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木材液相乙酰化处理及处理材尺寸稳定性和耐腐性的研究 总被引:2,自引:0,他引:2
本文论述了马尾松、白桦和青杨三种木材的液相乙酰化条件及各种乙酰化木材的尺才稳定性和耐菌腐能力。以乙酸酐和二甲苯为处理液,反应的最佳条件是:温度120℃,时间7到11小时,乙酸酑与二甲苯配比1:1。当处理试样的增重到15%时,抗收缩率可达60%以上。增重为11.75—17.98%的不同处理试块,其耐菌腐能力可提高3—34倍。 相似文献
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From the heartwood-free stemwood of Pinus densiflora, 7 compounds inhibitory to the linear growth of Fomes annosus were isolated. These were identified as pinosylvin, pinosylvin monomethyl ether, (3-sitosterol, a cembrol-like diterpene alcohol, and three isomeric diterpene acids belonging to the abietane group, one of which is probably palustric acid. Other antifungal fractions contained complex mixtures and were not characterized. 相似文献
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Ahmed Mohareb Marie France Th��venon Edmond Wozniak Philippe G��rardin 《Wood Science and Technology》2011,45(3):407-417
In this study, the use of polyvinyl alcohol (PVA) as boron fixative agent was investigated. Two levels of PVA (2.5 and 4%) were evaluated with disodium octaborate tetrahydrate (DOT) at three concentrations (1, 2 and 4% boric acid equivalent (BAE)) using a double vacuum impregnation process on Scots pine sapwood specimens. Leaching was performed according to a laboratory leaching procedure. Boron analysis using atomic absorption spectrometer showed a significant reduction in boron leachability for the samples treated with both concentrations of PVA when compared to the stand-alone boron treatment leading to boron retentions capable of preventing wood biological degradations. Decay resistance of the leached specimens was evaluated using the brown rot fungus Poria placenta. Even if complete protection was not fully achieved, an improvement in decay resistance was observed for the samples treated with DOT in presence of PVA. This leak of efficacy was attributed to a decrease in the biological activity of the complexed boron against fungi. Durability of treated wood against termite attack, evaluated using Reticulitermes santonensis, indicated a significant enhancement for the samples treated in presence of the fixative agent compared to the pure boron treatment. 相似文献
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木材天然耐腐性室内试验标准方法的研究 总被引:1,自引:0,他引:1
采用三种培养基、两种白腐菌、两种褐腐菌对马尾松、毛白杨的天然耐腐性进行了试验。结果表明:砂子锯屑培养基法对采绒革盖菌(Corjolus versicolor)和绵腐卧孔菌(Poiraplacenta)的生长较快,对木材腐朽力,即重量损失较明显。 相似文献
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Thomas Walther S. Nami Kartal Won Joung Hwang Kenji Umemura Shuichi Kawai 《Journal of Wood Science》2007,53(6):481-486
The development of oriented fiberboards made from kenaf (Hibiscus cannabinus L.) and their suitability as a construction material has been investigated. Three different types of boards consisting of
five layers with individual orientations were prepared using a combination of low molecular weight and high molecular weight
phenol-formaldehyde (PF) resin for impregnation and adhesion purposes. Additional boards with the same structure were prepared
using high molecular weight PF resin only. The mechanical properties of the boards have been examined as well as their resistance
against fungal decay and termite attack. All kenaf fiberboards showed elevated mechanical properties compared with medium-density
fiberboard made from wood fibers, and showed increased decay and termite resistance. Differences in the decay and termite
resistance between the board types were caused by the presence of the low molecular weight PF resin for the impregnation of
the fibers. No significant difference was found for the mechanical properties. The effect of the PF resin for impregnation
was much clearer in fungal decay resistance than for termite resistance; however, fiber orientation had no effect on both
decay and termite resistance of the specimens. 相似文献
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以毛竹和重组竹为研究对象,用绵腐卧孔菌(PV)、密粘褶菌(GT)两种褐腐菌和彩绒革盖菌(CV)、变色栓菌(TV)两种白腐菌进行腐朽试验,比较分析了毛竹和重组竹腐朽前后表面视觉性质及其质量损失差异。结果发现:毛竹和重组竹颜色均发生了显著变化,主要表现为明度(L~*)降低,色度值(C)、红绿轴色品指数(a~*)和黄蓝轴色品指数(b~*)显著增大,其中绵腐卧孔菌对毛竹及重组竹的色差影响最大。重组竹(耐绵腐卧孔菌)能达到Ⅰ级强耐腐水平;毛竹(耐绵腐卧孔菌)和重组竹(耐密粘褶菌和彩绒革盖菌)达到了Ⅱ级耐腐水平;毛竹(耐密粘褶菌、彩绒革盖菌和变色栓菌)和重组竹(耐彩绒革盖菌)为Ⅲ级稍耐腐水平。整体来看,重组竹对白腐菌和褐腐菌的耐腐效果好于毛竹。绵腐卧孔菌虽然对毛竹和重组竹的降解能力最弱,但对其颜色变化的影响却最大。扫描电镜可观察到彩绒革盖菌通过毛竹导管壁上的纹孔进入薄壁细胞、伴胞等,同时通过分泌木质素酶导致其细胞壁降解。 相似文献
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A comparative study of mangrove ? oras in China and India 总被引:1,自引:0,他引:1
Species compositions in the mangrove habitats of China and India, especially on Hainan Island (China) and on the Sundarbans and the Andaman & Nicobar Islands (India), are of interest, showing several similarities and differences. The total mangrove areas of India cover about 6419 km 2 with 43 species (23 major and 20 minor species), while the mangrove areas of China cover about 150 km 2 with 26 speices (19 major and 7 minor speices). We carried out a comparison of mangrove floras in the Indian Sundarbans, Andaman & Nicobar Islands and in Hainan Island. The mangrove areas of the Indian Sundarbans comprise about 66.5% of the total Indian mangroves, presently covering an area of 4267 km 2 with 35 species from 22 genera and 16 families. There are 34 species from 17 genera and 13 families in the Andaman & Nicobar Islands. Hainan Island is considered a distribution center of mangroves; it has the largest number of mangrove species in China, i.e., 25 species from 15 genera and 12 families, accounting for about 96% of the total number of mangrove species in China. The mangroves of Hainan Island and the Andaman & Nicobar Islands belong to island types, while those of Sundarbans belong to inter-tidal deltaic types. Differences in soil type, rainfall, temperature, tidal fluctuation and other climatic features possibly cause variations in floristic composition of these regions. 相似文献
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In order to develop a fireproof wooden material, the synergic effect of fire-retardant chemicals and wood coatings was studied.
The fire performance was evaluated by cone calorimeter. Impregnation of fire retardants including polyphosphatic carbamate,
and ceramic coatings including alkoxy metal salt improved the fire performance of wooden materials. This treatment made it
possible to meet the guidelines for fire performance of noncombustible materials in Japan. In addition to the vacuum-pressure
impregnation treatment, hot-and-cold-bath impregnation treatment is an effective way to develop fire-retardant wood by impregnating
fire retardant and ceramic coating. The weatherability of the developed material was also investigated. The ceramic coating
was resistant to light and moisture.
Part of this report was presented at 54th Annual Meeting (Sapporo, August 2004) and the 55th Annual Meeting (Kyoto, March
2005) of the Japan Wood Research Society 相似文献
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The formation of insoluble metaborates in wood was investigated by impregnating the wood with borax and metallic salts, after which their properties (e.g., leachability in running water and biological resistance) were evaluated. The solubility of three metaborates in acidic solutions was also evaluated. Double-diffusion treatment was carried out to form the precipitates of metaborates in sapwood specimens of Japanese cedar (Cryptomeria japonica) at room temperature. Water-saturated wood specimens were first impregnated by a saturated borax solution and then diffuse-penetrated with Zn2+, Ca2+, or Pb2+ solution. The precipitates of the three metaborates in the wood proved to be insoluble or hardly soluble in water by the leaching test. With the decay test using a brown-rot fungus (Fomitopsis palustris) and a white-rot fungus (Trametes versicolor) and with the termite test using a virulent subterranean termite (Coptotermes formosanus), the metaborate-treated woods showed generally good decay and termite resistance with negligible mass loss of the specimens. Particularly, the lead metaborate formed in the wood provided superb biological resistance against decay and termite attacks. In addition, the precipitates of these metaborates were found to be soluble in acidic solution, suggesting a way to remove these chemicals from wood when disposing of waste materials. 相似文献
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Chen Xiquan 《林业研究》1994,5(1):23-27
According to the study on soils under the 34-year-old Larch forest and Larch-Walnut mixed forest, It was concluded that, in
mixed forest, the total content of water-stable aggregate (0.25–5mm) in the upper layers (0–30cm) of soil was significantly
higher than that in pure forest. The 2mm aggregates increased 48% in mixed forest soil compared with pure forest, and consequently,
the three-phase ratio of soil was regulated, the physical properties improved and the fertility of soil raised. Because of
the stability of total aggregate content and the importance of 2mm aggregate content in soil fertility, it’s advisable using
the two indices above to characterize the effect of mixed forest on soil improvement. 相似文献
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The antimicrobial activity of dichloromethane extracts (leaves, flowers and underground parts) and some compounds isolated from Calea platylepis were evaluated by the well diffusion method. 相似文献
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通过对山梨种子5种层积处理方法的发芽率、霉烂率、坏死率、未发芽率及种子活力指数的测定。分析了各种处理方法的优缺点,认为山梨种子进行层积处理袋贮雪藏法最佳。其次为沙贮窖藏法和袋贮吊袋法。沙贮土埋法及冰箱贮藏法不宜采用. 相似文献
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《林业研究》2020,31(5):2023-2029
The experiment was conducted to improve the decay resistance of wood by increasing the wood preservatives uptake and penetration depth by bioincising with Coriolus versicolor. The mechanical properties of bioincised Populus davidiana sapwood were measured. The changes of wood components(lignin, cellulose and hemicellulose) were analyzed by FTIR. The staining treatment using potassium permanganate was to measure the preservatives uptake and penetration depth in wood specimens. The decay resistance of bioincised specimens impregnated with IPBC and CA was assessed against C.versicolor and Gloeophyllum trabeum using bioincised P.davidiana sapwood and untreated controls. The results showed that the mechanical properties of the bioincised specimens were changed with the incubation time and mass loss. The mechanical strength was decreased after 17 days compared to that of the specimens bioincised 13 days.The bioincised specimens demonstrated the deeper penetration depth than the un-bioincised specimens. It was significant correlation(P 0.01) between penetrationdepth and incubation time. The average value of the penetration depth of the bioincised specimens was deeper than the control groups by 158.7%. By FTIR analysis, the biodegradation ability of C. versicolor to decay cellulose and hemicellulose was weaker than that of lignin. The bioincising treatment significantly increased the wood uptake of IPBC and CA, and reached the maximum uptake value at 17 and 13 days, respectively. Summarily, the bioincising pretreatment can obviously improve the wood decay resistance against C. versicolor and G. trabeum following by introducing the IPBC and CA. 相似文献
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The effect of 600 mg/kg given by oral route to rats of Ferula hermonis roots extracts (petroleum ether, ethyl acetate, methanol and water) was evaluated on sexual behaviour of male rats. Petroleum ether and ethyl acetate extracts produced a significant decrease in both the mount rate (MR) and the intromission rate (IR), significant prolongation of intromission latency (IL) was observed when these extracts were compared with both controls and sildenafil. Methanolic extract produced a significant increase in MR while no effect has been observed on IR or IL in comparison with control. The effect of water extract was not significantly different from controls for the MR and IR, but there was a significant prolongation in the IL. 相似文献