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为了合理开发利用紫椴小径材,对其材性进行了研究,进而解决干燥工艺,提高干燥质量。通过研究小径材的构造和物理力学性能,并和成材作比较,研制高温干燥基准,提高紫椴小径材的干燥合格率。一、试材、试验设备及方法试材采自黑龙江省尚志县东北林业大学帽儿山林场,条件见表1。试验设备利用自行研制的间歇式电热真空干燥机,工艺试验共进行三次,每次均对试材进行质量统计,测试试材缺陷。选取5块试验板,3块含水率检验板,包括心材板、边材板、应力检验板各1块。检验板和试验板端头用铝箔纸封涂,检验板每4h称重一次。 相似文献
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山杨小径木超微结构及其与干燥皱缩的关系 总被引:1,自引:0,他引:1
前言山杨(Populus Dividiana Dode)小径木是黑龙江省尚志具帽儿山次生林区主要的间伐树种之一。该树种在干燥时易产生皱缩等缺陷,我们设想与其结构有关,故利用扫描电镜观察其超微结构,以期洞悉其中的奥秘。 W.R.Perng研究颤杨(Populus tremuloides)解剖构造与液体传导的关系,在电镜下观察时,指出颤杨心材中存在侵填体,这些侵填体使导管闭塞,因而液体流动困难。他又对此木材进行聚合物渗透,而心材导管中几乎无聚合物沉积,说明心材导管全部被侵填体堵塞,聚合物难以在心材沉积。 相似文献
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云南铁杉干燥过程中变色的控制 总被引:6,自引:0,他引:6
云南铁杉在干燥过程中的变色问题是困扰许多木业企业的一个技术难题。笔者通过近几年的研究和实践 ,从其木材组分入手 ,分析了在干燥过程中云南铁杉变色的原因 ,制定了减轻变色程度的干燥工艺措施 ,使铁杉干燥过程中的变色率降至 10 %以内 ,其质量达到国标规定相应的技术指标 相似文献
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阔叶树小径材热压干燥工艺的研究 总被引:2,自引:0,他引:2
通过对荷木和米槠两种华南地区常用阔叶树小径材薄板材热压干燥工艺的研究,探讨热压干燥工艺参数对小径材板材干燥质量(包括密度,厚度压缩率,尺寸稳定性及部分力学性能)的影响,试验结果表明,热压干燥工艺可以大大改善小径材的物理力学性能。 相似文献
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Kazumasa Yoshida Mitsuru Nishiguchi Shojiro Hishiyama Atsushi Kato Koetsu Takahashi 《Journal of Wood Science》2006,52(4):372-375
Sugi (Cryptomeria japonica D. Don) produces secondary metabolite norlignans in xylem. Several norlignans are involved in the coloration of heartwood
and defense of sapwood against microbial invasion. Their biosynthetic process should be well understood so that their properties
can be exploited to improve the quality and utility of C. japonica wood. Unfortunately, information on the norlignan biosynthesis is limited because norlignans are mainly synthesized in a
particular season in the transition zone (TZ) along with the heartwood formation, and is difficult to study. Although the
generation of two norlignans of C. japonica, agatharesinol and (E)-hinokiresinol, has been reported, systems for producing other norlignans are not yet known. To establish a novel norlignan
generating system, we examined the changes occurring in norlignans in a TZ during the process of drying a C. japonica log. On the day of felling, the TZ contained agatharesinol and (E)-hinokiresinol, which increased until they reached a maximum on day 40 after felling. Sequirin-C appeared on day 40 and increased
to day 70. The generation of sequirin-C in the TZ can be used to investigate the biosynthetic process of heartwood norlignans.
This study describes for the first time the changes that occur in the composition of norlignan during the drying of the TZ. 相似文献
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Effects of stratification, desiccation, radicle pruning, and season of sowing on Quercus vulcanica germination and growth were studied to identify optimum nursery procedures for artificial regeneration of this species. Following stratification (0, 2, 4 and 8 weeks), acorns were germinated, and acorn moisture content and germination performance were also determined at various times during desiccation. In early December unsprouted acorns were planted in containers, and in early April sprouted acorns, which had been stored in polyethylene bags at 4 °C, with radicles left intact or with radicles pruned back to 1.0 cm were planted in containers.Stratification for 2 and 4 weeks did not increase germination percentage but significantly increased germination rate. Germination percentage of the seeds dropped when the moisture content of the seeds was reduced by desiccation, and the critical minimum moisture content of the recalcitrant Q. vulcanica acorns was found to be 11–16%. Spring sowing of sprouted acorns altered the morphology the containerized seedlings and caused the formation of significantly more main roots, but resulted in significantly less shoot height and shoot dry weight. Spring-sown sprouted acorns had also a significant advantage over the fall-sown unsprouted acorns in seedling survival, and thus nursery personnel should not be concerned if acorns sprout before sowing. 相似文献
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