• Journal of Food Hygiene and Safety
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• v.33 no.2
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• pp.102-109
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• 2018

In the present study, a variety of polylactide (PLA) articles (n = 211) were tested for migration of lead (Pb), cadmium (Cd) and arsenic (As) into the food simulant (4% v/v acetic acid). Pb, Cd, and As were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Migration tests were performed at $70^{\circ}C$ and $100^{\circ}C$ for 30 min. The amounts of Pb, Cd, and As increased at $100^{\circ}C$ for 30 min compared with levels at $70^{\circ}C$. However, the migration at both conditions was very low. The maximum level of Pb at $100^{\circ}C$ for 30 min corresponded to 1% of the migration limit. The estimated daily intakes (EDI) based on safety evaluation ranged from $2.5{\times}10^{-5}$ to $2.0{\times}10^{-3}{\mu}g/kg\;bw/day$ for Pb, Cd, and As. The EDI calculated from migration of Pb at $100^{\circ}C$ for 30 min in PLA was the maximum value, $2.0{\times}10^{-3}{\mu}g/kg\;bw/day$, which corresponded to 0.055% of provisional tolerable weekly intake (PTWI, $25{\mu}g/kg\;bw/week$). The data from this study represent a valuable source for science-based safety control and management of hazardous heavy metals migrating from polylactide food contact materials.

• Analytical Science and Technology
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• v.5 no.2
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• pp.199-202
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• 1992

Ti-silicide was formed by using metal-Ti target and composite target on the silicon substrate that $BF_2$ were introduced into. Implant energies of $BF_2$ were 50keV and 90keV. The behavior of boron was investigated by SIMS. The redistribution of boron occurred during the formation of Ti-silicide by metal-Ti target and the sample implanted at the energy of 50keV showed severe out-diffusion. In the case that Ti-silicide was formed by composite target, there was little redistribution of boron.

• Resources Recycling
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• v.21 no.1
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• pp.60-65
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• 2012

The Ti-6Al-4V alloys were prepared by recycling of dental Ti pure scraps using vacuum arc melting process, and their physical properties were evaluated the Ti-6Al-4V alloys with different oxygen concentrations. For the preparation of Ti-6Al-4V alloys, Ti pure scraps used for dental implant were utilized as a raw material, and their different oxygen concentrations were ranged from G1 to G4 grade in ASTM standards. It was confirmed that the weight loss of Al in the composition of Ti-6Al-4V alloy could be controlled under the Ar pressure of 875 torr during the melting of alloy. The oxygen concentrations of the Ti-6Al-4V alloys were ranged from 1170 to 3340 ppm. The vickers hardness change of the Ti-6Al-4V alloys showed a similar behavior with that of pure Ti. As a result, we confirmed a possibility of preparation of Ti-6Al-4V alloy by recycling of dental Ti scraps using vacuum arc melting process in this study.

• Clean Technology
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• v.14 no.3
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• pp.204-210
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• 2008

A series of $V_{2}O_{5}-TiO_2$ xerogel catalysts were prepared by nonhydrolytic sol-gel method and analysed by various characterization techniques. These catalysts showed much higher surface areas and total pore volumes than conventional V$V_{2}O_{5}-TiO_2$ xerogel and impregnated $V_{2}O_{5}/TiO_2$ catalysts. It was found that the textural property of $V_{2}O_{5}-TiO_2$ material varies with the method and conditions of synthesis. Surface vanadates and $TiO_2$ anatase phase are the crucial factors to obtain high catalytic activities. The selective oxidation of hydrogen sulfide in the presence of excess water and ammonia was studied over these catalysts. Xerogel catalysts prepared by non-hydrolytic sol-gel method showed very high conversion of $H_{2}S$ without harmful emission of $SO_2$. The highest catalytic activity shown by these $V_{2}O_{5}-TiO_2$ catalysts may be due to their high surface area and good dispersion of vanadia species in the titania matrix.

• Journal of muscle and joint health
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• v.17 no.1
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• pp.58-67
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• 2010

Purpose: The purpose of this study was to examine the effect of the Tai chi exercise program on the physical function, self-esteem and social behavior in patients with chronic schizophrenia. Methods: This study utilized a nonequivalent control group with pretest-posttest design. The 45 subjects were recruited from a mental health care facility in D city and randomly assigned either to the experimental group (n=23) or to the control group (n=22). The experimental group participated in the Tai chi exercise program, twice a week for 12 weeks. Data were analyzed with SPSSWIN V. 11.5 program, using $X^2$-test and t-test. Results: After 12 weeks, there were significant differences in flexibility (p=.027), balance (p=.011), self-esteem (p=.005) and social behavior (p=.003) between the experimental and the control groups. Conclusion: The findings of this study revealed the positive effects of Tai-Chi exercise program in patients with schizophrenia. Further studies are required to determine the effects on physical and social variables.

• Korean Journal of Food Science and Technology
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• v.17 no.4
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• pp.276-282
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• 1985

To characterize bitter peptides in fermented protein foods, peptides were extracted with 2:1 (v/v) chloroform-methand from various samples and separated into fractions I, II, and III by Sephadex G-25 gel chromatography. Amino acid compositions of Mozzarella cheese, soybean paste, and each fraction from the two samples were analyzed to calculate the average hydrophobicity. All the solvent extracts of the food samples had strong bitter taste, although the original samples did not taste bitter. The yield of solvent extraction ranged from 0.08 to 62.50% of total nigrogen of food samples. The average hydrophobicity calculated from the amino acid composition of Mozzarella cheese was 1376 cal/mole, solvent extract 1,623 cal/mole, gel chromatography traction I, 1,797 cal/mole, fraction II, 2,454 cal/mole, and fraction III, 1,559 cal/mole. In the case of soybean paste, the average hydrophobicity of original sample, solvent extract, gel chromatography fraction I, II, and III wre 1,229, 1,654, 1,900,998 cal/mole, respectively. The important amino acids in bitter peptides were leucine, 2016, phenylalanine, proline, and voline.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.34-36
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• 1996

For the test of the operating characteristics as a moor, a 20 kVA super conducting synchronous machine with rotating field windings has been made in Saga university, Japan from 1991. Before the load tests of it as a motor, we carried out cooling down tests and measured its machine constants. During the cooling down tests, we found that the rotor itself had no cryogenic problem, but the inlet part for liquid He had one. Though enough liquid He couldn't be accumulated inside the rotor because of this problem, we drove field currents up to 20 A and could acquire the machine constants and V curves of the super-conducting synchronous motor.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.31-32
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• 2012

능동클램프 타입의 전류원 컨버터는 입력전류 리플이 작으며 클램프로 서지제거는 물론 스위치의 ZVS 턴온을 가능하게 한다. 그 중 부스트 하프브리지 컨버터는 변압기 턴비와 다이오드 정격이 낮고 모든 소자가 대칭적 구조를 가지며 변압기의 마그네타이징 오프셋이 없으므로 연료전지와 같은 대전류 고승압 응용에 적합하다. 본 논문에서는 준공진 기법을 적용하여 스위치 턴오프 전류를 크게 감소시킨 능동클램프 타입의 부스트 하프브리지 컨버터를 제안한다. 16V, 1.2kW급 시작품으로 기존 방식과의 비교분석을 통하여 제안하는 방식의 타당성을 입증하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.831-834
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• 2000

Characteristics of organic light-emitting diodes(OLEDs) were studied with devices made by PECCP[poly(3,6-N-2-ethylhexyl carbazolyl cyanoterephthalidene)] Langmuir-Blodget(LB) films. The emissive organic material was synthesized and named PECCP, which has a strong electron donor group and an electron accepter group in main chain repeated unit. The LB technique was employed to investigate the identification of the recombination zone in the ITO/PECCP LB films/Alq$_3$/Al structure by varying the LB film thickness. PECCP was considered as an emissive layer and Alq$_3$was used as an electron-transport layer. We measured current-voltage(I-V) characteristics, UV/visible absorption, PL spectrum, and EL spectrum of those devises.

• Journal of Periodontal and Implant Science
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• v.28 no.4
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• pp.659-678
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• 1998

In the present study, oligonucleotide probes based on 16S rRNA were taken to investigate the diversity of oral spirochetes without culture method. This is the first study that revealed oral spirochetes of both presently cultivable and uncultured oral spirochetes in Korean adult periodontitis patients. Subgingival plaque samples were taken from diseased sites(probing depth ${\geq}6\;mm$, experimental group, n=116) and healthy sites(probing depth${\leq}3mm$, control 1 group, n=28) in 29 patients with adult periodontitis, and from 20 periodontally healthy subjects(probing depth${\leq}3mm$, control 2 group, n=100). Following being examined under phase-contrast microscope, all samples were submitted to dot-blot hybridization after polymerase chain reacton with eubacterial primers. 5 species-specific probes(TVIN, TDEN, TMAL, TSOC, and TPEC) and 7 group-specific probes(TRE I, TRE II, TRE III, TRE IV, TRE V, TRE VI, and TRE VII) were used one by one for the identification of both cultivable and so far uncultivable oral spirochetes. All probes were labeled with digoxigenin(DIG)-ddUTP and detected by chemilumininescence. The following results were obtained. 1. Under phase-contrast microscope, 91.37% and 14.28% of oral spirochetes were observed in the experimental and control 1 groups, respectively. None of oral spirochetes were observed in control 2 group. 2. With universal probe, 98.27%, 46.42%, and 22.0% of oral spirochetes were observed in experimental, control 1, and control 2 groups, respectively. 3. With specific probe, 95.68%, 35.71%, and 19.0% of oral spirochetes were observed in experimental, control 1, and control 2 groups, respectively. 4. With species-specific probes, T. socranskii were recovered in a high percentage of sites(81.89%) examined, followed by T. maltophilum(50.0%), T. vincentii(36.20%), T. denticola(13.79%), respectively. With group- specific probes, TRE IV was recovered in a high percentage of sites(85.34%) examined, followed by TRE II(77.58%), TRE I(56.89%), TRE III(25.86%), TRE VI(5.17%), and TRE V(2.58%), respectively. 5. T. vincentii were only observed in the diseased sites, not in the healthy sites. 6. Neither T. pectinovorum nor group VII oral spirochetes were observed in any sites. The findings warrant further investgations of the recovered spirochetes to elucidate the possible associations of oral spirochetal prevalence in race and types of periodontitis, pathogenesis of T. vincentii and the possible distributional change of oral spirochetes before and after treatments.