• 대한안전경영과학회지
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• 제15권1호
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• pp.283-292
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• 2013

This paper aims to propose a new steps of hypothesis testing using analysis process and improvement process in the six sigma DMAIC. The six sigma implementation models proposed in this paper consist of six steps. The first step is to establish a research hypothesis by specification directionality and FBP(Falsibility By Popper). The second step is to translate the research hypothesis such as RHAT(Research Hypothesis Absent Type) and RHPT(Research Hypothesis Present Type) into statistical hypothesis such as $H_0$(Null Hypothesis) and $H_1$(Alternative Hypothesis). The third step is to implement statistical hypothesis testing by PBC(Proof By Contradiction) and proper sample size. The fourth step is to interpret the result of statistical hypothesis test. The fifth step is to establish the best conditions of product and process conditions by experimental optimization and interval estimation. The sixth step is to draw a conclusion by considering practical significance and statistical significance. Important for both quality practitioners and academicians, case analysis on six sigma projects with implementation guidelines are provided.

• 자원환경지질
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• 제22권2호
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• pp.103-115
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• 1989

The Tongyoung deposits are epithermal gold and silver bearing quartz-rhodochrosite vein type deposits of late Cretaceous. They occurs in the andesite and tuff breccia member called Gyeongsang basin. Four mineralizations can be distinguished at the mine based on macrostructures. From earlist stage to lastest stage they are: stage I, base-metal quartz vein; stage II, rhodochrosite vein (IIA) and Pb-Zn vein (IIB); stage III, barren quartz vein; stage IV, calcite-ankeritic rhodochrosite veins. Gold and silver mineralizations occur predominantly in the stage I and IIB. Electrum is closely associated with galena, sphalerite and pyrite, and has chemical compositions of 50.98-64.05 atom % Ag. Sphalerite contains 2.09-5.05 mol % FeS and 0.34-2.01 mol % MnS in the stage I, and 2.01-3.41 mol % FeS and 0.21-2.80 mol % MnS in the stage IIB. The FeS and MnS contents are in general correlated, and shows a characteristic zonal arrangement of electrum. It reveals rhat FeS contents of sphalerite which precipitated before electrum, gradually decreases in a grain during its deposition ranging from about 3.3 to 2 mol %. It may be considered from the above data that an increase of $fs_2$ caused by the oxidation of ore forming fluid is more important that the decrease of temperature.

• 한국재료학회지
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• 제3권5호
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• pp.505-513
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• 1993

본 연구는 가시부 전영역에 감광하는 전자사진용 감광체를 만들기 위하여 400nm부근에 흡수파장을 갖는 sunfast yellow와 700nm부근에 흡수파장을 갖는 $\alpha$,$\beta$-copperphthalocyanine의 색소를 산화아연(ZnO)에 흡착분산시켰다. 각종 결합제(Binder)의 감도와 , 산화아연과 결합제와의 조성비에 따르는 변화실험의 결과 5.5:1에서 가장 좋은 결과를 나타냈다. 전자사진 감광체의 적합성을 확인하기 위하여 정전특성과 분광감도를 측정해 본 결과 sunfast yellow와 $\beta$-copper phthalocyanine을 혼합사용한 것이 가장 좋은 감도를 나타냈으며, 이 때 측정된 전자시진감도는 $E_{1:2}$=1440 luxㆍsec이었다. 또한 분광감도 측정결과는 가시부전역에 걸쳐 감도를 감광체임을 확인하였다.