Color Adjustment Based on Support Vector Regression for Multi-View Video

Huadong Sun,Xuesong Jin,Zhipeng Fan,Lizhi Zhang,Qian Wu 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.1

Significant color discrepancies between the different camera views can be observed in multi-view video sequences. In this paper, a color adjustment algorithm based on support vector regression is proposed. A mapping function is established by extracted feature points from original-image and target-image. Then the mapping function is applied to the original image to obtain the corrected image. Experimental results show that the proposed method can produce good correction result. It also shows that the color differences between multi-view video can be effectively reduced by SVR.

Hypermethylation of Frizzled1 is associated with Wnt/β-catenin signaling inactivation in mesenchymal stem cells of patients with steroid-associated osteonecrosis

Zhibo Sun,Jing Jiao,Feng Liu,Yue Yang,Shanfeng Zhang,Zhenhua Fang,Zhipeng Dai,Zhibo Sun 생화학분자생물학회 2019 Experimental and molecular medicine Vol.51 No.-

The Wnt/β-catenin signaling pathway is associated with the pathogenesis of steroid-induced osteonecrosis. Our investigation studied whether aberrant CpG island hypermethylation of the FZD1 gene was present in patients with osteonecrosis of the femoral head (ONFH), which results in Wnt/β-catenin signaling inactivation and subsequent cell dysfunction. Bone marrow was collected from the proximal femurs of patients with steroid-associated ONFH (n = 21) and patients with new femoral neck fractures (n = 22), and then mesenchymal stem cells (MSCs) were isolated. We investigated cell viability, the transcription and translation levels of Wnt/β-catenin signaling-related genes, the extent of methylation at CpG islands of the FZD1 promoter, and the osteogenic and adipogenic differentiation abilities of MSCs from the control group and from the ONFH group treated with or without 5′-Aza-dC. According to the results, MSCs from the ONFH group showed a reduced proliferation ability, low transcription and translation levels of FZD1, inhibition of the Wnt/β-catenin signaling pathway, weakened osteogenesis and enhanced adipogenesis ability. Aberrant CpG island hypermethylation of FZD1 was observed in the ONFH group. Treatment with 5’-Aza-dC resulted in de novo FZD1 expression, reactivation of the Wnt/β-catenin signaling pathway and promotion of osteogenesis. Taken together, our study not only provides novel insights into the regulation of the Wnt/β-catenin signaling pathway in this disease but also reveals potential for the use of demethylating agents for the treatment of GC-associated ONFH.

A long-term anti-corrosion and cathodic delamination resistant epoxy coating based on COF grafted GO nanofillers

Tianxiang Sun,Kai Jin,Wei Wang,Wen Li,Tong Wang,Tengxun Yang,Jia Cheng,Zhipeng Zhao,Shougang Chen 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.128 No.-

Here, a long-term anti-corrosive epoxy (EP) coating based on nano-hybrid filler was developed. The surfaceof graphene oxide (GO) was aminated with (3-aminopropyl) triethoxysilane (APTES), and then theporous covalent organic framework (COF) was in-situ grown on amino functionalized graphene oxide(FGO) nanosheets by Schiff-based reaction to prepare FGO-COF nanofillers. Different characterizationmethods proved the successful modification of GO nanosheets with COF particles. The excellent waterresistance of composite coatings was characterized through contact angle, adhesion, and water uptaketests. Transmission electron microscope (TEM) and molecular dynamics (MD) methods showed thatthe grafting of COF enhanced the dispersion and compatibility of GO in the coating. EIS measurements,salt spray analysis and cathodic delamination test indicated the significant improvements in the protectiveproperties of the composite coatings compared with pure EP coating. The low-frequency impedancemodulus of 1% FGO-COF composite coating reached higher than 6.8 109 Xcm2 after immersed in seawater for 60 days. In addition, the 1% FGO-COF composite coating performed only 34% delamination ratioafter 120 h cathodic delamination test.

Carbon Nanotube Paper as Anode for Flexible Lithium-Ion Battery

Xiaogang Sun,Zhenhong Liu,Neng Li,Xiaoyong Wu,Yanyan Nie,Zhipeng Pang,Lifu Yue,Hao Tang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.11

In this investigation, multiwalled carbon nanotube (MWCNT) paper consists of MWCNTs and cellulose was fabricated by traditional paper-making method. It was applied directly as negative electrode in flexible lithium ion battery to replace ordinary electrode which is combined with anode material and current collector. The electrochemical performances of the as-produced MWCNT paper (AMP) and carbonized MWCNT paper (CMP) were evaluated in this study. The morphology and structure of the MWCNT papers were observed by scanning electron microscopy (SEM). The electrochemical performance of the battery was operated by cell test and electrochemical impedance spectroscopy (EIS) measurement. The charging and discharging results indicated that the CMP behaves with higher capacity than AMP. And the EIS analysis showed that a lower charge transfer resistance can be obtained in the CMP. The excellent electrochemical performance verifies the feasibility of MWCNT papers as a promising candidate for the anode in flexible lithium ion battery.

A Novel PCCM Voltage-Fed Single-Stage Power Factor Correction Full-Bridge Battery Charger

Taizhi Zhang,Zhipeng Lu,Qinsong Qian,Weifeng Sun,Shengli Lu 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

A novel pseudo-continuous conduction mode (PCCM) voltage-fed single-stage power factor correction (PFC) full-bridge battery charger is proposed in this paper. By connecting a freewheeling transistor in parallel with an input inductor, the PFC cell can operate in the PCCM with a constant duty ratio. Thus, the dc/dc stage can be designed using this constant duty ratio and the restriction on the duty ratio of the PFC cell is eliminated. As a result, the input current distortion is less and the dc bus voltage becomes controllable over the wide output power range of the battery charger. Moreover, the operation principle of the dc/dc stage is designed to be similar to that of a conventional phase-shifted full-bridge converter. Therefore, it is easy to implement. In this paper, the operation of the new converter is explained, and the design considerations of the controller and key parameters are presented. Simulation and experimental results obtained from a 1 kW prototype are given to confirm the operation of the proposed converter.

Protective strategy for the caudate lobe bile duct during left hemihepatectomy based on imaging data analysis

Zhengyi Wu*,Liang Sun*,Ke Ning,Zhendong Chen,Zhipeng Wu,Hanqing Yang,Jinlong Yan*,Xiangbao Yin* 대한외과학회 2023 Annals of Surgical Treatment and Research(ASRT) Vol.105 No.6

Purpose: This study was performed to analyze the rule of confluence of the caudate lobe bile duct (CLD) into the left hepatic duct (LHD) and to discuss the protective strategy during left hemihepatectomy. Methods: MRI of 400 patients and T-tube angiography images of 100 patients were collected, and the imaging rules of the confluence of the CLD into the LHD were summarized. The clinical data of 33 patients who underwent left hemihepatectomy using the protective strategy were analyzed. Results: MRI and T-tube angiography images showed that the length from the confluence point of the CLD into the LHD to the confluence of the left and right hepatic ducts was 1.19 ± 0.40 cm and 1.26 ± 0.39 cm, respectively. The average angle between the longitudinal axis of the 2 bile ducts was 68.27° ± 22.59° and 66.58 ± 22.88°, respectively. Coronal and cross-sectional images showed that inflow from the foot side to the cranial side was noted in 79.8% and 82.0% of patients, respectively, and inflow from the dorsal to the ventral side was observed in 84.5% and 88.0%, respectively. Based on these imaging rules, the safe transection length and plane were summarized, and the CLD was effectively protected in 33 cases of left hemihepatectomy. Conclusion: In left hemihepatectomy, the LHD should be transected at least 1.5 cm away from the confluence of the left and right hepatic ducts, and the plane of transection should be oblique to the dorsal side at an angle of 45° with the LHD, these parameters represent an effective strategy to protect the CLD.

A Novel PCCM Voltage-Fed Single-Stage Power Factor Correction Full-Bridge Battery Charger

Zhang, Taizhi,Lu, Zhipeng,Qian, Qinsong,Sun, Weifeng,Lu, Shengli The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

A novel pseudo-continuous conduction mode (PCCM) voltage-fed single-stage power factor correction (PFC) full-bridge battery charger is proposed in this paper. By connecting a freewheeling transistor in parallel with an input inductor, the PFC cell can operate in the PCCM with a constant duty ratio. Thus, the dc/dc stage can be designed using this constant duty ratio and the restriction on the duty ratio of the PFC cell is eliminated. As a result, the input current distortion is less and the dc bus voltage becomes controllable over the wide output power range of the battery charger. Moreover, the operation principle of the dc/dc stage is designed to be similar to that of a conventional phase-shifted full-bridge converter. Therefore, it is easy to implement. In this paper, the operation of the new converter is explained, and the design considerations of the controller and key parameters are presented. Simulation and experimental results obtained from a 1 kW prototype are given to confirm the operation of the proposed converter.

Characterization and performance test of phenolphthalein poly(aryl ether ketone) fractionated by incremental poor solvent fractionation

Zengxu Qian,Jingwei Jiang,Yunlong Sun,Qiliang Yuan,Zhichao Wang,Zhipeng Wang,Guangyuan Zhou 한국고분자학회 2023 Macromolecular Research Vol.31 No.8

Though phenolphthalein poly(aryl ether ketone) (PEK-C) has gained attention as a special engineering plastic materials by virtue of its good thermal stability and favorable mechanical properties, its applications are limited due to its wide PDI during polymerization, which result in poor mechanical properties of PEK-C. In order to investigate the effect of molecular weight and polydispersity index (PDI) on PEK-C, an incremental poor solvent fractionation method was used to fractionate PEK-C. The process produced a series of grades with decreasing molecular weight and PDI. The LCP (linear cloud point) equation was combined with the grading method to find the optimal PEK-C/DMAc/ Non-solvent additives (NSA) system, which can be used to improve the grading efficiency. The obtained results showed that the incremental poor solvent fractionation method with the PEK-C/DMAc/EA system made the molecular weight distributed in the range of 25 ~ 113 kDa, PDI mostly distributed in the range of 1.1 ~ 1.4, and the narrowest PDI to reach 1.13, which could not be obtained through the condensation reaction. Meanwhile, we can also achieve expanded production. By fractionation, the elastic modulus of PEK-C film could be increased by up to 22.6%, elongation at break by up to 38.3%, the fracture strength by up to 38.2%, and impact strength of the sheest by up to 41.2%, while the polymer still maintained good thermal and UV shielding properties. This unique Polymer/Solution/NSA system can yield an effective design strategy for controlling its molecular weight and PDI and improving its mechanical performance.

Integrated Radial-axial Magnetic Bearing with Variable Permanent-Magnet Bias Flux In Situ

Xu Shilei,Li Jiajing,Wang Zhipeng,Sun Jinji,Ren Hongliang 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.4

Bias magnetic fl ux plays a crucial role in the performance of active magnetic bearings. However, the bias fl ux produced by NdFeB or SmCo materials in traditional permanent-magnet (PM) bias bearings cannot be adjusted, resulting in infl exible bearing performance. To improve the controllability of the PM bias fl ux in the integrated radial-axial magnetic bearing (RAMB), this article proposes a new design that uses a low coercivity AlNiCo magnet and equips a magnetization coil. By controlling the current of the magnetization coil, the magnetization state and bias fl ux of the AlNiCo magnet can be adjusted in situ, thereby improving the force characteristics and rotor iron losses of the PM-biased RAMB. The designed RAMB is analyzed and verifi ed by the 3D fi nite element method and the analytical model based on Preisach’s hysteresis theory and magnetic circuit method. The proposed design off ers a new idea for magnetic bearing structure and control.

Preparation and sinterability of submicron titanium carbide powders synthesized with phenolic resin as carbon source by carbothermal reduction

Huijuan Qiu,Hongkang Wei,Shifeng Ren,Lingjun Sun,Jia Li,Zihan Wang,Lin Zhao,Chang-an Wang,Zhipeng Xie 한양대학교 청정에너지연구소 2024 Journal of Ceramic Processing Research Vol.25 No.2

Titanium carbide powders were synthesized under an argon atmosphere using titanium dioxide and pyrolysis carbon derivedfrom pyrolyzed phenolic resin as raw materials. The effects of synthesis temperature, holding time, and C/Ti molar ratio onthe phase composition and morphology of the synthesized powders were investigated. The results show that the pyrolyzedphenolic resin at 1000 ℃ is a carbon source composed of amorphous and crystalline carbon. Increasing the C/Ti molar ratio ofthe mixed powder can reduce the content of titanium oxide impurity, indicating the improvement in the purity of TiC powder. In addition, the C/Ti molar ratio can also significantly affect the morphology of the synthesized TiC powders. SEM and EDSresults exhibit that the atomic content on the surface of TiC particles is closely correlated with the atomic distribution on thesurface of the particles. TiC powder with a median particle size of 384 nm could be synthesized at 1500 ℃ for 30 min at the C/Ti molar ratio of 2.3:1. In addition, the sinterability of the synthesized TiC powder was preliminarily discussed. The hardnessand fracture toughness of the TiC ceramic sintered at 2000 ℃ under 40 MPa with a dwell time of 2 h are 15.92 GPa and 3.22MPa·m1/2, respectively.