• 제목/요약/키워드: atomic spin

검색결과 161건 처리시간 0.023초

Derivation of Cubic and Hexagonal Mesoporous Silica Films by Spin-coating

  • Pan, Jia-Hong;Lee, Wan-In
    • Bulletin of the Korean Chemical Society
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    • 제26권3호
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    • pp.418-422
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    • 2005
  • By introducing spin-coating method to the evaporation induced self-assembly (EISA) process, a simple and reproducible route in controlling the mesophase of silica thin films has been developed for the first time in this work. When a comparatively solvent-rich Si-sol (The atomic ratio of TEOS : F127 : HCl : $H_2O$ : EtOH = 1 : 0.006 : 0.2 : 9.2 : 30) was used as coating solution, the mesophase of resultant silica films was selectively controlled by adjusting the spin-on speed. The cubic mesophase has been obtained from the coating at a low rpm, such as 600 rpm, while the 2-D hexagonal mesophase is formed at a high rpm, such as 2,500 rpm. At a medium coating speed, a mixture of cubic and hexagonal mesophase has been found in the fabricated films. The present results confirm that the evaporation rate of volatile components at initial step is critical for the determination of mesopore structures during the EISA process.

The Technology Licensing Office as Factor of Success for Spin-off: Case Study of a Research Lab Startup of Korea

  • Ham, Hyeong-Uk;Ko, Chang-Ryong
    • Asian Journal of Innovation and Policy
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    • 제5권2호
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    • pp.129-145
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    • 2016
  • This is a case study to analyze the role of technology licensing or transfer office (TLO) as factors of success for the spin-off from government research lab. The case company is a research lab startup, which is a joint venture through technology investment by a government research lab or university in the designated R&D parks and cash investment by the partner company. The case company listed on the stock market in 2015 reaching a market capitalization of US$ 1.2 billion. We confirm the success factors of startups pointed out in many studies: original technology, good understanding of core technology and production technology, technological competitiveness in the market. However, there is an important factor not well discussed in the previous studies, the role of TLO. TLO guided the company ownership, management, technology, and solved problems that pause business itself. The case became the sample of research lab startup and technology investment in Korea.

AB INITIO CALCULATIONS OF STRONGLY CORRELATED ELECTRONS: ANTIFERROMAGNETIC GROUND STATE OF $UO_2$

  • YUN YOUNSUK;KIM HANCHUL;KIM HEEMOON;PARK KWANGHEON
    • Nuclear Engineering and Technology
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    • 제37권3호
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    • pp.293-298
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    • 2005
  • We have performed the density functional theory calculations of $UO_2$ using the spin-polarized generalized gradient approximation (SP-GGA) and the SP-GGA+U approach. The SP-GGA+U approach correctly predicts the insulating electronic structure with antiferromagnetic ordering, but the SP-GGA calculations predict metallic behavior. The cohesive properties obtained from the SP-GGA+U calculations are in good agreement with the available experimental results and previous calculations. The spin-polarized local density of states shows that the antiferromagnetic ordering of $UO_2$ is governed by 5f orbitals of uranium ion. Our calculations demonstrate that the strong correlation of U 5f electrons should be taken into account for a reliable description of $UO_2$ physics.

단백질 칩 기판의 표면 스크래칭 효과 (Effects of Scratching on the Surface of Protein Chip Plates)

  • 현준원;황정일
    • 한국표면공학회지
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    • 제40권2호
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    • pp.98-102
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    • 2007
  • [ $NiCl_2$ ] and poly-L-lysine coated protein chip plates have been fabricated using a spin coating system. Water has been used as solvent and scratching effects on glass slides and ITO have been investigated. We also observed the surface properties of $NiCl_2$ and poly-L-lysine coated slides by using PSA(Particle size analyzer) and AFM(Atomic force microscope). The AFM results imply that the surface patterns created in the spin coating system determine the protein adsorption. Adsorption of histidine-tagged KRS proteins immobilized on glass slides and ITO was analyzed using a BAS image system. The results suggest that the scratching effect was increased ability of protein adsorption.

Correlation between Structures and Magnetism in Iron: Ferromagnetism and Antiferromagnetism

  • Lee, Dong-Kook;Hong, Soon-Cheol
    • Journal of Magnetics
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    • 제12권2호
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    • pp.68-71
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    • 2007
  • Even a pure bulk Fe has a complicated magnetic phase and its magnetism is still needed to be clarified. In this study we investigated the magnetism of bcc and fcc bulk Fe with total energy calculations as functions of atomic volume. The full-potential linearized augmented plane wave method was adopted within a generalized gradient approximation. The ground state of bulk Fe is confirmed to be of ferromagnetic (FM) bcc. For fcc structured Fe an antiferromagnetic (AFM) state is more stable compared to FM states which exist as low spin and high spin states. The stable AFM states were found to accompany a tetragonal distortion, while the FM states remained in a cubic symmetry. At an expanded lattice constant a high spin FM state was calculated to be able to be stabilized with significant enhanced magnetic moment compared to the value of the ground state, bcc FM.

Fabrication of Poly(diallyldimethylammonium chloride) - Patterned Substrates for Patterning of Single Strand DNA Using Ion Implantation

  • Ahn, Mi-Young;Hwang, In-Tae;Jung, Chan-Hee;Choi, Jae-Hak;Nho, Young-Chang
    • 방사선산업학회지
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    • 제5권3호
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    • pp.243-247
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    • 2011
  • In this study, a convenient method for the selective immobilization of single strand DNA (ssDNA) on a polymer surface was described. A positively charged polyelectrolyte, poly(diallyldimethylammonium chloride) (PDDA), was spin-coated on a tissue culture petridish and the micropatterns of the PDDA were formed by selective ion implantation through a pattern mask. The surface property of the implanted PDDA was investigated by using a surface profiler and FT-IR spectrometer. Cy3-labeled ssDNA was selectively immobilized on the PDDA patterns through ionic interaction and thus, well-defined ssDNA patterns were obtained.

Dynamics of a Bose-Einstein Condensate on Changing Speeds of an Atomchip Trap Potential

  • Kim, Seung Jin;Noh, Jae June;Kim, Min Seok;Lee, Jin Seung;Yu, Hoon;Kim, Jung Bog
    • Journal of the Optical Society of Korea
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    • 제18권6호
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    • pp.633-638
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    • 2014
  • We report experimental behaviors of condensed $^{87}Rb$ atoms responding to changes in the trap potential of the atomchip. The two-types of adiabatic and non-adiabatic overall changes were implemented by changing the ramp-down speed of the chip-wire current, which can dominantly modify the one-axis magnetic field gradient. Under the adiabatic process, a pure condensate stayed in the initial spin state and collectively oscillated with both monopole and dipole modes, while an atomic cloud above the critical temperature exhibited sound waves in a dense ultracold gas. On the other hand, Bose-Einstein condensate atoms with non-adiabatic perturbation were split into spatially different positions by spin states through spin-flip. We investigated the split ratio among spin states depending on final evaporation frequency. Potential changes, of course, cause collective oscillations regardless of the changing process.

Protein Adsorption on the Nickel-coated Glass Slide for Protein Chips

  • Hyun, June-Won;Kim, Shi-Yong;Lee, Sang-Hee;Park, Heon-Yong;Pyee, Jae-Ho;Kim, Sung-Hoon
    • Bulletin of the Korean Chemical Society
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    • 제23권12호
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    • pp.1724-1728
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    • 2002
  • The adsorption of proteins on the surface of glass slides is essential for the construction of protein chips. Here, we report that a Histidine (His)-tagged protein protein has been efficiently adsorbed on glass coated with nickel. A variety of nickel chloride-coated plates were prepared by the spin-coating method and adsorbed to the His-tagged protein. When the protein was adsorbed onto the surface of a variety of nickel chloride-coated glass slides, the efficiency of protein adsorption was dependent upon the coating conditions such as nickel chloride concentration, the spin speed and the drying temperature. The slides appropriate for protein adsorption were obtained when the slides were coated with 11%(w/w) of $NiCl_2$ at the spin speed of 4000 rpm for 20 sec and then dried at higher than 40°C. The physical properties of their nickel chloride thin layer were characterized by scanning electron microscopy. x-ray diffraction and atomic force microscopy, finding that the nickel chloride particles were around 10 nm in diameter and uniformly crystallized at 101 faces. These results show that nickel chloride-coated slides prepared by the spin-coating method are utilizable for the construction of Histagged protein chips.

Cu 3d 와 4p 궤도함수의 혼성과 리간드의 Spin-Orbit Coupling 이 Tetragonally 일그러진 $CuCl_4^{2-}$ 착물의 Zero-Field Splitting에 미치는 영향 (The Effect of Ligand's Spin-Orbit Coupling and the Intermixing of │3d 〉 and │4p 〉 Cu Atomic Orbitals on Zero-Field Splitting in the Tetragonally Distorted Tetrahedral $CuCl_4^{2-}\;Complex^\ast$)

  • 이왕노;최우성;백우현;김동희;최창진;이기계
    • 대한화학회지
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    • 제34권1호
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    • pp.37-43
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    • 1990
  • $D_{2d}$ 점군에 속하는 강결정장의 tetragonally 일그러진 사면체 3$d^9$전자계 착물의 바닥상태에 대한 리간드 궤도함수의 spin-orbit coupling과 중심 금속의 3d와 4p궤도함수의 intermixing이 미치는 영향에 대하여 중첩 섭동론을 사용하여 연구하였다. 단결정 $Cs_2CuCl_4$의 tetragonally 일그러진 $CuCl_4^{2-}$에 대한 d-d전이의 실험값을 사용한 LCAO-MO분석은 구리이온과 리간드 사이의 공유결합성은 Cu 4p orbital의 기여가 증가하므로서 급격히 감소하고 리간드 Cl 3p궤도함수의 spin-orbit coupling 상호작용에 의한 바닥상태의 에너지 준위 분리에 대한 효과는 $\Gamma_7(E)\;\to\;\Gamma_6(E)\; >\;\Gamma_7(B_2)\;\to\;\Gamma_6(E)\; >\;\Gamma_7(B_2)\;\to\;\Gamma_7(E)$의 순서로 감소하였다.

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물리적인 방법(PSL, TL, ESR)을 이용한 방사선 조사 건조과일의 검지 특성 (Detection Properties of Irradiated Dried Fruits by Using Photo-stimulated Luminescence, Thermoluminescence, and Electronspin Resonance Methods)

  • 윤영민;박재남;최수정;박종흠;김재경;변의백;이주운;한인준;박진규;김재훈;송범석
    • 방사선산업학회지
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    • 제8권1호
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    • pp.11-15
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    • 2014
  • In this study, we investigated the applicability of the photostimulated luminescence (PSL), thermoluminescence (TL) and electron spin resonance (ESR) methods for freeze dried fruits which are not allowed to be irradiated in Korea. Apples and persimmons samples that had been dried with a freeze drier were irradiated at a dose of 1, 3, 5, 7, and 10 kGy, using a gamma radiator with a cobalt-60 source. With the PSL method, the dried apples showed photon counts of less then 700 counts/60 s (negative) in all the samples, whereas the dried persimmons that were gamma-irradiated above 3 kGy yielded photon counts of between 700 and 5,000 counts/60 s (intermediate). The TL results showed that this technique is useful for detecting irradiated samples; the TL ratios ($TL_1/TL_2$) measured for the food samples at an irradiation dose of 1 kGy were 0.13 for dried apples and 0.79 for dried persimmons. With regard to the results of ESR spectroscopy, the strength of the ESR signals from the dried fruits increased linearly in a dosedependent manner. However, the characteristic signal was not found in all the samples. In conclusion, the TL methods only can be used for the detection of gamma-irradiated dried apples and persimmons.