133 research outputs found
Micromachined High-Aspect-Ratio Parylene Spring and Its Application to Low-Frequency Accelerometers
A new microfabrication technology for high-aspect-ratio parylene structure has been developed for soft spring applications. Free-standing parylene beams with widths of 10â40 ”m and aspect ratios of 10â20 have been successfully fabricated. Since parylene has a small Young's modulus, a high-aspect-ratio beam with a spring constant of the order of 1 Ă 10^(-3) N/m has been realized. The large yield strain of parylene enables a test structure to have a large-amplitude oscillation of 600 ”m_(p-p), without any failure of the high-aspect-ratio springs. An early prototype of in-plane capacitive accelerometer was also developed. It was found that its resonant frequency is as low as 37 Hz, and the noise spectral density is 64 ”g/(Hz)^(0.5)
Micromachined high-aspect-ratio parylene beam and its application to low-frequency seismometer
A new microfabrication technology for high-aspect-ratio Parylene structure is developed for soft spring applications and applied to in-plane seismometer which covers low frequency (<1 Hz) and small acceleration range. Parylene beams having 10-40 /spl mu/m wide and an aspect ratio of 10-30 were successfully fabricated. Since Parylene has a small Young's modulus and is non-brittle material, high-aspect-ratio robust beam having spring constant on the order of 1 x 10^(-3) N/m was realized. A prototype capacitive seismometer was also made, and its resonant frequency and noise spectral density was respectively measured to be 37 Hz and 45 ”g / âHz Since the Brownian noise is only 25 ng ”g / âHz, seismometer having much lower noise floor may be feasible using this new technology
Purification, identification and phosphorylation of annexin I from rat liver mitochondria.
Annexin was purified from rat liver mitochondria to an apparent homogeneity with a molecular weight of 35 kDa as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified mitochondrial annexin (AXmito) was identified as annexin I by an immunoblot analysis using anti-annexin I antibody. The inhibitory effect of AXmito I on porcine pancreatic phospholipase A2 activity was as potent as that of bovine lung annexin I. The presence of annexin I in mitochondria was confirmed by an electron-microscopic study. AXmito I was shown to be phosphorylated by intrinsic protein tyrosine kinases on its tyrosine residues. This annexin was also phosphorylated by protein kinase C.</p
Symmetry-adapted HAM/3 method and its application to some symmetric molecules
The semiempirical HAM/3 method developed by Lindholm and coworkers about two decades ago has been known to have a deficiency that splits energies for the degenerate energy states. We have recently proposed a group-theoretical approach to remedy the internally broken symmetry of the HAM/3 Hamiltonians. In this paper, we present some results of its application to various small molecules with symmetry Td, C3v, and D3h. The proposed scheme gives correct degeneracy for these molecules.O mĂ©todo semi-empĂrico HAM/3, desenvolvido por Lindholm e colaboradores hĂĄ mais de duas dĂ©cadas, tem uma deficiĂȘncia. As energias de excitação calculadas por HAM/3 para estados degenerados sĂŁo desdobradas. Recentemente foi proposto um mĂ©todo para corrigir esta deficiĂȘncia. Apresentamos aqui resultados de aplicaçÔes deste novo mĂ©todo para algumas molĂ©culas com simetria Td, C3v e D3h. O esquema proposto apresenta a degenerescĂȘncia correta para as molĂ©culas estudadas.445449Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP
Creep-Fatigue Evaluation Methodologies and Related Issues for Japan Sodium Cooled Fast Reactor (JSFR)
AbstractThis paper describes the main topics on creep-fatigue evaluation methodologies for the Japan Sodium Cooled Fast Reactor (JSFR). JSFR's operating temperature is 550C and design life is 60 years with key technologies in terms of creep-fatigue being the adoption of new materials, 316FR and Mod.9Cr-1Mo steel, and the development of evaluation methodologies for those materials: 316FR is low-carbon nitrogen-added 316 steel which has superior creep properties and will be used for the reactor vessel and internal structures. Mod.9Cr-1Mo steel will be applied to most of the coolant systems including primary piping, intermediate heat exchangers, secondary piping and steam generators. Creep-fatigue evaluation methodologies for those materials are being developed concentrating on capturing long-term materials behavior and strength so that the evaluation of 60-year design is justified, and simplified evaluation methods for strain ranges and stress relaxation behaviors applicable to JSFR structures which have various configurations and loading conditions are also being developed. The results of R&D will be incorporated in a JSME (Japan Society of Mechanical Engineers) code for the design and construction of fast reactors
Multiple ferromagnetic transitions and structural distortion in the van der Waals ferromagnet VI3 at ambient and finite pressures
We present a combined study of zero-field (51) V and I-127 NMR at ambient pressure and specific heat and magnetization measurements under pressure up to 2.08 GPa on bulk single crystals of the van der Waals ferromagnet VI3. At ambient pressure, our results consistently demonstrate that VI3 undergoes a structural transition at T-s approximate to 78 K, followed by two subsequent ferromagnetic transitions at T-FM1 approximate to 50 K and T-FM2 approximate to 36 K upon cooling. At lowest temperature (T \u3c T-FM2), two magnetically ordered V sites exist, whereas only one magnetically ordered V site is observed for T-FM1 \u3c T \u3c T-FM2. Whereas T-FM1 is almost unaffected by external pressure, T-FM2 is highly responsive to pressure and merges with the T-FM1 line at p 0.6 GPa. At even higher pressures (p approximate to 1.25 GPa), the T-FM2 line merges with the structural transition at T-s which becomes moderately suppressed with p for p \u3c 1.25 GPa. Taken together, our data point toward a complex magnetic structure and an interesting interplay of magnetic and structural degrees of freedom in VI3
Antiallergic Activity of 6-Deoxy-2-O-methyl-6-(N-hexadecanoyl)amino-L-ascorbic Acid
Allergy is an excessive immune response to a specific antigen. Type I allergies, such as hay fever and food allergies, have increased significantly in recent years and have become a worldwide problem. We previously reported that an ascorbic acid derivative having palmitoyl and glucosyl groups, 2-O-α-D-glucopyranosyl-6-O-hexadecanoyl-L-ascorbic acid (6-sPalm-AA-2G), showed inhibitory effects on degranulation in vitro and on the passive cutaneous anaphylaxis (PCA) reaction in mice. In this study, several palmitoyl derivatives of ascorbic acid were synthesized and a structureâactivity relationship study was performed to discover more potent ascorbic acid derivatives with degranulation inhibitory activity. 6-Deoxy-2-O-methyl-6-(N-hexadecanoyl)amino-L-ascorbic acid (2-Me-6-N-Palm-AA), in which a methyl group was introduced into the hydroxyl group at the C-2 position of ascorbic acid and in which the hydroxyl group at the C-6 position was substituted with an N-palmitoyl group, exhibited much higher inhibitory activity for degranulation in vitro than did 6-sPalm-AA-2G. 2-Me-6-N-Palm-AA strongly inhibit the PCA reaction in mice at lower doses than those of 6-sPalm-AA-2G. These findings suggest that 2-Me-6-N-Palm-AA may be a promising therapeutic candidate for allergic diseases
Micromachined high-aspect-ratio parylene beam and its application to low-frequency seismometer
A new microfabrication technology for high-aspect-ratio Parylene structure is developed for soft spring applications and applied to in-plane seismometer which covers low frequency (<1 Hz) and small acceleration range. Parylene beams having 10-40 /spl mu/m wide and an aspect ratio of 10-30 were successfully fabricated. Since Parylene has a small Young's modulus and is non-brittle material, high-aspect-ratio robust beam having spring constant on the order of 1 x 10^(-3) N/m was realized. A prototype capacitive seismometer was also made, and its resonant frequency and noise spectral density was respectively measured to be 37 Hz and 45 ”g / âHz Since the Brownian noise is only 25 ng ”g / âHz, seismometer having much lower noise floor may be feasible using this new technology
Magnetic fluctuations and superconducting properties of CaKFe4As4 studied by 75As NMR
We report As nuclear magnetic resonance (NMR) studies on a new
iron-based superconductor CaKFeAs with = 35 K. As
NMR spectra show two distinct lines corresponding to the As(1) and As(2) sites
close to the K and Ca layers, respectively, revealing that K and Ca layers are
well ordered without site inversions. We found that nuclear quadrupole
frequencies of the As(1) and As(2) sites show an opposite
temperature () dependence. Nearly independent behavior of the Knight
shifts are observed in the normal state, and a sudden decrease in in
the superconducting (SC) state clearly evidences spin-singlet Cooper pairs.
As spin-lattice relaxation rates 1/ show a power law dependence
with different exponents for the two As sites. The isotropic antiferromagnetic
spin fluctuations characterized by the wavevector = (, 0) or (0,
) in the single-iron Brillouin zone notation are revealed by 1/ and
measurements. Such magnetic fluctuations are necessary to explain the
observed temperature dependence of the As quadrupole frequencies, as
evidenced by our first-principles calculations. In the SC state, 1/ shows
a rapid decrease below without a Hebel-Slichter peak and decreases
exponentially at low , consistent with an nodeless two-gap
superconductor.Comment: 9 pages, 6 figures, accepted for publication in Phys.Rev.
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