Needle- and plate-like NaTaO3 have been synthesized at low temperatures (<500°C) in three steps by a molten NaOH method. First, Na3TaO4 precursor was synthesized by the reaction of Ta2O5 with a ...molten NaOH at 450°C for 50 h in air. Then, Na3TaO3 precursor reacted with H2O to form needle-like Na7(H3O)Ta6O19·14H2O and plate-like Na8Ta6O19·24H2O intermediates in the process to wash the excess NaOH in the crucible with H2O. The needle-like Na7(H3O)Ta6O19·14H2O was the major product. Then, these intermediates transformed to NaTaO3 through dehydrate intermediates by heating at above 500°C. The obtained NaTaO3 had needle- and plate-like morphology with a perovskite structure.
Needle-like NaNbO3 has been prepared in two steps by a molten NaOH method. First, Na7(H3O)Nb6O19·14H2O precursor was synthesized by the reaction of Nb2O5 with a molten NaOH at 450°C for 50 h in air. ...The Na7(H3O)Nb6O19·14H2O precursor was a needle-like single crystal 0.25–1.5 µm wide and >3 µm long. Then, the Na7(H3O)Nb6O19·14H2O precursor crystal transformed to NaNbO3 through an intermediate Na7(H3O)Nb6O19 by a heating above 500°C. The NaNbO3 was a needle-like polycrystal with a perovskite-type structure.
Summary form only given. Recently, metal-halide perovskite semiconductors have been extensively studied because of their potential use in solar-cell, photodetector, light-emitting-diode, and laser ...applications. In particular, perovskite nanocrystals (NCs) are gaining more and more attention because their optical spectra can be manipulated by changing the NC size and the halogen composition 1. In contrast to the conventionally structured NCs such as colloidal CdSe NCs, high-quality perovskite NCs with unique cubic shapes and large sizes can be fabricated. However, their intrinsic photocarrier recombination dynamics have not yet been understood. Especially, the recombination dynamics of exciton complexes including biexcitons and charged excitons (trions) are complicated due to the fast Auger recombination 2. Thus, a combination of different optical techniques for ensemble and single NC samples should be performed for a deep understanding of multiexciton dynamics in perovskites.In this work, we report on the multiexciton dynamics revealed by NC-ensemble transient absorption (TA), time-resolved photoluminescence (TR-PL), and single-NC-PL spectroscopy. The samples used in this study were cubic-shaped CsPbBr 3 NCs as shown in the inset of Fig. 1. The absorption cross-section of the NCs was determined by TA measurements 3, which enables us to evaluate the average number of excitons generated in NCs. For weak photoexcitation, single exponential decays of excitons were observed with the lifetime of a few nanoseconds as shown in Fig. 1. In contrast, multiexcitons were observed under high photoexcitation. The biexcitons and trions showed fast decays due to the Auger recombination within a few tens and a few hundreds of picoseconds, respectively. The fast decay components within 1 ns become stronger with increasing excitation fluence. These excitation fluence dependences suggest that the TA dynamics are explained by excitons, trions, and biexcitons. To reveal the recombination dynamics of biexcitons and trions, we performed single-NC-PL measurements. The PL decay curve and second-order photon correlation (g (2) ) were simultaneously measured on the single NCs using a single-photon counting method. The PL lifetimes of excitons and trions were consistent well with the results of TA measurements. From the center peak of the g (2) curve, which corresponds to the cascade emission (sequential two-photon emission of biexcitons), the lifetime and PL quantum yield (QY) of biexcitons were evaluated for the first time. The obtained QY of biexcitons is surprisingly larger than the values predicted by a statistical scaling law model 2. From the comparison of TA and single-NC-PL measurements, we successfully clarified the recombination rates of biexcitons, trions, and excitons. Part of this work was supported by CREST, JST.
Until now, replacing existing equipment with new without interruption has been technically possible because the power supply has been DC, and we have only had to control voltage. Increasingly ...customers are using AC power supply, and their need for uninterrupted power to their equipment is also increasing. However in the case of AC power supply, replacing equipment without interruption is difficult because we have to control voltage, phase, phase rotation, and phase difference. This paper presents a portable-transfer switch that we developed to enable UPS replacement for AC equipment without such interruption. It allows electrical workers to replace an existing UPS to a new one safely without interrupting the supply of power.
1. The exact role of the parathyroid hormone-related peptide (PTHrP) is not fully understood. We used immunohistochemistry to localize the PTHrP and its receptor in the brain of the red stingray, ...particularly in the saccus vasculosus (SV) and choroid plexus. 2. Immunoreactive PTHrP and its receptor were detected in the epithelial cells of the SV and the choroid plexus. In addition, the neuronal perikarya in the nucleus of the SV located in the hypothalamus is positive for the PTHrP. 3. No PTHrP-containing neurons were detected in the choroid plexus. Extracts of SV and choroid plexus showed positive reactions against the PTHrP and its receptor antibody in Western blot analysis. 4. High levels of immunoreactive PTHrP were detected in the plasma equivalent to those present in human humoral malignant hypercalcemia. In contrast, the immunoreactive PTHrP concentration in the cerebrospinal fluid was below detectable levels. 5. Our results suggest that the regulation of the PTHrP in the SV differs from that in the choroid plexus in the red stingray.
The neuronal and laminar organization of the optic tectum (OT) in the river lamprey was studied using the rapid Golgi method. Based primarily on the distribution pattern of the dendrites, the OT ...neurons were divided into vertical, horizontal and stellate neurons. The river lamprey OT shows a laminar structure consisting of eight concentric strata. The stratum ependymale consists of several rows of ependymal cells. The stratum cellulare periventriculare contains one to two rows of vertical neurons. The stratum fibrosum periventriculare is thin and contains a few vertical neurons. The stratum cellulare et fibrosum internum consists of several alternating cellular and fibrous layers: a large variety of vertical and horizontal neurons are distributed in this stratum. The stratum fibrosum centrale consists of compact horizontal fiber bundles, among which a few horizontal neurons are disseminated. In the stratum cellulare et fibrosum externum, numerous fibers run horizontally in a loosely organized plexus; various types of vertical, horizontal and stellate neurons are distributed among these fibers. The stratum opticum is the main terminal area of the optic nerve, and contains stellate and horizontal neurons. The stratum marginale is a thin layer and consists of sparse populations of vertical and horizontal neurons. Besides the above outer to inner laminar structure, the OT is divided into medial (m-OT) and lateral parts (1-OT), based primarily on the distribution pattern of the dendrites. The dendrites of neurons in the m-OT are distributed almost exclusively within the OT. On the other hand, the dendrites of some neurons in the 1-OT extended into the confines of the torus semicircularis (TS), and conversely, the dendrites of some neurons in the TS are distributed in the 1-OT. These findings are discussed in relation to the neuronal and laminar organization of the OT in other lamprey species and to recent hodological studies.
The effects of perforated film package (PFP) on the gas concentrations and respiration rates of fresh-cut cabbage with initial O2 5, 8, 10 and 21% were studied at 5 and 20 deg C. The microbial ...growth, appearance, flavor and ascorbic acid content were also determined. The respiration rates of fresh-cut cabbages were suppressed under initial low O2 during storage of 4 days, especially in 5 and 8% O2 concentrations. The anaerobic respiration did not occur under low O2 levels. It was also found that fresh-cut cabbages had better color retention and quality, reduced respiration rate and microbial population in PFP. Although there was the difference of quality attributes between PFP and MAP, but no significant difference was found. The effect of initial low O2 5% was the most important among different levels of initial low O2 according to the oxidation of ascorbic acid (AA) and browning of fresh-cut cabbage. Microbial analysis also showed that total count on the surface of fresh-cut cabbage was lowest among initial low O2 treatments. Total ascorbic acid (TAA) decreased by AA oxidation after cutting. Loss in TAA was much lower in PFP than that in MAP. Moreover, The results of sensory evaluation showed that there were no differences in all treatments at 5 deg C throughout storage. At 20 deg C, flavor reached 2-grade in all treatments and become 3-grade by 4 days in 21%MAP. The appearances were reached 2-grades after 3 days in 10%PFP and 21%MAP. These suggest that better quality of fresh-cut cabbage could be obtained from the combination of PFP with initiai O2 5-8% level and 5 deg C.
The neuronal organization of the spinal cord in red stingray was studied using the rapid Golgi method. The gray matter of the spinal cord was divided into seven laminae: RS-I, RS-II, RS-III, RS-IV, ...RS-V, RS-VI and RS-VII. RS-I is cell dense lamina which occupies the major part of the dorsal horn and corresponds to laminae I and II of the spinal cord of mammals, birds and reptiles. The neurons of the lamina I are interspersed with those of lamina II, without forming a discrete lamina. RS-II is located at the base of the dorsal horn and is considered to correspond to the nucleus proprius. RS-III and IV form the intermediate zone and are highly reticulated. A few neurons of various shapes and sizes are distributed among the numerous fibers. The nuclei such as the intermediolateral, intermediomedial or Clarke's nucleus cannot be identified in the intermediate zone. RS-V and VI constitute the ventral horn. RS-V occupies the major part of the ventral horn and contains motoneurons which are distributed diffusely, without forming any distinct cell groups. RS-VI is located in the ventromedial part of the ventral horn, contains commissural neurons and correspond to lamina VIII. RS-VII is a small area surrounding the central canal and corresponds to lamina X. Thus, while the major features of the spinal cord of the red stingray can be correlated with those of the spinal cord of mammals, birds and reptiles, the neuronal organization of the spinal cord of the red stingray remains in an undifferentiated state.
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