Confronted with the sudden devastating quakes that rocked Sichuan and half China on May 12, the Chinese government and the Chinese people transformed the sorrow and grievances into enormous force and stood up from...Confronted with the sudden devastating quakes that rocked Sichuan and half China on May 12, the Chinese government and the Chinese people transformed the sorrow and grievances into enormous force and stood up from the debris undaunted.展开更多
An investigation is presented on the performance of a small-scale solar power and heating system with short parabolic trough collectors(PTCs). The steady-state model of the short PTCs is evaluated with outside experim...An investigation is presented on the performance of a small-scale solar power and heating system with short parabolic trough collectors(PTCs). The steady-state model of the short PTCs is evaluated with outside experiments. The model mainly contains the heat loss of the receiver, the peak optical efficiency and the incident angle factor consisting of incident angle modifier and end loss. It is found that the end loss effect is essential in this model when the length of the PTCs is less than 48 m, especially in the winter. The standard deviation of the steady-state model is 1.4%. Moreover, the potential energy efficiency ratio of the solar power and heating system is considerably larger than the coefficient of performance(COP) of general air-source heat pumps, and increases with the decrease of the condensation temperature. An overall system efficiency of 49% can be reached. Lastly,the existence of a water storage tank improves the flexibility of heating the building, and the volume of the water storage tank decreases with the increase of the heating water temperature.展开更多
Although carbon fiber electromagnetic wave absorbing materials have shown great potential in the field of electromagnetic protection,the currently reported carbon fiber-based absorbers are limited to the manipulation ...Although carbon fiber electromagnetic wave absorbing materials have shown great potential in the field of electromagnetic protection,the currently reported carbon fiber-based absorbers are limited to the manipulation of composition and external structure,lacking the design of intrinsic morphology.To fill the above-mentioned gap,this work presents a spiral carbon fiber compounded with CoNi magnetic nanoparticles(CoNi@SCF).Attributed to its special morphology and dielectric-magnetic synergy,this material offers abundant attenuation mechanisms,demonstrating strong absorption at multiple frequencies with broadband application potential.In particular,the maximum reflection loss and effective absorption bandwidth of CoNi@SCF reach-66.5 dB at 2.9 mm and 6.6 GHz at 2.1 mm,respectively,and the maximum RCS reduction value of 41.5 dB m^(2) also confirms the actual efficiency.In addition,gelation and hydrophobic modification experiments have been explored to meet the requirements for the employment of magnetic carbon fibers in practical scenarios.Therefore,this work may provide new inspiration for the design and manufacture of novel magnetic carbon fiber absorbers with great stability and multiband absorption performance.展开更多
The practice of more than 30 years of building socialism with Chinese characteristics contains within it a five-step evolution： ＂functional thinking → government leadership theoretical guidance → hybrid structure...The practice of more than 30 years of building socialism with Chinese characteristics contains within it a five-step evolution： ＂functional thinking → government leadership theoretical guidance → hybrid structure → the people in the principal position＂; in the course of the further development of the practice of building socialism with Chinese characteristics, the important responsibility and mission of Chinese Communists （exercising governance for the people） and the new expectations of the people （innovative practice） determine that its basic tendency should be to carry out reform and breakthroughs at three levels： ＂deep structures → core institutions → operational means,＂ embodied in ＂structural adjustment → restructuring → change of methods →construction of order.＂展开更多
文摘Confronted with the sudden devastating quakes that rocked Sichuan and half China on May 12, the Chinese government and the Chinese people transformed the sorrow and grievances into enormous force and stood up from the debris undaunted.
基金the Special Research Fund for the National Key Research and Development Program of China(No.2016YFB0901300)
文摘An investigation is presented on the performance of a small-scale solar power and heating system with short parabolic trough collectors(PTCs). The steady-state model of the short PTCs is evaluated with outside experiments. The model mainly contains the heat loss of the receiver, the peak optical efficiency and the incident angle factor consisting of incident angle modifier and end loss. It is found that the end loss effect is essential in this model when the length of the PTCs is less than 48 m, especially in the winter. The standard deviation of the steady-state model is 1.4%. Moreover, the potential energy efficiency ratio of the solar power and heating system is considerably larger than the coefficient of performance(COP) of general air-source heat pumps, and increases with the decrease of the condensation temperature. An overall system efficiency of 49% can be reached. Lastly,the existence of a water storage tank improves the flexibility of heating the building, and the volume of the water storage tank decreases with the increase of the heating water temperature.
基金financially supported by the Natural Science Foundation of Shandong Province(No.ZR2023YQ009)the State Key Laboratory of Heavy Oil Processing(No.SKLHOP202403003)
文摘Although carbon fiber electromagnetic wave absorbing materials have shown great potential in the field of electromagnetic protection,the currently reported carbon fiber-based absorbers are limited to the manipulation of composition and external structure,lacking the design of intrinsic morphology.To fill the above-mentioned gap,this work presents a spiral carbon fiber compounded with CoNi magnetic nanoparticles(CoNi@SCF).Attributed to its special morphology and dielectric-magnetic synergy,this material offers abundant attenuation mechanisms,demonstrating strong absorption at multiple frequencies with broadband application potential.In particular,the maximum reflection loss and effective absorption bandwidth of CoNi@SCF reach-66.5 dB at 2.9 mm and 6.6 GHz at 2.1 mm,respectively,and the maximum RCS reduction value of 41.5 dB m^(2) also confirms the actual efficiency.In addition,gelation and hydrophobic modification experiments have been explored to meet the requirements for the employment of magnetic carbon fibers in practical scenarios.Therefore,this work may provide new inspiration for the design and manufacture of novel magnetic carbon fiber absorbers with great stability and multiband absorption performance.
文摘The practice of more than 30 years of building socialism with Chinese characteristics contains within it a five-step evolution： ＂functional thinking → government leadership theoretical guidance → hybrid structure → the people in the principal position＂; in the course of the further development of the practice of building socialism with Chinese characteristics, the important responsibility and mission of Chinese Communists （exercising governance for the people） and the new expectations of the people （innovative practice） determine that its basic tendency should be to carry out reform and breakthroughs at three levels： ＂deep structures → core institutions → operational means,＂ embodied in ＂structural adjustment → restructuring → change of methods →construction of order.＂
