• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.949-959
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• 2021

The current study aims to explore the shielding properties of multi-component borate-based glass series. Seven glass-samples with composition of (80-y)H₃BO₃-10ZnO-10Na₂O-yBaO where (y = 0, 5, 10, 15, 20, 25 and 30 mol.%) were synthesized by melt-quench method. Various shielding features for photons, neutrons, and protons were determined for all prepared samples. XCOM, Phy-X program, and SRIM code were performed to determine and explain several shielding properties such as equivalent atomic number, exposure build-up factor, specific gamma-ray constants, effective removal cross-section (Σ_R), neutron scattering and absorption, Mass Stopping Power (MSP) and projected range. The energy ranges for photons and protons were 0.015-15 MeV and 0.01-10 MeV, respectively. The mass attenuation coefficient (μ/ρ) was also determined experimentally by utilizing two radioactive sources (¹⁶⁶Ho and ¹³⁷Cs). Consistent results were obtained between experimental and XCOM values in determining μ/ρ of the new glasses. The addition of BaO to the glass matrix led to enhance the μ/ρ and specific gamma-ray constants of glasses. Whereas the remarkable reductions in Σ_R, MSP, and projected range values were reported with increasing BaO concentrations. The acquired results nominate the use of these glasses in different radiation shielding purposes.

• Journal of Korean Vacuum Science & Technology
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• v.6 no.1
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• pp.8-11
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• 2002

Ni, Si and $SiO_2$ films were implanted by 350 keV B $i_{+}$ ions at room temperature with fluences of 1$\times$10$^{16}$ and 2$\times$10$^{16}$ ions/c $m^2$ The depth distributions of implanted B $i^{+}$ ions in Ni, Si and $SiO_2$ films were by investigated by Rutherford backscattering. The results show that the depth distributions of implanted B $i^{+}$ ions into Ni, Si and $SiO_2$ films have obeyed nearly Gaussian distributions. The maximum difference between experimental and calculated values is less than 18 % for mean projected range. Experimental range straggling deviated significantly from calculated value. The possible reasons are discussed.sed.d.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.480-485
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• 2002

The purpose of this paper is the development of guidance algorithm for a mobile robot which is used to acquire the position and state information of the pipe defects such as crack, damage and through hole. The data used for the algorithm is the range data obtained by the range sensor which is based on an optical triangulation method. The sensor, which consists of a laser slit beam and a CCD camera, measures the 3D profile of the pipe's inner surface. After setting the range sensor on the robot, the robot is put into a pipe. While the camera and the LSB sensor part is rotated about the robot axis, a laser slit beam (LSB) is projected onto the inner surface of the pipe and a CCD camera captures the image. From the images the range data is obtained with respect to the sensor coordinate through a series of image processing and applying the sensor matrix. After the data is transformed into the robot coordinate, the position and orientation of the robot should be obtained in order to guide the robot. In addition, analyzing the data, 3D shape of the pipe is constructed and the numerical data for the defects of the pipe can be found. These data will be used for pipe maintenance and service.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.643-644
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• 2006

The purpose of this study is to experimentally analyze swing motion with soft golf clubs and compare with that with normal golf clubs. Soft golf is newly devised recreational sport based on golf but focus on the playability for the elderly. The subject fur the experiment performed swing motion using a normal golf club and a soft golf club in turn. The swing motion of the subjects was tracked using an opto-electric three-dimensional motion analysis system. The results were compared against those obtained with a normal golf club. The range of motion was analyzed along with top head speed for two cases. It was found that higher club head speed could be achieved with reduced range of motion at lumbar joint using soft golf club when compared against the swing using regular club. The lower range of motion fur lumbar bending means reduced risk of injury at the joint. So, it is projected that we can reduce the risk of injury with soft golf while maintaining the club head speed.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1246-1249
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• 1994

Thin amorphous film of $a-Se_{75}Ge_{25}$ acts as a positive resist in ion beam lithography. Previously, we reported the optical characteristics of amorphous $Se_{75}Ge_{25}$ thin film by the low-energy ion beam exposure and presented analytically calculated values such as ion range, ion concentration and ion transmission coefficient, etc. As the calculated results of analytical calculation, the energy loss per unit distance by $Ga^+$ ion is about $10^3[keV/{\mu}m]$ and nearly constant for all energy range. Especially, the projected range and struggling for 80 [KeV] $Ga^+$ ion energy are 0.0425[${\mu}m$] and 0.020[${\mu}m$], respectively. Hear, we present the results of Monte-Carlo computer simulation of Ga ion scattering, exposure and development in $a-Se_{75}Ge_{25}$ resist film for focused ion beam(FIB) lithography. Monte-Carlo method is based on the simulation of individual particles through their successive collisions with resist atoms. By the summation of the scattering events occurring in a large number N(N>10000) of simulated trajectories within the resist, the distribution for the range parameters is obtained. Also, the deposited energy density and the development pattern by a Gaussian or a rectangular ion beam exposure can be obtained.

• Journal of Biosystems Engineering
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• v.19 no.1
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• pp.9-16
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• 1994

135 and 136 pine cones were sampled from age class of II to VI Korean pine trees for the study of their physical properties in 1991 and 1992, respectively. The length, width, weight, volume, and the largest projected area of cones were measured, and the specific gravity, apparent volume ratio sphericity, and roundness were calculated. Regression analysis were performed for the weight, volume, and projected area to the cone length and width. The length, and major and minor diameters of the cone stalks were measured and analyzed. 1. The range of the length of cone stalks was 0 to 47.3mm. The average length of stalks were 9mm ('91) and 10mm('92), respectively. Cross section of the stalks was ellipse with average major and minor diameters of 9.1mm and 10.1mm, and 8.6 and 8.7mm in 91 and 92, respectively. 2. The length of pine cones distributed from 8cm to 17cm and the average length were about 13cm('91, '92). The width varied from 5cm to 9.5cm and the average width were 6.7cm('91) and 6.9cm('92). The ratios of the length to the width were 0.56('91) and 0.65('91) and the shape of the cones were found to be ellipse with minor diameter of 1/2 to 2/3 of the major diameter. 3. The roundnesses and sphericity of cones were 0.74 and 0.75('91), 0.63 and 0.67('92), respectively. The average of the largest projected area of cones were $85.3cm^2$('91) and $93.1cm^2$('92) and the criterion areas were $71.0cm^2$ and $74.5cm^2$, respectively. 4. Cone weights were from 83g to 467g('91 and '92) and averages were 186g('91) and 220g('92). The average specific gravities were 0.89 and 0.96('91 and '92). The true volumes were $212cm^2$('91) and $230cm^2$('92), and the average bulk volume was $321cm^2$('91, '92). The average apparent volume ratios of cones were 35% ('91) and 28% ('92), respectively. 5. The weight and the volume were proportional to the length of the cone multiplied by the width squred and the largest projected area was proportional to the length multiplied by the width of cones.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.3
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• pp.241-247
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• 2012

The national geodetic reference frame of Korea switched to the International Terrestrial Reference Frame (ITRF) in 2003. In order to study the land area changes, we calculated the entire land area of Korea using the administrative boundaries of census data provided by Statistics Korea. The standard transformation procedure by the National Geographic Information Institute (NGII) was followed. The Transverse Mercator (TM) projected coordinates were transformed into the GRS80-based world geodetic reference frame, and the ellipsoidal and the projected areas were calculated. The provinces that range over two projection origins were divided into two polygons and projected using appropriate origins. After the transformation, all boundaries were shifted in the northwestern direction, resulting in a decreased area of $1.36km^2$ (about 0.0013%) on the projected plane. Moving the boundaries into a high latitude area cancels out the effect of the enlarged ellipsoid. In addition, the rate of change shows that a higher-latitude province is more sensitive to the shift of the boundaries. The data by Statistics Korea is significantly different from those of the Ministry of Land, Transport and Maritime Affairs (MLTM), thus it is urgently recommended that the data are integrated and unified.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.61-71
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• 2006

The purpose of this study was to compare kinematic characteristics on the limbs at 3 different walking speed during the energy and the normal walking. Eight subjects performed energy walking and normal walking at the slow speed(65 beats/min), the normal speed(115beats/min), the fast speed(160 beats/min). The 3-d angle was calculated by vector projected with least squares solution with three-dimensional cinematography(Motion Analysis corporation). The range of motion was calculated on the trunk, shoulder, elbow, hip, knee joint. The results showed that stride length was no difference of the two walking pattern. The duration of support phase was also no difference of the two walking pattern. The range of motion of shoulder joint significantly increased in the sagittal and frontal planes, and the range of motion of elbow joint significantly increased as the energy walking. The range of motion of hip joint had no significant difference in the any planes in changing of walking speed. But the most remarkable difference of the two walking patterns revealed at the trunk. The range of flexion/extension angle had significant increasing $2.36^{\circ}$ at normal speed, and the range of the right/left flexion angle had significant increasing below $4^{\circ}$ at the 3 walking speed, and The range of rotation angle had significant increasing $7.35^{\circ}$, $9.22^{\circ}$, respectively at the normal and slow speed. But there was no significant difference of range of motion at the hip and knee joints between energy walking and normal walking.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.3
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• pp.313-319
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• 2019

As vessels become larger and competition between ports intensifies, there has been an increase in the number of cases where vessels that exceed the available berths are berthed at the pier. Therefore, there has been an increase in the number of cases in which the bow or stern of a ship is projected and moored. The risk of overhanging berthing is that mooring safety can be compromised because it is not possible to connect the bow and stern mooring line to the ship properly. In addition, collision accidents may occur between moving vessels if the view of a vessel moving in the port is obstructed. Therefore, in this study, the simulation of mooring safety was performed according to the overhanging range in Piers No. 6 and 7 in Ulsan's main port to propose the overhanging limit and operational standards according to each ship. As a result of the assessment, 30,000 DWT bulkers are able to overhang up to 0.75B, and 50,000 DWT bulkers can overhang up to 0.50B. The results of this study are expected to be used as basic data for setting the allowable overhang limit, as well as clear usage criteria for safe unloading operations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.5
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• pp.1143-1148
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• 2014

This paper has analyzed the change of subthreshold swing for doping distribution function of asymmetric double gate(DG) MOSFET. The basic factors to determine the characteristics of DGMOSFET are dimensions of channel, i.e. channel length and channel thickness, and doping distribution function. The doping distributions are determined by ion implantation used for channel doping, and follow Gaussian distribution function. Gaussian function has been used as carrier distribution in solving the Poisson's equation. Since the Gaussian function is exactly not symmetric for top and bottome gates, the subthreshold swings are greatly changed for channel length and thickness, and the voltages of top and bottom gates for asymmetric double gate MOSFET. The deviation of subthreshold swings has been investigated for parameters of Gaussian distribution function such as projected range and standard projected deviation in this paper. As a result, we know the subthreshold swing is greatly changed for doping profiles and bias voltage.