스마트폰과 이동형 디바이스에 기반한 지능형 가정용 로봇 구현

양우철,김하종,박용진,유정호,임상글,이상준,Yang, Woocheol,Kim, Hajong,Park, Yongjin,Yu, Jeongho,Lim, Sanggul,Lee, Sangjun 한국전기전자학회 2013 전기전자학회논문지 Vol.17 No.4

IT 기술이 발전함에 따라 로봇은 다양한 부분에서 필요성을 인정받고 있다. 최근 산업용 로봇에만 집중되었던 로봇 시장은 일상생활에서도 사용할 수 있는 가정용 로봇까지 시장이 확대되고 있으며, 실제로 청소로봇이나 방범로봇과 같은 가정용 로봇이 개발되어 판매되고 있는 상태이다. 대부분의 가정용 로봇은 높은 가격에도 불구하고 기능이 제한적이며, 실제 로봇으로서 지능적인 부분은 자동청소 기능과 같이 사용자와의 소통이 없는 단순한 수준이다. 본 논문은 이동형 디바이스와 음성제어 및 각종 서비스를 제공하기 위한 스마트폰이 결합된 형태의 지능적인 가정용 로봇을 제안한다. As IT technology advances, the need for robots in various areas has been recognized. Robots that focused on the industrial market have been extended to household robots in everyday life. In fact, cleaning robots and security robots have been developed and sold. Most home robots, in spite of high price, their functions are limited. In this paper, we propose the intelligent home robot which is based on smartphones and moving devices to provide various services and voice control.

자외선 광여기 전자현미경을 이용한 Si 표면 위에 Ge 나노구조의 성장 동역학에 관한 실시간 연구

양우철,조우성,M. Himmerlich,R.J. Nemanich 한국진공학회 2007 Applied Science and Convergence Technology Vol.16 No.2

The evolution dynamics of nanoscale Ge islands on both Si (001) and (113) surfaces is explored using ultraviolet photoelectron emission microscopy (UV-PEEM). Real-time monitoring of the in-situ growth of the Ge island structures can allow us to study the variation of the size, the shape and the density of the nanostructures. For Ge depositions greater than ~ 4 monolayer (ML) with a growth rate of ~0.4 ML/min at temperatures of 450–550℃, we observed island nucleation on both surfaces indicating the transition from strained layer to island structure. During continuous deposition the circular islands grew larger via ripening processes. AFM measurements showed that the islands grown on Si (001) were dome-shaped while the islands on Si (113) were multiple-side faceted with flat tops of (113)-orientation. In contrast, for Ge deposition with a lower growth rate of ~0.15 ML/min on Si(113), we observed the shape transition from circular into elongated island structures. The elongated islands grew longer along the [33] during continuous Ge deposition. The shape evolution of the islands is discussed in terms of strain relaxation and kinetic effects. 자외선 광여기 전자현미경 (Ultraviolet - Photoelectron Emission Microscopy: UV-PEEM)을 이용하여 Si (001)과 (113) 표면에 Ge을 증착하면서 실시간으로 나노구조의 형성과 크기 및 형태 변화 과정을 조사하였다. Ge은 PEEM에 부착된 e-beam 증착기를 이용하여 450-550oC 온도에서 in situ로 증착하면서 표면의 변화를 PEEM으로 관찰하였다. Ge을 ~ 0.4 ML/min의 증착율로 ~ 4 ML 이상 두께로 증착했을 때, 두 Si 표면에서 Ge의 균일한 변형층(strained layer) 위에 island 구조가 형성되었다. 초기에 형성된 원형 모양의 island는 연속적인 Ge 증착에 따라, ripening 과정에 의해 크기가 점차 성장되었고 밀도는 감소하였으나, 형태는 원형 모양을 유지하였다. 시료 성장 후 공기 중 AFM 측정 결과, Si(001) 표면에는 dome 형태의 Ge island가 Si(113) 표면에는 윗면이 평판하고 다면의 옆면을 지닌 island 구조가 형성됨이 확인되었다. 반면에 ~0.15 ML/min의 낮은 증착율로 Ge을 증착했을 때, Si(113) 표면에서 원형의 Ge island가 길죽한(elongated) 형태의 나노선 구조로 변형됨이 관찰되었다. 또한, 계속적인 Ge 증착 두께를 증가시킴에 따라 표면에는 새로운 island가 형성되지 않고, 기존의 island들이 점차 길이 방향으로 크기가 증가하면서 [33] 방향으로 배열하였다. 이와 같은 Ge 나노구조의 형성과 형태 변화는 나노구조 형성과정에서 변형이완(strain relaxation)과 가원자(adatom)의 표면 동역학적 효과와 깊은 관련이 있는 것으로 분석된다.

Coarsening Dynamics of Nanoscale Ti-Silicide Islands on Si Surfaces

양우철,Matt Zeman,네마니치 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.3

The late-stage coarsening dynamics of nanoscale Ti-silicide (TiSi$_2$) islands on Si surfaces is explored in ultra high vacuum (UHV) by using ultraviolet photoelectron emission microscopy (UV-PEEM). The UV-PEEM is employed for real-time, {\it in-situ} monitoring of the nanostructure dynamics and evolution at high temperatures. Continuous annealing at $\sim$1150 $^\circ$C leads to an increase in the size of the initially nucleated silicide islands and to a reduction in the number density. By monitoring the relative position and the size of individual islands, we find that islands grow through Ostwald ripening and attractive migration and coalescence (AMC). The AMC is a new coarsening process where nearby islands are observed to migrate directly towards each other and subsequently coalesce. This process has been attributed to a growth-decay flow of the island edges driven by a non-uniform chemical potential around the islands. The non-uniform chemical potential results from a varying adatom surface concentration induced by local variations in size, number, and location of the neighboring islands. Significant shape distortions of the coarsening islands, migration of each island towards the center of mass of a group of islands, and screening of attractive migration of islands with a continuous Ti flux support our suggested model for the AMC mechanism. The mass exchange between the coarsening TiSi$_2$ islands in the AMC process is explained in terms of a Ti adatom surface-diffusion-limited process.

Determination of Cell Differentiation by Probing Cell Membrane Stiffness

권상우,양우철 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.4

Force spectroscopy as a function in atomic force microscopy (AFM) allows us to quantitatively explore the mechanical properties of individual bio cells. In this study, we investigated the variation in membrane stiffness of human neuroblastoma SH-SY5Y cells (SH-cells) and human bone marrow mesenchymal stem cells (H-BMMSCs). First, the correlation of the stiffness of cell membrane with the degree of the cell’s differentiation was observed by using force spectroscopy. The stiffnesses of the non-differentiated, the partially differentiated, and the fully neuronal differentiated SH-cells were found to be 0.7044 ± 0.0372 nN/nm, 0.5976 ± 0.0114 nN/nm, and 0.4989 ± 0.0538 nN/nm, respectively. These values indicated that the stiffness of the fully neuronal differentiated cells was softer than that of the non-differentiated ones. Next, this method was applied to determine the differentiation of the H-BMMSCs into neural cells. We found that the stiffness of the H-BMMSCs cultured in neural induction media was 29.81% smaller than that of the non-differentiated cells. The neural differentiation of the H-BMMSCs was confirmed by using a Western blot analysis. The change in the elasticity of the differentiated cells could be explained in terms of morphological and biochemical modifications of the membrane during the differentiation process. Our study demonstrated that probing the variation in the stiffness of the cell membrane is a fruitful method to determine the cell’s differentiation.

원자간력현미경(AFM)을 활용한 SH-SY5Y Neuroblastoma 세포의 분화 전후 세포막의 Stiffness 변화 연구

권상우,양우철,전광덕,이지은,이희수,정진권,홍현민,이정민,최푸름,장주희,최윤경,전송희 한국진공학회 2013 한국진공학회 학술발표회초록집 Vol.2013 No.2

Force Spectroscopy of Membrane Hardness of SH-SY5Y Neuroblastoma Cells Before and After Differentiation

권상우,양우철,최윤경,박정극 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.10

Atomic force microscopy (AFM) is utilized in many studies for measuring the structure and thephysical characteristics of soft and bio materials. In particular, the force spectroscopy function inthe AFM system allows us to explore the mechanical properties of bio cells. In this study, we probethe variation in the membrane hardness of human neuroblastoma SH-SY5Y cells (SH-cells) beforeand after differentiation by using force spectroscopy. The SH-cell, which is usually differentiatedby using a chemical treatment with retinoic acid (RA), is a neuronal cell line employed widely asan in-vitro model for neuroscience research. In force spectroscopy, the force-distance curves areobtained from both the original and the RA-treated cells while the AFM tip approaches and pusheson the cell membranes. The slope deduced from linear region in the force-distance curve is thespring constant and corresponds to the hardness of the cell membrane. The spring constant ofthe RA-treated cells (0.597 ± 0.010 nN/nm) was smaller than that of the original cells (0.794 ±0.010 nN/nm), reflecting a hardness decrease in the cells differentiated with the RA treatments. The results clearly demonstrated that the differentiated cells are softer than the original cells. Thechange in the elasticity of the differentiated cells might be caused by morphological modificationduring differentiation process. We suggest that force spectroscopy can be employed as a novelmethod to determine the degree of differentiation of stem cells into various functional cells.

Evolution dynamics of Ge nanostructures on Si surfaces

조우성,양우철,R.J. Nemanich 한국진공학회 2007 한국진공학회 학술발표회초록집 Vol.16 No.1

원자간력현미경(AFM)을 이용한 줄기세포의 신경세포로 분화 인지에 관한 연구

권상우,양우철,전송희,유보영,최윤경 한국진공학회 2012 한국진공학회 학술발표회초록집 Vol.2012 No.2

Selective Growth of Au Nanoparticles on PZT Substrates by Using a Photochemical Reaction

김정훈,양우철 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.10

We report the surface distribution of Au nanoparticles (NPs) grown on polarity-patterned ferroelectrics by using photochemical-reaction deposition. Polycrystalline lead zirconate titanate (PZT) was used as a ferroelectric substrate. The local polarization orientation on the surface was patterned by using atomic force microscopy (AFM). The Au NPs were grown by ultraviolet (UV) light exposure of the polarity-patterned PZT substrates while immersed in Au salt solutions. The wavelength dependence of the deposition of the NPs was investigated using UV band pass filters. The dimensions and the surface distribution of the NPs were measured by using AFM. For UV light without a filter, more NPs were formed on the +z polarity region than on the other regions. However, for UV light with wavelengths of 315 nm and 365 nm, we observed the selective deposition of NPs on +z polar domains. The NPs on the +z polar domains were denser and larger than those on the other non-polar regions. The average size of the NPs was ∼30 nm and the number density was ∼22/μm². In addition, the electron affinity of the PZT was found to be 3.0 eV from scanning Kelvin probe microscopy measurements of the PZT film surface with the deposition of Au NPs. This study suggests the possibility of controlling the sizes and the positions of Au NPs on a surface by optimizing the UV wavelength and polarity patterning of the ferroelectrics.

A dual-functional flexible sensor based on defects-free Co-doped ZnO nanorods decorated with CoO clusters towards pH and glucose monitoring of fruit juices and human fluids

Hilal Muhammad,양우철 나노기술연구협의회 2022 Nano Convergence Vol.9 No.14

Herein, ZnO nanorods were doped with Co and decorated with CoO clusters through an in situ technique to create a CoO/Co-doped ZnO (CO/CZO) heterostructure at low temperatures (150 °C) on a flexible PET substrate. In the CO/CZO heterostructure, the Co dopant has a low energy barrier to substitute Zn atoms and adsorb over oxygen atoms and their vacancies. Therefore, it decreased the charge density (ND = 2.64 × 1019 cm−3) on non-active sites of ZnO and lowered the charge transfer resistance (317 Ω) at Co-doped-ZnO/electrolyte interface by suppressing the native defects and reducing the Schottky barrier height (− 0.35 eV), respectively. Furthermore, CoO clusters induced a p-n heterostructure with Co-doped ZnO, prevented corrosion, increased the active sites for analyte absorption, and increased the ultimate tensile strength (4.85 N m−2). These characteristics enabled the CO/CZO heterostructure to work as a highly sensitive, chemically stable, and flexible pH and glucose oxidation electrode. Therefore, CO/CZO heterostructure was explored for pH monitoring in human fluids and fruit juices, demonstrating a near-Nernst-limit pH sensitivity (52 mV/pH) and fast response time (19 s) in each human fluid and fruit juice. Also, it demonstrated high sensitivity (4656 µM mM−1 cm−2), low limit of detection (0.15 µM), a broad linear range (0.04 mM to 8.85 mM) and good anti-interference capacity towards glucose-sensing. Moreover, it demonstrated excellent flexibility performances, retained 53% and 69% sensitivity of the initial value for pH and glucose sensors, respectively, after 500 bending, stretching, and warping cycles.