• Journal of the Semiconductor & Display Technology
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• v.2 no.4
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• pp.23-26
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• 2003

The general users find difficulties in using ellipsometers. Thus, the object of this study is to construct an ellipsometer with simple operation principle. We developed an ellipsometer which does not require alignment and calibration before measuring sample. A basis structure model after rotating a compensator spectroscopic ellipsometry, the fixed incidence angle at $70^{\circ}$. This ellipsometer does not demand calibration, because the plane of incidence is not changed due to the novel sample holder structure. The results for various standard samples were compared with those from conventional RCSE to test the performance of this instrument. Also repeated measurements were performed to test the precision of the calibration coefficient in a plane of incidence fixed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.3057-3065
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• 1994

An experimental study has been made for heat transfer and particle deposition during the Modified Chemical Vapor Deposition process which is currently utilized to manufacture high quality optical waveguides. The distributions of tube wall temperatures, rates and efficiencies of particle deposition were measured. Results indicate that the temperature distributions of the tube wall in the axial direction yield the quasi-steady form in which temperature distributions fit in one curve if the relative distance from the moving torch is used as an axial coordinate. Due to the repeated heatings from the traversing torch, the wall temperatures are shown to reach the minimum ahead of torch and it is shown that the two torch formulation suggested by Park and Choi is valid to predict this minimum temperature. Measured wall temperatures, particle deposition efficiencies and tapered entry length are compared with the previous modelling results and shown to be in agreement.

• Fashion & Textile Research Journal
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• v.1 no.1
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• pp.50-55
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• 1999

The repeatability of fabric drape was studied. Two methods for draping were used and the relation between node distributions was investigated using statistical analysis. With this, the relationship between node distribution and fabric mechanical properties was studied. The repeated measurements showed that there was no evidence that fabric has intrinsic node number and the mechanical properties influence on the number of nodes.

• Proceedings of the Korean Magnestics Society Conference
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• 2005.12a
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• pp.80-81
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• 2005

The resilience of the exchange bias ($H_{EX}$) in ferromagnet / antiferromagnet bilayers is generally studied in terms of repeated hysteresis loop cycling or by protracted annealing under reversed field (training and long-term relaxation respectively). The stability of $H_{EX}$ is fundamental for practical application of exchange bias systems. In this paper we report measurements of training and relaxation in FeNi films coupled with the antiferromagnet FeMn. We show that $H_{EX}$ suppressed both by training and relaxation was partially recovered as soon as a field cycling for consecutive hysteresis loop measurement was stopped or the magnetization of the ferromagnet was switched back to the biased direction.

• Journal of Biosystems Engineering
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• v.30 no.5 s.112
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• pp.312-317
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• 2005

A flow injection type biosensor was tested to confirm the performance of a batch and a continuous type flow injection unit. Reproducibility and consistence of the biosensor were investigated to determine the effect of pulsations and air bubbles, and the applicability of on-line monitoring. The air bubbles affected the performance of the sensor irrespective of the location, and also the pulsations of the pump influenced the performance of the sensor. The applicability of on-line motoring was accepted as the result of the repeated and long-term measurements.

• Communications for Statistical Applications and Methods
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• v.23 no.6
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• pp.575-585
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• 2016

Longitudinal studies repeatedly measure outcomes over time. Therefore, repeated measurements are serially correlated from same subject (within-subject variation) and there is also variation between subjects (between-subject variation). The serial correlation and the between-subject variation must be taken into account to make proper inference on covariate effects (Diggle et al., 2002). However, estimation of the covariance matrix is challenging because of many parameters and positive definiteness of the matrix. To overcome these limitations, we propose autoregressive moving average Cholesky decomposition (ARMACD) for the linear mixed models. The ARMACD allows a class of flexible, nonstationary, and heteroscedastic models that exploits the structure allowed by combining the AR and MA modeling of the random effects covariance matrix. We analyze a real dataset to illustrate our proposed methods.

• Journal of Integrative Natural Science
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• v.14 no.4
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• pp.155-158
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• 2021

To study the effects of hormones and neurotransmitters, zebrafish (Danio rerio) are a great substitute for water fleas (Daphnia). The zebrafish is an ideal vertebrate model because it has a transparent embryonic stage. It is easy to get consistent heart rate measurements in embryonic zebrafish when treating them with hormones and neurotransmitters. To observe the heart rate, two to three embryonic zebrafish are anesthetized with MS-222 and then transferred to a glass slide specifically designed for heart observation and easy application of various chemicals. After the heartbeats are counted for 2 minutes, apply either 100 µM epinephrine or 100 µM acetylcholine to the zebrafish. Wait 5, 10, and 20 minutes and count the heartbeats at each time point. All procedures are repeated three times. The final results are averaged and analyzed by using statistical methods. The above method which we have developed is practical enough for high school students to measure the heart rate in zebrafish under various conditions and to analyze the data set.

• Journal of the Korea Society of Computer and Information
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• v.24 no.2
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• pp.157-161
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• 2019

In this paper, the researcher investigated whether strengthening the back muscles affects the quality of chest compressions during cardiopulmonary resuscitation by university students. A total of 50 students majoring in healthcare were included from September 2018 to November. The participants performed chest compressions during cardiopulmonary resuscitation (CPR) for 2 min after back muscle strength was measured. Then, after adequate rest, the participants repeated the back muscle strength measurements and chest compressions after taping the erector spinae muscle. The paired t-test was performed to analyze changes in chest compression quality after taping. As results, taping enhanced back muscle strength and positively affected the depth of chest compressions and the compression to recoil ratio. Taping also increased confidence and lowered fatigability during chest compressions, so the participants preferred being taped while performing chest compressions. Based on these results, taping could help emergency room medical personnel specialized in CPR to enhance the quality of CPR and relieve back pain and fatigability by strengthening the back muscles.

• Geomechanics and Engineering
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• v.17 no.6
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• pp.597-606
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• 2019

Ultrasonic Time-of-Flight Diffraction (TOFD) techniques are useful methods for non-destructive evaluation of fracture characteristics. This study focuses on the reliability and accuracy of ultrasonic diffraction methods to estimate the depth of rock fractures. The study material includes three different rock types; andesite, basalt and ignimbrite. Four different ultrasonic techniques were performed on these intact rocks. Artificial near-surface fracture depths were created in the laboratory by sawing. The reliability and accuracy of each technique was assessed by comparison of the repeated measurements at different path lengths along the rock surface. The standard error associated with the predictive equations is very small and their reliability and accuracy seem to be high enough to be utilized in estimating the depth of rock fractures. The performances of these techniques were re-evaluated after filling the artificial fractures with another material to simulate natural infills.

• Bulletin of the Korean Chemical Society
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• v.9 no.4
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• pp.248-251
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• 1988

Mechanism of electrochemical polymerization of pyrrole (Py) on a Pt electrode in acidic aqueous solutions was studied by means of potentiostatic measurements, cyclic voltammetry and chronopotentiometry. Pyrrole molecule appeared to be initially oxidized via two-electron transfer step to produce oxidized pyrrole ion ($Py^+$), which was coupled with a non-oxidized pyrrole to yield a dimerized species, Py-Py. The Py-Py thus formed was further oxidized again via two-electron transfer step, which was followed by coupling with non-oxidized monomer and by concomitant expulsion of a $H^+$. Then the latter chain extension process was repeated. The chain extension and polypyrrole oxidation reactions occurred competitively.