Polyaniline/Fe composite nanofiber added softmagnetic carbonyl iron microsphere suspension and its magnetorheology

Piao, Shang Hao,Bhaumik, Madhumita,Maity, Arjun,Choi, Hyoung Jin The Royal Society of Chemistry 2015 Journal of Materials Chemistry C Vol.3 No.8

<P>Fe<SUP>0</SUP>nanoparticle-supported polyaniline (PANI) composite nanofibers were prepared as an additive for carbonyl iron (CI)-based magnetorheological (MR) fluids to improve the MR properties and dispersion stability. A simple chemical strategy was adopted to synthesize the PANI/Fe<SUP>0</SUP>composite nanofibers. The synthesis method was based on the initial fabrication of interconnected PANI nanofibers by a rapidly mixed polymerization process using ferric chloride (FeCl3) as the oxidant and the subsequent reductive support of Fe<SUP>0</SUP>nanoparticles onto the PANI nanofiber matrix using the polymerization by-products as a metal precursor. X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy showed that the fabricated nanofibers were composed of PANI and Fe<SUP>0</SUP>. Scanning and transmission electron microscopy imaging confirmed that the PANI/Fe<SUP>0</SUP>composite nanofibers were 80-150 nm in diameter with an interconnected matrix. The MR fluid with the PANI/Fe<SUP>0</SUP>composite nanofibers dispersed in mineral oil under an external magnetic field showed enhanced MR properties compared to that without an additive. Turbiscan data also confirmed the improved sedimentation properties of the MR fluid with an additive.</P>

Influence of Water Absorption and Temperature on the Mechanical Properties of Discontinuous Carbon Fiber Reinforced Polyamide 6

Hao Piao,Lubai Chen,Yoshiaki Kiryu,Isamu Ohsawa,Jun Takahashi 한국섬유공학회 2019 Fibers and polymers Vol.20 No.3

Carbon fiber reinforced thermoplastics (CFRTP) show relatively high mechanical properties and are expected tobe feasible materials for mass production of light-weight structures. In particular, discontinuous CFRTP (DCFRTP) with affordable resins have been developed to realize excellent formability and mechanical properties. Currently, polyamide 6 (PA6) is a promising matrix for CFRTP in mass-produced automobiles. However, due to the hygroscopic and viscoelastic properties of polyamide resins, the influence of water absorption on the mechanical properties of CFRTP under varying temperature is necessary to be investigated. In this study, the influence of water absorption on the mechanical properties of discontinuous CF/PA6 composites was investigated. Chopped carbon fiber tape reinforced thermoplastics (CTT), which are randomly oriented strand (ROS) composites, were selected as DCFRTP. The mechanical properties of the composites were investigated by a three point bending test between -40 and 125 oC, as a function of water absorption. The flexural modulus were calculated using the Timoshenko beam equation to predict degradation by water absorption. The mechanical properties of CTT have a relatively high sensitivity to water absorption.

Virtual Environment Modeling for Battery Management System

Piao, Chang-Hao,Yu, Qi-Fan,Duan, Chong-Xi,Su, Ling,Zhang, Yan The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

The offline verification of state of charge estimation, power estimation, fault diagnosis and emergency control of battery management system (BMS) is one of the key technologies in the field of electric vehicle battery system. It is difficult to test and verify the battery management system software in the early stage, especially for algorithms such as system state estimation, emergency control and so on. This article carried out the virtual environment modeling for verification of battery management system. According to the input/output parameters of battery management system, virtual environment is determined to run the battery management system. With the integration of the developed BMS model and the external model, the virtual environment model has been established for battery management system in the vehicle's working environment. Through the virtual environment model, the effectiveness of software algorithm of BMS was verified, such as battery state parameters estimation, power estimation, fault diagnosis, charge and discharge management, etc.

Benefits of Statin Therapy in Patients With Acute Myocardial Infarction With Serum Low-Density Lipoprotein Cholesterol ≤ 50 mg/dl

Piao, Zhe Hao,Jin, Li,Kim, Ju Han,Ahn, Youngkeun,Kim, Young Jo,Cho, Myeong Chan,Kim, Chong Jin,Kim, Hyo Soo,Liu, Bin,Jeong, Myung Ho Elsevier 2017 The American journal of cardiology Vol.120 No.2

<P>Previous trials have found that statin therapy reduces low-density lipoprotein cholesterol (LDL-C) level and the risk of cardiovascular events. However, the benefit of statin therapy in patients with baseline LDL-C levels ≤ 50 mg/dl is less clear. Therefore, the aim of this study was to assess whether patients with acute myocardial infarction (AMI) who have baseline LDL-C levels ≤ 50 mg/dl would benefit from statin therapy in real-world clinical practice. We analyzed the clinical data of 1,048 patients (67.3 ± 12.6 years, 69.6% men) with AMI, who had baseline LDL-C levels ≤ 50 mg/dl from the Korean Acute Myocardial Infarction Registry data between November 2005 and May 2014. They were divided into 2 groups based on whether they were prescribed statins or not at discharge (statin and nonstatin group, n = 738 and 310, respectively). The primary end point was the major adverse cardiac event (MACE), defined as the composite of all-cause mortality, recurrent myocardial infarction, and repeated percutaneous coronary intervention or coronary artery bypass grafting. MACE occurred in 9.2% of the statin group versus 19.6% in the nonstatin group during the 12-month follow-up. Statin therapy significantly reduced the risk of MACE (hazard ratio [HR] 0.60, 95% CI 0.39 to 0.94, p = 0.025) and coronary artery bypass grafting (HR 0.27, 95% CI 0.08 to 0.96, p = 0.043). There was a trend of reduced cardiac death in the statin group compared with the nonstatin group (HR 0.52, 95% CI 0.26 to 1.02, p = 0.059). Statin therapy for patients with AMI with LDL-C levels ≤ 50 mg/dl was associated with improved outcomes. Therefore, statin therapy is feasible and effective, even in AMI patients with extremely low levels of LDL-C.</P>

Dispersion state and rheological characteristics of carbon nanotube suspensions

Piao, Shang Hao,Kim, Min Hwan,Choi, Hyoung Jin,Lee, Hyeonju,Park, Jaehoon Elsevier 2017 Journal of industrial and engineering chemistry Vol.52 No.-

<P><B>Abstract</B></P> <P>We prepared carbon nanotube (CNT) suspensions with a fixed CNT concentration dispersed in <I>N</I>-methyl-2-pyrrolidone containing a dispersion agent to study dispersion stability of CNTs. Surface morphology and thickness of the CNT films fabricated via spin-coating were measured by an optical microscope and high-resolution scanning electron microscope, respectively. Furthermore, light transmittance measurements were performed using a transmission densitometer. Rheological behaviors measured using a rotational rheometer showed that while the ball-milled CNT suspensions showed better dispersion stability compared to the ‘pre-milling’ suspension, the dispersion stability depended on the milling time, with the effectiveness decreasing when the time increased above an optimal value.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A spin-coating process was applied for the analysis of dispersion stability of CNT suspensions along with rheology. </LI> <LI> Effect of different mixing condition of shear mixing and ball-milling technique on CNT suspensions were focused. </LI> <LI> CNT suspension at a given composition ratio between CNT and dispersion agent shows a good dispersion stability at an optimized ball-milling time. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Carbon nanotube (CNT) suspensions were prepared with a fixed CNT concentration dispersed in <I>N</I>-methyl-2-pyrrolidone containing a dispersion agent using a combination of shear mixing and ball-milling methods. To investigate the dispersibility of CNTs, we examined their rheological behaviors using a rotational rheometer, and used a spin-coating process to analyze the surface morphology and thickness of CNT films to support the rheological measurements.</P> <P>[DISPLAY OMISSION]</P>

Celebrating <i>Soft Matter</i>'s 10th Anniversary: Stimuli-responsive Pickering emulsion polymerized smart fluids

Piao, Shang Hao,Kwon, Seung Hyuk,Zhang, Wen Ling,Choi, Hyoung Jin The Royal Society of Chemistry 2015 SOFT MATTER Vol.11 No.4

<P>The Pickering emulsion process is an important and interesting way of forming hybrid soft matter particles stabilized by solid particles as surfactants instead of the extensive use of conventionally available organic surfactant molecules. This Highlight briefly reviews stimuli-responsive polymer/inorganic hybrid materials fabricated by Pickering emulsion polymerization along with the rheological characteristics of their electrorheological and magnetorheological smart fluids under electric and magnetic fields, respectively.</P> <P>Graphic Abstract</P><P>In this Highlight, we review the stimuli-responsive electrorheological and magnetorheological performance of Pickering emulsion-polymerized core–shell structured particle based smart fluids. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4sm02393e'> </P>

A Novel Battery State of Health Estimation Method Based on Outlier Detection Algorithm

Piao, Chang-hao,Hu, Zi-hao,Su, Ling,Zhao, Jian-fei The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.6

A novel battery SOH estimation algorithm based on outlier detection has been presented. The Battery state of health (SOH) is one of the most important parameters that describes the usability state of the power battery system. Firstly, a battery system model with lifetime fading characteristic was established, and the battery characteristic parameters were acquired from the lifetime fading process. Then, the outlier detection method based on angular distribution was used to identify the outliers among the battery behaviors. Lastly, the functional relationship between battery SOH and the outlier distribution was obtained by polynomial fitting method. The experimental results show that the algorithm can identify the outliers accurately, and the absolute error between the SOH estimation value and true value is less than 3%.

Experiment Study and Finite Element Analysis of Spring Constant of Welded Metal Bellows

Piao, Chang Hao,Cho, Chong Du,Kim, Chang Boo,Pang, Qiang Trans Tech Publications, Ltd. 2006 Key Engineering Materials Vol.326 No.-

<P>This study tries to obtain the spring constant of welded metal bellows through experimental and numerical method respectively. The prediction of spring constant plays a great role in the design and application of the welded metal bellows. To derive the spring constant of the bellows, we employ commercial package to build up 2 axi-symmetric FEM models by using plane 42 and shell 51 elements. In the experiment, we use UTM to measure the spring constant of the bellows. And, the predicted spring constant resulting from the analysis is compared with the experimental one to discuss the rationality of spring constant analysis. The analytical results correspond well with experimental data and hence explaining the validity of FEM model.</P>

Modeling and Implementation of Fixed Switching Frequency Sliding Mode Control to Two-Stage DC-DC Converter

Chang-hao Piao,Chao Jiang,Hongtao Qiao,조종두,Sheng Lu 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.6

A fixed switching frequency sliding mode (FSFSM) controller for two-stage DC-DC converter is proposed. Owing to the time-varying switched mode operation, the dynamic performance of two-stage converter becomes high order and non-linear. For designing the FSFSM controller, the state-space average model is made, and then the three conditions of sliding mode (SM) control, namely, hitting, existence and stability condition are analyzed. A conventional linear controller (Lag) for two-stage converter is designed as a comparison to validate the good robustness and dynamic response of the FSFSM controller. At last, a series of simulation and experimental results are presented to demonstrate the feasibility of the designed FSFSM controller.

Coronary Artery Fistula with Giant Aneurysm and Coronary Stenosis Treated by Transcatheter Embolization and Stent

Zhe Hao Piao,정명호,정해창,박근호,심두선,홍영준,김주한,안영근 대한심장학회 2015 Korean Circulation Journal Vol.45 No.3

Coronary artery fistula (CAF) with giant aneurysm and accompanied by coronary artery stenosis is a very rare disease. Herein, we report a case of a 76-year-old woman having a complex coronary-to-pulmonary artery fistula associated with a giant aneurysm and accompanied by coronary artery stenosis. The patient was successfully treated using transcatheter coil embolization and coronary stent implantation. Eight years later, we performed a follow-up coronary angiogram, which revealed the CAF and the aneurysm were completely occluded and previous stent patency