Effects of surfactant/silica and silica/cerium ratios on the characteristics of mesoporous Ce-MCM-41

Using the surfactant CTMABr (cetyltrimethyl ammonium bromide) and cerium(IV) sulfate, mesoporous Ce-MCM-41 molecular sieves were produced under a hydrothermal condition with various surfactant/silica (surfactant/Si) and silica/cerium (Si/Ce) ratios. Changes to the structural traits caused by changing the molar ratios of both surfactant/Si and Si/Ce were investigated. XRD (X-ray diffraction), FT-IR (fourier transform infrared spectroscopy), and SEM (scanning electro microscopy) were used for the characterization of prepared mesoporous samples. Among the tested molar ratios, surfactant/Si ratio of 0.5 and 0.2 showed highest values of d_1 0 0 and intensity, respectively, for the Si-MCM-41. XRD analysis also identified a quintessential hexagonal structure of Ce-MCM-41 for the Si/Ce molar ratio higher than 40 (maintaining the surfactant/Si ratio at 0.2). When cerium content was increased to have the Si/Ce molar ratio of 20, the hexagonal structure of Ce-MCM-41 was collapsed due to the structural stress of substituted cerium. FT-IR results confirmed calcination of Ce-MCM-41 and the incorporation of Ce⁴⁺ ions of cerium sulfate into the silica surface with proper removal of the surfactant. Rod-like shape with rounded edges of the prepared Ce-MCM-41 samples was identified by SEM. These results suggest surfactant/Si ratio of 0.2 and Si/Ce ratio of 40 for the production of Ce-MCM-41 with the highest level of crystallinity.     

提高开卷线纵剪机精度的研究

通过对纵剪机右立柱轴承间隙测量方法和左立柱导向结构的改进，保证了加工精度，易于操作，提高了生产效率。     

下T6-361井多井防碰绕障技术

下T6—361井是一口双靶定向井，由于受地面和地质条件的限制，必须穿越9口井，其中最近的4口井防碰距仅为13—32m，钻井施工难度大，是一口较典型的多井防碰绕障定向井。在优化井身剖面设计、优选钻具组合、采用导向钻井技术的基础上，采取了一系列安全钻进措施，顺利钻至设计井深。对该井的地质工程设计、井眼轨迹控制及防碰绕障技术等进行了介绍，对同类型井的施工有一定的借鉴。     

汽车漆漆膜质量的改进与提高

通过对车身漆膜质量问题的分析,采取专业清洁公司整体承包车间保洁、工艺方面改进、更换生产外材料、供应商加强对汽车漆使用的监控等一系列措施,漆膜质量水平得以提高.     

Optimization of the magnetic circuit in the MFL inspection system for storage-tank floors

Magnetization is the key to inspection of a tank floor via the magnetic-flux-leakage (MFL) technique. In order to optimize the magnetic circuit of the MFL detector and obtain the best detection effects, the influences of the magnet size on the floor magnetization condition, the gap magnetic flux density, and the magnetic force were studied with the help of the finite element method (FEM) and the effects of some other parameters, such as the magnet pole spacing and pole-piece thickness, on the signal-to-noise ratio were analyzed. The simulation results indicate that variation of the magnet width affects the magnetization much more than variation of the magnet thickness and that the detector can reach a trade-off between the magnetization effects and the driving force when the magnet is about 30 mm thick and 40 mm wide. On condition that the floor has reached its magnetizing saturation, an increase in the magnet-pole spacing and the pole-piece thickness can improve the testing sensitivity and the signal-to-noise ratio. The text was submitted by the authors in English.     

快速色谱分析技术在油气勘探中的应用

文章通过对五口井的现场应用介绍，阐述了快速色谱分析技术在油气层识别和解释方面的准确性，探讨了该技术在薄油气层的发现和评价、快速钻进条件下油气层的发现、对油气层全烃组份变化的统一、水平井的地质导向以及排除钻井液添加荆对油气显示的影响五个方面的优势，从而论证了快速色谱分析技术在油气勘探中的应用价值。     

Hydrothermal Reaction Mechanism and Pathway for the Formation of K2Ti6O13 Nanowires

Calculations and detailed first principle and thermodynamic analyses have been performed to understand the formation mechanism of K₂Ti₆O₁₃ nanowires (NWs) by a hydrothermal reaction between bulk Na₂Ti₃O₇ crystals and a KOH solution. It is found that direct ion exchange between K⁺ and Na⁺ plus H⁺ interactions with [TiO₆] octahedra in Na₂Ti₃O₇ promote the formation of an intermediate H₂K₂Ti₆O₁₄ phase. The large lattice mismatch between this intermediate phase and the bulk Na₂Ti₃O₇ structure, and the large energy reduction associated with the formation of this intermediate phase, drive the splitting of the bulk crystal into H₂K₂Ti₆O₁₄ NWs. However, these NWs are not stable because of large [TiO₆] octahedra distortion and are subject to a dehydration process, which results in uniform K₂Ti₆O₁₃ NWs with narrowly distributed diameters of around 10 nm.     

Collision-Free Interleaver Composed of a Latin Square for Parallel-Architecture Turbo Codes

In parallel-architecture turbo codes, the constituent interleavers must avoid memory collision. This paper proposes a collision-free interleaver structure composed of a Latin square (LS) and pre-designed interleavers. Our proposed interleavers can be easily optimized for various information block sizes and for various degrees of parallelism. Their performances were evaluated by computer simulation.     

烧结成品运输自动控制系统的改进

对烧结成品运输自控系统不稳定性因素进行了分析，提出了采取优化硬件外围工作环境，完善软件保护程序等改进措施。改进后的自控系统稳定性明显提高。     

Effects of Y and Ce on Microstructures and Properties of Nb-Si System Composites

The effects of yttrium and cerium on microstructures and properties of Nb-Si system composites were investigated by scanning electron microscopy( SEM), energy dispersive spectrum(EDS), X-ray diffraction(XRD) and high temperature oxidation experiments.It is found that the coarse primary silicide phase became finer and more homogeneous with Y and Ce addition.The results of high temperature oxidation experiments show that the oxidation rates of NbSi system composites with an appropriate amount of Y and Ce decrease compared with those of alloys without Y or Ce addition, and oxidation products mainly distribute along the phase boundaries between the Nb solid solution and silicide.