• 제목/요약/키워드: High-spin

검색결과 752건 처리시간 0.031초

Analysis of Spin Valve Tunneling Magnetoresistance Sensor for Eddy Current Nondestructive Testing

  • Kim, Dong-Young;Yoon, Seok-Soo;Lee, Sang-Hun
    • 비파괴검사학회지
    • /
    • 제28권6호
    • /
    • pp.524-530
    • /
    • 2008
  • The spin valve tunneling magnetoresistance (SV-TMR) sensor performance is analyzed using Stoner-Wohlfarth model for the detection of eddy current signals in nondestructive testing applications. The SV-TMR response in terms of the applied AC magnetic field dominantly generates the second harmonic amplitude in hard axis direction. The second harmonic eddy current signal detection using SV-TMR sensor shows higher performance than that of the coil sensor at lower frequencies. The SV-TMR sensor with high sensitivity gives a good solution to improve the low frequency performance in comparison with the inductive coil sensors. Therefore, the low frequency eddy current techniques based on SV-TMR sensors are specially useful in the detection of hidden defects, and it can be applied to detect the deeply embedded flaws or discontinuities in the conductive materials.

m-Phenylene-Linked Bis-(Biradicals). Generation, Characterization and Computational Studies

  • Nicolaides, Athanassios;Tomioka, Hideo
    • Journal of Photoscience
    • /
    • 제10권1호
    • /
    • pp.165-173
    • /
    • 2003
  • m-Phenylene-linked biscarbenes, bisnitrenes and carbenonitrenes can be formed photochemically from appropriate nitrogenous precursors. Generation of such reactive intermediates under matrix-isolation conditions allows for their characterization by spectroscopic techniques such as ESR, UV /vis and IR. The latter method is also useful in characterizing secondary products derived from these reactive intermediates. Computational chemistry methods complement experimental IR data, aiding, thus, in identification of such compounds. In addition electronic structure calculations help in developing qualitative and semi-quantitative models, which can be useful in predicting ground-state multiplicities. The parent systems of m-phenylene-linked carbenes and nitrenes have high-spin ground states, but a switching to lower multiplicity can be achieved by chemical substitution. The ground state and various low-lying excited states of m-phenylenecarbenonitrenes can be reasonably approximated by simple valence-bond depictions. Finally, m-phenylenecarbenonitrenes are photoreactive in the inert matrix isomerizing to cyclopropene derivatives.

  • PDF

Nanoscale-NMR with Nitrogen Vacancy center spins in diamond

  • Lee, Junghyun
    • 한국자기공명학회논문지
    • /
    • 제24권2호
    • /
    • pp.59-65
    • /
    • 2020
  • Nitrogen-Vacancy (NV) center in diamond has been an emerging versatile tool for quantum sensing applications. Amongst various applications, nano-scale nuclear magnetic resonance (NMR) using a single or ensemble NV centers has demonstrated promising results, opening possibility of a single molecule NMR for its chemical structural studies or multi-nuclear spin spectroscopy for quantum information science. However, there is a key challenge, which limited the spectral resolution of NMR detection using NV centers; the interrogation duration for NV-NMR detection technique has been limited by the NV sensor spin lifetime (T1 ~ 3ms), which is orders of magnitude shorter than the coherence times of nuclear spins in bulk liquid samples (T2 ~ 1s) or intrinsic 13C nuclear spins in diamond. Recent studies have shown that quantum memory technique or synchronized readout detection technique can further narrow down the spectral linewidth of NMR signal. In this short review paper, we overview basic concepts of nanoscale NMR using NV centers, and introduce further developments in high spectral resolution NV NMR studies.

Synthesis and characterization of new liquid crystalline polymer for in-cell retardation film

  • Wang, Lei;Lim, Yeong-Jin;Kang, Hoon;Choi, Min-Oh;Lee, Seung-Hee;Lee, Myong-Hoon
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
    • /
    • pp.1409-1411
    • /
    • 2006
  • A new rod-like liquid crystalline monomer having divinyl terminal groups was synthesized and polymerized by using thiol-ene UV polymerization technique. High quality thin film with good retardation value was prepared on a rubbed alignment layer without the inert gas purging. The retardation value of the resulting film was controlled by experimental conditions such as spin speed, concentration, and spin time. From the retardation value and thickness measurement, ${\bigtriangleup}n$ was calculated to be 0.169 for the resulting film having thickness of 815.1 nm.

  • PDF

STRUCTURAL MORPHOLOGY AND DIELECTRIC PROPERTIES OF POLYANILINE-EMERALDINE BASE AND POLY METHYL METHACRYLATE THIN FILMS PREPARED BY SPIN COATING METHOD

  • Shekar, B. Chandar;Yeon, Ji;Rhee, Shi-Woo
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
    • /
    • pp.1081-1084
    • /
    • 2003
  • Structural morphology, annealing behavior and dielectric properties of polyaniline-emeraldine base (Pani-EB) and poly methyl methacrylate (PMMA) thin films prepared by spin coating technique have been studied. MIM and MISM structures were used to investigate annealing and dielectric behavior. The XRD and AFM spectrum of as grown and annealed thin films indicates the amorphous nature. The observed amorphous phase, low loss, dielectric behavior and thermal stability even at high temperatures implies the feasibility of utilizing PMMA and Pani-EB thin films as gate dielectric insulator layer in organic thin film transistors which can find application in flat panel display.

  • PDF

졸겔 스핀 코팅에서 질산촉매가 티탄산연 박막의 물성에 미치는 영향 (The Effect of Nitric Acid Catalyst on the Properties of Lead Titanate Thin Films by Sol Gel Spin Coating)

  • 이전국;정형진;김종희
    • 한국세라믹학회지
    • /
    • 제28권11호
    • /
    • pp.859-864
    • /
    • 1991
  • High quality lead titanate thin films were fabricated by spin coating on a silicon substrate. The resulting dried gel layers were uniform in thickness through 2$\times$2 $\textrm{cm}^2$ area, and polycrystalline perovskite structures developed almost crack free with a heat treatment above 50$0^{\circ}C$ in films with thickness above 360 nm. Metastable pyrochlore structures were observed in films with thickness of 160 nm when heat treated at 500 and $600^{\circ}C$, but these structure did not appear in films with thickness of 360 nm. The thickness dependence in crystal structure of films was studied. by varying the substrate condition and analyzing the interface between the film and substrate. In native oxide films on silicon stbstrates, amorphous dried gel layers were heterogeneously nucleated. Metastable cubic pyrochlore structure could be crystallized in amorphous native oxide.

  • PDF

주형온도가 CP Ti의 주조성에 미치는 영향 (Influence of the Mold Temperature on the Castability of CP Ti)

  • 정종현;주규지;고은경
    • 대한치과기공학회지
    • /
    • 제28권1호
    • /
    • pp.9-17
    • /
    • 2006
  • The purpose of this study was to evaluate the titanium castability with a spin type casting machine(TiCast, Super R, Selec, Osaka. Japan). We tested phosphate bonded investment "Rematitan$^{(R)}$Plus(Dentaurum, Inc., Pforzheim, Germany)"of mesh grid pattern and plate pattern. Four different mold temperatures(room temperature, 200$^{\circ}C$, 400$^{\circ}C$ and 600$^{\circ}C$) were prepared for the present study. In mesh grid pattern with spruing of $\varphi$0.88㎜ dimeter, when the mold temperature increased, high percentage of castability was gained. Mold temperature showed a highly significant(p<0.05) correlation on the castability, In plate pattern, the higher the mold temperature during casting, the greater the adhesive phenomenon between Ti surface and the investment.

  • PDF