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软木是从栓皮树上采剥的树皮,是一种天然可再生的生物质材料。通过对软木的动态黏弹性进行研究,可以揭示许多关于软木材料结构和分子运动的相关信息。本试验主要运用动态力学分析技术研究了栓皮栎软木的动态黏弹性,并和国外栓皮槠软木进行了对比。结果表明:在不同测试频率条件下,再生栓皮栎软木的储能模量(E~')均随温度升高而呈现降低趋势,损耗因子(tanδ)曲线主要出现了3个明显的损耗峰,对应的3个损耗过程分别由软木脂无定形区发生玻璃化转变、软木中有关成分发生熔融和吸着水的损失、纤维素和半纤维素发生热软化或降解所引起。再生栓皮栎软木分别沿轴向、径向和弦向进行拉伸测试时,E~'、损耗模量(E~″)和tanδ曲线的变化趋势基本一致,但在相同测试温度下,E~'和E~″在3个方向存在明显差异。在本试验条件下,栓皮栎和栓皮槠软木存在不同温度的损耗峰,主要表现为初生和再生栓皮栎软木的tanδ曲线分别在-10和-19℃出现一个损耗峰,而再生栓皮槠软木对应的损耗峰出现在14℃。 相似文献
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<正> 栓皮槠又称欧州栓皮槠(Quercus Suber L.),几个世纪以来,栓皮槠成为有较大价值的商品树种且在逐渐发展,其树皮是丰富优质的栓皮--软木原料,结的果实橡子可加工成上好的饲料和他副其产品。近年来,人们把它植于公园、街道、村庄当遮荫树与风景树来观赏。栓皮槠属常绿乔木,皮厚果丰,冠大干矮,修枝后萌发力强,也可随意造形。厚绿的叶片,伸着宛延的树枝,体形多姿异态,色泽飘逸,如伞遮盖地面。它适应性强,易于栽植,生长较快。美国政府与林木私人种植者为它的发展做了不懈地努力,除取得了栓皮、橡子的商品巨额利润外,尚获得了绿荫和美的享受。故此,目前乃至将来它会得到人们的青睐和喜爱。 相似文献
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<正> 一、前言软木是含有大量木栓组织的树皮。栓皮栎(Quercus Variabilis BL)、栓皮储(Qu-er?us Suber)、黄波萝(Phellodendron amurense)是目前世界上生产软木的三个主要树种。栓皮储主要分布在地中海沿岸的葡萄牙、西班牙、阿尔及利亚、意大利、摩洛哥、法 相似文献
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软木是以栓皮栎的栓皮为原料,具有弹性、保温隔热、防滑耐磨、消音减震、安全无毒等特性的一种可再生绿色材料,产品广泛用于国计民生等重要行业和领域。文中介绍了世界软木资源分布情况、软木用途和产业趋势,综述了国内外软木细胞结构、化学成分、工艺与产品研发等概况,在比较欧美各国与我国软木产品标准制定/修订现状的基础上,概述了我国对现行软木纸标准LY/T 1320-2010和软木纸试验方法LY/T 1321-2013的修订研究过程。提出了加强我国软木研发的建议,即紧跟软木脂研究国际前沿,加大软木脂基础与应用技术研究;加强软木行业标准建设,实现软木产品标准国际化、单项化、功能化;加强软木产品开发利用以及软木资源的培育以提升我国软木产品竞争力,促进我国软木行业健康快速高效发展。 相似文献
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西安林化厂开发出新型软木橡胶地板新产品,日前已小批量投放市场。倍受用户青睐。软木橡胶地板是以优质天然软木(栓皮)为主要原料,以无污染型橡胶做胶合剂制成的新型高级弹性地板贴面砖,产品主要性能指标达到了国际标准 ISO3813,填补了国内空白。由于软木具有奇特的多孔薄壁细胞结构,产品具有优异的防滑性能和吸音、隔振效果, 相似文献
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Summary For champagne and other sparkling wines, agglomerated cork stoppers are used, lined at the bottom with two superposed discs
of natural cork. The quality evaluation of champagne stoppers in the high quality range was made in relation to the porosity
of the visible surface of the bottom cork disc using image analysis techniques. The average porosity coefficient was 3.1%.
Most pores were small but approx. 75% of the total porosity comes from pores with an area >0.25 mm2. Pores with a high visual impact (>2.0 mm2) are less than 1% and were not determinant to the total porosity. The quality grading could be made using porosity coefficients
as selection criteria to discriminate between classes. In comparison to commercial grading, the use of quantified porosity
parameters for quality class definition allowed higher within class homogeneity and between class differentiation.
Received 29 January 1998 相似文献
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Jose R. Gonzalez-Adrados Maria C. Garcia-Vallejo Maria J. Caceres-Esteban Jose L. Garcia de Ceca Florentino Gonzalez-Hernandez Rosa Calvo-Haro 《Wood Science and Technology》2012,46(1-3):349-360
Fourier transform infrared (FTIR) spectroscopy was applied to determine the type of surface treatment and dose used on cork stoppers and to predict the friction between stopper and bottleneck. Agglomerated cork stoppers were finished with two different doses and using two surface treatments: P (paraffin and silicone), 15 and 25?mg/stopper, and S (only silicone), 10 and 15?mg/stopper. FTIR spectra were recorded at five points for each stopper by attenuated total reflectance (ATR). Absorbances at 1,010, 2,916, and 2,963?cm?1 were obtained in each spectrum. Discriminant analysis techniques allowed the treatment, and dose applied to each stopper to be identified from the absorbance values. 91.2% success rates were obtained from individual values and 96.0% from the mean values of each stopper. Spectrometric data also allowed treatment homogeneity to be determined on the stopper surface, and a multiple regression model was used to predict the friction index (If?=?Fe/Fc) (R 2?=?0.93). 相似文献
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《Forest Ecology and Management》2001,141(3):251-258
The effect of the removal of cork was studied in 11-years old cork oak trees (Quercus suber L.), growing in favorable conditions, in relation to phenology and radial growth during two years. Longevity of leaves was 14–15 months (1996, 1998) and 10 months (1997). Bud burst started in mid-February and leaf flushing in April, extending until June. Neither a distinct two-period flushing nor an autumn bud burst or leaf flushing were observed. Radial growth started in mid-April and continued until the end of November, with the maximum growth in June and July. In trees with the removal of cork, leaf abscission occurred a little earlier and new branches had on average 23% fewer new leaves. The radial growth of the trees and its general seasonal pattern were not affected by cork removal in the year of removal or in the year after. The only observation was a shift of the maximum radial growth rate from June to July for the trees where cork had been removed. 相似文献
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Botryosphaeria canker of cork oak (Quercus suber L.), caused by Botryosphaeria corticola, is a well-known factor contributing to the decline of this forest species and is a serious disease in the main cork-producing countries of the Western Mediterranean basin. In this work, fungicides with the potential for controlling the disease were selected using a combination of in vitro tests and field trials. Fourteen fungicides in different chemical families were tested in vitro to evaluate their effect on inhibition of mycelial growth. The most effective fungicides were benomyl, carbendazim, cyprodinil + fludioxonil, thiabendazol and thiophanate-methyl; these compounds were then further tested under field conditions. In the field trials, carbendazim and thiophanate-methyl were the most effective fungicides, as shown by efficacy indices, in reducing debarked trunk surface affected by cankers (76% and 50–65%, respectively). These results suggest that the occurrence of Botryosphaeria canker on cork oak can be reduced effectively with the application of selected fungicides after cork removal from the trees. 相似文献
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H. Pereira 《Wood Science and Technology》1988,22(3):211-218
Summary The chemical composition of cork from Quercus suber L. was determined for virgin cork and for reproduction cork. Average chemical composition of virgin cork is: ash 0.7%, total extractives 15.3%, suberin 38.6%, lignin 21.7% and polysaccharides 18.2%. The carbohydrate composition shows that glucose represents 50.6% of all monosaccharides, xylose 35.0%, arabinose 7.0% and galactose and mannose, respectively, 3.6% and 3.4%. Reproduction cork has a composition similar to virgin cork. For the cases studied, reproduction cork had however less extractives and a higher amount of suberin. Significant differences were found for the chemical composition of virgin cork in relation to location of extractives and polysaccharide content. The between-tree variability was large and a variation within the tree was also recorded.The author is grateful for the help of collaborators throughout the chemical analysis of the many samples: Joaquina Ferreira, A. Velez Marques, M. Lurdes Ferreira, Rosa Amorim and Célia Constâncio.The work was financially supported by the Instituto de Ciência e Tecnologia dos Materiais (ICTM), Lisbon, Portugal 相似文献
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Quercus variabilis Blume, the Chinese cork oak, is an oak species with a thick cork outer bark. The cork is exploited at a limited scale in China and considered of lower quality than the commercial cork from Quercus suber. We studied an industrial cork granulate feedstock of Q. variabilis in relation to cellular structure and chemical composition and compared it to Q. suber cork under a material’s perspective. The cork of Q.variabilis has 1.1 % ash, 9.6 % extractives, 34.8 % suberin and 19.1 % lignin. The monosaccharide composition with shows a predominance of hemicelluloses: glucose 42.8 % of total neutral sugars, xylose 27.5 %, arabinose 15.4 %, galactose 9.0 %, mannose 4.0 %, rhamnose 1.2 %. The FT-IR spectrum shows the indicative peaks of suberin. The composition is overall similar to that of Q. suber cork. Q. variabilis cork has the typical cellular characteristics of bark cork tissues with a regular and radially aligned structure of cells without intercellular voids. Solid volume fraction was estimated at approximately 16 %. Compared with Q. suber, the Q. variabilis cork cells are smaller, the cell wall undulation and the overall row alignment less homogeneous, the cell surface is irregular and the solid volume proportion higher. The characteristics of Q. variabilis cork support its use as a cellular material for sealing, insulation and energy absorption, but the overall quality is lower than that of Q. suber cork. The negative impact of the higher density and structural lower uniformity at tissue and cell level should be evaluated for processing and product performance. 相似文献
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Paulo Joana Amaral Firmino Paulo Neves Faias Sónia Pacheco Tomé Margarida 《European Journal of Forest Research》2021,140(4):991-1004
The annual growth and the thickness of cork are known to be highly variable between trees located in the same geographical location. Researching how climate variables affect different trees within the same site is a step forward for the management of cork production since current knowledge focusses only on the average tree response. Quantile regression methodology was applied for the first time to a large data set containing measurements of cork growth, sampled in 35 stands across the cork oak distribution area in Portugal. This methodology proved to be useful for testing the hypothesis raised: does climate affect differently the annual cork growth, and ultimately cork thickness of individual trees located in the same stand? Estimating the amount of cork produced by one stand that has the required thickness for the production of natural cork stoppers is essential to support cork oak management. However, no model, before this work, had been developed to provide managers with this information. A downward parabolic relationship between annual cork growth and annual precipitation was determined for all quantiles, with optimum annual average precipitation value ranging from 1103 to 1007 mm. April to August monthly temperatures, spring average temperature or summer average temperature, showed a negative relationship with annual cork growth, in particular for lower quantiles. Maximum annual temperature was shown to negatively affect annual cork thickness, in particular for the trees under the 6th quantile. The ratio between annual precipitation and average temperature, that define the Lang index (LI), showed a downward parabolic relationship with annual cork growth. Best cork growth conditions are found for Lang index values around 60, corresponding for the transition between semi-arid climate and humid climate. The application of the final model developed for estimating cork thickness of an eight years’ cork growth period allowed the prediction and mapping of the percentage of cork suitable for natural cork stopper production. It showed that higher values are expected in the Southern and Central coastal regions and along the Tagus River basin. The Northern coastal and mountain regions, characterised by Lang index values higher to 60 (humid climates), present lower estimated values for the percentage of cork suitable for natural cork stopper production. The estimated values are expected to be reduced under climate change scenarios in the Southern and Central coastal regions.
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Variations in tree ring growth of Quercus suber L. were analysed using dendrochronological techniques on cork oak discs from trees harvested in the cork producing region
of Alentejo, Portugal. A tree-ring chronology containing a strong common signal and covering the period from 1970 to 1995
was build for ca. 30-year-old cork oaks never submitted to cork harvesting using 14 trees that crossdated satisfactorily out
of 30 sampled trees. The tree ring indices correlated positively with September temperature (r = 0.48, P < 0.05) and very strongly with precipitation totals from previous October until current February (r = 0.82, P < 0.001) showing that the water stored in the soil during the autumn and winter months prior to the growing season has a
primordial effect on the growth of the given season. The effects of cork harvesting were analysed by comparing mean ring width,
mean annual vessel area, vessel density (n°vessels/mm2), and vessel coverage (percentage of transverse surface occupied by vessels) between three mature cork oak trees and three
young trees, for the period from 1987 to 1996, corresponding to the growth between two consecutive cork removals in the case
of mature trees. In 1988, 1989 and 1996 (corresponding to the first and second years after cork removal, and 1996 to a year
of cork removal), the ratios between ring widths of young versus mature trees was twice that for the rest of the period. However,
an effect of cork removal indicated by eventual alterations in vessel size and distribution in the wood rings corresponding
to the years 1988, 1989 and 1996 in the mature cork oaks was not observed. 相似文献
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研究不同规格软木材料的吸水性,及加入渗透剂和抽真空-加压两种处理方式,对软木材料吸水率的影响。结果表明:软木材料的吸水率随其体积的增大而减小;渗透剂对提高软木粒子的吸水率有一定作用,而抽真空-加压处理的效果不显著。 相似文献