Suitability of acetylated woods for clarinet reed

The density (), dynamic Young's modulus (E), loss tangent (tan_L) in the longitudinal (L) direction, and the dynamic shear modulus (G), loss tangent (tan_S) in the LT or LR (T, tangential; R, radial) plane of woods and cane (Arundo donax L.) in air-dried and wet conditions were measured. The acoustic converting efficiency (ACE), expressed by E/³/tan_L, and the factors of anisotropy, expressed byE/G and tan_S/tan_L, of woods were compared with those of the canes. Low-density coniferous woods had higher ACE values and were of a more anisotropic nature than the cane. These woods seemed appropriate for clarinet reed owing to their homogeneous cellular structure. The stability in vibrational properties and the anticreep properties of the woods were enhanced by the acetylation treatment. Professional clarinet players suggested that acetylated Glehn's spruce and sitka spruce were suitable for clarinet reeds.Part of this report was presented at the 48th annual meeting of the Japan Wood Research Society at Shizuoka, April 1998     

Values placed on forest property benefits by Swedish NIPF owners: Differences between members in forest owner associations and non-members

A forest property represents benefits to the owner, the nature of which varies between resident and non-resident owners. Forest owners’ associations can be considered as an arrangement to increase the benefit from forest ownership by helping the forest owner to increase profitability. Thus, it can be assumed that associated forest owners value forest property benefits differently to non-associated owners. This study examines differences between members and non-members, and residents and non-residents, with respect to how they value the various forest property benefits. Responses from a landholder survey reveal differences concerning forestry income, maintaining contact with native locality, and keeping up a tradition in forestry. It is concluded that a challenge for the associations is to develop the organisation in accordance with the forest owners’ dissimilar property interests.     

森林旅游资源产权划分界定探析

本文通过物权与产权权利构成的对比分析,结合国有森林旅游资源产权的基本要素,提出森林旅游资源产权分割界定的初步构想,以求在明晰产权的基础上实现对森林旅游资源的有效保护和可持续利用。     

漂白紫胶贮存性质的研究(第三报)——紫胶树脂卤化及脱卤反应产物结构的研究

为了证实紫胶漂白过程中生成的不稳定结合氯和稳定结合氯在树脂分子上的位置,用壳脑酸和壳脑酸二甲酯与溴反应模拟了紫胶树脂与游离氯之间的反应。两者的溴加成产物分别为α,β-二溴壳脑酸和α,β-二溴壳脑酸二甲酯,后者的脱溴产物为β-溴壳脑酸二甲酯.用各种波谱确定了上述3个化合物的结构.实验展示了在漂白过程中游离氯加成在紫胶树脂的萜烯酸双键上生成α,β二氯衍生物,脱氯时α位结合氯和β碳原子上的一个氢原子作为氯化氢脱落而恢复双键,留下β位上稳定的结合氯.     

大孔树脂对竹叶黄酮的吸附分离特性研究

选择6种大孔吸附树脂．比较其对竹叶黄酮的吸附性能及吸附动力学过程，筛选较优的竹叶黄酮吸附剂。研究的结果表明,AB-8树脂较宜于竹叶黄酮的提纯．经AB-8树脂吸附分离后，提取物中黄酮含量提高一倍以上。AB-8树脂是一种性能优良的吸附剂。     

木材干燥设备的控制工程基础

应用控制论思想，以木材干燥设备为系统、以供给系统的条件为输入、系统的环境指标为输出，可以确定具有可比性的干燥设备的性能指标。从工程控制理论角度，分析了木材干燥设备的保温性、密封性和排湿能力。     

松桃县林农股份合作制营林案例

为解决林地权属关系造成的森林管护矛盾,特别是森林被无情偷砍盗伐,民族社区结合市场运作规律,结合传统乡土知识中的村规民约,让社区充分参与林地管理,采用林农股份合作制,将企业、村寨领袖、村民有机组织起来,有效地管护森林.     

实际尺寸乐器音板用云杉属木材的声学振动特性

以生产中使用的实际尺寸乐器音板用云杉属木材为研究对象,应用基于打击音的快速傅里叶变换分析的振动方法测定远东红皮云杉、长白鱼鳞云杉、西藏林芝云杉、美国西加云杉声学振动特性.采用综合坐标法与综合评分法对不同树种的长度L≤1 400 mm样本空间、L＞1 400 mm样本空间及不同树种分别组成样本空间进行综合振动性能分析,得出此次试验样本的综合振动性能优劣顺序基本为:西藏林芝云杉＞长白鱼鳞云杉＞远东红皮云杉＞美国西加云杉,而且这2种综合分析方法的结果具有显著相关性.结果表明:可应用本研究方法评价乐器音板用木材的综合振动性能.     

不同树龄日本落叶松的化学组成与制浆特性

对不同树龄日本落叶松的化学组成和硫酸盐法制浆特性进行研究与比较.结果表明:随着树龄的增大,原料中碳水化合物含量逐渐降低;冷水抽出物、热水抽出物和1%NaOH抽出物含量增加.碳水化合物组成中,随树龄增大,葡萄糖和木糖含量降低,半乳糖含量增加.通过对日本落叶松硫酸盐法制浆工艺参数的优化研究,确定最佳蒸煮条件为:用碱量(Na2O计)21%、硫化度25%、液比1:4、最高温度170℃、保温时间2.5 h.随着树龄的增大,蒸煮耗碱量增加,纸浆硬度增高.树龄较小的12年生日本落叶松纸浆的物理强度性能较好.综合对不同树龄日本落叶松化学组成和硫酸盐法制浆特性研究结果认为:12年生日本落叶松的硫酸盐法制浆性能优于树龄较大的日本落叶松,23年生日本落叶松的制浆性能相对较差.     

石竹材材质变异规律的研究

通过对不同年龄、不同胸径、竹竿不同部位石竹材基本密度和力学性质的测定和分析 ,结果表明 :年龄、胸径、竹竿部位对石竹材基本密度和力学性质的影响均极显著 ,且年龄对其影响大于胸径和竹竿部位 :石竹材基本密度与力学性质表现为 :上部 >中部 >下部 ,随胸径的增加而减小 ,随年龄的增大而增大 ,5年生开始呈下降趋势 ,石竹材作为结构用材的适宜采伐年龄为 4年。