Mass and stiffness identification of particle beam system based on a dynamic effective mass method

We perform an investigation on identification of the complicated particle beam system, focusing on the occurrence and the mechanism of the resonant peaks. The concept concerning dynamic effective mass of the particle beam system is put forward, which realizes the decoupling of mass, stiffness, and damping. Excitation strategies, such as constant amplitude variable frequency sweep, are used during the testing process. The relationships between the dynamic effective mass of the particle beam system and the excitation frequency are recorded to study the mass and stiffness effects of the system. The results show that the variation of system stiffness and the negative mass are the main reasons for occurrence of resonant peaks. On the basis of the variation tendency of stiffness, we infer that the particle flow state transits from solid state to liquid state and thus, the whole frequency band is divided into three regions with an increase in excitation frequency. Within the region of solid state, resonant frequencies can be estimated roughly, which also proves reliability of the inference. The influence of burial depth and force amplitude on stiffness and mass of the system is investigated to reveal the tendency of all peaks and explain the jump phenomenon roughly.

Энергетический спектр и волновые функции электронов в туннельно-связанных сферических квантовых точках InAs/GaAs

The results of numerical calculation of the electron ground state energy and electron density in tunneled InAs/GaAs quantum dots forming a simple cubic superlattice are presented. The calculation is carried out in the framework of a modified effective mass method, taking into account the microscopic (atomic) structure of individual quantum dots, without taking into account the spin-orbit interaction and deformation effects. The dependence of the electron binding energy on the radius of the quantum dot R. It is shown that in the region R < 27 Å the electron binding energy is proportional to R in degree three.

The modified CPEM (cooked potato effective mass) method: an instrumental assessment of potato sloughing

The cooked potato effective mass (CPEM) method for potato sloughing assessment involves cooking the potato flakes on the sieve in a stirred water bath and periodically determining their effective mass during cooking. The final cooking curve divided into the cooking and breaking parts provides two parameters: the cooking time (CT) is the time required for starting disintegration, while the slope of the breaking part (SBP) describes the disintegration rate. The method enables a detailed analysis of the cooking properties in relation to the tuber density. The modified analysis of the cooking curve is based on polynomial approximation of the breaking part. It provides the time of cooking (CT_max) required to reach the maximal disintegration rate (MDR). These new parameters represent an alternative to the existing ones, their values are easier to obtain from the individual cooking curves, and therefore they can serve as a base for further development of the CPEM tests. &nbsp;

Sloughing in potatoes induced by tuber density and affected by variety

Two cultivars (Nicola and Saturna) largely distinguishing from each other in cooking behaviour and one cultivar (Agria) grown in six different cultivation regimes were tested by the CPEM (cooked potato effective mass) method for the potato sloughing assessment. The sloughing process is characterised by two cooking and disintegration stages, from which two basic CPEM parameters are derived: cooking time as the starting point of disintegration and the rate of the disintegration. Both parameters are analysed as functions of the tuber density in linear models of both stages. Significant differences in CPEM parameters and in the linear models were observed between different varieties. The data from two-year measurements were in basic agreement with our previous concept of the limited contribution of starch in the first cooking stage and of its more important role in the second disintegration stage of sloughing. The results indicated a close association between the mechanisms controlling sloughing and the tuber density in the cultivars Agria and Saturna. A different cooking behaviour was observed in the case of the typical salad cultivar Nicola with a considerably lower cooking time sensitivity to the tuber density.

Role of cultivation conditions in potato sloughing as indicated by CPEM method

The new CPEM (cooked potato effective mass) method was used to study the sloughing of a potato variety grown in two successive years in six regimes given by different levels and forms of fertilisation and irrigation. The sloughing process is characterized by the cooking time, i.e. the starting point of disintegration, and by the speed of disintegration. Both parameters are also evaluated in dependence on tuber density in linear models of cooking and disintegration stages. Effects of different cultivation regimes were observed in both stages. The sloughing sensitivity to tuber density expressed via the cooking time seemed to be a relatively stable variety parameter independent of growing conditions. The fertilisation reduced the level of sloughing, i.e. higher cooking time values (<i>P</i> < 0.0023), and at the same time lower disintegration rates (<i>P</i> < 0.006) were indicated for fertilised tubers. No influence of irrigation was observed in our study.