• Current Photovoltaic Research
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• 제4권1호
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• pp.1-7
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• 2016

Among the various types of solar cells, silicon based two terminal tandem solar cell is one of the most popular one. It is designed to split the absorption of incident AM1.5 solar radiation among two of its component cells, thereby widening the wavelength range of external quantum efficiency (EQE) spectra of the device, in comparison to that of a single junction solar cell. In order to improve the EQE spectra further and raise short circuit current density ($J_{sc}$) an optimization of the tradeoff between the top and bottom cell is needed. In an optimized cell structure, the $J_{sc}$ and hence efficiency of the device can further be enhanced with the help of light trapping scheme. This can be achieved by texturing front and back surface as well as a back reflector of the device. In this brief review we highlight the development of light trapping in the silicon based tandem solar cell.

• Applied Microscopy
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• 제46권3호
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• pp.127-133
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• 2016

Atom probe tomography is a time-of-flight mass spectrometry-based microanalysis technique based on the field evaporation of surface atoms of a tip-shaped specimen under an extremely high surface electric field. It enables three-dimensional characterization for deeper understanding of chemical nature in conductive materials at nanometer/atomic level, because of its high depth and spatial resolutions and ppm-level sensitivity. Indeed, the technique has been widely used to investigate the elemental partitioning in the complex microstructures, the segregation of solute atoms to the boundaries, interfaces, and dislocations as well as following of the evolution of precipitation staring from the early stage of cluster formation to the final stage of the equilibrium precipitates. The current review article aims at giving a comment to first atom probe users regarding the limitation of the techniques, providing a brief perspective on how we correctly interprets atom probe data for targeted applications.

• Mycobiology
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• 제45권4호
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• pp.233-239
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• 2017

Drosophila melanogaster is a useful model organism that offers essential insights into developmental and cellular processes shared with humans, which has been adapted for large scale analysis of medically important microbes and to test the toxicity of heavy metals, industrial solvents and other poisonous substances. We here give a brief review of the use of the Drosophila model in medical mycology, discuss the volatile organic compounds (VOCs) produced by the opportunistic human pathogen, Aspergillus fumigatus, and give a brief summary of what is known about the toxicity of some common fungal VOCs. Further, we discuss the use of VOC detection as an indirect indicator of fungal growth, including for early diagnosis of aspergillosis. Finally, we hypothesize that D. melanogaster has promise for investigating the role of VOCs synthesized by A. fumigatus as possible virulence factors.

• 영어어문교육
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• 제7권2호
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• pp.17-36
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• 2002

This article begins by exploring recent developments in the use of the world wide webs in language testing about what a Web-based language test (WBT) is and how they are used in language testing. After a brief review of computer-based testing, WBTs are defined and categorized as low-tech or high tech. Since low-tech tests are the more feasible, they will constitute the focus of this paper. Next, item types for low-tech WBTs are described, and validation concerns that are specific to WBTs are discussed. After a brief overview of the combination of computer-adaptive and Web-based tests, the general advantages as well as design and implementation issues of WBTs are considered before examining the role that testing consequences play in deciding whether a WBT is an appropriate assessment instrument. It is argued that WBTs are most appropriate in low-stakes testing situations; but with proper supervision, they can also be used in medium-stakes situations although they are not generally recommended for high-stakes situations. Some possible ideas for future research are suggested.(169)

• 품질경영학회지
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• 제21권1호
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• pp.44-54
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• 1993

Factory Automation is being implemented rapidly in almost of industries. This new trend and technology have a great influence on even traditional quality control system, and make it be changed with new approaches and methodologies. In these environments, this study has brief review on automation and quality control system, gives checkpoints of the automation system design with the viewpoint of quality control. Also this study proposes a detail system configuration and specifications of each system conponent in the configuration. In the last, a brief implementation guideline for the automation system in the scope of information technology is also presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2100-2102
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• 2005

In this Paper, there have been brief review about the important consideration in laboratory planning and designing the dielectric testing facilities for heavy electric apparatus up to 800kV-class in the high voltage testing fields. To improve and reinforce the existing dielectric test facilities in the way of econo-mical and optimal condition, wide investigation and an analysis for a solution, especially overshoot compensation method. have been suggested. With the brief description about those matters in constructing and improving the test facilities, the specification of each facility has been shown in the paper.

• 한국항만학회지
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• 제5권1호
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• pp.3-22
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• 1991

In recent years the hatchcoverless(or open-top) containerships have been evolving as a promising new concept for enhanced containership operations. The design concept of the hatchcoverless containership is innovative and appears to be worthwhile. especially from an operational viewpoint. The hatchcover and container lashing system have been eliminated and the containers are stacked in open hold fitted with cell guides. Thus this design concept can provide a more efficient and economically viable fleet due to the reduced time and cost of loading and unloading operations. Therefore turnaround time in port is also greatly reduced. This examination provides. brief background, advantages, brief review of new building containership, highlights of the pertinent areas requiring special consideration and recommendations of possible analyses herein.

• 비파괴검사학회지
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• 제9권2호
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• pp.25-36
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• 1989

This essay is a general review of the application of ultrasonic NDE techniques to the performance assessment and characterization of composite materials. A brief review of ultrasonic input-output characterization of a composite plate by shear waves is presented. A theoretical development of ultrasonic wave propagation in isotropic and anisotropic media excited, respectively, by a circular transducer and an oscillatory point source is summarized. Some experimental results are described in which ultrasonic velocity and attenuation measurements give insight into material degradation of fatigued composite laminates. Ultrasonic determination of the elastic constants of a composite plate and an experimental attempt at ultrasonic testing of an isotropic plate containing a crack are also included. A recent effort for the characterization of viscoelastic materials using the ultrasonic NDE technique is outlined. Finally, the reliability of ultrasonic NDE is briefly touched upon.

• 센서학회지
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• 제29권4호
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• pp.220-226
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• 2020

Graphene has been widely considered a promising candidate for high-quality chemical sensors, owing to its outstanding characteristics, such as sensitive gas adsorption at room temperature, high conductivity, high flexibility, and high transparency. However, the main drawback of a graphene-based gas sensor is the necessity for external heaters due to its slow response, incomplete recovery, and low selectivity at room temperature. Conventional heating devices have limitations such as large volume, thermal safety issues, and high power consumption. Moreover, metal-based heating systems cannot be applied to transparent and flexible devices. Thus, to solve this problem, a method of supplying the thermal energy necessary for gas sensing via the self-heating of graphene by utilizing its high carrier mobility has been studied. Herein, we provide a brief review of recent studies on self-activated graphene-based gas sensors. This review also describes various strategies for the self-activation of graphene sensors and the enhancement of their sensing properties.

• 산업공학
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• 제11권1호
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• pp.1-14
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• 1998

Various problems on logistics systems have been dealt with recently as research issues since they were regarded critical for taking up a better position in the increasingly competitive global market. In particular, the freight transportation is considered as a key factor which affects the economic competitiveness of a whole nation as well as the production cost of individual companies. The objective of this study is to identify main issues and review recent foreign and domestic studies related to the freight transportation. The studies are classified into two categories according to the hierarchical level in the decision making process: infra structure design and transportation strategies, service design and operation. Main issues are introduced with a brief review on the related literature and methodologies applied.