• Title/Summary/Keyword: halo test

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Observation of Shear Bonding Strength by Compositional Change and Firing Steps of the Ni-Cr Alloy for Porcelain Fused Metal Crown (금속-도재관용 Ni-Cr합금의 조성변화와 소성단계에 따른 전단결합강도)

  • Cho, Yong-Wan;Hong, Min-Ho;Kim, Won-Young;Choi, Sung-Min;Chung, In-Sung
    • Journal of Technologic Dentistry
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    • v.35 no.4
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    • pp.353-358
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    • 2013
  • Purpose: This study was observation shear bonding strength by compositional change and firing step of a Ni-Cr alloy for porcelain fused metal crown. The aim of study was to suggest the material for firing step of Ni71-Cr14 alloy to development of alloy for porcelain fused to metal crown. Methods: The test was on the two kinds of Ni-Cr alloy specimens. The surfaces of two alloys were analyzed by EDX in order to observe oxide characteristic. And the shear test was performed by MTS. Results: The surface property and oxide characteristic analysis of oxide layer, weight percentage of Element O within $Ni_{71}Cr_{14}$ alloy measured 23.32wt%, and $Ni_{59}Cr_{24}$ alloy was measured 23.03wt%. And the maximum shear bonding strength was measured 58.02MPa between $Ni_{59}Cr_{24}$ alloy and vintage halo(H4 group). Conclusion: The surface property and oxide characteristic three kind of Ni-Cr alloy was similar. and shear bonding strength showed the highest bonding strength in H4 specimens.

Characterization of Brewing Yeast Expressing Glucoamylase Selected by Rare Mating. (Rare Mating에 의한 양초효모에서의 glucoamylase 발현 균주 HCS 선별 및 특성)

  • 최병주;장금일;김광엽
    • Microbiology and Biotechnology Letters
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    • v.29 no.4
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    • pp.212-220
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    • 2001
  • Rare mating was used to select a respiratory deficient mutant of Saccharomyces cerevisiae HDC52 strain. Glucoamylase gene of S. diastaticus K114 was developed into the RD mutant which could uptake maximum amount of non-fermentable sugars through the expression of glu- coamplyase gene and the fermentation characteristics of the developed strain HCS were investigated. The size of HCS yeast and HBD52 yeast strain were 13 $\mu\textrm{m}$ and 10$\mu\textrm{m}$ respectively. HCS strain which can uptake maximum amount of non-fermentable sugar through the expression of glucoamylase gene was developed. By karyotype anal- ysis. HCS stain but not RD mutant HBC52 showed a band of 1150 kb chromosome DNA This band should include glcoamylase gene from Saccharomyces diataticus K114 THis strain has glucoamylase which can degrade starch By transduction and contrnuance of glucoamylase gene HCS strain gegraded strach and formed halo. Also, HCS strain maintained the character after 50 generations. Glucoamylase activities of Saccharomyces diastaticus K114 and HCS yeast strains are 9.5 and 2.7~3.4(unit/ml) HCS and HBC52 strain showed similar sugar fermentation patterns and low flocculation In spore and film forming test, HCS and HBC52 strain formed neither spores nor films. In the limit fermentation test, HBC52 strain showed fermentation level of 68% and HCS strain showed 76~78% As the limit attenuation of HBC52 and HCS were ($2.00^{\circ}$P) and ($0.7~0.93^{\circ}$P) This study demon- strates and HCS strain may be used for low carbohydrate beer fermentation.

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Inhibition of yeast Candida growth by protein antibiotic produced from Pseudomonas fluorescens BB2 (Pseudomonas fluorescens BB2 균주가 생산하는 단백질성 항생물질에 의한 효모 Candida 생육 억제)

  • Ahn, Kyung-Joon
    • Korean Journal of Microbiology
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    • v.51 no.4
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    • pp.448-452
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    • 2015
  • The bacterial strain that was isolated from chinese cabbage rhizosphere, showed inhibition of yeast growth. This strain was identified as Pseudomonas fluorescens BB2 by API 20NE test and 16S rRNA gene sequence analysis. P. fluorescens BB2 strain produced antibiotics against yeast as a secondary metabolite effectively when the culture was carried out in YM medium with 3% glucose at $20^{\circ}C$. The protein antibiotic of BB2 strain which was concentrated by ammonium sulfate precipitation and n-butanol extraction inhibited the growth of yeast with the minimal inhibitory concentration of $10{\mu}g/ml$ against Candida albicans KCTC 7965, and the growth of yeast was completely inhibited at $80{\mu}g/ml$. The hydrophilic fraction of n-butanol extraction inhibited the growth of Bacillus cereus ATCC 21366, showed orange halo on chrome azurol S plate, which means the fraction contained iron chelating siderophore. The results of crystal violet uptake through the cell membrane showed that membrane permeability was increased about 9% than control, when the concentration of hydrophobic antibiotic against yeast C. albicans was $60{\mu}g/ml$. As a result, the antibiotic produced by P. fluorescens BB2 against yeast Candida is considered antimicrobial peptide, and this is the first report in the genus Pseudomonas.

Corrosion Characteristics of a 5Cr-1Mo Steel Specimen by Sodium-Water Reaction (나트륨-물 반응에 의한 5Cr-1Mo Steel 시편의 부식특성)

  • Jeong, Kyung-Chai;Jeong, Ji-Yeong;Park, Jin-Ho;Hwang, Sung-Tai;Kim, Eui-Sik
    • Applied Chemistry for Engineering
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    • v.9 no.7
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    • pp.1023-1029
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    • 1998
  • Small water leak experiment was carried out for the 5Cr-1Mo steel specimen in sodium atmosphere. Perfect re-open time for the leak path of a specimen, by micro leak, was 129 minutes, and its size observed about 2 mm diameter at sodium side. The halos phenomena appeared around of leak spot before the leak path has re-opened, and the size of halos observed was different from the real re-open size of a specimen. Also, the corrosion of a specimen initiated from sodium side, but it did not occur at steam side. In AES analysis, the segregation phenomena of Cr in the specimen was found much more than those of other elements. And also, the sodium compounds formed by sodium-water reaction and deposited onto the leak site of specimen were observed by EPMA analysis and SEM photograph. It is postulated that the corrosion products could be precipitated to form mixed Na Fe Cr compounds.

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A study on preference of Baekje culture relics and purchasing behaviors of fashion cultural products of adolescents (청소년의 백제문화 유물에 대한 선호도와 패션문화상품 구매행동 연구)

  • Lee, Mi-sook
    • Journal of the Korea Fashion and Costume Design Association
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    • v.20 no.4
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    • pp.41-56
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    • 2018
  • The purposes of this study were to investigate preference of Baekje culture relics and to examine purchasing behaviors of fashion cultural products of adolescents. The subjects were 421 adolescents and measuring instruments consisted of Baekje relics preference items, fashion cultural products purchasing behaviors items, and subject' demographic attributions. The data were analyzed by frequency analysis, $x^2$ test, factor analysis, t-test, ANOVA and Duncan's multiple range test using SPSS program. The results were as follows. First, adolescents were more likely to prefer crown ornaments of the King Muryong in Kongju region, and gilt-bronze incense burner and halo in Buyeo region. Second, as fashion cultural products, adolescents were more likely to prefer T-shirts and accessory items, and modern image. As product selection criteria, they considered aesthetics as the most important factor, followed by symbolism and practicality. Adolescents evaluated the resonable purchase price of fashion cultural products as less than 20,000 won for T-shirts, cap & bag, and less than 10,000 won for accessories. The adolescent's satisfaction of fashion cultural products was low, and the main dissatisfaction was high prices, and the lack of practicality and diversity. Third, the preference for Baekje cultural relics and purchasing behaviors of fashion cultural products differed according to age and sex of adolescents. This study showed that fashion culture products for adolescents need to be designed in a modern sense with a unique cultural symbolism, focusing on T-shirts and accessories items. In addition, fashion cultural products companies should established the product development plan considering the characteristics according to the age and sex of adolescents.

A Study on Improving Shock Absorption Test of Safety Helmet (안전모의 충격 흡수성 시험 개선에 관한 연구)

  • Sang Woo Shim;Yong Su Sim;Jong Bin Lee;Seong Rok Chang
    • Journal of the Korean Society of Safety
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    • v.38 no.5
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    • pp.36-42
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    • 2023
  • In this study, 50 ABE-type hard hats were procured from five certified commercial manufacturers, and shock absorption tests were conducted in accordance with Protective Equipment Safety Certification Notice No. 2020-35. The tests were performed under both high- and low-temperature conditions, adhering to safety helmet testing standards. The highest shock transmission ranges were recorded in the tests, with an average energy range of 2,600-4,108 N at high temperatures and 2,316-3,991 N at low temperatures. All five hard hat models demonstrated a maximum transmitted impact force below 4,450 N, without any loss of cap and attachment functionality, confirming their compliance with performance standards. Furthermore, we evaluated the side impact performance of the safety helmets of each company, with an average range of 4,722-5,267 N. Company A exhibited the lowest measurement at 4,722 N. Comparing these results with international safety standards and the national shock absorption test criteria, it was observed that the maximum transmitted shock value using government-specified impact weight falls within the range of 4,450-5,000 N. However, it was noted that developed countries have established specific standards for the side impact forces on safety helmets, which are legally mandated. Consequently, it is imperative for South Korea to enhance its safety helmet side impact performance test methodology to align with domestic standards in the future.

A Study of Antibacterial Paper Packaging Material Coated with Chitosan-Ag Nanocomposite Prepared by Green Synthesis (키토산-은나노 녹색합성 복합물질을 적용한 항균 기능성 포장지 연구)

  • Kyung, Gyusun;Ko, Seonghyuk
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.46 no.2
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    • pp.8-15
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    • 2014
  • A novel antibacterial paper coated with chitosan-based silver (Ag) nanocomposite prepared by green synthesis has been investigated for a wide range of application in food, agricultural and medical packaging. Green synthesis of Ag nanoparticles (AgNPs) was carried out by a chemical reaction involving a mixture of chitosan-silver nitrate (AgNO3) in an autoclave at 15 psi, $121^{\circ}C$, for 15-120 sec. AgNPs and their formation in chitosan were confirmed by both UV-Vis spectroscopy and transmission electron microscope (TEM). Fourier transform infrared spectroscopy (FTIR) study showed that free amino groups in chitosan act as an effective reductant and AgNPs stabilizer. Antibacterial test of coated paper with as-prepared chitosan-AgNPs was performed qualitatively against E. coli based on the formation of halo zones around coated papers and it was shown to be effective in suppressing the growth of E. coli with increasing Ag contents in coating layer.

First Report of Pyrenophora tritici-repentis in Wheat (Triticum aestivum L.) in Korea and in vitro Selection of an Effective Fungicide

  • Min-Hye Jeong;Eu Ddeum Choi;Seol-Hwa Jang;Sang-Min Kim;Sook-Young Park
    • The Korean Journal of Mycology
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    • v.51 no.4
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    • pp.277-286
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    • 2023
  • Tan spot, caused by Pyrenophora tritici-repentis, is a major foliar disease in wheat worldwide. In April 2021, tan spot symptoms were observed in a commercial wheat field in Suncheon, Jeonnam Province, Korea, with over 5% of the wheat leaves exhibiting symptoms. These symptoms included oval-shaped tan necrosis surrounded by a bright halo. The three representative isolates exhibited irregular mycelial growth on V8-potato dextrose agar and produced pseudothecia. Based on the concatenated sequence datasets of four multi-genes, including the internal transcribed spacer, large subunit ribosomal RNA, glyceraldehyde-3-phosphate dehydrogenase, and RNA polymerase II second-largest subunit genes, phylogenetic analysis revealed that these three isolates clustered in the same clade as P. tritici-repentis. Results of pathogenicity test indicated that the initial symptoms appeared 5 days post-inoculation (dpi), with typical tan spot symptoms developing at 7 dpi. The pathogen was successfully re-isolated from the symptomatic tissues, thus fulfilling Koch's postulates. Furthermore, we selected three fungicides that effectively inhibited the mycelial growth of P. tritici-repentis by more than 90% in vitro. To the best of our knowledge, this is the first report of tan spot disease in wheat in Korea.

Discrimination of Cucumber mosaic virus and Broad bean wilt virus 2 Using Local Lesions on Vigna sinensis (동부(Vigna sinensis)의 국부병반을 이용한 Cucumber mosaic virus와 Broad bean wilt virus 2의 구별)

  • Bae, Sun-Hwa;Kim, Mi-Soon;Jung, Min-Young;Kwon, Soon-Bae;Ryu, Ki-Hyun;Kim, Kook-Hyung;Choi, Jang-Kyung
    • Research in Plant Disease
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    • v.12 no.3
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    • pp.221-225
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    • 2006
  • Cucumber mosaic virus(CMV) and Broad bean wilt virus 2(BBWV2) were isolated from Gentiana scabra plants showing typical mosaic and yellowing symptoms. When the inoculum of mosaic symptom propagated in Nicotiana benthamiana was inoculated to primary leaves of Vigna sinensis, the local lesions of different types was developed. Type one produced a small necrotic spot(SNS) of pinpoint type, while the other one showed a large necrotic spot(LNS) of halo type. LNS on primary leaves of V. sinensis was also induced by inoculum from yellowing symptom on G scabra. Single lesion from SNS induced a typical mosaic symptom on N. Benthamiana. On the other hand, LNS produced a chlorotic ring symptom on inoculated leaves and mosaic plus necrotic ringspot on upper leaves of N. benthamiana. An isolate of CMV from SNS and BBWV2 from LNS were detected by using dsRNA analysis, RT-PCR and agar gel double-diffusion test. Thus, our results should provide a tool of a simple method for discrimination from mixed infected plants by CMV and BBWV2.

The Surface Property and Shear Bonding Strength according to Composition of Ni-Cr alloy for Porcelain Fused to Metal Crown (도재용착주조관용 Ni-Cr계 합금의 조성에 따른 표면특성 및 전단결합강도 관찰)

  • Kim, Kap-Jin;Chung, In-Sung;Choi, Sung-Min
    • Journal of Technologic Dentistry
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    • v.35 no.2
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    • pp.113-120
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    • 2013
  • Purpose: This study was to observe surface property and bonding strength according to composition of Ni-Cr alloy for porcelain fused to metal crown. The two kinds of Ni-Cr alloy with different composition ratio of parent metal were observed general properties and chemical properties of each alloy surface and measured the shear bonding strength between ceramic and each alloys. The aim of study was to suggest the material for design of parent metal's composition ratio to development of alloy for porcelain fused to metal crown. Methods: The two kinds of alloy as test specimen was Ni(71wt.%)-Cr(12wt.%) and Ni(63wt.%)-Cr(23wt.%) alloy. The oxide on surface was observed by SEM and EDX. And the shear test was performed by MTS. Results: The surface property and oxide characteristic analysis of oxide layer, weight percentage of Element O within $Ni_{71}Cr_{12}$ alloy measured 12.74wt.%, but $Ni_{63}Cr_{23}$ alloy was measured 15.91wt.%. And the maximum shear bonding strength was measured 106.14MPa between $Ni_{71}Cr_{12}$ alloy and vintage halo (VV group). Conclusion: The surface property and oxide characteristic of $Ni_{71}Cr_{12}$ alloy was similar to $Ni_{63}Cr_{23}$ alloy. And VV group has the strongest shear bonding strength.