变频技术在全电子细纱机中的应用

为了解决电网短时供电异常时,变频器失电失压使全电子细纱机运行失控,造成细纱断头、捻度突变、管纱形状变化等问题,分析了全电子细纱机的控制原理和出现相关问题的原因,并详细解析了定制款日立SJ700-C系列变频器在全电子细纱上的应用以及在电网异常时电控系统的自我解决办法;同时也简析了紧密纺和集体落纱系统中变频技术的应用和注意事项。指出:变频技术的自我完善是保证全电子细纱机正常使用的重要保障,也是变频技术逐渐替代伺服系统的必由之路。     

四象限变频器在采煤机中的应用探讨

电子信息技术的快速发展为采煤机的设计完善提供技术保障,以采煤机应用的交流变频牵引为例,其在实际操作中多用于坡度平缓煤层,许多大倾角工作无法利用该类采煤机完成。在此背景下便提出四象限变频器的引入,其以自身的优势被广泛用于现代煤炭生产中。文章主要对四象限变频器应用的优势以及采煤机变频器应用下的震动故障问题与相应解决策略进行探析。     

应用于造纸机传动系统变频器的参数分析和设置

变频器作为造纸机变频传动控制系统的核心装置,其性能应用的优劣对整个纸机系统将产生较大影响。就造纸机变频传动控制系统中常用的几类变频器的应用参数给出相应的分析及设置参考。     

变频节能技术在制糖工业中的应用综述

从变频器的原理和国家"十二五"制糖工业节能目标要求出发,介绍制糖工业中应用德国西门子AFE整流回馈单元的甘蔗起重节能应用,阐述制糖分蜜变频节能系统中的SINAMICS120变频器的配置,以及压榨系统的交流变频器与直流调速节能效果对比,并提出大力推广变频节能技术的重要性。     

煤矿主扇风机上变频技术的应用

主要介绍了变频技术的发展过程及现状,变频调速运行和节能原理,变频技术在煤矿主扇风机上的应用和变频器的选用原则,并对变频技术在煤矿机电设备上的应用进行了展望。     

变频器在纸厂给水站上的应用

介绍了变频器的基本概念及其发展史;变频调速装置的节能原理;着重讨论了变频器在给水站一泵房供水泵开环控制方式上的应用及二泵房供水泵闭环控制方式恒压供水上的应用。实践证明变频调速技术的应用是造纸行业节能减排重要措施之一。     

变频器在造纸厂供浆泵中的应用

简述了变频器及调速的工作原理,介绍了变频器在造纸厂供浆泵改造中的应用,由原来人工阀门控制改为由变频器自动调速控制的变频改造方法。     

合格介质泵的调速分析及实现

简述了高压变频器在工业生产中的的必要性,高压变频器在姚桥矿选煤厂介质泵调速控制中的应用,以及变频技术应用后带来的良好经济效果。     

纺织智能变频器在细纱机上的应用

为了降低细纱断头,减少纱线毛羽,根据变频技术在细纱机上的应用原理,重点对纺织智能变频器在细纱机上的应用作了介绍,并对普通细纱机与变频细纱机的纺纱断头率及毛羽进行了对比分析.结果表明:应用纺织智能变频器可以降低细纱断头,提高单产,改善成纱质量.     

艾默生工业自动化（中国）获变频器行业三项品牌大奖

2008年1月中旬,在由《变频器世界》和中国自动化网举办的“2007年度中国变频器行业年度评选颁奖大会”上,国际知名变频器品牌——艾默生工业自动化（中国）（简称艾默生IAC）一举荣获“2007年度中国低压变频器市场十大国际品牌”、“2007年度中国变频器应用电梯行业主流品牌”、“2007年度中国变频器应用市政行业主流品牌”三项大奖。本次评选活动主题为“打造诚信品牌,发展变频产业,构建和谐社会”。旨在肯定和鼓励为中国变频传动事业做出贡献的优秀变频器企业,推动变频器行业持续健康发展。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the