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The microscopic differences in characteristics and formation mechanism of shale oil reservoirs in the upper and lower sweet spot sections of the Lucaogou Formation in the Jimsar Depression, which has been identified as a national shale oil demonstration area in China, are still unclear. In this study, the characteristics and the main controlling factors of reservoir differences in different sweet spots of Lucaogou Formation were specified based on core observation, thin-section observation, X-ray diffraction, Rock-Eval, microscopic fluorescence of hydrocarbon inclusions, and temperature measurement of saline inclusions. Results show that the Lucaogou Formation mainly develops dissolution and primary intergranular pores. The dissolution transformation leads to obvious differences between the upper and lower sweet spots. Specifically, the upper sweet spot section mainly develops primary intergranular pores and partially develops dissolution pores; the lower sweet spot section mainly develops dissolution pores, including intergranular, intragrain, and intergranular pores. Geochemical data such as inclusions indicate that hydrocarbon generation began in the Triassic, and a large number of hydrocarbons were charged in the Middle-Late Jurassic-Early Cretaceous. As the key fluid that triggers reservoir dissolution modification, it is mainly derived from organic acids generated by thermal evolution of source rocks within shale formations. The scale and quality of source rocks in the lower sweet spot are better than those in the upper sweet spot. The former has stronger hydrocarbon generation potential, which lays a foundation for the scale difference of organic acid output in the upper and lower sweet spots. At the same time, the source rocks in the lower sweet spot are more mature due to magmatic-hydrothermal upwelling. This condition accelerates the release of organic acids from source rocks, which results in the scale difference of dissolution effects in the upper and lower sweet spots. [ABSTRACT FROM AUTHOR]

A series of air-stable zinc complexes ( 1 – 3 ) supported by (benzimidazolyl)pyridine alcohol ligands {tridentate [N,N,O]} has been synthesized and well characterized by FT-IR, 1 H and 13 C NMR, elemental analysis and single-crystal X-ray diffraction analysis. In combination with methyllithium, these zinc complexes were proved to be highly efficient initiators for the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL). The ROP of ε-CL in the absence or presence of benzyl alcohol, as well as the influences of monomer concentration, reaction temperature and the substituent on the ligand, were investigated in detail. [ABSTRACT FROM AUTHOR]

Layer-by-layer assembly of nanostructured Bi 0.5Sb 1.5Te 3 thin films were prepared by a simple magnetron sputtering method. X-ray diffraction investigations revealed that all the thin films were well crystallized with preferred orientation along (00 l) direction. Scanning electron microscopy images indicated that nanostructure of the condensed films was stacked by tens of parallel repeating layers. Meanwhile, the particular thicknesses of layers could be controlled in the range of 20–140 nm by adjusting the deposition time. The electrical conductivity and power factor were significantly increased compared with those of ordinary thin films, while the maximum power factor reached 53 μW cm −1 K −2 when the layer thickness was 40 nm. The multi-layered materials are promising candidates for miniaturized modules with their unique properties. [ABSTRACT FROM AUTHOR]

The p-type antimony telluride (SbTe) pillar arrays with unique hierarchical architecture have been self-assembled in large scale by a simple vacuum thermal evaporation technique. The composition and the microstructure of the films are studied by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy. The results show that the hierarchical film with multi-scale and multi-dimensional structure is well-oriented pillar arrays perpendicular to the substrate. A large number of nanowires (NWs) are assembled into a submicro/micro-scaled pillar, while antisite defects and dislocations as well as other defects are found in the one-dimensional NWs. The growth mechanism of such nanostructure is proposed and investigated. The thermoelectric (TE) properties, i.e., electrical conductivity (σ), Seebeck coefficient ( S), and thermal conductivity ( κ) of the films are measured. The properties of the hierarchical SbTe film have been greatly enhanced in comparison with those of the ordinary SbTe films. A TE dimensionless figure-of-merit ZT = 0.88 in the novel hierarchical SbTe film is obtained at room temperature. [ABSTRACT FROM AUTHOR]

Abstract: Core–shell heterogeneous CdTe/TiO2 nanorod arrays have been prepared by a two-step synthesis route through combined hydrothermal growth and magnetron sputtering. The composition and microstructure of the arrays were investigated by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), which show that CdTe nanograins coated on the surface of the single-crystalline TiO2 nanorod arrays to form a type-II heterostructure. Compared with TiO2 nanorod arrays, the spectrum absorption region of CdTe/TiO2 core–shell nanostructure is broadened from ultraviolet light to visible light. The photoelectrodes of CdTe/TiO2 nanorod arrays show better photoelectric properties than those of bare TiO2 nanorod arrays. The output power of CdTe/TiO2 nanorod arrays is 25 times higher than that of a bare TiO2 nanorod array. These results indicate that the photoelectrode of CdTe/TiO2 nanorod array has a promising application in solar cell. [Copyright &y& Elsevier]

Abstract: Oriented n-type bismuth telluride thin films with various layered nanostructures have been fabricated by radio-frequency (RF) magnetron sputtering. The crystal structures and microstructures of the films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The transport properties including carrier concentration, mobility, Seebeck coefficient and in-plane electrical conductivity were measured, which showed strong microstructure-dependent behaviors. The relationship between morphologies and transport properties of the films was explored. The optimal morphology and transport properties of films were obtained at the substrate temperature of 350°C under the pressure of 1.0Pa with oriented layered structure. Based on these results, a formation mechanism of these nanostructures is proposed and discussed. The interfaces and grain boundaries formed in these layered structures are beneficial to the reduction in thermal conductivity, which could result in potential TE films with high ZT value. [Copyright &y& Elsevier]

Abstract: Bi2Te3–Te arrays with sheet–rod multiple heterostructure were obtained in large scale, using Te nanorod arrays as the in-situ templates under solvothermal process. The array is formed by the ordered Bi2Te3–Te rods where Bi2Te3 sheets distribute from the top face to the bottom face along the Te rod vertically. The microstructure of the heterostructure was studied through X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The electrical conductivity and Seebeck coefficient of the arrays were also studied. The course of reaction was monitored so as to propose a possible growth mechanism of such novel heterostructure. The key for the preparation of such heterostructure is to balance the velocity between the dissolution of Te rods and the formation of Bi2Te3 sheets. This synthetic approach could be promising to prepare self-assembled low-dimensional nanoarrays of metals and semiconductors with high yield. [ABSTRACT FROM AUTHOR]

Abstract: The solid electrolyte Li0.5La0.5TiO3 (LLTO) with high lithium ion conductivity was prepared by the conventional solid-state reaction method, and those LLTO powders were mixed with inactive second phase (Al2O3, MgO, SiO2) to give composites. The microstructure and conductivity properties of the composite are investigated by using X-ray diffraction, scanning electron microscope and AC impedance method. Those prepared LLTO is cubic crystal with superstructure. All conductivities of LLTO-based composites decrease with the addition of Al2O3 or MgO, but the grain boundary conductivity increases with the addition of SiO2. [Copyright &y& Elsevier]

Abstract: Local-oriented single-crystalline ZnO nanowires have been synthesized in large scale by a simple microemulsion method in the presence of sulfonate-polystyrene (S-PS) and dodecyl benzene sulfonic acid sodium salt (DBS). The as-prepared product is characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), infrared (IR) spectra and photoluminescence (PL) spectrum. The nanowires exhibit a local congregation and preferentially grow along the [002] facet. FT-IR spectrum indicates that S-PS is adsorbed on the surface of ZnO nanowires. The PL spectrum shows evidently red-shifted ultraviolet (UV) emission. [Copyright &y& Elsevier]

La(OH)3/Ni(OH)2 nanocables and La(OH)3 nanorods were synthesized by the reaction of KOH with La(NO3)3 and Ni(NO3)2 at 180 °C under a hydrothermal conditions. X-ray diffraction, transmission electron microscopy and thermal analyses indicated that the nanocable consists of La(OH)3 core and Ni(OH)2 outer shell. The diameters of the La(OH)3 nanorods range from 20 to 30 nm and the lengths range from 150 to 1000 nm. The thickness of the Ni(OH)2 coating ranges from 10 to 20 nm. The formation mechanism of the nanocables is discussed. [Copyright &y& Elsevier]

Novel chainlike nanocrystals of Bi2Te3 and Ag were synthesized via a solvothermal process in the presence of ethylenediaminetetraacetic acid disodium salt or poly (vinyl pyrrolidone) at 180 °C. The products were characterized by X-ray diffraction and transmission electron microscopy. Bi2Te3 nanocrystals were sheet-rods with the ordered array of Bi2Te3 nanosheets, and the Ag chains consist of Ag nanoparticles. Organic ligands play a manifold role in the formation of the chainlike nanostructures as both coordinate ligand and architecture template, and a possible formation mechanism is proposed. [Copyright &y& Elsevier]

A novel silver nanostructure with a chainlike fractal network was self-organized synthesized via a simple solvothermal process by using poly(vinyl pyrrolidone) (PVP) as the coordination reagent. X-ray diffraction indicated that the chainlike fractal networks are of face centered cubic structure. Transmission electron microscopy shows that the diameters of the chain are around 100–150 nm. A Cayley fractal tree model was proposed to explain the formation of fractal geometry. It can be expected that the solvothermal method would be also appropriate for the preparation of such nanostructures for other metals. [Copyright &y& Elsevier]

Surface decoration techniques are emerging as promising strategy to improve the optical properties of the ZnO based materials. The core–shell ZnO/Bi 0.5 Sb 1.5 Te 3 nanorods were grown on a FTO substrate through a facile hydrothermal and magnetron sputtering combined approach. The microstructure of the core–shell nanorod arrays were investigated by the X-ray diffraction (XRD), a field emission Scanning electron microscopy (SEM) and high resolution transmission electron microscope (HTEM). The optical properties of the core–shell nanorod arrays were investigated through the diffuse reflectance absorption spectra and photoluminescence emission. The visible light absorption and especially the photoluminescence emission of the ZnO nanorods are enhanced markedly with the Bi 0.5 Sb 1.5 Te 3 grains coating the ZnO nanorods through the electron charge. [ABSTRACT FROM AUTHOR]

Abstract: Oriented thermoelectric (TE) p-Sb2Te3 and n-Bi2Te3 thin films with special nanostructures have been synthesized by a simple vacuum thermal evaporation technique. The composition and microstructure of the films were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM), presenting a well preferential crystal growth with dense slender columnar grains grown perpendicular to the substrate, and energy dispersive X-ray spectrum (EDX) indicating the compositions distribution in the films. The electric transport properties, i.e., conductivity and Seebeck coefficient, and the thermal transportation of the oriented films show optimized properties. Prototype devices were built up by p and n elements in series and parallel circuits. The largest output power and cooling could be achieved in Sb2Te3 parallel device with P max =6.51μW at ΔT =106K, and cooling of 4.1K at 2V. The 24-pair p–n couples series device could output maximum voltage of 313mV at ΔT =102K. The power generation and the cooling of the devices show times enhanced TE performances than those consisting of common films. The results proved that introducing nanostructures into films is an effective choice to obtain high-efficient micro TE device. [Copyright &y& Elsevier]

• Bi 2 Te 3−x Se x was synthesized in 2 s at room temperature using Bi, Te and Se powders. • The synthesized Bi 2 Te 3−x Se x compound has micro-nano composite structure. • Local Joule heat and ultra-high self-heating rate are inferred for the synthesis. • Mechanism includes Joule heating, melting, reaction, nucleation and grain growth. The synthesis of Bi 2 Te 3−x Se x (x = 0 and 0.3) compounds in a few seconds at room temperature was realized by reactive flash sintering method using Bi, Te and Se raw powders. The phase transition and microstructure evolution during flash sintering were systematically studied relating to the duration time, power density and sample temperature. The synthesized Bi 2 Te 3−x Se x compounds have micro-nano composite structure, which are composed of 5–10 μm lamellar crystal and 10–20 nm nanograin. It is suggested that the instantaneously generated local Joule heat throughout the sample and the resulted ultra-high self-heating rate approaching tens of thousands K/min are responsible for the synthesis of highly crystalline Bi 2 Te 3−x Se x. The synthesis mechanism is proposed, including Joule heating, melting, chemical reaction, nucleation and grain growth. This highly efficient and economic synthesis method of Bi 2 Te 3−x Se x compounds with micro-nano composite structure has great potential for application in the field of thermoelectric industry. [ABSTRACT FROM AUTHOR]

Abstract: Belt-like X-doped VO2(M) (X=W, Mo, Sn or Fe) with rectangular cross sections were successfully synthesized by a facile one-pot hydrothermal approach. The as-obtained samples were characterized by XRD, XPS, SEM, DSC and variable-temperature IR. The results showed that the additives W, Mo, Sn and Fe could promote the formation of VO2(M) under hydrothermal conditions. The additives had little influence on the morphology of doped VO2(M), but they were the key factor for the synthesis of VO2(M). The W and Mo atoms could effectively reduce the T c of VO2(M), while Sn and Fe atoms had little influence on T c. Furthermore, it was found that the as-obtained doped VO2(M) possessed prominent thermochromic properties and optical switching characters. [Copyright &y& Elsevier]

Abstract: A series of cobalt(II) complexes containing 2-imino-1,10-phenanthrolines have been synthesized and characterized by elemental and spectroscopic analysis. The molecular structures of complexes 2, 3, 8 and 14 were confirmed by X-ray diffraction analysis. On treatment with methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), these cobalt(II) complexes show moderate to high catalytic activities for ethylene oligomerization and butene predominates among the oligomers produced. The parameters of the reaction conditions and the effects of the ligands environment were investigated. To cite this article: S. Jie et al. C. R. Chimie 9 (2006) . [Copyright &y& Elsevier]