• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.163-163
• /
• 2011

셀레늄(Selenium: Se) cracker cell을 이용하여 셀렌화한 $CuInSe_2$ (CIS)박막에 대해 연구한 결과를 발표하고자 한다. 화석연료의 과도한 사용으로 지구온난화라는 환경문제가 대두되면서 영구적이고 무상의 태양에너지 이용에 대한 필요성이 점차 높아지고 있다. 빛에너지를 전기에너지로 변화시키기 위한 태양전지는 재료에 따라 다양하게 개발되고 있으며 그 중 가장 주목을 받고 있는 것 중의 하나가 $CuInSe_2$을 광흡수층으로 하는 CIS 박막 태양전지이다. CIS 박막은 태양전지의 광흡수층으로 사용되는데 직접천이형 밴드구조를 가지고 있고, 약 $10^5$ $cm^{-1}$의 높은 광흡수계수를 가지고 있어 태양전지 광흡수층으로 적합한 물질로 각광받고 있다. CIS는 에너지 밴드갭이 ~1 eV로 실리콘과 유사한 밴드갭을 가지고 있으나 이는 Ga, Al을 In 대신 치환함으로 조절할 할 수 있다. 무엇보다도 sodalime 유리와 같은 저가의 기판위에 스퍼터와 같은 장치로 대면적 CIS 박막태양전지를 만들 수 있다는 것이 산업적인 면에서 장점으로 알려져 있다. 본 연구에서는 sodalime 유리기판 위에 스퍼터 방법으로 CIS 박막을 증착하고 Se cracker cell로 셀렌화하여 CIS 박막을 제조하는 것을 조사연구 하였다. 스퍼터를 이용하여 유리기판위에 Mo (Molybdenum)을 증착하고 그 위에 Cu-In-Se박막을 증착하였다. Cu-In-Se/Mo/유리기판 시료는 동일 챔버에서 Se cracker cell을 이용하여 셀렌화 처리 하였다. 물성비교를 위하여 Knudson-cell을 이용한 셀렌화도 시행하였다. Se cracker cell은 고체 Se를 가열하는 부분(R-zone)과 Se flux를 cracking 하는 부분(C-zone)으로 나누어져 있으며 C-zone은 700$^{\circ}C$로 고정하였다. 셀렌화 기판 온도는 425$^{\circ}C$로 고정하였고 Se cracker 온도는 330~375$^{\circ}C$까지 변화시켜 가며 CIS 박막을 제조하였다. 제조된 CIS 박막의 물성 조사는 사진, 현미경, SEM, EDX, XRD, Hall effects를 이용하였다. Se cracker cell로 셀렌화한 CIS 박막은 island 구조를 하고 있음을 알 수 있었다. CIS 박막의 island의 크기와 모양은 셀렌화시 R-zone 온도(Cu-In-Se 박막에 조사되는 셀레늄의 량)에 큰 영향을 받았다. 셀렌화시 셀레늄량이 적을 때는 island가 커지며 불균일해지고 셀레늄량이 많을 때 island가 작고 균일해지는 경향을 SEM을 통해 관찰할 수 있었다. X-ray 회절을 통해 셀레늄량이 적을 경우 CIS 결정이외의 결정이 박막내에 형성됨을 알 수 있었다. 학술회의에서 Se cracker cell을 이용한 셀렌화에 관한 보다 깊은 연구결과를 발표하고자 한다.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.119-120
• /
• 2011

Kawazoe는 1997년 p-type TOS를 만들기 위해서는 3가지가 충족되어야 한다고 언급한바 있다. 첫 번째, 가시광영역에서 투명하기 위해서 cation의 d10s0이 가득 차야 한다. 가득 차지 않은 d10 shell은 광 흡수가 가능하여 투과도를 떨어뜨린다. N-type을 예로 들어 ZnO, TiO, In2O3가 각각 Zn2+, Ti4+, In3+가 되어 d shell을 가득 차게 만드는 것을 볼 수 있다. 두 번째, cation d10s0 shell은 산소의 2p shell과 overlap 되어야 한다. 이 valence band는 홀 전도를 더욱 좋게 한다. 예를 들어 Cu1+(3d), Ag1+(4d)가 해당한다. 세 번째로, 양이온과 산소간의 공유결합을 강하게 하기 위해서 결정학적 구조는 매우 중요하다. Delafossite 구조는 산소가 pseudo-tetrahedral 구조로서 공유결합에 유리하다. 이러한 환경은 O2- (2p6)을 형성하고 홀의 이동도를 증가시킨다. 예를 들어 Cu2O의 경우 앞의 2가지를 만족시키지만 광학적 특성에서 좋지 않다. 그 이유가 3번째 언급한 결정학적인 요인에 있다. 결정 계의 환경은 Cu2O를 따라가면서 3차원적인 연결을 2차원적으로 변형된 delafossite 구조에서는 quantum well이 형성되어 band gap이 커진다. 본 연구에서는 전기적 이방성을 가지고 있는 delafossite CuCrO2 상에서 우선배향을 일으키는 인자 중 기판을 변화시켜 실험을 진행하였다. 결과적으로 기판변화를 통해 우선배향조절이 가능하였으며 CuCrO2 박막을 시켰으며, 결정방향에 따른 전기적 물성의 이방성에 관한 연구는 계속 진행 중에 있다. c-plane sapphire 기판위에는 [00l]로 성장하는 반면, c-plane STO 기판 위에는 [015] 방향으로 성장하는 것을 확인하였다. 이러한 원인은 기판과 증착되는 박막간의 mismatch를 최소화 하여 strain을 줄이고, 계면에서의 Broken boning 수를 줄여 계면에너지를 낮추는 방법이기 때문일 것으로 예상된다. C-plane sapphire 기판위에 증착될 경우 증착온도가 증가함에 따라 c-축으로의 성장이 온전해지며 이에 따라 캐리어농도의 감소와 모빌리티의 증가가 급격하게 변하는 것을 확인할 수 있다. 반면 c-plane STO 기판에서는 증착온도에 따른 박막의 배향변화가 없으며 전기적 물성 변화 또한 비교적 작은 것을 간접적으로 확인하였다.

• Journal of Hospice and Palliative Care
• /
• v.7 no.2
• /
• pp.179-188
• /
• 2004

Purpose: The purpose of this study was to investigate the degree of fatigue and its related factors in cancer patients during chemotherapy. Methods: The subjects of this study consisted of 90 patients over 20 years old who were receiving chemotherapy at the injection room of the o.p.d. and ward admission care unit in a University hospital located in Gwang-ju city and data were collected from August 8th to October 2nd, 2002. Collected data were analysed using SPSS v 10.0. to obtain summary statistics for the descriptive analysis, t-test, ANOVA, pearson correlation, and multiple regression. Results: 1. Fatigue of the subjects was significantly correlated with physical distress score. and 6 items of subscale those were nausea, vomiting, anorexia, pain, and immobility, showed statistically significant correlation. 2. Fatigue of the subjects showed statistically significant differences according to a nap satisfaction. Fatigue of the subjects was significantly correlated with mood state, Also, all 5 items of subscale, which are those were anxiety, confusion, depression, energy, and anger showed statistically significant correlations. 3. Fatigue of the subjects showed statistically significant differences according to metastasis, chemotherapy cycle, post operation existence, post radiation therapy existence. There were significant negative correlation between fatigue and hematocrit and fatigue and weight change. There was no significant correlation between fatigue and spiritual well-being state. With the result to multiple regression, Immobility, Anorexia, Anger explained fatigue by, pain, and immobility showed statistically significant correlation.

• Tuberculosis and Respiratory Diseases
• /
• v.72 no.5
• /
• pp.452-456
• /
• 2012

Disseminated Mycobacterium avium complex (MAC) infection can occur in immunocompromised patients, and rarely in immunocompetent subjects. Due to the extensive distribution of the disease, clinical presentation of disseminated MAC may mimic malignancies, and thorough examinations are required in order to make accurate diagnosis. We report a case of disseminated Mycobacterium intracellulare disease in an immunocompetent patient, which involved the lung, lymph nodes, spleen, and multiple bones. F-18 fluorodeoxyglucose positron-emission tomography imaging showed multiple hypermetabolic lesions, which are suggestive of typical hematogenous metastasis. However, there was no evidence of malignancy in serial biopsies, and M. intracellulare was repeatedly cultured from respiratory specimens and bones. Herein, we should know that disseminated infection can occur in the immunocompetent subjects, and it can mimic malignancies.

• Korean Journal of Environment and Ecology
• /
• v.25 no.3
• /
• pp.421-431
• /
• 2011

This study examined visitors' perceptions and attitudes about establishing cable car in Mudeungsan Provincial Park (MPP). Data were collected from 401 respondents by a field questionnaire survey in MPP during the September of 2010. 61.7% of respondents opposed to establishing cable car in MPP while 20.6 percent supported it. Respondents showed high level of belief to possible consequences that establishing cable car will result in 'deterioration of ecosystem and natural landscape', 'crowding problem by increased number of visitors', 'disappearance of naturalness or previous nature experiences in MPP'. Respondents, however, presented low belief to 'positive effects on increasing economic income and local economic growth by attracting tourists'. 32.4 percent of the survey respondents evaluated the present MPP as a place of 'Nature Preservation Area (NPA)' and 10.5% as 'Developed Park Area (DPA)'. 48.8% of respondents answered that MPP should be managed as 'NPA' with only 2.5% as DPA. Respondents' socio-demographic characteristics (i.e., gender, age, education level, length of residence in Gwang-ju city), use patterns (number of visits to MPP or to Jungbong and surrounding areas), and normative place condition of MPP showed relationship with the overall support rates about establishing cable car. The results and their implications were discussed.

• The Journal of the Korea Contents Association
• /
• v.10 no.12
• /
• pp.59-69
• /
• 2010

The research on protein for the diseases analysis and the new medicines development is one of the most important themes in biotechnology. Since the analysis on diseases and protein needs to handle a large scale of data, we don't use the way to approach it by the experiments anymore. In recent, we have accelerated the research on diseases and protein analysis by sharing and connecting the various experimental data by combining the biotechnology with the IT technology. However, many biotechnology researchers have difficulty in handling the protein analysis tools based on the IT knowledge. In order to solve such problems, data analysis tools through the cooperation between IT researchers and biologists have been developed. However, the existing data analysis tools still have the problems that it is very hard for biologists to extend their functions and to use them. In this paper, we design and implement an effective analysis system for diseases and protein based on components that alleviates the problems of the existing data analysis systems.

• Journal of Conservation Science
• /
• v.26 no.4
• /
• pp.377-383
• /
• 2010

The effect of gamma irradiation on the microbial growth inoculated in the Korean traditional paper, Hanji, was investigated. Also, the mechanical properties of Korean traditional paper were measured to verify the possible change by gamma radiation. Bacillus cereus and Aspergillus niger were cultivated and the spores were innoculated in papers at the 250,000 and 500,000 colonies, respectively. In these results, 5log spores of B. cereus could be all inactivated at the dose of 6 kGy, and 5log A. niger be inactivated at 8 kGy, respectively. There was also showed no significant change in tensile strength, bursting strength and color index of Korean traditional paper by the gamma irradiation upto the dose of 50 kGy. These results confirmed that radiation treatment of Korean traditional paper is extremely efficient and could be used to preserve ancient books and archives documents from being damaged by moulds and fungi.

• Journal of the Korea Convergence Society
• /
• v.9 no.2
• /
• pp.267-276
• /
• 2018

The purpose of this study was to verify the effectiveness of horticultural activities program for 4th grade nursing students' emotional intelligence and stress coping. The study method was a non-equivalent control group pretest-posttest design. Participants were recruited with 4th grade nursing students from two nursing colleges. They were assigned to the experimental group (n=29) or the control group (n=30) using a computerized blocked randomization. Horticultural activities program was consisted of 10 sessions which were 2 times a week for 80 mins at each session during 5 weeks. Pretest and posttest were used to measure emotional intelligence and stress coping using the same structured questionnaires. Data was analyzed using frequency analysis, descriptive statistics, ${\chi}^2-test$, t-test, Fisher's exact test, Kolmogorov-Smirnov, independent t-test and paired t-test. The result showed a significant difference that the experimental group's emotional intelligence(t=-3.33, p=.002) and stress coping(t=-2.35, p=.023) score was higher than the control group's. The results of this study suggests that the horticultural activities program is effective in terms of emotional intelligence and stress coping for $4^{th}$ grade nursing students.

• Journal of Gastric Cancer
• /
• v.17 no.2
• /
• pp.120-131
• /
• 2017

Purpose: Tumor bleeding is a major complication in inoperable gastric cancer. The study aim was to investigate the effects of proton pump inhibitor (PPI) treatment for the prevention of gastric tumor bleeding. Materials and Methods: This study was a prospective double-blind, randomized, placebo-controlled trial. Patients with inoperable gastric cancer were randomly assigned to receive oral lansoprazole (30 mg) or placebo daily. The primary endpoint was the occurrence of tumor bleeding, and the secondary endpoints were transfusion requirement and overall survival (OS). Results: This study initially planned to enroll 394 patients, but prematurely ended due to low recruitment rate. Overall, 127 patients were included in the analyses: 64 in the lansoprazole group and 63 in the placebo group. During the median follow-up of 6.4 months, tumor bleeding rates were 7.8% and 9.5%, in the lansoprazole and placebo groups, respectively, with the cumulative bleeding incidence not statistically different between the groups (P=0.515, Gray's test). However, during the initial 4 months, 4 placebo-treated patients developed tumor bleeding, whereas there were no bleeding events in the lansoprazole-treated patients (P=0.041, Gray's test). There was no difference in the proportion of patients who required transfusion between the groups. The OS between the lansoprazole (11.7 months) and the placebo (11.0 months) groups was not statistically different (P=0.610). Study drug-related serious adverse event or bleeding-related death did not occur. Conclusions: Treating patients with inoperable gastric cancer with lansoprazole did not significantly reduce the incidence of tumor bleeding. However, further studies are needed to evaluate whether lansoprazole can prevent tumor bleeding during earlier phases of chemotherapy (ClinicalTrial.gov, identifier No. NCT02150447).

• Tuberculosis and Respiratory Diseases
• /
• v.63 no.5
• /
• pp.444-448
• /
• 2007

Recently, intra-Muscular Stimulation (IMS) therapy is being increasingly used for musculoskeletal pain. This procedure is generally regarded as a safe procedure for the general public. Some cases of iatrogenic pneumothorax caused by acupuncture have been reported in the medical literature. However, a case of an IMS therapy associated pneumothorax has not reported. We experienced two cases of iatrogenic pneumothorax after IMS therapy. A 62 year-old man received IMS therapy on the right shoulder due to posterior neck pain. After IMS therapy, acute dyspnea and chest discomfort developed. The other patient was a 74 year-old woman who also received IMS therapy. This patient experienced a nonproductive cough and acute dyspnea after the treatment. As the popularity of this form of alternative medicine increases, we might expect to see more cases of iatrogenic pneumothorax. Physicians should be aware of the adverse events associated with IMS therapy.