Abstract: The present disclosure provides a circuit and a method for improving energy harvest for an RFID tag with a temperature sensor, where an instruction command sent by a card reader includes a modulated part to invoke temperature sensor functions, and an unmodulated constant-envelop RF signal part with an extended time of duration to charge a switched additional energy storage capacitor embedded in the circuit. The switched additional energy storage capacitor is connected to the circuit upon a mode control signal corresponding to the sensor operation mode of the RFID tag. Thus, the RFID tag with the temperature sensor is ensured to conform to the timing window protocol for regular downlink operations, and at the same time, is capable of meeting higher energy demand for a high accuracy temperature sensor operation.

Abstract: The present disclosure relates to the field of analog integrated circuit technology. A digital and analog mixed signal control circuit for eliminating a degenerate metastable state of a self-biased bandgap reference circuit utilizes a digital-to-analog converter module with low-power consumption and flexibly customized accuracy as needed, a delay switch, and a non-volatile memory cell to directly control and clamp a circuit node at the degenerate metastable state in the bandgap reference circuit module, and to release the clamping after a certain delay. Such control mechanism effectively prevents the self-biased bandgap reference circuit with an operational amplifier from entering the degenerate metastable state, and enhance robustness of the circuit, such that the reference circuit is capable of starting normally under various conditions, which improves the performance and yield of the products.

Abstract: A positive feedback latch amplitude limiting control circuit and method of the passive radio frequency identification tag of the present disclosure dynamically control the voltage between the first and the second antenna terminal. When the voltage between the antenna terminals is too high, the signal generating circuit turns on the discharge circuit, which reduces the rectified DC voltage. When the voltage between the antenna terminals is within the limited voltage, the signal generating circuit turns off the discharge circuit. The discharge circuit in the present disclosure includes a MOS transistor whose gate voltage is indirectly controlled by a latch. A positive feedback mechanism of the latch makes the first control signal S1 have a substantially strong strength when being pulled to a low level, such that the discharge path is fully turned off, which avoids a discharge of the MOS transistor being in a sub-threshold region, thereby improving communication performance.

Abstract: The positive feedback latch amplitude limiting control circuit and method of the passive radio frequency identification tag of the present disclosure can dynamically rectify and control the voltage between the first antenna terminal and the second antenna terminal. When the voltage between the antenna terminals is too high, the signal generating circuit turns on the discharge circuit, such that the charges at the antenna terminal are outputted to the ground, which reduces the rectified DC voltage. When the voltage between the antenna terminals is within the limited voltage, the signal generating circuit makes the discharge circuit in the turned-off state. The rectifier circuit rectifies all the charges at the antenna terminal into DC power for the load circuit, such that the current consumption is controlled to a certain extent. The discharge circuit in the present disclosure includes a MOS transistor whose gate voltage is indirectly controlled by a latch.

Abstract: The present disclosure relates to the field of analog integrated circuit technology. A digital and analog mixed signal control circuit for eliminating a degenerate metastable state of a self-biased bandgap reference circuit utilizes a digital-to-analog converter module with low-power consumption and flexibly customized accuracy as needed, a delay switch, and a non-volatile memory cell to directly control and clamp a circuit node at the degenerate metastable state in the bandgap reference circuit module, and to release the clamping after a certain delay. Such control mechanism effectively prevents the self-biased bandgap reference circuit with an operational amplifier from entering the degenerate metastable state, and enhance robustness of the circuit, such that the reference circuit is capable of starting normally under various conditions, which improves the performance and yield of the products.

Abstract: The present disclosure provides a circuit and a method for improving energy harvest for an RFID tag with a temperature sensor, where an instruction command sent by a card reader includes a modulated part to invoke temperature sensor functions, and an unmodulated constant-envelop RF signal part with an extended time of duration to charge a switched additional energy storage capacitor embedded in the circuit. The switched additional energy storage capacitor is connected to the circuit upon a mode control signal corresponding to the sensor operation mode of the RFID tag. Thus, the RFID tag with the temperature sensor is ensured to conform to the timing window protocol for regular downlink operations, and at the same time, is capable of meeting higher energy demand for a high accuracy temperature sensor operation.

Abstract: The present invention discloses an aspartase variant, method of preparing the same and use thereof. Compared with sequence 2 in the sequence listing, the amino acid sequence of the aspartase variant provided in the present invention has more than 96% identity, and there are mutations in T187I and N326C at positions 187 and 326, respectively, and has improved catalytic activity for the ammoniation of acrylic acid, compared with the aspartase shown in sequence 2. The experiment proves that the aspartase variant provided in the present invention does have improved catalytic activity for the ammoniation of acrylic acid compared with the wild type parent aspartase, and has better thermal stability and pH spectrum. The reaction can greatly increase the conversion ratio of acrylic acid.

Abstract: An oscillation maintenance circuit with comparator-based pulse generation is provided. By sampling an RF signal and controlling a pulse generation circuit to generate a pulse signal of the same frequency as the RF signal, a switch unit is controlled to be ON/OFF at a same frequency as the RF signal, achieving synchronization between change of the current injection and the RF signal. Thus, the oscillation frequency is not affected by current injection, ensuring the FSK communication performance. At the same time, two comparators are respectively compared with two reference voltage levels to obtain an output pulse signal, and the reference voltage levels can be adjusted according to practical requirements, so that the switch-on point of time and current injection time duration are adjustable, maximizing the efficiency of current injection, resulting in simple circuit structure, low power consumption, and increased communication distance of an HDX passive RFID transponder.

Abstract: The present invention discloses an aspartase variant, method of preparing the same and use thereof. Compared with sequence 2 in the sequence listing, the amino acid sequence of the aspartase variant provided in the present invention has more than 96% identity, and there are mutations in T187I and N326C at positions 187 and 326, respectively, and has improved catalytic activity for the ammoniation of acrylic acid, compared with the aspartase shown in sequence 2. The experiment proves that the aspartase variant provided in the present invention does have improved catalytic activity for the ammoniation of acrylic acid compared with the wild type parent aspartase, and has better thermal stability and pH spectrum. The reaction can greatly increase the conversion ratio of acrylic acid.

Abstract: A half-duplex RFID oscillation maintenance circuit with trigger-based pulse generation is provided, including: a resonance inductor and a resonance capacitor forming an L-C resonance circuit coupled to an external radio frequency field to generate alternating current for a rectifier circuit, which is connected to an energy-storage capacitor. A first antenna end is connected to a trigger circuit through a switch unit and a resistor connected in series; and an output end of the trigger circuit is connected to a control end of the switch unit. The trigger circuit is configured to sample an oscillation signal at the first antenna end to generate a rectangular wave signal, whose pulse width can be self-adaptively adjusted, to control OFF/ON of the switch unit and, when the switch unit is ON, to form a current injection loop from the energy-storage capacitor to the L-C resonance circuit.

Abstract: A half-duplex RFID oscillation maintenance circuit with trigger-based pulse generation is provided, including: a resonance inductor and a resonance capacitor forming an L-C resonance circuit coupled to an external radio frequency field to generate alternating current for a rectifier circuit, which is connected to an energy-storage capacitor. A first antenna end is connected to a trigger circuit through a switch unit and a resistor connected in series; and an output end of the trigger circuit is connected to a control end of the switch unit. The trigger circuit is configured to sample an oscillation signal at the first antenna end to generate a rectangular wave signal, whose pulse width can be self-adaptively adjusted, to control OFF/ON of the switch unit and, when the switch unit is ON, to form a current injection loop from the energy-storage capacitor to the L-C resonance circuit.

Abstract: The present invention relates to the technical field of radio frequency identification, in particular to a rectifier and limiter circuit controlled by switching signals and a passive radio frequency tag comprising the rectifier and limiter circuit. The rectifier and limiter circuit controlled by switching signals provided by the present invention converts DC signals, which are absorbed and rectified by an inductance coil antenna of a passive RFID tag, into high- and low-level signals and inputs the high- and low-level signals into the control input terminals of discharge paths of a rectifier circuit. The discharge paths are controlled to be opened or closed according to the amount of charge. The amplitude limiting control of the circuit voltage is realized by dynamically adjusting the voltage amplitude of a rectifier, thereby meeting the requirements on reliability of over-voltage protection of a semiconductor device on a chip and avoiding saturation of reception at the card reader side.

Abstract: An oscillation maintenance circuit with comparator-based pulse generation is provided. By sampling an RF signal and controlling a pulse generation circuit to generate a pulse signal of the same frequency as the RF signal, a switch unit is controlled to be ON/OFF at a same frequency as the RF signal, achieving synchronization between change of the current injection and the RF signal. Thus, the oscillation frequency is not affected by current injection, ensuring the FSK communication performance. At the same time, two comparators are respectively compared with two reference voltage levels to obtain an output pulse signal, and the reference voltage levels can be adjusted according to practical requirements, so that the switch-on point of time and current injection time duration are adjustable, maximizing the efficiency of current injection, resulting in simple circuit structure, low power consumption, and increased communication distance of an HDX passive RFID transponder.

Abstract: A time domain integrated temperature sensor described by the present invention adopts a shaped clock signal to control the charging time of capacitors, so that the capacitors generate charging time delay signals related to the cycle of an input clock, and a pulse signal related to pulse width, temperature and the cycle of the input clock is generated through logical XOR (Exclusive OR) operation on a time delay signal generated when the capacitors are charged by one way of PTAT (Proportional To Absolute Temperature) current in an above control manner and a time delay signal generated when the capacitors are charged by one way of CTAT (Complementary To Absolute Temperature) current in the same manner; then, the same input clock signal is adopted for quantifying the pulse width of the pulse signal, the relevance of the obtained quantization result and the cycle of the input clock is completely offset, namely, an output value of the temperature sensor is unrelated to the input clock signal, thereby solving the pr

Abstract: The invention relates to a method for enzymatically synthesizing an (oligo)peptide, comprising coupling (a) an (oligo)peptide C-terminal ester or thioester and (b) an (oligo)peptide nucleophile having an N-terminally unprotected amine, wherein the coupling is carried out in a fluid comprising water, and wherein the coupling is catalyzed by a subtilisin BPN? variant or a homolog thereof, which comprises the following mutations compared to subtilisin BPN? represented by SEQUENCE ID NO: 2 or a homolog sequence thereof: a deletion of the amino acids corresponding to positions 75-83; a mutation at the amino acid position corresponding to S221, the mutation being S221C or S221 selenocysteine; preferably a mutation at the amino acid position corresponding to P225 wherein the amino acid positions are defined according to the sequence of subtilisin BPN? represented by SEQUENCE ID NO: 2. Further, the invention relates to an enzyme suitable for use as a catalyst in a method of the invention.

Abstract: The invention relates to a method for enzymatically synthesizing an (oligo)peptide, comprising coupling (a) an (oligo)peptide C-terminal ester or thioester and (b) an (oligo)peptide nucleophile having an N-terminally unprotected amine, wherein the coupling is carried out in a fluid comprising water, and wherein the coupling is catalyzed by a subtilisin BPN? variant or a homologue thereof, which comprises the following mutations compared to subtilisin BPN? represented by SEQUENCE ID NO: 2 or a homologue sequence thereof : a deletion of the amino acids corresponding to positions 75-83; a mutation at the amino acid position corresponding to S221, the mutation being S221C or S221 selenocysteine; preferably a mutation at the amino acid position corresponding to P225 wherein the amino acid positions are defined according to the sequence of subtilisin BPN? represented by SEQUENCE ID NO: 2. Further, the invention relates to an enzyme suitable for use as a catalyst in a method of the invention.

Abstract: The present invention discloses a radio-frequency (RF) front-end circuit combining functions of rectification and load modulation and a passive RF tag including thereof. The RF front-end circuit includes a first modulation unit arranged at an output of a rectifier circuit and a second modulation unit arranged between a first and a second end of an antenna coil. The first modulation unit and the second modulation unit are configured to change respectively the voltage at the output of the rectifier circuit and voltage at the two ends of the antenna coil by modulating under a strong field environment or a weak field environment, thus adjusting modulation depth of the passive RF tag. The RF front-end circuit also includes a unidirectional conducting unit to prevent loss of charges stored in a capacitor. The present invention solves existing contradiction of design specification requirements between cost and sensitivity of a passive RF tag.

Abstract: The invention relates to a method for enzymatically synthesizing an (oligo)peptide, comprising coupling (a) an (oligo)peptide C-terminal ester or thioester and (b) an (oligo)peptide nucleophile having an N-terminally unprotected amine, wherein the coupling is carried out in a fluid comprising water, and wherein the coupling is catalyzed by a subtilisin BPN? variant or a homo-log thereof, which comprises the following mutations compared to subtilisin BPN? represented by SEQUENCE ID NO: 2 or a homolog sequence thereof: a deletion of the amino acids corresponding to positions 75-83; a mutation at the amino acid position corresponding to S221, the mutation being S221C or S221 selenocysteine; preferably a mutation at the amino acid position corresponding to P225 wherein the amino acid positions are defined according to the sequence of subtilisin BPN? represented by SEQUENCE ID NO: 2. Further, the invention relates to an enzyme suitable for use as a catalyst in a method of the invention.

Abstract: The present invention discloses a radio-frequency (RF) front-end circuit combining functions of rectification and load modulation and a passive RF tag including thereof. The RF front-end circuit includes a first modulation unit arranged at an output of a rectifier circuit and a second modulation unit arranged between a first and a second end of an antenna coil. The first modulation unit and the second modulation unit are configured to change respectively the voltage at the output of the rectifier circuit and voltage at the two ends of the antenna coil by modulating under a strong field environment or a weak field environment, thus adjusting modulation depth of the passive RF tag. The RF front-end circuit also includes a unidirectional conducting unit to prevent loss of charges stored in a capacitor. The present invention solves existing contradiction of design specification requirements between cost and sensitivity of a passive RF tag.

Abstract: The present invention relates to the field of radio frequency identification, in particular to a temperature measurement and calibration circuit and a passive radio frequency identification tag. Meanwhile, the present invention further relates to a method for performing temperature measurement by using the tag. The temperature measurement and calibration circuit of the tag generates an upper reference voltage value limit and a lower reference voltage value limit, which do not change with temperature, then calibrates the upper reference voltage value limit and the lower reference voltage value limit to a uniform upper voltage value limit and a uniform lower voltage value limit, and eliminates the problem of different reference voltages of tags due to the power supply voltage fluctuation and process deviation. Meanwhile, a temperature measurement voltage generator circuit of the tag generates a calibration voltage value under a uniform calibration temperature.