• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.267-267
• /
• 2012

$TiO_2$-Ni inverse catalysts were prepared using atomic layer deposition (ALD) process and catalytic $CO_2$ reforming of methane (CRM) reaction over catalysts (either bare Ni or $TiO_2$ coated-Ni particles) were performed using a continuous flow reactor at $800^{\circ}C$. $TiO_2$-Ni inverse catalyst showed higher catalytic reactivity at initial stage of CRM reactions at $800^{\circ}C$ comparing to bare Ni catalysts. Moreover, catalytic activity of $TiO_2$/Ni catalyst was kept high during 13 hrs of the CRM reactions at $800^{\circ}C$, whereas deactivation of bare Ni surface was started within 1hr under same conditions. The results of surface analysis using SEM, XPS, and Raman showed that deposition of graphitic carbon was effectively suppressed in a presence of $TiO_2$ nanoparticles on Ni surface, thereby improving catalytic reactivity and stability of $TiO_2$/Ni catalytic systems. We suggest that utilizing decoration effect of metal catalyst with oxide nanoaprticles is of great potential to develop metal-based catalysts with high stability and reactivity.

• Bulletin of the Korean Chemical Society
• /
• 제34권12호
• /
• pp.3811-3816
• /
• 2013

Nucleophilic substitution reactions of ethyl methyl (2), ethyl propyl (4) and diisopropyl (7) chlorothiophosphates with substituted anilines and deuterated anilines are investigated kinetically in acetonitrile at $55.0^{\circ}C$. A concerted mechanism is proposed based on the selectivity parameters. The deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) are secondary inverse ($k_H/k_D=0.66-0.99$) with 2, primary normal and secondary inverse ($k_H/k_D=0.78-1.19$) with 4, and primary normal ($k_H/k_D=1.06-1.21$) with 7. The primary normal and secondary inverse DKIEs are rationalized by frontside attack involving hydrogen bonded, four-center-type transition state, and backside attack involving in-line-type transition state, respectively. The anilinolyses of ten chlorothiophosphates are examined based on the reactivity, steric effect of the two ligands, thio effect, reaction mechanism, DKIE and activation parameter.

• 한국운동역학회지
• /
• 제15권2호
• /
• pp.57-67
• /
• 2005

The purpose of this study was to analyze the kinetic factors of the golf driver swing using the Inverse Dynamics function. For this purpose, joint force were calculated. In order to test the possibility of Inverse Dynamics function(motion-dependent interaction), a triple segmental system was set for wrist, left shoulder and lumbar and joint force working on the anatomical joint region was estimated. For this study, 7 professional golfers were sampled, and then, their driver swings were recorded with two high-speed digital video cameras (180 frames/sec.) to be synthesized into 3-dimensional images and coordinated. Then, Eular's equation was used to produce some kinematic data, which were used to calculate joint force and torque with Newton's function. All data were calculated using LabVIEW 6.1 graphic program. The results of this study can be summarized as follows; It was found that the joint force was generated on wrist, shoulder and lumbar joints in the direction of the target, and that the joint force was stronger in the direction of target immediately before impact. The joint force was generated towards the target to activate the nodes, and then, it was generated in the reverse direction to increase the speed during impact.

• 공업화학
• /
• 제28권2호
• /
• pp.141-152
• /
• 2017

1,2,4,5-테트라진 유도체를 이용한 inverse electron-demand Diels-Alder (IEDDA) 반응은 다양한 생체물질, 고분자, 나노 물질 복합체의 효율적인 합성에 폭넓게 활용되고 있다. IEDDA는 유기용매에서뿐만 아니라 생리학적 조건 하에서도 매우 특이적이며 빠른 반응속도를 가지고 있는 것으로 알려져 있다. 이러한 특성으로 인해 본 반응은 다양한 생물학적 활성을 가지는 물질의 방사성동위원소 표지와 분자영상 및 질병 치료를 위한 방사성의약품 개발에도 활발히 응용되고 있다. 본 리뷰 논문은 IEDDA 반응을 방사화학 및 핵의학 분야에서 이용한 최근 연구 동향 및 연구 결과 그리고 향후 전망에 대해 소개하고자 한다.

• Journal of applied mathematics & informatics
• /
• 제20권1_2호
• /
• pp.17-34
• /
• 2006

Inverse coefficient identification problems associated with the fourth-order Sturm-Liouville operator in the steady state Euler-Bernoulli beam equation are investigated. Unlike previous studies in which spectral data are used as additional information, in this paper only boundary information is used, hence non-destructive tests can be employed in practical applications.

• Journal of applied mathematics & informatics
• /
• 제15권1_2호
• /
• pp.485-493
• /
• 2004

This paper presents the interesting properties of a certain patterned matrix that plays an significant role in the statistical analysis. The necessary and sufficient condition on the existence of the inverse of the patterned matrix and its determinant are derived. In special cases of the patterned matrix, explicit formulas for its inverse, determinant and the characteristic equation are obtained.

• 청정기술
• /
• 제18권1호
• /
• pp.38-42
• /
• 2012

정보 전달의 수단으로의 빛을 제어하는 기술에 대한 연구가 활발한 가운데, 최근 가장 각광 받고 있는 것이 광결정(Photonic crystals)을 갖는 물질이다. 이를 합성하는 다양한 방법 중에서 초임계 증착법(Supercritical deposition)을 사용하면, 복잡한 내부 구조물까지의 반응물의 침투가 용이하여 신속하고 효율적인 공정이 가능하다. 본 논문에서는 비독성, 비인화성 등으로 친환경 초임계 용매인 초임계 이산화탄소(Supercritical carbon dioxide) 분위기 하에서 고분자 콜로이드 주형에 금속 알콕사이드를 코팅하는 방법으로 매크로 기공을 갖는 역 오팔(Inverse opals) 구조물을 합성하였다. 반응온도와 압력은 $40^{\circ}C$와 80 bar로 고정하였으며, 반응 시간과 반응물의 비율을 조절하여 역 오팔의 구조의 변화를 살펴보았다. 실험에는 금속 알콕사이드로써 Tetraethyl orthosilicate (TEOS)와 Titanium (IV) isopropoxide (TTIP)가 사용되었으며, 각각을 통하여 실리카와 타이타니아 역 오팔을 합성할 수 있었다.

• 대한수학회지
• /
• 제48권2호
• /
• pp.311-327
• /
• 2011

This paper is devoted to simplified Tikhonov regularization for two kinds of parabolic equations, i.e., a sideways parabolic equation, and a two-dimensional inverse heat conduction problem. The measured data are assumed to be known approximately. We concentrate on the convergence rates of the simplified Tikhonov approximation of u(x, t) and its derivative $u_x$(x, t) of sideways parabolic equations at 0 $\leq$ x < 1, and that of two-dimensional inverse heat conduction problem at 0 < x $\leq$ 1, respectively.

• 응용통계연구
• /
• 제10권2호
• /
• pp.293-308
• /
• 1997

일변량 분할 역회귀 방법은 일반화 회귀모형에서 효과적인 차원축약방향과 공간을 추정하는 방법이다. 본 논문에서는 두 일반화 회귀모형을 동시에 고려하여 효과적인 차원축약방향과 공간을 추정하는 방법으로 이변량 분할 역회귀를 제안한다. 이러한 이변량 분할 역회귀 방법은 모형식이 선형, 이차형, 삼차형, 비선형 등의 여러 모형식에서 효과적인 차원축약방향을 추정하며, 일변량 분할 역회귀에 비하여 모형에 존재하는 오차에 크게 영향을 받지 않고 효과적인 차원축약방향을 추정한다. 특히 모형식이 대칭의 이차형인 경우에 일변량 분할 역회귀 방법이 효과적인 차원축약방향을 추정하지 못하는 문제를 해결할 수 있다.

• 한국공간구조학회논문집
• /
• 제2권1호
• /
• pp.75-84
• /
• 2002

In this study, the 'force density method' for shape finding of cable net structures is presented. This concept is based on the force-length ratios or force densities which are defined for each branch of the net structures. This method renders a simple linear 'analytical form finding' possible. If the free choice of the force densities is restricted by further condition, the linear method is extended to a nonlinear one. The nonlinear one can be applied to the detailed computation of networks. In this paper, the general inverse matrix is introduced to solve the nonlinear equilibrium equation including Jacobian matrix which is rectangular matrix. Several examples for linear and nonlinear analysis applied additional constraints are presented. It is shown that the force density method is suitable for form finding of cable net and the general inverse matrix can be applied to solve the nonlinear equation without Lagrangian factors.