• Journal of the Korean Ceramic Society
• /
• v.33 no.6
• /
• pp.672-678
• /
• 1996

The relationship between domain switching and acoustic emission (AE) during poling was investigated using the tetragonal ferroelectric ceramics with composition of (Pb,La)TiO3+0.01MnO2 The amount of AE generation during poling increased with increasing dc electric field and raising temperature. It was confirmed that the change of the amount of AE generation with poling condition resulted from the difference of the amount of 90$^{\circ}$ domain switching and total amount of AE generation for 10 minutes was approximately proportional to the amount of 90$^{\circ}$domain switching. The A generations of two specimens which have different tetragonality rations(c/s rations) 15 at% and 24at% La-doped were also investigated. The sample with c/a ratio of 1.012 where 90$^{\circ}$ domains are dominate had larger amount of AE generation and 90$^{\circ}$ domain switching compared with the sample with c/a ratio of 1.004 where 180$^{\circ}$ domains are dominant.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.7 no.4
• /
• pp.96-101
• /
• 2008

Due to improve form accuracy and surface roughness of a aspheric lens core that is made of Ni, the study is carried out on localization about a Subminiature Optics of Proximity and Wide Field of View. The required form accuracy P-V $0.2{\mu}m$ and surface roughness is Ra 10 nm. The design of experiment(DOE) is adopted to find a optimal cutting conditions which are spindle speed, depth of cut, feedrate. Finally, the effects of this study are replacing importation and strengthening competitiveness through the localization of the Subminiature Optics of Proximity and Wide Field of View.

• Korean Journal of Pharmacognosy
• /
• v.27 no.3
• /
• pp.178-183
• /
• 1996

Seven phenolic compounds were isolated from the leaves of Spiraea salicifolia. Their structures were characterized as cinnamic acid, ${\rho}-hydroxy$ cinnamic acid, ${\rho}-methoxy$ cinnamic acid, $1-O-coumaroyl-{\beta}-D-glucopyranose$, $1-O-caffeoyl-{\beta}-D-glucopyranose$, hyperoside and quercetin $3-O-(6'-O-{\alpha}-L-arbinopyranosyl)-{\beta}-D-galactopyranoside$ by chemical and spectroscopic evidence.

• Journal of the Korean Ceramic Society
• /
• v.32 no.7
• /
• pp.793-798
• /
• 1995

The relaxation of the intrinsic stresses in the diamond films fabricated by the hot filament CVD was studied, and it was confirmed that the tensile intrinsic stresses in the films could be controlled without any degradation in the quality of the diamond films. The tensile intrinsic stresses in the films decreased from 2.97 to 1.42 GPa when the substrate thickness increased from 1 to 10mm. This result showed that the residual stress was affected by the substrate thickness as well as by the interaction between grains. Applying of ＋50 V between the W filament and the Si substrate during deposition, the tensile intrinsic stress in the film deposited at 0 V was decreased from 2.40 GPa to 0.71 GPa. Such large decrease in the tensile intrinsic stress was due to $\beta$-SiC which acted as a buffer layer for the stress relaxation. However, the application of the large voltage above ＋200V resulted in the change of quality of the diamond film, and nearly had no effect on relaxation in the tensile intrinsic stress.

• Journal of the Korean Ceramic Society
• /
• v.33 no.9
• /
• pp.1045-1049
• /
• 1996

Pressureless-sintered polycrystalline alumina and carbon steel were joined with Ag-33.5Cu-1.5Ti (wt%) brazing alloy. SEM observation revealed that two reaction layers with different thicknesses were continuously formed between the alumina and the brazing alloy. A thick layer formed on the brazing alloy side was identified as Ti3(Cu0.93Al0.07)3O phase with diamond cubic structure. Another thin layer adjacent to the alumina was revealed as $\delta$-TiO phase of which the crystal structure was HCP with a lattice parameter of a0=0.419 nm and c0=0.284 nm. It was confirmed using XPS analysis that $\delta$-TiO was formed directly by a redox reaction of alumina with titanium ir, molten brazing alloy.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.9 no.5
• /
• pp.14-19
• /
• 2010

A computational study was carried out to analyze the characteristics of supersonic (Mach 2.0) coaxial/off-axis jet's impingements on a slanted kerf surface in laser machining. The effects of various parameters such as gas pressure, distance between nozzle exit and kerf edge surface, and application of off-axis nozzles on the impingement phenomena of the assist-gas on kerf surface were observed. The present study showed that simply increasing the assist-gas pressure for coaxial supersonic nozzle was not effective to alleviate the strength of flow separation on kerf surface. It also presented the optimized operating condition of the coaxial nozzle to have the highest skin friction values over kerf surface.

• Journal of East-West Nursing Research
• /
• v.21 no.2
• /
• pp.133-139
• /
• 2015

Purpose: The purpose of this study was to identify the effects of thermotherapy on abdominal distension and pain during colonoscopy. Methods: This study used a nonequivalent control group and a non-synchronize design. Twenty-nine participants were assigned in an experimental group and 29 in the control group. For the experimental group, electronic heating pad was applied before test throughout the entire procedure. Results: Abdominal distension and total time required for colonoscopy significantly were lower in the experimental group than those in the control group. Conclusion: The results suggest that thermotherapy can be effective to improve abdominal distension and colonoscopy time in patients with colonoscopy. Therefore, thermotherapy can be recommended for those patients undergoing of colonoscopy.

• Journal of the Semiconductor & Display Technology
• /
• v.23 no.1
• /
• pp.48-51
• /
• 2024

Recently, high-performance BLDC(Brushless DC) motors are being applied to various fields such as industrial and personal mobility devices and drones. To achieve the best performance of BLDC, sensors such as hall sensors, encoders, and resolvers are used to determine the position of the rotor, and various speed control technologies are being developed. However, due to problems with high-speed control due to external environmental factors and frequency bandwidth of semiconductor sensing devices, research on BLDC motors without semiconductor sensing devices is in progress. Therefore, in this study, a signal brush was added to the end of the rotor of a BLDC motor and the rotor position of the BLDC motor was detected by analyzing the signal output through the signal brush.

• The Korean Journal of Nuclear Medicine
• /
• v.39 no.1
• /
• pp.15-20
• /
• 2005

Purpose: Physiologic intestinal FDG uptake is frequently observed in asymptomatic individuals for cancer screening FDG PET Colonic FDG accumulation is a well-known confusing findings that interfere true cancer detection or cause false positive. The aim of this study was to evaluate the pattern and intensity of colonic uptake in whole body FDG PET in asymptomatic healthy adults and to correlate them with colonoscopic findings. Materials and Methods: We reviewed retrospectively 64 subjects (age: 27-87, M:F=31:33) who underwent both FDG PET and colonoscopy for cancer screening. FDG uptake patterns were classified as focal, segmental and diffuse. Maximum SUV were measured. The PET results were compared with colonoscopic and histologic findings. Results: In 13 patients FDG bowel uptake was interpreted as focal, in 17 patients as segmental and in 34 patients as diffuse uptake. Six adenomas (17.6%, average diameter=5.0 mm) were found in diffuse pattern, 7 adenomas (41.1%, 5.6 mm) in segmental and 4 adenomas and 1 adenocarcinoma (38.5%, 16.4 mm) in focal uptake pattern. In patients with focal uptake, four were non-adenomatous pathologic lesions (30.8%, 2 intestinal tuberculosis, 2 mucosal ulcer). There is no difference of mean SUV between patients with adenoma and with negative colonoscopic results in each group of intestinal FDG pattern (Diffuse: $1.7{\pm}0.1\;vs.\;1.9{\pm}0.5$, Segmental: $4.8{\pm}3.6\;vs.\;4.2{\pm}1.2$, Focal: $6.5{\pm}4.7\;vs.\;3.5{\pm}1.3$). large adenomas (>1 cm) can be detected more in the focal uptake pattern (4 out of 5) rather than in segmental (1 out of 7) or diffuse uptake (none) and had higher SUV ($6.3{\pm}4.8$) than small adenomas ($3.5{\pm}3.0$) (statistically insignificant). Conclusion: focal FDG uptake is associated more often with large adenoma and other pathologic findings in colonoscopy. Segmental uptake cannot discriminate presence of adenoma from negative results, while diffuse pattern may have more chance to be normal.

• Korean Journal of Poultry Science
• /
• v.3 no.1
• /
• pp.19-28
• /
• 1976

본 시험은 1967년 4부터 5월에 걸쳐 실시되었으며 공시자계수는 270수, 공시난수는 981개이었다. 공시정액은 혼합 사용하였고 주정부위는 질내 2-3cm 하였다. 조조 5시부터 각시각별로 9개구를 설정하여 1수당 0.04$m\ell$씩 1회 주정하여 수정상황을 관찰하였던 바 그 결과를 요약하면 다음과 같다. 1, 주정익일 수정율은 5시구 25%, 6시구 21.7%, 7시구 21.1%, 9시구 15.8%이었으며, 기타 시각에는 전혀 얻어지지 않았다. 2. 질내 2-3cm 부위 주정에 의하여 익일수정란을 많이 얻으려면 산란전주정의 경우와 휴산당일 주정의 경우 산란 또는 배란전 최소 3-5시간의 시차를 두고 주정하여야 된다. 질내 6-7cm 부위에 주정할 경우보다 1-2시간의 시차를 더 요한다. 산란후 주정의 경우에는 익일수정란이 전혀 얻어지지 않았다. 3. 1주간의 주정시각별 수정율은 오전의 평균은 29.9%, 오후의 평균은 55.2%로서 양자사이에 고도의 유의차가 인정된다. 4. 산란전(오전)에 주정하여 높은 일주간 수정율을 얻으려면 주정익일 경우와 마찬가지로 최소 3-5시간 이상의 시차를 두고 주정하여야 된다. 이에 적합한 주정시각은 오전 3-5시로 추찰된다. 5. 산란후 주정의 경우는 산란후 2시간 이상의 시차에서 높은 1주간 수정율이 얻어졌다. 6. 휴산당일 주정의 경우에 있어서의 수정율은 오전의 평균은 32.6%, 오후의 평균은 51.5%로서 양자 사이에 고도의 유의차가 인정된다. 7. 종합적으로 보아 오후 3시경부터 일몰시까지가 실지 인공수정에 있어 가장 적당한 주정시각임이 밝혀졌다. (중략)