• 제목/요약/키워드: MO theoretical study

검색결과 128건 처리시간 0.027초

Social Adjustment of Adolescent Cancer Survivors: A Concept Analysis

  • Oh, Su-Mi;Lee, Hyejung;Kim, Sue;Kim, Sanghee;Lyu, Chuhl Joo
    • Child Health Nursing Research
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    • 제25권3호
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    • pp.290-302
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    • 2019
  • Purpose: This study aimed to identify the attributes of social adjustment among adolescent cancer survivors using concept analysis and to propose a definition of the concept. Methods: In accordance with the hybrid model of concept analysis, this study employed a three-phase circular process comprising theoretical, fieldwork, and final analysis phases. A thorough literature review was conducted using MEDLINE, Embase, and Korean databases, followed by qualitative fieldwork with seven participants. The results derived from the theoretical and fieldwork phases were integrated into the final analysis phase. Results: Four attributes of social adjustment were found in adolescent cancer survivors: having harmonious relationships with friends, having harmonious relationships with boy/girlfriends, fulfilling their present roles, and planning for and expecting future roles. The following definition of social adjustment of adolescent cancer survivors is proposed: "the conquering of difficulties arising from the continuum of childhood cancer and the achievement of the developmental tasks of typical adolescents." Conclusion: Social adjustment of childhood cancer survivors is crucial for integrating them into society. The findings of this study provide a basis for developing an instrument to measure the social adjustment of adolescent cancer survivors and for developing of interventions that target this group.

에너지 전자상태 계산으로 도출된 이론값을 이용한 니켈 합금 설계 (Design of Nickel Alloys Using the Theoretical Values Calculated from the Electronic State Energies)

  • 백민숙;강법성;백경철;김병일;윤동주
    • 한국재료학회지
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    • 제25권11호
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    • pp.642-646
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    • 2015
  • Super alloys, which can be divided into three categories, i.e. Ni-base, Co-base, and Fe-base alloys, are widely used for high temperature applications. Since superalloys contain many alloying elements and precipitates, their chemistry and processing parameters need to be carefully designed. In this study, we designed a new Ni alloy to prevent corrosion due to water vapor and gases at high temperatures. The new alloy was designed using the theoretical value of the resulting energy electronic state calculation($DV-X{\alpha}$ method). The components that were finally used were Cr, Mo, and Ti, with Ni as a base. For these alloys, elements were selected in order to compare their values with that of the average theoretical basis for an Inconel 625 alloy. Finally, two kinds of Ni alloy were designed: Ni-28Cr-4Mo-2Ti and Ni-20Cr-10Mo-1Ti.

다목적 시뮬레이션 통합 하이브리드 유전자 알고리즘을 사용한 수동 조립라인의 동기 작업 모델 (A Synchronized Job Assignment Model for Manual Assembly Lines Using Multi-Objective Simulation Integrated Hybrid Genetic Algorithm (MO-SHGA))

  • 무하마드 임란;강창욱
    • 산업경영시스템학회지
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    • 제40권4호
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    • pp.211-220
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    • 2017
  • The application of the theoretical model to real assembly lines has been one of the biggest challenges for researchers and industrial engineers. There should be some realistic approach to achieve the conflicting objectives on real systems. Therefore, in this paper, a model is developed to synchronize a real system (A discrete event simulation model) with a theoretical model (An optimization model). This synchronization will enable the realistic optimization of systems. A job assignment model of the assembly line is formulated for the evaluation of proposed realistic optimization to achieve multiple conflicting objectives. The objectives, fluctuation in cycle time, throughput, labor cost, energy cost, teamwork and deviation in the skill level of operators have been modeled mathematically. To solve the formulated mathematical model, a multi-objective simulation integrated hybrid genetic algorithm (MO-SHGA) is proposed. In MO-SHGA each individual in each population acts as an input scenario of simulation. Also, it is very difficult to assign weights to the objective function in the traditional multi-objective GA because of pareto fronts. Therefore, we have proposed a probabilistic based linearization and multi-objective to single objective conversion method at population evolution phase. The performance of MO-SHGA is evaluated with the standard multi-objective genetic algorithm (MO-GA) with both deterministic and stochastic data settings. A case study of the goalkeeping gloves assembly line is also presented as a numerical example which is solved using MO-SHGA and MO-GA. The proposed research is useful for the development of synchronized human based assembly lines for real time monitoring, optimization, and control.

Cr-Mo강의 수소확산 특성에 관한 유한요소해석 (The Finite Element Analysis on the Characteristics of the Hydrogen Diffusion for the Cr-Mo Steels)

  • 이휘원;하민수
    • 한국기계기술학회지
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    • 제13권2호
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    • pp.115-121
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    • 2011
  • The size of hydrogen molecule is not so small as to invade into the lattice of material, and therefore, hydrogen invades into the material as atom. Hydrogen movement is done by diffusion or dislocation movement in the near crack tip or plastic deformation. Hydrogen appeared to have many effects on the mechanical properties of the Cr-Mo steel alloys. The materials for this study are 1.25Cr-0.5Mo and 2.25Cr-1Mo steels used at high temperature and pressure. The hydrogen amount obtained by theoretical calculation was almost same with the result solved by finite element analysis. The distribution of hydrogen concentration and average concentration was calculated for a flat specimen. Also, finite element analysis was employed to simulate the redistribution of hydrogen due to stress gradient. The calculation of hydrogen concentration diffused into the material by finite element method will provide the basis for the prediction of delayed fracture of notched specimen. The distribution of hydrogen concentration invaded into the smooth and notched specimen was obtained by finite element analysis. The hydrogen amount is much in smooth specimen and tends to concentrate in the vicinity of surface. Hydrogen embrittlement susceptibility of notched specimen after hydrogen charging is more remarkable than that of smooth specimen.

Benzo(a)pyrene 과 Cytochrome P-450의 대한 상호작용에 대한 이론적 연구 (Theoretical Study on The Interaction Between Benzo(a)pyrene and Cytochrome P-450)

  • 도성탁
    • 대한의생명과학회지
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    • 제1권1호
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    • pp.89-94
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    • 1995
  • B(a)P와 cytochrome P-450의 heme부분은 구조가 평면이므로 겹침 상호작용이 가능하다. 가능성이 큰 겹침 상호작용모형을 결정하기 위해 이들 분자에 대해 MO계산을 행하였다. 이 경우 궤도함수 상호작용이 가장 중요하므로, 프론티어궤도함수의 eigen vetor값이 크며 상호 결합성을 보여야 한다. 이를 바탕으로 다섯가지 가능성이 있는 모형을 선택한 수 MN2와 MO방법을 실행하였다. 이중 B(a)P의 4, 5, 6번 위치와 heme group의 Y탄소와 III pyrrole환이 포개어지는 형태가 가장 안전하였다.

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박막전지용 Si/Mo 다층박막 음극의 전기화학적 특성 (Characterization of Si/Mo Multilayer Anode for Microbattery)

  • 이기령;정주영;문희수;이승원;이유기;박종완
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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    • pp.209-209
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    • 2003
  • The adventages of Li alloys have attracted the attention of many research groups, many of which have investigated tin-based alloys [1-2], Despite interesting performances of these, the irreversible capacity loss systematically observed on the first cycle for these compounds is a main drawback for their use as anode materials in lithium ion cells. Not only Sn is efficient in forming alloys with Li, Si can also react with Li to form alloys with a high Li/Si ratio, like Li$\_$22/Si$\_$5/ at 400$^{\circ}C$. It corresponds to a capacity of 4200mAh/g. Electrochemical Li-Si reaction occurs between 0 and 0.3 V against Li/Li$\^$+/, so that high-energy density battery can be realized. Despite the high theoretical capacity of elements like Si, however, particles of the alloys crack and fragment due to the repeated alloying and do-alloying which occurs as cell are charged and discharged. The research groups of Muggins [3] and Besenhard [4] have proposed that the volume expansion due to the insertion of Li can be reduced in micro- and submicro-structured matrix alloys. For this reason, the research group of J.R. Dahn investigated Sn/Mo sequential sputter deposition to prepare nanocomposites [5]. In this study, we investigated the characterization and the electrochemical characteristics of sequentially sputtered Si/Mo multilayer for microbattery anode.

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MO 理論에 依한 反應性의 決定 (第16報). 카르보닐炭素의 酸觸媒置換反應에 關한 理論的 硏究 (Determination of Reactivities by MO Theory (ⅩⅥ). Theoretical Studies on Acid Catalyzed Displacement Reactions at Carbonyl Carbon)

  • 이익춘;이순기;이계수
    • 대한화학회지
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    • 제24권3호
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    • pp.201-208
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    • 1980
  • CNDO/2 MO 계산방법을 사용하여 양성자화된 아세트알데히드와 알코올 및 양성자화된 아세트산과 알코올간의 기체반응에 대한 전이상태구조를 최적화하였다. 계산으로 얻은 구조에 따르면 전자의 반응은 공격하는 알코올의 alkyl-O 절단으로 진행되고 후자의 반응은 acyl-O 절단으로 진행될 것임을 보여주어 실험결과와 일치하였다. 또 반응물질들의 eigenvector 성질들로 판단할 때 전자의 반응은 charge controlled인 반면 후자의 반응은 orbital controlled임을 예측케 해주었다. Caserio 등이 제안한 전이상태를 가정한 CNDO/2 활성화에너지 결과에 따르면 후자의 경우는 실험결과와 일치하는 알코올의 반응성 순위를 주지만 전자의 경우는 실험결과와 반대되는 순위를 주었다.

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소결 공정 개선을 통한 미세 결정립 몰리브덴 소결체 제조 (Fabrication of Fine-grained Molybdenum Sintered Body via Modified Sintering Process)

  • 이태호;김세훈;박민서;석명진;김영도
    • 대한금속재료학회지
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    • 제49권11호
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    • pp.868-873
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    • 2011
  • In this study, the fabrication of ultra fine grained Mo bulk was conducted. $MoO_3$ nanopowders were prepared by a high energy ball-milling process and then reduced at the temperature of $800^{\circ}C$ without holding time in $H_2$ atmosphere. The particle size of Mo nanopowder was ~150 nm and grain size was ~40 nm. The two-step process was employed for the sintering of Mo nanopowder to obtain fine grain size. The densification over 90% could be obtained by the two-step sintering with a grain size of less than 660 nm. For higher density, modified two-step sintering was designed. 95% of theoretical density with the grain size of 730 nm was obtained by the modified two-step sintering.