Y-doped BaZrO₃에서의 산소 공공과 프로톤의 이동

김대희,정용찬,박종성,김병국,김영철,Kim, Dae-Hee,Jeong, Yong-Chan,Park, Jong-Sung,Kim, Byung-Kook,Kim, Yeong-Cheol 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.6

We studied the transfer of oxygen vacancy and proton in Y-doped BaZr$O_3$ (BYZ) using density functional theory (DFT). An oxygen vacancy was generated in the $2{\times}2{\times}2$ BYZ superstructure by replacing two Zr atoms with two Y atoms to satisfy the charge neutrality condition. The O vacancy transfer between the first and second nearest O atom sites from a Y atom showed the lowest activation energy barrier of 0.42 eV, compared to the other transfers between first and first, and second and second in the superstructure. Two protons were inserted in the structure by adding a proton and hydroxyl that were supplied by the dissociation of a water molecule. The two protons bonded to the first and second nearest O atoms were energetically the most favorable. The activation energy barrier for a proton transfer in the structure was 0.51 eV, when either proton transferred to its neighbor O atom. This value was well matched with the experimentally determined one.

Orthorhombic-NiSi/Si (010) 구조의 Pd 치환 연구: 제 1 원리 계산

김대희,김대현,서화일,김영철,Kim, Dae-Hee,Kim, Dae-Hyun,Seo, Hwa-Il,Kim, Yeong-Cheol 한국반도체디스플레이기술학회 2008 반도체디스플레이기술학회지 Vol.7 No.4

NiSi is less stable than the previously-used $CoSi_2$ at high temperature. Some noble metals, such as Pd and Pt, have been added to NiSi to improve its thermal stability. We employed a first principles calculation to understand the Pd segregation at the interface. An orthorhombic structure of NiSi was used to construct an orthorhombic-NiSi/Si (010). Lattice parameters along a- and c-axes in orthorhombic-NiSi were matched with those of Si for epitaxy contact. The optimized $1\times4\times1$ orthorhombic-NiSi (010) and $1\times2\times1$ Si (010) superstructures were put together to construct the orthorhombic-NiSi/Si (010), and the superstructure was relieved in calculation to minimize its total free energy. The optimized interface thickness of the superstructure was $1.59\AA$. Pd atom was substituted in Ni and Si sites located near interface. Both Ni and Si sites located at the interface were favorable for Pd substitution.

화상 환자에서 신속 순차 시각 제시를 이용한 주의깜빡임에 관한 예비연구

김대희,전보라,서정훈,조용석,임해준,허준,김도헌,전욱,김종현,정명훈,최인근,이병철,Kim, Dae Hee,Jun, Bora,Seo, Cheong Hoon,Cho, Yongsuk,Yim, Haejun,Hur, Jun,Kim, Dohern,Chun, Wook,Kim, Jonghyun,Jung, Myung Hun,Choi, Ihngeun,Lee, Boung Ch 대한생물정신의학회 2010 생물정신의학 Vol.17 No.2

Objectives : Trauma patients have attentional bias which enforces traumatic memories and causes cognitive errors. Understanding of such selective attention may explain many aspects of the posttraumatic stress disorder(PTSD) symptoms. Methods : We used the rapid serial visual presentation(RSVP) method to verify attentional blink in burn patients with PTSD. International affective picture system(IAPS) was used as stimuli and distracters. In the 'neutral test', patients have been presented series of pictures with human face picture as target stimuli. Each picture had 100ms interval. However the distance between target facial pictures was randomized and recognition of second facial picture accuracy was measured. In the 'stress test', the first target was stress picture which arouses patient emotions instead of the facial picture. Neutral and Stress tests were done with seven PTSD patients and 20 controls. In '85ms test' the interval was reduced to 85ms. The accuracy of recognition of second target facial picture was rated in all three tests. Eighty-five ms study was done with eighteen PTSD patients. Results : Attentional blinks were observed in 100-400ms of RSVP. PTSD patients showed increased recognition rate in the 'stress test' compared with the 'neutral test'. When presentation interval was decreased to 85 ms, PTSD patient showed decrease of attentional blink effect when target facial picture interval was 170ms. Conclusion : We found attentional blink effect could be affected by stress stimulus in burn patients. And attentional blink may be affected by stimulus interval and the character of stimulus. There may be some other specific mechanism related with selective attention in attentional blink especially with facial picture processing.

밀도범함수를 이용한 정방정계-NiSi (010)/Si 계면 층의 구조 연구

김대희,김대현,서화일,김영철,Kim, Dae-Hee,Kim, Dae-Hyun,Seo, Hwa-Il,Kim, Yeong-Cheol 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.5

Tetragonal-NiSi (010)/Si superstructures were calculated for studying the interface structure using density functional theory, The orthorhombic-NiSi was changed to the tetragonal-NiSi to be matched with the Si surface for epitaxy interface. The eight interface models were produced by the type of the Si surfaces, The tetragonal-NiSi (010)/Si (020)[00-1] superstructure was energetically the most favorable, and the interface thickness of this superstructure was the shortest among the tetragonal-NiSi (010)/Si superstructures. However, in the case of tetragonal-NiSi (010)/Si (010)[00-1] superstructure, it was energetically the most unfavorable, and the interface thickness was the longest. The energies and interface thicknesses of tetragonal-NiSi (010)/Si superstructures were influenced by the coordination number of Ni atoms and the bond length between atoms located at the interface.

방추리(경기도, 이천시)의 거미상

김주필(Joo Pil Kim),김대희(Dae Hee Kim) 한국거미연구소 2017 한국거미 Vol.33 No.2

2013년 10월 20일부터 2017년 8월 6일까지 경기도 이천시 장호원읍 방추리 일대를 한국거미연구회 회원 김대희가 채집한 결과, 총 20과 44속 57종이 조사 연구되어 이에 발표하는 바이다. 채집한 표본은 주필거미박물관에 보관하였다. From October 20 2013 to August 6 2017, Kim Dae-hee, the member of The Arachnological Institute of Korea, collected the spiders in the whole area of Bangchu-ri, and reports 20 families, 44 genera 57 species of spiders. The collected spiders are placed in the Joo-Pil Spider museum in Namyangju-si, Gyeonggi-do.

재오개리(충청북도, 충주시)의 거미상

김주필(Joo Pil Kim),김대희(Dae Hee Kim) 한국거미연구소 2017 한국거미 Vol.33 No.2

2014년 5월 4일부터 2017년 8월 5일까지 충청북도 충주시 살미면 재오개리 일대를 한국거미연구회 회원 김대희가 주야로 채집한 결과, 총 18과 43속 47종이 조사 연구되어 이에 발표하는 바이다. 채집한 표본은 주필거미박물관에 보관되어있다. From May 4 2014 to August 5 2017, collected spiders of 18 families 43 Genera 47 species from Jaeogae-ri, Salml-myeon, Chungju-si, Chungcheongbuk-do. The result of investigation is reported by Dae-Hee Kim, the member of Arachnological Institute of Korea. The specimens of those spiders are placed in the Joo-Pil Spider Museum.

독사 교상 후 초기 증상 지연재평가의 임상적 중요성

김대희,최세민,오영민,오주석,경연영,최경호,Kim, Dae-Hee,Choe, Se-Min,Oh, Young-Min,Oh, Joo-Suk,Kyong, Yeon-Young,Choi, Kyoung-Ho 대한임상독성학회 2009 대한임상독성학회지 Vol.7 No.2

Purpose: Antivenin is a standard therapy in snakebite victims. While the required antivenin dose can be easily estimated, based on the initial symptoms, this strategy may be unsuccessful if the initial symptoms progressively worsen. The purpose of this study was to identify the progression rate of the initial symptoms following snakebite and its associated factors. Methods: The medical records of 44 patients treated for snakebite from give the actual dates of the study period were retrospectively examined. Thirty-two of these patients were enrolled. Demographic data, local wound grade and local effect score at initial presentation (G-0 and LES-0, respectively) and 12 hours after admission (G-12 and LES-12, respectively) were reviewed, along with laboratory data. Results: The 32 patients had an average age of $54.0{\pm}14.5$ years and were predominantly male (n=26) and presented mainly during summer. Compared to G-0 and LES-0, re-evaluated G-12 and LES-12 were significantly increased despite initial administration of proper antivenin dosage (p=0.001 and p=0.000, respectively). Total amounts of antivenin correlated with LES-12 (correlation co-efficiency 0.558, p<0.05). However, factors associated with symptom progression were not revealed. Conclusion: Initial snakebite symptoms might progressively worsen within hours despite acceptable initial antivenin therapy. Therefore, re-evaluation within several hours must be considered if when the initial snakebite symptoms are minimal or mild.

레이저 조사 방법이 Nd:YAG 레이저 경공막 모양체 광응고술의 결과에 미치는 영향

김대희,양홍석,유호민,안재홍,Dae Hee Kim,Hong Seok Yang,Ho Min Lew,Jae Hong Ahn 대한안과학회 2010 대한안과학회지 Vol.51 No.7

Purpose: To examine the influence of irradiation methods on the long-term results of contact transscleral Nd:YAG laser cyclophotocoagulation and to evaluate the factors that affect changes in intraocular pressure (IOP) and occurrence of ocular hypotony after cyclophotocoagulation. Methods: In this retrospective study, 36 refractory glaucomatous eyes of 36 patients were observed for at least one year after a cyclophotocoagulation procedure. Contact transscleral Nd:YAG laser cyclophotocoagulation was performed with 7 to 10 Watts of power, a duration of 0.7 seconds, with one or two rows, and ranges of either greater or less than 180 degrees. The change in IOP, the success rate of the procedure, and the occurrence rate of hypotony were analyzed with regard to the methods of cyclophotocoagulation. Results: In this series of patients with refractory glaucoma, the final IOP and success rate were not significantly influenced by the laser application method or by the total energy used. The eyes with ocular hypotony showed significantly decreased IOP one year after cyclophotocoagulation when compared with eyes without ocular hypotony. The IOP percent reduction in the patients with ocular hypotony tended to decrease more rapidly than did that of the patients without hypotony, beginning three months after the operation. Conclusions: The application methods of cyclophotocoagulation appear to have no significant influence on success rate, IOP or ocular hypotony rate. The percent reduction in IOP was higher in the hypotony group, including during the early postoperative periods.

ZnO 박막 성장을 위한 Zn 전구체와 Si (001) 표면과의 초기 반응

김대희,이가원,김영철,Kim, Dae-Hee,Lee, Ga-Won,Kim, Yeong-Cheol 한국재료학회 2010 한국재료학회지 Vol.20 No.9

We studied the initial reaction mechanism of Zn precursors, namely, di-methylzinc ($Zn(CH_3)_2$, DMZ) and diethylzinc ($Zn(C_2H_5)_2$, DEZ), for zinc oxide thin-film growth on a Si (001) surface using density functional theory. We calculated the migration and reaction energy barriers for DMZ and DEZ on a fully hydroxylized Si (001) surface. The Zn atom of DMZ or DEZ was adsorbed on an O atom of a hydroxyl (-OH) due to the lone pair electrons of the O atom on the Si (001) surface. The adsorbed DMZ or DEZ migrated to all available surface sites, and rotated on the O atom with low energy barriers in the range of 0.00-0.13 eV. We considered the DMZ or DEZ reaction at all available surface sites. The rotated and migrated DMZs reacted with the nearest -OH to produce a uni-methylzinc ($-ZnCH_3$, UMZ) group and methane ($CH_4$) with energy barriers in the range of 0.53-0.78 eV. In the case of the DEZs, smaller energy barriers in the range of 0.21-0.35 eV were needed for its reaction to produce a uni-ethylzinc ($-ZnC_2H_5$, UEZ) group and ethane ($C_2H_6$). Therefore, DEZ is preferred to DMZ due to its lower energy barrier for the surface reaction.

원자로건물의 철근콘크리트 전단벽 비선형 지진응답 평가

김대희,이경구,구지모,Kim, Dae Hee,Lee, Kyung Koo,Koo, Ji Mo 한국전산구조공학회 2021 전산구조공학 Vol.34 No.6

Interest in the seismic performance of nuclear facilities under strong earthquakes has increased because their nonlinear response is important. In this paper, we proposed appropriate parameters for the nonlinear finite element analysis of a concrete material model, for a reinforced concrete (RC) shear wall in nuclear facilities: maximum tensile strength, dilation angle, and damage parameter. The study of the effects of the important parameters, on the nonlinear behavior and shear failure mode of the RC shear wall having low aspect ratio, was conducted using ABAQUS finite element analysis program. Based on the study results the nonlinear response of a nuclear reactor containment building (RCB) subjected to a strong earthquake was evaluated using nonlinear time-history analysis. 강진 시 원자력발전시설의 비선형 응답이 중요하기 때문에 이 시설의 내진성능에 대한 관심이 증가하였다. 이 연구에서는 원자력 발전소 철근콘크리트 전단벽의 유한요소해석을 위한 재료모델의 적절한 변수를 제시하였다: 최대인장강도, 팽창각, 손상계수. 이를 위해 상용 유한요소 해석프로그램인 ABAQUS를 사용하여 낮은 형상비를 가진 철근콘크리트 전단벽의 비선형 거동과 전단 파괴모드에 대한 이 주요 변수의 효과에 대한 연구를 수행하였다. 연구결과에 기반하여 비선형 시간이력해석을 통해 강진 하의 원자로건물의 비선형 응답을 평가하였다.