黑洞候选体X射线双星Cyg X-1长期谱变化的研究

利用Rossi X-ray Timing Explorer(RXTE)卫星从1996年1月5日到2005年5月1日的all-sky monitor(ASM,1.5—12KeV)资料,详细分析了黑洞候选体X射线双星Cyg X-1在A-band(1.5—3KeV),B-band(3—5KeV)和C-band(5—12KeV)三个能段上光子计数率与谱线硬度比HR2(5——12KeV/3——5KeV)的相关性.利用1天时标的ASM资料研究发现,(1)Cyg X-1处于软态时,在A-band上光子计数率与硬度比HR2呈现反相关性,而在B-band和C-band上呈现正相关性.当该天体处于硬态时,在A、B、C三个能段上光子计数率与硬度比HR2都是反相关的.(2)Cyg X-1处于硬态和软态时,硬度比HR2与HR1都是正相关的.此外,还分析了ASM上"Dwell by Dwell"资料,得到了十分有趣的结果,即:(1)MJD=52600—52760期间(此时Cyg X-1处于硬态),A-band和B-band上的光子计数率与HR2是反相关性的,而在C-band上却呈现出较强的正相关性.(2)硬态时,硬度比HR2与HR1存在明显的反相关性.

Support effect of zinc tin oxide on gold catalyst for CO oxidation reaction

Nanostructured gold catalyst supported on metal oxide is highly active for the CO oxidation reac‐tion. In this work, a new type of oxide support, zinc tin oxide, has been used to deposit 0.7 wt%Au via a deposition‐precipitation method. The textural properties of Zn2SnO4 support have been tuned by varying the molar ratio between base （N2H4＆#183;H2O） and metal ion （Zn2＋） to be 4/1, 8/1 and 16/1. The catalytic tests for CO oxidation reaction revealed that the reactivity on Au‐Zn2SnO4 with N2H4＆#183;H2O/Zn2＋ = 8/1 was the highest, while the reactivity on Au‐Zn2SnO4 with N2H4＆#183;H2O/Zn2＋ =16/1 was almost identical to that of the pure support. Both fresh and used catalysts have been characterized by multiple techniques including nitrogen adsorption‐desorption, X‐ray diffraction, transmission electron microscopy, high‐angle annular dark‐field scanning transmission electron microscopy, X‐ray photoelectron spectroscopy, X‐ray adsorption fine structure, and tempera‐ture‐programmed reduction by hydrogen. These demonstrated that the textural properties, espe‐cially pore volume and pore size distribution, of Zn2SnO4 play crucial roles in the averaged size of gold nanoparticles, and thus determine the catalytic activity of Au‐Zn2SnO4 for CO oxidation.

Synthesis and Crystal Structure of a Novel Polymer Copper(Ⅱ) Complex

A novel chain complex was synthesized and its crystal structure has been deter- mined by X-ray diffraction technique. It was found that the local coordination geometry around Cu(Ⅱ) is a distorted tetrahedron and C14H9CuNO3CH3OH is bridged by the carboxylate oxygen atom to form an infinite one-dimensional linear chain. The hydrogen bond exists between O(1) and solvate molecule O(4). The crystal belongs to monoclinic, space group P21 with a = 9.6650(19), b = 7.1280(14), c = 9.925(2) ? b = 98.39(3)? V = 676.4(2) 3, Z = 2, F(000) = 342 and m(MoK? = 1.629 mm-1 .

In situ studies on ceria promoted cobalt oxide for CO oxidation

In situ studies of catalysts play valuable roles in observing phase transformation, understanding the corresponding surface chemistry and the mechanism of the reaction. In this paper, ceria promoted cobalt oxide was prepared by the calcination method and investigated for the CO oxidation. The microstructure and morphology of CeO2-Co3O4 were investigated by the Scanning Electron Microscope, High-resolution transmission electron microscopy, Raman and X-ray photoelectron spectroscopy characterization. The effect of CeO2 doping on Co3O4 for CO oxidation was characterized by in situ X-ray Diffraction (in situ XRD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). In situ XRD was carried out under H2 atmosphere to evaluate the redox property of catalysts. The results indicated that the ceria doping can enhance the reducibility of Co2+ and promote the Co3+-Co2+-Co3+ cycle, owing to the oxygen replenish property of CeO2. Furthermore, adsorbed carbonate species on the surface of CeO2-Co3O4 were investigated by in situ-DRIFTS experiment. It was turned out that carbonate species on ceria promoted cobalt oxide catalysts showed different IR peaks compared with pure cobalt oxide. The carbonate species on ceria promoted catalyst are more active, and similar to free state carbonate species with weak bonding to catalyst surface, which can effectively inhibit catalyst inactivation. This study revealed the mechanism of ceria promoting CO oxidation over cobalt oxide, which will provide theoretical support for the design of efficient CO oxidation catalysts.

干姜挥发油β-环糊精包合物的实验研究

目的将干姜挥发油制成β-环糊精(β-CD)包合物并对其质量进行分析验证。方法采用正交试验探讨β-环糊精(β-CD)包合工艺,应用TLC、UV和X-射线衍射分析对包合物进行质量考察。结果包合物确已形成一种新的物相,包合前后挥发油组成无变化。结论β-环糊精(β-CD)包合技术可以使干姜挥发油固化,从而减少挥发油的损失,提高生物利用度。

直接金属氧化法制备SiC_p/Al_2O_3-Al复合材料的显微结构及工艺因素的研究

在低成本的前提下 ,利用直接金属氧化法 (DIMOX)制备了SiC颗粒增强Al2 O3-Al基复合材料 ,并详细叙述了此种方法的工艺过程。借助于X—射线衍射 (XRD)和扫描电镜 (SEM)对该种复合材料的微观结构进行了观察 ,分析了SiO2 层、合金成分和温度制度对复合材料性能的影响。结果表明 ,此种复合材料结构致密且渗透完全 ,微观结构由三种相互穿插相组成 :SiC预制体、连续的Al2 O3基体 ,呈网状结构分布的未被氧化的残余Al。合金成分及烧成制度是此工艺过程中的最重要的工艺参数。

预膜剂成膜厚度的研究

采用扫描电镜(SEM)结合X-射线能谱仪(EDS)分析了预膜剂在碳钢表面成膜的成分及形貌,特别是对成膜厚度进行了细致的研究,并采用适当的检测器及特殊的制样方法,得到了真正的膜厚度,并考察了预膜剂浓度对膜厚度及腐蚀速率的影响。

ACNH_2—H_2C_2O_4二元系的DSC测定

本文用DSC方法测定了ACNH_2—H_2C_2O_4二元系的相图,实验发现该二元系有一个新的相化合物ACNH_2·H_2C_2O_4生成,并用X—射线衍射数据进一步证实了该化合物的存在,它和ACNH_2的低共熔点为50.0℃、30％H_2C_2O_4、70％ACNH_2,它和H_2C_2O_4的低共熔点为112.0℃、76.0％H_2C_2O_4、24.0％ACNH_2。

Microstructure and hydrogen storage properties of as-cast and rapidly solidified Ti-rich Ti-V alloys

The goal of the present work was to optimize the phase-structural composition and microstructure of binary Ti0.8-0.9V0.2-0.1 alloys with respect to their hydrogen sorption properties. Application of these alloys is for hydrogen absorption from gaseous mixtures containing substantial amounts of carbon monoxide （CO） at high temperatures. Irrespective of alloy composition, both α（HCP） and β（BCC） phases in Ti0.8-0.9V0.2-0.1 formed single phase FCC hydrides upon hydrogenation in pure H2. An in situ synchrotron X-ray diffraction study showed that only the β-phase transformed to the corresponding hydride when the alloy was hydrogenated in a mixture of H2＋10%CO. Rapid solidification （RS） of the alloy resulted in refined grain sizes both in the Ti0.8V0.2 and Ti0.9V0.1 alloys. Furthermore, RS was found to increase the β-phase fraction in Ti0.9V0.1, being twice larger than that of the as-cast alloy. Ti0.9V0.1 had a platelike microstructure as observed by scanning electron microscopy （SEM）, the plates were about 300 nm thick. The microstructure refinement resulted in a faster kinetics of H desorption as observed by temperature desorption spectroscopy （TDS）.

Phase, magnetism and thermal conductivity of glass ceramics from iron ore tailings

In order to develop the applications of ore tailings, the glass ceramics were prepared by using a conventional melting-quenching-sintering process. The phase component, microstructures, magnetic properties and thermal conductivities of the prepared glass ceramics were investigated by using X-ray diffractometer, scanning electron microscopy, vibrating sample magnetometer and thermophysical properties tester, respectively. The results show that orthorhombic olivine-type phase and triclinic sunstone-type phase formed when the glass was annealed at 700 oC, the concentration of olivine-type and sunstone-type phases decreased, the spinel-type cubic phase occurred and the amount increased when the annealing temperatures increased. The magnetic properties from the cubic spinel ferrites were detected in the glass ceramics, and the related saturation magnetization increased with the annealing temperature increasing. The porous glass ceramics with magnetic property showed much lower thermal conductivity, compared with the non-magnetic porous glass-ceramic and the dense glass-ceramics.

Crystal structures and elastic properties of Ti(Cu,Pt)2 and Ti(Cu,Pt)3 phases

This paper focused on the crystal structures of two new ternary phases,Ti(Cu,Pt)2 and Ti(Cu,Pt)3,which were studied by X-ray powder diffraction data using Rietveld method.Electron probe microanalysis was used for sample composition examination.Elastic properties of these phases were further measured by nano-indentation,and meanwhile calculated with first-principle(FP)calculations.It is found that the crystal structure of Ti(Cu,Pt)2 is of orthorhombic cell space group Amm2(No.38)with structural prototype of VAu2.The resolved structure of Ti(Cu,Pt)3 is of tetragonal Al Pt3 type,belonging to the space group P4/mmm(No.123).The nano-indentation measurement and FP calculations show that the elastic modulus of Ti(Cu,Pt)2 increases firstly then decreases with Pt content,whereas that of Ti(Cu,Pt)3almost linearly increases with Pt content.

Laboratory study on geotechnical characteristics of marine coral clay

The hydraulic reclamation coral clay is a new type of clay,formed during the sorting process of coral island reef reclamation.The foundation of the hydraulic reclamation coral reef consists of coral sand,silt,and clay.The part of the particles with particle size less than 0.075 mm contain more than 50%forms clay.As a new type of clay,the geotechnical properties were rarely reported in previous studies.In this paper,the physical and mechanical properties,microstructure and mineral composition were comprehensively researched by a series of laboratory tests.The results show that coral clay is a low liquid limit clay with high pore ratio and high saturation.From the aspect of mineral compositions,the coral clay studied consists of calcite and aragonite,while the chemical composition of it is calcium carbonate.The void ratio has a significant effect on the compressive properties of coral clay.With the increase of the void ratio,the compression coefficient a_(1-2) and compression index C_(c) gradually increase,and the compression modulus Es gradually decreases.The undrained stress−strain curve of coral clay shows a strain-softening behavior,and the peak strength and residual strength are positively linear correlated with confining pressure.

Reservoir space of the Es_3~3–Es_4~1shale in Dongying sag

The Es3/3-Es1/4 shales in Dongying sag are source rocks with large reserves of shale oil and gas. For the iden- tification of development characteristics and geological significance of the reservoir space, FM1 logging, core observation, thin section analysis, X-ray diffraction, fluorescence microscopy, scanning electron microscopy, mercury porosimetry, low-temperature nitrogen adsorption, atomic force microscopy, and conventional physical property testing were used to study the petrology and reservoir space of the Es3/3-Es1/4 shale in Dongying sag. The results suggest that the shale is rich in carbonate minerals. Phanero- crystalline stratiform and lamellar argillaceous limestone and calcareous claystone are the oil- and gas-bearing lithofacies. The oil in the micropores is mainly present as membranes and clots. The shale reservoir space has a network structure with veins, carbonate and clay minerals, and micropores among pyrite and the matrix. The results provide the geological framework for future shale oil and gas explora- tion in Dongying sag.

Near Ambient Pressure Adsorption of Nickel Carbonyl Contaminated CO on Cu(111) Surface

Formation of volatile nickel carbonyls with CO in catalytic reaction is one of the mechanisms of catalyst deactivation. CO is one of the most popular probe molecules to study the surface properties in model catalysis. Under ultra-high vacuum (UHV) conditions, the problem of nickel carbonyl impurity almost does not exist in the case that a high purity of CO is used directly. While in the near ambient pressure (NAP) range, nickel carbonyl is easily found on the surface by passing through the Ni containing tubes. Here, the NAP techniques such as NAP-X-ray photoelectron spectroscopy and NAP-scanning tunneling microscopy are used to study the adsorption of nickel carbonyl contaminated CO gas on Cu(111) surface in UHV and NAP conditions. By controlling the pressure of contaminated CO, the Ni-Cu bimetallic catalyst can form on Cu(111) surface. Furthermore, we investigate the process of CO adsorption and dissociation on the formed Ni-Cu bi-metal surface, and several high-pressure phases of CO structures are reported. This work contributes to understanding the interaction of nickel carbonyl with Cu(111) at room temperature, and reminds the consideration of CO molecules contaminated by nickel carbonyl especially in the NAP range study.

Clean transfer of graphene on Pt foils mediated by a carbon monoxide intercalation process

Noble metals such as Pt are a perfect substrate for the catalytic growth of monolayer graphene. However, the requirements of the subsequent transfer process are not compatible with the traditional etching method. In this work, we find that the interaction of graphene with Pt foil can be weakened through the intercalation of carbon monoxide （CO） under ambient pressure. This intercalation process occurs on both hexagonal-shape graphene islands and irregular graphene patches on changing the CO partial pressure from 0 to 0.6 MPa, as observed by scanning electron microscopy （SEM）, Raman spectroscopy and X-ray photoemission spectroscopy. We demonstrate that, on a practical timescale, the intercalation ratio is proportional to the partial pressure of CO. Furthermore, we develop a clean transfer method of CO-intercalated graphene with water as a peeling agent. We show that this method enables the transfer of tens of micrometer-scale graphene patches onto SiO2/Si, which are free from metal or oxide particle contamination. This transfer method should be a significant step towards the dean transfer of graphene, as well as the recydable use of noble metal substrates.

One-dimensional lanthanide complexes bridged by nitronyl nitroxide radical ligands with non-chelating nitrogen donors: Structure and magnetic characterization

A series of new lanthanide-radical complexes [{Ln（hfac）3}2（NITPhlM）2] （Ln = Nd （1）, Eu （2）, Tb （3）, Er （4）; hfac = hexafluoroacetylacetonate; NITPhlM = 2-[4-（1-imidazole）phenyl]-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide） have been prepared and characterized. Single crystal X-ray diffraction analyses reveal that these complexes are isostructural with one-dimensional chain structures. These consist in Ln（hfac）3 units bridged by the paramagnetic ligands by the means of coor- dination of their nitronyl nitroxide groups and imidazole rings. Interestingly, each Ln ion is either bound to two nitronyl ni- troxide groups or to two imidazole units, and the different Ln centers alternate along the chain. Magnetic studies show that complex 3 exhibits a single-chain magnet behavior.

One-step hydrothermal synthesis of hierarchical Ag/Bi_2WO_6 composites: In situ growth monitoring and photocatalytic activity studies

Hierarchical Ag/Bi2WO6 nanomaterials were prepared by a facile one-step hydrothermal method in mixed acetic acid and ethylene glycol (EG) medium. EG is employed as mild reducing agent for the formation of metallic Ag from Ag+ precursors. In situ energy dispersive X-ray diffraction (EDXRD) monitoring showed that the hydrothermal formation kinetics of Bi2WO6 in the presence of EG was significantly slowed down due to its very high viscosity. The photocatalytic activities of Ag/Bi2WO6 composites were evaluated by the photodegradation of methylene blue (MB) under visible light irradiation. The photocatalytic activity of Bi2WO6 is strongly influenced by the Ag loading. The enhanced catalytic activity of the composites is based on the cooperative effects of plasmon absorption band and separation of photogenerated electron-hole pairs.

Distinct phase transitions and dielectric anomalies in two 4-methylanilinium salts

Solid-state phase transitions of 4-methylanilinium perchlorate （4-CH3C6H4NH3.C104, 1） and tetrafluoroborate （4-CH3C6H4- NH3-BF4, 2） were investigated with variable-temperature X-ray single-crystal structure analysis and thermal studies. Both 1 and 2 undergo first-order phase transitions and exhibit distinct dielectric anomalies at 385 and 247 K, respectively.

One-step preparation of vinyl-functionalized material surfaces:a versatile platform for surface modification

A simple approach has been developed to functionalize various substrates, such as gold and polyvinylchloride, with dopamine methacrylamide—a molecule with adhesive properties that mimic those of mussels—to produce a versatile and general platform for subsequent surface modification. With active double bonds on the surface, various polymers, such as poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide(PMEDSAH) and poly(N-vinylpyrrolidone)(PVP), can be grafted by conventional radical polymerization. Double bond surface functionalization and subsequent polymer grafting have been verified by static water contact angle, Fourier transform infrared–attenuated total reflectance(FTIR-ATR) spectroscopy and X-ray photoelectron spectroscopy(XPS) measurements. Protein adsorption assays showed that the polymermodified substrates have good protein-resistant properties. Considering the advantages of facility, versatility and substrate- independence, this method should be useful in designing functional interfaces for bioengineering applications.