Development of the fiber neutron monitor for the energy range 15-100 MeV on the International Space Station (ISS)

In order to investigate the space environment, a new neutron monitor has been prepared. The sensor consists of scintillation fibers (FIB) and will be on board the exposed facility of the Japanese Experimental module (Kibo) of the International Space Station (ISS). The sensor is one of the instruments which measures the particle and plasma environment around the ISS. The sensor will be used by the cosmonauts who work on the ISS, to help them avoid a strong particle radiation which may arrive soon. We believe that such an alert is necessary for the cosmonauts to prevent unnecessary radiation from the sun. Furthermore, the sensor will be very useful in understanding the particle acceleration mechanism at the solar surface. The design of the Engineering Model (EM) was finished and its properties were investigated. This report discusses these results.     

Bottom-up fabrication and piezoelectric properties of CaBi<Subscript>4</Subscript>Ti<Subscript>4</Subscript>O<Subscript>15</Subscript> micro-plateaus

CaBi₄Ti₄O₁₅ (CBTi144) micro-plateaus were fabricated on Si wafers and Pt foils using a self-assembled monolayer (SAM) and a complex metal alkoxide solution. The micro-plateaus are delineated by metal masks, which are used for shadowing against the ultraviolet (UV) irradiation for decomposition of SAM to make the surface hydrophilic. The micro-plateaus crystallized to a ferroelectric phase with random orientation. The crystallization depended on the SAM-derived ultra thin layers at the surface of the substrates. The primitive PFM measurements without any top electrodes confirmed that the micro-plateaus exhibited the piezoresponse behaviors. The piezoelectric constant, d₃₃, had some distribution, and the maximum d₃₃ was confirmed as about 45 pm/V, which is identical to the d₃₃ of the polar-axis oriented CBTi144 thin films. PACS 77.84.-s; 81.20.Fw; 77.65.-j     

Initial oxidation of Ni(1 1 1) observed by electron emission microscopy: PEEM and MEEM

The initial oxidation of Ni(1 1 1) in the temperature range of 550-700 K has been monitored by photoelectron emission microscopy (PEEM) and metastable-atom electron emission microscopy (MEEM). The PEEM and MEEM images show uniform patterns for the chemisorbed overlayer, reflecting the electronic homogeneity as seen at the μm scale. During the nucleation and lateral growth of oxide, however, the μm-scale pattern due to the formation of oxide domains appears and its evolution depends strongly on the substrate temperature and dose pressure of gaseous O₂. Our data indicate that the high-temperature oxidation is regarded as a successive multi-nucleation process in a reaction-diffusion field.     

Real-time imaging of ion uptake from root to above-ground part of the plant using conventional beta-ray emitters

We present real-time imaging of ³²P-phosphate within a living plant as well as that in culture solution toward roots. The above-ground part of the plant was irradiated with light from LED and roots were kept in dark. The plant was Lotus japonicus, cv. Miyakojima MG20 and real-time ³²P-phosphate uptake manners in young, flowering and adult phase were visualized. In the case of young plant, there was a preferential translocation of ³²P in younger leaves. When the sample was treated with phosphate deficient condition, ³²P uptake amount was much higher. In an adult phase, ³²P uptake was high at pods.     

Neutron scattering by inhomogenous distribution of proton polarization produced by the dynamic nuclear polarization

The coherent neutron scattering from polarized proton clusters was observed. Clusters of polarized protons were formed in dicychrohexyl 18-crown-6 (C₂₀H₃₆D₆) molecules. The proton polarization in the molecule was produced by the dynamic nuclear polarization (DNP). The proton polarization distribution in the DNP process was also measured in propanediol. In the stationary state, no inhomogenous distribution was found.     

Swelling of poly(ethylene oxide) gel in aqueous solutions of sodium dodecyl sulfate with added sodium chloride

The swelling behavior of poly(ethylene oxide) (PEO) gels in aqueous solutions of sodium dodecyl sulfate (SDS) with and without NaCl was investigated. In the absence of NaCl, PEO gels with different degrees of cross-linking began to swell from a concentration lower than the critical micelle concentration (cmc) of SDS, then showed sigmoidal enhancements of swelling in a higher SDS concentration region until the degrees of swelling reached maximum values. The SDS concentration at which the swelling began to appear was in reasonable agreement with the critical aggregation concentration (cac) value reported for the aqueous PEO system. For the cases where NaCl was present, the swelling behavior of PEO gel was different from that when NaCl was absent in the following way. The concentrations where the swelling begins to appear, and hence those where the degree of swelling rises steeply, decreased with an increase in NaCl concentration. The ultimate degrees of swelling at higher concentration regions also decreased with an increase in the NaCl concentration. The lowering of the SDS concentrations at which the PEO gel began to swell is in line with the decreases in the cmc of SDS solutions containing NaCl and also with the decreases in the cac of PEO solution. Electronic Publication     

A Thermal And Structural Study on Lanthanum Hexacyanocobaltate(III) Pentahydrate. Part II

The thermal dehydration of La[Co(CN)₆]⋅5H₂O proceeded through at least three stages from the temperature range of30~230°C, and an abrupt mass loss occurred around 350°C and the perovskite type oxide,LaCoO₃ was obtained at 1000°C. After dehydration, the color of the anhydride changed from white to pale blue around 230°C and furthermore, the color changed to blue around 290°C. These color changes were discussed on the basis of the changes of coordination structures around Co ions. In La[Co(CN)₆]⋅5H₂O, Co³⁺ ions lie at the center of the O_h crystal field consisted of six CN^– ions. However, in the pale blue specimen, Co³⁺ ions were situated in the center of D_4h crystal field which was distorted the O_h one by lengthening of the trans CN^– ions along z-axis. In the blue specimen, Co³⁺ ions were reduced to Co²⁺ ions which were situated in the T_d crystal field formed by four CN^–ions as [Co(CN)₄]^2–. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis and properties of amino acid esters of hydroxypropyl cellulose

The amino acid esters of hydroxypropyl cellulose (HPC) [R′ = H ( 2a ), CH₃ ( 2b ), CH₂CH(CH₃)₂ ( 2c ), CH₂CONH₂ ( 2d ), CH₂CH₂CONH₂ ( 2e ), CH₂CH₂CH₂CH₂ NHOCOC(CH₃)₃ ( 2f )] were synthesized in good yield by the reaction of t‐butoxycarbonyl (t‐Boc)‐protected amino acids with hydroxy groups of HPC ( 1 ; molar substitution (MS), 4.61). The amino acid functionalities displaying varied chemical nature, shape, and bulk were utilized and the bulk of the substituent on the α‐carbon of amino acids was elucidated to be of vital significance for the observed degree of incorporation (DS_Est). The ¹H NMR spectra and elemental analysis were employed to determine the degree of incorporation of amino acid moiety (DS_Est) and almost complete substitution of the hydroxy protons was revealed for 2a , 2b , and 2f . The presence of the peaks characteristic of the carbonyl group in the FTIR spectra furnished further evidence for the successful esterification of HPC. The starting as well as the resulting polymers ( 1 and 2a – f ) were soluble in polar organic solvents; however, the esterification of 1 with bulky organic moieties resulted in an increased hydrophobicity as all of the amino acid‐functionalized polymers ( 2a – f ) were insoluble in water. The onset temperatures of weight loss of 2a – f were 175–230 °C, indicating fair thermal stability. The amino acid functionalization led to the enhanced polymer chain stiffness, and the glass transition temperatures of the derivatized polymers were 30–40 °C higher than that of 1 (T_g 3.9 °C; cf. T_g of 2a – f , 35.1–43.3 °C). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2326–2334, 2008