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A Double-channel Four-band True Color Night Vision System
Yunfeng Jiang,Dongsheng Wu,Jie Liu,Kuo Tian,Dan Wang 한국광학회 2022 Current Optics and Photonics Vol.6 No.6
By analyzing the signal-to-noise ratio (SNR) theory of the conventional true color night vision system, we found that the output image SNR is limited by the wavelength range of the system response λ 1and λ 2 . Therefore, we built a double-channel four-band true color night vision system to expand the system response to improve the output image SNR. In the meantime, we proposed an image fusion method based on principal component analysis (PCA) and nonsubsampled shearlet transform (NSST) to obtain the true color night vision images. Through experiments, a method based on edge extraction of the targets and spatial dimension decorrelation was proposed to calculate the SNR of the obtained images and we calculated the correlation coefficient (CC) between the edge graphs of obtained and reference images. The results showed that the SNR of the images of four scenes obtained by our system were 125.0%, 145.8%, 86.0% and 51.8% higher, respectively, than that of the conventional tri-band system and CC was also higher, which demonstrated that our system can get true color images with better quality.
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Yunfeng He,Xiaohou Wu,Wei Tang,Daiyin Tian,Chunli Luo,Zhikang Yin,Hu Du 대한의학회 2008 Journal of Korean medical science Vol.23 No.5
The oncogenic isoform of the p63 protein, delta Np63 ( Np63), plays an important role in the pathogenesis of many epithelial carcinomas, and emerging evidences suggest that Np63 is a promising drug target. However, the functions of Np63 in transitional cell carcinoma of bladder (TCCB) are poorly defined. In this study, a Np63 shRNA expression vector was transfected into TCCB cell line 5637 and cell cycling, cell proliferation and protein expression were assessed by flow cytometry and 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-dimethyl tetrazolium bromide (MTT) assay, and immunohistochemistry, respectively. The Np63 shRNA expression vector was also injected into 5637 cell xenograft tumors in nude mice, and tumor size was measured, tumor tissue morphology was assessed by immunohistopathology and transmission electron microscopy. In the in vitro study, Np63 shRNA transfection caused successful Np63 gene silencing and resulted in significant arrest of cell cycling and cellular proliferation (p<0.05) as well as cyclin D1 expression. In the nude mouse xenograft model, Np63 shRNA greatly inhibited tumor growth, induced tumor cell apoptosis (p<0.05) and resulted in cyclin D1 downregulation. Our data suggest that Np63 may play an oncogenic role in TCCB progression through promoting cell survival and proliferation. Intratumoral administration of Np63-specific shRNA suppressed tumor Np63 expression and cellular proliferation while promoted tumor cellular apoptosis, and therefore inhibited tumor growth and improved survival of xenograft-bearing mice, which was not accompanied by significant signs of systemic toxicity.
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Wang Haoran,Wu Tao,Hua Feng,Sun Jinpeng,Bai Yunfeng,Wang Weishun,Liu Jun,Zhang Mingshun 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.3
BACKGROUND: Recent evidence suggests that IL-33, a novel member of the IL-1b family, is involved in organ fibrosis. However, the roles of IL-33 and its receptor ST2 in epidural fibrosis post spine operation remain elusive. METHODS: A mouse model of epidural fibrosis was established after laminectomy. IL-33 in the wound tissues post laminectomy was measured with Western blotting, ELISA and immunoflurosence imaging. The fibroblast cell line NIH- 3T3 and primary fibroblasts were treated with IL-33 and the mechanisms of maturation of fibroblasts into myofibroblasts were analyzed. To explore roles of IL-33 and its receptor ST2 in vivo, IL-33 knockout (KO) and ST2 KO mice were employed to construct the model of laminectomy. The epidural fibrosis was evaluated using H&E and Masson staining, western-blotting, ELISA and immunohistochemistry. RESULTS: As demonstrated in western blotting and ELISA, IL-33 was increased in epidural wound tissues post laminectomy. The immunoflurosence imaging revealed that endothelial cells (CD31?) and fibroblasts (a-SAM?) were major producers of IL-33 in the epidural wound tissues. In vitro, IL-33 promoted fibroblast maturation, which was blocked by ST2 neutralization antibody, suggesting that IL-33-promoted-fibroblasts maturation was ST2 dependent. Further, IL-33/ ST2 activated MAPK p38 and TGF-b pathways. Either p38 inhibitor or TGF-b inhibitor decreased fibronectin and a-SAM production from IL-33-treated fibroblasts, suggesting that p38 and TGF-b were involved with IL-33/ST2 signal pathways in the fibroblasts maturation. In vivo, IL-33 KO or ST2 KO decreased fibronectin, a-SMA and collagen deposition in the wound tissues of mice that underwent spine surgery. In addition, TGF-b1 was decreased in IL-33 KO or ST2 KO epidural wound tissues. CONCLUSION: In summary, IL-33/ST2 promoted fibroblast differentiation into myofibroblasts via MAPK p38 and TGFb in a mouse model of epidural fibrosis after laminectomy.
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Aerodynamic performance of a novel wind barrier for train-bridge system
He, Xuhui,Shi, Kang,Wu, Teng,Zou, Yunfeng,Wang, Hanfeng,Qin, Hongxi Techno-Press 2016 Wind and Structures, An International Journal (WAS Vol.23 No.3
An adjustable, louver-type wind barrier was introduced in this study for improving the running safety and ride comfort of train on the bridge under the undesirable wind environment. The aerodynamic characteristics of both train and bridge due to this novel wind barrier was systematically investigated based on the wind tunnel tests. It is suggested that rotation angles of the adjustable blade of the louver-type wind barrier should be controlled within $90^{\circ}$ to achieve an effective solution in terms of the overall aerodynamic performance of the train. Compared to the traditional grid-type wind barrier, the louver-type wind barrier generally presents better aerodynamic performance. Specifically, the larger decrease of the lift force and overturn moment of the train and the smaller increase of the drag force and torsional moment of the bridge resulting from the louver-type wind barrier were highlighted. Finally, the computational fluid dynamics (CFD) technique was applied to explore the underlying mechanism of aerodynamic control using the proposed wind barrier.
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An Improved Interleaved Flyback Converter with Reduced Voltage Stress and Current Auto-sharing
Chen Zhangyong,Shen Lanxiao,Wu Yunfeng 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.4
The interleaved fl yback converters are widely used for the application of the renewable energy sources, electric vehicles, LED drivers et al. However, there are some challenges for this topology, such as leakage inductor energy of transformer, output current ripple, and high voltage stress of main switch. In order to solve the above problem existed in the converter, an improved interleaved fl yback converter with adding series capacitor is proposed in this paper. Through utilizing of active clamp technique for the converter, leakage inductor energy is observed and released, zero voltage switching of main switch are achieved. Furthermore, intrinsic current sharing of two phase fl yback converter could be automatic obtained without any voltage/current sensors by through charge balance for series capacitor existed in this converter topology. Thus, output current ripple is reduced and high effi ciency of interleaved fl yback converter is acquired. Comprehensive operational principle analysis and performance analysis are provided. Finally, a 60 W prototype is built to verify the analysis.
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Yanmei Feng,Zhiqiang Wang,Yunfeng Yang,Xiang-Feng Wu,Xiaodong Gong,Yajian Liu,Yufei Li,Zuo-Lin Cao,Chao Wang,Xin Tong 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.7
The Ag2SO3/NaNbO3 hybrids have been fabricated via a facile method at room temperature. Several methods such as X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, scanning electron microscopy, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy were used to characterize the samples. Moreover, the photocatalytic activity of the samples was assessed by degradation of rhodamine B and methyl orange under the visible light illumination. Experimental results indicated the photocatalytic degradation efficiency of the as-fabricated hybrids was first increased and then decreased with increasing the dosage of NaNbO3. When the molar ratio of Ag2SO3 to NaNbO3 was 1:0.7, the as-fabricated composites had the best photodegradation efficiency of 96.4% in 30 min for rhodamine B and 97.1% in 60 min for methyl orange, respectively. These were obviously higher than that of pure samples. Furthermore, Ag2SO3 was conjugated with NaNbO3 via chemical-bonds rather than physical contact. In addition, the possible photocatalytic degradation mechanism was also provided and the main roles during the process of photocatalytic degradation were played by holes.
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Aerodynamic performance of a novel wind barrier for train-bridge system
Xuhui He,Kang Shi,Teng Wu,Yunfeng Zou,Hangfeng Wang,HongXi Qin 한국풍공학회 2016 Wind and Structures, An International Journal (WAS Vol.23 No.3
An adjustable, louver-type wind barrier was introduced in this study for improving the running safety and ride comfort of train on the bridge under the undesirable wind environment. The aerodynamic characteristics of both train and bridge due to this novel wind barrier was systematically investigated based on the wind tunnel tests. It is suggested that rotation angles of the adjustable blade of the louver-type wind barrier should be controlled within 90 to achieve an effective solution in terms of the overall aerodynamic performance of the train. Compared to the traditional grid-type wind barrier, the louver-type wind barrier generally presents better aerodynamic performance. Specifically, the larger decrease of the lift force and overturn moment of the train and the smaller increase of the drag force and torsional moment of the bridge resulting from the louver-type wind barrier were highlighted. Finally, the computational fluid dynamics (CFD) technique was applied to explore the underlying mechanism of aerodynamic control using the proposed wind barrier.
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Chen Zhangyong,Zheng Zhanchao,Tang Xuan,Wu Yunfeng 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1
In this paper, combine hybrid modulation strategy and Model predictive control (MPC) for Dual active bridge (DAB) converter is presented to achieve high efciency of wide load range and fast dynamic response for bidirectional power fow conversion. Through ofine optimization of DAB converter at steady state, only one control variable is used to reduce computational burden, and without complex algorithm in the cost function for MPC strategy. In addition, based on the simpilifed average mode of DAB converter, diferent predictive currents are derived. Besides, three scenarios of smooth mode transition for the hybrid control strategy is given in detail. Thus, fast dynamic response for mode transition and high efciency for wide range is guaranteed by the proposed strategy. Finally, an experimental prototype of DAB converter is built and tested for verifying the steady state and fast transition with diferent operation modes performance.
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