自恢复保险丝的封装工艺

选择改性环氧树脂作聚乙烯／炭黑自恢复保险丝的封装材料,研究了封装对保险丝热特性的影响,封装层影响芯料的散热能力,当通过电流足够大时,封装对保险丝的动作时间几乎没有影响,当通过电流较小时,封装层在120℃（聚乙烯熔点）下固化的保险丝由于封装层与芯料之间存在一定的空隙,芯料散热能力变差,且芯料的热膨胀可以顺利进行,动作时间变短。因此,保险丝封装应在芯料达到最大热膨胀的温度下进行。     

Significance of temperature increase in processing by high-pressure torsion

Experiments and finite element simulations were conducted to measure the temperature increase in processing disc samples by high-pressure torsion. Aluminum, copper, iron and molybdenum were selected as model materials. The temperature increases at the early stages of straining but saturates to steady-state levels at large strains. The increase of temperature is proportional to the hardness and rotation speed and is higher at higher imposed pressures and is somewhat higher at larger distances from the disc center.     

杭氧高压充瓶压缩机技术的发展

简要介绍杭氧充瓶氧压机更新换代的历史过程和应用技术的发展状况,指出各代充瓶氧压机的优缺点,并介绍杭氧目前已初步形成的充瓶用氧、氮压缩机产品系列化的主要参数,可供用户优化组合选型时参考。     

包装机械设计中的控制技术

在简单介绍包装机械的基础上,分析了包装机械各主要组成部分对控制的要求,提出了解决包装机械控制系统设计的方法及实用参考程序.     

A visualization of shear strain in processing by high-pressure torsion

Optical microscopy was used to examine the shear strain imposed in duplex stainless steel disks during processing by high-pressure torsion (HPT). The results show a double-swirl pattern emerges in the early stages of HPT and the two centres of the swirl move towards the centre of the disk with increasing revolutions. Local shear vortices also develop with increasing numbers of revolutions. At 20 revolutions, there is a uniform shear strain pattern throughout the disk and no local shear vortices.     

Fatigue behaviour of an autofrettaged high-pressure vessel for the food industry

The autofrettage technique is commonly used to produce compressive tangential residual stresses near the bore of high-pressure vessels. These compression stresses improve the fatigue life of the vessel during the loading–unloading high-pressure cycles. The present paper presents the fatigue design of an autofrettaged thick-walled vessel for the food industry, working at an internal pressure of 500 MPa. A finite element analysis has been performed in order to obtain the residual stresses after the autofrettage at an internal pressure of 925 MPa. The material of the vessel was a 15-5PH stainless steel hardened by precipitation, which shows a strong Bauschinger effect. For FE simulations, the material has been modelled considering an elastic–perfectly plastic behaviour for the loading phase and a Ramberg–Osgood behaviour for the unloading phase, with its coefficients depending on the previous equivalent plastic strain reached during the loading process. The simulation procedure is explained in detail. Finally, the fatigue life of the vessel was obtained using the residual stresses obtained in the previous simulations stage.     

Using high-pressure torsion for metal processing: Fundamentals and applications

High-pressure torsion (HPT) refers to the processing of metals whereby samples are subjected to a compressive force and concurrent torsional straining. Although the fundamental principles of this procedure were first proposed more than 60 years ago, processing by HPT became of major importance only within the last 20 years when it was recognized that this metal forming process provides an opportunity for achieving exceptional grain refinement, often to the nanometer level, and exceptionally high strength. This review summarizes the background and basic principles of processing by HPT and then outlines the most significant recent developments reported for materials processed by HPT. It is demonstrated that HPT processing leads to an excellent value for the strength of the material, reasonable microstructural homogeneity if the processing is continued through a sufficient number of torsional revolutions and there is a potential for achieving a capability for various attractive features including superplastic forming and hydrogen storage. The review also describes very recent developments including the application of HPT processing to bulk and ring samples and the use of HPT for the consolidation of powders.     

Structural and morphological transformations of carbon nanospheres during high-temperature,high-pressure processing

This paper presents analysis of structural changes in powders consisting of turbostratic carbon spheres with an average particle diameter of 250 and 25 nm after high-temperature, high-pressure processing at a pressure of 8 GPa. It has been shown that marked ordering of graphene sheets is observed at 1300°C and actively proceeds at higher temperatures. The major morphological species in the samples after processing is slabs of graphene sheets, and three-dimensional structural perfection is higher at the smaller particle size. Using high-resolution electron microscopy, samples of this powder were shown to contain diamond nanocrystallites.     

Effect of temperature on the processing of a magnesium alloy by high-pressure torsion

It is now well known that processing by SPD can significantly increase the strength of metallic materials by refining the grain structure and increasing the density of defects. The rapid increase in strength observed in the early stages of deformation is expected to slow down and saturate at large strains because of an increasing recovery of the material. Therefore, a saturation strength is anticipated that will depend on the processing temperature. This investigation analyses this parameter by determining the evolution of hardness of a magnesium alloy processed by high-pressure torsion at different temperatures.     

Strengthening of Al through addition of Fe and by processing with high-pressure torsion

Iron is a common impurity element in aluminum and is expected to be used in a controlled manner. In this study, high-pressure torsion (HPT) was applied to 10-mm diameter bulk disk-type samples of Al–Fe alloys with different Fe additions: 2 and 4 wt%, and different initial states: as-cast, extruded, and annealed. Intense strain was introduced to the materials by HPT processing at room temperature under a pressure of 6 GPa for up to 75 revolutions. Tensile tests showed that a significant increase in the UTS above 500 MPa occurs with 13 % elongation in the Al–2 % Fe sample processed by HPT from the as-cast state. Microstructural analyses revealed that a close-to nanograined microstructure with a size of 125 nm and dispersion of intermetallic particles below 50 nm was attained, along with a maximum supersaturation of Fe of ~0.67 wt%. The Al–4 % Fe sample reached even higher supersaturation of Fe to ~0.99 % and similar strength but lower elongation due to insufficient fragmentation of coarse intermetallics. It is concluded that the eutectic structures in the cast state are a major contributor to the enhanced strengthening and the retained elongation. The saturated states of the microhardness at equal Fe contents were shown to be similar regardless of the initial state upon sufficient straining by HPT.     

Trends in food processing and packaging technologies

During the past 10 years, quite a number of new technologies, both in processing and packaging, have emerged and made an impact on shelf-life of food products. These technologies have also matched some consumer trends, such as concerns regarding freshness and health. This evolution will continue but with a new element built in, i.e. the environmental issue.     

Effect of strain reversals on the processing of high-purity aluminum by high-pressure torsion

High-purity aluminum was processed by high-pressure torsion (HPT) under conventional monotonic (m-HPT) and cyclic (c-HPT) conditions where strain reversals are introduced in c-HPT during processing. Measurements show higher values of the Vickers microhardness in the center regions of all disks but these values are higher when processing by c-HPT by comparison with m-HPT for the same total number of turns. Slightly smaller grain sizes are observed in the c-HPT samples. It is shown that all of the microhardness values correlate with the estimated values of the equivalent strain and the results are consistent with earlier data reported under c-HPT conditions when it is recognized that the variation of hardness with equivalent strain is dependent upon the level of recovery within the material.     

Radiometric sensor for temperature control of food processing

This paper describes a novel planar antenna sensor created for the purpose of noninvasive temperature measurements using microwave radiometry. In order to improve radiometric measurements in industrial applications, a new generation of sensors is introduced, composed of a metallic sheet. Simulations based upon the method of moments is used both to design and to determine their electromagnetic performances. This paper also describes a radiometric device using these sensors to measure and control the temperature of food products during deep freezing processes. The results and discussions are presented.     

包装用纸正向技术含量高、功能化方向发展

当今,随着科学技术的飞速发展和人们环保意识的日益增强,包装用纸正向技术含量高、功能化方向发展.     

2010年上海市包装技术协会十大活动

一、召开协会第八次代表大会 协会于12月16日在科学会堂召开第八次代表大会。会议通过了以“转变发展方式,转向服务经济——为全面提升上海包装业整体水平而努力”的工作报告。大会还通过了协会章程修改报告、第七届理事会财务工作报告及关于收取会费标准的意见,选举了协会第八届理事会。大会上还举行了“星级包装企业”授牌仪式。     

Evaluating the influence of pressure and torsional strain on processing by high-pressure torsion

Tests were conducted on an Al-6061 alloy to evaluate the separate effects of the applied pressure and the torsional straining in processing by high-pressure torsion (HPT). The values of the Vickers microhardness were measured after processing and plotted both linearly across the diameters of the disks and as three-dimensional representations. The measurements show that the applied pressure increases the hardness in the absence of torsional straining. In the presence of a pressure and torsional straining, the hardness values are high at the edges of the disk but lower in the central region. There is a gradual evolution toward a hardness homogeneity with increasing numbers of HPT revolutions. The hardness values at the edges of the disks are reasonably independent of the applied pressure but the extent of this region of high hardness depends upon both the applied pressure and the numbers of turns in the HPT processing.     

食品无菌包装技术的发展概况

近年来,各种无菌包装的商品在世界各国的超级市场上十分流行。采用无菌包装的食品营养损失小,风味色泽基本不变,无需冷藏便可长期贮存,这些优点越来越受到广大厂家和消费者的喜爱,是未来食品包装发展的必然趋势。