The following theorem is proved: A knight’s tour exists on all 3 x n chessboards with one square removed unless: n is even, the removed square is (i, j) with i + j odd, n = 3 when any square other than the center squ...The following theorem is proved: A knight’s tour exists on all 3 x n chessboards with one square removed unless: n is even, the removed square is (i, j) with i + j odd, n = 3 when any square other than the center square is removed, n = 5, n = 7 when any square other than square (2, 2) or (2, 6) is removed, n = 9 when square (1, 3), (3, 3), (1, 7), (3, 7), (2, 4), (2, 6), (2, 2), or (2, 8) is removed, or when square (1, 3), (2, 4), (3, 3), (1, n – 2), (2, n – 3), or (3, n – 2) is removed.展开更多
在硬件在回路仿真系统中,模型需与数据采集卡之间进行实时数据的采集和交换,Simulink下Real Time Workspace工具箱提供了与硬件之间的实时数据采集和交换,但是工具箱并不支持市面上所有采集板卡的类型,给用户对采集板卡选型带来一定局...在硬件在回路仿真系统中,模型需与数据采集卡之间进行实时数据的采集和交换,Simulink下Real Time Workspace工具箱提供了与硬件之间的实时数据采集和交换,但是工具箱并不支持市面上所有采集板卡的类型,给用户对采集板卡选型带来一定局限性。因此本文使用Simulink中S-Function模块编写不同采集板卡的硬件驱动,证明只要是数据采集工具箱支持的板卡型号,都可以用S-Function进行模块化硬件驱动编写,解决了Simulink中Real Time Workspace工具箱给用户在使用Simulink建模过程中对板卡选型的局限性这一问题。展开更多
This work aimed to help the bamboo industry develop methodology for producing imperfection-free bamboo boards that can serve either decorative or structural benefit to consumers seeking to engage with the bioeconomy.S...This work aimed to help the bamboo industry develop methodology for producing imperfection-free bamboo boards that can serve either decorative or structural benefit to consumers seeking to engage with the bioeconomy.Specifically,softened and slotted bamboo tubes were handled by a roller device with nails to render crack-free flattened bamboo board.Softening temperature and time were optimized herein according to findings regarding chemical composition and board mechanical properties.The optimal softening parameters for saturated steam heat treatment is proved to be 160°C for 8 min.The flattened bamboo board possesses an increased bending strength of 101.5 MPa and a decreased bending modulus of 7.7 GPa,being compared with only-softened bamboo.The corresponding changing mechanism is determined in-depth by the micro-morphological and mechanical results based on in-situ SEM and AFM technologies.Under the action of nails and rolling processes,the bamboo texture becomes compact with crushed and fragmented conduit walls.The resulting cell cavity then becomes stretched and compressed,taking on a morphology which allows for the mechanical penalties associated with flattening to be avoided.According to the micro-mechanical results obtained by AFM,compared with unflatten bamboo,the Young’s modulus of the cell membrane in transverse direction(YT)decreases to 1.00 GPa while the corresponding Young’s modulus in radial direction(YR)increases to 7.29 GPa.展开更多
The World Journal of Hepatology(WJH)was launched in October 2009.It mainly publishes articles reporting research findings in the field of hepatology,covering a wide range of topics,including viral hepatitis B and C,no...The World Journal of Hepatology(WJH)was launched in October 2009.It mainly publishes articles reporting research findings in the field of hepatology,covering a wide range of topics,including viral hepatitis B and C,non-alcoholic fatty liver disease,alcoholic liver disease,autoimmune and chronic cholestatic liver disease,drug-induced liver injury,cirrhosis,liver failure,hepatocellular carcinoma,coronavirus disease 2019-related liver conditions,etc.As of December 31,2020,the WJH has published 1349 articles,among which,the total cites is 18995 and the average cites per article is 14.In celebrating the New Year,we are pleased to share with you special a New Year’s greeting from the WJH Editors-in-Chief,along with a detailed overview of the journal’s submission,peer review and publishing metrics from 2020.In all,we are appreciative for the substantive support and submissions from authors worldwide,and the dedicated efforts and expertise provided by our invited reviewers and editorial board members.展开更多
This paper analyzes the observing results of vacuum degree in the the Jialichen bridge-head experimental site .The cause of vacuum degree developing below groundwater table is pointed out. The influence of vacuum degr...This paper analyzes the observing results of vacuum degree in the the Jialichen bridge-head experimental site .The cause of vacuum degree developing below groundwater table is pointed out. The influence of vacuum degree above the ground water table on pore water pressure is discussed. The results show that vacuum degree decreases along the depth because resistance. The resistance in the PVDS is lowest, in the silt is highest. Vacuum degree below groundwater table is produced mainly by dewatering or by escaping of sealed air from the end of flexible pipe. Vacuum degree above the ground water table in the sand drains makes great effect on pore water pressure. In the silt the pore water pressure does not change with the variation of vacuum degree under membrane in a short time.展开更多
文摘The following theorem is proved: A knight’s tour exists on all 3 x n chessboards with one square removed unless: n is even, the removed square is (i, j) with i + j odd, n = 3 when any square other than the center square is removed, n = 5, n = 7 when any square other than square (2, 2) or (2, 6) is removed, n = 9 when square (1, 3), (3, 3), (1, 7), (3, 7), (2, 4), (2, 6), (2, 2), or (2, 8) is removed, or when square (1, 3), (2, 4), (3, 3), (1, n – 2), (2, n – 3), or (3, n – 2) is removed.
文摘在硬件在回路仿真系统中,模型需与数据采集卡之间进行实时数据的采集和交换,Simulink下Real Time Workspace工具箱提供了与硬件之间的实时数据采集和交换,但是工具箱并不支持市面上所有采集板卡的类型,给用户对采集板卡选型带来一定局限性。因此本文使用Simulink中S-Function模块编写不同采集板卡的硬件驱动,证明只要是数据采集工具箱支持的板卡型号,都可以用S-Function进行模块化硬件驱动编写,解决了Simulink中Real Time Workspace工具箱给用户在使用Simulink建模过程中对板卡选型的局限性这一问题。
基金This research was funded by Financial support from the National Natural Science Foundation of China(Nos.61601227,31971740)China Postdoctoral Science Foundation(2017M621598)+4 种基金Nature Science Foundation of Jiangsu Province(BK20160939)Key University Science Research Project of Jiangsu Province(17KJA220004)Jiangsu Agricultural Science and Technology Independent Innovation Project(CX(18)3033)Science and Technology Program of Fujian Province(2019N3014)Open Fund of Key Laboratory of National Forestry and Grassland Administration/Beijing for Bamboo&Rattan Science and Technology(ICBR-2020-08).
文摘This work aimed to help the bamboo industry develop methodology for producing imperfection-free bamboo boards that can serve either decorative or structural benefit to consumers seeking to engage with the bioeconomy.Specifically,softened and slotted bamboo tubes were handled by a roller device with nails to render crack-free flattened bamboo board.Softening temperature and time were optimized herein according to findings regarding chemical composition and board mechanical properties.The optimal softening parameters for saturated steam heat treatment is proved to be 160°C for 8 min.The flattened bamboo board possesses an increased bending strength of 101.5 MPa and a decreased bending modulus of 7.7 GPa,being compared with only-softened bamboo.The corresponding changing mechanism is determined in-depth by the micro-morphological and mechanical results based on in-situ SEM and AFM technologies.Under the action of nails and rolling processes,the bamboo texture becomes compact with crushed and fragmented conduit walls.The resulting cell cavity then becomes stretched and compressed,taking on a morphology which allows for the mechanical penalties associated with flattening to be avoided.According to the micro-mechanical results obtained by AFM,compared with unflatten bamboo,the Young’s modulus of the cell membrane in transverse direction(YT)decreases to 1.00 GPa while the corresponding Young’s modulus in radial direction(YR)increases to 7.29 GPa.
文摘The World Journal of Hepatology(WJH)was launched in October 2009.It mainly publishes articles reporting research findings in the field of hepatology,covering a wide range of topics,including viral hepatitis B and C,non-alcoholic fatty liver disease,alcoholic liver disease,autoimmune and chronic cholestatic liver disease,drug-induced liver injury,cirrhosis,liver failure,hepatocellular carcinoma,coronavirus disease 2019-related liver conditions,etc.As of December 31,2020,the WJH has published 1349 articles,among which,the total cites is 18995 and the average cites per article is 14.In celebrating the New Year,we are pleased to share with you special a New Year’s greeting from the WJH Editors-in-Chief,along with a detailed overview of the journal’s submission,peer review and publishing metrics from 2020.In all,we are appreciative for the substantive support and submissions from authors worldwide,and the dedicated efforts and expertise provided by our invited reviewers and editorial board members.
文摘This paper analyzes the observing results of vacuum degree in the the Jialichen bridge-head experimental site .The cause of vacuum degree developing below groundwater table is pointed out. The influence of vacuum degree above the ground water table on pore water pressure is discussed. The results show that vacuum degree decreases along the depth because resistance. The resistance in the PVDS is lowest, in the silt is highest. Vacuum degree below groundwater table is produced mainly by dewatering or by escaping of sealed air from the end of flexible pipe. Vacuum degree above the ground water table in the sand drains makes great effect on pore water pressure. In the silt the pore water pressure does not change with the variation of vacuum degree under membrane in a short time.
