草浆高浓黑液的流变性与粘流温度效应

利用Rheometrics RFSII流体粘弹仪测量了蔗渣浆黑液多聚物体系的剪切应力，表现粘度与剪切速率的关系，由实验得出了蔗渣浆高浓黑液在工程剪切速率范围（10^-1～10^3s^-1)内属剪切稀化流体，浓度和温度越高，黑液的剪切稀化现象越显著。此外，利用Brookfield粘度仪测定了黑液的剪切粘度与温度的关系，得出蔗渣浆黑液的粘度与温度的关系符合指数递规律。粘度越大，黑液粘度对温度的依赖性越强。     

黑液的粘度

概述了黑液粘度的研究成果，讨论了几种因素如深度，温度、剪切速率等对黑液粘度的影响，并讨论了黑液粘度的热稳定性以及黑液的降粘措施。     

高浓度木浆、草浆混合黑液的流变性能研究

利用AR550流变仪研究了高浓木浆与草浆混合黑液的流变特性与粘温效应（35～75℃）,发现浓度越高,粘度对温度的依赖性越大。与纯木浆或草浆黑液不同的是,在较宽的剪切速率范围内（10～10^4s^-1）,随着剪切速率的增加,混合黑液呈现了较明显的剪切稀化特性;因受到浓度增大的影响,超过一定温度后,反而有低剪切粘度的突变。在线性粘弹范围内进行频率扫描,发现黑液浓度越高,越呈现较强的弹性性质。     

用黑液预煮提高蔗渣化学浆的得率和粘度

对用黑液预煮蔗渣的两段硫酸盐法蒸煮进行了研究,结果表明,经黑液预煮后,第2段蒸煮蔗渣时脱木素选择性及速率提高,因此,可降低最高温度,减少蒸煮时间。所得的浆较 硫酸盐法蒸煮的浆得率高,粘度,太原市 锰钾值较低。在用黑液预煮蒸渣至115℃后（预煮时间40－45min),第2段蒸煮的最佳工艺条件为：用碱量13．5％（Na2O计）,硫化度25．9％,液比1：5,最高温度150℃升温时间45min,保温时间30min以此工艺条件蒸煮的浆与常规硫酸盐法蒸煮的浆相比,硬度相着差很小,而得率提高了9．65,粘度提高了138mL/g     

PP-COPET-ZnO三元共混物流变性的研究

采用CFT-500型毛细管流变仪测试了PP-COPET-ZnO三元共混物的流变性能.结果表明: 在230 ℃,250 ℃下,随γ增大,共混物的σ12 增大.PP-COPET-ZnO三元共混物的非牛顿指数n均小于1,随COPET含量的增大,温度的提高,共混物的非牛顿指数n增大.在测试的剪切速率范围内熔体表观粘度随剪切速率的增加而下降,为典型的假塑性流体.共混物的η0和Δη0随COPET含量的增加而减小.温度提高,共混物的表观粘度下降,下降幅度与剪切速率有关.     

蔗渣碱法制浆蒸煮黑液增浓过程中的相变化

利用DSC的热分析法探讨了蔗渣浆黑液在蒸发浓缩中的相转变过程。当蔗渣黑液中固形物含量接近40%时，黑液聚合物由水的连续相转变为聚合物（由有机物和无机物组成）的连续相。此时，黑液由凝固点（冰点）温度过渡到玻璃化转变点温度，相应地，黑液的物化性能如粘度等变化很大。     

海藻酸钠/羧甲基纤维素钠纺丝溶液的流变性能研究

采用毛细管流变仪测定海藻酸钠/羧甲基纤维素钠纺丝溶液的流变性能,结果表明:海藻酸钠/羧甲基纤维素钠纺丝溶液是"切力变稀"流体,随着剪切速率的增加,纺丝液的表观粘度ηa下降.纺丝液中CMC的含量和温度影响纺丝液的流变行为,纺丝液的表观粘度ηa和结构粘度指数△η随羧甲基纤维素钠含量的降低和纺丝液温度的升高而下降;纺丝液的非牛顿指数n随羧甲基纤维素钠含量的降低和纺丝液温度的升高而升高.因此,纺丝时应控制40℃左右的纺丝液中CMC的含量低于20%.     

蔗渣黑液流动性能的研究

通过对碱回收炉前蔗渣黑液的研究 ,发现黑液粘度与温度的关系满足方程 ηa=1189.2T-0 .9675。温度6 0℃时 ,在剪切力的作用下 ,黑液的流动呈现典型的非牛顿流体性质 ,并满足方程 :ηa=12 74.9e-0 .2 874D。黑液pH值增加 ,有利于黑液液化 ,但其粘度增加 ;相反 ,黑液 pH值下降 ,黑液软化点降低 ,而粘度下降。     

羧甲基淀粉糊料流变性能研究

研究了羧甲基淀粉糊料制备及其流变性能.分析了影响羧甲基淀粉流变性能的因素:糊料含固量、剪切速率、剪切应力、振荡频率、温度.结果表明:含固量增加,羧甲基淀粉粘度上升;剪切速率增加,表观粘度迅速降低;温度升高,羧甲基淀粉粘度下降等.通过小幅振荡剪切应力扫描、频率扫描试验得出,随着温度的升高,储能模量和耗散模量下降,损耗角增大,流变性能发生明显变化.     

蔗渣制浆黑液热性质的研究

蔗渣浆黑液在蒸发和碱炉中有其独特的热性质.对蔗渣浆黑液的加热过程表明在180～190℃前,黑液主要以蒸发水分为主,考虑到高温下黑流易于流动和翻腾搅拌的特点,蔗渣浆黑液高浓蒸发的温度建议设在180℃;升温至255℃,黑液的部分固形物会热解产生液体的油状物及气化苯酚和乙烯苯;255～590℃黑液继续裂解,产生了木素大分子的碎解产物和小分子有机物;加热到650℃时,固形物中的盐分分解.     

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