Effects of Quenching Methods and Aging Processes on the Crushing Properties and Microstructure of Al–Zn–Mg Alloy Thin-Walled Square Extrusions

Hui Guo,Jin Zhang,Cheng Wang,Yun‑lai Deng 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

In this study, the effects of different (online quenching and offline quenching) quenching methods and aging processes (T6and T73) on the crashworthiness and microstructural evolution of three Al–Zn–Mg alloys (G1–G3) were studied by conductingtensile test and axial compression tests at room temperature, combined with optical metallography, electron back scattereddiffraction, and transmission electron microscopy microstructural observations. The obtained results revealed that thecrushing properties of three different Al–Zn–Mg alloys subjected to different quenching methods and aging processes weresignificantly different. Their crushing energy absorption of are ranked as follows: G1 > G3 > G2. The highest total energyabsorption gap (between T6 and T73) is the G1 alloy, and the lowest one is the G3 alloy. The largest total energy absorptiongap between the two quenching methods is the G3 alloy, and the smallest one is the G1 alloy. The G2 alloy with the largesttotal amount of Zn + Mg has the highest number density of matrix precipitates, the largest precipitate gap (between T6 andT73) and the smallest precipitate gap between the two quenching methods. The G3 alloy with the largest Zn/Mg ratio hasthe smallest number density of matrix precipitates, the minimum precipitation gap (between T6 and T73) and the maximumprecipitation gap between the two quenching methods. The G1 alloy with the lowest Zn/Mg ratio has the smallest size ofgrain boundary precipitates and PFZ width, while their largest values are obtained for the G3 alloy with the maximum Zn/Mg ratio. As a crushing resistant structural material, the crushing properties is improved without reducing the strength. Theratio of Zn/Mg should be controlled within the range of 4.57–6.15, while the total amount of Zn + Mg should be controlledwithin the range of 6.18–7.01.

The Improved Algorithm of Edge Detection Based on Mathematics Morphology

Deng Caixia,Chen Yu,Bi Hui,Han Yao 보안공학연구지원센터 2014 International Journal of Signal Processing, Image Vol.7 No.5

Involvement of Orai1 in tunicamycin-induced endothelial dysfunction

Hui Yang,Yumei Xue,Sujuan Kuang,Mengzhen Zhang,Jinghui Chen,Lin Liu,Zhixin Shan,Qiuxiong Lin,Xiaohong Li,Min Yang,Hui Zhou,Fang Rao,Chunyu Deng 대한약리학회 2019 The Korean Journal of Physiology & Pharmacology Vol.23 No.2

Endoplasmic reticulum (ER) stress is mediated by disturbance of Ca2+ homeostasis. The store-operated calcium (SOC) channel is the primary Ca2+ channel in non-excitable cells, but its participation in agent-induced ER stress is not clear. In this study, the effects of tunicamycin on Ca2+ influx in human umbilical vein endothelial cells (HUVECs) were observed with the fluorescent probe Fluo-4 AM. The effect of tunicamycin on the expression of the unfolded protein response (UPR)-related proteins BiP and CHOP was assayed by western blotting with or without inhibition of Orai1. Tunicamycin induced endothelial dysfunction by activating ER stress. Orai1 expression and the influx of extracellular Ca2+ in HUVECs were both upregulated during ER stress. The SOC channel inhibitor SKF96365 reversed tunicamycin-induced endothelial cell dysfunction by inhibiting ER stress. Regulation of tunicamycin-induced ER stress by Orai1 indicates that modification of Orai1 activity may have therapeutic value for conditions with ER stress-induced endothelial dysfunction.

Involvement of Orai1 in tunicamycin-induced endothelial dysfunction

Yang, Hui,Xue, Yumei,Kuang, Sujuan,Zhang, Mengzhen,Chen, Jinghui,Liu, Lin,Shan, Zhixin,Lin, Qiuxiong,Li, Xiaohong,Yang, Min,Zhou, Hui,Rao, Fang,Deng, Chunyu The Korean Society of Pharmacology 2019 The Korean Journal of Physiology & Pharmacology Vol.23 No.2

Endoplasmic reticulum (ER) stress is mediated by disturbance of $Ca^{2+}$ homeostasis. The store-operated calcium (SOC) channel is the primary $Ca^{2+}$ channel in non-excitable cells, but its participation in agent-induced ER stress is not clear. In this study, the effects of tunicamycin on $Ca^{2+}$ influx in human umbilical vein endothelial cells (HUVECs) were observed with the fluorescent probe Fluo-4 AM. The effect of tunicamycin on the expression of the unfolded protein response (UPR)-related proteins BiP and CHOP was assayed by western blotting with or without inhibition of Orai1. Tunicamycin induced endothelial dysfunction by activating ER stress. Orai1 expression and the influx of extracellular $Ca^{2+}$ in HUVECs were both upregulated during ER stress. The SOC channel inhibitor SKF96365 reversed tunicamycin-induced endothelial cell dysfunction by inhibiting ER stress. Regulation of tunicamycin-induced ER stress by Orai1 indicates that modification of Orai1 activity may have therapeutic value for conditions with ER stress-induced endothelial dysfunction.

Study on the best range of seismotectonic sources in northern China

Zhi-Hui Deng,Myung-Soon Jun(전명순) 대한지질학회 1998 대한지질학회 학술대회 Vol.1998 No.

Throughput Optimization for TCP with an Active Proxy in Long-Delay Satellite Environments

Hui, Wang,Osada, Shigeyuki,Yokohira, Tokumi,Fukushima, Yukinobu,Chaolong, Deng,Okayama, Kiyohiko,Yamai, Nariyoshi 통신위성우주산업연구회 2006 Joint Conference on Satellite Communications Vol.2006 No.-

Although Transmission Control Protocol (TCP) is widely used in the Internet, its performance is poor in networks with long delays. To improve TCP performance in such networks as long-delay satellite environments, the use of a PEP (Performance Enhancing Proxy) has been proposed. The PEP operates on a router that connects a terrestrial link and a satellite link along a TCP connection. When a data packet arrives at the PEP, it forwards the packet to the destination host, transmits the corresponding ACK(premature ACK) to the source host on behalf of the destination host, and stores a copy of the packet in a local buffer (PEP buffer) in case retransmission of the packet is required. As a congestion control method on the PEP, a method that keeps the number of prematurely acknowledged packets in the PEP buffer below a threshold (watermark) value has been proposed. However, an optimization method of the watermark value has not been proposed. In this paper, we propose an adaptive watermark value optimization algorithm that maximizes the average throughput of each connection in response to dynamic establishment and release of connections, under a fairness condition that the average throughputs of connections are equal to each other. Numerical examples using the NS2 simulator for a simple network model show the effectiveness of the proposed algorithm.

Effect of Deep Cryogenic Treatment on Machinability and Wear Mechanism of TiAlN Coated Tools during Dry Turning

Hui-Bo He,Wen-Qiang Han,Hua-Ying Li,Dong-Yang Li,Jun Yang,Tao Gu,Tao Deng 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

TiAlN coatings were deposited on the YT15 tungsten carbide inserts by magnetron sputtering technique. The TiAlN coated tools weredeep cryogenic treatment (DCT) at -196oC for 30 h. The dry turning tests of 40Cr steel were carried out to evaluate performancesof uncoated, no cryogenically treated (NCT) and DCT coated tools on the CA6140A lathe. The effect of the three kinds of tools oncutting forces, cutting temperature, surface qualities and tool wear had been investigated to assess the performance of DCT coatedtools. Results of the investigation showed that the cutting forces and cutting temperature obtained by DCT coated tools weresignificantly decreased in comparison with the uncoated and NCT coated tools, especially at higher cutting speeds. Flank wear ofthe DCT coated inserts was less than that of the NCT coated inserts under the same cutting conditions. The DCT coated insertsproduced a good surface finish and yield a tool life of about 65 min. The wear mechanisms of the DCT coated carbide tools are mainlyabrasive and adhesive wear, accompanied with diffusion and oxidation wear.

Two Evaluation Budgets for the Measurement Uncertainty of Glucose in Clinical Chemistry

Hui Chen,Ling Zhang,Xiaoyun Bi,Xiaoling Deng 대한진단검사의학회 2011 Annals of Laboratory Medicine Vol.31 No.3

Background: Measurement uncertainty characterizes the dispersion of the quantity values attributed to a measurand. Although this concept was introduced to medical laboratories some years ago, not all medical researchers are familiar with it. Therefore, the evaluation and expression of measurement uncertainty must be highlighted using a practical example. Methods: In accordance with the procedure for evaluating and expressing uncertainty, provided by the Joint Committee for Guides in Metrology (JCGM), we used plasma glucose (Glu) as an example and defined it as the measurand. We then analyzed the main sources of uncertainty, evaluated each component of uncertainty, and calculated the combined uncertainty and expanded uncertainty with 2 budgets for single measurements and continuous monitoring, respectively. Results: During the measurement of Glu, the main sources of uncertainty included imprecision, within-subject biological variance (BVw), calibrator uncertainty, and systematic bias. We evaluated the uncertainty of each component to be 1.26%, 1.91%, 5.70%, 0.42%, and -2.87% for within-run imprecision, between-day imprecision, BVw, calibrator uncertainty, and systematic bias, respectively. For a single specimen, the expanded uncertainty was 7.38% or 6.1±0.45 mmol/L (κ=2); in continuous monitoring of Glu, the expanded uncertainty was 13.58% or 6.1±0.83 mmol/L (κ=2). Conclusions: We have demonstrated the overall procedure for evaluating and reporting uncertainty with 2 different budgets. The uncertainty is not only related to the medical laboratory in which the measurement is undertaken, but is also associated with the calibrator uncertainty and the biological variation of the subject. Therefore, it is helpful in explaining the accuracy of test results. Background: Measurement uncertainty characterizes the dispersion of the quantity values attributed to a measurand. Although this concept was introduced to medical laboratories some years ago, not all medical researchers are familiar with it. Therefore, the evaluation and expression of measurement uncertainty must be highlighted using a practical example. Methods: In accordance with the procedure for evaluating and expressing uncertainty, provided by the Joint Committee for Guides in Metrology (JCGM), we used plasma glucose (Glu) as an example and defined it as the measurand. We then analyzed the main sources of uncertainty, evaluated each component of uncertainty, and calculated the combined uncertainty and expanded uncertainty with 2 budgets for single measurements and continuous monitoring, respectively. Results: During the measurement of Glu, the main sources of uncertainty included imprecision, within-subject biological variance (BVw), calibrator uncertainty, and systematic bias. We evaluated the uncertainty of each component to be 1.26%, 1.91%, 5.70%, 0.42%, and -2.87% for within-run imprecision, between-day imprecision, BVw, calibrator uncertainty, and systematic bias, respectively. For a single specimen, the expanded uncertainty was 7.38% or 6.1±0.45 mmol/L (κ=2); in continuous monitoring of Glu, the expanded uncertainty was 13.58% or 6.1±0.83 mmol/L (κ=2). Conclusions: We have demonstrated the overall procedure for evaluating and reporting uncertainty with 2 different budgets. The uncertainty is not only related to the medical laboratory in which the measurement is undertaken, but is also associated with the calibrator uncertainty and the biological variation of the subject. Therefore, it is helpful in explaining the accuracy of test results.

Dynamic Spectrum Sharing for Hybrid Access in OFDMA-Based Cognitive Femtocell Networks

Deng, Qingyong,Li, Zhetao,Chen, Jiabei,Zeng, Fanzi,Wang, Hui-Ming,Zhou, Liang,Choi, Young-June IEEE 2018 IEEE Transactions on Vehicular Technology VT Vol.67 No.11

<P>Cognitive femtocell has emerged as one of the promising ways to solve the indoor coverage and spectrum shortage problems in cellular networks. However, it is a challenge to motivate both macro base station ( <TEX>$\text{MBS}$</TEX>) and femtocell access points ( <TEX>$\text{FAPs}$</TEX>) to adopt this hybrid access policy. In this paper, we propose a systematic dynamic spectrum sharing framework for hybrid access in orthogonal frequency-division multiple-access-based cognitive macro-femtocell networks. In this framework, the <TEX>$\text{MBS}$</TEX> offloads some macro user equipments ( <TEX>$\text{MUEs}$</TEX>) to <TEX>$\text{FAP}$</TEX> to improve the transmission performance and save energy. In return, the MBS leases a portion of its spectrum to <TEX>$\text{FAP}$</TEX>. Then, the <TEX>$\text{FAP}$</TEX> can use a part of spectrum for its own transmission and use another part to serve <TEX>$\text{MUEs}$</TEX>. We design an auction-based approach where each <TEX>$\text{FAP}$</TEX> receives additional <TEX>$\text{MUE}$</TEX> as bidders, while MBS acts as auctioneer. We formulate the dynamic resource sharing as a sum utility maximization problem. Numerical results demonstrate that both the macro and femtocell could get benefit from our framework.</P>

Asynchronous H∞ Control for Positive Discrete-time Markovian Jump Systems

Hui Shang,Wenhai Qi,Guang-Deng Zong 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.2

This paper deals with the asynchronous H∞ control for discrete-time positive Markovian jump systems (PMJSs). In previous results about PMJSs, asynchronous behaviors are always overlooked and the designed controller is based on the synchronization between the system modes and controller modes. Sufficient conditions for stochastic stability are proposed by the use of Lyapunov-Krasovskii functional. The asynchronous controller is designed to ensure the closed-loop system stochastically stable with a prescribed H∞ performance index. All the conditions are given in linear matrix inequality framework. Finally, a pest’s age-structured population dynamic model is illustrated to show the validity of the present design.