• 대한치과보철학회지
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• 제25권1호
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• pp.317-325
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• 1987

A study on the shear bonding strength between dental alloy and porcelain according to various kidns of sputtered metallic thin films was established by Ingtron universal testing machine, and the change of the elemental weight % at the surface of dental alloy was studied by E.D.S. The kind of metallic thin films were Al, Ni, In, Cr. Ti and Sn with $0.3{\mu}m$ thickness. The dental alloys were Verabond made by Aalba Dent. Co. and Degudent H manufactured by Degussa Co. The control groups were Verabond and Degudent H. The obtained results were as follows; 1. The shear bonding strength of Al plated sample was the strongest of all. 2. The shear bonding strength of Ni plated sample was stronger than that of Degudent H, Sn plated samples. 3. The shear bonding strength of Verabond was weaker than that of Al, Ni, In, Cr, plated samples. 4. After degassing, it is more weight % of Ni at the alloy surface of the Ni sputtered specimen than the Sn sputtered sample.

• 한국가시화정보학회지
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• 제13권1호
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• pp.35-42
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• 2015

CD4+ T-cell count determines the effectiveness for antiretroviral therapy (ART) in patients with human immunodeficiency virus (HIV). Although ART slows the progression of HIV to AIDS, rapid counting of CD4+ T lymphocytes with a drop of patient's blood sample is urgently needed to ensure timely ART treatment in rural areas. Recently point-of-care CD4 testing devices have been developed by using non-flow based imaging cytometer incorporated with a sample cartridge where CD4+ T cells are reacted with fluorescently tagged specific antibodies. Here we conducted an experimental study using a conventional fluorescence microscope-based imaging system to quantitate the interaction of CD4 antibodies with CD4+ T cells at different reaction conditions. We demonstrated that a fast and affordable point-of-care CD4 test is feasible with a far less amount of antibodies and a shorter incubation time compared with a conventional sample preparation protocol for flow cytometry. We also proposed a general method to evaluate and compare the detection limit across different CD4 counting platforms by using fluorescently labelled microbeads for intensity calibration.

• 대한안전경영과학회지
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• 제8권5호
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• pp.17-25
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• 2006

Nowadays most colleges are confronting with a serious problem because many students have left their majors at the colleges. In order to make a countermeasure for reducing major separation rate, many universities are trying to find a proper solution. As a similar endeavor, the objective of this paper Is to find a predicting model of students leaving their majors. The sample for this study was chosen from a university in Kangwon-Do during seven years(2000.3.1 $\sim$ 2006. 6.30). In this study, the ratio of training sample versus testing sample among partition data was controlled as 50% : 50% for a validation test of data division. Also, this study provides values about accuracy, sensitivity, specificity about three kinds of algorithms including CHAID, CART and C4.5. In addition, ROC chart and gains chart were used for classification of students leaving their majors. The analysis results were very informative since those enable us to know the most important factors such as semester taking a course, grade on cultural subjects, scholarship, grade on majors, and total completion of courses which can affect students leaving their majors.

• 한국지반공학회논문집
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• 제15권3호
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• pp.177-197
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• 1999

암석의 탄성파속도를 측정하는 방법은 암석의 공학적 특성을 나타내는 하나의 지표로서 일반적으로 인식되고 있어서 우리나라에서도 $\lower right quadrant건설\; 표준품셈\upper left quadrant$등의 암판정 기준으로서 보편적으로 사용되고 있다. 그러나 암석의 탄성파속도는 시료의 함수상태에 따라서 크게 변화하는 사실을 충분히 인식하지 못하고 있으므로 본 논문은 한국화강암에서 관찰된 변화특성을 설명한다. 국제 암반역학회에서 추천하고 있는 암석의 탄성파속도 측정방법도 역시 실험상의 어려움이 있는데, 예를 들면 암석시료의 양쪽 끝에서 탄성파가 잘 측정되도록 하기 위하여 사용되는 바셀린이 암석 시료내로 침투하는 경우가 하나의 문제점이고, 또한 암석시료가 함수됨에 따라서 시료의 체적이 팽창하는 경우에도 해석상의 어려움이 있다. 또한 서서히 함수정도를 증가시키는 경우에 암석시료내에서 탄성파속도의 변화를 관찰하여 보면 암석시료내에 존재하는 잔류응력을 파악하는 한 방법으로서도 사용될 수도 있다는 것을 알 수 있다.

• 천문학회보
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• 제45권1호
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• pp.68.3-69
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• 2020

We develop a series of N-body data challenges, functional to the final analysis of the extended Baryon Oscillation Spectroscopic Survey (eBOSS) Data Release 16 (DR16) galaxy sample, primarily based on high-fidelity catalogs constructed from the Outer Rim simulation. We generate synthetic galaxy mocks by populating Outer Rim halos with a variety of halo occupation distribution (HOD) schemes of increasing complexity, spanning different redshift intervals. We then assess the performance of three complementary redshift space distortion (RSD) models in configuration and Fourier space, adopted for the analysis of the complete DR16 eBOSS sample of Luminous Red Galaxies (LRGs). We find that all the methods are mutually consistent, with comparable systematic errors on the Alcock-Paczynski parameters and the growth of structure, and robust to different HOD prescriptions - thus validating the robustness of the models and the pipelines used for the baryon acoustic oscillation (BAO) and full shape clustering analysis. Our study is relevant for the final eBOSS DR16 'consensus cosmology', as the systematic error budget is informed by testing the results of analyses against these high-resolution mocks. In addition, it is also useful for future large-volume surveys, since similar mock-making techniques and systematic corrections can be readily extended to model for instance the DESI galaxy sample.

• 방사성폐기물학회지
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• 제22권1호
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• pp.67-80
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• 2024

Fundamental aspects of creating passivation layers for corrosion resistance in nuclear engineering applications, specifically the ability to form complete layers versus porous ones, are being explored in this study. Utilizing a laser ablation technique, 1,064 nm fire at 10 Hz with 60 pulses per shot and 0.5 mm between impact points, aluminum samples are treated in an attempt to create a fully formed passivation layer that will be tested in a LiCl-KCl eutectic salt. By placing these samples into an electrochemical environment mimicking a pyroprocessing system, corrosion rates, resistances and material characteristics are tested for one week and then compared between treated and untreated samples. In initial testing, linear sweep voltammetry indicates corrosion current density for the untreated sample at -0.038 mA·cm^-2 and treated samples at -0.024 mA·cm^-2 and -0.016 mA·cm^-2, respectively. This correlates to a control sample corrosion rate of -0.205 mm·yr^-1 and treated rates of -0.130 mm·yr^-1 and -0.086 mm·yr^-1 for samples 1 and 2. In addition, electrochemical impedance spectroscopy circuits show application of a longer-lasting porous passivation layer on the treated metal, compared to the naturally forming layer. However, the current technique fails to create a uniform protection layer across the sample.

• Journal of the Korean Statistical Society
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• 제22권2호
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• pp.325-337
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• 1993

This paper propose two test statistics which enable us to proceed the variable selection in Fisher's linear discriminant function for the case of heterogeneous discrimination with equal training sample size. Simultaneous confidence intervals associated with the test are also given. These are exact and approximate results. The latter is based upon an approximation of a linear sum of Wishart distributions with unequal scale matrices. Using simulated sampling experiments, powers of the two tests have been tabulated, and power comparisons have been made between them.

• International Journal of Reliability and Applications
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• 제1권2호
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• pp.133-143
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• 2000

Data from weighted distributions appear, among other situations, when some of the data are missing or are damaged, a case that is important in reliability and life testing. The kernel method for hazard rate estimation is discussed for these data where the basic large sample properties are given. As a by product, the basic properties of the kernel estimate of the distribution function for data from weighted distribution are presented.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 가을 학술발표회 논문집
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• pp.345-350
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• 1999

In this study the results of investigation on the physical and mechanical properties of a rockfill dam body were provided. On the crest of the old Namgang dam to be excavated partially, various in-situ tests(boring with SPT, sampling of undisturbed sample, field density test, field permeability test) and geophysical investigation works were performed Rock materials, i.e., shale and sandstone, were collected, and their slake durability was evaluated using slaking durability testing method which is suggested by ISRM.

• 품질경영학회지
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• 제17권2호
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• pp.70-80
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• 1989

A nonparametric test for testing the parallelism of regression lines against ordered alternatives is proposed. The proposed test statistic is based on a linear combination of robust slope estimators. It is a modified version of the Adichie's test statistics based on scores. A snail-sample Monte Carlo study shows that the proposed test is compatible with the Adichie's test.