976 resultados para 809.812
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This paper reports the mega-, micro-sporogenesis and female-, male-gametogenesis of Swertia cincta for the first time, with the aim of discussing the systematic position of section Platynema and section Ophelia of Swertia. Anthers are tetrasporangiate. The development of anther walls conforms to the dicotyledonous type. The tapetum cells have dual origin and are similar to the glandular type. There are two middle layers. The endothecium and epidermis persist. Cytokinesis in the microsporrocyte meiosis is simultaneous type and the microscpore teads are tetrahedral. Pollen grains are 3-celled. The ovary is bicarpellum and unilocular. The placentation is of suparietal placentation with 12 series of ovules. The ovules. The ovule is unitegmic, tenuinucellar and ana-campylotropous, The embryo sac orignates from the single-archesporial cell. The one chalazal megaspore in lienar tetrad become the functional megasore. The development of embryo sac is of the polygonum type. Before fertilization, two polar nuclei fuse into one secondary nucleus. Three antipodal cells persisted and divided into 5-8 cells. A comparison between two sections indicates that section Plathnema is better treated as distinct section and is more advanced than section Ophelia according to the evolutionary trends of embryological characters.
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在贵州喀斯特区域一块典型的退耕弃荒洼地中央和周边坡面采集了4个土壤剖面,研究土壤有机碳(SOC)含量和δ^13Corg值的变化.结果表明,坡面不同土壤层次SOC的变化范围为6.0-92.3 mg·kg^-1,并沿着土壤层次的加深迅速降低,变化幅度远远大于洼地土壤剖面(6.3-26.7 mg·kg^-1).坡面土壤δ^13Corg介于-25.103‰和-23.666‰之间,但各剖面土层内部δ^13Corg变化趋势不一致.洼地土壤δ^13Corg介于-23.495‰和-20.809‰之间,并随着土壤层次的加深δ^13Corg逐渐增加.洼地土壤剖面层次内C4-C占SOC的比例随土壤层次的加深逐渐增加,与林-农生态系统转变过程中的变化趋势相反;土壤δ^13Corg与C3-C之间呈显著相关性(R^2=0.7806,n=7),对δ^13Corg起到主要影响作用的是退耕弃荒后新加入的C3-C.
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利用YJ-3000t压力机,在2.0GPa、室温至1200℃条件下,测量了新疆库地地区斜长角闪岩的纵波速度(vp)和力学品质因子(Q值)。实验结果表明:斜长角闪岩的vp和Q值随温度的升高而降低,在升温的初始阶段,vp和Q值随温度下降的幅度较小,随着温度的升高其下降的幅度逐渐增大;由于斜长角闪岩的各向异性,导致了在三个方向上vp随温度而下降的幅度显著增大时的温度不同,其中x和y方向为812℃,z方向为673℃。而在各方向上的Q值随温度下降的幅度显著增大时的温度相差不大,约为812℃。观察回收的实验产物表明:当温度大于647℃时,产物中开始出现熔体,vp在x和y方向上的下降幅度没有明显的变化,而在x方向上的下降幅度增大;此时熔体对Q值的影响不大。当温度大于812℃时,产物中的熔体含量明显增多,vp和Q值下降的幅度都显著增大。据此认为,部分熔融是弹性波速度减小和衰减增大的主要原因.
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岩石化学与微量元素研究表明,在强经泥质灰岩中,SiO2和Au、As、Sb含量增高,CaO、CO2和MgO含量降低;在强碳酸盐化泥质灰岩中,AgO和CO2含量增高,SiO2含量降低;不同蚀变与矿化岩石的稀土含量和配分模式与未蚀变泥质灰岩基本一致。流体包裹体研究揭示,成矿溶液为富Cl^-型和富SO4^2-型,爆裂温度为183-378℃。同位素研究指示,δ^34S=(6.471-21.965)×10^-3,δ^18O=(9.3-11.6)×10^-3,δD=(-70--77)×10^-3,^206Pb=19.551-20.05,^027Pb/^204Pb=15.690-16.240,^208Pb/^204Pb=38.710-40.137;成矿流体具有岩浆水和大气降水相混合的特点,成矿物质具有壳-幔混合特征。
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香山基性—超基性杂岩体位于新疆哈密境内,地理坐标为东经94°30'-94°37',北纬42°15'-42°20'。本文研究了该岩体的岩石学、地球化学、矿物学特征。最后提出了关于香山岩体成因的假设。香山岩体的主体是辉长苏长岩,它占整个杂岩体出露地表面积的绝大部分,其它岩石类型有斜长方辉橄榄岩、(斜长角闪)二辉橄榄岩,(斜长角闪)单辉橄榄岩、(角闪)橄榄辉长(苏长)岩,辉长岩。岩体中各种岩石均为中粗粒结构,块状构造。显微结构最特征的是包含结构,还有辉长结构,反应边结构,金属矿物较多时具海绵陨铁结构。主要蚀变类型有蛇纹石化,还有绿泥石化,透闪石化,滑石化、绢石化、钠黝帘石化、碳酸盐化等。杂岩体中的超基性岩的m/f = 1.9-4.6,属于铁质超基性岩,为与铜镍矿床有关的岩石类型。各种岩石在久野(1966)的Na_2O + K_2O → SiO_2变异图中,大部分属于碱性玄武岩系。但由于在CIPW标准矿物组成和薄片不均未发现富碱矿物(霞石或白榴石),因此,认为岩体的母岩浆是一种过渡型的碱性橄榄玄武岩浆。岩石的微量元素含量,从方辉橄榄岩至辉长苏长岩,随着基性度减小,Ti、V、Zn、Sr、Ba逐渐增加。Cr、Ni、Co、Cu逐渐减小。所有岩石均呈轻稀土富集型,从方辉橄榄岩、二辉橄榄岩、单辉橄榄岩直至辉长苏长岩,稀土总量和轻重稀土比L/HREE逐渐增加。方辉橄榄岩有Eu轻微正异常 、二辉橄榄岩Eu轻微负异常。单辉橄榄岩是具较大的Eu正异常,辉长苏长岩有正的或负的Eu异常,所有的岩石均具Ce轻微负异常。岩体中各种造岩矿物橄榄石为贵橄榄石,单斜辉石为顽透石或普通辉石,斜长石为拉长石,角闪石则为钙角闪石。岩石中各种矿物的结晶温度(用不同方法计算的结果比较一致)分别为:橄榄石1455~1654 ℃,单斜辉石976~1150 ℃(与母岩类型有关),斜长石1100 ℃左右,角闪石812-1002 ℃(与母岩有有关。岩体的母岩浆是在1200 ℃,25.9Kb(约80 KM深处)条件下上地幔岩经8-9%的部分熔融产生的(用平衡部分熔融状型计算得出)。岩浆结晶过程可用F_o-D_i-An三元相图定性说明,依次结晶生成:纯橄榄岩(未见)→ 辉石橄榄岩(方辉橄榄岩、二辉橄榄岩、单辉橄榄岩) → 橄榄辉长苏长岩,由于实际情况复杂,还有其它岩石类型生成。
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Ginseng is one of the most expensive Chinese herbal medicines and the effectiveness of ginseng depends strongly on its botanical sources and the use of different parts of the plants. In this study, a microchip electrophoresis method coupled with the polymerase chain reaction (PCR)-short tandem repeats (STR) technique was developed for rapid authentication of ginseng species. A low viscosity hydroxypropyl methylcellulose (HPMC) solution was used as the sieving matrix for separation of the amplified STR fragments. The allele sizing of the amplified PCR products could be detected within 240 s or less. Good reproducibility and accuracy of the fragment size were obtained with the relative standard deviation for the allele sizes less than 1.0% (n = 11). At two microsatellite loci (CT 12, CA 33), American ginseng had a different allele pattern on the electropherograms compared with that of the Oriental ginseng. Moreover, cultivated and wild American ginseng can be distinguished on the basis of allele sizing. This work establishes the feasibility of fast genetic authentication of ginseng species by use of microchip electrophoresis.
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Charman, D. West, S. Kelly, A. Grattan, J. environmental change and Tephra Deposition: the strath of Kildonan, Northern Scotland. Journal of Archaeological Science. 1995. 22 pp 799-809
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McInnes, C., Lee, K. (2006). Health, security and foreign policy. Review of International Studies, 32 (1), 5-23. RAE2008
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Breen Smyth, M. (2005). Insider Outsider issues in researching violence and divided societies. In E. Porter, G. Robinson, M. Smyth, A. Schnabel, and E. Osaghae (Eds.), Researching Conflict in Africa: Insights and Experiences (pp.9-23). Tokyo: United Nations University Press. RAE2008