• International Journal of Korean Welding Society
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• 제4권1호
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• pp.46-52
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• 2004

To combine the mechanical advantages of ceramics with those of metals, one often uses both materials within one composite component. But, as known, they have different material properties and fracture behaviors. In this study, a four-point bending test is carried out on $Si_3N_4$ joined to ANSI 304L stainless steel with a Ti-Ag-Cu filler and a Cu interlayer at room temperature to evaluate their longitudinal strain behaviors. And, to detect localized strain, a couple of strain gages are pasted near the joint interfaces of the ceramic and metal sides. The normal strain rates are varied from $3.33{\times}10^5$ to $3.33{\times}10^{-1}s^{-1}$ Within this range, the experimental results showed that the four-point bending strength and the deflection of the interlayer increased with increasing the strain rate.

• 대한기계학회논문집A
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• 제26권3호
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• pp.521-527
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• 2002

In this paper, tensile behavior and low cycle fatigue behavior of 316L stainless steel which is currently favored structural material for several high temperature components such as the liquid metal cooled fast breeder reactor (LMFBR) were investigated. Research was performed at 55$0^{\circ}C$, $600^{\circ}C$ and $650^{\circ}C$ since working temperature of 316L stainless steel in a real field is from 40$0^{\circ}C$ to $650^{\circ}C$. From tensile tests performed by strain controls with $1{\times}10^{-3}/s,\; l{\times}10^{ -4}/s \;and\; 1{\times}10/^{ -5}/ s $ strain rates at each temperature, negative strain rate response (that is, strain hardening decreases as strain rate increases) and negative temperature response were observed. Strain rate effect was relatively small compared with temperature effect. LCF tests with a constant total strain amplitude were performed by strain control with a high temperature extensometer at R.T, 55$0^{\circ}C$, $600^{\circ}C$, $650^{\circ}C$ and total strain amplitudes of 0.3%~0.8% were used and test strain rates were $1{times}10^{-2} /s,\; 1{times}10^{-3} /s\; and\; 1{times}10^{-4} /s$. A new energy based LCF life prediction model which can explain the effects of temperature, strain amplitude and strain rate on fatigue life was proposed and its excellency was verified by comparing with currently used models.

• Journal of the Korean Physical Society
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• 제81권
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• pp.133-138
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• 2022

Using the first principles calculations, we investigated the strain dependent magnetic properties of the 1T-VSe₂ monolayer (up to ± 3%). We obtained a metallic band structure, and this feature was preserved under both compressive and tensile strain. The pristine system had a magnetic moment of 0.9 µ_B/unit cell and decreased to 0.68 µ_B/unit cell under - 3% compressive strain whereas it was increased to 1.03 µ_B/unit cell under + 3% tensile strain. The 1T-VSe₂ monolayer had an in-plane magnetic anisotropy with a value of - 0.48 meV/cell. The in-plane anisotropy features were maintained in both compressive and tensile strains. The orbital resolved magnetic anisotropy indicated that the V atom contributed to the perpendicular magnetic anisotropy while the Se atom had an in-plane anisotropy. We found that the Se dominated the anisotropy. We also calculated the temperature dependent Curie temperature (T_C). The pristine structure had a T_C of 260 K, and the strain effect enhanced the T_C. Particularly, the compressive strain affected further the exchange parameter resulting in substantial enhancement of the Curie temperature where a T_C of 570 K was achieved at - 3% strain. Our finding regarding the strained VSe₂ could help for further investigation in spintronics and straintronics applications.

• 대한치과보철학회지
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• 제43권3호
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• pp.322-330
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• 2005

Statement of problem. In distal extension removable partial denture, the preservation of health of abutment teeth is very important, but abutment teeth are subjected to unfavorable stress. Purpose. The purpose of this study was to investigate the biomechanical effects of mandibular removable partial dentures with various prosthetic designs using strain gauge analysis. Material and methods. Artificial teeth of both canines were anchored bilaterally in a mandibular edentulous model made of resin. Bilateral distal extension removable partial dentures with splinted and unsplinted abutments were fabricated. Group 1 : Clasp-retained mandibular removable partial denture with unsplinted abuhnents Group 2 : Clasp-retained mandibular removable partial denture with splinted abutments by 6-unit bridge Group 3 : Bar-retained mandibular removable partial denture Strain gauges were bonded on the labial plate of the mandibular resin model, approximately 2 mm close to the abutments. Two vertical experimental loadings (100N and 200N) were applied subsequently via two miniature load cells that were placed at mandibular first molar regions. Strain measurements were performed and simultaneously monitored from a computer connected to data acquisition system. For within-group evaluations, t-test was used to compare the strain values and for between-group comparisons, a one-way analysis of variance (ANOVA) was used and Duncan test was used as post hoc comparisons. Results. Strain values increased as the applied load increased from 100N to 200N for all groups (p<.05). The strain values of group 1 and 2 were tensile under loadings. In contrast, strain values of group 3 were compressive in nature. Under 100N loading, group 1 showed higher strain values than group 3 in absolute quantity (p<.05). Under 200N loading, group 3 showed higher strain values than group 1 and 2 in absolute quantity (p<.05). Group 1 showed higher strain values than group 2 (p<.05). Conclusion. Splinting of two isolated abutments by bridge reduced the peri-abutment strain in comparison with unsplinted abutments. Strain of bar-retained removable partial denture increased much more as applied load increased, but was compressive in nature.

• 대한수의학회지
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• 제18권1호
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• pp.27-31
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• 1978

In order to identify unknown Babesia spp. which was isolated from Korean cattle, the morphology of Korean strain was compared with that of Babesia bigemina (Kochinda strain) and Babesia spp. (Miyake strain). Immunofluorescent technique was used to identify the serological character of the parasites. The results obtained were summarized as follows: 1. Korean strain was morphologically very similar to Babesia spp.(Miyake strain) which mostly showed parallel-bigeminate forms, while B. bigemina (Kochinda strain) was mostly round and oval forms. 2. By the indirect fluorescent antibody technique: a) Anti-Babesia spp. and Korean Babesia spp. sera showed a higher antibody titers with Babesia spp. (Miyake strain) antigen (1:500) than with B. bigemina (Kochinda strain) antigen (1:50). b) Anti-Babesia bigemina sera showed a lower titer with Babesia spp. antigen (1:50) than with B. bigemina antigen (1:250). 3. On the basis of morphological and serological confirmantions, a Babesia strain isolated from a Korean cattle was very similar, if not identical, to Miyake strain of Babesia spp.

• 한국미생물·생명공학회지
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• 제3권3호
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• pp.123-134
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• 1975

야생효모균을 이용한 기효사요의 제조 및 사양시험에서 균체와 각종효소를 이용할 목적으로 자연계로부터 효모구 96균주를 분이한 것 중에서 5균주를 선정하여 액체배양한 것을 탈지강, 대맥양소맥면 및 톱밥 등을 혼합한(A, B, C, D및 E)것을 발효사요를 만들어 사양한 결과는 다음과 같다. 1. 발효사요 제조에 이용한 난주는 5주로 Strain No. 225 Hansenula anomala var. anomala, No. 400 Candide pelliculosa, No. 416-C Debaryomyces hansenii 및 No. 403-A Irpex lacteus등이다. 2. 선정균주의 액체배양조건은 Strain No. 225, 400, 405, 416-C 및403-A의 생육최적 pH 5.0~5.5이고 최적당도는 Bllg. $10^{\circ}$였다. 또한 A) Strain No. 225, 400, 및 403-A와 C) Strain No. 225, 405 및 403-A생육온도는 35$^{\circ}C$, 3) Strain No. 225, 400, 416-C의 최적온도는 3$0^{\circ}C$였다. Strain No. 225, 400, 405, 416-C는 최고 35$^{\circ}C$ 이상과 No. 403-A는 최고 4$0^{\circ}C$ 이상의 온도에서도 생육이 되었다. 3. Strain No. 225와 403-A는 골세포가 크며, Strain No. 225와 405는 당의 발효능이 강하고 Strain No. 225, 400, 405 및 416-C 는 Cellobiose를 Strain No. 225, 400 및 416-C등은 xylose와 soluble starch등을 동화하였다. 그러나 Strain No. 416-C만은 Inulin Strain No. 223, 400. 405 및 402-A등은 질산염 (KNO$_2$, KNO$_3$등)을 동화하는 균예이다. 4. Strain No. 403-A는 효모수사균으로cellulase를 분필하는 균수로 식물성장기유이기 때문에 다른 효모균의 증식을 도와 원요중에 효소를 생성하였다. 5. 발언사요 제조에 이용한 혼합거의 배합비는 A) 배합사료, B)탈지당 및 대맥당(1:1), C) 탈지당 및 소맥당(1:1) D) 탈지당, 소맥당 및 대맥당(1:1:1), 그리고 E) 탈지당, 소맥당 및 톱밥(1:1:1)등을 사용하였다. 6. 효모균 발효사료는 혼합강류(A,B,C,D및 E등)의 원료배합으로 양호하였으며 황산암모니움을 0.3% 첨가하여 수분양은 60~70% 배양온도는 25~3$0^{\circ}C$에서 유지시켰다. 혼합강류에 균주의 접종은 각각 전배양한 A) Strain No. 225, 400, 403-A, B) Strain No. 225, 400, 416-C, C) Strain No. 400, 405, 403-A 그리고 D)와 E)의 균주들은 A), C)와 같다. 전배양액에 4% glucose 용액을 3배양첨가 희석 부하고 원료중량 5%(w/w)되게 접종하여 공처기간은 2~3일간이 최적조건이었다. 7. 혼합강류로 만든 발효사료 중 단백질 증가율은 A) 배합사료는 4.46%, B) 탈지당 및 소맥당(1:1)을 2.81% C) 탈지당 및 소맥당(1:1)는 6.12% D) 탈지당, 소맥당 및 대맥당(1:1:1)은 2.51% 그러고 E) 탈지당, 소맥당 톱밥(1:1:1)은 2.55%였다. 8. 발효사료로서 배양시험은 담염동물로서 육계전용종(Starcros; male) 180수와 말발효사가는 탈지당 및 소맥당(1:1)로 혼합한 사로와 야생효모균주(C)로 발효시킨 사요간의 가치를 비교하여 첨가수준(20%, 15% 및 10%)에 의한 효과를 구명하기 위하여 8주간 실시하였다. 9. 미발효구 A-a구에서 개시할 때 체중 35.67g였든 것이 8주시 종료시는 622.7g로 총증체양 587.03g로 일당 10.47g인데 반하여 발효구인 B-a구에서는 총증용양 845.13g로 일당증체양 15.08g였다. 10. 시험기간 중 섭취량에 있어서도 발효구 미발효구에 비하여 양호하였고 출가수출간에도 차이가 있었는데 10%구 2.552g>15%구 2.559g>20%구 2.223g 순위였다. 미발효 20% 첨가구인 A-a구가 지구에 비하여 증체풍과 사요섭취량이 떨어진 것은 의 배합에 기인하는 것으로 생각되며 같은 수준의 발효사료를 배합한 B-a구가 타구에 비해서 생육성적이 좋은 것은 발효로 인한 기호성의 향상에 기인한 것으로 생각된다. 11. 폐사율은 A-a구에서 4주이상 2전가 폐사하였고 타구에서는 전혀 없었다 이상과 같은 결과로 보아 본 연구에서 야생효모근 3균주를 혼합광유에 정종배양하여 제조한 발효사료는 균예성분의 이용으로 균용도 생물과 같이 각종 영양소로 될 것이다. 효모가 생성하는 체소이외의 생성물의 이용 등을 들수있어 소화작용에 대한 보조적인 역할이 될 것이며 다량으로 배양하면 값이 싸고, 영양가치가 높은 발효사료의 체조 및 사양이 가능하다고 본다.

• 한국연소학회지
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• 제5권1호
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• pp.7-18
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• 2000

Numerical simulations of counterflow non-premixed $CH_4/C_2HCl_3/Air$ flames added 8%(by volume) C2HCl3 on the fuel side are conducted at atmospheric pressure using a detailed chemical reaction mechanism in order to understand the effect of strain rates. A detailed sensitivity analysis is also performed in order to assess the relative influence of each reaction on the flame established at a strain rate of 200s-1. The structure of flames (i.e., temperature, velocity, and concentration of species) established at both a strain rate of 150s-1 and 300s-1 are investigated. As the strain rate increases, the "flame zone" is restricted to a narrower range and the position of maximum temperature is shifted to the fuel side. The concentrations of major species, H2O, CO, H2, HCl, Cl2, and Cl are decreased with increased strain rate. The reaction involving chlorine, CH4 + Cl $\rightarrow$ CH3 + HCl, instead of the reaction, CH4 + H $\rightarrow$ CH3 + H2 influences the consumption of methane. C2HCl3 + OH $\rightarrow$ CHCl2 + CHOCl and HCl + OH $\rightarrow$ H2O + Cl, are major reactions, through which OH radicals are consumed.

• 한국산림과학회지
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• 제96권1호
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• pp.1-6
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• 2007

홍가슴루리잎벌(Arge captiva)과 장미등애잎벌(A. pagana pagana), 극동등애잎벌(A. similis)의 환경친화적 방제를 위하여 곤충병원성 선충(Heterorhabditis sp. 경산 계통, Steinernema carpocapsae GSN1 계통, S. feltiae Monteri 계통, S. glaseri 동래 계통, S. longicaudum 논산 계통, S. monticolum 지리 계통)을 이용하여 실내와 포트에서 실험을 수행하였다. 홍가슴루리잎벌 3령충에 대한 곤충병원성 선충의 병원성은 S. carpocapsae GSN1 계통과 S. feltiae Monteri 계통 처리 시, 처리 5일 후 100%의 치사율을 보였다. 홍가슴루리잎벌레 3령충에 침입한 선충의 수는 S. glaseri 동래 계통의 경우 10.2마리였으며 S. carpocapsae GSN1 계통은 4.2마리였다. 장미등애잎벌의 령기별에 따른 S. carpocapsae GSN1 계통의 병원성은 노숙화 될수록 높아 2령충과 3령충, 4령충에 대한 반수치사농도($LC_{50}$)는 각각 11.5, 9.3, 8.4 마리였다. Pot 실험에서 S. carpocapsae GSN1 계통을 $2{\times}10^9$마리/ha 농도로 처리 시, 홍가슴루리잎벌과 장미등애잎벌, 극동등애잎벌의 보정사충율은 각각 72.5, 85.0, 85.0%를 나타내었다.

• 미생물학회지
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• 제10권1호
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• pp.9-28
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• 1972

1. To get the suitable yeasts for the tratment of waste liquor from pulp and paper industries, the 162 yeasts were isolated from the waste liquor, decayed trees and sewage (1, 7, 8, 9, 1971). 17 species were chosen by its ability to assimilate the carbon compounds and indentified. 2. All of the strain was increased its growing ability by agitation. In particular, the strain 912, strain 613, strain 100, strain 732 showed excellent high productive ratio(A/$A_{0}$). 3. The optimum temperature of the strains rangel $27^{\circ}C$ and $30^{\circ}C$. 4. Most of the strain was grown actively in 10C/5N-composition and strain 113, strain 432, strain 735, strain 936, and strain 912 showed its optimum growing in 15C/5N-composition and 5C/5N-composition, respectively. 5. The optimum pH of the strains lay within range pH 4.5-6. Effect of the variation of pH on the growth was nearly negligible within this range. 6. The strain 912, strain 100, strain 613, strain 311, strain 235, and strain 732 were expected for the utilization to the treatment of the waste liquor from pulp and paper industries.

• 대한치과보철학회지
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• 제45권6호
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• pp.735-742
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• 2007

Statement of problem. Although a number of previous investigations have been carried out on the polymerization shrinkage-strain kinetics of provisional crown and fixed partial denture (FPD) materials, the effect of the changes of liquid monomer to powder ratio on its polymerization shrinkage-strain kinetics has not been reported. Purpose. The purpose of this study was to investigate the influence of liquid monomer to powder ratio of polymer-based provisional crown and FPD materials on the polymerization shrinkage-strain kinetics. Material and methods. Chemically activated acrylic provisional materials (Alike, Jet, Snap) were investigated. Each material was mixed with different liquid monomer to powder ratios by volume (1.0:3.0, 1.0:2.5, 1.0:2.0, 1.0:1.5, 1.0:1.0). Time dependent polymerization shrinkage- strain kinetics of all materials was measured by the bonded-disk method as a function of time at $23^{\circ}C$. Five recordings were taken for each ratio. The results were statistically analyzed using one-way ANOVA and the multiple comparison Scheffe test at the significance level of 0.05. Trends were also examined by linear regression. Results. At 5 minutes after mixing, the polymerization shrinkage-strains of all materials ranged from only 0.01% to 0.49%. At 10 minutes, the shrinkage-strain of Alike was the highest, 3.45% (liquid monomer to powder ratio=1.0:3.0). Jet and Snap were 2.69% (1.0:2.0) and 1.58% (1.0:3.0), respectively (P>0.05). Most shrinkage (94.3%-96.5%) occurred at 30 minutes after mixing for liquid monomer to powder ratio, ranging from 1.0:3.0 to 1.0:1.0. The highest polymerization shrinkage-strain values were observed for the liquid monomer to powder ratio of 1.0:3.0. At 120 minutes after mixing, the shrinkage-strain values were 4.67%, 4.18%, and 3.07% for Jet, Alike, and Snap, respectively. As the liquid monomer to powder ratio increased, the shrinkage-strain values tend to be decreased linearly (r=-0.769 for Alike, -0.717 for Jet, -0.435 for Snap, $r^2=0.592$ for Alike, 0.515 for Jet, 0.189 for Snap; P<0.05). Conclusion. The increase of the liquid monomer to powder ratio from 1.0:3.0 to 1.0:1.0 had a significant effect on the shrinkage-strain kinetics of polymer-based crown and FPD materials investigated. This increased the working time and decreased the shrinkage-strain during polymerization.