Catholic discharge of graphite fluoride, (CF)n, prepared from several carbon materials, in lithium organic electrolyte batteries

Discharge characteristic of (CF)_n prepared from four kinds of carbon material, that is, natural graphite, petroleum coke, carbon black, and active carbon, were studied on the cell combined with a lithium anode and an organic electrolyte. (CF)_n from natural graphite and petroleum coke showed more stable discharge potential and higher energy density than those from carbon black and active carbon. This is explained in terms of the structures of their starting carbon materials. The orientation of the crystalline in (CF)_n, which inherited from the starting carbon, determines the potential stability. The overpotential (η) at the earlier discharge state was influenced by the interlayer spacing [d(001)] rather than the kind of carbon materials. A plot of η against d(001) of each (CF)_n indicates a negative linear correlation, viz., η decrease with increasing d(001). To study the effect of the degree of the regular layer-stacking, three (CF)_n having the nearly same d(001) but different β(001), the half-value of the (001) peak in the X-ray diffraction pattern, were prepared from natural graphite, and their discharge behavior compared with each other. The discharge potential increased with increasing β(001).     

Cation-Responsive Fluorescence Of Dansyl-Labeled Polyanions Bearing Crown Ether Units

Anionic polymers bearing both crown ether units and Dansyl units were prepared by radical terpolymerization of the corresponding monomers, and the effect of cations on the fluorescence properties of the polymers was studied in aqueous media. The fluorescence peaks of the polymers are observed at 500–527 nm. The fluorescence quantum yields () of the polymers were found to be 6.3 × 10^–3–4.0 × 10^–1, depending on the polymer structure. On the addition of alkali metal cations, the fluorescence intensity increases in the order LiCl < NaCl < KCl < RbCl < CsCl. The polymer which has almost-equimolar amounts of crown ether groups and–COOH groups shows the highest responsiveness to the cations added. The structure of the anionic moieties in polymers strongly affects the cation-responsive fluorescence. The mechanism for the cation-induced changes in fluorescence is discussed.     

High-power 1.625-μm strained multiple-quantum-well lasers as a light source for optical time-domain reflectometers

An optical output power of 160 mW has been successfully achieved in 1.625-m strained multiple-quantum-well lasers at a forward current of 800 mA under pulsed operation. Such a high output power has been achieved by optimizing the separated confinement heterostructure layer thickness. The operating life of high-power 1.625-m lasers has been estimated from the results of accelerated ageing at an ambient temperature of 45°C and 500 mA under continuous-wave operation. No significant change in the optical output power was observed up to 2000 hours. The mean time to failure is estimated to be about 4.5×10⁴ hours at 500 mA and 45°C.     

Removal of residual images in parallel phase-shifting digital holography

Parallel phase-shifting digital holography (PPSDH) is a technique of single-shot phase-shifting digital holography. We found that there are two problems with this technique. (1) Some extraneous noises caused by the intensity unevenness of the reference wave become slightly superimposed on the object image. (2) The conjugate image cannot be completely removed. This is because the object wave causes the phase-shift error by illuminating an image sensor with a large incident angle. To solve these problems, we propose an algorithm for removing residual 0th-order diffraction and conjugate images in PPSDH. In the proposed algorithm, we modified phase-shifting interferometry in order to work through the unevenness of the intensity distribution and applied the Fourier transform technique to PPSDH to remove the residual conjugate image. The effectiveness of the proposed algorithm was experimentally verified.     

Detection and evaluation of security features embedded in paper using spectral-domain optical coherence tomography

We propose a new method for authenticating valuable paper sheets such as gift coupons, tickets, and cheques with the use of optical coherence tomography (OCT). This method is based on the detection and evaluation of cross-sectional structural characteristics of valuable paper sheets provided with security features. Commonly used as a security feature is a security thread, which is embedded in such paper sheets. In this paper, the nondestructive detection of the embedded security thread is demonstrated using spectral-domain OCT. The results showed that the security thread was clearly visualized in the OCT image despite the highly scattering nature of papers.     

Application of Odorless Thiols for the Cleavage of 2‐ and 4‐Nitrobenzenesulfonamides

Several odorless or faint‐smelling thiols were tested to cleave 2‐ and 4‐nitrobenzenesulfonyl groups, which are widely utilized for selective protection and activation of amines. p‐Mercaptobenzoic acid (7) was found to be the most useful thiol for cleaving the o‐ and p‐nosyl groups in terms of ease of separation of the product from the workup residue, reaction temperature, and reaction time.     

Spatial-carrier phase-shifting digital holography utilizing spatial frequency analysis for the correction of the phase-shift error

We propose a single-shot digital holography in which the complex amplitude distribution is obtained by spatial-carrier phase-shifting (SCPS) interferometry and the correction of the inherent phase-shift error occurred in this interferometry. The 0th order diffraction wave and the conjugate image are removed by phase-shifting interferometry and Fourier transform technique, respectively. The inherent error is corrected in the spatial frequency domain. The proposed technique does not require an iteration process to remove the unwanted images and has an advantage in the field of view in comparison to a conventional SCPS technique.     

Preparation and application of odorless 1,3-propanedithiol reagents

2-Dodecyl-1,3-propanedithiol (2a) was prepared without a malodorous procedure as an odorless reagent that was usable in place of 1,3-propanedithiol (1) in organic reactions, e.g., in the reduction of azides and protection of carbonyl groups. The 1,3-dithioacetals obtained in the latter reaction were effectively reduced to methylene with Raney nickel and reconverted to the original carbonyl compounds by hydrolysis with N-bromosuccinimide in aqueous 2-butanone. In addition, the anion of 1,3-dithiane prepared from 2a and formaldehyde could be utilized as a synthetic equivalent of an anionic carbonyl carbon.     

1.625-μm high-power strained multiple quantum well lasers for optical time-domain reflectometers

An optical output power exceeding 210 mW has been achieved using 1.625-μm strained multiple quantum well lasers at a forward current of 800 mA under pulsed operation. We introduced tensile-strained barrier layers to increase internal quantum efficiency. High quantum efficiency is attributed to improved of hole injection efficiency and suppressed electron overflow from wells. The 1.625-μm high-power lasers are expected to be applied to optical time-domain reflectometers, which enable regular communication light to be used.