• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
• /
• pp.882-884
• /
• 1999

금속 다층박막과 미세입상 합금박막에서 발견된 Giant Magnetoresistance(GMR)현상에 고무되어 최근에는 50년대에 밝혀졌던 산화물 자기저항 재료에 관하여 새롭게 연구하고 있다. Perovskite 구조를 가지는 $La_{1-x}Ca_{x}MnO_{3}$ 박막에서 큰 자기저항을 얻었으며 이를 Colossal Magentoresistance (CMR)이라 한다. 본 연구에서는 $La_{1-x}Ca_{x}MnO_{3}$ 분말을 고상반응법과 자발착화연소 합성법(Glycine-Nitrate Process)으로 각각 제조하였으며 비교 분석하였다. TGA을 이용하여 불순물과 미반응 물질을 확인하여 적당한 하소온도를 결정하였고 XRD를 이용하여 결정상을 분석하였다. Dilatometer를 이용해 $1400^{\circ}C$까지의 열팽창율을 측정하였다. BET로 비 표면적을 비교하였으며, 주사전자현미경(SEM)으로 각각 제조된 분말의 입자상태와 입자성장을 확인하였다. GNP법으로 합성한 경우가 고상반응법을 이용한 경우보다 입자의 크기가 submicron 단위로 미세하고 비표면적도 수배 컸으며, 고순도의 perovskite 구조를 갖는 $La_{1-x}Ca_{x}MnO_{3}$ 분말을 얻을 수 있었다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
• /
• pp.137-141
• /
• 1999

금속 다층박막과 미세입상 합금박막에서 발견된 Giant Magnetoresistance(GMR) 현상에 고무되어 최근에는 50년대에 밝혀졌던 산화물 자기저항 재료에 관하여 새롭게 연구하고 있으며 perovskite 구조를 가지는 La$_{1-x}$ Ca/xub x/MnO$_{3}$ 박막에서 큰 자기저항을 얻었으며 이를 Colossal Magentoresistance (CMR) 이라 부른다. 본 연구에서는 La$_{1-x}$ Ca/xub x/MnO$_{3}$ 분말을 하소온도를 700-90$0^{\circ}C$로 변화시킨 고상반응법과 자발착화연소합성법(Glycine-Nitrate Process) 으로 각각 제조하였으며 비교 분석하였다. TG-DTA을 이용하여 불순물과 미반응 물질을 확인하여 적당한 하소 온도를 결정하였고 XRD를 이용하여 결정상을 분석하였다. 주사전자현미경(SEM)으로 각각 제조된 분말의 하소후 입자의 크기를 비교하였다. GNP법으로 합성한 경우가 고상반응법을 이용한 경우보다 입자의 크기가 submicron 단위로 미세하고 균질하며 고순도의 perovskite 구조를 갖는 La$_{1-x}$ Ca/xub x/MnO$_{3}$ 분말을 얻을 수 있었다.었다.

• 센서학회지
• /
• 제18권3호
• /
• pp.234-238
• /
• 2009

We have investigated the effects of dopant on the thermoelectric properties that $La_{(1-x)}M_xCoO_3$(M=Sr, Ca;x=0, 0.1) bulk ceramics fabricated by the conventional solid state reaction method. The Seebeck coefficient of $La_{(1-x)}M_xCoO_3$(M=Sr, Ca;x=0, 0.1) bulk ceramics was measured at wide temperature range from 300 K to 673 K. The thermoelectric properties(Seebeck coefficient and electrical resistivity) depend strongly on the kinds of dopants. Sr and Ca dopant decrease the Seebeck coefficient. Density of sintered $La_{0.9}Sr_{0.1}CoO_3$ ceramic at 1523 K was 7.12 $g/cm^2$ and Seebeck coefficient was 35 ${\mu}V/K$ at 663 K. However, the electrical resistivity of the Sr doped sample was low and stable.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
• /
• pp.125-125
• /
• 2014

In 1991, Prof. Toshio Masuda of Kyoto University for the first time synthesized a representative of diphenylacetylene polymer derivatives, poly[1-phenyl-2-(p-trimethylsilyl)phenylacetylene] [PTMSDPA]. This polymer is highly soluble nevertheless a ultra-high molecular weight (Mw) of > $1.0{\times}10^6$ which showed excellent chemical, physical, mechanical properties [1]. As one of the most interesting features of PTMSDPA, Prof. Katsumi Yoshino of Osaka Univ. reported that this polymer emits an intense fluorescence (FL) in a visible region because of the effective exciton confinement within the resonant structure between the polyene pi-conjugated chain and side phenyl full-aromatic bulky groups [2]. Very recently, Prof. Ben-Zhong Tang of Hong-Kong Institute of Science and Technology clarified the idea that the FL emission of disubstituted acetylene polymer derivatives originates from intramolecular excimer due to the face-to-face stacking of the side phenyl groups [3]. Thus, to know what influence to intramolecular excimer emission in the film as well as to further understand how the intramolecular excimer forms in the film became more crucial in order to further precisely design the optimized molecular structure for highly emissive, substituted acetylene polymers in the solid state. In recent studies, we have focused our interests on the origin of the FL emission in order to expand our knowledge to developments of novel sensor applications. It was found that the intramolecular phenyl-pheyl stack structure of PTMSDPA in film was variable in response to various external chemical stimuli. Using PTMSDPA and its derivatives, we have developed various potential applications such as latent fingerprint identification, viscosity sensor, chemical-responsive actuator, gum-like soft conjugated polymer, and bioimaging. The details will be presented in the 49th KVS Symposium held in Pyong Chang city.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.389.1-389.1
• /
• 2016

The flexible solid state device has been widely studied as portable and wearable device applications such as display, sensor and curved circuits. A zero-bias operation without any external power consumption is a highly-demanding feature of semiconductor devices, including optical communication, environment monitoring and digital imaging applications. Moreover, the flexibility of device would give the degree of freedom of transparent electronics. Functional and transparent abrupt p/n junction device has been realized by combining of p-type NiO and n-type ZnO metal oxide semiconductors. The use of a plastic polyethylene terephthalate (PET) film substrate spontaneously allows the flexible feature of the devices. The functional design of p-NiO/n-ZnO metal oxide device provides a high rectifying ratio of 189 to ensure the quality junction quality. This all transparent metal oxide device can be operated without external power supply. The flexible p-NiO/n-ZnO device exhibit substantial photodetection performances of quick response time of $68{\mu}s$. We may suggest an efficient design scheme of flexible and functional metal oxide-based transparent electronics.

• 한국생산제조학회지
• /
• 제24권1호
• /
• pp.31-37
• /
• 2015

A laser line welder using a solid-state laser (Yb:YAG) has been manufactured for joining ultra-thin cold-rolled steel coils in steelworks. The coils to be welded primarily range from 0.15 to 0.3 mm in thickness and 800 to 1,100 mm in width. Because the steel plate is extremely thin, it is very important to control the stop positions of the clamp at cutting and welding points. In this study, both hydraulic proportional control valves and LVDT sensor embedded cylinders were used to precisely control and monitor the positions of clamps with complementary stoppers. As a result, the positions could be controlled within an error of ${\pm}30{\mu}m$. Erichsen cupping tests on the welded joints show that the Erichsen index ranges from 4.4 to 4.6 mm. Furthermore, the tensile strength of welding points is comparable to that of the base metal.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
• /
• pp.28-28
• /
• 2000

Low-cost solid-state inertial sensors of three rate Gyroscopes and a triaxial Accelerometer are evaluated in static and dynamic environments. As a interim result, error models of each inertial sensors are generated. Model parameters with respect to temperature are acquired in static environment. These error models are included in an Extended Kalman Filter(EKF) to compensate bias error due to temperature variation. Experimental results in dynamic environment are included to show the validity of the each error model and the performance improvement of a compensated low cost inertial sensors for a navigational application

• 센서학회지
• /
• 제25권1호
• /
• pp.41-45
• /
• 2016

In this study, LET (Linear Energy Transfer) calibration of CR-39 SSNTD (Solid State Nuclear Track Detector) was performed using 500 MeV/u Fe heavy ions in HIMAC (Heavy Ion Medical Accelerator) for high LET radiation dosimetry. The irradiated CR-39 SSNDT were etched according JAXA (Japan Aerospace Exploration Agency) etching conditions. And the etched SSNTD were analyzed by using Image J. Determined dose-mean lineal energy ($\overline{y_D}$) of 500 MeV/u Fe is about 283.3 keV/um by using the CR-39 SSNTD. This value is very similar result compare to the results calculated by GEANT4 Monte Carlo simulation and measured with TEPC active radiation detector. We confirmed that the CR-39 SSNTD was useful for high LET radiation dosimetry such as heavy iron ions.

• 한국자기공명학회논문지
• /
• 제23권3호
• /
• pp.73-80
• /
• 2019

Nitrogen-vacancy (NV) is one of the most popular solid-state spin systems for quantum sensing. NV has been used for vector magnetometry with nanometer spatial resolution and sensors for nuclear magnetic resonance (NMR) in samples with small volume, less than 10 pL. Various studies are in progress to make NV a complementary sensor for current NMR technique. Fabricating and improving diamond itself are one of the research topics. This mini-review contains recent develops in diamond fabrication and treatment for higher NV yield. Additionally, we briefly introduce the development status of NV in NMR.

• ETRI Journal
• /
• 제32권3호
• /
• pp.440-446
• /
• 2010

Array-based gas sensors now offer the potential of a robust analytical approach to odor measurement for medical use. We are developing a fast reliable method for detection of microbial infection by monitoring the headspace from the infected wound. In this paper, we present initial results obtained from wound-state monitoring for burn patients using an electronic nose incorporating an automated solid-phase microextraction (SPME) desorption system to enable the system to be used for clinical validation. SPME preconcentration is used for sampling of the headspace air and the response of the sensor module to variable concentrations of volatiles emitted from SPME fiber is evaluated. Gas chromatography-mass spectrometry studies prove that living bacteria, the typical infectious agents in clinical practice, can be distinguished from each other by means of a limited set of key volatile products. Principal component analysis results give the first indication that infected patients may be distinguished from uninfected patients. Microbial laboratory analysis using clinical samples verifies the performance of the system.