基于动态指纹图谱的奶粉中糊精添加量检测方法

采用动态非线性化学指纹图谱法对奶粉中添加的糊精进行定量分析。利用"硫酸-硫酸锰-丙酮-溴酸钠"为振荡体系,先向奶粉中添加不同量的糊精,配成掺杂糊精的奶粉标样。通过非线性化学指纹图谱法对奶粉标样进行测定,运用最小二乘法,分别拟合其诱导时间和停波时间相对于奶粉中添加糊精含量之间的一元线性关系,可求出奶粉中添加的糊精含量。实验表明,当奶粉中添加的糊精质量分数在0~30%范围内时,糊精含量与诱导时间及停波时间线性关系良好,决定系数R~2为0.997 2~0.999 1,回收率为94.00%~104.89%,相对标准偏差为0.17%~1.17%,检测范围为0~30%,检出限为1.3×10~(-3)~4.7×10~(-3)mg/g。方法准确度高,操作简单,是一种切实可行的测定奶粉中添加糊精的方法,也可作为复杂样本中其他成分定量分析借鉴的方法。     

表面形态抗冲蚀三维数值模拟

利用有限元软件ANSYS／LS—DYNA,对光滑试件和凸包形、凹槽形表面形态的45号钢试件的耐冲蚀性能,进行了三维数值模拟,计算冲蚀磨损过程中等效应力的变化情况。结果表明,试件数值模拟的冲蚀情况与试验吻合良好。这说明选用适当的ANSYS／LS—DYNA单元类型和设置合理的参数,完全可以实现对光滑试件和两种不同的表面形态试件的耐冲蚀性能的数值模拟,本文对于研究表面形态耐冲蚀机理和进行冲蚀磨损预报有一定的借鉴意义。     

渐近非扩张算子方程的隐式迭代序列收敛性

隐式迭代法是不动点理论的重要内容,非渐近非扩张算子方程也被广泛使用,通过对渐近非扩张算子方程的隐式迭代法的研究,利用渐近非扩张算子的概念和性质,得到了渐近非扩张算子方程隐式迭代解的收敛性的充分条件,完善了对其收敛性研究的理论．     

基于Logistic与Gompertz非线性模型的 野牛草克隆生长模拟与分析

 【目的】揭示野牛草克隆生长规律,建立理想的克隆生长模型,为进一步开发克隆植物的利用价值、选育优良品种提供参考。【方法】运用Logistic和Gompertz 两种非线性生长模型,分别对同质及异质环境下各同质小生境内野牛草克隆分株增殖数据进行曲线拟合和分析。【结果】两种模型均能模拟野牛草的生长曲线,但Logistic生长模型拟合优度更高,与实测值也更接近;进一步分析Logistic模型拟合参数发现,不同生境下野牛草克隆片段的分株增殖拐点时期集中在12.95—14.00周,但拐点分株增殖量存在显著差异;与同质环境相比,资源的异质性分布有利于野牛草克隆分株增殖。【结论】野牛草克隆生长符合Logistics模型,环境的异质性与分株增殖速率密切相关,而与分株增殖的拐点时间无显著相关;认为异质生境下相连克隆片段及分株间的生理整合,可有效提高资源的利用效率。     

Intelligent Control of the Nonlinear Seismic Response of a 3 Story Benchmark Building

Intelligent materials, control devices and intelligent control algorithm research and development in recent years have opened a new world for seismic resistance and disaster reduction in civil engineering. We designed and fabricated a new piezoelectric friction damper. In our research, we regarded the piezoelectric friction damper as the control device. We proposed a fuzzy control algorithm for reducing nonlinear seismic response of a 3 story benchmark building and established the interactive relationships between structural responses and fuzzifier factors, defuzzifier factor. A numerical simulation is carried out to analyze the nonlinear seismic responses of the controlled 3 story benchmark building. The simulation results are compared to those of other control strategies. The results show that the fuzzy control can reduce the nonlinear seismic response of 3 story benchmark building and minimize the structural damage caused by strong earthquakes.     

农用车翻车保护结构非线性有限元分析

翻车和落物保护结构是翻车时使司机减少被挤伤可能性的安全装置。为此,针对其使用要求设计的农用车ROPS结构,在国家标准GB/T 17922-1999实验室静态试验方法基础上,分析了翻车保护结构的变形过程,在加载过程中出现了材料非线性和几何非线性,并进一步对翻车和落物保护结构进行了非线性有限元计算。模型试验与计算结果吻合,表明计算方法是可行的。     

the rationality of plane model simplifying three dimension frame in seismic response analysis

A finite element model based on the flexibility method and a fiber section model of nonlinear beam column elements was adopted within the OpenSees framework. A typical multistory reinforced concrete 3D frame designed in accordance with the Chinese building code and a representative plane frame parallel to the X axis were used as examples. The relationships of the responses obtained from the plane and 3D models were studied by comparing global and local seismic responses of the frame, and by taking the responses of the 3D model under unidirectional earthquake action as a medium for comparison. Because the results show the global responses of the plane model are similar to those of the 3D model, it is reasonable to replace the 3D model with the plane model when examining global seismic responses. The local responses are evidently different. For the plane model under unidirectional action, numerous plastic hinges develop at the beam ends. Many more plastic hinges at column ends exist than in beams for the 3D model under bi directional action. Column ductility demands obviously exceed those of beams. The frame tends to develop a column sway mechanism, implying that simplified plane analysis model significantly underestimates the seismic responses of the 3D frame column.     

番茄应力松弛特性的研究

以番茄品种辽园多丽的完整果实为试样,根据弹性力学Hertz理论及粘弹性理论,从平板压缩试验及应力松弛试验研究中提取力学一流变学性质参数,利用MATLAB软件和SPSS软件做非线性回归,建立了Maxwell力学模型.结果表明:3个成熟期的番茄纵向压缩形变在9mmm之内都属于弹性形变,且在瞬时形变为6mm下,应力松弛时间都不超过120s.     

基于SPSS相容性林分生物量非线性模型研究

林分生物量是森林生态系统最基本的数量特征,是研究许多林业问题和生态问题的基础.建立林分生物量模型是进行林分生物量估测的主要手段.以往所构建模型存在一个严重的缺陷,即各分量模型与总量模型之间不相容.本研究根据闽江流域杉木林分的生物量实测数据,从模型相容性的定义出发,分析各分量的代数关系,利用SPSS统计分析软件构建了林分各分量的相容性模型.研究结果表明:利用SPSS统计分析软件能够快速地构建各种林分非线性模型;本研究所构建的相容性林分生物量非线性模型预测精度较高,可用于实际生产中,且所采用的方法具有较好的通用性.