뇌성마비 지체장애 아동을 위한 대체의사소통기기 설계, 제작 및 중재

김창걸,이근민,송병섭 대구대학교 특수교육재활과학연구소 2005 再活科學硏究 Vol.23 No.2

For the handicapped person who is in a difficulty of speech communication by cerebral palsy(CP), an augmentative and assistive communication (AAC) equipment was designed, implemented and applied. The AAC equipment was designed to generate recoded voice that is matched to the pressed word plate. A handicapped person by CP have been selected and after investigation of her disabled condition, the equipment was considered to be put on the knee of user who have to sit at a wheelchair. For the low power consumption, a PIC16F84 micro controller was used in the control module of the AAC and an IC record & play kit was used for the voice recording and generating the sound. The implemented equipment was tested by the selected disabled and it was verified that the AAC equipment have suitable performances as designed concept. 뇌성마비로 인하여 의사소통이 힘든 아동이 자신의 의사를 표현할 수 있도록 도와주기 위하여 원하는 단어판을 누를 경우 해당하는 음성을 소리로 발생시킴으로써 대화가 가능하도록 하는 대체의사소통기구를 설계, 제작하였다. 선정된 대상아동의 장애상태를 확인한 후 사용할 수 있는 왼쪽 손을 이용하여 포인팅 함으로써 자신의 의사를 전달할 수 있도록 하였으며, 발생하는 음성을 의미하는 그림이 그려진 단어판 스위치를 직접 입력할 수 있도록 함으로써 가정에서 원하는 대화를 가능하도록 설계하였다. 의사소통기기의 제어기는 PIC16F84를 이용하였고, 음성출력기는 20초 이내의 범위에서 직접 녹음할 수 있으며 저전력으로 동작하는 집적회로를 이용한 음성 녹음 및 출력기를 사용하였다. 기기제작 후 대상아동에게 사용함으로써 설계된 계획에 맞도록 의사소통기기가 양호하게 동작함을 확인하였다. 앞으로 이러한 기기의 성능개선을 실시할 경우 현재 외국에서 수입되고 있는 값비싼 의사소통기기를 대체할 수 있는 가능성을 확인하였다.

Indium이 도핑된 Si/CeO_2/Si 박막의 발광 현상

문병식,김종걸,양지훈,박종윤 성균관대학교 기초과학연구소 1998 論文集 Vol.49 No.-

Visible light with about 500 nm was observed from the indium doped Si/CeO_2/Si thin films at room temperature. CeO₂, indium, and silicon were in sequence deposited on the Si(111) substrate using electron beam evaporation. As the indium was increased the peak intensity of 500 nm was increased. After furnace annealing in nitrogen at 1100℃ the peak was observed at 400 nm. Secondary ion mass spectrometry(SIMS) showed the mixed layer of CeO₂, indium, and silicon. It seems that the peak around 500 nm would come from the mixed layer.

Al-고농도 Mg(≥7 wt.%) 합금의 β상 석출분해에 미치는 La 및 Mm 첨가의 효과

朴秀東,金秉杰 대한금속재료학회 2001 대한금속·재료학회지 Vol.39 No.12

In order to clarify the behavior of precipitation and dissolution in Al-Mg-(La, Mm) alloys with a high Mg content(x≥7 wt.%) in detail, the characteristic parameter of DVRC (Differentiated values of the ratio of electrical resistivity change) depending on temperature has been investigated at a slow heating rate (0.05 K/min). Since the value of DVRC is very sensitive to its microstructural change, it enables us to understand the precipitation and dissolution behavior of phases clearly and quantitatively. During the heating, the transformation process of precursor phase, such as G. P. zone, shown as a positive peak at low temperature region, was retarded and the precipitation of β phase was suppressed by La or Mm addition. And the homogeneous precipitation of β phase was also induced by the additive elements of La or Mm.

Anomalous Electric Conductivity for Insoluble SiO2/Pb Films Prepared by Sputtering

Kim, Byung Geol 대한금속재료학회(대한금속학회) 2000 METALS AND MATERIALS International Vol.6 No.3

Dual phase sputtered films of an insoluble SiO₂/Pb system were prepared by sputtering and their electric conductivity mechanisms were investigated. The microstructure of the sputtered films consisted of an amorphous SiO₂ phase and a crystalline fcc Pb phase. The homogeneous granular structure, where Pb particles of 5∼20 ㎚ in diameter were embedded homogeneously in a SiO₂ matrix, was observed in the Pb content of 64∼71 vol.%, and the inhomogeneous granular structure, where fine and coarse Pb particles coexisted, was observed in the Pb content of 78∼92 vol.%. Dissolution of Si or O into the Pb phase was not detected. The sputtered films showed a great diversity in TCR signs and inclinations according to Pb content. As Pb content decreased, the positive TCR slope decreased and changed into a negative TCR from Pb 64 vol.%. This is because as Pb content decreased, the percolation cluster composed of Pb particles, which makes metallic electric conductivity possible, diminished gradually, and electric channels disappeared finally, changing into other electric conductivity mechanisms induced from the tunneling effect of electrons. Sputtered films were conductors with high electric resistivity when they had homogeneous granular structures. This is probably due to the fabrication method, which makes atomic level control during film preparation possible. It seems that because the movement of electrons was obstructed by fine Pb particles dispersed in an insulator Si∼ matrix and lattice defects introduced during sputtering, the mean free path length of electron was reduced drastically. Also the significantly reduced cross section area in the links of channel where the contact regions of particles that form percolation clusters also generates high resistivity. The percolation limit for this system was Pb 67 vol.%. There was an inverse relationship between p_y, and TCR, which corresponds to Mooji's empirical rule, but TCR was still positive when ρ_(293)≥2μΩm at certain compositions. It seems that this result is also due to the unique hybrid microstructure of these films. The electric conductivity mechanism of sputtered f lms was investigated using the power law of percolation electric conductivity and a result of p=4.1 was obtained. A composite cell effective-medium theory was applied to explain this result, and it was found that the sputtered films consisted of composite cells(A and B type). This coincided well with the microstructures observed by TEM.

The Effect of Magnetic Field Annealing on the Texture of 2nd Recrystallization for a Deformed Fe-3.2%Si Steel Sheet

Byung Geol Kim,Su Dong Park,Shang Shu Kim 대한금속학회 2004 METALS AND MATERIALS International Vol.10 No.6

Anomalous Reheating Behavior of SiCp/Al Composite with High Volume Fraction Reinforcement

(Byung Geol Kim) 대한금속재료학회 ( 구 대한금속학회 ) 2001 METALS AND MATERIALS International Vol.7 No.3

The reheating behavior of 50 vol.% SiCp/Al squeeze casting composite was investigated at temperatures ranging from 600℃ to 900℃ using XRD and SEM techniques from the microstructural point of view. It was found that SiCp/Al composite could hold its original shape while being reheated at temperatures elevated even far above the melting temperature of pure Al. The high volume fraction of SiC reinforcement, which would restrict the fluidity of molten Al matrix and the reconfiguration of SiC particles during the reheating of SiCp/Al composite, was thought to be responsible for the “remelting resistance” of the SiCp/Al composite. The extent of the reaction between the SiC particles and molten Al was found to increase with increased reheating temperature. From the viewpoint of controlling the formation of aluminum carbide, reheating temperature either for recycling or for remelting processing of the SiCp/Al composite, a temperature lower than 750℃ would be better. Despite its being unfavorable to remelting or recycling processing, the remelting resistance of the SiCp/Al composite with high volume fraction reinforcement is attractive for thermal function and high temperature applications.

Up-Regulation of NAG-1 and p21 Genes by Sulforaphane

Byung-Geol Jeong(정병걸),Soon Young Kim(김순영),Kon Joo Lee(이건주),Jong-Sik Kim(김종식) 한국생명과학회 2012 생명과학회지 Vol.22 No.3

본 연구에서는 대장암 세포주 모델에서 브로콜리 유래 sulforaphane에 의한 항 성장 활성과 항암 단백질 NAG-1과 p21의 발현 및 발현 조절에 대해서 연구하였다. 그 결과, 처리한 sulforaphane의 농도가 증가됨에 따라 세포사멸이 증가되었고, 세포 생존율은 감소하였다. 또한, sulforaphane에 의한 항암 단백질 NAG-1과 p21의 발현증가를 농도별, 시간대별로 확인한 결과, 두 단백질 모두 sulforaphane 농도와 처리시간 의존적으로 발현이 증가됨을 확인하였다. Sulforaphane에 의한 NAG-1과 p21의 발현의 p53 의존성을 연구한 결과, p21의 발현은 p53에 의존적 이지만 NAG-1의 발현은 p53에 비 의존적인 것으로 생각된다. 또한, sulforaphane이 dietary histone deacetylase inhibitor로서 NAG-1의 발현을 증가시킬 가능성은 매우 미미한 것으로 생각된다. 전사조절인자인 ATF3의 발현을 sulforaphane을 시간대 별로 처리한 후 확인한 결과, 2시간째부터 발현이 증가되어 NAG-1의 발현 보다 먼저 증가됨을 확인하였다. 이러한 연구 결과는 sulforaphane의 항암 기능을 이해하는 새로운 기전을 제시해 줄 것으로 기대된다. We investigated the anti-proliferative activity of sulforaphane and expression changes of NAG-1 and p21 genes in response to sulforaphane treatment in human colorectal HCT116 cells. The results showed that sulforaphane decreased cell viabilities in a dose-dependent manner and induced expression of NAG-1 and p21 proteins in a dose-dependent and time-dependent manner. In addition, we found that NAG-1 expression by sulforaphane was not dependent on the presence of p53, whereas p21 expression was dependent on p53 presence. The results indicated that up-regulation of NAG-1 was not related with the activity of a dietary histone deacetylase inhibitor of sulforaphane. ATF3 induction was detected from 2 hr after sulforaphane treatment, indicating that ATF3 could be a transcription factor to up-regulate NAG-1 expression. The results of this study may help to increase our understanding of the molecular mechanism of anti-cancer activity mediated by sulforaphane in human colorectal cancer cells.

Anomalous Reheating Behavior of SiCp/Al Composite with High Volume Fraction Reinforcement

Kim, Byung Geol,Kim, Ick Jun,Dong, Shang Li 대한금속재료학회(대한금속학회) 2001 METALS AND MATERIALS International Vol.7 No.3

The repeating behavior of 50 vol.% SiCp/Al squeeze casting composite was investigated at temperatures ranging from 600℃ to 900℃ using XRD and SEM techniques from the microstructural point of view. It was found that SiCp/Al composite could hold its original shape while being repeated at temperatures elevated even far above the melting temperature of pure Al. The high volume fraction of SiC reinforcement, which would restrict the fluidity of molten Al matrix and the reconfiguration of SiC particles during the repeating of SiCp/Al composite, was thought to be responsible for the $quot;remelting resistance$quot; of the SiCp/Al composite. The extent of the reaction between the SiC particles and molten Al was found to increase with increased repeating temperature. From the viewpoint of controlling the formation of aluminum carbide, repeating temperature either for recycling or for remelting processing of the SiCp/Al composite, a temperature lower than 750℃ would be better. Despite its being unfavorable to remelting or recycling processing, the remelting resistance of the SiCp/Al composite with high volume fraction reinforcement is attractive for thermal function and high temperature applications.

GMR Effects in the Process of Decomposition of Co10Cu90 Ribbons

Kim, Byung Geol,Kim, Ick Jun,Lee, Hee Woong 대한금속재료학회(대한금속학회) 2001 METALS AND MATERIALS International Vol.7 No.3

The progress spinodal decomposition in aged Co_(10)Cu_(90) ribbons is closely correlated with giant magnetoresistance (GMR). In the phase decomposition, the MR ratio due to spin dependent scattering increases with the increase in the interface area in the constant wavelength regime. A maximum MR ratio of 8.1 % in 15 kOe is obtained in the Co_(10)Cu_(90) ribbon aged at 673 K for 166 h. By further aging, the MR ratio in high fields decreases with the increase of the wavelength, while the susceptibility of the MR ratio in low fields becomes larger due to the coarsening of ferromagnetic particles.

The Electrical Resistivity of a SiC_w/Al Alloy Composite with Temperature

Kim Byung-Geol,Dong Shang-Li,Park Su-Dong,Lee Hee-Woong Materials Research Society of Korea 2004 한국재료학회지 Vol.14 No.7

The electrical property of MMC is essentially important to some applications such as power transmission lines and cables, electronic and electrical components as well as electromagnetic shielding equipments. The behavior of electrical resistivity of $SiC_{w}/Al$ alloy composites under as-extruded and annealed conditions has been investigated within the temperature range from room temperature to $450^{\circ}C$. It can be seen that within entire temperature range, the electrical resistivity of composites was higher than that of an unreinforced matrix alloy under the same condition of either as-extrusion or annealing. The temperature dependence of both exhibited positive incline like a typical metal. The variation of electrical resistivity of an unreinforced matrix alloy with temperature from ambient temperature to $450^{\circ}C$ was nearly monotonous, while those of composites increased monotonously at low temperature and rose to a high level after about $250^{\circ}C or 275^{\circ}C$. The difference of these temperature dependences on electrical resistivity can be interpreted as qualitatively the interfaces of $SiC_{w}$ fibers and matrix, where act as nucleation sites.