Highly accurate SNR measurement using the covariance of two SEM images with the identical view

Quality of an SEM image is strongly influenced by the extent of noise. As a well-known method in the field of SEM, the covariance is applied to measure the signal-to-noise ratio (SNR). This method has potential ability for highly accurate measurement of the SNR, which is hardly known until now. If the precautions discussed in this article are adopted, that method can demonstrate its real ability. These precautions are strongly related to "proper acquisition of two images with the identical view," "alignment of an aperture diaphragm," "reduction of charging phenomena," "elimination of particular noises," and "accurate focusing," As necessary, characteristics in SEM signal and noise are investigated from a few standpoints. When using the maximum performance of this measurement, SNR of many SEM images obtained in a variety of the SEM operating conditions and specimens can be measured accurately.     

Theoretical and evolutionary parameter tuning of neural oscillators with a double-chain structure for generating rhythmic signals

A neural oscillator with a double-chain structure is one of the central pattern generator models used to simulate and understand rhythmic movements in living organisms. However, it is difficult to reproduce desired rhythmic signals by tuning an enormous number of parameters of neural oscillators. In this study, we propose an automatic tuning method consisting of two parts. The first involves tuning rules for both the time constants and the amplitude of the oscillatory outputs based on theoretical analyses of the relationship between parameters and outputs of the neural oscillators. The second involves an evolutionary tuning method with a two-step genetic algorithm (GA), consisting of a global GA and a local GA, for tuning parameters such as neural connection weights that have no exact tuning rule. Using numerical experiments, we confirmed that the proposed tuning method could successfully tune all parameters and generate sinusoidal waves. The tuning performance of the proposed method was less affected by factors such as the number of excitatory oscillators or the desired outputs. Furthermore, the proposed method was applied to the parameter-tuning problem of some types of artificial and biological wave reproduction and yielded optimal parameter values that generated complex rhythmic signals in Caenorhabditis elegans without trial and error.     

Antiferromagnetic ordering of enhanced nuclear spin in Cs2NaHoCl6

The field dependence of the magnetic susceptibility at low temperatures was investigated in a single crystal of Cs₂NaHoCl₆. The result is well explained by the second-order Zeeman splitting of the electronic ground state with a nonmagnetic ₃ doublet. Enhanced nuclear cooling experiments were carried out. Antiferromagnetic ordering of the enhanced nuclear spin system was observed at about 1.5 mK.     

Colorimetric microdetermination of sulphites in foods by use of the modified rankine apparatus. IV.

Summary Detection and determination of traces of sulphites in foods was attempted by use of the modified Rankine apparatus and pararosaniline colorimetry. Replacement of alkaline titration reported previously by pararosaniline colorimetry lowered the absolute detection limit from 30 g (titration method) to 2 g. In view of clean analysis, in the color developing system, 0.1 N-sodium hydroxide was used in place of mercuric chloride solution commonly used as an absorbant of sulphites. In order to prevent oxidative decomposition of sulphites during operation, nitrogen gas was used as carrier instead of air. Dimedone and sodium azide were used for the elimination of aldehydes and nitrites, respecitvely, in the sample, which will disturb the color development of sulphites with pararosaniline-formaldehyde reagents. With this improved method, it was possible to determine the residual sulphites in frozen peeled shrimps, sugared beans and other foods with low sulphite contents accurately.

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Colorimetrische Mikrobestimmung von Sulfiten in Lebensmitteln bei Anwendung der modifizierten IV. Rankine Apparatur

Zusammenfassung Geringe Sulfitmengen in Lebensmitteln (geschälte Garnelen, gezuckerte Bohnen) können colorimetrisch bestimmt werden. Die neuentwickelte Methode beruht auf einer Kombination von colorimetrischer Bestimmung mittels p-Rosanilin und der Bestimmungsmethode nach Rankine. Auf diese Weise lassen sich Gehalte von 2 g noch genau bestimmen. Bei der Farbentwicklung wurde das giftige Quecksilbertetrachlorid durch 0.1 n-NaOH ersetzt, anstelle von Luft Stickstoff als Trägergas verwendet und somit eine Oxydation des Sulfits während der Bestimmung vermieden. Da Nitrit und Aldehyde die Farbentwicklung stören, wurde ihr Einfluß durch Dimedon und Natriumazid ausgeschaltet.

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Studies on the Analyses of Sulphites in Foods (IV)     

Breakdown Phenomena in Point-to-Point Gaps

Measurements with multiple techniques delineating the complete sequence of events from the primary streamer to the formation of the spark channel for relatively small point-to-point gaps are reported. The pulsed potential with 0.4 μs rise time and 1800 μs decay time was applied to the point-to-point gap, of which length was changed from 6 to 14 cm. The light pulses were observed by 5 photomultipliers as well as current and potential wave. It is shown that the spark channel can be materialized through the following three processes: 1) initial process, in which the primary, the secondary, and the tertiary streamers develop from both point electrodes into gap, and the ionizing wave bridges the gap; 2) intermediate process, in which the dark period proceeds with ion and electron movement if the applied potential is around the mean breakdown potential, or in the other case, the ``leader' develops from the anode with the help of ionizing waves; and 3) final process, in which the channel is highly ionized at first by the ionizing wave, then gas heating, to lead the formation of a spark channel. On the bases of the measurements of streamer speed and current, the ion and electron density were calculated. It is estimated that starting with the primary streamer with an electron density of 1012 cm-3, the electron density in the streamer channel is augmented by the ionizing wave up to 1012cm -3 when the gap is bridged by the ionizing wave.     

Solidification of coal fly ash using hydrothermal processing method

Solidification of Coal Fly-ash (CFA) has been carried out using a hydrothermal processing method. In the hydrothermal processing, the CFA was first compacted in a mold at 20 - 50 MPa, and then hydrothermally cured in an autoclave. The hydrothermal curing was performed at 150 – 250°C for 15 – 60 h. The experimental results showed that NaOH solution, Ca(OH)₂ content, compaction pressure, autoclave curing temperature and time significantly affected the strength of solidified bodies. The most important strength-producing constituent in the solidified bodies produced with CFA was tobermorite, or tobermorite-like calcium silicate hydrate. When the CaO/SiO₂ ratio of the starting material was close to 0.83, tobermorite readily formed and the formed tobermorite enhanced the strength of solidified bodies. The tensile strength determined by the Brazilian test reached more than 10 MPa under the hydrothermal processing. As such, the hydrothermal processing method may provide a high potential for recycling CFA on a large scale.     

Electrical Inhomogeneity at the Mott Transition in the Band Width Controlled κ-(BEDT-TTF)2Cu[N(CN)2Br

The electronic phase separation on macroscopic scale is studied in the organic Mott system κ-(BEDT-TTF)₂Cu[N(CN)₂]Br by means of scanning microregion infrared spectroscopy using the synchrotron radiation. The phase separation appears in the vicinity of the Mott boundary in the single crystals of which the band width is controlled by partly substituting the BEDT-TTF molecule with the deuterated one. The transport properties under the phase separation are considered to be influenced by the percolation process of the domains.     

Preparation and dielectric properties of polycrystalline films with dense nano-structured BaTiO3 by chemical vapor deposition using inductively coupled plasma

To clarify the dielectric properties of BaTiO₃ with nanometer size region, it is necessary to fabricate the dense structure composed of BaTiO₃ nanoparticles. In the present study, BaTiO₃ nanoparticles were directly deposited on Pt/Al₂O₃/SiO₂/Si substrate by introducing Ba(DPM)₂ and Ti(OiPr)₄ into an inductively coupled plasma (ICP). The optimal condition for preparing dense structure of BaTiO₃ nanoparticles was investigated by changing the substrate temperature. Single phase BaTiO₃ of perovskite structure was obtained at the substrate temperatures between 773 and 1173 K. The dense structure of BaTiO₃ nanoparticles with particle sizes of about 30 nm was successfully obtained at the substrate temperature of 773 K. At the substrate temperature>873 K, the deposited nanoparticles sintered to be the columnar structure. The ε_r and tan δ of the BaTiO₃ nanoparticles were estimated to be 285 and 6.6%, respectively (1 kHz and 100 mV). The phase of the BaTiO₃ nanoparticles were found to be paraelectric by the measurement of C-V curves. The breakdown field of the dense structure of BaTiO₃ nanoparticles was estimated to be 649 kV/cm according to I-V curves. These features are favorable for applying the structure to the dielectric layer of multilayer capacitors.