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。     

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.     

Particle processing technology

In recent years, there has been strong demand for the development of novel devices and equipment that support advanced industries including IT/semiconductors, the environment, energy and aerospace along with the achievement of higher efficiency and reduced environmental impact. Many studies have been conducted on the fabrication of innovative inorganic materials with novel individual properties and/or multifunctional properties including electrical, dielectric, thermal, optical, chemical and mechanical properties through the development of particle processing. The fundamental technologies that are key to realizing such materials are (i) the synthesis of nanoparticles with uniform composition and controlled crystallite size, (ii) the arrangement/assembly and controlled dispersion of nanoparticles with controlled particle size, (iii) the precise structural control at all levels from micrometer to nanometer order and (iv) the nanostructural design based on theoretical/experimental studies of the correlation between the local structure and the functions of interest. In particular, it is now understood that the application of an external stimulus, such as magnetic energy, electrical energy and/or stress, to a reaction field is effective in realizing advanced particle processing[1 Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar]3 Sakka Y and Uchikoshi T 2010 KONA Powder Particle J. 28 74 (kona.or.jp/search/28_074.pdf) [Google Scholar]].

This special issue comprises 12 papers including three review papers. Among them, seven papers are concerned with phosphor particles, such as silicon, metals, Si₃N₄-related nitrides, rare-earth oxides, garnet oxides, rare-earth sulfur oxides and rare-earth hydroxides. In these papers, the effects of particle size, morphology, dispersion, surface states, dopant concentration and other factors on the optical properties of phosphor particles and their applications are discussed. These nanoparticles are classified as zero-dimensional materials. Carbon nanotubes (CNT) and graphene are well-known one-dimensional (1D) and two-dimensional (2D) materials, respectively. This special issue also includes two papers on the fabrication of mechanically reliable nanocomposites by dispersing graphene into a ceramic matrix, and on supercapacitors with high energy densities in a Co(OH)₂ system decorated with graphene and carbon nanotubes. As a novel preparation method of oxide films, the fabrication of alumina films with laminated structures by ac anodization is reviewed. Moreover a new type of nanosheet has been fabricated by the exfoliation of layered, ternary transition-metal carbide and nitride compounds, known as Mn 1 Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar]1 Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar]AXn phases (or MAX phases) where M is an early transition metal, such as Ti or Nb, A is an A group element, such as Si or Al, X is carbon and or nitrogen and n 1 Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar]1 Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar]3 Sakka Y and Uchikoshi T 2010 KONA Powder Particle J. 28 74 (kona.or.jp/search/28_074.pdf) [Google Scholar][4] Naguib M, Mashtalir O, Carle J, Presser V, Lu J, Hultman L, Gogotsi Y and Barsoum M W 2012 ACS Nano 6 1322 [Google Scholar]. Among the MAX phases, those containing Mo have been theoretically calculated by first-principles calculations to be a source for obtaining Mo₂C nanosheets with potentially unique properties. As an example of improving bulk ceramic properties, texturing by using a high magnetic field[5] Sakka Y and Suzuki T S 2005 J. Ceram. Soc. Japan 113 26 [Google Scholar] and sintering by the electric current activated/assisted sintering (ECAS) technology[6] Grasso S, Sakka Y and Maizza G 2009 Sci. Technol. Adv. Mater. 10 053001 [Google Scholar] have been demonstrated for ultra-high temperature ceramics with high-temperature strength.

A project on the development of materials and particle processing for the field of environment and energy has been ongoing at the National Institute for Materials Science since April 2011. This project employs various core competence technologies for particle processing such as ion beam irradiation for nanoparticle fabrication[7] Nakao H, Tokonami S, Hamada T, Shiigi H, Nagaoka T, Iwate F and Takeda Y 2012 Nanoscale 4 6814 [Google Scholar], fullerene nanomaterial processing using liquidliquid interface precipitation[8] Miyazawa K and Hotta K 2010 J. Cryst. Growth 312 2764 [Google Scholar], a gas reduction nitridation process to obtain Si₃N₄-based phosphor materials[9] Suehiro T, Xie R and Hirosaki N 2013 Indust. Eng. Chem. Res. 52 7453 [Google Scholar], advanced phosphors via novel processing[10, 11] Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar], ultra-high pressure technology for processing and in situ analysis[12 Kawamura F, Yusa H and Taniguchi T 2012 Appl. Phys. Lett. 100 251910 [Google Scholar], 13] Watanabe K and Taniguchi T 2011 Int. J. Appl. Ceram. Technol. 8 977 [Google Scholar], colloidal processing in a high magnetic field to obtain laminated, textured ceramics[1, Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar] 3, Sakka Y and Uchikoshi T 2010 KONA Powder Particle J. 28 74 (kona.or.jp/search/28_074.pdf) [Google Scholar] 5] Sakka Y and Suzuki T S 2005 J. Ceram. Soc. Japan 113 26 [Google Scholar], the ECAS process for nanostructuring ceramics[6] Grasso S, Sakka Y and Maizza G 2009 Sci. Technol. Adv. Mater. 10 053001 [Google Scholar] and so forth. Here, I would like to introduce some research achievements that are not covered in this special issue.

(1) The evolution of hydrogen by the reaction of fine metal particles such as Al[14] Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar] and Mg[15] Uda M, Okuyama H, Suzuki T S and Sakka Y 2012 Sci. Technol. Adv. Mater. 13 025009 [Google Scholar] with water; the specific surface area and surface modification are important factors.

(2) The realization of new carbon related materials with 1D and 2D structures consisting of fullerenes prepared by liquid liquid interface precipitation: alkaline-doped superconductive nanotubes consisting of fullerenes[16] Takeya H, Kato R, Wakahara T, Miyazawa K, Yamaguchi T, Ozaki T, Okazaki H and Takano Y 2013 Mater. Res. Bull. 48 343 [Google Scholar], application to solar cells of fullerene/cobalt porphyrin hybrid nanosheets[17] Wakahara T, D Angelo P, Miyazawa K, Nemoto Y, Ito O, Tanigaki N, Bradley D D C and Anthopoulos T D 2012 J. Am. Chem. Soc. 134 7204 [Google Scholar], etc.

(3) The fabrication of textured films and bulk materials with excellent functional properties by colloidal processing methods such as slip casting[5] Sakka Y and Suzuki T S 2005 J. Ceram. Soc. Japan 113 26 [Google Scholar], gel casting[18] Wiecinska P, Sakka Y, Suzuki T S, Uchikoshi T, Mizerski T and Szafran M 2013 J. Ceram. Soc. Japan 121 89 [Google Scholar] and electrophoretic deposition[3, Sakka Y and Uchikoshi T 2010 KONA Powder Particle J. 28 74 (kona.or.jp/search/28_074.pdf) [Google Scholar] 19] Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar], in a high magnetic field, and with subsequent heating; examples of such materials include dye-sensitized TiO₂ solar cells, thermoelectric materials and cathode materials for solid state Li-ion batteries and dielectric ceramics.

(4) The fabrication of high-strength and high-toughness MAX phase ceramics[20 Hu C, Sakka Y, Grasso S, Nishimura T, Guo S and Tanaka H 2011 Scr. Mater. 64 765 [Google Scholar], 21] Hu C, Sakka Y, Nishimura T, Guo S, Grasso S and Tanaka H 2011 Sci. Technol. Adv. Mater. 12 044603 [Google Scholar] inspired by the nacreous structure[22] Kakisawa H and Sumitomo T 2011 Sci. Technol. Adv. Mater. 12 064710 [Google Scholar].

(5) The modeling and development of the ECAS process[6] Grasso S, Sakka Y and Maizza G 2009 Sci. Technol. Adv. Mater. 10 053001 [Google Scholar]. This involves two-step pressure application[23] Grasso S, Hu C F, Maizza G, Kim B N and Sakka Y 2011 J. Am. Ceram. Soc. 94 1405 [Google Scholar] and high-pressure application above 400 MPa to fabricate transparent oxides[24 Grasso S, Kim B N, Hu C F, Maizza G and Sakka Y 2010 J. Am. Ceram. Soc. 93 2460 [Google Scholar]26] Kim B-N, Hiraga K, Grasso S, Morita K, Yoshida H, Zhang H and Sakka Y 2012 J. Ceram. Soc. Japan 120 116 [Google Scholar], and rapid heating to obtain dense nanocomposites of ceramic–CNT[27] Estili M, Kawasaki A and Sakka Y 2012 Adv. Mater. 24 4322 [Google Scholar] and diamonds[28] Grasso S, Hu C F, Maizza G and Sakka Y 2012 J. Am. Ceram. Soc. 95 2423 [Google Scholar].

(6) The contraction of ternary phase diagrams for oxide ion conductor systems such as zirconia[29] Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar] and apatite systems[30] Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar], leading to an increased understanding of the stability of such systems and assisting the search for high oxygen ion conductors.     

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.     

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.     

超声技术在食品加工中的应用

简要评述了超声技术的基本原理和优点,阐述了超声技术在面包等食品加工中应用的现状及面临的机遇,分析了该领域的研究空间和发展潜力,初步进行了超声技术应用在面包上的具体典型实验实例,根据实验目的,从被加工表面的表面粗糙度、切片变形形状以及加工表面的温度变化等情况,详细地对比分析了增加超声和未增加超声的不同效果。根据实验结果结合当前面包等食品加工行业现状,构思基于超声技术的面包等食品加工的专用设备的工作原理方案。该设备有助于提高面包等食品加工的产品质量,为发展超声技术在食品加工中的应用提供一定的参考。     

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 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.     

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.     

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.     

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.     

Packaging for high‐pressure treatments in the food industry

This study highlights some important aspects of the package, such as packaging materials suitable for high‐pressure treatments, package properties (barriers and flexibility) and package integrity. Six different types of package were tested. They consist of multilayer plastic packages (PA/PE), where thickness, permeability and stress varied at yield point and at breakage. They achieve a good heat seal and good protection from the pressure medium (water) surrounding them. Experiments were carried out at 200, 350 and 500 MPa for 30 min at ambient temperature, comparing the performance of pressurized multilayer plastic packages with untreated packages. Different simulants (water, 3% acetic acid, 15% ethyl alcohol and olive oil), in contact with the packages, were used to demonstrate the good integrity between package and foodstuff during treatment and shelf‐life. Copyright © 2000 John Wiley & Sons, Ltd.