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311.
Chemical and spectral analyses are given for 16 sphalerites from Yugoslavia. Since they were formed under various conditions the content of Fe and other metals (Mn and Cd especially) varies widely. The relation between the dimensions of elementary cell and the molar percent of FeS in the sphalerites of Yugoslavia shows only slight differences from Vegard's rule. The indices of refraction and reflectivity as well as dispersion for the wavelengths 440, 460, 480, 500, 540, 580, 620, and 660 nm were measured. For the wavelengths mentioned, diagrams are given showing the relation between reflectivity and microhardness of sphalerite and its chemical composition.
Zusammenfassung Für 16 jugoslawische Zinkblenden wurde die chemische Zusammensetzung und spektralanalytisch der Gehalt an Spurenelementen ermittelt. Da die Zinkblenden unter sehr verschiedenen Bedingungen entstanden, schwankt ihr Gehalt an Fe und anderen Metallen, besonders Mn und Cd stark. Die Verhältnisse zwischen der Größe der Elementarzelle und den Molprozenten von FeS zeigen nur geringe Abweichungen von der Vegard-Regel. Für die Wellenlängen 440, 460, 480, 500, 540, 580, 620 und 660 nm wurden Refraktionsindices, Absorptionskoeffizient und Reflexionsvermögen ermittelt. Die Beziehungen zwischen Reflexionsvermögen, Mikrohärte und chemischer Zusammensetzung werden in Diagrammen dargestellt.
  相似文献   
312.
合肥盆地周缘中石炭系-二叠系碎屑岩的成分成熟度和结构2成熟度较高,成岩后生作用强烈,特别是强的机械压实作用和成岩自生矿物的多期胶结作用,使其孔隙结构和储集物性变差。盆地南缘石炭系碎屑岩成岩强度更强,孔隙结构更差。碎屑岩的孔隙类型多样,以构造裂隙和次生孔隙为主,且裂隙和次生孔隙的形成呈多期性,先期形成的次生孔隙不同程度地被后期的自生矿物充填。  相似文献   
313.
Coherency stress and coherency strain energy generated by Na+?K+ ion exchange in alkali feldspars are calculated using an isotropic model, and deformation of single crystals of alkali feldspars exposed to molten alkali chlorides at \(P_{H_2 O} \) < 1 bar is described. Coherency stress in alkali feldspars can reach 10–20 kb. When it is large, partial relaxation by fracture and/or plastic deformation takes place under anhydrous conditions, but temporary build-up of stress is unavoidable even under hydrothermal conditions. Because of coherency strain energy, a thin layer of an end-member alkali feldspar produced by cation exchange on a grain of the other end-member alkali feldspar would be unstable with respect to dissolution. Therefore, under hydrothermal conditions one end-member alkali feldspar replaces the other by dissolution and precipitation. The mechanism of the reaction $$Na_x K_{1 - x} AlSi_3 O_{8_{(feld.)} } + yK^ + \rightleftharpoons Na_{x - y} K_{1 + y - x} AlSi_3 O_{8_{(feld.)} } + yNa^ + $$ is primarily controlled by \(P_{H_2 O} \) and by ΔK/(Na + K), the difference between the equilibrium value and the initial value of the atomic K/(Na + K) ratio of the feldspar. When ¦ΔK/(Na + K)¦ is small, the reaction proceeds by cation exchange. When ¦ΔK/(Na + K)¦ is large, cation exchange still occurs if \(P_{H_2 O} \) is very low, but under hydrothermal conditions replacement by dissolution and precipitation occurs.  相似文献   
314.
相邻建筑结构的模糊振动控制   总被引:14,自引:1,他引:14  
本文研究了相邻建筑结构的模糊控制问题。首先,介绍相邻建筑结构体系的特点,建立体系的力学模型及运动方程;然后,进行了半主动控制研究,提出了控制的方法;最后,利用模糊控制方法实现了结构的智能控制。通过以上研究,说明相邻建筑结构相互振动控制是十分有效的,所得出的结论对实际工程的应用具有指导意义。  相似文献   
315.
Pleistocene aeolian sands and alluvial deposits can frequently be traced along the Mediterranean coast. Such deposits also exist along the eastern Adriatic coast and the nearby islands. Four stratigraphical sections of these deposits were studied on the Island of Hvar with the purpose of establishing a chronological framework of the aeolian–alluvial depositional system, using luminescence dating and magnetic susceptibility stratigraphy. Luminescence dating was applied on coarse‐grained feldspar and quartz grains separated from the sands. Both quartz optically stimulated luminescence (OSL) and feldspar post‐IR infrared stimulated luminescence (pIRIR) age estimates are in good agreement, with values ranging between 167±24 to 120±12 ka (OSL) and 179±18 to 131±18 ka (pIRIR measured at 290 °C) after a fading correction for the pIRIR signal. The results can be clearly correlated to around the end of oxygen isotope stage (OIS) 6 and the beginning of OSI 5, indicating that the aeolian accumulation of sands was a result of the Penultimate Glacial and climate fluctuations at the beginning of the Last Interglacial. Variations in magnetic susceptibility (MS) data can be interpreted alongside these dating results; several stronger peaks detected at the very end of the Penultimate Glacial and the initial stage of the Last Interglacial cycle most probably indicates more intensive pedogenesis resulting from a more favourable climate, probably because of climate changes. Breccias related to major bounding surfaces in association with evidence of soil formation and bioturbation could be the result of more favourable climate conditions and changes during the transition from OIS 6 to OIS 5 (Penultimate Glacial–Last Interglacial). These results are in agreement with similar data from the wider Mediterranean area.  相似文献   
316.
1 Introduction Microsatellites or simple sequence repeats (SSRs) are tandemly repeated motifs of one to six bases found in all prokaryotic and eukaryotic genomes analysed to date (Zane et al., 2002). Due to their hyper-variable and co-dominant nature, relatively high abundance and random distribution in the genome, microsatellites are among the most efficient class of molecular markers. Such repeats display high polymorphism because of variation in repeat length and can be rapidly analysed t…  相似文献   
317.
所讨论的垂直构造是石油勘探中最常见的小尺度局部升降作用所引起的各种构造 ,按成因可分为跨塌构造、压实构造、底辟构造三类样式。垮塌构造样式是碎屑岩沉积盆地基底的碳酸盐岩地层长期被地下水溶解形成地下大溶洞 ,造成上部地层垮塌而形成的堑背形构造样式 ;压实构造由沉积压实作用所致 ,可分为基底古隆起披覆构造样式和差异压实披覆构造样式等 ;底辟构造 (又称“挤入构造”)是塑性岩层在外力作用下发生底辟作用而产生的 ,分刺穿底辟和拱形底辟两种 ,或冷底辟和热底辟两类。莺歌海盆地发育众多的地震异常体 ,呈底辟状 ,但比较特殊 ,可称为气烟筒 ,与通常的底辟具本质之别。中国东部中、新生代盆地中普遍发育垂直构造 ,它们与沉积作用同步发生 ,一般无明显的挤压褶皱变形  相似文献   
318.
Our analysis of BV RI light curves for the cataclysmic variable UX UMa obtained in intermediate activity states, in the transition between the active and quiescent states of the system on March 12, 1997 and May 3, 2000, shows that the shapes of these light curves cannot be adequately described using the standard hot-spot model. A model with a “hot line” near the edge of the disk and a two-armed spiral structure on the disk surface reproduces much better out-of-eclipse variations in the light curves. The presence of an extended hot line can explain the anomalous shape of the I light curve on March 12, 1997. The decrease in the observed luminosity of the system between March 12, 1997 and May 3, 2000 could be due to a decrease in the disk luminosity by a factor of 2–2.5; the higher disk luminosity on the earlier date is associated with appreciable deviations of the radial temperature distribution of the disk material from that for the standard model. The phases and depths of dips in the out-of-eclipse sections of the UX UMa light curves are due primarily to the parameters of the complex shape of the accretion disk, which has a spiral structure located mainly near its outer edge. The contribution of the spiral arms in the V filter reaches 20–50% of the total disk radiation. The crest of the first spiral wave in our model maintains its approximate position in azimuth; this structure could represent a bulge in a halo at the outer edge of the disk near orbital phases φ ~ 0.7, in the direction of the continuation of the extended shock in the disk itself. The position of the crest of the second spiral arm changes with time. This structure may represent a one-armed spiral wave near the apastron of the weakly elliptical disk. Finally, the observations testify to the presence of another spiral arm that is les clearly manifest in terms of both its luminosity and its height above the unperturbed disk surface. Thus, in an intermediate activity state of UX UMa, the surface of the accretion disk is distorted by the action of a two-armed spiral structure in the outer regions of the disk, which is asymmetric in both its luminosity and dimensions, and a bulge at the disk edge in the region of its interaction with the inflow to the disk.  相似文献   
319.
The reactivity of dissolved iron compounds towards different pollutants and photooxidants in atmospheric liquid water depends upon the oxidation state and speciation of iron. Our measurements of the oxidation state of dissolved iron eluted from aerosol particles (Dae: 0.4–1.6 m) collected in the urban atmosphere of Ljubljana showed that a large fraction of the iron content is present as Fe(II). The concentration ratio [Fe(II)]/[Fe(III)] varied between 0.9 and 3.1. The kinetics of S(IV) autoxidation catalyzed by Fe(II) under the conditions representative for acidified atmospheric liquid water and the influence of oxalate on this reaction under dark conditions was investigated. The reaction rate is the same if Fe(II) or Fe(III) is used as a catalyst under the condition that Fe(II) can be oxidized in Fe(III), which is the catalytically active species. Oxalate has a strong inhibiting effect on the S(IV) autoxidation in the presence of Fe(II). The reaction is autocatalytic with an induction period, that increases with higher concentrations of oxalate. The inhibiting effect of oxalate differs according to whether iron is initially in the Fe(II) or Fe(III) state. However, in both cases the inhibition by oxalate is a result of the formation of complexes with the catalyst.  相似文献   
320.
张家口北部侏罗纪聚煤盆地的生成主要在中生代中侏罗世早期(陈顺等,1988;范和平,1989;刘晓文等,2005;谢明忠等,1996;张建军,2006)。在中生代之前该区地壳处于长期稳定的“地盾”构造状态(袁东翔,2006)。早侏罗世晚期地盾开始活化,至中侏罗世早期聚煤盆地开始形成,在一些山间盆地内沉积形成了侏罗系下花园组含煤地层(袁东翔,2006)。笔者通过对该区已知煤炭资源赋存状态,以及已有地质勘查成果的分析研究后认为:该区中侏罗世早期聚煤盆地,主要生成在由不同方位的古陆或构造带所形成的交角构造区(童玉明,1992);下花园组含煤建造是在较强的水动力条件下、陆源碎屑物质沉积速率较快的沉积环境中形成的(陈忠惠,1988;韩德馨等,1980;李思田等,1988;刘宝珺等,1980);可采煤层主要富集在盆地次边缘以及特定部位和冲积扇远端的扇前三角洲或扇面分流河道之间的相对较稳定的聚煤环境中(王定武等,2005;王洪力,2006;王思恩,1994;王相会,1998);煤系及煤层主要保存在后期改造作用较弱和相对稳定或持续缓慢沉降的构造环境中(王定武等,2005;王洪力,2006;王思恩,1994;王相会,1998)。在这些新认识的基础上提出了几个聚煤预测区,为该区下一步的预查找煤工作指明了方向。  相似文献   
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