• 한국정보전자통신기술학회논문지
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• 제16권4호
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• pp.180-186
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• 2023

본 논문은 4세대 VNAND 공정으로 만들어진 고전압 SiO2 절연층 nMOSFET의 n⁺ 및 p⁺ poly-Si 게이트에서의 positive bias temperature instability(PBTI) 열화에 대해 비교하고 각각의 메커니즘에 대해 분석한다. 게이트 전극 물질의 차이로 인한 절연층의 전계 차이 때문에 n⁺/nMOSFET의 열화가 p⁺/nMOSFET의 열화보다 더 클 것이라는 예상과 다르게 오히려 p⁺/nMOSFET의 열화가 더 크게 측정되었다. 원인을 분석하기 위해 각각의 경우에 대해 interface state와 oxide charge를 각각 추출하였고, 캐리어 분리 기법으로 전하의 주입과 포획 메커니즘을 분석하였다. 그 결과, p⁺ poly-Si 게이트에 의한 정공 주입 및 포획이 p⁺/nMOSFET의 열화를 가속시킴을 확인하였다.

• Journal of applied mathematics & informatics
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• 제40권5_6호
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• pp.1181-1198
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• 2022

In this paper we are concerned with the number of fuzzy subgroups of a finite abelian p-group ℤ_p^m × ℤ_pⁿ × ℤ_p^ℓ of rank three with order p^m+n+ℓ. We obtain a recurrence relation for the number of fuzzy subgroups of a finite abelian p-group ℤ_p^m × ℤ_pⁿ × ℤ_p^ℓ. In order to show that using this recurrence relation, one can find explicit formulas for the number of fuzzy subgroups of ℤ_p^m × ℤ_pⁿ × ℤ_p^ℓ consecutively, we give explicit formulas for the number of fuzzy subgroups of ℤ_p^m × ℤ_pⁿ × ℤ_p^ℓ where (n, ℓ) = (1, 1), (2, 1), (3, 1), (4, 1), (5, 1), (2, 2), (3, 2), (4, 2), (5, 2).

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.640-647
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• 2023

Material corrosion in nuclear power plant (NPP) is not controlled only by amine injection but also by ion exchange (IX) which is the best option to remove trace Na⁺. This study was conducted to understand the Na⁺ leakage characteristics of IX beds packed with ethanolamine-form (ETAH-form) and hydrogen-form (H-form) resins in the simulated water-steam cycle in terms of intrinsic behaviors of four kinds of cation-exchange resins through ASTM test and Vanselow mass action modeling. Na⁺ was inappreciably escaped throughout the channel created in resin layer. Na⁺ leakage from IX bed was non-linearly raised because of its decreasing selectivity with increasing Na⁺ capture and with increasing the fraction of ETAH-form resin. Na⁺ did not reach the breakthrough earlier than ETAH⁺ and NH₄⁺ due to the increased selectivity of Na⁺ to the cation-exchange resin (H⁺ < ETAH⁺ < NH₄⁺ ≪ Na⁺) at the feed composition. Na⁺ leakage from the resin bed filled with small particles was decreased due to the enhanced dynamic IX processes, regardless of its low selectivity. Thus, the particle size is a predominant factor among intrinsic properties of IX resin to reduce Na⁺ leakage from the condensate polishing plant (CPP) in NPPs.

• 대한수학회보
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• 제59권5호
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• pp.1255-1268
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• 2022

We consider the Schrödinger type operator 𝓛 = (-𝚫_ℍⁿ)² + V² on the Heisenberg group ℍⁿ, where 𝚫_ℍⁿ is the sub-Laplacian and the non-negative potential V belongs to the reverse Hölder class RH_s for s ≥ Q/2 and Q ≥ 6. We shall establish the (L^p, L^q) estimates for the Riesz transforms T_𝛼,𝛽,j = V^2𝛼𝛁^j_ℍⁿ𝓛^-𝛽, j = 0, 1, 2, 3, where 𝛁_ℍⁿ is the gradient operator on ℍⁿ, 0 < α ≤ 1-j/4, j/4 < 𝛽 ≤ 1, and 𝛽 - 𝛼 ≥ j/4.

• 분석과학
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• 제29권4호
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• pp.170-178
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• 2016

팔중극자 반응셀을 장착한 사중극자 유도결합플라즈마 질량분광기에서 동위원소 희석법을 사용하여 셀레늄을 분석할 때에 여러 다른 스파이크 동위원소들 ⁷⁶Se, ⁷⁷Se, 및 ⁷⁸Se에 대한 정확도와 정밀도를 비교하였다. 무기 셀레늄 표준용액에 대한 분석결과, ID분석법의 정확도는 매일의 결과는 물론 장기간(세 달간)에도 세 개의 스파이크 모두 1 % 이내의 오차만을 보여주었고 %RSD도 1 % 수준이었다. 동위원소 스파이크 ⁷⁶Se, ⁷⁷Se 은 그 결과값은 비슷하며 ⁷⁸Se이 조금 더 나은 결과를 보여주었다. 하지만 실제시료인 기준물질 NIST SRM 1568a(쌀분말)과 NIST SRM 2967(홍합)에서는 사용하는 스파이크 동위원소에 따라 서로 다른 정확도와 정밀도를 보여주는데 가장 큰 이유는 측정 및 계산에 사용된 m/z에 대한 서로 다른 여러 간섭 때문으로 나타났다. ORC사용으로 인한 SeH의 생성때문에 나타나는 간섭을 보정한 뒤 매트릭스에 포함된 Br, As에 의한 간섭에 대한 보정을 하였다. 결과, 비교적 간단한 매트릭스를 가진 쌀분말일 때 ⁷⁶Se, ⁷⁷Se, 및 ⁷⁸Se은 서로 비슷한 결과를 얻었으며 각 각 80% 정도의 회수율을 꾸준하게 보여주었다. 정밀도는 ⁷⁸Se의 경우에는 1.8% RSD로서 무기표준물의 경우와 비슷하다. ⁷⁶Se와 ⁷⁷Se는 각 각 8.6%, 6.3% RSD로서 약간 높지만 전체적으로 이 실험은 신뢰할 수 있다고 보인다. 매트릭스가 복잡한 홍합의 경우에도 ⁷⁶Se와 ⁷⁷Se는 오차가 5 % 이내로서 정확한 결과를 보여주나 정밀도는 RSD 15 % 수준으로 조금 높은 편이다. 하지만 ⁷⁸Se의 경우에는 정확도도 나쁘지만 정밀도가 매우 나빠서(100% 이상의 RSD) 신뢰할 수 없는 결과를 보여준다. 이 는 ⁷⁸Se의 경우, 워낙 Br의 간섭이 크기 때문으로 비록 수학적 보정을 한다하여도 충분하지 않음을 보여준다. 따라서 스파이크 동위원소를 선택할 때에는 매트릭스가 간단하다면 신호가 높은 ⁷⁸Se동위원소를 선택하는 것이 조금 더 유리할 수 있지만 Br이나 간섭이 많을 때는 ⁷⁸Se은 피하고 ⁷⁶Se이나 ⁷⁷Se을 선택하여야 하며 이 경우 충분히 좋은 결과를 보여줄 수 있다.

• 공업화학
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• 제30권6호
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• pp.737-741
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• 2019

본 연구에서는 스크린 프린팅 공정을 이용하여 저렴하고 유연한 칼륨 이온(K⁺) 센서를 제작하였다. 전도성 잉크의 균일한 코팅은 주사 전자 현미경 및 광학 현미경 측정에 의해 입증되었다. K⁺ 센서는 높은 감도, 빠른 응답 시간, 낮은 검출 한계를 보여주었다. 제조된 K⁺ 센서의 감도는 기계적으로 구부러진 상태에도 여전히 유지되었다. 히스테리시스 효과가 없는 우수한 반복성과 우수한 장기 안정성이 K⁺ 센서의 전기화학적 특성 분석에서 관찰되었다. 또한, K⁺ 센서는 다른 간섭 양이온이 존재하는 경우에도 정확하게 K⁺ 농도를 측정 할 수 있어 우수한 선택성을 증명하였다. 또한, 실제 스포츠 음료 샘플에서 K⁺ 농도의 성공적인 측정은 K⁺ 센서의 K⁺ 농도 값과 상용 K⁺ 미터를 비교하여 증명되었다.

• 대한정형도수물리치료학회지
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• 제29권1호
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• pp.25-31
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• 2023

Background: In this study, the abductor hallucis activity and medial longitudinal arch angle were compared by performing four exercises, namely the short foot exercise, the short foot exercise with 2^nd~5^th toe extension, the short foot exercise with 2^nd~5^th toe extension with a load of 1kt on the sole, and the short foot exercise with 2^nd~5^th toe extension with a load of 2kg on the sole. Methods: Four short foot exercises as described above were performed by 20 healthy adult males and females. The abductor hallucis activity and medial longitudinal arch angle were measured and analyzed by surface electromyography and the Kinovea software program. Results: The short foot exercise with 2^nd~5^th toe extension, short foot exercise with 2^nd~5^th toe extension with a load of 1kg on the sole, and the short foot exercise with 2^nd~5^th toe extension with a load of 2kg on the sole showed significantly higher abductor hallucis activity than the short foot exercise alone. Among these, the short foot exercise with the 2^nd~5^th toe extension was the most effective. All exercises showed a significantly decreased medial longitudinal arch angle post-exercise than pre-exercise, and the short foot exercise with the 2^nd~5^th toe extension showed a significantly decreased medial longitudinal arch angle compared to the other three exercises. Conclusion: It is believed that the short foot exercise with the 2^nd~5^th toe extension can be proposed as an effective exercise that can replace the short foot exercise alone.

• 한국표면공학회지
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• 제56권3호
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• pp.201-207
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• 2023

Eu³⁺-doped SnO² (SnO²:Eu³⁺) phosphor thin films were grown on quartz substrates by radio-frequency magnetron sputtering. The deposition temperature was varied from 100 to 400 ℃. The X-ray diffraction patterns showed that all the thin films had two mixed phases of SnO₂ and Eu₂Sn₂O₇. The 880 nmthick SnO²:Eu³⁺ thin film grown at 100 ℃ exhibited numerous pebble-shaped particles. The excitation spectra of SnO²:Eu³⁺ thin films consisted of a strong and broad peak at 312 nm in the vicinity from 250 to 350 nm owing to the O^2--Eu3+ charge transfer band, irrespective of deposition temperature. Upon 312 nm excitation, the SnO²:Eu³⁺ thin films showed a main emission peak at 592 nm arising from the ⁵D₀→⁷F₁ transition and a weak 615 nm red band originating from the ⁵D₀→⁷F₂ transition of Eu³⁺. As the deposition temperature increased, the emission intensities of two bands increased rapidly, approached a maximum at 100 ℃, and then decreased slowly at 400 ℃. The thin film deposited at 200 ℃ exhibited a band gap energy of 3.81 eV and an average transmittance of 73.7% in the wavelength range of 500-1100 nm. These results indicate that the luminescent intensity of SnO²:Eu³⁺ thin films can be controlled by changing the deposition temperature.

• The Journal of Advanced Prosthodontics
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• 제15권3호
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• pp.114-125
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• 2023

PURPOSE. The aim of the study was to evaluate the optical properties of new generation (3Y-TZP) monolithic zirconia (MZ) with different abutment types and resin cement shades. MATERIALS AND METHODS. A1/LT MZ specimens were prepared (10 × 12 × 1 mm, N = 30) and divided into 3 groups according to cement shades as transparent (Tr), yellow (Y) and opaque (O). Abutment specimens were obtained from 4 different materials including zirconia (Group Z), hybrid (Group H), titanium (Group T) and anodized yellow titanium (Group AT). MZ and abutment specimens were then cemented. L^*, a^*, and b^* parameters were obtained from MZ, MZ + abutment, and MZ + abutment + cement. ∆E₀₀₁^* (between MZ and MZ + abutment), ∆E₀₀₂^* (between MZ and MZ + abutment + cement) and ∆E₀₀₃^* (between MZ + abutment and MZ + abutment + cement) values were calculated. Statistical analyses included 2-way ANOVA, Bonferroni, and Paired Sample t-Tests (P < .05). RESULTS. Abutment types and resin cements had significant effect on L^*, a^*, b^*, ∆E₀₀₁^*, ∆E₀₀₂^*, and ∆E₀₀₃^* values (P < .001). Without cementation, whereas zirconia abutment resulted in the least discoloration (∆E₀₀₁^* = 0.68), titanium abutment caused the most discoloration (∆E₀₀₁^* = 4.99). The least ∆E₀₀₂^* = 0.68 value was seen using zirconia abutment after cementation with yellow shaded cement. Opaque shaded cement caused the most color change (∆E₀₀₃^* = 5.24). Cement application increased the L^* values in all groups. CONCLUSION. The least color change with/without cement was observed in crown configurations created with zirconia abutments. Zirconia and hybrid abutments produced significantly lower ∆E₀₀₂^* and ∆E₀₀₃^* values in combination with yellow shaded cement. The usage of opaque shaded cement in titanium/anodized titanium groups may enable the clinically unacceptable ∆E₀₀^* value to reach the acceptable level.

• Nuclear Engineering and Technology
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• 제55권7호
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• pp.2388-2394
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• 2023

The radioactivity concentration of environmental radionuclides was analyzed for soil and sand at eight locations within a radius of 255 m centered on the Dongnam Institute of Radiological & Medical Science (DIRAMS), Korea. The average activity concentrations of ⁴⁰K, ¹³⁷Cs, ²²⁶Ra, and ²³²Th were 661.1 Bq/kg-dry, 0.9 Bq/kg-dry, 21.9 Bq/kg-dry, and 11.1 Bq/kg-dry, respectively. The activity of ⁴⁰K and ¹³⁷Cs was lower than the 3-year (2017-2019) average reported by the Korea Institute of Nuclear Safety, respectively. Due to the nature of granite-rich soil, the radioactivity of ⁴⁰K was 0.6-fold higher than in other countries, while ¹³⁷Cs was in the normal fluctuation range (15-30 Bq/kg-dry) of the concentration of radioactive fallout from nuclear tests. The activity of ²²⁶Ra and ²³²Th was lower than in Korean soils reported by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The average activity concentrations of ²³²Th and ⁴⁰K for the soil and sand samples from DIRAMS were within the range specified by UNSCEAR in 2000. The radium equivalent activity and internal and external hazard index values were below the recommended limits (1 mSv/y). These radionuclide concentration (²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs) data can be used for regional environmental monitoring and ecological impact assessments of nuclear power plant accidents.