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검색결과 284건 처리시간 0.032초

Investigation of Firing Conditions for Optimizing Aluminum-Doped p+-layer of Crystalline Silicon Solar Cells

  • Lee, Sang Hee;Lee, Doo Won;Shin, Eun Gu;Lee, Soo Hong
    • Current Photovoltaic Research
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    • 제4권1호
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    • pp.12-15
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    • 2016
  • Screen printing technique followed by firing has commonly been used as metallization for both laboratory and industrial based solar cells. In the solar cell industry, the firing process is usually conducted in a belt furnace and needs to be optimized for fabricating high efficiency solar cells. The printed-Al layer on the silicon is rapidly heated at over $800^{\circ}C$ which forms a layer of back surface field (BSF) between Si-Al interfaces. The BSF layer forms $p-p^+$ structure on the rear side of cells and lower rear surface recombination velocity (SRV). To have low SRV, deep $p^+$ layer and uniform junction formation are required. In this experiment, firing process was carried out by using conventional tube furnace with $N_2$ gas atmosphere to optimize $V_{oc}$ of laboratory cells. To measure the thickness of BSF layer, selective etching was conducted by using a solution composed of hydrogen fluoride, nitric acid and acetic acid. The $V_{oc}$ and pseudo efficiency were measured by Suns-$V_{oc}$ to compare cell properties with varied firing condition.

Detection of estrogenic hormone 17β-estradiol in soil samples by a recombinant yeast bioassay and supercritical fluid extraction

  • Shim, Jae-Han;Kim, Mi-Ra;Topp, Edward;Choi, Jeong-Heui;Mamun, Iqbal Rouf
    • 한국환경농학회지
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    • 제27권4호
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    • pp.447-455
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    • 2008
  • Recombinant yeast estrogenicity (YES) assay was used as a bioanalytical tool in order to screen $17{\beta}$-estradiol in the soil samples collected from different sites of South Korea. Solvent extraction and supercritical fluid extraction (SFE) methods were compared for the extraction of the estradiol from the soils. Most high detection of the estradiol based on YES assay was observed in the soils extracted with methanol. Different types of estrogenic hormones including $17{\beta}$-estradiol were suggested to be possibly exiting in the soils, since the methanol extracts of the soils showed an estrogenic activity that was not observed in the hexane extracts of the soil. SFE extracts showed estrogenic activity in some of the samples but methanol extract showed best activity.

공단지역에서 생육하는 가로수 27종의 항산화특성과 잠재적 환경정화능력 (Antioxidant Characteristics and Phytoremediation Potential of 27 Taxa of Roadside Trees at Industrial Complex Area)

  • 한심희;이재천;오창영;김판기
    • 한국농림기상학회지
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    • 제8권3호
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    • pp.159-168
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    • 2006
  • 대기오염물질을 정화하기에 적합한 수종을 탐색하기 위하여, 공단지역의 가로수로 식재된 27개 수종의 잎에서 항산화 능력, 과산화 지질 함량 및 질소함량을 조사하였다. 2깨 수종 중 항산화 능력이 가장 높은 수종은 개잎갈나무(91.4%) 이었고, 가장 낮은 수종은 벽오동(56.9%) 이었다. MDA함량이 가장 적은 수종은 배롱나무와 은행나무였으나, 양버즘나무, 구실잣밤나무, 후박나무 및 향나무에서는 높은 MDA 함량이 측정되었다. 낙엽활엽수의 항산화 능력은 상록수의 항산화 능력과 뚜렷한 차이가 없었으나, 낙엽활엽수의 MDA 함량은 상록수의 MDA 함량보다 낮게 나타났다. 27개 수종은 항산화 능력과 과산화지질 함량을 기준으로 하여 다음과 같이 4개의 범주로 구분하였다. 범주 I은 높은 항산화 능력과 낮은 과산화지질 함량을 가진 수종, 범주 II는 높은 항산화 능력과 높은 과산화지질 함량을 가진 수종, 범주 III은 낮은 항산화 능력과 낮은 과산화지질 함량을 가진 수종, 범주 IV는 낮은 항산화 능력과 높은 과산화 지질 함량을 가진 수종. 이들 4개 범주에 속하는 수종은 각각 7종(범주 I), 6종(범주 II), 8종(범주 3), 6종(범주 IV) 이었다. 높은 항산화 능력을 가진 범주 I과 II의 수종들은 낮은 질소함량을 나타냈으나, 낮은 항산화능력을 가진 범주 III과 IV의 수종들은 높은 질소함량을 나타냈다. 그러나 범주 I과 II에 속하는 메타세코이아, 굴피나무, 양버즘나무는 예외적으로 높은 항산화 능력과 높은 질소함량을 나타냄으로써 이들 수종들은 공단지역의 식재 수종으로 적합한 것으로 판단되었다.

Room temperature-processed TiO2 coated photoelectrodes for dye-sensitized solar cells

  • Kim, Dae-gun;Lee, Kyung-min;Lee, Hyung-bok;Lim, Jong-woo;Park, Jae-hyuk
    • 한국결정성장학회지
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    • 제30권2호
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    • pp.61-65
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    • 2020
  • The depletion of fossil fuels and the increase in environmental awareness have led to greater interest in renewable energy. In particular, solar cells have attracted attention because they can convert an infinite amount of solar energy into electricity. Dye-sensitize solar cells (DSSCs) are low cost third generation solar cells that can be manufactured using environmentally friendly materials. However, DSSC photoelectrodes are generally produced by screen printing, which requires high temperature heat treatment, and low temperature processes that can be used to produce flexible DSSCs are limited. To overcome these temperature limitations, this study fabricated photoelectrodes using room-temperature aerosol deposition. The resulting DSSCs had an energy conversion efficiency of 4.07 %. This shows that it is possible to produce DSSCs and flexible devices using room-temperature processes.

스테인리스 스틸-나트륨 히트파이프의 장기 수명 시험 (Long-Term Life Test of A Stainless Steel-Sodium Heat Pipe)

  • 박수용;정의국;부준홍;강환국;유정현;박상훈
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.1058-1062
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    • 2004
  • High-temperature cylindrical stainless steel/sodium heat pipe was manufactured and tested under long-term operation. The container material was stainless steel 316L and the working fluid was sodium. The heat pipe was 25.4 mm in diameter and 1000 mm in length with a two-layer screen mesh wick. The evaporator part was 600 mm and the condenser part was 300 mm in length. Total measurement points on heat pipe were 15 points and 12 points were located in condenser part. The heat pipe was heated for 142 days(3400 hours) at $800^{\circ}C$. In the test period, the maximum temperature difference was increased from $18^{\circ}C$ o $28^{\circ}C$ and the maximum thermal resistance was as low as $0.015^{\circ}CW$.

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토직, 상토 및 양액육묘에 의해 생산된 묘삼의 본포 이식 후 생장특성 (Growth Characteristics of Ginseng Seedling Transplanting by Self Soil Nusery, Nursery or Hydroponic Culture on Main Field)

  • 박홍우;송정호;권기범;이응호;손호준
    • 한국약용작물학회지
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    • 제25권4호
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    • pp.238-243
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    • 2017
  • Background: The production method of ginseng seedlings for ginseng cultivation is very important to ensure healthy rooting system as well as high quality, and yield of the resultant plants. This study was carried out to compare the growth characteristics of 2-year-old ginseng plants that were produced from seedlings grown in self soil nursery (SSN), nursery soil (NS) or hydroponic culture (HC). Methods and Results: The shading prop used was composed of four-layered 4 polyethylene (blue 3 + black 1) shade screen. The management of main field was done by inserting oil cake (1,200 kg/10 a) and then allowing Sudan grass to grow for a year. Seedling transplantation was carried out on April 6. Root growth was measured on October 25. Root weight was observed to be excellent at 6.0 g, following SSN transplantation. Root length was 21.2 cm for HC seedlings, but these plants had a physiological disorder (i.e., rusty root), in 83.5% plants of this treatment. The ratio of PD/PT (protopanaxadiol saponins / protopanaxatriol saponins) was higher in NS seedlings. Plant analysis revealed that Fe content was lower in HC seedlings with high rustiness. The growth of 2-years-old ginseng was different following these varying seedling cultivation methods, but seedlings from NS were not different from those grown in SSN. Conclusions: For the propagation of 2-year-old ginseng plants, NS seedlings may be a good substitute for SSN seedlings.

셀룰로오스 혼방 니트 편포의 착색번아웃 날염복합기술에 관한 연구 (A Study on the Cellulose Blend Knit Fabrics using Burn-out Printing Convergence Technology)

  • 조호현;정명희;이종렬
    • 한국의상디자인학회지
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    • 제16권4호
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    • pp.229-235
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    • 2014
  • This study conducted a research on burn-out printing convergence technology for cellulose blend knit fabrics. Printing technology, which forms color pattern on the fabric, can be generally classified into four according to printer or printing method, e.g. screen printing, roller printing, rotary printing, digital printing. However, these printing methods are flat in design or pattern, which have limitation to overcome monotonousness of fabric, so that recently burn-out process method, which expresses three-dimensional pattern effect by treating chemical on the surface of fabric as the method to appeal its esthetics to the customers. Particularly, in case of cellulose/polyester composite material, first, it is proceeded in 2 processes, by dyeing cellulose or polyester fabric and burning out cellulose fabric, in this process, due to pollution caused by disperse dye migration, color of polyester fabric part could be discolored, which has high falt risk. This research considered coloring burn-out technique, which simultaneously proceed dyeing and burn-out by reducing dyeing and burn-out process to 1 stage, which were proceeded in 2 stages previously. As the research result, it was confirmed that reasonable depth of roller was 0.04~0.06mm in roller printing process, heat treatment condition of burn-out far-infrared radiation was $185^{\circ}C{\times}30m/min$. Color fastness to washing was confirmed to be 4-5 grade, color fastness to rubbing, 3-4 grade, color fastness to light, 4 grade. Also, it was confirmed that energy reduction effect appeared 38.19%, in case of energy cost per yard compared to the existing production, also, 19.74%, in case of production cost.

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한국 신장이식 대기자의 심리사회적 평가 및 영향 요인 (Psychosocial Assessment and Related Factors for Kidney Transplantation Candidates in South Korea: A Descriptive Correlational Study)

  • 정혜진
    • Journal of Korean Biological Nursing Science
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    • 제21권4호
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    • pp.249-258
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    • 2019
  • Purpose: The purpose of this study was to assess the psychosocial status of candidates for deceased donor kidney transplantation (DDKT) in South Korea and identify factors associated with high-risk psychosocial status. Methods: The descriptive cross-sectional design included application of a standardized transplantation-specific assessment tool, the Psychosocial Assessment Candidacy Transplantation (PACT) instrument, and review of candidates' medical records. A total of 157 patients awaiting DDKT were recruited from a Korean organ transplantation center. The collected data were analyzed using descriptive statistics and binary logistic regression. Candidates were divided into high- and low-psychosocial risk groups using 3 as the cutoff point of PACT. Results: The mean score for the PACT final rating was 2.10, and the lowest average subscale score was 2.30 for understanding the processes of transplantation and follow up. Poor physical candidacy, especially due to comorbidities, and older age were associated with high psychosocial risk. Conclusion: The results of this study showed that the psychosocial status of Korean DDKT candidates was problematic. Development of systematic management programs for effective clinical strategies in the care of candidates is crucial to maintain their desirable psychosocial status in case of an emergency DDKT operation and improve post-transplantation outcomes. Continuous education is absolutely necessary to enhance understanding of the transplantation process for high-risk psychosocial candidates. Additionally, nurses and transplantation professionals should screen candidates with high-risk psychosocial status early in the process using transplantation-specific assessment tools and provide intensive interventions, particularly for poor physical candidacy patients and older candidates.

Lung Cancer Detection by Screening - Presenting Circulating miRNAs as a Promising Next Generation Biomarker Breakthrough

  • Ramshankar, Vijayalakshmi;Krishnamurthy, Arvind
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권4호
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    • pp.2167-2172
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    • 2013
  • Lung cancer remains a major cause of morbidity and mortality worldwide, accounting for more deaths than any other cause. All the clinical practice guidelines recommended against routine screening for lung cancer have cited lack of robust evidence, at least until a few years back. However, the potential to screen lung cancers has received renewed interest due to superior performance of low dose CT (LD-CT) in detecting early stage cancers. The incremental costs and risks involved due to the invasive procedures in the screened population due to a high false positivity rate questions the use of LD-CT scan as a reliable community based screening tool. There is therefore an urgent need to find a less invasive and a more reliable biomarker that is crucial to increase the probability of early lung cancer detection. This can truly make a difference in lung cancer survival and at the same time be more cost and resource utilization effective. Sampling blood serum being minimally invasive, low risk and providing an easy to obtain biofluid, needs to be explored for potential biomarkers. This review discusses the use of circulatory miRNAs that have been able to discriminate lung cancer patients from disease free controls. Several studies conducted recently suggest that circulating miRNAs may have promising future applications for screening and early detection of lung cancer.

새로운 방향족 에스테르계 가소제 합성 및 내분비계 장애성 시험 (Synthesis of New Aromatic Ester Plasticizers and Their Endocrine Disrupting Screening)

  • 유경호;류재천
    • 한국응용과학기술학회지
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    • 제24권3호
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    • pp.211-218
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    • 2007
  • Based on the Benzoflex (Vesicol Chemical Co.) as PVC plasticizer substituents for Di-n-octyl phthalate (DOP), a series of new aromatic carboxylic acid ester compounds were designed as plasticizers, synthesized, and screened for the endocrine disrupting activity. 2-Hydroxybenzoic acid (1) and 2-methoxybenzoic acid (2) as the commercially available starting materials were reacted with diethylene glycol (3) in the presence of p-toluenesulfonic acid using Dean-Stark column to give diethylene glycol di-(2-hydroxy)benzoate (4, KH01) and diethylene glycol di-(2-methoxy)benzoate (5, KH02), respectively. And diethylene glycol di-(3-pyridinyl) ester (7, KH03) and dipropylene glycol di-(3-pyridinyl) ester (9, KH04) were obtained in high yields by treatment of nicotinoyl chloride (6) with diethylene glycol (3) and dipropylene glycol (8) in the presence of triethylamine as a base. To determine the estrogenic disrupting effect of new synthetic phthalate analogues, E-screen assay method was used. Of these compounds, 4 (KH01) was found to be compound without endocrine disrupting effect.