Quantitative dynamics on stimulating regeneration and sowing seedlings of Larix gmelinii in Daxing''''an Mountains

Introduction4LarixgmeliniiisoneofmajortimberspeciesinthenortheastDaxing'anMountainsinChina.Itplaysanimportantroleinprovidinglumber,maintainingthenaturalenvironmentinthisregionandadjustingecologicalequilibrium.Alargenumberofburnedareasandcut-overareasneedtoregenerateeveryyear.Larixgmeliniihasgreatnaturalregenerationcapabilityandenoughseedsources,andalmostmeetsabumperharvestyeareverythreeyears(Xuetal.1992;Shan1990;Xuetal.1993).Someburnedandloggedareaswouldberapidlyrestoredthroughafewofassista…     

落叶松播种苗使用钼酸铵根外追肥试验报告

通过对落叶松播种苗根外追施钼酸铵液，促进苗高，地径生长，较明显地提高了苗木整体质量，对苗木木质化和提高苗木对不良环境的抵抗力有着积极的促进作用。     

落叶松KP浆碱抽提段强化漂白研究

重点研究了落叶松KP浆CEH三段漂白碱抽提段用H2O2强化的工艺，并对添加螯合剂EDTA的效果进行了研究。     

胶合板用脲醛树脂黏度的研究

黏度是脲醛树脂性能指标的重要参数之一，黏度的控制对脲醛树脂的使用具有直接影响。从胶合板用脲醛树脂的特性出发，以终摩尔比为1．05的配方进行树脂合成，通过对脲醛树脂终点黏度和使用过程中的黏度进行研究，得到了适合胶合板的终点黏度和脲醛树脂的合理使用黏度。     

落叶松刨切薄木及其深加工工艺研究

对长白落叶松刨切用材的加工工艺进行了初步研究，结果表明：长白落叶松是一种比较理想的刨切用材，蒸煮工艺虽能较好地浸渍出树脂和软化活节，但对落叶松的死节处理尚属难题．采用此薄木贴面的刨花板，经检测各项性能指标均达到ＧＢ／Ｔ１５１０４—９４要求，用其制造的家具各项性能均达到ＧＢ４８９３—８５、ＧＢ３３２４—８２、ＧＢ１０３５７—８９要求．     

杂种二代落叶松增产能力的研究

利用杂种一代自由授粉的种子造林，所产生的杂种二代具有明显的增产能力。７年生的落叶松高生长比对照平均增加３９．６％，其保存率也普遍高于对照。杂种二代与杂种一代一样具有较强的抗寒能力和适应性。充分利用杂种一代，可节省大量的人力、物力，促进营林生产的发展。     

杨木胶合板模板工艺研究

采用正交试验方法对杨木胶合板模板生产工艺进行研究，探讨了表面处理方法、涂胶量、热压压力、热压时间等工艺参数对产品性能的影响，提出了较佳的工艺参数。试制结果表明，采用文中提供的工艺参数，可制得符合要求的胶合板模板。     

THE QUICK DETERMINATION METHOD OF RESIN CONTENT IN LARCH WOOD

The resin content in larch wood is usually determined by the traditionalBenzene-Alcohol Extract Method(BAEM).In order to meet the requirement of production prac-tice,the authors present two simple quick determination methods,IR lamp method and hydrogenperoxide solution method.Compared with the results of traditional method,the results of newmethods are nearly the same as former,therefore,both two methods can reflect the change condi-tion of resin content in wood.     

电磁屏蔽功能胶合板初探

为了赋予木基复合材料电磁屏蔽功能,在脲醛树脂胶中加入碳、石墨等导电单元,制备3层结构的杨木胶合板,研究不同导电单元对胶合板电磁屏蔽效能的影响.结果表明:导电单元的粒度越小,胶合板的电磁屏蔽效能越好,最大可达22 dB,但相关机理和量化关系还有待于深入研究.     

The effect of compression and incision on wood veneer and plywood physical and mechanical properties

ABSTRACT

Drying takes the largest share of energy in plywood production, and varying moisture content of veneers necessitates re-drying that often leads to over-dry veneers with deactivated surfaces, which may promote imperfect bonding. In order to decrease the drying time, reduce the need for re-drying of veneers, and improve the quality of plywood, birch and spruce veneers were subjected to pre-treatment by cold compression, incision, or a combination of the two. The effects of pre-treatment on the veneer and plywood quality were assessed by standard tests. Compression had a beneficial effect on water removal of the wettest veneers (spruce sapwood (SW) and birch), but some thickness reduction was observed in the veneers as well as the finished birch plywood. Compression led to thickness reduction of spruce veneers, but had no effect on SW plywood thickness likely due to higher viscoelasticity. Both compression and the combination of incising and compression levelled the moisture variation within the compressed stacks. Incision improved the modulus of elasticity of birch plywood, shear strength of SW plywood, and both bending and shear strengths of heartwood plywood. Higher surface pressure decreased the drying time of spruce SW in both plain compression and combined incision and compression pre-treatment.