基于工业以太网传输的胶带运输集中控制系统

该文介绍了华丰煤矿井下胶带输送机集中控制系统的组成、功能和特点。系统采用现场总线+工业以太网网络结构,实现了控制数据、语音传输、图像传输三网合一。     

构造因素对断陷湖盆陆相层序影响机理的计算机模拟

综合考虑陆源碎屑物供给、内源碳酸盐沉积、沉积物侵蚀与再沉积、重力沉沉积以及构造升降和水平位移等诸多地质因素,建立了一个能够模拟各型盆地层序地层的综合数学物理方程式.采用自行研制的定量层序地层模拟系统,以断陷湖盆陡坡带(泌阳断陷双河一赵凹地区)为例,在假定出平面变化呈一正弦函数曲线,物源供给速率中等、匀速的条件下,分别模拟了盆地加速沉降和减速沉降两种过程的陆相层序响应特征.研究结果表明,一个构造沉降旋回过程控制着一个陆相层序及其体系域的发育和形成.     

Ni–SiO2 and Ni–Fe–SiO2 catalysts for methane decomposition to prepare hydrogen and carbon filaments

Active and stable Ni–Fe–SiO₂ catalysts prepared by sol–gel method were employed for direct decomposition of undiluted methane to produce hydrogen and carbon filaments at 823 K and 923 K. The results indicated that the lifetime of Ni–Fe–SiO₂ catalysts was much longer than Ni–SiO₂ catalyst at a higher reaction temperature such as 923 K, however, a reverse trend was shown when methane decomposition took place at a lower reaction temperature such as 823 K. XRD studies suggested that iron atoms had entered into the Ni lattice and Ni–Fe alloy was formed in Ni–Fe–SiO₂ catalysts. The structure of the carbon filaments generated over Ni–SiO₂ and Ni–Fe–SiO₂ was quite different. TEM studies showed that “multi-walled” carbon filaments were formed over 75%Ni–25%SiO₂ catalyst, while “bamboo-shaped” carbon filaments generated over 35%Ni–40%Fe–25%SiO₂ catalysts at 923 K. Raman spectra of the generated carbons demonstrated that the graphitic order of the “multi-walled” carbon filaments was lower than that of the “bamboo-shaped” carbon filaments.     

Silicon nanowires coated with copper layer as anode materials for lithium-ion batteries

Silicon nanowires (Si NWs) with copper-coating as high capacity and improved cycle-life anode for lithium-ion batteries have been successfully prepared by chemical vapor deposition and magnetron sputtering methods. The morphology, structure, composition as well as the electrochemical performance of copper-coated Si NWs is characterized in detail. The results indicate that the copper-coated Si NWs electrodes show an initial coulombic efficiency of 90.3% when cycling between 0.02 V and 2.0 V (versus Li/Li⁺) at a current density of 210 mA g⁻¹. The copper-coated Si NWs electrodes exhibit a capacity as high as 2700 mAh g⁻¹ at the first cycle. They also show a good capacity retention and excellent rate capability compared with pristine and carbon-coated Si NWs.     

Fast reconstruction of computerized tomography images based on the cross-entropy method

Computerized tomography (CT) has been applied to multi-phase flow measurement in recent years. Image reconstruction of CT often involves repeatedly solving large-dimensional matrix equations, which are computationally expensive, especially for the case of on-line flow regime identification. In this paper, a minimum cross-entropy (MCE) reconstruction based on wavelet multi-resolution processing, i.e., an MRMCE method, is proposed for fast reconstruction of CT images. Each row of the system’s matrix is transformed by 1-D wavelet decomposition. A regularized MCE solution is obtained using the simultaneous multiplicative algebraic reconstruction technique (SMART) at a coarse resolution level, where important information of the reconstructed image is contained. Then the solution in the finest resolution is obtained by inverse fast wavelet transformation (IFWT). Both computer simulation and experimental work were carried out for oil-gas two-phase flow regimes. Results obtained indicate that the MRMCE method improves the resolution of the reconstructed images and dramatically reduces the computation time compared with the traditional linear back-projection (LBP), MCE and algebraic reconstruction technique (ART) methods. Furthermore, the new method can also be used to accurately estimate the local time-averaged void fraction of dynamic two-phase flow. It is suitable for on-line multi-phase flow measurement.     

CORBA和AGENT技术在网络应用模拟系统中的应用

CORBA技术和Agent技术是两种热门技术,它们具有各自的优势,而且可以相互补充。这两种技术在网络系统开发中具有广泛的应用,分析它们的长处可以提出一套可行的系统开发模型。本文就是在分析CORBA技术和Agent技术的基础上提出了一种网络系统开发模型,并运用这种模型成功地开发出网络应用模拟系统。     

ROBUST STABILITY ANALYSIS FOR RAILWAY VEHICLE SYSTEMS

The lateral stability for railway vehicle dynamic system with uncertain parameters and nonlinear uncertain force vector is studied by using the Lyapunov stability theory. A robust stability condition for the considered system is derived, and the obtained stability bounds are not necessarily symmetric with respect to the origin in the parameter space. The lateral stability analysis for a railway bogie model is analyzed by using the proposed approach. The symmetric and asymmetric results are both given and the influence of the adjustable parameter β on the stability bounds is also discussed. With the help of the proposed method, the robust stability analysis can provide a reference for the design of the railway vehicle systems.     

茶皂素的提取及其应用研究进展

茶皂素是一种纯天然非离子型表面活性剂，在工农业生产中有广泛的应用。本文综述了茶皂素的提取方法以及在工农业、医药等领域中的应用概况，并提出了今后的开发前景。     

Quality evaluation of Panax notoginseng extract dried by different drying methods

Quality control still remains a big issue, affecting herbs, formulations, and even the practice of Traditional Chinese Medicine. A promising solution to the problem is to take advantage of innovative process techniques including alternative drying methods within the pharmaceutical processing. Nowadays, vacuum belt drying (VBD) has gained more and more importance in food and pharmaceutical processing. In this work, Panax notoginseng extract was made into powder by the gentle VBD as well as by classical spray drying (SD), freeze drying (FD), and vacuum drying (VD). Certain chemical and physical properties of the dried powders such as moisture content, drying time, porosity, density, saponins content, pH value and hydroxyl radicals scavenging activity were evaluated. The results showed the qualities of dried products were influenced to different extent by drying methods certainly. Vacuum belt drying was suggested to dry P. notoginseng extract for its high quality assurance of hygroscopic products and suitable for sticky or high viscous products.     

Dark current and photovoltage models on the formation of depletion region in C60/NPB organic heterojunctions

We establish quantitative models on the formation of depletion regions in organic photodiodes (OPD) based on fullerene/N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4′-diamine (C₆₀/NPB) heterojunctions. The models describe the relation of dark current and open-circuit voltage to the deposited thickness of C₆₀ or NPB. Interfacial electronic structures, such as built-in potential, the charge density, the minimized thicknesses of completely developed depletion regions and the energy level bending on each side of the heterojunction were derived from the fitting model. Also, we observed a shift of depletion region from NPB to C₆₀ due to the relative change of charge density under illumination. The device performance proved the reasonability of the models. This paper provides a universally applicable method to probe the interfacial information of organic semiconductors.