Neural Network Inference of Molar Mass Distributions of Peptides during Tailor-Made Enzymatic Hydrolysis of Cheese Whey: Effects of pH and Temperature

The fine-tuning of the enzymatic hydrolysis of proteins may provide a pool of peptides with predefined molar mass distributions. However, the complex mixture of molecules (peptides and amino acids) that results after the proteolysis of cheese whey turns unfeasible the assessment of individual species. In this work, a hybrid kinetic model for the proteolysis of whey by alcalase, multipoint-immobilized on agarose, is presented, which takes into account the influence of pH (8.0-10.4) and temperature (40-55 degrees C) on the activity of the enzyme. Five ranges of peptides' molar mass have their reaction rates predicted by neural networks (NNs). The output of NNs trained for constant pH and temperatures was interpolated, instead of including these variables in the input vector of a larger NN. Thus, the model complexity was reduced. Coupled to differential mass balances, this hybrid model can be employed for the online inference of peptides' molar mass distributions. Experimental kinetic assays were carried out using a pH-stat, in a laboratory-scale (0.03 L) batch reactor. The neural-kinetic model was integrated to a supervisory system of a bench-scale continually stirred tank reactor (0.5 L), providing accurate predictions during validation tests.     

Transition State and Catastrophe Set

The study on transition states is one of the most important pathways to understand the essence of chemical reactions. With the development of femtoseeond pulse technique, Zewail et al. have carried out a number of experimental studies on the transition states, while the theoretical chemists has a great interest in the topic. In the previous     

Second-Order Necessary Optimality Conditions for Some State-Constrained Control Problems of Semilinear Elliptic Equations

In this paper we are concerned with some optimal control problems governed by semilinear elliptic equations. The case of a boundary control is studied. We consider pointwise constraints on the control and a finite number of equality and inequality constraints on the state. The goal is to derive first- and second-order optimality conditions satisfied by locally optimal solutions of the problem. Accepted 6 May 1997     

控制论中动态系统的数学模型及分析

控制论中动态系统的非线性系统分析,主要在定性分析上,本文对稳定性定理进行了探讨     

用状态变量法研究轴承-转子系统稳定性

在计算轴承－ 转子系统的稳定性和轴心轨迹时,为克服特征根法、Ｆｏｕｒｉｅｒ 级数法等计算方法的局限性,提出了用状态方程的时域分析法计算流体润滑轴承在位移扰动、冲击载荷和不平衡激励等典型扰动下的轴心轨迹和判断稳定性的方法,根据当前时刻的状态变量值,只要进行一次矩阵乘法即可得到下一时刻的状态变量值,具有不受步长大小的限制而保持较高的计算精度。同时还讨论了小扰动理论的使用条件。     

石油焦热解动力学参数及其补偿效应

通过对石油焦热解的热重分析,发现石油焦热解动力学参数受升温速率、热解率等实验条件影响较大,并归纳出石油焦热解的动力学补偿效应表达式ｌｎＡ＝ ａ＋ ｂＥ,从而建立石油焦热解动力学参数之间的关系     

状态反馈H∞控制在二级倒立摆平衡系统中的应用

应用Ｈ∞状态反馈和Ｋａｌｍａｎ滤波相结合的方法,对二级倒立摆平衡系统进行控制。仿真研究表明：二者相结合构成的控制器,在模型参数摄动且有干扰信号作用的情况下,比ＬＱＧ控制具有更强的鲁棒稳定性和抗干扰能力。     

广西防城港市的族群认同(下)

从污名认同、中华民族认同、国家认同、政治政策认同、地域认同等方面对防城港市各族群的特殊认同方式进行了论述。     

由某些函数构造的状态变权

研究状态变权的构造问题,给出一种由多元函数和已知状态变权构造新状态变权和三种由多元函数直接构造状态变权的方法。特别地,证明了文[5]由状态均值构造状态变权的方法都可看作是函数构造状态变权的特例,并进一步给出一种基于几何均值的状态变权构造方法。     

Magnetospectroscopy of double HgTe/CdHgTe QWs with inverted band structure in high magnetic fields up to 30 T

Magnetoabsorption in far and mid IR ranges in double HgTe/CdHgTe quantum wells with inverted band structure has been studied in high magnetic fields up to 30 T. Numerous intraband and interband transitions have been revealed in the spectra and interpreted within axial 8 × 8 k·p model. Splitting of dominant magnetoabsorption lines resulting from optical transitions from hole-like zero-mode Landau level has been discovered and discussed in terms of a built-in electric field and collective phenomena.