A COST-EFFECTIVE MAGNETIC PHOTOCATALYST PALYGORSKITE – TiO 2 – Fe x O y WITH EXCELLENT PERFORMANCE FOR DYE PHOTODEGRADATION UNDER VISIBLE LIGHT

JIAHUI ZHANG,Lili Zhang,JIN HUANG,Shouyong Zhou,Haiqun Chen,WEIGUANG ZHANG,Xin Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.6

Palygorskite (denoted as Pal) was used as an economical carrier of hybrid photocatalystTiO 2 – FexOy via an in situ depositing technique (marked as Pal – TiO 2 – FexOy). The samples werecharacterized by X-ray di®raction (XRD), transmission electron microscopy (TEM), brunner-emmet-teller (BET) measurements, X-ray photoelectron spectroscopy (XPS) and UV-Vis di®usere°ectance spectra measurements. Results showed that TiO 2 – FexOy composite particles withaverage size of about 10 nm were loaded onto the Pal ¯bers' surface. FexOy acted not only asmagnetic source but also took part in the formation of TiO 2 – FexOy heterojunction structure, which resulted in the obvious absorption in visible light region for the obtained Pal – TiO 2 – FexOy com-posite photocatalyst. The obtained Pal – TiO 2 – FexOy shows excellent photocatalytic activity to-ward photodegradation of Methyl orange (MO) under visible light irradiation and the degradationratio reached 94% within 180 min. Moreover, Pal – TiO 2 – FexOy could be readily recovered from thereaction solution by the magnet. Possible mechanism for the enhancement was also proposed.

Magnetically separable attapulgite−TiO2−FexOy composites with superior activity towards photodegradation of methyl orange under visible light radiation

Jiahui Zhang,Lili Zhang,Shouyong Zhou,Haiqun Chen,Hui Zhong,Yijiang Zhao,Xin Wang 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

A magnetically recoverable composite photocatalyst was obtained by introducing TiO2–FexOy hybrid oxide onto the surface of attapulgite via an in-situ deposit technique (marked as ATT–TiO2–FexOy-r, r represents molar ratio of r = nTi/(nTi + nFe)). The obtained composites were carefully characterized and results showed TiO2–FexOy particles with an average size of 10 nm were successfully loaded onto attapulgite fibers’ surface. The FexOy (mixture of Fe2O3 and Fe3O4) acted not only as magnetic source but also took part in the formation of TiO2–Fe2O3 heterojunction structure, which resulted in the obvious absorption in visible light region for the obtained ATT–TiO2–FexOy. The obtained ATT–TiO2–FexOy-r exhibited quite good catalytic activity towards photodegradation of methyl orange under visible light irradiation. The highest degradation ratio and COD removal of methyl orange reached to 94.13% and 90.91% for ATT–TiO2–FexOy-0.5. Moreover, ATT–TiO2–FexOy could be readily recovered and the degradation ratio maintains 83.89% after 5 cycles. Possible mechanism for this enhancement was proposed.

PLI-VIO: Real-time Monocular Visual-inertial Odometry Using Point and Line Interrelated Features

Jiahui Zhang,Qingzhen Shang,Jinfu Yang,Mingai Li 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.6

As a popular technology, visual-inertial odometry (VIO) has been widely applied in many fields such as autonomous robots and unmanned aerial vehicle (UAV). However, the trade-off between localization accuracy and real-time performance still needs to be optimized. This paper presents a real-time tightly-coupled monocular VIO system using point and line interrelated features (PLI-VIO) under the sliding window optimization framework. In line feature extraction part of PLI-VIO, a line segment extraction and coalescence algorithm based on EDlines is proposed, which extracts line features in real-time without concession on feature quality. At the same time, in order to get efficient and robust line tracking effect, PLI-VIO presents a line-to-point tracking method that fully utilizes the interrelation between point and line. Specifically, line features are divided as a group of points and tracked by pyramidal implementation of Lucas Kanade feature tracker. The proposed line feature tracking method can effectively reduce time consumption on tracking process in a robust way. Extensive evaluations on Euroc and TUM-VI public datasets are performed to demonstrate the preferable performance of our proposed system, and the results show that PLI-VIO obtains better localization accuracy with less computation cost compared against other state-of-the-art VIO algorithms.

Reduced-order Mapping and Design-oriented Instability for Constant On-time Current-mode Controlled Buck Converters with a PI Compensator

Zhang, Xi,Xu, Jianping,Wu, Jiahui,Bao, Bocheng,Zhou, Guohua,Zhang, Kaitun The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.5

The constant on-time current-mode controlled (COT-CMC) switching dc-dc converter is stable, with no subharmonic oscillation in its current loop when a voltage ripple in its outer voltage loop is ignored. However, when its output capacitance is small or its feedback gain is high, subharmonic oscillation may occur in a COT-CMC buck converter with a proportional-integral (PI) compensator. To investigate the subharmonic instability of COT-CMC buck converters with a PI compensator, an accurate reduced-order asynchronous-switching map model of a COT-CMC buck converter with a PI compensator is established. Based on this, the instability behaviors caused by output capacitance and feedback gain are investigated. Furthermore, an approximate instability condition is obtained and design-oriented stability boundaries in different circuit parameter spaces are yielded. The analysis results show that the instability of COT-CMC buck converters with a PI compensator is mainly affected by the output capacitance, output capacitor equivalent series resistance (ESR), feedback gain, current-sensing gain and constant on-time. The study results of this paper are helpful for the circuit parameter design of COT-CMC switching dc-dc converters. Experimental results are provided to verify the analysis results.

Reduced-order Mapping and Design-oriented Instability for Constant On-time Current-mode Controlled Buck Converters with a PI Compensator

Xi Zhang,Jianping Xu,Jiahui Wu,Bocheng Bao,Guohua Zhou,Kaitun Zhang 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.5

The constant on-time current-mode controlled (COT-CMC) switching dc-dc converter is stable, with no subharmonic oscillation in its current loop when a voltage ripple in its outer voltage loop is ignored. However, when its output capacitance is small or its feedback gain is high, subharmonic oscillation may occur in a COT-CMC buck converter with a proportional-integral (PI) compensator. To investigate the subharmonic instability of COT-CMC buck converters with a PI compensator, an accurate reduced-order asynchronous-switching map model of a COT-CMC buck converter with a PI compensator is established. Based on this, the instability behaviors caused by output capacitance and feedback gain are investigated. Furthermore, an approximate instability condition is obtained and design-oriented stability boundaries in different circuit parameter spaces are yielded. The analysis results show that the instability of COT-CMC buck converters with a PI compensator is mainly affected by the output capacitance, output capacitor equivalent series resistance (ESR), feedback gain, current-sensing gain and constant on-time. The study results of this paper are helpful for the circuit parameter design of COT-CMC switching dc-dc converters. Experimental results are provided to verify the analysis results.

A fault diagnosis method using Interval coded deep belief network

Jiahui Tang,Jimei Wu,Bingbing Hu,Chang Guo,Jialing Zhang 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.5

The rolling bearing, though a widely used component in rotating machinery, is also failure-prone. There are some difficulties in extracting valuable fault features from the vibration signal generated by the rolling bearing operation. Based on the interval coded deep belief network, an improved method for fault diagnosis is introduced to deal with the existing problems. Interval code is an encoding method to characterize fault features by using bearing vibration amplitude distribution. This method can also reduce the complexity of the original data and integrate input dimension. The deep belief network can remove the dependence from manual feature extraction and quickly extract the fault features from coding results. This proposed method is employed in the fault diagnosis experiments of rolling bearing to evaluate the performance. From the obtained experiment results, it can be concluded that the interval coded deep belief network boosts performance, which can eliminate the limitation of the input data dimension in the traditional deep learning model.

3D Bioprinted GelMA/PEGDA Hybrid Scaffold for Establishing an In Vitro Model of Melanoma

( Jiahui Duan ),( Yanyan Cao ),( Zhizhong Shen ),( Yongqiang Cheng ),( Zhuwei Ma ),( Lijing Wang ),( Yating Zhang ),( Yuchuan An ),( Shengbo Sang ) 한국미생물생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.4

Due to the high incidence of malignant melanoma, the establishment of in vitro models that recapitulate the tumor microenvironment is of great biological and clinical importance for tumor treatment and drug research. In this study, 3D printing technology was used to prepare GelMA/PEGDA composite scaffolds that mimic the microenvironment of human malignant melanoma cell (A375) growth and construct in vitro melanoma micro-models. The GelMA/PEGDA hybrid scaffold was tested by the mechanical property, cell live/dead assay, cell proliferation assay, cytoskeleton staining and drug loading assay. The growth of tumor cells in two- and three-dimensional culture systems and the anti-cancer effect of luteolin were evaluated using the live/dead staining method and the Cell Counting Kit-8 (CCK-8) method. The results showed a high aggregation of tumor cells on the 3D scaffold, which was suitable for long-term culture. Cytoskeleton staining and immunofluorescent protein staining were used to evaluate the degree of differentiation of tumor cells under 2D and 3D culture systems. The results indicated that 3D bioprinted scaffolds were more suitable for tumor cell expansion and differentiation, and the tumor cells were more aggressive. In addition, luteolin was time- and dose-dependent on tumor cells, and tumor cells in the 3D culture system were more resistant to the drug.

HS-Sign: A Security Enhanced UOV Signature Scheme Based on Hyper-Sphere

( Jiahui Chen ),( Shaohua Tang ),( Xinglin Zhang ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.6

For “generic” multivariate public key cryptography (MPKC) systems, experts believe that the Unbalanced Oil-Vinegar (UOV) scheme is a feasible signature scheme with good efficiency and acceptable security. In this paper, we address two problems that are to find inversion solution of quadratic multivariate equations and find another structure with some random Oil-Oil terms for UOV, then propose a novel signature scheme based on hyper-sphere (HS-Sign for short) which directly answers these two problems. HS-Sign is characterized by its adding Oil-Oil terms and more advantages compared to UOV. On the one side, HS-Sign is based on a new inversion algorithm from hyper-sphere over finite field, and is shown to be a more secure UOV-like scheme. More precisely, according to the security analysis, HS-Sign achieves higher security level, so that it has larger security parameters choice ranges. On the other side, HS-Sign is beneficial from both the key side and computing complexity under the same security level compared to many baseline schemes. To further support our view, we have implemented 5 different attack experiments for the security analysis and we make comparison of our new scheme and the baseline schemes with simulation programs so as to show the efficiencies. The results show that HS-Sign has exponential attack complexity and HS-Sign is competitive with other signature schemes in terms of the length of the message, length of the signature, size of the public key, size of the secret key, signing time and verification time.

A State-of-Health Estimation and Prediction Algorithm for Lithium-Ion Battery of Energy Storage Power Station Based on Information Entropy of Characteristic Data

Yue Jiahui,Xia Xiangyang,Zhang Yuan,Xia Tian 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.3

In order to enrich the comprehensive estimation methods for the balance of battery clusters and the aging degree of cells for lithium-ion energy storage power station, this paper proposes a state-of-health estimation and prediction method for the energy storage power station of lithium-ion battery based on information entropy of characteristic data. This method optimizes and processes attribute data based on specific running segments to form a characteristic data set, and adopts the information entropy value to reflect the orderliness of characteristic data to analyze the balance of battery clusters and the aging degree of cells in it. At the same time, the BP neural network is used to predict the information entropy value to achieve short-term prediction of the station’s health state. The feasibility and effectiveness of the health state estimation and prediction method proposed in this paper are demonstrated using actual data collected from the lithium-ion battery testing platform and the energy storage power station.

Inhibition of BETs prevents heat shock-induced cell death via upregulating HSPs in SV40 large T antigen transfected cells

Zhou Nan,Zhang Ye,Lei Gongyun,Chen Yifan,Lin Ting,Liu Qin,Zhao Yinshuang,Mao Jiahui,Jiang Yongying,Mao Renfang 한국유전학회 2022 Genes & Genomics Vol.44 No.10

Background: Heat shock response is a protected mechanism against environmental changes for the organism, which must be tightly regulated. Bromodomain and extra terminal-containing protein family (BETs) regulate numerous gene expression in many physiological and pathological conditions, including viral infection. SV40 is considered as a highly human disease-associated virus. Objective: We aimed to explore whether BETs play a role in heat shock in SV40 large T antigen transfected cells. Methods: SV40LTA was transfected in HeLa cells using the Lipofectamine 8000. BETs inhibitor JQ1 and I-BET-762 was employed to treat transfected cells and HEK-293 T cells. Heat shock treatment was performed to determine the effect of JQ1 and I-BET-762 on these cells. Western blot and quantitative RT-PCR were carried out to assess the expression of HSP70 and other HSPs. Results: We found that inhibition of BETs by JQ1 and I-BET-762 protects cells from heat shock-induced death in HEK293T cells. Both JQ1 and I-BET-762 induce the expression of HSPs and HSF1 in HEK-293 T cells. However, neither JQ1 nor I-BET-762 fail to induce the expression of HSPs in either HeLa or HBL-1 cells. When SV40 large T antigen was transfected into HeLa cells, the induction of HSP70 expressing and the protection of heat shock-induced cell death are reproduced by JQ1 and IBET treatment in these transfected cells. Conclusions: Inhibition of BETs by JQ1 and I-BET-762 prevents heat shock-induced cell death via upregulating HSPs in SV40 large T antigen transfected cells. Our data indicate a novel function of BETs in SV40 large T antigen transformed cells, affecting HSPs and HSF1 as well as its function on heat shock response.