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61.
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杉木间伐小径材材性试验研究 总被引:7,自引:0,他引:7
杉木间伐小径材材性试验结果与成材杉木比较:密度小,晚材率较低,生长较快,吸水性较强;材质为未成熟幼林材种,物理性质较差,力学强度有所降低,作为建筑结构用材时,在设计与施工中必须注意到其强度的降低,采取必要的措施。杉木间伐小径材纤维长度与成材相似,纤维宽度略宽、纤维长宽比值略小,但尚为良好的纤维原料。 相似文献
65.
In production industry ofAuricularia auricular, the varieties quality is most important impact factor on output. For evaluating the early quality of the edible fungus,
9 varieties ofAuricularia auricular (Au9, CF09, CF05, 29, 916, chang10, chang7, Au.Japanese and 8808) were cultured on the medium consists of potato dextrose
agar (PDA) and sawdust to test their mycelium growth rate, endurance to high temperature, resistance to mildew, assimilation
of nutriment, and resistance to drought. The result showed that the mycelium of Chang 10, CF09, 29 and Au.Japanese varieties
had the eminent characteristics such as short lifespan, stronger assimilation of nutriment, and endurance to high temperature
and steady growth. These four varieties are determined as superiority varieties ofAuricularia auricular in accordance with the research results.
Foundation item: The research was supported by Science Fund of Northeast Forestry University (2004).
Biography: Li Ling (1964-), female, Engineer in Northeast Forestry University, Harbin 150040, P. R. China.
Responsible editor: Zhu Hong 相似文献
66.
After investigating and studying the vegetation, we have established that Makehe Forest, in Sanjiangyuan Nature Reserve, Qinghai
Province, is host to a total of 364 different species, representing 173 “genera” in 55 different vegetative families. We propose
five quantifiable indices for evaluating the level of threat to these plants: 1) the distribution frequency of the “line transect”;
2) the distribution frequency of sample plots; 3) the distribution density inside sample plots; 4) the existing abundance
in the forest region; and 5) plant fidelity. The results show that there are two endangered species, six vulnerable species,
12 nearly threatened species and 344 safe species. The study tried to evaluate the urgency for conserving these plants, according
to coefficients of closeness to disappearance, of genetic loss and of usefulness. Results also showed that the number of species
of primary concern is two; of secondary concern, nine; of the third level, 23; and of least concern, 330 species.
__________
Translated from Journal of Beijing Forestry University, 2006, 28(3): 20–25 [译自: 北京林业大学学报] 相似文献
67.
The authors visited some deer farms in Northeastern China in 1991 and 1993. The seven subspecies of Asian Wapiti (Cervus elaphus) were detected by observing the animal’s appearance and analyzing the video information. The status of taxonomy research
in China was also discussed. 相似文献
68.
Gao Zhongxin Gao Erhu ZouHongfci JinKun SuJinbaoNortheast Foresty UniversityJiang ZhigongAlbeta University Canada 《林业研究》1993,4(1):64-68
Heilongjing(China)and Alberta(Canada)provinces are situated at the same lati-tude,with similar nature conditions.Mammals in Alberta account for 87 species and in Heilongj-ing,97 spesics,among which a number of orders,families and species are in common.Continentsof Eurisia and North America histoi cally were connected and separated for several times,sothere are a number of animal forms in common,among them the similarity of herbivores is rath-er high.The similarity index of cervidae is 0.54.Other orders with comparatively similarcompiosition are Insevtivora,Chiroptera and Lagomorpha.In two orders,there are no commonspecies.In these two regions,duc to historical reasons,a number of specific genera and specieswere formed. 相似文献
69.
图像分割技术在木材表面缺陷识别中的应用 总被引:3,自引:3,他引:3
阐述了图像分割技术在图像处理及分析中重要意义,以及主要的图像分割技术。以木材表面缺陷为主要研究对象,利用微分算子边缘检测、最优迭代阈值分割及形态学方法针对具有代表性缺陷死节和虫眼进行分割处理。 相似文献
70.