957 resultados para 37.048.2
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采用层次分析法和综合指标法对辽宁省生态系统服务重要性进行了定量评价,分析了辽宁省生态系统生物多样性保护、水源涵养、土壤保持、沙漠化控制和营养物质保持重要性及其空间分布特征,在此基础上进行了辽宁省生态系统服务重要性及其区域分异规律的综合评价。结果表明:辽宁省生态系统服务均处于比较重要以上;其中极重要地区比重最大,占全省国土面积的60.66%;中等重要地区比较多,占全省国土面积的37.01%;其它少数地区为比较重要地区,占全省国土面积的2.33%。
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由于土壤理化性质的复杂性和真菌细胞壁结构的特殊性,从土壤样品中提取真菌基因组DNA比较困难。中国北方土壤与其它地区土壤相比有其自身的特点,因此,有必要优化一种适合于北方土壤真菌DNA提取的方法。本实验向灭菌黑土中分别投加12种在系统分类上差别较大的真菌,以传统土壤总DNA提取方法及纯菌DNA提取方法为基础,分别与蜗牛酶,纤维素酶进行组合、优化,得到7种不同的土壤真菌基因组DNA提取方法。利用真菌28SrDNA通用引物U1/U2-GCPCR-DGGE分析方法分别考察了7种不同方法所提取土壤真菌基因组DNA的多样性和代表性。结果表明:1)液氮研磨,纤维素酶、蜗牛酶和溶菌酶(浓度分别为6、3和1mg.ml-1)37℃作用60min,2%SDS于65℃裂解30min;2)-65℃~65℃冻融3次,纤维素酶、蜗牛酶和溶菌酶(浓度分别为6、3和1mg.ml-1)37℃作用180min,2%SDS于65℃裂解30min的组合具有较好的提取效果。利用后一种方法分别对3种理化性质差异较大的中国北方自然土壤样品真菌DNA进行提取并分析,表明所提取土壤基因组DNA真菌特异性PCR-DGGE图谱条带丰富,该方法可用于多种北方土壤真菌多样性研究。
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报道了新疆三工河流域的苔藓植物 ,计 37科 91属 2 16种 (变种、变型 ) ,包括 1新疆新记录属和 1新疆新记录种。其中科数约占新疆天山总科数的 75 % ,属数约占 6 5 % ,种数约占 6 0 %。并分析了该流域苔藓植物的分布特征。研究表明 :该流域苔藓植物可分为树生、石生、石面薄土生、腐木生、水生和土生苔藓植物群落。其中 ,土生种类种数最多 ,约占该流域苔藓植物总数的 44 %。其次为石面薄土生的种类 ,约占该流域苔藓植物总数的 31%。不同的植被带又具有其独特的苔藓植物种类组成和分布特点
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(C5H9C5H4)(3)NdBrLi(THF)(4)(1)(C5H9=cyclopentyl) was obtained from the reaction of NdCl3 with C5H9C5H4Na and LiBr (Nd:Na:Li=1:2:1 molar ratio) in THE X-ray crystallography showed that the ten-coordinated neodymium atom is bonded to three cyclopentylcyclopentadienyl(eta(5)) rings and a single bromine atom bridging a lithium which is bonded to three THF molecules. Complex 1 is triclinic, P1 space group with unit dimensions of a= 12.048(2), b= 13.498(3), c= 13.831(3)Angstrom, a = 104.16(3), beta = 104.07(3), gamma =95.96(3)degrees, V=2083.3(7)Angstrom(3), Z=2, D-c=1.35Mg/m(3) and F(000)=874. (C5H9C5H4)(3)SmTHF (2) was synthesized by reaction of anhydrous SmCl3 with C5H9C5H4Na at a molar ratio of 1:3. The structure was determined by X-ray crystallography. The ten-coordinated samarium atom is bonded to three cycloperrtylcyclopentadienyl rings and one oxygen of THF molecule to form a pseudo-tetrahedron. Complex 2 is orthorhombic, Fdd2 space group with unit cell dimensions of a =28.175(5)Angstrom, b =46.24(2) Angstrom, c =9.167(4) Angstrom(3), V=11943(8)Angstrom(3), Z= 16, D-c = 1.38Mg/m(3) and F(000)=5136.
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无水三氯化钕与环戊烷基环戊二烯钠、溴化锂(1:2:1摩尔比)反应,除去不溶物和溶剂后,产物在己烷/四氢呋喃溶剂中冷冻得到兰紫色晶体(C5H9C5H4)3NdBrLi(THF)3(配合物1)。其中心金属Nd3+的配位数为10,以η5与3个环戊二烯基相连,并通过单溴原子桥连锂原子,形成双核结构。该晶体属三斜晶系,P`1空间群。晶体学参数为a=12.048(2)、b=13.498(3)、c=13.831(3);α=104.16(3)、β=104.07(3)、γ=95.96(3); V=2083.3(7)3、Z=2、Dc=1.35Mg/m3、Mr=847.01gmol-1、F(000)=874。无水三氯化钐与环戊烷基环戊二烯钠(1:3)反应,产物在-30oC下的己烷溶剂中结晶得桔红色晶体(C5H9C5H4)3SmTHF(配合物2)。该晶体属正交晶系,Fdd2空间群。晶胞参数a=28.175(5) 、b=46.24(2)、c=9.167(4);V=11943(8)3、Z=16、Dc=1.38Mg/m3、 Mr=622.11 g·mol-1、F(000)=5136。10配位的金属Sm3+与3个环戊二烯基以η5相连,并结合...
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The redox process of norepinephrine in pH = 7.0 phosphate buffer solution at glassy carbon electrode was studied by circular dichroism spectroelectrochemistry with a long optical path thin layer cell. The spectroelectrochemical data were analyzed with the double logarithm method. According to the double logarithsmic plot results, the mechanism of electrochemical oxidation of norepinephrine is an irreversible process with a subsequent chemical reaction (EC) to form a norepinephrinechrome. Both of norepinephrinequinone and norepinephrinechrome are followed E mechanisms. Some kinetic parameters about the electrochemical process, i.e. the electron transfer coefficient and number of electron transfered, alpha n = 0.38, the formal potential, E-1(0)' = 0.20 V, the standard heterogenous electron transfer rate constant, k(1)(0) = 1.2 x 10(-4) cm s(-1) for the oxidation of norepinephrine, alpha n = 0.37, E-2(0)' = 0.25 V and k(2)(0) = 4.4 x 10(-5) cm . s(-1) for the reduction of norepinephrinequnone and alpha n = 0.33, E-3(0)' = -0.25V and k(3)(0) = 1.1 x 10(-4) cm . s(-1) for the reduction of norpinephrinechrome, were also estimated.
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Six new compounds, alpha,beta-KaHb[GeW(9)M(3)(H2O)(3)O-37]. xH(2)O(M = Al, Ga, In; a + b = 7) and alpha-K9H5[Ge2W18Ga6(H2O)(3)O-74]. 20H(2)O, were synthesized from the lacunary precursors a and beta-GeW9O3410- and characterized by elemental analysis, spectroscopy and electrochemistry. Tungsten-183 NMR spectra of the title complexes consist of two lines with intensity ratio 2:1 as expected for trisubstituted heteropoly anions. The intensity ratio of alpha-Ga compound is 1:2, which is different from others(a:1). With the help of FAB mass spectrum, we concluded that it is a dimer with D-3h structure in aqueous, and the others exist by monomers with C-3v structures.
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调查青藏高原高寒草甸生态系统中两种主要啮齿动物及其天敌动物的种群密度,分析天敌动物对两种啮齿类的捕食方式、捕食强度,探讨啮齿类动物的捕食风险及生存对策。研究结果表明,高原鼠兔和高原鼢鼠的种群密度分别为4.97只/hm~2和10.6只/hm~2,而它们的主要天敌赤狐、艾虎和香鼬的种群密度分别为0.16只/100hm~2、0.37只/100hm~2、3只/100hm~2。艾虎和香鼬在取食过程中主要搜寻啮齿类的洞道系统,全部食物几乎都来源于洞道系统内;赤狐或取食地面活动的鼠兔,或挖掘洞口待高原鼢鼠封闭洞口时取食猎物。高原鼠兔在赤狐、艾虎和香鼬的食物中所出现的频次分别为100%、96.1%、100%,高原鼢鼠在3种天敌动物的食物中所出现的频次分别为87.5%、73.2%、0%。3种天敌动物对高原鼠兔和高原鼢鼠的捕食强度分别为0.703%和0.038%,高原鼠兔和高原鼢鼠所承受的捕食风险分别为0.780和0.393。高原鼠兔在高的捕食风险下通过行为对策和繁殖对策增加其适合度,而承受捕食风险较小的高原鼢鼠主要通过封闭的洞道系统和高的存活率增加其适合度。
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茶卡-共和盆地及其毗邻地区位于青海省的东部,约处于北纬34°45'~37°00',东经98°45'~101°30'.海拔2 800~5 305 m,面积约38 300 km2,属于高原大陆性气候类型.本区共有野生种子植物59科、277属、854种.分别占青海省总科数的65.56%、总属数的54.53%、总种数的37.37%.区系特征如下:1、种类相对较贫乏,木本更贫乏.2、就属的层面而言,本区属于以北温带成分,特别是欧亚大陆温、寒地带典型成分为优势的,兼具旱生温性、耐寒温性和高寒类型的温带区系性质.3、许多种、属和热带类型均以本区为边缘分布区,因而区系的边缘性质明显.4、为青藏高原高寒区系、黄土高原温性(草原)植物区系和亚洲东部荒漠区系在我国的交汇过渡区,区系的过渡性质明显.5、是青藏高原植物亚区唐古特地区的一部分.6、是青海植物区系或"唐古特植物地区"划分植物亚地区的关键区域.
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对青海省青海湖国家级自然保护区内鸬鹚(Phalacrocorax carbo)雏鸟的生长发育进行了观察和研究。结果表明,在发育过程中,鸬鹚雏鸟跗蹠和嘴峰的发育早于翅和尾;通过体长与其它各生长指标的相对生长指数的计算,得出跗蹠和翅长的生长比体长快,嘴峰和尾长的生长比体长慢。另外,根据各生长指标特性的变化,将整个长长期划分为0~9日龄、10~23日龄、24~33日龄和34~离巢出飞4个生长阶段。
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Thiol-functionalized mesoporous ethane-silicas with large pore were synthesized by co-condensation of 1,2-bis(trimethoxy-sily)ethane (BTME) with 3-mercaptopropyltrimethoxysilane (MPTMS) using nonionic oligomeric polymer C1H (OCH(2)-CH(2))(10)OH (Brij-76) or poly(alkylene oxide) block copolymer (P123) as surfactant in acidic medium. The results of powder X-ray diffraction (XRD), nitrogen gas adsorption, and transmission electron microscopy (TEM) show that the resultant materials have well-ordered hexagonal mesoscopic structure with uniform pore size distributions. (29)Si MAS NNR, (13)C CP-MAS NMR. FT-IR, and UV Raman spectroscopies confirm the attachment of thiol functionalities in the mesoporous ethane-sificas. The maximum content of the attached thiol group (-SH) in the mesoporous framework is 2.48mmol/g. The ordered mesoporous materials are efficient Hg(2+) adsorbents with almost every -SH site accessible to Hg(2+). In the presence of various kinds of heavy metal ions such as Hg(2+), Cd(2+), Zn(2+), Cu(2+) and Cr(3+), the materials synthesized using poly(alkylene oxide) block cooollxmier (Pluronic 123) g(2+), as surfactant show almost similar affinity to Hg(2+), Cd(2+), and Cr(3+), while the materials synthesized using ofigomeric polymer C(18)H(37)(OCH(2)CH(2))(10)OH (Brij-76) as surfactant exhibit high selectivity to Hg(2+). (C) 2004 Elsevier Inc. All rights reserved.
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Liu, Yonghuai. Improving ICP with Easy Implementation for Free Form Surface Matching. Pattern Recognition, vol. 37, no. 2, pp. 211-226, 2004.
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This work is concerned with the accurate computation of flow in a rapidly deforming liquid metal droplet, suspended in an AC magnetic field. Intense flow motion due to the induced electromagnetic force distorts dynamically the droplet envelope, which is initially spherical. The relative positional change between the liquid metal surface and the surrounding coil means that fluid flow and magnetic field computations need to be closely coupled. A spectral technique is used to solve this problem, which is assumed axisymmetric. The computed results are compared against a physical experiment and "ideal sphere" analytic solutions. A comparison between the "magnetic pressure" approximation and the full electromagnetic force solutions, shows fundamental differences; the full electromagnetic force solution is necessary for accurate results in most practical applications of this technique. The physical reason for the fundamental discrepancy is the difference in the electromagnetic force representation: only the gradient part of the full force is accounted for in the "magnetic pressure" approximation. Figs 9, Refs 13.