• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.462-462
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• 2014

The effect of rear passivation for passivated emitter and rear cell (PERC) using ozone and H2O oxidant of atomic layer deposited (ALD) Al2O3 was studied by post-annealing in N2 and forming gas ambients. Rear surface of PERC solar cell was passivated by Al2O3 grown by ALD with ozone and H2O oxidant. Al2O3 grown by ALD with ozone oxidant has been known to have many advantages, such as lower interface defects, low leakage current density. Its passivation quality is better than Al2O3 with H2O. Al2O3 layer with 10 nm and 20 nm thickness was grown at $150^{\circ}C$ with ozone oxidant and at $250^{\circ}C$ with H2O oxidant. And then each samples were post-annealled at $450^{\circ}C$ in N2 ambients and at $850^{\circ}C$ in forming gas ambients. The passivation quality was investigated by measuring the minority carrier lifetime respectively. We examined atomic layer deposited Al2O3 such as growth rate, film density, thickness, negative fixed charge density at AlOx/Si interface, and reflectance. The influences of process temperature and heat treatment were investigated using Sinton (WCT-120) by Quasi-Steady State Photoconductance (QSSPC) mode. Ozone-based ALD Al2O3 film shows the best carrier lifetime at lower deposition temperature than H2O-based ALD.

• 한국재료학회지
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• 제26권1호
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• pp.47-53
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• 2016

Silicon nitride ($SiN_x:H$) films made by plasma enhanced chemical vapor deposition (PECVD) are generally used as antireflection layers and passivation layers on solar cells. In this study, we investigated the properties of silicon nitride ($SiN_x:H$) films made by PECVD. The passivation properties of $SiN_x:H$ are focused on by making the antireflection properties identical. To make equivalent optical properties of silicon nitride films, the refractive index and thickness of the films are fixed at 2.0 and 90 nm, respectively. This limit makes it easier to evaluate silicon nitride film as a passivation layer in realistic application situations. Next, the effects of the mixture ratio of the process gases with silane ($SiH_4$) and ammonia ($NH_3$) on the passivation qualities of silicon nitride film are evaluated. The absorption coefficient of each film was evaluated by spectrometric ellipsometry, the minority carrier lifetimes were evaluated by quasi-steady-state photo-conductance (QSSPC) measurement. The optical properties were obtained using a UV-visible spectrophotometer. The interface properties were determined by capacitance-voltage (C-V) measurement and the film components were identified by Fourier transform infrared spectroscopy (FT-IR) and Rutherford backscattering spectroscopy detection (RBS) - elastic recoil detection (ERD). In hydrogen passivation, gas ratios of 1:1 and 1:3 show the best surface passivation property among the samples.

• 한국통신학회논문지
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• 제17권1호
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• pp.58-67
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• 1992

MgGa2Se4 및 MgGa2Se4 : Co2+단결정을 bridgman 방법으로 성장하여 광흡수와 광발광을 가시광 영역과 근적외선 영역에서 조사하였다. 광흡수 스펙트럼은 MgGa2Se4단결정의 Td Symmetry를 갖는 host lattice에 점유하여 바닥상태와 여기상태의 Co2+ ion 에너지 ㅣlevel간 전자전이에 의해서 760nm, 1640nm, 그리고 2500nm에서 3개의 흡수피크를 관측하였다. 광발광 스펙트럼에서 이 단결정은 가시광 발광ㄸ들을 관찰하였다.가시영역의 발광 band들은 에너지 준위도에서 제안된 바와 같이 자전자대의 우의 꼭대기 acceptor 준위에서 전도대 아래의 밑에 분포된 trap으로부터 끊임없이 전자전에 의한다고 볼수 있다. 한편, 이들은 적외선 발광 band가 deep level에서 acceptor level부터 전자전이에 기인한다고 고려할 수 있다. 광전이의 mechanism은 MgGa2Se4 결정의 에너지 diagram의 항으로 잘 설명되고 있다.

• 한국통신학회논문지
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• 제29권9A호
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• pp.1022-1030
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• 2004

차세대 이동 및 우선통신 시스댐은 현재보나 얘우 큰 고속의 데이터 전송과 시스템 용량을 요구하고 였으며 이러한 요구를 충족시키기 위해서 복수의 안테나를 사용하여 송수신을 하는 MIMO(m 비 tiple input, multiple output) 기술이 널리 연구되고 있다 이 논문은 다수의 안테나를 가지고 있는 기지국, 소수의 안테나를 가지고 있는 단말기의 하향 링크에서 스케터령과 변동이 적으며 평탄한 페이딩 채널을 가정한다. 단영 사용가 MIMO 시스템에서 가지국이 채널상태정보를 가지고 있다연 SVD(singular value decomposition) 와 water filling 읍 사용 한 MIMO 기숭이 최대의 채널용량을 이룬다. 그러나 복수 사용자 시스템의 경우에는 공간분할 다중접속 기술을 이용하여, 보다 큰 전체 채널용량을 얻는 것이 가능하다 이 논문은 복수 사용가 시스템에서 각 사용자에게 복수 의 데이터 스트림을 전송하는 MIMO 공간분할 다중접속 기술을 제안한다. 제안하는 기술은 SVD 기반의 MIMO 기술이나 스마트 안테나를 사용한 공간분항 다중정속 기술보다 더 큰 전체 채널용량을 얻을 수 있다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.135-136
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• 2012

Carbon atoms near the surface of W(110) induce reconstructions such as $R(15{\times}12)$ -C/W(110) which consists of two characteristic parts, one square shaped and bright protrusion and two smaller ones. In the atomic resolution STM image, the bigger protrusion shows the periodicities of clean W(110), indicating that it is almost carbon poor region. The smaller protrusion contains hexagonal carbide surface layer of ${\alpha}$-W2C on W(110). Employing this carburized W(110) as templates, we grow Co and Fe clusters of less than ten atoms. Due to the selectivity of bonding sites, growth of larger cluster is highly unfavorable for Co and the size of clusters is very uniform. Since Co atoms prefer to sit on the bigger protrusion rather than smaller one, Co cluster can be arranged one-dimensionally in $R(15{\times}12)$-C/W(110) with quite uniform size distribution. However, Fe clusters sit on both sites without favored site, but still with uniform size distribution. On the other hand, Fe clusters can be grown with quasi one-dimensional order in $R(15{\times}3)$-C/W(110), which consists of only smaller protrusions. We investigate the magnetic properties of the ordered nano-sized clusters. Experiments using XMCD reveals little magnetic moment of Co cluster on $R(15{\times}12)$-C/W(110). This observation is consistent with the predictions of our first principles calculations that small Co clusters can be nonmagnetic or antiferromagnetic with low mean magnetic moment per atom.

• Child Health Nursing Research
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• 제17권2호
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• pp.100-110
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• 2011

Purpose: The purpose of this study was to analyze papers published in the Journal of Korean Academy of Child Health Nursing (JKACHN) to identify the current state of child health nursing research and recommend directions for future research. Methods: Using analysis criteria developed by the researchers, 233 papers published in JKACHN between 2005 and 2009 were reviewed. Results: Both quantity and quality of these papers showed significant improvement compared to before 2005. The number of published papers, the proportion of intervention studies, and studies that involved children directly as participants had increased. However, published papers still leave much to be desired. Quantitative studies were dominant (91.4%) and many of these studies were survey designs (65.7%). Children, especially young children were still less likely to be direct participants. All experimental studies were quasi or pre-experimental studies. There were few qualitative research studies. Conclusion: Findings of this study indicate that strengthening peer review according to review guidelines will improve the quality of published papers and promote JKACHN as an international journal. Instead of proxy accounts from parents or nurses, research involving direct accounts by children is needed. Child-friendly data collection methods need to be developed and used by child health nurse researchers.

• Journal of Korean Biological Nursing Science
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• 제22권1호
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• pp.1-10
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• 2020

Purpose: Diabetes Mellitus (DM) is a leading cause of death with a prevalence rate of 12.4% in South Korea. Self-management is crucial for patients with DM, because many studies have reported that self-management intervention based on the Health Belief Model (HBM) is effective. The purpose of this study was to investigate the current state of HBM based intervention studies and the components and effects of the theories used in the study for diabetes patients. Methods: A systematic review was conducted using the Pubmed, Cochrane Library and Embase databases from January 2009 to May 2019. We reviewed characteristics of intervention based on the HBM in randomized controlled clinical trials (RCTs), quasi-experimental study intervention. Results: Eight studies published in English between 2009 and 2019 were included in this review. The key components of the health behavior promotion program applied to the DM patients were perceived susceptibility, perceived severity, perceived benefits, perceived barriers and self-efficacy. The intervention based on these components has reported to significantly increase the health behavior change, likelihood of taking health action and improve physiological indicators (HbA1c, and fasting blood sugar etc.). Conclusion: This study highlighted the importance of intervention programs based on the HBM for DM patients.

• Child Health Nursing Research
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• 제8권3호
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• pp.322-333
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• 2002

Purpose: The purpose of study was : 1) to analyse the trend of research on the sensory stimulation in newborn in Korea, 2) to suggest direction for further study on the sensory stimulation in newborn and contributing to the use of intervention in newborn. Method: Research studies on the sensory stimulation in newborn were selected from the dissertations, parents-child health. Academic Society Journal, and from Korean Journal of Pediatrcs which were conducted between 1984 and 2002. The total numbers of the studies were 15. These studies were analyzed for 1) time of publication or presentation 2) thesis for a degree or nondegree 3) characteristics of subjects 4) sample size 5) research design 6) type of sensory stimualtion 7) meaurement tool 8) result. Result : 1)The most year of studies were the 1996's～ 2000's. 2) The degree of studies were higher than nondegree. 3) The most characteristics of subjects were the premature infants. 4) The most frequent sample sizes were 11-20. 5) The all research design was nonequivalent control group pretest-posttest design in quasi experimental basis. 6) The most type of sensory stimulation was Field massage(tactile and kinesthetic). 7) The measurement tool used all objective tools. 8) The most research data were collected by the measure of the weight, heart rate, behavior state, respiration, stress hormon and positive results. Conclusion: 1) Human sensory stimulation did not seem to harm the infants. 2) several positive effects of sensory stimulation that have been reported previously must be reevaluated. 3) further research will be required large sample size, long-term outcome, individualized stimulation program, early parent-infant contact in order to enhance the development of attachment, to determine the underlying mechanism and theorical frame for these stimulation effect.

• 동서간호학연구지
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• 제8권1호
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• pp.63-72
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• 2003

Purpose: The Purpose of this study was to test the effects of the Muscles Along Meridians Release Therapy on the function of upper limb as a means of nursing intervention. Method: The design used for this study was quasi - experimental with a nonequivalent control group pretest - post test design. The subjects were 40 stroke patients who were admitted in K oriental medical center of K University. This study was carried out from 6, May to 18, October, 2003. The experimental group (21) and the control group (19) were assigned by means of Participation order. The experimental group took Muscles Along Meridians Release Therapy on affected upper limb for 3 minutes daily for 2 weeks. Outcome were assessed by Modified Ashworth Scale, VAS, Fugl - Meyer score and goniometer. Data were analysed by SPSS PC. Result: After 2 weeks of treatment, function of affected upper limb, elbow joint spasticity were significantly better than control group, but, there was no significant difference in pain between experimental group and control group. Conclusion: The above results state that the Muscles Along Meridians Released Therapy could be an effective intervention for improving upper limb function and elbow joint spasticity of stroke patients.

• 대한조선학회논문집
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• 제29권3호
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• pp.131-139
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• 1992

본 연구에서는 Dommermuth and Yue(1987)의 고차 스펙트럴법에 새로이 물체 포텐셜을 도입하여 물체와 자유표면과의 비선형 상호작용 문제를 다룰 수 있는 새로운 수치해법을 개발하였다. 또한, 이를 이용한 2차원 수치 파수조(numerical wave tank)에서 잠수 주상체의 조파저항문제와 규칙파군을 얻기 위한 조파 및 소파문제를 적용예로 다루었다. 계산예들을 통하여 초기의 물체운동이 급격히 시작되면 상당한 과도파를 유발하여 유용한 결과를 얻는데 실제적인 장애가 됨을 보였고, 초기의 점진적인 구동에 의해 이를 억제할 수 있음을 보였다. 본 수치해법은 자유표면의 분할요소수를 N이라 할때 계산량이 NlogN에 비례하여 증가하는 매우 효율적인 수치해법이며, 앞으로 그 활용이 기대 된다.