Modeling and optimizing of steel and mushy Al-28Pb alloy bonding

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基于ENC28J60的中央空调节能控制器以太网接口设计

针对中央空调系统的特点,开发了基于ARM的中央空调节能控制器。重点阐述了节能控制器的以太网接口设计,包括物理层的以太网独立控制器ENC28 J60的外围硬件电路设计,驱动程序设计及上层通信协议的设计。网络层、传输层采用嵌入式TCP/IP协议栈,应用层采用Modbus协议。     

二元复合驱采出液破乳剂SH88的小型矿场试验

破乳剂ＳＨ８８是专为辽河油田兴２８块碱／聚合物二元复合驱采出液研制的，由ＡＲ型和ＳＰ型破乳剂复配而成。在处理量２０ｍ３／ｄ的小型矿场脱水试验装置上连续进行了为期半年的兴１９１井采出液破乳脱水试验，ＳＨ８８的脱水效果明显优于常规破乳剂。确定了使用ＳＨ８８时的脱水工艺参数。     

Influence of Silicon Morphology and Mechanical Properties of Piston Alloys

In this paper, the influence of silicon particle morphology on mechanical properties of two piston alloys has been reported. Alloys having nominal composition Al-12%Si-1%Ni-0.8%Cu-0.6%Mg (LM13) and Al-17%Si-1%Ni-0.8%Cu-0.6%Mg (LM28) were prepared by melting and casting. The morphology of silicon crystals was changed using additives during the melt treatment and subsequently by heat treatment. Mechanical properties such as hardness, ductility, and tensile strength of experimental alloys were tested. Test results showed that the melt treatment and heat treatment of both the alloys increased the tensile strength, hardness, and ductility. However, the influence of melt treatment on mechanical properties was not as significant as that of heat treatment. Tensile strength and ductility of LM13 was found to be higher than the LM28 alloy under similar conditions. Hardness of LM28 was higher than the LM13 alloy. Optical and SEM studies showed a change in eutectic silicon morphology on melt treatment of LM13. However, change in morphology of primary silicon particles was not significant as for LM28. Heat treatment of both alloys caused spheroidization and better distribution of eutectic silicon crystals. Sharp-edged primary silicon particles were rounded off after the heat treatment of LM28. Scanning electron microscopy (SEM) of tensile fractured surfaces was carried out to study the influence of microstructure on fracture mode. Heat treatment of both alloys promotes dimple fracture. However, as-cast and melt-treated alloys show predominantly cleavage fracture.     

28CrMo钢表面磁控溅射TiN涂层的组织结构及耐腐蚀性能

为了提高28CrMo钢表面的致密性和耐腐蚀性能,采用磁控溅射技术在28CrMo钢表面制备TiN涂层,通过光学显微镜、X射线衍射仪(XRD)、电化学测试等手段分析了TiN涂层的显微结构及其在3.5%NaCl溶液中的耐腐蚀性能。结果表明:采用磁控溅射技术在28CrMo钢表面制备了厚约0.5μm的TiN涂层,涂层与基体结合良好,没有出现明显的裂纹,涂层表面N的原子分数明显高于Ti;电化学Nyquist谱得到高频区的容抗弧可能是由电荷转移电阻引起和膜层引起,中频区的容抗弧由基体金属溶解时的传质弛豫引起,低频区的感抗弧由基体表面吸附物的弛豫过程引起;3.5%NaCl溶液中腐蚀96 h后TiN涂层表面有蚀坑,吸附有白色疏松的腐蚀产物,并出现大小不一的腐蚀坑;TiN涂层能够明显改善基体的耐蚀性能,对改进高铬钢表面特性具有重要的作用。     

Thermal Diffusivity Measurement of Isotopically Enriched 28-Si Single Crystal by Dynamic Grating Radiometry

In the past decade it has been suggested that the isotopic enrichment of 28-silicon enhances its thermal properties. Thus, 28-silicon is suitable as a heat sink in large-scale integrated circuits. Although some studies have focused on the measurement of isotopically enriched silicon's thermal properties, accurate experimental data are not sufficient because of this material's high conductivity and large heat capacity which make measurement difficult. However, the dynamic grating radiometry (DGR) method has been successfully developed to measure the thermal diffusivity of 28-silicon. In the DGR method, the sample is heated by interference of two pulsed laser beams, and the temperature decay is monitored by an infrared detector. By analyzing the temperature changes of the peaks and valleys of the thermal grating, the thermal diffusivities parallel and perpendicular to the sample surface are obtained simultaneously. In this paper, the optimum conditions of the experimental setup for measuring isotopically enriched silicon are discussed. The comparison of thermal diffusivities between 28-silicon and natural silicon (with a thickness of about 100m) is presented, and the applicability of DGR to isotope engineering is reported.     

Dark matter searches with H.E.S.S.

WIMP annihilations are required to reproduce the correct dark matter abundance in the Universe. This process can occur in dense regions of our Galaxy such as the Galactic center, dwarf galaxies and other types of sub-haloes. High-energy γ-rays are produced in dark matter particle collisions and can be detected by Cherenkov telescopes such as H.E.S.S. We report here the search for γ-ray signals from the Galactic center and the nearby Sagittarius and Canis Major satellites. In the absence of a convincing signal, modelling the dark matter density within these objects allows to put constraints on the WIMP parameters such as its mass and annihilation cross-section. Beyond these targeted searches, the wide-field survey of the inner Galaxy with H.E.S.S. is used to constrain sub-halo formation models involving intermediate-mass black holes.     

KZ-28震源DGPS数据分析与质量控制

本文具体描述了KZ-28可控震源的GPS作业方式、要求、质量控制难点、作业数据检验和质量控制方法,并通过对道达尔试验项目KZ-28震源DGPS作业中存在的数据不匹配等问题进行了分析和研究,探索出其数据处理和质量控制的方法,成功地解决了影响生产的瓶颈问题,确保了地震勘探合作项目的顺利进行。     

Magnetic properties of nanostructural γ-Ni-28Fe alloy

1Introduction The nickel-iron alloys in the permalloy system,with about10%to65%(mass fraction)iron,are probably important soft magnetic alloys[1],which have been widely used in industry,such as recording heads,transformers or magnetic shielding materials.…     

Energy conservation under incompatibility for fluid-structure interaction problems

Concurrent numerical methods for fluid-structure interaction problems are typically based on partitioned solution procedures. However, such partitioned methods are inherently non-conservative. In the present work, we investigate the conservation properties of monolithic discretisations for fluid-structure interaction problems. We consider a prototypical fluid-structure interaction problem, viz., the piston problem. A variational formulation allows us to establish precisely the conservation properties of the continuum problem and its discretisation by the finite-element method. We show that the conservation of energy by monolithic discretisations is only trivially maintained under restrictive compatibility conditions on the approximation spaces in the fluid and the structure. Moreover, we introduce a new discretisation based on coincidence conditions which ensures energy conservation under incompatibility. Numerical results which illustrate the effectiveness of the new discretisation are presented.