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1.
分光光度法测定倍子单宁酸的研究   总被引:4,自引:0,他引:4  
本文报道了用紫外和可见分光光度法测定倍子单宁酸的研究。着重论述了两种方法的测定条件和精密度,测定结果与皮粉法作了对照。 研究结果证明,两种方法都比较快速和简便,紫外分光光度法精密度较高,偏差较小,更适于倍子单宁酸的定量分析。  相似文献   

2.
EDTA二钠滴定法测定钙离子含量滴定终点的确定   总被引:5,自引:0,他引:5  
本文通过对EDTA滴定法测定钙离子含量试验原理的分析提出了正确读取在滴定终点时,所用EDTA二钙溶液溶量的方法,对工地试验现场较精确测定水泥或石灰剂量有一定的意义.  相似文献   

3.
倍花酸水解法制工业没食子酸   总被引:1,自引:1,他引:1  
  相似文献   

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5.
The concentration influence of some commercial polyethylenimines, used as retention agents, on the retention efficiency during the sheet formation is studied in this paper. The conditions of an industrial wire end have been simulated by means of a dynamic jar of exclusive design. Measurements of the zeta potential have been taken to quantify the surface charge of particles and the colloid titration ratio (quotient between the cationic demand and the anionic demand of pulp slurries) has been evaluated. Both techniques have proved convenient to monitor the retention level; therefore, they are efficient methods to control the retention level in the sheet formation. The univocal relation existing between zeta potential and the logarithm of the colloid titration ratio has been demonstrated. Finally, the variation of the level of turbulence has proved the importance of the hydrodynamics factors in the retention.  相似文献   

6.
刘珊杉  周亚菲  刘巍岩 《林业科技》2020,45(1):26-28,62
采用双螺旋挤出成型、模压成型和注塑成型3种不同成型工艺制备木纤维/聚乳酸复合材料,通过对比不同制备方法对复合材料密度、静曲强度、弯曲模量、拉伸强度和冲击韧性的影响可知:使用挤出成型方法制备的木纤维/聚乳酸复合材料的密度最大,各项物理力学性能也显著高于使用注塑法和模压成型制备的复合材料试件。  相似文献   

7.
木材综合信息数据库查询系统的研究   总被引:6,自引:0,他引:6  
程放  王艳君 《木材工业》1995,9(4):16-19
木材综合信息数据库查询系统是在收集、整理我国木材科学领域多年来研究成果和实验数据的基础上,建立起来的大型木材科学综合信息数据查询应用软件包。系统收录有木材标本、木材译名、木材用途、及木材解剖识别、木材眼微构造、木材化学、木材物理力学、木材、木材热学、木材声学及木材渗透性等信息,建立了十二个专项子数据库。  相似文献   

8.
木材(特征图象)的微机识别   总被引:4,自引:0,他引:4  
通过对“微机辅助木材识别系统WIP-89”项目的发展和增补,在木材识别方式上有新的突破,即通过木才解剖图象,微机自动识别木材,现已解决针对树材中的早材至晚材,急变和渐变;阔叶树材中的环孔材、半环孔材和散孔材。  相似文献   

9.
大力发展木材防腐,节约木材   总被引:10,自引:2,他引:10  
本文分析了我国木材防腐的现状,并着重从建筑木材防腐,人工林木腐,木材,竹材的蓝变菌和霉菌防治,以及新型防腐剂的研究与发展等四个方面探讨了在新世纪初我国木材防腐的发展方向。  相似文献   

10.
木材渗透性研究的现状与趋势   总被引:3,自引:0,他引:3  
本文在综合分析大量文献的基础上,详细介绍了国内外木材渗透性研究领域中的主要理论和常用的木材结构模型,简述了我国学者在木材渗透性应用上取得的主要成果,并提出一些今后研究的方向。  相似文献   

11.
对水青冈木材构造和利用进行了研究,结果表明:水青冈木材为半环孔材,具宽木射线,射线组织异形Ⅲ型,纤维长度和长宽比大,差异壁厚和微纤丝角小;木材不变形,材质优良,花纹美丽,为建筑、家具、地板、装饰、贴面板、造纸和纤维工业及种的鉴定提供了理论依据。  相似文献   

12.
本文论述了木材检验中造材后量材改锯中存在的问题。如原木的一断面腐朽为薪材,而另一端为优良断面的木材,如何进行量材改锯等等。并提供了木材改据参考一览表。  相似文献   

13.
分形理论在木材科学与工艺学中的应用   总被引:12,自引:1,他引:12  
费本华 《木材工业》1999,13(4):27-28
分莆是一种新兴的基础理论,将在成为木材科学研究的有效手段之一,本文阐述了分形理论的基本概念、原理和应用,着重介绍分形在木材解剖学、木材物理力学和加工过程中的应用前景。  相似文献   

14.
相思类树种木材的资源、材性与加工利用   总被引:12,自引:0,他引:12  
相思类树种生长速度快,适应性强,在我国南方广泛引种栽培。通过对其木材的解剖特征、天然耐腐性、干燥特性、制浆造纸性能以及人造板和细木工等加工性能的分析,结果显示,相思类树种木材不但是优良的纸浆材原料之一,而且多数树种木材也是生产人造板和实木家具等的较好原料。  相似文献   

15.
由于木材变色已给木材工业带来较大的经济损失,因此,有效地保护木材,提高它的利用率就变得更加重要。本文对由长喙壳和其他真菌引起的木材变色,变色机理,为害,对木材性质的影响,以及我国主要木材变色病的研究进行了概述。  相似文献   

16.

Properties of 200 poorly debarked softwood logs were studied in order to examine how different log characteristics affect drum debarking of mixed pine (Pinus sylvestris L.) and spruce [Picea abies (L.) Karst] pulpwood during the summer. The definition of a poorly debarked log and the sampling criterion was that >10 dm2 bark remained on the log surface. The average share of poorly debarked logs was 8% and the most frequent log type was breakage logs. The main species among the poorly debarked logs was spruce and the mean wood moisture content was considerably lower than for the pulpwood chips. Many logs were affected by root rot or were damaged by harvesting equipment, resulting in reduced moisture content and, consequently, in increased bark/wood shear strength. Bark from the poorly debarked logs contributed to approximately 68% of the bark content in the chips. By avoiding air-drying of pulpwood, or by sorting pulpwood prior to debarking, the bark content in chips might be substantially reduced, which would improve the purity of the pulp and decrease production costs.  相似文献   

17.
Phenylboronic acid (PBA) was tested in terms of boron leachability from treated wood. In addition, the fungal and termiticidal efficacy of PBA-impregnated sugi (Cryptomeria japonica D. Don) wood was tested against the decay fungi Coriolus versicolor (L. ex Fr.) Quel. and Tyromyces palustris (Berk. et Curt) Murr., representing white-rot and brown-rot fungi, respectively, and the Formosan subterranean termite Coptotermes formosanus Shiraki. Ion chromatography analysis of hot water extracts of treated wood before and after leaching indicated that PBA is considerably resistant to water leaching, and saturation of the treatment solution increased the fixation ratio of boron in wood, whereas boric acid could not remain in wood impregnated even with the saturated solution. Decay test results revealed the excellent bioactive performance of PBA. Wood treated with 0.34% PBA solution was found resistant to both decay fungi, even after running-water leaching for 10 days and treatment with 1.00% PBA completely inactivated the Formosan subterranean termite for the leached specimens. Weight gain levels were 0.18% w/w (0.46kg/m3) and 0.99% w/w (2.49kg/m3) for these concentration levels, respectively, after being leached by running water. Contrary to the general belief that boron is a slow-acting toxicant against termites and unable to prevent mass loss of treated wood, PBA acted rapidly, and the mass loss caused by termites was low.This study was presented in part at the 47th annual meeting of the Japan Wood Research Society, Kochi, April, 1997  相似文献   

18.
聚乳酸是一种强度较高的聚酯类材料,其良好的降解性能在保证了其环保优势的同时,也对其物理力学性能产生一定影响。本研究将木纤维/聚乳酸复合材料置于水环境中进行水解处理,然后测试复合材料的力学性能。结果显示,将复合材料放置在水中一段时间后,复合材料的弯曲性能和拉伸性能都显著下降,木纤维含量越高,材料性能下降越明显。这说明水环境使聚乳酸分子链发生了水解反应,使材料性能下降;同时,木纤维的吸水膨胀和干燥收缩也使材料界面薄弱点增加,使材料性能有所下降。  相似文献   

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20.
壳聚糖(chitosan)是从虾、蟹等甲壳动物中提取的一种天然碱性高分子多糖,壳聚糖易与过渡金属及稀土金属配位形成壳聚糖金属配位聚合物[chitosan metal complexes(CMC)],壳聚糖及壳聚糖金属配位聚合物是目前研究广泛的一类新型高分子生物材料,近年来的研究表明壳聚糖及壳聚糖金属配位聚合物在木材工业中有着广泛的应用前景,例如作为环保型木材防腐剂,促进木材防腐工业的持续发展。笔者介绍了其基本应用,重点报道其在木材染色、木材保护及用于木质材料胶合方面的应用及研究进展。  相似文献   

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