冷冻对纸张耐久性影响的研究

低温冷冻杀虫和低温冷冻干燥是备受推崇的纸质藏品保护技术,但是冷冻对纸张耐久性的影响研究尚不充分。为了避免对纸质藏品造成保护性伤害,本文考察了冷冻对不同含水量的酸性纸和中碱性纸耐久性的影响。研究发现,冷冻对纸张耐久性的影响与其含水量和纸张类型相关。冷冻对于干燥中碱性纸耐久性无影响,会降低潮湿和浸湿中碱性纸耐久性,对不同含水量酸性纸耐久性均存在劣化作用。因此,低温冷冻杀虫处理适用于干燥的中碱性纸质藏品,低温冷冻干燥需进一步改善工艺提高其安全性。     

化学检测手段在纸张断代中的应用

通过对不同年代(约1800年、1961年、1978年、1988年、2022年)纸张中造纸化学品的检测鉴别,结合纸张年代与造纸化学品的多方面依附因素分析,对纸张进行断代识别。实验结果表明:造纸化学品在判断纸张年代上有较大的依附性。通过高效液相色谱分析,1988年和2022年纸样都存在荧光增白剂,这与荧光增白剂在中国造纸行业的使用时间相符合。通过X射线衍射(XRD)技术对纸样的造纸填料进行分析,分别在1961年和2022年纸样中检测到碳酸钙,1988年纸样中检测到滑石粉的存在。通过化学检测法对纸张的胶料进行检测,通过实验得出在1800年、1961年、1978年纸样中存在松香胶料,1988年和2022年纸样存在淀粉,推测可能使用淀粉胶,但动物和大豆等蛋白胶均无显现。通过对纸张进行扫描电子显微镜(SEM)检测,发现SEM结果与实验所推测相吻合,古书籍纸样纤维明显,基本没有填料助剂,其余纸样均存在明显的填料颗粒,且1988年和2022年纸样的填料形态和均匀度更好。结果表明:纸张样品的化学检测和表征测试结果,可以用于纸张断代分析。     

氢氧化钠-尿素水溶液处理对麦草浆纸张强度性能的影响

利用氢氧化钠-尿素水溶液在低温条件下处理漂白麦草化学浆成纸,通过单因素试验探求碱浓度、浸渍时间、冷冻温度和冷冻时间等因素对纸张强度性能的影响,并利用红外光谱仪、X-射线衍射仪以及扫描电子显微镜表征处理前后纸张微观结构的变化。结果表明:在碱浓度6%、浸渍时间3s、冷冻时间12min以及洗涤时间10min的工艺条件下,处理后纸张的强度性能最好。处理前后纸张的红外光谱图和X-射线衍射图谱均没有明显变化,但纤维表面形态变化明显。     

保存环境对纸张性能的影响研究

纸张的保存寿命是文献保存寿命的重要方面,本文研究了单宣、桑皮纸、苦竹纸、字典纸和打字纸在氮气、空气和密封三种保存环境下,在105℃下热老化72h后纸张的白度、撕裂度和冷抽p H值的变化,同时进行被动采样研究了老化过程中环境中的气体。实验结果表明:通氮气的防老化效果最好,通空气的防老化效果次之,密封的防老化效果最差。不同种纸张的三种老化效果存在差别,耐久性最差的打字纸的效果区分最明显,而耐久性最好的构皮纸的效果区分最不明显。     

喷墨印刷中纸张特性对印品阶调层次影响研究

本文探讨了喷墨印刷中纸张特性对印品阶调层次的影响,并对不同纸张特性的影响效果进行评价。实验采用Epson stylus Pro 7800和Epson Stylus c88+两种喷墨打印机对HP、Epson等品牌的五种喷墨打印纸进行研究。研究发现承印材料的性质与印品的阶调变化明显相关。孔隙率及粗糙度高的纸张,其印品图像的亮调区域由于网点细小而无法在纸张上完整再现,网点密度为0,图像的亮调层次丢失,如EPSON C88+在2#、3#纸样上输出的1%-C和2%-C所示,其密度为0;纸张越粗糙,其吸墨量越高于表面光滑的纸张,由此导致图像的暗调部分合并过早,暗调层次丢失,如4#纸样印样所示。同时,纸张特性也是影响相对反差K值的主要因素之一。纸张的光泽度、粗糙度、孔隙率等均对印品的相对反差有一定的影响。     

基于碱脲溶剂体系胶化作用的湿强纸的制备

在低温及中高浓度条件下,利用氢氧化钠 硫脲水溶液浸渍处理由漂白硫酸盐慈竹浆抄造的纸张,经冷冻及洗涤后制备湿强纸,通过单因素实验探究碱浓、浸渍时间、冷冻温度、冷冻时间和洗涤时间等因素对纸张强度性能的影响,并利用傅里叶变换红外光谱仪、X射线衍射仪、热重分析仪、核磁共振波谱仪和扫描电子显微镜表征处理前后纸张性能的变化情况。结果表明,在碱浓7%、浸渍时间3 s、冷冻温度-7℃、冷冻时间15 min、洗涤时间15 min的处理条件下,制得的湿强纸强度性能最好。与处理前原纸相比,在该条件下处理后纸张的干抗张指数提高了66%,干耐破指数提高了183%,湿抗张指数提高了321%,湿耐破指数提高了980%;同时处理后纸张中单根纤维的含量显著降低,且处理前后纸张纤维的官能团结构、无定形区和结晶区结构、热力学性能以及碳骨架结构均没有明显变化。     

基于阳离子聚合物和纤维素纳米纤丝的二元纸张增强体系

将聚酰胺多胺环氧氯丙烷树脂(PAE)、阳离子淀粉(CS)分别与纤维素纳米纤丝(CNF)组成二元增强体系,考察其对一种以针/阔叶木混合浆(配比为30/70)为原料抄造的低定量(30 g/m2)纸页的增强效果。结果表明:PAE/CNF二元体系对纸张的增湿强效果明显,PAE用量为0. 5%(助剂绝干量对纸浆绝干量的质量百分数)、CNF用量为0. 3%时,纸张湿抗张强度是未处理空白纸样的6. 2倍,是PAE单独处理纸样(PAE用量0. 5%)的1. 76倍;CS/CNF二元体系则对纸张的增干强效果较为明显,CS用量为2. 0%、CNF用量为0. 3%时,纸张干抗张强度是未处理的空白纸样的1. 65倍,是CS单独处理纸样(CS用量2. 0%)的1. 26倍。     

葡萄霜霉病菌长期保存方法的研究

为了解决葡萄霜霉病菌的活体保存问题,本文开展了多种保存方法的研究。采用5%二甲基亚砜低温冷冻保存、液氮冷冻保存和琼脂粉包裹冷冻保存等三种方式,调查不同低温条件和不同保存时间对孢子囊致病性的影响。结果表明:用不同保护剂处理后葡萄霜霉病菌单斑病叶保存于-80℃中30 d,5%二甲基亚砜处理的孢子囊经回接后发病面积百分率为69.32%,其致病性明显高于液氮冷冻处理和琼脂粉包裹处理;低温保存条件下,-80℃中保存的孢子囊回接后致病性明显高于-20℃的处理;三种保存方式均表现随着保存时间的延长,致病性逐渐降低。     

不同纸张喷墨打样颜色饱和度的研究

本实验采用EPSON7800型喷墨打印机对喷墨打样中纸张性质对印品颜色饱和度的影响进行了研究。选取5种纸样,测试纸张的性能,喷墨打样后,分析纸张性能对色域、色差、饱和度差的影响,并就白度、光泽度、粗糙度、孔隙率等性能对颜色饱和度的影响权重进行了讨论。研究发现,纸张性能对饱和度的影响权重依次为白度、光泽度、孔隙率、粗糙度,其中白度对颜色饱和度的影响最大,光泽度次之,粗糙度和孔隙率的影响相对较小。     

纳米纤维素/纳米氧化锌对纸质文献脱酸与增强效果的研究

采用丝网印刷工艺将纳米纤维素(CNFs)/纳米氧化锌(ZnO)保护液涂布于纸张表面对纸张进行脱酸和增强处理。研究了ZnO用量、CNFs用量和涂布量对纸样的脱酸效果和增强效果的影响,同时研究了ZnO用量对纸样疏水效果的影响。结果表明,经过CNFs/ZnO保护液处理后,当ZnO用量为2.5 wt%时,纸样内部pH值可由未处理时的4.99增加至7.30,表面接触角由90.1°增加至115.5°;当CNFs用量为0.55 wt%,纸样的抗张指数最高可增加296.53%;另外纸样的pH值和物理强度随着涂布量的增多而有所提高,涂布量达到最大值4.6 g/m^2时,纸样的物理强度均达到最大值。此外,ZnO用量对纸样白度影响较小,色差最大仅为4.01。说明CNFs/ZnO保护液不仅能脱酸,并且能显著提高纸质文献的物理强度,同时具有疏水效果,可进一步对纸质文献进行保护。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.