63 resultados para Sanuto, Marino, 1466-1535.


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本文对科尔沁沙地流动沙丘不同坡位(丘间地、过渡带、迎风坡中部、坡顶、背风坡上部和下部)和不同土层深度(0~20、20~40和40~60cm)的土壤线虫群落组成与多样性进行了比较研究。研究结果表明,流动沙丘土壤线虫具有显著的坡位效应,而垂直分布特征不显著。丘间地和背风坡下部具有较高数量和较多种类的土壤线虫,而过渡带和迎风坡中部土壤线虫数量较低、种类也较少。不同坡位土壤线虫总数、食细菌线虫、食真菌线虫和植物寄生线虫数量存在显著差异。除食细菌线虫外,不同土层土壤线虫总数及其各营养类群均无显著差异。土壤含水量和电导率是影响土壤线虫群落空间分布格局的主要因素。土壤线虫群落分布格局的变化反映了流动沙丘土壤微环境的变化,对土壤质量具有一定的指示作用。

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应用生态学是迅猛发展的现代生态学的主体 .寻求解决人口、资源、环境等问题是应用生态学发展的主要动力 .经过 4 0年的发展 ,应用生态学已发展成为一个庞大的学科门类 .应用生态学未来的发展应更多地关注受人类影响和管理的生态系统并将人视为生态系统的组成成分 .应用生态学在当前和今后应给予优先重视的研究领域 ,包括生态系统与生物圈的可持续利用、生态系统服务与生态设计、转基因生物的生态学评价、生物入侵生态学、流行病生态学、生态预报、生态过程及其调控等 .在今后若干年内 ,围绕这些领域 ,可能会出现广泛而活跃的研究热潮以及一些新的特点 .

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建立了一套流动注射石英管原子吸收光谱法测定土壤、植物和药品等样品中微量Hg的方法,研究了酸度、载液和还原液流速及其浓度、氩气流量等条件对测定结果的影响.采用五氧化二钒、硝酸、硫酸进行消解,可获得可靠的分析结果.方法特征量为59 pg,检出限为0.028 μg/L;相对标准偏差为1.60%~3.86%;回收率为94%~102%.

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A method was developed for the determination of micro mercury in the soil, plants and the traditional Chinese medicine using flow injection quartz tube-atomic absorption spectrometry. The effect of the factors such as acidity,. the carrier solution, the flow rate of reductive solution and argon gas, etc. on the determination was studied. When vanadic oxide, nitric acid and sulfuric acid were used to decompose the sample reliable result could be obtained. The characteristic mass of the method is 59 pg, the detection limit is 0.028 mug/L, RSD is < 3.9% and the recovery is in the range of 94% &SIM; 102%.

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The structural relaxation process of an inorganic glass (Li(2)O2SiO(2)) has been studied by differential scanning calorimetry. The sample is subjected to different thermal ageing histories with isothermal stages at an ageing temperature of T-g - 30 degrees C for different ageing times and at an ageing time of 16 h for different ageing temperatures. A four-parameter Tool-Narayanaswamy-Moynihan (TNM) model, is applied to simulate the normalized specific-heat curves measured. The ageing-temperature and ageing-time dependence of the structural relaxation parameters in the TNM model is obtained. (C) 1998 Elsevier Science S.A. All rights reserved.

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The developments of physical aging in phenolphthalein poly(aryl-ether-ketone) (PEK-C) and poly(aryl-ether-sulfone) (PES-C) with time at two aging temperatures up to 20 K below their respective glass transition temperatures (T-g = 495 and 520 K) have been studied using differential scanning calorimetry (DSC). Substantial relaxation within the aging course of several hours were observed by detecting T-g decreasing during physical aging process at the two aging temperatures. The relaxation processes of both polymers are extremely nonlinear and self-retarding. The time dependencies of their enthalpies during the initial stages of annealing were approximately modeled using the Narayanaswamy-Tool model. The structure relaxation parameters obtained from this fitting were used to predict the possibility of physical aging occurring at their respective using temperatures. (C) 1995 John Wiley and Sons, Inc.

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This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Coluber constrictor flaviventris, Coptotermes gestroi, Crotophaga major, Cyprinella lutrensis, Danaus plexippus, Fagus grandifolia, Falco tinnunculus, Fletcherimyia fletcheri, Hydrilla verticillata, Laterallus jamaicensis coturniculus, Leavenworthia alabamica, Marmosops incanus, Miichthys miiuy, Nasua nasua, Noturus exilis, Odontesthes bonariensis, Quadrula fragosa, Pinctada maxima, Pseudaletia separata, Pseudoperonospora cubensis, Podocarpus elatus, Portunus trituberculatus, Rhagoletis cerasi, Rhinella schneideri, Sarracenia alata, Skeletonema marinoi, Sminthurus viridis, Syngnathus abaster, Uroteuthis (Photololigo) chinensis, Verticillium dahliae, Wasmannia auropunctata, and Zygochlamys patagonica. These loci were cross-tested on the following species: Chaetodon baronessa, Falco columbarius, Falco eleonorae, Falco naumanni, Falco peregrinus, Falco subbuteo, Didelphis aurita, Gracilinanus microtarsus, Marmosops paulensis, Monodelphis Americana, Odontesthes hatcheri, Podocarpus grayi, Podocarpus lawrencei, Podocarpus smithii, Portunus pelagicus, Syngnathus acus, Syngnathus typhle,Uroteuthis (Photololigo) edulis, Uroteuthis (Photololigo) duvauceli and Verticillium albo-atrum. This article also documents the addition of nine sequencing primer pairs and sixteen allele specific primers or probes for Oncorhynchus mykiss and Oncorhynchus tshawytscha; these primers and assays were cross-tested in both species.

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We dredged lots of Cenozoic basalts from areas covered from the northern sub-slope to the southern sub- slope of the South China Sea. Based on the study on mineral chemistry of clinopyroxenes in these Cenozoic hasalts, this paper indicates that pyroxenes are mostly enstatite and a few of augite, sahlite and Ca-rich pyroxene. Pyroxene microlite has higher content in, Ca, Ti and Fe than pyroxene phenocryst, it may reflect that the evolution trend of host magma of pyroxene is coincidence with that of alkali rock series. The depth of magma chambers which calculated from equilibrium temperatures and pressures between clinopyroxene and melt are as follows, that of magma of tephrite is about 49km, that of magma of trachybasalt is about 25km, and that of magma of basalt is about 15km. Correspondingly, Equilibrium temperatures( K) of three types rocks mentioned above gradually decrease from 1535 1498 to 1429 to 1369. By using discriminant plot which developed from pyroxene and alkali discriminant diagram of host rock, Cenozoic basalt from the South China Sea belongs to intraplate alkali basalt. The results suggest that alkali basalt series in the study area may be the products of continuous evolution of mantle plume, which result from some physical and chemistry process including partial melting and fractional crystallization of mantle plume during the course of its ascent to the surface.

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本文所研究的区域是西赤道太平洋的两个边缘海盆-苏禄海和南中国海。这两个边缘盆地具有明显不同的水文特征,南中国海底层水冷(<4 ℃)并且通气较好(溶解氧浓度>1.75ml/l),而苏禄海底层水温暖(>10 ℃)并且含氧量低(溶解氧浓度<1.25ml/l)。这些不同的水文特征导致了不同的沉积环境,同时两个海盆的沉积记录也包含了这些水文条件在不同地质时间上如何变化的历史。笔者分别对南中国海的GGC-6孔(12°09'1''E,118°03'9'',水深2775米)和苏禄海的GGC-29孔(8°17'7''E,118°49'9''N,水深1535米)的浮游和底栖有孔虫动物群进行了系统地分析鉴定和统计,并用转换函数对古温度进行了分析,力求通过有孔虫化石群的面貌和定量古生态分析来反映古气候的变化。通过对浮游有孔虫氧同位素环境效应的分析来探索本区的古气候变化。此外还对沉积物中的有机碳和碳酸钙的含量进行了测试和分析。通过上述工作我们得出以下几点认识:1、氧同位素和古水温记录可分末次冰期和全新世两期,由于岩心的长度所限地质记寻年代较短为24000年左右。2、浮游有孔虫G.Grassaformis的最后出现是苏禄海末次冰期极盛时(~18000B.P)重要的地质界线。3、发现在北欧地区短暂寒冷的仙女木期(Younger dryas)在本区也有发现。这在一定程度上说明了仙女木期存在的全球性。4、本区末次冰期与全新世的夏季表层古水温相差不到2 ℃与CLIMAP(1976)赤道太平洋末次冰期以来古水温度的模拟结果相附。冬季表层水温相差较大为3.5 ℃左右。5、瓷质壳底栖有孔虫的繁盛和翼足类的大量保存是苏禄海冰期时底层暖水的良好指示标志。6、本区有机碳的含量反映了底层水含氧浓度的变化。高有机碳代表低氧浓度,低有机碳代表高氧浓度。南中国海一直受到西北太平洋水体的影响,致使其底层水一直处于充氧状态,只是在冰期最盛时稍有降低。而苏禄海底层水氧浓度较低,尤其是末次冰期极盛时隔绝状态加强,大量的降水使表层海水淡化分层,致使底层水缺氧状态加剧。7、本区做为西赤道太平洋的边缘海,其CaCO_3旋回模式却与太平洋相反,而与大西洋一致,即冰期碳酸钙含量低,全新世冰后期碳酸钙含量高。冰期陆源物质供应的加强和全新世浮游有孔虫生产力的提高是控制本区碳酸钙旋回的主要因素。此外,冰期海水溶解作用的加强是南中国海冰期低CaCO_3含量的另一个重要原因,而苏禄海的碳酸钙沉积受海水溶解作用的影响却很小。8、浮游有孔虫N.dutertrei的大量增加和相对较轻的δ~(18)O值说明冰期最盛时海水表面的盐度较低。末次冰期时东南亚地区东北季风加强西南季风减弱,由于特殊的地理环境使本区在冰期时降水大量增加。

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南海是西太平洋最大的边缘海之一,位于欧亚板块、印-澳板块以及太平洋板块之间。南海海底扩张停止(15.5Ma, Briais et al., 1993) 后的板内火山作用,影响着中国南部、中南半岛、大洋基底和分裂的微大陆片段的广大地区。对南海新生代玄武岩进行地球化学研究,不仅对于理解南海板内火山作用的深部地幔过程有着重要意义,而且对南海形成演化及含油气盆地形成的深部动力学机制有着深远意义。 南海新生代玄武岩K-Ar/Ar-Ar年龄为3.8-7.9Ma, 表明为晚中新世以来的岩浆活动产物,与周边地区的碱性火山岩在年龄上的一致性。岩石学特征表明,南海新生代玄武岩的矿物组合为橄榄石、单斜辉石、斜长石,与特征的碱性玄武岩的矿物组合一致。由橄榄石所计算的南海底潜在地幔温度(Tp)平均值为1661℃, 暗示南海地区下的地幔可能存在热量异常,为海南地区存在地幔柱的观点提供了证据。单斜辉石富钙、钛,由单斜辉石-熔体平衡温压计计算的岩浆房深度分别为:碱玄岩岩浆房深度约49km(对应压力为1.46~1.48 GPa);粗面玄武岩岩浆房约25km(对应压力为0.76 GPa);玄武岩岩浆房约15km(对应压力为0.44GPa)。由碱玄岩→粗面玄武岩→玄武岩,平衡温度(K)依次降低:从1535~1498→1429→1369。由斜长石微晶所计算的岩浆喷出地表的温度为989℃。 主量元素特征表明,岩石类型主要为碱玄岩,有少量的粗面玄武岩和玄武岩,属于碱性系列。微量元素方面,大离子亲石元素(LILE)以及高场强元素(HFSE)特别是Nb、Ta、Ti、Y等元素均呈现富集现象,Yb、Sc、Sr以及K、U、Th等生热元素相对亏损,微量元素及稀土元素分布岩石类似板内OIB微量元素的全球平均值。同位素地球化学研究表明,源区存在两个混合端员并具Dupal Pb异常:一个为DMM,位于软流圈或岩石圈地幔中;另一个为EM2源区,可能来自位于核-幔边界处的海南地幔柱而非大陆底岩石圈地幔。研究表明,南半球Dupal异常不存在全球范围内的地区专属性,本区存在的Dupal异常与南半球Dupal异常可能不存在联系。在南海新生代玄武岩的成因过程中,海南地幔柱在为岩石圈地幔的部分熔融作用提供所需的热量同时,也在物质上作出了贡献。南海盆新生代碱性玄武岩由不同程度的部分熔融作用,以及岩浆在上升期间或者在高位岩浆房中的橄榄石等矿物分离结晶作用所形成,同时还可能发生了堆晶作用。构造环境判别表明,玄武岩浆在上升到地表过程中几乎未受到地壳混染。 南海新生代玄武岩的地球化学研究表明,在玄武质岩浆的深部地幔演化过程中,海南地幔柱可能起着重要的作用。通过引入海南岛地幔柱这个概念,本文建立了一个新的有关南海形成演化的初步的概念性模型:(1)50-32Ma,印度洋板块-欧亚板块碰撞及其所导致的太平洋板块后退的综合效应为南海地区提供了一个伸展环境,此伸展环境为地幔柱物质的上升提供了通道;(2)32-21Ma,当地幔柱柱头到达软流圈时, 通过侧向物质流开始同扩张中心发生相互作用,促进了南海的扩张,并在26-24Ma期间发生了洋脊重新就位事件,使扩张中心从原来的18°N附近(即现今西北海盆的中心)调整到15.5°N附近(即现今的东部亚盆);(3)21-15.5Ma, 随着地幔柱效应的逐渐增强,热点-洋脊相互作用越来越强烈,在大约21Ma发生了洋脊的再次重新就位事件,诱发了西南海盆的扩张;(4)15.5-现在,由于印澳板块前缘与巽他大陆碰撞,使得南海大约在15.5Ma停止扩张,并沿着南沙海槽及吕宋海沟向菲律宾岛弧及巴拉望地块之下俯冲,而南海热点继续活动,在地表处直到第四纪还有碱性玄武岩喷出。

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本文首先根据甜菜碱及其类似物(季胺化合物)特殊的化学性质,选择了离子交换层析法对海藻中的季胺化合物进行了分离和提取。用德尔根多夫显色剂验证了海藻中德尔根多夫阳性化合物的存在,分离产物与雷氏盐形成沉淀证明了这些化合物季胺基团的存在。为了排除用离子交换层析法分离得到的样品溶液中其它化合物的干扰,本文采用了与季胺基团有高度化学反应特异性的雷氏盐将季胺化合物从样品溶液中特异沉淀出来,然后将沉淀转化为可溶性的硝酸盐溶液,用氢氧化钠标准溶液滴定而得到海藻中甜菜碱的总毫摩尔数。将滴定完的溶液和未滴定的溶液一起浓缩后经过离子交换层析并洗脱后使季胺化合物再生,再次用雷氏盐将其沉淀 出来并转化成溶液,用氢氧化钠标准溶液滴定出甜菜碱的总毫摩尔数,与第一次的结果比较,说明此方法是一种误差较小、重复性好、简便可取的方法。本研究共对七种典型的红藻、褐藻和绿藻的甜菜碱的总含量进行了测定,甜菜碱的灯似物也在分离行到的产物中,但它们的含量没有测,定结果表明,红藻和绿藻中菜碱的含量较高,浒苔中甜菜碱的干重百分比甚至能高达0.86%;褐藻中甜菜碱的含量相对要低一到两个数量级。本研究还隶属海藻化学研究室九五攻关课题一“海藻中的植物生长调节剂”的一部分,这些测定结果对海藻资源中甜菜碱及其类似物的开发和利用有很高的参考价值。本文还着重分析了海藻中甜菜碱及其类似物的功能,并对其潜在的应用前景进行了展望。该研究内容填补了国内的空白。

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本发明涉及一种大黄植物的引种栽培方法,该方法包括种子处理技术、人工育苗技术和引种栽培技术;本发明通过对种子进行物理和化学处理方法,使高原野生植物种子的萌发率达90%以上;通过人工育苗途径,可根据种苗数量和季节需要,有效地提供优质种苗;通过在一定海拔的适宜旱耕地或适宜荒地直播和移栽的途径,可快速恢复高原野生植物的资源量,并有效地保证了高原野生植物的药材品质和药效成分。

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