摘要:
A driver for driving a driving element includes: a signal source, for providing a square signal; a first modulation circuit, for providing on-pulses and off-pulses according to edges of the square signal; a transformer for coupling output signals of the first modulation circuit to a secondary winding of the transformer to form coupled signals; a second modulation circuit for providing first operating pulses according to coupled on-pulses of the coupled signals, and providing second operating pulses according to coupled off-pulses of the coupled signals; a switch device for turning off the switch device according to the first operating pulses and turning on the switch device according to the second operating pulses, and when the switch device is turned off, coupled on-pulses charge an equivalent capacitor of the driving element to a first driving potential to turn on the driving element, and when the switch device is turned off, the equivalent capacitor discharges to a second driving potential to turn off the driving element, and the width of the on-pulses is less than 1000 ns.
摘要:
A patient interface gas delivery mask having a forehead and chin support system including a forehead support, a chin support, and a system for supplying a flow of gas to a patient that incorporates such a mask, forehead support, and chin support. The forehead support includes a supporting arm which is adjustably mounted to the mask shell, thereby allowing the adjustment of the distance between the forehead support bracket and the mask shell in order to adjust for patient's of different sizes. A forehead support bracket is pivotally connected to the support arm. Likewise the chin support is also adjustably mounted to the mask shell.
摘要:
Yield, particularly when treating hardwood chips, can be improved by at least 1-2% in a kraft cellulose pulping process by keeping the temperature and effective alkali (EA) low during impregnation, and by keeping the EA low in at least a first cook stage. After cooking, the pulp is subjected to cooling low EA liquor, e.g. to reduce its temperature to below 120° C. (preferably below 100° C.) with an EA below about 5 g/L (expressed as NaOH). Continuous treatment in a continuous digester system is preferred, with the EA below about 20 g/L during impregnation and the first cook.
摘要:
The invention provides a novel polyisocyanate compound which is useful as a starting material for an optical material having a high refractive index, a low dispersion and excellent optical characteristics, and a process for producing this compound at good efficiency. The invention also provides an optical material having a high refractive index, a low dispersion, an excellent transparency without optical distortion and having good heat resistance.
摘要:
A process for producing a polythiol oligomer having disulfide linkages by reacting polythiol (with the functionality of two or above) with sulfur in a molar ratio of m to (m-1) (where m is an integer of 2 to 21) in the presence of a basic catalyst, whereby the oligomers produced have a degree of oligomerization of m (wherein m is defined as above). Specifically disclosed is a process for reacting 2,5-dimercaptomethyl-1,4-dithiane (DMMD) with sulfur in a molar ratio 2:1 or 3:2 in the presence of a basic catalyst, thereby producing an oligomer represented by the below formula: ##STR1## (wherein n is an integer of up to 21). Also disclosed are optical polymers made with the oligomer and optical materials and devices made with the polymer.
摘要:
The present invention discloses a power supply. The power supply may comprise an input power terminal, a capacitor module, a first converter module and a second converter module. The first converter module may have a first terminal and a second terminal, wherein the first terminal is coupled to the input power terminal and the second terminal is coupled to the capacitor module. The second converter module may comprise an input and an output, wherein the input of the second converter module is coupled to the input power terminal, and the output of the second converter module is configured to supply a load.
摘要:
The present invention discloses a power supply. The power supply may comprise an input power terminal, a capacitor module, a first converter module and a second converter module. The first converter module may have a first terminal and a second terminal, wherein the first terminal is coupled to the input power terminal and the second terminal is coupled to the capacitor module. The second converter module may comprise an input and an output, wherein the input of the second converter module is coupled to the input power terminal, and the output of the second converter module is configured to supply a load.
摘要:
According to one aspect, a computerized method and apparatus for generating and presenting search snippets that enable user-directed navigation of the underlying audio/video content. The method involves obtaining metadata associated with discrete media content that satisfies a search query. The metadata identifies a number of content segments and corresponding timing information derived from the underlying media content using one or more automated media processing techniques. Using the timing information identified in the metadata, a search result or “snippet” can be generated that enables a user to arbitrarily select and commence playback of the underlying media content at any of the individual content segments.
摘要:
A method for converting a signal from a low voltage domain to a high voltage domain includes receiving an input signal in a low voltage domain, and using the input signal, controlling a first transistor having a first carrier type, a second transistor having a second carrier type different from the first carrier type, and a third transistor having the second carrier type to produce an output voltage at an output terminal. The first transistor is coupled to the output terminal and further coupled to a first voltage corresponding to a first value in a high voltage domain. The second and third transistors are coupled in series between the output terminal and a second voltage corresponding to a second value in the high voltage domain. The output voltage is selected to correspond to either the first voltage or the second voltage based upon the input signal.
摘要:
The present invention discloses forward power converter. The power converter includes a transformer for transferring an input voltage from a primary side to a secondary side. The secondary side includes a main output voltage loop and at least one auxiliary output loop connected with a magnetic amplifier. A pulse width modulation (PWM) controller controls a switch on the primary side of the transformer for turning on the switch and turning off the main output voltage loop and the auxiliary output voltage loop for storing a magnetizing energy on windings of the secondary side. The magnetic amplifier includes a first and a second magnetization windings controlled by a first and a second control circuits respectively for providing a positive and negative magnetization current to carrying out a bi-directional magnetization process to achieve expanded load range operable for the forward power converter.