• Bulletin of the Korean Chemical Society
• /
• 제35권12호
• /
• pp.3567-3570
• /
• 2014

The most stable adsorption structures and energies of four tautomers of 3-methyl-5-pyrazolone (keto-1, enol-1, keto-2, and enol-2) on Ge(100) surfaces were investigated using density functional theory (DFT) calculations. The enol-1, keto-2, and enol-2 tautomers, but not the keto-1 tautomer, were found to exhibit stable adsorption structures on the Ge(100)-$2{\times}1$ surface. Of these three adsorption structures, that of enol-2 is the most stable.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.888-893
• /
• 2008

In This paper proposes the control algorithm for quadruped robots on irregularly sloped uneven surface. Body balance is important in stable running locomotion. Since the body balance is determined by the forces applied at the feet during touchdown phase, the ground reaction force is controlled for stable running. To control the forces at each foot, the desired force is generated. The generated desired force is compared with actual contact force, then, the difference between them modifies the foot trajectory. The desired force is generated by combination of the rate change of the angular and linear momentum at flight. Then the rate change of momentum determines each force distribution. The distribution of the force is carried out by fuzzy logic. The computer simulation is carried out with the commercial software RecurDyn$^{(R)}$. Dynamic model simulation program show that the stable running on the irregularly sloped uneven surface are accomplished by the proposed method.

• Journal of the Korean Statistical Society
• /
• 제32권4호
• /
• pp.337-357
• /
• 2003

This paper introduces new measures for the stability of slope estimation on the second order response surface at a point and on a sphere. As a measure of point stability of slope estimation, we suggest a point dispersion measure of slope variances over all directions at a point. A spherical dispersion measure is also proposed as a measure of spherical stability of slope estimation on each sphere. Some designs are studied to explore the usefulness of the proposed measures. Using the point dispersion measure, another concept of slope rotatability called equally-stable slope rotatability is proposed as a useful property of response surface designs. We provide a set of conditions for a design to have equally-stable slope rotatability.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.151.5-151
• /
• 2001

Sliding mode control is investigated for a discrete-time system with uncertainties. The narrowest neighborhood of the sliding surface is shown in which the state can remain. The range is determined by the upper bound of the absolute value of the uncertainty and the equation of the sliding surface. A sliding mode control algorithm is proposed to keep the state there without requiring an enormous input. Under the presence of the system parameter variations, the origin is not always stable although the sliding surface represents the stable dynamics and the state is kept in this neighborhood. The condition for the origin to be stable is investigated. Furthermore, the problems occurring when a continuous-time sliding mode control being ...

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2018년도 춘계학술대회
• /
• pp.580-583
• /
• 2018

본 연구는 지지면에 따른 발목균형훈련이 비만중년여성의 고유수용성감각, 균형 및 근력 미치는 영향을 알아보고자 하였다. 연구에 동의한 중년여성 30명중 불안정한 지지면에서 훈련을 시행한 실험군I의 15명과 안정 지지면에서 훈련을 시행한 실험군II의 15명에게 총 6주간 매회 30분씩 훈련하였다. 훈련효과를 알아보기 위해 훈련 전 고유수용성은 Dualer IQ 디지털 경사계로 검사를 시행하였고 균형은 BT4로 검사하고 근력은 도수근력검사기로 검사를 하고 훈련 후 다시 재측정하였다. 이에 실험군I,II 모두 고유수용, 균형, 근력검사에서 유의한 차이를 보였다. 이에 불안정한 지지면과 안정된 지지면에서의 발목균형운동은 비만중년여성의 고유수용성, 균형, 근력이 향상되는 프로그램이다.

• KSTLE International Journal
• /
• 제4권2호
• /
• pp.60-65
• /
• 2003

Tribological properties of novolac resin composites containing particulate barite (BaSO$_4$) or potassium titanate (K$_2$Oㆍ6(TiO$_2$))whiskers (two typical space fillers for commercial automotive brake linings) were investigated. The emphasis of the current investigation was given to the effect of the two fillers on the propensity of the stick-slip phenomena and formation of stable rubbing surface. A block-on-disk type tribometer was used for friction assessment. Results showed that the BaSO$_4$-filled composite produced large friction force oscillations at slow sliding speeds and created severe damage on the gray iron counter surface. On the other hand, the composite with $K_2$Oㆍ6(TiO$_2$) whiskers formed a stable rubbing surface and showed smooth sliding behavior without large friction force fluctuation. The microscopic observation of the rubbing surface revealed that the $K_2$Oㆍ6(TiO$_2$)whiskers played a key role in the formation of stable rubbing surface and smooth sliding behavior by effectively reinforcing the resin.

• 한국전자통신학회논문지
• /
• 제8권9호
• /
• pp.1383-1389
• /
• 2013

본 연구는 불안정지지면 훈련을 통한 발목관절위치감각의 변화와 동요면적 변화간의 상관관계를 알아보고자 실시하였다. 건강한 성인 남녀 48명을 대상으로 무작위로 불안정지지면군(n=24)과 안정지지면군(n=24)으로 나누어 동일한 운동 프로그램을 적용하여 주 3회씩 6주 동안 실시하였다. 불안정지지면군은 균형운동 패드에서, 안정지지면군은 단단한 지면에서 운동을 실시하였다. 운동 전 후에 발목관절위치감각의 변화와 동요면적의 변화를 알아보았다. 그 결과, 불안정지지면군에서 발목관절위치감각 오차와 동요면적은 유의하게 감소하였다(p<.05). 그리고 불안정지지면군에서만 발목관절위치감각 오차의 변화량과 동요면적 변화량간의 유의한 상관관계를 보였다. 따라서 본 연구는 불안정지지면에서의 고유수용성감각 운동을 통해 발목관절위치감각 변화와 동요면적 변화간의 유의한 상관관계가 있음을 알 수 있었다.

• Korean Journal of Hydrosciences
• /
• 제6권
• /
• pp.39-49
• /
• 1995

The surface hydrology of large land areas is susceptible to several preferred stable states with transitions between stable states induced by stochastic fluctuation. This comes about due to the close couping of land surface and atmospheric interaction. An interesting and important issue is the duration of residence in each mode. Mean transition times between the stable modes are analyzed for different model parameters or climatic types. In an example situation of this differential equation exhibits a bimodal probability distribution of soil moisture states. Uncertainty analysis regarding the model parameters is performed using a Monte-Carlo simulation method. The method developed in this research may reveal some important characteristics of soil moisture or precipitation over a large area, in particular, those relating to abrupt change in soil moisture or preciptation having extremely variable duration.

• Bulletin of the Korean Chemical Society
• /
• 제19권10호
• /
• pp.1054-1059
• /
• 1998

Fluorescence and dynamic light scattering measurements were applied to the study of formation and structure of aggregated colloidal particles in modified poly(ethylene-co-methylacrylate) ionomers in aqueous solution. Both 8-anillino-l-naphthalene-sulfonic acid (ANS) and pyrene were used as fluorescence probe to obtain the information on the structure of particle surface and inside, respectively. Three different ionomers used in this study started to aggregate at very dilute concentration, 3-8 x 10-6 g/mL. In this study, we demonstrate that the polyethylene ionomers can form stable nanoparticles. The hydrophobic core made of the polyethylene backbone chains is stabilized by the ionic groups on the particle surface. Such a formed stable nanoparticles have a relatively narrow size distribution with an average radius in the range of 27-48 nm, depending on the kind of ionic groups. Once the stable particles are formed, the particle size distributions were nearly constant. This study shows another way to prepare surfactant-free polyethylene nanoparticles.

• Journal of Pharmaceutical Investigation
• /
• 제37권1호
• /
• pp.7-13
• /
• 2007

To produce stable polymer coating layer using the interaction between metal stent and polymer layer, Ahx-HSAB was synthesized by coupling 6-aminoheanoic acid (Ahx) with N-Hydroxy succinimidyl 4-azidobenzonate (HSAB) containing photo reactive group. Then, Ahx-HSAB was applied to self·assembled monolayer (SAM) on $TiO_2$-coated surface, since one end of Ahx-HSAB was carboxyl acid which was known to be able to interact with $TiO_2$ surface. That SAM layer was incubated in 1% polycaprolacton (PCL) solution and photoreacted by ultraviolet light (254 nm) to produce the chemical bond between SAM and polymer layer, followed by PCL polymer coating ({\sim}5\;{\mu}m$) by the method of spray coating. The surface change was investigated by measuring of contact angle of the surface. The contact angle values of stainless steel (SS) surface, $TiO_2$-coated surface, SAM layer by Ahx-HSAB, photoreacted surface with PCL and PCL layer by spray coating were 70.48${\pm}$1.89, 38.57${\pm}$3.31, 60.14${\pm}$2.21, 54.91${\pm}$2.70 and 56.47${\pm}$2.12, respectively. The stability of polymer layers was tested by incubation of PCL-coated plates in 0.1M PBS buffer (pH 7.4, 0.05%, Tween 80) with vigorous shaking (200 rpm). While the poiymer layer prepared by these processes showed the intact surface morphology over 3 days, the polymer layers prepared by spray coating of PCL onto SS plate (control 1) and $TiO_2$-coated SS plate (control 2) were Peeled off in 3 days. Thus, the polymer coating method using SAM and photoreaction seems to be a effective method to obtain the stable polymer layer onto SS surface.