摘要:
An exemplary bridge includes an arch unit. The arch unit includes a first abutment and a second abutment, a deck extending between the first and second abutments, a pair of asymmetrical arches, and a plurality of suspender members 3 attached between the arches and the deck. The first and second abutments are spaced apart from each other at a predetermined distance. The asymmetrical arches are juxtaposedly arranged between and supported by the first and second abutments. Each of the asymmetrical arches includes a first arch foot portion mounted on the first abutment, a parabolic portion proximate to the first arch foot portion, a catenary portion proximate to the parabolic portion, and a second arch foot portion proximate to the catenary portion mounted on the second abutment.
摘要:
Wireless data services such as wireless email are becoming common, and in particular, “always-on” systems, where new email is automatically forwarded by the service provider to the wireless device. The problem is that there is no effective mechanism for implementing “always-on” systems when the user is moving around a network, or from one network to another. The invention addresses this problem by generating a session key at the service provider's system for a given data session, and returning this session key to the mobile device. Each time the mobile device communicates with the service provider, it enters this session key into a field that will simply pass through the communication network to the service provider. This allows the service provider to manage the data session, preparing proper accounting records and directing the deletion of stale data sessions on network resources.
摘要:
Embodiments of the present invention relate to a separate type mass data encryption/decryption apparatus and an implementing method therefor. The separate type mass data encryption/decryption apparatus includes a microprocessor and a storage unit for storing an encryption/decryption key. The apparatus further includes an external communication interface module connecting to a peripheral data bus for transmitting data between the encryption/decryption apparatus and an external terminal, and said microprocessor is used for encrypting/decrypting data inputted from the external terminal. Embodiments of the present invention can process mass data with higher security and expedience.
摘要:
A portable electronic device (80) has a battery cover (100) and a housing (300) releasably mounted with a battery cover latching assembly (200). The battery cover has a receiving hole (114). The housing has a positioning member (316). The battery cover latching assembly includes a latching member (201) and a resilient member (202). The latching member has a locking portion (2019). The resilient member has a first end (2021) and a second end (2022). The first end is mounted in the latching member. The second end is mounted with the battery cover. The latching member is installed in the receiving hole. The locking portion is engaged with the positioning member thereby mounting the battery cover to the housing. When the latching member is forced to move relative to the battery cover, the resilient member is twisted thereby making the latching member to move in an opposing direction.
摘要:
A proton conductor, a method for manufacturing the same, and an electrochemical device using the proton conductor are provided. The proton conductor includes a carbon derivative which has a carbon material selected from the group consisting of a fullerene molecule, a cluster consisting essentially of carbon, a fiber-shaped carbon anPlease do not hesitate to contact us with any questions d a tube-regarding this matter shaped carbon, and mixtures thereof, and at least a proton dissociative group, the proton dissociative group being bonded to the carbon material via a cyclic structure of tricyclic or more. The method includes the steps of obtaining the carbon derivative, hydrolyzing the derivative with alkali hydroxide, subjecting the hydrolyzed product to ion exchange, and forming a group with proton-dissociating properties.
摘要:
A gate driver for a power switch, comprising a gate drive circuit coupled to the gate of the power switch for at least one of turning on and turning off the power switch; a gate voltage control circuit in the gate drive circuit for controlling a voltage applied to the gate of the power switch during at least one of turning on and turning off the power switch; and a signal supplied to the gate voltage control circuit indicative of a voltage rate of change per unit time to be applied in at least one of turning on and turning off the power switch.
摘要:
A circuit for providing power factor correction includes a bridgeless boost converter circuit and a control circuit receiving an input AC line voltage of the bridgeless boost converter circuit, wherein the control circuit provides a pulse width modulated signal to control the on time of a PFC switch of the bridgeless boost converter circuit. The control circuit also includes a scaling device operable to scale down a bi-polar AC voltage of the input AC line voltage to a uni-polar AC voltage, an analog to digital converter operable to convert the uni-polar AC voltage into digital data and a digital rectifier operable to process the digital data of the uni-polar AC voltage to provide a half-sinusoidal AC signal that is proportional to and in phase with the input AC line voltage for use in providing the pulse width modulated signal.
摘要:
A circuit for providing power factor correction includes a boost converter circuit with a boost inductance and a power factor correction switch and a control circuit. The control circuit provides a pulse width modulated signal to control the on time of a PFC switch, and also includes a power factor correction pulse width modulated device receiving as inputs a rectified AC input voltage, a DC bus voltage, a signal proportional to the current through the inductor and a reference current signal. The power factor correction pulse width modulated device also includes a pulse width modulated generator operable to provide the pulse width modulated signal to control the on time of the PFC circuit and a pulse width modulated blanking device operable to provide an enable/disable signal to disable the pulse width modulated generator when predetermined conditions are met.
摘要:
A circuit for providing power factor correction comprising a boost converter circuit having a boost inductance and a power factor correction switch coupled in series with the boost inductance, the boost inductance and power factor correction switch being coupled across the output of a rectifier being supplied with AC power from an AC line, the boost converter circuit further comprising a boost diode coupled to a junction between the inductor and the switch, an output of the boost diode coupled to an output capacitor, a DC bus voltage being provided across the output capacitor, further comprising a control circuit receiving as inputs a rectified AC input voltage from the rectifier, a signal proportional to current through the inductor and the DC bus voltage across the capacitor, and wherein the control circuit provides a pulse width modulated signal to control the on time of the PFC switch, further comprising an enable/disable circuit receiving as inputs the rectified AC input voltage and the DC bus voltage, the circuit instantaneously comparing the rectified AC input voltage and the DC bus voltage and controlling the control circuit whereby the control circuit provides the pulse width modulated signal to control the PFC switch when the rectified AC input voltage is less than the DC bus voltage and disables the generation of the pulse width modulated signal to the PFC switch when the rectified AC input voltage is greater than DC bus voltage.
摘要:
A digital power control system provides an optimal solution to power supply. The digital power control systems comprises a direct current (DC) power supply; a state configuring device generating a plurality of state signals; a pulse generator connected to the state configuring device, converting the state signals to a plurality of waveform signals; a driving device connected to the DC power supply and the state configuring device respectively, and outputting a driving voltage according to the waveform signal; a transformer connected to the driving device, transforming the driving voltage to an AC operating voltage; and an alternating current (AC) load connected to the transformer; a feedback circuit connected to the AC load; a power detector connected to the feedback circuit for detecting the output power of the AC load, and optimizing the output power by adjusting the waveform signal outputted by the pulse generator.