• Proceedings of the Korean Magnestics Society Conference
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• 2004.06a
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• pp.206-207
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• 2004

수직자기이방성을 갖는 [Co/Pt]$\times$5 다층박막을 상온에서 이온빔 증착(ion beam deposition)법으로 제작하여 자기적 및 열적 특성을 연구하였다. 수직자기이방성 특성은 비정상 홀(Hall)-전압법으로 측정하였으며, 표면광 Kerr 효과로 확인하였다. $[Co(10{\AA}/Pt(12.5{\AA})]{\times}5$) 다층박막에서 수직자성 보자력은 400 Oe이었고 수평자성은 매우 큰 곤란축(hard-axis) 특성을 유지하였다. 진공 열처리 시 1 kOe의 균일한 자기장이 박막면 수평(시료 A)과 수직(시료 B)이 되도록 각각 인가함에 따라 열적안정성을 관찰하였다. 시료 A의 수직자성의 보자력이이 $300^{\circ}C$에서 1 KOe로 유지되어 시료 B의 열적안정성 보다 훨씬 우수하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.650-652
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• 2011

Condition of random distribution of residual dispersion per span (RDPS) for transmission of 40 Gbps optical signal with good performance through optical transmission links with dispersion management (DM) of random RDPS distribution and optical phase conjugator (OPC) is induced in this paper.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.208-211
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• 2000

We prepared Co-Cr-Ta and Co-Cr-Ta/Ti thin film for perpendicular magnetic recording media by facing targets sputtering system (FTS system). Ti underlayer effects on crystallographic and magnetic characteristics of Co-Cr-Ta perpendicular magnetic recording media have been investigated. Crystallgraphic and magnetic characteristic of prepared thin films were evaluated by x-ray diffractometry(XRD), vibrating sample magnetometer(VSM) and kerr hysteresis loop measurement. The coercivity and anisotropy field increase by introduced Ti underlayer when substrate temperature is higher than 150$^{\circ}C$. The c-axis dispersion angle and grain size of Co-Cr-Ta/Ti thin film is decrease than Co-Cr-Ta when substrate temperature is higher than 100$^{\circ}C$. Consequently, the use of a Ti underlayer highly orientated can be improved crystallographic and magnetic characteristics of Co-Cr -Ta perpendicular media layer.

• Electronics and Telecommunications Trends
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• v.34 no.5
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• pp.91-98
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• 2019

Optical frequency comb generators have been investigated as a signal source capable of generating highly stabilized ultrafast pulse lasers. The precise control of the optical frequency comb spacing by RF clock signals has led to a revolutionary paradigm shift in the precise measurement of time and frequency. Optical frequency combs also have advantages such as stable frequency spacing, stable number of lines, and robustness. Owing to these characteristics, optical frequency combs have been applied to the fields of high precision optical clock, communication, spectroscopy, waveform generation, and astronomy. In this article, we introduce the properties (i.e., generation methods, advantages, and so on) of various optical frequency combs, and discuss the expected future technological trends and applications.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.723-725
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• 2013

The compensation characteristics are investigated as a function of the position an optical phase conjugation (OPC) in the optical transmission links with a randomly distributed residual dispersion per span (RDPS). The simulation results show that the optimal net residual dispersion (NRD) is decided to be 10 ps/nm and -10 ps/nm by precompensation and postcompensation, respectively, which are independence of the OPC positions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.370-373
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• 2003

Superluminescent diodes(SLDs) are the optimum light sources for application in optical measurement systems such as fiber gyroscopes, optical time domain reflectometers, and to short and medium distance optical communication systems. The broadband characteristics of SLDs reduce Rayleigh backscattering noise, polarization noise, and the bias offset due to the nonlinear Kerr effect in fiber gyro systems. In this paper, in order to suppress lasing oscillation, we introduced a laterally tilted SCH(Separate Confinement Heterostructure)-SLD with a window region. An output power of 11mW has been achieved at 200mA injection current at 25$^{\circ}C$. At 120mA, parallel and perpendicular to the junction were 31$^{\circ}$${\times}$38$^{\circ}$.

• Journal of the Korean Magnetics Society
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• v.14 no.3
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• pp.105-108
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• 2004

Array of magnetic Ni nanostructures has been fabricated on Si substrate by using nanoporous alumina film as a mask during deposition. The nanostructures are truncated cone-shape and the lateral sizes are comparable to height. While the continuous film shows well-defined in-plane magnetization, the nanostructure shows perpendicular component of magnetization at remanence. The hysterectic behavior of nanostructures is dominated by the demagnetizing field instead of interaction among them.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.975-977
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• 2013

The optimal distribution pattern is induced in the optical link with an artificial distributions of single mode fiber (SMF) lengths and residual dispersion per span (RDPS). It is confirmed that the descending distribution of SMF length and ascending distribution of RDPS are most suitable to compensate for the distorted WDM signals, as the fiber span number is more increased. in the optical link with 10 ps/nm or -10 ps/nm the optimal net residual dispersion (NRD).

• Korean Journal of Culture and Social Issue
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• v.19 no.2
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• pp.159-178
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• 2013

The purpose of this study was to 1) replicate the Wells effect(i.e., reluctance to rule against the Defendant solely on the basis of probabilistic evidence) in Korea and 2) examine the validity of an Alternative explanation(i.e., perception of risk of wrong verdict). In study 1(n=46), mock jurors in the tire-tracks condition were reluctant to rule against the defendant based on their perceived probability and this pattern was not resulted in the tire-tracks-belief condition. Therefore, the Wells effect was replicated in Korea. In study 2(n=70), we manipulated the participants' perception of risk of wrong verdict. That is, participants who were assigned in the high risk perception of wrong verdict were informed that if the defendant were found guilty, the defendant would get considerable demage both in finance and reputation of the company. Participants in the low risk perception of wrong verdict condition were informed that these demage would not be great. The results revealed that the Wells effect was pronounced in the high risk perception of wrong verdict condition. That is, participants were more reluctant to rule against the defendant when they perceive the significance of the result of wrong verdict as high. Limitations of the study and the directions for future study were discussed.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.2
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• pp.119-126
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• 2012

State of problem: Cement-retained implant-supported prostheses are routinely used in dentistry. The use of high strength cements has become more popular with the increasing confidence in the stability of the implant-abutment screw connection and the high survival rates of osseointegrated implants. No clinical data on retention of metal copings using CAD/CAM. To evaluate retention of metal copings using CAD/CAM system bonded to short titanium abutment with four different cements and compare retentive strength of metal copings with sandblasting or without sandblasting before cementation. Forty titanium abutment blocks were fabricated and divided into 4 groups of 10 samples each. Forty metal copings with occlusal hole to allow for retention testing were fabricated using CAD/CAM technology. The four cements were Fujicem(Fuji, Japan), Maxcem Elite(Kerr, USA), Panavia F2.0(Kurarary, Japan) and Superbond C&B(Sunmedical, Japan). The copings were cemented on the titanium abutment according to manufacture's recommendation. All samples were stored for 24h at 37oC in 100% humidity and tested for retention using universal testing machine(Instron) at a crosshead speed of 1.0mm/min. Force at retentive failure was recorded in Newton. The mode of failure was also recorded. Means and standard deviations of loads at failure were analyzed using ANOVA and Paired t-test. Statistical significance was set at P<0.05. Panavia F2.0 provided significantly higher retentive strength than Fujicem, Maxcem Elite(P<0.05). Sandblasting significantly increased bond strength(P<0.05). The mode of failure was cement remaining principally on metal copings. Within the limitation of this study, Panavia F2.0 showed significantly stronger retentive strength than Fujicem, Maxcem Elite(p<0.05). The Ranking order of the cements to retain the copings was Panavia F2.0, Fujicem = Maxcem Elite. Sandblasting significantly increased bond strength(P<0.05). The retentive strength of metal copings on implant abutment were influenced by surface roughness and type of cements.