海德堡胶印机常见故障分析及排除

故障1纸张到达前规,整台机器停机 分析:此故障主要是纸未走好及光孔未调整好造成的. 故障原因1:纸张到达前规时间过早或过晚. 排除方法:点动机器使纸张走到前规处,查看前规回程定位并下落至最低点时,纸张距前规距离是否为4～5mm.如未到5mm,则走纸过慢;反之则走纸过快.可松开操作面两个φ13mm螺母,借助法兰盘调至标准位置.     

采用热管气体射流冲击技术干燥香菇

采用热管气体射流冲击技术,通过单因素试验研究鲜香菇的干燥工艺,以香菇干燥成品的复水比、感官评价及能耗变化为试验指标,确定干燥温度、热风风速、喷嘴距物料高度的最佳工艺参数。结果表明:香菇气体射流冲击适宜干燥工艺参数为干燥温度60℃、风速40 km/h、喷嘴距物料的高度115 mm。     

双锥面熔体微分静电纺中电场分布的有限元分析

为获得最佳的熔体微分静电纺丝结构参数,采用有限元分析软件ANSYS对多层锥面无针熔体微分静电纺丝中的电场分布进行模拟,分析了双锥面特征设计参数对纺丝尖端场强的影响,分别讨论了内圈直径和内圈伸出距离对内外圈纺丝尖端及纺丝路径场强分布的影响。ANSYS数值模拟结果表明:增加锥面层数会减弱最外圈纺丝尖端的电场强度;对于双锥面熔体纺丝装置,内锥面直径大小对纺丝尖端场强分布的影响不明显;当内锥面伸出距离增大时,内外圈纺丝尖端场强的差值先减小再增大;当内锥面直径为26 mm,内圈伸出距离为6 mm时,内外圈纺丝尖端电场强度分布最相似,能够保证内外锥面制备的纤维射流间距相同,实验结果和模拟结果一致。     

小麦粉品质与南方馒头品质关系的研究

选择25种筋力不同的商用小麦粉,分析其主要品质参数及制作的南方馒头质量,研究小麦粉品质特性与南方馒头品质的关系。结果表明,面粉湿面筋含量、灰分含量、粉质和拉伸指标与南方馒头总评分有较明显的相关性。实验证明,适宜制作南方馒头的小麦粉属于低弱筋粉,建议面粉品质指标:湿面筋含量≤25%,灰分≤0.56%,白度≥80,粉质仪吸水率≤56%,稳定时间≤2.0min,拉伸仪延伸度≤110mm,拉伸阻力480～630EU。     

液相色谱-高分辨串联质谱法测定奶粉中A2β-酪蛋白及β-酪蛋白与乳清蛋白含量关系的研究

目的:建立奶粉中A2β-酪蛋白分离定量的液相色谱-高分辨串联质谱法,并利用婴儿配方奶粉中酪蛋白、乳清蛋白和总蛋白含量的关系,间接得到乳清蛋白含量。方法:样品经前处理后,采用ACQUITY UPLC HSS T_(3)柱(100 mm×2.1 mm×1.8μm),0.1%甲酸-水和乙腈为流动相,梯度洗脱分离。多反应离子监测模式定量测定其中的A2β-酪蛋白特征肽。结果:在0.02~2.0μmol/L范围内线性关系良好(r=0.9938)。在低、中、高三水平加标试验中,回收率在94.9%~98.7%,相对标准偏差在1.7%~3.7%,检出限为0.80 mg/100 g,可满足对奶粉中A2β-酪蛋白定量要求。采用该法对市售11批声称A2奶粉和18批未声称A2奶粉(以下简称A2奶粉和普通奶粉)中A2β-酪蛋白进行测定。结论:A2奶粉中A2β-酪蛋白占总β-酪蛋白含量的86.2%~98.7%,而普通奶粉则低至20.0%~50.0%。另外,乳清蛋白含量的间接测定值和理论计算值经统计分析,无明显差异(P>0.05),为分析婴儿配方奶粉中乳清蛋白含量是否符合国标要求提供参考。     

意大利质量手册介绍(续)

(上接2005年第21期)表13染色皮革-基本要求条件基本要求条件测试方法规格要求耐揉色牢度(这里指出的是标准规格要求,建议家具制造厂家附上用户指南,说明皮制家具保养维护方法,以及可能发生的各种情况。)ISO11640-ISO11641皮革色泽变化和絮衬材科被染色(国际灰度表):干,500次:≥4;湿,250次≥3/4;浸汗,80次≥3/4耐光色牢度ISO105-B02蓝度表:≥5涂饰层附着力ISO11644≥2N/10mm(干式处理后附着力)抗撕裂强度ISO3377-1≥20NpH及ΔpH ISO4045≥32-如pH为<4,ΔpH≤07表14特别条件(测试方法及规格要求)特别要求条件测试方法规格要求对火焰…     

间歇式微波灭菌干燥设备

由上海某微波设备有限公司生产的间歇式微波灭菌干燥设备,采用先进的微波技术,对医药、食品等领域的粉状、颗粒状、块状及液体等物料分批进行低温灭菌和干燥处理. 该设备采用角锥型喇叭天线和多孔微波传输技术,其存料筒可自动搅拌,使物料处理更均匀. 该设备还可专为配置物料处理显像功能.温度自动控制及显示功能,自动定时和报警工能.设备占地面积小、无噪声、操作简单及维修方便,符合制药机械GMP的要求.该设备获国家实用新型设计专利. 主要技术参数 型号 JWYM1 -1A JWYM1 -2A JWYM2 -3A JWYM2 -4A 工作频率(MHz) 915±50 915±50 2 450±50 2 450±50 输出功率 (kW) 20 40 7.2 9 微波泄漏(mW/cm2) ≤5 ≤5 ≤5 ≤5 灭菌产量(kg/h) 90 180 34 42 干燥水量(kg/h) 10 20 3.6 4.5 外形尺寸(m) 2×1.2 1.8 2×1.5 1.8 1.5×1.2 1.7 1.7×1.2 1.7 CP011214 柴田式粉碎机 由天津市某制药机械厂生产的F-400柴田式粉碎机,适用于粮食、饲料、化工原料、中西药、煤粉、生铁粉等物料的粉碎加工,特别对于纤维性强的物料有明显的效果. 主要技术参数 主轴转速(r/min):3 500 风机排风量(m3/h):1 238 粉碎细度(目):40～120 生产能力(kg/h):25～180 配套电机:2～220kW (Y180M) 外形尺寸(mm):1 200×600×750 整机质量(kg):800 CP011215 系列电机振动垂直输送机 由河南省新乡市某振动机械厂生产的系列电机振动垂直输送机,适用于一切粘度不大的颗粒状、块状、粉状及短纤维的固体物的输送.并具有从下向上或从上向下输送物料的功能,按不同的生产工艺要求可制成敞开式或封闭式结构.根据用户需要,改变本机结构,可以在输送物料的同时,完成如冷却、干燥及筛分等工艺过程. 该机可广泛用于食品加工、粮食、农牧、化工、冶金、塑料、轻工及制药等行业用作提升物料的设备.该机特点:设计结构简单、安装使用维护方便、能耗小、占地面积小、节省投资、密闭输送能防止有害气体和粉尘逸散. 主要技术参数 型号 SZC-1250 SZC-2000 SZC-3500 SZC-4500 提升高度(m) 1.25 2 3.5 4.5 输送量(t/h) ～0.3 ～0.6 ～3 ～4 功率(kW) 2×0.1 2×0.2 2×0.75 2×1.5 电压(V) 380 380 380 380 额定电流(A) 2×0.4 2×0.8 2×2.3 2×4.6 整机质量(kg) 120 317 1 150 1 260 CP011216 气动定量充填机 由石家庄市某食品机械有限公司生产的QCT12型气动定量充填机,其特点:设计合理、定量准确、操作方便.该机既可单独使用,又可与气动双卡结扎联机使用.可完成肠类食品定量的或不定量的灌装生产工序. 主要技术参数 料斗容量(L):64 最大充填量(L/次):1.25 气压(MPa):0.7 净质量(kg):152 充填速度(次/min):35～20 充填管至地面距离(mm):850～900(可调) 外形尺寸(mm):720×638×1 410 定量调节范围(L/次):0.12～1.25     

电气化铁路接触网补偿钢丝绳的设计与生产

介绍电气化铁路接触网的技术要求和组成,接触网补偿用钢丝绳的材质与结构,接触网补偿钢丝绳尤其是不锈补偿钢丝绳的技术要求,以及我国接触网补偿用钢丝绳的研发状况,要求高碳钢及不锈钢补偿绳疲劳试验后的整绳破断拉力与规定值相比下降分别不超过10%和5%。以12×7+12×3+12×3+1×19W—9.1为例,介绍接触网补偿用钢丝绳的研发:利用串联式变形器一次合绳,钢丝绳为右交互捻,捻距倍数为6.8倍;中心股、内层股、次外层股、外层股的捻距分别为16.8,5.27,.81,7.005mm,直径分别为2.40,.8,1.2,1.79mm,并根据各层股的捻距倍数和捻制系数计算出各层股丝的直径。     

大桥斜拉索制造关键技术研究

大桥用镀锌钢丝必须同时满足扭转≥8次,松弛率≤2.5%,抗拉强度≥1 670 MPa。介绍大桥斜拉索用镀锌钢丝和斜拉索制作工艺。选用宝钢B82MnQL盘条生产7.0 mm镀锌钢丝,锌层面质量≥300 g/m2。镀锌钢丝生产过程中应提高钢丝表面质量、直线度及镦头性能。降低斜拉索索体扭转的方法:改进绞制与挤塑工序牵引方式;改进绞制弯道以保持斜拉索绞制节距稳定;改进索体绕包张力。对新型斜拉索密封体系进行研发。斜拉索疲劳性能改进措施:提高镀锌钢丝表面质量均匀性、直线性和直径精度。生产的镀锌钢丝斜拉索经检验和使用,能够满足用户的特殊要求。     

固定床颗粒层除尘实验研究

针对高温除尘中细微粉尘的脱除难题,设计了固定床颗粒层除尘实验台,在常温下进行除尘实验.实验结果表明:颗粒层除尘效率与过滤介质粒径、过滤层厚度、过滤时间以及过滤速度有关;减小过滤介质粒径、降低过滤风速、增加床层高度都使细微粉尘的脱除率有一定提高.本实验条件下最佳过滤层厚度为100 mm,过滤风速0.4 m/s,介质颗粒粒径为0.9～1.2 mm.优化后的颗粒层除尘器除尘效率最高可达99.8%.     

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