激光熔覆等离子喷涂Al2O3陶瓷涂层组织结构研究

研究了45钢表面激光熔覆等离子喷涂Al2O3陶瓷涂层的组织结构、显微硬度及滑动磨损特性.结果表明,等离子喷涂Al2O3涂层的组织呈层片状,层间为机械结合,涂层由α-Al2O3, ZrO2和少量γ-Al2O3组成;激光熔覆Al2O3陶瓷涂层组织为细小枝状晶,由α-Al2O3及少量ZrO2组成.激光熔覆Al2O3涂层的显微硬度较高,滑动磨损时耐磨性明显优于等离子Al2O3喷涂层.     

AZ91D-RE-xCa镁合金挤压管件组织及性能

研究了镁合金AZ91D加入混合RE及Ca进行合金化后的AZ91D-RE-xCa（x=0．5、1．0、1．5）镁合金挤压管件的显微组织、室温及高温（150℃和200℃）力学性能。结果表明，合金化之后的镁合金挤压管件高温性能得到了显著的提高。在200℃时，钙含量（质量分数）为0．5％时，δb为225．2MPa，δ0.2为179．3MPa，δ为5．3％，好于同等试验条件下的镁合金AZ91D管件。     

Ba和Sm双原子填充Skutterudite化合物的制备及热电性能

以Ba和Sm作为填充原子，用熔融法结合放电等离子快速烧结（SPS）制备出了单相的Ba和Sm复合填充的Skutterudite化合物BamSmnFexCO4-xSb12,研究了两种原子复合填充总量及填充比例对其热电性能的影响规律。结果表明：随着Ba和Sm双原子复合填充总量的增加，P型BamSmnFexCo4-xSb12化合物的Seebeck系数增加、电导率和热导率降低。当复合填充总量相近时，Ba原子填充比例较大的Skutterudite化合物，其电性能稍好：而Sm原子填充比例较大的Skutterudite化合物，其热导率稍低。本研究中Ba0.218Sm0.204Fe1.51Co2.50Sb12化合物的最大热电性能指数ZTmax。值在800K时为0．75。     

中国压铸市场的机遇与挑战

评述了中国压铸市场的现状和发展前景。2002年，全国压铸件总产量为62．4万t，其中：铝合金压铸件产量为41．56万t，锌合金压铸件产量为19．82万t，镁合金压铸件产量为0．50万t，铜合金压铸件产量为0．53万t，分别占66．6％，31．87％，0．8％，0．8％；压铸机年销售量近1800台；2lD02年，全国模具总产值达到360亿元，其中压铸模约占10％；全国压铸行业中，外资企业、民营企业、乡镇企业以及私营企业合计已达到压铸企业总数的80％以上，特大型压铸企业集团开始涌现。     

Analysis of corrosion resistance behavior of inhibitors in concrete using electrochemical techniques

Reinforced concrete is one of the most durable and cost effective construction materials. However, in high chloride environments, it can suffer from corrosion due to chloride induced breakdown of the normal passive layer protecting the reinforcing steel bars inside concrete. One means of protecting embedded steel reinforcement from chloride induced corrosion is the addition of corrosion inhibiting admixtures. In the present investigation, various inhibitors such as sodium nitrite, zinc oxide, mono ethanol amine, diethanolamine, and triethanol amine have been used in concrete in different percentages. Their effectiveness was then studied using various electrochemical techniques such as rapid chloride ion penetration test, open circuit potential measurement, electrochemical impedance measurement, potentiodynamic polarization measurement, and gravimetric weight loss measurement. The results thus obtained indicate that the addition of inhibitors enhances the corrosion resistance properties.     

红外成像技术在GIS设备检漏中的应用

应用红外成像泄漏检测仪器,采用两种方法对三峡电厂、葛洲坝电厂、溪洛渡电厂、向家坝电厂的GIS设备分别进行了检测。结果表明:大面积无目的普查难以发现泄漏点,而对疑有泄漏的地方进行定位检测,当泄漏量达到一定程度时,可以直观地发现泄漏点。     

Incorporating Intra‐Query Term Dependencies in an Aspect Query Language Model

Query language modeling based on relevance feedback has been widely applied to improve the effectiveness of information retrieval. However, intra‐query term dependencies (i.e., the dependencies between different query terms and term combinations) have not yet been sufficiently addressed in the existing approaches. This article aims to investigate this issue within a comprehensive framework, namely the Aspect Query Language Model (AM). We propose to extend the AM with a hidden Markov model (HMM) structure to incorporate the intra‐query term dependencies and learn the structure of a novel aspect HMM (AHMM) for query language modeling. In the proposed AHMM, the combinations of query terms are viewed as latent variables representing query aspects. They further form an ergodic HMM, where the dependencies between latent variables (nodes) are modeled as the transitional probabilities. The segmented chunks from the feedback documents are considered as observables of the HMM. Then the AHMM structure is optimized by the HMM, which can estimate the prior of the latent variables and the probability distribution of the observed chunks. Our extensive experiments on three large‐scale text retrieval conference (TREC) collections have shown that our method not only significantly outperforms a number of strong baselines in terms of both effectiveness and robustness but also achieves better results than the AM and another state‐of‐the‐art approach, namely the latent concept expansion model. © 2014 Wiley Periodicals, Inc.     

How do Individual‐Level Factors Affect the Creative Solution Formation Process of Teams?

The generation of creative solutions involves nonlinear dynamic procedures that can only be achieved through the creativity of individual team members. Thus, it is important to understand how the formation of individual‐level creativity factors influence the creative solution formation process. The creative solution formation process can be divided into four phases: idea generation, idea screening, idea development and solution verification. Prior research suggests that the creative process may be affected by motivation (intrinsic and extrinsic), knowledge stock (explicit and tacit), individual creativity (intelligence and divergent thinking), and pressure (challenge and time). We tested the effects of these eight factors on performance in the idea generation and idea development phases by conducting an experiment. Our results indicate that intrinsic motivation, intelligence and divergent thinking have a significant positive effect on both idea generation and idea development. Tacit knowledge and challenge pressure have a significant positive effect on idea generation. Time pressure has a significant negative effect on idea development. We also show that both idea generation and idea development have a significant impact on the quality of the final creative solution.     

Comparison of spherical and non-spherical particles in microchannels under dielectrophoretic force

This paper focuses on the computational and experimental study of dielectrophoretic (DEP) force based manipulation of spherical and non-spherical particles by taking into consideration of both electrokinetic effects and particle hydrodynamics. The model is first validated with conventional dipole moment theory. The movements of a spherical polystyrene particle and a rod-shape particle under a non-uniform electric field created by a pair of non-symmetrical electrodes in a microfluidic channel are studied, and a good agreement between the simulation and experimental results is obtained. Both experimental and simulation results reveal that the rod-shape particle experiences larger DEP force and moves faster than spherical particle with a similar mass. It was also interestingly found that the shape-dependent DEP force distribution on the microscale rod particle results in its unique behavior, which cannot be captured by traditional DEP theory.