共查询到20条相似文献，搜索用时 171 毫秒
1.
把树脂单体、添加剂等浸入到木材中,木材受热后,树脂单体在木材内部聚合,与木材纤维形成交联网状结构,从而改善了木材的物理性能和化学性能。 相似文献
2.
3.
4.
为探讨浸注工艺对木材增重率的影响,以PF树脂为浸注材料,以树脂浓度、压缩次数、保压时间、浸渍时间和压缩率为试验因素,采用单因素试验方法在平压浸注装置上对杨木试件进行了浸注填充。结果显示:2次压缩较1次压缩,杨木木材增重率增加了20. 2%;保压时间从0 min延长至10 min,杨木木材增重率增加了11. 5%;浸渍时间从1 h延长至2 h,杨木木材增重率提高了8. 8%;再增加压缩次数、延长保压时间和浸渍时间,杨木木材增重率均变化不大;而杨木木材增重率随PF树脂浓度和杨木木材压缩率增加呈线性增加,PF树脂浓度与压缩率对杨木木材增重率具有显著影响。因此选择压缩次数为2次,保压时间为10 min,浸渍时间为1 h,PF树脂浓度与杨木木材压缩率由改性木材的用途决定。 相似文献
5.
水煮处理是对木材进行预处理的一个重要方式。木材在水煮处理过程中,在高温高湿的条件下,松香受热软化,流动性增强,并移出木材。本研究通过分析不同水煮处理时间和不同后期处理条件下树脂脱除和分布规律,探讨研究简单和低成本的松木脱脂工艺。通过实验分析,得出木材水煮处理时间在8h以下时,试件中树脂分布呈芯层高表层低,随水煮处理时间延长,试件平均树脂含量显著降低。处理时间达到8h时,随着处理时间增加,树脂含量变化不明显。 相似文献
6.
为提升人工林速生材的尺寸稳定性,以人工林尾巨桉（Eucalyptus urophylla×E. grandis）木材为研究对象,采用二羟甲基二羟乙基乙烯脲（DMDHEU）树脂进行真空-加压浸渍处理,分析树脂浓度和加压压力对木材增重率、密度的影响及增重率对木材尺寸稳定性的影响。结果表明,树脂浓度为30%、加压压力为1.2 MPa时,处理材增重率最大（23.85%）;各密度均最高,其中基本密度比未处理材高出26.9%,气干密度高出19.9%,全干密度高出19.8%;气干抗缩率、全干抗缩率、抗胀率和抗吸水率均最大,分别为72.9%、46.6%、53.5%和65.5%。木材增重率和密度均随树脂浓度和加压压力的增加而增加。树脂浓度高于20%、加压压力≥0.9 MPa时,木材增重率和密度增速均减缓。树脂浓度对木材增重率和密度的影响高于加压压力。树脂浓度相同、加压压力≥0.9 MPa时,木材增重率基本保持不变。相同压力下,处理材的尺寸稳定性随增重率增加而增加;压力≥0.9 MPa时,增重率达到9%～10%左右,木材抗胀（缩）率增速减缓。增重率相近、加压压力增加时,木材抗胀（缩）率有所增加,木材抗吸水... 相似文献
7.
水性树脂底漆对木材表面润湿性能的影响是决定木器涂装质量的关键因素。为了给木器水性漆涂装提供基本依据,选择松木、杉木、橡木、奥古曼和非洲紫檀5种木材,研究水性丙烯酸树脂底漆、水性丙烯酸改性聚氨酯底漆、双组分水性丙烯酸树脂对其表面润湿性能的影响。采用正交试验设计方案,以漆种、底漆质量分数、树种和干磨砂纸粒度为影响润湿性的因素,分别研究水性树脂底漆在木材弦、径切面的接触角大小和5种木材弦、径切面的孔槽比,分析影响木材表面润湿性的因素及原因。结果表明:4个因素水平中,底漆质量分数和漆种对木材表面润湿性的影响非常显著,树种对其影响显著,干磨砂纸粒度对其无显著影响;5种木材径切面的孔槽比高于弦切面,针叶材弦、径切面的孔槽比高于阔叶材,径切面的润湿性优于弦切面,针叶材表面润湿性优于阔叶材;此外,单组分水性树脂底漆在5种木材弦、径切面的润湿性优于双组分水性树脂底漆。因此,在木器水性漆高质量涂装中,对于不同木材种类应该选择合适的水性涂料及最优质量分数,才能保证涂装中底漆良好的质量。 相似文献
8.
9.
10.
11.
《中国林业科技(英文版)》2009,(1)
Based on the introduction of the Sino-Russian timber trade and the history about timber export in Russia,the paper gives the reasons for the adjustment in Russian timber export and its influence on timber import in China.Finally countermeasures against Russian adjustment in timber export tariffs are proposed. 相似文献
12.
木材储备基地及其多功能森林经营建设对策 总被引：2，自引：2，他引：0
木材战略储备基地作为林业产业发展的重大举措被列入我国“十二五”林业发展规划,以应对我国木材自产不足、外供不济的安全保障问题,但面临速生丰产林用地有限、社会对森林综合需求增加、生产成本上升、效益低下等因素制约。文中在分析木材储备的特征及其森林经营需求的基础上,提出以林分状态存在的活立木储备是低成本、环境友好型、有战略意义的木材储备,而且木材储备基地是一种以物质生产功能为主导的多功能用材林模式;在此基础上,进一步提出了通过建设有生命活力和结构稳定的用材林生态系统来实现有经济效益的木材战略储备基地的多功能森林可持续经营对策。 相似文献
13.
14.
预测2010年东北、内蒙古地区木材的供需状况。到2010年区域木材供给量为4808.50万m^3,其中区域木材产量占58%,从俄罗斯进口的木材占42%。木材的需求量为6475.81万m^3,供需缺口达1 667万m^3。不考虑区域外的需求及国外的需求,东北、内蒙古地区的木材供给还是能够满足本地区经济建设需求的。木材供需的缺口对本地区木材需求不会造成太大的影响,但却对其他地区对木材的需求将产生重要影响。对于东北、内蒙古地区而言,俄罗斯远东地区是理想的木材供应基地,应规范企业的对俄木材贸易,将这一地区开发成可持续的木材供应市场。 相似文献
15.
Klaus Zimmermann Tobias Schuetz Holger Weimar 《European Journal of Forest Research》2018,137(4):463-475
In this study, we explore the determinants of forest enterprises’ timber storage accumulation after severe storm events. The explanatory power of variables reflecting economic, institutional and tree species-related factors is tested via econometric analyses. Timber storage accumulation is assessed conducting a weighted multiple linear regression analysis. In addition, the moderating effect of timber price alterations on timber storage accumulation is tested employing timber price alterations as a moderator variable in a hierarchical regression analysis. The results show a linear positive relation between forest enterprises’ damaged and stored timber quantities. It was found that coniferous timber was stored to a greater extent than non-coniferous timber which can be explained by higher storm damage as well as better suitability for multiyear storage. State forestry stored the highest shares of damaged timber, followed by municipal and private forest enterprises, which can be explained as a countervailing measure. A further central finding of our study is that the timber price drops after storm events act as a moderator variable on the relation between damaged and stored timber quantities. Hence, empirical timber price reactions help to improve estimation accuracy regarding the shares of damaged timber which are stored. Derived from our results, we find timber storage accumulation to be a common practice by forest companies to mitigate revenue losses caused by extreme storm events. As coefficients vary strongly among the analyzed variables’ categories, we consider case-specific storage accumulation estimations to be crucial for improving the accuracy of national wood and timber accounting, but also for a full view on storm-related economic damage in the forest sector. In addition, it is likely that capturing the proportions of timber storage in forests will gain relevance in the future, since forest damage from natural disturbances is expected to increase as a consequence of climate change. 相似文献
16.
17.
Okumu Gordon Wanyama Kei Sawata Takuro Hirai Akio Koizumi Yoshihisa Sasaki 《Journal of Wood Science》2012,58(4):315-321
In this study, an experimental study was conducted on the nailed timber–plywood–timber joints extended from the standard wall–floor joints of wooden light frame constructions, where the bottom plates of shear walls are nailed to the floors consisting of joists and floor sheathings nailed to them. The principal conclusions are as follows: The allowable lateral resistance of the nailed timber–plywood–timber joints can roundly be estimated by neglecting the plywood panels if their densities are higher than those of the timber main-members and they are fastened effectively onto the timber main-members. The stiffness of the timber–plywood–timber joints is less than that of the control timber–timber joints, which is improved by increasing the number of nails used to fasten the plywood panels onto the timber main-members. The stiffness of the joints whose floor sheathings are glued onto the joists is equivalent to the control timber–timber joints. The timber–plywood–timber joints with appropriate specifications have greater energy capacity until the failure than that of the control timber–timber joints. This ensures their energy capacity, which is important in dynamic resistance, to be equivalent to the control timber–timber joints. 相似文献
18.
HU Yanjie LIN Fengming SHI Kunshan Research Institute of Forestry Policy Information Chinese Academy of Forestry Beijing P.R.China 《中国林业科技(英文版)》2007,6(2):62-73
The historical transition of timber distribution pattern in China was presented firstly with main parts of timber flows in China, which included timber markets, timber transport system and regulations of timber transport. Based on the overview on tropical timber flows in China, the trade flows of tropical timber from production and imports of tropical timber to export of tropical timber products were analyzed by vivid illustrations. At the same time, problems in timber trade flows in China were analysed in the end. 相似文献
19.
XIONG Manzhen BAO Fucheng Research Institute of Wood Industry Chinese Academy of Forestry Beijing P. R. China 《中国林业科技(英文版)》2005,4(4):84-91
INTRODUCTION Because China is deficient in forest resources, and the forest has the characteristics of low quality, uneven distribution, slow growth and severe situation of ecological environment, the ecology construction has become the first requirement in society and with the implementation of the “Natural Forest Conservation Program”, Chinese forestry is in the historic transition from timber production to ecological construction. Therefore, the timber production in China increases… 相似文献
20.
关于木材需求曲线修正法的讨论 总被引：2，自引：2，他引：0
木材需求曲线与森林环境需求曲线的价格需求弹性是不同的,后者远比前者大。在这种的情况下,用木材需求曲线近似代替计算森林环境价值,会严重低估森林环境价值,理论上有严重的缺陷。加上以木材价值替代全部森林非木材产品的价值,也会导致对森林环境价值的低估。这2个相同方向的差异累积后,导致木材需求曲线修正法严重低估森林环境价值。另外,木材需求曲线修正法也不能评价具体的涉及森林环境价值的项目,因此,没有实际的应用价值。 相似文献