Intelligent Reconfigurable Surface enhanced Ambient Backscatter Communication enabled Wireless Body Area Network

Zhao Xu,Zang Weilin,Li Ye 한국통신학회 2023 ICT Express Vol.9 No.6

This paper considers an Intelligent Reconfigurable Surface (IRS)-enhanced Ambient Backscatter Communication (AmBC)-enabled Wireless Body Area Network (WBAN) system. We study the Base Station (BS) transmit power minimization problem, where the BS’s transmit beamforming vector and IRS’s reflecting coefficients are jointly optimized, subjected to the Signal-to-Noise Ratio (SNR) requirements of intra-WABN communication and throughput requirement of primary communication. To solve the non-convex problem, a near-optimal algorithm based on Semi-Definite Relaxation (SDR) and Successive Convex Approximation (SCA), and a low complexity algorithm based on IRS elements partition are proposed. Numerical results show that the two proposed algorithms considerably outperform the baseline schemes.

Synthesis and Characterization of Biodegradable Thermo- and pH-Sensitive Hydrogels Based on Pluronic F127/Poly($\varepsilon$-caprolactone) Macromer and Acrylic Acid

Zhao, Sanping,Cao, Mengjie,Wu, Jun,Xu, Weilin The Polymer Society of Korea 2009 Macromolecular Research Vol.17 No.12

Several kinds of biodegradable hydrogels were prepared via in situ photopolymerization of Pluronic F127/poly($\varepsilon$-caprolactone) macromer and acrylic acid (AA) comonomer in aqueous medium. The swelling kinetics measurements showed that the resultant hydrogels exhibited both thermo- and pH-sensitive behaviors, and that this stimuli-responsiveness underwent a fast reversible process. With increasing pH of the local buffer solutions, the pH sensitivity of the hydrogels was increased, while the temperature sensitivity was decreased. In vitro hydrolytic degradation in the buffer solution (pH 7.4, $37^{\circ}C$), the degradation rate of the hydrogels was greatly improved due to the introduction of the AA comonomer. The in vitro release profiles of bovine serum albumin (BSA) in-situ embedded into the hydrogels were also investigated: the release mechanism of BSA based on the Peppas equation was followed Case II diffusion. Such biodegradable dual-sensitive hydrogel materials may have more advantages as a potentially interesting platform for smart drug delivery carriers and tissue engineering scaffolds.

Numerical study of a two-stage turbine characteristic under pulsating flow conditions

Rongchao Zhao,Weilin Zhuge,Yangjun Zhang,Mingyang Yang,Ricardo Martinez-Botas 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.2

With developments of turbo-compounding and two-stage turbocharging technologies, two-stage turbine is increasingly applied in automotive engines. This paper numerically investigates the characteristic of a two-stage turbine on a turbo-compound engine under pulsating flow conditions. The behaviors of turbine stages with the swallowing capacity ratio (SR) equals to 2.0, under low, mid and high load conditions were studied. Results show that the Low pressure turbine (LPT) is more sensitive to the pulsating flow, especially at low load conditions, compared with High pressure turbine (HPT). It is caused by the dramatic change of velocity ratio in LPT. Results also show that the load split between HPT and LPT under pulsating flow conditions deviates from that at quasi-steady conditions, indicating the different behaviors of the two-stage turbine under pulsating conditions.

Optical Design of a Snapshot Nonmydriatic Fundus-imaging Spectrometer Based on the Eye Model

Xuehui Zhao,Jun Chang,Wenchao Zhang,Dajiang Wang,Weilin Chen,Jiajing Cao 한국광학회 2022 Current Optics and Photonics Vol.6 No.2

Fundus images can reflect ocular diseases and systemic diseases such as glaucoma, diabetes mellitus, and hypertension. Thus, research on fundus-detection equipment is of great importance. The fundus camera has been widely used as a kind of noninvasive detection equipment. Most existing devices can only obtain two-dimensional (2D) retinal-image information, yet the fundus of the human eye also has spectral characteristics. The fundus has many pigments, and their different distributions in the eye lead to dissimilar tissue penetration for light waves, which can reflect the corresponding fundus structure. To obtain more abundant information and improve the detection level of equipment, a snapshot nonmydriatic fundus imaging spectral system, including fundus-imaging spectrometer and illumination system, is studied in this paper. The system uses a microlens array to realize snapshot technology; information can be obtained from only a single exposure. The system does not need to dilate the pupil. Hence, the operation is simple, which reduces its influence on the detected object. The system works in the visible and near-infrared bands (550–800 nm), with a volume less than 400 mm × 120 mm × 75 mm and a spectral resolution better than 6 nm.

An investigation on the performance of a Brayton cycle waste heat recovery system for turbocharged diesel engines

Binyang Song,Weilin Zhuge,Rongchao Zhao,Xinqian Zheng,Yangjun Zhang,Yong Yin,Yanting Zhao 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.6

A Brayton cycle waste heat recovery (WHR) system for turbocharged diesel engines was proposed and the performance of a diesel engine integrated with the proposed system was investigated. The waste heat recovery system is integrated with the turbocharging system of diesel engines, using the turbocharger compressor as the Brayton cycle compressor. The engine cycle simulation code GT-Suite 7.0was used to investigate the performance of a diesel engine integrated with the WHR system. A Brayton cycle turbine was designed and its performance was simulated with a through-flow model. The turbocharging system of the original engine was modified and the energy flow distribution between the diesel cycle and the Brayton cycle was optimized. Results show that the fuel economy of the diesel engine can be improved by 2.6% at high engine speed and 4.6% at low engine speed under engine full load operating conditions when equipped with the Brayton cycle WHR system. The influence of turbocharger parameters on the WHR engine performance was invesgated.

Experimental study on the performance of a turbocompound diesel engine with variable geometry turbocharger

Yong Yin,Zhengbai Liu,Weilin Zhuge,Rongchao Zhao,Yanting Zhao,Zhen Chen,Jiao Mi 한국유체기계학회 2016 International journal of fluid machinery and syste Vol.9 No.4

Turbocompounding is a key technology to satisfy the future requirements of diesel engine’s fuel economy and emission reduction. A turbocompound diesel engine was developed based on a conventional 11-Liter heavy-duty diesel engine. The turbocompound system includes a power turbine, which is installed downstream of a Variable Geometry Turbocharger (VGT) turbine. The impacts of the VGT rack position on the turbocompound engine performance were studied. An optimal VGT control strategy was determined. Experimental results show that the turbocompound engine using the optimal VGT control strategy achieves better performance than the original engine under all full load operation conditions. The averaged and maximum reductions of the brake specific fuel consumption (BSFC) are 3% and 8% respectively.

Experimental study on the performance of a turbocompound diesel engine with variable geometry turbocharger

Yin, Yong,Liu, Zhengbai,Zhuge, Weilin,Zhao, Rongchao,Zhao, Yanting,Chen, Zhen,Mi, Jiao Korean Society for Fluid machinery 2016 International journal of fluid machinery and syste Vol.9 No.4

Turbocompounding is a key technology to satisfy the future requirements of diesel engine's fuel economy and emission reduction. A turbocompound diesel engine was developed based on a conventional 11-Liter heavy-duty diesel engine. The turbocompound system includes a power turbine, which is installed downstream of a Variable Geometry Turbocharger (VGT) turbine. The impacts of the VGT rack position on the turbocompound engine performance were studied. An optimal VGT control strategy was determined. Experimental results show that the turbocompound engine using the optimal VGT control strategy achieves better performance than the original engine under all full load operation conditions. The averaged and maximum reductions of the brake specific fuel consumption (BSFC) are 3% and 8% respectively.

Optical Super-Resolution Imaging of Surface Reactions

Chen, Tao,Dong, Bin,Chen, Kuangcai,Zhao, Fei,Cheng, Xiaodong,Ma, Changbei,Lee, Seungah,Zhang, Peng,Kang, Seong Ho,Ha, Ji Won,Xu, Weilin,Fang, Ning American Chemical Society 2017 Chemical reviews Vol.117 No.11

<P>Optical super-resolution imaging has gained momentum in investigations of heterogeneous and homogeneous chemical reactions at the single-molecule level. Thanks to its exceptional spatial resolution and ability to monitor dynamic systems, much detailed information on single-molecule reaction/adsorption processes and single-particle catalytic processes has been revealed, including chemical kinetics and reaction dynamics; active-site distributions on single-particle surfaces; and size-, shape-, and facet-dependent catalytic activities of individual nanocatalysts. In this review, we provide an overview of recent advances in super-resolution chemical imaging of surface reactions.</P>

Prediction of Pharmacokinetics and Penetration of Moxifloxacin in Human with Intra-Abdominal Infection Based on Extrapolated PBPK Model

Zhu, LiQin,Yang, JianWei,Zhang, Yuan,Wang, YongMing,Zhang, JianLei,Zhao, YuanYuan,Dong, WeiLin The Korean Society of Pharmacology 2015 The Korean Journal of Physiology & Pharmacology Vol.19 No.2

The aim of this study is to develop a physiologically based pharmacokinetic (PBPK) model in intra-abdominal infected rats, and extrapolate it to human to predict moxifloxacin pharmacokinetics profiles in various tissues in intra-abdominal infected human. 12 male rats with intra- abdominal infections, induced by Escherichia coli, received a single dose of 40 mg/kg body weight of moxifloxacin. Blood plasma was collected at 5, 10, 20, 30, 60, 120, 240, 480, 1440 min after drug injection. A PBPK model was developed in rats and extrapolated to human using GastroPlus software. The predictions were assessed by comparing predictions and observations. In the plasma concentration versus time profile of moxifloxcinin rats, $C_{max}$ was $11.151{\mu}g/mL$ at 5 min after the intravenous injection and $t_{1/2}$ was 2.936 h. Plasma concentration and kinetics in human were predicted and compared with observed datas. Moxifloxacin penetrated and accumulated with high concentrations in redmarrow, lung, skin, heart, liver, kidney, spleen, muscle tissues in human with intra-abdominal infection. The predicted tissue to plasma concentration ratios in abdominal viscera were between 1.1 and 2.2. When rat plasma concentrations were known, extrapolation of a PBPK model was a method to predict drug pharmacokinetics and penetration in human. Moxifloxacin has a good penetration into liver, kidney, spleen, as well as other tissues in intra-abdominal infected human. Close monitoring are necessary when using moxifloxacin due to its high concentration distribution. This pathological model extrapolation may provide reference to the PK/PD study of antibacterial agents.

High-efficiency degradation of quinclorac via peroxymonosulfate activated by N-doped CoFe2O4/Fe0@CEDTA hybrid catalyst

Lezhu Su,Lizhou Ou,Yujiao Wen,Yifan Wang,Weilin Zhao,Zhi Zhou,Mei-e Zhong,YONGFA ZHU,Nan Zhou 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.102 No.-

Exploring catalyst materials which are advancing, recyclable and with high catalytic performances toremove persistent organic pollutants such as Quinclorac (QNC) is important. In this work, a novel Ndopedcarbon support CoFe2O4/Fe0 hybrid catalyst (CFO/Fe@C) was in situ formed by a simple coprecipitationand calcination process. Fine intergrowth crystal CoFe2O4 and Fe0 were uniformly dispersedon the N-doped porous carbon that derived from the raw material Ethylene Diamine Tetraacetic Acid(EDTA), which also provided chelating effect to prevent the agglomeration of the metals. Interestingly,the Fe0 could only be formed with the presence of cobalt, possibly due to the increased reduction propertyresulted from the particle refinement. The as-formed Fe0 could not only activate the peroxymonosulfate(PMS) but also reduce the Co3+, resulting in a synergistic impact to remarkably enhance thedegradation performance. Besides, the N-doped porous carbon can also benefit the degradation of pollutantby strengthening the electron transfer. A good degradation efficiency of QNC was obtained in CFO/Fe@C-PMS system and most of the QNC had been degraded to carbon dioxide, water and other smallmolecular organisms. The removal rate remained over 70% after four reuses and the material could beeasily recovered from the solution due to the good magnetic properties. Therefore, the as-preparedCFO/Fe@C catalyst should be an ideal catalyst for the removal of organic pollutants.