对木醋杆菌产细菌纤维素的条件进行优化,并通过正交和单因素实验摸索细菌纤维素加固文物纸质的条件。结果显示,葡萄糖为碳源、酵母浸粉+蛋白胨为氮源、接种时间为36 h、接种量为10%、温度为30℃时产细菌纤维素最佳;细菌纤维素浓度1.0%、...对木醋杆菌产细菌纤维素的条件进行优化,并通过正交和单因素实验摸索细菌纤维素加固文物纸质的条件。结果显示,葡萄糖为碳源、酵母浸粉+蛋白胨为氮源、接种时间为36 h、接种量为10%、温度为30℃时产细菌纤维素最佳;细菌纤维素浓度1.0%、D M A c浓度30%、再生温度30℃、再生时间9 m i n为文物纸质最适加固条件,甘油浓度10%、塑化时间5 min、无纺布做底衬层材料为加固纸张质感改善条件,处理后纸张抗张强度上升一倍,白度、光泽度无显著变化,兼顾了纸张的柔软度,为生物材料在文物保护方面的应用提供了技术支持。展开更多
为增强物场模型构建方法的指引性及物场模型变换的针对性,拓展经由物场模型变换进行产品创新的路径,提出一种基于物场模型构建与进化变换的创新设计模型。面向产品改进型设计,提出基于系统结构功能分析、因果分析以及完备性分析的物场...为增强物场模型构建方法的指引性及物场模型变换的针对性,拓展经由物场模型变换进行产品创新的路径,提出一种基于物场模型构建与进化变换的创新设计模型。面向产品改进型设计,提出基于系统结构功能分析、因果分析以及完备性分析的物场模型构建方法,为改进创新提供多维度的解题方向;依据TRIZ(Theory of Inventive Problem Solving)的物场模型进化趋势构建物场模型进化树;基于物场模型进化路线提出问题物场模型及作用充分物场模型的变换规则及实施路径;结合扫雪除冰机的改进设计实例验证设计模型的有效性。展开更多
This article focuses on the positivity and the asymptotic stability of fractional-order linear time-delay systems(FOLTDSs)which are composed of N(N≥2)subsystems.Firstly,a sufficient and necessary condition is given t...This article focuses on the positivity and the asymptotic stability of fractional-order linear time-delay systems(FOLTDSs)which are composed of N(N≥2)subsystems.Firstly,a sufficient and necessary condition is given to ensure the positivity of FOLTDSs.The solutions of the studied systems are obtained by using the Laplace transform method,and it can be observed that the positivity of FOLTDSs is completely determined by the series of matrices and independent of the magnitude of time-delays.Secondly,a theorem is given to prove the asymptotic stability of positive FOLTDSs.By considering the monotonicity and asymptotic properties of systems with constant time-delay,it is further shown that the asymptotic stability of positive FOLTDSs is independent of the time-delay.Next,a state-feedback controller,whose gain matrix is derived by resolving a linear programming question,is designed such that the state variables of the systems are nonnegative and asymptotically convergent.When the order of the FOLTDSs is greater than one,by utilizing a proposed property of Caputo derivative,a sufficient condition for the positivity of FOLTDS is presented.Finally,simulation examples are presented to verify the validity and practicability of the theoretical analysis.展开更多
文摘对木醋杆菌产细菌纤维素的条件进行优化,并通过正交和单因素实验摸索细菌纤维素加固文物纸质的条件。结果显示,葡萄糖为碳源、酵母浸粉+蛋白胨为氮源、接种时间为36 h、接种量为10%、温度为30℃时产细菌纤维素最佳;细菌纤维素浓度1.0%、D M A c浓度30%、再生温度30℃、再生时间9 m i n为文物纸质最适加固条件,甘油浓度10%、塑化时间5 min、无纺布做底衬层材料为加固纸张质感改善条件,处理后纸张抗张强度上升一倍,白度、光泽度无显著变化,兼顾了纸张的柔软度,为生物材料在文物保护方面的应用提供了技术支持。
文摘为增强物场模型构建方法的指引性及物场模型变换的针对性,拓展经由物场模型变换进行产品创新的路径,提出一种基于物场模型构建与进化变换的创新设计模型。面向产品改进型设计,提出基于系统结构功能分析、因果分析以及完备性分析的物场模型构建方法,为改进创新提供多维度的解题方向;依据TRIZ(Theory of Inventive Problem Solving)的物场模型进化趋势构建物场模型进化树;基于物场模型进化路线提出问题物场模型及作用充分物场模型的变换规则及实施路径;结合扫雪除冰机的改进设计实例验证设计模型的有效性。
基金the National Natural Science Foundation of China under Grant Nos.61967001,12062004,and 11771263the Innovation Project of Guangxi University for Nationalities Graduate Education(gxun-chxps201908 and gxun-chxkc201903)the Guangxi Natural Science Foundation(2019GXNSFAA185007 and 2020GXNSFAA297240)。
文摘This article focuses on the positivity and the asymptotic stability of fractional-order linear time-delay systems(FOLTDSs)which are composed of N(N≥2)subsystems.Firstly,a sufficient and necessary condition is given to ensure the positivity of FOLTDSs.The solutions of the studied systems are obtained by using the Laplace transform method,and it can be observed that the positivity of FOLTDSs is completely determined by the series of matrices and independent of the magnitude of time-delays.Secondly,a theorem is given to prove the asymptotic stability of positive FOLTDSs.By considering the monotonicity and asymptotic properties of systems with constant time-delay,it is further shown that the asymptotic stability of positive FOLTDSs is independent of the time-delay.Next,a state-feedback controller,whose gain matrix is derived by resolving a linear programming question,is designed such that the state variables of the systems are nonnegative and asymptotically convergent.When the order of the FOLTDSs is greater than one,by utilizing a proposed property of Caputo derivative,a sufficient condition for the positivity of FOLTDS is presented.Finally,simulation examples are presented to verify the validity and practicability of the theoretical analysis.
