• Journal of Electrochemical Science and Technology
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• v.1 no.2
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• pp.69-74
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• 2010

Methodologies to improve photovoltaic performance of dye-sensitized solar cell (DSSC) are reviewed. DSSC is usually composed of a dye-adsorbed $TiO_2$ photoanode, a tri-iodide/iodide redox electrolyte and a Pt counter electrode. Among the photovoltaic parameters of short-circuit photocurrent density, open-circuit voltage and fill factor, short-circuit photocurrent density is the collective measure of light harvesting, charge separation and charge collection efficiencies. Internal quantum efficiency is known to reach almost 100%, which indicates that charge separation occurs without loss by recombination. Thus, light harvesting efficiency plays an important role in improvement of photocurrent. In this paper, technologies to improve light harvesting efficiency, including surface area improvement by nano-dispersion, size-dependent light scattering efficiency, bi-functional nano material, panchromatic absorption by selective positioning of three different dyes and transparent conductive oxide (TCO)-less DSSC, are introduced.

• Journal of ILASS-Korea
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• v.11 no.2
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• pp.98-104
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• 2006

A charged droplet scrubber was introduced to remove visible smokes generated in many industrial facilities. Lab-scale and field tests were conducted in this study. The system consists of a corona discharger to effectively charge the fine particles, fellowed by an electrostatic chamber to promote coagulation between charged fine particles and oppositely charged droplets and a demister to remove resultant particles. Overall collection efficiency, 98.4% was obtained from a lab-scale test, when a high voltage was applied to an ionizer and a charged droplet scrubber. Field tests also show the high collection efficiencies, 93.5% with one stage and 99.4% with two stage system. This system can be used to increase the collection efficiency of the conventional air pollution control devices to satisfy the national emission standard.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.453-455
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• 1995

In electrostatic airclean filter, the collection efficiency defends on particle charge in the ionizer section. The effect of electrostatic airclean filter condition (deposition of dust, variation of corona discharge current) on corona discharge characteristics was well studied. However, it seems not to be studied on corona discharge characteristics of electrostatic airclean filter respect to contaminated electrode which is caused by practical use. In this paper, Long-term(60days) effects are studied experimentally by two methods. The one is ozone concentration, the other is collection efficiency. Generation of ozone level was increased but collection efficiency was slightly reduced in long-term used electrostatic airclean filter.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.11
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• pp.1059-1064
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• 2001

This study Investigates the effect of the wave form of pulse energization on the collection characteristics of a wide plate spacing electrostatic precipitator. For the semi-pulse energization, the peak current and voltage of the energization increases with increase of the pulse period, and the corona current increases, as pulse ratio decreases. For the micro-pulse energization, the corona current increases with increase of the pulse voltage. The collection efficiency of semi-pulse and micro-pulse energization is larger than that of DC charge.

• Korean Journal of Human Ecology
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• v.22 no.6
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• pp.571-586
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• 2013

The purpose of this study was to examine educational meanings of snack and lunch time of 4-year-old children and their teachers in a kindergarten class. The study was done in the Class of 4-year-old children in S Kindergarten located in Songpa-gu, Seoul. And 30 children of this class, Teacher A who is the teacher in charge of the Class, and Teacher B who is the researcher and teacher in charge of it participated in it. The study was carried out by the ethnography method and data collection was done through participation observation, interviews, video and voice recording, and data collection of photography shooting. The results are as follow: First, the children had private conversations, shared their cultures, deepened and expanded their existing concepts, expressed their emotions and relieved their tension, and strengthened relations with friends during the snack and lunch time. Second, the teachers promoted conversation and communication, gave the opportunity that the children can set the lunch table by themselves and tried to make the snack and lunch time with the children by discussing what they are how they are operated with them together. In conclusion, the snack and lunch time can be more meaningful time for children when there are proper educational plans and support of teachers which are considered children's viewpoints.

• Journal of Environmental Health Sciences
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• v.20 no.4
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• pp.60-71
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• 1994

The average volume of waste per a person in Korea is exceedingly higher than that of Europeans. But the social movement for the resources recycling and the environmental conservation makes the people play their part in several activities like the Separate Collection System. At the time of this agitation, Korean central government brought the Volume Based Waste Charge System into operation in some regions on a trial basis having full-scale operation nationwidely near at hand. Andong City which is one of points under trial operation had remarkble result during this term in resources recycling as well as wastes reducing. The wastes' diminution reached to 32.0 % and the resources recycling was increased by 13.7 times. The responses from the 701 housewives in Andong were also very stimulative. The neccesity of this system was judged conclusively by 91.6 % of total answerers. Also this system was considered as a successful one by 78.4 % popular support. But not little portion (53.8 %) of the answerers felt that the detail methods of this system were unconvenient. In order to take root this system in it's early stages, the Separate Collection should be carried out perfectly and systematically with top priority. And the next program should be the improvement of the detail methods in this system.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.72-72
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• 2010

Recent development of organic solar cell approaches the level of 8% power conversion efficiency by the introduction of new materials, improved material engineering, and more sophisticated device structures. As for interface engineering, various interlayer materials such as LiF, CaO, NaF, and KF have been utilized between Al electrode and active layer. Those materials lower the work function of cathode and interface barrier, protect the active layer, enhance charge collection efficiency, and induce active layer doping. However, the addition of another step of thin layer deposition could be a little complicated. Thus, on a typical solar cell structure of Al/P3HT:PCBM/PEDOT:PSS/ITO glass, we used Li:Al alloy electrode instead of Al to render a simple process. J-V measurement under dark and light illumination on the polymer solar cell using Li:Al cathode shows the improvement in electric properties such as decrease in leakage current and series resistance, and increase in circuit current density. This effective charge collection and electron transport correspond to lowered energy barrier for electron transport at the interface, which is measured by ultraviolet photoelectron spectroscopy. Indeed, through the measurement of secondary ion mass spectroscopy, the Li atoms turn out to be located mainly at the interface between polymer and Al metal. In addition, the chemical reaction between polymer and metal electrodes are measured by X-ray photoelectron spectroscopy.

• Journal of Korean Critical Care Nursing
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• v.14 no.3
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• pp.99-112
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• 2021

Purpose : This study aimed to comprehensively understand the work experience of the person in charge of the adequacy evaluation of small-and medium-sized hospitals and explore its meaning and essence in-depth. Methods : This was a descriptive qualitative study. The study participants were 10 nurses who understood the purpose of this study and participated voluntarily. Data collection was conducted via in-depth interviews in January 2021. The interviews were conducted 1-2 times per participant and lasted approximately 40-50 minutes per session. Data analysis was performed using a qualitative content analysis. Results : The work experience of the person in charge of the adequacy evaluation of small-and medium-sized hospitals included four themes: "difficulty in preparing for evaluation," "negative views on evaluation," "lack of a support system," and "positive improvements and changes due to an evaluation." Conclusion : Based on the above results, an education program and support system should be developed to strengthen the competence of nurses in charge of the adequacy evaluation of small- and medium-sized hospitals.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.99.2-99.2
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• 2011

Transparent conducting oxides (TCOs) supported on glass are widely used as substrates in PEC studies for photovoltaic hydrogen generation applications However, high sheet resistane ($10{\sim}15{\Omega}/cm^2$) and fragileness of glass-supported TCO substrates are the obstacles to produce the large area PEC cells. Such internal sheet resistance is detrimental to efficient collection of photogenerated majority charge carriers at the photoactive material and electrolyte interface. Moreover, these TCO substrates are very expensive and consume about 40~60% cost of the devices. Hence, a low sheet resistance of the substrate is a key point in improving the performance of PEC devices. Metallic substrates coated with a photoactive material would be a good choice for efficient charge collection. Such metal substrates based photanodes are best candidate for large-scale phtoelectrochemical water splitting for hydrogen generation. In this study, we report the enhanced PEC performance of $WO_3$ film on metal(chemical etched, bare) substrate. It is proposed that interface between $WO_3$ and the metal substrate is responsible for efficient charge transfer and demonstrated significant improvement in the photoelectrochmical performance. X-ray diffration and FESEM suduies reveled that $WO_3$ films are monoclinic, porous, polycrystalline with average grain size of ~50nm. Photocurrent of $WO_3$ prepared on metal substrates was measured in 0.5M $H_2SO_4$ electroyte under simulated $100mW/cm^2$ illumination.

• Journal of the Korean Society for Library and Information Science
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• v.53 no.4
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• pp.399-418
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• 2019

In accordance with the recent expansion of collection operation of independent publications through public libraries, this study conducted a status analysis on independent publications collection in public libraries and in-depth interviews with staff in charge of independent publications in order to suggest ways to effectively manage independent publications. As a result, it was deduced that the measures needed for effective management of independent publications are construction of joint cataloging system for building and sharing independent publications catalog in public libraries; platform for collecting various information of independent publications; support for ISBN, ISSN, CIP issuance of independent publications; and improvement of distribution system.