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131.
132.
三个干燥加热斜长石的分析晶格参数表明,它们具有像合成斜长石那样“高”的有序度。它们的晶体结构分析证明,在过渡成分的高温斜长石中,具有一种意想不到的 Al、Si 有序度(Kroll 1978)。特别是 An27.8(于1160℃加热22天),在 T_1O 四面体位置有 t_1o—0.4Al,其它三个位置各自具有 t_1o—0.3Al[即〈t_1m〉=1/3(t_1m t_2O t_2m)—0.3Al。An52(于1255℃加热29天),具有 t_1o—0.48.Al,〈t_1m〉—0.35Al。An68.7(于1365℃加热42天),具有 t_1o—0.52Al,〈t_1m〉—0.39Al。这些数据需要用测量斜长石中 Al,Si 分配的图解,根据人们熟知的△131=20(131)—20(1 )参数以及晶格角γ进行估算。用△131和γ作为钙长石分子百分比的函数作图,并绘制 t_1o—〈t_1m〉图。用γ绘制的图可得到比较精确的结果,如果斜长石中正长石含量尚不知道的话,应使用这种图,但是晶格参数必须慎重地精选.△131值的测定是要容易得多,利用它确定结构状态的精确度却稍许差一些,但是要求正长石的含量必须是已知的.此外,如果不同样品的 t_1o—〈t_1m〉值对比较是富有意义的,还要求必须修正钙长石含量对△131的影响. 相似文献
133.
The purpose of this study is to quantify some of the parameters needed to perform near-field modelling of sites in the Kara Sea that were impacted by the disposal of radioactive waste. The parameters of interest are: the distribution coefficients (Kd) for several important radionuclides, the mineralogy of the sediment, and the relationship of Kd to liquid-to-solid ratio. Sediment from the Kara Sea (location: 73 degrees 00'N, 58 degrees 00'E) was sampled from a depth of 287 m on August 23/24, 1992. Analysis of the material included mineralogy, grain size and total organic carbon (TOC). Uptake kinetics were determined for 85Sr, 137Cs, 241Am, 99Tc, 1251, 232U and 210Pb and distribution coefficients (Kd) were determined for these radionuclides using batch type experiments. Sorption isotherms, developed for 137Cs, 85Sr and 99Tc, were linear in each case. Increasing the liquid-to-solid ratio strongly increased uptake of 137Cs and moderately increased uptake of 99Tc. Analysis for anthropogenic radionuclides indicated the presence only of 239/240Pu in the sediment with the highest activity (at the top section of the core) being 0.420 Bq kg(-1). Other anthropogenic radionuclides were below detection limits. 相似文献
134.
During August-September 1993, a joint Russian-United States expedition to the Bering and Chukchi Seas took place. Surface water samples were collected from 21 sites and separated into dissolved (duplicates) and suspended solids; 19 sediment and 6 air samples were also collected. These samples were analysed for 19 organochlorine pesticides, 11 chlorobenzenes and 113 PCB congeners. The report provides data on selected compounds which occured in > or = 75% of the water samples. Highest water concentrations were observed for HCH in open waters north and south of the Bering Strait, both regions being similar (alpha-HCH; 2.2 ng/L and lindane: 0.35 ng/L). Air levels observed were also constant (alpha-HCH; 0.041 ng/m3, lindane: 0.0093 ng/m3). Suspended solids and air particulares contributed little to the concentrations in their respective media, an observation common to all analytes except for the PCBs and the DDT residues. The sum of PCB concentrations in water were higher in the Bering Sea area compared to the Chukchi Sea (1.0 vrs 0.67 ng/L) and lower for air (0.46 vrs 0.23 ng/m3). Sum of DDT in water was higher in the Bering Sea than in the Chukchi Sea (0.23 vrs 0.15 ng/L) while in sediments and air, the Bering Sea concentrations were lower (0.95 vrs 1.6 ng/g and 36 vrs 56 pg/m3, respectively). Other organochlorine compounds for which data are presented include: pp'-DDE, pp'-DDT, dieldrin, HCB, 3 chlorobenzenes and 3 PCB congeners. Fluxes of all these chemicals through the Berin Strait are estimated; they ranged from 57 t/a (alpha-HCH) through 26 t/a (for sum of PCBs) to 0.2 t/a (pp'-DDE, dieldrin and 1,2,3-trichlorobenzene). Fugacity ratios for the HCHs and PCBs indicate the alpha-HCH is degassing in both the Bering and Chukchi Seas and that the gamma-isomer is degassing in the Bering Sea and is close to equilibrium (weakly absorbing) in the Chuchi Sea; the sum of PCBs are strongly absorbing in both areas. 相似文献
135.
The trends of malformation prevalence in embryos of dab, Limanda limanda, in the southern North Sea after the year 1990 mirrored the drop in major pollutants in the rivers draining into the German Bight. Despite this general decline, we detected a pollution event in the southern North Sea in winter 1995/1996 employing the prevalence of malformations in pelagic dab embryos as an indicator. An abrupt rise in malformation prevalence in the embryos of dab, corresponded to a dramatic increase in DDT levels in parent fish from the same area, indicating a hitherto unnoticed introduction of considerable quantities of DDT into the system. 相似文献
136.
94;1;F;H;H124_1;F094_1;苑杰;53-60清代东北马政探析王颖超;北京师范大学文学院 北京100875清代;;东北;;马政;;大凌河马场;;驿站清政府在东北实施的一系列与马有关的制度主要包括大凌河马场的设立和驿站、驿马的设置。顺治五年,清政府为了征战之需,在东北辽西设立大凌河马场,马场对维护和巩固清统治者的地位起到了重要的军事作用。清代末期,由于清政 相似文献
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139.
根据大量震源机制估计了2000年鸟取县西部地震(Mw=6.6)前后的区域应力场。为约束主震前的应力场,我们比较了主震产生的静态应力变化与主震后应力场的空间分布。在余震区的北部和中部,推测主震前的偏应力量值太大,不会受到静态应力变化的影响。主震前的最大主应力轴的方向与构造应力场一致。而在余震区南部,主震滑动较大的地区及其周围,发现由于静态应力变化较大,主震后应力场的空间分布很不均匀。在断层南端附近,静态应力变化的空间分布与余震的P轴方位角一致,推测主震前的偏应力量值小到足以受到静态应力变化(5MPa)影响的地步。断层南端原有余震断层面的强度可能特别弱。发现主震前的应力场在小于主震断层长度的尺度上是不均匀的。 相似文献
140.
Two kinds of observational data,fluctuation and mean profile measurements,from a 325 m meteorological tower in Beijing,China,are used to evaluate local scales of velocity and temperature for higher heights by flux-gradient mean profiles and eddy-correlation techniques.A comparison of these methods each other was made in terms of vertical turbulence fluxes for momentum and beat at the same heigbt.The vertical profiles of non-dimensional second moments.such as vertical turbulent fluxes of momentum and heat.velocity and temperature standard deviations,were derived by local similarity theory.The local similarity relations expressed that the vertical distributions of non-dimensional second moment variables were found to be functions of z/Λ and z/h in the stable boundary layer and the function of z/Zi for the convective boundary layer,where A the local Monin Obukhov(M-O) length. h the height of stable boundary layer and Zi the height of mixed-layer.These relations are shown to agree well with the observational data. 相似文献