• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권12호
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• pp.576-585
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• 2005

This paper deals with the electromagnetic field analysis of slotless brushless permanent magnet machines with three different magnetization patterns such as Halbach, parallel and radial magnetization. The magnetization modeling of Halbach, parallel and radial magnetization is performed analytically. And then, analytical solutions for open-circuit field distributions, armature reaction field distributions, flux linkages due to PMs and stator windings, torque, back-emf and inductance are derived in terms of magnetic vector potential and two-dimensional (2-d) polar coordinate systems. The analytical results are validated extensively by finite element (FE) analyses. The magnet volume required in order to produce identical flux density is compared with each magnetization. Finally, analytical solutions and derivation procedures of those presented in this paper can be applied to slotless and slotted brushless permanent magnet AC and DC machines.

• Journal of Mechanical Science and Technology
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• 제20권6호
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• pp.882-895
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• 2006

Surface and interfacial waves in two superposed horizontal inviscid fluids of finite depths are studied. The flow is induced by translating a vertical rigid plate with a prescribed velocity. Analytical solutions that accurately predict the motion of the free surface and the interface are obtained by using a small-Froude-number approximation. Three different velocities of the plate are considered, while flows induced by any arbitrary motion of the plate can be easily analyzed by a linear superposition of the solutions obtained. It is shown that pinching of the upper layer can occur for a sufficiently thin upper layer, which leads to its rupture into small segments. Other interesting phenomena, such as primary and secondary wiggles generated on the interface near the wavemaker, are discussed.

• Mass Spectrometry Letters
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• 제10권1호
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• pp.32-37
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• 2019

The ${\pi}-{\pi}$ interactions of the peptide-dimer and peptide-trimer complexes were investigated in the (VQIVYK + LYQLEN) and (VQIVYK + NNQQNY) mixing solutions. The results showed that tyrosine (Y) residues were critical in the formation of hetero peptide-dimers and -trimers during the early oligomerization process. We used collision-induced dissociation (CID) along with electrospray ionization mass spectroscopy (ESI-MS) to obtain the structural information of the hetero-dimers and -trimers. We chose three amyloidogenic peptides-VQIVYK, NNQQNY, and LYQLEN-from tau protein, yeast prion-like protein Sup35, and insulin chain A, respectively. Hetero-dimer, -trimer, -tetramer, and -pentamer complexes were observed in the mass spectra. The tandem mass spectrum of the hetero-dimer and hetero-trimer showed two different fragmentation patterns (covalent and non-covalent bond dissociation). Y-Y interaction structures were also proposed for the hetero-dimer and -trimer complexes.

• Journal of Korean Society for Atmospheric Environment
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• 제22권E2호
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• pp.78-88
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• 2006

In order to study the characteristics of cloud, a real-scale experiment for cloud generation was carried out using an extinct vertical mine (430 m height) located in the northeastern Honshu, Japan. The dry particles generated from the three-step concentrations of NaCl solutions were used for cloud generation. The number size distributions of initial dry particles and cloud droplets were monitored by Scanning Mobility Particle Sizer (SMPS) and Forward Scattering Spectrometer Probe (FSSP) at bottom and upper sites of pit, respectively. The polymeric water absorbent film (PWAF) method was employed to measure liquid water content ($W_L$) as a function of droplet size. Moreover the chemical properties of individual droplet replicas were determined by micro-PIXE. The CCN number concentration shows the lognormal form in dependence of the particle size, while the number size distributions of droplets are bimodal showing the peaks around $9{\mu}m$ and $20{\mu}m$ for every case. In comparison to background mineral particles, right shifting of size distribution line for NaCl particles was occurred. When NaCl solutions with three-step different concentrations were neulized, $W_L$ shows the strong droplet size dependence. It varied from $10.0mg\;m^{-3}$ up to $13.6mg\;m^{-3}$ with average $11.6mg\;m^{-3}$. A good relationship between $W_L$ and cloud droplet number concentration was obtained. Both chemical inhomogeneities (mixed components with mineral and C1) and homogeneities (only mineral components or C1) in individual droplet replicas were obviously observed from micro-PIXE elemental images.

• 터널과지하공간
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• 제13권4호
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• pp.245-259
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• 2003

Refering to the articles "Squeezing rocks in tunnels(Barla, 1995)" and "Tunnelling under squeezing rock conditions(Barla 2002)" this article deals with technologies for design, stability analysis and construction of the tunnel being driven in the squeezing rock mass. The definition of this type of behavior was proposed by ISRM(1994). The identification and quantification of squeezing is given according to both the empirical and semi-empirical methods available to anticipate the potential of squeezing problems in tunnelling. Based on the experiences and lessons learned in recent years, the state of the art in modem construction methods was reported, when dealing with squeezing rock masses by either conventional or mechanical excavation methods. The closed-form solutions available for the analysis of the rock mass response during tunnel excavation are described in terms of the ground characteristic line and with reference to some elasto-plastic models for the given rock mass. Finally numerical methods were used for the simulation of different models and for design analysis of complex excavation and support systems, including three-dimensional conditions in order to quantify the influence of the advancing tunnel face to the deformation behavior of the tunnel.

• 한국전산유체공학회지
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• 제12권2호
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• pp.26-31
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• 2007

A comparative study on the treatment of the turbulent heat flux with the elliptic blending second-moment closure for a natural convection flow is performed. Three cases of different treating the turbulent heat flux are considered. Those are the generalized gradient diffusion hypothesis (GGDH), the algebraic flux model (AFM) and the differential flux model (DFM). The constants in the models are adjusted with a primary emphasis placed on the accuracy of predicting the local Nusselt number. These models are implemented in a computer code specially designed for evaluation of turbulent models. Calculations are performed for a turbulent natural convection in the 1:5 rectangular cavity and the calculated results are compared with the available experimental data. The results show that the three models produce nearly the same accuracy of solutions. These results show that the GGDH, AFM and DFM models for treating the turbulent heat flux are sufficient for this simple shear flow where the shear production is dominant. It is observed that, in the weakly stratified region at the center zone of the cavity, the vertical velocity fluctuation is nearly zero in the GGDH solutions, which shows that the GGDH model may not be suitable for the strongly stratified flow. Thus, further study on the strongly stratified flow should be followed.

• Smart Structures and Systems
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• 제13권4호
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• pp.659-683
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• 2014

The static analysis of structures with arbitrary cross-section geometry and material lamination via a refined one-dimensional (1D) approach is presented in this paper. Higher-order 1D models with a variable order of expansion for the displacement field are developed on the basis of Carrera Unified Formulation (CUF). Classical Euler-Bernoulli and Timoshenko beam theories are obtained as particular cases of the first-order model. Numerical results of displacement, strain and stress are provided by using the finite element method (FEM) along the longitudinal direction for different configurations in excellent agreement with three-dimensional (3D) finite element solutions. In particular, a layered thin-walled cylinder is considered as first assessment with a laminated conventional cross-section. An atherosclerotic plaque is introduced as a typical structure with arbitrary cross-section geometry and studied for both the homogeneous and nonhomogeneous material cases through the 1D variable kinematic models. The analyses highlight limitations of classical beam theories and the importance of higher-order terms in accurately detecting in-plane cross-section deformation without introducing additional numerical problems. Comparisons with 3D finite element solutions prove that 1D CUF provides remarkable three-dimensional accuracy in the analysis of even short and nonhomogeneous structures with arbitrary geometry through a significant reduction in computational cost.

• 한국식품저장유통학회지
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• 제4권2호
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• pp.181-187
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• 1997

New HPLC method was developed for determination of some flavonoids such as naringin, hesperidin, neohesperidin, rutin, quercitrin, naringenin, hesperetin and apigenin and their contents in citrus juice and citrus peel from citrus varieties Brown in Cheju. Detection was at 280nm and reverse phase ${\mu}$-Bondapak C-18 column was used. Water/methanol/acetic acid as the mobile phase was better than water/acetonitrile/acetic acid. Flavonoids were more stable in 20% n,n-dimethylformamide in methanol(20% DMF) than methanol and pH 12 adjusted by 1N-sodium hydroxide solution. Standard flavonoid solutions were injected three times consecutively and the reproduciability was 0.236 to 3.550%, Correlation coefficient of the calibration curve was 0.9946 to 0.9999. The exiraction efficiency of hesperidin from citrus peel was evaluated with different extraction method such as reflux, ultra-sonicating method, using three solvents (aqueous solutions with pH12 adjusted by 1N-sodium hydroxide, methanol and 20% DMF), respectively. The reflux for 4 hour in 20% DMF was the most efficient of the tested methods and solvents, and recovery percentage were 78.0∼130.0%. Flavonoids were determined in citrus juice. Naringin was 68.2mg/100$m\ell$ in Natsudaidai, Hesperidin were 85.6mg/100$m\ell$ in Sankyool and Neohesperidin was 25.3mg/100$m\ell$ in Dangyooja. Flavonoids were determined in citrus peel. Naringin was 110mg/g in Dangyooja, Hesperidin was 242mg/g in Hungjin and Neohesperidin was 87.9mg/g in Dangyooja.

• The Journal of Asian Finance, Economics and Business
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• 제8권2호
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• pp.1225-1235
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• 2021

This study aims to analyze the influence of farmer characteristics, Ihsan attitude, economic conditions, and socio-cultural environmental support, and the number of family members on farmer behavior in meeting food needs in realizing household food security, with the role of the government as a moderator. This study is about the relationship between farmer behavior and their household food security. This research uses a quantitative research method involving 337 farmers from three villages located in three different sub-districts, namely Alang-alang village, Tragah sub-district, Mrecah village, Tanah Merah sub-district, and finally Gangsean village, Sepulu sub-district. The quantitative analysis approach consists of formulating problems, compiling models, obtaining data, finding solutions, testing solutions, analyzing results, and interpreting results. From the 7 hypotheses that were built, it was identified that there was 1 hypothesis that was not significant, namely the influence of the support of the socio-cultural environment on farmer behavior to meet the food needs of farmers' households. The attitude that is identified is still very rarely used in the context of agricultural human resources and at the same time is an inherent character of Madurese farmers which is an interesting part for researchers to study more deeply and become new or authentic in this research.

• Nuclear Engineering and Technology
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• 제18권3호
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• pp.228-237
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• 1986

본 논문은 Fuzzy관련공식의 역문제에 대한 해석방법론의 비교연구를 제시하고 있다. 여기서 Fuzzy 집합은 완전한 Brouwerian격자에의 투영으로 정의된다. 현재까지 관련공식의 역해석은 세가지 다른 결과로 연구되고 있어, 이를 이용하여 원자력발전소 주급수펌프의 고장진단에 적용하여 검토하였다.