Abstract: An engine includes a cylinder head and a cylinder block. The cylinder head has a first water jacket passage, an exhaust passage and a second water jacket passage. The exhaust passage is located between the first water jacket passage and the second water jacket passage. The first water jacket passage and the second water jacket passage are disposed close to the exhaust passage. The first water jacket passage is in communication with the second water jacket passage. The second water jacket passage is in communication with the cylinder block. The second water jacket passage has a water inlet passage.

Abstract: Embodiments of this application disclose a head-mounted wireless headset and a communication method thereof, and relate to the communication field. A specific solution is as follows: The head-mounted wireless headset includes: a first headphone, including: a first short-range wireless communication chip and a first radio frequency antenna, where the first short-range wireless communication chip is coupled to the first radio frequency antenna; a second headphone, including: a second short-range wireless communication chip and a second radio frequency antenna, where the second short-range wireless communication chip is coupled to the second radio frequency antenna; and a data bus, separately connected to the first short-range wireless communication chip and the second short-range wireless communication chip, and configured to provide a physical link required for communication between the first short-range wireless communication chip and the second short-range wireless communication chip.

Abstract: A photovoltaic energy system and a method for detecting a ground insulation impedance, improve accuracy of detecting a ground insulation impedance after one or more conversion circuits are connected in parallel. The photovoltaic energy system includes one or more conversion circuits and a detection circuit. The detection circuit includes an alternating current signal source and a sampling resistor that are connected in series, a first sampling circuit, and a control circuit. The control circuit is configured to control the alternating current signal source to output harmonic signals of a first frequency and a second frequency. The first sampling circuit is configured to: when the alternating current signal source outputs the harmonic signal of the first frequency, collect a voltage at both terminals of the sampling resistor to obtain a first voltage.

Abstract: A photovoltaic energy system and a method for detecting a ground insulation impedance, improve accuracy of detecting a ground insulation impedance after one or more conversion circuits are connected in parallel. The photovoltaic energy system includes one or more conversion circuits and a detection circuit. The detection circuit includes an alternating current signal source and a sampling resistor that are connected in series, a first sampling circuit, and a control circuit. The control circuit is configured to control the alternating current signal source to output harmonic signals of a first frequency and a second frequency. The first sampling circuit is configured to: when the alternating current signal source outputs the harmonic signal of the first frequency, collect a voltage at both terminals of the sampling resistor to obtain a first voltage.

Abstract: A circuit for arc detection in a direct current and a microprocessor to resolve a problem of low accuracy of a detection result of an existing circuit for arc detection in a direct current, where the circuit includes a current sampling circuit, a first circuit, a second circuit, and a microprocessor. The current sampling circuit is configured to perform current sampling on the direct current, and output a current sampling signal of the direct current. The first circuit is configured to output a time domain signal including at least one pulse. The second circuit is configured to output a frequency domain signal of the current sampling signal after amplifying and filtering the current sampling signal. The microprocessor is configured to determine that an arc exists in the direct current when a counting result of the quantity of arc events meets a preset condition.

Abstract: A method of allowing a user, using a wellness tracking device, to receive information associated with a wellness goal is described. The method comprises presenting at least one other user for the user to follow; allowing the user to select a user of the at least one other user to compare wellness information; and providing, to the user, the information related to wellness activities of the selected user.

Abstract: This application provides a noise generation circuit, a self-checking circuit, an AFCI, and a photovoltaic power generation system. The noise generation circuit includes a power switch module, a noise generator, and a capacitor, where the noise generator is connected to both the power switch module and the capacitor; the power switch module is configured to control, according to a self-checking instruction, whether the noise generator generates a noise signal; and the capacitor is configured to filter out a direct current component in the noise signal when the noise generator generates the noise signal. According to the noise generation circuit, the self-checking circuit, the AFCI, and the photovoltaic power generation system that are provided in this application, no noise signal is generated in a non self-checking time, thereby ensuring normal working of the AFCI and the photovoltaic inverter.

Abstract: This application provides a noise generation circuit, a self-checking circuit, an AFCI, and a photovoltaic power generation system. The noise generation circuit includes a power switch module, a noise generator, and a capacitor, where the noise generator is connected to both the power switch module and the capacitor; the power switch module is configured to control, according to a self-checking instruction, whether the noise generator generates a noise signal; and the capacitor is configured to filter out a direct current component in the noise signal when the noise generator generates the noise signal. According to the noise generation circuit, the self-checking circuit, the AFCI, and the photovoltaic power generation system that are provided in this application, no noise signal is generated in a non self-checking time, thereby ensuring normal working of the AFCI and the photovoltaic inverter.

Abstract: A circuit for arc detection in a direct current and a microprocessor to resolve a problem of low accuracy of a detection result of an existing circuit for arc detection in a direct current, where the circuit includes a current sampling circuit, a first circuit, a second circuit, and a microprocessor. The current sampling circuit is configured to perform current sampling on the direct current, and output a current sampling signal of the direct current. The first circuit is configured to output a time domain signal including at least one pulse. The second circuit is configured to output a frequency domain signal of the current sampling signal after amplifying and filtering the current sampling signal. The microprocessor is configured to determine that an arc exists in the direct current when a counting result of the quantity of arc events meets a preset condition.

Abstract: A method of allowing a user, using a wellness tracking device, to receive information associated with a wellness goal is described. The method comprises presenting at least one other user for the user to follow; allowing the user to select a user of the at least one other user to compare wellness information; and providing, to the user, the information related to wellness activities of the selected user.

Abstract: Provided is a petroleum fracturing proppant prepared from flyash and waste ceramics, the petroleum fracturing proppant being prepared from the following components: 40 wt. %-90 wt. % of main material, the main material being flyash and waste ceramics; 1 wt. %-40 wt. % of auxiliary material, the auxiliary material being potassium feldspar powder and manganese ore powder; and the sum of the main material and the auxiliary material is 100%. The present invention employs low-cost flyash and waste ceramics as raw material, and the petroleum fracturing proppant prepared under a low temperature has low apparent density and strong crushing resistance, and is also low cost and reduces energy consumption.

Abstract: Provided is a petroleum fracturing proppant prepared from flyash and waste ceramics, the petroleum fracturing proppant being prepared from the following components: 40 wt. %-90 wt. % of main material, the main material being flyash and waste ceramics; 1 wt. %-40 wt. % of auxiliary material, the auxiliary material being potassium feldspar powder and manganese ore powder; and the sum of the main material and the auxiliary material is 100%. The present invention employs low-cost flyash and waste ceramics as raw material, and the petroleum fracturing proppant prepared under a low temperature has low apparent density and strong crushing resistance, and is also low cost and reduces energy consumption.