Go Ono

Structure and physical properties of a hydrogen-bonded self-assembled material composed of a carbamoylmethyl substituted TTF derivative

Crystal structures of the carbamoylmethyl substituted TTF derivative AMET are characterized by polymeric hydrogen bonding between amide groups. As a result, the TTF moieties stack in parallel even in the neutral crystal. The nu;NH absorbtions of neutral AMET at 3426 and 3184cm1 show shifts to lower wavenumber, Delta;k, of 37 and 58cm1, respectively, at 4.1GPa. Therefore the shrinkage of the NH‥O distance is estimated to be ca. 0.04 at this pressure. The pressure dependence of the IR spectra of iodine-doped samples at doping ratios of less than 45 was exactly the same as that for a neutral sample, suggesting that the hydrogen bonding pattern is not affected significantly upon doping.Although crystalline AMET is an insulator in the neutral state (sigma;rt=ca. 108 Scm1), the conductivity is enhanced by a factor of 107 upon iodine doping of 45mol (sigma;rt=1.2101 Scm1). Furthermore, the conductivity increases as a function of the external pressure, and the sigma;rt of a 5 iodine-doped sample increased three-fold at 1.0GPa. The enhanced conductivity of iodine-doped samples may be ascribed to the increase in the overlap between the donor moieties based on the shrinkage of the hydrogen bond of the carbamoylmethyl group.

Generalized Attitude Model for Momentum-Biased Solar Sail Spacecraft

This paper describes a method of modeling general attitude dynamics of a nonspinning momentum-biased spacecraft under strong influence of solar radiation pressure. This model, called the “generalized sail dynamics model,” can be applied to realistic solar sail spacecraft with nonflat surfaces and nonuniform optical reflectance. A coarse sun-pointing momentum-biased spacecraft is especially of interest, for which an approximate solution of the equations of motion is analytically derived. Stability and fundamental characteristics of momentum-biased spacecraft dynamics as well as theoretical relations with past dynamics models are discussed in detail. Furthermore, unique attitude motion predicted by the novel model is verified with flight data of the Japanese interplanetary probe, Hayabusa 2.

Structure And Property Of Cross-Cyclophane Twin Donors

Abstract Cross-cyclophane twin donors, in which long axes of TTF units are fixed in a cross orientation by four ethylenedithio (x-CPTD (II)) and four trimethylenedithio (x-CPTD (III)) chains, were designed and prepared. Although the donor ability of x-CPTD (II) was low due to a heavy bending of the donor units, that of x-CPTD (III) was the same as BEDT-TTF. The crystal structures of a charge transfer complex, x-CPTD (III) ·TCNQ, and an ion radical salt, x-CPTD (III)·Br (1,1,2-TCE)2, revealed that x-CPTD (III) has an ability to construct characteristic self-assembled structures, recognizing a size and a shape of acceptors or counter ions. The almost isotropic conducting property (σr,t //a = 1.0 × 10−2 S · cm−1, σr,t //a = 5.5 × 10−3 S · cm−1) of the ion radical salt was interpreted based on the unique molecular structure of x-CFTD (III).

Evaluation of Sail Mechanics of IKAROS on its Slow-Spin and Reverse-Spin Operation

In the post operational phase of spin type solar sail “IKAROS”, a slow-spin operation and a reverse-spin operation were conducted to acquire basic knowledge of mechanics of sail membrane. The flight data indicates that the sail membrane kept its shape against the solar radiation pressure even with low centrifugal force.

Nonflatness of Solar Sail Membrane Predicted by Nonlinear Finite Element Analyses

This paper identifies the possible causes of two phenomena observed in the membrane of the solar sail IKAROS: its nonflat shape and high out-of-plane stiffness. IKAROS’ flight data showed that the sail was significantly nonflat. In addition, the out-of-plane deformation of the membrane was smaller than that predicted preflight by numerical simulations, which indicates higher out-of-plane stiffness than expected. This study hypothesized that the initial deformation of the membrane could have been induced by the curvatures of the thin film solar cells and the reflection control devices attached on the sail. The effects of the curvatures on the sail shape were examined through geometrically nonlinear finite element analyses of a 1/4 IKAROS membrane with shell elements. The analysis results indicated that the on-orbit IKAROS membrane could be nonflat owing to the propagation of wrinkles throughout the membrane induced by the curvature of the thinfilm components. Furthermore, the out-of-plane deformation of the sail under solar pressure became very small when the entire sail was wrinkled, which explains IKAROS’ on-orbit phenomena.

One-dimensional double chain composed of carbamoylmethylthio-substituted TTF-based donor in ion radical salt

Carbamoylmethylthio-substituted TTF-based donors afforded inclusion-type salts with a BF4 counter ion or an F4-TCNQ acceptor. The crystal structures of these salts are characterized by a one-dimensional double chain composed of singly-oxidized donors via SOMO–SOMO interaction and side-by-side S⋯S contacts. Counter ions of BF4 are hydrogen-bonded to the amide groups. On the other hand, F4-TCNQ acceptors are stacked in a channel created by a stair-like arrangement of donor chains. The thermally activating magnetic susceptibility of the F4-TCNQ complex was interpreted in terms of a double-chain frustrated spin system.

Unusual Conductive Behavior of (BEDT-TTF)3Cl2 Hydrate Salts

Abstract The ion-radical salt (BEDT-TTF)3Cl2*5H2O has been prepared through electro-crystallization using halocarbons as a solvent in the presence of an aliquot of water. The crystal structure was characterized by a multi-layered structure consists of organic layers of a donor stack and inorganic layers of hydrated chloride ions. When the resistivity was measured, the salt showed a rectifying effect. This effect may be caused by the external field-induced structural transition of chloride ions coupled with the change of a hydration scheme.

Solar Radiation Pressure-Assisted Fuel-Free Sun Tracking and Its Application to Hayabusa2

This paper describes the modeling, dynamical characteristics, and implementation of an attitude control method that actively uses solar radiation pressure. The theory behind this control method is ...