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.

고소성 해성점토지반의 압축지수에 대한 비교 연구

정길수,박병수,홍영길,유남재 江原大學校 産業技術硏究所 2005 産業技術硏究 Vol.25 No.A

In this paper, for the highly plastic marine soft clay distributed in west and southern coast of Korean peninsula of Kwangyang and Busan New Port areas, correlation between compression index and other indices representing geotechnical engineering properties such as liquid limit, void ratio and natural water content were analyzed. Appropriate empirical equations of being able to estimate the compressibility of clays in the specific areas were proposed and compared with other existing empirical ones. For analyses of the data and test results, data for marine clays were used from areas of the South Container Port of the Busan New Port, East Breakwater, Passenger Quay, Jungma Reclamation and Reclamation Containment in the 3rd stage in Kwangyang. In order to find the best regression model by using the commercially available software, MS EXCEL 2000, results obtained from the simple linear regression analysis, using the values of liquid limit, initial void ratio and natural water content as independent variables, were compared with the existing empirical equations. Multiple linear regression was also performed to find the best fit regression curves for compression index and other soil properties by combining those independent variables. On the other hands, another software of SPSS for non-linear regression was used to analyze the correlations between compression index and other soil properties.

REF SILL OTR-R/L 차체판넬 스템핑공정에서의 금형개발에 관한 초기 연구

정동원,황재신,안현길 濟州大學校 海洋硏究所 2004 해양과환경연구소 연구논문집 Vol.28 No.1

Finite element method is very effective method to simulate the forming Processes with good prediction of the deformation behaviour. For the finite element modeling of sheet mental forming the accurate tool model is required. Due to the geometrical complexity of real-size Part stamping tools it is hard to make FE model for real-size auto-body stamping parts. In this paper, it was focussed on the drawability factors on auto-body panel stamping by AUTOFORM with using tool planing alloy to reduce law price as well as high precision from Design Optimization of die. According to this study. the results of simulation will give engineers good information to access the Design Optimization of die.

Delay Line을 이용한 1차 미분 임펄스 발생기 설계

김은정,임재현,김길겸,김학선 한밭대학교 정보통신전문대학원 2004 정보통신전문대학원 논문집 Vol.2 No.1

본 논문에서는 UWB (Ultra-WideBand)시스템에 사용되는 짧은 폭의 임펄스 발생기를 설계하였다. SRD와 두개의 단락된 전송 선로를 이용 하였다. 단락된 전송 선로는 시간 지연과 위상의 반전을 효과적으로 제공 한다. RC 미분기 대신에 단락된 전송 선로(Delay Line)을 이용하여 1차 미분 임펄스를 발생시켰다. 시뮬레이션을 통해 700psec의 펄스폭과 600mV(p.p)의 진폭, 펄스 모양의 좋은 대칭성을 확인하였고 또한, 펄스 주변의 떨림 현상이 거의 발생하지 않았다. In this paper, we have designed impulse generator of short pulse width for UWB(Ultra-Wide band) system using SRD and two short-circuited stubs. The short-circuited stub provides good time delay and reverse of phase. The first derivative impulse was generated by using short-circuited stub(Delay Line) instead of RC differentiator. A first derivative impulse of 700 psec pulse duration, 600mV(p.p) pulse amplitued, and good symmetry has been demonstrated though simulation. Also, there are extremely small amount of ringing around the first derivative impulse.

DNA 증거의 집단유전학적 분석을 위한 SAS시스템

이효정,이혜승,한길로,이재원,황적준 大韓法醫學會 2000 대한법의학회지 Vol.24 No.1

DNA analysis has become one of the most powerful tools in forensic inference for human identification and is now used worldwide. It is used to be statistical technique for the individual identification of a civil and criminal action. The purpose of this article is computerization of the statistical technique for the population study and DNA evidence analysis. The system using SAS/AF and SAS/SCL is the graphic user interface and the correspondence of the changed experimental circumstances

제품보호용 포장재 개발

김정필,강재현,박대연,유성구,서길수 영남대학교 공업기술연구소 2000 工業技術硏究所論文集 Vol.28 No.1

The environment to which a packaged-product is exposed, during handling and transportation, very often includes temporary storage. In the interest of conserving warehouse cube, packaged-products are stacked upon one another to a height which far exceeds that possible in a railcar, truck-trailer, aircraft or other conveyance. the hight to which the height to which a packaged-product may be stacked will vary depending upon the warehouse ceiling height-seldom over twenty feet. This procedure for expirimental covers testing of packaged-products weighing under 100 pounds when prepared for shipment. The BASIC requirements of this procedure consist of vibration and drop tests-which must be performed in that sequence.

폐전선 피복재 건류탄을 이용한 제강분진처리를 위한 기초연구

황용길,이상화,이성룡,정석수,최재신,조충형 東亞大學校 1995 東亞論叢 Vol.32 No.-

Distilled carbon from waste electric wire coated by vinyl is used to recover valuable metal such zinc, lead and iron in dust. Pemeability and compressive tests are who done to present basic data on extraction of zinc in dust. Experimental results obtained from sintering property of steelmaking dust, distilled carbon from waste electric wire coated by vinyl and waste pulp sludge mixture briquet at various sintering temperature are as followings; Permeability is increased as increasing distilled carbon and pulp amount at higher temperature than room temperature condition. Compressive strength at room temperature is increased as increasing distilled carbon and decreasing waste pulp amount, but decreased as increasing temperature and waste pulp amount. Weight Loss reaction experiment is increased a increasing distilled carbon and waste pulp amount. ZnO and Fe₃O₄ are obtained from sample containing ZnO, Fe₂O₃ and ZnO at 800℃. Permeability test at 500℃ and 800℃ did not well, because of 13.3% CaO in distilled carbon. Sample because semmi melted state at 1000℃. Distilled carbon obtained from waste electric wire showed effect of reduction and flux material.

추출조건에 따른 다시마 추출액의 특성에 미치는 물리적 특성의 영향

허상선,정재용*,박영호,주길재,최용희* 경북대학교 농업과학기술연구소 1999 慶北大農學誌 Vol.17 No.-

The objective of this research was to characterize viscosity of sea tangle extract isolated from sea tangles in Korea to obtain basic data for production of dietary fiber materials with new functional properties. The viscosity of sea tangle extract was increased as the the extraction time increased. However, these values increased inginficantly up to 1 hour of extraction time and then slow increased in case of hot water extraction and enzymatic hydrolyzed sea tangle extract. As for addition of sugar and salts, the values of viscosity of sea tangle extract was very low in the additon of EDTA-2Na regardless of concentration. But in case of sucrose and NaCl, the viscosity of sea tangle extract were tended to decreased up to 2.5% concentration.

모래다짐말뚝 개량폭에 따른 보강효과에 관한 연구

김시운,정길수,박병수,유남재 江原大學校 産業技術硏究所 2005 産業技術硏究 Vol.25 No.A

In this research, centrifuge model experiments and numerical approach of finite element method to analyze experimental results were performed to investigate the behavior of improved ground with sand compaction piles. One of typical clay minerals, kaolinite powder, were prepared for soft ground in model tests. Jumunjin standard sand was used to sand compaction pile installed in the soft soil. In order to investigate the characteristics of mechanical behavior of sand compaction piles with low replacement ratios, centrifuge model experiments with the replacement ratio of 40%, changing the width of improved area with respect to testing results the width of surcharge loads, were carried out to obtain of bearing capacity, characteristics of load-settlement, vertical stresses acting on the sand pile and the soft soil failure mechanism in improved ground.

방향성 응고된 이상형 스테인레스강에서 질소첨가가 미세조직에 미치는 영향

최병학,정병길,김진우,고석민,이재현,김상식,김성준 국립7개대학공동논문집간행위원회 2001 공업기술연구 Vol.1 No.-

Microstructures in the directionally solidified duplex stainless steels were investigated in order to understand the effect of nitrogen addition. It was found that the addition of nitrogen causes formation of fine precipitates in a matrix and segregation phases of nitrogen in the α/γ interface. Both the fine precipitates and the segregation phases were identified CrN(fcc, a=4.16A˚), which has the coherent phase relationship with bcc α matrix of (200) CrN // (0 1￣ 1) α and (1￣1￣ 1) CrN // ( 3￣ 2￣ 1) α.