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961.
非均匀圆柱型正交各向异性圆板的弯曲问题 总被引:1,自引:1,他引:0
本文研究了非均匀圆柱型正交各向异性圆板的弯曲问题,求得了折算刚度随半径按指数函数规律变化的非均匀圆柱型正交各向异性圆板在横向均布载荷作用下的通解,并给出了周边固定夹支条件下的精确解。 相似文献
962.
Lucía Castro-Vzquez María Victoria Lozano Virginia Rodríguez-Robledo Joaquín Gonzlez-Fuentes Pilar Marcos Noemí Villaseca Maria Mar Arroyo-Jimnez Manuel J. Santander-Ortega 《Molecules (Basel, Switzerland)》2021,26(19)
Orange peel by-products generated in the food industry are an important source of value-added compounds that can be potentially reused. In the current research, the effect of oven-drying (50–70 °C) and freeze-drying on the bioactive compounds and antioxidant potential from Navelina, Salustriana, and Sanguina peel waste was investigated using pressurized extraction (ASE). Sixty volatile components were identified by ASE-GC-MS. The levels of terpene derivatives (sesquitenenes, alcohols, aldehydes, hydrocarbons, and esters) remained practically unaffected among fresh and freeze-dried orange peels, whereas drying at 70 °C caused significative decreases in Navelina, Salustriana, and Sanguina peels. Hesperidin and narirutin were the main flavonoids quantified by HPLC-MS. Freeze-dried Sanguina peels showed the highest levels of total-polyphenols (113.3 mg GAE·g−1), total flavonoids (39.0 mg QE·g−1), outstanding values of hesperedin (187.6 µg·g−1), phenol acids (16.54 mg·g−1 DW), and the greatest antioxidant values (DPPH•, FRAP, and ABTS•+ assays) in comparison with oven-dried samples and the other varieties. Nanotechnology approaches allowed the formulation of antioxidant-loaded nanoemulsions, stabilized with lecithin, starting from orange peel extracts. Those provided 70–80% of protection against oxidative UV-radiation, also decreasing the ROS levels into the Caco-2 cells. Overall, pressurized extracts from freeze-drying orange peel can be considered a good source of natural antioxidants that could be exploited in food applications for the development of new products of commercial interest. 相似文献
963.
In this paper,based on the mixed-type theory developed by the same authors.atheoretical analysis is presented for the stability of laminated composite circular conicalshells under external pressure.The formulas for critical external pressure are obtained byusing the potential energy variation principle.Very good agreement is shown between thetheoretical prediction of critical external pressure and the experimental data.Finally,theinfluence of some parameters on critical external pressure is discussed numerically.Themixed-type theory developed by the same authors and the results obtained in this paperare very useful in aerospace engineering design. 相似文献
964.
有限长圆柱体轴对称问题的弹性理论解 总被引:1,自引:0,他引:1
本文利用H变换和Stockes变换.导出双变量函数及其编导数在闭区间上完整的双级数表达式,从而求得弹性力学中有限长圆柱体的轴对称问题的一般解析解.文中以轴向拉伸圆柱体为例,考虑不同的外力作用区域,分析了圆柱体上位移和应力的分布.本文所提的方法具有一般性.可以用来求解其它学科领域中有关柱坐标的轴对称边值问题. 相似文献
965.
In this paper by using the concept of mixed boundary functions,an analytical method is proposed for a mixed boundary value problem of circular plates.The trial functions are constructed by using the series of particular solutions of the biharmonic equations in the polar coordinate system.Three examples are presented to show the stability and high convergence rate of the method. 相似文献
966.
Application of the modified iteration method to nonlinear postbuckling analysis of thin circular plates 总被引:1,自引:0,他引:1
李东 《应用数学和力学(英文版)》1991,12(12):1143-1148
In this paper,the modified iteration method is further generalized to the study ofaxisymmetrical postbuckling of thin circular plates and hereby a new approximate analyticsolution of the problem is obtained.Further utilizations of this method to postbucklinganalyses of plates of more complicated structure are expected. 相似文献
967.
阻尼介质中简支圆板在大挠度时的塑性动力响应 总被引:3,自引:0,他引:3
本文从理论上分析了受矩形脉冲荷载作用的阻尼介质中简支理想刚塑性圆板在大挠度时的塑性动力响应.文中给出了在中载和高载情况下各相的解析解. 相似文献
968.
戴世强 《应用数学和力学(英文版)》1984,5(4):1469-1478
In this paper, on the basis of Boussinesq’s shallow water theory, we establish the basic equations governing the motion of a stratified fluid, a kind of the generalized Boussinesq equations. And then by way of them, we study the weak interaction of two pairs of obliquely colliding solitary waves, give the second-order approximate solutions for wave profiles and maximum amplitudes, as well as conclude that when the included angle between the directions of propagation of impinging solitary waves is less than 120°, the effect of oblique interaction is stronger than that of the head-on one, but when the angle concerned is greater than 120°, the former is slightly weaker than the latter. 相似文献
969.
刘曾荣 《应用数学和力学(英文版)》1987,8(1):31-35
In this paper, we study the solution of differential equation with Dirac function and Heaviside function, arising from discontinuous and impulsive excitation. Firstly, according to the theory of differential equation, we suggest, then we derive the equation of x
1
(t) and x
2
(t) by terms of property of distribution, and by solving x
1
(t) and x
2
(t) we obtain x(t); finally, we make a thorough investigation about periodic impulsive parametric excitation. 相似文献
970.