Nanosilicon for single-electron devices

The optimization of structural parameters of controllable reactor of transformer type (CRT) is of great significance for improving its economic benefits. This paper takes the new-type magnetic integration structure CRT as the research object. Qualitative analysis is employed to explore the relationship between loss, cost and structural parameters of CRT. The optimization model of structural parameters is established with the objective of minimizing cost and loss. The genetic algorithm is used to optimize the structural parameters of CRT. Based on this, a new economic calculation method of CRT's structural parameters is proposed. The results show that the optimization of CRT's structural parameters aiming at minimizing cost and loss is essentially to optimize the cross-sectional area of iron core and the length of winding coil. A new method for calculating CRT's structural parameters based on genetic algorithm optimization has more reasonable calculation results. With the increase of CRT operating time, the proportion of CRT use costs caused by loss will gradually increase. The methods and conclusions used in this paper provide some theoretical guidance for the structural design and optimization of CRT.

In order to optimize the stope structure parameters in broken rock conditions, a novel method for the optimization of stope structure parameters is described. The method is based on the field investigation, laboratory tests and numerical simulation. The grey relational analysis (GRA) is applied to the optimization of the stope structure parameters in broken rock conditions with multiple performance characteristics. The influencing factors include stope height, pillar diameter, pillar spacing and pillar array pitch, the performance characteristics include maximum tensile strength, maximum compressive strength and ore recovery rate. The setting of influencing factors is accomplished using the four factors four levels Taguchi experiment design method, and 16 experiments are done by numerical simulation. Analysis of the grey relational grade indicates the first effect value of 0.219 is the pillar array pitch. In addition, the optimal stope structure parameters are as follows: the height of the stope is 3.5 m, the pillar diameter is 3.5 m, the pillar spacing is 3 m and the pillar array pitch is 5 m. In-situ measurement shows that all of the pillars can basically remain stable, ore recovery rate can be ensured to be more than 82%. This study indicates that the GRA method can efficiently applied to the optimization of stope structure parameters.

A molecular-dynamics technique is applied to single-electron charging effects in semiconductor wires, and the impact of strong electron-electron correlation on the conductance is investigated. Because of the relatively low electron density in semiconductors compared to a metal, the screening length is comparable to the sample size, which requires a treatment beyond the conventional Coulomb-blockade argument using macroscopic capacitance. Based on the molecular-dynamics method, most features of the periodic conductance oscillation in the double-barrier system are reproduced, and the feasibility of this technique in single-electron charging phenomena is demonstrated. Experimental observation of an activation energy smaller than the threshold energy of the nonlinear conductance, which the normal Coulomb-blockade model cannot explain, is reproduced in the present approach. This effect is due to the strong microscopic correlation, so that this is essential to describe accurately the single-electron charging effects in semiconductor systems.

A quasi 2-D conduction model based on the thermionic emission of charge carriers over the energy barriers at discrete grain boundaries is formulated for a polycrystalline silicon thin-film transistor with an undoped body. Each grain boundary is characterized by an energy-dispersed density of trap states. The occupied trap states are assumed to form a ldquolinerdquo charge adjacent to the interface of the channel and the gate dielectric of a transistor. The electrostatic potential of a grain boundary is subsequently determined. This general approach allows the modeling of energy barriers in a transistor without deliberate channel doping, and the resulting conduction model is continuously applicable from the ldquopseudosubthresholdrdquo to the ldquolinearrdquo regime of operation of a transistor. Good agreement between the experimental and the calculated transfer and output characteristics is obtained. The procedure for determining the density of trap states is described and demonstrated. It is found that the energy dependence of the trap states can be approximated by a simple exponential function.

The integration of redundant structures into robotic systems enhances the degrees of freedom (DOFs), flexibility, and capability to perform complex tasks. This study evaluates the mechanical performance of a 9-DOF series-parallel hybrid redundant device designed for rehabilitation training of patients with balance disorders. The redundant structural design improves the robot's movement flexibility, optimizes load distribution, and mitigates stress concentration in local joints or components. To optimize the robot's overall structural parameters and reduce joint driving forces, a genetic algorithm (GA) was employed. A custom dataset was created by collecting motion-related data, including foot posture and position. The robot's mechanical characteristics were comprehensively analyzed, followed by simulation experiments. The results demonstrate that incorporating the redundant structure, along with the optimization of structural parameters, significantly enhances the robot's mechanical performance. This study provides a solid foundation for the functional development and control system design of rehabilitation robots, extending the capabilities of existing systems and offering a novel, reliable, and efficient therapeutic tool for patients with balance disorders.

The use of a combination of tunneling and optical spectroscopy to investigate the size and shape-dependent level structure and single-electron charging phenomena in semiconductor nanocrystals is reviewed. The artificial atom character of semiconductor nanocrystal quantum dots is manifested in both the discrete level structure and in the charging multiplicity of the single-electron tunneling data, revealing s and p atomic-like states. Such states can be directly imaged using scanning tunneling microscopy, providing the extent and symmetry of the envelope wavefunctions. A detailed description of the effect of the tunneling geometry on the single-electron tunneling spectra is presented. Correlation of the optical and tunneling data allows for the assignment of the level spectrum. The generality of this powerful combination is further demonstrated in the study of quantum rods that manifest the transition from zero-dimensional quantum dots to one-dimensional quantum wires.

Thermomechanical pretreatment of Al-Zr-Mg-Cr alloy to improve the performance through creep-age forming

Transport properties of a Si quantum dot at 4.2 K have been studied. A quantum dot is realized in the inversion layer of a Si metal-oxide-semiconductor field-effect-transistor (Si-MOSFET) with a dual-gate structure by introducing controllable tunnel barriers in the narrow channel. Periodic current oscillations due to the single-electron charging effect have been observed. With increasing tunnel barrier heights, Coulomb gaps appear in the I-V characteristics. Furthermore, leakage current in the Coulomb blockade regime varies linearly with bias voltage, which is quantitatively described in terms of the inelastic co-tunneling theory at finite temperatures.

Vortex beams (VBs) generated by plasmonic metasurfaces hold great potential in the field of information transmission due to their unique helical phase wavefronts and infinite eigenstates. However, achieving perfect multiplexing and superposition of VBs with different orders remains a challenging issue in nanophotonics research. In this paper, based on a single-layer metallic porous metasurface structure applicable to the infrared spectrum, VBs with orders 2, 4, 6, and 8 are realized through the arrangement of annular elliptical apertures. Moreover, perfect VBs are achieved by optimizing key structural parameters using a genetic algorithm. The optimization of key structural parameters via genetic-based optimization algorithms to attain the desired effects can significantly reduce the workload of manual parameter adjustment. In addition, leveraging the orthogonality between VBs of different orders, concentric circular multi-channel VBs array (l = 2, 6) and (l = 4, 8) are realized. High-purity multiplexing architectures (>90%) are achieved via rational optimization of critical structural parameters using a genetic optimization algorithm, which further mitigates information crosstalk in optical communication transmission. The introduction of the genetic algorithm not only reduces the workload of manual arrangement of unit arrays but also enables the generation of more perfect VBs, providing a new research direction for optical communication transmission and optical communication encryption.

Optimization of UNIQUAC structural parameters for individual mixtures; application to new experimental liquid-liquid equilibrium data for aqueous solutions of methanol and ethanol with isoamyl acetate

The composite structure of a microperforated panel and porous metal is a promising sound absorber for industrial noise reduction, sound absorption performance of which can be improved through parameter optimization. A theoretical model is constructed for the composite structure of a microperforated panel and porous metal based on Maa’s theory and the Johnson–Champoux–Allard model. When the limited total thickness is 30 mm, 50 mm, and 100 mm respectively, dimensional optimization of structural parameters of the proposed composite structure is conducted for the optimal average sound absorption coefficient in the frequency range (2000 Hz, 6000 Hz) through a cuckoo search algorithm. Simulation models of the composite structures with optimal structural parameters are constructed based on the finite element method. Validations of the optimal composite structures are conducted based on the standing wave tube method. Comparative analysis of the theoretical data, simulation data, and experimental data validates feasibility and effectiveness of the parameter optimization. The optimal sandwich structure with an actual total thickness of 36.8 mm can obtain the average sound absorption coefficient of 97.65% in the frequency range (2000 Hz, 6000 Hz), which is favorable to promote practical application of the composite structures in the fields of sound absorption and noise reduction.

Hybrid electric vehicles (HEVs) are equipped with multiple power sources and involve complex mode-switching processes, which lead to intricate torsional vibration characteristics in their powertrains. This paper presents a novel clutch torsional damper with arc springs (CTD-AS) that combines the advantages of traditional clutch torsional dampers (CTDs) and dual-mass flywheels (DMFs). The structure and working principle of the CTD-AS are introduced in the paper, and a torsional damper parameter design method is discussed. During the study, a 13-degree-of-freedom concentrated mass model was established for an HEV powertrain, and optimization schemes based on multiple sets of operating conditions were obtained for a CTD, a DMF, and the CTD-AS. The optimized simulation results demonstrated that the average torsional vibration transmissibility value of the CTD-AS under the three working conditions was approximately 13.8% and 29.7% lower than that of the DMF and the CTD, respectively, and the overall performance is the best. The novel structural topology and parameter optimization method for the torsional damper of a parallel HEV proposed in this paper can effectively enhance driving smoothness under a variety of working conditions.

An automatic design system for the voltage reference circuit is presented in this paper. The circuit coding method based on tracking coding is improved and the instruction set is expanded, thus the circuit structure with MOS transistors can be automatically generated. The differential evolution method is used to optimize the reference circuit. To improve the convergence speed and optimization effect, a new constrained solution and a fast non-dominated differential evolution algorithm based on weights are proposed. At the same time, HashMap is used as the cache to reduce the optimization time. Based on the proposed automatic structure generation and parameter optimization, two CMOS voltage reference circuits are automatically implemented in a 0.18 μm standard CMOS process. Simulation results show that the line sensitivity, temperature coefficient, power and chip area are improved by 85.7%, 50%,92.7% and 59.5%, respectively, compared with the artificial solution.

Describes an approach to automatically build a Takagi-Sugeno fuzzy model (TSK-model) based on a set of input-output data. Identifying rule-based fuzzy models consists of two parts: structure modeling and parameter optimization. For structure modeling, we investigate several search heuristics. In order to find a good model structure, such search heuristics make it necessary to optimize and then evaluate a large number of different candidate models. To be applicable to real world problems, the parameter optimization must be highly efficient. For this, we investigate the use of two gradient descent algorithms: standard gradient descent (backpropagation) and resilient propagation (RPROP). The combination of a structure search with a fast parameter optimization yields a powerful modeling algorithm that is capable to identify large real world systems. We evaluate a number of varieties of TSK-like fuzzy models by performing a nonlinear regression benchmark of Frank (1995). We compare several types of fuzzy models that are constructed as combinations of different fuzzy sets, structuring algorithms, and parameter optimization techniques.

Passive walkers perform a walking like stable limit cycle on small slopes without any external control. In this research, a deployed model of biped that can be built has been considered, and then its walking performance sensitivity such as efficiency, stability and robustness on uneven trains due to variation of structural parameters and their optimum limits have been investigated. It was shown that the foot arc radius and center of mass height have the most important effect on walking performance. After doing simulations in MSC.ADAMS software, an optimum design trend has been suggested. At the end based on experimental results, it was shown beside optimization of structural parameters, the impact condition is very important to achieve optimal walking.