测试衬板对透明度检测值的影响

透明度与不透明度都是反映纸张透光程度的指标，但其测试方法有所不同。国家标准GB1543－88规定不透明度的测试，是以纸背衬（厚度需达到反射因数不再随厚度增加而提高）绿光测R，再以黑筒为背村绿光测单层纸民，然后，按不透明度一民／R＿X100％的公式计算不透明度值。但当纸背衬的厚度达不到上述要求时，即纸的透明度较高时，不透明度的测试较困难。因此，国家标准GB2679．1－81规定透明度测试，是以反射率为84土1％的标准白板作为背村测民，再以黑简为背衬测单层纸民，然后，按透明度一（R，一比）／R，X100％的公式计算透明度值。由…     

纸张不透明度的测试及注意的问题

纸张不透明度的测试及注意的问题刘德文（四川省造纸工业研究所）纸张的不透明度是指带黑背衬的单层纸的反射团数Ｒ。与同一试样的内反射因数Ｒ∞的百分比。这个指标的高低，将直接影响到纸张在印刷过程中的透印程度。不透明度越高，透印发生的机会就愈少，反之就愈多。因...     

纸张填加沉淀碳酸钙的试验

沉淀碳酸钙加填于纸浆中能较好地提高成纸的不透明度，在偏三角形（Ｓ－ＰＣＣ），棱柱形（Ｐ－ＰＣＣ）和斜方形（Ｒ－ＰＣＣ）三种不同类型的沉淀碳酸钙中，斜方形沉淀碳酸钙（Ｒ－ＰＣＣ）作为纸张填料具有更高不透明度，用量为２０％的手抄纸片，不表明度高达９２．５％。     

纸张透明度的某些理论计算式

本文讨论了1．纸张背衬不同衬底的透明度的换算公式，使在不同衬底下测得的透明度可以换算成标准的透明度。2．不同定量的纸张的透明度的换算方法，使纸张的透明度可以在同一定量下比较。3．纸张亮度对透明度的影响。     

纸张填加沉淀碳酸钙的试验

沉淀碳酸钙加填于纸浆中能较好地提高成纸的不透明度，在偏三角形（S－PCC）、棱柱形（P－PCC）和斜方形（R－PCC）三种不同类型的沉淀碳酸钙中，斜方形沉淀碳酸钙（R－PCC）作为纸张填料具有更高不透明度，用量为20％的手抄纸片，不透明度高达92．5％．     

手性还原剂用于苯乙酮的不对称还原研究

（１Ｓ,２Ｒ）－１－二丁氨基－１,２－二氢－２－茚醇（ＲＯＨ）与氢化铝锂形成的手性试剂首次用于苯乙酮的不对称还原研究．根据手性试剂制备后的使用方法（方法Ａ∶立即使用;方法Ｂ∶回流１０ ｍ ｉｎ 后使用）,苯乙酮还原后可分别给出对映体过量值达６０％ ～７６％ 的不同主产物Ｒ－（＋ ）－１－苯基乙醇和Ｓ－（－）－１－苯基乙醇．研究了反应物物质的量之比（ＬｉＡｌＨ４ ｖＲＯＨｖＰｈＣＯＭｅ）对立体选择性的影响,当反应物物质的量之比为１．０ｖ１．５０ｖ１．５０时有较高的对映体过量值和转化率．这种手性还原剂为不对称合成光学活性醇提供了一种选择．     

国家轻工业局批准QB2446-1999《自然食用盐》等四项行业标准修改单

［本刊讯］ＱＢ２４４６－１９９９《自然食用盐》第１号修改单、ＱＢ２２３８－１９９６《强化营养盐》第１号修改单、ＱＢ２３５３－１９９８《膨化食品》第１号修改单、ＱＢ１００２－１９９７《胶粘皮鞋》第１号修改单，业经国家轻工业局国轻行［２０００］３８０号文批准。更改内容已于 ２０００年 １１月 １日起实施。 行业标准修改通知单ＱＢ２２３８－１９９６《强化营养盐》第１号修改单 （１）封面 ＱＢ／Ｔ２２３８－１９９６改为ＱＢ２２３８－１９９６ （２）第３页表４中水不溶物改为酸不溶物。 （３）第５页 ４．８．１．３…     

减少纱线漂染污水的工艺探讨

１　采用新型染料染色上海万得化工有限公司生产的ＭｅｇａｆｉｘＢ型活性染料和上海染料化工八厂生产的ＥＦ型活性染料，不含有违禁的芳香胺致癌物质，属环保型染料。同时它们都具有新型的双活性基团，上染率和色牢度都较高，染料固着率可达７０％～８０％，因而可减少污水的浓度。工艺示例比较：（１）原　　料，２８特纯棉绞纱；染色数量：１００ｋｇ；颜色：深红；ａ、普通活性染料处方：１４０％Ｘ－ＧＮ橙；８０００ｇ；１００％Ｘ－３Ｂ红：５５００ｇ；１２０％Ｘ－２Ｒ紫：３５００ｇ；食盐：６０ｇ／ｌ；纯碱：１０ｇ／ｌ；浴比：…     

蜂蜜的流变热力学特性研究

利用过渡状态理论研究了流体的微观结构与粘度的关系，并在利用统计力学和量子力学结果的基础上，提出了从理论上计算流动化能和流动活化熵的可能性，导出公式：η＝Ｎｈ／ＲＴｅｘｐ（－Δｓ≠Ｒ＋Ｅａ／ＲＴ）。同时，将其运用于蜂蜜之中，计算了蜂蜜的流动活化能和流动活化熵，将理论值五测定值进行了比较分析。     

广义Brownian Sheet的鞅刻画

在文献［１］的基础上给出了广义ＢｒｏｗｎｉａｎＳｈｅｅｔ鞅刻画：两参数连续适应过程（Ｂ２）ｚ∈Ｒ２＋为广义ＢｒｏｗｎｉａｎＳｈｅｅｔ的充要条件是（Ｂ２）ｚ∈Ｒ２＋为Ｆｏｕｑｕｅ意义下的两参数局部鞅，且存在Ｒ２＋上的Ｌ—Ｓ测度ｄ，（ｄ《λ，λ为Ｒ２＋上的Ｌｅｂｅｓｇｕｅ测度）使得（Ｂ２ｚ－ｄ（Ｚ）ｚ∈Ｒ２＋为Ｆｏｕｑｕｅ意义下的两参数局部鞅，其中以ｄ（ｚ）＝ｄ（（０，ｚ］）。     

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