共查询到20条相似文献，搜索用时 801 毫秒
1.
K_2O-Al_2O_3-SiO_2-H_2O体系形成一些主要造岩矿物,如长石、石英和云母等,因此受到有关学者的广泛重视。为了探讨岩石的形成机制,国外许多学者曾研究过该体系矿物的稳定范围。近年来,伊万诺夫、J.W.谢德(Shade)、R.P.温特施(Wintsch)、D.M.伯特(Burt)、H.W.戴(Day)和J.J赫姆利(Hemley)等也先后用热力学方法研究过该体系的相平衡关系。但至今,该体系中某些矿物的相平衡关系仍然有争议,例如, 相似文献
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１金属基板上ＳｉＯ２ ＴｉＯ２ ＺｒＯ２陶瓷涂层工艺的研究现状在金属基板上进行Ｓｏｌ ｇｅｌ涂层是国外在９０年代发展起来的一项新工艺。根据金属陶瓷复合材料这一新兴工业的应用前景,一些工业发达国家的政府研究部门和工业界都十分重视这项新工艺的开发与研究,... 相似文献
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本文用抽空石英管法对三元硫化物体系Ag_2S-Cu_2S-PbS和Ag_2S-Cu_2S-Bi_2S_3在500℃的相图进行了研究。 Ag_2S-Cu_2S-PbS体系500℃相关系,受方铅矿和固溶体f.c.c.(Ag_xCu_(2-x)S)、b.c.c.(Cu_xAg_(2-x)S)所控制。在接近PbS-Cu_2S连线处有一液相区。随温度下降,方铅矿可与Cu_2-Ag_2S二元系上所有各相平衡共存。 Ag_2S-Cu_2S-Bi_2S_3体系在500℃时则包含六个固溶体,即块硫铋银矿、铜银铅铋矿、杂硫铋银矿、硫铋铜矿、CuBi_3S_5、Cu_3Bi_5S_9和新合成“C”(Ag_(1.1)Cu_(4.8)Bi_(5.8)S_(12))。最令人感兴趣的是无铜、无铅的铜银铅铋矿(Ag_2Bi_4S_7)合成成功。 以上二个三元系中矿物稳定性及共生关系也根据相图研究结果进行了讨论。 相似文献
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M. Wildner 《Mineralogy and Petrology》1993,48(2-4):215-225
Summary Crystals of K2[Co2(SeO3)3]-2H2O and K2[Ni2(SeO3)3]-2H2O were synthesized under low-hydrothermal conditions. Their structures were determined using single crystal X-ray data up to sin / = 0.7Å-1. [Space group P63/m; a = 9.091(3),9.016(2)Å; c = 7.562(2), 7.476(2)Å; Z = 2; RW = 1.6, 2.5%]. The investigations confirmed that K2[Co2(SeO3)3].2H2O and K2[Ni2(SeO3)3]-2H2O represent the first selenites belonging to the zemannite structure type, a framework structure with wide channels running parallel [0001]. In both compounds four maxima were clearly located in the channel by Fourier summations and attributed to two K atoms and two H2O molecules, each with an occupancy factor of 1/6; a possible ordering scheme (full occupancy) with local symmetry 1 and [6]-coordinated K atoms could be derived for the channel atoms.Zusammenfassung Kristalle von K2[Co2(SeO3)3]-2H2O und K2[Ni2(SeO3)3]-2H2O wurden unter niedrig-hydrothermalen Bedingungen synthetisiert. Die Strukturen wurden unter Verwendung von Einkristallröntgendaten bis sin /= 0.7Å-1 bestimmt. [Raumgruppe P63/m; a = 9.091(3), 9.016(2)Å; c = 7.562(2), 7.476(2)Å; Z = 2; RW = 1.6, 2.5%] Die Untersuchungen bestätigten, daß K2[Co2(SeO3)3] - 2H2O und K2 [Ni2(SeO3)3] - 2H2O als erste Selenite dem Strukturtyp des Zemannits angehören, einer Gerüststruktur mit weiten, parallel [0001] verlaufenden Kanälen. In beiden Verbindungen wurden im Kanal vier Maxima durch Fourier-Summationen eindeutig lokalisiert und zwei Kalium-atomen sowie zwei H2O Molekülen, jeweils mit einem Besetzungsfaktor von 1/6, zugeschrieben. Für die Kanalatome konnte ein möglicher Ordnungszustand (volle Besetzung) mit lokaler Symmetrie 1 und [6]-koordinierten Kaliumatomen abgeleitet werden.
Dedicated to Prof. Dr. Josef Zemann at the occasion of his 70th birthday
With 2 Figures 相似文献
Selenite des Zemannittyps: Kristallstrukturen von K2[Co2(SeO3)3] - 2H2O und K2[Ni2(SeO3)3]-2H2O
Dedicated to Prof. Dr. Josef Zemann at the occasion of his 70th birthday
With 2 Figures 相似文献
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V. G. Thomas S. Z. Smirnov O. A. Kozmenko V. A. Drebushchak V. S. Kamenetsky 《Petrology》2014,22(3):293-309
In order to determine the mechanisms of formation and properties of natural hydrosilicate liquids (HSLs), which are formed during the transition from magmatic to hydrothermal mineral formation in granitic pegmatites and rare-metal granites, the formation of HSLs was experimentally studied in the Na2O-SiO2-H2O, Na2O-Al2O3-SiO2-H2O, and Na2O-K2O-Li2O-Al2O3-SiO2-H2O systems at 600°C and 1.5 kbar. It was shown that the sequential extension of composition does not suppress HSL formation in the systems and expands the stability field of this phase. However, HSLs formed in extended chemical systems have different structure and properties: the addition of alumina induces some compression of the structure of the silicate framework of HSLs, which results in a decrease in water content in this phase and probably hinders the reversibility of its dehydration. It was demonstrated that HSL can be formed by the coagulation of silica present in a silica-oversaturated alkaline aqueous fluid. It was supposed that the HSL formed during this process has a finely dispersed structure. It was argued that anomalous enrichment in some elements in natural HSLs can be due to their sorption by the extensively developed surface of HSL at the moment of its formation. 相似文献
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离子色谱法测定水样中S2-、SO2-3、SO2-4、S2O2-3 总被引：1，自引：0，他引：1
该种方法利用离子色谱仪的电导检测器与电化学检测器串联,十几分钟即可连续完成水中S2-、SO2-3、SO2-4、S2O2-3的测定,方法具有快速、高效、方便、灵敏、选择性好等特点.方法的检出限分别为S2-12.5μg/L;SO2-3 22.4μg/L;SO2-4 5.0μg/L;S2O2-3 5.0μg/L.相对标准偏差在1.5%～6.9%之间,能够满足水中S2-、SO2-3、SO2-4、S2O2-3四种阴离子分析测试的需要. 相似文献
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为了计算高温，高压和高密度流体的热力学性质，提出了一个具有19个参数的维里型状态方程，其中参数与温度间的函数关系采用由Sutherland位能函数导出的维里系数近似式。除临界点附近以外，在已报道的pVT数据所覆盖的大部分超临界区域内，该方程均可适用。用该方程对H2O，CH4，H2，CO2，CO和O2等流体pVT关系的计算结果令人满意，其中pVT上限分别为：91-610GPa,1.6-11.0cm^3/mol,4000-5000K。计算体积的平均偏 小于0．8％，最大偏差小于5．4％。 相似文献
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Polarized single crystal absorption spectra, in the spectral range 40 000–5 000 cm-1, were obtained on Co2+ in trigonally distorted octahedral oxygen fields of buetschliite-type K2Co(SeO3)2 (I), K2Co2(SeO3)3 (II) and zemannite-type K2Co2(SeO3)3 · 2H2O (III). Site symmetries of Co2+ are
m (D3d) in I, 3m (C3v) in II, and 3 (C3) in III. The spectra can be interpreted on the basis of an electric dipole mechanism, wherein transitions of Co2+ in the centrosymmetric site in I gain intensity from dynamic removal of the inversion centre by vibronic coupling. In accordance with the elongation of the CoO6 octahedra along the trigonal axis, the split component E(g) of the ground state 4T1g in octahedral fields is the ground state in all three compounds. Trigonal field parameters Dq(trig), D, D and the Racah parameters B have been fitted to the energies of spin allowed transitions (293 K) as follows: I: 744, 94, -16, and 838 cm-1, resp.; II: 647, 227, 42, and 798 cm-1, resp.; III: 667, 181, 21, and 809 cm-1, respectively. Racah parameters C were estimated from the energy of some observed spin-forbidden transitions to be 3770 (I), 3280 (II), and 3465 cm-1 (III). Values of Dq and of the Racah parameters B and C indicate slight differences of Co2+-O bonding in I as compared to II and III, with somewhat higher covalency in compounds II and III which contain face-sharing CoO6 octahedra with short Co-Co contacts. Also, in II and III the observed D values do not agree with theoretical D values, predicted from the magnitude of the mean octahedral distortions. 相似文献
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吕明1，2，汤良杰1，2 总被引：1，自引：0，他引：1
通过系统的地震资料综合解释,对塔里木盆地巴楚隆起卡拉沙依断裂上、下盘沉积地层厚度的变化及各界面与上、下部地层的接触关系、不整合面的发育特征及变化规律进行研究,以此来探讨卡拉沙依断裂各时期的活动特征。认为卡拉沙依断裂东、西两段呈现出截然不同的活动特征。主断裂东段,晚寒武世-奥陶纪,断裂无明显活动;早志留世晚期-早二叠世,断裂开始活动,呈现出逆冲推覆断裂的特征;经中二叠世的平静期,从晚二叠世开始又有一次逆冲推覆活动。而位于主断裂南侧的次级断裂,在晚寒武纪-中志留世,断裂无明显活动;从早中泥盆世开始,次级断裂开始活动,表现为压性断裂特征,逆冲推覆作用持续至早二叠世,经过中二叠世短暂的平静期,在晚二叠世还有一次继承性活动,但活动强度较弱。主断裂西段,奥陶纪时期,断裂开始活动并表现出张性断裂活动特征;经过志留纪-中二叠世的平静期,从晚二叠世开始,断裂西段发生正反转作用,逆冲推覆活动明显。次级断裂西段,在晚寒武世-早中二叠世并无活动,从晚二叠世开始,断裂开始活动,表现为强烈的逆冲推覆作用。 相似文献
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以钛酸四丁酯为前驱体,天然凹凸棒石为载体,采用溶胶凝胶法制备了TiO_2/凹凸棒石复合光催化剂,并用XRD、TEM对其进行表征.以亚甲基蓝染料为模拟污染物,采用300 W汞灯为紫外光源,以光催化实验来评价该催化剂的活性,并研究了H_2O_2的引入对光催化活性的影响.实验结果表明,H_2O_2能显著提高染料的脱色效率:亚甲基蓝的初始浓度为50 mg/L,催化体系为2 mmol/L H_2O_2+0.5 g/L TiO_2/凹凸棒石+UV(紫外线),光催化10 min后其脱色率为95%,相对于单独的0.5 g/L TiO_2/凹凸棒石+UV催化体系,其脱色率提高了约50%.全波段扫描显示,加入H_2O_2后,亚甲基蓝在290 nm对应的苯环吸收蜂急剧下降,665 nm对应的最大吸收峰则近乎消失,且没有新的吸收峰产生. 相似文献
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The configurational heat capacity, shear modulus and shear viscosity of a series of Na2O–Fe2O3–Al2O3–SiO2 melts have been determined as a function of composition. A change in composition dependence of each of the physical properties
is observed as Na2O/(Na2O + Al2O3) is decreased, and the peralkaline melts become peraluminous and a new charge-balanced Al-structure appears in the melts.
Of special interest are the frequency dependent (1 mHz–1 Hz) measurements of the shear modulus. These forced oscillation measurements
determine the lifetimes of Si–O bonds and Na–O bonds in the melt. The lifetime of the Al–O bonds could not, however, be resolved
from the mechanical spectrum. Therefore, it appears that the lifetime of Al–O bonds in these melts is similar to that of Si–O
bonds with the Al–O relaxation peak being subsumed by the Si–O relaxation peak. The appearance of a new Al-structure in the
peraluminous melts also cannot be resolved from the mechanical spectra, although a change in elastic shear modulus is determined
as a function of composition. The structural shear-relaxation time of some of these melts is not that which is predicted by
the Maxwell equation, but up to 1.5 orders of magnitude faster. Although the configurational heat capacity, density and shear
modulus of the melts show a change in trend as a function of composition at the boundary between peralkaline and peraluminous,
the deviation in relaxation time from the Maxwell equation occurs in the peralkaline regime. The measured relaxation times
for both the very peralkaline melts and the peraluminous melts are identical with the calculated Maxwell relaxation time.
As the Maxwell equation was created to describe the timescale of flow of a mono-structure material, a deviation from the prediction
would indicate that the structure of the melt is too complex to be described by this simple flow equation. One possibility
is that Al-rich channels form and then disappear with decreasing Si/Al, and that the flow is dominated by the lifetime of
Si–O bonds in the Al-poor peralkaline melts, and by the lifetime of Al–O bonds in the relatively Si-poor peralkaline and peraluminous
melts with a complex flow mechanism occurring in the mid-compositions. This anomalous deviation from the calculated relaxation
time appears to be independent of the change in structure expected to occur at the peralkaline/peraluminous boundary due to
the lack of charge-balancing cations for the Al-tetrahedra. 相似文献
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该种方法利用离子色谱仪的电导检测器与电化学检测器串联，十几分钟即可连续完成水中S^2-、SO3^2-、SO4^2-、S2O3^2-的测定，方法具有快速，高效，方便，灵敏，选择性好等特点。方法的检出限分别为：S^2-12.5μg/L；SO3^2-22.4μg/L;SO4^2-5.0μg/L；S2O3^2-5.0μg/L。相对标准偏差在1.5%-6.9%之间，能够不中S^2-、SO3^2-、SO4^2-、S2O3^2-四种阴离子分析测试的需要。 相似文献