• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.4
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• pp.491-496
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• 2017

The hydrogen($H_2$) is promising energy carrier of renewable energy in the microgrid system such as small village and military base due to its high energy density, pure emission and convenient transportation. $H_2$ can be generated by photocatalytic water splitting, gasification of biomass and water electrolysis driven by solar cell or wind turbine. Solid oxide electrolysis cells(SOECs) are the most efficient way to mass production due to high operating temperature improving the electrode kinetics and reducing the electrolyte resistance. The SOECs are consist of nickel-yttria stabilized zirconia(NiO-YSZ) fuel electrode / YSZ electrolyte / lanthanum strontium manganite-YSZ(LSM-YSZ) air electrode due to similarity to Solid Oxide Fuel Cells(SOFCs). The Ni-YSZ most widely used fuel electrode shows several problems at SOEC mode such as degradation of the fuel electrode because of Ni particle's redox reaction and agglomeration. Therefore Ni-YSZ need to be replaced to an alternative fuel electrode material. In this study, We studied on the Double perovskite $PrBrMnO_{5+{\delta}}$(PBMO) due to its high electric conductivity, catalytic activity and electrochemical stability. PBMO was impregnated into the scaffold electrolyte $La_{0.8}Sr_{0.2}Ga_{0.85}Mg_{0.15}O_{3-{\delta}}$(LSGM) to be synthesized at low temperature for avoiding secondary phase generated when it exposed to high temperature. The Half cell test was conducted at SOECs and SOFCs modes.

• Animal Systematics, Evolution and Diversity
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• v.9 no.1
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• pp.25-34
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• 1993

Several osteological characters of 45 species belonging to 26 genera and 4 subfamilies in th family Gobiidae were surveyed based on 348 specimens collected from April, 1984 to September, 1992 in the southern part of Korea. The characters include the following: first dorsal-fin pterygiophore formula, vertebral number, epural number, and number of anal-fin pterygiophores anterior to the first haemal spine. The first dorsal-fin pterygiophore formula and epural number showed considerable stability at the generic level, and the apeared useful characters at the species level. Among them, the epural number used formerly to distinguish gobiid subfamilies was considered to be unimpotant taxonomic character in the classification of the subfamily Gobiinae.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1067-1072
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• 2012

Recently, linear motors have been widely researched and have been increasingly used in various industrial applications. Especially, permanent magnet linear synchronous motors(PMLSMs) have been getting the spotlight in the transportation system. A PMLSM is structurally simple and has a lot of merits such as high speed, high thrust force, etc. However, in case of a long stator system which arranges armature to the full length of transportation lines, a PMLSM has some disadvantages such as the material cost increase and long manufacturing time. Hence, in order to overcome these problems, the PMLSM with stationary discontinuous armature structure and concentrated windings was proposed. However, this method occurs undesirable cogging force by outlet edge effect. The cogging force causes thrust force ripples and generates noise and vibration. Therefore, in this paper, we proposed installation method of auxiliary pole PMLSM with concentrated winding applying bifurcating in order to reduce cogging force by the outlet edge when the armature is placed in a discontinuous arrangement. Also, we have examined characteristics of outlet edge cogging force using 2-D finite element analysis(FEA).

• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.570-575
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• 2005

In this study, we have manufactured electrodeless ultraviolet lamp which has a long life and a high degree of efficiency than the existing electrode UV lamp used in sewage effluent sterilization disinfection. First, we investigated change of UV intensity and temperature of lamp by activation materials. The best results for the dose response experiments were 250 minutes stabilizing to UV intensity of $300{\mu}W/cm^2$ and surface temperature $200{\sim}250^{\circ}C$ in Hg/Ind's weight ratio 95/5. When electrodeless UV lamp emits light for prolonged hours, surface temperature of lamp increases. therefore, temperature change is studied using a duplex lamp for cooling in actual sewerage process. Also, manufactured electrodeless UV lamp showed sterilization efficiency of more than 99.9% as result that experiment manufactured electrodeless UV lamp by E-coli. for sterilization disinfection of sewage effluent.

• Journal of Korea Water Resources Association
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• v.35 no.3
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• pp.295-306
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• 2002

The modified TOPMODEL of two storage systems has been integrated to the generalized assumptions of decreasing hydraulic conductivity to vertical direction. Three different recharge functions were introduced to explore the impact of the macropore flow to vortical direction, the storage at the surface zone and the relative storage deficit of the soil matrix. Combinations of these approaches provide 30 type of the model structure for the hillslope hydrology. Developed models have been applied to several hydrologic events at the Sulmachun watershed. The performance evaluation with the Monte carlo simulation suggests that the exponential function of transmissivity reduction should be appropriate form for the physically -based hydrologic simulation on the Sulmachun watershed. It has been shown that the recharge function of macropore flow contributes to improve the predictability of the generalized version of modified TOPMODEL.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.1
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• pp.83-88
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• 2008

Thromboembolic disease associated with assisted reproductive techniques is considered to be extremely rare but most serious complication. The reasons for this are thought to hypercoagulable state characteristic of OHSS due to high serum levels of estrogen, hemoconcentration and reduced circulating blood volume, but is still unclear. The risk is increased those with rare hypercoagulable conditions such as antiphospholipid antibody syndrome, protein C deficiency, protein S deficiency, antithrombin III deficiency, and those with a personal or family history of thromboembolic disease. The majority of thrombosis reported were venous site but arterial thrombosis mostly intracerebral was reported 5 cases in Korea so far. We present a case of basilar a. thrombosis at 11 days after hCG injection. The patient developed the right hemiparesis, and recovered after intraarterial thrombolysis and transluminal angioplasty. Protein S activity was decreased and vWF antigen was increased. Decreased protein S activity was also found in previous reported 4 cases, so we suggest screening test for protein S in OHSS patients.

• Economic and Environmental Geology
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• v.40 no.2 s.183
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• pp.191-207
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• 2007

A paleomagnetic investigation for the Cretaceous rocks in the Buyeo and Hampyeong Basins, located out of the Gyeongsang Basin, was carried out in order to elucidate the paleomagnetic directions in conjunction with the formation of the basins. Typical stepwise thermal demagnetization and measurement methods were used to determine the directions of characteristic remanent magnetizations (ChRMs). The mean direction of the sedimentary rocks from the Buyeo Basin after bedding correction $(D/I=356.5^{\circ}/61.5^{\circ},\;k=39.3\;\alpha_{95}=7.4^{\circ})$, is more dispersed than that before bedding correction $(D/I=356.5^{\circ}/61.5^{\circ},\;k=39.3\;\alpha_{95}=7.4^{\circ})$, which suggests that the rocks in the Buyeo Basin were remagnetized. However, the statistics and dispersion of the ChRM directions after bedding correction are still acceptable and the paleomagnetic pole position after tilt correction $(Lat./Long.=69.3^{\circ}N/186.7^{\circ}E,\;K=11.6\;A_{95}=14.0^{\circ})$ is closer to that of the Late Cretaceous pole of the Korean Peninsula. More detailed study is needed to confirm the nature of the remagnetization in the Buyeo Basin. On the other hand, the paleomagnetic pole before bedding correction $(Lat./Long.=81.6^{\circ}N/106.9^{\circ}E,\;K=25.1\;A_{95}=9.3^{\circ})$ is positioned near the paleogene pole of the Eurasian APWP. The mean ChRM direction of the sedimentary rocks from the Hampyeong Basin after bedding correction is $D/I=32.5^{\circ}/55.4^{\circ},\;(k=35.6,\;\alpha_{95}=8.7^{\circ})$. It is more clustered than that before bedding correction $D/I=18.3^{\circ}/62.5^{\circ},\;k=14.1,\;\alpha_{95}=14.2^{\circ})$, indicating that the ChRM was acquired before tilting of the strata. The paleomagnetic pole position of the Cretaceous sedimentary rocks in the Hampyeong Basin, averaged out of site pole positions calculated from the tilt-corrected ChRMs, is $Lat./Long.=63.9^{\circ}N/202.7^{\circ}E,\;(K=21.3,\;A_{95}=7.6^{\circ})$, similar to the Late Cretaceous paleomagnetic pole of the Korean Peninsula $(Lat./Long.=70.9^{\circ}N/215.4^{\circ}E,\;A_{95}=5.3^{\circ})$, suggesting that the Hampyeong Basin has been stable since the Late Cretaceous period. One normal and two reversed ChRM directions are revealed through the measurements of the volcanic rocks from the Hampyeong Basin. Although these normal and reversed directions are not exactly antipodal, it is interpreted that the normal direction is the representative primary direction of the volcanic rocks of the Hampyeong Basin and the mixed polarity is the records of geomagnetic field at the time of the formation of the volcanic rocks. Paleomagnetic poles are at $Lat./Long.=70.2^{\circ}N/199.5^{\circ}E,\;(K=18.1,\;A_{95}=9.6^{\circ})$ for the normal direction, and $Lat./Long.=65.5^{\circ}S/251.3^{\circ}E,\;(K=7.1,\;A_{95}=20.7^{\circ})$ for the reversed direction. Compared with the representative pole positions of the Cretaceous period of the Korean Peninsula, it is concluded that the age of the volcanic rocks in the Hampyeong Basin is of the Late Cretaceous.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1658-1662
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• 2009

최근 들어 기후 변화로 인한 이상 강우 현상과 기록적인 집중 강우로 탁수 발생의 빈도와 강도가 증가하고, 탁수의 장기간 하류 방류로 인해 경제적인 피해가 발생할 뿐만 아니라 환경적으로도 중요한 문제로 대두되고 있다. 저수지로 유입된 탁수의 시공간적 분포 예측 결과의 신뢰도는 탁수 밀도류 해석의 정확도에 가장 큰 영향을 받으므로 유입 하천수의 밀도 거동에 대한 정확한 해석이 필요하다. 따라서 탁수의 거동해석은 수리 및 수질의 연동 모의(Coupled modeling)가 필수적이다. 본 연구의 목적은 수리 및 수질의 연동 해석이 가능한 2차원 횡 방향 평균 모형(CE-QUAL-W2)을 소양호에 구축하고, 기록적인 강우 사상을 보인 2006년 수문조건에서의 모형의 적용성과 한계점을 평가하는데 있다. 구축한 소양호 탁수 예측 모델을 2006년 탁수사상에 적용한 결과, 홍수 사상으로 이중 첨두 유량이 발생한 후 저수지 내에서 중층 밀도류와 바닥밀도류의 두 가지 밀도류 형태가 혼재하여 진행되는 현상이 적절히 모의되었다. 하지만, 저수지내에서 측정한 탁수 수괴(plume)의 시공간적 수직분포(profiles)는 모의결과와 다소 편차를 보였으며, 특히 저수지 바닥 인근에서 모델은 실측값을 과대평가 하였다. 오차의 원인은 모델 입력 자료의 불확실성과 수치모델의 불확실성으로 판단된다. 따라서 향후 탁수 거동 모델링과정의 불확실성을 최소화하고 모의결과의 신뢰도를 개선하기 위해서 극한탁수 사상에서 발생하는 수리학적 현상과 SS 입자 동력학에 대한 이론적 연구와 입력 자료의 정확한 산정을 위한 현장 실험이 필요하다.

• Journal of the Korean Magnetics Society
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• v.23 no.2
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• pp.77-81
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• 2013

The objective of this study is experimentally to investigate natural convective heat transfer characteristics of the ferrofluid for a concentric annuli under rotating magnetic field with variations of the revolution and the magnetic field strength. The rotating magnetic field was provided by induction motor with 6 poles and 3 phases and the revolution and the magnetic field strength were controlled by an inverter driver and a voltage meter, respectively. Temperatures of the inner pipe and the outer pipe in the tested concentric annuli were maintained at $30^{\circ}C$ and $25^{\circ}C$, respectively, during the test and the direction of the rotating magnetic field was a counterclockwise. As a result, the natural convective heat transfer characteristics of the ferrofluid for a concentric annuli were increased with the rise of the revolution and magnetic field strength due to the increased heat dissipation between hot side and cold side of the concentric annuli.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.750_751
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• 2009

This paper deals with the PM performance evaluations in a pole changing memory motor (PCMM) using a coupled transient finite element method (FEM) and Preisach modeling, which is presented to analyze the magnetic characteristics of permanent magnets. The focus of this paper is the dynamic characteristics evaluation relative to magnetizing direction and the pole number of machine on redemagnetization condition in a pole changing memory motor