광 마우스 기반 주행 표면 특성 시험 장치의 분석 및 구현

김성복(Sungbok Kim) 제어로봇시스템학회 2016 제어·로봇·시스템학회 논문지 Vol.22 No.7

This paper presents the analysis and implementation of traveling surface characteristics test equipment using optical mice in connection with the velocity estimation of a mobile robot equipped with optical mice. In the traveling surface characteristics test equipment, a traveling surface sample is made to rotate toward stationary optical mice instead of a mobile robot equipped with optical mice moving over a traveling surface. First, the conceptual design and operational principle of the traveling surface characteristics test equipment is explained. Second, the velocity kinematics of the traveling surface characteristics test equipment is formulated; based on this, the parameter setting of the traveling surface characteristics test equipment is described. Third, the implementation of the traveling surface characteristics test equipment is described in detail, including the mechanical design and construction and the hardware and software development. Fourth, using the prototype of the traveling surface characteristics test equipment, the experimental results of the statistical parameter extraction for different traveling surface samples are given. Finally, some potential usages of the traveling surface characteristics test equipment are discussed.

SURFACE ANALYSES OF TITANIUM SUBSTRATE MODIFIED BY ANODIZATION AND NANOSCALE Ca-P DEPOSITION

Lee, Joung-Min,Kim, Chang-Whe,Lim, Young-Jun,Kim, Myung-Joo The Korean Academy of Prosthodonitics 2007 대한치과보철학회지 Vol.45 No.6

Statement of problem. Nano-scale calcium-phosphate coating on the anodizing titanium surface using ion beam-assisted deposition (IBAD) has been recently introduced to improve the early osseointegration. However, not much is known about their surface characteristics that have influence on tissue-implant interaction. Purpose. This study was aimed to investigate microtopography, surface roughness, surface composition, and wettability of the titanium surface modified by the anodic oxidation and calcium phosphate coating using IBAD. Material and methods. Commercially pure titanium disks were used as substrates. The experiment was composed of four groups. Group MA surfaces represented machined surface. Group AN was anodized surface. Group CaP/AN was anodic oxidized and calcium phosphate coated surfaces. Group SLA surfaces were sandblasted and acid etched surfaces. The prepared titanium discs were examined as follows. The surface morphology of the discs was examined using SEM. The surface roughness was measured by a confocal laser scanning microscope. Phase components were analyzed using thin-film x-ray diffraction. Wettability analyses were performed by contact angle measurement with distilled water, formamide, bromonaphtalene and surface free energy calculation. Results. (1) The four groups showed specific microtopography respectively. Anodized and calcium phosphate coated specimens showed multiple micropores and tiny homogeneously distributed crystalline particles. (2) The order of surface roughness values were, from the lowest to the highest, machined group, anodized group, anodized and calcium phosphate deposited group, and sandblasted and acid etched group. (3) Anodized and calcium phosphate deposited group was found to have titanium and titanium anatase oxides and exhibited calcium phosphorous crystalline structures. (4) Surface wettability was increased in the order of calcium phosphate deposited group, machined group, anodized group, sandblasted and acid etched group. Conclusion. After ion beam-assisted deposition on anodized titanium, the microporous structure remained on the surface and many small calcium phosphorous crystals were formed on the porous surface. Nanoscale calcium phosphorous deposition induced roughness on the microporous surface but hydrophobicity was increased.

서비스 팀에서 다양성 관리에 관한 연구: 팀장의 과업수행 역량의 조절효과를 중심으로

김보영,박오수 리더십학회 2011 리더십연구 Vol.2 No.4

Managing diversity in work group is one of the most important, at the same time, difficult challenges in current organizations. However, few studies have been examined diversity management that controls the effect of diversity on team characteristics. The present study investigates diversity management by examining team leader’s competence which moderates the relationship between team member’s diversity and team characteristics. Specifically, this study has two purposes. First, we examine the relationship between different types of diversity (i.e., surface level and deep level diversity) and team charactersitics (flexibility, support climate, and communication). Second, we suggest team leader’s competence as a moderator, which manages a negative or positive impact of diversity on team characteristics. As a main effect of diveirsy, we expect that surface-level diversity (age difference and education level difference) has a positive effect on team characteristics through the elaboration process, and that deep-level diversity (organizational commitment difference and team satisfaction difference) has a negative effect on team characteristics through the categoration process. As a moderating effect of team leader’s competence, we expect that the positive effect of surface-level diversity on team characteristics will be stronger and the negative effect of deep-level diversity on team characteristics will be weaker when team leadership is high than when team leadership is low. For examining hypotheses, data were collected from 130 service teams in firm located in South Korea. The results showed hypothesis concering main effects of two forms of diversity were partially supported. Education level diversity had positive effects on three team characteristics. Team satisfaction diversity had negative effects on three characteristics. Interaction effects between team leader’s competence and education level diversity on supportive climate and communication were significant respectively. In addition, interaction effects between team leader’s competence and team satisfaction diversity on three team characterstics were significant. However, interaction patterns between team leader’s competence and each form of diversity on team characteristics were different respectively. Our findings suggest that team leader is able to manage effects of surface- and deep-level diversity on team characterists. The results of our study contribute to extend the understanding of diversity management. 본 연구의 목적은 두 가지 형태의 다양성, 즉 표면적 다양성(surface-level diversity)과 내면적 다양성(deep-level diversity)이 주요한 팀 특징들에 미치는영향을 살펴보고, 팀 특징들에 미치는 다양성의 영향을 조절해주는 변수로서 팀장의 과업수행 역량의 역할을 검증하는 것이다. 본 연구에서 팀장의 과업수행역량은 팀장이 팀의 구성원들로 하여금 팀 목표설정, 업무할당, 과업진행 및 성과달성 등의 팀 프로세스를 원활하게 수행하도록 하는 리더의 역할을 얼마나 충실히 수행하였는지를 측정하였다. 총 130개의 서비스 팀을 대상으로 실시한 실증연구결과는 다음과 같다. 첫째, 표면적 다양성인 교육수준의 차이는 팀 후원풍토와 의사소통에 긍정적 영향을, 내면적 다양성인 팀 만족도 차이는 세 가지 팀특징들에 모두 부정적 영향을 미치는 것으로 나타났다. 둘째, 팀장 역량이 다양성과 팀 특징들 간의 관계를 조절하는 것으로 검증되었다. 하지만 팀 특징들에영향을 미치는 팀장 역량의 표면적 다양성과 내면적 다양성과의 상호작용 패턴이 차이가 있음을 알 수 있었다. 본 연구의 시사점은 다음과 같다. 첫째, 팀 운영에 있어서 표면적 다양성과 내면적 다양성이 팀 특징들에 미치는 영향이 상이하게 나타날 수 있다는 점이다. 둘째, 팀 내 다양성이 팀의 성과를 촉진시킬 수있는 요소가 아니라 분열을 일으키는 문제적 요소로 발견된다면 팀장의 과업수행 역량을 통하여 다양성의 부정적 효과를 감소시킬 수 있음을 본 연구 결과를통해 검증하였다.

FTS를 이용한 나노표면개질공정의 공정변화와 소재에 따른 표면특성

김미루(Mi Ru Kim),이득우(Deug Woo Lee),이승준(Seung Jun Lee),Li Liang,김종만(Jong Man Kim),장남수(Nam-Su Jang) 한국생산제조학회 2015 한국생산제조학회지 Vol.24 No.6

A treatment for improving the characteristics of a surface is very important in increasing the life of machine parts. Many studies have been carried out on the surface characteristics after such treatments. For enhanced eco-technology, an alternative to a conventional chemical surface treatment process is essential. Ultrasonic nano-crystal surface modification (UNSM) technology is a physical environmentally friendly surface treatment method. This technology was developed in domestic and currently being used. As the mechanism of UNSM technology, a ball tip attached to an ultrasonic vibration device strikes the metal surface at nearly 20,000 times per second. The resulting modified surface layer improves the surface characteristics. This paper describes a self-developed fast tool servo system applied to the UNSM process as a vibration module within a high-frequency bandwidth. After describing the surface modification process based on the material and process changes, the surface characteristics are compared.

Experimental Study on the Hydrophilic Porous Film Coating for Evaporative Cooling Enhancement

Lee, Dae-Young,Lee, Jae-Wan,Kang, Byung-Ha The Society of Air-Conditioning and Refrigerating 2005 International Journal Of Air-Conditioning and Refr Vol.13 No.2

Falling film heat transfer has been widely used in many applications in which heat and mass transfer occur simultaneously, such as evaporative coolers, cooling towers, absorption chillers, etc. In such cases, it is desirable that the falling film spreads widely on the surface to form a thin liquid film to enlarge contact surface and to reduce the thermal resistance across the film and/or the flow resistance to the vapor stream over the film. In this respect, hydrophilic treatment of the surface has been tried to improve the surface wettability by decreasing the contact angle between the liquid and the surface. However, the hydrophilic treatment was found not very effective to increase the surface wettedness of inclined surfaces, since the liquid flow forms rivulet patterns instead of a thin film as it flows down the inclined surface and accelerates gradually by the gravity. In this work, a novel method is suggested to improve the surface wettedness enormously. In this work, the surface is treated to have a thin hydrophilic porous layer on the surface. With this treatment, the liquid can spread widely on the surface by the capillary force resulting from the porous structure. In addition to this, the liquid can be held within the porous structure to improve surface wettedness regardless of the surface inclination. The experiment on the evaporative cooling of inclined surfaces has been conducted to verify the effectiveness of the surface treatment. It is measured that the latent heat transfer increases almost by $80\%$ at the hydrophilic porous layer coated surface as compared with the untreated surface.

다공물질 표면처리가 경사판의 증발냉각에 미치는 영향에 관한 실험적 연구

이대영,이재완,강병하 대한설비공학회 2005 설비공학 논문집 Vol.17 No.1

Falling film heat transfer has been widely used in many applications in which heat and mass transfer occur simultaneously, such as evaporative coolers, cooling towers, absorption chillers, etc. In such cases, it is desirable that the falling film spreads widely on the surface forming thin liquid film to enlarge contact surface and to reduce the thermal resistance across the film and/or the flow resistance to the vapor stream over the film. In this work, the surface is treated to have thin porous layer on the surface. With this treatment, the liquid can be spread widely on the surface by the capillary force resulting from the porous structure. In addition to this, the liquid can be held within the porous structure to improve surface wettedness regardless of the surface inclination. The experiment on the evaporative cooling of an inclined surface has been conducted to verify the effectiveness of the surface treatment. It is measured that the evaporative heat transfer increases about 50% by the porous layer treatment as compared with that from orignal bare surfaces.

표면 특성에 따른 비등열전달 현상

김진섭(Jinsub Kim),이정호(Jungho Lee) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12

Surface characteristics such as surface roughness and surface wettability are the most important factors that affect heat transfer coefficient (HTC) and critical heat flux (CHF) in pool boiling. Effect of surface characteristics on pool boiling heat transfer of water was investigated using various surfaces having different roughness and different wettability. Surface roughness (R<SUB>a</SUB>) on the copper surfaces having moderate wettability (θ = 65°) was varied from 0.041 μm to 2.36 μm. It is verified that both HTC and CHF increase with increasing surface roughness. Three surfaces having similar surface roughness (R<SUB>a</SUB> ~ 0.11 μm) and different contact angles of 12° (superhydrophilic), 65° (moderate), and 122° (hydrophobic) were examined. While HTC increases with contact angle increase at low heat flux, CHF on the hydrophobic surface was merely 55 kW/m², which is over 20 times smaller than those on hydrophilic surfaces.

Influence of Surface Roughness on Friction and Wear Characteristics of SUS 321 for Hydraulic Cylinder Parts Application

이성준,장용훈,김창래 한국트라이볼로지학회 2023 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.39 No.6

This paper presents a comprehensive analysis of the impact of surface roughness on the friction and wear properties of SUS 321, an austenitic stainless steel variant produced using the laser powder bed fusion (LPBF) technique, which is a prevalent additive manufacturing method. After the LPBF fabrication, the specimens go a heat treatment process aimed at alleviating residual stress. Subsequently, they are polished extensively to achieve a refined and smooth surface. To deliberately introduce controlled variations in surface roughness, an etching process is employed. This multi-step method encompassed primary etching in a 3M hydrochloric acid solution, followed by secondary etching in a 35 wt% ferric chloride solution, with varying durations applied to different specimens. A comprehensive evaluation of the surface characteristics ensued, employing precise techniques such as surface roughness measurements and meticulous assessments of water droplet contact angles. Following the surface treatment procedures, a series of friction tests are performed to explore the tribological behavior of the etched specimens. This in-depth investigation reached its peak by revealing valuable insights. It clarified a strong correlation between intentionally altered surface roughness, achieved through etching processes, and the resulting tribological performance of LPBF-fabricated SUS 321 stainless steel. This significantly advances our grasp of material behavior in tribological applications.

Histologic evaluation and removal torque analysis of nano- and microtreated titanium implants in the dogs

Ahn, Seok,Vang, Mong-Sook,Yang, Hong-So,Park, Sang-Won,Lim, Hyun-Pil 대한치과보철학회 2009 The Journal of Advanced Prosthodontics Vol.1 No.2

STATEMENT OF PROBLEM. A number of studies about the nano-treated surfaces of implants have been conducting along with micro-treated surfaces of implants. PURPOSE. The purpose of this study was to get information for the clinical use of nano-treated surfaces compared with micro-treated surfaces by measuring removal torque and analyzing histological characteristics after the placement of various surface-treated implants on femurs of dogs. MATERIAL AND METHODS. Machined surface implants were used as a control group. 4 nano-treated surface implants and 3 micro-treated surface implants [resorbable blast media surface (RBM), sandblast and acid-etched surface (SAE), anodized RBM surface] were used as experimental groups. Removal torque values of implants were measured respectively and the histological analyses were conducted on both 4weeks and 8weeks after implant surgery. The surfaces of removed implants after measuring removal torque values were observed by scanning electron microscopy (SEM) at 8 weeks. RESULTS. 1. Removal torque values of the nano-treated groups were lower than those of micro-treated groups. 2. Removal torque values were similar in the anodized RBM surface groups. 3. On the histological views, there was much of bone formation at 8 weeks, but there was no difference between 4 and 8 weeks, and between the types of implant surfaces as well. CONCLUSION. it is suggested that implant topography is more effective in removal torque test than surface chemistry. To get better clinical result, further studies should be fulfilled on the combined effect of surface topography and chemistry for the implant surface treatments.

광 마우스 기반 주행 표면 특성 추출 장치의 실험 결과

김성복,김현빈,임근형,김형진 제어로봇시스템학회 2013 제어로봇시스템학회 각 지부별 자료집 Vol.2013 No.12

This paper presents the experimental results for two different types of traveling surface samples using the optical mouse based traveling surface characteristics extraction equipment of our own design. One key to put into practice the optical mouse based mobile robot velocity estimation technique is the investigation of the changing patterns of the optical mouse velocity measurements according to a given traveling surface. In this paper, the traveling surface characteristics extraction equipment is proposed, in which a traveling surface sample is rotating with respect to an array of stationary optical mice, instead of a mobile robot equipped with optical mice traveling over a given surface. First, the conceptual design of the proposed traveling surface characteristics extraction equipment is explained, along with its prototype built in our lab. Then, for both wood and marvel traveling surface samples, the statistical parameters of the optical mouse velocity measurements are extracted, using our extraction equipment prototype.