真空冷冻干燥技术在果蔬类食品加工中的应用现状

目的 为未来冻干技术在果蔬类及更多食品种类中更广泛的运用提供参考。方法 对近些年来真空冷冻干燥技术在果蔬类食品中的应用进行综述,探讨冻干过程中可能存在的问题,以及一些工艺优化措施。结论 尽管真空冷冻干燥技术的用价高昂,但近些年来由于消费者对少加工、高质量食品的需求,该项技术在食品行业中得到了愈发广泛的应用。近年来,预处理及一些创新技术的工艺强化能够有效地应对真空冷冻干燥技术面临的挑战,随着在线监控、品质智能监测等技术的引入,真空冷冻干燥得到了进一步的发展。     

Herstellung funktionaler organischer Dünnschichten durch Vakuumverdampfung

Depositing of functional organic thin films by vacuum evaporation Material evaporation under high or ultra‐high vacuum conditions has been a well known method of thin film coating since nearly a hundred years. Since discovery of semiconducting organics in the 1970s and 1980s, this technology has been increasingly applied to deposit organic molecular compounds. At the moment especially materials for organic LEDs (OLEDs) and for thin‐film solar cells are in the focus of interest. While organics evaporation makes use of advantages of high‐vacuum coating (purity, compatible processing, masking etc.) there are also dedicated demands on process control coming up. The article describes basic requirements, capabilities of present temperature‐controlled evaporation sources, material‐related features, as well as typical applications.     

Wireless communication using detectors located inside vacuum chambers

Progress in modern vacuum technology requires an increasing number of measurements to be performed in the vacuum environment itself and in many applications data transfer outside the vacuum vessels is both difficult and expensive. This paper explores the potential of wireless technology to transmit data from and into ultra high vacuum (UHV) compatible vacuum chambers using glass viewport windows attached to normal standard flange fittings. The current tests focus in particular on Bluetooth technology, and its characteristics and limitations investigated. Signal propagation has been verified up to about 9 m and the outgassing of components shown to be insignificant in a clean metal-sealed vacuum system down to a pressure of 10⁻⁷ mbar. Some preliminary tests of noise and electromagnetic field immunity have been carried out, confirming the robustness of Bluetooth spread spectrum modulation technique. Signal data from Integrated Circuit Temperature Sensors and Photodiodes have been successfully transmitted from a vacuum chamber, proving the capability of this technology standard to handle both low and high frequency data. The future prospects and the further developments of the approach are also discussed.     

Die Geschichte der Vakuumtechnik

History of vacuum technology With the article “history of vacuum technology” the author presents insights from the philosophical picture of the world 2500 years ago and the thesis of the existence of vacuum through the for 1900 years believed antithesis by Aristoteles, that nature does not allow the existence of vacuum and finally the experimental proof by von Guericke, the founder of vacuum technology, that vacuum exists. The article also highlights some genius scientist's, engineer's and inventor's achievements and milestones. Their scientific models, equations of kinetic gas theories and dynamics as well as experimental results and inventions led to the well appreciated conveniences of mobility, communication, medicine and research of today.     

Neue maßgeschneiderte Vakuumlösungen

New customized vacuum solutions The importance of working under (high) vacuum conditions increases constantly in various applications and technology areas. The GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt has also been continuously working on new optimized customized solutions in this area for decades. As the largest Hessian research organization the GSI has also developed some important inventions in the field of vacuum technology. These are highly vacuum‐tight encapsulated cases and their production, a new laser welding technique for particle‐free encapsulation and an improved method for applying getter layers, in particular for NEG (non‐evaporating getter) layers.     

CXS chemical dry vacuum pump brings smart vacuum to the process industry

The chemical sector as a whole has been quick to recognise the clear advantages of dry vacuum pumps over traditional wet technologies, and dry vacuum pumps are now well established around the world as an efficient, reliable option. A new trend is now emerging: for vacuum to be seen as a ‘utility’. In response, dry vacuum technology is being developed by manufacturers to be available on demand in a ‘plug and pump’ system that requires minimum set‐up and maintenance. The most advanced chemical dry vacuum pumps, such as the new CXS pump from Edwards, deliver exceptional energy efficiency and performance, are cost‐effective to run, and are environmentally sound.     

Flüssigkeitsring-Vakuumpumpen

Liquid ring vacuum pumps – Oldtimers of vacuum technology and yet highly up-to-date Liquid ring vacuum pumps were developed over a hundred years ago. In the meantime, vacuum technology has evolved considerably and offers optimum economic and technical solutions for a wide variety of applications. However, liquid ring vacuum technology still has its reason for existence and is the most suitable principle for vacuum generation in some applications. Thanks to its functionality it is perfectly suited for the extraction of humid gases or vapours. Due to the use of process-compatible operating fluid and the possibility of different construction materials, it can be perfectly matched to different operating fluids and process conditions. In addition, it is available in many sizes on the market and can therefore extract very small and very high quantities of gas and vapour.     

Neue Wege bei der Vakuumerzeugung in der chemischen Verfahrenstechnik

A new dry-compressing vacuum pump which has been specifically developed for chemistry applications and which operates without inner compression, is presented to the engineer active in the area of chemical process engineering, as well as the users of vacuum technology in chemical plants. The economic and ecological advantages of this new vacuum pump are demonstrated on the basis of a real example. Moreover, the potential advantages offered by dry-compressing vacuum pump in the area of process engineering, are discussed.     

真空脉冲渗氮研究

为提高真空热处理技术的应用，我所进行真空脉冲渗氮设备的研制及真空脉冲工艺的研究，研究表明，利用真空热处理技术，进行脉冲渗氮，使渗氮后工件表面脆性小，渗氮层均匀，而且无公害，同时模具的寿命提高1－2倍，并取得一定的经济效益。     

Die Geschichte der Vakuumkühlung. The History of Vacuum Refrigeration

The use of the high evaporation enthalpy of water is one of the oldest technologies of refrigeration for food preservation used by the mankind. One could nearly celebrate the true 5000^th anniversary of this technology. Nowadays we call the refrigeration by evaporation from wet surfaces “adiabatic refrigeration”, it regulates, for instance, our body heat by evaporating sweat. After the introduction of some vacuum pumps into the experimental scientific works, 250 years ago, namely in Great Britan, the modern form of “artificial” refrigeration began its career, the evaporation of liquids under the absence of permanent gasses in vacuum. The vacuum refrigeration has been nearly abruptly stopped by the development of compression refrigeration processes, about 150 years ago. Only after world war 2, a reintroduction of vacuum refrigeration began again. Now, at the beginning of the 3. milennium, there are good chances for recovering terrain.     

钢包真空脱气处理工艺及设备

随着炼钢技术的飞速发展,真空脱气处理技术成为减少钢中气体和非金属杂质的有效措施,其关键在于如何获得真空.本文以某厂利用蒸汽喷射泵的钢水炉外真空处理为例,介绍了真空系统的设备组成,阐述了真空泵的抽气理论,利用边试验边改进的方法来优化蒸汽喷射泵的抽气性能.最后,给出了钢水的真空脱气处理工艺及其效果.     

Carl Hoffmann (1844 – 1910), der Erfinder der Drehschieberpumpe

Among the numerous constructions and designs of mechanical (vacuum) pumps around the turn of the 19th/20th century Hoffmanns invention of the sliding vane rotary vacuum pump may be considered as the real breakthrough in this field. His pump, manufactured since 1905 excels by the introduction of the – by now standard – back pressure valve which has been retained as an essential component in all later constructions of similar pumps, in particular of Gaede's so called “box” pump. The articel describes Hoffmann's professional life in context with the state of vacuum technology at his time.     

Moderne Vakuumelektronik

Modern Vacuum Electronics — between nostalgia and high technology Vacuum electronics is about 140 years old. The operation of vacuum electronic components and devices is based on the motion of electrons or ions in vacuum and diluted gases under the influence of electric, magnetic and electromagnetic fields. The classical radio tube has a nostalgic application in tube amplifiers for music enthusiasts. But presently, research activities are concentrated on absolutely necessary special tubes, especially travelling wave tubes, gyrotrons, klystrons, X‐ray tubes and vacuum pressure measurement gauges. The use of novel fied‐emitter cathodes also enables miniaturization and new applications in modern vacuum electronics. The ITG‐Fachausschuss 8.6 is a competent contact partner for vacuum‐electronic problems. Every two years this committee organizes a workshop in Bad Honnef, Germany.     

3D-Druck für Hochvakuumanwendungen

To mark our anniversary, we are presenting articles that have been particularly appreciated by readers of our online edition once again in print. Here: 3D-Printing for High Vacuum Applications 3D printing technology has made the leap from a home-based private practice to industrial manufacturing. Due to the increasing reliability of printers and increasing material diversity, especially in the metal sector, double-digit percentage growth rates are possible in the coming years. This thesis deals with the manufacture of parts made by 3D printing for high vacuum application. Different components are printed and examined for their vacuum compatibility. As shown furthermore, conventionally made standard components can be vacuum sealed to printed parts, which enables cost-effective production of more complex components, such as e.g. a vacuum chamber allows. In addition, functional components can already be realized in the manufacturing process. The integration of a system of flow channels directly into the wall of a chamber is just one example. Thus, such a chamber can be heated during evacuation and effectively cool in later operation.     

真空镀膜在高阻隔性包装材料上的应用

高阻隔性包装材料在食品、饮料、生鲜、药品、电子产品、化工等行业具有广泛的应用。真空镀膜技术生产制备高阻隔陶瓷膜包装材料是近期全球包装材料工业的热点,本文将简要介绍市场上主要的高阻隔性包装膜产品,并对真空镀膜方法生产高阻隔性包装材料的相关工艺技术进行了详细的探讨。     

Design of the vacuum system for Diamond, the UK third generation light source

The Diamond synchrotron, which is due to come into operation with beam for users in 2007, is being constructed at the Rutherford Appleton Laboratory, Oxford. The design status of the vacuum system of the storage ring as at 31st December 2002 will be reported.Diamond is based on a 24 cell 3 GeV electron storage ring of 561.6 m circumference. As is the case for most such machines, the operational pressure has been specified as 10⁻⁹ mbar to give a beam lifetime >10 h at the design current of 300 mA. The storage ring vacuum system will use conventional technology and most of the vacuum vessels will be constructed of stainless steel. With the exception of the insertion device (ID) vacuum chambers, the ring has not been designed to be baked in situ, but all components will be vacuum baked as sub assemblies before installation. The vacuum system is designed to achieve the required pressure after 100 A h of beam conditioning using the pumping scheme, which will be described.Twenty-one ID straights are available for ID, of which seven will be installed at the start of operations. Three types of vacuum vessel will be used in these straights, a stainless-steel make-up pipe, a NEG coated narrow-gap vacuum chamber for conventional IDs and a wider vacuum chamber to house in vacua IDs. The ID straights have an isolation valve installed at each end, and in situ baking can be used in these restricted locations, for example to activate the NEG coatings.The vacuum system for the beam line front ends has been designed to provide good vacuum isolation between the storage ring and the experimental beam lines, whether or not an interposing window is fitted.Pumping schemes, pressure measurement and calculated pressure profiles will be described.     

机械真空泵远程故障诊断系统研究与应用

真空精炼炉是一种用于生产高品质钢水的二次冶炼装置,其核心是机械真空泵系统.该系统能否长期稳定运行将直接影响到钢水冶炼效果和吨钢成本,因此对该系统进行在线监测和快速故障诊断尤为重要.本文以RH真空精炼炉为例,将各级机械真空泵与多种监控设备耦合,并引入远程物联网技术,创建了远程故障诊断系统,并得到国内某钢厂实践验证.     

合金熔剂精炼法制备太阳能级硅的研究进展

冶金法作为制备太阳能级硅的低成本技术,受到了光伏行业的广泛关注。其工艺主要包括酸洗、造渣、定向凝固、真空精炼、熔剂精炼等。其中,熔剂精炼由于操作温度低、杂质去除效率高,被视为最有可能实现大规模产业应用的低成本冶金技术之一。近年来,熔剂精炼法提纯太阳能级硅的研究发展迅速,科研工作者已经较系统地研究了Si-Al、Si-Sn、Si-Cu、Si-Fe、Si-Ca等不同合金熔剂体系杂质从硅中去除的行为和规律。综述了国内外学者利用不同合金体系去除冶金级硅中杂质的研究结果,特别关注了硅中杂质B、P的去除,同时也对熔剂精炼过程中熔剂金属与初晶硅的分离进行了概述。最后,指出了熔剂精炼提纯冶金级硅有待进一步深入研究的方向。     

Improvement of beam lifetime and vacuum system of the PF-AR

Successive improvements have been performed on the vacuum system for the Photon Factory Advanced Ring (PF-AR) at the High Energy Accelerator Research Organization (KEK). The main purpose is to prolong electron beam lifetime for stable operation as an intense pulsed X-ray source. In the past three years, a total of 61 sputter ion pumps (SIPs) were additionally installed, and the increased effective pumping speed amounts to 13% of total. Comparison between calculated and observed beam lifetimes indicates that the lifetime is restricted mainly by the residual gas scatterings and that improvement of the vacuum will realize still longer lifetime. Sudden beam lifetime drops caused by dust trappings have been investigated for many years. The frequency of the lifetime drops has decreased as operation time elapsed after a large-scale reconstruction. Effect of distributed ion pumps (DIPs) on the lifetime drops has also been investigated experimentally.     

钼酸铅晶体表面红外增透膜的研究

本文讨论了用于钼酸铅晶体表面的宽带红外增透膜的设计以及其在真空环境中的制备。膜系设计中 ,运用反射率图解法以获得满意的光学性能 ;与传统的热蒸发镀膜工艺相比 ,在真空沉积过程中采用了离子辅助沉积技术 ,从而大大提高了膜层的光学特性及膜层品质。试验表明所镀膜层性能优异 ,在光纤通信领域具有广阔的应用前景