http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Effects of rapid thermal annealing on the optical properties of strain-free quantum ring solar cells
Wu, Jiang,Wang, Zhiming M,Dorogan, Vitaliy G,Li, Shibin,Lee, Jihoon,Mazur, Yuriy I,Kim, Eun Soo,Salamo, Gregory J Springer 2013 Nanoscale research letters Vol.8 No.1
<P>Strain-free GaAs/Al<SUB>0.33</SUB>Ga<SUB>0.67</SUB>As quantum rings are fabricated by droplet epitaxy. Both photoresponse and photoluminescence spectra confirm optical transitions in quantum rings, suggesting that droplet epitaxial nanomaterials are applicable to intermediate band solar cells. The effects of post-growth annealing on the quantum ring solar cells are investigated, and the optical properties of the solar cells with and without thermal treatment are characterized by photoluminescence technique. Rapid thermal annealing treatment has resulted in the significant improvement of material quality, which can be served as a standard process for quantum structure solar cells grown by droplet epitaxy.</P>
Effects of the Frequency-degree Correlation on Local Synchronization in Complex Networks
Shijin Jiang,Wenyi Fang,Shaoting Tang,Sen Pei,Shu Yan,Zhiming Zheng 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.2
We investigate the effects of the frequency-degree correlation on local synchronization in complex networks with Kuramoto oscillators. We find that a discontinuous synchronization transition occurs in the local patterns for heterogenous networks while for homogenous networks, the local synchronization transition remains continuous. Then, we extend our study to a general frequency-degree correlation case and conclude that the positive correlation does not change the local synchronization patterns while in the case of a negative correlation, the local synchronization transition degenerates to second order. Moreover, the correlation parameter α is verified to have a strong influence on the synchronization level. In particular, smaller |α| results in higher synchronization ability and faster speed to a synchronized state. Our study provides a deeper understanding of the effects of the frequency-degree correlation on network synchronization.
Effect of Externality in Multiplex Networks on One-layer Synchronization
Xin Jiang,Meng Li,Zhiming Zheng,Yifang Ma,Lili Ma 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.11
Synchronization phenomenon plays an important role in the dynamic process on complex networks. In this letter, we consider synchronization under multiplex structures and explore the effect of external parts on the multilayered Kuramoto model with positive correlation between frequencies and degree. We show that large and strong mixing parts of the external layer may put off synchronization while the coupling strength of external layers has an accelerating, but limited, influence on synchronization. In particular, an explosive synchronization can be obtained by weakening the co-evolution coupling strength. The transition tends to be smooth when the co-evolution coupling strength increases. Our findings indicate that externality from multiplex networks, especially the mixing parts, and the co-evolution coupling strength should be of importance for synchronization on one certain layer.
Hu Yifei,Jiang Xin,Huo Guanying,Su Cheng,Zhou Shiwei,Wang Bolun,Li Hexiong,Zheng Zhiming 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.1
Feed rate scheduling is a critical step in computer numerical control machining, as it has a close relationship with machining time and surface quality. It has now become a hot issue in both industry and academia. In this article, we present a novel and complete S-shape-based feed rate scheduling method for three-axis non-uniform rational B-spline (NURBS) tool paths, which can reduce high chord errors and round-off errors, and generate continuous velocity, acceleration, and jerk profile. The proposed feed rate scheduling method consists of three modules: a bidirectional scanning module, a velocity scheduling module, and a round-off error elimination module. The bidirectional scanning module aims to guarantee the continuity of the feed rate at the junctions between successive NURBS blocks, where the chord error, tangential acceleration, and tangential jerk limitations are considered. After the NURBS blocks have been classified into two cases by the previous module, the velocity scheduling module first calculates the actual maximum feed rate. It then generates the feed rate profiles of all NURBS blocks according to the proposed velocity profile. Later, the round-off error elimination module is applied to adjust the actual maximum feed rate so that the total interpolation time becomes an integer multiple of the interpolation period, which leads to the elimination of round-off errors. Finally, benchmarks are conducted to verify the applicability of the proposed method. Compared with the traditional method, the proposed method can save the interpolation time by $4.67$ to $14.26\% $.
Xinrong Chen,Zhiming Xu,Dingfa Fu,Hui Zhang,Jie Teng,Fulin Jiang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.6
Hot compression tests were conducted on Al–Si/SiCp + TiB2 hybrid aluminium matrix composites with various TiB2contentsat temperatures from 350 to 500 °C and strain rates from 0.001 to 1 s−1. The hot workability characteristics and deformationmechanisms were investigated by combining constitutive equations, processing maps and microstructural observationsthrough scanning electron microscopy and transmission electron microscopy measurements. The results showed that therewere small differences in the peak stresses when the contents of TiB2were 3% and 5%, while the peak stress increased whenthe content of TiB2reached 8%. The contents of TiB2had little influence on the activation energy but affected the processingmaps to a certain extent. The areas of the instability zones were observed to gradually increase with increased TiB2additions. The optimal deformation conditions of the studied materials migrated from a low temperature and high strain rate to a hightemperature and low strain rate with increasing TiB2content. In addition, the flow softening mechanism transformed fromdynamic recrystallization + dynamic recovery to dynamic recovery with increasing TiB2content.
CNC tool path generation for freeform surface machining based on preferred feed direction field
Guanying Huo,Xin Jiang,Cheng Su,Zehong Lu,Yuwen Sun,Zhiming Zheng,Deyi Xue 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.5
This paper presents a novel method to generate three-axis CNC tool paths for machining freeform surfaces based on a preferred feed direction field. This research was initiated from a fluid dynamics behavior that the energy loss can be reduced when the streamlines of fluid and the small grooves on a surface are in the same directions. In this research, the fluid streamlines above the surface are defined by a collection of vectors. These vectors are regularized into a grid of vectors, and these regularized vectors are further projected onto the tangent planes of a grid of points on the surface to create the preferred feed direction field. Based on the parametric model of the surface, the vectors on the tangent planes of the surface are mapped into vectors in the parametric domain. A scalar function is constructed such that the isolines of this scalar function and the preferred feed direction vectors in the parametric domain are in the same directions. A group of isolines of the scalar function are identified and these isolines are mapped back onto the 3-D surface as the created tool paths considering the tolerance requirement. The developed method has been applied to generate the tool paths for machining surfaces of a compressor blade.
Li Hu,Shuyong Jiang,Jian Tu,Zhiming Zhou 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.2
The subgrain effect of NiTi shape memory alloy during canning compression at 400 °C is investigated through electronback-scattered diffraction (EBSD) experiment, transmission electron microscope (TEM) experiment and crystal plasticityfinite element (CPFE) simulation in explicit consideration of subgrain within each grain. Experimental investigations basedon TEM and EBSD measurements confirm that the formation of subgrain actually results from the dislocation motion duringcanning compression. Numerical simulations based on the constructed polycrystalline models with various subgrains areused to investigate the subgrain effect during canning compression from a different point of view. In terms of texture evolution,subgrain effect does not change the tendency of texture evolution, but it contributes to the dispersed distribution withrespect to the deformed grain/subgrain orientations. As for accumulative shear strain, subgrain effect contributes to sustaininglarger plastic strain inside each grain, and it also results in the strain concentration near grain boundaries. With respectto von Mises stress, the subgrain effect facilitates the ease of stress concentration near grain boundaries and it contributesto possessing a homogeneous stress distribution within the inner part of each grain.
Preparation of Highly Visible-Light Photocatalytic Active N-Doped TiO<sub>2</sub> Microcuboids
Zhao, Kang,Wu, Zhiming,Tang, Rong,Jiang, Yadong Korean Chemical Society 2013 대한화학회지 Vol.57 No.4
N-doped $TiO_2$ microcuboids were successfully prepared by a simple one-pot hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy, diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. It was found that the N-doped $TiO_2$ microcuboids enhanced absorption in the visible light region, and exhibited higher activity for photocatalytic degradation of model dyes. Based on the experimental results, a visible light induced photocatalytic mechanism was proposed for N-doped anatase $TiO_2$ microcuboids.