最新刊期
      期 0 ， 2020
      • You Jixue,Jin Zhongwei,He Wenlong
        Issue 3, Pages: 1-4(1989) DOI: 10.19455/j.mcgy.1989.03.001
        摘要：This paper deals with the treatment of Populus wood by rising Urea Formaldehyde Concentrate to improve wood properties. Results indicate that the decay resistance, dimensional stability and mechanical properties of modified Populus wood are improved, The colour of the treated wood is light. The treated wood can be painted and used as building material to substitute Chinese fir.  
          
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      • Wu Shuhong Sun,Zhenyian
        Issue 3, Pages: 5-8(1989) DOI: 10.19455/j.mcgy.1989.03.002
        摘要：This study focuses on the effects of temperature, concentration, urea and methylolurea compounds on the pH values of NH4Cl-HCHO system. Through experiment, the results are obtained as follow: 1) the pH values of the system increase with rise of temperature and decrease with increase of formalde-hyde concentration; 2) addition of urea methylolurea compounds makes the pH value decrease by approximately 1 pH unit.  
          
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      • Liu Ruogong
        Issue 3, Pages: 8-13(1989) DOI: 10.19455/j.mcgy.1989.03.003
        摘要：The curing reaction of two kinds of UF resins has been studied, namely, for plywood （F/U=1.7） and for particleboard （F/U=1.63）, in the presence of NH4Cl hardener The result shows that there is a clear exothermic peak below 100℃ with NH4Cl. The temperature of the. peak （Tp） hardly changes at a definite time range, bout the exothermic heat （ΔH） and the height of the peak lower with time The Tplowers and the height of the peak rises with increase of NH4Cl amount, when the amount is about 1.5%（based dry resin）both of them are no change.The exothermic peak is concerned with the disappearance of the group-CH2OH, and then a primary curing reaction of UF resin takes place. The curing reaction order is 1.5, the active energy is 80 KJ/mol with 1.7% NH4Cl （based dry resin） according to kissinger’s method by DSC.  
          
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        发布时间：2021-03-12
      • Ye Kelin
        Issue 3, Pages: 13-19(1989) DOI: 10.19455/j.mcgy.1989.03.004
        摘要：In this article, the state of stress in tensile-shear Strength-testing Pieces of plywood wasanalyzed with the theory of Single—lap joint. The results showed that there are three kinds of stresses in the testing pieces, the tensile stress in the face veneer and the shear stress in the coreveneer, both of which are parallel to the load P, and the peeling stress in the adhesion surface, which is perpendicular, to the load P. These stresses distribute unevenly and the maxmium values all appear at the corner of kerfs. the stress concentration coefficients are mainly affected by the thickness ratio among the thickness structure factors and the effect of the face veneers, thickness on the stress concentration coefficients may be ignored in practice.Three kinds of 3-ply panels were made of Ash, Basswood and Lauan in the laboratory. The results of the tensile—shear strength test showed that the thickness ratio has, considerable influence on the tensile—shear strength. The reation between them could described with a quadratic equation which varied with species of veneers and from which the thickness coefficient equation and the thickness coefficients were made. The thickness coefficient must be of consideration with the consisting species of plywood:.  
          
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        发布时间：2021-03-12
      • Shi Jianping Wang Peiyuan
        Issue 3, Pages: 20-26(1989) DOI: 10.19455/j.mcgy.1989.03.005
        摘要：Rheological parameters of Mongolian Oak in compression perpendicular to grain was determined by the method of Separating the rheological parame ters. The results indicated: the linear relationship between elastic deformation and constant compression stress existed in wide stress range; the instantaneous plastic deformation in different sections was separately dependent on the stress linearly; the behavior of retarded elasticity and plasticity depending on time was mainly experssed in terms of logarithmic function; the behavior of viscoelasticity consisting of elasticity and retarded elasticity was closely corresponding with linear viscoelasticity. The results were almost the same as the results obtained from Poplar. Therefore, the differences on rheological properties between Poplar and Mongolian Oak existed in quantitative aspect only. The ratio of the rheglogical parameters between Poplar and Mongolian Oak respectively is as follows: 1) 2.4—3.4: 1 for elastic compliance; 2) 1.8—2.7: 1 for retarded elasticity. The ratio of the critical stress between Poplar and Mong0Iian Oak in compression perpendicular to grain was 1: 2.  
          
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        发布时间：2021-03-12
      • Issue 3, Pages: 26-27(1989)
        摘要：<正> 根据大力发展木材综合利用的国家产业政策,我国人造板工业将进一步发展,人造板产量将由1987年247.66万立方米,提高到2000年500万立方米。作为人造板工业配套的胶粘剂及表面加工工业亦应同步加快发展。通过会议讨论,并经专家论证,现就发展中若干重点问题提出如下建议: 一、有计划、有步骤地建立稳定可靠的化工原料供应渠道人造板胶粘剂及表面加工所需化工原料紧缺,  
          
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        发布时间：2021-03-12
      • Issue 3, Pages: 28-30(1989) DOI: 10.19455/j.mcgy.1989.03.006
        摘要：<正> 木材干燥不仅是保证木制品质量的关键,也是木材合理利用和节约木材的重要措施。建国以来,设计并建造了一大批木材干燥窑,培养了大量的木材干燥技术专业人员,有关教学、科研、设计工作也有很大发展,近几年来干燥设备制造业也已开始发展,目前已初步形成了一个以窑干为主的木材干燥生产体系。但是,由于我们原有的基础十分薄弱,并由于干燥在木材加工生产中是一项中间工序,干燥技术比较复杂,需要设备和投资,因此,  
          
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        发布时间：2021-03-12
      • Issue 3, Pages: 31-33(1989) DOI: 10.19455/j.mcgy.1989.03.007
        摘要：<正> 前言传统的人造板(本文专指刨花板或中密度纤维板)生产需施加一定量的合成树脂胶将刨花或纤维材料粘结成板。对于室内用的人造板产品主要添加脲醛树脂胶,而对室外用或结构用的人造板产品则以添加酚醛树脂胶为主。由于人造板生产对胶料的依赖性,使人造板生产的发展受到化工原料供应和价格的制约,尤其自七十年代初世界“石油危机”以来,胶料的供应和价格一直是世界各国人造板生  
          
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        发布时间：2021-03-12
      • Issue 3, Pages: 34-39(1989) DOI: 10.19455/j.mcgy.1989.03.008
        摘要：<正> 干法成型的人造板,如刨花板、华夫板、干法纤维板等,其生产过程中的削片、刨片、热磨、筛选、干燥、施胶、成型、热压等各道工序都牵涉到原材料、劳力、生产速度和最终产品。要使生产线能连续不断地运行,在最小的原材料和能源消耗下,生产出尽可能多的满足市场需要的产品,并获得利润,必须把整个生产线的各道工序按工艺要求衔接好。各工序之间不仅在顺序上要遵循一定的逻辑,  
          
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        发布时间：2021-03-12
      • Issue 3, Pages: 39-42(1989) DOI: 10.19455/j.mcgy.1989.03.009
        摘要：<正> 我国大面积种植橡胶树(Hevea brasiliensis)始于五十年代初,至1979年已有胶园578万亩。1974年冬季海南岛遭受大台风侵袭,东部几个农场,大片胶林被吹倒、折断,损失颇大。这时起提出了胶园更新和橡胶木利用问题,琼海县东泰农场率先进行了这方面试验研究。我国橡胶木防腐和利用研究,大体上经过了三个阶段:(1) 起步阶段(1975—1980),主要研究了橡胶木材的物理力学性质、菌、虫害发生  
          
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      • Issue 3, Pages: 43-49(1989) DOI: 10.19455/j.mcgy.1989.03.010
        摘要：本文仅简要介绍了龙脑香亚科木材的商品材名称、木材性质及适宜的用途。  
          
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      • Issue 3, Pages: 49(1989) DOI: 10.19455/j.mcgy.1989.03.011
        摘要：<正> 当采用脲醛树脂作胶粘剂,树脂的甲醛与尿素摩尔比(F/U)为1.27～1.01,表芯层平均树脂施加量分别为11%及8%时,刨花板的性能有如下变化:(1) 板的抗弯强度约降低10%;(2) 板的平面抗拉强度约降低30%;(3) 24小时吸水厚度膨胀率增加19%;(4) 24小时吸水率增加30.6;(5) 穿孔法测得甲醛释放量降低70%;(6) 平均释放量降低77%;(7) 板的芯层施胶量从7%增至9%时,板的内结合强度平均增加27.5%;(8)  
          
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      • Issue 3, Pages: 50-52(1989) DOI: 10.19455/j.mcgy.1989.03.012
        摘要：<正> 纤维板防水性能是一项重要技术指标,它是由生产过程中施加防水剂来保证的。用石蜡作为防水剂的施加方式有施加石蜡乳化液和直施石蜡两种。后者,工艺设备简单,不需乳化剂,成本低,防水效果相当。所以越来越多的纤维板厂改用直施石蜡,特别是采用干法生产的厂家。但直施石蜡系统自身存在的问题引起了施蜡工艺的不稳定。如直施石蜡的流量测试尚无较好的手段,又不能及时发现系统故障,等取样试验后发现时已造成了批量成品因  
          
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      • Issue 3, Pages: 52-53(1989) DOI: 10.19455/j.mcgy.1989.03.013
        摘要：<正> 胶合板虽早已被广泛地用于建筑、家具、造船、车辆、军工及其它许多工业部门。但由于其易燃,因此限制了它的使用范围。例如,船舶、火车车厢、飞机内部使用的胶合板,都有特定的阻燃要求。高层建筑主要承重构件,一般都要求达到一、二级耐火等级,同时对内部装修材料和家具也提出了相应的防火要求,因此研究阻燃型胶合板是社会主义四化建设发展的需要。阻燃型胶合板是在生产过程中同时进行阻燃处  
          
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