• Journal of the Mineralogical Society of Korea
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• v.20 no.4
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• pp.261-266
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• 2007

A natural FeOOH-goethite was compressed up to 9.5 GPa at room temperature using a DIA-type large volume apparatus with synchrotron radiation. Energy dispersive x-ray diffraction method was employed to measure its compressibility and NaCl was used for high pressure determinations. Bulk modulus was determined to be 131.1 (${\pm}5.8$) GPa by the Birch-Murnaghan equation of state with $K_0'$ fixed to 4. The present result is not in accord with the previous measurements, which vary from 111 to 147.9 GPa.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.233-235
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• 2008

본 논문에서는 복잡한 형상을 갖는 여러개의 셀로 구성된 스마트무인기의 각 연료탱크에 대해 높이변화에 대한 체적변화를 분석하여 그 관계를 간단한 다항식으로 표현하였다. 그리고 탱크 셀 수보다 적은 수의 Probe를 이용하여 전체 연료량을 계측할 수 있는 효과적인 방법을 제시하였다. 이러한 결과는 측정 Probe의 계측 프로그램에 활용될 수 있다.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.409-415
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• 2022

Plant growth and development are also affected by root-zone environment. Therefore, it is important to consider the variables of the root-zone environment when establishing an irrigation strategy. The purpose of this study is to analyze the relationship between the volumetric moisture content (VWC), Bulk EC (ECb), and Pore EC (ECp) used by plant roots using FDR sensors in two types of rockwool media with different water transmission characteristics, using the method above this was used to establish a method for collecting and correcting available root-zone environmental data. For the experiment, two types of rockwool medium (RW1, RW2) with different physical characteristics were used. The moisture content (MC) and ECb were measured using an FDR sensor, ECp was measured after extracting the residual nutrient solution from the medium using a disposable syringe in the center of the medium at a volumetric moisture content (VWC) of 10-100%. Then, ECb and ECp are measured by supplying nutrient solution having different concentration (distilled water, 0.5-5.0) to two types of media (RW1, RW2) in each volume water content range (0 to 100%). The relationship between ECb and ECp in RW1 and RW2 media is best suited for cubic polynomial. The relationship between ECb and ECp according to volume moisture content (VWC) range showed a large error rate in the low volume moisture content (VWC) range of 10-60%. The correlation between the sensor measured value (ECb) and the ECp used by plant roots according to the volumetric water content (VWC) range was the most suitable for the Paraboloid equation in both media (RW1, RW2). The coefficient of determination the calibration equation for RW1 and RW2 media were 0.936, 0.947, respectively.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.127-135
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• 2014

Purpose : By taking advantage of each imaging modality, the use of fused CT/MRI image has increased in prostate cancer radiation therapy. However, fusion uncertainty may cause partial target miss or normal organ overdose. In order to complement such limitation, our hospital acquired MRI image (Planning MRI) by setting up patients with the same fixing tool and posture as CT simulation. This study aims to evaluate the usefulness of the Planning MRI through comparing and analyzing the diagnostic MRI image and Planning MRI image. Materials and Methods : This study targeted 10 patients who had been diagnosed with prostate cancer and prescribed nonhormone and definitive RT 70 Gy/28 fx from August 2011 to July 2013. Each patient had both CT and MRI simulations. The MRI images were acquired within one half hour after the CT simulation. The acquired CT/MRI images were fused primarily based on bony structure matching. This study measured the volume of prostate in the images of Planning MRI and diagnostic MRI. The diameters at the craniocaudal, anteroposterior and left-to-right directions from the center of prostate were measured in order to compare changes in the shape of prostate. Results : As a result of comparing the volume of prostate in the images of Planning MRI and diagnostic MRI, they were found to be $25.01cm^3$(range $15.84-34.75cm^3$) and $25.05cm^3$(range $15.28-35.88cm^3$) on average respectively. The diagnostic MRI had an increase of 0.12 % as compared with the Planning MRI. On the planning MRI, there was an increase in the volume by $7.46cm^3$(29 %) at the transition zone directions, and there was a decrease in the volume by $8.52cm^3$(34 %) in the peripheral zone direction. As a result of measuring the diameters at the craniocaudal, anteroposterior and left-to-right directions in the prostate, the Planning MRI was found to have on average 3.82cm, 2.38cm and 4.59cm respectively and the diagnostic MRI was found to have on average 3.37cm, 2.76cm and 4.51cm respectively. All three prostate diameters changed and the change was significant in the Planning MRI. On average, the anteroposterior prostate diameter decrease by 0.38cm(13 %). The mean right-to-left and craniocaudal diameter increased by 0.08cm(1.6 %) and 0.45cm(13 %), respectively. Conclusion : Based on the results of this study, it was found that the total volumes of prostate in the Planning MRI and the diagnostic MRI were not significantly different. However, there was a change in the shape and partial volume of prostate due to the insertion of prostate balloon tube to the rectum. Thus, if the Planning MRI images were used when conducting the fusion of CT/MRI images, it would be possible to include the target in the CTV without a loss as much as the increased volume in the transition zone. Also, it would be possible to reduce the radiation dose delivered to the rectum through separating more clearly the reduction of peripheral zone volume. Therefore, the author of this study believes that acquisition of Planning MRI image should be made to ensure target delineation and localization accuracy.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.167-178
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• 2000

An experimental study on step up filling method is carried out to reinforce the Yano method which is widely used to estimate volume ratio and self-weight consolidation settlement in reclamation area. This method considers actual reclamation construction in which dredged clay is continuously filled and rising of deposit height is presented as a result of volume decrease by height rising and self-weight consolidation. It measured the relationship between filling velocity and deposit rising velocity; calculated the total filling height which is needed to achieve the planned final deposit height, and its solid height and the time which is taken to finish the planned final deposit height; and on the basis of these calculated parameters, predicted the self-weight consolidation and volume change ratio in reclamation construction. Yano method is also used to predict the same conditions. 29.8% in self-weight consolidation, 31.1% in volume ratio, 40% in void ratio and water content is underestimated in Yano method compared to step up filling method.

• The Journal of Engineering Geology
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• v.20 no.3
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• pp.281-295
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• 2010

A new, automated apparatus is proposed for calculating the Soil-Water Characteristic Curve (SWCC), representing a simple and easily applied testing device for continuous measurements of the volumetric water content and suction of unsaturated soils. The use of this apparatus helps to avoid the errors that arise when performing experiments. Consequently, the apparatus provides greater accuracy in calculating the SWCC of unsaturated soils. The apparatus is composed of a pressure panel, flow cell, water reservoir, air bubble trap, balance, sample-preparation accessories, and measurement system, among other components. The air pressure can attain 300 kPa, and a general test can be completed in a short time. The apparatus can simply control the drying process and wetting process. The changes in volumetric water content that occur during the drying and wetting processes are shown directly in the SWRC program, in real time. As a case study, we performed an SWCC test of Joomunjin sand (75% relative density) to measure matric suction and volumetric water content during both the drying and wetting processes. The test revealed hysteresis behavior, whereby the water content on the wetting curve is always lower than that on the drying curve for a specific matric suction, during the wetting and drying processes. Based on the test results, SWCCs were estimated using the Brooks and Corey, van Genuchten, and Fredlund and Xing models. The van Genuchten model performed best for the given soil conditions, as it yielded the highest coefficient of determination.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.267-275
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• 2020

Purpose: In this study, GPR exploration equipment, spray vehicles and flow meters, core drill, borehole image processing system(BIPS), 3D cavity imagery equipment, and cavity formatting equipment were used to identify this cavity growth process. Method: A certain amount of water was injected in proportion to the mass of the cavity, and the cavity was observed to expand as the injected water was drained out. The cavity rating change was evaluated by quantitatively evaluating the expansion factors and the speed of growth. Results: According to the results of examining the volume change through injection time - injection flow rate - volume increase for the four experimenters, the volume increase decreased as the injection time increased, and there was no further increase in volume if injected for one hour or so. Conclusion: In addition, the injection test analyzed the volumetric variation to determine whether the cause of the cavity occurrence was the effect of the underground burial in the vicinity of the cavity. Therefore, it was found that the cavity expansion is caused by the repetition of the relaxation soil collapse due to the groundwater flow and the loss of the collapsed soil below the cavity.

• Radiation Oncology Journal
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• v.24 no.4
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• pp.285-293
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• 2006

$\underline{Purpose}$: This study was to search the optimal slice thickness of computed tomography (CT) in an intensity modulated radiation therapy plan through changing the slice thickness and comparing the change of the calculated absorbed dose with measured absorbed dose. $\underline{Materials\;and\;Methods}$: An intensity modulated radiation therapy plan for a head and neck cancer patient was done, first of all. Then CT with various ranges of slice thickness ($0.125{\sim}1.0\;cm$) for a head and neck anthropomorphic phantom was done and the images were reconstructed. The plan parameters obtained from the plan of the head and neck cancer patient was applied into the reconstructed images of the phantom and then absorbed doses were calculated. Films were inserted into the phantom, and irradiated with 6 MV X-ray with the same beam data obtained from the head and neck cancer patient. Films were then scanned and isodoses were measured with the use of film measurement software and were compared with the calculated isodeses. $\underline{Results}$: As the slice thickness of CT decreased, the volume of the phantom and the maximum absorbed dose increased. As the slice thickness of CT changed from 0.125 to 1.0 cm, the maximum absorbed dose changed ${\sim}5%$. The difference between the measured and calculated volume of the phantom was small ($3.7{\sim}3.8%$) when the slice thickness of CT was 0.25 cm or less. The difference between the measured and calculated dose was small ($0.35{\sim}1.40%$) when the slice thickness of CT was 0.25 cm or less. $\underline{Conclusion}$: Because the difference between the measured and calculated dose in a head and neck phantom was small and the difference between the measured and calculated volume was small when the slice thickness of CT was 0.25 cm or less, we suggest that the slice thickness of CT should be 0.25 cm or less for an optimal intensity modulated radiation therapy plan.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.12
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• pp.1108-1115
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• 2015

In this study, correlation equations were arranged about mass flow rates of oxygen and volume flow rates of helium using a mouthpiece method. The mouthpiece method can reduce examination cost by using similar empirical formula. Instead of liquid oxygen, in the mouthpiece method, gas helium can be measured in order to determine the leakage amount of liquid oxygen conveniently. Experiment was conducted and compared to understand leakage amount relation between the helium and the oxygen for prototype item under a room and a cryogenic temperature conditions. The leakage volume flow rate [$A.m{\ell}/s$] of the helium was 174 times higher than mass flow rate [g/s] of the oxygen leakage at liquid state. The derived correlation equations were verified using data from the National Institute of Standards and Technology (NIST).

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.1434-1438
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• 2004

저수지 수질모형의 기초자료로서의 수체의 수리학적 인자는 물리적인 자료이므로 많은 실측 자료를 필요로 한다. 이러한 자료의 취득을 위하여 수체의 수심을 측정하고, 대상구역의 수계특성을 잘 반영할 수 있도록 수체를 분할하여 각 구간별 수체 중심, 특성길이, 연직 및 수평 단면적, 수표면적, 수체적, 수로경사 등을 구하여 사용한다. 이러한 자료의 취득은 여러 가지 어려움으로 인하여 조사지점이 조밀하지 못하거나 계간방법이 개발되지 못하는 등의 이유로 인하여 실제값과 상당한 차이를 나타내기도 하므로 이를 개선할 수 있는 방법을 제시하고자 한다. 최근에 개발된 다중 음향탐사기 (MBES)는 초음파를 발사하여 하상에서 반사한 파의 시간을 측정하고 거리로 환산하여 수심을 측정하는 것으로 여러 지점의 수심을 동시에 스캔할 수 있다는 장점이 있다. 또한 MBES는 수신기의 지향각이 존재하므로 파의 반사지점을 정확하게 파악할 수 있다. 단일 음향측심기는 측선을 따라 수심을 측정하므로 조사간격이 넓어 정확한 수로정보를 얻기에는 미흡한 점이 있으나 MBES는 수체 전체를 $1\times1m$ 당 $4\~5$ 번의 측정하고, 변화가 심한 호저면에서도 수심오차 $5\~8 cm$의 고분해능을 갖는다. 이를 이용하면 하상의 수심에 내한 3차원의 연속분포를 생성하고, 하상의 지형적인 특징을 조사${\cdot}$ 분석할 수 있으며 하상의 성상과정에 관한 기초자료로도 활용한 수 있다. 수체정보를 산정할 때 단일 음향측심법은 간접적으로 자료를 취득하므로 주관적인 견해 및 큰 오차를 내포하고 있으나, MBES는 Hypack Max를 이용하여 구획한 구간에 따른 수표면적과 연직단면적 및 수체적을 자동으로 계산한다. 그리고 측정한 자료의 raw data를 이용하면 각 구간에 대한 무게중심을 구하여 중점으로 사용 가능하고, 종방향의 구축을 산정하여 수로의 깊이 및 중심간 길이를 정확하게 계산할 수 있다.