四步法十字形三维编织物的工艺研究

十字形三维编织物是三维编织异形件中的一种。主要研究了一种四步法十字形三维编织物的编织工艺,该工艺不同于变截面的增减纱工艺,纱线贯穿织物始终,无断纱头存在织物中。     

异形热成型包装件仿形裁切机构研究

为实现异形热成型包装件的准确分切,研究异形新型裁切工艺过程与仿形裁切机构。通过分析异形包装件的外形轮廓和裁切要求,确定了裁切的工艺过程和裁切刀的运动轨迹。选定相应的执行机构,并对仿形裁切机构进行参数化设计。采用可实现运动轨迹的凸轮-连杆机构带动裁切刀进行仿形裁切;采用解析法对执行机构进行参数化分析计算,找到固定凸轮与连杆的几何关系,最终确定执行机构关键部件固定凸轮的外形轮廓。采用仿形裁切方法可以实现异形热成型包装件的有效分切,本研究可为异形件裁切系统的设计提供参考。     

异形中长纤维织物结构设计

本文通过试验对比和理论分析,探讨了以混用不同异形中长纤维为原料制成织物时,对织物风格、性能、经纬密配置、组织结构、耐磨性、弹性、起毛起球性、硬挺度、膨松度和染色后色档等的关系,可供采用异形纤维,开发新产品时作参考。     

含沟槽异形PET丝性能研究

选用了五连环形、U形、三叶形、十字形四种含沟槽不同截面形态异形PET丝,并作为对比选用了扁平形PET丝,测试分析了纤维的纵横形态特征、拉伸性能、回潮率、沸水收缩率以及表面浸润性能。试验结果表明:纤维异形及其异形程度大小对丝线的拉伸断裂强度、回潮率等影响不大;纤维径向沟槽结构显著影响其沸水收缩率及动态接触角,且纤维异形度对纤维性能影响的贡献优于纤维沟槽数量。     

T形截面三维编织复合材料细观结构分析及弯曲性能预测

根据矩形组合截面三维编织复合材料四步法编织原理,分析了T形截面编织物的纱线运动规律,按照载纱器的水平运动规律确定了纱线的空间运动轨迹,并用控制体积法建立T形截面交接区域的特殊细观结构模型。在假设纱线截面为椭圆形等理想状态下,建立了编织工艺参数之间的数学关系。运用弯曲刚度合成法预测了T形截面三维编织复合材料的弯曲性能,用MatLab编写了弯曲模量的计算程序。结果表明：弯曲模量随编织角的增大而减小,随纤维体积含量的增加而增大,三维五向T形截面梁的弯曲性能优于三维四向的。最后将预测结果与实验结果进行比较分析,结果证实用弯曲刚度合成法预测T形截面三维编织复合材料的弯曲性能是可靠的。     

超细异形腈纶混纺纱织物的性能研究

为研究超细异形腈纶混纺纱织物的性能,以新型超细异形腈纶、黏胶、莫代尔、棉、桑蚕丝等为原料,设计织物规格并按不同成分比例试制了7种织物。然后对试制织物的吸湿性、透气性和保暖性能进行测试和数据分析,结果表明:超细异形腈纶的双"T"形横截面结构使织物蓬松,柔软;在超细异形腈纶与黏胶的混纺纱中,在一定范围内随着腈纶纤维含量的增加,保暖性增强;与莫代尔、棉相比,黏胶较适合与超细异形腈纶纤维混纺,开发的面料具有较好的吸湿、透气和保暖性。     

基于ANSYS新型退卷机T形台结构设计

为使新型退卷机中承载接布作用的T形台最大挠度在最大载荷下小于0.5mm的标准要求,首先以T形台三维原理图为基础,利用ANSYS软件对T台结构在理想载荷下模拟仿真;通过机械结构应力应变结果图可看出T形台上板面最大应力沿中心对称面向两边逐渐变小,T形台竖板面最大应力分布在两个滑块以及竖板面与加强筋板的低端接触的点位.根据此结果,分别拟定了三种改进方案,一是竖板面前与上板面之间加一块筋板;二是竖板面后与上板面之间加两块筋板;三是前面加两块筋板,后面加一块盘板.利用ANSYS软件对这三种结构进一步仿真后,发现第三种方案可使T形台的最大挠度降为0.219mm.     

异形截面预制件编织的置换分析

通过实例,应用置换理论分析了矩形三维预制件的编织过程,在将编织循环表达为不相交的轮换的乘积后,建立了各轮换与编织锭子移动规律之间的关系。以口字截面预制件编织为例,对异形截面三维预制件的编织过程进行了置换表达。从不相交的轮换的积的表达式中,不仅可以得到有关异形截面三维预制件编织锭子移动规律方面的特性,还可判别出方格阵上编织锭子的类别并确定其初始位置,为异形截面三维预制件编织的最终实现奠定了基础。     

织物结构的多项式数学模型与三维模拟

在Peirce模型的基础上,利用多项式曲线拟合的方法模拟纱线的屈曲形态,以纱线弯曲的曲率、经纬纱线的半径、几何密度、屈曲波高来计算纱线屈曲轨迹上的每个点,再通过经纬纱线的排列来展示织物的结构图.在VC 6.0开发环境下,按照多项式数学模型,利用OpenGL图形技术实现了平纹和斜纹织物结构的三维模拟.模拟时,能对图形进行移动、旋转、缩放等图形定位操作;能改变一个或几个结构参数,展现经、纬纱在织物中的屈曲交织形态,并瞬时显示改变后的三维图形;通过改变法线向量的求法,改变织物结构模拟的光照效果.     

用图像处理技术快速检测机织物的经纬密度

文章讨论了用一维傅立叶变换、二维傅立叶变换和小波变换等图像处理技术检测织物经纬密度的原理和方法,找到了一种快速、可靠的织物经纬密度的检测方法.用VC 编程实现了织物经纬密度的快速检测,并用三维立体图表示出织物图像的变换结果.     

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