• Macromolecular Research
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• v.10 no.5
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• pp.278-281
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• 2002

We investigated the photoluminescence (PL) characteristics of a highly soluble, fullerene-containing copolymer in both solution and film states. In solution state, the copolymer showed different PL characteristics depending on the aromaticity of the solvent. The PL from polystyrene segments of the copolymer was strongly quenched in an aromatic solvent, while the PL from fullerene remained unchanged. However, the films cast from an aromatic and a nonaromatic solvent demonstrated very similar PL characteristics, implying that the chain alignment or orientation and packing in the films occur in a similar way irrespective of the solvent.

• Journal of the Korean Vacuum Society
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• v.18 no.5
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• pp.365-371
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• 2009

We analyzed photoluminescence (PL) and electroluminescence characteristics of various chirped quantum dot structures. Peaks in EL curves were contributed by excited states of quantum dots (QD), while those in PL curves by grounded states. Based on these characteristics, we suggested that superluminescent diodes with wide spectral bandwidth may be developed if chirped QD structures are designed to make a contribution by ground states to EL characteristics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.27-30
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• 1997

We investigated the electro-optical characteristics of amorphous (a) - twisted nematic (TN) - liquid crystal display (LCD) on polyimide (Pl) films with different polarity. It was found that the threshold voltage of a-TN-LCD is decreased with increasing the polarity of the Pl film. We considered that the threshold voltage in a-TN-LCD is affected to the surface anchoring strength with polarity of the Pl films. Also, we observed the response time of a-TN-LCD on medium polarity of the Pl film is fast compared to high polarity of the Pl film. Finally, we obtained that the viewing angle of a-TN-LCD are almost same on different polarity of the PI films.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.22-22
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• 2003

Studies on the optical properties related to the built-in internal field and the carrier localization present in various GaN-based structures are essential not only for the physical interest but in designing practical visible and ultraviolet light emitting device applications with better performance and quantum efficiency. We report on the optical characteristics of various dimensional GaN-based structures such as (i) GaN self-assembled quantum dots grown in Stranski-Krastanov mode (OD), vertically-aligned GaN nanorods (1D), graded-In-content InGaN quantum wells (2D), laterally-overgrown GaN pyramids (3D), and GaN epilayers grown on various substrates. We used a wide variety of optical techniques, such as photoluminescence (PL), PL excitation, micro-PL, cathodoluminescence, optically-pumped stimulated emission, and time-resolved PL spectroscopy. An overview and comparison of the optical characteristics of the above GaN-based structures will be given.

• Current Optics and Photonics
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• v.3 no.2
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• pp.164-171
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• 2019

Photoluminescence (PL) properties of GaN-based light-emitting diodes (LEDs) were analyzed to study the effects of carrier leakage on the luminescence properties at room temperature. The electrical leakage and PL properties were compared for LEDs showing leakages at forward bias and an LED with an intentional leakage path formed by connecting a parallel resistance of various values. The leakages at the forward bias, which could be observed from the current-voltage characteristics, resulted in an increase in the excitation laser power density for the maximum PL efficiency (ratio of PL intensity to excitation power) as well as a reduction in the PL intensity. The effect of carrier leakages on PL properties was similar to the change in PL properties owing to a reduction of the photovoltage by a reverse current since the direction of the carrier movement under photoexcitation is identical to that of the reverse current. Valid relations between PL properties and electrical properties were observed as the PL properties deteriorated with an increase in the carrier leakage. The results imply that the PL properties of LED chips can be an indicator of the electrical properties of LEDs.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.2
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• pp.22-30
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• 2017

PL (Product Liability) refers to the legal responsibility of a manufacturer or seller for bodily injuries or property losses caused by product defects. Therefore, it is important for companies to construct a product liability response system that strategically manage and effectively adapt to product liability. A PL response system refers to companywide operations of PL prevention (PLP) measures, product safety (PS) measures, and PL defense (PLD) measures appropriate for a company's scale and environment. To establish an enterprise product liability response system, each essential component of corporations should be systematically operated and maintained considering the scale and characteristics of the corporations. Essential components of PL response system is Strategy, Organization, Training, Technology, Investment, and Awareness. Role of essential components is that companies need specific strategies to secure product safety and protect customers from product defects, and appropriate organizations must be composed for effective operation of such strategies. The objective of this paper seeks to examine the relationships among the essential components of the product liability response system and PL performance. PL performance consists of positive performance and negative performance. In particular, positive performance include increased efforts in product or process innovation such as strengthening research and development (R&D) to produce safer products without defects. In order to carry out this research we obtained 98 questionnaire of manufacturing company. A summary of the analyses is as follows: First, the awareness and technology among essential components affect significantly to the positive performance. Second, the awareness and strategy among essential components negative affect to the negative performance.

• Korean Journal of Food Science and Technology
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• v.37 no.2
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• pp.247-254
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• 2005

General composition, total anthocyan content, and antioxidative and antimicrobial activities of Korean purple. fleshed potatoes (varieties A-D based on coloring degree of cross sections) were investigated. Slight differences in composition content were observed among varieties. Color intensity analyzed by sensory evaluation test decreased in order of PL-14, 31, 28, 3, 17, and 6, Total anthocyanin contents differed significantly among varieties from 3 to 29 mg Per 100 g, and decreased in order of PL-28, 31, 14, 12, 5, and 3. PL-28, 31, and Jasim potatoes showed slightly higher antioxidant activities than ${\alpha}$-tocopherol. PL-28, 31, 6, and Jasim showed antimicrobial activities against three species each of Gram-positive and-negative bacteria, with highest activities observed against Bacillus subtilis and relatively high activities against E. coli.

• Food Science of Animal Resources
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• v.25 no.1
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• pp.52-59
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• 2005

This study was performed to investigate physicochemical and textural characteristics, and antimicrobial effect for Listeria monocytogenes (LM) in low-fat functional sausages (LFFS) containing sodium lactate (SL) and potassium lactate (PL) during storage at 4℃ for 10 weeks. The LFFS treatments included CTL (Low-fat sausage control), TRT1 (SL 3.3%), TRT2 (SL 2.2% + PL 1.1%), TRT3 (SL 1.1% + PL 2.2%), TRT4 (PL 3.3%). Proximate composition for LFFS were 73.9∼75.2% moisture, 1∼2% fat and 15.5∼15.9% protein, and pH values ranged from 5.8 to 6.5. Expressible moisture (EM, %) and vacuum purge (VP, %) ranged from 22.9 to 33.0 and from 2.7 to 5.3, respectively. EM of CTL, TRT1 and TRT2 increased with increased storage time, however, no differences in VP were observed during storage time. Hunter color values (L, a, b) were not affected by the addition of SL and PL, and storage time (p>0.05). Most textural properties of LFFS were not affected by the addition of SL and PL, except for few cases, but those of CTL tended to increase with increased storage time. The addition of SL and PL into LFFS, alone or in combination, inhibited the microbial growth of inoculated LM during refrigerated storage, resulting in longer shelf-life than the control.

• Journal of Distribution Science
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• v.18 no.10
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• pp.121-130
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• 2020

Purpose: In this study we investigate the determinants of private label (PL) purchase intention in South Korea. Private labels are becoming more and more popular in America and European countries. However, there are not enough studies focusing on PL within the South Korean market. Therefore, the present study has been written in order to understand more about consumers' purchase intention of store brand in the South Korean market. Many characteristics and aspects of consumers and brand's behavior have been reviewed in order to bring relevant results. Research design, data and methodology: Data was collected using a quantitative survey of Korea retail store's consumer. We analyzed using multiple regression method to test the hypothesis. We analyzed how and why do consumers have a strong intention to purchase the PL. Results: a) Trust towards retailer influences the PL purchase intention of customers; b) brand awareness has an impact on the PL purchase intention of customers; c) perceived quality has an impact on the PL purchase intention; d) Price-quality relationship influences on the PL purchase intention. However, there is no direct effect of some of the factors of determinant. Conclusion: For private label products in the Korean market, trust in sellers and brand awareness influences the purchase of PL products.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.122-122
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• 2010

ZnO is a widely investigated material for the blue and ultraviolet solid-state emitters and detectors. It has been promoted due to a wide-band gap semiconductor which has large exciton binding energy of 60 meV, chemical stability and low radiation damage. However, there are many problems to be solved for the growth of p-type ZnO for practical device applications. Many researchers have made an efforts to achieve p-type conductivity using group-V element of N, P, As, and Sb. In this letter, we have studied the optical characteristics of the antimony-doped ZnO (ZnO:Sb) thin films by means of photoluminescence (PL), PL excitation, temperature-dependent PL, and time-resolved PL techniques. We observed donor-to-acceptor-pair transition at about 3.24 eV with its phonon replicas with a periodic spacing of about 72 meV in the PL spectra of antimony-doped ZnO (ZnO:Sb) thin films at 12 K. We also investigate thermal activation energy and carrier recombination lifetime for the samples. Our result reflects that the antimony doping can generate shallow acceptor states, leading to a good p-type conductivity in ZnO.