• Journal of applied mathematics & informatics
• /
• 제28권3_4호
• /
• pp.763-772
• /
• 2010

This paper deals with the existence of triple positive solutions for the nonlinear second-order three-point boundary value problem z"(t)+a(t)f(t, z(t), z'(t))=0, t $\in$ (0, 1), $z(0)={\nu}z(1)\;{\geq}\;0$, $z'(\eta)=0$, where 0 < $\nu$ < 1, 0 < $\eta$ < 1 are constants. f : [0, 1] $\times$ [0, $+{\infty}$) $\times$ R $\rightarrow$ [0, $+{\infty}$) and a : (0, 1) $\rightarrow$ [0, $+{\infty}$) are continuous. First, Green's function for the associated linear boundary value problem is constructed, and then, by means of a fixed point theorem due to Avery and Peterson, sufficient conditions are obtained that guarantee the existence of triple positive solutions to the boundary value problem. The interesting point is that the nonlinear term f is involved with the first-order derivative explicitly.

• Journal of applied mathematics & informatics
• /
• 제27권1_2호
• /
• pp.183-194
• /
• 2009

In this paper, we considered the following four-point boundary value problem $\{{x"(t)+h(t)f(t,x(t),x'(t))=0,\;0<t<1\atop%20x'(0)=ax(\xi),\;x'(1)=bx(\eta)}\$. where $0\;<\;{\xi}\;<\;{\eta}\;<\;1,\;{\delta}\;=\;ab{\xi}\;-\;ab{\eta}\;+\;a\;-\;b\;<\;0,\;0\;<\;a\;<\;\frac{1}{\xi},\;0\;<\;b\;<\;\frac{1}{\eta}$. After the discussion of the Green function of the corresponding homogeneous system, we establish some criteria for the existence of positive solutions by using the generalized Leggett-William's fixed point theorem. The interesting point is the expression of the Green function, which is a difficulty for multi-point BVP.

• 벤처창업연구
• /
• 제11권2호
• /
• pp.183-195
• /
• 2016

소상공인이 한국 경제에서 차지하는 비중이 높지만 전문적인 경영 역량이 부족하여 어려움에 처하는 경우가 많다. 그러나 이에 대한 실효성 있는 대안은 부족하다. 소상공인의 경영 문제에 관한 학계의 관심은 주로 성공적인 소상공인의 특징을 밝히거나 요인들 간의 관련성을 살펴보는 기술적이고 정량적 데이터 위주의 단편적 성과에 머물렀다. 한편 실질적인 경영 지원 과정을 통해 획득된 지식과 경험들을 이론적으로 논의하는 실천적 연구 성과는 찾아보기 어려운 형편이다. 2015년 6월부터 2015년 11월까지 경기도에 소재한 소상공인 업체들과 경기도 소재의 대학 및 경기도 소재의 중소기업진흥 기관이 공동으로 추진한 컨설팅 프로젝트에 실행 연구법을 부분 적용한 결과 트리플 힐릭스 이론 기반의 소상공인 컨설팅이 바람직한 결과를 가져온다는 사실을 알 수 있었다. 업체와 대학 그리고 공공 기관의 협업은 경영학을 배우는 학생들의 문제의식을 높이고 지식을 활용하는 기회를 부여하는 등 경영교육 상 목적 달성에 적절함도 확인했다.

• Journal of applied mathematics & informatics
• /
• 제32권1_2호
• /
• pp.75-82
• /
• 2014

In this paper, we consider the periodic boundary value problem with sign changing nonlinearity $$u^{{\prime}{\prime}{\prime}}+{\rho}^3u=f(t,u),\;t{\in}[0,2{\pi}]$$, subject to the boundary value conditions: $$u^{(i)}(0)=u^{(i)}(2{\pi}),\;i=0,1,2$$, where ${\rho}{\in}(o,{\frac{1}{\sqrt{3}}})$ is a positive constant and f(t, u) is a continuous function. Using Leggett-Williams fixed point theorem, we provide sufficient conditions for the existence of at least three positive solutions to the above boundary value problem. The interesting point is the nonlinear term f may change sign.

• Bulletin of the Korean Chemical Society
• /
• 제34권8호
• /
• pp.2425-2430
• /
• 2013

A simple, fast and robust analytical method was developed to determine imatinib in human plasma using liquid chromatography-tandem mass spectrometry with electrospray ionization in the positive ion mode. Imatinib and labeled internal standard were extracted from plasma with a simple protein precipitation. The chromatographic separation was performed using an isocratic elution of mobile phase involving 5.0 mM ammonium formate in water-5.0 mM ammonium formate in methanol (30:70, v/v) over 3.0 min on reversed-stationary phase. The detection was performed using a triple-quadrupole tandem mass spectrometer in multiple-reaction monitoring mode. The developed method was validated with lower limit of quantification of 10 ng/mL. The calibration curve was linear over 10-2000 ng/mL ($R^2$ > 0.99). The method validation parameters met the acceptance criteria. The spiked samples and standard solutions were stable under conditions for storage and handling. The reliable method was successfully applied to real sample analyses and thus a pharmacokinetic study in 27 healthy Korean male volunteers.

• 농업생명과학연구
• /
• 제46권5호
• /
• pp.65-72
• /
• 2012

Salmonellosis is a widespread bacterial zoonosis that commonly causes enterocolitis and foodborne poisoning leading to an extensive economic loss in domestic animal industry. Considerably, the emergence of multidrug resistant strains of Salmonella spp. induces further severe problems affecting public health. The present report was designated to investigate the antibacterial efficacies of three common disinfectants including an oxidizing compound disinfectant (OXC), a triple salt (TS) and a quaternary ammonium compound (QAC) against Salmonella typhimurium subjected to the preliminary changes of drug temperature. All solutions of three disinfectants were pre-incubated at different temperature (22, 37 and $63^{\circ}C$) for 1 h prior to exposure to bacteria. The disinfectants and bacteria were diluted with distilled water (DW), hard water (HW) or organic matter suspension (OMS) according to treatment condition. Under the DW condition, the disinfectant efficacy of the QAC at $63^{\circ}C$ was higher than that of $22^{\circ}C$. Furthermore, under HW diluent the disinfectant efficacy of the TS pre-warmed at both of 37 and $63^{\circ}C$ were increased compared to that of $22^{\circ}C$. Considerably, the efficacy of pre-warmed QAC at both of 37 and $63^{\circ}C$ under the OMS diluent were higher than that of $22^{\circ}C$. Conclusively, prewarming at higher temperatures have positive effects on the stability of the antibacterial efficacies of TS and QAC.