• Journal of Korea Foundry Society
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• v.36 no.2
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• pp.60-66
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• 2016

In this study, comparison of corrosion properties of the Mg-1.5Ge-1Zn (GZ21) alloy and Mg-9Al-1Zn (AZ91) alloy were investigated. The studied alloys were fabricated by permanent mold casting method. And the potentiodynamic test, hydrogen evolution test, immersion test and A.C Impedance test were carried out in a 3.5% NaCl solution with pH7.2 at room temperature to measure the corrosion properties. The microstructure of GZ21 alloy was composed of ${\alpha}-Mg$ and $Mg_2Ge$ phases and AZ91 alloy was composed of ${\alpha}-Mg$ and $Mg_{17}Al_{12}$ phases. From the test results, the corrosion property was improved by adding Ge. It seemed that the corrosion mechanism was changed from galvanic corrosion (AZ91) to filiform corrosion (GZ21).

• Journal of the Society of Naval Architects of Korea
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• v.51 no.6
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• pp.539-547
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• 2014

Ship squat is a well known phenomenon, which means an additional sinkage and a change of trim when a ship sails in shallow water. As a series of ship squat study, a HPMM(Horizontal Planar Motion Mechanism) test of KVLCC2 model ship to measure a sinkage and a trim in shallow water was conducted. Additionally a CFD(Computational Fluid Dynamics) analysis was carried out to simulate fluid flows around the ship surface. A change in ship speed, drift angle at three depth conditions(H/T = 1.2, 1.5 & 2.0) is considered for comparing these results. As a result, an increase of the ship speed and the drift angle caused an increase in ship squat in EFD(Experimental Fluid Dynamics), and created a lower pressure on the ship bottom area in CFD. Lastly the sinkage results of KVLCC2 by EFD and CFD are compared to results by three empirical formulas. The tendency of sinkage by EFD and CFD is similar to the results of empirical formulas.

• Journal of the Korean Magnetics Society
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• v.26 no.5
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• pp.173-178
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• 2016

This study is to evaluate the effect of a Contrast Media (CM) on dose calculations and clinical significance in Radiation (Electromagnetic wave) Therapy (RT) plans for head & neck (H&N) and prostate cancer. Pinnacle 8.0 system was used to measure the change of Electron Density (ED) of the tissue for CM. To determine the effect of dose calculation due to CM, we did the RT planning for 30 patients. To compare the ED and dose calculations of RT plans, 3D CRT and IMRT plans were do with pinnacle and Tomotherapy planning system. Mean difference of ED between enhanced and unenhanced CT was less than 4%: H&N Target Volume (TV) 2.1%, parotid 1.9%, SMG 3.6%, tongue 0.9%, spinal cord 0.3%, esophagus 2.6%, mandible 0.1% and prostate TV 0.7%, lymph node 1.1%, bladder 1.2%, rectum 1.5%, small bowel 1.2%, colon 0.6%, penile bulb 0.8%, femoral head -0.2%. The dose difference between RT plan using CM and without CM showed an increase of dose in TV. The rate of increase was less than 2.5% (3D CRT: H&N 0.69~2.51%, prostate 0.04~1.14%, IMRT: H&N 0.58~1.31%, prostate 0.36~1.04%). RT plans using a CM has the insignificant effect on the organs and TV, so this error is allowable clinically. However, the much more accurate plan is possible as to image fusion (CM and without CM images) to ROI contour and when dose calculation, use the without CM image. Using the fusion of 'ROI import' perform calculations on without CM, it will be able to reduce the error (1~3%) caused by the CM.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.3
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• pp.30-37
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• 2001

This study was conducted to investigate physicochemical property changes from July 1998 to August 2001 in Mt. Bukhansan National Park. Four water sampling points were selected to measure the quality of stream water in the northeastern part of the Mt. Bukhansan National Park. The results were summarized as follows; In spring, the average pH of stream water was below the first class of the river water quality standard, while it was normal level in summer. The average electrical conductivity was about 2.3~3.3 times higher in downstream water than in upstream water during spring and summer. The contents of anions($Cl^-$, $NO{_3}^-$, $SO{_4}^{2-}$) were about 1.1~7.4 and 0.4~11.4 times higher in downstream than in upstream water, respectively. These results indicate that water quality was poorer in downstream than in upstream water. We suggest that stream water in the Mt. Bukhansan National Park should be protected from impacts of snow melting mineral particles in spring season and human impacts like wastewater of point source in summer season.

• BMB Reports
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• v.44 no.7
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• pp.458-461
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• 2011

Enteropeptidase is a serine protease secreted by the pancreas and converts inactive trypsinogen to active trypsin. Enteropeptidase cleaves the C-terminal end of the substrate recognition sequence Asp-Asp-Asp-Asp-Lys ($D_4K$). The assay for enteropeptidase has utilized $GD_4K$-conjugated 2-naphthylamine ($GD_4K$-NA) as a fluorogenic probe over the last 30 years. However, no other $D_4K$-conjugated fluorogenic substrates of enteropeptidase have been reported. Furthermore, naphthalene is known as carcinogenic to humans. In this study, we used shift in the emission spectrum of $GD_4K$-conjugated 7-amino-4-methylcoumarin ($GD_4K$-AMC) as a fluorogenic method to measure enteropeptidase activity. The kinetic analysis revealed that enteropeptidase has a $K_M$ of 0.025 mM and a $k_{cat}$ of 65 $sec^{-1}$ for $GD_4K$-AMC, whereas it has a $K_M$ of 0.5 to 0.6 mM and a $k_{cat}$ of 25 $sec^{-1}$ for $GD_4K$-NA. The optimum pH of $GD_4K$-AMC hydrolysis was pH 8.0. Our data indicate that $GD_4K$-AMC is more suitable as a substrate for enteropeptidase than $GD_4K$-NA.

• Korean Journal of Plant Taxonomy
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• v.45 no.1
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• pp.29-35
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• 2015

Sasa borealis (Hack.) Makino & Shibata is widely distributed in South Korea. With amplified fragment length polymorphism (AFLP) markers, we analyzed the genetic diversity of S. borealis to predict and measure the phytogeographical factors of these populations. Relatively high levels of genetic diversity (PPL = 37.2%, h = 0.143, I = 0.205) and genetic differentiation ($G_{ST}$ = 0.324, ${\theta}^B$ = 0.395) were confirmed in populations of S. borealis. Moreover, an analysis of molecular variance (AMOVA) showed that the rate of differentiation among the populations was 47.7%. The results showed that genetic diversity is inversely proportional to the latitude of the S. borealis populations, indicating that the distribution of S. borealis may have extended from lower to higher latitudes. This method of investigating the correlation between genetic diversity and latitude presents critical information for estimating changes in distributions and plant conservation due to climate change.

• Journal of Drive and Control
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• v.20 no.2
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• pp.31-39
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• 2023

The aim of this study was to measure and analyze engine load factor (LF) according to working conditions (operation type and gear stage) of small agricultural multi-purpose cultivator to estimate the emission of air pollutants. To calculate LF, a torque sensor capable of collecting torque and rotational speed was installed on the engine output shaft and DAQ was used to collect data. A field test was conducted with major operation of a cultivator and tillage operations (plow tillage and rotary tillage). Engine power was calculated using engine torque and rotational speed and LF was calculated using real-time power and rated power. In addition, unified LF was calculated using the weight for each operation and the average LF for each operation. As a result, average LF values at 1.87 and 3.10 km/h by plow tillage were 0.50 and 0.69, respectively. Average LF values at 1.87 and 3.10 km/h by rotary tillage were 0.70 and 0.78, respectively. Furthermore, unified LF calculated in consideration of the weight factor showed a value of 0.65, which was 135% higher than the conventional LF (0.48). Results of this study could be used as basic information for realizing LF values in the field of agricultural machinery.

• Journal of Broadcast Engineering
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• v.17 no.6
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• pp.1091-1105
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• 2012

In this paper, we analyzed statistical characteristics and complexity of HEVC encoder as a leading research of acceleration, optimization and parallelization. Computational complexity of the HEVC encoder is approximately twice the compression performance compared to H.264/AVC. But, the increase of encoder complexity remains a problem to be solved in the future. Before performing the research on acceleration, optimization and parallelization to reduce high complexity of HEVC encoder, we measure the complexity each module for HEVC encoder using it's reference software HM 7.1. We also measured the predicted complexity of fast HEVC encoder software, used in real applications, using HM 7.1 applying fast encoding method. The complexity is measured in terms of the operating cycle of the encoder software under the common test sequences and conditions in the Windows PC environment. In addition, we analyze statistical characteristics of HEVC encoder software according to encoding structures and limitation using coded bitstreams.

• Journal of Radiation Protection and Research
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• v.44 no.3
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• pp.97-102
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• 2019

Background: Dose rate meters are the most widely used, and perhaps one of the most important tools for the measurement of ionising radiation. They are often the first, or only, device available to a user for an instant check of radiation dose at a certain location. Throughout the world, radiation safety practices rely strongly on the output of these dose rate meters. But how well do we know the quality of their output? Materials and Methods: This review is based on the measurements 1,158 commercially available dose rate meters of 116 different makes and models. Expected versus the displayed dose patterns and consistency was checked at various dose rates between $5{\mu}Gy{\cdot}h^{-1}$ and $2mGy{\cdot}h^{-1}$. Samples of these meters were then selected for further investigation and were exposed to radiation sources covering photon energies from 50 keV to 1.5 MeV. The effect of detector orientation on its reading was also investigated. Rather than focusing on the angular response distribution that is often reported by the manufacturer of the device, this study focussed on the design ergonomics i.e. the angles that the operator will realistically use to measure a dose rate. Results and Discussion: This review shows the scope and boundaries of the ionising radiation dose rate estimations that are made using commonly available meters. Observations showed both inter and intra make and model variations, occasional cases of instrument failure, instrument walk away, and erroneous response. Conclusion: The results indicate the significance of selecting and maintaining suitable monitors for specific applications in radiation safety.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.2 no.1
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• pp.45-49
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• 2009

This paper proposes a data glove for a rehabilitation robot interface for the upper extremity paralysis. The designed data glove uses seven flexible sensors so as to measure the flexion angles of fingers and wrist. We verified the performance of the data glove using a 3D graphic interface developed. The experimental results show that the proposed data glove is feasible to sense hand motions and applicable to the robot interface.