Surface treated cellulose fibres in flame retarded PP composites

Polypropylene-based composites were prepared containing non-treated and various treated cotton fibre and wood flakes. A correlation was observed among the fibre treatment and compounding parameters, mechanical and discoloration properties. The structural changes in fibres were demonstrated by Raman spectroscopic and DSC measurements. The possibility for forming cellulose fibre containing flame retardant composites was also investigated. The efficiency of various treatments on compounding, discoloration and mechanical properties enhance in the following order: no treatment < non ionic surfactant < reactive silicone segment containing non ionic surfactant < special silylation treatment. The best results obtained with the special silylation treatment were explained with the more organophilic character and by the thermal stability of the treated fibres. Cellulose fibre as a polyol-charring component and ammonium-polyphosphate together constitute a high performance intumescent flame retardant system in the PP matrix.     

木材静压大变形本构关系研究

在研究木材静态缓冲特性的基础上,对实验数据进一步分析处理,得到了木材静压大变形情况下顺纹和横纹方向的静态本构关系。     

治疗冠心病中药的微量元素测定

对治疗冠心病中药丹参、降香、红花、茯苓及复方丹参注射液中铜、锌、铅、镉的含量 进行了测定。结果表明,其中必需微量元素铜、锌含量均比有害元素铅、镉的含量要高出1－2个数量级,其铜／锌比值与正常人血清铜／锌比值能较好地吻合,镉／锌比值较低。     

不同提纯方法对竹木质素结构特性的影响分析

应用UV、FT-IR、GPC和GC-MS研究了不同制备方法提纯的慈竹磨木木质素(milledwoodlignin,MWL)的结构特性,结果表明慈竹木质素属于愈疮木醇-芥子醇-对香豆醇(GSH)型木质素,竹木质素侧链含有少量的α-β碳碳双键,慈竹中含有数量相当多的紫丁香基结构单元,且紫丁香基结构单元的含量高于愈疮木基结构单元的含量;慈竹木质素含有酯键,主要是对-香豆酸的羧基与酚羟基发生酯化反应生成的.经超声波辅助碱抽提的木质素相对分子质量分布比较均匀,乙醇抽提可以增加木质素的重均分子质量.慈竹木质素的紫丁香基单元(S-unit)存在大量的β-O-4的联接,竹木质素中松柏醇和松柏醛以及香豆醛和香豆酸的含量很少,木质素H单元的侧链γ-碳存在少量醚键联接,愈疮木基单元(G-unit)和S单元的侧链γ-碳不存在醚键联接.     

阔叶树皮木醋液与木焦油有机成分的气相色谱分析

运用气相色谱对阔叶树皮木醋液及木焦油水提取液的有机成分,如醇类、羧酸类、酮类、酚类等进行了定量分析.结果表明,木醋液随着蒸馏处理,甲醇、乙醇、丙酮等低沸点物质主要分布在前馏液中,2,6-二甲氧基苯酚、甲基环戊烯醇酮、2-甲基-3-羟基-4-吡喃酮等高沸点物质主要分布在残馏液中.通过阔叶树皮木醋液及木焦油水提取液的两种主馏分所含有机成分的定量分析比较,表明除甲醇、乙酸、丙酸、2-呋喃醛等成分以外,二者具有相似的化学成分组成.     

Microspectrometric Investigation of Petrified Wood from South-Eastern Poland

 The investigation of the interesting collection of the petrified wood from Bondyrz, Roztocze, south-eastern Poland, has been continued. Two kinds of microprobes such as electron microprobe from the Catholic University of Lublin and synchrotron-based X-ray microprobe from LURE, Orsay, were applied to detect the elements associated with the main component – silica and their spatial distribution and interrelations. The distribution of carbon in the petrified material has been established, which is important since that element is the main remains from the history of the trees. The carbon distribution was characteristic – it concentrated on a place of primordial dark wood. The distribution patterns of the other elements were either similar to that of carbon (Cu, Pb) or they concentrated in separate inclusions (Fe, Al, K, Na, Ca). The replicating mode of the original wood pattern in silica and carbon-containing material was explained. Some indications about the composition of the primordial petrifying solution, the rate of the petrifaction process and the recent coloration of the sample could be concluded from the compositional patterns of silica. The boundary between totally and partially petrified zones could be well observed. Received October 2000. Revision March 6, 2001.     

Formaldehyde‐Free Wood Adhesives from Decayed Wood

Summary: Extensive studies using mussel adhesive protein as a formaldehyde‐free, strong, and water‐resistant adhesive model revealed that a combination of a polymer with catechol moieties and a polymer with amino groups could serve as a strong and water‐resistant wood adhesive. This study demonstrated that the treatment of abundant and readily available brown‐rot‐fungus‐decayed wood with NaBH₄ followed by mixing with polyethylenimine resulted in a formaldehyde‐free, strong, and water‐resistant wood adhesive.

Lignin is demethylated by brown‐rot fungi and then reduced using NaBH₄.     

永乐大钟梯形木架稳定性初探

对北京市大钟寺悬挂永乐大钟的梯形木架结构的稳定性进行了初步分析. 根据弹性结构稳定 性理论的能量法和中国古建筑结构``卯榫'接头抗弯性能的简化的本构模型,采用``对比法 '分析了二维梯形木架的结构稳定性;结果表明中国古建筑木架结构的``收分'形状设计对 增大木架稳定性有很大作用, 立柱``侧角'越大,稳定性越好. 收分形式设计凸现 中国古代工程技术人员的聪明智慧.     

???????????????о?

木材声发射信号与其内外部损伤情况存在一定的定量关系. 依据损伤理论和含有裂 纹以及缺陷的木材不同阶段的声发射特征,分别探讨并建立了受交变载荷和单向静载荷情况下以声发 射特征参数表示的木材损伤演变模型. 分析结果与木材的实际情况相一致,表明以声发射特 征参量建立的木材损伤演变模型对木材的损伤预测具有提前性与敏感性,而且木材的不均匀 性是其提前破坏的主要原因之一.