Abstract: A method for removing a heavy metal from water includes subjecting a microbial solution containing a liquid culture of a urease-producing bacterial strain and a reaction solution containing a manganese compound and urea to a microbial-induced precipitation reaction, so as to obtain biomineralized manganese carbonate (MnCO3) particles, admixing the biomineralized MnCO3 particles with water containing a heavy metal, so that the biomineralized MnCO3 particles adsorb the heavy metal in the water to form a precipitate, and removing the precipitate from the water.

Abstract: An overvoltage protection circuit protects a portable electronic device against overvoltage. The overvoltage protection circuit includes an input unit for receiving an input voltage supplied by a voltage source; a voltage-divider module for dividing the input voltage and outputting a divided voltage; a voltage-regulator module for comparing a comparison voltage with the divided voltage and generating a first control signal; a first switch unit being controllably switched by the first control signal to a short-circuit state or an open-circuit state and generating a second control signal; and a second switch unit being controllably switched by the second control signal to a circuit state reverse to that of the first switch unit, and stopping supplying the input voltage to the portable electronic device when the input voltage is no less than a rated voltage of the portable electronic device. Therefore, a temperature-independent overvoltage protection can be achieved.

Abstract: A UART interface communication circuit includes a plurality of communication devices, and each includes a UART interface, a selecting apparatus, a CPU, and a multiplexer (MUX). The communication devices connect with each other via the UART interfaces thereof. The selecting apparatus is connected to the CPU for defining one of the communication devices as a master communication device and the rest as slave communication devices. The MUX is connected between the UART interface and the CPU. When the master communication device transmits data carrying an ID to the slave communication devices, a slave communication device corresponding to the ID receives and processes the data, and transmits return data to the master communication device, and then the MUX receives the return data from the slave communication device and passes it to the CPU of the master communication device for processing.

Abstract: A UART interface communication circuit includes a plurality of communication devices, and each includes a UART interface, a selecting apparatus, a CPU, and a multiplexer (MUX). The communication devices connect with each other via the UART interfaces thereof. The selecting apparatus is connected to the CPU for defining one of the communication devices as a master communication device and the rest as slave communication devices. The MUX is connected between the UART interface and the CPU. When the master communication device transmits data carrying an ID to the slave communication devices, a slave communication device corresponding to the ID receives and processes the data, and transmits return data to the master communication device, and then the MUX receives the return data from the slave communication device and passes it to the CPU of the master communication device for processing.