• Review of KIISC
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• v.3 no.4
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• pp.63-70
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• 1993

본 논문에서는 n 개의 원소를 임의로 나열하는 대표적인 치환 발생 알고리즘을 소개하고 이들중 발생 치환의 랜덤성이 우수하다고 알려진 Knuth의 알고리즘을 근간으로 설계된 랜덤 치환 발생기의 암호학적 안전성을 분석하고 발생 치환들에 대한 난수 발생 수열 관점의 통계적 임의성과 연속 발생 치환끼리의 통계적 독립성 적용을 위한 통계량 소개 및 각 관점에서 통계적 검정을 통과함을 시뮬레이션 결과를 통하여 보인다.

• Review of KIISC
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• v.3 no.1
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• pp.26-30
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• 1993

본 논문에서는Akl-Meijer가 설계한 랜덤 치환 발생기를 일반화한 알고리즘을 제안한다. Akl과 Meijer는 사이즈가 m인 치환(Permutation)과 0과 m!-1사이의 정수를 일대일 대응시키는 Knuth의 알고리즘을 이용하여, 선형 합동법 Y=X+C mod m! (C는 상수)에서 발생되는 난수와 일대일 대응되는 치환을 발생하는 치환 발생 알고리즘을 설계하였으며, 이를 응용하여, 이진 난수 발생기를 제시하였다. 본 논문에서는 선형 합동법 Y=AX+C mod m!(A, C는 상수)에서 발생되는 난수와 일대일 대응되는 치환 계산과정을 상삼각 행렬(Upper triangular matrix) 의 곱으로 변환하여 고속으로 계산하는 알고리즘을 제시한후, 이 알고리즘의 출력 치환을 n 개 결합하여 치환을 발생하는 랜덤치환 발생기를 설계한다. 또한 이의 암호적인 응용으로, 치환 발생기를 이용한 이진 난수 발생기를 제시한다.

• Korean Journal of Crystallography
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• v.7 no.2
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• pp.165-174
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• 1996

The effects of Ba2+, Sr2+, and Ca2+-substitutions for Pb2+ at Pb(Zr0.52Ti0.48)O3 composition were studied for thier dielictric, piezoelectric, and aging properties. For relative dielectric constants and electromechanical coupling factors, the Ba2+-substituted composition was the highest and the Ca2+-substityed composition was the lowest. In the case of mechanical quality factors, the opposite behavior occurred. Time dependence of frequency for various ion-substituted compositions is similar to that of non-substituted composition. The piezoelectric properties after aging at high temperature was the worse than that after aging at room temperature.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.3
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• pp.90-97
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• 2009

The purpose of the study was to examine basic property at the time of applying cast ('CS' below) and high fineness fine particle cement ('FC' below) as a stimulant to 20% substitution cement mortar of ground granulated blast-furnace slag ('BS' below) to settle a problem that early strength of BS mortar is lowered. The results were as follows. First of all, as a characteristic of fresh mortar, liquidity was reduced as much as BS substitution rate was increased. When substituting CS for BS 20%, it didn't have a large effect regardless of substitution rate. When substituting FC, it was reduced as much as substitution was increased. In the event of compressive strength, it was reduced as much as BS substitution was increased in early age. In age 28, it was somewhat increased by reflection of potential hydraulicity. With regard to improvement of early compressive/bending strength of BS 20% substitution mortar, when substituting CS, in early age, they were a little increased as much as addition rate was increased. When substituting FC, in early and 28 age, they were largely increased as much as substitution rate was increased. To settle a problem that early strength of BS 20% substitution mortar was lowered, CS substitution has a little effect and FC 25% substitution was similar to plain with only OPC. Therefore, when substituting FC 25%, it is expected that its quality will be improved.

• Clinics in Shoulder and Elbow
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• v.14 no.1
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• pp.111-116
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• 2011

Purpose: The purposes of this article are to review the mid-term results and the complications after reverse total shoulder arthroplasty and to analyze the influence of the etiology on the result. Materials and Methods: We conducted a systemic review of the published literature with the mid-term follow-up after reverse total shoulder arthroplasty was performed. The overall rates of problems, complications, reoperations and revisions were determined. Results: The reported complication rates varied from 0% to 68%. The first series of reverse prosthesis with at least 2 yrs of follow-up confirmed the preliminary results, with excellent functional outcomes. However, a systemic review of the published literature with a mid-term follow-up showed problems in 44% of the cases, complications in 24% of the cases, reoperations in 3.5% of the cases and revision in 10% of the cases. Conclusion: Reverse total shoulder arthroplasty has relatively high complication and revision rates. So, a reverse prosthesis should be used in patients with very disabling arthropathy and a massive cuff tear and who are over seventy (at least sixty-five) years old.

• Journal of the Korean Chemical Society
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• v.44 no.3
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• pp.184-189
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• 2000

ab initio molecular orbitaI calculation is performed to estimate the substituent effects for meta-substituted pyridines. Electrostatic potentials are obtained from ab initio wavefunctions of the optimized structures for the meta-substituted pyridines. Electrostatic potenhals are shown to be minimum at nitrogen atom of pyridines. The potenttial minima are good correlated with the substituent constants, ${\sigma}_m$ and with the ${\Delta}pK_a$, respectively. It is found that the electrostatic potential minima can be used as a useful measure of substituent effects.

• Korean Journal of Environment and Ecology
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• v.13 no.1
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• pp.89-95
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• 1999

본 연구는 임해매립지에서 토양의 화학적 특성을 조사하여 수목식재를 위한 합리적인 토양관리에 관한 자료를 얻고자 수행하였다. 토양조사는 시화매립지의 시흥공단에서 녹지조성 예정지를 중심으로 토지이용별 및 토심별로 실시되었다. 조사지역에서 개흙은 전기전도도와 치환성나트륨 백분율이 높은 염류알칼리성 토양 특징을 갖고있었다. 임해매립지에서 토양 pH 평균값은 7.8~5.7범위이었고, 주거/공단 완충녹지 토양에서 전기전도도와 치환성나트륨 백분율은 각각 3.76Sm-1와 35%로 조사지역 중에 가장 높았다. 토양 50cm 깊이에서 치환성 Na+의 평균함량은 1.76~2.80cmol+/kg으로 조사되었고, 치환성 Na+의 평균함량은 치환성 Ca2+보다는 낮았으나 치환성 Mg2+과 K+보다는 높았다. 토심별 염분농도는 50cm보다 100cm 깊이에서 높게 조사되었으며, 주거/공단 완충녹지는 전토심에서 염분농도가 수목에 영향을 주기에 충분할 정도로 높았다.

• Journal of the Korean Chemical Society
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• v.43 no.4
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• pp.378-383
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• 1999

Ab initio calculation is performed to estimate the substituent effects for Para-substituted pyridines. Electrostatic potentials are obtained from ab initio molecular orbital wavefunctions of optimized structures for substituted pyridines. Electrostatic potentials are computed to be minimum at nitrogen atom of pyridines. The potential minima are good correlated with the substituent constants, ${\sigma}_p$ and with the ${\Delta}pKa$. It is shown that the electrostatic potential minima can be used as a measure of substituent effects.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.280-284
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• 2016

본 연구에서는 Density functional theory(DFT) 계산을 이용하여, $MoS_2$의 Mo와 S를 다른 원자로 치환 했을 때 $2H-MoS_2$ monolayer의 basal plane에서 HER활성을 향상시켰다. 특히 Ge와 Rh를 치환한 경우, ${\Delta}G_H$가 각각 0.03eV, 0,07eV로 최적에 가까운 HER활성이 나타났다. 다른 원자의 치환이 Fermi level 근처의 DOS(density of states)를 높여, ${\Delta}G_H$을 0에 가깝게 낮출 수 있음을 확인하였다. 또한 치환되는 원자의 농도, 그리고 strain을 변화시켜 농도와 strain의 증가에 따른 ${\Delta}G_H$ 감소를 발견했다. 이로써 각치환되는 원자마다, 치환 농도와 strain을 함께 변화시켜 ${\Delta}G_H$을 낮출 수 있었다. ${\Delta}G_H$가 0에 가까운(${\pm}{\pm}0.2eV$ 이내) 원자종류, 치환 농도, strain의 여러 조합을 찾았다.

• Journal of Chest Surgery
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• v.40 no.6 s.275
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• pp.414-419
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• 2007

Background: Replacing the ascending aorta is a standard surgical option for treating acute type A aortic dissection. But replacing the aortic arch has recently been reported as an acceptable procedure for this disease. We compared the effects of aortic arch replacement for treating acute type A aortic dissection with the effects of ascending aortic replacement. Material and Method: From 2002 to 2006, 25 patients undewent surgical treatment for acute type A aortic dissection, 12 patients undewent ascending aortic replacement and 13 patients underwent aortic arch replacement. Among the aortic arch group, an additional distal stent-graft was inserted during the operation in 5 patients. 19 patients (11 arch replaced patients and 8 ascending aortic replaced patients) were followed up at the out patient clinic for an average of $756{\pm}373$ days. All the patients undewent CT scanning and we analyzed their distal aortic segments. Result: 4 patients who underwent ascending aortic replacement died, so the overall mortality rate was 16%. Among the 11 long term followed-up arch replacement patients, 2 patients (18.1 %) developed distal aortic dilatation and one of them underwent thoracoabdominal aortic replacement later on. However, among the 8 the ascending aortic replaced patients, 5 patients (62.5%) developed distal aortic dilatation. Conclusion: Aortic arch replacement is one of the safe options for treating acute type A aortic dissection. Aortic arch replacement for treating acute type A aortic dissection could contribute to a reduced distal aortic dilatation rate and fewer secondary aortic procedures.