Abstract: A method for manufacturing a surface-treated gas-phase-process silica particle, the method including steps of: adding 1,3-divinyl-1,1,3,3-tetramethyldisilazane to a raw material gas-phase-process silica particle and introducing a vinyldimethylsilyl group on a surface of the raw material gas-phase-process silica particle to obtain a preliminarily treated silica particle; and adding hexamethyldisilazane to the preliminarily treated silica particle and introducing a trimethylsilyl group on a surface of the preliminarily treated silica particle to obtain a surface-treated gas-phase-process silica particle.

Abstract: A synthetic quartz glass substrate having a controlled hydrogen molecule concentration is prepared by (a) hot shaping a synthetic quartz glass ingot into a glass block, (b) slicing the glass block into a glass plate, (c) annealing the glass plate at 500-1,250° C. for 15-60 hours, (d) hydrogen doping treatment of the glass plate in a hydrogen gas atmosphere at 300-450° C. for 20-40 hours, and (e) dehydrogenation treatment of the glass plate at 200-400° C. for 5-10 hours.

Abstract: A synthetic quartz glass substrate is prepared by furnishing a synthetic quartz glass block, coating an arbitrary surface and an opposite surface of the block with a liquid having a transmittance of at least 99.0%/mm at the wavelength of birefringence measurement, measuring the birefringence of the block by letting light enter one coated surface and exit the other coated surface, and sorting the block to an acceptable or unacceptable group, based on the measured birefringence value.

Abstract: A synthetic quartz glass substrate is prepared by furnishing a synthetic quartz glass block, coating two opposite surfaces of the block with a liquid having a transmittance of at least 99.0%/mm at the wavelength of birefringence measurement, measuring a birefringence distribution on the block by letting light enter one coated surface and exit the other coated surface, and sorting the block to an acceptable group or unacceptable group, based on the measured birefringence distribution.

Abstract: A synthetic quartz glass substrate having a controlled hydrogen molecule concentration is prepared by (a) hot shaping a synthetic quartz glass ingot into a glass block, (b) slicing the glass block into a glass plate, (c) annealing the glass plate at 500-1,250° C. for 15-60 hours, (d) hydrogen doping treatment of the glass plate in a hydrogen gas atmosphere at 300-450° C. for 20-40 hours, and (e) dehydrogenation treatment of the glass plate at 200-400° C. for 5-10 hours.

Abstract: A synthetic quartz glass substrate is prepared by furnishing a synthetic quartz glass block, coating two opposite surfaces of the block with a liquid having a transmittance of at least 99.0%/mm at the wavelength of birefringence measurement, measuring a birefringence distribution on the block by letting light enter one coated surface and exit the other coated surface, and sorting the block to an acceptable group or unacceptable group, based on the measured birefringence distribution.

Abstract: A method for heat treating a synthetic quartz glass having a hydroxyl concentration with a maximum/minimum difference (?OH) of less than 350 ppm involves the steps of first heat treatment of holding at 1,150-1,060° C. for a time of 0.5-10 hours, cooling down to a second heat treatment temperature at a rate of ?7° C./hr to ?30° C./hr, second heat treatment of holding at 1,030-950° C. for a time of 5-20 hours, and annealing at a rate of ?25° C./hr to ?85° C./hr. Two stages of heat treatment ensures that the glass has a low birefringence.

Abstract: A synthetic quartz glass substrate is prepared by furnishing a synthetic quartz glass block, coating an arbitrary surface and an opposite surface of the block with a liquid having a transmittance of at least 99.0%/mm at the wavelength of birefringence measurement, measuring the birefringence of the block by letting light enter one coated surface and exit the other coated surface, and sorting the block to an acceptable or unacceptable group, based on the measured birefringence value.

Abstract: A method for heat treating a synthetic quartz glass having a hydroxyl concentration with a maximum/minimum difference (?OH) of less than 350 ppm involves the steps of first heat treatment of holding at 1,150-1,060° C. for a time of 0.5-10 hours, cooling down to a second heat treatment temperature at a rate of ?7° C./hr to ?30° C./hr, second heat treatment of holding at 1,030-950° C. for a time of 5-20 hours, and annealing at a rate of ?25° C./hr to ?85° C./hr. Two stages of heat treatment ensures that the glass has a low birefringence.

Abstract: A multiline telephone apparatus with caller ID signal detecting function had an expensive modem for demodulating the caller ID in each one of telephone lines. According to the invention of the present application, each line is provided with a signal detecting circuit for detecting a channel seizure signal or carrier signal in the caller ID signal, and the input line to the modem for caller ID demodulation is changed over depending on the detection output of these signal detecting circuits, so that the caller ID signals of a plurality of lines can be demodulated by one modem only. As a result, a simple and inexpensive multiline telephone apparatus with caller ID signal detecting function is realized.

Abstract: In addition to the conventional telephone portion, this telephone apparatus, coupled to a subscriber's (TEL) line coupled to an intercommunication (ICM) line, comprises a modulation circuit for modulating a data signal to have a frq band different from that used in the conventional telephone portion; a demodulation circuit for receiving/demodulating a modulated data signal having that frq band from another telephone apparatus connected to the same ICM line; and a control circuit for effecting communication with the TEL line and generating control data indicative of inhibition of using the TEL line and transmitting it as the data signal toward another telephone apparatus when the user responds a call or demodulation circuit does not receive modulated data signal indicative of inhibition of using the TEL line from another telephone apparatus. A busy tone may be supplied to the user when the user tries to use the TEL line if the control data is received by the demodulation circuit.

Abstract: A digital audio tape recorder and a method for operating the same, especially in a music program jump selecting mode. In one embodiment, the state of an erasure-preventing tab is detected, and TOC (Table-Of-Contents) information is transferred from the tape to a TOC information memory only when the erasure-preventing tab is set to an indicate an unrecordable state. In accordance with another embodiment, when the music program number of the music selection presently being reproduced is known and the program number is aligned, a target music program number is calculated and displayed.

Abstract: A digital audio tape recorder and a method for operating the same, especially in a music program jump selecting mode. In one embodiment, the state of an erasure-preventing tab is detected, and TOC (Table-Of-Contents) information is transferred from the tape to a TOC information memory only when the erasure-preventing tab is set to an indicate an unrecordable state. In accordance with another embodiment, when the music program number of the music selection presently being reproduced is known and the program number is aligned, a target music program number is calculated and displayed.