Forced convection subcooled boiling of binary mixtures

A mode based on an additive mechanism of heat transfer is proposed for forced convection subcooled boiling of binary mixtures. The contributing modes of heat transfer are: (i) the heat transferred as latent heat by the rising bubbles, (ii) the heat transferred as the heat contained in the superheated thermal layer that is removed from the surface in the wake of the rising bubbles and (iii) the single phase forced convection heat transfer from the heating surface not influenced by the bubbles. Experimental data from the literature on binary systems show good agreement with the model, validating the postulated mechanism.     

Mechanoluminescent pulse pressure sensors. Processing of output optical signal

The process of mechanoluminescence transformation of a pulse pressure sensor is considered. The process consists in excitation of emission under the action of mechanical loading. An algorithm for use in processing the output optical signal of the sensor that makes it possible to determine an input shock pulse is presented. __________ Translated from Izmeritel’naya Tekhnika, No. 10, pp. 28–31, October, 2007.     

微电机与微加工

简述了和微电机相关的微加工生产中的方法，介绍了微型机电部件成型的实现途径。     

Development of ultra light magnesium-lithium alloys

Magnesium-lithium alloys are among the lowest density metallic materials. Addition of lithium, with a relative density of 0·53, in magnesium reduces the density of the alloy significantly. Furthermore, addition of nearly 11 wt.% lithium converts hexagonal close packed structure of pure magnesium to a body centered cubic lattice, markedly improving formability of the alloy. The development of these alloys, however, had been hampered due to the high reactivity of lithium and magnesium in the molten state and also, due to poor creep resistance and instability of mechanical properties at room temperature. In an attempt to indigenize these ultra light alloys for possible applications in Indian satellite programme, detailed research work was initiated in DMRL. The difficulties associated with producing sound cast ingots have been overcome by controlling melting and casting parameters of these alloys. Extensive work has been done on structure-property correlation of alloys with varying lithium content and minor alloying additions. Based on these work, advanced magnesium-lithium alloys have been developed with improved tensile properties, room temperature stability and creep resistance. Wrought products (plates/sheets) of magnesium-lithium alloy have been supplied to ISAC, Bangalore and are being used in their INSAT-2 programme. This paper describes the systematic studies carried out in the laboratory to indigenize these ultra light alloys.     

金线断口的分析

运用扫描电子显微镜技术，对金线断口观察分析，讨论金线在拉伸过程中断裂时断口形貌及断裂的原因，发现，断裂是由于金锭中的气体和杂质引起的，并提出改进生产工艺的意见。     

含微量元素铜焊锡丝的研制

在６０／４０的锡铅焊料中加入０．２％左右的铜，凝固后具有均匀细小的共晶组织，其熔点为１８３℃，焊点强度和扩展率均高于未加铜的６０／４０锡铅焊料，并且含铜的锡铅焊料在焊接时，对铜烙铁头和微细铜线了小的熔蚀性。     

提高气门弹簧钢丝质量的途径

指出了影响气门弹簧钢丝疲劳性能的主要因素是冶金因素，介绍了国外先进的气门弹簧钢丝生产的冶炼、轧制和拉拔新工艺，提出了提高国产气门弹簧钢丝质量应采取的措施。     

回火处理对高碳冷拔钢丝强度和塑性的影响

研究了６５钢冷拔钢丝在５００℃不同时间回火时的抗拉强度和延伸率的变化。试验结果发现，在回火初期，抗拉强度首先增长，然后随口火时间的延长连续降低，而延伸率始终在增长，增长速度是先快后慢。这种行为可归因于第一内应力的消除和ε－碳化物在形变铁素体中的析出以及后来再结晶的发生。     

Dislocations and flux pinning in YBa2Cu3O7

The dislocation structures of bulk textured and epitaxial thin film YBa₂Cu₃O₇ superconductors are examined. Correlations between increases in flux pinning and dislocation densities are noted. A model for flux pinning by individual dislocations is presented. This gives a treatment of strain induced effects and effects of normal state region interactions. It is shown that the values of pinning predicted are in line with experimental observations.