• 대한화학회지
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• 제23권4호
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• pp.206-209
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• 1979

Empirical force-field method를 단결정 회절방법으로 구조가 연구된 여덟개의 1,6-anhydropyranose 분자구조$^{13{\sim}21}$에 적용하였다. 이론적 계산에서도 분자들간의 pyranose고리 conformation의 $^1C_4$와 $E_0$ 사이간의 차이는 실험치와 비슷하게 얻어졌다. Five-membered anhydro 고리의 분자들간의 작은 conformation 차이는 잘 예측되지 않았다. C-C결합 길이의 계산치는 실험치와 0.012${\AA}$내에서, C-O결합 길이는 0.027${\AA}$내에서, non-hydrogen atom의 결합각은 1.9$^{\circ}$이내에서 일치되고 있다

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.377-380
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• 2006

Manufacturing process of Ti-6Al-4V alloy billet was investigated with FEM simulation and experimental analysis. Before the breakdown process of Ti-6Al-4V alloy ingot, FEM simulation for the breakdown processes of Ti-6Al-4V alloy ingot was used to calculate the forging load and state variables such as strain, strain rate and temperature. In order to breakdown the ingot structure and make an equiaxed structure billet, two different processes were employed for a VAR/VAR processed Ti-6Al-4V alloy ingot. Firstly, the ingot was cogged in single-phase $\beta$ field at the temperature of $1,100^{\circ}C$. In the process, the coarse and inhomogeneous structure developed by the double melting process was broken down. The second breakdown was performed by upsetting and cogging processes in $\alpha+\beta$ phase field to obtain the microstructure of fine equixed $\alpha$ structure in the matrix of transformed $\beta$. Finally, the mechanical properties of Ti-6Al-4V alloy billet made in this work were compared with those of other billet and ring product.

• KSBB Journal
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• 제27권2호
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• pp.121-126
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• 2012

In order to explore structural features of minoxidil analogs with a view of enhancing lysyl hydroxylase (LH) inhibitory activity, molecular holographic QSAR (HQSAR) and CoMSIA (comparative molecular similarity indices analysis) were performed. The results from the atomic contributions with optimized the HQSAR 6-2 model indicated that, in case of pyrimidine-1-N-oxide substituent, C2 atom of pyrimidine ring and C'3-C'4 bond of 4-piperidinol group showed the highest impact on the inhibitory activity towards LH enzyme. It was also evident from the information of the optimized CoMSIA F5 model that the inhibitory activity mainly depended on the hydrophobic field contribution (36%) and the hydrogen bond (H-bond) field contribution (49.2%) of substrate molecule. Particularly, it is predicted that the functional groups which disfavor H-bond acceptors in large space around the piperidinol group and also the functional groups which favor the H-bond acceptors at C'4 (& C'5) atom in $R_5$ group play a role for increased inhibitory activity. With this in mind, it is likely that a novel candidate having more improved inhibitory activity on hair growth could be designed in the future.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.151-155
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• 2002

This paper presents a micro fluxgate magnetic sensor in printed circuit board (PCB). The fluxgate sensor consists of five PCB stack layers including one layer magnetic core and four layers of excitation and pick-up coils. The center layer as a magnetic core is made of a micro patterned amorphous magnetic ribbon with extremely high DC permeability of ∼100,000 and the core has a rectangular-ring shape. The amorphous magnetic core is easily saturated due to the low coercive field and closed magnetic path for the excitation field. Four outer layers as an excitation and pick-up coils have a planar solenoid structure. The chip size of the fabricated sensing element is 7.3${\times}$5.7m㎡. Excellent linear response over the range of -100${\mu}$T to +100${\mu}$T is obtained with 540V/T sensitivity at excitation square wave of 3V$\_$P-P/ and 360kHz. The very low power consumption of ∼8mW was measured. This magnetic sensing element which measures the lower fields than 50${\mu}$T, is very useful for various applications such as: portable navigation systems, military research, medical research, and space research.

• 한국전기전자재료학회논문지
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• 제15권8호
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• pp.702-707
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• 2002

This paper presents a micro fluxgate sensor in printed circuit board (PCB). The fluxgate sensor consists of five PCB stack layers including one layer magnetic core and four layers of excitation and pick-up coils. The center layer as a magnetic core is made of a micro patterned amorphous magnetic ribbon and the core has a rectangular-ring shape. The amorphous magnetic core is easily saturated due to the low coercive field and closed magnetic path for the excitation field. Four outer layers as an excitation and pick-up coils have a planar solenoid structure. The chip size of the fabricated sensing element is 7.3$\times$5.7$\textrm{mm}^2$. Excellent linear response over the range of -100$\mu$T to +100$\mu$T is obtained with 540V/T sensitivity at excitation square wave of 3 $V_{p-p}$ and 360kHz. The very low power consumption of ~8mW was measured. This magnetic sensing element, which measures the lower fields than 50$\mu$T, is very useful for various applications such as: portable navigation systems, military research, medical research, and space research.h.

• 천문학회보
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• 제37권1호
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• pp.91.2-91.2
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• 2012

Kokubun (1983) reported the local time variation of normalized amplitude of sudden commencement (SC) with a strong day-night asymmetry at geosynchronous orbit with 81 SC events. Further careful inspection of Kokubun's local time distribution reveals that the normalized SC amplitudes in the prenoon sector are larger than those in the postnoon sector. That is, there is a morning-afternoon asymmetry in the normalized SC amplitudes. Until now, however, there are no studies on this SC-associated morning-afternoon asymmetry at geosynchronous orbit. Motivated by this previous observation, we investigate a large data set (422 SC events in total) of geosynchronous SC observations and confirm that the geosynchronous SC amplitudes is larger in the morning sector than in the afternoon sector. This morning-asymmetry is probably caused by the enhancement of partial ring current, which is located in the premidnight sector, due to solar wind dynamic pressure increase. We also examine the latitudinal and seasonal variations of the normalized SC amplitude. We find that the SC-associated geosynchronous magnetic field perturbations are dependent on the magnetic latitude and season of the year. This may be due to the location of the magnetopause and cross-tail currents enhanced during SC interval with respect to geosynchronous spacecraft position.

• Archives of Plastic Surgery
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• 제35권6호
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• pp.759-761
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• 2008

Purpose: Surgery on digit requires a clear, bloodless field and it can be achieved by using a tourniquet. Several type of tourniquet have been used including Penrose drains and sterile glove with hemostat. We present a simple digital tourniquet using nelaton catheter, which is easily available, inexpensive, easy-to-apply, and effective for digital surgery. Methods: We made a small incision on the opposite side of an opening at the tip of nelaton catheter. Then the other tip of nelaton catheter is passed through the incision to form a ring. Nelaton catheter is placed aournd the base of the injured finger, making a tight circle to desired pressure. Results: A simple tourniquet using nelaton catheter effectively achieves a bloodless field and allows fine control of the pressure for digital surgery. Conclusion: We present a sismple digital tourniquet using nelaton catheter, which is easily available, inexpensive, tunable, and available for more than one finger.

• 대한기계학회논문집B
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• 제27권6호
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• pp.773-780
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• 2003

The three-dimensional spatial structures of impeller flow created by a six bladed Rushton turbine have identified based on the volumetric velocity information from multi-plane stereoscopic PIV measurements. A total of 10 planes with 2 mm space and a 50 mm by 64 mm size of the field of view were targeted. To reduce the depth of focus, we adopted an angle offset configuration which satisfied the Scheimpflug condition. The distortion compensation procedure was utilized during the in situ calibration. Phase-locked instantaneous data were ensemble averaged and interpolated in order to obtain mean 3-D. volumetric velocity fields on a 60 degree sector of a cylindrical ring volume enclosing the turbine blade. Using the equi-vorticity surface rendering, the spatial structure of the trailing vortices was clearly demonstrated. Detail flow characteristics of the radial jet reported in previous studies of mixer flows were easily identified.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.286-289
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• 2003

In the case of high voltage devices, junction termination plays an important role in determining the breakdown voltage of the device. The mesa junction termination has been demonstrated to yield nearly ideal breakdown voltage for 6H-SiC p-n junctions. However, such an approach may not be attractive because of the nonplanar surface, which is difficult to passivate. Moreover, In case of 4H-SiC, ideal breakdown voltage could not be achieved using mesa junction termination. For 4H-SiC planar junction termination technique is more useful one rather than mesa junction termination. In this paper, breakdown characteristics of the 4H-SiC device with planar junction termination, such as FLR(Field Limiting Ring), FP(Field Plate) and JTE(Junction Termination Extension), is presented. In the case of the FLR, breakdown voltage of 1800V is obtained. And breakdown voltage of 1000V and 1150V is also obtained for the case of FP and JTE case, respectively.

• 한국지반신소재학회논문집
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• 제13권3호
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• pp.31-38
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• 2014

지오그리드 감쌈 쇄석말뚝 공법은 지오그리드의 인장구속효과로 인해 연약지반에 시공된 쇄석말뚝의 지지력을 증가시켜주는 공법이다. 본 연구에서는 토목섬유 감쌈 쇄석말뚝(GESC)공법의 설계에 적용할 수 있는 토목섬유 인장저항력과 극한지지력을 산정할 수 있는 합리적인 설계법을 제안하였다. 제안된 설계방법의 적적성을 평가하기 위해 부산 경전선 연약지반 시험시공 결과로부터 산출된 GESC의 극한지지력과 설계법에의해 산정된 극한지지력을 비교 검증하였다. 연구결과 GESC 설계법에 의해 산정된 지지력이 현장시험의 지지력 보다 크게 나타나는 것으로 검토되었다.