穿斗式木框架受力性能研究

为研究西南地区穿斗式木结构的承载能力和变形特征,设计了单榀足尺穿斗式木框架进行水平静力单调加载试验,获得了木框架水平荷载-位移曲线关系以及木框架的整体破坏形态等,并采用ABAQUS 软件对木框架进行数值分析．研究表明木框架破坏形式表现为框架整体的严重倾斜,柱与枋本身较为完好;木框架柱顶侧移随着加载位移的增加呈线性增长关系,对称的左右立柱和瓜柱柱顶侧移基本一致;不同节点榫头同步拔出,拔榫量峰值相差较小,表现出较好的协调性;暗销节点的变形主要表现为榫头的挤压凹陷,榫头横纹方向较早地进入塑性变形阶段．卯口受压变形较小,处于弹性变形阶段．     

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。     

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.     

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.     

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.     

???????????????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.     

Determination of airborne wood dust in Button samples by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS)

Emerging concerns regarding the toxicity of inhaled wood dust support the need for techniques to quantitate wood content of mixed industrial dusts. The diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis technique was applied to the determination of wood content of 181 inhalable dust samples (geometric mean concentration: 0.895?mg/m³; geometric standard deviation: 2.73) collected from six wood product industry factories using 25?mm glass fibre filters with the Button aerosol sampler. Prior to direct DRIFTS analysis the filter samples were treated with ethyl acetate and re-deposited uniformly. Standards ranging from 125?µg to 4000?µg were prepared for red oak, southern yellow pine, and red cedar and used for quantitation of samples depending upon the wood materials present at a given factory. The oak standards spectra were quantitated by linear regression of response in Kubelka-Munk units at 1736?cm^?1, whereas the pine standards and the cedar standards spectra were quantitated by polynomial regression of response in log 1/R units at 1734?cm^?1, with the selected wavenumbers corresponding to stretching vibration of free C=O from cellulose and hemicelluloses. For one factory which used both soft- and hard-woods, a separate polynomial standard curve was created by proportionally combining the oak and pine standards polynomial regression equations based on response (log 1/R) at 1734?cm^?1. The analytical limits of detection were approximately 52?µg of oak, 20?µg of pine, 30?µg of cedar, and 16?µg of mixed oak and pine for the factory with mixed woods. Overall, the average of dry wood dust percentage of inhalable dust was approximately 56% and the average dry wood dust weight was 0.572?mg for the Button samples. Across factories, there were statistically significant differences (p?<?0.001) for the percentage of dry wood dust in inhalable dust with factory averages ranging from 33.5 to 97.6%.