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901.
Kohei Kawasaki Takahiro Sakurai Eiji Ohmichi Susumu Okubo Hitoshi Ohta Kazuyuki Matsubayashi Yoshiya Uwatoko 《Applied magnetic resonance》2015,46(9):987-992
We have developed the high-pressure electron spin resonance (ESR) system using a micro-coil in the frequency region up to around 2 GHz and potentially 10 GHz. The hybrid-type piston-cylinder pressure cell whose maximum pressure reaches 4 GPa was used. In this study, we obtained ESR spectra at 2.3 GPa successfully, which can never be obtained by the single-layer piston-cylinder pressure cell. The minimum detectable spin number was estimated to be the order of 1012 spins/G. Moreover, it is shown that the sensitivity can be improved by two orders of magnitude using the field modulation technique. This high-pressure ESR technique is a promising one to achieve the sensitivity and the high pressure simultaneously. 相似文献
902.
OPENCORE NMR: open-source core modules for implementing an integrated FPGA-based NMR spectrometer 总被引:1,自引:0,他引:1
Takeda K 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2008,192(2):218-229
A tool kit for implementing an integrated FPGA-based NMR spectrometer [K. Takeda, A highly integrated FPGA-based nuclear magnetic resonance spectrometer, Rev. Sci. Instrum. 78 (2007) 033103], referred to as the OPENCORE NMR spectrometer, is open to public. The system is composed of an FPGA chip and several peripheral boards for USB communication, direct-digital synthesis (DDS), RF transmission, signal acquisition, etc. Inside the FPGA chip have been implemented a number of digital modules including three pulse programmers, the digital part of DDS, a digital quadrature demodulator, dual digital low-pass filters, and a PC interface. These FPGA core modules are written in VHDL, and their source codes are available on our website. This work aims at providing sufficient information with which one can, given some facility in circuit board manufacturing, reproduce the OPENCORE NMR spectrometer presented here. Also, the users are encouraged to modify the design of spectrometer according to their own specific needs. A home-built NMR spectrometer can serve complementary roles to a sophisticated commercial spectrometer, should one comes across such new ideas that require heavy modification to hardware inside the spectrometer. This work can lower the barrier of building a handmade NMR spectrometer in the laboratory, and promote novel and exciting NMR experiments. 相似文献
903.
904.
The chaos control in the chaotic neural network is studied using the partial state feedback with a control signal from a few control neurons. The controlled CNN converges to one of the stored patterns with a period which depends on the initial conditions, i.e., the set of control neurons and other control parameters. We show that the controlled CNN can distinguish between two initial patterns even if they have a small difference. This implies that such a controlled CNN can be feasibly applied to information processing such as pattern recognition. 相似文献
905.
Nobuo Ueno Satoshi Kera Kazuyuki Sakamoto Koji. K. Okudaira 《Applied Physics A: Materials Science & Processing》2008,92(3):495-504
This article describes the origins of the width of the highest occupied molecular orbital (HOMO) state observed in the ultraviolet
photoemission spectra (UPS) of thin organic semiconductor films. Although much research has been performed on the electrical
properties of organic devices, a lot of crucial problems still remain. Among these problems, the charge mobility in organic
semiconductor systems is one the most important subjects to be elucidated. In order to discuss the mobility, it is essential
to understand both the intermolecular interaction and the electron-molecular vibration coupling. Experimental measurements
of the energy band dispersion give information about the intermolecular interaction, and experimental detection of the HOMO
hole-vibration coupling is indispensable to comprehend impacts of the electron-vibration coupling on the hole transport. Since
most of the information is hidden behind the finite bandwidth of the HOMO, only careful UPS measurements can provide information
on these important phenomena related to charge carrier dynamics. In this article, we summarize our recent challenges on UPS
measurements of organic thin films, which give the band dispersion of the HOMO and the HOMO hole-vibration coupling, and discuss
the origins of the UPS bandwidth that relates to the charge carrier dynamics. 相似文献
906.
Takeda K Yamamura T Kagawa A Kitagawa M 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2005,174(2):310-313
An optical system is proposed to enhance efficiency in photo-excitation to the triplet state by reshaping an original laser pulse into a train of pulses. This optical system can be used to improve the attainable nuclear spin polarization in dynamic nuclear polarization experiments using photo-excited triplet electron spins. 相似文献
907.
908.
Here we introduce a model of parametrically coupled chaotic maps on a one-dimensional lattice. In this model, each element
has its internal self-regulatory dynamics, whereby at fixed intervals of time the nonlinearity parameter at each site is adjusted
by feedback from its past evolution. Additionally, the maps are coupled sequentially and unidirectionally, to their nearest
neighbor, through the difference of their parametric variations. Interestingly we find that this model asymptotically yields
clusters of superstable oscillators with different periods. We observe that the sizes of these oscillator clusters have a
power-law distribution. Moreover, we find that the transient dynamics gives rise to a 1/f power spectrum. All these characteristics indicate self-organization and emergent scaling behavior in this system. We also
interpret the power-law characteristics of the proposed system from an ecological point of view.
相似文献
909.
Recently, much work has been done to study hydrogen behavior on solid surfaces for applications in fuel cells, semiconductor devices, and diamond-like carbon films. We have developed a hydrogen microscope making use of electron stimulated desorption (ESD) spectroscopy. A thermal-field emission type electron gun set to a low-energy range (<1 keV) is used to obtain a beam size less than 100 nm in diameter. A pulsed beam has been used to measure the time-of-flight (TOF) to detect desorbed ions from specimen surfaces. Scanning the pulsed beams across solid surfaces, a two-dimensional distribution image of hydrogen atoms can be obtained. This paper reviews some capabilities of the hydrogen microscope and a chemical state analysis for H and O adsorbed by different elements on a surface. 相似文献
910.
Huo Q Yuasa T Akatsuka T Takeda T Wu J Thet-Thet-Lwin Hyodo K Dilmanian FA 《Optics letters》2008,33(21):2494-2496
We propose a fluorescent x-ray computed tomography method using an array of detectors with an incident sheet beam, aimed at providing molecular imaging with high sensitivity and good spatial resolution. In this study, we prove the feasibility of this concept and investigate its imaging properties, including spatial and contrast resolutions and quantitativeness, by imaging an acrylic phantom and a normal mouse brain using a preliminary imaging system with monochromatic synchrotron x rays. 相似文献