• 한국전기전자재료학회논문지
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• 제27권8호
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• pp.510-515
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• 2014

Thin films of cubic $Na_{0.6}WO_3$, which is one of the sodium tungsten bronze, were fabricated by rf sputtering for the electrode applications in integrated sensors and actuators. A single-phase cubic $Na_{0.6}WO_3$ sputtering target of power type was prepared by conventional solid-state reaction. Thin films were deposited from the powder target, and the as-deposited films were amorphous, thus they annealed by tube furnace or RTP for crystallization. Thin films having cubic phase $Na_xWO_3$ were fabricated by the optimization of sputtering and post-annealing conditions, but single-phase cubic $Na_{0.6}WO_3$ thin films were not obtained. Although the films were not in single phase, they had good electrical conduction properties showing electrical resistivities of $10-4{\Omega}{\cdot}cm$ order.

• 한국운동역학회지
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• 제15권2호
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• pp.1-10
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• 2005

G. B. LEE, A. S. GWON, The Research for Using methodof GRF (Ground Reaction Force) on Rotational Movement in Arabesque. Korean Journal of Sport Biomechanics, Vol. 15, No. 2, pp.1-10, 2005. As, in relation to all movements of a human being, the movements such as mutually walking, running, rotating, and jumping are attained endlessly through the ground amid the interaction with the ground, in terms of the harmonious movement of the upper limbs and the lower limbs, related to the basic movement in ballet, the type of a movement depends on the size and direction of the force that presses down the ground (Fz, Fx, Fy) amid the interaction with the ground. Therefore, aiming to correctly and efficiently perform a rotational movement in Arabesque, this study analyzed factors of the force manifestation through GRF (Ground Reaction Force), by dividing into preparing, stepping, standing, rotating, and finishing stages (events (1) ${\sim}$ (5)), targeting the subjects of 4 elite female students who majored in ballet. 1. At the No.5 position of the preparing stage, It is necessary that support the ground with left and right foot balance, 2. As the stepping stage is the phase ranging from the event (2), in which a plie movement of bending a knee is started, to the event (3) of stretching a knee, Rebunding motion is not good, and One have a position with ankle and knee flextion condition in order to stretch strengthly in event (3) position 3. At the event (1) position, It is necessary that exert the Fz reaction force at the event (3) position. Because large stretch force help to have a toe on position easily and show a active motion 4. In order to have a stand and rotation motion smoothly, One need a muscle strength training for ankle extension, knee extension, control horizental force

• 공업화학
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• 제23권6호
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• pp.572-576
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• 2012

온실가스인 $CO_2$를 저감하기 위해 Pt계 촉매상 $CO_2$ methanation 반응에 관한 연구를 수행하였다. $Al_2O_3$의 전구체인 AlO(OH)를 열처리하여 지지체로 사용하였으며, 활성금속으로서 Pt를 사용하였다. XRD 분석결과, 활성금속인 Pt가 고르게 잘 분산되었음이 관찰되었으며, 지지체는 gamma phase의 $Al_2O_3$로 존재함을 확인할 수 있었다. 활성실험을 통해 $600^{\circ}C$로 열처리된 $Pt/Al_2O_3$ 촉매가 가장 우수한 전환율 및 선택도를 나타냄을 확인하였다.

• 한국전기전자재료학회논문지
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• 제25권5호
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• pp.398-402
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• 2012

Synthesis of $Li_2MnSiO_4$ was attempted by the conventional solid-state reaction method, and the phase formation behavior according to the change of the calcination condition was investigated. When the mixture of the three source materials, $Li_2O$, MnO and $SiO_2$ powders, were used for calcination in air, it was difficult to develop the $Li_2MnSiO_4$ phase because the oxidation number of $Mn^{2+}$ could not be maintained. Therefore, two-step calcination was applied: $Li_2SiO_3$ was made from $Li_2O$ and $SiO_2$ at the first step, and $Li_2MnSiO_4$ was synthesized from $Li_2SiO_3$ and MnO at the second step. It was easy to make $Li_2MnSiO_3$ from $Li_2O$ and $SiO_2$. $Li_2MnSiO_4$ single phase was developed by the calcination at $900^{\circ}C$ for 24 hr in Ar atmosphere as the oxidation of $Mn^{2+}$ was prevented. However, the $Li_2MnSiO_4$ was ${\gamma}-Li_2MnSiO_4$, one of the polymorph of $Li_2MnSiO_4$, which could not be used as the cathode materials in Li-ion batteries. By applying the additional low temperature annealing at $400^{\circ}C$, the single phase ${\beta}-Li_2MnSiO_4$ powder was synthesized successfully through the phase transition from ${\gamma}$ to ${\beta}$ phase.

• 한국운동역학회지
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• 제22권1호
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• pp.55-63
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• 2012

The purpose of this study was to investigate the balance differences between skilled players and less-skilled players during Hakdariseogi motion of Keumgang Poomsae in Taekwondo. To achieve the study goal, total of 10 Taekwondo athletes; 5 skilled players(S, body mass: $67.0{\pm}5.7$ kg, height: $174.0{\pm}4.8$ cm, age: $20.0{\pm}2.0$ yrs) and 5 less-skilled players(LS, body mass: $73.0{\pm}4.9$ kg, height: $176.4{\pm}6.1$ cm, age: $20.8{\pm}1.3$ yrs) participated in this study. A three-dimensional motion analysis with 8 infrared cameras and one force plate whose sampling frequency as 30 Hz and 300 Hz, respectively, were performed. Participants' motion were divided into three phases which were preparation phase(P1), performing phase(P2) and maintaining phase(P3). The range and velocities of COP, the range and RMS of ground reaction torque and displacement between COM and center of BOS of each phase were computed. In this study, at P1 and P3 which were double and single stance, respectively, the range and M-L velocities of COP revealed significantly higher in LS compared with those of S(p<.05). At P2 which was single stance, LS indicated significantly higher in range of COP and ground reaction torque, and M-L velocities of COP than those of S(p<.05). The significantly shorter displacement between COM and center of BOS, however, was found in LS compared with that of S(p<.05). The results from our study indicated that S revealed more stable performance and a better posture control ability during performing Hakdariseogi motion.

• 한국미생물·생명공학회지
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• 제26권2호
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• pp.187-194
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• 1998

수계에서 전분 가수분해효소의 transglycosylation반응을 이용하여 배당체(glycoside)를 합성하였다. Glycosyl donor인 starch와 glycosyl acceptor인 benzylalcohol을 반응기질로 선택하였다. 시판되는 9종의 당가수분해효소의 transglycosylation활성을 조사한 결과 glucose와 한 종류의 glycoside만을 생산하는 amyloglucosidase(from Rhizopus sp.)를 반응효소로 선정하였다. Amyloglucosidase에 의해 합성된 배당체는 여러 가지 분석을 통해 glucose의 1번 OH기에 benzylalcohol이 ${alpha}$형태로 결합된 benzylalcohol-${alpha}$-glucoside(BG)임을 확인하였다. 수계에서 이 효소에 의한 transglycosylation 반응의 최적조건은 starch 50mg/$m\ell$, benzylalcohol 50 mg/ml, 온도 45$^{\circ}C$, 효소량 10 unit/ml, pH 5.0, 반응시간 32시간이었으며 합성된 BG는 amyloglucosidase에 의해서는 분해되지 않았고 ${alpha}$-glucosidase에 의해 glucose와 benzylalcohol로 가수분해되었다.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.179.2-179.2
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• 2003

We have developed the novel one-pot synthetic method for regioselective and stereoselective N-protected amines through the reaction of various ethers with chlorosulfonyl isocyanate (CSI). Also, we found a novel technique to compare directly the stability of carbocations in the solution phase and established the stability order of the various carbocations. And we reported the cleavage of benzyl and p-methoxybenzyl protecting groups of alcohols and phenols in the presence of other functional groups using CSI. (omitted)

• 한국세라믹학회지
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• 제41권10호
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• pp.756-765
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• 2004

Colemanite($Ca_2B_6O_{11}{\cdot}5H_2O$)원광을 황산과 반응시켜 붕산을 추출하는 방법과 그 반응 기구에 대하여 연구하였다. colemanite에 황산을 첨가하고 가열하여 colemanite의 칼슘 성분을 황산칼슘으로 분리하고 붕산을 추출할 때, 첨가하는 황산 첨가량 은 colemanite에 존재하는 Ca 성분을 분리할 때 필요한 화학 양론적인 양보다 많아야 되며, 또한 초기 pH가 5 미만이어야 대부분의 colemanite가 분해되었다. 붕산으로 추출 시 영향을 주는 인자로는 분해온도, 분해시간, 황산 첨가량, 황산암모늄 첨가량, pH. 농축 정도 및 건조온도와 시간이었다. 황산 첨가 시 colemanite에 포함되어 있는 불순물 중 CaO와 MgO는 황산과 반응하여 침전을 형성하고, $SiO_2$는 불용 성분으로 황산칼슘과 함께 분리되고, $Al_2O_3,\;Fe_2O_3,\;TiO_2,\;Na_2O$ 등은 황산과 반응하여 액상 상태로 존재하였다. 이 액상에 암모니아를 첨가하여 존재하는 나머지 불순물을 수산화물 형태로 분리, 석출하였으며, pH 조정과 산성화, 농축, 재결정화 과정을 통하여 붕산을 제조하였다.

• 한국수소및신에너지학회논문집
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• 제23권5호
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• pp.421-428
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• 2012

The Sulfur-Iodine (SI) thermochemical hydrogen production process is one of the most promising thermochemical water splitting technologies. In the integrated operation of the SI process, the $O_2$ produced from a $H_2SO_4$ decomposition section could be supplied directly to the Bunsen reaction section without preliminary separation. A $HI_x$ ($I_2+HI+H_2O$) solution could be also provided as the reactants in a Bunsen reaction section, since the sole separation of $I_2$ in a $HI_x$ solution recycled from a HI decomposition section was very difficult. Therefore, the Bunsen reaction using $SO_2-O_2$ mixture gases in the presence of the $HI_x$ solution was carried out to identify the effect of $O_2$. The amount of $I_2$ unreacted under the feed of $SO_2-O_2$ mixture gases was little higher than that under the feed of $SO_2$ gas only, and the amount of HI produced was relatively decreased. The $O_2$ in $SO_2-O_2$ mixture gases also played a role to decrease the amount of a impurity in $HI_x$ phase by only striping effect, while that in $H_2SO_4$ phase was hardly affected.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제25회 추계학술대회논문집
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• pp.13-21
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• 2005

이 논문은 발열 반응에서 상이 변화하는 물질의 연속 방정식에서 유도되는 안정된 파면의 구조를 고려했다. 특별히 액체와 기체, 고체와 액체 사이의 동적인 파면 구조를 수치적으로 연구하였다. 1차원 충격파 구조 분석에 근거한 본 연구에 의하면 연소 시 나노 사이즈의 파면이 존재한다고 추정한다. 설명을 위해, 증발과 응축에는 n-heptane이 사용되었고, 용해와 응고에는 HMX를 사용하였다. 이 개념의 확장은 로켓 추진제와 같이 액체, 고체 연료의 넓은 범위 모두를 포함한다.