황산용액에서 플라즈마 용접 및 열처리 조건이 티타늄의 부식특성에 미치는 영향

김창규(Chang-Kyu Kim),강현후(Hyun-Hoo Kang),박대주(Dea-Ju Park),김태원(Tea-Won Kim) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11

The influences of plasma weld conditions together with heat treatments on the corrosion behavior of titanium in sulfuric acid were analyzed. Several tests were conducted by means of electrochemical polarization and immersion experiments to determine the corrosion rate of titanium materials. The rate of corrosion was then evaluated in terms of the values of corrosion potential, passivation current density and weight loss of the materials, respectively. Six types of specimen were used in the test. As shown in the results, the most effective weld conditions including processing time and value of current with heat treatment could be determined in sulfuric acid environment.

연주롤용 육성용접 재료의 고온마모 및 부식특성에 미치는 Nb, V의 영향

김창규(C. G. Kim),황동수(D. S. Whang),윤재홍(J. H. Yoon),강창룡(C. Y. Kang),곽희환(H. H. Kwak) 한국동력기계공학회 2004 동력시스템공학회지 Vol.8 No.3

GIS를 이용한 5대 범죄의 공간적 특성 분석

김창규(Kim, Chang Kyu),강인준(Kang, In Joon),박동현(Park, Dong Hyun),최치영(Choi, Chi Young) 한국측량학회 2014 한국측량학회 학술대회자료집 Vol.2014 No.4

GIS와 상관·회귀분석을 활용한 5대 범죄의 특성분석

김창규(Kim, Chang Kuy),강인준(Kang, In Joon),박동현(Park, Dong Hyun),김상석(Kim, Sang Seok) 대한공간정보학회 2014 대한공간정보학회지 Vol.22 No.3

현대사회의 시민들은 쾌적하고 안전한 생활공간과 환경을 희망한다. 그러나 현대사회로 접어들수록 급격하고 복잡한 변화를 맞이함으로써 지능적이고 고도화된 범죄가 빈번히 발생하고 있으며, 그 범죄들에 대응하기 위하여 다각적으로 노력이 행해지고 있다. 특히, 실생활에서 가장 많이 발생하고 두려움을 갖게 되는 5대 범죄(살인, 강도, 강간, 폭력, 절도)는 매우 위협적인 요소로 과학적인 대응방안이 필요하다. 이에 본 연구에서는 부산광역시 금정구일대의 범죄 자료들을 바탕으로 5대 범죄에 대응하기 위하여 범죄유형별 빈도수를 분석하고 상관분석과 회귀분석을 이용하여 범죄 요인과 범죄 사이의 공간적 특성을 분석하였다. People in the modern society want to live under safe and comfortable circumstances. As our society, however, is sharply developing, crimes are getting smarter and more difficult to treat. Above all, they often take place around us, and we are trying to cope with them variously in order to make our lives more comfortable and safer. In particular, five major crimes(Murde, Robber, Rape, Violence, Theft ) that most frequently occur in the real life are very threatening and fearful so it is necessary to deal with them with “the scientific method.” In this study, therefore, we searched the frequency of crime by its type and analyzed spatial characteristics between crimes and criminal factors by using regression analysis and correlation analysis based on the crime data that has occurred around Geumjeng-gu, Busan so that we can confront five major crimes.

GIS를 이용한 이동식 건설장비의 최적 이동경로 선정 및 탄소배출량 예측 전략

김창규(Kim, Chang Kyu),강인준(Kang, In Joon),박동현(Park, Dong Hyun) 한국측량학회 2013 한국측량학회 학술대회자료집 Vol.2013 No.4

석면 비산방지제의 성능평가 시험 연구

김창규(Chang-Kyu Kim),하광태(Kwang-Tae Ha),강미혜(Mi-Hyae Kang),정숙녀(Sook-Nye Chung),김지성(Ji-Sung Kim),김가연(Ga-Yeon Kim),정종흡(Jong-Heub Chung),어수미(Soo-Mi Eo),정권(Kweon-Jung) 대한환경공학회 2018 대한환경공학회지 Vol.40 No.7

본 연구의 목적은 석면 비산방지제의 성능을 평가하는 장치기술을 개발하여 현행 공정시험방법을 효율적으로 개선하고자 하였다. KS의 석면 비산방지제 시험방법(KS M 2757:2014)중 섬유비산 시험방법의 공기분사방식과 공기분사구의 압력조절방식을 개선하여 시험의 정확성을 증대시켰다. 공기분사방식을 1-way에서 2-way로 적용한 결과, 측정된 석면 평균농도는 0.051 f-PCM/㏄로서 기존의 1-way방식(0.012 f-PCM/㏄)보다 약 4배 높아 석면 검출능력이 향상되었다. 또한 공기분사구 압력조절방식 개선을 위해 표면압력측정부를 적용한 결과, 시험체 표면에 항상 일정한 풍속 약 10 ㎧를 유지하였다. 그러나 표면압력측정부가 없는 경우에는 구동모터의 이격거리 변화 때문에 풍속이 변화하여 각각 6.6, 4.8, 3.7 ㎧로 일정하지 못하였다. 그러므로 2-way공기분사방식을 통해 시험체에 충분한 유량을 사각지대 없이 공급하여 석면 검출능력을 높이고, 표면압력 측정기능을 통해 시험체에 일정한 풍속을 유지시킴으로써 시험방법의 정확성과 효율성을 개선하였다. The purpose of this study is to develop a device to evaluate the performance of asbestos stabilizers and improve the accuracy of the process test method. We increased the accuracy of the test method by applying the air injection method and pressure control method of the nozzle in the testing methods for performance evaluation of encapsulants in asbestos-containing building materials (KS M 2757:2014). As a result of applying the air injection method, the average concentration of asbestos obtained using the 2-way method was 0.051 f-PCM/㏄, which is approximately four times higher than that obtained using the 1-way method (0.012 f-PCM/㏄). In addition, as a result of applying the pressure control method, a constant air velocity of approximately 10 ㎧ was maintained at the air injection port to the specimen by using the surface pressure sensor. In the absence of the surface pressure measuring part, the air velocity was changed to 6.6, 4.8, and 3.7 ㎧ respectively, owing to the change of the travel distance of the turning motor. Therefore, the accuracy and efficiency of the test method were improved by supplying 2-way air injection to the specimen without blind spots and maintaining a constant air through the surface pressure sensing function.

대기중 라돈자핵종 농도의 일일 및 계절적 변화와 기상인자가 미치는 영향

이동명,김창규,노병환,이승찬,강희동,Lee, Dong-Myung,Kim, Chang-Kyu,Rho, Byung-Hwan,Lee, Seung-Chan,Kang, Hee-Dong 대한방사선방어학회 2000 방사선방어학회지 Vol.25 No.4

1999년 7월부터 2000년 7월까지 대전지역에서 전알파/베타 대기부유진 연속모니터링 시스템과 기상측정 시스템을 이용하여 대기중 라돈자핵종 농도에 대한 시간별, 일별, 계절별 변동특성을 조사하였으며 동시에 기상인자가 미치는 영향을 고찰하였다. 그 결과 대기중 라돈자핵종의 일일평균 평형등가농도$(EEC_{Rn})$ 분포는 산술평균 $11.8{\pm}5.86Bqm^{-3}$ 과 기하평균 $10.3{\pm}4.57Bqm^{-3}$이었으며 일일 평균농도의 변동계수는 약 50%정도이었다. 매 30분마다 측정한 라돈자핵종의 평형등가농도는 최소 $0.80Bqm^{-3}$에서 최대 $43.3Bqm^{-3}$ 까지 하루 중 측정시간과 그때의 기상조건에 따라 변하였으나, 일일변동의 양상은 일출시점과 일몰시점에서 각각 최고농도와 최저농도를 반복하는 주기적인 양상을 보였다. 대전지역에서의 평형등가농도는 계절적으로 여름철이 낮고 늦가을이 높은 변동양상을 보여주었으나, 대기중 라돈자핵종 농도의 계절적 변동양상은 측정지역에 따라 달라질 수도 있을 것으로 예상된다. 대기중의 라돈자핵종 농도는 그 지역의 국지적 기상특성에 크게 좌우되었다. 특히 풍속이 $6msec^{-1}$ 이상이 되면 대기중의 라돈자핵종 농도는 $5Bqm^{-3}$이하로 급격히 떨어지는 반면에 대기중의 라돈자핵종 농도가 $30Bqm^{-3}$ 이상인 날은 풍속이 $1msec^{-1}$ 이하의 매우 고요한 날이었다. Continuous measurements of radon progeny concentrations in the open atmosphere and measurements of meteorological parameters were performed in Tajeon, using a continuous gross alpha/beta aerosol monitor and a weather measuring equipment between July 1999 and July 2000. These data were analyzed for half-hourly, daily, and seasonal variations. The distribution of daily averaged equilibrium equivalent radon concentration$(EEC_{Rn})$ had an arithmetic mean value of $11.3{\pm}5.86Bqm^{-3}$ with the coefficient of variation of about 50% and the geometric mean was $10.3Bqm^{-3}$. The $EEC_{Rn}$ varies between 0.83 and $43.3Bqm^{-3}$, depending on time of day and weather conditions. Half-hourly averaged data indicated a diurnal pattern with the outdoor $EEC_{Rn}$ reaching a maximum at sunrise and a minimum at sunset. The pattern of the seasonal variation of the $EEC_{Rn}$ in Taejon had a tendency of minimum concentration occurring in the summer(July) and maximum concentration occurring in the late autumn(November). But the seasonal variation of the $EEC_{Rn}$ is expect to vary greatly from place to place. The outdoor $EEC_{Rn}$ was highly dependent on the local climate features. Particularly the $EEC_{Rn}$an rapidly drops less than $5Bqm^{-3}$ in case of blowing heavily higher than wind speed of $6msec^{-1}$, reversely the days with more than $30Bqm^{-3}$ were at a calm weather condition with the wind speed of lower than $1msec^{-1}$.

오스템퍼드 구상흑연 주철의 기계적 성질 및 파괴특성에 미치는 오스템퍼링 온도의 영향

강창룡,김창규 ( C . Y . Kang,C . G .Kim ) 한국열처리공학회 1994 熱處理工學會誌 Vol.7 No.4

This study was performed to investigation the effect of austempering temperature on the mecanical properties and fracture Characteristic of the ductile cast iron with contains Cu and Mo. The obtained results of this study were as follows; Microstructure of austemped ductile cast iron obtained by sustempering were low bainite with some martensite at 250℃, mixture of low and upper bainite at 300℃ and upper bainite at 350℃. With increasing austempering temperature, yield strength, tensile strength and hardness decreased, while the elongation and impact absorption energy increased. With increasing austempering temperature, fracture toughness value increased and mainly controlled by bolume fraction of retained austenite. The volume fraction of retained austenite increased and the fracture surface obtained fibrous and dimple with increasing austempering temperature.

오스템퍼드 구상흑연주철의 파괴특성에 미치는 오스템퍼링 온도의 영향에 관한 연구

박준훈,강창룡,김창규 ( Jun Hoon Park,Chang Yong Kang,Chang Gyu Kim ) 한국주조공학회 1995 한국주조공학회지 Vol.15 No.2

N/A This study was performed to investigate the effect of austempering temperature on the mechanical properties and fracture characteristics of the ductile cast iron with Cu, Mo and Cu, Mo, Ni. The results obtained from this study are summarized as follows; Microstructures of Cu-Mo and Cu-Mo-Ni ductile cast iron by austempering were obtained low bainite with some martensite at 250℃, mixture structure of upper and low bainite obtained at 300℃ and upper bainite obtained at 350℃. Tensile, impact and fracture toughness properties were remarkably controlled by retained austenite. With increasing austempering temperature, tensile and yield strength, hardness decreased, while the elongation and impact absorption energy, fracture toughness increased. With adding Ni, tensile and yield strength increased and elongation, facture toughness and impact absorption energy decreased. Retained austenite increased with increasing austempering temperature and the fracture surface were shown mixture structure of fibrous and dimple.

25Cr - 7Ni - 3Mo 2 상 스테인리스강의 미세조직과 기계적성질

강창룡,김효정,김창규,김익수,주동원,성장현 ( C . Y . Kang,H . J . Kim,C . G . Kim,I . S . Kim,D . W . Joo,J . H . Seong ) 한국열처리공학회 1998 熱處理工學會誌 Vol.11 No.3

N/A This study was carried out to investigate the influence of variations in the temperature and time of isothermal heat treatment, applied stresses and prestrain on the isothermal transformation behavior of γ and σ phases and mechanical properties of 25Cr-7Ni-3Mo duplex stainless steel. The precipitation of γ and σ phases through isothermal heat treatment showed the type curves with a certain incubation period, the curve migrated to in a short period of time and the amount of precipitation increased with decreasing isothermal heat treatment temperature. Under the state of isothermal transformation, the precipitation of γ and σ phases was stimulated by applied stress, with increasing applied stress, the curves migrated to in a short period of time and also observed that the application of stress has a greater influence on the amount of σ precipitation than that of γ precipitation. The precipitation of γ and σ phases was stimulated by cold and warm rolling before isothermal heat treatment and precipitation of γ and σ phases has a greater influence on the warm rolling than cold rolling. The tensile strength and hardness increased with increasing cold and warm rooling reduction ratio.