• Journal of the Korean Society of Combustion
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• v.9 no.2
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• pp.1-9
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• 2004

Activation energy asymptotics (AEA) for Linan#s diffusion-flame regime is revisited in this paper. The main purpose of the paper is to carefully re-examine each AEA analysis step in order to clarify the some concepts that are often misunderstood among the ordinary practitioners of the AEA. Particular attention is focused on the different AEA regimes arising from the double limit of large Zel#dovich and Damkohler numbers. In addition, the expansion procedures are shown in detail and the method that the turning point condition, commonly known as the Linan#s extinction condition, is found is explained.

• Journal of the Korean Society for Precision Engineering
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• v.7 no.2
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• pp.85-94
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• 1990

In automatic metal cuttings, the chip control is one of the serious problems. So the automatic detection of chip forms is essential to the chip control in automatic metal cuttings. Cutting experiments were carried out under the variety of cutting conditions (cutting speed, feed, depth of cut and tool geometry) and with workpiece made of steel (S45C), and cutting forces were measured in-processing by using a piezoelectric type Tool Dynamometer. In this report, the frequency analysis of dynamic components, the upper frequency distributions, the ratio of RMS values, the numbers of null point and the probability density were calculated from the dynamic componeents of cutting forces filtered through various band pass filters. Experimental results showed that computer chip form monitoring system based on the cutting forces was designed and simulated and that 6 type of chip forms could be detected while in-process machining.

• Journal of the Korea Safety Management & Science
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• v.18 no.4
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• pp.39-46
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• 2016

In this paper, the relationship between energy consumption in the logistics industry and economic growth of Tumen River region from 1995 to 2014 is empirically analyzed by using the EKC model theory. The results show that there is a turning point in the Kuznets curve of carbon emission in TumenRiverregion. And it has the characteristic sof "invertedU" curve, which conforms to the environmental Kuznets curve hypothesis. Meanwhile it is stil lintherisingstage. According to the analysis results, it is proposed to set up the concept of low carbon logistics, optimize the energy structure, strengthen the information construction, and establish low-carbon development mechanism and so on.

• Current Optics and Photonics
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• v.3 no.3
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• pp.227-235
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• 2019

With slimmer, lighter and all-reflective imaging systems in high demand for consumer and military applications, coaxially folded optical image systems are widely considered because they can extend focal length and reduce track length. Most of these systems consist of multiple surfaces, and these surfaces are machined on one element or grouping processing on two elements. In this paper, we report and first experimentally demonstrate an all-aluminum all-reflective optical system which consists of two optical elements, with two high order aspherical surfaces in each element. The coaxially folded system is designed with Seidel aberration theory and advanced optimization with Zemax. The system is made of all-aluminum material processing by single point diamond turning (SPDT). On this basis, we completed the system integration and performed an imaging experiment. The final system has the advantages of short track length and long focal length and broad application prospects in the micro-unmanned aerial vehicle field.

• Journal of the Korean Society of Food Culture
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• v.38 no.2
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• pp.83-98
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• 2023

This study summarizes the research methods, subjects, research processes, and achievements of major researchers by analyzing previous research results on Korean food history. The goal of the current study aimed to seek the methodology and direction of 'food history research'. Literature data from 1945 to 2022 were examined. Results of excavation research on ancient food literature were divided into the following stages: the 1980s, when the foundation for 'cataloging' was laid, and the 2000s, when 'digitization' was achieved. Achievements of each period were collected, and the achievements and limitations were analyzed. Next, the research results were classified into 'Food technology history', 'Recipe change history', and 'Food culture and dietary history'. We observed that around the 2000s, anthropology and folklore research perspectives were reflected, and the research on 'history of diet' reached a turning point. Our results indicate the possibility that food history can develop as a special historical area. This could be achieved by establishing an exchange system with other disciplines and creating a systematic curriculum.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1118-1124
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• 2023

Experimental study on the fluidelastic instability (FEI) of a curved tube bundle in single phase downward cross flow is investigated for the design qualification and analysis input preparation of helical coiled steam generator tubing. A 6×9 normal square curved tube array with equal and different vertical/horizontal pitch-to-diameter ratio was under-tested up to 6 m/s in term of gap flow velocity to measure the critical velocity for FEI. The critical velocity for FEI was measured at the turning point from the vibration amplitude plot along the gap flow velocity. Our test results were compared with straight tube results and published data in the design guideline. The applicability of the current design guidelines to a curved tube bundle is also assessed. We found that introducing frequency difference in a curved tube array increases the critical velocity for fluidelastic instability.

• Korean Journal of Social Welfare
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• v.60 no.3
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• pp.5-30
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• 2008

The purpose of this study is to propose a practical intervention program for the women who got out of prostitution. For the research we selected the seven women who had ever engaged in prostitution by snowball sampling. Qualitative data were accumulated by in-depth interview and private documents collection. We analyzed the raw data following the Mandelbaum's conceptual frame ; dimension of life, turning point and adaptation. In analysis of the dimension of life, home, religion and occupation were represented as main thems. Home was interpreted as the reconstruction of existential field that assumes their fault and others. Religion was interpreted as the phenomenological field that develops their potentiality and peculiarity. Occupation was interpreted as the restraining means aganist returning to prostitution. In analysis of the turning point, we found a common theme : dis empowering the discourse power by body-politics. In analysis of the adaptation, we found three propositions as fellows: 1) "Living with stigma internalized by themselves" 2) "Living as anonymous being and absconding" 3) Expunging the past disgrace through shifting of social status. Based on the above results we proposed practical approaches for them.

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.5
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• pp.257-263
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• 2022

Active stabilizers use signals such as steering angle, yaw rate, and lateral acceleration to vary the roll stiffness of the front and rear suspension depending on the vehicle's driving conditions, and are attracting attention as RSC (Roll Stability Control) system that suppresses roll when turning and improves ride comfort when going straight. Various studies have been conducted in relation to active stabilizer bars and RSC systems. However, accurate modeling of passive stabilizer model and active stabilizer model and vehicle dynamics analysis result verification are insufficient, and performance result analysis related to vehicle roll angle estimation and electric motor control is insufficient. Therefore, in this study, an accurate vehicle dynamics model was constructed by measuring the passive/active stabilizer bar model and component parameters. Based on this, the analysis result with high reliability was derived by comparing the roll angle estimation algorithm based on the lateral acceleration and suspension of the vehicle with the actual vehicle driving test result. In addition, it was intended to accurately analyze the motor torque characteristics and roll reduction effects of the electric motor-driven RSC system.

• Geomechanics and Engineering
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• v.20 no.5
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• pp.411-420
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• 2020

Numbers fitting-curve equations have been proposed to predict soil-water retention curve (SWRC) whose parameters have no definitude physical meaning. And these methods with precondition of measuring SWRC data is time-consuming. A simplified directly method to estimate SWRC without parameters obtained by fitting-curve is proposed. Firstly, the total SWRC can be discretized into linear segments respectively. Every segment can be represented by linear formulation and every turning point can be determined by the pore-size distribution (PSD) of Mercury Intrusion Porosimetry (MIP) tests. The pore diameters governing the air-entry condition (AEC) and residual condition (RC) can be determined by the PSDs of MIP test. The PSD changes significantly during drying in SWR test, so the determination of AEC and RC should use the PSD under corresponding suction conditions. Every parameter in proposed equations can be determined directly by PSD without curve-fitting procedure and has definitude physical meaning. The proposed equations give a good estimation of both unimodal and bimodal SWRCs.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.125-134
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• 2003

In this study, Mooney-Rivlin 1st model and Mooney-Rivlin 3rd model are adopted as strain energy density functions of the rubber compounds of a radial tire. It is shown that the FE analysis using Mooney-Rivlin models for rubber compounds may provide good approximations by employing the appropriate strain range of experimental stress-strain data in a way to describe the stress-strain relationship accurately. Especially, Mooney-Rivlin 3rd model gives an accurate stress-strain relationship regardless of the fitting strain range used within the strain of 100%. The static nonlinear FE analysis of a tire inflation is performed by employing an axisymmetric model, which shows that the outside shapes of the tire before and after inflating the tire agree well with those of the real tire. Additionally, the deformations at crown center and turning point on sidewall, distribution of belt cord force, interlaminar shear strain are predicted in terms of variation of belt cord angle which is known as the most influential factor in inflation behavior of a tire.