Performance enhancements of Pb(Mg1/3Nb2/3)O3-xPbTiO3 single crystal/epoxy 1–3 composite by alternating current polarization

Hang Hai,Jiang Xianyao,Lin Di,Wang Feifei,Wang Xian,Luo Haosu 한국물리학회 2023 Current Applied Physics Vol.47 No.-

Pb(Mg1/3Nb2/3)O3-xPbTiO3 single crystal/epoxy 1–3 piezoelectric composite was designed to decrease acoustic impedance and to improve the electromechanical property, which was vital to the ultrasound transducers. The piezo-/dielectric properties of the PMNT/epoxy 1–3 composites prepared by the different poling methods were measured. It was found that piezoelectric coefficient d33, dielectric constant εT33/ε0, and electromechanical factor kt of composites exhibited the significant increases of 16.41%, 6.89%, and 1.97% under optimized alternating current polarization (ACP), compared with those of the samples using direct current polarization (DCP). The domain patterns suggested that the remarkable regular striped domain and high domain wall density of the ACP sample could result in performance enhancements. The ACP composite-based transducer’s bandwidth (BW) and relative sensitivity (RS) were improved by 6.27% and 1.93 dB. These results indicated that the ACP effectively enhances the piezoelectric composite’s performances, and BW and RS of the transducer based on ACP piezoelectric materials are improved simultaneously.

Mercury Resistance and Removal Mechanisms of Pseudomonas sp. Isolated Mercury-contaminated Site in Taiwan

Luo, Kai-Hong,Chen, Ssu-Ching,Liao, Hung-Yu Korean Society of Soil and Groundwater Environment 2016 지하수토양환경 Vol.21 No.5

A new strain of Pseudomonas sp. was isolated from mercury (Hg)-contaminated sites in Taiwan. This bacterium removed more than 80% of Hg present in the culture medium at 12 h incubation and was chosen for further analysis of the molecular mechanisms of Hg tolerance/removal abilities in this Pseudomonas sp. We used RNA-seq, one of the next-generation sequencing methods, to investigate the transcriptomic responses of the Pseudomonas sp. exposed to 60 mg/L of Hg²⁺. We de novo assembled 4,963 contigs, of which 10,533 up-regulated genes and 5,451 down-regulated genes were found to be regulated by Hg. The 40 genes most altered in expression levels were associated with tolerance to Hg stress and metabolism. Functional analysis showed that some Hg-tolerant genes were related to the mer operon, sulfate uptake and assimilation, the enzymatic antioxidant system, the HSP gene family, chaperones, and metal transporters. The transcriptome were analyzed further with Gene Ontology (GO) and Cluster of Orthologous Groups (COGs) of proteins and showed diverse biological functions and metabolic pathways under Hg stress.

A generalized algorithm for the study of bilinear vibrations of cracked structures

Luo, Tzuo-Liang,Wu, James Shih-Shyn,Hung, Jui-Pin Techno-Press 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.23 No.1

Structural cracks may cause variations in structural stiffness and thus produce bilinear vibrations to structures. This study examines the dynamic behavior of structures with breathing cracks. A generalized algorithm based on the finite element method and bilinear theory was developed to study the influence of a breathing crack on the vibration characteristic. All the formulae derived in the time domain were applied to estimate the period of the overall bilinear motion cycle, and the contact effect was considered in the calculations by introducing the penetration of the crack surface. Changes in the dynamic characteristics of cracked structures are investigated by assessing the variation of natural frequencies under different crack status in either the open or closed modes. Results in estimation with vibrational behavior variation are significant compared with the experimental results available in the literature as well as other numerical calculations.

ROBUST CONTROL FOR FOUR-WHEEL-INDEPENDENT-STEERING ELECTRIC VEHICLE WITH STEER-BY-WIRE SYSTEM

Peng Hang,Xinbo Chen,Shude Fang,Fengmei Luo 한국자동차공학회 2017 International journal of automotive technology Vol.18 No.5

A four-wheel-independent-steering (4WIS) electric vehicle (EV) with steer-by-wire (SBW) system is proposed in this paper. The fast terminal sliding mode controller (FTSMC) is designed for the SBW system to suppress external disturbances. Taking unstructured and structured uncertainties into consideration, a robust controller is designed for the 4WIS EV utilizing μ synthesis approach and the controller order reduction is implemented based on Hankel-Norm approximation. Since sideslip angle is the feedback signal of robust controller and it is hard to measure, the extended Kalman filter (EKF) is employed to estimate sideslip angle. To evaluate the vehicle performance with the designed control system, step and sinusoidal steering maneuvers are simulated and analyzed. Simulation results show that the designed control system have good tracking ability, strong robust stability and good robust performance to improve vehicle stability and handing performance.

Visible light induced g-C3N4/TiO2/Ti3C2 ternary Z-scheme heterojunction photocatalyst for efficient degradation

Menghao Luo,Hange Feng,Yuechuan Hu,Keke Chen,Zibo Dong,Shaolin Xue 대한금속·재료학회 2023 ELECTRONIC MATERIALS LETTERS Vol.19 No.1

Photocatalytic degradation has received considerable emphasis since it shows signifi cant possibilities in environmentalpollution. In this work, ternary Z-scheme heterojunction g-C 3 N 4 /TiO 2 /Ti 3 C 2 photocatalysts are designed and fabricated. The Z-scheme heterojunctions formed on the surfaces of g-C 3 N 4 and TiO 2 dramatically modify the photocatalyticperformances of the compound under illumination. Meanwhile, in this process, multilayer Ti 3 C 2 , as the transport mediumof Z-scheme heterojunction, is tightly bonded to TiO 2 generated by hydrothermal oxidation and g-C 3 N 4 with large specifi csurface area, which eff ectively facilitates the space charge separation and depresses the charge recombination. When theaddition amount of TiO 2 /Ti 3 C 2 is 80 mg and calcined at 450 ℃ for 4 h, g-C 3 N 4 /TiO 2 /Ti 3 C 2 has the greatest photocatalyticperformance, and the kinetic constant for degradation methyl orange (MO) was about 3.62 times that of g-C 3 N 4 and 14.55times that of Ti 3 C 2 , respectively. This work illustrates that g-C 3 N 4 /TiO 2 /Ti 3 C 2 has outstanding potential and off ers novelinsights for designing and synthesizing new ternary heterojunction materials.

Screening of Antagonistic Bacillus against Brown Rot in Dendrocalamus latiflorus and Preparation of Applying Bacterial Suspension

Fengying Luo,Hang Chen,Wenjian Wei,Han Liu,Youzhong Chen,Shujiang Li 한국식물병리학회 2024 Plant Pathology Journal Vol.40 No.1

The aim of this study was to isolate biocontrol bacteria that could antagonize brown rot of <i>Dendrocalamus latiflorus</i>, optimize the culture conditions, and develop an effective biocontrol preparation for brown rot of <i>D. latiflorus</i>. This study isolated a bacterium with an antagonistic effect on bamboo brown rot from healthy <i>D. latiflorus</i> rhizosphere soil. Morphology, molecular biology, and physiological biochemistry methods identified it as <i>Bacillus siamensis</i>. The following culturing media and conditions improved the inhibition effect of <i>B. siamensis</i>: the best culturing media were 2% sucrose, 1.5% yeast extract, and 0.7% potassium chloride; the optimal culturing time, temperature, pH, and inoculation amount were 48 h, 30℃, 6, and 20%. The optimum formula of the applying bacterial suspension was 14% sodium dodecyl benzene sulfonate emulsifier, 4% Na₂HPO₄·2H₂O, 0.3% hydroxypropyl methylcellulose thickener, and 20% <i>B. siamensis</i>. The pot experiment results showed the control effect of applying bacterial suspension, diluted 1,000 times is still better than that of 24% fenbuconazole suspension. The applying bacterial suspension enables reliable control of brown rot in <i>D. latiflorus</i>.

LPV/H ∞ CONTROLLER DESIGN FOR PATH TRACKING OF AUTONOMOUS GROUND VEHICLES THROUGH FOUR-WHEEL STEERING AND DIRECT YAW-MOMENT CONTROL

Peng Hang,Xinbo Chen,Fengmei Luo 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.4

This paper focuses on the path-tracking controller design for autonomous ground vehicles (AGVs) using fourwheel steering (4WS) and direct yaw-moment control (DYC) systems. In order to deal with the parametric uncertainties, a linear parameter-varying (LPV) H∞ controller is designed as the high-level controller to generate the front and rear wheel steering angles and external yaw moment based on linear matrix inequality (LMI) approach. The lower-level controller is designed for torque allocation between the left and right side wheels to yield the desired total longitudinal force and external yaw moment utilizing weighted least square (WLS) allocation algorithm. To test the performance of the proposed pathtracking controller, numerical simulations are carried out based on a high-fidelity and full-vehicle model constructed in CarSim. Simulation results show that the LPV/H∞ controller has better path-tracking performance than the fixed gain H∞ controller. To show the superiority of 4WS+DYC control system, the contrast simulation is performed based on LPV/H∞ controller. Simulation results indicate that 4WS+DYC control system has better path-tracking performance and handling stability than active front steering (AFS), AFS+DYC and 4WS control systems.

Experimental and numerical investigation on post-earthquake fire behaviour of the circular concrete-filled steel tube columns

Yu-Hang Wang,Qi Tang,Mei-Ni Su,Ji-Ke Tan,Wei-Yong Wang,Yong-Sen Lan,Xiao-Wei Deng,Yong-Tao Bai,Wei Luo,Xiao-Hua Li,Jiu-Lin Bai 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.38 No.1

Post-earthquake fire is a common disaster which causes serious safety issues to infrastructures. This study aims to investigate the residual loading capacities of circular concrete-filled steel tube (CFST) columns under post-earthquake fire experimentally and numerically. The experimental programme contains two loading steps - pre-damage cyclic loading at room temperature and transient state tests with constant compression loads. Three finite element models are developed and validated against the test results. Upon validation, a total of 48 numerical results were generated in the parametric study to investigate the effects of thickness and strengths of steel tube, axial compression ratio and damage degree on the fire resistance of circular CFST columns. Based on the analysis on experimental and numerical results, the loading mechanism of circular CFST columns is discussed. A design method is proposed for the prediction of fire resistance time under different seismic pre-damage and compression loads. The predictions by the new method is compared with the newly generated experimental and numerical results and is found to be accurate and consistent with the mean value close to the unity and a coefficient of variation around 1%.

Photo-Electrical Properties of Trilayer MoSe2 Nanoflakes

Yang Hang,Qi Li,Wei Luo,Yanlan He,Xueao Zhang,GANG PENG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.7

The photo-electrical properties of trilayer MoSe2 nanoflakes, fabricated by mechanical exfoliation, were systematically studied in this paper. The trilayer MoSe2 nanoflakes are n-type and possess a high gate modulation (On/Off ratio is larger than 10 5) and a relatively high carrier mobility (1.79 cm2 V-1 s-1). The field effect transistor (FET) device of MoSe2 shows sensitive photo response, high photoresponsivity (Rλ = 26.2 mA/W), quick response time (t < 20 ms), high external quantum efficiency (η = 5.1%) and high detection rate (D = 2.7 x 10 9 W-1) for red and near-infrared wavelength. These results showed that the device based on few-layer MoSe2 nanoflakes exhibited good photo-electrical properties, which might open a new way to develop few-layer MoSe2-based material in the application of FETs and optoelectronics.

Serum Carbohydrate Antigen 19-9 as an Indicator of Liver Metastasis in Colorectal Carcinoma Cases

Dong, Hang,Tang, Jie,Li, Long-Hao,Ge, Jun,Chen, Xin,Ding, Jing,Men, Hai-Tao,Luo, Wu-Xia,Du, Yang,Li, Cong,Zhao, Feng,Chen, Ye,Cheng, Ke,Liu, Ji-Yan Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.2

Purpose: The liver is the organ to which colorectal carcinomas (CRCs) most commonly metastasize, and surgical resection has been established as the most effective and potentially curative treatment for CRC with liver metastasis (LM). Therefore, surveillance of LM is vital for improvement of prognosis of CRC patients. In this study, we aimed to explore the potential value of carbohydrate antigen 19-9 (CA 19-9), carcinoembryonic antigen (CEA), and marker enzymes in indicating LM with CRC. Methods: Three groups of eligible patients with metastatic cancers were retrospectively included: CRC patients with LM (CRC-LM) or without LM (CRC-NLM), and non-CRC patients with LM (NCRC-LM). All metastatic lesions were identified by CT or MRI. Data on characteristics of the patients, the primary site, the locations of metastasis, CA 19-9, CEA, and biochemical parameters were collected for analysis. Results: A total of 493 patients were retrospectively included. More alcohol consumption was found in CRC-LM than CRC-NLM. Some biochemical enzymes were found to be significantly higher in groups with LM than without (CRC-LM or NCRC-LM v.s CRC-NLM). Both CEA and CA 19-9 were much higher in CRC-LM than CRC-NLM or NCRC-LM. For CRC patients, CA 19-9, ${\gamma}$-glutamyl transpeptidase, CEA and alcohol consumption were identified as independent factors associated with LM. Conclusion: Our analysis suggested the CA 19-9 might be a potential valuable indicator for LM of CRC in the clinic.