关于铜版纸性能对印刷品质量影响的实验与研究

纸张的性能可以分为一般性能,主要包括定量、厚度、紧度等;机械性能,主要包括抗张强度、耐折度、撕裂度等;光学性能,主要包括白度、光泽度、不透明度等;表面性能,主要包括平滑度、粗糙度、表面摩擦系数等;印刷性能,主要包括表面强度、油墨吸收性、平滑度等。本文主要从平滑度、光泽度、白度、吸墨性等这几个要素入手,通过对这几项纸张性能进行实验和分析得出纸张性能与印刷品质量之间的关系。     

纸张平滑度与印刷的关系及其测量仪器

纸张性能的好坏不仅标志着造纸工业的发展水平,而且还影响印品质量。纸张作为印刷的主要承印材料,对印品质量的优劣起到关键作用。纸张的参数主要有定量、尺寸、平滑度、光泽度、白度、吸墨性等。在纸张的众多性能指标中,平滑度是对纸张进行评价的一个重要参数,平滑度指标是否达到要求是衡量纸张质量的标准之一。     

纸张pH值对印刷过程的影响

纸张是极其重要的承印材料,正确深入地认识纸张性能是保证印品质量的前提。一般来说,纸张性能包括物理性能（如定量、厚度,平滑度等）、机械性能（如各种力学性能等）、光学性能（白度、光泽度等）及化学性能等。纸张pH值属于化学性能,通常指的是浸泡过的纸或纸板的水溶液的pH值,其对印刷复制过程及印品的质量有着重大影响。     

纸张平滑度与印刷品质

纸张印刷适性包括纸张的平滑度,吸墨性、光泽度、施胶度、白度、机械特性及尺寸稳定性等.其中,纸张的平滑度是决定印刷质量的首要条件.     

纸张的表面性能对印刷质量的影响

纸张的表面性能主要包含有平整性、平滑度、光泽度、表面强度、白度和匀度等概念。其中平滑度、光泽度、表面强度和白度都可以作定量表达,平整性和匀度目前只能做定性表述。本文就平整性、平滑度、光泽度和表面强度与印刷过程之间的关系及其对印刷品质量的影响,作一扼要地讨论。 纸张的平整性,是指单张纸水平放置在光滑的平板上,其表面呈现平面还是凹凸鼓包或翘曲不平以     

纸张物性对印刷颜色效果的影响

<正>纸张作为印刷的基本要素之一,是目前印刷工艺中占比最大的承印物。纸张物性对印刷颜色效果的影响非常大。影响方式有两种:直接影响和间接影响。直接影响因素主要是纸张的光学物性,包括纸张的颜色、白度、透明度、光泽度等;间接影响因素主要是纸张的印刷适性,包括纸张的平滑度、     

空心塑料颜料对涂布纸性能的影响

本文研究了空心塑料颜料对涂布纸性能的影响，包括：光泽度、白度、不透明度、松厚度、平滑度以及温度和压力对其性能的影响。     

高岭土颜料泥浆及其所形成之涂料的流变学原理

配制涂料时流变学如同涂布纸的光泽度、白度、不透明度、平滑度、印刷适性等同样重要.涂料的流动行为不仅影响到运转性能、能耗,而且也可能影响到成纸的质量,如孔隙度、白度、不透明度、光泽度及印刷适性等.流动特性在整个涂布系统中起着重要作用,包括涂料制备、输送、施涂、胶膜形成和固化.     

丁苯胶乳用量对涂料及涂布纸性能的影响

探讨了丁苯胶乳用量对涂料及涂布纸性能的影响。结果表明:当胶乳用量增加时,涂料的低剪切黏度上升,高剪切黏度和保水值降低;涂布纸粗糙度、光泽度、油墨吸收性和花斑降低;涂布纸平滑度、印刷光泽度、干拉毛值、CIE白度和ISO白度上升。     

造纸填料粒子大小、形状、结构及其对纸张性能的影响

加大填料数量，可导致纸张大部分物理性能方面的减弱，如撕裂度、抗张强度、刚度等等；而白度和不透明度将逐渐增加，平滑度得以改善；松厚度和透气性能值也可能提高或降低。在给定的加入量上，颗粒较细小的填料对强度和光学性能比颗粒较粗大的填料影响更大，而较扁平颗粒...     

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.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status