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排序方式: 共有482条查询结果,搜索用时 15 毫秒
1.
Ryszard Żywica Monika Modzelewska-Kapituła Katarzyna Tkacz 《International Journal of Food Properties》2018,21(1):1386-1394
The aim of the present study was to determine mathematical relationships between pH changes in beef 24 h post-slaughter and changes in the intensity of electrical current flowing through bull and heifer carcasses during high-voltage electrical stimulation. The electrical stimulation was applied 40 min postmortem for 120 s. The pH values of m. longissimus thoracis et lumborum were analyzed in the function of electrical current intensity changes and its change during electrical stimulation. Mathematical linear correlations of the y = ax ± b type were demonstrated between pH values at 2, 6, and 24 h postmortem and the initial (Ii) and ultimate (Iu) electrical current intensity values, the difference between them and the initial pH values determined before electrical stimulation. High multiple correlation coefficients (R2 = 0.416, α ≤ 0.001) between Iu and pH values 24 h post-slaughter enabled concluding that there is a possibility to predict a pH value of stimulated carcass with high accuracy, and thus also beef quality, based merely on the ultimate electrical current intensity values. 相似文献
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Cz. Woźniak 《Acta Mechanica》1989,78(1-2):81-94
Summary In this paper a new high efficiency C-O grid coupled with the potential flow solver based on the finite volume technique is given. It significantly reduces the CPU time and increases the computational efficiency. In order to improve the accuracy of traditional potential method a shock point operator is used to account for entropy correction. Some calculated results of 2D inviscid, viscous/inviscid interaction and 3D inviscid flow indicate that nonisentropic potential method produces results closer to Euler solution as well as experimental data, while its computational efforts are nearly the same as the usual isentropic potential method.With 9 Figures 相似文献
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Victor Chabanenko Roman Puźniak Adam Nabiałek Sergei Vasiliev Vladimir Rusakov Loh Huanqian Ritta Szymczak Henryk Szymczak Jan Jun Janusz Karpiński Vitaly Finkel 《Journal of Low Temperature Physics》2003,130(3-4):175-191
We present a study of magneto-thermal instabilities in polycrystalline MgB2 superconductor, by magnetic hysteresis loop measurements and by investigations of magnetic flux dynamics with a miniature Hall probe. Temperature and magnetic field ranges where the flux jumps may be observed have been determined. On the basis of measurements of the magnetic flux dynamics, an average magnetic diffusivity describing the process of the flux jump is estimated. This parameter is compared with the thermal and magnetic diffusivities calculated on the basis of available data for thermal conductivity, heat capacity and resistivity. It is shown that the estimated value of the field of the first flux jump is influenced significantly by the field dependence of specific heat. In order to explain the observed phenomenon, the temperature reached by the sample during the flux jump at different magnetic fields is calculated. 相似文献
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In this paper we consider robust stabilization of the class of nonlinear plants of the form $$\dot x = f(x) + \sum\limits_{i = 1}^m {g_i } (x)u_i (t),$$ which are equivalent, under smooth state space coordinate transformations and nonlinear state feedback, to controllable systems. This approach is very sensitive for unknown parameters' values. Parameter adaptation may be used as a technique to robustify minimum-phase systems [3]. We give an example of a locally stable adaptive tracking system in which the last assumption is weakened. The minimum-phase plant considered in the paper is a current-controlled squirrel cage induction motor. 相似文献
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Paweł Piszcz Magdalena Woźniak Monika Asztemborska Bronisław K. Głód 《Food Analytical Methods》2014,7(7):1474-1480
The present investigation reports on the application of a new antioxidant activity assay for the examination of flavonoids. It has been shown that the high-performance liquid chromatography with electrochemical detection (HPLC–ED) measurements allow to obtain additional information about the antioxidative properties of pure compounds by measuring their half-wave potential, the chromatographic peak height, and the product of the peak height and exponent of potential. In comparison to the classical electrochemical measurements, the HPLC–ED is characterized by a much smaller detection limit. The results were compared with the standard photometric measurement based on 1,1-diphenyl-2-picrylhydrazyl radicals. The possible antioxidant activity forecasting is also discussed. 相似文献
10.
Maj Justyna Węglewski Witold Bochenek Kamil Rogal Łukasz Woźniacka Stefania Basista Michał 《Metallurgical and Materials Transactions A》2021,52(11):4727-4736
Squeeze casting and powder metallurgy techniques were employed to fabricate AlSi12/Al2O3 composites, which are lightweight structural materials with potential applications in the automotive industry. The impact of the processing route on the material properties was studied. Comparative analyses were conducted for the Vickers hardness, flexural strength, fracture toughness, thermal conductivity, thermal residual stresses, and frictional wear. Our results show that the squeeze cast composite exhibits superior properties to those obtained using powder metallurgy.
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