• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1151-1158
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• 2020

In order to investigate the speed profile of data I/O of HDD, we have developed an utility program. The application to HDD reveals the detail properties of the speed profile of HDD and the relation between the cylinder structure of HDD and the velocity profile. For the extent application, the experiment of the large volume storage was performed, and the profile of SSD media, which is known as the new rapid media, was measured. The new M.2 NVME SSD, which has the ability of over 10Gbps, we can compare the velocities between cp under linux O/S and the utility, and shows that the performance of the utility can be reliable.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.11
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• pp.45-51
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• 1995

In order to suggest the proper cutting conditons of the CNC milling machining for the free-form surface, some experments were carried out. In the experiments, the influence of cutting conditions on a inclined spherical surface were examined by geometrical analysis. In this study, the roundness and cutting force were measured to know the effect of several cutting conditions on the machined surface and the cutting characteristics were carefully investigated. The results obtained in this study are aw follows. 1) If the tool ha s enough rigidity, we can get better dimensional accuracy in up-ward cutting than down- ward cutting. 2) A great roundness error is appeared on the surface declined under 30 degress to the horizontal plane in circular machining by a bal end mill. 3) If the thrust force is increased, the stability of tool is decreased. And the phenomenon is apperared in great in down-ward cutting than up-ward cutting.

• Journal of the Daesoon Academy of Sciences
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• v.23
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• pp.37-105
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• 2014

'공사(公事)'는 『전경』이 담고 있는 매우 중요한 종교 문화적 현상이다. 그리고 그 속에는 매우 깊은 사상적 의미가 내포되어 있다. 대순진리회 공사개념의 연원은 중국 고대의 경전과 문헌에서 그 단서를 찾아볼 수 있으나, 그것은 결코 단순히 중국의 것을 답습한 것이 아니다. 강성상제와 도주 조정산께서는 '묵은 하늘'의 음양 혼란 시대에 공사를 행하였기 때문에, 도수를 바로잡는 공사는 근본부터 바로잡는다는 의미가 있으며, 새로운 시대를 의미하는 '개벽'도 이에 포함된다. 중도, 화평, 공정은 질서가 바로 잡힌 사회의 시작을 의미하며, 이는 새로운 생활을 창조하는 데 있어 중요한 현실적 의의를 지닌다. 전체적으로 볼 때 대순진리회의 공사는 사회의 변화와 사회적 요구에 응답하여 생겨난 종교문화 활동이다. 이러한 종교문화 활동은 일종의 기호로서, 상징성을 갖춘 의식을 거행하는 것이다. 공사는 명부의 한을 해결하는 것으로부터 시작되는데, 이는 근본을 중시한다는 의미이며, 태초로 거슬러 올라가 사회를 다스리는 커다란 방향을 전개한다는 것이다. '역도(逆度)'를 조정하는 공사에서는 사회적 관점에서 보자면, 역사가 남긴 문제에 대해 고민하고 해결하려는 태도를 뜻한다. 이는 민생문제를 매우 중시하였음과 인간의 도에 대해 경외심과 존중을 표현하고 있음이 나타내며, 결국 '보세(普世)'의 의미를 지닌다고 볼 수 있다. 공사를 실천하는 방법은 '신생활법'이며, 이는 인(仁)과 인류와 동물에 대한 자비심을 강조하며 '삼계개벽'의 개혁정신과 창조적 사고를 나타낸다. 이로써 '통달(通達)'과 '대도(大道)'의 정신을 나타내었다. 이로 볼 때, 인간의 삶을 인도하며, 궁극적으로는 지상천국을 건설하고자 하는 정신이 공사의 개념 속에 분명하게 드러나 있음을 알 수 있다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.4
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• pp.279-283
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• 2009

Approximately 12,547 kL of oil from the tanker 'Hebei Spirit' released into the western sea of Korea, which subsequently reached and covered extensive areas of the western coastlines of Korea. In the following days great numbers of tar balls hit the southwestern coast. Three different cleanup methods were used to mediate the southwestern coastline tar ball pollution by Korea Coast Guard (KCG) net setting, manual pick up, and sweeping them up. Net setting was useful in protecting coastlines from being hit by tar balls. The cold weather in winter conditions helped the tar ball response efforts because it caused them to harden, allowing them to be swept up from beaches and to be gathered up by hand.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.197-206
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• 2002

The purpose of this study was to investigate the putter head movement during the putting strokes. Highly skilled 5 golfers(less than 3 handicaps) and 5 novice golfers(having no golf experience) participated in this study. A target distance was 3 m. Movements of the putter head were recorded at 60 Hz with two video cameras. The results showed that the novice golfers moved the club significantly longer than the expert golfers(p<.0001). Accoring to a movement time, novice golfers moved their club significantly faster than the expert golfers(p<0.001). Novice golfers could not control the club head effectively, and could not hit the ball correctly. Based on the impact zone movement, sweet spot of novice golfers moved faster(along the line of putt), higher(along the vertical line), and wider(along the side to side line) than that of expert golfers.

• Journal of the Mineralogical Society of Korea
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• v.21 no.2
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• pp.129-138
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• 2008

The characteristics of beneficiating kaolin mineral by liberation (selective grinding) and air classification have been investigated, comparing the grinding rates of ball mill and impact mill. The ore was ground using a ball mill and a impact mill to evaluate the grindability of the two grinding methods based on the constant production amount of fine particles in size less than 325 mesh. Then, the fine product was further separated into two fractions using an air-classifier and each fraction was chemically analyzed to compare the beneficiation efficiency of the two grinding methods. The chemical grade of kaolin mineral decreased as increasing the grinding rate of both the mills. particularly in the case of ball mill because of overgrinding impurities such as quartz and feldspar. In the case of the ball milling, the fine fraction less than 325 mesh was air-classified at a cutting point of $43\;{\mu}m$. The production rate of the air-classified concentrate was found to be 66.2 wt%, removing 5.3% of $Fe_2O_3$ and 34.6% of CaO. Under the same conditions mentioned above with the impact mill, the production rate of the air-classified concentrate was 64.4 wt%, removing 34.2% of $Fe_2O_3$, 67.6% of CaO and 25.0% of $TiO_2$. Therefore, our results indicate that impact mill is superior to ball mill in terms of impurity removal.

• Journal of the Korean Institute of Gas
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• v.22 no.2
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• pp.72-77
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• 2018

This paper presents the FEM analysis results on the strength safety of LPG fuelling nozzle, which is composed of ball valve and long cylinder tube. For the strength safety analysis of LPG fuelling Nozzle, the gas pressure of 0.5~3.5MPa has been supplied to the ball valve and long cylinder tube bodies with the wall thickness of 1.7~3.5mm. The maximum von Mises stress of the ball valve with 1.7mm wall thickness is 25.4MPa for the supply gas pressure of 3.5MPa, which is 25.9% compared with that of the yield stress of the brass. And the maximum von Mises stress was 23.7MPa when a 3.5MPa gas pressure was applied to a long cylinder tube with a wall thickness of 1.7mm, which was 6.7% more safe than the ball valve which was analyzed under the same conditions. For the increased wall thickness, 2.0mm of the long cylinder tube, the maximum von Mises stress of 20.2MPa is 14.8% more safe compared with that of 1.7mm wall thickness of the same cylinder tube. Thus, the wall thickness of the ball valve and cylinder tube is recommended as an optimized thickness of 1.7~2.0mm for the strength safety of the LPG fuelling nozzle.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.115-124
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• 2008

The purpose of this study was to know influenced on the change of Oswestry back pain disability index(OBPDI), isometric muscle power(IMP), muscular activation with chronic low back pain(CLBP) patients after Trunk Stabilization Exercise. Intervention was provided 6 weeks(5 days a week). Muscular activation was measured during IMP(Muscles : transversus abdominis : TA, internal obliqus : IO, external obliqus : EO, rectus abdominis : RA and erector spinae: ES). The results were as follows. 1. OBPDI about the MBE and the SE groups had effective decrease pain and disability. 2. IMP of intervention after the MBE and the SE groups had effective improve muscle power. 3. Muscle activation during IMP of intervention after was : TA, IO, RA had increase in the MBE and the SE groups. EO muscle activation during IMP of intervention after had increase only MBE groups. This shows that the MBE and the SE groups had effective increase because it has effective improve muscle power. Therefore, this study shows ￡hat trunk stabilization exercise program influenced on the change of OBPDI, IMP, muscular activation with CLBP patients.

• Journal of the Korean Ceramic Society
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• v.41 no.5
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• pp.375-380
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• 2004

Pb(Ni$\_$1/3/Nb$\_$2/3/)O$_3$-PbZrO$_3$-PbTiO$_3$ thick films were screen-printed on platinized alumina substrates and fired at 800-1000$^{\circ}C$. Two kinds of powders with different particle size were prepared by attrition and ball milling methods. Effects of particle size of starting material on the microstructure and electrical properties of the thick films were investigated. Average particle size of attrition milled-powder (0.44 ${\mu}$m) was much smaller than that of ball milled-powder (2.87 ${\mu}$m). Average grain size of the thick film prepared from attrition-milled powder was smaller than that of the thick film prepared from ball-milled powder at the sintering temperature of 800$^{\circ}C$. However, the difference in average particle size became smaller with increasing the sintering temperature. Thick films prepared from attrition-milled powders showed more uniform and denser microstructures at all firing temperatures. Thick films prepared from attrition-milled powders had better electrical properties at the firing temperature above 900$^{\circ}C$ than thick films prepared from ball-milled powders. Dielectric constant, remanent polarization and coercive field of the thick film prepared from attrition-milled powders and fired at 900$^{\circ}C$ were 559, 16.3 ${\mu}$C/cm$^2$, and 51.3 kV/cm, respectively.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.2
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• pp.62-67
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• 2011

Launching tube is a kind of case to protect the guided weapons from external environments and conducted as a guide when they are fired. The guided weapons have been firmly kept at the launching tube and transferred, and would be separated at the required time when they are fired To meet the aim, it has been used explosive bolts which are reliable and efficient mechanical fastening devices having the special feature of a built-in release. The disadvantage of explosive bolt lies in that it is based on the high explosive effect of a pyrotechnic charge. When the explosive bolt is ignited, there are some bad effects; a flame, fragments and pyro-shock. Because of these bad effects there are many restriction to use bolt as joining devices to precision guided weapons. To solve these problems, the aim of the present work is to invent the ball-type separation bolt which is a pyrotechnically releasable mechanical linking device for two mechanical elements that does not suffer from such drawbacks. A standard pressure cartridge can moreover be easily integrated inside the device according to the present work and this with no modification to its structure. The present work was represented quantitatively the margin of separation safety and analysed separation mechanism in ball type separating bolt to perform the dynamic separation test.