131 resultados para 60-456


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1985年Kroto首先用质谱在激光蒸发石墨的氦气氛中检测到丰度占优势的以C_(60)和C_(70),从而以质谱法为主要手段的C_(60)研究迅速开展起来。一系列实验结果支持了Kroto猜测的C_(60)球形结构,并对C_(60)的气相反应行为有所认识。 1990年实现宏观量制取C_(60)后,气相C_(60)离子的研究内容更加广泛,Frieser在气相中

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足球状全碳烯 C_(60)具有丰富的化学性质,可以做为活泼的自由基捕捉试剂,在质谱常规化学电离源内气相 C_(60)可与 CCl_4,CHCl_3,CH_2Cl_2和 CHBr_3等产生的碎片发生化学反应,生成了[C_(60)CX_2]~+等多种气相衍生物离子.单独引入 CCl_4的离子源内存在着CCl_3~+(m/z117,100%),CCl_2~+(m/z82,22%),CCl~+(m/z47,24%)和 Cl+(m/z35,14%)阳离子、多种阴离子及 CCl_3,CCl_2,Cl 等自

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本文概述了C_(60)系列化合物的NMR谱、磁化率、磁性的某些进展。

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本文综述了各种新发现的C_(60)超导体及其研究进展,包括其超导转变温度制备方法,与氧化物陶瓷超导体的比较及目前存在的问题和今后的展望。

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在1.0~5.0GPa、700~1750℃条件范围内,对固熔体0.6NaAlSi_2O_6-0.4CaMgSi_2O_6进行了研究,探讨了该固熔体在高温高压下的存在行为,研究了由非晶态玻璃向翡翠转化过程中γT作用的相图,得到的透辉石翡翠的晶胞参数为α=0.9439nm,b=0.8573nm,c=0.5233nm,β=107.28°和V=0.41702nm~3。本实验中合成的宝石级翡翠为色泽温润,具有玻璃光泽,半透明的极富观赏性的透辉石翡翠。

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硅膜改性弹性玻璃毛细管柱做为一种新柱型,它具有类似弹性石英柱的柔性和惰性,也具有玻璃柱制作容易、材质易得的优点。硅膜做为固定相载体的色谱特性研究目前报道还很少,非极性硅酮相在其上的交联我们曾做过报

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Vegetation is very sensitive to climate change. Carbon isotopes in paleosol have been widely used to contruct the propotion of plants using C3 and C4 photosynthetic pathways. δ13C of Loess organic matter were analyzed on the loess- paleosols samples from Jingchuan sections and Luochuan S4—S5 sequence. This paper presents a long carbon isotope time series, covering the last 600kyr. δ13C record of Loess organic matter in Jingchuan is correlated with marine oxygen isotope records. Basing on former research work, this paper discusses temperature, rainfall and P CO2 effect on δ13Corg value. In the interglacial periods, carbon isotope is more sensitive than other proxies and indicates several climate fluctuations. The main conclusions are as follows: 1. Obtained δ13C composition from paleosols and loess sediments in Jingchuan range of -20.0‰ to -24.6‰, the maximum biomass of C4 is 35%, indicating a C3 and C4 mixed steppe with C3 dominated. C4 plant is not always expansion during paleosols periods. The minimum values of Jingchuan section appeared in S4 soil, and the vegetation was almost pure C3 plant at that time. δ13Corg value in S5-2 is also lower than loess in S5, reaching the minimum valus of S5 soil. 2. PCO2 variation has little impact on δ13Corg value in interglacial periods for the last 600kyr. The correlation between δ13Corg value curve and magnetic susceptibility curve as proxy of summer monsoon in general, means summer monsoon drive C4 plant expansion during glacial and interglacial. 3. The lowerδ13Corg values in S4 and S5-2 appear at Jingchuan and Luochuan, suggest origin from woodland or C3 grassland. Whatever vegetation it is, indicate strengthened East Asian summer monsoon and increase of precipitation. C4 plant percentage is lower in S5-1 and S1 which have stronger summer monsoon, than S0 and S2. And it also indicates increase of precipitation.δ13Corg values has not always non-linearity correlation with summer monsoon. 4. The maximum entroy spectral analysis of δ13C values of the last 600kyr indicates there is 21 kyr cycles in Loess sequence. It means that summer monsoon in the Chinese Loess Plateau also has the precession cycles like its origin low latitude.

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红山铜矿床位于三江地区义敦岛弧南端的中甸弧,是在晚三叠世甘孜-理塘洋盆向西俯冲过程中形成的一个中型规模的矽卡岩矿床。通常,矽卡岩体就是铜矿体或铜矿化体,主要呈似层状、层状、脉状及透镜体状产于大理岩与角岩接触带或局部在角岩中,未见其与侵入岩直接接触。通过对不同成矿阶段所形成的石榴石、磁铁矿、磁黄铁矿、黄铁矿、黄铜矿、方解石等典型矿物以及大理岩的稳定同位素特征研究,发现矽卡岩的最主要组成矿物石榴石的δ^18OSMOW范围为6.2—8.3‰,反映了矽卡岩可能直接继承隐伏斑岩体的氧同位素组成。根据磁铁矿的氧同位素组成(5.5—7.1‰)所计算的磁铁矿化阶段成矿流体的δ^18OSMOW为13.1—14.7‰(400℃)或12.5—14.1%。(500℃),暗示有富集δ^18O的CO2溶入到成矿流体中。硫化物的δ^34SCDT范围4.45—6.20‰,说明矿床具有高度均一的硫源,并且在硫化物的结晶沉淀过程中,流体中硫同位素分馏很弱。由此推测主成矿期成矿流体的δ^34S∑S为5.6±0.6‰。矿床中的大理岩的δ^13CPDB为2.0—2.2‰,δ^18OSMOW为24.0—24.8‰,说明大理岩是由海相碳酸盐岩经重结晶作用而成。成矿晚期阶段形成的方解石脉的δ^13CPDB范围是-2.4—1.7‰,δ^18OSMOW范围是16.3—22.4‰,表明其C和O主要来源于大理岩。总之,我们推测红山矽卡岩很可能主要是由中酸性岩浆浅成侵位时局部同化碳酸盐围岩所形成的一种富含钙质成分的次生岩浆就位于碎屑岩与碳酸盐岩之间的构造薄弱带冷凝固结而成,矽卡岩型矿化与深部斑岩型矿化具有共同的成矿物质和成矿流体来源。

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根据对高青-平南断裂带两侧的气藏进行气体组分及碳同位素地球化学分析发现:两侧分布的是不同的气体类型,南侧主要是以甲烷为主的烃类气藏,其CH4含量在88.83%-99.26%之间,碳同位素值为-55.17‰~ -35.00‰之间,结合该地区的地质特征认为该区CH4气藏为混合气藏,其来源主要有3种:油型伴生气、幔源岩浆脱气以及CO2还原气。而北侧主要是以CO2为主的非烃类气藏,其CO2含量在60.72%-99.99%之间,碳同位素值为:9.8‰-3.41‰,3He/4He值主要在4.45×10^-6~6.35×10^-6之间,主要是幔源-岩石化学成因的混合气。通过分析两侧气体组分及碳同位素特征,初步判断高青-平南断裂带两侧烃类气体形成于同一时期,主要可能是早期强烈的岩浆喷发后形成,而高青地区的二氧化碳气藏主要是由后期的岩浆脱气形成。两类气藏组分差异的最主要原因是由后期的岩浆活动影响造成.