In order to investigate the influence of length and compression directions upon behaviour of parallel bamboo strand lumber(PBSL)specimens,240 axial compression tests have been performed.With three similar one differen...In order to investigate the influence of length and compression directions upon behaviour of parallel bamboo strand lumber(PBSL)specimens,240 axial compression tests have been performed.With three similar one different typical failure modes,the mechanical performance for PBSL specimens under compression parallel to grain and perpendicular to grain are different as a whole.From the point of the characteristic values,the compression strength parallel to grain is 2.1 times of the compression strength perpendicular to grain.The elastic modulus for compression parallel to grain is 3.64 times of the compression strength perpendicular to grain.While the compression ratios along two compression directions are equal to each other.The bigger Poisson ratios for one typical side surface is 3.93 times of that for another typical side surface for PBSL specimens under compression perpendicular to grain,and the bigger value is equal to that for PBSL specimens under compression parallel to grain.Length can influence the mechanical properties of the PBSL specimens.The size 50 mm×50 mm×100 mm should be good choice for the standard or code to measure the compression strength.PBSL materials have better ductility under compression parallel to grain than that under compression perpendicular to grain.Stress-strain relationship models were proposed for PBSL specimens under compression parallel to grain and perpendicular to grain,respectively.These proposed models gave a good agreement with the test results.展开更多
A comparative study was conducted on liquid penetration of the freeze-drying and air-drying sapwood and heartwood lumber of plantation Chinese fir （Cunninghamia lanceolata）. The maximum amount of dyeing solution upt...A comparative study was conducted on liquid penetration of the freeze-drying and air-drying sapwood and heartwood lumber of plantation Chinese fir （Cunninghamia lanceolata）. The maximum amount of dyeing solution uptake by the capillary rise method was used to evaluate the liquid penetration properties of the treated wood. The pit aspiration ratio was determined by semithin section method. Changes in wood microstructure were investigated using scanning electron microscopy. The results showed that compared with air drying, the freeze drying had a significant effect on liquid penetration of sapwood and heartwood of Chinese fir. The liquid penetration of sapwood is significantly higher than that of the heartwood for both drying treatments. Low pit aspiration ratio and cracks of pits membrane of some bordered pits are the main reasons for increasing liquid penetration after freeze drying treatment.展开更多
Objective： To compare the effect differences of electroacupuncture（EA） at Jiajǐ（夹脊 EX-B2） and conventional acupoints for lumbar intervertebral disc herniation（LIDH） and the factors influenced the effect duri...Objective： To compare the effect differences of electroacupuncture（EA） at Jiajǐ（夹脊 EX-B2） and conventional acupoints for lumbar intervertebral disc herniation（LIDH） and the factors influenced the effect during the way of data mining.Methods： A total of 160 patients of LIDH were randomly assigned into the EX-B2 group and the conventional acupoints group, 80 cases in each one. The patients in the EX-B2 group received EA at the symmetrical 2 acupoints of the bilateral EX-B2 on the lesion part. The patients in the conventional acupoints group received EA at the tender point of the lesion part, Zhibian（ 秩边BL54）, Huantiao（环跳 GB30）,weǐzhōng（委中BL40）, Chéngshān（承山BL57） and Fúyáng（跗阳BL59） on the affected side. The retain time of the needles is both 45 min. The treatment of the two groups is 3 times a week and for a connective 20 times. The modified Assessment Criteria for Low Lumbar Pain of Japanese Orthopedic Association（JOA）,Visual Analogue Scale（VAS） were evaluated before and after the treatment and at the 6-month follow up.Results：（1） Effective outcomes. JOA score： The JOA score of the patients in the EX-B2 group after treatment was（20.89 士 3.43）, and was（19.35 ±4.02） on the follow-up. Compared with the JOA score（12.35 ±4.42） in the same group before the treatment, there were statistical significant higher（both P0.05）. The JOA score in the EX-B2 group after treatment and on the follow-up were both higher than that of the conventional acupoints group at the same time point（both P0.05）. VAS score： The VAS score of the patients in the EX-B2 group on the 24 h after the first treatment was（4.09 ± 1.81）, and was（2.11 ± 1.30） after the treatment. Compared with the VAS score（4.09 ± 1.81） in the same group before the treatment, there were statistical significant lower（both P0.05）. The VAS score in the EX-B2 group on the 24 h after the first treatment and after treatment showed no statistical difference展开更多
Lumber moisture content(LMC) is the important parameter to judge the dryness of lumber and the quality of wooden products.Nevertheless the data acquired are mostly redundant and incomplete because of the complexity of...Lumber moisture content(LMC) is the important parameter to judge the dryness of lumber and the quality of wooden products.Nevertheless the data acquired are mostly redundant and incomplete because of the complexity of the course of drying,by interference factors that exist in the dryness environment and by the physical characteristics of the lumber itself.To improve the measuring accuracy and reliability of LMC,the optimal support vector machine(SVM) algorithm was put forward for regression analysis LMC.Environmental factors such as air temperature and relative humidity were considered,the data of which were extracted with the principle component analysis method.The regression and prediction of SVM was optimized based on the grid search(GS) technique.Groups of data were sampled and analyzed,and simulation comparison of forecasting performance shows that the main component data were extracted to speed up the convergence rate of the optimum algorithm.The GS-SVM shows a better performance in solving the LMC measuring and forecasting problem.展开更多
基金supported by the Natural Science Foundation of Jiang-su Province(No.BK20181402)the National Natural Science Foundation of China(51878354)+3 种基金National Key R&D Program of China,the Open Fund Project from Key Laboratory of Concrete and Pre-stressed Concrete Structure of Ministry of Education(Southeast university)the China Postdoctoral Science Foundation(2015M580382)Jiangsu Postdoctoral Science Foundation Project(1501037A)Qing Lan Project,and a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘In order to investigate the influence of length and compression directions upon behaviour of parallel bamboo strand lumber(PBSL)specimens,240 axial compression tests have been performed.With three similar one different typical failure modes,the mechanical performance for PBSL specimens under compression parallel to grain and perpendicular to grain are different as a whole.From the point of the characteristic values,the compression strength parallel to grain is 2.1 times of the compression strength perpendicular to grain.The elastic modulus for compression parallel to grain is 3.64 times of the compression strength perpendicular to grain.While the compression ratios along two compression directions are equal to each other.The bigger Poisson ratios for one typical side surface is 3.93 times of that for another typical side surface for PBSL specimens under compression perpendicular to grain,and the bigger value is equal to that for PBSL specimens under compression parallel to grain.Length can influence the mechanical properties of the PBSL specimens.The size 50 mm×50 mm×100 mm should be good choice for the standard or code to measure the compression strength.PBSL materials have better ductility under compression parallel to grain than that under compression perpendicular to grain.Stress-strain relationship models were proposed for PBSL specimens under compression parallel to grain and perpendicular to grain,respectively.These proposed models gave a good agreement with the test results.
基金This paper was supported by the National Natural Science Foundation of China （No. 30271053）
文摘A comparative study was conducted on liquid penetration of the freeze-drying and air-drying sapwood and heartwood lumber of plantation Chinese fir （Cunninghamia lanceolata）. The maximum amount of dyeing solution uptake by the capillary rise method was used to evaluate the liquid penetration properties of the treated wood. The pit aspiration ratio was determined by semithin section method. Changes in wood microstructure were investigated using scanning electron microscopy. The results showed that compared with air drying, the freeze drying had a significant effect on liquid penetration of sapwood and heartwood of Chinese fir. The liquid penetration of sapwood is significantly higher than that of the heartwood for both drying treatments. Low pit aspiration ratio and cracks of pits membrane of some bordered pits are the main reasons for increasing liquid penetration after freeze drying treatment.
基金Supported by Shanghai Traditional Chinese Medicine Science and Technology innovation Project:no.ZYKC201601002~~
文摘Objective： To compare the effect differences of electroacupuncture（EA） at Jiajǐ（夹脊 EX-B2） and conventional acupoints for lumbar intervertebral disc herniation（LIDH） and the factors influenced the effect during the way of data mining.Methods： A total of 160 patients of LIDH were randomly assigned into the EX-B2 group and the conventional acupoints group, 80 cases in each one. The patients in the EX-B2 group received EA at the symmetrical 2 acupoints of the bilateral EX-B2 on the lesion part. The patients in the conventional acupoints group received EA at the tender point of the lesion part, Zhibian（ 秩边BL54）, Huantiao（环跳 GB30）,weǐzhōng（委中BL40）, Chéngshān（承山BL57） and Fúyáng（跗阳BL59） on the affected side. The retain time of the needles is both 45 min. The treatment of the two groups is 3 times a week and for a connective 20 times. The modified Assessment Criteria for Low Lumbar Pain of Japanese Orthopedic Association（JOA）,Visual Analogue Scale（VAS） were evaluated before and after the treatment and at the 6-month follow up.Results：（1） Effective outcomes. JOA score： The JOA score of the patients in the EX-B2 group after treatment was（20.89 士 3.43）, and was（19.35 ±4.02） on the follow-up. Compared with the JOA score（12.35 ±4.42） in the same group before the treatment, there were statistical significant higher（both P0.05）. The JOA score in the EX-B2 group after treatment and on the follow-up were both higher than that of the conventional acupoints group at the same time point（both P0.05）. VAS score： The VAS score of the patients in the EX-B2 group on the 24 h after the first treatment was（4.09 ± 1.81）, and was（2.11 ± 1.30） after the treatment. Compared with the VAS score（4.09 ± 1.81） in the same group before the treatment, there were statistical significant lower（both P0.05）. The VAS score in the EX-B2 group on the 24 h after the first treatment and after treatment showed no statistical difference
基金supported by the Natural Science Foundation of China(Grant No.31470715),(Grant No.31470714)the Fundamental Research Funds for the Central Universities(2572016EBT1)
文摘Lumber moisture content(LMC) is the important parameter to judge the dryness of lumber and the quality of wooden products.Nevertheless the data acquired are mostly redundant and incomplete because of the complexity of the course of drying,by interference factors that exist in the dryness environment and by the physical characteristics of the lumber itself.To improve the measuring accuracy and reliability of LMC,the optimal support vector machine(SVM) algorithm was put forward for regression analysis LMC.Environmental factors such as air temperature and relative humidity were considered,the data of which were extracted with the principle component analysis method.The regression and prediction of SVM was optimized based on the grid search(GS) technique.Groups of data were sampled and analyzed,and simulation comparison of forecasting performance shows that the main component data were extracted to speed up the convergence rate of the optimum algorithm.The GS-SVM shows a better performance in solving the LMC measuring and forecasting problem.
