伽马射线谱仪探测月球表面元素的分布——以“嫦娥一号”伽马射线谱仪为例

Apollo和Lunar Prospector(LP) 携带的伽马射线谱仪探测了月球表面的氧（O）、硅（Si）、铝（Al）、铁（Fe）、钛（Ti）、钙（Ca）、钾（K）、镁（Mg）、钍（Th）和铀（U）等10种元素的全球分布，对于了解月球的形成与演化有重要的意义。在我国首颗月球探测卫星“嫦娥一号”上搭载了伽马射线谱仪将进一步探测月球表面14种元素的分布特征。本论文的选题紧密结合“嫦娥一号”伽马射线谱仪数据处理和科学反演工作的工程需求，系统研究了伽马射线谱仪探测数据的处理流程和反演方法，并利用LP的数据开展了月球元素、岩石类型及其分布特征的反演工作，为嫦娥一号卫星伽马射线谱仪的数据处理和反演奠定了技术基础。论文主要包括如下几个方面的内容： （1）概述了伽马射线谱仪探测月球表面元素的发展历程，特别是阐述了伽马射线产生的机理和伽马射线谱仪元素探测的原理； （2）讨论了伽马射线谱仪数据反演及其模型，以及在“嫦娥一号”伽马射线谱仪数据反演中的应用； （3）阐述了“嫦娥一号”伽马射线谱仪性能指标，数据处理流程，地面验证实验（模拟月壤的研制及其试验）和初步的探测成果； （4）以LP伽马射线谱仪探测数据为例，讨论了伽马射线谱仪探测数据科学反演工作，阐述了全球Th的分布特征以及月球化学不均一性的相关性；用LP探测数据首次划分出月球岩石类型的分布，探讨了月球演化对岩石类型分布特征的影响。

Experimental investigation of an unstable ring resonator with 90-deg beam rotation for a chemical oxygen iodine laser

We report the experimental results of an unstable ring resonator with 90-deg beam rotation for a kilowatt class chemical oxygen iodine laser (COIL). The distributions of near-field phase and far-field intensity were measured. A beam quality of 1.6 was achieved when the COIL average output power was approximately 5 kW. (C) 1999 Optical Society of America.

海洛因成瘾脑灰质密度和结构网络研究

Behavioral and functional imaging studies consistently show that heroin abuse leads to various cognitive impairments, while brain structural changes associated with heroin use remain poorly understood. In the current study, we used voxel-based morphology (VBM), a method sensitive to structural changes of the brain, to investigate the gray concentration in MRI structure images of heroin addicts. Results show that the concentration of the temporal cortex and frontal cortex of heroin users significantly decreased as compared to age/education matched normal controls. Further analysis revealed that this brain structure change was detectable only in the users who had used heroin more than 5 year, but not in the remaining users. These results converge to the abnormality of the brain structure in heroin users and this abnormality is clearly associated with duration of drug use. We then analyzed the large-scale brain structure network in the heroin addicts. As compared to the normal controls, there was significant difference in interregional correlation between the temporal cortex, hippocampus, thalamus, and frontal cortex. Importantly, two major indices of the small-world properties, Clustering coefficient(Cp) and shortest path length (Lp), which are thought to reflect the local specialty and global integrity, were marginal-significantly larger than the normal controls, especially for Lp. These results suggest that chronic use of heroin results in the reorganization of the brain system. Taken together, this thesis has provided compelling evidence for brain structure impairments in chronic heroin users and further characterized the large-scale brain structure network in the same population.

Catalytic oxidation of cyclohexane to cyclohexanol and cyclohexanone over Co3O4 nanocrystals with molecular oxygen

Co3O4 nanocrystals with average particle sizes of 30 and 50 run were synthesized using cobalt nitrate as precursor, and were characterized by X-ray diffraction (XRD), nitrogen adsorption, transmission electron microscopy (TEM), and Fourier transform infrared (FT-IR) spectroscopy. Catalytic oxidation of cyclohexane with molecular oxygen was studied over Co3O4 nanocrystals. These catalysts showed obviously higher activities as compared to Co3O4 prepared by the conventional methods, Co3O4/Al2O3, or homogeneous cobalt catalyst under comparable reaction conditions. The 89.1% selectivity to cyclohexanol and cyclohexanone at 7.6% conversion of cyclohexane was realized over 50 nm sized Co3O4 nanocrystals at 393 K for 6 h. (c) 2005 Elsevier B.V. All rights reserved.

Synthesis of FeCoMnAPO-5 molecular sieve and catalytic activity in cyclohexane oxidation by oxygen

A new FeCoMnAPO-5 with AFI structure was synthesized under hydrothermal conditions and characterized by XRD, FT-IR, X-ray fluorescence, nitrogen adsorption and SEM. The oxidation of cyclohexane with molecular oxygen was studied over the catalyst at 403 K. It show d higher activity compared to FeAPO-5, CoAPO-5 and MnAPO-5. The FeCoMnAPO-5 catalyst was recycled twice without loss of activity or selectivity.

Liquid phase oxidation of toluene to benzaldehyde with molecular oxygen over copper-based heterogeneous catalysts

We conducted the liquid phase oxidation of toluene with molecular oxygen over heterogeneous catalysts of copper-based binary metal oxides. Among the copper-based binary metal oxides, iron-copper binary oxide (Fe/Cu = 0.3 atomic ratio) was found to be the best catalyst. In the presence of pyridine, overoxidation of benzaldehyde to benzoic acid was partially prevented. As a result, highly selective formation of benzaldehyde (86% selectivity) was observed after 2 h of reaction (7% conversion of toluene) at 463 K and 1.0 MPa of oxygen atmosphere in the presence of pyridine. These catalytic performances were similar or better than those in the gas phase oxidation of toluene at reaction temperatures higher than 473 K and under 0.5-2.5 MPa. It was suggested from competitive adsorption measurements that pyridine could reduce the adsorption of benzaldehyde. At a long reaction time of 4 It, the conversion increased to 25% and benzoic acid became the predominant reaction product (72% selectivity) in the absence of pyridine. The yield of benzoic acid was higher than that in the Snia-Viscosa process, which requires corrosive halogen ions and acidic solvents in the homogeneous reaction media. The catalyst was easily recycled by simple filtration and reusable after washing and drying.