Generalized concatenated codes for channels where unidirectionalbyte errors are predominant

Codes are considered for correction and detection of unidirectional byte errors. A code construction based on the generalized concatenated code construction is proposed. This construction gives a large number of efficient codes. For example, from this construction, a 72-input-bit encoder of the triple unidirectional 8-bit-byte error-correcting and fourfold unidirectional 8-bit-byte error-detecting code with a length of 112 bits and rate 9/14 is obtained, whereas the ordinary triple 8-bit-byte error-correcting and fourfold 8-bit-byte error-detecting code of the same length has only 56 information bits and is of rate 1/2. The proposed construction is generalized to one that gives efficient short-length codes     

Extracorporeal shock wave lithotripsy on patients with spinal cord injury with special reference to autonomic hyperreflexia

We performed treatment of urolithiasis on 7 patients with spinal cord injury (6 males and one female, with a mean age of 41 years old) by extracorporeal shock wave lithotripsy (ESWL) using a Lithostar (Siemens). The level of injury was cervical in 3 patients and lower thoracic in 4. The treated stones were renal in 6 patients, including one staghorn caliculus, ureteral in 2, and bladder stones in 2 patients. ESWL was performed under general anesthesia in 2 patients, and in another patient, epidural anaesthesia was employed in the first several sessions, but thereafter treatment was safely continued with no anesthesia. The other 4 patients were treated without anesthesia. In most patients, the stones (9 stones in 6 cases) were easily disintegrated after treatment of from one to 14 sessions, except one case of staghorn caliculus, and the clearance of fragments was also satisfactory. In one patient, hypertension and bradycardia due to autonomic hyperreflexia were observed during ESWL, and the treatment was discontinued, but the stone was successfully disintegrated and the fragments were voided. In another patient, autonomic hyperreflexia was observed while the fragments passed through the ureter, although no signs of this reflexia were seen during the ESWL procedure.     

New chemical etching solution for InP and GaInAsP gratings

A new chemical etching solution of bromine-water system, which is suitable for transforming the fine resist grating mask pattern onto InP and GaInAsP surfaces, is reported. The Br2:H2O:H3PO4 (or HCl) solution does not dissolve AZ 1350 photoresist and exhibits both moderate etching rate and a pit-free etched surface.     

Fabry-Perot cavity type 1.5 ?m InGaAsP BH-laser amplifier with small optical-mode confinement

A 1.5 ?m InGaAsP buried-heterostructure laser amplifier having small optical-mode confinement was fabricated with a Fabry-Perot cavity configuration. Its signal gain, saturation output power and noise characteristics were studied and found to be superior to those for AlGaAs amplifiers, as a result of small optical-mode confinement.     

Application of tritium radioluminography to the detection of hydrogen diffusion in Ti-Cr alloy

Tritium radioluminography has been applied to determine the hydrogen (H) diffusion coefficients in Ti₅₀Cr₅₀ and Ti₄₀Cr₆₀ alloys, both with two-phase structures of a body-centered cubic (bcc) phase and a Laves phase. Using radioluminography, H distributions in those phases have been observed, and H penetration profiles have been measured. The tritium diffusion coefficients in the Ti₅₀Cr₅₀ and Ti₄₀Cr₆₀ alloys have been successfully determined by analyzing the tritium penetration profiles to be 3.3±0.3 × 10^?12 and 1.4±0.1×10^?12 m²/s, respectively. These values suggest that the H diffusion in the Laves phase is slower than that in the bcc phase. It is also suggested that H diffuses by short-circuiting diffusion through the interface between the bcc phase and the Laves phase.