• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.247-251
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• 2004

반도체 소자의 제조에 있어 실리콘 표면에 성장한 자연산화막을 제거하기 위해 일반적으로 습식 세정 기술이 이용되어 왔다. 하지만 소자의 최소 선폭(design rule)이 nano급으로 고집적화 됨에 따라 contact hole 바닥의 자연산화막을 깨끗이 제거하는데 있어서 그 한계를 나타나고 있다. 이에 대한 효과적인 대안 공정으로 가스 건식 세정 기술이 연구되고 있다. 본 논문에서는 한 번에 50매 이상의 웨이퍼를 처리함으로써 생산성 측면에서 월등한 배치식 설비에서 원거리 플라즈마(remote plasma) 장치에서 2.450Hz의 마이크로웨이브(${\mu}$-wave)에 의해 형성시킨 수소라디칼과 $NF_3$ 가스를 이용하여 실리콘에 결함을 주지 않고 자연산화막을 선택적으로 제거하는 공정에 대해 고찰하였다. AFM을 이용한 표면분석, TEM을 이용한 물성분석, 그리고 ToF-SIMS 및 XPS를 이용한 화학 분석을 습식 및 건식 세정을 비교 평가한 결과, 건식 세정 공정이 실리콘 표면에 결함을 주지 않고 자연산화막을 제거 할 수 있음을 확인하였다. 산화막$(SiO_2)$, 질화막$(Si_3N_4)$, 그리고 다결정 실리콘(Poly-Si) 등의 각 막질별 식각 특성을 고찰하였으며, $NH_3$의 캐리어 가스인 $N_2$의 주입량을 조절함으로써 수소라디칼 형성 효율의 개선이 가능하였으며, 이로부터 게이트와 소스/드레인 사이를 절연하기 위해 이용되는 질화막의 식각 선택비를 2배 정도 개선할 수 있었다. nano급 소자에 실장하여 평가한 결과에서 불산(HF)에 의한 습식 세정 방식에 비하여 약 $20{\sim}50%$ 정도의 contact 저항 감소 효과가 있음이 확인되었다.두 소자 모두 $40mA/cm^2$ 에서 이상적인 화이트 발란스와 같은(0.33,0.33)의 색좌표를 보였다.epsilon}_0=1345$의 빼어난 압전 및 유전특성과 $330^{\circ}C$의 높은 $T_c$를 보였고 그 조성의 vibration velocity는 약4.5 m/s로 나타났다.한 관심이 높아지고 있다. 그러나 고 자장 영상에서의 rf field 에 의한 SAR 증가는 중요한 제한 요소로 부각되고 있다. 나선주사영상은 SAR 문제가 근원적으로 발생하지 않고, EPI에 비하여 하드웨어 요구 조건이 낮아 고 자장에서의 고속영상방법으로 적합하다. 본 논문에서는 고차 shimming 을 통하여 불균일도를 개선하고, single shot 과 interleaving 을 적용한 multi-shot 나선주사영상 기법으로 $100{\times}100$에서 $256{\times}256$의 고해상도 영상을 얻어 고 자장에서 초고속영상기법으로 다양한 적용 가능성을 보였다. 연구에서 연구된 $[^{18}F]F_2$가스는 친핵성 치환반응으로 방사성동위원소를 도입하기 어려운 다양한 방사성의 약품개발에 유용하게 이용될 수 있을 것이다.었으나 움직임 보정 후 영상을 이용하여 비교한 경우, 결합능 변화가 선조체 영역에서 국한되어 나타나며 그 유의성이 움직임 보정 전에 비하여 낮음을 알 수 있었다. 결론: 뇌활성화 과제 수행시에 동반되는 피험자의 머리 움직임에 의하여 도파민 유리가 과대평가되었으며 이는 이 연구에서 제안한 영상정합을 이용한 움직임 보정기법에 의해서 개선되었다. 답이 없는 문제, 문제 만들기, 일반화가 가능한 문제 등으로 보고, 수학적 창의성 중 특히 확산적 사고에 초점을 맞추어 개방형 문제가 확

• Journal of the Korean earth science society
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• v.22 no.6
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• pp.528-547
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• 2001

The blastoporphyritic granite gneiss (BPGN) including much alkali-feldspar megacrysts occurs in Jiri mountains area, southwestern part of Sobaegsan massif, Korea. The BPGN is formed gneiss complexes with other gneisses in Precambrian. The BPGN was named as porphyroblastic gneiss with porphyroblasts of alkali-feldspar megacrysts by other researchers, but the BPGN includes of euhedral alkali-feldspars (microcline), and the boundary with the granitic gneiss represents sharp contact as intrusive relationship. The BPGN mainly composes of alkali-feldspar megacrysts, quartz, plagioclase, K-feldspar and biotite some almandine and accessary minerals are muscovite, chlorite, apatite, zircon and opaques. The alkali-feldspar is microcline with perthitic texture. An content of plagioclases show 30 to 40. Biotites occur two type, one is Brown biotite which shows compositional ranges of Mg/Fe+Mg ratios from 0.38 to 0.52, the other is Green Bt. which is retrograde product. Camels to be various sizes and shapes have composition of almandine with 73 to 80 mole percent, but represent retrogressive zoning from core (X$_{pyr}$: 15.9${\sim}$20.8) to rim (X$_{pyr}$:13.7${\sim}$15.9) to be evidence of retrograde metamorphism. Megacrysts of alkali-feldspar in the BPGN show rectangular shape of euhedral and some become ellipsoidal or spheroidal in shape and the average size up to 20 cm long. The megacryst includes of biotite, plagioclase and quartz, and rarely euhedral apatite as inclusions. In petrochemistry the BPGN represents granodiorite composition, characteristics of peraluminous S-type granitoid and calc-alkaline features.

• Journal of Oral Medicine and Pain
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• v.33 no.3
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• pp.247-256
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• 2008

The belief that stress leads to illness has a long history. A number of the orofacial disease are also closely associated with stress. Despite research in the relationship of stress and the orofacial diseases leading to statistically significant correlations, the pathology remains vague. In the present study, the expression of clusterin, a stress protein responsible for antiapoptosis and cytoprotection, under restraint stress condition was observed in the submandibular gland, one of the major salivary glands. Sprague-Dawley rats were divided into 2 groups: normal group and restraint stress group. The rats of restraint stress group were placed in the stress cages and then sacrificed at day 0, 3 and 5 day of the experiment. After that, the submandibular glands of all the rats were excised immediately. The levels of clusterin proteins and mRNA in the tissues were measured by immunohistochemistry and Northern blot analyses, respectively. The results were as follows: 1. In the immunohistochemistry, clusterin protein was detected only immediately after the application of restraint stress. 2. In the restraint stress group, at day 3 and 5, histologically apoptosis was induced with karyorrhectic and pyknotic changes. 3. By the restraint stress, acinic cells were destructed earlier than ductal cells. 4. In the Northern blot, mRNA of clusterin was expressed only immediately after the application of restraint stress. The overall results suggest that as an early response to stress, clusterin is expressed in the glands to protect the glandular cells from the stress. But if stress is so strong and prolonged that it can exceed the stress adaptability of the cells, then the cells may undergo apoptosis instead of producing clusterin. An Epidemiologic Study of Symptoms of Temporomandibular Disorders in Korean College Students.

• The Journal of the Petrological Society of Korea
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• v.6 no.3
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• pp.210-225
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• 1997

From their general natures of peraluminous, S-type and ilmenite-series granites, two-mica granites in the Cheongsan, Inje-Hongcheon, Yeongju and Namwon areas were originated from crust-derived granitic magma and solidified under reducing condition. Each two-mica granite in Inje-Hongcheon and Namwon districts was differentiated from the the residual magma of porphyric biotite granite and high Ti/Mg biotite granite, respectively. The genetic relationships between two-mica granite and porphyritic biotite granite in Chenongsan district and between two-mica granite and biotite granodiorite in Yeongju district are ambiguous. In Namwon district granitic magmas were water-saturated and possible water solubilities in magmas were more than 5.8wt.%. In Yeongju district two-mica granitic magma was nearly water-saturated and showed possible water solubilities between 2.4~5.8wt.%. Two-mica granitic magmas in Cheongsan and Inje-Hongcheon districts were water-undersaturated. Pressure-dependent minimum melt compositions (0.5~2kb) and petrographic textures of two-mica granites in Inje-Hongcheon and Yeongju districts represent that the granites intruded and solidified at shallow level, whereas those in Cheongsan and Namwon districts exhibit relatively deeper level of granitic intrusion (2-3kb). The intersection of granite-solidus/muscovite stability indicates that magmatic primary muscovite can be crystallized from the water-saturated magma above 1.6kb (ca. 6km), but below the pressure muscovite can be formed by the subsolidus reaction. On the other hand, more pressure would be necessary for the crystallization of primary muscovite from the water-undersaturated magma. This pressure condition can explain the occurrence of primary and secondary muscovites from the two-mica granites in the areas considered. The experimental muscovite stability must be cautious of the application to examine the origin of muscovite. The muscovite stability can move toward high temperature field with adding of Ti, Fe and Mg components to the octahedral site of pure muscovite end member.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.167-173
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• 2002

This experiment was conducted to figure out the change of soil physical properties, rice growth and yield with the years of continuous cultivation in direct dry-seeding and no-tillage machine transplanting. Experiments were conducted at NHAES(National Honam Agricultural Experiment Station, RDA, Iksan, Cheon Buk Province, South Korea) with a rice variety "Dongjinbyeo" from 1995 to 2000. In no-tillage machine transplanting cultivation, organic matter in soil was higher than that on direct dry-seeding and was significantly high in topsoil. Problematic weed species were E. crus-galli B., A. keisak H., and L. japonica M. Plant height and tiller number m-2 were higher in common-tillage during the total growth duration. The highest weedy rice occurrence of 27.5% was observed in live years' continuous direct dry-seeding and followed by 6.2%, in four years', and 3.7%, in three years'. The highest yield reduction of 38% was observed in five years' continuous direct dry-seeding. The reduction may resulted from the competition between weedy rice and cultivated rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.5
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• pp.405-412
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• 1993

This experiment was conducted to investigate the effects of water depths on seedling stand and early growth of califonia rice varieties, S201, M202, A301, Italico livorno and Korean variety, Hwaseongbyeo, and barnyardgrass (Echinochloa crus-galli) The coleoptile length of rice was longer with deep water depth while for the radicle length shorten. As water depth was increased, the percentage of seedling stand were decreased slightly in rice, while sharply increased in barnyardgrass. Plant height of rice with increasing water depth were longer, whereas that of barnyardgrass reduced significantly with weaker. Tiller number of rice and barnyardgrass were significantly reduced as water depth increased. Dry matter weight and healthy score of rice seedling at 35DAS were highest in 7.5cm water depth followed saturated moisture, 15, and 22.5cm water depth, while for barnyardgrass those were especially negatively affected by deep water depth. These results showed that the seedling stand and early growth of barnyardgrass was highly suppressed by deeper water levels compared with rice. Rice cultivars which are showes growth characteristics in deeper water levels at early growth stage were Italico livorno and S201 in Japonica / Indica.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.4
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• pp.494-503
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• 1995

The selection of salt tolerant rice variety needs an effective method in its testing. Salinity of irrigated water, 0.5% at seedling stage, 0.6% at tillering stage, and 0.9% at panicle formation stage were treated to test salt tolerance of rice using 45 cultivars. At tillering stage, salty water irrigation reduced plant height to 22.6% in early maturing rices(EMR), 30.5% in medium maturing rices(MMR), and 20.9% in medium-late maturing rices(MLMR), and also reduced number of tillers to 11.2% in EMR, 36.2% in MMR, and 36.0% in MLMR compared to rices grown in non-salty water irrigation. At panicle formation stage of rice, salty water irrigation affected plant height and tiller numbers that showed varietal differences. As salt tolerant rice cultivars, Daegwangbyeo, Namweonbyeo, Sinseonchalbyeo, Gyehwabyeo, and Daeyabyeo were selected. Jinbubyeo, Donghaebyeo, and Tamjinbyeo were weak in salty water irrigation.

• Economic and Environmental Geology
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• v.39 no.5 s.180
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• pp.555-566
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• 2006

Major, trace and rare earth elements data of the Cretaceous Jindong granitic rocks were investigated in order to constrain the magma source characteristics and to establish the paleotectonic environment of the southwestern part of the Gyeongsang Basin. Geochemical signatures of the granitic rocks from the study area indicate that all of the rocks have characteristics of calc-alkaline series in the subalkaline field, and progressively shift from metaluminous to peraluminous with differentiation. In the variation diagrams, the overall geochemical features of the granites show systematic variations in major and trace elements. Chondrite normalized REE patterns show generally enriched LREE((La/Yb)c=4.2-12.8) and slight negative to flat Eu anomalies. Rb-Sr isotope data of the Jindong granites show that the whole rock age and Sr initial ratio are $114.6{\pm}9.1Ma$ and 0.70457, respectively. The Sr initial ratio of the Jindong granites is very similar to those of the Creataceous granites from Masan, Kimhae and Busan area($^{87}Sr/^{86}Sr=0.7049-0.707$). These results suggest that the magma have the mantle signature and intruded into the area during the early Cretaceous age. The Jindong granites have higher $Al_{2}O_{3},\;Na_{2}O$, Sr and lower $K_{2}O$, Y concentrations compared with typical calc-alkaline granitic rocks. These adakitic signatures are similar to those of adakitic pluton on Kyushu Island, southwest Japan arc. On the ANK vs. ACNK and tectonic discrimination diagrams, parental magma type of the granites corresponds to I-type, VAG granite. Interpretations of the geochemical characteristics of the granitic rocks favor their emplacement at continental margin during the subduction of Izanagi plate.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.103-109
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• 2016

Polyethylene pipes has useful benefits which are anti-corrosive and flexible material, so it is used to gas pipes but also class 3 water pipes of nuclear power plant, process pipes of petrochemical plant and chemical plant. So the usage of polyethylene pipes is widely increased. But it has been limited for the usage of polyethylene, because it can not be directly detected to fusion joints by using non destructive evaluation. Polyethylene pipes are connected by two methods, one is butt fusion and the other is electrofusion. Butt fusion is widely used to connecting the pipes. It is proposed to method for determining the reliability of joints in this study that is detection of the melt flow zone at fusion joints. In this study, middle density polyethylene is used, outside diameter of the test specimen is 225mm and thickness is 20.5mm. Speed of ultrasonic of this test specimen is 2,200m/s. Test specimens were fabricated by varying the heating time which means from 0% to 130% applying time through heating plate to polyethylene for detecting melt flow zone. Also 4 additional test specimens were made, one was made that not scrapping attached surface of pipes but applying 100% of the proper heating time and the others were made to include of soil, gravel and vinly tape paper at fusion joints, that were also applied 100% of proper heating time. Ultrasonic testing to measure the melt flow zone of 20 test specimens was conducted by using 3.5MHz and 5.0MHz ultrasonic probes and melt flow zone measuring was conducted to three times at different point to one specimen. To differentiate the melt flow zone signal, post image processing was equally conducted to all test results and image levels, contrast, sharpen, threshold were adopted to all teat results and the test results were displayed gray scale. From the results, for the shorter heating times the reflection area of multiple echo have been increased, so the data was obtained from the position where it can be eliminated as much as possible. At 80% of proper heating time(168 sec.), the signal of melt flow zone was obtained clearly, so measuring could be conducted. From 7% of proper heating time(15 sec.) to shorter heating times. we could not obtain the signal because test specimen was not fused. From the result, we can verify that measuring of melt flow zone by using phased array ultrasonic imaging method is possible. And we can verify to complete and incomplete butt fusion by measuring the melt flow zone.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.165-165
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• 2017

지난 수 십 년 동안, 전 세계적으로 자원의 소비가 급격히 증가하게 되면서 최근 자원 고갈은 물론 환경오염이 커다란 이슈로 문제가 되고 있다. 이에 따라 재료 관련 분야에 있어서는 보다 효율적이고 친환경적인 방법으로 자원을 활용해야 된다는 필요성이 대두되었고 이와 같은 관점에서 목적하는 성분이 우수하고 환경 친화적인 표면처리 재료 개발연구가 활발하게 진행되고 있는 실정이다. 그 중 플라즈마 전해 산화(Plasma Electrolytic Oxidation, PEO)는 알루미늄, 마그네슘 등의 경금속의 경도를 향상시키고 높은 내마모성, 내식성을 갖게 하는 표면처리로써 그 관심이 증가하고 있다. 이 플라즈마 전해 산화는 일반적으로 공정비용 대비 효과적이고 환경 친화적이며 코팅 성능 면에서 우수하다고 알려져 있다. 이러한 고유한 특성으로 인해 플라즈마 전해 산화 코팅은 최근 몇 년 동안 기계, 자동차, 우주항공, 의학 및 전기 산업 등의 분야에서 그 적용이 점차 증가하고 있는 상황이다. 한편, 플라즈마 전해 산화 코팅을 하는 모재들의 경우 부동태 산화피막을 용이하게 형성할 수 있는 특성의 모재에 한정되고 있어서 그 응용확대에 한계가 있는 것이 사실이다. 따라서 본 연구에서는 플라즈마 전해 산화법을 사용하여 용융알루미늄도금 강판 상에 산화피막 형성을 시도하였다. 전원공급 장치의 양극은 전해질 속에 잠겨있는 작동전극에 연결하고 음극은 대전극 역할을 하는 스테인레스강 전해질 용기에 연결되었다. 전해질은 Sodium Aluminate 및 기타 첨가제를 함유한 것을 사용하였고 온도는 열교환기를 사용하여 $30^{\circ}C$ 이하로 유지되었다. 또한 여기서 전류밀도는 $5{\sim}10A/dm^2$, 실험 주파수는 700Hz, Duty cycle은 30 및 90%의 각 조건에서 공정처리 시간을 각각 30분 및 60분 동안 진행하였다. 이와 같은 조건에서 형성한 막들에 대해서는 주사형전자현미경(SEM)을 이용하여 코팅 막의 표면 및 단면의 모폴로지를 관찰하였음은 물론 EDS 및 XRD 측정을 통하여 원소조성분포 및 결정구조를 각각 분석하였다. 또한 이 코팅 막들에 대한 내식성은 5% 염수분무 환경 중 노출시험(Salt spray test), 3% NaCl 용액에서의 침지 시험 및 전기화학적 동전위 양극분극(Potentiodynamic Polarization) 시험을 진행하여 평가하였다. 이상의 실험결과에 의하면, 제작조건별 플라즈마 전해 산화 코팅 막의 모폴로지 및 결정구조가 상이하게 나타나는 것을 알 수 있었다. 코팅 막의 모폴로지 관찰 결과, 공정 시간에 비례하여 표면에 존재하는 원형 기공의 수는 감소하였으나 그 크기가 커지고 크레이터의 직경 또한 커진 것이 확인되었다. 이 기공은 마이크로 방전에 의해 형성된다고 알려져 있는데 공정 시간이 증가함에 따라 코팅 두께가 점차 증가하여 마이크로 방전의 빈도수가 줄어들고 그 강도는 증가하게 되어 기공 크기가 증가한 것으로 사료된다. 또한 공정시간이 긴 시편에서 표면에 크랙이 다수 존재하는 것으로 확인되었다. 이것은 방전에 의해 고온이 된 소재가 차가운 전해질과 만나게 되어 생긴 큰 온도구배로 인해 강한 열응력이 발생하여 균열을 초래한 것으로 보인다. 조성원소 분석 결과 원형 기공 주변의 크레이터 영역에는 알루미늄이 풍부하였으며 그 주변에 결절상을 갖는 구조에서는 전해질 성분의 원소가 포함되어 있는 것이 확인되었다. 이러한 코팅 막의 표면 특성은 내식성에 영향을 주게 된 원인으로 사료된다. 동전위 분극측정 결과에 의하면 플라즈마 전해 산화 공정 시간이 길어질수록 부식전류밀도가 증가하였다. 이것은 공정시간이 길어짐에 따라 강한 방전이 발생하여 기공의 크기가 증가하고 크랙이 발생하게 되면서 내식성이 저하된 것으로 판단된다. 종합적으로 재료특성 분석 및 내식성 평가를 분석한 결과, 플라즈마 전해 산화의 공정 시간이 너무 길게 되면 오히려 내식성은 저하되는 것이 확인되었다. 이상의 연구를 통하여 고내식 특성을 갖는 플라즈마 전해 산화 막의 유효성을 확인하였으며 용융알루미늄강판 상에 실시한 플라즈마 전해 산화 처리에 대한 기초적인 응용 지침을 제시할 수 있을 것으로 사료된다.