• Journal of Animal Science and Technology
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• 제58권2호
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• pp.5.1-5.9
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• 2016

Background: The milk yield can be affected by the frequency of milking per day, in dairy cows. Previous studies have shown that the milk yield is increased by 6.25 % per lactation when the milking frequency is increased from 2 to 3 times per day while the somatic cell count is decreased. To investigate the effect of milking frequency (3X vs. 4X) on milk yield and it's genetic parameters in the first and second lactations of the Iranian Holstein dairy cows, a total of 142,604 test day (TD) records of milk yield were measured on 20,762 cows. Results: Heritability estimates of milk yield were 0.25 and 0.19 for 3X milking frequency and 0.34 and 0.26 for 4X milking frequency throughout the first and second lactations, respectively. Repeatability estimates of milk yield were 0.70 and 0.71 for 3X milking frequency and 0.76 and 0.77 for 4X milking frequency, respectively. In comparison with 3X milking frequency, the milk yield of the first and second lactations was increased by 11.6 and 12.2 %, respectively when 4X was used (p < 0.01). Conclusions: Results of this research demonstrated that increasing milking frequency led to an increase in heritability and repeatability of milk yield. The current investigation provided clear evidences for the benefits of using 4X milking frequency instead of 3X in Iranian Holstein dairy cows.

• 대한기계학회논문집B
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• 제37권1호
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• pp.19-25
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• 2013

본 연구에서는 벌지 실험을 이용하여 티타늄 박막의 기계적 물성을 측정하였다. 벌지 실험은 외적 지지구조를 가지지 않는 박막 시편의 한 면에 일정한 압력을 가하여 박막의 변위를 측정, 압력과 변위의 관계를 이용하여 박막의 기계적 물성을 측정하는 실험이다. 스퍼터링을 이용해 증착된 티타늄 박막의 두께는 1.0, 1.5, $2.0{\mu}m$ 이고, 물성의 열처리 시간에 대한 영향을 알아보기 위해 증착된 시편은 $600^{\circ}C$에서 각각 150, 300, 600 초 동안 열처리 되었다. 박막의 탄성 계수, 잔류 응력, 항복 응력이 벌지 실험을 통해 측정되었고, 실험 결과 항복 응력은 열처리 시간에 의존하는 특성을 확인하였다. 또한 시편 두께가 감소할수록 강도가 증가하는 크기효과를 관찰하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.1091-1096
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• 2003

Pullout tests of single headed bars using plain concrete blocks indicate that the embedment depth of $10d_b$ is in general required for the headed bars to develop pullout strength equivalent to 125% of bar yield strength. In this experimental study, test results of multiple headed bars installed in reinforced concrete column sections are presented. Test variables included embedment depth, column main reinforcement ratio, and spacing of column ties. 2D29 bars were pulled out at one time from normal strength concrete. Test results indicated that the embedment depths, column tie spacings, and column main reinforcement ratios all influenced the pullout strengths of the headed bars. When the embedment depth was not sufficient, narrow tie spacings especially resulted in increased pullout strengths of the headed bars. Test results also indicated that the embedment depth of 15㏈ was sufficient for the closely spaced two headed bars (head-to-head spacing =$6d_b$) to develop pullout strength equivalent to 125% of the bar yield strength.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권5호
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• pp.247-251
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• 2004

We report highly improved yield strength of nickel thin film, prepared using electroplating. The micro-scaled nickel cantilever is found to have significantly higher yield strength than bulk nickel. For the yield strength test, the heights of the micro-scaled cantilever were varied up to 60 ${\mu}{\textrm}{m}$ and electrostatic force was used for actuation. Stress of the bent cantilever was estimated using the FEM large deflection model. The yield strength of the thin nickel film is found to be over five times higher than that of the bulk nickel previously published. Results from this study indicate that metal microstructures can be used for MEMS applications requiring large deflection.

• 대한임상검사과학회지
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• 제38권1호
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• pp.1-8
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• 2006

The purposes of this study were to evaluate the changes in hematologic indices after plateletpheresis and to identify the preapheresis platelet count and clinical factors (age, gender, height, and weight) that showed some influence on the percentage of platelet decrement, yield and efficiency. Plateletpheresis was performed on 101 healthy donors in Bundang CHA general hospital. The data was analyzed using the SAS program with t-test, ANOVA test and Multiple regression. The mean percentage decrease after plateletpheresis was 2.0% in hemoglobin, 1.8% in hematocrit, and 29.7% in the platelet count, while a WBC count showed an increase of 2.6%. The mean percentage decrease of hemoglobin and hematocrit were 1.7% and 1.4%, in males and 3.6% and 3.7% in females, respectively. Particularly the percentage decrease of platelet count was significantly higher in females (40.0%) than in males (27.2%). The platelet decrementage and yield were significantly higher in females, but the efficiency did not differ significantly between males and females. The yield showed the lowest levels in subjects who were 40 years old or over but the platelet decrement and efficiency did not change according to age. The platelet decrement increased as height and weight increased. Also, the platelet decrement and yield increased as the initial platelet counts increased, but the efficiency did not. From multiple regression analysis, the platelet decrement was associated with gender, weight, and initial platelet count. The yield was related to the initial platelet count, but the efficiency was not related to gender, age, weight, height or initial platelet counts. This study has a limitation of the generality of the study results since this study was conducted only in a single university hospital. Further study would be necessary to find out a subpopulation that is sensitive to the hematologic change after plateletpheresis, and to determine the standard criteria for blood donation based on the subpopulation.

• 소성∙가공
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• 제18권5호
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• pp.416-421
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• 2009

The applications of the aluminum alloy sheets to the auto-body panels are dramatically increasing for weight reduction of the automobiles. However, low formability of the aluminum alloy sheet compared to the steel sheet can be obstacles in tool manufacturing processes. Therefore, many of yield criteria for the anisotropic materials such as the aluminum alloy sheet have been observed. In this study, the biaxial tensile test and FLD test for the aluminum alloy sheet are performed. The results are compared with Hill's 1948 and Hill's 1990 models by means of theoretical predictions. Finite element analysis was also performed using the proposed method for the real panel.

• 대한화장품학회지
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• 제22권2호
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• pp.89-98
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• 1996

A novel polymeric sunscreen agent was developed. It was prepared by the coupling reaction of 2-ethylhexyl 4-hydroxycinnamate with poly vinylbenzyl chloride(PVBC, average MW 6,500). In this reaction the reactivity was mostly affected by catalyst. In the absence of catalyst the yield was approximately 55% and in the presence of tetrabutylammonium bromide the yield was about 65%, but in the presence of tetrabutylammonium iodide the yield was 100% to give a average molecular weight 20,000 polymeric sunscreen agent. There were no side reactions, and its structure and purity were confirmed by various analytical methods, such as NMR, IR, and so on. UV radiation absorption efficiency is more than 70% compared with that of octyl methoxycinnamate. The solubility in polar oil, for example C12-15 alkylbenzoate and caprylic/capric triglyceride, is more than 50%. It showed high stability in the time course of test including acceleration test. This polymer is safe to skin because of poor permeability to skin, no side products in the process of preparing, and easy elimination of excess starting materials.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.164-167
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• 2009

The applications of the aluminum alloy sheets to the auto-body panels are dramatically increasing for weight reduction of the automobiles. However, low formability of the aluminum alloy sheet compare to the steel sheet can be obstacles in tool manufacturing process. Therefore, much of yield criteria for the anisotropic material such as the aluminum alloy sheet have been observed. In this study, the biaxial tensile test and FLD test for the aluminum alloy sheet are performed. The results are compared with Hill's 1948 and Hill's 1990 model by means of theoretical predictions. Finite element analysis also performed using the proposed method for the real panel.

• 산업기술연구
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• 제20권B호
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• pp.131-138
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• 2000

In this paper, we would like to develop the bending collapse specific equation of aluminum members which are usually used in light-weight vehicle or electromobiles. The result of the developed equation are compared with that of test and finite element methods as the moment-rotational angle curves. Three types of aluminum members are tested with the pure bending collapse test rig. PAM-CRASH and ABAQUS program are used for finite element analysis. As the result the developed bending collapse governing equation is accurate in estimating the yield moment and the maximum moment. Especially, in the case of the local buckling and the delayed buckling, the developed equation is better effective than F.E.M.

• ETRI Journal
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• 제32권4호
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• pp.642-644
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• 2010

With the rapid increase occurring in both the capacity and density of memory products, test and repair issues have become highly challenging. Memory repair is an effective and essential methodology for improving memory yield. An SoC utilizes built-in redundancy analysis (BIRA) with built-in self-test for improving memory yield and reliability. This letter proposes a new heuristic algorithm and new hardware architecture for the BIRA scheme. Experimental results indicate that the proposed algorithm shows near-optimal repair efficiency in combination with low area and time overheads.