河道水体中氢氧稳定同位素组成的微分方程模型

介绍了前人提出并被广泛应用的瑞利分馏模型,指出了其优缺点。针对其不足,在作了一定的假定和简化的前提下,基于瑞利分馏原理和水力学基本定律分别推导了:①静止水体的氢氧稳定同位素组成随时间变化的微分方程模型,揭示了静止水体的同位素组成与时间、分馏系数和蒸发率之间的关系;②河道中运动水体的同位素组成随时间和空间变化的微分方程模型,导出了河道运动水体中稳定同位素组成与分馏系数、流速、流量、蒸发率之间的定量关系。最后通过数学推导论述了上述各模型之间的内在联系。上述模型的建立为定量计算和精确模拟运动水体中氢氧稳定同位素组成的变化提供了确定性的数学基础,也为更客观、更充分的解译水的稳定同位素数据提供了帮助。     

Geochemistry of the Martian Meteorite GRV 99027

GRV 90027 is a Martian lherzolitic shergottites (L-S) containing poikilitic, non-poikilitic, and melted pocket components. GRV 99027 is mainly composed of olive (55 vol%) and pyroxene (37.5 vol%), with minor maskelynite (6 vol%) and chromite (1.5 vol%), and trace whitelockite and troilite, ect. In this paper, the mineralogy and petrology of GRV 99027 are reported; in addition, the geochemical characteristics of the REEs and H isotopes in the GRV 99027 are also further investigated. The ΣREE in GRV 99027 is relatively low; HREEs are enriched in olivine and pyroxene grains; LREEs are enriched in plagioclase with a high positive Eu anomaly. High ΣREE value is found in rare mineral whitlockite (less than 0.2 vol%), LREE≈HREE, and whitlockite has a negative Eu anomaly. The REE distribution patterns of the whole -rock of GRV 99027 is similar to but different from that of other L-S Martian meteorites, indicating that they came from different location of Mars. GRV 99027 has a high δD value. Different water-bearing minerals give different contribution for δD value. The δD of phosphates generally does not correlate with water content, and δD has a weak negative correlation with water content. GRV 99027 can be classified as an L-S Martian meteorite based on mineralogical assemblage patterns, REE distribution patterns, and hydrogen isotope. The isotope data of Sr, Nd, Pb, Os and REE from other L-S Martian meteorites were collected to discuss the formation history of the GRV 99027. Similar to other L-S Martian meteorites, GRV 99027 originated from part of Mar's mantle; during one strong impact event about 4M years ago, the meteorites were ejected from deep mantle into space, and traveled for a different duration in space (indicated by different cosmic exposure time), and captured by the Earth later in different time, ultimately falling on the Antarctica as L-S Martian meteorites.     

氢钟中使用热敏电阻控温的几个问题

对自1991年以来，在上海天文台氢原子钟上使用的热敏电阻控温系统的几个相关问题进行了讨论与分析。该系统的控温精度可达±5％，粗测温度复制性优于±3‰。     

Rotation velocity and neutral hydrogen distribution dependency on magnetic field strength in spiral galaxies

The rotation velocity of a simulated plasma galaxy is compared to the rotation curves of Sc type spiral galaxies. Both show flat rotation curves with velocities of the order of several hundred kilometers per second, modified by E × B instabilities. Maps of the strength and distribution of galactic magnetic fields and neutral hydrogen regions, as-well-as as predictions by particle-in-cell simulations run in the late 1970s, are compared to Effelsberg observations.Agreement between simulation and observation is best when the simulation galaxy masses are identical to the observational masses of spiral galaxies. No dark matter is needed.     

The role of submicrometer aerosols and macromolecules in H2 formation in the titan haze

Previous studies of the photochemistry of small molecules in Titan’s atmosphere found it difficult to have hydrogen atoms removed at a rate sufficient to explain the observed abundance of unsaturated hydrocarbons. One qualitative explanation of the discrepancy nominated catalytic aerosol surface chemistry as an efficient sink of hydrogen atoms, although no quantitative study of this mechanism was attempted. In this paper, we quantify how haze aerosols and macromolecules may efficiently catalyze the formation of hydrogen atoms into H₂. We describe the prompt reaction model for the formation of H₂ on aerosol surfaces and compare this with the catalytic formation of H₂ using negatively charged hydrogenated aromatic macromolecules. We conclude that the PRM is an efficient mechanism for the removal of hydrogen atoms from the atmosphere to form H₂ with a peak formation rate of ∼ 70 cm⁻³ s⁻¹ at 420 km. We also conclude that catalytic H₂ formation via hydrogenated anionic macromolecules is viable but much less productive (a maximum of ∼ 0.1 cm⁻³ s⁻¹ at 210 km) than microphysical aerosols.     

自动调谐器在氢脉泽上的应用结果

本文介绍上海天文台自行研制的氢脉泽调谐［１．２］在我台制造的氢脉泽Ｈ８、Ｈ９、Ｈ１０上的应用．结果表明：氢脉泽自动调谐器有效地改善了氢脉泽的长期稳定度．     

H2S Emissions from a Submerged Pilot‐Scale Fixed Bed Biofilm Reactor

A study was performed in two submerged, pilot‐scale biofilm bioreactors operated under different conditions to determine the relationship between the operating parameters and H₂S emission. H₂S was always detected in the exhaust air at concentrations varying from 1 to 353 ppm_v. The specific aeration rate was the most influencing parameter, with As < 30 kg COD (dissolved oxygen concentrations <4 mg L^?1) increasing noticeably the H₂S production. The periodical removal of the accumulated sludge reduced H₂S emissions by ～14%.     

台湾地区湖泊水库悬浮颗粒有机质之碳、氢、氧、氮、硫元素计量分析

对台湾地区１８个湖泊水库水体中悬浮颗粒有机质之碳，氢，氧，氮，硫和叶绿素α的含量进行了分析，其中ＰＯＯ乃首度以元素分析仪直接测量。结果为，ＰＯＣ，ＰＯＨ，ＰＯＯ，ＰＯＮ，ＰＯＳ含量分别介于１３８－８３７０μｇ／Ｌ，１３．７－９２６．１μｇ／Ｌ，３１－２６２３μｍ／Ｌ，１４－１２６５μｇ／Ｌ，１．９－４９．７μｇ／Ｌ之间，Ｃｈ１．ａ含量则介于０．３１－９６．７５μｇ／Ｌ之间，ＰＯＭ元素间原子数关系为