• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1479-1481
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• 2002

AlN thin films were deposited on Si(100) and $SiO_2$/Si substrates using R.F. magnetron sputtering system. The effect of various deposition conditions on the crystal orientation of AlN films was investigated to obtain a highly (002)-oriented films. SAW filters were fabricated using AlN films with various thicknesses and their frequency response characterizations were measured. Experimental results showed that the (002)-orientation and surface roughness of AlN films played a crucial role of determining the frequency response of AlN SAW devices.

• Proceedings of the Korean Society of Crop Science Conference
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• 2020.11a
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• pp.173-173
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• 2020

• Proceedings of the Korean Society of Crop Science Conference
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• 2020.06a
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• pp.181-181
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• 2020

• Proceedings of the Korean Society of Crop Science Conference
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• 2020.11a
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• pp.140-140
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• 2020

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.1
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• pp.31-34
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• 1995

Ten specimens (5 males and 5 females) of the pufferfish, fugu stictonotus ('gachilbog'), were collected at a fish market of Pusan, Korea in July 1993, and examined for anatomical distribution of toxicity by mouse assay method. The frequency of toxic specimens was $40\%\;for\;liver,\;60\%$ for ovary, $40\%\;for\;skin\;and\;60\%$ for bile in female puffers. The highest toxicities were 107, 107, 29 and 93MU/g for liver, ovary, skin and bile, respectively; and average toxicity $\pm S.E.\;values\;were\;14\pm11,\;48\pm22.4\pm3\;and\;12\pm9MU/g,$ respectively. The range of total toxicity was shown to be from 0 to 35,316MU. The characteristic pattern of toxin distribution observed on these specimens was exhibited; both muscle and testis were non-toxic, but others were weakly toxic. Also, there was significant difference for toxicity between male and female specimens.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.4
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• pp.543-548
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• 2018

Ferroelectric $Bi_4Ti_3O_{12}$ films were deposited on $SrTiO_3(100)$ and Si(100) substrate by using conductive $SrRuO_3$ films as underlayer, and their ferroelectric and electrical properties were investigated depending on crystal structure and orientation. C-axis oriented $Bi_4Ti_3O_{12}$ films were grown on well lattice-matched pseudo-cubic $SrRuO_3$ films deposited on $SrTiO_3(100)$ substrate, while random-oriented polycrystalline $Bi_4Ti_3O_{12}$ films were grown on $SrRuO_3$ films deposited on Si(100) substrate. The random-oriented polycrystalline film showed a good ferroelectric hysteresis property with remanent polarization ($P_r$) of $9.4{\mu}C/cm^2$ and coercive field ($E_c$) of 84.9 kV/cm, while the c-axis oriented film showed $P_r=0.64{\mu}C/cm^2$ and $E_c=47kV/cm$ in polarizaion vs electric field curve. The c-axis oriented $Bi_4Ti_3O_{12}$ film showed a dielectric constant of about 150 and lower thickness dependence in dielectric constant compared to the random-oriented film. Furthermore, the c-axis oriented $Bi_4Ti_3O_{12}$ film showed leakage current lower than that of the polycrystalline film. The difference of ferroelectric properties in two films was explained from the viewpoint of depolarization effect due to orientation of spontaneous polarization and layered crystal structure of bismuth-base ferroelectric oxide.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.5
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• pp.46-51
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• 1989

The degradation phenomena induced by hot-carrier injection was studied from the shift of threshold voltage and subthreshold current curve in LDD NMOSFET degraded under different DC stress-biases. Threshold voltage shift ${Delta}V_{tex}$ defined in saturation region was separated into contri butions due to trapped oxide charge $V_{ot}$ and interface traps ${Delta}V_{it}$ generated from midgap to threshold voltage. Under th positive stress electric field (TEX>$V_g>V_d$) condition, the shift of threshold voltage was attributed to the electrons traped ar gate oxide but subthreshold swing was not negative stress electric field ($V_g) condition, holes seems to be injected positive charges so threshold voltage and subthreshold swing were increased.

• Journal of the Korea Convergence Society
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• v.9 no.9
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• pp.41-46
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• 2018

Six sigma methodology is the management tools not only can cause productivity enhancement through the quality control and cost reduction of products and services but also can be applied to various activities of corporates such as research and development. Development of high-density information storage media and devices is indispensible to accomplish the information convergence era. In this paper, we report the case of applying six sigma methodology and tools to the development project of high-density information storage media. The standard DMAIC process was applied to the project and pursuing goals and tools and results in each stage were explained in detail. By adopting the methodology, we could establish fabrication methods of information storage media of recording density higher than $250Gb/in^2$ with high uniformity and reproducibility. The magnetic property and performance of fabricated media were confirmed through measurement of the magnetic hysteresis curve.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.382-382
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• 2011

보다 저렴한 다결정 실리콘 웨이퍼를 사용한 다결정 실리콘 태양전지의 발전효율개선을 위해서는 태양광스펙트럼의 표면 흡수기구를 최적화하고, 전자-정공쌍의 생성극대화 및 재결합 기구 제어를 통한 전하운바자들의 안정적인 분리와 전극으로의 효율적인 수집이 필수적인다. 현재 양질의 다결정 실리콘 웨이퍼에 기반한 다결정 실리콘 태양전지 양산공정에서 16~17% 발전효율이 이루어지고 있으며 18% 이상의 발전효율을 얻기 위해서는 보다 더 우수한 품질의 다결정 실리콘 웨이퍼가 요구된다. 본 연구에서는 15.5~16.5% 대역의 평균 발전효율을 갖는 15.6 cm${\times}$15.6 cm 크기 고효율 다결정 실리콘 태양전지 전면의 전자발광(EL : electroluminescence)데이터로부터 효율기여도가 높은 위치와 상대적으로 기여도가 낮은 위치들을 선정하여 380~1050nm 파장대역의 광선속에 대해 국부적인 외부양자효율(EQE : external quantum efficiency)을 측정하고 투과전자현미경(TEM : tunneling electron microscope) 등을 활용하여 결정방향 등에 기인하는 양자효율 악화기구를 분석하였다. 결론적으로 15%대의 상대적으로 낮은 발전효율을 보이는 태양전지들은 300~600 nm 단파장 영역에서 양자효율이 상대적으로 낮은 저급한 결정성의 웨이퍼에 기인하고 16.5%이상의 높은 발전효율을 갖는 태양전지들은 단파장영역에서 높은 양자효율을 갖는 영역이 수광면적의 80~90%를 차지하는 것으로 밝혀졌다. 이와 더불어 15%대의 발전효율을 갖는 태양전지에서는 600~1100 nm 파장대역에서 상대적으로 악화된 양자효율을 갖는 저급한 결정성 영역이 30~40%를 차지하였으나 16.5%대역의 고효율 태양전지에서는 저급한 결정성 영역이 5~10%를 차지하여 대조를 보였다. 따라서 18%이상의 높은 발전효율을 갖는 다결정 실리콘 태양전지의 양산을 위해서는 양자효율이 우수한 양품의 웨이퍼를 기반으로 표면 texturing을 통해 평균 태양광 흡수율을 90%이상으로 개선하고, 보다 미세한 프론트 전극패턴을 통해 수광면적을 개선하고 선택적인 에미티공정 기술 등을 적용할 필요가 있음을 제안하고자 한다.

• Korean Journal of Head & Neck Oncology
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• v.10 no.2
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• pp.91-101
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• 1994

Nodular thyroid disease is a common clinical problem. The problem in clinical practice is to distinguish malignant or potentially malignant tumor from harmless nodules. The cases of thyroid nodule surgically managed at Department of General Surgery, Soon Chun Hyang Univ. Hospital during the period Jan. 1985 to July. 1992 were reviewed retrospectively. To assess method of distinguishing malignant from benign lesions of the thyroid gland, we reviewed 162 patients with thyroid nodule. There were 61(37.7%) malignant nodules and 101(62.3%) benign nodules. According to the review, distinguishing the benign from the malignant nodule with history, physical examination, clinical manifestation, and duration of illness was not suggested sufficiently. In ultrasonogram of 73 cases, 57.5% of nodules were solid, 20.6% were cystic, 21.9% were mixed solid and cystic. Of these, 28.5% of the operated solid lesions, 12.5% of the mixed lesions, and only 6.7% of the cystic lesions were malignant. Thyroid scanning of 82 cases revealed cold nodules in 60 patients(73.2%), of which 26 cases were malignant(36.6%) 137 patients underwent fine needle aspiration cytology(FNAC), and these results were as follow: sensitiviey was 70.6%, specificity was 93.0%, false-positive rate was 14.3%, and false-negative rate was 15.8%. 41 patients underwent frozen biopsy, and the results as follow: sensitivity was 80.0%, specificity was 89.7%. Neither scintigraphy nor ultrasonogram has sufficient specificity to distinguish benign from malignant nodule. But FNAC and frozen biopsy have sufficient accuracy to differentiate benign from malignant nodule. In the benign nodules, the most common type of operation was total lobectomy (60.4%). Of the malignant nodules, total thyroidectomy with or without modified radical neck dissection was performed in 30 cases(49.2%). We conclude that the single technique used to determine the differential diagnosis of a thyroid nodule are unrealiable. It is therefore essential to combine all avaiable clinical and laboratory information.