含硫化氢气井钻井过程中的腐蚀因素与防护研究

在含硫气井的钻井过程中对于HRC大于22的钻具钢材除了腐蚀疲劳之外，在pH值小于9的环境中会发生硫化物应力腐蚀破裂，这种破坏比腐蚀疲劳更突然、更快，使钻杆大量损坏。含硫气井在钻井过程中，由于湿硫化氢的出现，常常会出现油管、套管、钻井设备、钻井仪器以及对支持保护管柱的水泥环柱等腐蚀和损坏问题，为此，阐述了湿硫化氢的腐蚀特点、机理，归纳总结了影响腐蚀的因素，综述了如何在这些方面防止其腐蚀，使损失减小，为指导油管、套管防腐工程实践提供了依据。建议在钻井过程中采用碱性钻井液，其pH值可到9或更高(至pH值12)，以减缓或防止钻井过程中电化学从硫化物应力腐蚀破裂；含硫气井用的钻杆应该间歇使用。钻杆停用堆置时间可使其放氢，使钻杆恢复韧性，防止硫化物应力腐蚀断裂。     

真空高压气淬热处理

影响模具使用寿命的因素固然很多，但采用合理的热处理工艺相当重要。我厂采用真空高压气淬热处理工艺取得了很好的效果，尤其是成型模具。经过处理后的模具无氧化脱碳，变形小，表面非常洁净光亮。模具比一般热处理具有更高的强度、耐磨性、韧性和疲劳强度，使用寿命提高２～３倍以上。真空高压气淬原理：工件在抽成一定真空度的炉内，在负压气氛条件下加热和保温后，充入高压惰性气体，通过大功率风机进行冷却淬火。具有如下特点：（１）无氧化脱碳。由于被抽成真空，炉内氧化性和脱碳性气体极少，可防止氧化、脱碳，起到保护作用。炉内氧…     

Electrophoretic deposition of electrolyte materials for solid oxide fuel cells

Electrophoretic deposition of electrolyte materials for solid oxide fuel cells, including La_0.8Sr_0.2Ga_0.875Mg_0.125O_3–x , yttria stabilized zirconia and (Ce_0.8Gd_0.2)O_1.9, was studied under various experimental conditions. The use of phosphate ester as a dispersant and poly (vinyl butyral) as a binder enabled high deposition rate and formation of crack-free, adherent deposits. Electrodeposition rates were quantified in experiments performed at constant current and constant voltage modes from suspensions in ethanol, isopropanol and mixed ethanol—isopropanol solvents. The microstructure of as prepared and sintered deposits was studied by electron microscopy. The bath composition was optimized to enable formation of dense deposits.     

The Bi-Rb (bismuth-rubidium) system

This work was supported by ASM International. Literature searched through 1988. Dr. Pelton is the Alloy Phase Diagram Program Co-Category Editor for binary alkali alloys.     

A brief review of the ionic conductivity enhancement for selected oxide electrolytes

The advantages of lowering the operation temperature of SOFCs have attracted great interest worldwide. One of the major barriers to decreasing the operation temperature is the ohmic loss of the electrolyte. Maximizing the electrolyte ionic conductivity is of significant importance, especially in the absence of new electrolyte materials. The ionic conductivity of electrolytes can be influenced by many parameters. There has been an enormous effort in the literature for the improvement of the electrolyte ionic conductivity. From a practical point of view, this paper reviews various approaches to enhancing the ionic conductivity of polycrystalline zirconia- and ceria-based oxide electrolytes in the light of composition, microstructure, and processing. Suggestions are given for future work.     

Comparison of Representative Heuristic Algorithms for Multi-Objective Reservoir Optimal Operation

Heuristic algorithms (HAs) are widely used in multi-objective reservoir optimal operation (MOROO) due to the rapidity of the calculation and simplicity of their design. The literature usually focuses on one or two categories of HAs and simply reviews the state of the art. To provide an overall understanding and a specific comparison of HAs in MOROO, differential evolution (DE), particle swarm optimisation (PSO), and artificial physics optimisation (APO), which serve as typical examples of the three categories of HAs, are compared in terms of the development and applications using a designed experiment. Besides, the general model with constraints and fitness function, and the solution process using a hybrid feasible domain restoration method and penalty function method are also presented. Taking a designed experiment with multiple scenarios, the mean average of the optimal objective function values, the standard deviation of optimal objective function values, the mean average of the computational time, and population diversity are used for comparisons. Results of the comparisons show that (a) the problem of optimal multipurpose reservoir long-term operation is a mathematic programming problem with narrow feasible region and monotonic objective function; (b) it is easy to obtain the same optimal objective function value, but different optimal solutions using HAs; and (c) comparisons do not result in a clear winner, but DE can be more appropriate for MOROO.

     

Mining diversity on social media networks

The fast development of multimedia technology and increasing availability of network bandwidth has given rise to an abundance of network data as a result of all the ever-booming social media and social websites in recent years, e.g., Flickr, Youtube, MySpace, Facebook, etc. Social network analysis has therefore become a critical problem attracting enthusiasm from both academia and industry. However, an important measure that captures a participant’s diversity in the network has been largely neglected in previous studies. Namely, diversity characterizes how diverse a given node connects with its peers. In this paper, we give a comprehensive study of this concept. We first lay out two criteria that capture the semantic meaning of diversity, and then propose a compliant definition which is simple enough to embed the idea. Based on the approach, we can measure not only a user’s sociality and interest diversity but also a social media’s user diversity. An efficient top-k diversity ranking algorithm is developed for computation on dynamic networks. Experiments on both synthetic and real social media datasets give interesting results, where individual nodes identified with high diversities are intuitive.     

Thermal cross-linking and anti-meltdrop properties of copolyester containing phosphorus/magnesium salt composites by in situ polymerization

Polyester is widely used in household products because of its good mechanical properties and wears resistance, but polyester is easy to ignite and inclined to produce droplet, so its application range is limited. The cross-linkable magnesium hydroxide nanoparticles were incorporated into flame-retardant polyester, which enables the phosphorus-containing copolyester with thermal cross-linking and anti-meltdrop properties. The nanoparticles were achieved by in situ polymerization and acted as a nucleating agent for improving the crystalline properties of the copolyester. Furthermore, the nanoparticles also enhanced anti-meltdrop properties and reduced the heat and gas release during the combustion process of the copolyester. The maximum heat release rate and total smoke release reduced by 39.8% and 74.4% compared with pure polyester. Specifically, the combustion products of the nanoparticles and phosphorus flame retardant could act a barrier role by covering the carbon layer to isolate air and heat, thereby resulting in excellent anti-meltdrop properties. The simple modification method reported here realizes the collaborative modification of flame retardant and anti-meltdrop properties of phosphorous flame-retardant copolyesters by thermal cross-linking.     

TiNi形状记忆合金的线性回复行为及其稀土渗入改性

提出了TiNi形状记忆合金线性回复行为的新概念，采用稀土表面渗入化学热处理的方法，研究了对其线性回复性能的影响。实验结果表明：对TiNi形状记忆合金弹簧渗铈(Ce)或渗钐(Sm)，可以显著改善其线性回复性能。线性回复温度范围Tw从4℃拓宽到11℃，线性回复率η从54％提高到78％，线性回复程度PL从56％提高到70％，非线性回复程度Ps从44％减小至8％，但总回复程度PT有所下降。这些结果是由于TiNi合金弹簧渗层中金属问化合物的强化效果所致。