Si 0.8 Ge 0.2 strained epilayer were grown on Si substrates by rapid thermal process/very low pressure-chemical vapor deposition (RTP/VLP-CVD) and implanted with boron at 40 keV,a dosage of 2.5×10 14 ...Si 0.8 Ge 0.2 strained epilayer were grown on Si substrates by rapid thermal process/very low pressure-chemical vapor deposition (RTP/VLP-CVD) and implanted with boron at 40 keV,a dosage of 2.5×10 14 cm -2 .Rapid thermal annealing (RTA) and steady-state furnace annealing with different temperature and time period were performed for comparison.Results indicate that RTA is better than furnace annealing.After RTA at 750 ℃～850 ℃ for 10 s or at 700 ℃ for 40 s,the implantation induced damage can be removed,the carrier mobility was about 300 cm 2/V·s and the activity was nearly 100%.展开更多
Water mist technology provides efficient firefighting performance while there is still room for improvement. So varieties of additives have been studied in recent years both at home and abroad. The self-made additives...Water mist technology provides efficient firefighting performance while there is still room for improvement. So varieties of additives have been studied in recent years both at home and abroad. The self-made additives are used to compare the firefighting performance of diesel and heptane fire in open space. By adjusting the concentration of substance in the additives and conducting the experiment under the pressure of 0.3 MPa,0.5 MPa and 0.7 MPa,extinguish time and temperature are measured in the experiment. Through the experiments using different fuels,it can be found when the fuel is heptane that has a lower ignition point and a higher evaporation rate, the water mist additive can still significantly improve the firefighting performance. According to the data based on different concentrations of fluorinated surfactants,we find that fluorinated surfactants are the main substance to improve the performances by changing physical property of water mist. Optimal proportion of the additives for firefighting performance is found by experiment results.展开更多
To better understand potential pollutant formations during combustion of conventional hydrocarbon fuels blended with oxygenated fuels, detailed influences of ethanol as fuel additive on small polycyclic aromatic hydro...To better understand potential pollutant formations during combustion of conventional hydrocarbon fuels blended with oxygenated fuels, detailed influences of ethanol as fuel additive on small polycyclic aromatic hydrocarbons(PAHs) precursors, aldehydes, ketene and other important intermediate species in premixed fuel-rich low-pressure ethylene flames are distinguished among dilution, thermal and chemical effects of additives. Dominant effects of ethanol addition on each species are underlined respectively. Ethylene oxidation process is delayed when ethylene is substituted by ethanol. The influence of ethanol dilution and thermal effects on ethylene consumption are larger than chemical effects. CO mole fractions slightly decrease mainly as a result of dilution and thermal effects of added ethanol. The reductions in small PAHs precursors(acetylene and propargyl) are attributed to dilution and thermal effects of ethanol addition instead of chemical effects. The ethanol chemical effects promote formations of hazardous pollutants formaldehyde and acetaldehyde, and especially are responsible for the significant increase of acetaldehyde. C2H6, C4H2 and C4H4 mole fractions decrease in a similar way with acetylene and propargyl as ethanol is added. Ethanol used here only serves as a prototype of oxygenated additive, and identification method in this work is more universal which can be easily extended for analyzing other fuel blends of hydrocarbon and oxygenated fuels.展开更多
The effects of fire extinguishment with water mist by adding different additives were studied.Tens of chemical substances (including alkali metal salt,dilution agent and surface active agent) were selected as additive...The effects of fire extinguishment with water mist by adding different additives were studied.Tens of chemical substances (including alkali metal salt,dilution agent and surface active agent) were selected as additives due to their different extinct mechanisms.At first the performance of fire extinguishment with single additive was studied,then the effects of the same kinds of chemical substances under the same mass fraction were compared to study their influences on the fire extinguishment factors,including extinct time,fire temperature and oxygen concentration from which the fire extinct mechanism with additives could be concluded.Based on this the experiments were conducted to study the cooperate effect of the complexity of different additives.It indicated the relations between different firefighting mechanisms and different additives were competitive.From a large number of experiments the extinct mechanism with water mist by adding additives was concluded and an optimal compounding additive was selected.展开更多
文摘Si 0.8 Ge 0.2 strained epilayer were grown on Si substrates by rapid thermal process/very low pressure-chemical vapor deposition (RTP/VLP-CVD) and implanted with boron at 40 keV,a dosage of 2.5×10 14 cm -2 .Rapid thermal annealing (RTA) and steady-state furnace annealing with different temperature and time period were performed for comparison.Results indicate that RTA is better than furnace annealing.After RTA at 750 ℃～850 ℃ for 10 s or at 700 ℃ for 40 s,the implantation induced damage can be removed,the carrier mobility was about 300 cm 2/V·s and the activity was nearly 100%.
基金Opening Fund of State Key Laboratory of Fire Science,University of Science and Technology of China(No.HZ2011-KF04)
文摘Water mist technology provides efficient firefighting performance while there is still room for improvement. So varieties of additives have been studied in recent years both at home and abroad. The self-made additives are used to compare the firefighting performance of diesel and heptane fire in open space. By adjusting the concentration of substance in the additives and conducting the experiment under the pressure of 0.3 MPa,0.5 MPa and 0.7 MPa,extinguish time and temperature are measured in the experiment. Through the experiments using different fuels,it can be found when the fuel is heptane that has a lower ignition point and a higher evaporation rate, the water mist additive can still significantly improve the firefighting performance. According to the data based on different concentrations of fluorinated surfactants,we find that fluorinated surfactants are the main substance to improve the performances by changing physical property of water mist. Optimal proportion of the additives for firefighting performance is found by experiment results.
基金supported by the National Natural Science Foundation of China(Grant No.51306091)the Jiangsu Provincial Natural Science Foundation of China(Grant Nos.BK20140034,BK20130758)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.30920140111005)the Jiangsu Provincial Project of"Six Talent Summit"(Grant No.2014-XNY-002)
文摘To better understand potential pollutant formations during combustion of conventional hydrocarbon fuels blended with oxygenated fuels, detailed influences of ethanol as fuel additive on small polycyclic aromatic hydrocarbons(PAHs) precursors, aldehydes, ketene and other important intermediate species in premixed fuel-rich low-pressure ethylene flames are distinguished among dilution, thermal and chemical effects of additives. Dominant effects of ethanol addition on each species are underlined respectively. Ethylene oxidation process is delayed when ethylene is substituted by ethanol. The influence of ethanol dilution and thermal effects on ethylene consumption are larger than chemical effects. CO mole fractions slightly decrease mainly as a result of dilution and thermal effects of added ethanol. The reductions in small PAHs precursors(acetylene and propargyl) are attributed to dilution and thermal effects of ethanol addition instead of chemical effects. The ethanol chemical effects promote formations of hazardous pollutants formaldehyde and acetaldehyde, and especially are responsible for the significant increase of acetaldehyde. C2H6, C4H2 and C4H4 mole fractions decrease in a similar way with acetylene and propargyl as ethanol is added. Ethanol used here only serves as a prototype of oxygenated additive, and identification method in this work is more universal which can be easily extended for analyzing other fuel blends of hydrocarbon and oxygenated fuels.
基金supported by National Natural Science Foundation of China(No.51078014)supported by the Fundamental Research Funds for the Central Universities (YWF-10-01-B11)
文摘The effects of fire extinguishment with water mist by adding different additives were studied.Tens of chemical substances (including alkali metal salt,dilution agent and surface active agent) were selected as additives due to their different extinct mechanisms.At first the performance of fire extinguishment with single additive was studied,then the effects of the same kinds of chemical substances under the same mass fraction were compared to study their influences on the fire extinguishment factors,including extinct time,fire temperature and oxygen concentration from which the fire extinct mechanism with additives could be concluded.Based on this the experiments were conducted to study the cooperate effect of the complexity of different additives.It indicated the relations between different firefighting mechanisms and different additives were competitive.From a large number of experiments the extinct mechanism with water mist by adding additives was concluded and an optimal compounding additive was selected.
