煤层气地质选区评价方法研究

在以往研究的基础上,对煤层气地质选区评价方法进行了研究。结果表明,煤层气地质选区评价的实质是要寻找富集、高渗、高压的含煤区。在煤层气地质选区方法方面除了要考虑煤层的基本性质（如煤层厚度、埋深、变质程度、含气量）外,更重要的是要研究煤层气高产富集的主控地质因素,如构造运动、沉积史、生烃史及三者间的关系,煤层上覆地层连续沉积厚度、瓦斯风化带、水文条件等方面对煤层气保存条件的影响;还要考虑古、今应力场对煤层渗透率的影响。这样才能搞清煤层气高产富集条件,指导煤层气地质选区评价研究。以大城地区、开平向斜及沁水盆地为例分析了煤层气保存条件并预测了煤储层高渗区,预测结果与实际试验吻合程度较高。     

Structure and photoconductive properties of dip-deposited SnS and SnS2 thin films and their conversion to tin dioxide by annealing in air

SnS and SnS₂ thin films have been prepared by the dip technique. In this technique, a substrate was dipped into an alcoholic solution of the corresponding chloride and thiourea and then withdrawn vertically at a controlled speed, and finally baked in a high temperature furnace at atmospheric condition. XRD and SEM data suggest that good quality SnS and SnS₂ films are obtained at a baking temperature of 300 and 360°C, respectively. Values of band gap for SnS and SnS₂ obtained from spectral response of photoconductivity are 1.4 and 2.4 eV, respectively. The indirect allowed band gap values for SnS₂ film obtained from optical absorption measurements are 1.95 and 2.05 eV. Open-air annealing of both SnS and SnS₂ films at 400°C converts them to transparent conducting SnO₂.     

高效率平面磁控溅射器的研制

介绍一种新型磁控溅射装置。它采用两块极性相对的环状磁铁的设计方法，通过扩大靶表面的等离子放电区域面积，使传统磁控溅射枪使用中经常受到的两个限制──溅射速率与靶的利用率得到了较大的改善。实验中铜靶在溅射功率密度为11W／cm~2时溅射速率约为800nm／min，如果继续提高功率则可获得更高的速率。而靶的利用率可达64％左右。另外，在认为出射粒子符合cos~nθ分布的前提下，发现当n＝3．3时，实验数据和理论数据符合得较好。     

Growth structure investigation of MgF2 and NdF3 films grown by molecular beam deposition on CaF2(111) substrates

The growth structure of MgF₂ and NdF₃ films grown on polished CaF₂(111) substrates deposited by molecular beam deposition has been investigated using transmission electron microscopy (TEM) of microfractographical and surface replications as well as cross-sectional TEM, atomic force microscopy, packing density, and absorption measurements. It has been shown that by taking advantage of ultrahigh vacuum environments and a special stratification property of MgF₂ and NdF₃ films, the preparation of nanocrystalline films of high packing density and low optical absorption is possible at a substrate temperature of 425 K.     

A theory for the formation of tetrahedral amorphous carbon including deposition rate effects

A theoretical model is presented to describe the effect of ion beam bombardment rate on the formation of tetrahedral amorphous carbon (ta-C) films. The critical ion energy, E_c, corresponding to a 50% sp³ content in the films, is found to be dependent on both the effective thermal resistance and the ion beam bombardment rate. In the model, the ‘window’ width in the ion energy scale for the formation of ta-C material increases with decreasing deposition rate and with a reduction in the effective thermal resistance, until limited by lower and upper boundary thresholds. Experimental data are reproduced by the model. The plasmon energy, which correlates with sp³ fraction, is found experimentally of be higher for lower deposition rate and smaller effective thermal resistance. Data points for high sp³ content ta-C films deposited on silicon substrates at room temperature occupy a region in the ion energy-deposition rate (E-r) diagram similar to that predicated from the theory.     

Electrophoretic deposition of chitosan

The electrophoretic deposition (EPD) of chitosan on metallic substrates was investigated. The electrophoretic mobility of the natural biopolymer in aqueous solution as a function of pH was studied. Because the protonation/deporotonation of chitosan is pH-dependent, the electrophoretic mobility and deposition rate is shown to increase with increasing pH from 2.9 to 4.1. The film growth rate is estimated to vary in the range 0.02–0.08 µm/s depending on the pH value. At high growth rates (> 0.05 µm/s), a porous film is obtained due to hydrogen entrapment. The EPD method developed here is applicable for the surface modification of metal implants by chitosan to develop novel bioactive coatings.     

Large sized cubic BN reinforced nanocomposite with improved abrasive wear resistance deposited by cold spray

In this work, large sized cubic BN (cBN) reinforced nanocomposites are prepared by cold spray deposition of blended powder mixtures of mechanically alloyed 40 vol.% cBN–NiCrAl nanocomposite particles and large sized cBN particles. Deposition behavior of the blended powders, microstructure and mechanical properties including hardness, fracture toughness and two-body dry abrasive wear behavior of the sprayed composites, are investigated. Results show that dense composites with large cBN particle content of 13–20 vol.%, depending on composition of the spray powders, can be obtained. Declining deposition efficiency is detected as increasing large cBN content due to the gradually enhanced sand blasting effect. Increasing content of large cBN in spray powder results in an increment in hardness and a decrement in fracture toughness. Abrasive wear resistance of the 40 vol.% cBN–NiCrAl nanocomposite is doubled by incorporating 20 vol.% of the large cBN particles. Worn surface morphology observation indicates that the improvement is due to the shielding effect of the large protruding cBN particles against SiC abrasive. Material removal mechanism of the sprayed composites during abrasive wear test is also studied.     

Fabrication of polymer thin films with in-depth dye-dispersed structures by the vacuum spray method

We report the fabrication of polymer thin films with “in-depth” dye-dispersed structures using a vacuum spray method. Copper (II) 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine [(t-Bu)₄CuPc] and polycarbonate in chloroform solution were sprayed onto the substrate. The (t-Bu)₄CuPc distribution was controlled precisely during thin film growth by varying its concentration in the solution. Uniform, bilayer, and gradient structures of (t-Bu)₄CuPc dispersed in thin films were confirmed by high-angle annular dark field imaging on scanning transmission electron microscopy. The vacuum spray method has several advantages compared to the casting method, such as smaller dispersed dye-aggregates and lack of cavities due to air bubbles.     

Structural evolution of PZTN thin films produced by pulsed laser ablation deposition

The study of highly oriented Nb-doped PZT thin films deposited by laser ablation on n-type (111) Si substrates is reported. Sintered ceramics based on the nominal composition Pb_0.995(Zr_0.65Ti_0.35)_0.99Nb_0.01O₃ (PZTN) with an excess of PbO were used as targets. The films were deposited using the 3rd harmonic (355 nm) of a pulsed Nd:YAG laser (7 ns pulse duration) with 7 J/cm² fluence, at different oxygen pressures (from 10⁻¹ to 10⁻⁴ mbar) and at a vacuum of 10⁻⁶ mbar. The substrate temperature was varied in the range of 500-600 °C. In optimized conditions, the as-deposited PZT-based films show perovskite structure oriented along the (110) direction with minor impurities (PbO), as revealed from X-ray diffraction spectra. Further, microstructural analysis of the as-grown including chemical composition is also presented. The relationship between composition of the target, deposition conditions and film properties are then discussed.     

Preparation of floral-patterned ZnO/MWCNT heterogeneity structure using microwave irradiation heating method

HNO₃-treated multi-walled carbon nanotubes enclosed by flower-like zinc oxide particles were prepared by a microwave irradiation heating method. The product was characterized by X-ray diffraction and scanning electron microscopy. It was found that the flower-like zinc oxide grows around the multi-walled carbon nanotubes to form a floral-patterned structure. Multi-walled carbon nanotubes play a role as a template for the growth of ZnO and they can link ZnO particles together as a complex fabrication. This discovery is useful for nano-electronic applications.