Formation of Al-rich titanite (CaTiSiO4O–CaAlSiO4OH) reaction rims on ilmenite in metamorphic rocks as a function of fH2O and fO2

Reaction rims of titanite on ilmenite are described in samples from four terranes of amphibolite-facies metapelites and amphibolites namely the Tamil Nadu area, southern India; the Val Strona area of the Ivrea-Verbano Zone, northern Italy, the Bamble Sector, southern Norway, and the northwestern Austroalpine Ötztal Complex. The titanite rims, and hence the stability of titanite (CaTiSiO₄O) and Al–OH titanite, i.e. vuaganatite (hypothetical end-member CaAlSiO₄OH), are discussed in the light of fH₂O- and fO₂-buffered equilibria involving clinopyroxene, amphibole, biotite, ilmenite, magnetite, and quartz in the systems CaO–FeO/Fe₂O₃–TiO₂–SiO₂–H₂O–O₂ (CFTSH) and CaO–FeO/Fe₂O₃–Al₂O₃–SiO₂–H₂O–O₂ (CFASH) present in each of the examples. Textural evidence suggests that titanite reaction rims on ilmenite in rocks from Tamil Nadu, Val Strona, and the Bamble Sector originated most likely due to hydration reactions such as clinopyroxene + ilmenite + quartz + H₂O = amphibole + titanite and oxidation reactions such as amphibole + ilmenite + O₂ = titanite + magnetite + quartz + H₂O during amphibolite-facies metamorphism, or, as in the case of the Ötztal Complex, during a subsequent greenschist-facies overprint. Overstepping of these reactions requires fH₂O and fO₂ to be high for titanite formation, which is also in accordance with equilibria involving Al–OH titanite. This study shows that, in addition to P, T, bulk–rock composition and composition of the coexisting fluid, fO₂ and fH₂O also play an important role in the formation of Al-bearing titanite during amphibolite- and greenschist-facies metamorphism.     

OH气辉对重力波响应的模式研究

重力波是中间层大气的重要能量来源,气辉观测为研究中间层重力波特性提供了极好的方法。本文利用最新的 OH 气辉激发机制,建立了一个较完整的光化、动力模式来分析重力波传播对 OH 气辉的影响。结果表明,化学反应速率系数不定性对 Krassovsky 比振幅的影响较小,但淬灭过程的影响必须考虑。Krassovsky 比的振幅和相位均依赖于波周期,其振幅在2.1和10.3之间变化;这表明 OH 气辉亮度的相对变化大于温度的相对变化。一般情况下,重力波引起的温度扰动超前于气辉亮度的变化。与实测资料比较发现,两者变化趋势基本一致,在短周期波时吻合较好。     

混合表面活性剂存在下锰的高灵敏显色反应研究

研究了碱性介质中,Ｍｎ（Ⅱ）被空气氧化生成Ｈ２ＭｎＯ３,然后在Ｈ３ＰＯ４介质中,Ｃｕ（Ⅱ）和阳离子型有机相／水相微乳液（ＣＴＭＡＢ／戊醇／正庚烷／水）的存在下,Ｍｎ（Ⅳ）与二安替比林对乙氧基苯基甲烷（ＤＡｐＥＭ）生成橙色产物,λｍａｘ为４５０ｎｍ,ε＝１．９５×１０５Ｌ·ｍｏｌ－１·ｃｍ－１。Ｍｎ（Ⅱ）的质量浓度在０～３２０μｇ／Ｌ内符合比尔定律。方法用于合金中锰的测定,结果与标准值符合,５次测定结果的ＲＳＤ＜３％。     

A new VLBI observation of an OH maser in a post-asymptotic giant branch star using the European VLBI Network

OH 17.7 − 2.0 is a post-asymptotic giant branch star that is of great interest. The 1612-MHz OH emission from OH 17.7 − 2.0 is characterized by a double-peaked spectrum. Such a line profile has been assumed to represent maser emission from an expanding circumstellar shell. A new VLBI observation of the OH maser in OH 17.7 − 2.0 has been made using the European VLBI Network, and a relative position map of the eight OH maser spots has been obtained. Using the relative position map, it is found that the eight OH maser spots are distributed on an expanding circumstellar shell. The parameters of the expanding circumstellar shell have been obtained.     

A smog chamber for studies of the reactions of terpenes and alkanes with ozone and OH

The design and performance of a smog chamber for the study of photochemical reactions under simulated environmental conditions is described. The chamber is thermostated for aerosol experiments, and it comprises a gas chromatographic sample enrichment system suitable for monitoring hydrocarbons at the ppbv level. By irradiating NO _x /alkane-mixtures rate constants for the reaction of OH radicals with n-alkanes are determined from n-pentane to n-hexadecane to be (k±2)/10^–12 cm³ s^–1=4.29±0.16, 6.2±0.6, 7.52 (reference value), 8.8±0.3, 10.2±0.3, 11.7±0.4, 13.7±0.3, 15.1±0.5, 17.5±0.6, 19.3±0.7, 22.3±1.0, and 25.0±1.3, respectively at 312 K. Rate constants, (k±2)/10^–17 cm³ s^–1, for the reaction of ozone with trans-2-butene (21.2±1.0), cis-3-methylpentene-(2) (47.2±1.7), cyclopentene (62.4±3.5), cyclohexene (7.8±0.5), cycloheptene (28.3±1.5), -pinene (8.6±1.3), and -pinene (1.4±0.2) are determined in the dark at 297 K using cis-2-butene (13.0) as reference standard.     

Introduction to Volume 323 (6) – Proceedings of the Special Colloquium “European Astronomy in the 20th Century” at the Joint European and National Astronomical Meeting (JENAM) for 2001

This issue of AN contains the proceedings of the Special Colloquium “European Astronomy in the 20th Century”, which formed part of the JENAM (2001) conference in Munich, Germany. Subjects covered are the history of γ‐ray and radio astronomy, extragalactic research and compact objects, new media, southern observatories and ESO, as well as some archaeoastronomical questions. Some biographic sketches of individual European astronomers are also given.     

海上围隔进行羟基杀灭赤潮生物的研究

采用强电场电离H2O、O2方法,在分子层次上加工成高浓度羟基自由基(OH.)溶液,喷洒在有赤潮生物的海面上,当海水的羟基质量浓度达到0.68 mg/L时,致死洛氏角刺藻(Chaetoceros lorenzianus)等31种赤潮生物效率达到99.89%,致死细菌、弧菌效率达到100%,致死膝沟藻孢囊、多甲藻孢囊效率达到100%;赤潮生物叶绿素a含量低于检测方法低限值;剩余OH.分解成H2O和O2;尸体将分解成CO2、H2O和微量无机盐。从试验数据表明,OH.是治理赤潮有效可行的绿色新方法。实现了治理赤潮以及加工羟基过程的零污染、零废物排放、零残留物。     

Collisional Quenching of OH Radio Emission from Comet Hale-Bopp

Observations of comets in the 18-cm OH transitions offer a means to probe gas production, kinematics, and OH excitation in comets. We present initial results of OH observations of comet Hale-Bopp obtained with the NRAO 43 m antenna located in Greenbank, WV. Maps of the emission provide strong constraints on the amount of quenching of the inversion of the OH ground state Λ-doublet in the coma. Analysis of the total radio OH flux and maps of its radial brightness distribution indicate a quenched region on the order of ∼500,000 km during March and April 1997. This large value is generally consistent with previous observations of radio OH quenching in lower production rate comets when the high production rate of comet Hale-Bopp is considered. This revised version was published online in July 2006 with corrections to the Cover Date.     

二辉橄榄岩中辉石的"水"的测定

本文中作者采用红外光谱方法对雅鲁藏布江蛇绿岩带拉昂错超基性岩体二辉橄榄岩中的单斜辉石进行了测试研究。结果表明 ,雅鲁藏布江蛇绿岩带拉昂错岩体二辉橄榄岩中的单斜辉石为透辉石 ;该透辉石中含有一定量的结构水 ;并且 ,其高频带相关的结构OH含量是 1 4 6× 1 0 -6。透辉石成分的这种特殊性 (含有结构OH)恰恰是其特殊的高温高压的幔源生成环境的反映。     

致密射电源的快速偏振变化和星际闪烁模型

以类星体０９１７＋６２４中１９８９年５月观测到的ＩＤＶ事件为实例,尝试提出一个４成分模型（１个稳定成分和 ３个闪烁成分）以充分解释在 ６ ｃｍ波长上观测到的偏振变化,包括流量和偏振流量的相关性和反相关性以及它们之间的快速转化．对于 ２０ ｃｍ波长上观测到的偏振变化,３成分模型（１个稳定成分和３个闪烁成分）已足以解释全部现象．文中提出的闪烁模型在解释ＩＤＶ事件的偏振变化方面改进了以前的模型拟合．