• JSTS:Journal of Semiconductor Technology and Science
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• 제17권1호
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• pp.141-146
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• 2017

In this letter, we propose the use of tunneling field effect transistors (TFET) as a biosensor that detects bio-molecules on the gate oxide. In TFET sensors, the charges of target molecules accumulated at the surface of the gate oxide bend the energy band of p-i-n structure and thus tunneling current varies with the band bending. Sensing parameters of TFET sensors such as threshold voltage ($V_t$) shift and on-current ($I_D$) change are extracted as a function of the charge variation. As a result, it is found that the performances of TFET sensors can surpass those of conventional FET (cFET) based sensors in terms of sensitivity. Furthermore, it is verified that the simultaneous sensing of two different target molecules in a TFET sensor can be performed by using the ambipolar behavior of TFET sensors. Consequently, it is revealed that two different molecules can be sensed simultaneously in a read-out circuit since the multi-sensing is carried out at equivalent current level by the ambipolar behavior.

• Nuclear Engineering and Technology
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• 제52권6호
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• pp.1243-1251
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• 2020

Irradiation-induced damage of binderless nanoporous-isotropic graphite (NPIG) prepared by isostatic pressing of mesophase carbon microspheres for molten salt reactor was investigated by 3.0 MeV He⁺ irradiation at room temperature and high temperature of 600 ℃, and IG-110 was used as the comparation. SEM, TEM, X-ray diffraction and Raman spectrum are used to characterize the irradiation effect and the influence of temperature on graphite radiation damage. After irradiation at room temperature, the surface morphology is rougher, the increase of defect clusters makes atom flour bend, the layer spacing increases, and the catalytic graphitization phenomenon of NPIG is observed. However, the density of defects in high temperature environment decreases and other changes are not obvious. Mechanical properties also change due to changes in defects. In addition, SEM and Raman spectra of the cross section show that cracks appear in the depth range of the maximum irradiation dose, and the defect density increases with the increase of irradiation dose.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.414-414
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• 2007

In this study, Liquid Crystal (LC) alignment and tilt angle generation in Nematic Liquid Crystal (NLC) with negative dielectric anisotropy on the homeotropic PI surface with new ion beam exposure are reported. Also. high density of ion beam energy (DuoPIGatron type Ar ion gun) is used in this study. The tilt angle of NLC on the homeotropic Polyimide (PI) surface for all incident angles is measured about 38 degree and this has a stabilization trend. And the good LC alignment of NLC on the PI surface with ion beam exposure of $45^{\circ}$ incident angle was observed. Also the tilt angle of NLC on the homeotropic PI surface with ion beam exposure of $45^{\circ}$ had a tendency to decrease as ion beam energy density increase. The tilt angle could be controlled from verticality to horizontality. Also, the LC aligning capabilities of NLC on the homeotropic PI surface according to ion beam energy has the goodness in case of more than 1500 eV. Finally. the superior LC alignment thermal stability on the homeotropic PI surface with ion beam exposure can be achieved. For OCB(Optically Compensated Bend) mode driving, we can need pretilt angles control for fast response time. In this study, We success pretilt angles control. Consequently, this result can be applied for OCB mode.

• 대한금속재료학회지
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• 제47권9호
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• pp.533-541
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• 2009

Materials used for a reactor pressure vessel(RPV) are required high strength and toughness, which determine the safety margin and life of a reactor. Ni-Mo-Cr low alloy steel shows better mechanical properties than existing RPV steels due to higher Ni and Cr contents compared to the existing RPV steels. The present study focuses on effects of Ni, Cr contents on the cleavage fracture toughness of Ni-Mo-Cr low alloy steels in the transition temperature region. The fracture toughness was characterized by a 3-point bend test of precracked Charpy V-notch(PCVN) specimens based on ASTM E1921-08. The test results indicated that the fracture toughness was considerably improved with an increase of Ni and Cr contents. Especially, control of Cr content was more effective in improving fracture toughness than manipulating Ni content, though Charpy impact toughness was changed more extensively by adjusting Ni content. These differences between changes in the fracture toughness and that in the impact toughness were derived from microstructural features, such as martensite lath size and carbide precipitation behavior.

• 한국잠사곤충학회지
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• 제49권1호
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• pp.8-13
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• 2007

쪽풀 생잎에서 우려낸 색소 액에 소석회를 첨가한 후 쪽풀 색소의 침전물을 만들어서 냉동 건조시켜 쪽풀 색소를 제조하여, 그 성분을 조사한 결과 다음과 같은 결론을 얻었다. 1. UV분광광도, TLC 정성 분석, HPLC 측정 결과 쪽 분말 용액의 2개 bend가 나타났으며, 적색색소대인 540nm 와 청색 색소대인 620nm가 존재함을 알 수 있었다. 2. FT-IR 분석으로부터 $1627cm^{-1}$에서 채, $3200{\sim}3300cm^{-1}$에서 NH의 흡수대가 나타나고, 적색 및 청색 색소의 IR spectrum이 일치하였으며, 3. EI-mass 분석 결과 청색과 적색 색소의 fragment 이온의 m/z가 일치하고, $^1H_MNR$ 분석결과로부터 두 색소는 이성질체임을 알 수 있었고, 4. 쪽 염료 성분 함량을 조사한 결과 인디고 색소 4.06%와 인디루빈 1.06%이었다.

• Journal of Korean Neurosurgical Society
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• 제65권6호
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• pp.801-815
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• 2022

Objective : To evaluate the stent apposition of a low-profile visualized intraluminal support (LVIS) device in distal internal carotid artery (ICA) aneurysms, examine its correlation with clinical and angiographic outcomes, and determine the predictive factors of ischemic adverse events (IAEs) related to stent-assisted coiling. Methods : We retrospectively analyzed a prospectively maintained database of 183 patients between January 2017 and February 2020. The carotid siphon from the cavernous ICA to the ICA terminus was divided into posterior, anterior, and superior bends. The anterior bends were categorized into angled (V) and non-angled (C, U, and S) types depending on the morphology and measured angles. Complete stent apposition (CSA) and incomplete stent apposition (ISA) were evaluated using unsubtracted angiography and flat-panel detector computed tomography. Dual antiplatelet therapy with aspirin 200 mg and clopidogrel 75 mg was administered. Clopidogrel resistance was defined as fewer responders (≥10%, <40%) and non-responders (<10%) based on the percent inhibition (%INH) of the VerifyNow system. These were counteracted by a dose escalation to 150 mg for fewer responders or substitution with cilostazol 200 mg for non-responders. IAEs included intraoperative in-stent thrombosis, transient ischemic attack, cerebral infarction, and delayed in-stent stenosis. A multivariate logistic regression analysis was used to determine the predictive factors for ISA and IAEs. Results : There were 33 ISAs (18.0%) and 27 IAEs (14.8%). The anterior bend angle was narrower in ISA (-4.16°±25.18°) than in CSA (23.52°±23.13°) (p<0.001). The V- and S-types were independently correlated with the ISA (p<0.001). However, treatment outcomes, including IAEs (15.3% vs. 12.1%), aneurysmal complete occlusion (91.3% vs. 88.6%), and recanalization (none of them), did not differ between CSA and ISA (p>0.05). The %INH of 27 IAEs (13.78%±14.78%) was significantly lower than that of 156 non-IAEs (26.82%±20.23%) (p<0.001). Non-responders to clopidogrel were the only significant predictive factor for IAEs (p=0.001). Conclusion : The angled and tortuous anatomical peculiarity of the carotid siphon caused ISA of the LVIS device; however, it did not affect clinical and angiographic outcomes, while the non-responders to clopidogrel affected the IAEs related to stent-assisted coiling.

• 한국방사선학회논문지
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• 제15권6호
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• pp.781-788
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• 2021

피부는 방사선에 대한 민감도가 높기 때문에 방사선치료 시에 피부에 조사되는 선량을 정확하게 측정하여 과도한 피폭을 방지할 필요가 있다. 임상에서는 film, OSLD, TLD, glass 선량계등과 같은 선량계를 사용하여 피부선량을 측정하고 있지만, 이러한 선량계들은 피부곡면에서의 정확한 선량측정이 힘든 문제점이 있다. 본 논문에서는 이러한 문제를 해결하고자 인체 굴곡에 따라서 부착이 가능한 피부선량계를 개발하고 그 반응 특성을 평가하였다. 선량계 제작에는 높은 원자번호(Z_Pb: 82, Z_O: 8)와 밀도(9.53 g/cm³)로 방사선검출 측점에서 우수한 특성을 가지고 있는 Lead oxide(PbO)와 인체 굴곡에 따라 휘어질 수 있는 silicon 바인더를 사용하여 재조하였다. 한편 PbO 물질로 제작된 선량계의 경우 산화로 인한 성능 저하가 존재하기 때문에 parylene 등을 사용하여 성능저하를 방지해오고 있었지만, 기존에 사용된 parylene은 bending에 대한 영향을 받기 때문에 silicon을 이용한 새로운 형태의 passive layer를 제작하여 피부선량계에 적용하였다. 피부선량계의 특성평가는 SEM, 재현성, 선형성을 분석하여 평가하였다. SEM 분석을 통하여 bending에 영향을 받는지 평가하였으며, 6 MeV 에너지에서의 재현성, 선형성을 평가하여 피부선량계로 적용이 가능한지 평가하였다. SEM 분석을 통하여 선량계 표면을 관찰한 결과, parylene으로 passive layer가 올라간 parylene passive layer PbO 선량계는 구부러 졌을때, 표면에 crack이 발생하였다. 그에 반해 silicon passive layer가 올라간 silicon passive layer PbO 선량계에서는 crack 이 관찰되지 않았다. 재현성 측정 결과에서 silicon passive layer PbO 선량계의 RSD는 1.47%로 평가기준 RSD 1.5%를 만족하였으며, 선형성 평가 결과에서는 R²값이 0.9998로 나타나 평가기준 R² 0.9990을 만족하였다. silicon passive layer PbO 선량계는 bending에 따른 crack이 발생하지 않으며, 재현성, 선형성에서 높은 신호안정성과 정밀성, 정확성을 보여주어 피부선량계로의 적용이 가능한 것으로 평가되었다.

• 한국잡초학회지
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• 제8권3호
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• pp.273-282
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• 1988

1986년(年)에 전국적(全國的)으로 수집(蒐集)한 피(Echinochloa crusgalli (L.) Beauv.)를 1987년(年)에 2회(回)에 걸쳐 증식(增殖) 및 선발(選拔)하였으며 선정(選定)된 피 17종(種)을 1980년(年)에 공시(供試)하였다. 시험(試驗)은 P.E. film house내(內)의 1/5000 a의 Wagner pot에 의하여 수행(遂行)되었으며, 피 수집종(蒐集種)에 대한 잡초(雜草)로서의 생태적(生態的) 특성(特性)을 파악(把握)할 목적(目的)으로 이루어진 결과(結果)는 다음과 같다. 수집종(蒐集種) 피의 양적(量的) 및 질적형질(質的形質) 차이(差異)를 보면 57종목(種目)의 조사형질(調査形質) 가운데서 종내변이(種內變異)가 컸던 형질(形質)은 종실(種實) 100 입중(粒重), 이식후(移植後) 30일(日)까지 분벽증가속도(分蘗增加速度) 및 분벽수(分蘗數) 및 파종후(播種後) 15일(日)부터 22일(日) 사이의 건물중증가속도(乾物重增加速度)는 변이계수(變異係數)가 30---- 이상(以上)이었으며, 제(第)1엽(葉)의 크기, 22일묘(日苗)의 생체중(生體重)과 건물중(乾物重), 유효경(有效莖) 비율(比率), 주당수수(株當穗數) 및 분벽개각도(分蘗開角度)는 25---- 내외(內外)였다. 반면(反面)에 종내변이(種內變異)가 극(極)히 작았던 형질(形質)은 파종(播種)이 늦었을 때 (6월(月) 6일(日))의 출수소요일수(出穗所要日數), 22일묘(日苗)의 건물중(乾物重) 생체중비(生體重比) 및 초장(草長)으로서 변이계수(變異係數)가 5---- 내외(內外)였다. 질적형질(質的形質)로서도 엽(葉), 엽초(葉鞘), 중조(中助), 절(節), 수(穗) 및 종실(種實)의 색깔과 입상(立狀), 엽록(葉綠)의 거치장단(鋸齒長短), 종보형상(種寶形狀), 엽면(葉面)의 자색(紫色)띠 유무(有無)는 종(種) 특성(特性) 판별(判別)에 유용(有用)할 것으로 판단(判斷)되었다.