弹性连杆对平行打纬机构前死心位置的影响

随着织机转速提高，共轭凸轮与四连杆组合的平行式打纬机构中的连杆构件会在惯性载荷的作用下变形加大，从而导致钢筘前死心位置与理想位置产生偏差，影响打纬精度。针对该问题采用虚拟仿真与实验结合的方法对机构进行研究，建立了平行打纬机构柔性连杆下的动力学模型，并运用ADAMS软件进行仿真，探究不同凸轮转速和连杆不同材料对钢筘前死心位置的影响，同时搭建实验平台对仿真结论进行验证。结果表明：凸轮转速对钢筘前死心位置的影响是非线性的，凸轮转速在180 r/min以内钢筘的前死心位置稳定且偏差值较小。弹性连杆构件选用比刚度更大的材料有助于减小钢筘前死心位置偏差。研究结果可为高速共轭凸轮平行打纬机构的设计和优化提供参考。     

剑杆织机筘座脚,摇轴的调整方法

一些挠性剑杆织机如石川725、丰田LT102、台湾亨得、香港捷豹等。采用共轭凸轮打纬。打纬机构采用共轭凸轮、筘座用空心梯形铝合金制成。筘座与传剑机构相分离,传剑机构安装在织机的另一固定位置上。筘座用共轭凸轮传动,引纬时筘座在后方静止,这种结构形式减轻了传剑部分的设计难度,增加投纬角     

无梭织机常用打纬机构打纬力对比分析

分析了连杆打纬机构和共轭凸轮打纬机构的特点,计算了两种机构的打纬力,指出两种机构各有特点,不存在谁比谁优的问题.共轭凸轮打纬机构在引纬时可使筘座保持不动,更适合剑杆织机的要求,而连杆打纬机构无此特点,更适合喷气织机采用.     

非对称运动打纬凸轮的设计

无梭织机(包括片梭织机、挠性或刚性剑杆织机、喷气织机及喷水织机)普遍采用共轭凸轮打纬机构,其主要原因是: 1.因多数无梭织机均采用分离筘座,为了配合引纬运动的要求,筘座必须有停顿时间。一般筘座的运动时间约占工作周期的1/3左右,而筘座的停顿时间约占工作周期的2/3左右。采用共轭凸轮机构可以实现以上的运动要求。     

剑杆织机打纬机构动力学分析及仿真

打纬机构是剑杆织机中利用往复摆动的筘座将纬纱打向织口的机构,它与织机的工作效率和机架墙板的寿命密切相关。为研究打纬机构对织机墙板振动的影响,建立了四连杆打纬机构的理论模型,对打纬机构进行了运动学和动力学分析,求出轴承支座的约束反力,并利用ADAMS对机构虚拟样机进行了动力学仿真,仿真结果验证了理论分析的正确性,为后续研究织机墙板振动特性和优化提供了参考依据。     

共轭凸轮打纬机构分析与优化

文章对共轭凸轮打纬机构进行了简要介绍,建立了某剑杆织机共轭凸轮打纬机构的虚拟样机,分别对主副凸轮及单侧共轭凸轮进行了运动学仿真及研究,并同时针对实际工况中的问题,对该共轭凸轮进行了优化设计。本文的方法对旧织机改造与新型织机开发具有一定的参考意义。     

虚拟样机技术在织机打纬机构分析中的应用

共轭凸轮打纬机构是控制织机的关键部件,是决定织机运动速度和平稳的关键因素之一。利用ADAMS软件建立了共轭凸轮打纬机构的虚拟样机,分别对共轭凸轮打纬机构进行了运动学、动力学仿真分析,该分析方法有助于稳定和提高打纬质量。     

基于Hermite多项式的打纬运动学方程及其应用

为使打纬机构运行平稳,性能达到理想的织造要求,采用由理想运动学方程反求机构参数的方法,用4段光滑拼接的三次Hermite多项式建立剑杆织机打纬机构加速度曲线方程,再由加速度曲线方程及其边界条件推导出剑杆织机打纬机构速度、位移和跃度曲线方程,并对运动学方程中参数的计算进行了说明。将所建立的运动学方程用在共轭凸轮打纬机构的参数反求,得到了机构参数和曲率变化均匀的共轭凸轮廓线。研究结果表明,建立的运动学方程不仅能够满足共轭凸轮打纬机构参数反求的要求,而且所求共轭凸轮具有较好的力学特性。     

制织上等衣料的理想的剑杆织机

1.G6200型剑杆织机的技术特点 1.1机身 ——对机器进行最优化设计以减小振动减轻了机身重量机身不与地坪固定 ——结构紧凑,机身较低,护板功能齐全操作方便舒适清洁保养方便容易 ——筘座强度高,质量分布均衡可以制织高密度厚重织物 ——最佳的打纬行程具有最佳的纬纱织缩率 ——双侧均装有共轭凸轮     

碳纤维织物打纬机构国内外发展综述

为了提高织物的产量和质量,了解打纬机构的发展,从织机打纬机构的类型和增加打纬力等方面,介绍连杆式和共轭凸轮式摆动打纬机构及平行打纬机构的优缺点;简述目前各类打纬机构运动学及动力学方面的研究进展。指出:连杆式打纬机构具备结构简单、制造容易、成本低、维护方便等优势,但筘座运动没有静止时间,不利于引纬,在传统低速织机上应用较为普遍;共轭凸轮式打纬机构具备更大的引纬角,筘在后心位置附近停留时间更长,为引纬提供充足的时间,不仅能实现平行打纬,且该机构响应快、输出打纬力充足,在宽幅、高速织机上应用较广,不仅能用于普通单层碳纤维织物织造,而且能满足碳纤维多层及中空织物的生产要求,适用性强。     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press