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Search Results: 1 - 10 of 74193 matches for " 蔡家斌 "
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热压干燥工艺对速生杉木板材尺寸稳定性的影响

南京林业大学学报(自然科学版) , 1997, DOI: 10.3969/j.jssn.1000-2006.1997.04.023
Abstract: <正>取速生杉木(cunnighamialanceolata)生材制成试件后,在几种工艺条件下热压。测定了试片在全干状态下尺寸的弹性恢复率、吸湿膨胀率、平衡含水率等物理性质的变化情况。结果表明:(1)随着压缩率的增加,木材压缩弹性恢复率减少,当压缩率大于45%时,试件基本定形;(2)热压干燥还可以改变木材的吸湿膨胀特性,降低木材的吸湿能力,有利于提高木材的尺寸稳定性。
国家重点学科――木材加工与人造板工艺

南京林业大学学报(自然科学版) , 1993, DOI: 10.3969/j.jssn.1000-2006.1993.04.020
Abstract: <正>木材加工与人造板工艺学科主要研究木材加工与人造板生产的新工艺、新技术,以期高效合理利用木材。主要研究方向为:人造板、木材干燥、制材、木制品工艺、家具及室内设计和木材加工自动化。本学科自1987年被国家教委批准为重点学科以来,共完成并通过部省级鉴定的科研项目
热处理辐射松吸湿解吸等温线的测定与分析
姚晴,
- , 2018, DOI: 10.13360/j.Issn.2096-1359.2018.03.006
Abstract: 为了筛选出适合新西兰辐射松的等温吸湿解吸模型,以新西兰辐射松板材为研究对象,经热处理温度为160,170,180,190,200和210℃,处理时间为2.0 h的热处理后,通过动态水分吸附仪研究热处理材的平衡含水率与热处理温度的关系,同时选用PEK模型及6种吸湿解吸等温线模型对平衡含水率数据进行非线性拟合并对其拟合效果进行评价,以确定最佳拟合模型及其参数。结果表明:在相同湿度条件下,热处理材平衡含水率最高为15.102%,低于对照材16.323%,相同处理温度的木材在相同湿度下,吸湿平衡含水率小于解吸平衡含水率; 不同处理温度的木材吸湿解吸平衡含水率随热处理温度的升高而逐渐降低。PEK模型可以预测木材在吸湿和解吸过程中的含水率,其拟合度R2在0.99以上。在6种吸湿解吸等温线模型中,GAB模型为最优拟合模型,可以预测不同环境湿度下木材的平衡含水率,其拟合度R2在0.99以上。
As an effective modification method for wood, heat treatment improves the dimensional stability of timber by lowering its hygroscopicity. The purpose of this study was to analyzed the effect of heat treatment temperature on the equilibrium moisture content(EMC)of heat-treated wood by using the dynamic vapor sorption(DVS)apparatus, and the EMCs obtained from DVS measurements were fitted by the parallel exponential kinetics(PEK)model, BET(Brunauer-Emmett-Teller), GAB(Guggenheim-Anderson-deBoer), Halsey, Henderson, Oswin, and Smith sorption isotherms models, so as to determine the best fitting model and its parameters. Radiata pine(Pinus radiata D.Don)timber was used as a tested material and heat-treated with steam at 160℃, 170℃, 180℃, 190℃, 200℃ and 210℃, respectively, for 2.0 h. The EMC of heat-treated wood was studied by using the dynamic vapor sorption(DVS)apparatus. Then the EMC was analyzed by parallel exponential kinetics(PEK)model and six typical sorption isotherm models. The resulte showed that the relative humidity(RH), the adsorption and desorption EMCs of the heat-treated wood(15.102%)were lower than those of the control sample(16.323%). At the same RH and heat treatment temperature, the EMC was lower in adsorption than that in desorption process, and the moisture content in both adsorption and desorption processes increased with the increase of heat treatment temperature and relative humidity. Under 25℃ and 70% RH, the EMC of treated wood that underwent adsorption were 6.302%-10.188%, while that of the control sample was 11.433%. The EMC of wood decreased by about 44.88% after the heat treatment. The treated wood that underwent desorption attained the EMC between 8.068% and 12.800%, while the control sample was 13.772%. The EMC of heat-treated wood decreased by 41.42% compared with that of the control sample. The results of the PEK model showed an excellent fit to the sorption-desorption curve of the heat-treated wood(R2>0.99). Among the 6 typical sorption isotherm models, the GAB model showed a good fit to the experimental EMC of wood(R2 > 0.99). The heat treatment with steam improved the dimensional stability of Radiata pine. The increase
速生杉木薄板热压干燥的试验研究
,钱世江
南京林业大学学报(自然科学版) , 1997, DOI: 10.3969/j.jssn.1000-2006.1997.03.007
Abstract: <正>研究了用热压干燥法干燥杉木(cunninghamialanceolata)速生材地板用材试件截面的温度分布、干燥速度、压缩率与密度等基本规律及干燥工艺参数对杉木干燥质量、静曲强度、表面硬度和尺寸稳定性的影响。研究结果表明,热压干燥可大大缩短干燥时间,提高杉木地板的力学强度;干燥过程中采用呼吸工艺和缓慢卸压的方法,可避免产生内裂,保证地板的干燥质量。
金银花中药材干燥技术研究
陈昌民,杜国兴,
南京林业大学学报(自然科学版) , 1997, DOI: 10.3969/j.jssn.1000-2006.1997.03.010
Abstract: <正>研究了中药材金银花的干燥特性,研制了干燥装置并制定了干燥工艺。结果表明,干燥工艺是可行的,干燥后的金银花含水率均匀;与农户现用的烘干技术相比,干燥周期缩短50%,干燥成本降低79%,干燥后的质量达一级品的质量要求。
利用核磁共振测定木材润胀细胞壁的水分含量与孔径分布
,,,金菊婉,庄寿增
南京林业大学学报(自然科学版) , 2017, DOI: 10.3969/j.issn.1000-2006.2017.02.022
Abstract: 【目的】利用核磁共振冻融分析技术测定杉木与杨木两种速生材细胞壁润胀状态吸着水含量与孔隙分布情况,为改性剂粒径选择与改性效果评价提供方法。【方法】常温下获得试样内水分T2弛豫信号总量,通过核磁冻融分析系统对试样进行降温处理,检测不同冷冻温度条件试样内未冻结水分信号量; 依据Gibbs-Thomson效应确定凝固点降低与孔径的关系,并以此分析孔径分布。【结果】核磁冻融法测定杉木和杨木吸着水饱和含量约为38%,高于通过吸湿外推法估算数值,与溶剂排出法、多孔板法、离心法结果相近; 核磁冻融分析法避免了常温条件按照T2弛豫分布确定吸着水含量偏小的现象; 两种速生材试样细胞壁润胀状态孔径小于1.59 nm的孔隙占比约为75%,大于4.56 nm的孔隙占比不超过6%,与溶剂排出法、光谱标记法结果相符。【结论】核磁共振冻融分析技术可较为便捷准确地获得木材吸着水含量与细胞壁孔隙分布,其结果可用于指导改性剂粒径的选择与改性效果评价。
【Objective】 The purpose of this study was to determine the bound water content and pore size diameter distribution in the swollen cell walls of two fast-growing trees(Cunninghamia lanceolata(Chinese fir)and poplar)using nuclear magnetic resonance(NMR)cryoporometry. The results should be valuable in the selection of particle size for wood modification. 【Method】The T2 signal amplification of specimens at normal temperature and different frozen temperatures was compared to avoid the phenomenon that bound water content is lower than the theoretical value determined by T2 relaxation distributions at normal temperature. The maximum moisture content and pore size diameter distributions of the swollen cell wall were determined from the total signals of samples according to the Gibbs-Thomson equation, and inversion calculations were omitted. 【Results】 The saturated bound water content of Chinese fir and poplar was approximately 38%, which was clearly higher than the fiber saturation point(approximately 30%)measured by the extrapolation method, but was in accordance with solute exclusion, porous plate and centrifugal methods. The proportion of pore diameters smaller than 1.59 nm was approximately 75%, and the proportion of pore diameters larger than 4.56 nm was below 6%; this result was also in accordance with solute exclusion and spectral methods. 【Conclusion】 The bound water content and pore size diameter distributions of the cell wall could be conveniently and accurately determined by NMR cryoporometry, which could be used in the selection of modification agents and evaluation of modification effects
热处理对木材吸湿特性及尺寸稳定性的影响
,,顾炼百,
南京林业大学学报(自然科学版) , 2015, DOI: 10.3969/j.issn.1000-2006.2015.02.025
Abstract: 分别在常压蒸汽与0.45 MPa加压蒸汽条件下,对樟子松和柞木进行热处理,比较了热处理材和未处理材的水分吸湿性及尺寸稳定性差异。结果表明:两种试材经过热处理后不仅吸湿量明显降低,在高湿条件下的吸湿特性也发生了显著变化,当环境相对湿度从69%增至94%时,热处理材的平衡含水率变化率仅为对照材的1/3,细胞壁微观构造在高温条件下的变化可能是造成这一现象的主要原因; 吸湿性的降低使热处理材的尺寸稳定性获得了大幅度提高,樟子松试材加压蒸汽热处理后径、弦向湿胀率分别下降了34%和47%,柞木则分别降低了46%和51%; 热处理材的弦向抗湿涨系数普遍高于径向抗湿涨系数,表明木材径、弦向的湿胀差异在热处理后也有所缩减; 加压蒸汽热处理比常压蒸汽热处理的改性效果更为显著。
Heat treatment of Pinus sylvestris and Quercus mongolica boards were carried out in atmospheric stream or 0.45 MPa pressurized steam. Hygroscopicity and dimensional stability of the treated wood were compared with the control. The results showed that heat treatments not only lowered the equilibrium moisture contents(EMC)of the wood, but also altered the pattern of its moisture adsorption in high humidity environment. When the environmental relative humidity increased from 69% to 94%, the EMC change rates of the heat treated samples were just one third of those of the control samples. This might be attributed to the reconstruction of wood cell wall during the heat treatments. Dimensional stability of heat treated samples was significantly improved as a result. The radial and tangential swelling of pressurized-steam treated Pinus sylvestris samples decreased by 34% and 47% compared to those of the control ones. For Quercus mongolica samples, the corresponding values were 46% and 51%. Most tangential anti-swelling efficiency(ASE)values of the heat treated samples were higher than their radial ASE values. That means swelling difference between radial direction and tangential direction was also reduced after heat treatments. It was also showed that pressurized steam induces more pronounced property modification than atmospheric steam
冬虫夏草菌丝体水提醇沉物体外抗肿瘤活性研究
,,张璇,,,,傅晓波,,沈星灿
药物评价研究 , 2014, DOI: 10.7501/j.issn.1674-6376.2014.2.003
Abstract: 目的 研究冬虫夏草菌丝体水提醇沉物的体外抗肿瘤活性及其机制。方法 采用热水浸提-醇沉法得到水提物,高效液相色谱仪测定水提醇沉物中腺苷的量;采用MTT法测定其抗肿瘤活性,利用流式细胞仪结合碘化丙锭染色法检测其对细胞周期的抑制。结果 实验表明水提醇沉物能抑制人肝癌HepG2细胞株及大细胞肺癌NCI-H460细胞株的增殖,并呈浓度相关性;半数抑制浓度(IC50)值分别为(1.49±0.19)和(1.67±0.27)mg/mL。细胞周期分析表明,水提醇沉物分别阻滞HepG2及NCI-H460细胞周期于G2/M期、S期,并可诱导上述两种细胞发生凋亡。结论 冬虫夏草水提醇沉物通过阻滞HepG2及NCI-H460细胞周期循环,诱导其凋亡,从而表现出良好的增殖抑制活性。为深入研究冬虫夏草菌丝体水提醇沉物抗肿瘤的机制提供了实验证据。
云杉木材年轮方向对钢琴音板声学性能的影响
张超华,徐伟,吴智慧*,,罗建峰
南京林业大学学报(自然科学版) , 2010, DOI: 10.3969/j.jssn.1000-2006.2010.03.034
Abstract: 选择钢琴音板用木材北美云杉(piceaspp.)作为研究试材,测定了云杉木材含水率为7%时径切板的动弹性模量(e)、比动态弹性模量(e/ρ)、对数衰减率(δ)、损耗角正切(tanδ)等声学性能指标。结果表明:板厚中心线与生长轮切线之间夹角为90°的径切板,径向、弦向振动时的声学性能均优于夹角为60°的径切板;夹角为90°的径切板弦向振动时的声学性能优于径向振动时的声学性能。
稀土对杉木、杨树幼林生长的影响
马永春,罗宁,张文,徐六一,,卫兵
南京林业大学学报(自然科学版) , 2001, DOI: 10.3969/j.jssn.1000-2006.2001.04.016
Abstract: <正>对杉木[cunninghamialanceolata(lamb)hook]、杨树(populuscv.‘lux’)施用稀土后幼树的根系吸收等指标进行的观测结果表明,用不同浓度的稀土处理苗木,其单株幼树根系的总吸收面积、活跃吸收面积差异显著,根系的比表面差异不显著。杨树以500mg/kg的稀土溶液浸根时根系的吸收指标最高,杉木以800mg/kg浓度叶面喷施最高。经不同浓度稀土处理后,与对照相比,杉木、杨树在同时期所测得的高生长量、地径生长量、根系干重均有不同程度的提高
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