• 한국세라믹학회지
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• 제50권1호
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• pp.70-74
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• 2013

Dependence of microwave dielectric properties on the crystallization behaviors of $CaMgSi_2O_6$ (diopside) glass-ceramics was investigated with different heat treatment methods (one and/or two-step). The crystallization behaviors of the specimens, crystallite size and degree of crystallization, were evaluated by differential thermal analysis (DTA), scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis by combined Rietveld and reference intensity ratio (RIR) methods. With an increase in heattreatment temperature, the dielectric constant (K) and the quality factor (Qf) increased due to the increase of the crystallite size and degree of crystallization. The specimens heat-treated by the two-step method had a higher degree of crystallization than the specimens heat-treated by the one-step method, which induced improvement in the quality factor (Qf) of the specimens.

• Mass Spectrometry Letters
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• 제6권1호
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• pp.21-25
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• 2015

In this paper, I describe the importance of matrix spraying conditions in imaging mass spectrometry (IMS) to obtain successful imaging results. My developed matrix application methodology, which is a "two-step matrix application" sequentially combined with matrix sublimation and spraying matrix solution can provide high reproducibility and high ion yield compared with a conventional direct spraying method. However, insufficient IMS results were obtained occasionally despite the two-step method. Therefore, I wanted to characterize the methodology to continuously provide high quality data. According to my results, the sublimation time was not a strict parameter, and the most important step was the first spraying condition. This means that the extraction conditions from the tissue section and co-crystallization of the matrix were the most important factors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.370-374
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• 1988

This paper is concerned with the investigation of the impurity redistribution process in a two step diffusion. In integrated circuit technology, two step boron diffusion involving a deposition step followed by a drive-in step in commonly encounted. The drive-in process is usually performed in oxidizing atmosphere resulting in redistribution of impurity (boron) within the semiconductor. This paper proposes a new numerical analysis method; Bounary Element Method to determine impurity profile at the arbitrary point in domain by its coordinate and boundary value.

• Kyungpook Mathematical Journal
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• 제56권2호
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• pp.311-327
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• 2016

In this paper, we propose an error embedded Runge-Kutta method to improve the traditional embedded Runge-Kutta method. The proposed scheme can be applied into most explicit embedded Runge-Kutta methods. At each integration step, the proposed method is comprised of two equations for the solution and the error, respectively. These solution and error are obtained by solving an initial value problem whose solution has the information of the error at each integration step. The constructed algorithm controls both the error and the time step size simultaneously and possesses a good performance in the computational cost compared to the original method. For the assessment of the effectiveness, the van der Pol equation and another one having a difficulty for the global error control are numerically solved. Finally, a two-body Kepler problem is also used to assess the efficiency of the proposed algorithm.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.460-463
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• 1999

A new multi-step voltage source inverter is proposed in this paper. The proposed scheme is composed of the double-connected 12-step inverter with an auxiliary circuit. The auxiliary circuit includes two voltage dividing capacitors, two switching devices and a low KVA autotransformer. The resultant system is shown to be a 24-step inverter suitable for large scale SVC applications in which the PWM method can not be employed. The design parameters are derived from the analysis of voltages and currents by means of switching functions. The simulation results verify the proposed concept.

• East Asian mathematical journal
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• 제27권3호
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• pp.319-337
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• 2011

We approximate a locally unique solution of a nonlinear equation in a Banach space setting using an inexact two-step Newton-type method. It turn out that under our new idea of recurrent functions, our semilocal analysis provides tighter error bounds than before, and in many interesting cases, weaker sufficient convergence conditions. Applications including the solution of nonlinear Chandrasekhar-type integral equations appearing in radiative transfer and two point boundary value problems are also provided in this study.

• 반도체디스플레이기술학회지
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• 제14권1호
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• pp.7-11
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• 2015

In this paper, an automatic focusing method has been proposed for speedy and reliable measurement and inspection in industry. It is very difficult to determine focusing step size and moving direction in one camera autofocusing. The proposed method can improve speed and accuracy of focusing by using the optical axis interval of two cameras, which is automatically set up as focusing step size. Also, it can determine moving direction from focus value comparisons of two cameras, and then solve ambiguity of one camera focusing. Its performance is verified by experiments. It is expected that it can apply to optical system for measurement and inspection in industry fields.

• 한국재료학회지
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• 제4권4호
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• pp.459-465
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• 1994

a-측으로 배향된 $YBa_2Cu_3O_{7-\delta}$ 고온 초전도 박막을 $LaAIO_{3}$(100)단결정 기판에 이중 타게트 off-axis rf마그네트론 스퍼터링법으로 증착하였다. 박막은 기판온도(Ts)$590^{\circ}C$와 $680^{\circ}C$사이에서 단일공정으로 증착하는 one-step방법과, $590^{\circ}C$의 저온에서 a-축으로 배향된 YBCO박막(두께-30nm)을 면저 만들어 틀로 작용시킨 후 그 틀위에 나머지 부분을 기판온도를 승온하면서 증착하는 방법인 two-step방법 등 두 가지 방법을 사용하여 증착시켰다. one-step방법에서는 $T_s$가 증가함에 따라 감소하였으며, ($00 \ell$)피크는 증가하였다. Two-step방법으로 증착한 박막은 증착속도가 감소함에 따라 (h00)피크가 우세하게 나타났다. 박막의 미세구조는 a-축, c- 축 배향성이 혼재하여 핀홀과 같은 결함들이 생성되었다. 모든 경우 $T_s$가 감소함에 따라 a-축 배향성은 우세하였으나 전기적 특성은 저하되었고, 긴 전이온도 폭을 가졌다.

• 한국농공학회지
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• 제37권E호
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• pp.1-9
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• 1995

It is shown that two step power transformation is more efficient for the normalization of frequency distribution with the coefficient of skewness of zero in comparison with others including SMEMAX and power transformations. It is confirmed that the design low flows calculated using power and two step power transformations used in this study are generally nearer to the observed data as compared with those of SMEMAX transformation at all return periods in the applied watersheds of the Kum, Naktong and Yongsan rivers in Korea.

• 대한수학회논문집
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• 제15권1호
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• pp.173-181
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• 2000

The objective of this paper is to study two dimensional steady gravitational waves on the interface between two immiscible, inviscid and incompressible fluids bounded above by a horizontal rigid boundary and below by a rigid step. A KdV equation for the first order perturbation in an asymptotic expansion can appear. However the coefficient of the KdV theory fails in that case. By a unified asymptotic method, we overcome this difficulty and derive a modified KdV equation with forcing. We find homogeneous steady solutions and present numerical solutions.