Chalcogenization-Derived Band Gap Grading in Solution-Processed CuIn_<i>x</i>Ga_1–<i>x</i>(Se,S)₂ Thin-Film Solar Cells

Park, Se Jin,Jeon, Hyo Sang,Cho, Jin Woo,Hwang, Yun Jeong,Park, Kyung Su,Shim, Hyeong Seop,Song, Jae Kyu,Cho, Yunae,Kim, Dong-Wook,Kim, Jihyun,Min, Byoung Koun American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.49

<P>Significant enhancement of solution-processed CuInxGa1-x(Se,S)(2) (CIGSSe) thin-film solar cell performance was achieved by inducing a band gap gradient in the film thickness, which was triggered by the chalcogenization process. Specifically, after the preparation of an amorphous mixed oxide film of Cu, In, and Ga by a simple paste coating method chalcogenization under Se vapor, along with the flow of dilute H2S gas, resulted in the formation of CIGSSe films with graded composition distribution: S-rich top, In- and Se-rich middle, and Ga- and S-rich bottom. This uneven compositional distribution was confirmed to lead to a band gap gradient in the film, which may also be responsible for enhancement in the open circuit voltage and reduction in photocurrent loss, thus increasing the overall efficiency. The highest power conversion efficiency of 11.7% was achieved with J(sc) of 28.3 mA/cm(2), V-oc of 601 mV, and FF of 68.6%.</P>

A Comparative Study of Nanoparticle-Ink-Based CIGSSe Thin Film Solar Cells on Different Back Contact Substrates

Se Jin Park,Jin Woo Cho,Gi Soon Park,Jae Seung Jeong,김지현,고두현,황윤정,민병권 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.3

The effect of the back contact electrode in nanoparticle-ink-based CIGSSe solar cells was investigated using different glass substrates with either a fluorine-doped SnO2 (FTO) conducting layer or a molybdenum (Mo) conducting layer. The morphologies, crystal structures, and compositional distributions of the Cu(In x Ga1– x )(S y Se1– y )2(CIGSSe) films are very similar in spite of the different back contact materials. The observed performances of the solar cell device, however, are somewhat different. The device that was fabricated on the FTO back contact substrate revealed a lower open-circuit voltage ( V oc) and fill factor (FF) than the Mo back contact substrate, resulting in lower solar cell efficiencies (6.5% for FTO and 7.4% for Mo). The differences between the behaviors are attributed to the interfacial properties between the CIGSSe film and the back contact electrode.

체간안정화 훈련이 만성 뇌졸중 환자의 호흡기능에 미치는 효과

이경진(Kyeong-Jin Lee),정주현(Ju-Hyeoun Jeong),조명래(Myeong-Rae Jo),김세윤(Se-Yoon Kim),김난수(Nan-Soo Kim) 대한심장호흡물리치료학회 2019 대한심장호흡물리치료학회지 Vol.7 No.1

Purpose : The purpose of this study is to examine the effects of trunk stability training on improving trunk control, respiratory function, and respiratory muscle activation in stroke patients. Methods : The subjects were assigned to two groups: the intervention group (n=15) and the control group (n=15). Both groups participated in a conventional stroke rehabilitation program, but the intervention group also received trunk stability training for 30 minutes a day, 3 times a week, for 6 weeks. The main trunk stability exercise consisted of the dead bug exercise. Trunk control was assessed using a trunk impairment scale, and respiratory function (pulmonary function and respiratory muscle function) was assessed using spirometry. The data were analyzed using the Pearson correlation, independent t-test, and paired t-test. Results : Trunk control was significantly positively correlated with pulmonary function and respiratory muscle strength. Both groups showed a significant increase in trunk control and respiratory function. Conclusion : This study demonstrated that a conventional stroke rehabilitation program and trunk stability training have positive effects on respiratory function and respiratory muscle activation in stroke patients.

포화수증기압 개념에 대한 예비 과학 교사들의 이해

정진우,박세진,김윤지 韓國敎員大學校 敎育硏究院 2009 敎員敎育 Vol.25 No.4

본 연구는 예비과학교사들이 포화수증기압 개념을 설명하는 과정에서 나타나는 이해를 밝히고자 하였다. 과학교육을 전공하는 여섯 명의 예비과학교사들을 대상으로 포화수증기압에 대한 설명을 요구하는 반구조화된 면담이 이루어졌다. 전사된 면담 내용과 비디오자료, 그리고 설명 과정에서 그려진 스케치 자료를 분석하여 참여자의 이해를 구조화하였다. 연구 결과, 예비과학교사가 대기 중의 물 개념을 설명하는 과정에서 다양한 이해가 표출되었다. 포화수증기압에 대한 이해로 분자운동론적 설명, 대기의 영향을 고려한 분자운동론적 설명, 기화압력을 이용한 설명, 확산 개념을 이용한 설명, 수증기의 공간을 한정시키는 설명이 나타났다. 예비과학교사들은 포화수증기압 개념에 대해 다양한 대안 개념을 가지고 있으며, 물의 상태 변화에 대한 분자운동론적 이해와 포화수증기압 개념을 통한 이해가 서로 연결되지 못하고 있음을 보여주었다. The purpose of this study is to analyze the understandings that represent that, in this course, the preservice science teachers have explained the concept of saturation vapor pressure. To do so, semi-structured interviews that requested students to explain saturation vapor pressure to six preservice science teachers were carried out. The preservice science teachers' understanding of the material was constructed by analyzing transcribed protocols, video tapes, and sketches that were drawn during the explanation. As a result of the research, a variety of understandings was discovered when the preservice science teachers explained the concept of atmospheric water. Understandings about saturation vapor pressure include the idea of molecular motion; the molecular motion model is considered to influence atmospheric pressure, the evaporation pressure model, the diffusion model and the limited space model. Preservice science teachers had alternative conceptions of saturation vapor pressure. The understanding of saturation vapor pressure and the understanding of the molecular motion model describing the change of water state are not connected.

Mathcad를 사용한 혼합계면활성제의 상호작용 파라미터의 계산

김수진,고정수,오세웅 木浦大學校 基礎科學硏究所 2001 基礎科學硏究誌 Vol.19 No.-

Home-built program was developed for the calculation of the interaction parameters for the mixed surfactant systems using a commercial software, Mathcad. The program was applied to the mixed surfactant systems which were published already, and gave the same values as the previous results. The program might be able to show the best averaged interaction parameters for the mixtures of surfactants through the process iteratively.

FEM을 이용한 선삭가공 절삭조건의 영향 분석

임세환,송춘삼,홍석관,강정진,김주현 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

A plane strain finite element model is developed to simulate turning with continuous chip formation using adaptive remeshing during the thermal-mechanical coupled analysis. Comparisons between the experimental and simulation results for cutting forces are performed to validate FE analysis results. Influences of machining parameters such as depth of cut, cutting speed and feed rate on cuting force and shear angle are analyzed by Taguchi method. The more depth of cut and feed rate result in the increase of cutting forces, but the rates of increase are decrease due to the larger shear angle. As the cutting speed increases, von Mises stress of workpiece near the tool tip decreases because the strength of specimen decreases at high temperature above 500℃. This thermal effect on cutting force is negligible because the affected area is very localized and the average values of von Mises stress in the shear plane are the same among the diverse cutting parameters.

정맥주입 전문간호사가 삽입한 말초삽입형 중심정맥관(PICC) 사용 결과에 대한 후향적 분석

박정윤,박광옥,백미경,김세라,권혜리,양수진 대한기초간호자연과학회 2004 Journal of korean biological nursing science Vol.6 No.1

Background : Intravenous(Ⅳ) access is becoming an increasingly important part of health care today. The current drive for clinical effectiveness and cost-effective health care serves to increase the need for reliable vascular access. Venous access devices were developed to overcome problems associated with limited peripheral access and frequent venipuncture in patients with long-term therapy. Although the peripherally inserted central catheter(PICC) have become popular during recent years in USA, its procedure is rare in Korea. Purpose : The goal of this study was to analyze the PICC inserted patient data by Ⅳ CNS intervention. Method : A Total of 62 PICCs were inserted into 51 patients by the Ⅳ CNS during a 10-month period form November, 14, 2002, to October 2, 2W2. Data was obtained retrospectively through chart review. Result : The patient population included 34(54.8%) men and 28(45.2%) women, with a mean age 50.6 years. The main indication for PICC placement was to access vein in poor peripheral venous status(40.3%). The mean served interval for PICC insertions was 16.7 days(range, 2~61 days). The reasons for removal were completed therapy in 18 cases(29.0%), patient death in 13 cases(21.0%), and mechanical or functional PICC problem in 10cases(16.1%). The three PICCs removed for presumed infection, and one had only positive tip cultures(0.2%). Conclusion : PICCs are rapidly growing popularity and required an extended course of Ⅳ therapy.

복합 산화법과 MEMS 기술을 이용한 RF용 두꺼운 산화막 에어 브리지 및 공면 전송선의 제조

김국진,박정용,이동인,이봉희,배영호,이종현,박세일 한국센서학회 2002 센서학회지 Vol.11 No.3

본 논문에서는 양극반응과 복합 산화법( H_2O/O_2 분위기에서 500℃, 1시간 열산화와 1050℃, 2분간 RTO(Rapid Thermal Oxidation) 공정)을 이용한 두꺼운 OPSL(Oxidized Porous Silicon Layer)을 형성하여 이를 마이크로머시닝 기술을 이용함으로써 10 ㎛두께의 OPS(Oxidized Porous Silicon) 에어 브리지를 제조하고, 그 위에 전송선로를 형성하여 그 RF 특성을 조사하였다. OPS 에어 브리지 위에 형성된 CPW(Coplanar Waveguide)의 손실이 OPSL 위에 형성된 전송선의 삽입손실보다 약 2 dB 정도 적은 것을 보여주었으며, 반사손실은 OPSL 위에 형성된 전송선의 반사손실보다 적으며 약 -20 dB를 넘지 않고 있다. 본 연구에서 개발한 산화된 다공질실리콘 멤브레인 및 에어 브리지 구조는 CMOS 공정 후에 사용 가능하며, 초고주파 회로 설계시 편리성과 유용성을 제시하고 있다. This paper proposes a 10 ㎛ thick oxide air-bridge structure which can be used as a substrate for RF circuits. The structure was fabricated by anodic reaction, complex oxidation and micromachining technology using TMAH etching. High quality films were obtained by combining low temperature thermal oxidation (500 ℃,1 hr at H_2O/O_2) and rapid thermal oxidation (RTO) process (1050 ℃, 2min). This structure is mechanically stable because of thick oxide layer up to 10 ㎛ and is expected to solve the problem of high dielectric loss of silicon substrate in RF region. The properties of the transmission line formed on the oxidized porous silicon (OPS) air-bridge were investigated and compared with those of the transmission line formed on the OPS layers. The insertion loss of coplanar waveguide (CPW) on OPS air-bridge was (about 2 dB) lower than that of CPW on OPS layers. Also, the return loss of CPW on OPS air-bridge was less than about - 20 dB at measured frequency region for 2.2 mm. Therefore, this technology is very promising for extending the use of CMOS circuitry to higher RF frequencies.

이성분 양이온성 계면활성제 혼합용액의 임계미셀농도에 대한 연구 1. CTAB와 다른 양이온성 계면활성제 CTB 및 DTAB 혼합용액

김진형,오세웅,고정수 木浦大學校基礎科學硏究所 1999 基礎科學硏究誌 Vol.17 No.-

The critical micelle concentration (??) in a micellar state of the mixed surfactant systems of cetyltrimethylammonium bromide (CTAB) with cetylpyridinium bromide(CPB) and dodecyltrimethylammonium bromide (DTAB) were determined at 25℃ as a function of the overall mole fraction of CTAB by the use of surface tension method. CMC values of pure CTAB, CPB, and DTAB were 9.95×10-4 M, ?? M, and ?? M, respectively. Interaction parameterβ value of CPB-CTAB mixture was evaluated as -1.3. In case of DTAB-CTAB mixture, constancy in β value was not obtained over all composition of the mixture.

산업부산물인 Fly Ash의 라이닝콘크리트에의 적용에 관한 실험적 연구

최세진,임정열,정우성,김완영,김무한 공주대학교 자원재활용신소재지역협력센터 2000 2차년도 센터 사업 성과집 Vol.2000 No.1

This is an experimental study to analyze the usability of fly ash in the tunnel lining concrete. For this purpose, the mix proportion of plain concrete and concrete using fly ash(the replacement of 15 and 30% by weight of cement) to satisfy slump 15cm, air content 5% and compressive strength 270kgf/cm2, was selected. And then tests for slump, setting time, compressive strength, tensile strength, drying shrinkage and adiabatic temperature rise were performed. According to test results, it was found that the concrete using fly ash 15% (FA 15 concrete) was better than the plain concrete and FA 30 concrete. FA 15 concrete was more useful than the others in reducing the drying shrinkage : the drying shrinkage strains of FA 15 concrete after 20 weeks of air drying was lower about 10% than the plain concrete, and lower 6% than FA 30 concrete. And the highest compressive strength after curing for 28 days of 365kgf/cm2 was obtained from FA 15 concrete. This was almost 10-20% improvement in compressive sterngth, compare to the plain concrete and FA 30 concrete. And the effect of 5~7.5℃ of concrete using fly ash for hydration heat reducing was calculated. Therefore, concrete using fly ash 15% (FA 15) was expected to improve the performance of lining concrete.