Browsing by Author "Zhang, Yu"

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A Method of Driving Characteristics Recognition on Vehicle Operation Sequence
(2019-01-01)
Zhang, Yu
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Shen, Bo
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Kao, Yi-Chih
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Chou, Hsin-Hung
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Driving behavior has been proved to have a great influence on road safety. Recognizing driving characteristic is an essential part of reducing traffic fatalities and developing intelligent traffic system. In this paper, we propose a method of driving characteristics recognition through mining vehicle operation data such as GPS, velocity and direction collected by the On-Board Diagnostic (OBD) port of vehicles. Based on the feature extracted from the vehicle operation sequence, we employ K-means algorithm to cluster and recognize different driving characteristics after reasonable normalization and dimensionality reduction of the features. Analysis and experimental results indicate that the proposed method has good application significance on mining effective information in vehicle operation data sequence.
AMP-activated Protein Kinase Phosphorylation of Angiotensin-Converting Enzyme 2 in Endothelium Mitigates Pulmonary Hypertension
(2018-08-15)
Zhang, Jiao
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Dong, Jianjie
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Martin, Marcy
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He, Ming
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Gongol, Brendan
Rationale: Endothelial dysfunction plays an integral role in pulmonary hypertension (PH). AMPK (AMP-activated protein kinase) and ACE2 (angiotensin-converting enzyme 2) are crucial in endothelial homeostasis. The mechanism by which AMPK regulates ACE2 in the pulmonary endothelium and its protective role in PH remain elusive. Objectives: We investigated the role of AMPK phosphorylation of ACE2 Ser680 in ACE2 stability and deciphered the functional consequences of this post-translational modification of ACE2 in endothelial homeostasis and PH. Methods: Bioinformatics prediction, kinase assay, and antibody against phospho-ACE2 Ser680 (p-ACE2 S680) were used to investigate AMPK phosphorylation of ACE2 Ser680 in endothelial cells. Using CRISPR-Cas9 genomic editing, we created gain-of-function ACE2 S680D knock-in and loss-of-function ACE2 knockout (ACE22/2) mouse lines to address the involvement of p-ACE2 S680 and ACE2 in PH. The AMPK-p-ACE2 S680 axis was also validated in lung tissue from humans with idiopathic pulmonary arterial hypertension. Measurements and Main Results: Phosphorylation of ACE2 by AMPK enhanced the stability of ACE2, which increased Ang (angiotensin) 1-7 and endothelial nitric oxide synthase-derived NO bioavailability. ACE2 S680D knock-in mice were resistant to PH as compared with wild-type littermates. In contrast, ACE2-knockout mice exacerbated PH, a similar phenotype found in mice with endothelial cell-specific deletion of AMPK alpha 2. Consistently, the concentrations of phosphorylated AMPK, p-ACE2 S680, and ACE2 were decreased in human lungs with idiopathic pulmonary arterial hypertension. Conclusions: Impaired phosphorylation of ACE2 Ser680 by AMPK in pulmonary endothelium leads to a labile ACE2 and hence is associated with the pathogenesis of PH. Thus, AMPK regulation of the vasoprotective ACE2 is a potential target for PH treatment.
Bacterial Concentration Detection using a PCB-based Contactless Conductivity Sensor
(2019-01-01)
Zhang, Xiao-Yan
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Li, Zhe-Yu
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Zhang, Yu
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Zang, Xiao-Qian
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Ueno, Kosei
Capacitively coupled contactless conductivity detection ((CD)-D-4) is an improved approach to avoid the problems of labor-intensive, time-consuming and insufficient accuracy of plate count as well as the high-cost apparatus of flow cytometry (FCM) in bacterial counting. This article describes a novel electrode-integrated printed-circuit-board (PCB)-based (CD)-D-4 device, which supports the simple and safe exchange of capillaries and improves the sensitivity and repeatability of the contactless detection. Furthermore, no syringe pump is needed in the detection, it reduces the system size, and, more importantly, avoids the effect on the bacteria due to high pressure. The recovered bacteria after (CD)-D-4 detection at excitation of 25 Vpp and 60-120 kHz were analyzed by flow cytometry, and a survival rate higher than 96% was given. It was verified that (CD)-D-4 detection did not influence the bacterial viability. Moreover, bacteria concentrations from 10(6) cells/mL to 10(8) cells/mL were measured in a linear range, and relative standard deviation (RSD) is below 0.2%. In addition, the effects on bacteria and (CD)-D-4 from background solutions were discussed. In contrast to common methods used in most laboratories, this method may provide a simple solution to in situ detection of bacterial cultures.
Effect of Controlled Growth Dynamics on the Microstructure of Nonpolar a-Plane GaN Revealed by X-ray Diffraction
(2009-07-01)
Sun, Qian
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Ko, Tsung-Shine
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Yerino, Christopher D.
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Zhang, Yu
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Lee, In-Hwan
This paper reports the effect of controlled growth dynamics, as monitored by in situ optical reflectance, on the microstructure of nonpolar a-plane GaN films grown on r-plane sapphire. The mosaic microstructure of a-plane GaN and its anisotropy are evaluated by X-ray rocking curve (XRC) measurements. By inserting a pronounced islanding stage followed by an enhanced lateral growth, pit-free a-plane GaN has been achieved showing an XRC linewidth of similar to 0.18 and similar to 0.3 degrees for on- and off-axes planes, respectively, with only minor anisotropy. The density of basal-plane stacking faults is reduced by similar to 70% as determined by a modified Williamson-Hall X-ray analysis. (C) 2009 The Japan Society of Applied Physics DOI: 10.1143/JJAP.48.071002
Nonfullerene Polymer Solar Cell with Large Active Area of 216 cm(2) and High Power Conversion Efficiency of 7.7%
(2019-08-01)
Huang, Kuan-Min
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Lin, Chih-Ming
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Chen, Szu-Han
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Li, Cheng-Sian
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Hu, Chen-Hsuan
A polymer solar cell involving a nonfullerene acceptor is made by blade coating. In the ternary bulk-heterojunction layer, the donor is poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene))-co-(1,3-di(5-thiophene-2-yl)- 5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione)] (PBDB-T) and the acceptor is a mixture of 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene) (ITIC) and [6,6]-phenyl C-71-butyric acid methyl ester (PC71BM). The device structure is an indium tin oxide (ITO)-coated glass substrate/PEDOT:PSS/ternary active layer/interfacial layer/Al. For a small active area of 0.04 cm(2), the best power conversion efficiency is 9.8% with the LiF interfacial layer. For a large active area of 216 cm(2), the best efficiency is 7.7% with the ZrOx interfacial layer. After annealing at 85 degrees C for 30 days, the large-area device keeps 75% of the initial efficiency. The efficiency of 4.9% is achieved for a large-area semi-transparent device.