• 동의생리병리학회지
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• 제23권1호
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• pp.263-268
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• 2009

Pripheral vertigo occurs if there is a problem with the part of the inner ear that controls balance or with the vestibular nerve, which connects the inner ear to the brainstem. Peripheral vertigo is caused by benign paroxysmal positional vertigo(BPPV), Menieres disease, vestibular neuronitis, or labyrinthitis. We diagnosed five patients who have severe vertigo as peripheral vertigo and Dam Hun. We treated them with Banhabaeckchulchunma-tang gagam and acupuncture. After treatment, vertigo and other symptoms -nausea, vomiting, abdominal discomfort had improved. So I report these cases, but more clinical case reports are needed.

• 천문학회보
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• 제40권2호
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• pp.45.3-46
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• 2015

Space weathering agents such as micrometeoroids and solar wind particles continuously age the uppermost regolith of the lunar surface by comminuting as well as darkening and reddening. Among several maturity indices, we investigate median grain size () and optical maturity (OMAT) of the crater rim walls. Crater rim wall is the most immature place among the impact crater features because the vertical mixing process by mass-movement can enhance the gardening of regolith and the supply of immature materials in the deeper layer to the surface. More than 140 simple and complex craters were considered. Both and OMAT values of the inner rim wall initially increase as the crater size increases until ~10-20 km, then decrease. This transition crater size happens to correspond to the transition diameter from simple to complex craters. For larger craters, i.e., complex craters, it is clear that the inner rim wall of the craters formed in recent eras tend to remain fresh and become mature along with time. For the simple crater case, smaller craters are more mature, which is opposite to the case of complex craters. This is thought to be because smaller craters become flattened more quickly, thus have smaller vertical mixing in the regolith due to mass-movement. We will also discuss on the maturity indices of the crater rim walls at high latitudes as a function of the position angle to see the latitude dependence of the space weathering process.

• 한국주거학회논문집
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• 제13권3호
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• pp.61-69
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• 2002

This research is to analyze the spatial organization of a traditional rural community and its characteristics, the case of Hanbam village located in the north of Daegu city. The conclusions of this study are as follows; 1. The difference between private space and public space in the residential area of Hanbam village is obvious, and these two spaces are organically related each other by means of road. These spaces have some spatial characteristics of organization, such as center, hierarchy and sequence. 2. The private space consists of a residence module and a farming area in the settlement, and it is clearly farmed by the firm fence of rocks and by surrounding roads. Fruit-bearing trees such as Pyrus pyrifolia, Cornus officinalis, Diospyros kaki, Juglans sinensis are planted at the boundary. And most of residences are composed of a building, a inner court and farming fields. 3. The public space for the community mainly functions as ‘a meeting place’for residents, and consists of recreational spaces, ceremonial spaces, community facilities, and social facilities. Among these, Jeong-ja(pavilion), Seong-an Soop(forest) and Dae-chong(building for common use) are of great cultural value as important traditional spaces. 4. Two kinds of road are commonly fecund in the village; spontaneously generated one and planned one. This is straight inner streets and access paths to the village, and that is curvilinear alleys which are connected to Dae-chong, the core of village. Also stone walls and climbing plants on them are major elements of village landscape.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1902-1915
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• 2017

This paper presents the evaluation of a three-phase three-level DC-DC converter which achieves the soft switching condition for all switches in the circuit and uses the phase-shift PWM strategy to adjust electric power at the output side. According to the analysis, the operation modes can be categorized into two cases: in the first case, where the phase shift angle is less than 120 degrees and in the second case, where the phase shift angle is more than 120 degrees. The outer switches of the circuit operate under ZVS condition and the inner switches operate under ZVZCS condition. It has been discovered that under ZCS condition of the inner switches, when the blocking capacitors decrease, they make the voltage across the blocking capacitor higher so the current reduce rapidly. A three-phase three-level DC-DC converter has a maximum efficiency of 93.5% when its load is of 5.7 kW. The results from the experiment have been compared to the results obtained by the $MATLAB^{(R)}$ simulator in order to confirm the validity of the proposed converter.

• Nuclear Engineering and Technology
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• 제5권2호
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• pp.115-131
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• 1973

L.S. Pontryagin의 Maximum Principle과 수직방향을 고려하지 않은 2군 화산 방정식을 우라늄농축도 범위에 제한없이 원통형원자로의 최소 임계질량문제에 적용하였다. 핵연료 장전방법에 관한한 최적 원자로는 내심부와 외심부가 최소의 농축도를 갖고 중간영역은 최대의 농축도를 갖는 3-영역식 원자로인 것으로 밝혀졌다. 상기 3-영역식 원자로를 모델로 하여 임계조건을 유도하였으며, 또한 고리원자로를 예로하여 농축도를 여러가지로 변환시키면서 임계조건의 해를 구하는 수치해석을 수행하였다. 그 결과 여러가지 임계조건중 최소의 임계질량을 갖는 경우는 중간영역에서의 최대 농축도가 1.2%이고 내심부와 외심부에서의 농축도가 0.65%일때라는 것이 판명되었다.

• 한국전기전자재료학회논문지
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• 제18권12호
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• pp.1101-1105
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• 2005

We have investigated the optical properties of Erbium (Er)-implanted GaN by photoluminescence (PL). Various doses of Er ion were implanted on GaN epilayers by ion implantation. Visible green emission lines due to inner 4f shell transitions for $Er^{3+}$ were observed from the PL spectrum of Er-implanted GaN. The emission spectrum consists of two narrow green lines at 537 and 558 nm. The green emission lines are identified as $Er^{3+}$ transitions from the $^{5}H_{11/2}$ and $^{4}S_{3/2}$ levels to the $^{4}I_{15/2}$ ground state. The stronger peaks in the case with the dose of $5{\times}10^{14}cm^{-2}$, together with the relatively higher intensity of the $Er^{3+}$ luminescence in the lower doped sample. It implies that some damage remains in the case with the dose of $1{\times}10^{16}cm^{-2}$. The peak positions of emission lines due to inner 4f shell transitions for $Er^{3+}$ do not change with increasing temperature. It indicates that $Er^{3+}$ related emission depends very little on the ambient temperature.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.236-242
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• 2000

NZP velocities were investigated on Ag sheathed multi filamentary Bi-2223 tape and direction type HTS cable. The critical current($I_c$) of Ag sheathed Bi-2223 tape and direction type HTS cable were 12 A, 63 A at 77 K, 0 T. NZP velocities of tape with two condition of DC and AC were almost same at each temperature. In case of DC, the NZP velocities of numerical analysis and experiment were almost same. NZP velocities of direction type HTS cable were 1.9-2.4 cm/sec. The result shows that the total transport current of spiral type HTS cable in $LN_2$ was 475[A], and transport current passed through almost the outer layer (2-layer). Also, AC transport losses in outer layer of HTS cable was proportion to $I^2$ and higher than losses of inner layer. And in case of $I_p=I_c$, calculated numerical loss density was concentrated on the edge of tape and most of loss density in cable was distributed outer layer more than inner layer.

• 대한소아치과학회지
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• 제47권4호
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• pp.463-468
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• 2020

유표피낭종은 구강 내에서 드물게 보이는 양성병소이며 선천적 혹은 후천적으로 발생할 수 있다. 이 병소는 대개 느리게 자라는 낭종으로, 저작이나 발음을 방해 할 정도로 크기가 커지거나 2차 감염이 발생하기 전 까지는 주로 무증상을 보인다. 따라서 진단이 지연되는 경우가 많으며, 신생아나 영유아에서 진단되는 경우는 매우 드문 병소이다. 유표피낭종은 대부분 구강저에서 발생하며 상순에서의 발생은 드물다. 이 증례에서는 29개월 환아의 상순 내측 점막에서 촉진되는 종물을 구강 내 접근법을 이용하여 외과적으로 적출하고, 조직 병리학적으로 유표피 낭종으로 진단하였기에 보고하는 바이다.

• Geomechanics and Engineering
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• 제14권1호
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• pp.19-27
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• 2018

It follows from the basic principles of mechanics of deformable solids relating to the strength, stability and propagation of elastic waves that the Earth's inner core cannot exist in the form of a spherical structure in the assumed thermobaric conditions and calculation values of physico-mechanical parameters. Pressure level reaches a value that is significantly greater than the theoretical limit of medium strength in the model approximations at the surface of the sphere of the inner core. On the other hand, equilibrium state of the sphere is unstable on the geometric forming at much lower loads under the influence of the "dead" surface loads. In case of the action of "follower" loads, the assumed pressure value on the surface of the sphere is comparable with the value of the critical load of "internal" instability. In these cases, due to the instability of the equilibrium state, propagation of homogeneous deformations becomes uneven in the sphere. Moreover, the elastic waves with actual velocity cannot propagate in such conditions in solid medium. Violation of these fundamental conditions of mechanics required in determining the physical and mechanical properties of the medium should be taken into account in the integrated interpretations of seismic and laboratory (experimental) data. In this case, application of the linear theory of elasticity and elastic waves does not ensure the reliability of results on the structure and composition of the Earth's core despite compliance with the required integral conditions on the mass, moment of inertia and natural oscillations of the Earth.

• 한국멀티미디어학회논문지
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• 제23권2호
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• pp.255-261
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• 2020

As the accidents of cargo and passenger carrying ships occur, the stress faced by the vessel users is increasing. The risk factors for accident deterioration in remote marine area are stronger than those in road accidents, and therefore the need for safety control is greatly emphasized. To overcome such issue, a lot of effort has been made in terms of conducting research and development of the passengers and freights location tracking system. However, the inner bulkhead structures are made of aluminum/steel which is a difficult material to transfer location information through. This study aims to measure the receiving rate of LoRaWAN signal inside the aluminum/steel bulkhead structures with variation in reception strength and distance. The test was taken place at platforms with 6T and 8T enclosures to reflect the same conditions found in fishery patrol boats. The receiving rate of through-the-wall communication at 10M distance turned out to be 86% in case of using two 6T enclosures, and 73% in case of using one 8T enclosure. The result showed that the receiving rate was more affected by the thickness rather than the number of enclosures.