• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.918-921
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• 2000

Micro-machining, one of the non-traditional machining techniques, can achieve a wanted shape of the surface using metal dissolution with electrochemical reaction and can be applied to the metal such as high tension, heat resistance and hardened steel. The workpiece dissolves when it is positioned close to the tool electrode in electrolyte and the current is applied. Traditional machining has been used in the industries such as cutting, deburring, drilling and shaping. The aim of this work is to develop Micro-machining techniques for micro shape by establishing appropriate machining parameters of micro-machining

• Restorative Dentistry and Endodontics
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• 제45권3호
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• pp.30.1-30.11
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• 2020

Objectives: This micro-computed tomographic (CT) study aimed to compare the shaping abilities of ProTaper Next (PTN), One Shape (OS), and One Curve (OC) files in 3-dimensionally (3D)-printed mandibular molars. Materials and Methods: In order to ensure standardization, 3D-printed mandibular molars with a consistent mesiobuccal canal curvature (45°) were used in the present study (n = 18). Specimens were instrumented with the OC, OS, or PTN files. The teeth were scanned pre- and post-instrumentation using micro-CT to detect changes of the canal volume and surface area, as well as to quantify transportation of the canals after instrumentation. Two-way analysis of variance was used for statistical comparisons. Results: No statistically significant differences were found between the OC and OS groups in the changes of the canal volume and surface area before and after instrumentation (p > 0.05). The OC files showed significantly less transportation than the OS or PTN systems for the apical section (p < 0.05). In a comparison of the systems, similar values were found at the coronal and middle levels, without any significant differences (p > 0.05). Conclusions: These 3 instrumentation systems showed similar shaping abilities, although the OC file achieved a lesser extent of transportation in the apical zone than the OS and PTN files. All 3 file systems were confirmed to be safe for use in mandibular mesial canals.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권11호
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• pp.654-659
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• 2005

An improved power supply for APD(Avalanche Photo Diode) with a received optical power monitoring circuit allows the received optical power increase temporary without of the degradation of the electrical signal. For the cost reduction and simple fabrication, an improved power supply has been proposed that it was designed for driving a APD as a receiving device of a wireless optical transmission system. It was demonstrated that it was possible to improve a dynamic range by compensating the temperature coefficient of the APD up to 1.0 V/$^{\circ}C$ through the power supply. Also, for an efficient transmission at the receiver end, a simple structure of a single cylindrical micro-lens configuration was used in conjunction with the laser diode to partially compensate a laser beam ellipticity. For this purpose, an astigmatism introduced by the micro-lens is utilized for the additional compensation of the beam ellipticity at the receiver end. In this paper, it is demonstrated that an efficient beam shaping is realized by using the proposed configuration consisting of the single lens attached to the laser diode.

• 한국기계가공학회지
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• 제9권4호
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• pp.1-7
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• 2010

Recently optical and electric and electronic forms in the field of ultra fine patterns has been used extensively, and techniques of the optical parts are required that can precision-machine this micro-patterns such as V or R-shaped micro-groove patterns. In this study, V and R type, shaping the way micro groove brass machining process to characterize the material feed rate and cutting depth and the V and R as a variable brother, using two kinds of diamond tools for each picture shape and surface roughness caused by conditions such as chips, processed through the analysis of effects of geometry and analysis such as precision machining.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.637-638
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• 2010

• 한국기계가공학회지
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• 제13권6호
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• pp.119-126
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• 2014

Micro-holes of conductive ceramic are required in micro structures. Micro-electrical discharge machining (Micro-EDM) is an effective machining method since EDM is as process for shaping hard metals and complex-shaped holes by spark erosion in all kinds of electro-conductive materials. However, as the depth of micro hole increases, the machining condition becomes more unstable due to inefficient removal of debris between the electrode and the workpiece. In this paper, micro-EDM was performed to evaluate machining characteristic such as electrode wear, machining time, taper angle, radial clearance with varying voltage and ultrasonic vibration on 10 vol.% Carbon-nanotube reinforced conductive $Al_2O_3$ composite fabricated by spark plasma sintering in previous research.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1265-1268
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• 2005

Due to the increase of the need for reliable high density information storage devices, the demand for precise machining of the slider in HDD is rapidly growing. The present fabrication process of slider bears some serious problems such as low yield ratio in mass production, which is mainly caused by inefficient machining processes in shaping camber and crown on the slider. In order to increase slider yield ratio in HDD, a new systematic machining process is proposed and developed in this work. This new machining process includes the use of magnetorheological (MR) fluid, a smart polishing material generally used for ultra-fine surface finishing of micro structures. It is shown that the process proposed in this work enables to make camber and crown pattern in the scale of few tens of nanometers. Experiment results shows that the MR polishing can be also used for shaping process of micro structures.

• Advances in nano research
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• 제16권6호
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• pp.615-622
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• 2024

This study investigates the impact of educational management on the performance of scholars in the field of nano/micro-level composites. The objective is to understand how effective management strategies can enhance the academic achievements and research outcomes of students specializing in this advanced area of materials science. Through a combination of qualitative and quantitative methodologies, data was collected from various educational institutions renowned for their programs in nano/micro-level composites. Our results indicate that tailored educational management practices significantly improve student performance. Key strategies identified include personalized mentorship programs, interdisciplinary collaboration opportunities, and access to state-of-the-art laboratory facilities. Institutions that implemented these practices observed a marked increase in the quality and quantity of research outputs, higher student satisfaction rates, and improved post-graduation employment prospects in relevant industries. Furthermore, the study highlights the importance of continuous professional development for educators to stay abreast of the latest advancements in nano/micro-level composites. By fostering an environment of innovation and support, educational management can play a crucial role in shaping the next generation of researchers and professionals in this cutting-edge field. These findings underscore the necessity of strategic educational management in optimizing the academic and professional trajectories of scholars in nano/micro-level composites, ultimately contributing to advancements in technology and industry applications.

• 산학경영연구
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• 제2권
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• pp.141-169
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• 1989

Most of the theories of collective bargaining outcomes start with a set of economic variables. The economic constraints, pressures, and incentives influence the bargaining power relationship between labor union and employer. In this paper, the critical macro and micro economic variables that need to be considered in analyzing the economic context of collective bargaining power relationship is outlined. The focus is on the role that economic forces play in shaping the results of bargaining, that is the outcome of negotiations. In this study, the elasticity of the demand for labor is introduced as one of the most important economic aspects that influence bargaining power. Unions will be most successful in increasing wages when they enjoy an inelastic demand for labor. If the demand for labor is not naturally inelastic, some institutional arrangement for "taking wages out of competition" must be sought. Inflation, business cycle, and income policy are influential in shaping both parties' goals and expectations as well. In addition to the analysis of the economic variables, the nature of power is diagonized with some introductory notions about its care and feeding before proceeding to the details of the above issues.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.987-992
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• 1997

Burrs always come out with the machining of ducterial with small size. Though the size of burrs is small, burrs dominate deterioration of the accuracy of the micro grooves. So the burr generation model especially side burr generation model was investigated to predict the size of the burrs at the given cutting conditions. The side shear plane is introduced to build the burr generation model and the width of side shear plane nomalized with cutting depth is defined with the shear angle. From the theoretical observation, the width of side shear plane can vary up 40% of the cutting depth. To determine the size of burr and stiffness, single groovings were carried out and it was found that there exist a critical depth of cut that the size or stiffness of the burr vary.