吉林陨石（H5）的冲击压缩线及其意义

在二级轻气炮动高压装置上运用电探针技术测量了具有H群球粒陨石典型代表性的吉林陨石冲击压缩线。当冲击压力>～70GPa时,吉林陨石发生相变,其高压相零压密度为4.425g/cm~3,硅酸盐部分高压相零压密度为4.068g/cm~3。吉林陨石冲击压缩性质的研究结果与地球形成的星子堆积模型(IAB铁陨石+H群球粒陨石)一致。此外,根据陨石或其类似物的冲击压缩线,用阻抗匹配原理计算了主要类型陨石中重要冲击特征形成的最小碰撞速度,揭示了陨石冲击效应形成的动力学条件与空间环境。     

吉林陨石冲击波压缩和幔岩模型

应用冲击波试验技术研究吉林陨石在冲击压缩期间所出现的相转变。试验雨贡纽点采用最小二乘方去拟合伯奇-默纳汉或默纳汉状态方程分析。文中提出了估计吉林陨石高压态的零压参数方法;试验结果得出,在高压吉林陨石中大部分矿物形成高压相矿物聚合体。它的零压密度为4.395g/cm3,可能含有零压密度6.32g/cm3的钙钛矿结构矿物。计算得出,吉林陨石硅酸盐相零压密度是4.10g/cm3。显然,它与地球模式的下地幔矿物聚合体的零压密度(4.15g/cm3)极一致。由此得出,原始下地幔可能是普通球粒陨石;原始地核是铁陨石小行星。这样,陨石和铁镁硅酸盐中的铁化物岐变,随着地球增长源源不断的提供外核的铁来源。      

吉林陨石的熔融实验研究及其在地球化学中的应用

组成地球的初始物质很可能是IAB铁陨石及H群球粒陨石,非均匀吸积形成地球以后,除由岩浆分异作用使幔中金属-硫化物下沉到原始地核外,在还原条件下还有部分Fe是由橄榄石中的FeO还原为Fe0而提供的并加入于地核内.对于大的陨石母体,由于内部加热或其表面受冲击加热而发生熔融和岩浆分异,导致形成某些铁陨石及无球粒陨石或7型岩石类型的球粒岩石.实验产物中的Fe-Ni-S相可作为判别宇宙球粒的标志之一.      

南丹铁陨石微量元素的微区分布特征

本文用同步辐射X荧光微区扫描法(SRXRFMS)研究了南丹铁陨石中微量元素的微区分布特征。讨论了南丹铁陨石的分类、起源及演化等基本问题。指出南丹铁陨石似分为IAB群较合理,它可能是由具有球粒陨石组成的母源物质受冲击、经局部熔融而形成。     

H型球粒陨石TL灵敏度与冲击相和钾含量的研究

测定了坠落在我国武安、枣阳、信阳等地的10个H型球粒陨石的热释光(TL)灵敏度、自然热释光峰温和峰半高宽温度,同时对它们的K含量进行了测定.将测得的H型球粒陨石的TL灵敏度与它们的钾含量和所属冲击相进行比较.结果表明,H型球粒陨石的TL灵敏度与其钾含量和冲击相之间存在着规律性的关系.      

安徽亳县球粒陨石的铅同位素研究

本文报道了安徽亳县LL4型球粒陨石的全岩、球粒、橄榄石、辉石和陨硫铁的铅同位素比值,以及上述部分样品的铀、钍、铅的含量.由陨石的铅-铅等时线求得的年龄为45.3±0.2亿年,这是安徽陨石母体的形成年龄.而南安徽陨石的内部等时线求得的年龄为44.4±0.2亿年,此年龄暗示着安徽陨石母体在形成后的大约1亿年以前产生过局部或全部的熔融.从安徽陨石的铀-铅一致曲线图解中得到的上交点年龄为45.4±0.2亿年,此与陨石母体形成的铅-铅年龄一致.而下交点的年龄为4亿年,这可能意味着在较近期内安徽陨石又经历了一次热扰动(如热冲击).全岩、球粒和陨硫铁都呈现出过剩的放射性成因铅,这与陨石经受过热事件有关.      

庄河、光明山陨石的岩石矿物学研究

庄河陨石和光明山陨石是两个降落于同一地区的Ｈ５型普通球粒陨石．根据两辉石温度计求出这两个陨石的平衡温度＜ ５００℃；根据镍纹石的带宽与组成关系，获得光明山陨石在其母体中的冷却速率约为 １０－１０℃／Ｍａ，而庄河陨石中普遍出现均一的四方镍纹石表明其冷却速率更低．光明山陨石的冲击变质特征以硅酸盐颗粒破碎为主，其冲击相为Ｓ１；庄河陨石中硅酸盐矿物具明显的波状消光，并存在细小的冲击熔融脉，其冲击相划分为Ｓ２．     

清镇顽火辉石球粒陨石（EH3）的反射光谱特征

本文测定了清镇高铁群3型非平衡顽火辉石球粒陨石(EH3)的可见和近红外反射光谱,发现其反射光谱既不同于显示Ni、Fe金属光谱特征的EH4(Abee)顽火辉石球粒陨石,也不同于显示陨硫铁光谱特征的EH5型和EL6型平衡顽火辉石球粒陨石.清镇陨石独特的反射光谱特征可能是由于其铁纹石粒子表面存在光学厚度的吸积薄膜.吸积薄膜物质很可能是与铁纹石密切共生的陨硅磷镍铁矿,也可能是它与硫化矿物的混合物.在清镇陨石中,含吸积薄膜的铁纹石粒子可能具有很低的氧逸度,它们极易被大气氧化而失去原有的反射光谱特征.文中讨论了EH3、EH4、EH5和EL6型顽火辉石球粒陨石具有不同反射光谱特征的宇宙化学机理.     

亳县陨石中球粒的主量和微量元素的丰度特征及其启示

用仪器中子活化法分析了毫县(LL3-4)陨石中14个球粒的Al,Mg,Mn,Na,V,La,Sm,Au,Sc,Cr,Fe,Co,Ni,Eu,Ir等元素的含量。该陨石的球粒平均成分对Mg和Cl球粒陨石标准化值与其它不平衡普通球粒陨石一致。通过模糊聚类分析和因子分析讨论了元素间的相关关系。这些球粒的原始物质组分至少包括亲铁元素,难熔和中等难熔亲石元素以及中等挥发性元素等,这也与其它不平衡普通球粒陨石大体一致。因此,普通球粒陨石各化学群的差别主要是由基质造成的。      

宁强陨石（CV3）稀有气体的研究

宁强陨石的岩石学、矿物学及化学组成的研究表明,宁强陨石属于异常的CV3碳质球粒陨石,稀有气体和宇宙射线暴露年龄的测定结果与岩石学及化学组成的研究结果是一致的,宁强陨石的宇宙射线暴露年龄为42.2Ma,在CV3球粒陨石中是最高的,U/Th-4He及40K-40Ar气体保存年龄分别为4170±160Ma和4260±70Ma,这与碳质球粒陨石的气体保存年龄为4200Ma是一致的.     

Cosmic ray detection on the Foton-M2 satellite by a track etch detector stack

In the frame of the European Space Agency (ESA) project called “Biology and Physics in Space”, the returning satellite, Foton-M2, carried an open-to-space exposure platform outside of the satellite body, called as BIOPAN-5, loaded with exo-biological experiments and facilities for radiation dosimetry (RADO). One of the RADO experiments was dedicated to the detection of the primary galactic cosmic rays (GCR) and secondary neutrons by a track etch detector stack. The daily absorbed dose (D) and dose equivalent (H) were calculated from the experimental LET spectra (LET > 10 keV/μm). Under a shielding of ∼2.8 g/cm² the averaged H was found to be 658 ± 8 μSv/d, with a quality factor (Q) of 6.2 ± 1.2. The LET spectra showed a local peak at ∼105 keV/μm suggesting that the majority of tracks were created by trapped protons as it has been predicted by calculations. The low LET dose of the cosmic radiation was determined by 4 TLD stacks, and the total dose was found to be 795 ± 14 μSv/d.     

量热技术在铷光谱灯中的应用研究

铷光谱灯是铷原子钟的核心部件。在铷光谱灯的研制中差式扫描量热技术（DSC）是不可或缺的测量手段和研究方法之一。本文通过对长期老化跟踪测量的铷量消耗数据拟合,得到了目前使用的铷灯的铷量消耗模型。分析结果显示：铷与灯泡内的杂质反应消耗了约37.5μg金属铷,铷的消耗率稳定在0.23μg/hr,预计10年使用寿命期内铷的消耗量约106μg。铷熔融曲线的熔点和纯度测量结果显示：铷的熔点和纯度在老化开始前2个月变化明显,具有较好的相关性。老化6个月以后铷的熔点和纯度从老化开始前的36℃和99.56％提高到39.5℃和99.84％,并趋于稳定,其变化趋势与老化初期铷量的消耗规律较好地吻合。     

日全食期间中间层大气臭氧光化过程试验

利用包括活O_x、HO_x、和NO_x等成份在内的一维时变光化模式,研究了日全食时上中层大气臭氧和O₂(1△g)的变化特性,并通过与观测资料的比较进行了光化模式的试验.结果表明,日全食时太阳辐照变化对1.27μm气晖影响的高度比曙暮期间明显偏低,利用1.27μm气晖光度计测量大气臭氧的高度范围约为52-67km.1997年3月9日漠河日全食时测量的大气臭氧含量变化幅度为50％.这与考虑O_x、HO_x、和NO_x等成份的光化模式理论模拟结果基本一致.它表明在52-67km高度范围不存在臭氧亏损现象.      

Verification of shielding effect by the water-filled materials for space radiation in the International Space Station using passive dosimeters

The dose reduction effects for space radiation by installation of water shielding material (“protective curtain”) of a stack board consisting of the hygienic wipes and towels have been experimentally evaluated in the International Space Station by using passive dosimeters. The averaged water thickness of the protective curtain was 6.3 g/cm². The passive dosimeters consisted of a combination of thermoluminescent detectors (TLDs) and plastic nuclear track detectors (PNTDs). Totally 12 passive dosimeter packages were installed in the Russian Service Module during late 2010. Half of the packages were located at the protective curtain surface and the other half were at the crew cabin wall behind or aside the protective curtain. The mean absorbed dose and dose equivalent rates are measured to be 327 μGy/day and 821 μSv/day for the unprotected packages and 224 μGy/day and 575 μSv/day for the protected packages, respectively. The observed dose reduction rate with protective curtain was found to be 37 ± 7% in dose equivalent, which was consistent with the calculation in the spherical water phantom by PHITS. The contributions due to low and high LET particles were found to be comparable in observed dose reduction rate. The protective curtain would be effective shielding material for not only trapped particles (several 10 MeV) but also for low energy galactic cosmic rays (several 100 MeV/n). The properly utilized protective curtain will effectively reduce the radiation dose for crew living in space station and prolong long-term mission in the future.     

Variability of organic material in surface horizons of the hyper-arid Mars-like soils of the Atacama Desert

The objective of this work was to investigate the variability of surface organic carbon within the hyper-arid Yungay region of the Atacama Desert. The fraction of Labile Organic Carbon (LOC) in these samples varied from 2 to 73 μg per gram of soil with a bi-modal distribution with average content of 17 ± 9 μg LOC and 69 ± 3 μg LOC for “low” and “high” samples, respectively. Interestingly, there was no relation between organic levels and geomorphologic shapes. While organics are deposited and distributed in these soils via eolic processes, it is suggested that fog is the dynamic mechanism that is responsible for the variability and peaks in organic carbon throughout the area, where a “high” LOC content sample could be indicative of a biological process. It was determined that there was no significant difference between topological feature or geographical position within the hyper-arid samples and LOC. This very curious result has implications for the investigation of run-off gullies on the planet Mars as our work suggests a need for careful consideration of the expectation of increases in concentrations of organic materials associated with following aqueous altered topology.     

Mapping of hydrothermally altered rocks using airborne multispectral scanner data,Marysvale, Utah,mining district

Multispectral data covering an area near Marysvale, Utah, collected with the airborne National Aeronautics and Space Administration (NASA) 24-channel Bendix multispectral scanner, were analyzed to detect areas of hydrothermally altered, potentially mineralized rocks. Spectral bands were selected for analysis that approximate those of the Landsat 4 Thematic Mapper and which are diagnostic of the presence of hydrothermally derived products. Hydrothermally altered rocks, particularly volcanic rocks affected by solutions rich in sulfuric acid, are commonly characterized by concentrations of argillic minerals such as alunite and kaolinite. These minerals are important for identifying hydrothermally altered rocks in multispectral images because they have intense absorption bands centered near a wavelength of 2.2 μm. Unaltered volcanic rocks commonly do not contain these minerals and hence do not have the absorption bands.A color-composite image was constructed using the following spectral band ratios: 1.6μm/2.2μm, 1.6μm/0.48μm, and 0.67μm/1.0μm. The particular bands were chosen to emphasize the spectral contrasts that exist for argillic versus non-argillic rocks, limonitic versus nonlimonitic rocks, and rocks versus vegetation, respectively. The color-ratio composite successfully distinguished most types of altered rocks from unaltered rocks. Some previously unrecognized areas of hydrothermal alteration were mapped. The altered rocks included those having high alunite and/or kaolinite content, siliceous rocks containing some kaolinite, and ash-fall tuffs containing zeolitic minerals. The color-ratio-composite image allowed further division of these rocks into limonitic and nonlimonitic phases. The image did not allow separation of highly siliceous or hematitically altered rocks containing no clays or alunite from unaltered rocks.A color-coded density slice image of the 1.6μm/2.2μm band ratio allowed further discrimination among the altered units. Areas containing zeolites and some ash-fall tuffs containing montmorillonite were readily recognized on the color-coded density slice as having less intense 2.2-μm absorption than areas of highly altered rocks. The areas of most intense absorption, as depicted in the color-coded density slice, are dominated by highly altered rocks containing large amounts of alunite and kaolinite. These areas form an annulus, approximately 10 km in diameter, which surrounds a quartz monzonite intrusive body of Miocene age. The patterns of most intense alteration are interpreted as the remnants of paleohydrothermal convective cells set into motion during the emplacement of the central intrusive body.     

哈雷彗星的JHK光度和1.3—2.6微米分光观测结果及分析

本文给出哈雷彗星在1986年3月25日至4月2日之间JHK波段测光和1.3—2.6微米分光观测结果。测光结果表明,3月22日彗星爆发在近红外波段也造成了明显的光变,但恢复正常光度的时间要滞后一些,且光变较之可见光波段要平缓.并指出在爆发期间,彗星除光变外尚有色变。分光观测到彗星在1.4、1.9微米的水发射线和位于2.6微米之外的可能的OH发射线。      

Influence of solar-geomagnetic disturbances on SABER measurements of 4.3 μm emission and the retrieval of kinetic temperature and carbon dioxide

Thermospheric infrared radiance at 4.3 μm is susceptible to the influence of solar-geomagnetic disturbances. Ionization processes followed by ion-neutral chemical reactions lead to vibrationally excited NO⁺ (i.e., NO⁺(v)) and subsequent 4.3 μm emission in the ionospheric E-region. Large enhancements of nighttime 4.3 μm emission were observed by the TIMED/SABER instrument during the April 2002 and October–November 2003 solar storms. Global measurements of infrared 4.3 μm emission provide an excellent proxy to observe the nighttime E-region response to auroral dosing and to conduct a detailed study of E-region ion-neutral chemistry and energy transfer mechanisms. Furthermore, we find that photoionization processes followed by ion-neutral reactions during quiescent, daytime conditions increase the NO⁺ concentration enough to introduce biases in the TIMED/SABER operational processing of kinetic temperature and CO₂ data, with the largest effect at summer solstice. In this paper, we discuss solar storm enhancements of 4.3 μm emission observed from SABER and assess the impact of NO⁺(v) 4.3 μm emission on quiescent, daytime retrievals of Tk/CO₂ from the SABER instrument.     

Soil carbon distribution and site characteristics in hyper-arid soils of the Atacama Desert: A site with Mars-like soils

The soil carbon content and its relation to site characteristics are important in evaluating current local, regional, and global soil C storage and projecting future variations in response to climate change. In this study we analyzed the concentration of organic and inorganic carbon and their relationship with in situ climatic and geological characteristics in 485 samples of surface soil and 17 pits from the hyper-arid area and 51 samples with 2 pits from the arid–semiarid region from the Atacama Desert located in Peru and Chile. The soil organic carbon (SOC) in hyperarid soils ranged from 1.8 to 50.9 μg C per g of soil for the 0–0.1 m profile and from 1.8 to 125.2 μg C per g of soil for the 0–1 m profile. The analysis of climatic (temperature and precipitation), elevation, and some geologic characteristics (landforms) associated with hyper-arid soils explained partially the SOC variability. On the other hand, soil inorganic carbon (SIC) contents, in the form of carbonates, ranged from 200 to 1500 μg C per g of soil for the 0–0.1 m profile and from 200 to 3000 μg C per g of soil for the 0–1.0 m profile in the driest area. The largest accumulations of organic and inorganic carbon were found near to arid–semiarid areas. In addition, the elemental carbon concentrations show that the presence of other forms of inorganic carbon (e.g. graphite, etc.) was negligible in these hyperarid soils. Overall, the top 1 m soil layer of hyperarid lands contains ∼11.6 Tg of organic carbon and 344.6 Tg of carbonate carbon. The total stored carbon was 30.8-fold the organic carbon alone. To our knowledge, this is the first study evaluating the total budget carbon on the surface and shallow subsurface on ∼160,000 km² of hyperarid soils.