• Communications for Statistical Applications and Methods
• /
• 제7권2호
• /
• pp.403-414
• /
• 2000

A diagnostic tool for testing homogeneity for random effects is proposed in unbalanced linear mixed model based on score statistic. The finite sample behavior of the test statistic is examined using Monte Carlo experiments examine the chi-square approximation of the test statistic under the null hypothesis.

• 대한수학회보
• /
• 제52권3호
• /
• pp.771-788
• /
• 2015

In this note we consider the parametric Marcinkiewicz integrals with mixed homogeneity along polynomials compound curves. Under the rather weakened size conditions on the integral kernels both on the unit sphere and in the radial direction, the $L^p$ bounds of such operators are given by an extrapolation argument. Some previous results are greatly extended and improved.

• 분석과학
• /
• 제6권2호
• /
• pp.207-215
• /
• 1993

소결첨가제($3Al_2O_3{\cdot}5Y_2O_3$, YAG)를 질화규소에 공침방법으로 첨가하여, 통상적인 기계적 혼합 방법으로 준비된 혼합분말에 대한 혼합균일성과 소결 및 기계적 특성을 조사, 비교하였다. 준비된 혼합분말들을 SIMS를 사용하여 분말 표면과 내부의 조성을 비교분석한 결과, 공침법을 사용할 경우 소결첨가제가 $Si_3N_4$ 표면에 피복된 상태로 존재하고 있음을 나타내어 기계적 혼합에 비해 우수한 균일혼합효과를 얻을 수 있음을 확인하였다. 공침법에 의한 균일혼합효과는 $Si_3N_4$ 분말소결체의 소결밀도 및 미세구조의 개선을 수반하여 기계적 강도의 향상을 이룰 수 있음을 확인하였다.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
• /
• pp.824-825
• /
• 2006

Homogeneous microstructures of the PM compacts are difficult to attain when mixed elemental powders are used. This study examined the microstructures of pressed-and-sintered and MIM products that contain Ni and Mo.Ni-rich areas, which were lean in carbon and were soft and were found easily in regular specimens. Gaps or cracks near the Ni-rich or Mo-rich areas were also frequently observed. This problem worsened when Ni and Mo particles were large and were irregular in shape. By using ball milling treatment and ferroalloy powders, the microstructure homogeneity and mechanical properties were improved. The addition of 0.5wt%Cr further improved the distribution of Ni because Cr reduced the repulsion effect between nickel and carbon. With the elimination of Ni-rich areas, more bainites and martensites were formed and mechanical properties were significantly improved.

• Journal of Yeungnam Medical Science
• /
• 제5권2호
• /
• pp.37-45
• /
• 1988

Phospholipase C는 second messenger로서 세포 밖의 signal transduction에 중요한 효소 이다. 본 연구에서 소의 뇌, 자궁 및 고환에서 high performance liquid chromatography(HPLC)를 이용하여 phospholipase C(PLC)를 추출하였으며 뇌에서 3개의 isozyme(F-1, F-2, F-3), 자궁과 고환에서 각각 2개의 isozyme을 얻었고 HPLC에서의 retension time을 구하였다. Homogeneity 검사를 위하여 소 brain의 각 isozyme I, II 및 III에 대한 PLC-monoclonal antibody(Mab)를 affigel에 label 시켰고 결합능(binding capacity)는 73.8~97.5%였다. PLC-Mab와 자궁 및 고환의 PLC isozyme과의 homogeneity 검사에서 binding capacity는 자궁의 F-1은 PLC III가 주이며 F-2는 DEAE column에서는 II가 주이나 phenyl column에선 I과 II가 주이고 고환에선 F-1은 PLC III가 주이고 F-2에서는 PLC II가 주인 것으로 나타났다.

• 대한수학회지
• /
• 제44권3호
• /
• pp.733-745
• /
• 2007

We prove the $L^p(1 boundedness of the parabolic Marcinkiewicz integral with the kernel function $\Omega{\in}L(log^+L)^{1/2}(S^{n-1})$. The result is an improvement and extension of some known results.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
• /
• pp.25-28
• /
• 2006

This study investigated pre-mixed cement combined with ordinary portland cement, BF and SF, in order to manufacture cement binder, which is possible to produce 150MPa ultra high strength concrete. The BF used in this study reduces and control hydration heat. It can also improve concrete fluidity, while AP increases hydration product and accelerates reaction of BF. SF has micro filler effect and makes pozzolanic reaction. It also fabricates high density internal organization. This developed pre-mixed cement can reduce hydration heat and increase hydration product. It is possible to fabricate high density organization and to secure homogeneity. The mock-up test of ultra high strength concrete showed excellent dispersibility and workability and indicated compressive strength more than 150MPa at 28 days.

• 한국가스학회지
• /
• 제25권4호
• /
• pp.49-56
• /
• 2021

액화석유가스(Liquefied Petroleum Gas)는 Propane(C₃H₈)과 Butane(C₄H₁₀)을 주성분으로 한 가스를 액화한 것으로 구분된다. LPG는 혼합 성분에 따라 품질의 차이가 커 성분 함량을 정확하게 측정하는 것이 중요하다. 이와 같은 물질은 혼합물의 성분별로 상온에서는 액체와 기체가 같이 공존해 정확한 측정이 까다롭다. 따라서 탄화수소의 성분별 농도의 측정 불확도가 높아 실제 함량 기준과 많은 차이가 발생하는 문제점을 안고 있다. 그러므로 탄화수소 물질의 조성과 정확한 농도 측정을 위해 혼합 액체 프로판 표준가스의 개발이 필요하였다. 혼합 액체 프로판 표준가스는 ISO-6142(2015)의 중량법으로 벨로즈형 정압실린더에 제조되었다. 제조한 4병의 표준가스에서 균질성이 GC-FID로 확인되었다. 제조 상대확장불확도는 0.01 % - 0.30 %, 균질성은 0.03 % - 0.25 %이었다. 이 혼합 액체 프로판 표준가스에서 중량법, 제조 일치성, 실린더 흡착 여부 및 장기 안정성에 대한 상대확장불확도는 0.26 % - 1.39 %(신뢰도 약 95 %, k=2)이내로 개발되었다.

• 한국세라믹학회지
• /
• 제30권4호
• /
• pp.265-272
• /
• 1993

Effect of mixing homogeneity in powder mixtures of Si3N4 and sintering additive (10mol% YAG) prepared by coprecipitation on the mechanical properties of pressureless-sintered body was investigated. Sintering was performed in a graphtie furnace at 1850℃ for 0.5h under 0.15MPa N2 atmosphere using Si3N4 powder bed. Results from the measurement of Young's modulus, Vickers hardness, 4-point-bending strength, and KIC for the coprecipitation-treated (CP) and the mechanically-mixed specimens(MM) showed that a remarkable improvement in flexural strength and Weibull parameter can be achieved for the CPspecimens: (677±68MPa, 12.0) for CP samples and (539±108MPa, 5.5) for MM. Other properties were almost same irrespective of preparation methods.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제13권4호
• /
• pp.273-285
• /
• 2013

Because process variations have direct influence on yield rate in process industry, it is very important to understand process variations that occur accidentally. In process industry, quality variation due to the activities of process improvement and maintenance and chance effect such as change of work environment and difference in staffs' craftsmanship are mixed with each other, therefore it is difficult to actually detect minute process variations. In this study, objective and rational methods of detection that can detect minute process variations in process industry were designed referring to various methodologies of process management, and they were verified through similar examples.