• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.15-22
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• 1999

Polymeric meterials that are used for noise and vibration damper in wood/polymer/wood sandwich composites, must have a high loss factor(tan ${\delta}$), and at the same time the storage modulus(E) of $5{\times}10^7$ to $10^9$ dyne/$cm^2$ must withstand over a wide temperature and frequency ranges. In this study, the series of epoxy resinlpolyacrylate interpenetrating polymer networks(IPNs) were synthesized by simultaneous polymerization. Their dynamic tensile properties were measured at 110Hz using Rheovibron instrument. Composite damping factor(tan ${\delta}_c$) and dynamic bending modulus($E_c,\;E_^{\prime\prime}c$) of wood/polymer/wood sandwich composites were measured at 110Hz using a Rheovibron in bending mode of vibration. These dynamic tensile studies indicated that cured epoxy resin/polyacrylates IPNs were semicompatible in the sense that both the shifting of T($E^{\prime\prime}_{max}$) or T(tan ${\delta}_{max}$) and the broadening of glass transition temperature range were observed. Especially, the cured Epikote871/P(n-BMA) IPNs of composition 70/30 to 50/50 showed a relatively high tan a and appropriate E' value over a wide temperature range; consequently the tan a e curves of wood/IPNs/wood sandwich composites was broadened over a wide temperature range.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.2
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• pp.99-107
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• 2006

Magnetic nondestructive testing is very useful far detecting a crack on the surface or near of the surface of the ferromagnetic materials. The distribution of the magnetic flux leakage (DMFL) on a specimen has to be obtained quantitatively to evaluate the crack. The magnetic camera is proposed to obtain the DMFL at the large lift-off. The magnetic camera consists of a magnetic source, magnetic lens, analog to digital converters (ADCs), interface, and computer. The magnetic leakage fields or the distorted magnetic fields from the object, which are concentrated on the magnetic lens, are converted to analog electrical signals tv arrayed small magnetic sensors. These analog signals are converted to digital signals by the ADCs, and are stored, imaged, and processed by the interface and computer. However the magnetic camera has limitations with respect to converting and switching speed, full range and resolution, direct memory access (DMA), temporary storage speed and volume because common ADCs were used. Improved techniques, such as those that introduce the operational amplifier (OP-Amp), amplify the signal, reduce the connection line, and use the low pass filter (LPF) to increase the signal to noise ratio are necessary. This paper proposes the exclusive embedded ADC including OP-Amp, LPF, microprocessor and DMA circuit for the magnetic camera to satisfy the conditions mentioned above.

• Korean Journal of Food Science and Technology
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• v.40 no.6
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• pp.669-673
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• 2008

For the development of a biological control method against B. cereus in cheonggukjang, 20 Bacillus spp. were isolated from the naturally fermented baektae and heuktae cheonggukjang, identified by using 16S rDNA sequences. Among the isolated strains, Bacillus sp. SC-8 was selected using the B. cereus lawn cell assay as an antagonistic microorganism against B. cereus. The culture medium of Bacillus sp. SC-8 after 24 hr of incubation at $37^{\circ}C$ also evidenced a high level of antagonistic activity. In cheonggukjang fermented with the mixed culture of Bacillus sp. SC-8 and B. cereus, antagonistic effect against B. cereus was maintained during the fermentation of cheonggukjang, while its effect was reduced during storage at $4^{\circ}C$ due to the decrement of cell population of Bacillus sp. SC-8. In Bacillus sp. SC-15, which was utilized a control, antagonistic activity against B. cereus was not demonstrated on the lawn cell plate assay and culture medium, but its effects were detected in cheonggukjang. Therefore, the production of antagonistic substances of Bacillus spp. depends on the fermentative environment.

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.390-397
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• 2010

Residual solvents in foods are defined as organic volatile chemicals used or produced in manufacturing of extracts or additives, or functional foods. The solvents are not completely eliminated by practical manufacturing techniques and they also may become contaminated by solvents from packing, transportation or storage in warehouses. Because residual solvents have no nutritional value but may be hazardous to human health, there is a need to remove them from the final products or reduce their amounts to below acceptable levels. The purpose of this study was to develop and evaluate an analytical method for the screening of residual solvents in health functional foods. Furthermore, the aim of this study was to constitute a reasonable management system based on the current state of the market and case studies of foreign countries. Eleven volatile solvents such as MeOH, EtOH, trichloroethylene and hexane were separated depending on their column properties, temp. and time using Gas Chromatography (GC). After determining the GC conditions, a sample preparation method using HSS (Head Space Sampling) was developed. From the results, a method for analyzing residual solvents in health functional foods was developed considering matrix effect and interference from the sample obtained from the solution of solvents-free health functional foods spiked with 11 standards solutions. Validation test using the developed GC/HSS/MS (Mass Spectrometry) method was followed by tests for precision, accuracy, recovery, linearity and adequate sensitivity. Finally, examination of 104 samples grouped in suits was performed by the developed HSS/GC/MS for screening the solvents. The 11 solvents were isolated from health functional foods based on vapor pressure difference, and followed by separation within 15 minutes in a single run. The limt of detection (LOD), limit of quantification (LOQ), recovery and coefficient of variation (C.V.) of these compounds determined by the HSS/GC/MS were found to be 0.1 pg/mL, 0.1-125 pg/g, 51.0-104.6%, and less than 15%, respectively. Using the developed HSS/GC/MS method, residual solvent from 16 out of 104 health functional products were detected as a EtOH. This method therefore seems t o be a valuable extension ofanalytical method for the identification of residual solvents in health functional food.

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.325-332
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• 2013

We aimed to determine the quality indicators for quality prediction of frozen green pumpkin in distribution. Freshly harvested green pumpkin slices were blanched under optimal conditions (confirmed in a preliminary experiment), quick-frozen at $-40^{\circ}C$ for 24 h, and stored at 0, -5, -15, and $-25^{\circ}C$. The correlation between each quality characteristic and the sensory preference rate was analyzed. There was a significant correlation between storage temperature-related drip rate and preference rate across all temperatures, except at$-25^{\circ}C$. Hunter values, a and b, showed relatively high correlation coefficient values at -5, -15, and $-25^{\circ}C$. Therefore, a change in the Hunter values should be considered when storing green pumpkin, because of their significant correlation with changes in the sensory preference and drip rates. Furthermore, they should be applied as quality indicators for the quality prediction of frozen green pumpkin in distribution.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.726-731
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• 2013

Experiments were conducted to evaluate the effect of low temperature-darkness treatment on floral initiation in four kinds of Korean strawberry cultivars. Mother plants were planted on March 29 and daughter plants were raised for the experiment. Temperature treatment was done for 7, 14, and 21 days keeping $13^{\circ}C$ in cooling storage from August 29, September 5 and September 14 to September 21. After the treatment, flower bud initiation was examined by a microscope, and the seedlings were transplanted on hydroponic system with Yamazaki's strawberry solution of EC $0.8dS{\cdot}m^{-1}$ to check the flowering. 'Ssanta' and 'Maehyang' showed early flower bud initiation in 7 days treatment than 'Seolhyang' by microscope check. 'Ssanta', 'Daewang', and 'Maehyang' showed early flower bud initiation in 14 days treatment than 'Seolhyang'. There were no differences among the treatments in 21 days treatment. Percentage of flowering of 'Seolhyang' and 'Maehyang' by low temperature-darkness treatment didn't show any difference but 'Daewang' and 'Ssanta' showed high percentage of flowering. It suggested that low temperature-darkness treatment technique can be use for improving early flowering and yield of 'Ssanta' and 'Daewang' cultivars.

• Journal of Internet Computing and Services
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• v.9 no.6
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• pp.1-13
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• 2008

Trusted Computing is a hardware-based technology that aims to guarantee security for machines beyond their users' control by providing security on computing hardware and software. TPM(Trusted Platform Module), the trusted platform specified by the Trusted Computing Group, acts as the roots for the trusted data storage and the trusted reporting of platform configuration. Data sealing encrypts secret data with a key and the platform's configuration at the time of encryption. In contrast to the traditional data sealing based on binary hash values of the platform configuration, a new approach called property-based data sealing was recently suggested. In this paper, we propose and analyze a new property-based data sealing protocol using the weakest precondition concept by Dijkstra. The proposed protocol resolves the problem of system updates by allowing sealed data to be unsealed at any configuration providing the required property. It assumes practically implementable trusted third parties only and protects platform's privacy when communicating. We demonstrate the proposed protocol's operability with any TPM chip by implementing and running the protocol on a software TPM emulator by Strasser. The proposed scheme can be deployed in PDAs and smart phones over wireless mobile networks as well as desktop PCs.

• Journal of Life Science
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• v.25 no.1
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• pp.16-20
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• 2015

During the storage of these two species in a large conservation tank, fertilized eggs were collected and the offspring were raised. During culturing of the offspring, individuals with mixed characteristics of these two species were observed, and 96 individuals were randomly tested using microsatellite markers applicable to both species. Among the 96 individuals, 15 individuals with mixed morphological characteristics were confirmed to be hybrids showing both of genotypes red seabream and blackhead seabream. Additionally, based on sequence analysis of mitochondrial cytochrome oxidase subunit 1 (mtDNA CO1), 81 showed 99% nucleotide sequence identity to that of black sea bream, and the remaining 15 individuals showed over 99% sequence identity to that of red seabream. So, hybrids were produced by female red seabream and male blackhead seabream. These results suggest that hybrids may form in nature between these two species if their habitats overlap due to the influence of humans or global climate change.

• Journal of Life Science
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• v.26 no.12
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• pp.1438-1445
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• 2016

Yeast can be post-contaminated by the equipment, producer, or air, and this can degrade yogurt quality. This study aimed to demonstrate the yeast inhibiting effect in fermented milk by adding Lactobacillus paracasei and Lactobacillus rhamnosus along with current fermenting lactic acid bacteria such as Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. A certain amount of yeast was added to fermented milk samples that were soon after stored at variable temperatures, and the number of yeast cells was counted periodically. The swelling phenomenon caused by the gas produced by the yeast in fermented products was also observed. In the two experiments, compared to the control, the L. paracasei- and L. rhamnosus-added-groups showed much slower rate of yeast appearance and lower frequency of swelling phenomena. This suggests that using a mixture of L. paracasei and L. rhamnosus in fermented milk inhibits the growth of yeast. Furthermore, if the products are stored at $10^{\circ}C$, post-acidification is rarely seen in the experimental group compared to the control group. This means that the organoleptic flavor can be kept consistent from the production day till the expiration day, resulting in improved organoleptic quality for customers. In other words, the use of L. paracasei and L. rhamnosus in fermented milk will result in the following positive effects: improvement in storage stability by delaying yeast appearance, increase in quality consistency by inhibiting post-acidification, and improved organoleptic quality by enhancing texture and flavor.

• Journal of Life Science
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• v.29 no.12
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• pp.1364-1370
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• 2019

The anti-oxidant activity, sinigrin content, and sensory evaluation of frying batter treated with Dolsan leaf mustard powder (DLMP) were investigated. These endpoints were measured in the control sample (batter without DLMP) and seven other batters with the addition of DLMP in the following quantities: 0.03 g (S-1), 0.02 g (S-2), 0.06 g (S-3), and 0.3 g (S-4, S-5, S-6, and S-7 with different amounts of red pepper powder). The acid value (AV) and peroxide value (POV) were low in the S-4 and S-5 batters; the total polyphenol content was 190.97 mg GAE/g in the control sample and 721.17 mg GAE/g in S-4; and the total flavonoid content of S-6 was 67.82 mg QE/g which was higher than that of the control sample. The anti-oxidant activity was measured by EDA, ABTS, and FRAP assays and was seen to rise as the amount of DLMP increased. Moreover, sinigrin content was higher in S-4, S-5, S-6, and S-7 than in the control, S-1, S-2, and S-3, and there were no significant differences among S-4 to S-7 when just 0.3 g of DLMP was added. Sensory evaluation showed that color, flavor, taste, texture, and overall acceptability values were significantly higher in S-4 and S-5, and that there was no significant difference across the samples. The addition of DLMP is therefore expected to increase the anti-oxidant activity of frying batter which would be effective in improving the storage and quality of the product.