• Title/Summary/Keyword: double-shell

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Intensive Monitoring Survey of Nearby Galaxies (IMSNG) : Constraints on the progenitor system of a normal Type Ia SN 2019ein from its light curve at the early phase

  • Lim, Gu;Im, Myungshin;Kim, Dohyeong;Paek, Gregory S.H;Choi, Changsu;Kim, Sophia;Hwang, Sungyong
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.1
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    • pp.55.2-56
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    • 2021
  • The progenitor of Type Ia supernovae (SNe Ia) is mainly believed to be a close binary system of acarbon-oxygen white dwarf (CO WD) and non-degenerate companion (single degenerate) or another WD (double degenerate). However, it is unclear which system is more prevalent. Here, we present a high cadence optical/Near-IR light curve of normal but slightly faint type Ia SN 2019ein from IMSNG project. We fit the early light curve (t <+8.3 days from the first detection) with various models to find the shock-heated cooling emission from SN ejecta-companion interaction. No significant shock-heated cooling emission is found, from which we constrain the progenitor star size as the following. The upper limit (Rupper,*) of the companion size in R-band is ~0.2R when forcing the first light time (tfl) to have one value and ~0.9R when using the mean value of tfl from the fitting in each band. Assuming the source of the I-band curve is almost powered from the radioactive decay, we obtained Rupper,*~1.2R. The early B-V color curve is in agreement with the model color curve of the 2M main sequence companion. These results allow us to at least rule out large stars like red giants as a companion star of the binary progenitor system of this supernova. B-R and V-R color do not show any significant signs of a red bump, which shows a thin helium shell (MHe<0.1M) for the sub-Mch WD (double detonation model). In addition, we estimated the distance to NGC 5353 as 37.098±0.028Mpc.

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The Studies on Hydrolysis of the Silk Fibroin by Proteolytie Enzyme, Bombyx mori II. Relation between the Fibroin Hydrolysis of Different Cocoon Layers and Physical Property of Silk Fiber (견 Fibroin의 효소분해에 관한 연구 II-견층부위별 Fibroin 분해율 차이와 견사물성과의 관계-)

  • 이용우;최병희;송기언;남중희
    • Journal of Sericultural and Entomological Science
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    • v.18 no.1
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    • pp.21-26
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    • 1976
  • The study was carried out to investigate the variations in the fibroin hydrolysis of different cocoon shell layers, and the relationship between the hydrolysis and silk physical property. The obtained results are as follows: 1. The fibroin hydrolyzing ratio was highest at the inner layer of cocoon shell and. next in order. at the middle layer and at the outer layer. 2. The fibroin hydrolyzing ratio of abnormal cocoons was higher than normal cocoon and it was different among them, tile highest was double coroon, thin shell cocoon and perforated cocoon in order. 3. The sericin content and fibroin hydrolyzing ratio of Jam 111 and Jam 112 was higher than that of Jam 111 $\times$ Jam 112. 4. The fibroin hydroiyzing ratio of the cocoons fed with the artificial diets was increased at the inner layer. The sericin content of those lessened at the inner layer, however, it slightly increased at the most inner layer more than at the inner layer. 5. The breaking strength of the degummed silk fiber of different cocoon layers was reduced at the inner layer. The breaking Strength of abnormal silk fiber was less than that of normal silk fiber. 6. A negative correlation (r= -0.8) )was approved between fibroin hydrolyzing ratio and breaking strength of silk fiber, and the regression line was Y=-0.29x+5.07.

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Hydrotreating for Stabilization of Bio-oil Mixture over Ni-based Bimetallic Catalysts (Ni계 이원금속 촉매에 의한 혼합 바이오오일의 안정화를 위한 수소첨가 반응)

  • Lee, Seong Chan;Zuo, Hao;Woo, Hee Chul
    • Clean Technology
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    • v.27 no.1
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    • pp.69-78
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    • 2021
  • Vegetable oils, such as palm oil and cashew nut shell liquid (CNSL), are used as major raw materials for bio-diesel in transportation and bio-heavy oil in power generation in South Korea. However, due to the high unsaturation degree caused by hydrocarbon double bonds and a high content of oxygen originating from the presence of carboxylic acid, the range of applications as fuel oil is limited. In this study, hydrotreating to saturate unsaturated hydrocarbons and remove oxygen in mixed bio-oil containing 1/1 v/v% palm oil and CNSL on monometallic catalysts (Ni and Cu) and bimetallic catalysts (Ni-Zn, Ni-Fe, Ni-Cu Ni-Co, Ni-Pd, and Ni-Pt) was perform under mild conditions (T = 250 ~ 400 ℃, P = 5 ~ 80 bar and LHSV = 1 h-1). The addition of noble metals and transition metals to Ni showed synergistic effects to improve both hydrogenation (HYD) and hydrodeoxygenation (HDO) activities. The most promising catalyst was Ni-Cu/��-Al2O3, and in the wide range of the Ni/Cu atomic ratio of 9/1~1/4, the conversion for HYD and HDO reactions of the catalysts were 90-93% and 95-99%, respectively. The tendency to exhibit almost constant reaction activity in these catalysts of different Ni/Cu atomic ratios implies a typical structure-insensitive reaction. The refined bio-oil produced by hydrotreating (HDY and HDO) had significantly lower iodine value, acid value, and kinetic viscosity than the raw bio-oil and the higher heating value (HHV) was increased by about 10%.

Optimization of the Path of Inner Reinforcement for an Automobile Hood Using Design Sensitivity Analysis (설계민감도해석을 이용한 자동차후드 보강경로 최적설계)

  • Lee, Tae-Hui;Lee, Dong-Gi;Gu, Ja-Gyeom;Han, Seok-Yeong;Im, Jang-Geun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.1 s.173
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    • pp.62-68
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    • 2000
  • Optimization technique to find a path of an inner reinforcement of an automobile hood is proposed by using design sensitivity informations. The strength and modal characteristics of the automobile hood are analyzed and their design sensitivity analyses with respect to the thickness are carried out using MSC/NASTRAN. Based on the design sensitivity analysis, determination of design variables and response functions is discussed. Techniques improving design from design sensitivity informations are suggested and the double-layer method is newly proposed to optimize the path of stiffener for a shell structure, Using the suggested method, we redesign a new inner reinforcement of an automobile hood and compare the responses with the original design. It is confirmed that new design improved in the frequency responses without the weight increasement.

The study of the $BiO_{6}$ octahedra structure in superconducting $Ba_{0.6}K_{0.4}BiO_3$ single crystal by extended x-ray absorption spectroscopy (EXAFS에 의한 $Ba_{0.6}K_{0.4}BiO_3$ 단결정의 초전도 상태에서 $BiO_{6}$ octahedra 구조의 연구)

  • 김봉준;김영철;김현탁;강광용;이재민
    • Progress in Superconductivity
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    • v.4 no.2
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    • pp.148-152
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    • 2003
  • We have observed the temperature dependences of Bi $L_{III}$ edge spectra by extended X-ray absorption spectroscopy for a high quality single crystal and a powder of the $Ba_{0.6}K_{0.4}BiO_3$ superconductor. $Ba_{0.6}K_{0.4}BiO_3$ has the cubic structure and metallic states. The deformation of the $BiO_{6}$ octahedra, which is due to the anomalies of the Bi-O and Bi-Ba bond length, was showed by the double-shell fit. It was clearly found that these anomalies are owing to the difference in the strength of Bi-O bonds. The temperature dependences of both bond lengths and the Debye-Walter factor ${\sigma}^2$ of the Bi-O and Bi-(Ba,K) bond are discussed to illustrate local structural features of the $Ba_{0.6}K_{0.4}BiO_3$

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Structural performance of cold-formed steel column bases with bolted moment connections

  • Chung, K.F.;Yu, W.K.;Wang, A.J.
    • Steel and Composite Structures
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    • v.5 no.4
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    • pp.325-340
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    • 2005
  • This paper presents a thorough investigation into the structural performance of cold-formed steel column bases using double lipped C sections with bolted moment connections. A total of four column base tests with different connection configurations were carried out, and it was found that section failure under combined bending and shear was always critical. Moreover, the proposed column bases were demonstrated to be structurally efficient attaining moment resistances close to those of the connected sections. In order to examine the structural behaviour of the column base connections, a finite element model was established using shell and spring elements to model the sections and the bolted fastenings respectively. Both material and geometrical non-linearities were incorporated, and comparison between the test and the numerical results was presented in details. The design rules originally developed for bolted moment connections between lapped Z sections were adopted and re-formulated for the design of column base connections after careful calibration against the test data. Comparison on co-existing moments and shear forces at the critical cross-sections of the column bases was fully presented. It was shown that the proposed design and analysis method was structurally adequate to predict the failure loads under combined bending and shear for column bases with similar connection configurations.

Structural performance of cold-formed steel column bases with bolted moment connections

  • Chung, K.F.;Yu, W.K.;Wang, A.J.
    • Steel and Composite Structures
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    • v.5 no.4
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    • pp.289-304
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    • 2005
  • This paper presents a thorough investigation into the structural performance of cold-formed steel column bases using double lipped C sections with bolted moment connections. A total of four column base tests with different connection configurations were carried out, and it was found that section failure under combined bending and shear was always critical. Moreover, the proposed column bases were demonstrated to be structurally efficient attaining moment resistances close to those of the connected sections. In order to examine the structural behaviour of the column base connections, a finite element model was established using shell and spring elements to model the sections and the bolted fastenings respectively. Both material and geometrical non-linearities were incorporated, and comparison between the test and the numerical results was presented in details. The design rules originally developed for bolted moment connections between lapped Z sections were adopted and re-formulated for the design of column base connections after careful calibration against the test data. Comparison on co-existing moments and shear forces at the critical cross-sections of the column bases was fully presented. It was shown that the proposed design and analysis method was structurally adequate to predict the failure loads under combined bending and shear for column bases with similar connection configurations.

A Study on the Contact Stress Analysis for X-ring (X-ring의 접촉 응력 해석에 관한 연구)

  • Lee, Hyun-Seung;Lee, Young-Shin;Lee, Jung-Hyun;Chun, Byong-Sun;Baek, Joon-Ho;Kim, Suk-Yoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.9
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    • pp.733-739
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    • 2008
  • The X-ring is a elastomer with X-shaped cross-section used as a mechanical seal or gasket. Such a X-ring was equipped in a groove and compressed between two or more parts, acts as a seal on the interface. This study aims to detect contact stress and deformed shape of a X-shaped ring shell under various compressive contact conditions. A contact stress analysis was carried out by finite element analysis. The effect of compression rates and thickness design variable was analyzed. X-ring kept up the double seal until a compression rate of 20%. The maximum stresses of the X-ring was occurred at the top and bottom corner. The maximum contact stress of X-ring was rapidly increased according with the compression rate. The X-rings with thickness design variable from 1.3 mm to 1.5 mm had comparative low stress levels.

Undamped Dynamic Response of Anisotropic Laminated Composite Plates and Shell Structures using a Higher-order Shear Deformation Theory (비등방성 복합적층판 및 쉘의 고차전단변형을 고려한 비감쇄 동적응답)

  • Yoon, Seok Ho;Han, Seong Cheon;Chang, Suk Yoon
    • Journal of Korean Society of Steel Construction
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    • v.9 no.3 s.32
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    • pp.333-340
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    • 1997
  • This paper will expand the third-order shear deformation theory by the double-Fourier series and reduce to the solution of a system of ordinary differential equations in time, which are integrated numerically using Newmark's direct integration method and clarify the undamped dynamic responses for the cross-ply and antisymmetric angle-ply laminated composite plates and shells with simply supported boundary condition. Numerical results for deflections are presented showing the effect of side-to-thickness ratio, aspect ratio, material anisotropy, and lamination scheme.

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Spectroscopic Study of the Planetary Nebula NGC 6210: Velocity Structure and Permitted Lines

  • Lee, Seong-Jae;Wi, Jin-Kyung;Hyung, Siek
    • Journal of the Korean earth science society
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    • v.30 no.5
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    • pp.611-621
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    • 2009
  • Using the spectroscopic data secured with the Hamilton Echelle Spectrograph at Lick Observatory, we found the physical condition of the planetary Nebula NGC 6210. The spectral line profiles of the permitted and forbidden lines have been analyzed using IRAF and StarLink/Dipso. The hydrogen number densities ($N_H$) are 2,000-20,000 $cm^{-3}$, and the electron temperatures are 8,100-10,300 K based on the forbidden lines. The expansion velocities, derived from the Full Width at Half Maximum (FWHM) and the double peak of the line profiles, are in the range of 10 to $45\;kms^{-1}$. The expansion velocities imply a shell structure with an accelerated nebular gas. We also derived abundances from the permitted lines of CII, CIII, NII, NIII, OII, and OIII, which may have been formed through the fluorescence mechanism. NGC 6210 is likely to be evolved from a progenitor of more than $3M_{\bullet}$, which had been born near the Galactic plane.