Correlation Between Primary Si and Silicide Refinement Induced by Ultrasonic Treatment of Multicomponent Al–Si Alloy Containing Ti, Zr, V, and P

Jae‑Gil Jung,Young‑Hee Cho,Tae‑Young Ahn,Jae‑Hee Yoon,Sang‑Hwa Lee,Jung‑Moo Lee 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.5

The correlation between primary Si and silicide refinement induced by ultrasonic treatment (UST) of multicomponent Al–Sialloy containing Ti, Zr, V, and P was investigated. UST significantly refined the primary Si phase owing to cavitation-inducedwetting and deagglomeration of MgAl2O4particles. Lowering the UST finish temperature caused deterioration of the degreeof primary Si refinement, instead leading to silicide refinement. Cavitation-induced silicide nucleation on wetted MgAl2O4consumed the MgAl2O4particles, particularly in the case of primary Si nucleation. Similarly, the formation of an AlP phaseon the silicide phase reduced the nucleation efficiency of the AlP phase. Poisoning of the MgAl2O4and AlP phases by thesilicide phase was responsible for the deterioration in primary Si refinement. Room-temperature tensile strength and hightemperatureelongation were increased by UST and were dependent on the size of primary Si.

구리 지역에서 조사한 고혈압의 인지도, 치료률 및 관리률

홍철호,김순길,홍택원,이제,신진호,이재웅,김경수,김정현,임헌길,이방헌 대한간질학회 2003 대한간질학회지 Vol.9 No.1

접촉각 측정을 통한 Alkanethiol로 표면 처리한 은 분말의 표면 특성 연구

이길재,신승일,오성근 한국공업화학회 2004 공업화학 Vol.15 No.1

은 분말을 alkanethiol로 표면 처리한 후, alkanethiol의 탄소 개수 변화에 따른 은 입자의 표면 특성변화를 접촉각 측정을 통해 연구하였다. 이때 은 입자 표면에 alkanethiol의 흡착여부를 DRIFT (diffuse reflectance infrared fourier transform) spectrum를 통해 확인하였다. 접촉각은 Washburn 식을 바탕으로 한 liquid penetration 방법으로 측정하였고, 이 측정법의 보완을 위해 분말에 압력을 가하여 원판형태로 만들어 그 표면에서 접촉각을 측정하는 sessile drop 방법을 함께 사용하였다. 그 결과 순수한 은 입자의 물에 대한 접촉각은 두 가지 방법에 대해 각각 58°, 40° 나왔고, 다양한 탄소개수(C_(4)-C_(12))의 alkanethiol로 표면 처리한 입자는 모두 90° 이상의 결과를 얻었다. 즉 alkanethiol로 처리한 은 입자의 표면이 소수성으로 변했음을 의미한다. 여기서 처리한 alkanethiol의 탄소개수가 증가할수록 접촉각은 계속 증가했으나, 접촉각의 증가 폭은 상대적으로 점차 감소하였다. Contact angles of silver powders were measured for investigation of surface properties of silver particles as changing alkyl chain length of alkanethiol. Silver powders were modified by various alkanethiol (C4∼C12). Adsorption of alkanethiol on silver particles was confirmed by DRIFT (diffuse reflectance infrared fourier transform) spectrum. Contact angles were measured by liquid penetration method based on Washbum equation and sessile drop method on tablet of compressed powder. In result. the value of contact angles on water were 53°, 40°about two method. Contact angles of surface treated particles by alkanethiol of varied alkyl chain length were larger than 90°. Because of bonding between silver and sulfur in alkanethiol, silver surface was surrounded by alkyl groups of alkanethiol. Surface properties of silver particles were increased on hydrophobicity with alkyl chain length of alkanethiol. In comparison with increase of contact angle accordingto increase of alkyl chain length of alkanethiol. the widths of increasing contact angle were relatively decreased.

학내망을 이용한 인트라넷 설계 및 구현

이재동,이병길 경남대학교 정보통신연구소 1999 연구논문집 Vol.1 No.-

본 논문은 학교 내에 설치된 학내망을 이용하여 인트라넷을 구축하고 웹 서버 컴퓨터에 공유시켜서, 학생들이 인터넷을 통하여 공간적·시간적 제약을 받지 않고 학습활동을 함에 있어 도움을 주고자 하는데 그 목적이 있다. 또한 이 논문에서는 획일적인 기존 수업 방식을 탈피한 인터넷을 활용한 효과적인 수업 방식을 강구해 보고자 하였다. 최근에는 웹을 기반으로 하는 응용 프로그램이 다양하게 출시되고 있고, 동시에 처리해야할 데이터의 양과 멀티미디어 자료의 양이 점점 많아지고 있다. 따라서, 본 논문에서는 많은 자료를 효율적으로 관리하기 위한 데이터베이스 시스템의 개발, 웹과 데이터베이스 통합, 단순 데이터만 받을 수 있는 기존 웹 방식의 탈피 등을 통하여, 학생들이 수업에 적극적으로 참여할 수 있는 동적인 정보 교환 시스템인 E-School 시스템 개발을 통하여 학생들의 학습 효과를 극대화시키고자 한다. The purpose of this paper is to maximize the learning activity of students, establish intranet taking advantage of school network and join various educational informations to web server computer through internet without being spatial and time restriction. It is also going to seek the effective teaching method through internet to get out of the old established one. Recently application programs based on web were developed in various areas, and multimedia data which have to be processed at the same time are enlarging. So, using the database system and the combination of web and database, and the getting out of the old established way of web, we developed E-School System with dynamic data exchange for students to help participate in the class with active and positive manner.

원심모형시험에 의한 복개터널 복공의 토압특성에 관한 연구

이명욱,박병수,정길수,유남재 江原大學校 産業技術硏究所 2004 産業技術硏究 Vol.24 No.B

This thesis is results of experimental works on the behavior of the cut-and-cover tunnel. Centrifuge model tests were performed to simulate the behavior of the cut-and-cover tunnels having cross sections of national road and subway tunnels. Model experiments were carried out with changing the cut slope and the slope of filling ground surface. Displacements of tunnel lining resulted from artificially accelerated gravitational force up to 40g of covered material used in model tests, were measured during centrifuge model tests. In model tests, Jumunjin Standard Sand with the relative density of 80 % and the zinc plates were used for the covered material and the flexible tunnel lining, respectively. Basic soil property tests were performed to obtain it's the property of Jumumjin Standard Sand. Shear strength parameters of Jumunjin Standard Sand were obtained by performing the triaxial compression tests. Direct shear tests were also carried out to find the mechanical properties of the interface between the lining and the covered material. Compared results model tests estimation with respect to displacements of the lining.

자동차용 시로코팬의 유동특성에 관한 연구

이행남,박길문,이덕구,정한별,김건일,설재림 朝鮮大學校 機械技術硏究所 2005 機械技術硏究 Vol.8 No.1

The sirocco fan is used to get low noise, and it has been applied to a lot of industry field like the heat engine, the fluid instrument power plant, the food industry, environment industry etc... because there are not problems even it is mixed with a any kind of liquid, gas, and solid. The flow characteristics in sirocco fan are investigated by PIV. The experiment using PIV measurement for Test section's flow characteristics acquired velocity distribution, Condition : when sirocco fan in automobile air controller maximum 1450RPM, and a revolution is a variation (l)950RPM, (2)l100RPM, (3) 1250RPM. The agreement a experiment shows the validity of this study and the results of this study would be useful to the engineers who design for the flow systems

작업의 특성에 종속되는 병렬기계의 일정계획을 위한 발견적 기법

이동현,이경근,김재균,박창권,장길상 한국경영과학회 2000 經營 科學 Vol.17 No.1

In the real world, situations that some jobs need be processed only on certain limited machines frequently occur due to the capacity restrictions of machines such as tools, fixtures, or material handing equipment in this paper, we consider n-job, non-preemptive and m parallel machines scheduling problem having two machines group The objective function is to minimize the sum of earliness and tardiness with different release times and due dates The problems is formulated as a mixed integer programming problem The problem is proved to be NP-complete Thus, a heuristic is developed to solve this problem To illustrate its suitability and efficiency, a proposed heuristic is compared with a genetic algorithm and tabu search for a large number of randomly generated test problems in ship engine assembly shop Through the experimental results, it is showed that the proposed algorithm yields good solutions efficiently

수문지질 특성에 의한 갈수량의 변화

이길영,허재영,박승기 大田大學校 産業技術硏究所 1996 산업기술연구소 論文集 Vol.7 No.2

The regional unbalance of water quantity and the deterioration of water quality become pending problems that should be solved. Although monthly streamflow data have been used in most water resources plannings to cope with the problems, for more effective management of confined water resources the exact calculation of daily droughtflow is essential. In this study, the droughtflows at Backokpo watershed in Han River were measured from May 1993 to May 1994 and the relations between drogughtflow and the hydrogeological character of the watershed were figured out.

可動性關節 捻挫指壓占에 關한 硏究

李栽吉 군산대학교 1993 群山水産專門大學 硏究報告 Vol.27 No.1

The health care consists fo the health exemination, preventive medicine, therapeutics epidemic prevention, first-aid treatment, etc. This thesis studies the first-aid treatment for the bone-inframmation in the joints of the body. Also, this thesis, being on the basis of the acupuncture and moxacatery, studies the treatment effects of the finger-pressure therapy for the bone-inflammation in the shoulder, finger, ankle, and the disjoint of the shoulder as a first- aid treatment.

대청호 대전취수탑 수역에 있어서의 수질특성에 관한 연구

이길영,노장성,허재영 大田大學校 産業技術硏究所 1995 산업기술연구소 論文集 Vol.1995 No.9

In order to survey the cause of the eutrophication in Taechong reservoir, the water body around Taejon intake tower were divided into 5 groups, and the samples were taken to analyse the quality of water, deposits and algae. The relationship between the water quality and the meteorological factors in the study area was investigated and the contamination mechanism in the reservoir was explained. Finally, the relation between T-N concentration and inflow volume was established.