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Xu Zhang,Yuanming Xu,Shuming Zhang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.4
With the increased use of composite materials in aircraft main load-bearing structures, it is of great significance tostudy the failure modes and energy absorption characteristics of the structures made up of composite materials. This paperused finite element method (FEM) and investigated the performances of braided composite tubes with semi-circular cavityexternal trigger during crashing. The generated data were used to modify the dynamic Kriging model. Based on the surrogatemodel, the artificial bee colony (ABC) optimization algorithm was used to optimize the cavity radius, tube diameter and tubethickness, so as to minimize the peak load and maximize the specific energy absorption (SEA). The results showed that theKriging model had high accuracy and efficiency in simulating the stress and deformation. The proposed model determinedthe optimized parameters using the ABC model, one of which improved the SEA by 39.6 % and reduced the peak load by38.6 %, thereby improving the structural properties of braided composite materials.
Tong Liu,Rong Huang,Fangsen Li,Zengli Huang,Jian Zhang,Jianping Liu,Liqun Zhang,Shuming Zhang,An Dingsun,Hui Yang 한국물리학회 2018 Current Applied Physics Vol.18 No.7
The accuracy and error propagation for determining the low specific contact resistance of Ohmic contacts on IIIV wide band-gap semiconductors based on the circular transmission line model have been analyzed and the validity of this method is discussed in detail. The accuracy is more susceptible to the factors including data fitting method, electrical measurement technique and contact area correction. By using the equations of the original circular transmission line model to extract the fitting parameters, the calculation accuracy is much improved and the inapplicability of the linear least-square fitting is prevented. To further improve the accuracy, a four-probe current-voltage measurement technique was adopted to reduce the parasitic series resistances and the uncertainty bound, especially for the Ohmic contact with low sheet resistance of the semiconductor. Moreover, we have studied the size effect of contact pads of patterns and demonstrated that contact area correction is necessary for the semiconductor with high sheet resistance. A comprehensive error analysis is also performed to fully understand all the impact factors on this advanced method of specific contact resistance measurement, which is benefit for device performance evaluation and failure analysis.
Recent progress in the device architecture of white quantum-dot light-emitting diodes
Shuming Chen,Heng Zhang,Qiang Su 한국정보디스플레이학회 2019 Journal of information display Vol.20 No.4
White-light-emission quantum dot light-emitting diodes (WQLEDs) have attracted great attention of late because they could have potential applications in both flat-panel displays and solid-state lighting due to their advantages of tunable emission spectra, low driving voltage, high luminous efficiency, and high brightness. Over the past decades, with the rapid development of both quantum dot (QD) materials and device structures, WQLEDs have achieved tremendous progress. This review investigates the influence of device architectures on the performance of WQLEDs. The importance and status of the WQLEDs based on CdSe-QDs are first discussed. Then WQLEDs with a mixed-QD single light emission layer (EML), a multilayered QD EML, and tandem structures are reviewed. WQLEDs based on cadmium-free QDs are also briefly introduced. Finally, the key challenges that WQLEDs are currently facing are identified, and some possible solutions are proposed for further developing stable and efficient WQLEDs.
Fanyu Meng,Shuming Shi,Boshi Zhang,Yunxia Li,Nan Lin 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.6
As more and more researchers begin to analyse the dynamics characteristics of high-degree-of-freedom and nonlinear vehicle models, it is very important and valuable to propose a new analysis method for this type of model. Moreover, it is a promising research direction to propose quantitative indicators for analysing global vehicle dynamics. Therefore, on the basis of classic works, this paper proposes and verifies a quantitative analysis method - dissipation of energy method for 5-DOF nonlinear vehicle plane motion model for the first time. The quantitative indicators for vehicle nonlinear dynamics is expanded. The transfer relationship between the energy components is revealed, which shows that the dissipation of energy method can reflect the dynamics characteristics and stable region characteristics of the nonlinear 5-DOF vehicle system. The effects of tire force lateral-longitudinal coupling and driving modes on global dynamics are analysed. Finally, the prospect of this method is discussed.
Lianping Zhao,Ying Wang,Yanbin Jia,Shuming Zhong,Yao Sun,Zhifeng Zhou,Zhongping Zhang,Li Huang 대한신경정신의학회 2017 PSYCHIATRY INVESTIGATION Vol.14 No.4
Objective: Bipolar disorder (BD) is often misdiagnosed as unipolar depression (UD), leading to mistreatment and poor clinical outcomes. However, little is known about the similarities and differences in subcorticalgray matter regions between BD and UD. Methods: Thirty-five BD patients, 30 UD patients and 40 healthy controls underwent diffusional kurtosis imaging (DKI) and three dimensional arterial spin labeling (3D ASL). The parameters including mean kurtosis (MK), axial kurtosis (Ka), radial kurtosis (Kr), fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Da), radial diffusivity (Dr) and cerebral blood flow (CBF) were measured by using regions-of-interest analysis in the caudate, putamen and thalamus of the subcortical gray matter regions. Results: UD exhibited differences from controls for DKI measures and CBF in the left putamen and caudate. BD showed differences from controls for DKI measures in the left caudate. Additionally, BD showed lower Ka in right putamen, higher MD in right caudate compared with UD. Receiver operating characteristic analysis revealed the Kr of left caudate had the highest predictive power for distinguishing UD from controls. Conclusion: The two disorders may have overlaps in microstructural abnormality in basal ganglia. The change of caudate may serve as a potential biomarker for UD.
Yuanping Sun,Yuanping Sun,조용훈,Hui Wang,Lili Wang,Shuming Zhang,Hui Yang 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.1
InN nanostructures with and without GaN capping layers were grown by using metal-organic chemical vapor deposition. Morphological, structural, and optical properties were systematically studied by using atomic force microscopy, X-ray diffraction (XRD) and temperature-dependent photoluminescence (PL). XRD results show that an InGaN structure is formed for the sample with a GaN capping layer, which will reduce the quality and the IR PL emission of the InN. The lower emission peak at 0.7 eV was theoretically fitted and assigned as the band edge emission of InN. Temperature-dependent PL shows a good quantum efficiency for the sample without a GaN capping layers; this corresponds to a lower density of dislocations and a small activation energy.
Optical properties of InN rods on sapphire grown by metal–organic chemical vapor deposition
Sun, Yuanping,Cho, Yong-Hoon,Dai, Zhenhong,Wang, Weitian,Wang, Hui,Wang, Lili,Zhang, Shuming,Yang, Hui Elsevier 2010 Physica E, Low-dimensional systems & nanostructure Vol.43 No.1
<P><B>Abstract</B></P><P>The InN rods were grown by metal–organic chemical vapor deposition with a density of 1.4×10<SUP>9</SUP>cm<SUP>−2</SUP>. Optical properties of InN rods have been systematically investigated by means of temperature dependent photoluminescence (PL) and power dependent PL. Four peaks appear in the PL spectra and the origination was analyzed. The lowest energy peak P1 (0.665eV) is attributed to transitions of conduction band electrons to the photo-holes captured by deep acceptor; P2 (0.717eV) is the direct band-to-band transition peak of InN; main peak P3 (0.759eV) results from the recombination of degenerate electrons with photo-holes near the top of the valence band (Burstein–Moss effects); the high energy shoulder P4 (0.787eV) was by the co-effect of quantum confinement and the Burstein–Moss effects due to the small size distribution of InN wetting layers.</P>