Modern differential scanning calorimeter (DSC) is a complex information-measuring system used to obtain different temperature and thermal characteristics of the investigated substances. The main subsystem of DSC is a ...
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ISBN:
(纸本)9781728167008
Modern differential scanning calorimeter (DSC) is a complex information-measuring system used to obtain different temperature and thermal characteristics of the investigated substances. The main subsystem of DSC is a heat block including heaters, measuring cells, and heat conducting elements. Measuring cells in the thermal block are often located symmetrically in relation to the center. However, the heat flow coming from the main heater affects them unevenly. At different overall parameters of reference and test substances uneven cells heating leads to measurement error increase. Since the defining of thermal characteristics of materials using DSC is carried out in a dynamic mode it is necessary to take into account not only the dependence of measuring cell parameters on time, but also the spatial distribution of the external thermal impact affecting it. Measuring cell DSC mathematical model is given as a block with a distributed input and concentrated output effect. The model takes into account the uneven spatial distribution of the thermal field in the thermal block, as well as heat removal from the substrate through the sensing elements considered to be inertial links. A structural model of the heat flow control system in a heat block DSC was constructed on the basis of the measurement cell mathematical model. The model shows the following: basic elements and their relationships, radiation influence on heat flow formation reaching the measuring cell and additional heat formation from micro aggregates, its influence on the measuring cell. After a number of experiments, a computer model of the automatic heat flow control system in the measuring cell of the differential scanning calorimeter DSC-500 was built as a control object with distributed parameters. This model serves as the basis for numerical experiments required to adjust the regulators parameters of the main and additional heaters in the thermal block of the DSC at different modes of this information-measu
The paper considers the stability analysis of the surge tank in hydroelectric power plants, in the case of elastic upstream water column i.e. with distributed parameters tunnel. The model is obtained as a special case...
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ISBN:
(数字)9781665467469
ISBN:
(纸本)9781665467469
The paper considers the stability analysis of the surge tank in hydroelectric power plants, in the case of elastic upstream water column i.e. with distributed parameters tunnel. The model is obtained as a special case from a rather general hydroelectric plant structure with distributed parameters of the water flow along the conduits. The stability of the linearized model is discussed using the stability of an associated system of neutral functional differential equations via the classical results on Hurwitz quasi-polynomials obtained by N. G. Cebotarev and N. N. Meyman. Application of these results leads to an improved Thoma inequality containing a safety factor larger than 1.
A boundary integral equation (BIE) method for extracting distributed parameters of coupled interconnects is proposed in this paper. With the equivalent principle, the electric field on the boundary is correlated with ...
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ISBN:
(纸本)9780996007894
A boundary integral equation (BIE) method for extracting distributed parameters of coupled interconnects is proposed in this paper. With the equivalent principle, the electric field on the boundary is correlated with surface current through a contour integration. The adaptive cross approximation technique is employed to accelerate the solving procedure. The validity and accuracy of the proposed method are demonstrated by the numerical results.
Large dv/dt and di/dt due to power device fast switching within a DC-fed voltage-type PWM inverter of high power density and high-efficiency motor drive system for electric vehicle (EV) always introduce unwanted high ...
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ISBN:
(纸本)9781509015467
Large dv/dt and di/dt due to power device fast switching within a DC-fed voltage-type PWM inverter of high power density and high-efficiency motor drive system for electric vehicle (EV) always introduce unwanted high frequency noise current through parasitics/distributed parameters of the motor drive system. The complete test setup for conducted-EMI emission from the AC motor drive system of EV are built to measure the conducted voltage of DC cables. The CM EMI current paths at resonance frequencies 500KHz and 30MHz are analyzed based on the distribution parameters. The CM current equivalent circuits for 500 kHz and 30MHz are presented. The dominated elements responsible for the appearing resonances at 500 kHz and 30MHz in measurement results are determined. A mitigation conducted-EMI emission strategy based on distributed parameters of power inverter system in EV is proposed. Simulation and measurement are used to validate the mitigation mothed.
In a system with substantially distributed parameters the state vector q represents a distribution density function over some parameter z: q = q(z,t). Derivatives exist only with respect to time t, whereas in spatiall...
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In the paper a literature review concerning development and application of mathematical models for the analysis of transient states of complex electro-mechanical systems with distributed parameters is presented. Speci...
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ISBN:
(纸本)9781479937219
In the paper a literature review concerning development and application of mathematical models for the analysis of transient states of complex electro-mechanical systems with distributed parameters is presented. Special attention is paid to real-life systems and to presentation of results of digital simulations. In the paper the assumptions for the analysis of transient states of complex electro-mechanical systems in the context of occurrence of vibrations in the rotation transmission system. A general form of the mathematical model for the analysis of transient states of electro-mechanical systems is given, which makes it possible to describe in the continuous form the system of rotation transmission for any of its components. The final form of the equations of the mathematical model, which makes it possible to carry out the digital simulations and to obtain the results as 3D planes that depict the vibrations in reference to time and to real fragments of rotation transmission chain for chosen quantities under examination, is presented.
The main objective of this work is to quantitatively study the extraction problem of distributed parameters of unparallel transmission lines, especially for one specific type of unparallel transmission line model. The...
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ISBN:
(纸本)9781479952748
The main objective of this work is to quantitatively study the extraction problem of distributed parameters of unparallel transmission lines, especially for one specific type of unparallel transmission line model. The infinitesimal transmission lines are equivalent to the parallel transmission lines, and the estimation method of distributed parameters is presented based on the original physical definition of distributed parameters. Numerical experiments show that distributed parameters are related to axial variable and the angle of wires, it represents the nonuniform characteristic of parameters;when the angle of the wires is close to zero, the distributed parameters are the same as the parameters of parallel transmission lines, which validates the effectiveness of the method.
In this work are investigated the properties of the wave solutions of reaction-diffusion system with double nonlinearity. The influence of the parameters is investigated of the reaction-diffusion system in the evoluti...
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Land surface hydrologic models adeptly capture crucial terrestrial processes with a high level of spatial detail. Typically, these models incorporate numerous uncertain, spatially varying parameters, the specification...
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Land surface hydrologic models adeptly capture crucial terrestrial processes with a high level of spatial detail. Typically, these models incorporate numerous uncertain, spatially varying parameters, the specification of which can profoundly impact the simulation capabilities. There is a longstanding tradition wherein parameter calibration has served as the conventional procedure to enhance model performance. However, calibrating distributed land surface hydrologic models presents a great challenge, often resulting in uneven spatial performance due to the compression of information inherent in model outputs and observations into a single-value objective function. To address this problem, we propose a novel Generative Adversarial Network-based Parameter Optimization (GAN-PO) method. By leveraging a deep neural network to discern model spatial biases, we train a generative network to produce spatially coherent parameter fields, minimizing distinctions between simulations and observations. By leveraging neural network-based surrogate models to make the physical model differentiable, we employ GAN-PO to calibrate the Variable Infiltration Capacity (VIC) model against evapotranspiration (ET) over China's Huaihe basin. The results show that GAN-PO can diminish errors in simulated ET derived from default parameters across nearly all grid cells within the study region, surpassing the conventional calibration approach based on the parameter regionalization technique. Ablation analysis indicates that relying solely on the traditional loss could lead to deteriorated model performance, underscoring the crucial role of the discriminator. Notably, due to the discriminator's explicit identification of model spatial biases, GAN-PO excels in maintaining spatial consistency, outperforming the state-of-the-art differentiable parameter learning (dPL) method in terms of model spatial performance. A novel generative adversarial network-based parameter estimation method is proposed to cal
The amplitude-frequency characteristics play an essential role in analyzing transmission power grids, such as harmonic amplification using the amplitude-frequency characteristics as the harmonic amplification factor, ...
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The amplitude-frequency characteristics play an essential role in analyzing transmission power grids, such as harmonic amplification using the amplitude-frequency characteristics as the harmonic amplification factor, harmonic resonance, etc. However, when the cable line with distributed parameters is connected to powers, the model would be troublesome to be calculated for the amplitude-frequency characteristics by the existing methods. To fill this gap, we proposed a method of variable covariance probabilistic data association (PDA) Kalman filtering deconvolution. First, a typical high-voltage cable transmission system (HVCTS) and its dynamic model are established. Next, a square wave impulse excitation (SWIR) is injected into the system, and the square wave impulse response is extracted at the measurement ports. Then the variable covariance PDA Kalman filter (VCPDAKF) algorithm is proposed to denoise the noisy square wave impulse response. Meanwhile, the deconvolution method is used to obtain the amplitude-frequency characteristics based on the convolution model. Finally, it is verified through simulation and experiment that the VCPDAKF algorithm could effectively denoise the noisy square wave impulse response. The effectiveness of the proposed method for the amplitude-frequency characteristics is verified.
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