一种生产低定量瓦楞原纸新方法

<正>本刊讯纸箱的发展趋势是向高强度、高质量、低成本、小瓦楞方向发展,这就要求瓦楞原纸要向低定量、高强度发展。如瓦楞原纸的定量已由150g·m-2到130g·m-2,再到近年的120g·m-2、110g·m-2。王德贤等人研究了一种生产低定量瓦楞     

瓦楞原纸定量测量不确定度的评定

按照测量不确定度评定的基本方法和程序对瓦楞原纸定量测量结果的不确定度进行了评定,不确定度来源主要是取样,其次为质量M的重复性测量和天平校准;瓦楞原纸定量测量结果的扩展不确定度是1g／m^2,包含因子为2;为提高定量测量准确度,应定期对定量标准试样取样器进行校准。     

通过表面施胶提高瓦楞原纸的环压强度

对以废纸生产的瓦楞原纸进行表面施胶处理,可以显著提高瓦楞原纸的环压强度.以100%国内OCC为原料,若双面总施胶量为9.0 g/m2,可使112 g/m2瓦楞原纸的环压指数达到8.0 N·m/g以上.     

对苇浆生产彩色皱纹原纸性能指标的认识

彩色皱纹纸系以一定质量性能的原纸为基础，通过表面涂布染料并加工起皱，使之具有色彩鲜艳美观、皱纹匀整细腻、纸质柔软、强韧、富有弹性的特点，以供制作结彩装饰用的一种加工纸张。根据皱纹纸使用的特点和要求，特别应该注意原纸的质量。原纸必须薄，具有一定的吸收性能，柔软性高而且必须有良好的纸层组织。原纸要求打浆程度较低，不施胶，有一定的物理强度，表面匀整，无纸病，纤维组织松紧适宜（紧度一般为0．4g／cm‘左右）。下面仅就苇浆在圆网纸机上抄制薄型皱纹原纸几个性能指标谈一些看法。1定量定全系皱纹原纸一项最重要的质量…     

影响扬声器纸质振膜动态力学性能的因素

研究了不同定量、不同浆料打浆度对扬声器纸质振膜材料动态弹性模量和损耗因子的影响,并对复合纸质振膜的动态力学性能进行了研究.结果表明,随着纸张定量的增加,浆料打浆度的提高,纸张的紧度和动态弹性模量升高,损耗因子下降.纸质振膜的复合结构影响其动态力学性能,与原纸相比,干法复合导致复合纸紧度和损耗因子均升高,湿法复合使复合纸紧度降低而损耗因子升高,无论干法还是湿法复合后,复合纸的动态弹性模量变化均不明显.     

浅析网前箱结构的技术改造

介绍如何改造网前箱结构,以达到生产240g／m^2纸杯原纸所需要的产能和上网浆料流型，并满足纸页整幅定量差的需要。     

提高白色水松原纸不透明度的研究

该文讨论了提高水松原纸不透明度的意义,研究了填料和浆料的不同取代比例对定量为32g/m2的白色水松原纸的抗张强度、施胶度及不透明度的影响.结果表明,增加针叶木浆的配比能提高白色水松原纸的不透明度,选择适合的填料及其配比也能提高其不透明度.     

高强瓦楞原纸干燥曲线在线测量与分析

通过在线测量某高强瓦楞原纸厂干燥部不同烘缸位置湿纸幅的定量,获得纸幅干燥曲线,采用最小二乘法拟合,获得最能解释纸幅干燥过程的干燥曲线模型。利用该模型对测试对象干燥部进行分析,得到干燥曲线和各烘缸出力情况,结合纸幅温度测量数据,可知测试对象纸幅干燥过程为:纸幅加热阶段(1#~2#缸)、恒速干燥阶段(3#~22#缸)、减速干燥阶段(23#~48#缸)。该原纸临界含水率为0.29 g水/g(d.s.)。烘缸出力最大在8#缸位置,为29.17 kg水/(m2·h)。     

Stora Enso计划在俄罗斯进行重要投资

世界上最大的箱纸板机——德国woerth papierfabrik Palm^#6机正在增产，该纸机现在的生产能力是507／t／a。^#6机2002年由美卓提供，用来生产定量为90～140g／m^2的高强瓦楞原纸、定量为80～130g／m^2的瓦楞原纸及定量为70～120g／m^2的纸盒纸板，自其开机以来生产的各个等级产品的质量都相当好。     

淀粉-无机盐体系表面施胶可提高瓦楞原纸的强度性能

正青岛科技大学化工学院陈夫山等人用硝酸镁、氯化镁、硫酸镁取代部分玉米淀粉对瓦楞原纸进行表面施胶,探讨无机盐的添加对瓦楞原纸物理强度及其他性能的影响。结果表明,当淀粉与无机盐的用量比(质量比)为8:2、施胶量为6g·m-2时,相对于施胶前纸样,硝酸镁、氯化镁、硫酸     

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