Preparation and Properties of Aramid Copolymers Derived from 3,4'-ODA, 4,4'-ODA, IPC and TPC

Two series of wholly aromatic copolyamides (aramid copolymers) derived from (3-aminophenyl) (4-aminophenyl) ether (3,4'-ODA), bis(4-aminophenyl)ether(4,4'-ODA), isophthaloyl chloride (IPC), and terephthaloyl chloride (TPC), having inherent viscosity of 0.63-1.41 dL·g^-1 were synthesized. The thermal and mechanical properties of the cast films were investigated for application as hot-melt adhesives. When the aramid 341 composed of 3,4'-ODA and IPC was used, the value of adhesive joint strength at 20°C was 8.4 MPa and this value was maintained even at 230°C. And when 20 mol % of 3,4'-ODA were replaced by 4,4'-ODA, the value of adhesive joint strength at 20°C was a maximum, 16 MPa.     

Antigen specificity of antihistone antibodies in systemic sclerosis

OBJECTIVES: The aim of the study was to determine the prevalence and clinical significance of antibodies to individual histone components in systemic sclerosis (SSc). METHODS: Serum samples from patients with limited cutaneous SSc (lSSc; n = 42) and diffuse cutaneous SSc (dSSc; n = 28) were examined for IgG and/or IgM antibodies to individual histone components and complexes by enzyme linked immunosorbent assay (ELISA). RESULTS: The level of IgG antibody to total histones was significantly higher in lSSc and dSSc than in normal controls. The level of IgM antibody to total histones was significantly higher in lSSc, but not in dSSc, than in normal controls. IgG antibody to total histones tended to be increased in dSSc when compared with that in lSSc. On the other hand, IgM antibody to total histones tended to be increased in lSSc when compared with that in dSSc. Although SSc showed various antihistone specificities, H2B, H2A-H2B, (H2A-H2B)-dsDNA were main antigens recognised by IgG antibodies in both lSSc and dSSc. Although IgM antibodies to H2B and H2A-H2B were also detected in both lSSc and dSSc, serum samples from lSSc patients exhibited highest IgM reactivity with H1. CONCLUSION: SSc may be included among conditions in which heterogeneous antihistone antibodies are produced. IgM antibodies to the most accessible histone H1 may be related to mild clinical features (lSSc) and IgG antibodies to the inner core molecules of native histone such as H2B or complexes including H2B may be associated with severe clinical features (dSSc) in Ssc.     

Formation of a high polymer of acrylamide by utilizing Kolbe's electrolysis

During the electro-initiated polymerization of acrylamide by utilizing Kolbe's electrolysis as a source of free radicals in an aqueous solution of acetic acid and potassium acetate, only an oligomer with a molecular weight of 4000–6000 was obtained. However, by the addition of ferric ion, a high-polymer with a molecular weight of a few millions was obtained. The effective action of ferric ions was retarded by the presence of ferrous ion and a large amount of chloride ion. The optimum amount of ferric ion for the formation of high-polymer and the effects and roles of various ions on the process of polymerization are discussed.     

A 3.5 V, 1.3 W GaAs power multi-chip IC for cellular phones

A GaAs power multi-chip IC (MCIC) operable at a voltage of 3.5 V designed for cellular phones has been developed. The MCIC is able to deliver an output power of 1.3 W with a power-added efficiency of 60% in a frequency range from 890 to 950 MHz. This consists of two GaAs MESFET's, three GaAs passive matching chips, and a printed circuit board on which biasing networks are disposed. These are mounted on an aluminum nitride (AlN) package, occupying a half volume of conventional power hybrid IC's, i.e., only 0.4 cc. In order to improve the low voltage operation characteristics, a GaAs power MESFET operable at a low voltage of 3.5 V with an output power of 32 dBm and a power-added efficiency of 65% is developed, and microstrip lines having high impedance characteristics are incorporated also in order to minimize the conductor loss of matching network. The MCIC would be highly useful to develop compact cellular phones with advanced characteristics     

Effects of Diffuser Vane Geometry on Interaction Noise Generated from a Centrifugal Compressor

The characteristics of interaction tone noise radiated from a centrifugal compressor with a vaned diffuser are discussed by experiments, including visualization techniques using the oil-film method. Research attention is paid to the leading edge geometries of the diffuser vanes that are deeply related to the generation mechanism of the interaction tone noise. The compressor-radiated noise can be reduced by several decibels by setting some clearances in both the hub and shroud surfaces of the diffuser wall along with some decline in the pressure-rise coefficient. Since the decline turned out to be caused by the flow impingement and also by the secondary flow within the diffuser passages, several new types of diffuser vane geometries which do not detract from both the performance and noise level are developed and utilized for the experiments. The presented diffuser vane geometries will offer a few basic guidelines for the diffuser vane design.     

Nonaqueous lithium/titanium dioxide cell

The cell performance and the reaction mechanism of the Li/1 M LiClO₄ propylene carbonate/TiO₂ cell, which has an open circuit voltage of 2.85–2.90 V and 950 Wh/kg of theoretical energy density, are presented. The open circuit voltage and the working voltage exceeded the theoretical open circuit voltage (1.1 V) predicted from thermodynamic data assuming 1 electron transfer per molecule of TiO₂ and the products to be Ti₂O₃ and Li₂O. The working voltage of Li/anatase TiO₂ cell is higher than that of Li/rutile TiO₂ cell.The reaction mechanism has been shown by the electrochemical and X-ray diffractional examination to be

The self-discharge test was also done and proved the capacity loss to be negligible during a month of storage. storage.     

Low‐noise blue light generation of intracavity frequency‐doubled LD‐pumped Cr:LiSAF laser by single‐mode method

We have demonstrated the production of low‐noise blue SHG (Second Harmonic Generation) light by single‐mode oscillation in an intracavity frequency‐doubled laser diode (LD)‐pumped Cr‐doped LiSrAlF₆ (Cr:LiSAF) solid‐state laser. The SHG crystal was LiB₃O₅ (LBO). A birefringent filter and an etalon plate were used for the single‐mode Cr:LiSAF laser oscillation wave. A maximum blue SHG output power of 32 mW was obtained by using a 1‐mm‐thick birefringent filter and an etalon plate 200 μm thick with 20% reflectivity. The oscillation wavelength varied by 0.24 pm/hPa in response to changes in atmospheric pressure. A long‐term stability of 300 hours was obtained with the cavity enclosed in a barostat. © 2001 Scripta Technica, Electr Eng Jpn, 138(1): 49–55, 2002     

Image transmission through a turbulent medium using a point reflector and four-wave mixing. 2: Characteristics of the system

The characteristics of the one-way image transmission system presented in Part 1 are investigated in detail [Appl. Opt. 22, 2192 (1983)]. First, a general expression of the expectation of the transmitted image is derived for turbulence that may be typical in image transmission in the horizontal direction. Then, with the help of numerical examples, the image quality is discussed in terms of the point spread function for both thin layer and uniformly distributed turbulence. It is shown that the image transmission system is effective especially where turbulence exists relatively close to the transmission plane.