• Bulletin of the Korean Chemical Society
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• 제27권12호
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• pp.2028-2036
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• 2006

The combined ab initio and vibrational predissociation (VP) spectroscopic studies on methylammonium-$(water)_4$ complex aimed at understanding the hydration behavior of an amphiphilic ion core are described. The ab initio calculations predicted eleven low-energy isomers forming cyclic, tripod, chain, and caged structures, and their relative stabilities, total hydration energies and thermodynamic functions at 298 K and 150 K. The excellent correlation between the observed VP spectra and ab initio spectra for bonded N-H, bonded O-H and free O-H stretches suggested co-existence of five cyclic isomers and two non-cyclic isomers in ion beam at 150 K, consistent with the trends of calculated Gibbs free energies.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1370-1376
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• 2008

The structure of railroad or subway is that low fare transportation system of the large traffic volume. Like this structure is subjected to the cyclic load of moving vehicle. Consequently the result of the settlement analysis or plastic deformation prediction of railroad bed could be used as an important factor in safety of the railroad. The results of cyclic triaxial test were used in the numerical analysis of power model which Li and Selig(1994) developed. The soil samples were obtained from the construction site of railroad. Cyclic triaxial test was conducted with the variation of the magnitude of cyclic load and soil types. The large magnitude of plastic deformation in the railroad bed is caused of structure failure of the railroad.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권2호
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• pp.671-678
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• 2019

In this paper, the low cycle fatigue failure and ratcheting behavior, as well as their interaction of AH32 steel were experimentally investigated under uniaxial cyclic loading. The effects of mean stress, stress amplitude and stress ratio on the low cycle fatigue life and ratcheting strain were discussed. It was found that the ratcheting strain increased while the fatigue life decreased with the increase of mean stress and stress amplitude, and the increasing stress ratio would result in smaller ratcheting and larger fatigue life. Two kinds of failure modes, i.e. low cycle fatigue failure due to crack propagates and ratcheting failure due to large plastic strain will take place respectively. Based on the experimental results, considered the effect of ratcheting on fatigue life, a model with the maximum stress and ratcheting strain rate was proposed. Comparison with the experimental result showed that the new model provided a good prediction for AH32 steel.

• 한국조리학회지
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• 제20권1호
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• pp.55-64
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• 2014

블루베리를 열풍건조, 순환형 감압건조 및 동결건조의 방법으로 건조제품을 제조하여 품질특성과 생리활성을 비교조사 하였다. 일반성분 중 가장 많이 함유하고 있는 성분은 건조방법과 무관하게 탄수화물(68.48~80.00%)이었으며, 다음으로 수분(13.10~27.93%), 조단백질(1.63~5.41%), 조지방(0.58~1.25%) 및 회분(0.71~1.11%) 순으로 나타났다. pH는 순환형 감압건조시료의 pH가 유의적 차이가 없었으며, 갈변도의 경우 0.31~0.21의 값으로 건조 방법별로 차이가 많았다. 색도는 L값과 a값은 동결 건조한 시료가 더 높게 나타난 반면, b값의 경우 열풍, 순환형, 동결건조시료 순으로 높은 값을 나타내었다. 열풍 건조한 시료의 비타민 C 함량은 5.6 mg/100g이었으며, 순환형 감압건조 및 동결건조 시료의 비타민 C 함량은 6.9 mg/100g, 7.1 mg/100g으로 나타났다. 안토시아닌 함량은 10.08 mg/100g, 29.41 mg/100g, 33.87 mg/100g의 함량을 나타내어 안토시아닌 함량 역시 동결건조시료에서 더 높은 수치를 나타내었다. 열풍건조시료의 유리당 함량이 695.5 mg/100g으로 가장 높게 나타났다. 페놀함량과 DPPH 라디칼 소거능은 순환형 감압 건조 및 동결 건조가 높게 나타났다.

• 열처리공학회지
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• 제24권2호
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• pp.92-98
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• 2011

The influence of the cooling condition after solution treatment on the high temperature fatigue resistance of 23Cr-26Ni heat resistant steel was investigated. Two different cooling conditions were applied to the steel after solution treatment at $1200^{\circ}C$ for 3 hours. One specimen was water quenched immediately after the solution treatment. The other one was furnace cooled at a rate of $0.5^{\circ}C/min$ down to $750^{\circ}C$ after the solution treatment. Then, both specimens were aged at $750^{\circ}C$ for 5 hours. Under two different heat treatment conditions, the low cycle fatigue (LCF) test was performed at $600^{\circ}C$ and room temperature (RT). Only cyclic hardening continued from the beginning until fracture at all strain amplitudes during LCF at $600^{\circ}C$. This phenomenon was attributed to the increase in the dislocation density due to cyclic deformation, which resulted in the interaction between the newly created dislocations and precipitates. Cyclic hardening followed by saturation and cyclic softening was observed at RT. Cyclic softening was attributed to the dislocation annihilation rate exceeding the dislocation generation rate. Other probable factor for cyclic softening was some cavities formed around grain boundaries after 20 cycles. WQ and FC have a similar LCF behavior at RT and $600^{\circ}C$ as shown in the cyclic stress response curves.

• Food Science and Biotechnology
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• 제16권4호
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• pp.520-525
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• 2007

The physicochemical properties of sun-dried and cyclic freeze-thaw dried Alaska pollack were analyzed to compare the 2 drying processes. The moisture content and water activity of sun-dried Alaska pollack were higher than cyclic freeze-thaw dried and 1 year-aged cyclic freeze-thaw dried Alaska pollack (hwangtae). The relatively low temperatures used in cyclic freeze-thaw drying retards lipid oxidation compared to sun drying based on the acid and peroxide values, and the levels of thiobarbituric acid-reactive substances (TBARS) in the dried fish. The water holding capacity of cyclic freeze-thaw dried Alaska pollack aged for 1 year (hwangtae) under ambient conditions at the drying location was higher than that of sun-dried Alaska pollack. The swelling of myofibrilar filaments during cyclic freeze-thaw drying may be responsible for the softening of the dried muscle protein. Aging the cyclic freeze-thaw dried Alaska pollack for 1 year contributed to an increased yellowish color of the hwangtae.

• Journal of information and communication convergence engineering
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• 제4권4호
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• pp.136-140
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• 2006

In this paper, we consider the detection of orthogonal space-time block codes (OSTBCs) without channel state information (CSI) at the receiver. Based on the conventional blind cyclic decoder, we propose an enhanced blind cyclic decoder which has higher system performance than the conventional one. Furthermore, the proposed decoder offers low complexity since it does not require the computation of singular value decomposition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1048-1050
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• 1995

Lead-acid battery is used widely as a power source at a automobile, industrial machines, folk lifts, U.P.S. etc. Lead-acid battery is cheaper than arty other secondary battery, but this battery has many disadvantages such as heavy, low energy density, environment problem etc. In this article, we introduce cyclic voltammetry methods to investigate corrosion behaviour of positive grids of Pb-Ca alleys.

• Geomechanics and Engineering
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• 제7권5호
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• pp.569-587
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• 2014

Triaxial compression creep tests were performed on salt rock samples using cyclic confining pressure with a static axial pressure. The test results show that, up to a certain time, changes in the confining pressure have little influence on creep properties of salt rock, and the axial creep curve is smooth. After this point, the axial creep curve clearly fluctuates with the confining pressure, and is approximately a straight line both when the confining pressure decreases and when it increases within one cycle period. The slope of these lines differs: it is greater when the confining pressure decreases than when it increases. In accordance with rheology model theory, axial creep equations were deduced for Maxwell and Kelvin models under cyclic loading. These were combined to establish an axial creep equation for the Burgers model. We supposed that damage evolution follows an exponential law during creep process and replaced the apparent stress in creep equation for the Burgers model with the effective stress, the axial creep damage equation for the Burgers model was obtained. The model suitability was verified using creep test results for salt rock. The fitting curves are in excellent agreement with the test curves, so the proposed model can well reflect the creep behavior of salt rock under low-frequency cyclic loading. In particular, it reflects the fluctuations in creep deformation and creep rate as the confining pressure increasing and decreasing under different cycle periods.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.617-620
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• 1999

The purpose of this study is to find the influence of interface and confinement on bond between reinforcing steel and concrete subjected to monotonic and cyclic loading. The key variables for the experimental program include rib height, rib spacing for reinforcing bars and confinement. From the results obtained in this study, the following main observations can be made for the bond properties. Bond strength increases when confinement increases under monotonic and cyclic loading. Bond stiffness and strength drop remarkably after the maximum bond strength. Both bond stiffness and strength also drop at a constant slip when the number of cyclic loading increase. The bond resistance subjected to cyclic loading decreases significantly for reinforcing bars with low rib height.