Graphene-supported SnO ₂ nanoparticles prepared by a solvothermal approach for an enhanced electrochemical performance in lithium-ion batteries

Wang, Bei,Su, Dawei,Park, Jinsoo,Ahn, Hyojun,Wang, Guoxiu Springer 2012 Nanoscale research letters Vol.7 No.1

<P>SnO<SUB>2</SUB> nanoparticles were dispersed on graphene nanosheets through a solvothermal approach using ethylene glycol as the solvent. The uniform distribution of SnO<SUB>2</SUB> nanoparticles on graphene nanosheets has been confirmed by scanning electron microscopy and transmission electron microscopy. The particle size of SnO<SUB>2</SUB> was determined to be around 5 nm. The as-synthesized SnO<SUB>2</SUB>/graphene nanocomposite exhibited an enhanced electrochemical performance in lithium-ion batteries, compared with bare graphene nanosheets and bare SnO<SUB>2</SUB> nanoparticles. The SnO<SUB>2</SUB>/graphene nanocomposite electrode delivered a reversible lithium storage capacity of 830 mAh g<SUP>−1</SUP> and a stable cyclability up to 100 cycles. The excellent electrochemical properties of this graphene-supported nanocomposite could be attributed to the insertion of nanoparticles between graphene nanolayers and the optimized nanoparticles distribution on graphene nanosheets.</P>

Fault detection based on polygon area statistics of transformation matrix identified from combined moving window data

Bei Wang,Xuefeng Yan,Yongfei Jin 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.2

Principal component analysis (PCA) has been widely used in monitoring industrial processes, but it is still necessary to make improvements in having a timely and effective access to variation information. It is known that the transformation matrix generated from real-time PCA model indicates inner relations between original variables and new produced components, so this matrix would be different when modeling data deviate due to the change of the operating condition. Based on this theory, this paper proposes a novel real-time monitoring approach which utilizes polygon area method to measure the variation degree of the transformation matrices and then constructs a statistic for monitoring purpose. The on-line data are collected through a combined moving window (CMW), containing both normal and monitored data. To evaluate the performance of the proposed method, a simple numerical simulation, the CSTR process and the classic Tennessee Eastman process are employed for illustration, with some PCA-based methods used for comparison.

Conditional Probability of Cauchy Distribution in Automatic Sleep Stage Determination for Sleep Data with Artifacts

Bei Wang,Takenao Sugi,Fusae Kawana,Xingyu Wang,Masatoshi Nakamura 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

An automatic sleep stage determination system dealing with the sleep data contaminated by artifacts is developed, which is working on an expert knowledge-based multi-valued decision making method. The knowledge database is consisted of probability density functions of parameters for various sleep stages according to the visual inspection by a qualified clinician. The probability density functions are approximated by Cauchy distribution on histograms. Sleep stages are determined automatically according to the maximum value of conditional probability. Due to the infinite variance of Cauchy distribution, the effect of mis-determination caused by artifacts can be abated. The result of automatic sleep stage determination was satisfactory. The presented automatic sleep stage determination can be an assistant tool for clinical practice.

H<SUB>∞</SUB> Consensus for Heterogeneous Multi-agent Systems with Time-delay

Bei-Bei Wang,Yuan-Gong Sun 제어로봇시스템학회 2014 제어로봇시스템학회 국제학술대회 논문집 Vol.2014 No.10

In this paper, we consider the consensus and H∞ consensus problems of heterogeneous multi-agent systems composed of first-order and second-order integrator agents in directed networks with time-delay. Based on the graph theory and the reduced-order transformation, we first rewrite the heterogeneous multi-agent systems into the corresponding reduced-order systems. Then, we study the consensus of the heterogeneous multi-agent system with time-delay by using the linear matrix inequality method. As a result, sufficient conditions for consensus and H∞ consensus of heterogeneous multi-agent systems in terms of linear matrix inequalities are established. Finally, simulation results are provided to demonstrate the effectiveness of the main theoretical results.

Elevated PIVKA-II is Associated with Early Recurrence and Poor Prognosis in BCLC 0-A Hepatocellular Carcinomas

Wang, Bei-Li,Tan, Qi-Wen,Gao, Xing-Hui,Wu, Jiong,Guo, Wei Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.16

Background: To investigate the prognostic value of serum PIVKA-II (prothrombin induced by the absence of vitamin K or antagonist-II) in BCLC (Barcelona Clinic Liver Cancer) 0-A hepatocellular carcinoma (HCC) patients after curative resection. Materials and Methods: Preoperative sera were collected from 140 patients with BCLC 0-A HCCs undergoing curative resection during 2011-2012 in Zhongshan Hospital. Follow-up ended on November 2013. ELISA was used to detect the serum concentrations of preoperative PIVKA-II. The prognostic value of PIVKA-II and other clinicopathological factors was analyzed by the Kaplan-Meier method and the multivariate Cox proportional hazards model. Results: During follow-up, 39 of 140 patients suffered recurrence and the 1-year recurrence rate was 27.9%. The high-PIVKA-II expression group had lower 1-year time to progression (TTP) compared with the low-expression group (54.8% vs 20.2%, p<0.001). Patients with high preoperative PIVKA-II expression showed a relatively higher risk of developing postoperative recurrence than those with low expression in the low-recurrence-risk subgroups, including ${\alpha}$-fetoprotein ${\leq}400ng/mL$ (45.4% vs 16.7%; p=0.006), tumor size ${\leq}5cm$ (54.2% vs 18.1%; p<0.001), single tumor (56.0% vs 19.1%; p<0.001), absence of satellite lesions (53.3% vs 19.8%; p=0.001), absence of vascular invasion (52.6% vs 14.9%; p=0.002), and Edmondson stage I/II (60.9% vs 20.3%; p<0.001). PIVKA-II was the strongest independent prognostic factor for TTP (hazard ratio, 2.877; 95% CI 1.524-5.429; p=0.001). Conclusions: Elevated PIVKA-II is associated with early recurrence of BCLC 0-A HCC after curative resection and can be considered a novel prognostic predictor.

Fault detection and identification using a Kullback-Leibler divergence based multi-block principal component analysis and bayesian inference

Bei Wang,Xuefeng Yan,Qingchao Jiang 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.6

Considering the huge number of variables in plant-wide process monitoring and complex relationships(linear, nonlinear, partial correlation, or independence) among these variables, multivariate statistical process monitoring(MSPM) performance may be deteriorated especially by the independent variables. Meanwhile, whether related variableskeep high concordance during the variation process is still a question. Under this circumstance, a multi-block technologybased on mathematical statistics method, Kullback-Leibler Divergence, is proposed to put the variables having similarstatistical characteristics into the same block, and then build principal component analysis (PCA) models in each lowdimensionalsubspace. Bayesian inference is also employed to combine the monitoring results from each sub-blockinto the final monitoring statistics. Additionally, a novel fault diagnosis approach is developed for fault identification. The superiority of the proposed method is demonstrated by applications on a simple simulated multivariate processand the Tennessee Eastman benchmark process.

Highly Ordered Mesoporous Cobalt Oxide Nanostructures: Synthesis, Characterisation, Magnetic Properties, and Applications for Electrochemical Energy Devices

Wang, Guoxiu,Liu, Hao,Horvat, Josip,Wang, Bei,Qiao, Shizhang,Park, Jinsoo,Ahn, Hyojun WILEY-VCH Verlag 2010 Chemistry Vol.16 No.36

<P>Highly ordered mesoporous Co<SUB>3</SUB>O<SUB>4</SUB> nanostructures were prepared using KIT-6 and SBA-15 silica as hard templates. The structures were confirmed by small angle X-ray diffraction, high resolution transmission electron microscopy, and N<SUB>2</SUB> adsorption–desorption isotherm analysis. Both KIT-6 cubic and SBA-15 hexagonal mesoporous Co<SUB>3</SUB>O<SUB>4</SUB> samples exhibited a low Néel temperature and bulk antiferromagnetic coupling due to geometric confinement of antiferromagnetic order within the nanoparticles. Mesoporous Co<SUB>3</SUB>O<SUB>4</SUB> electrode materials have demonstrated the high lithium storage capacity of more than 1200 mAh g<SUP>−1</SUP> with an excellent cycle life. They also exhibited a high specific capacitance of 370 F g<SUP>−1</SUP> as electrodes in supercapacitors.</P> <B>Graphic Abstract</B> <P>Highly ordered mesoporous Co<SUB>3</SUB>O<SUB>4</SUB> nanostructures have been prepared by using a hard-template method. Mesoporous Co<SUB>3</SUB>O<SUB>4</SUB> (general TEM image shown) exhibits a low Néel temperature and bulk antiferromagnetic coupling. When used as electrode materials in lithium-ion cells and supercapacitors, mesoporous Co<SUB>3</SUB>O<SUB>4</SUB> demonstrates a high reversible lithium storage capacity and a high specific supercapacitance. <img src='wiley_img_2010/09476539-2010-16-36-CHEM201000562-content.gif' alt='wiley_img_2010/09476539-2010-16-36-CHEM201000562-content'> </P>

Study on the Internal Pipeline Inspection Devices with Energy Acquisition Methods

Wang Ming-Xu,차인수,Wang Yue,Bei Lei,최홍준,정경환,김동묵,김봄,오승아,Ye In Cheol,유일준 한국에너지학회 2023 에너지공학 Vol.32 No.1

The pipeline conveying natural gas must be regularly inspected by the detection device, and the cracks and corrosion condition inside the pipeline should be detected. Generally, the detection device consists of three parts: drive part, detection part and energy part. Since pipeline transportation is long-distance transportation and cannot realize wired detection, the energy part needs to provide enough electric energy for the detection part to meet the energy consumption of the detection part. The method of obtaining energy for the energy part is very important. In this paper, the energy part is studied, and an efficient energy part is designed. By analyzing the change law of the positive pressure on the inner wall of the energy acquisition wheel on the pipeline, the corresponding torque and power changes are obtained when the detector moves at different speeds. Through the test platform system, the output power of the energy part at different speeds is collected, and the accuracy of the theoretical calculation is verified.

A Novel All-trans Retinoid Acid Derivative Induces Apoptosis in MDA-MB-231 Breast Cancer Cells

Wang, Bei,Yan, Yun-Wen,Zhou, Qing,Gui, Shu-Yu,Chen, Fei-Hu,Wang, Yuan Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.24

Aims: To explore the effect and probable mechanism of a synthetic retinoid 4-amino-2-tri-fluoromethylphenyl ester (ATPR) on apoptosis of MDA-MB-231 breast cancer cells. Materials and Methods: MTT assays were performed to measure the proliferation of MDA-MB-231 cells treated with different concentrations of all-trans retinoic acid (ATRA) and ATPR. Morphologic changes were observed by microscopy. The apoptosis rates and cell cycling of MDA-MB-231 cells treated with ATRA or ATPR were assessed using flow cytometry analysis. Expression of retinoic acid receptor and phosphorylation of ERK, JNK, p38 proteins were detected by Western blotting. Results: Treatment of the cells with the addition of $15{\mu}mol/L$ ATPR for 48 h clearly demonstrated reduced cell numbers and deformed cells, whereas no changes in the number and morphology were observed after treatment with ATRA. The apoptosis rate was 33.2% after breast cancer MDA-MB-231 cells were treated by ATPR ($15{\mu}mol/L$) whereas ATRA ($15{\mu}mol/L$) had no apoptotic effect. ATPR inhibited the phosphorylation of ERK, JNK, and p38 while ATRA had no significant effect. ATPR inhibited the expression of BiP and increased the expression of Chop at the protein level compared with control groups, ATRA and ATPR both decreased the protein expression of $RXR{\alpha}$, ATPR reduced the protein expression of $RAR{\beta}$ and $RXR{\beta}$ while ATRA did not decrease $RAR{\beta}$ or $RXR{\beta}$. Conclusions: ATPR could induce apoptosis of breast cancer MDA-MB-231 cells, possible mechanisms being binding to $RAR{\beta}/RXR{\beta}$ heterodimers, then activation of ER stress involving the MAPK pathway.

Automatic Sleep Stage Determination for Sleep Apnea Syndrome Patients

Bei Wang,Takenao Sugi,Fusae Kawana,Xingyu Wang,Masatoshi Nakamura 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

In this study, the multivariate probability distribution was investigated to develop the expert knowledge-based automatic sleep stage determination technique. The ultimate purpose is to develop adaptive automatic sleep stage deter-mination algorithm for clinical practice. Gaussi and is tribution was adopted to realize automatic parameter selection while Cauchy distribution was a dopted to estimate the parameter distriution. The different usage of multivariate probability distribution of Gaussian and Cauchy distribution presented effectiveness for automatic sleep stage determination.