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Measurements of heat collection rate and heat loss coefficient are crucial for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, conventional measurement requires expensive detection devices and undergoes a series of complicated procedures. To simplify the measurement and reduce the cost, software based on artificial neural networks for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters was developed. Using multilayer feed-forward neural networks with back-propagation algorithm, we developed and tested our program on the basis of 915measuredsamples of water-in-glass evacuated tube solar water heaters. This artificial neural networks-based software program automatically obtained accurate heat collection rateand heat loss coefficient using simply "portable test instruments" acquired parameters, including tube length, number of tubes, tube center distance, heat water mass in tank, collector area, angle between tubes and ground and final temperature. Our results show that this software (on both personal computer and Android platforms) is efficient and convenient to predict the heat collection rate and heat loss coefficient due to it slow root mean square errors in prediction. The software now can be downloaded from http://t.cn/RLPKF08.

Following the severe acute respiratory syndrome (SARS) and influenza H1N1 viral infections, the outbreak of corona virus disease 2019 (COVID-19) in China has once again drawn worldwide attention to infectious diseases. The process of biological particles such as viruses, bacteria, and fungi releasing and spreading into the air is one of the main transmission methods of infection (He et al., 2017). Therefore, a clean air environment is essential to prevent infection, particularly in the operating room (OR) where a patient's wounds are exposed; if airborne bacteria enter the wound, surgical site infections (SSIs) can result. SSIs are the second most common cause of healthcare-associated infections (HAIs) in Europe and the United States (Allegranzi et al., 2016

An asymmetric synthesis of HCV NS5B nucleoside polymerase inhibitor (1) is described. This novel route features several remarkably diastereoselective and high-yielding transformations, including construction of the all-carbon quaternary stereogenic center at C-2 via a thermodynamic aldol reaction. A subsequent glycosylation reaction with activated uracil via C-1 phosphate and installation of the cyclic phosphate group using an achiral phosphorus(III) reagent followed by oxidation provides 1.

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With the ever-increasing demand for resources, the task of geological surveys has increased rapidly, and automated geological drilling rigs that can improve the efficiency of geological surveys have become the mainstream research direction. Automated geological drilling rigs can improve construction efficiency, reduce labor intensity, and effectively reduce construction accidents. During the construction of geological survey operations, accidents such as drill breakage, stuck drill, and equipment damage, which are easily caused by drill pipe impact, occur from time to time. Therefore, drill pipe impact dynamics is currently a hot topic in academic research, but there are few studies that combine automated geological drilling rigs with drill pipe impact. This article starts with the research on the hydraulic system of the power head of the automatic drilling rig and studies the dynamics of the damage of the power head of the drilling rig caused by the impact of the drill pipe by means of hydraulic valve torque limit and closed-loop control of the speed. The oil valve group reduces the reverse torsional impact of the drill pipe on the hydraulic motor. At the same time, the requirements for the selection and pressure setting of the relief valve in the buffer filling oil valve group are proposed. The natural frequency of the relief valve is not less than 20 Hz, and the pressure is set to the working pressure 1.25 times. The effects of shock with or without the buffer filling oil valve group and the oil supply line on the power head motor were compared. The research results of this paper can provide theoretical reference and design basis for subsequent development of automated drilling rigs.