Effects of Cooling Rate on the Microstructure and Tensile Properties of Wire-Arc Additive Manufactured Ti–6Al–4V Alloy

Hui‑Jun Yi,Jin‑Woo Kim,Young‑Lak Kim,Sangyong Shin 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.8

Wire-arc additive manufacturing has emerged as a technology that could replace the conventional manufacturing processof titanium alloys. However, it produces a coarse β grain, which can accumulate via several deposited materials, resulting isstrong texture and anisotropy. To investigate potential solutions, the effects of the cooling rate on the resulting microstructureand tensile properties were studied. The cooling rate of the deposited materials was adjusted by interpass temperaturecontrol. Under rapid cooling, fine α + α′ grain with a low aspect ratio were observed and tensile and hardness propertieswere also improved.

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.

Four new compounds from the bulbs of Lycoris aurea with neuroprotective effects against CoCl2 and H2O2-induced SH-SY5Y cell injuries

An Jin,Xuelian Xiang,Yun-Yun Zhu,Heng-Yi Yu,Hui-Fang Pi,Peng Zhang,Han-Li Ruan 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.3

Three new alkaloids, 2a-hydroxy-6-O-n-butyloduline,O-n-butyllycorenine, (-)-N-(chloromethyl)lycoramine(1–3), and a new phenolic compound, ((7S)-7-(4-hydroxyphenyl)-7-hydroxypropyl)-20-methylbenzene-30,60-diol (14), along with ten known alkaloids (4–13), wereisolated from the bulbs of Lycoris aurea collected fromHuaihua County of Hunan Province, China. Their structureswere elucidated by spectroscopic methods includingHRESIMS, UV, IR, and NMR. All the isolated compoundswere tested for their neuroprotective effects against CoCl2and H2O2-induced SH-SY5Y cell death. Compounds 1–7and 10 exhibited significant neuroprotective effects againstCoCl2-induced SH-SY5Y cell injury, while compounds1–5, 7, 10 and 12 showed obvious neuroprotective effectsagainst H2O2-induced SH-SY5Y cell death.

Sol-Gel법을 이용한 Silica Membrane의 제조 공정에 관한 조사 연구

이진휘 건국대학교 1991 論文集 Vol.32 No.1

The general informations of sol-gel process are reviewed. Successful applications are dependent on sufficient scientific understanding of the various stages and factors of the process. A number of factors governing the development of the structure and microstructure during gelation and subsequent drying and firing conditions are mentioned. Examples are described for applications in the areas of composites, porous solids and coatings. Opportunities for many new applications are presently available for exploitations.

DiffServ 환경에서 Mobile Xcast 지원에 관한 연구

배진호,김태수,이광휘 국립7개대학공동논문집간행위원회 2003 공업기술연구 Vol.3 No.-

In the third generation of mobile computing environment, the applications that are compatible with small members of group in which the applications join the multicast sessions such as Internet phone, video conference and networked games are more prevalent. However, since the traditional multicast mechanisms supporting the mobile computing are suitable for large members of group in the multicast session, we need to consider a new mechanism to complement them. Therefore, in this paper we suggest a new multicast model that adopted explicit multicast(xcast), which has more gradual deployment with legacy Internet backbone. This proposed model is cost-effective and more scalable and guarantees the QoS in mobile computing.

식이 단백질의 급원에 따른 당뇨쥐의 혈당 및 혈청지질에 미치는 영향

이수진,김영진,박수정,김희정,이윤희,유영상 동아시아식생활학회 1997 동아시아식생활학회지 Vol.7 No.2

This study was designed to find out the effects of soybean protein and milk protein between nondiabetic and diabetic rats. The experimental results are summarized as follows. 1. Total food intake was higher in diabetic soybean protein group than other groups but it was not significant. 2. The change of body weight was lower in diabetic soybean protein group than other groups and the soybean protein was effective to maintain the ideal body weight. 3. The effects of lowering total cholesterol and glucose in serum was higher in soybean protein groups than the milk protein groups.

효과적인 다차원 분석을 지원하는 스트레드시트 방식의 OLAP 인터페이스 설계 및 구현

윤민희,김진호,문양세 강원대학교 정보통신연구소 2006 정보통신논문지 Vol.10 No.-

OLAP systems support effectively data analysis over a large volume of business data to make decisions for an enterprise. In order to process data analysis efficiently, OLAP systems pre-compute the summary of business data over various dimensions and store them into data warehouses. Several specialized tools have been developed to display and to browse the results of complex analytical queries on data warehouses. In this paper, we developed a spreadsheet-like tool to support OLAP operations and to browse the results of analytical queries. Spreadsheet is one of the most popular and user-friendly data analysis tool. It also has lots of advantages, which is interactive, easy to learn, etc. Thus this paper implemented an OLAP tool using spreadsheet-style interface to analyze large OLAP data on World-Wide Web. Through this tool, users can process OLAP activities easily and effectively by using the same ways as well-known shreadsheet tools like Microsoft Excel.

Sol-gel법을 이용한 미세공 실리카 세라믹의 기공구조 변화에 관한 연구

이진휘,연만형,정은정,박노혁 서울産業大學校 1996 논문집 Vol.43 No.1

솔-젤법에 의하여 제조된 미세공 실리카 세라믹에 대하여 N₂-adsorption isotherm 및 TEM에 의하여 기공구조 변화를 조사하였다. Group 1, 2 및 3의 경우 물의 양이 각각 11, 5.5 및 3.8mole까지는 급격히 surface area의 증가를 보이다가 그 이후에는 완만한 상승을 보이는데, 이것은 앞의 실험에서 보인[4.5]gelation time 및 FT-IR의 실험결과와 일치하는 것이다. 서로 다른 물의 양에 대하여 BET surface area와 Cumulative surface area의 차이가 Group 1서 Group 3으로 옮아감에 따라 커지는 것은 용매의 양은 감소하는 반면 TEOS의 양 증가로 인하여 물과 TEOS의 반응이 원활하지 못한 결과로 덜 발달된 polymer에 기인한 작은 particle에 의하여 형성된 작은 기공들에 기인한 것으로 사료된다. 이와같은 기공구조는 TEM의 결과에 의하여 확인할 수 있다. Group A에서 E쪽으로 갈수록 물의 양의 증가에 기인하여 surface area는 증가하며, Group a에서 d쪽으로 갈수록 물의 양의 감소에 기인하여 surface area는 감소한다. N₂-adsorption isotherm and TEM were used to investigate the micro-porous silica ceramic prepared by sol-gel process to find the structural changes of pores. In the case of Group 1, 2 and 3, the drift of the surface area increased steeply till the amount of water 11, 5.5 and 3.8 moles individually and after that showed increased smoothly. It is the same results as the gelation time and the FT-IR[4.5]. It is the reason that the differences of BET and Cumulative surface area become larger proportionally as moving from Group 3 that the reaction of water and TEOS is less active, caused by using decreased quantity of water but increased TEOS, and therefore the smaller pores by the smaller particles were formed. It was identified by TEM. The surface area is increased by the increased water as moving from Group A to Group E, and decreased by the decreased water as moving from a to e.

Sol-Gel법을 이용한 Silica Membrane의 제조 공정에 관한 조사연구

이진휘,이준,김화중 서울産業大學校 1990 논문집 Vol.32 No.1

졸 -겔 공정에 대한 일반적인 문헌들을 검토하였다. 이와같은 문헌들을 성공적으로 적용하려면 공정에 대한 여러가지 단계와, 영향을 미치는 인자들에 관한 체계적인 이해가 먼저 요구된다. 겔화하는 동안 구조 및 미세구조의 전개에 영향을 미치는 몇가지 인자와 더불어 건조 및 열처리 조건을 조사하였다. 혼합물, 다공성 고체 및 코팅분야에 적용하기 위한 몇가지 예들을 기술하였다. 현재 이 분야의 발전에 기여할 새로운 응용기회는 많다. The general informations of the sol-gel process are reviewed. Successful applications are dependent on sufficient scientific understanding of the various stages and factors of the process. A number of factors governing the development of the structure and microstructure during gelation and subsequent drying and firing conditions are mentioned. Examples are described for applications in the areas of composites, porous solids and coatings. Opportunities for many new applications are presently available for exploitations.

감초로부터 Glycyrrhizin 추출

이진휘,장향동,최하영,서동호,이성미,김경하 서울産業大學校 1998 논문집 Vol.47 No.1

Glycyrrhiza uralensis계의 원감초 뿌리에서 추출도는 감초는 여러가지 질병의 약제로 널리 이용되어 왔다. 그 주성분인 gliycyrrhizin은 항염증 활성 및 anti-allergic activity를 갖고 있으며 이러한 생리활성은 aglycone β-gliycyrrhetinic acid 의 활성에 의한 것으로 알려져 있고, β-gliycyrrhetinic acid는 steroid 구조와 유사하며, 면역조절 특성을 갖는 것으로 인식되고 있다. 이러한 β-gliycyrrhetinic acid 의 면역조절 활성에 기여하는 인자와 그 경로에 대하여 조사된 바 있다 Glycyrrhizin은 감초뿌리의 주성분중 하나이며, 그외에도 surgars(14%), starches(30%), flavonoids, saponoids, amonoacids, gums 및 essential oil 등을 포함하고 있다. Licorice, the root extract of Glycyrrhiza uralensis, is used as a medicine for various diseases. Antiinflammatory as well as anti-allergic activities have been attributed to one of its main constituents, glycyrrhizin. These activities are mainly ascribed to the action of the aglycome β-glycyrrhetinic acid. βGlyeyrrhetinic acid has a steroid-like structure and is believed to have immunomodulatory properties, To determine whether interference with complement functions may contribute to the immunomdulatory activity of β-glycyrrbetinic acid. its effect on the classical and alternative activation pathways of human complement were investigated. The main constituent found in the root is glycyrrhizin. The plant also contains various sugars(14%), starches(30%), flavonoids, saponoids, aminoacids, gums, and essential oil etc.