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.

호이스트용 SRM의 구동시스템의 특성해석

이진국,이동희,안진우 경성대학교 공학기술연구소 2005 공학기술연구지 Vol.12 No.-

This paper presents a development of Switched Reluctance Motor (SRM) drive system for a hoist application. In the hoist system, smoothing start-up and braking are very important for a protection of goods. In order to improved a start-up and a stop performance of hoist system, the smoothing operation sequence of SRM using direct instantaneous torque control is proposed. The proposed Direct Instantaneous Torque Control (DITC) the instantaneous torque of SRM according to the switching sequence and hysteric band. In order to compare the reference and actual torque of SRM, pre-measured flux and torque look-up table are regulate used. The proposed SRM Drive system is verified by the simulation result.

4-레벨 인버터를 이용한 고속 SRM 구동시스템

이동희,이진국,안진우 경성대학교 공학기술연구소 2005 공학기술연구지 Vol.12 No.-

This paper proposes high speed SRM drive system for blower with a novel 4-level inverter and precise excitation position generator. In order to get a fast build-up and a demagnetization of excitation current, 4-level inverter system is proposed. The proposed 4-level inverter has additional charge capacitor, power switch and diode in the conventional asymmetric converter. The charged high voltage is supplied to the phase winding for fast current build- up, and demagnetization current is charged to additional capacitor of 4-level inverter. In addition, a precise excitation position generator can reduce turn-on and turn-off angle error according to sampling period of digital control system. The proposed high speed SRM drive system is verified by computer simulations and experimental results.

Brand Personality Recognition from Analytic Hierarchy Process Perspective

Guo Rui Jin 원광대학교 한중관계연구원 2020 韓中關係硏究 Vol.6 No.2

오늘날 세계경제의 친밀화가 점점 심화되고 있다. 생산과정의 분화와 판매지점의 국제화는 세계무역의 형세를 바꾸어 이른바 글로벌화 되고 있다. 브랜드 경제는 중요 한 무형적 가치를 가진 것으로, 이는 국가경쟁력을 제고하고, 글로벌 경제활동에서 유 리한 고지를 선점하게 하는 중요한 역할을 한다. 본 연구에서는 브랜드 아이덴티티의 관점에서 경제통합추세에 따른 브랜드 경제의 국가전략과 기업생존에 미치는 중요한 영향이 무엇인지 검토하고, 이른바 브랜드 경제 에 있어 브랜드 아이덴티티와 소비자 구매의사 간의 긴밀한 연관성을 탐구함으로써 브랜드 관리 경제에 중요한 자료로 제공될 것이다. 이를 위해 차원분석법에 기초한 서열화 알고리즘을 통해 브랜드 관리자가 특화된 브랜드의 특징을 맞춤화하고, 아이덴 티티를 계량화하여 평가함으로써 궁극적으로 브랜드의 아이덴티티를 실현할 수 있도 록 한다. 또한, 이러한 방법론의 타당성과 적용상의 논증을 위해 두 가지 전형 사례를 도입하여 검토함으로써 브랜드 아이덴티티의 개발과 관리라는 관점에서 독특한 브랜 드를 구축하기 위한 전략을 제시하였다. In the current integrated global economy, the unbundling of the production process and the distribution of production stages in multinational locations result in trade patterns being shifted and reshaped. And as one of the intangible but powerful forces, the economic importance of the brand is playing a significant role to form a nation’s core competitiveness and advantageous position in global economic activity. However, the elaboration of previous studies of brand value mostly focus on the theoretical level, and as an important attribute of the brand, the exploration of brand personality focuses on ambiguous expositional judgment, while few have concerned on the recognition methods of dimensional efficiency as an accurate quantification, which made the vital challenges of brand operators regarding the key brand personality dimension recognition and quantification to be blank and of limited help for brand operators in practical operation. In this paper, we propose an analytical hierarchy process (AHP) based ranking algorithm to recognize the key brand personality and figure out the level of importance with a clear ranking on dimensions, which fills the academic gap on brand personality quantification. To explain the feasibility and universal applicability of this method, the importance priority of brand characteristics is carried out by using the analytic hierarchy process in two different scenarios.

Isolation of pollutant-responding genes form the seaweed Porphyra yezoensis tiss

Jin, Long-Guo 부경대학교 수산과학연구소 2003 硏究業績集 Vol.27 No.-

ON THE (n, d)^th f-IDEALS

GUO, JIN,WU, TONGSUO Korean Mathematical Society 2015 대한수학회지 Vol.52 No.4

For a field K, a square-free monomial ideal I of K[$x_1$, . . ., $x_n$] is called an f-ideal, if both its facet complex and Stanley-Reisner complex have the same f-vector. Furthermore, for an f-ideal I, if all monomials in the minimal generating set G(I) have the same degree d, then I is called an $(n, d)^{th}$ f-ideal. In this paper, we prove the existence of $(n, d)^{th}$ f-ideal for $d{\geq}2$ and $n{\geq}d+2$, and we also give some algorithms to construct $(n, d)^{th}$ f-ideals.

Weibull parameter estimation and reliability analysis with small samples based on successive approximation method

Jin Guo,Xiangwei Kong,Ningxiang Wu,Liyang Xie 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.11

Only few failure data can be collected because of increasing costs and reliability. Therefore, improving the estimation accuracy of Weibull distribution with small samples has become an urgent problem. In this study, a method for estimating the Weibull parameter and analyzing reliability is proposed based on the successive approximation method. In this method, the effect of sample size on the location parameter is considered to establish an iterative model of the location parameter. The iterative equations of scale and shape parameters are constructed based on the location parameter and failure data. Then, an extensive MonteCarlo simulation study is conducted to compare the performance of the proposed method with the existing methods. Simulation results show that the proposed method is superior for estimating Weibull parameters and reliability in terms of precision, robustness, and efficiency. Finally, two real examples are analyzed to illustrate the application of the proposed method.

Purification and Characterization of an Extracellular Protease from Bacillus pumilus CN8

Jin, Yong-Guo,Li, Hao-Li,Mal, Mei-Hu,Wang, Jun,Kim, Ha-Na,Oh, Deog-Hwan The Korean Society of Food Hygiene and Safety 2011 한국식품위생안전성학회지 Vol.26 No.1

The protease produced by a Bacillus pumilus CN8 strain was purified by DEAE-Cellulose-52 ion exchange. It has a molecular weight of approximately 96,920 Dalton. In the present study, this protease showed strong activity over a broad range of pH (6.5-9.5) and temperature from $40^{\circ}C$ to $60^{\circ}C$, and the protease performed the maximal activity at pH 7.3 at $42^{\circ}C$. The effect of metal ions on protease activity showed that $K^+$ could slightly increase the protease activity, and other ions such as $Zn^{2+}$, $Fe^{2+}$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$ had no significant activation or inhibition to the protease (P> 0.05), and the more important is that $Cu^{2+}$, $Mn^{2+}$, $Sn^{2+}$, $Cd^{2+}$ had a strong inhibitory effect on the protease activity.

Production of 2,3-Butanediol by Pdc-deficient Saccharomyces cerevisiae Expressing of Lactococcus lactis NADH Oxidase

Jin-Woo KIM,Seung-Oh SEO,Guo-Chang ZHANG,Yong-Su JIN,Jin-Ho SEO 한국생물공학회 2015 한국생물공학회 학술대회 Vol.2015 No.10

Effects of Stellate Ganglion Block on the Peri-operative Vasomotor Cytokine Content and Intrapulmonary Shunt in Patients with Esophagus Cancer

Guo, Wei,Jin, Xiao-Ju,Yu, Jun,Liu, Yang,Zhang, Jian-Ping,Yang, Da-Wei,Zhang, Lei,Guo, Jiang-Rong Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.21

Objective: To investigate the effects of stellate ganglion block (SGB) on the peri-operative vasomotor cytokine content and intrapulmonary shunt in patients with esophagus cancer who underwent thoracotomy. Materials and Methods: Forty patients undergoing elective resection of esophageal cancer patients who had I~II American Society of Anesthesiologist (ASA) were randomly divided into total intravenous anesthesia group (group N, n=20) and total intravenous anesthesia combined with SGB group (group S, n=20, 0.12 mL/kg 1% lidocaine was used for SGB 10 min before induction). Heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), mean pulmonary arterial pressure (MPAP) and continuous cardiac output (CCO) were continuously monitored. The blood from internal jugular vein was drawn respectively before induction ($T_0$), and 30 min ($T_1$), 60 min ($T_2$) and 120 min ($T_3$) after one-lung ventilation (OLV), and 30 min (T4) after two-lung ventilation. The contents of plasma endothelin (ET), nitric oxide (NO) and calcitonin gene-related peptide (CGRP) were detected with enzyme linked immunosorbent assay (ELISA). Meanwhile, arterial and mixed venous blood samples were collected for determination of blood gas and calculation of intrapulmonary shunt fraction (Qs/Qt). Results: During OLV, ET contents were increased significantly in two groups (P<0.05), and no significant difference was presented (P>0.05). NO content in group S was obviously higher than in group N at T3 (P<0.05), whereas CGRP content in group N was markedly lower than in group S at each time point (P<0.05). Qs/Qt was significantly increased in both groups after OLV, but there was no statistical significant regarding the Qs/Qt at each time point between two groups. Conclusions: Total intravenous anesthesia combined with SGB is conducive to regulation of perioperative vasomotor cytokines in thoracotomy, and has little effect on intrapulmonary shunt at the time of OLV.