The widespread application of thermophotovoltaic (TPV) cells has been significantly limited by their low energy conversion efficiency. This study aims to explore the factors and mechanisms influencing the energy conve...
The widespread application of thermophotovoltaic (TPV) cells has been significantly limited by their low energy conversion efficiency. This study aims to explore the factors and mechanisms influencing the energy conversion efficiency of TPV cells. A temperature-controllable high quasi-monochromatic thermal radiation testing platform was constructed. The controlled variable method was used to study the effects of different spot positions, cell temperatures, radiation energy flux densities, and beam sizes on the energy conversion performance of TPV cells. Meanwhile, a two-dimensional finite element model of the surface current flow was developed based on the SEM of the TPV cell. The experimental results were further explained using the simulation results. The results showed that when other conditions remained constant, the performance of the cell was not affected by the position of the light spot. For each 1℃ increase in temperature, the current rose by approximately 0.5 mA, while the V oc decreased by approximately 2 mV. When the incident radiation energy flux increased, the output current rose, while the V oc initially increased and then decreased. When other conditions remained constant, as the beam size increased, the I sc remained unchanged, the V oc decreased, and the output power increased. Therefore, an optimal operating environment should be selected to maximize TPV cell performance.
Mechanical agitation in baffled vessels with turbines plays a vital role in achieving homogeneous fluid mixing and promoting various transfer ***,designing vessels with optimal energy efficiency and flow dynamics is e...
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Mechanical agitation in baffled vessels with turbines plays a vital role in achieving homogeneous fluid mixing and promoting various transfer ***,designing vessels with optimal energy efficiency and flow dynamics is essential to enhance operational performance and eliminate flow ***,the present research focuses on a numerical investigation of the impact of inclined slots with different angles installed at the side-wall of a cylindrical vessel equipped with a Rushton *** study explores power consumption and vortex size while considering various rotation directions of the impeller with different rotation *** numerical simulations are conducted for Reynolds numbers ranging from 104 to 105,using the RANS k-εturbulence model to govern the flow inside the stirred vessel,accounting for mass and momentum *** results have shown that the installation of slots reduces power consumption and vortex size compared to conventional vessel ***,increasing the slot angle from 0 to 32.5°further reduces energy consumption and vortex size,especially with negative rotation *** the other hand,increasing the Reynolds numbers leads to a decrease in power consumption and an increase in vortex *** present research therefore proposes a design for con-structing Rushton-turbine stirred vessels offering optimal operation,characterized by reduced energy consumption and minimized vortex size.
Graph convolutional networks (GCNs), which are capable of effectively processing graph-structural data, have been successfully applied in text classification task. Existing studies on GCN based text classification mod...
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We address the cryptographic topic of proxy re-encryption （PRE）, which is a special public-key cryptosystem. A PRE scheme allows a special entity, known as the proxy, to transform a message encrypted with the public...
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We address the cryptographic topic of proxy re-encryption （PRE）, which is a special public-key cryptosystem. A PRE scheme allows a special entity, known as the proxy, to transform a message encrypted with the public key of a delegator （say Alice）, into a new ciphertext that is protected under the public key of a delegatee （say Bob）, and thus the same message can then be recovered with Bob＇s private key. In this paper, in the identity-based setting, we first investigate the relationship between so called mediated encryption and unidirectional PRE. We provide a general framework which converts any secure identity-based unidirectional PRE scheme into a secure identity-based mediated encryption scheme, and vice versa. Concerning the security for unidirectional PRE schemes, Ateniese et al. previously suggested an important property known as the master secret security, which requires that the coalition of the proxy and Bob cannot expose Alice＇s private key. In this paper, we extend the notion to the identity-based setting, and present an identity-based unidirectional PRE scheme, which not only is provably secure against the chosen eiphertext attack in the standard model but also achieves the master secret security at the same time.
We attempt to give a historical account of the main ideas leading to the development of nonlinear filtering and stochastic control as we know it today. We present a development of linear filtering theory, beginning wi...
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We attempt to give a historical account of the main ideas leading to the development of nonlinear filtering and stochastic control as we know it today. We present a development of linear filtering theory, beginning with Wiener-Kolmogoroff filtering and ending with Kalman filtering. The linear-quadratic-Gaussian problem of stochastic control is considered and states that for this problem the optimal stochastic control can be constructed by solving separately a state estimation problem and a deterministic optimal control problem. Many of the ideas presented here generalize to the nonlinear situation. A reasonably detailed discussion of nonlinear filtering, again from the innovations viewpoint, is given. Finally, we deal with optimal stochastic control. The general method of discussing these problems is dynamic programming.
Although using the microstructure of a surface to enhance specific functions has immense applicability in numerous fields,few studies have been conducted on the multi-functional properties of nuclear fuel elements in ...
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Although using the microstructure of a surface to enhance specific functions has immense applicability in numerous fields,few studies have been conducted on the multi-functional properties of nuclear fuel elements in harsh *** this study,surfaces with zirconium alloy micro-pillar arrays were prepared using micro-milling and ultraviolet nanosecond laser technology,and their functional properties such as the wettability,structural stability,and corrosion resistance were *** was found that the geometric dimension of the micro-pillar arrays prepared using these two methods could meet the design requirements,but the micro-milling process had the best dimensional ***-nano multi-scale structures were obtained by laser ***,these multi-scale structures exhibited weak structural stability,and the nanostructures were easily *** contrast,the micro-pillar arrays manufactured using micro-milling were confirmed to have better structural stability and corrosion *** one hand,the area mass loss of the micro-milled structure was lower than that of a flat surface after experiencing high-pressure fluid scouring at 8 and 38 m/*** the other hand,the oxidation weight gain of the surface with the micro-milled structure was lower than that of a flat surface,and the oxide film was 22.5% thinner after 100 days of deionized water corrosion at 360℃ and 18.7 MPa.
The use of high-permittivity(high-k) thin films as gate dielectrics is essential in the development of lowpower electronics,In this work,rare-earth thulium oxide(Tm_(2)O_(3)) thin films were prepared by a facile solut...
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The use of high-permittivity(high-k) thin films as gate dielectrics is essential in the development of lowpower electronics,In this work,rare-earth thulium oxide(Tm_(2)O_(3)) thin films were prepared by a facile solution process and annealed at various temperatures from 400 to 700℃.The evolution of the physical and dielectric properties of Tm_(2)O_(3) thin film with annealing temperature was *** is demonstrated that the Tm_(2)O_(3) thin film annealed at 600℃ exhibits the optimal performance,including a low leakage current of 3×10^(-10) A/cm^(2),a large areal capacitance of 250 nF/cm^(2) at 100 Hz,and a high permittivity value of *** Tm_(2)O_(3) thin film as a gate insulator was integrated into the thin film transistor(TFT) employing In_(2)O_(3)-based semiconducting *** In_(2)O_(3) TFT with 600℃-annealed Tm_(2)O_(3) dielectric exhibits the superior perfo rmance,with a high I_(on)/I_(off) of 1.65×10^(7),a small subthre shold swing(SS) value of 0.2 V/dec,a V_(TH) of+1.8 V,and a mobility of 1.68 cm^(2)/(V·s).Furthermore,an inverter constructed by connecting the TFT with a resistor exhibits full-swing *** work provides a facile and appealing method for preparing the high-k Tm_(2)O_(3) thin films as alternative gate dielectrics with the potential for use in low-power electronics and logic circuit applications.
The influences of phase and group velocity matching on cumulative second harmonic generation of Lamb waves are investigated in numerical perspective. Finite element simulations of nonlinear Lamb wave propagation are p...
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The influences of phase and group velocity matching on cumulative second harmonic generation of Lamb waves are investigated in numerical perspective. Finite element simulations of nonlinear Lamb wave propagation are performed for Lamb wave mode pairs with exact and approximate phase velocity matching, with and without group velocity matching, respectively. The evolution of time-domain second harmonic Lamb waves is analyzed with the propagation distance. The amplitudes of primary and second harmonic waves are calculated to characterize the acoustic nonlinearity. The results verify that phase velocity matching is necessary for generation of the cumulative second harmonic Lamb wave in numerical perspective, while group velocity matching is demonstrated to not be a necessary condition.
While the wave packet of a massive particle grows linearly under free dynamics, it grows exponentially in an inverted harmonic potential, offering a pathway to rapidly increase quantum fluctuations to macroscopic dime...
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This paper considers the simultaneous attack problem of multiple missiles against a maneuvering target. Different from most of the existing literature in which the simultaneous attack problem is formulated as a consen...
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This paper considers the simultaneous attack problem of multiple missiles against a maneuvering target. Different from most of the existing literature in which the simultaneous attack problem is formulated as a consensus problem of missiles＇ time-to-go estimates, this paper formulates it as the consensus problem of missiles＇ ranges-to-go. Based on this strategy, novel distributed guidance laws are proposed to solve the simultaneous attack problem with the target of unknown *** control method is introduced to estimate the upper bound of the target＇s acceleration. The effectiveness of the proposed guidance laws is verified both theoretically and numerically.
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