兰旗榆——一个在干旱草原区很有发展潜力的造林树种

兰旗榆为白榆的一个地理生态变种,在锡盟浑善达克沙地及其南缘的镶黄旗、正镶白旗、正兰旗等地区生长表现突出。该树种较之其它的白榆品种具有抗旱、抗寒、抗风沙,物候期早,所需积温低以及生长迅速等优良特性,对我区北部干旱草原气候生态条件适应能力强,在草原造林中有着其它树种不可替代的地位和作用,建议大力推广。     

我国发展休闲渔业的SWOT分析与对策

我国发展休闲渔业．已引起全国水产界的兴趣。作者应用SWOT方法分析我国发展休闲渔业的机遇和挑战。采取必要的对策。     

马来海松酸型聚氨酯烘漆耐热性研究

以马来海松酸酯多元醇为原料，制备了马来海松酸型聚氨酯烘漆，利用热重法，讨论了不同原料组分及配比，固化温度和固化时间等因素对烘漆耐热性的影响，另外，还利用ＤＳＣ，对二月桂酸二丁基锡对封闭异氰酸酯组分热解封温度的影响了讨论。     

基于PAT—tree的中文关键词自动检索模式的研究

利用可变长语言模型对中文文档的关键词进行准确识别是中文信息处理中的一个重要问题.由于不存在n元语言模型的截断效应,对关键词检索的长度没有限制,因此增加了关键词识别的难度.利用PAT-tree技术设计了一个改进的可变长统计语言模型对中文文档中的关键词进行识别.在该模型基础上进行相关性检测实验.实验结果表明基于PAT-tree的改进语言模型能更好的识别关键词.     

北美红杉生态因子的研究状况

北美红杉自然分布范围狭窄 ,通过 10 0多年的努力 ,北美红杉已在 2 0多个国家成功引种。许多学者对北美红杉的生态因子进行了大量的研究。为了解国内外的研究状况 ,从影响北美红杉分布和生长的光、温度、雾、土壤 4个重要的生态因子出发 ,结合该树种自然分布区的生态环境 ,对其研究成果进行了概括和分析     

Protection and fastness of green color of moso bamboo (Phyllostachys pubescens Mazel) treated with chromium-based reagents

The attractive green color of moso bamboo (Phyllostachys pubescens Mazel) culms fades without chemical treatment. Chromated copper arsenate (CCA) has been used to protect the green color of bamboo, but CCA is harmful to factory workers and the environment. To overcome the toxicity of arsenic in CCA, two chromium-based formulas developed by the authors, chromated copper phosphate (CCP) and chromated phosphate (CP), were evaluated for their protection of the green color of moso bamboo. The results revealed that bamboo treated with CP had a greener color than those treated with CCA or CCP. The concentration, treatment time, and CrO₃/H₃PO₄ ratio in CP solution greatly affected the color of moso bamboo culms. The attractive green color, which resembles the color of fresh-cut moso bamboo, was obtained by treating bamboo with 2% CP solution at 60°C for 3h, using a 11 CrO₃/H₃PO₄ ratio in aqueous solution. In addition, the CP-treated moso bamboo exhibited excellent green color fastness in both accelerated ultraviolet lightfastness testing and outdoor weathering exposure.     

北美红杉种子育苗试验

对不同种源的北美红杉种子作不同试剂浸种处理和控制不同发芽温度的发芽试验 ,以及开展不同种源种子的播种育苗试验 ,结果表明 :种子发芽率和发芽势最好的方案是用SYA6种源 ,种子经 10 0 0mg/L的KMnO4溶液浸泡 12h ,发芽温度采用 2 0℃。参试的 3种因素中 ,种源因素对种子发芽率和发芽势影响显著 ;北美红杉各个种源苗木生长迅速 ,1年生苗木除苗木侧根数外 ,各种源间苗木的苗高、地径、主根长度、苗木鲜重和苗木干重差异极显著     

Water transport in wood particle material

An analogy between water flux and the field of temperature gradient in a column of wood fuel chips was discovered by these experiments. The heat—mass transfer coefficient was determined by least squares method. An equation relating water flux and temperature gradient was developed and it was demonstrated that the temperature gradient was the main driving force for water transport. The mechanism was evaporation—condensation of water vapor through natural convection in air phase. The study gives a theoretical explanation for analyzing the problem of water transport in wood particle material.     

Wood Moisture Content Measurement by X-Ray Exposure Method

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林木引种技术探讨

通过对林木引种基本理论和技术的讨论,提出了实现林木良种化的基本途径.