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Student Network Learning via Evolutionary Knowledge Distillation [article]

Kangkai Zhang, Chunhui Zhang, Shikun Li, Dan Zeng, Shiming Ge
2021 arXiv   pre-print
Zhang, S. Li and S.  ...  Zhang et al. [42] proposed an online training framework called self-distillation, which forces student to refine its knowledge inside the network, thereby improving itself.  ... 
arXiv:2103.13811v1 fatcat:wdv2xwia4bhvbg3eh5w4eg4pvm

Tuning the plasmonic resonance peak for Al nanorods on AlGaN layer to deep ultraviolet band

Ziqiang Zhao, Chunshuang Chu, Gai Zhang, Kangkai Tian, Yonghui Zhang, Zi-Hui Zhang
2021 IEEE Photonics Journal  
Tuning the plasmonic resonance peak to the deep ultraviolet (DUV) band is critical for plasmonic-enhanced AlGaN-based DUV photodetector. However, the high refractive index of AlGaN layer seriously limits the plasmonic resonance peak in DUV band. Therefore, in this work, we study how various Al nanoparticles on the AlGaN layer surface affect the plasmonic resonance performance. Compared with the Al-based nanosphere, nanohemisphere and nanodisk, the Al-based nanorod is the most suitable candidate
more » ... for AlGaN-based DUV photodetectors. This is because the DUV plasmonic dipolar mode excited from the upper part of nanorod is not affected by the interface between the nanorods and the AlGaN layer. However, the interface also leads to another plasmonic dipolar mode at longer wavelengths. Moreover, the DUV plasmonic resonance peak will be influenced by the diameter,the height and the Al2O3 layer thickness. We also find that the diffraction can enhance the resonance peak intensity when the Al nanorod period is smaller than the resonance peak wavelength. Besides, to make the enhanced electric field located in active layer, a layer of Ga 2 O 3 shell is proposed to cover Al nanorods,which causes a quadrupole mode in DUV band excited from the sidewall of Al nanorods.
doi:10.1109/jphot.2021.3112667 fatcat:lz35urultbe2dp7fh2sidqrphy

Polarization self-screened multiple quantum wells for deep ultraviolet light-emitting diodes to enhance the optical power

Chunshuang Chu, Kangkai Tian, Hua Shao, Jiamang Che, Yonghui Zhang, Zi-Hui Zhang
2021 IEEE Photonics Journal  
Tian, Hua Shao, Jiamang Che, Yonghui Zhang and Zi-Hui Zhang R electron leakage level [15] .  ...  to the reduced conduction band barrier height and the stronger Polarization self-screened multiple quantum wells for deep ultraviolet light-emitting diodes to enhance the optical power Chunshuang Chu, Kangkai  ... 
doi:10.1109/jphot.2021.3115341 fatcat:dtykm4pbnrg2jcejkommmv55lu

Decreased Dp71 expression is associated with gastric adenocarcinoma prognosis

Sipin Tan, Jin Tan, Sichuang Tan, Shuai Zhao, Xiaoxia Cao, Zhikang Chen, Qiaocheng Weng, Huali Zhang, Kangkai Wang, Jiang Zhou, Xianzhong Xiao
2016 OncoTarget  
For the first time, dramatically decreased Dp71 protein and mRNA was found in 34 pairs of resected primary gastric adenocarcinoma. Immunohistochemistry identified Dp71 expression suppressed in 72.2% of 104 gastric cancer patients. The decreased Dp71 expression was significantly correlated with cancer differentiation (P=0.001) and lymph vascular invasion (p=0.041). Decreased Dp71 expression was associated with a poor gastric adenocarcinoma prognosis (P=0.001). Significantly less Dp71 mRNA and
more » ... tein were found in BGC823, SGC7901,AGS compared with GES-1. Via increasing lamin B1 mRNA and protein, enforced Dp71d and Dp71f expression resulted in SGC7901 proliferation inhibition. Co-IP proved interaction of Dp71 with lamin B1 in GES-1 cells. Further expression characterization showed reduced lamin B1 in gastric cancer tissue and cancer cells. Increasing lamin B1 expression results in the growth inhibition of SGC7901, which suggests that Dp71-lamin B1 protein complex plays an important role for the newly identified tumor suppressive function of Dp71.
doi:10.18632/oncotarget.10724 pmid:27449096 pmcid:PMC5288215 fatcat:qjwtcwozifddhnfokylopduc2e

Effects of Meshed p-type Contact Structure on the Light Extraction Effect for Deep Ultraviolet Flip-Chip Light-Emitting Diodes

Yuxin Zheng, Yonghui Zhang, Ji Zhang, Ce Sun, Chunshuang Chu, Kangkai Tian, Zi-Hui Zhang, Wengang Bi
2019 Nanoscale Research Letters  
In this work, flip-chip AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) with various meshed contact structures are systematically investigated via three-dimensional finite-difference time-domain (3D FDTD) method. It is observed that both transverse electric (TE)- and transverse magnetic (TM)-polarized light extraction efficiencies (LEEs) are sensitive to the spacing and inclined angle for the meshed structure. We also find that the LEE will not be increased when a large filling
more » ... tor is adopted for the meshed structures, which is because of the competition among the p-GaN layer absorption, the Al metal plasmon resonant absorption, and the scattering effect by meshed structures. The very strong scattering effect occurring in the hybrid p-GaN nanorod/p-AlGaN truncated nanocone contacts can enormously enhance the LEE for both TE- and TM-polarized light, e.g., when the inclined angle is 30°, the LEE for the TE- and TM-polarized light can be increased by ~ 5 times and ~ 24 times at the emission wavelength of 280 nm, respectively.
doi:10.1186/s11671-019-2984-0 pmid:31049737 pmcid:PMC6497700 fatcat:flfuugd6rfc7zdsqcwu7phir3e

The Effect of Sapphire Substrates on Omni-Directional Reflector Design for Flip-Chip Near-Ultraviolet Light-Emitting Diodes

Yonghui Zhang, Ji Zhang, Yuxin Zheng, Ce Sun, Kangkai Tian, Chunshang Chu, Zi-Hui Zhang, Jay Guoxu Liu, Wengang Bi
2019 IEEE Photonics Journal  
IEEE. Translations and content mining are permitted for academic research only. Personal use is also permitted, but republication/redistribution requires IEEE permission. See for more information. Abstract: In this paper, we investigate the effect of omni-directional reflectors (ODRs) on the light extraction efficiency (LEE) for flip-chip near-ultraviolet light-emitting diodes (LEDs) on patterned (PSS) and flat sapphire
more » ... bstrate (FSS) using three-dimensional finite-difference time-domain method. Different design principles of ODR for the flip-chip LEDs on PSS and FSS are proposed to attain optimum LEE. For the flip-chip LED on FSS, the LEE curve is oscillatory with changing the thickness of the SiO 2 layer as a result of the coherent interference in the ODR and the optical cavity tuning effect for light source. Therefore, the thickness of the p-GaN needs to satisfy even times of quarter wave and the thickness of SiO 2 needs to be quarter wave. However, for the flip-chip LED on PSS, both the total internal reflection and the surface plasmon polariton resonance absorption play a major role leading to LEE increasing as the thickness of SiO 2 layer increases. As a result, SiO 2 layer with a thickness of over one wavelength is better, because the energy of evanescent wave decays to sufficiently negligible when it reaches the Al metal.
doi:10.1109/jphot.2018.2889319 fatcat:4d4rxhkw35eh7djo2urcbrqula

Optimization Strategy of 4H-SiC Separated Absorption Charge and Multiplication Avalanche Photodiode Structure for High Ultraviolet Detection Efficiency

Jianquan Kou, KangKai Tian, Chunshuang Chu, Yonghui Zhang, Xingye Zhou, Zhihong Feng, Zi-Hui Zhang
2019 Nanoscale Research Letters  
In this work, parametric investigations on structural optimization are systematically made for 4H-SiC-based separated absorption charge and multiplication (SACM) avalanche ultraviolet photodiode (UV APD). According to our results, the breakdown voltage can be strongly affected by the thickness for the multiplication layer and the doping concentration for the charge control layer. The thickness for the n-type ohmic contact layer, the absorption layer, and the charge control layer can remarkably
more » ... ffect the light penetration depth, which correspondingly influences the number of photo-generated electron-hole pairs, and therefore the aforementioned layer thickness has a strong impact on the responsivity for SACM APD. For enhancing the responsivity of the APD, we require a reduced energy band barrier height at the interface of the optical absorption layer and the charge control layer, so that the promoted carrier transport into the multiplication layer can be favored. In addition, we investigate positive beveled mesas with smaller angles so as to reduce the electric field at the mesa edge. Thus, the dark current is correspondingly suppressed.
doi:10.1186/s11671-019-3227-0 pmid:31889233 pmcid:PMC6937367 fatcat:onj6lwow4jghnkjga2e53gw5m4

On the p-AlGaN/n-AlGaN/p-AlGaN Current Spreading Layer for AlGaN-based Deep Ultraviolet Light-Emitting Diodes

Jiamang Che, Chunshuang Chu, Kangkai Tian, Jianquan Kou, Hua Shao, Yonghui Zhang, Wengang Bi, Zi-Hui Zhang
2018 Nanoscale Research Letters  
In this report, AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) with different p-AlGaN/n-AlGaN/p-AlGaN (PNP-AlGaN) structured current spreading layers have been described and investigated. According to our results, the adopted PNP-AlGaN structure can induce an energy barrier in the hole injection layer that can modulate the lateral current distribution. We also find that the current spreading effect can be strongly affected by the thickness, the doping concentration, the PNP loop,
more » ... and the AlN composition for the inserted n-AlGaN layer. Therefore, if the PNP-AlGaN structure is properly designed, the forward voltage, the external quantum efficiency, the optical power, and the wall-plug efficiency for the proposed DUV LEDs can be significantly improved as compared with the conventional DUV LED without the PNP-AlGaN structure.
doi:10.1186/s11671-018-2776-y pmid:30411256 pmcid:PMC6223402 fatcat:inmt5gvjyjemto5odjnxbfcrtq

Three-dimensional band diagram in lateral polarity junction III-nitride heterostructures

Wei Guo, Somak Mitra, Jie'an Jiang, Houqiang Xu, Moheb Sheikhi, Haiding Sun, Kangkai Tian, Zi-hui Zhang, Haibo Jiang, Iman S. Roqan, Xiaohang Li, Jichun Ye
2019 Optica  
The 2D band diagram comprising out-of-plane potentials has been ubiquitously utilized for III-nitride heterostructures. Here, we propose the 3D band diagram based on unambiguous evidences in luminescence and carrier dynamics for lateral polarity junction quantum wells: although electrons and holes are separated out-of-plane in quantum wells by polarization, different band diagram heights lead to secondary carrier injection in-plane, causing electrons to transport from the III-to N-polar domains
more » ... to recombine with holes therein with large wavefunction overlap. We also show that utilization of the 3D band diagram can be extended to single-polarity structures to analyze carrier transport and dynamics, providing new dimensions for accurate optical device design.
doi:10.1364/optica.6.001058 fatcat:yrs6ihijyvdmfmhsionoqt6cye

Sinomenine Hydrochloride Protects against Polymicrobial Sepsis via Autophagy

Yu Jiang, Min Gao, Wenmei Wang, Yuejiao Lang, Zhongyi Tong, Kangkai Wang, Huali Zhang, Guangwen Chen, Meidong Liu, Yongming Yao, Xianzhong Xiao
2015 International Journal of Molecular Sciences  
Sepsis, a systemic inflammatory response to infection, is the major cause of death in intensive care units (ICUs). The mortality rate of sepsis remains high even though the treatment and understanding of sepsis both continue to improve. Sinomenine (SIN) is a natural alkaloid extracted from Chinese medicinal plant Sinomenium acutum, and its hydrochloride salt (Sinomenine hydrochloride, SIN-HCl) is widely used to treat rheumatoid arthritis (RA). However, its role in sepsis remains unclear. In the
more » ... present study, we investigated the role of SIN-HCl in sepsis induced by cecal ligation and puncture (CLP) in BALB/c mice and the corresponding mechanism. SIN-HCl treatment improved the survival of BALB/c mice that were subjected to CLP and reduced multiple organ dysfunction and the release of systemic inflammatory mediators. Autophagy activities were examined using Western blotting. The results showed that CLP-induced autophagy was elevated, and SIN-HCl treatment further strengthened the autophagy activity. Autophagy blocker 3-methyladenine (3-MA) was used to investigate the mechanism of SIN-HCl OPEN ACCESS Int. J. Mol. Sci. 2015, 16 2560 in vitro. Autophagy activities were determined by examining the autophagosome formation, which was shown as microtubule-associated protein light chain 3 (LC3) puncta with green immunofluorescence. SIN-HCl reduced lipopolysaccharide (LPS)-induced inflammatory cytokine release and increased autophagy in peritoneal macrophages (PM). 3-MA significantly decreased autophagosome formation induced by LPS and SIN-HCl. The decrease of inflammatory cytokines caused by SIN-HCl was partially aggravated by 3-MA treatment. Taken together, our results indicated that SIN-HCl could improve survival, reduce organ damage, and attenuate the release of inflammatory cytokines induced by CLP, at least in part through regulating autophagy activities.
doi:10.3390/ijms16022559 pmid:25625512 pmcid:PMC4346851 fatcat:s54quzqy7vcdxkrno53bffpooq

HSF1 functions as a transcription regulator for Dp71 expression

Jin Tan, Sichuang Tan, Hexin Zheng, Meidong Liu, Guangwen Chen, Huali Zhang, Kangkai Wang, Sipin Tan, Jiang Zhou, Xian-zhong Xiao
2014 Cell stress & chaperones (Print)  
The extract preparation and binding reaction were performed as previously described (Zhang et al. 2011) .  ... 
doi:10.1007/s12192-014-0558-8 pmid:25430510 pmcid:PMC4326382 fatcat:kyw5f4hporayfevim3atdclz7q

A Deep Learning Method for Bias Correction of ECMWF 24–240 h Forecasts

Lei Han, Mingxuan Chen, Kangkai Chen, Haonan Chen, Yanbiao Zhang, Bing Lu, Linye Song, Rui Qin
2021 Advances in Atmospheric Sciences  
AbstractCorrecting the forecast bias of numerical weather prediction models is important for severe weather warnings. The refined grid forecast requires direct correction on gridded forecast products, as opposed to correcting forecast data only at individual weather stations. In this study, a deep learning method called CU-net is proposed to correct the gridded forecasts of four weather variables from the European Centre for Medium-Range Weather Forecast Integrated Forecasting System global
more » ... l (ECMWF-IFS): 2-m temperature, 2-m relative humidity, 10-m wind speed, and 10-m wind direction, with a forecast lead time of 24 h to 240 h in North China. First, the forecast correction problem is transformed into an image-to-image translation problem in deep learning under the CU-net architecture, which is based on convolutional neural networks. Second, the ECMWF-IFS forecasts and ECMWF reanalysis data (ERA5) from 2005 to 2018 are used as training, validation, and testing datasets. The predictors and labels (ground truth) of the model are created using the ECMWF-IFS and ERA5, respectively. Finally, the correction performance of CU-net is compared with a conventional method, anomaly numerical correction with observations (ANO). Results show that forecasts from CU-net have lower root mean square error, bias, mean absolute error, and higher correlation coefficient than those from ANO for all forecast lead times from 24 h to 240 h. CU-net improves upon the ECMWF-IFS forecast for all four weather variables in terms of the above evaluation metrics, whereas ANO improves upon ECMWF-IFS performance only for 2-m temperature and relative humidity. For the correction of the 10-m wind direction forecast, which is often difficult to achieve, CU-net also improves the correction performance.
doi:10.1007/s00376-021-0215-y fatcat:64ig5klp4fdsde37ndlu2jnwfu

Manipulation of Si Doping Concentration for Modification of the Electric Field and Carrier Injection for AlGaN-Based Deep-Ultraviolet Light-Emitting Diodes

Mengqian Fang, Kangkai Tian, Chunshuang Chu, Yonghui Zhang, Zi-Hui Zhang, Wengang Bi
2018 Crystals  
Electron overflow is one of the key factors that limit the quantum efficiency for AlGaN-based deep-ultraviolet light-emitting diodes. In this work, we report a numerical study to improve the electron injection efficiency by manipulating the electric field profiles via doping the n-Al 0.60 Ga 0.40 N electron source layer with different concentrations and reveal the physical mechanism of the Si doping effect on the electron and the hole injection. By utilizing the appropriate doping
more » ... the electric field will reduce the electron drift velocity and, thus, the mean free path. Therefore, a higher electron capture efficiency by the multiple quantum wells (MQWs) and an increase of the hole concentration in the active region can be realized, resulting in an improved radiative recombination rate and an optical output power. Crystals 2018, 8, 258 2 of 8 p-EBL [6] and the AlInGaN polarization matched p-EBL [7] . In addition, the superlattice p-EBL enables a good reflectivity for those electrons with high thermal energy, provided that the thickness of the superlattice structure is fully optimized [8, 9] . In addition, designs of novel QB structures for DUV LEDs are proposed to increase the efficiency of electron injection, such as QBs with graded thickness [10] and thickened last QB with p-type doping [11] . Specifically, Guo et al. propose to insert a "spike" layer with even higher AlN composition in each AlGaN-based quantum barrier for DUV LEDs [12] . By doing so, the quantum wells can better capture the electrons, having reduced energy. The underlying mechanism for the proposed QB is that the polarization induced electric field in the "spike" Al-rich layer can reduce the kinetic energy for electrons, which, simultaneously, reduces the electron drift velocity and then decreases the electron mean free path. Next, the drift velocity for the free electrons can also be reduced by using an electron cooler (EC) or an n-type electron blocking layer [13, 14] . Inspired by Refs. [12] [13] [14] , we manipulate the electric field of the n-Al 0.60 Ga 0.40 N electron source layer by tuning the Si doping concentration [see Figure 1 ]. In this study, a very strong electric field can be generated if the Si doping concentration in the n-Al 0.60 Ga 0.40 N layer becomes high. Moreover, the generated electric field therein can decelerate the electrons and, hence, the electrons will become less mobile. As a result, the electron mean free path will become shorter and the electrons are more likely to fall into the MQWs, with a longer dwell time to more efficiently recombine with the holes. However, LEDs, with excessively higher Si doping concentrations, will, in turn, displace the recombination position and, therefore, hinder the hole injection, leading to an overall reduced radiative recombination rate [15] . Therefore, it is critical to design the DUV LEDs with an optimized Si doping level for maximizing both the carrier injection and the device performance. Subsequently, details will be given and discussed. Our work is different from the reports in Refs. [16, 17] . Ryu et al. report that, by increasing the Si doping concentration for the n-GaN layer in GaN-based vertical blue LEDs, improved current spreading and more uniform carrier distribution in the quantum wells can be obtained [16] . Lee et al. report that the crystal quality for the [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] oriented n-GaN layer and the subsequent InGaN/GaN multiple quantum wells can be improved by properly increasing the Si doping concentration for the n-GaN layer. The reduced defect density in the n-GaN layers suppresses the carrier scattering and carrier mobility is, correspondingly, increased, which enables more efficient electron injection into the active region [17] . Therefore, this work reveals the impact of the Si dopants in increasing the DUV LED performance from another perspective.
doi:10.3390/cryst8060258 fatcat:tee54xpigndkreldt7rjclog7u

On the impact of electron leakage on the efficiency droop for AlGaN based deep ultraviolet light emitting diodes

Chunshuang Chu, Kangkai Tian, Jiamang Che, Hua Shao, Jianquan Kou, Yonghui Zhang, Zi-Hui Zhang, Hao-Chung Kuo
2020 IEEE Photonics Journal  
In this work, we have investigated the origin of efficiency droop for AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs). We find that the efficiency droop is likely to be caused by the electron leakage for DUV LEDs studied in this work. The electron leakage arises from the unbalanced electron and hole injection efficiencies. The correlation between the efficiency droop and the electron leakage can be numerically calculated by manipulating the conduction band barrier height of the
more » ... lGaN electron blocking layer (p-EBL) for the proposed DUV LEDs. For the purpose of demonstrating that the efficiency droop for DUV LEDs can be experimentally decreased by reducing the electron leakage, a p + -GaN/In 0.15 Ga 0.85 N/n + -GaN tunnel junction on DUV LED is grown by using metal organic chemical vapor deposition (MOCVD) technology. The tunnel junction helps to enhance the hole injection, thus decreasing the electron leakage and the efficiency droop. Moreover, the parasitic emission in the p-type hole injection layer is no longer observed thanks to the decreased electron leakage level.
doi:10.1109/jphot.2020.2997343 fatcat:6latzucsuvepjg5ofb6ibcujpy

Supplementary document for Investigation of step-type quantum wells with slightly varied InN composition for GaN-based yellow micro light-emitting diodes - 5136891.pdf

Hua Shao, Chunshuang Chu, Chia-Ming Chuang, Sheng Hang, Jiamang Che, Jianquan Kou, Kangkai Tian, Yonghui Zhang, Quan Zheng, Zi Hui Zhang
Impact of different step-type quantum wells on the emission wavelength
doi:10.6084/m9.figshare.14208533.v1 fatcat:mtmtrlw4dzd4xe4bdwoaysh47a
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