摘要:
To provide a process for producing BPDA whereby high productivity is attained while high purity is maintained.A process for producing biphenyltetracarboxylic acid dianhydride, which comprises heating biphenyltetracarboxylic acid to produce biphenyltetracarboxylic acid dianhydride, characterized in that the heating is carried out at a pressure of from 1×102 Pa to 1.1×105 Pa to a maximum temperature in a range of from 210° C. to 250° C. in such a manner that the temperature rising rate is higher than 50° C./hr for a period of at least ¼ of the time for the temperature rise from 60° C. to 210° C., and the temperature is maintained to be from 150° C. to 250° C. for from 0.5 to 10 hours.
摘要:
To provide a process for producing BPDA whereby high productivity is attained while high purity is maintained.A process for producing biphenyltetracarboxylic acid dianhydride, which comprises heating biphenyltetracarboxylic acid to produce biphenyltetracarboxylic acid dianhydride, characterized in that the heating is carried out at a pressure of from 1×102 Pa to 1.1×105 Pa to a maximum temperature in a range of from 210° C. to 250° C. in such a manner that the temperature rising rate is higher than 50° C./hr for a period of at least ¼ of the time for the temperature rise from 60° C. to 210° C., and the temperature is maintained to be from 150° C. to 250° C. for from 0.5 to 10 hours.
摘要:
To provide a process for producing BPDA whereby high productivity is attained while high purity is maintained.A process for producing biphenyltetracarboxylic acid dianhydride, which comprises heating biphenyltetracarboxylic acid to produce biphenyltetracarboxylic acid dianhydride, characterized in that the heating is carried out at a pressure of from 1×102 Pa to 1.1×105 Pa to a maximum temperature in a range of from 210° C. to 250° C. in such a manner that the temperature rising rate is higher than 50° C./hr for a period of at least ¼ of the time for the temperature rise from 60° C. to 210° C., and the temperature is maintained to be from 150° C. to 250° C. for from 0.5 to 10 hours.
摘要:
To provide a process for producing BPDA whereby high productivity is attained while high purity is maintained.A process for producing biphenyltetracarboxylic acid dianhydride, which comprises heating biphenyltetracarboxylic acid to produce biphenyltetracarboxylic acid dianhydride, characterized in that the heating is carried out at a pressure of from 1×102 Pa to 1.1×105 Pa to a maximum temperature in a range of from 210° C. to 250° C. in such a manner that the temperature rising rate is higher than 50° C./hr for a period of at least ¼ of the time for the temperature rise from 60° C. to 210° C., and the temperature is maintained to be from 150° C. to 250° C. for from 0.5 to 10 hours.
摘要:
To provide a process for producing BPDA whereby high productivity is attained while high purity is maintained.A process for producing biphenyltetracarboxylic acid dianhydride, which comprises heating biphenyltetracarboxylic acid to produce biphenyltetracarboxylic acid dianhydride, characterized in that the heating is carried out at a pressure of from 1×102 Pa to 1.1×105 Pa to a maximum temperature in a range of from 210° C. to 250° C. in such a manner that the temperature rising rate is higher than 50° C./hr for a period of at least ¼ of the time for the temperature rise from 60° C. to 210° C., and the temperature is maintained to be from 150° C. to 250° C. for from 0.5 to 10 hours.
摘要:
To provide a process for producing BPDA whereby high productivity is attained while high purity is maintained.A process for producing biphenyltetracarboxylic acid dianhydride, which comprises heating biphenyltetracarboxylic acid to produce biphenyltetracarboxylic acid dianhydride, characterized in that the heating is carried out at a pressure of from 1×102 Pa to 1.1×105 Pa to a maximum temperature in a range of from 210° C. to 250° C. in such a manner that the temperature rising rate is higher than 50° C./hr for a period of at least ¼0 of the time for the temperature rise from 60° C. to 210° C., and the temperature is maintained to be from 150° C. to 250° C. for from 0.5 to 10 hours.
摘要:
In a plasma display panel, abnormal discharge in address periods is suppressed to enhance image display quality. The scan electrode driving circuit generates a first falling down-ramp voltage i.e. down-ramp voltage L2 or down-ramp voltage L4, in initializing periods, generates sustain pulses in sustain periods, generates a rising up-ramp voltage, i.e. erasing up-ramp voltage L3, at the ends of the sustain periods, and applies the voltages to the scan electrodes. After generating the sustain pulses in the sustain periods, the scan electrode driving circuit generates a second down-ramp voltage, i.e. erasing down-ramp voltage L5, which has a portion falling with a gradient gentler than that of down-ramp voltage L2 and down-ramp voltage L4. After generating erasing down-ramp voltage L5, the scan electrode driving circuit generates erasing up-ramp voltage L3 and applies the voltage to the scan electrodes.
摘要:
An apparatus for measuring and analyzing the concentration or weight of particulates in the exhaust gas from a diesel engine. The apparatus includes a carbon particle detector which continuously measures dry soot concentration and high and low temperature HC detectors which respectively continuously measure the concentrations of gaseous hydrocarbon compounds (1) in a high-temperature undiluted state immediately upon leaving the diesel engine and (2) in a low-temperature diluted and cooled state after dilution with room air. Standard gas detectors are provided for both the high-temperature undiluted exhaust gas and the diluted and cooled exhaust gas in order to continuously determine the amount of dilution of the diluted exhaust gas. Outputs from the detectors are input to a computer to provide continuous determination of the total concentration or weight of particulates which are composed of soot particles and soluble organic fractions, as well as separate determinations of these components.
摘要:
A fluorescent gas analyzer for analyzing gases by the fluorescence method. A flashtube which is operated in its pulse mode is used as a light source. First and second optical detectors respectively detect light of a first and second wavelength range, the light of the first wavelength range being emitted by the light source and the light of the second wavelength range being emitted from a gas sample irradiated by the light source. A pair of integrators respectively integrate the outputs of the first and second detectors. Processing means, including sample and hold circuits and a synchronous detector, are used to further process the signals so that the system output is independent of deterioration of the light source and fluctuations in the strength of the light source output and independent of stray capacitance effects.
摘要:
A two-phase driving operation is performed by a first circuit and a second circuit in at least one sub-field. The first circuit applies a first ramp waveform that drops from a first potential to a second potential to a plurality of first scan electrodes in a setup period, and sequentially applies a scan pulse to the plurality of first scan electrodes in a write period. The second circuit applies a second ramp waveform that drops from the first potential to a third potential that is higher than the second potential to a plurality of second scan electrodes in the setup period, and holds the second scan electrodes at a fourth potential that is higher than the third potential in a period where the scan pulse is applied to the first scan electrodes, and then sequentially applies a scan pulse to the plurality of second electrodes in the write period. Discharge failures during write discharges can be prevented from occurring by applying the two-phase driving operation.