• 한국기계가공학회지
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• 제19권6호
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• pp.29-35
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• 2020

Transition Nozzles are used in industrial air-cooled heat exchangers and widely used in industrial sites as an important component in the heat energy transfer between a heat source and an actuating fluid. There is a worldwide demand for transition nozzles with various materials and shapes, depending on the use environment. This paper aims to improve the transition nozzle forging process suitable for the production of many varieties using Steps 1 to 6 of the TRIZ Methodology for Problem Solving. By utilizing the TRIZ Methodology, this study derives a method to design a variable mold, which is more efficient and can reduce costs compared with having to use several molds. To verify the suitability of the methods derived using the TRIZ technique, a forging analysis is performed on a transition nozzle using DEFORMⓇ, a commercial program for plasticity analysis, and the nozzle material is evaluated for damage as a result of deformation of the transition nozzle thickness. The derived methods can be applied to transition nozzle formation equipment to improve the efficiency of the formation process.

• 한국통신학회논문지
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• 제23권7호
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• pp.1770-1776
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• 1998

밀리미터파 대역에서 동축선로-마이크로스트립 변환구조가 지니는 여러 가지 문제점을 극복하기 위해서 antipodal finline을 이용하는 구형 도파관-마이크로스트립 변환구조를 설계, 제작하였다. 반복 실험을 통한 실험적 최적화 및 수치해석을 통한 해석적 최적화 과정을 통해 작은 삽입손실 갖는 변환구조를 설계하였다. 실험적, 해석적으로 최적화된 변환구조는 Ka-band(26.5 - 400Hz)에서 변환구조당 0.3 -0.4 dB의 작은 삽입손실을 나타냈다. Finline 변환 구조를 사용하는 경우, 중요 설계변수가 기판상에 있으므로 재현성이 뛰어나며 정밀한 금속가공이 필요치 않아 동 축선로-마이크로스트립 변환구조의 문제점을 극복할 수 있었다. 또한, 기존의 임피던스 변환기를 개선시키기 위해 새롭게 지수함수 유전체 임피던스 변환기를 시도하였으며 이를 통하여 0.54dB 정도의 삽입손실을 개선시켰다.

• 전자공학회논문지B
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• 제30B권2호
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• pp.1-7
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• 1993

In this paper, we show that Petri nets can be applied to design and reliability analysis of concurrent, parallel and embedded mode system such as a lift system that is familiar to our daily life. Modeling the behavioral characteristics of the lift system we extend the standard Petri nets by nadditionally constant timed transition, fault transition, stochastic imed ttransition and conditional transition concepts. Likewise, we present esults of rdesign and analysis of the system. This method can be applied to esign and danalysis of any other concurrent systems.

• Journal of Mechanical Science and Technology
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• 제15권11호
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• pp.1499-1506
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• 2001

Various transition elements are used in general for the effective finite element analysis of complicated mechanical structures. In this paper, a solid-to-beam transition finite element, which can b e used for connecting a C1-continuity beam element to a continuum solid element, is proposed. The shape functions of the transition finite element are derived to meet the compatibility condition, and a transition element equation is formulated by the conventional finite element procedure. In order to show the effectiveness and convergence characteristics of the proposed transition element, numerical tests are performed for various examples. As a result of this study, following conclusions are obtained. (1) The proposed transition element, which meets the compatibility of the primary variables, exhibits excellent accuracy. (2) In case of using the proposed transition element, the number of nodes in the finite element model may be considerably reduced and the model construction becomes more convenient. (3) This formulation method can be applied to the usage of higher order elements.

• 응용통계연구
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• 제24권4호
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• pp.709-719
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• 2011

We investigate the latent stage-sequential patterns of drinking behaviors of U.S. adolescents who have started to drink by age 14 years (seven years before the legal drinking age). A multiple-group latent transition analysis(LTA) with logistic regression is employed to identify the subsequent patterns of drinking behaviors among early-onset drinkers. A sample of 1407 early-onset adolescents from the National Longitudinal Survey of Youth(NLSY97) is analyzed using maximum-likelihood estimation. The analysis demonstrates that early-onset adolescents' drinking behaviors can be represented by four latent classes and their prevalence and transition are influenced by demographic factors of gender, age, and race.

• Bulletin of the Korean Chemical Society
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• 제7권1호
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• pp.20-23
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• 1986

A reduced condition for liquid-gas phase transition from the singularity of compressibility is derived using diagrammatic approach and is examined in the hard sphere system. The condition turns out that the Percus-Yevick and the Hyper-Netted-Chain approximation never conceive the idea of phase transition, and explains that the liquid-gas transition does not exist in hard sphere system. The solid-fluid transition is considered on the viewpoint of correlation function and diagrammatic analysis.

• 중환자간호학회지
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• 제12권2호
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• pp.50-60
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• 2019

Purpose : The purpose of this study was to identify the attributes, antecedents, and consequences of the transition of simulation-based learning (SBL) in nursing schools. Methods : The study was conducted in accordance with Walker and Avant's conceptual analysis process. We searched MEDLINE, CINAHL, EMBASE, Google Scholar, and RISS (Korean Education and Research Information Service) databases, resulting in nine studies for an in-depth review. Results : The attributes of transition of SBL include (1) preparing for a professional role, (2) practicing in a real clinical setting, and (3) progressing toward expected competency. Antecedents of the concept include novice status, changing roles, clinical experience in controlled settings, and expected competency in the clinical setting. Conclusion : The transition of SBL includes the important feature of progression toward expected competency. Further research is needed to identify graduate nurses' experiences during this transition to establish a strategy for improving it and developing a measurement tool that reflects attributes of the concept.

• Human Ecology Research
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• 제59권2호
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• pp.199-213
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• 2021

The purpose of the study was to apply latent transition analysis to the work-family balance of working mothers with a child in elementary school by focusing on the effect of antecedents on both work-family balance typology and the transition between typologies. Data from 400 working mothers who participated in the eighth and eleventh waves of the Panel Study on Korean Children were used. The results can be summarized as follows. First, the latent profile analysis of working mothers whose children were in the first grade classified the work-family balance types as 'contradictory' or 'beneficial' and of working mothers whose children were in the fourth grade as 'conflictual', 'contradictory', 'high beneficial', 'low beneficial' or 'beneficial'. Second, working mothers whose work-family balance was 'contradictory' or 'beneficial' when their children were in the first grade mostly had, respectively, a 'low beneficial' or a 'high beneficial' balance when their children were in the fourth grade. Third, the probability of being classified into each type differed according to subjective happiness and marital conflict in the first grade, and marital conflict and social support in the fourth grade. Moreover, marital conflict and social support were significant in the transition between the types of work-family balance. The study showed that the types of work-family balance differed for each time point for individual working mothers. The study also highlighted the importance of parenting-related personal, family and social factors in determining the work-family balance type and transition between types.

• 전기학회논문지P
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• 제67권3호
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• pp.149-154
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• 2018

We consider the system is subject to the linearly polarized oscillatory external field. We study the optical quantum transition Line shapes(QTLS) which show the absorption power and the quantum transition line widths(QTLW) of electron-piezoelectric phonon interacting system. We analyze the magnetic field dependence of the QTLS and the QTLW in various cases. In order to analysis the quantum transition, we compare the magnetic field dependence of the QTLW and the QTLS of two transition process, the intra-Landau level transition process and the inter-Landau level transition process.

• Steel and Composite Structures
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• 제43권3호
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• pp.363-373
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• 2022

As a key reinforcement connection between a tower and a substructure in offshore wind turbine system, the transition piece is inevitably subjected to cyclic dynamic environmental loads such as wind, current and wave. Therefore, well designed transition piece with high strength and good fatigue resistance is of great significance to the structural safety and reliability of offshore wind power systems. In this study, the structural behavior of the transition piece was studied by an extensive sets of finite element analyses. Three widely used types of transition piece were considered. The characteristics of stress development, fatigue life and weight depending on the type of the transition piece were investigated in the ultimate limit state (ULS) and the fatigue limit state (FLS) of a 5-MW offshore wind turbine to be placed in Korea. An optimal form of the transition piece was proposed based on this parametric study.