共查询到20条相似文献，搜索用时 281 毫秒
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泡桐属木材的微纤丝角和结晶度 总被引：5，自引：0，他引：5
8种泡桐木材纤维次生壁S_2层的微纤丝角平均为12.52°;纤维素相对结晶度平均为46.4%。从这两项指标来看,南方泡桐和泡桐(白花泡桐)木材具有较为优良的材质。12年生毛泡桐木材的S_2层微纤丝角由髓往外,随着树龄的增加而角度增大,而纤维素相对结晶度则减少。 相似文献
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泡桐优良无性系的推广 总被引：1，自引：0，他引：1
泡桐优良无性系的推广梁作（华中农业大学林学系武汉４３００７０）关键词：泡桐，无性系，推广泡桐遍及我国２３个省、市、自治区，广泛用于四旁植树、农桐间作、混交林和城市绿化，其木材当为我国传统的出口物资。泡桐是一个丰富的种群，到目前已确定１２个种和２个变种... 相似文献
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泡桐为我国的重要造林树种,总株数巳达七亿株左右,农桐间作面积2200万亩,遍及20多个省(区、市),已推广的泡桐良种约2亿多株。据估计,全国至少还可发展泡桐10亿株。如能选用优良无性系造林,木材增产的潜力是很大的。为了对已经推广的和将要推广的优良无性系的社会经济效益进行估计,就需要对泡桐的主要性状遗传力及其它遗传参数进行研 相似文献
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泡桐新无性系速生丰产栽培技术研究朱超，王昌全，陈德玲，吴乃文（泗阳县林业中心，泗阳县众兴镇２２３７００）（泗阳县科学技术委员会）我们于１９９１年引进江苏省林科所培育的１２个泡桐新无性系进行造林试验，取得了良好的结果。试验表明，采用泡桐容器苗造林，并进... 相似文献
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泡桐木材流体渗透性与扩散性的研究 总被引：11，自引：1，他引：11
本文论述了泡桐木材流体渗透性,扩散性,吸着水与自由水的吸着与吸收动力学特性,密度和干缩性以及电镜观察结果;阐明了泡桐木材具有流体可渗透及可扩散路径,有着输导流体的天然机制,水、热处理难易一般;泡桐材本身并不具有隔潮耐湿性,但由于它密度低,胀缩小,变形和开裂的可能性亦小,用它干燥后制成的箱盒容器的密封性、隔潮耐湿性较好。 相似文献
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陕西兰考泡桐木材构造和材性的研究 总被引：3，自引：0，他引：3
对陕西渭南产兰考泡桐木材构造和材性的研究表明,木材材质优良,利用价值与其它泡桐相当,其管孔式类型并非为单纯的环孔材或单纯的半环孔材,而是环孔材至半环孔材。 相似文献
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Some of the properties of particleboard made from paulownia 总被引：3，自引：0，他引：3
The objective of this study was to determine some of the properties of experimental particleboard panels made from low-quality paulownia (Paulownia tomentosa). Chemical properties including holocellulose, cellulose, lignin contents, water solubility, and pH level of the wood were also analyzed. Three-layer experimental panels were manufactured with two density levels using urea–formaldehyde as a binder. Modulus of elasticity (MOE), modulus of rupture (MOR), internal bond strength (IB), screw-holding strength, thickness swelling, and surface roughness of the specimens were evaluated. Panels with densities of 0.65 g/cm3 and manufactured using a 7-min press time resulted in higher mechanical properties than those of made with densities of 0.55 g/cm3 and press times of 5 min. Based on the initial findings of this study, it appears that higher values of solubility and lignin content of the raw material contributed to better physical and mechanical properties of the experimental panels. All types of strength characteristics of the samples manufactured from underutilized low-quality paulownia wood met the minimum strength requirements of the European Standards for general uses. 相似文献
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泡桐木改性处理技术研究综述 总被引：5，自引：1，他引：4
介绍了对泡桐木变色的不同看法;对现有的防止泡桐木变色和变色后泡桐木处理人法的优缺点加以概述;对泡桐材改性方面的最新研究──泡桐木表面强化技术和泡桐木的阻燃研究技术作厂介绍;分析厂泡桐木改性发展的趋势。 相似文献
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以2年生5种四倍体泡桐为材料，研究其光合作用、材积生长量、接干长度、比叶重（ SLW）等指标间的差异。结果表明，5种四倍体泡桐叶片的净光合速率（ Pn）、气孔导度（ Gs）、蒸腾速率（ Tr）、胞间CO2浓度（ Ci）光合因子的日变化规律相同。9月份叶片的Pn、 Gs、 Tr、 Ci日变化为单峰曲线，四倍体豫杂一号泡桐（ TF4）的最大净光合速率高于其余4个种。此外，四倍体毛泡桐（ T4）的树高生长量和接干高增长量、 TF4的胸径生长量和比叶重增长量、四倍体南方泡桐（ A4）的材积增长量最大。5种四倍体泡桐的树高、胸径、接干、材积的相关性表明，材积与胸径呈正相关关系，相关性显著；树高与比叶重呈正相关关系，但相关性不显著。 相似文献
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泡桐干形培育研究进展 总被引：31，自引：3，他引：28
在我国北方泡桐栽培区由于泡桐顶芽在冬季枯死,通过假二叉分枝的方式进行自然接干,造成出材率低,尖削度大,树干形数小,给泡桐的木材生产带来了巨大的损失。为此我国的泡桐科研工作者经过近４０年的努力,对泡桐干形进行了遗传改良,并在此基础上,围绕干形培育对泡桐的高干壮苗、人工接干、修枝、栽培密度与干形、混交与干形及其上述栽培管理措施与泡桐丛枝病的关系等问题进行了一系列研究。本文对我国泡桐干形培育的上述研究进行了综述,并对泡桐干形培育若干亟待解决的问题进行了讨论。 相似文献
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《林业研究》2017,(4)
The vibrational performance of wood materials critical affects the acoustic quality of a lute. The purpose of this research was to apply a multiple choice model to predict the quality of musical instruments based on data on lute soundboard vibrational properties of Paulownia wood.In the lute production, lute material selection mainly depends on the subjective evaluation of technicians, which is not only inefficient, but inaccurate. In this study, nine lutes were fabricated. Using the multiple selection model,the lute tone quality was predicted by the soundboard wood vibration data. Compared with the actual value, the dependent value predicted by the count of observations with the maximum probability had 22 erroneous judgments. The model precision is 87.78%. The results confirmed that the prediction model can be used as a guideline for the selection of the soundboard wood in musical instrument plants. 相似文献
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兰考泡桐木材成分的变色行为及其变色过程 总被引：12，自引：0，他引：12
从兰考泡桐木材的含水甲醇浸提物分离出梓醇、泡桐素和芝麻素三种成分,在不同条件下进行模拟变色试验。结果显示,ｐＨ值是影响梓醇变色的主要因素,光照和氧气同时作用可导致泡桐素和芝麻素变色。温度和湿度变化对兰考泡桐木材成分变色也有明显影响。泡桐木材变色是多种因素共同作用的结果。根据对实验事实的分析,提出了这些成分在变色过程中可能发生的一系列反应。 相似文献
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ZHAO Rongjun FEI Benhua JIANG Zehui Research Institute of Wood Industry Chinese Academy of Forestry Beijing P.R.China 《中国林业科技(英文版)》2007,6(3):33-39
In order to better understand the reasons why eucalypt veneer checks easily and severely, wood samples of three eucalypt species were selected, and their anatomical and physical properties were examined according to conventional methods and the national standards. The effects of variances in cell wall thickness of wood fibre and vessel, and diameter of the cell lumen as well as the tissue ratio on the quality of plywood veneer were analysed. The results show that： 1） There is a great difference in fibre cell wall thickness and diameter of the cell lumen between early wood and late wood of Eucalyptus delegatensis. 2） E. obliqua has a high wood fibre tissue ratio and the thickest fibre cell wall, but the difference inthe fibre cell wall thickness between early wood and late wood is the smallest. 3） The wood fibre tissue ratio of E. regnans is smaller than that of E. obliqua, and its wood fibre cell wall isthe thinnest and there is only a very small difference in fibre cell wall thickness between early wood and late wood. The difference inthe diameter of wood fibre cell lumen among early wood, transition area and late wood is also small： 4） E. delegatensis has the highest tangential shrinkage rate and radial-tangential shrinkage rate, andE. obliqua has the lowest. It is the variability of wood anatomical properties of these species that cause the difference in the veneer shrinkagei and then affects plywood veneer quality. 相似文献