• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.4
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• pp.564-570
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• 1996

We have observed the red and blue luminescence from porous silicon (PS) without any rapid thermal oxidation. Aged porous silicon specimens prepared in dilute HF concentration, especially for the short duration of etching, display the increase of the blue band. The measured luminescence decay time at room temperature exhibits a decay time of about 100 ps and shows appreciably faster decay time than that of 20 K. No photoluminescence (PL) peak maximum shift is observed for the blue PL band at 77 K. However, the red PL band shows the blue shift and displays yellow luminescence at 77 K. The origin of red luminescence has some properties related to Si crystallites, whereas blue luminescence seems to be associated other than Si crystallites.

• Macromolecular Research
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• v.16 no.4
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• pp.329-336
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• 2008

Core/shell ($\pm$)PS/(-)silica nanocomposite particles were synthesized by dispersion polymerization using an amphoteric initiator, 2,2'-azobis [N-(2-carboxyethyl)-2,2-methylpropionamidine] ($HOOC(CH_2)_2HN$(HN=) $C(CH_3)_2CN$=NC $(CH_3)_2C$(=NH)NH $(CH_2)_2COOH$), VA-057. Negatively charged (-6.9 mV) silica was used as the stabilizer. The effects of silica addition time and silica and initiator concentrations were investigated in terms of polymerization kinetics, ultimate particle morphology, and size/size distribution. Uniform hybrid microspheres with a well-defined, core-shell structure were obtained at the following conditions: silica content = 10-15 wt% to styrene, VA-057 content=above 2 wt% to styrene and silica addition time=0 min after initiation. The delay in silica addition time retarded the polymerization kinetics and broadened the particle size distribution. The rate of polymerization was strongly affected by the silica content: it increased up to 15 wt% silica but then decreased with further increase in silica content. However, the particle size was only marginally influenced by the silica content. The zeta potential of the composite particles slightly decreased with increasing silica content. With increasing VA-057 concentration, the PS microspheres were entirely coated with silica sol above 1.0 wt% initiator.

• The Korean Journal of Food And Nutrition
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• v.36 no.3
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• pp.172-184
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• 2023

The objective of this study was to determine the efficacy of a natural product of cherry tree (Prunus serrulata var. spontanea: PS) as a test substance for improving cytokine and ovalbumin-specific IgE using an ovalbumin-induced asthma disease model of 5-week-old male BALB/c mice. Lung tissue pathology was analyzed to confirm anti-inflammatory and asthmatic effects. As a result of examining the effect on changes in inflammatory cells in bronchoalveolar lavage fluid in an ovalbumin-induced asthma disease model by administering the PS sample, total cells, eosinophil, neutrophil, lymphocyte, and monocytes were significantly decreased. Concentrations of cytokine-based TNF-alpha and IL-4 and immunoglobulin E in serum were significantly increased in the asthma-inducing negative control group than in the normal group. However, high concentrations of PS decreased them. In histopathological examination of the lung tissue, it was confirmed that inflammatory cells infiltrated around the alveoli and bronchioles were increased in ovalbumin-induced asthma disease model. After administration of cherry tree extract, bronchiolar morphological changes such as mucosal thickening were slightly improved. From the above results, it was confirmed that extract of cherry tree significantly reduced inflammation expression and tissue damage in alveolar tissues. It was also confirmed that the cherry tree extract had an excellent efficacy in improving asthma inflammation.

• Journal of Information Technology Services
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• v.22 no.5
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• pp.17-30
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• 2023

A company's sustainable growth is a very important goal, and for this purpose, the company's business model is changing into a convergence of products and services. The purpose of PS-Offering is to maintain a long-term relationship with customers, and customer experience management is necessary for this. This study presents a service design methodology that can support customer experience management of the PS-Offering business model. The experience management portfolio analysis methodology consists of four steps: 1. Deriving service encounter through customer journey maps; 2. Identify the service structure of each service encounter in three forms (FFC, FSC, FSE). 3. Analyze the customer's emotional variables, that is, customer experience, at each service encounter, Finally, 4. After plotting the level of customer experience at the service encounter, the analysis is conducted with a customer experience management portfolio that seeks future strategic plans for this. The methodology presented in this study will help in the service design of the service encounter unit centered on customer experience. And it will improve the financial performance of the company by raising the service level of the business model.

• Journal of Chest Surgery
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• v.20 no.4
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• pp.688-694
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• 1987

At the Dept. of Thoracic and Cardiovascular Surgery of Pusan National University Hospital, postoperative cardiac catheterizations were performed in 12 patients of ventricular septal defect with severe pulmonary hypertension [Pp/Ps>0.75], who were operated during the period from July 1981 to Dec. 1986. The mean age of the patients preoperatively was 12.4 [range: 4-18] year-old and the mean follow-up duration was 25.8 [range: 8-53] month per patient. In comparison with the preoperative data, the systolic pulmonary artery pressure [SPAP] was decreased from 103.6*18.4 to 70.4*35.9 mmHg [p<0.01] and the Pp/Ps was decreased from 0.89*0.10 to 0.58*0.27 [p<0.01]. But the Rp/Rs and Rp were not meaningfully changed, from 0.31*0.16 and 7.6*0.4 unit to 0.41*0.32 and 8.0*6.6 unit, respectively. The preoperative Qp/Qs was bellow 2.0[mean: 1.6] in 3 out of 4 cases whose postoperative Rp/Rs and Rp were above 0.75 and 15 unit, respectively. On the contrary, the preoperative Qp/Qs was above 2.0 [mean: 3.5] in all of the 8 cases, whose postoperative Rp/Rs and Rp were below 0.50 and 10 unit, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.10
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• pp.1325-1332
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• 2010

This study was conducted to evaluate the effects of the particle size (PS) of alfalfa hay (AH) and soybean hull (SH) on milk production of dairy cows and the population of major cellulolytic bacteria in the rumen. Eight lactating Holstein cows, averaging $590{\pm}33\;kg$ BW and $47{\pm}13$ days in milk (DIM), were assigned in a $4{\times}4$ Latin square design to a $2{\times}2$ factorial arrangement of treatments: alfalfa hay particle size (fine vs. coarse) combined with soy hull (zero or substituted as 50% of AH). The cows were fed diets formulated according to NRC (2001). Physically effective factor (pef) and physically effective fiber (peNDF) contents of diets increased by increasing AH particle size and inclusion of SH in the diets (p<0.01). Dry matter intake was not significantly affected by treatments but intake of peNDF was increased marginally by increasing the PS of AH (p = 0.08) and by SH inclusion (p<0.01) in the diets. Milk production was increased by feeding diets containing SH (p = 0.04), but it was not affected by the dietary PS. Milk fat content was increased by increasing AH particle size (p = 0.03) and decreased by SH substitution for a portion of AH (p<0.01). The numbers of total bacteria and cellulolytic species were not affected by PS of AH or by SH. F. succinogenes was the most abundant species in the rumen followed by R. albus and R. flavefaciens (p<0.01). This study showed that SH cannot replace the physically effective fiber in AH having either coarse or fine particle size. In diets containing SH, increasing of diet PS using coarse AH can maintain milk fat content similar to diets without SH. Particle size and peNDF content of diets did not affect the number of total or fibrolytic bacteria in the rumen.

• Korean Journal of Food Science and Technology
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• v.43 no.4
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• pp.513-517
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• 2011

The effects of nonthermal plasma treatments against Salmonella Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes living on polystyrene (PS), sausage casings, and smoked salmon were investigated. Inoculated PS, casings, and salmon were treated with nonthermal plasma generated with helium (5 L/min) or with both helium (5 L/min) and oxygen (100 mL/min) at 60 Hz and 30 kV/cm for 2, 5, or 10 min. S. Typhimurium exhibited the highest sensitivity to the helium-used treatment. The greatest reduction (3.9${\pm}$0.8 log$CFU/cm^2$) was observed with L. monocytogenes on PS after the treatment with the mixed gas for 5 min. The treatment with the mixed gas inhibited L. monocytogenes on casings and salmon by 0.5${\pm}$0.3 log$CFU/cm^2$ and 1.0${\pm}$0.3 log CFU/g, respectively. Different treatment times did not result in different reductions of L. monocytogenes on both casings and salmon. The types of treatment gas and material of contamination need to be considered for evaluating the antimicrobial effects of nonthermal plasma treatments.

• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.676-685
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• 2016

This study investigated the conversion of oil products from polystyrene by using dispersed Co and Mo catalyst on reaction time and concentration change for knowledging on characteristics at low temperature (425, 450 and $475^{\circ}C$) pyrolysis and reaction time(20~80 min, 15 min interval) in a batch reactor. It will be showed the conditions for optimum pyrolysis at reaction temperature $450^{\circ}C$ and the reaction time 35min, and the main components of the converted liquid oil were styrene and benzene derivatives by GC/MS. The oil products formed during pyrolysis were classified into gas, gasoline, kero, diesel and heavy oil according to the domestic specification of petroleum products. The pyrolysis conversion rate was showed as Co catalyst > Mo catalyst > Thermal in all reaction time at reaction temperature $450^{\circ}C$. The yields rate of gas, kerosine, diesel were the most hight at Mo Catalyst, gasoline was at thermal and heavy oil was at Co catalyst. The conversion rate and yields of the pyrolysis products were the most height when Co catalyst ratio was 100%.

• Journal of the Korea Society of Computer and Information
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• v.28 no.10
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• pp.133-153
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• 2023

In this paper, we propose a novel approach to investigating brain-signal measurement technology using Electroencephalography (EEG). Traditionally, researchers have combined EEG signals with bio-signals (BSs) to enhance the classification performance of emotional states. Our objective was to explore the synergistic effects of coupling EEG and BSs, and determine whether the combination of EEG+BS improves the classification accuracy of emotional states compared to using EEG alone or combining EEG with pseudo-random signals (PS) generated arbitrarily by random generators. Employing four feature extraction methods, we examined four combinations: EEG alone, EG+BS, EEG+BS+PS, and EEG+PS, utilizing data from two widely-used open datasets. Emotional states (task versus rest states) were classified using Support Vector Machine (SVM) and Long Short-Term Memory (LSTM) classifiers. Our results revealed that when using the highest accuracy SVM-FFT, the average error rates of EEG+BS were 4.7% and 6.5% higher than those of EEG+PS and EEG alone, respectively. We also conducted a thorough analysis of EEG+BS by combining numerous PSs. The error rate of EEG+BS+PS displayed a V-shaped curve, initially decreasing due to the deep double descent phenomenon, followed by an increase attributed to the curse of dimensionality. Consequently, our findings suggest that the combination of EEG+BS may not always yield promising classification performance.

• Journal of Mushroom
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• v.22 no.1
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• pp.31-36
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• 2024

Plastics are widely used in industries in human society and because of their structural stability, degradation is a serious global issue. To estimate the degradation of plastic, 31 edible mushrooms were cultured with the selected plastic films (polyethylene [PE], polystyrene [PS], and poly(ethylene terephthalate) [PET]) for 3 months at 25 ℃. Measuring the weight of the films showed that four species of mushrooms, namely Porostereum spadiceum, Ganoderma lucidum, Coprinellus micaceus, and Pleurotus ostreatus, exhibited the highest degrees of plastic degradation. In addition, the mushrooms and fungi that exhibited the most significant plastic degradation were cross-cultured to promote this degradation. As a result, cross-cultivation of G. lucidum and Aspergillus niger showed a weight loss of 2.49% for the PET film. For the PS film, Aspergillus nidulans showed a weight loss of 4.06%. Cross-cultivation of A. nidulans and C. micaceus, which showed a weight loss of 2.95%, was noted as an alternative for PS biodegradation, but is harmful to humans. These bio-degradation effects of edible mushroom will contribute to the development of alternatives for eco-friendly plastic degradation.