慈竹密度和微纤丝角变异规律研究

以四川慈竹为材料,对其密度和微纤丝角在竹杆纵向和不同竹龄间的变异规律进行了研究。结果表明:慈竹气干密度从基部(1.5m)、中部(4.5m)到稍部(7.5m)逐渐增大,并且三个部位密度值间存在显著差异,同时慈竹密度随竹龄增大而逐渐增加,但不同竹龄气干密度值间差异较小;慈竹微纤丝角随竹高增大而减小,并且绝对值差异较小,基部、中部和稍部处竹材的微纤丝角间差异不显著;2年生到5年生间,竹材微纤丝角随竹龄的增大有增大趋势,方差分析表明,2年生与4、5年生慈竹微纤丝角之间均存在显著差异,4、5年生慈竹微纤丝角之间几乎没有差异。以上结果将为今后慈竹的竹林培育和工业利用提供理论依据。     

声-超声参数与木材解剖特征的关系研究

为探索利用声-超声(AU)技术预测落叶松木材解剖性质的可行性,测量了落叶松无疵小试样的波速(V)、峰值电压(A)、均方根电压(RMS)、上升时间(RT)、频率形心(FC)等五个声-超声参数和年轮宽度(RW)、晚材率(LR)、微纤丝角(MFA)、管胞长度(TL)和管胞宽度(TW)等5个解剖特征。分别利用一元线性回归分析方法和多元线性回归分析方法研究了声-超声参数与解剖特征之间的相关性。结果表明:1)不同解剖特征和单个声-超声参数之间的相关性存在差异。其中,管胞长度与波速呈显著正相关,其相关性决定系数较高(R~2=0.31),与其它4个声-超声参数的相关性较低(R~2≤0.16);微纤丝角与波速呈显著负相关,其R~2=0.46,与其它4个声-超声参数的相关性较低(R~2≤0.14);年轮宽度、晚材率、管胞宽度与5个声-超声参数相关性都较差(R~2≤0.11)。2)利用多元回归分析方法建立的微纤丝角线性预测模型的效果高于仅以波速为自变量建立的微纤丝角线性预测模型的效果,决定系数从0.46提高到0.63。     

玉米茎秆纳米纤丝纤维可改善废纸浆成纸的性能指标

玉米茎秆作为农业生产的废弃物价格稳定且可回收,用于制备纤维素纳米纤丝(C N F)的原料,研究发现CNF的添加可改善废纸浆成纸的性能。本实验以桉树纳米硫酸盐浆纤维素纳米纤丝(E-CNF)作为参照对比,研究同时发现向废纸浆中加入0.5%玉米茎秆纤维素纳米纤丝(C-CNF),会使成纸后纸张的抗张指数增加20%。当废纸浆中E-CNF的加入量为1.5%时,纸张的抗张指数增加20%;且随着E-C N F加入量的增加,纸张的抗张强度会得到进一步改善。本文主要研究C-C N F加入废纸浆后成纸,纸张的抗张强度得到改善的情况;纸张抗张强度的改善与废纸浆中各原料的配比无关。也就是说纸浆中无论废纸浆的配比怎么样都不会改善纸张的抗张强度。研究中发现C-CNF可以显著改善以旧瓦楞纸为主要原浆的抗张强度,仅轻度改善废纸的抗张强度。     

切短与压溃对制备柔性纳米纤维素纤维作用

天然纤维素超分子结构中存在高度规整的结晶区,以及微纤丝间超强的氢键强结合力使纤维素难以溶于大多数的普通溶剂,常规的化学或物理方法难以将纤维很好解离成微纤丝。本文依据木质纤维分子结构与形态特征,分析切断与切短、压溃、搓揉与剪切等方法对纤维微纤丝解离的作用。结果表明,纤维切短有助于纤维的压溃及纵向开裂,加速水分子向纤维内部渗透,削弱纤维微纤丝层间的结合力,促进纤维的润涨及水化;充分润涨与水化的纤维经机械搓揉及高剪切力作用,能实现纤维微纤丝的解离,得到尺寸均一的柔性纳米纤维。     

针叶材管胞纵向零距抗拉强度的研究

研究了杉木、马尾松木材管胞零距纵向抗拉强度.结果表明,杉木早材管胞纵向抗拉强度介于310MPa～733MPa,平均499MPa;马尾松早材管胞纵向抗拉强度介于300MPa～590MPa,平均461MPa.两个树种的早材管胞纵向抗拉强度在树高方向(1.3m～7.2m)差异不显著,没有明显的变化规律;含水率对早材管胞纵向抗拉强度的影响不显著,但总体趋势是气干态的强度高于饱水态.     

纤维素微纤丝的制备及应用

近来很多研究表明纤维素微纤丝具有很好的强度及韧性，无论是加入到一些复合材料中，还是在纸张中添加，都有很好的增强效果。本文首先讲述了纤维素微纤丝的制备及性质，然后讲述了纤维素微纤丝在复合材料及造纸中的应用，尤其是作为纸张增强剂的应用；最后对微纤丝的发展应用作出展望。     

MFC组分及形态的分析

均质化是将纤维素纤维解离的一种方法。该过程产生的物质一般称作微纤化纤维素（MFC）。微纤化纤维素不均一,含有纤维、纤维碎片、纤丝化细小组分及纳米纤丝。这意味着MFC与纳米纤丝、微纤丝或其他具有纳米尺寸的纤维素的含义不一定相同。采用适当方式制备的MFC主要组分是具有纳米尺寸的纤维,即纳米纤丝。     

纳米微纤丝纤维素及其在造纸中的应用研究现状

本文结合纳米材料定义,简述纳米微纤丝纤维素与传统意义纳米纤维素的共性与区别,在此基础上介绍此类纳米纤维素的制备方法及现阶段存在的主要问题。同时介绍了纳米微纤丝纤维素在造纸中潜在的应用方式,分析其对造纸规模化生产及纸张性能的影响并浅谈其发展面临的机遇与挑战。     

玉米茎秆纳米纤丝纤维可改善废纸浆成纸性能

<正>2016-10-09苗成报道(摘要):玉米茎秆作为农业生产的废料因其价格稳定且可回收,可用作制备纤维素纳米纤丝(CNF)的原料。研究发现CNF的添加可改善废纸浆的成纸性能。实验以桉树纳米硫酸盐浆纤维素纳米纤丝(E-CNF)为参照系,发现在废纸浆中加入0.5%的玉米茎秆纤维素纳米纤丝(C-CNF),可提高纸张抗张指数20%。随着E-CNF加入量的增加,纸张的抗张强度还可进一步改善。     

微纤丝与PAE协同作为纸张增强剂

用纤维素微纤丝和聚合电解质PAE配合使用可以提高纸张干强和湿强。通过用石英微量天平（QCM-D）和原子力显微镜（AFM）研究了微纤丝和PAE在纤维素模型表面的吸附情况。比较了微纤丝和PAE在纤维中的添加方式对纸张的纤维层结构和微纤丝形成的微聚集体的不同。结果表明：PAE首先被吸附在纤维素模型表面形成均匀层。然后微纤丝黏性层才被吸附：如果PAE和微纤丝是以阳离子混合体被吸附的。则形成的是不规则的刚性层：在抄造纸样时，当采用先加PAE后加微纤丝的双层（bi-layer）系统添加方式时，即使添加少量的PAE也能使纸样的干强和湿强明显增加；当采用PAE和微纤丝混合形成混合体然后添加的方式时，纸张强度的提高不是很明显。同时，通过对纸样体积和表面含氮量的分析表明，添加方式不会影响PAE的总吸附量，但是它对纸样中组成的分布有很大的影响，而组成的分布对纸张干强和湿强的形成有很重要的影响。     

Review of techniques to manufacture micro-hydrogel particles for the food industry and their applications

Microgels are ‘soft’ microscopic cross-linked polymeric particles that are being increasingly exploited in a variety of industries for rheology control, encapsulation and targeted delivery. They are valued because of the ability to tune their functionality to address specific applications in oil recovery, coatings, drug delivery, cosmetics, personal care and foods. Food microgels are typically biopolymer hydrogels in the form of microspheres, nanospheres (also called nanogels), spheroids and fibres. The utilisation of engineered microgels in foods has so far been limited, despite their great potential to address several needs in the food industry, including: satiety control, encapsulation of phytonutrients and prebiotics, texture control for healthier food formulations (e.g. reduced fat products), and targeting delivery to specific areas in the digestive tract. We review the scientific and patent literature on the utilisation and manufacturing methods for producing microgels with an emphasis on micro-hydrogels for food applications.     

12—A CRITIQUE OF SOME HYPOTHESES RELATING TO THE HETEROGENEITY OF THE HIGH-SULPHUR PROTEINS OF WOOL

Joubert and Burns prepared a large number of fractions from the high-sulphur proteins of wool and estimated their molecular weights and amino-acid compositions. Their data have been re-examined in order to look for statistically significant interrelations between amino acids and between the proportion of various amino acids and molecular weight. Statistical analysis of the data is also used to examine the credibility of some hypotheses concerning the mechanism of keratin biosynthesis and to provide further evidence for the existence of families of proteins within the high-sulphur fractions of wool.     

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 Latest Data about Development of Chinese Printing Industry in 2013

In the 2014 China（Shanghai）International Printing Week,Director Wang Yanbin released the latest data about development of Chinese printing industry in 2013.According to statistics,in 2013,the total output value of Chinese printing industry exceeded 1trillion Yuan for the first time,reaching 1.03985 trillion Yuan.There were 105,000 printing enterprises in China,employees were 3.415 million.The total asset was 1.06247 trillion Yuan;     

The State Council Issued "Directory of Government Approved Investment Projects(2013 Edition)"

正On December 2nd,2013,the State Council issued the notification of"Directory of Government Approved Investment Projects(2013 Edition)"(hereafter referred to as"notification").It is pointed out in the"notification"that in order to further deepen reforms in investment systems and administrative examination and approval systems,simplify administrative procedures and delegate powers to lower levels,earnestly     

China textile machinery: taking off in progress

正Among the 1600 exhibitors who take apart in the ITMA ASIA+CITME2014 2/3 are Chinese manufactures.If the numerous figures failed to attract your attention,the increase of quality should draw your focus.To adopt the demand of developing textile machine market,domestic textile machinery enterprises now follow the slogan of"technology drives development"to enhance product competitiveness.Our domestic sellers will showcase product ranging from spinning,weaving,dyeing and printing,     

Top Ten News of China's Paper Industry 2013

On December 24th, 2013, the meeting on the selection of top 10 news of China＇s paper industry 2013 sponsored by 〈China Paper Newsletters〉 was held in Beijing. The yearly selection of the top l0 news, which began in 2000, has become a brand activity widely recognized in the industry thanks to the support from the authorities at all levels and public participation.     

National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the "13~(th) Five-Year Plan"

In Apri Commi major p Plan＂ （h 2014, the National Development and Reform ssion issued an announcement for selection of reliminary research projects for the ＂13th Five-Year ereafter referred to as ＂The Announcement＂）     

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 latest scientific     

Contamination of animal feed and food from animal origin with mineral oil hydrocarbons

Oils and fats used for the production of animal feed can become contaminated with mineral oil material originating from gas oils (C₁₈-C₃₅) or synthetic oils (poly alpha olefins, C₂₅ to beyond C₄₅). An important cause is assumed to be the discharge of waste oils, such as motor oil and hydraulic oils. Mineral oil material was analysed by on-line LC-GC-FID directly in the fat or in a raw extract from animal feed or foodstuffs. In Switzerland in summer/autumn 1999 concentrations in oils and fats for feed production were often found to be between 100 and 1000mg/kg. In the feeds, the average concentration was around 100mg/kg with values ranging up to a maximum of 1000mg/kg; few samples were free of contamination. In animal body fat, the average concentration determined in summer 1999 was 25mg/kg, with a maximum of 150mg/kg, although in samples from December 1999, contamination was substantially lower. In the fat phase of eggs, the average concentration was 30mg/kg, with a maximum of 80mg/kg. Paraffin oil is used for feed production, which may account for part of the contamination problem (e.g. eggs).