• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2797-2802
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• 2014

Nucleophilic substitution reactions of Y-aryl methyl (8) and Y-aryl propyl (10) chlorothiophosphates with substituted anilines and deuterated anilines are investigated kinetically in acetonitrile at $55.0^{\circ}C$. A concerted mechanism is proposed for 8 based on the negative ${\rho}_{XY}$ (= -0.23) value, while a stepwise mechanism with a rate-limiting leaving group departure from the intermediate is proposed for 10 based on the positive ${\rho}_{XY}$ (= +0.68) value. The deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) are 0.89-1.28 and 0.62-1.20 with 8 and 10, respectively. Primary normal and secondary inverse DKIEs are rationalized by a frontside attack involving hydrogen bonded, four-center-type transition state and backside attack involving in-line-type transition state, respectively.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1829-1834
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• 2013

The nucleophilic substitution reactions of Y-aryl ethyl isothiocyanophosphates with substituted X-anilines and deuterated X-anilines were investigated kinetically in acetonitrile at $75.0^{\circ}C$. The free energy relationships with X in the nucleophiles exhibited biphasic concave downwards with a break point at X = H. A stepwise mechanism with rate-limiting bond formation for strongly basic anilines and with rate-limiting bond breaking for weakly basic anilines is proposed based on the negative and positive ${\rho}_{XY}$ values, respectively. The deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) changed gradually from primary normal with strongly basic anilines, via primary normal and secondary inverse with aniline, to secondary inverse with weakly basic anilines. The primary normal and secondary inverse DKIEs were rationalized by frontside attack involving hydrogen bonded, four-center-type TSf and backside attack involving in-line-type TSb, respectively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.79-82
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• 2005

The hybrid rocket has been known for over 50 years. It is safe and cheap but wasn't widely used for the deficit of low regression rate. However, the hybrid rocket propulsion system will replace a lot of fields of missiles, rockets and propulsion systems of launch vehicles with new development of paraffin based solid fuel composition

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.703-706
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• 2004

This paper deals with the various sealing conditions in a vacuum and the discharge characteristics. The MgO thin film is prepared by e-beam evaporation method. Sealing process was performed in a vacuum at panel temperature of 430 $^{\circ}C$. We find the cracks on the MgO film surface, which results in higher discharge voltage and lower luminous efficiency. The vacuum in-line sealing technology does not require additional annealing process but induces the MgO cracks because of the high temperature sealing cycle in a vacuum. Therefore we modify the vacuum in-line sealing cycle which the MgO cracks are not found and the good characteristics of plasma displays are found in higher sealing pressure at sealing temperature of 430 $^{\circ}C$.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.533-535
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• 2004

We suggest the use of a self-assembled ultra thin organic film that can suppress the hydration of MgO protective layer in AC-PDP. We analyzed the degree of hydration of MgO layer in AC-PDP by XPS when exposed to air after vacuum deposition which proved the effectiveness of the hydration prevention. We also made PDP test panels to demonstrate the improvement in the luminance and luminous efficiency when the hydration of MgO surface is suppressed by the use of self-assembled ultra thin organic film.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.561-563
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• 2004

In this paper, distortion of waveform in AC-PDP module has been studied. The propagation losses and interference due to coupling between the electrodes can be considered as the causes for waveform distortion. The distorted waveform has been obtained from the calculated propagation losses. The coupling between the electrodes has been measured using a proper experimental setup. This distorted waveform could account for underfiring problem in AC PDP module.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.529-531
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• 2004

For localization, it is very important for an autonomous mobile robot to be able to recognize indoor environment and match an object it detect to an object within a map developed either online or offline. Given the map defining the locations of geometric beacons like wall and comer existing in the robot operation environment, this paper presents a stereo ultrasonic sensor based method that can be conveniently used in recognizing the geometric beacons. The stereo ultrasonic sensor used in the experiment consists of an ultrasonic transmitter and two ultrasonic receivers placed symmetrically about the transmitter. Experiment shows that the proposed method is more efficient in recognizing wall and coner than the conventional method of using multiple number of transmitter-receiver pairs.

• Microbiology and Biotechnology Letters
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• v.24 no.3
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• pp.321-326
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• 1996

In the course of screening for new bioactive compounds from oligotrophs in soil, a microorganism, designated as SA-246 and now identified as Micromonospora sp., has been shown to produce a strong antibacterial compound. The active compound was purified from broth filtrate by ethylacetate extraction, silica gel column chromatography, preparative TLC and HPLC, and was identified as crisamicin A based on mass and NMR spectral data. The compound SA- 246 exhibited not only strong antibacterial activity against Gram-positive bacteria but also cytotoxicity against cancer cell lines such as A549 (lung), SK-OV-3 (ovarian), SK-MEL-2 (melanoma), XF498 (central nervous system) and HCT15 (colon).

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.839-842
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• 2008

본 연구는 LCD 패널에서 시청모드별 사용자의 피로도 차이에 대한 연구이다 LCD 사용에 따른 사용자 피로도에 미치는 영향이 보고되고 있는 것을 감안하여 감성 공학적 방법을 이용하여 시청모드에 따른 사용자 피로도 차이를 분석하였다. 실험은 34명의 대학생을 두 그룹으로 나누어서 같은 동영상 조건에서 각각 영화모드와 표준모드를 60분간 시청하게 하였다. 시청 시의 피로도를 알아보기 위해 생리신호 반응(GSR, PPG, SKT), 눈 움직임(동공의 확대 축소속도, 눈 깜박임률) 및 주관적 피로도(긴장도, 쾌적도, 피로도)를 측정하였다. 그 결과 주관적인 평가와 생리 반응에서 영화모드가 표준모드보다 더 피로감을 유발시키는 것을 확인 할 수 있었다. 눈 움직임 반응에서는 통계적으로 유의한 결과를 얻지 못하였다.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2003.10a
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• pp.181-181
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• 2003