金刚石初始粒径对金刚石聚晶层形貌及表面残余应力的影响

在高温高压条件下（5.2-5.6 GPa,1350℃-1450℃）,以镍基合金为烧结助剂采用熔渗法制备了金刚石复合片（PDC）。采用SEM考察了不同金刚石微粉粒径制备的金刚石复合片中金刚石聚晶（PCD）的组织形貌。通过Raman光谱利用静水压应力模型表征了PCD层表面应力。结果表明,PCD层形成了致密的交错生长结构;PCD层表面残余应力表现为压应力并随着初始金刚石微粉粒径的增大而增大,其值为0.12-0.22GPa。     

热稳定金刚石聚晶的制备及表征

在高温高压条件下（5.6GPa,1200℃～1480℃）,以含硼金刚石微粉为原料,镍基合金为烧结助剂,采用熔渗法成功制备了热稳定金刚石聚晶（Thermally stable PCD）。通过X射线衍射（XRD）和扫描电镜（SEM）,研究了烧结温度对热稳定金刚石聚晶的物相成分、微观组织形貌的影响;并与普通金刚石聚晶进行了差热（DTA）、热重（TG）的对比分析测试,结合X射线光电子能谱（XPS）测试结果给出了相应解释。实验结果表明：在压强为5.6GPa条件下,温度在1300℃～1450℃区间内,才能实现热稳定PCD的烧结;此时形成的热稳定PCD的耐热性和抗氧化性相比普通PCD均有较大幅度提高。     

镀钛金刚石制备金刚石聚晶的研究

在国产六面顶高压设备上,以镀钛金刚石为原料,镍基合金为烧结助剂,采用熔渗法成功制备了金刚石聚晶（PCD）,通过扫描电镜（SEM）、X射线衍射（XRD）、拉曼光谱（Raman）等测试方法,研究了不同烧结压力和温度对镀钛金刚石聚晶组织形貌的影响,与普通金刚石聚晶进行了物相成分及残余应力的对比分析。实验结果表明：烧结条件为5.4-5.6GPa,1350℃-1450℃下的镀钛PCD具有较高的致密性和机械性能;镀钛PCD的衍射峰中有NiMnCo、碳化钛和TiMnC化合物。镀钛PCD相比普通的PCD表面残余应力略大。     

SiC涂层对金刚石刀头性能的影响

探索了在金刚石表面镀覆SiC涂层的工艺方法,并以机械合金化铁合金粉末为基体,采用热压烧结工艺制备了长条形金刚石刀头,测试分析了刀头的硬度、抗弯强度和微观组织。结果表明：用金刚石＋Si＋I2混合粉末（工艺A）、或金刚石＋聚碳硅烷（PCS）溶液（工艺B）于1000℃～1200℃真空反应,均能在金刚石表面制备出SiC涂层;在基体中添加Zn、Sn等低熔点元素,会降低刀头的硬度和强度;而添加少量B4C,可以起弥散强化的作用;对金刚石先镀Ti、再镀SiC,可使刀头的硬度和强度进一步提高,最高硬度为HRB118,抗弯强度为543MPa。     

钎焊金刚石取孔钻的制备及其钻削性能研究

由于金刚石与钎料合金之间高的结合强度以及高的金刚石出刃,钎焊金刚石工具比电镀和烧结金刚石工具拥有更优异的加工性能。使用钎焊法分别制备了单层和多层金刚石取孔钻,通过对硅酸盐玻璃的钻孔实验,对比了单层金刚石取孔钻和多层金刚石取孔钻的使用寿命及加工效率。结果表明：钎焊多层金刚石取孔钻的寿命是单层取孔钻的3倍,但其加工效率比单层取孔钻略低。通过扫描电镜（SEM）对两种取孔钻失效后的表面微观形貌进行观察,发现金刚石与钎料之间具有很高的结合强度,钎焊多层金刚石取孔钻在加工过程中能够实现金刚石的连续出刃。     

机械合金化Fe基预合金粉末对金刚石刀头性能的影响

探索了Fe-Cu-Ni-X（X=W、Mo、Ti、C、B4C）系粉末的机械合金化工艺,及其对热压烧结金刚石刀头强度和硬度的影响。发现干法球磨20小时可以得到15μm的预合金粉末,除W、B4C之外,其它元素均可固溶入Fe中;经930℃热压烧结后,Cu又从Fe中析出,同时形成WC等硬质相;B4C可能在球磨过程中产生了部分非晶化,经高温烧结后又恢复了结晶态,B4C并未与W、Mo、Ti等合金元素反应形成金属硼化物;将80vol%机械合金化预合金粉末与20vol%的45/50#镀Ti金刚石颗粒均匀混合后,进行930℃热压烧结,随着B4C含量增加,金刚石刀头的硬度逐渐增大,而抗弯强度在1%B4C时达到最高值949MPa,硬度为HRB120.7。     

金属粉料预压块的还原处理对金刚石工具胎体性能的影响

以铁基粉末为金刚石工具胎体材料,采用＂预压-还原-热压烧结＂和＂预压-热压烧结＂工艺制备烧结体。采用氧含量测定仪检测了预压块和还原块的含氧量,采用扫描电子显微镜（SEM）观察了烧结体的微观形貌,研究了铁基粉末预压块的还原处理对胎体体积密度、洛氏硬度、抗弯强度和耐磨性等性能的影响。试验结果表明：经过还原处理后,还原块的氧含量明显降低,获得的烧结体组织更加致密,其性能也优于未处理过的。     

高温高压下Fe-Ni-C系合成金刚石单晶的机理研究（上）

从三个方面综合介绍了本课题组近几年来采用Fe-Ni-C系在高温高压下合成优质金刚石单晶的研究成果：1）采用单质金属铁、镍粉和石墨粉以及粉末冶金方法制备出新型铁基触媒,利用六面顶压机合成了高品位的金刚石单晶;2）采用现代分析测试方法对金刚石单晶外的金属包覆膜物相结构进行了系统表征和分析;3）基于固体与分子经验电子理论（EET理论）和托马斯-费米-狄拉克-程开甲理论（TFDC理论）对金刚石合成过程中相关物相（金刚石、石墨、Fe3C（（Fe,Ni）3C）和γ-（Fe,Ni）等）的价电子结构进行了计算和论证。实验分析与理论研究结果表明,单质金属粉辅以粉末冶金方法同样可以实现高品位金刚石单晶的合成;金属包覆膜中存在大量的Fe3C、（Fe,Ni）3C类型的金属碳化物和γ-（Fe,Ni）型金属中间相,且γ-（Fe,Ni）与金属碳化物的对应晶面之间存在相互平行的位向关系;金刚石与石墨主要晶面间的平均共价电子密度在一级近似条件下均不连续,而Fe3C与金刚石或Fe3C与γ-（Fe,Ni）之间存在界面电子密度连续性,因此证明Fe3C/金刚石界面能够满足金刚石生长的边界条件。研究结果表明,金刚石单晶生长的碳源并非直接来源于石墨,而来源于在金属中间相的催化作用下,由金属碳化物过渡相中脱溶出的、具有类SP3杂化态的C-C原子团,因此从实验和理论上进一步支持了金刚石合成的＂溶剂-催化＂理论。     

聚晶金刚石复合片钻头失效形式

兖州矿业（集团）公司机电设备制造厂通过对聚晶金刚石复合片（PDC）钻头失效形式及相关工艺过程研究，总结出了PDC钻头加工使用过程应该注意的问题，对提高PDC钻头加工水平及延长使用寿命有一定借鉴意义。     

金刚石钎焊（上）

金刚石磨料主要靠机械夹持力把持在金属（烧结或电镀）胎体中。由于这一弱点,在切割过程中,金刚石不可避免地会从胎体中脱落或掉出。此外,金刚石突出高度较低,故金刚石工具的切割速度受到限制。而且,金属胎体和工作对象（被切割岩石）相互磨擦,将会导致金刚石和其它材料的热损伤,而且工作的功率消耗将增加。金刚石采用钎焊的办法牢固地把持在金属胎体中,可形成强力的化学结合,金刚石磨料的突出高度将成倍提高,而不会从胎体中脱落或碎裂。因此,金刚石工具的切割速度将会成倍提高。当钎焊料熔融时,碳化物形成物将向金刚石方向迁移而在界面上形成碳化物。这种反应可能过分而使金刚石质量明显下降。此时,可能需要对金刚石进行镀覆以便缓和与控制这种反应。当金刚石钎焊在基体的表面时,熔化趋向于将金刚石聚集在一起,可促使钎焊层局部加厚。这种金刚石晶粒的成簇聚集将降低金刚石工具的切割效率。一种金刚石矩阵有序排列设计（grid）是必要的,它可保持钎焊层具有均匀的厚度。因此钎焊合金可控熔融,可使每一粒金刚石晶体周围形成较缓的坡度。这种整体均匀焊层的支承可使金刚石工具高速有效切割,而功率消耗较低。     

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