CO2置换天然气水合物中CH4的研究进展

在全面综述国内外天然气水合物开采技术研究现状的基础上,重点介绍了国内外CO2置换开采天然气水合物的研究进展,分别从热力学和动力学角度分析了置换反应过程的可行性. 现有的研究主要集中在自由饱和水体系,而自然界中天然气水合物主要赋存于海底沉积层和永久冻土层中,需结合天然气水合物赋存的自然环境条件,研究其动力学过程,揭示置换反应过程的内在机理. 最后指出了CO2置换开采天然气水合物尚存在的问题和今后的研究方向.     

克劳斯催化过程的实际情况

结合现场操作情况,考查了在克劳斯催化剂上H2S／SO2转化反应的基本化学原理。结果表明,在缺氧条件下硫酸盐在催化剂表面的形成是克劳斯催化过程中的一种基本情况,也是降低CS2转化率和导致催化剂因BTX降解而结垢的原因。结合催化剂表面天然硫酸盐的生成,对更换催化剂和高比值浸润问题进行论述。最后考查了亚露点操作的催化剂设计问题。     

铁粉在酸解钛液还原反应中的应用

介绍了铁粉代替铁屑在酸解钛液还原反应中的应用。试验结果表明，铁粉还原剂具有还原反应快、计量准确、用量少、对酸解钛液的稳定性和产品质量无影响等特点，且经济效益好。     

扩散和化学反应的多物质格子气自动机模型

运用细胞自动机模型方法,建立了多物质格子气自动机模型,并对混合体系中的扩散传质和简单气固相化学反应现象进行了模拟.结果表明,作为一种从微观离散运动论角度模拟宏观现象的方法,多物质格子气自动机模型可以定性模拟一些典型的扩散和化学反应现象.     

Software-guided Microfluidic Reaction Calorimeter Based on Thermoelectric Modules

A software-guided, continuous reaction calorimeter based on thermoelectric modules for direct heat flux measurements is presented. Sensors and actuators of the calorimeter's setup are implemented within a lab automation system, which enables the automated calibration of the heat flux sensors and investigations of chemical reactions through sequential function charts. Functionality of the calibration is shown by heat transfer experiments. Additionally, the calorimeter's performance is demonstrated by good agreement of conducted neutralization experiments with literature data.     

High solids content emulsions. IV. Improved strategies for producing concentrated latices

A new means of producing high solids content latices with low viscosity is presented. The replacement of water‐soluble initiators that decompose to give charged free radicals is shown to perturb the stability of highly concentrated latices. Their replacement by an oil‐soluble initiator during particle growth, then by an activated, water‐soluble system to remove residual monomer has been shown to help significantly reduce the number of stable particles generated by homogeneous nucleation. Latices with 73% (v/v) solids have been produced with a bimodal particle size distribution (PSD) consisting of 900 and 110 nm particles. The viscosity of these latices can be as low as 300 mPa s^?1 at 20 s^?1. Despite the presence of water‐soluble monomers, excellent control over the evolution of the PSD allows one to obtain highly reproducible results. In addition, latices produced with the new initiator system have a much lower water uptake and their viscosity is much less sensitive to changes in pH than is the case for latices produced using standard emulsion polymerization techniques. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1935–1948, 2002; DOI 10.1002/app.10514     

Conjugate mathematical model of ignition of magnesium samples

A distributed mathematical model of ignition of a magnesium particle with allowance for the heterogeneous chemical reaction and the region of the thermal influence of the particle on the gas is developed. A solution of the problem in a steady formulation is found, which allows expanding the classification of the thermal history of the particle-gas system. A numerical model for solving the considered class of boundary-value problems of magnesium-particle ignition is proposed, and the mathematical model is verified in terms of the ignition delay as a function of the Nusselt number. A limiting size of the gas layer near the particle, which determines the ignition mode, is identified. Stability of some heating regimes to finite and infinitesimal disturbances is demonstrated. It is shown that the ignition process can be controlled by a high-frequency thermal action on unstable states of the particle-gas system. __________ Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 3, pp. 57–63, May–June, 2006.     

基于复合神经网络的离散非线性系统建模与控制

An adaptive inverse controller for nonliear discrete-time system is proposed in this paper. A compound neural network is constructed to identify the nonlinear system, which includes a linear part to approximate the nonlinear system and a recurrent neural network to minimize the difference between the linear model and the real nonlinear system. Because the current control input is not included in the input vector of recurrent neural network (RNN), the inverse control law can be calculated directly. This scheme can be used in real-time nonlinear single-input single-output (SISO) and multi-input multi-output (MIMO) system control with less computation work. Simulation studies have shown that this scheme is simple and affects good control accuracy and robustness.     

THE STRING OF CATALYST SPHERES AS A TOOL FOR HEAT AND MASS TRANSFER STUDY IN A THREE-PHASE SYSTEM

A single vertical string of catalyst spheres with liquid film flowing over their surfaces was employed to model a three phase system. Simultaneous heat and mass transfer characteristics within a porous catalyst pellet and across the laminar liquid film was analyzed in terms of different values of reaction and transport parameters. It is shown that the liquid film thickness after the first three pellets reduces less than 10% even though a highly exothermic reaction is taking place within the pellets. It was also found that the mixing in pendular rings plays an important role in heat transfer from the pellets surface.     

Application of atactic polypropylene in technology of chemical foaming of PVC pastes

A preliminary study of the use of by-product atactic polypropylene as a replacement for plasticizer in chemically blown plastisol is presented. The effect of varying amounts of PP and plasticizer on the elastic property was studied. Atactic PP has been shown to be useful as a plasticizer substitute in plastisols in amounts apt. 10%.     

Fabrication of palladium coated nanoporous gold film electrode via underpotential deposition and spontaneous metal replacement: A low palladium loading electrode with electrocatalytic activity

An electrochemical approach to nanoporous film-based gold catalyst design using the underpotential deposition and redox replacement technique is presented. The procedure consisted of the underpotential deposition (UPD) of copper on the gold nanoporous film, with subsequent replacement of the copper by palladium at open circuit in a palladium containing solution. The resulting electrode was studied using cyclic voltammetry and scanning electron microscopy. The electrocatalytic activity of as-prepared palladium nanoporous gold film electrodes toward the oxygen reduction reaction is presented.     

2-芳基苯并呋喃化合物的新法合成与表征

创造了两步合成2-芳基苯并呋喃化合物的新方法。即利用水杨醛或取代水杨醛在低价钛作用下进行交叉McMurry偶联反应,并对交叉偶联产物-邻乙烯基苯酚进行氧化环化获得对应苯并呋喃化合物。此法为脱甲氧基野茉莉醇、野茉莉醇等天然产物的全合成提供了简便有效的方法。     

一种新型单体填料的气液接触性能

本文试验研究了新近研制的组合环 (UR)单体填料的流体力学和传质性能 ,并对其泛点和压降进行了关联。结果表明 ,这种填料具有通量大、阻力小和传质效率高的优点 ,可望代替鲍尔环、环矩鞍等常用填料。     

水性防腐蚀转化涂料的研制

水性防腐蚀转化涂料以具有优良稳定性的氯醚乳液作为基料，通过与复合锈转化剂及多种颜填料组合而成。结果表明其具有优异的锈转化及防腐蚀作用，在一般外防腐蚀涂装中可替代除锈前处理工作，且具有与多种涂料配套使用的能力。     

High-alumina ramming mixture with an additive of disthene-sillimanite concentrate

A laboratory study aimed at replacing expensive chamotte from Chinese bauxites used in a ramming mixture by disthene-sillimanite concentrate is described. It is shown that partial replacement of the chamotte by disthene-sillimanite concentrate can give the required high-alumina ramming mixture. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 7, pp. 33–34, July, 1997.     

二(2-乙基己基)磷酸萃取L-色氨酸

以二 (2 -乙基己基 )磷酸 (D2EHPA) -正辛烷 (体系A)及D2EHPA -正辛醇 +正辛烷 (体系B)萃取L -色氨酸为对象 ,研究了D2EHPA浓度、L -色氨酸初始浓度、稀释剂组成以及pH值对萃取平衡分配系数的影响 .结果表明 ,在实验研究涉及的pH值 (1.0     

Enhancement of phenolic polymer properties by use of ethylene glycol as diluent

One application of phenolic resins is for the inner lining of multilayered composites in fire critical applications. Typically such resins contain water as a diluent to facilitate injection and mold filling. Although water is effective in controlling the viscosity, its evaporation from the resin during cure has been found to cause microvoids in the cured resin that are 8–10 μm in size. These voids are believed to affect the properties of the final product. In addition to the initial water content, evolution of water also takes place as a result of cure. In this study, we investigated the effects of processing parameters such as cure temperature, postcure temperature, catalyst concentration, and the use of ethylene glycol as a replacement diluent on water loss, microvoid distribution, and consequently, the mechanical properties. Weight loss during cure was followed by using a thermogravimetric analyzer (TGA). Scanning electron microscopy (SEM) was used to obtain images of cured resin showing the microvoids. The properties that have been obtained for comparison are density, flexural modulus and strength, and fracture toughness. It has been shown that modification of the resin by removing the initial water of a commercial resin system and adding ethylene glycol as a replacement has the most significant effect on the microvoids as well as the properties of the polymer. A decrease in void content and increase in density along with a significant improvement in flexural modulus and fracture toughness have been observed upon replacement of water with ethylene glycol. This is significant because of the importance of the phenolic layer to the overall mechanical performance of a hybrid composite. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3096–3106, 2004     

Alkali-silica reactivity of large silica fume-derived particles

Pozzolanic materials, including silica fume, are commonly added to concrete to reduce expansion due to alkali-silica reaction (ASR). It has been noted, however, that commercial silica fume is not always adequately dispersed, and large agglomerates may be present. These large particles have been hypothesized to act as amorphous silica aggregates, thereby participating in an expansive reaction with the alkalis present in cement paste pore solution. If such were the case, some silica fume particles would actually aggravate expansion due to ASR rather than suppress it. The present investigation characterizes the microstructure and morphology of agglomerated and sintered silica fume particles and compares their effects on alkali-silica-related expansion. While a 5% replacement of moderately reactive sand with sintered silica fume aggregates caused significant expansion under accelerated testing conditions (modified ASTM C1260), the replacement with large agglomerates of densified silica fume decreased expansion compared with control mortar bars containing only sand. Both the sintered aggregates and the agglomerates reacted with the pore solution; one reaction was expansive, while the other was not.     

Transport properties study of supplementary cementitious materials: case of tuff,limestone filler and granodiorite

The aim of this research is to determine the effects of replacing cement with tuffs on the transport properties and service life of cement-based materials. Specimens were prepared replacing 5% and 15% by weight of cement with both white and brown tuffs. Additional specimens were prepared replacing cement with 5% and 15% limestone filler and granodiorite to compare the effects of these types of materials. For these four types of specimen as well as a control mortar with no cement replacement transport properties (gas permeability and chloride ingress) were measured as well as porosity and pore diameter. The transport properties were compared the changes in these porosity and pore diameter. Based on the results, white tuff significantly improves the transport properties of the mortars due to its pozzolanic reaction and that white tuff may be an economically and functionally viable replacement for cement where concrete durability is important. Pore diameter and porosity did not correlate well with transport properties.     

Slag resistance of chamotte refractories with particolored clay

A laboratory study of slag resistance of fireclay specimens on substitution for clay DN2 in the binding part of the mixture by a refractory clay is presented. The slag resistance is determined by the crucible method. It is shown that the replacement by the refractory clay for DN2 does not cause a decrease in the slag resistance of refractories of equivalent density. The results of the laboratory study have been confirmed by full-scale tests.