针布齿条的低温渗硼实验研究

详细讨论了针布齿条氮基气氛外层保护低温渗硼的实验方法、设备及工艺流程。通过对渗硼荆、渗硼工艺及其渗硼层特点的分析，指出了采用该工艺渗硼可使针布齿条试样具有渗层致密均匀（层厚10v．m）、齿部硬度高（1290HV）、表面粗糙度值较低等优异的综合性能，且具有冲齿齿廓清晰，齿顶、齿棱、齿角锋利，齿部无卷刃和毛刺等特点。     

固体渗硼在烟枪零件上的应用

小压板是烟枪的主要零件,几何形状复杂,厚薄尺寸又很悬殊,采用渗碳淬火工艺往往不能达到表面具有高硬度和耐磨性、而心部又要有良好的塑性和韧性的要求。我们采用表面固体渗硼的工艺代替固体渗碳淬火工艺,取得了良好效果。     

烟枪固体渗硼 提高寿命三倍

烟枪是卷烟机上的易磨损件,常德卷烟厂以往一直采用传统的表面渗碳淬火工艺处理,其使用寿命短,且每换一次要停机两小时。而采用固体渗硼新工艺处理,虽然每支热处理费增加6元,但使用寿命     

针布齿条热处理探析

通过对齿条热处理特别是淬火工艺问题的探讨，提出应加强对热处理特别是针布用合金材料热处理工艺的研究，提高对淬火火焰、加热温度及常见缺陷的认识，优化淬火工艺，将有利于保证齿条质量，改善齿条耐磨性。     

渗硼工艺提高造锁模具寿命的研究

采用渗硼淬火工艺对造锁模具进行强化，提高模具抗磨料磨损的能力。结果表明，用该工艺能使模具平均提高两倍以上。     

低碳钢塑料模具的渗硼质量分析

对低碳钢塑料模具进行了固体粉末渗硼处理,研究了所获渗硼层及基体的金相组织,对其渗硼层进行了硬度分析,并在生产实践中对渗硼后的模具进行了工艺寿命实验。结果表明：在本实验工艺条件下,模具表层的硬度得到了较大的提高;但所获渗硼层组织薄,且不连续。经生产实践证明,渗硼后的渗硼层质量未达到规定要求,其使用寿命未达到预期目标。针对渗硼层的上述质量问题,本文提出了对渗硼工艺的一些改进措施。     

Q235钢渗硼层组织缺陷金相分析

对制砖机模板用Q235低碳钢进行了固体粉末渗硼处理。利用光学显微镜和显微硬度计对渗层组织进行了金相观察和渗硼层硬度分布测试。分析了渗硼层组织中的缺陷。结果显示渗硼层组织中的缺陷主要有：渗硼层过薄；渗硼层生长不连续：渗层中有裂纹、孔洞、硼齿分叉及渗硼层组织疏松等，另外还观察到呈不连续状态的硼化物生长现象。为提高渗硼质量，避免渗硼层组织缺陷。本文提出了一些相应的缺陷控制措施。     

渗硼处理提高塔轮寿命研究

渗硼工艺是一项新的表面硬化技术。用渗硼工艺制造的塔轮其寿命可提高２５～３倍。渗硼工艺参数包括加热温度Ｔ＝９００℃，加热保温时间６ｈ。渗硼层深度为０１４～０２ｍｍ，表层ＨＶ＝１４４８～１８９２，过渡区ＨＶ＝６２５～１０４８。     

针布齿条的淬火工艺研究

综述了国内针布齿条制造业现状,从加热温度、保温时间和淬火冷却速度等方面,探讨了淬火工艺选择的影响因素,重点分析了针布齿条的火焰加热淬火工艺的诸多注意事项及质量缺陷与成因,并提出采用在线高频预热技术、安全环保高热能燃料等几点可行性建议.     

激光技术在金属针布齿条淬火中的应用

为了提高金属针布使用寿命,从激光淬火硬化层形成机理、传热及激光淬火硬化层特性两部分阐述了激光淬火的基本原理,详细介绍了自主设计的金属针布齿条激光淬火试验定位装置的设备参数、装置设计及试验方法,通过对金属针布齿条进行激光淬火试验,测定其齿尖硬度、金相组织,并与火焰淬火进行对比。指出:激光淬火试验装置定位精度可达0.03mm,相比火焰淬火采用激光淬火后金属针布齿条第1点硬度值提高约6%,第2点硬度值提高约17.9%,且可控性较高,淬火质量更加均匀稳定;激光淬火使金属针布齿条齿尖硬化层组织得到细化,晶粒平均直径约2μm,优于平均直径约为15μm的火焰淬火晶粒;激光淬火工艺可节约可燃气体和淬火油,淬火过程基本无环境污染,应用前景较好。     

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