)=11时，t_(0最佳)=90℃。在一般太阳辐射条件下，t_0=60℃，(W/G)=1.67—3.0时，热耗值最低。过多地通入空气是空气饱和蒸馏器动力消耗较大的重要原因。在适当工况下进行操作，所需空气量较小。这样，不但产水量高、热耗值低、系统阻力减少，而且能耗大幅度降低。 模拟试验表明:太阳能空气饱和蒸馏器在太阳辐射日总量4500〔千卡/米~2〕时，每平方米集热器面积，每日可产淡水5—7公斤，所需翅片冷凝器换热面积为0.21〔米~2/时·公斤淡水〕。

低温制备微晶硅薄膜生长机制的研究

采用热丝化学气相沉积技术制备了一系列处于不同生长阶段的薄膜样品,用原子力显微镜系统地研究生长在单晶硅衬底和玻璃衬底上薄膜表面形貌的演化.按照分形理论分析得到:在玻璃衬底上的硅薄膜以零扩散随机生长模式生长;而在单晶硅衬底上,薄膜早期以有限扩散生长模式生长,当膜厚超过某一临界厚度时转变为零扩散随机生长模式.岛面密度与膜厚的依赖关系表明,在临界厚度时硅衬底和玻璃衬底上的岛面密度均出现了极大值.Raman谱的测量证实,玻璃衬底上薄膜临界厚度与非晶/微晶相变之间存在密切的关系.不同的衬底材料直接影响反应基元的表面扩散能力,从而造成薄膜早期生长模式的差异.

长白山二道白河溪流大木质物残体的初步研究(英文)

主要对长白山北坡溪流大木质物残体现存量进行了调查和研究,包括两段河道内所有大木质物残体的基径、顶径、长度、腐烂级,并在其中一段对树种尽可能进行了鉴别,以分析河岸带植被与溪流大木质物残体的关系。在调查的红松阔叶林植被带内4500 m长河道内,共发现溪流倒木425株,分属于17个树种;其中III、IV级腐烂占相当大的比重,与林地倒木II、III级腐烂占优有所不同,其原因可能与分解环境的不同有关。两段河道溪流大木质物残体的现存量为1.733 m3/100m、 10.83m3/hm2和1.709 m3/100m、 21.36 m3/hm2。处于III、IV级腐烂的溪流大木质物残体所占比重较大,与在森林中情况有所差异,可能与分解环境的不同有关。溪流大木质物残体和林地活立木的个体数量的径级分布基本上为反J型,而它们材积的径级分布均为典型的J型。溪流大木质物残体的树种组成和不同树种的材积与河岸带植被密切相关,但存在差异,分析这种差异可以深入了解河岸带植被动态。图1表4参18。

黄土高原不同密度刺槐(Robinia pseudoacia)林地水分生产力与土壤干燥化效应模拟

应用WinEPIC模型模拟研究了1957~2001年期间黄土高原半湿润区长武和半干旱区延安不同密度刺槐(Robinia pseudoacia)林地水分生产力演变规律和深层土壤干燥化效应。结果:(1)长武和延安高密度(6000株/hm2)、中高密度(4500株/hm2)、中低密度(3000株/hm2)和低密度(1500株/hm2)等4种处理刺槐林地逐年生物量模拟值均呈现快速增加、达到最大值后又逐年波动性降低的变化趋势,林地密度越高早期逐年生物量越高,后期逐年生物量差异缩小,两地均以低密度处理逐年生物量平均值和累积生物量模拟值最高;(2)4种密度处理45年生刺槐林地年均耗水量值基本相等,长武和延安分别为603mm和566mm,但生长前期年耗水量明显高于后期,并高于同期年降水量,林地密度越高前期耗水量越高,中期以后各密度处理耗水量基本接近且波动趋势基本一致,林地密度越高干旱胁迫程度越重;(3)模拟生长初期,4种密度处理刺槐林地0~10m土层逐月土壤有效含水量均呈现强烈的波动性降低趋势,长武各密度处理刺槐林地分别在7~23年生、延安分别在7~17年生之后逐月土壤有效含水量均在0~200mm较低水平上随降水量变化而波动..

模拟酸雨条件下树木氨基酸变化与害虫的发生关系

本文通过人工模拟酸雨试验小区置木招引的研究方法,对马尾松次期性害虫进行了招引试验,并对样木中16种氨基酸含量进行了分析。结果表明,马尾松样木在人工模拟酸雨条件下比对照都易招次期性害虫的入侵,样木中氨基酸含量也比对照高。但在强酸(pH=2)条件下其氨基酸含量比对照低,其原因还有待进一步探讨。

甜高粱的适生区及能源资源潜力研究

运用中国资源环境数据库中的1kmDEM数据、1:100万中国土地利用数据、省区面元数据和中国自然地图数据库中的年降水量、活动积温和土壤pH值数据,在研究现有甜高粱生长的限制性环境因子的基础上,确定了甜高粱生长发育的环境因子及其阈限值,形成了年降水量≥400mm、活动积温2500～4500℃、土壤pH值6.0～8.5、坡度≤15°甜高粱在某地区能够生长发育的4个阈限指标;假定甜高粱种植不占用耕地、林地和草地,不占用沼泽地等生态用地,基于GIS空间分析功能,计算出甜高粱适宜种植的边际性土地资源的空间分布、类型

近30年来长江源头高寒草地生态系统退化的遥感分析:以青海省治多县为例

为了对长江源头高寒草地退化的时空过程规律取得全面客观的科学认识,本文利用20世纪70年代末、90年代初和2004年的陆地卫星遥感影像为信息源,结合气象数据、DEM、草地分布图及社会统计数据等辅助资料,以青海省治多县为例分析了近30年来长江源头的高寒草地生态系统退化的时空格局与过程及其驱动因素,从新的视角阐释高寒草地退化的过程与机理,为退化高寒草地的恢复、治理与区域可持续发展提供了科学依据。结果表明,研究区高寒草地生态系统的退化呈现自东南向西北,退化面积减少、退化程度降低、退化类型由复合型向单一型过渡的总体趋势。研究区东部是草地退化最严重的区域,主要表现为沿着原退化草地斑块的扩张,而西部即唐古拉山以北的广大地区由于下垫面起伏较低则以草地覆盖度的轻度下降退化为主。草地退化时间过程特征的总体趋势是持续退化、后期加剧,前后两个时段对比可以看出草地退化比重和程度皆呈逐渐加剧的趋势,退化面积比重净增9.86%。地形因素的影响分析亦发现,研究区高寒草地退化主要发生在海拔4500～4900m、坡度5～15°范围内的阴坡。研究区草地退化格局在20世纪70年代以前就已经形成,气候变化对高寒草地退化的影响是长期、缓慢的,而研究区人口和家畜数量变化的分析可以得出人类活动特别是过度放牧是草地退化发生的最重要诱因。

Spatio-temporal changes in annual accumulated temperature in China and the effects on cropping systems, 1980s to 2000

Change in thermal conditions can substantially affect crop growth, cropping systems, agricultural production and land use. In the present study, we used annual accumulated temperatures > 10 degrees C (AAT10) as an indicator to investigate the spatio-temporal changes in thermal conditions across China from the late 1980s to 2000, with a spatial resolution of 1 x 1 km. We also investigated the effects of the spatio-temporal changes on cultivated land use and cropping systems. We found that AAT10 has increased on a national scale since the late 1980s, Particularly, 3.16 x 10(5) km(2) of land moved from the spring wheat zone (AAT10: 1600 to 3400 degrees C) to the winter wheat zone (AAT10: 3400 to 4500 degrees C). Changes in thermal conditions had large influences on cultivated land area and cropping systems. The areas of cultivated land have increased in regions with increasing AAT10, and the cropping rotation index has increased since the late 1980s. Single cropping was replaced by 3 crops in 2 years in many regions, and areas of winter wheat cultivation were shifted northward in some areas, such as in the eastern Inner Mongolia Autonomous Region and in western Liaoning and Jilin Provinces.

Investigation on preparation and fluorescence properties of oxy-fluoride glass co-doped with Er3+ and Yb3+

The glass sample based on the composition of 45PbF(2)-45GeO(2)-10WO(3) co-doped with Yb3+/Er3+ was prepared by the fusion method in two steps: melted at 950 degreesC for 20 similar to 25 min then annealed at 380 degreesC for 4 h. Through the V-prism it is found that the refractive index of host glass and the sample are 1.517 and 1.65 respectively. The transmittance was observed by using the ultraviolet-visible-infrared spectrometer in the wavelength range from 0.35 to 2.5mum. The transmittaitce of the host glass is beyond 73%. That of the sample is beyond 50% and there are characteristic absorption peaks of rare-earth ions. The emission spectrum was measured by using the Hitachi F-4500 fluorescent spectrometer pumped by 980 nm semiconductor laser. There are a strong emission peak at 530 nm and a weak peak at 650 nm.

BaLiF_3∶Ce~(3+)纳米粒子的制备及其光谱特性

BaLiF3属立方钙钛矿型复合氟化物,作为高效闪烁晶体可用于热中子检测[1].由于其能带隙宽,易于实现各种不同价态稀土离子掺杂,可以获得许多可调谐性质,因此它也是比较理想的光学功能材料的基质[2].Ce3+激活的BaLiF3晶体作为紫外发射的短波固体激光材料和光放大材料的研究多有报道[3~5].Ce3+的发射特性强烈依赖于基质晶体结构[6,7].氟化物基质中氧杂质的含量是影响光谱性质的重要因素[8].为了寻找氧含量低、发射波长更短、可调谐范围更宽的激光材料,本工作制备了BaLiF3∶Ce3+纳米晶,获得了一些新的有意义的实验结果.如果将其引入合适的聚合物基体制备出纳米复合体系,有可能为新一代杂化激光材料提供更理想的光学活性组分[9].1实验部分1.1仪器用日本R igaκu D/maxⅡB型X射线衍射仪(XRD)测量样品的晶体结构,辐射源CuKα1(λ=0·154 1 nm);用日本H itachi S-570环境扫描电子显微镜(ESEM)观察样品的形貌和粒径大小;用日立F-4500荧光光谱仪测试样品的激发和发射光谱;用英国VG公司ESCALAB MKⅡX射线电子能谱仪(XPS)检测样品的含氧量.1.2实验过...