模切机双肘杆机构运动分析与优化设计

为了研究模切机双肘杆施压机构的运动规律,基于回路法对双肘杆施压机构进行运动建模,并对其进行数值求解.利用MATLAB语言进行运动仿真,绘出双肘杆机构运动仿真曲线,并进行运动特性分析.在仿真分析的基础上建立数学模型,并进行优化设计,对优化前后各构件参数进行了对比,改善了双肘杆施压机构的运动性能.     

气囊织物平缝机刺料机构的运动分析

针对气囊织物平缝机刺料机构的特点,完整地绘制了运动简图,并对此运动简图进行了等效代换.提出了刺料机构运动特性分析方法,推导了位移、速度、加速度等运动方程,得到了关键参数对刺料机构运动特性的影响,为机构进一步优化设计建立了理论基础.     

挠性剑杆织机球面曲柄传剑机构的分析

本文探讨了挠性剑杆织机球面曲柄传剑机构的运动规律和运动特性;综合分析了机构参数对剑杆运动的影响及和引纬工艺参数间的关系,给出了参数选取的综合方程式。     

复动式全开口提花机刀箱传动机构分析

本文应用解析高级机构的方法计算出复动式全开口刀箱传动机构的运动规律,综合分析了机构运动特性、机构调节参数对开口工艺参数的影响及相互间的数值对应关系。     

复动式全开口提花刀箱传动机构分析

本文应用解析高级机构的方法计算出复动式全开口刀箱传动机的运动规律，综合分析了机构运动特性、机构调节参数对开口工艺参数的影响及相互间的数值对应关系。     

新型剑杆织机引纬机构的反求建模与运动学仿真

为了提高剑杆织机引纬机构的设计灵活性和运动性能,提出了一种新型偏心圆-非圆齿轮行星轮系引纬机构.根据引纬机构的工作要求,设定了理想的剑杆运动规律,并建立了由理想引纬运动特性反求机构参数的数学模型;基于MatLab编写了该引纬机构的反求设计与仿真软件,并对该引纬机构进行参数优化和运动模拟,得到了一组较优的机构参数;最后建...     

基于MATLAB空间四连杆引纬机构运动仿真

为了分析探讨剑杆织机空间四连杆引纬机构参数变化对其运动学特性的影响,通过代数解析的方法建立了该机构各部分数学模型,编制了MATLAB程序对其进行运动仿真,得出了运动特性曲线,同时定量分析了转速和曲柄长度变化对引纬机构运动规律的影响。分析结果表明,所得的运动特性曲线符合所需引纬要求,可以通过调节转速和曲柄长度优化运动规律曲线。     

曲柄凸轮压力机机构的仿真分析

文章通过对现有的压力机机构进行分析,设计了曲柄凸轮机构的压力机,并利用Solidworks软件对机构进行建模,通过该软件的Motion模块对机构进行运动分析,得到机构组成部分的运动数据,通过分析数据可以了解机构组成部分的运动特性,并为优化压力机机构设计提供重要参数。     

凸轮传动机构的参数化模拟实现

凸轮传动机构是常见运动机构之一,由于凸轮外廓决定机构的运动特性,故要调整其运动特性就需调整轮廓形状,致使设备调试中难以对凸轮机构进行调整。运用四连杆机构替换凸轮机构,并将凸轮机构的运动规律转换为连杆机构伺服电机运行参数,再经由软件进行运动参数设置,可实现不同凸轮运动的模拟及运动参数的灵活设置。     

四连杆运动的参数化模拟实现

四连杆机构是常见的运动机构,由于其运动特性与结构参数相关,故要调整其运动特性就需调整结构参数,因此给设备调试带来不便。本文运用伺服控制原理,采用在软件上设置结构参数,由伺服机构模拟相应结构参数的四连杆运动。可实现调试试验时灵活设置参数,而后选取最优状态的结构参数值作为四连杆机构的设计参数。     

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