We investigate sympathetic cooling fermions 40K by evaporatively cooling bosonic 87Rb atoms in a magnetic trap with microwave and radio frequency induced evaporations in detail. The mixture of bosonic and fermionic at...We investigate sympathetic cooling fermions 40K by evaporatively cooling bosonic 87Rb atoms in a magnetic trap with microwave and radio frequency induced evaporations in detail. The mixture of bosonic and fermionic atoms is prepared in their polarized spin states IF = 9/2, mF = 9/2） for 40K and IF = 2, mF=2〉 for 87Rb, which is trapped in Quadrupole-Ioffe-Configuration trap. Comparing microwave with radio frequency evaporatively cooling bosonic STRb atoms with sympathetically cooling Fermi gas 40K, we find that the presence of rubidium atoms in the [2, 1} Zeeman states, which are generated in the evaporative process, gives rise to a significant loss of 40K due to inelastic collisions. Thus, the rubidium atoms populated in the [2, 1} Zeeman states should be removed in order to effectively perform sympathetically cooling 40K with the evaporatively cooled STRb atoms.展开更多
Biomass conversion by plasma has the advantage of mainly producing gaseous products, H2, CO and CO2. Though the thermal plasma has been used for this conversion, the plasma temperature is too high to be unfit for the ...Biomass conversion by plasma has the advantage of mainly producing gaseous products, H2, CO and CO2. Though the thermal plasma has been used for this conversion, the plasma temperature is too high to be unfit for the conversion biomass. The temperature of cold plasma, however, is lower under 3000 K. It expects to be adequate for biomass conversion. Cold plasma can be obtained with irradiation microwave (2.45 GHz) or radio frequency (13.5 MHz) under reduce gas pressure. Therefore, in present study, the effective decomposition of cellulose by microwave plasma (MWP) and radio frequency plasma (RFP) is examined. The conversion of cellulose by MWP (XMWP) is higher than that by RFP (XRFP), irrespective of the reaction time. XMWP and XRFP reach 92.8 wt% at 10 min and 68.1 wt% at 30 min. The maximum yield of gaseous products (Ygas) by MWP is 85.1 wt% at 10 min, higher by 23.2 wt% than Ygas by RFP at 30 min. The amount of H2 and CO obtained by MWP is 18.0 mmol/g and 23.5 mmol/g, it is larger than that obtained by RFP. Comparing the relationship between conversion and yield, Ygas of MWP is slightly higher than that of RFP under X of 60 wt%, and both Ygas is almost same over 60 wt%. The amount of H2 and CO obtained by MWP is larger by 9.3 mmol/g and 9.6 mmol/g than that obtained by RFP. C, H and O element in cellulose is mainly distributed to H2 and CO by MWP. RFP mainly distributes H and O element to the other gases without H2 and CO. In addition, a large amount of C element is remains in the residue. Those results is found that MWP was more suitable for cellulose gasification than RFP, since MWP can highly convert C, H and O element to H2 and CO by higher energy of microwave frequency in comparison with radio frequency.展开更多
Two groups of microwave type U and Reverse-Slope(RS)bursts after the Soft X-Ray(SXR)maximum were observed with the 2.6~3.8GHz spectrometer of Chinese Solar Broadband Radio Spectrometers(SBRS/Huairou)on 15 February 201...Two groups of microwave type U and Reverse-Slope(RS)bursts after the Soft X-Ray(SXR)maximum were observed with the 2.6~3.8GHz spectrometer of Chinese Solar Broadband Radio Spectrometers(SBRS/Huairou)on 15 February 2011,when an X2.2 solar flare occurred in the Active Region(AR)NOAA 11158.A Shear-driven Quadrupolar Reconnection(SQR)model was utilized to analyze these bursts and the two loops involved were found to be basically in the same spatial scale and have a height difference of about 1300 km.These bursts were interpreted to be a result of a new reconnection process between the two similar-scaled loops.展开更多
The microwave back-scattering characteristics are numerically analysed by the elec-tromagnetic scattering theory,and the sea wave height spectrum that reflects the wind field isrebuilt by comparing the calculated data...The microwave back-scattering characteristics are numerically analysed by the elec-tromagnetic scattering theory,and the sea wave height spectrum that reflects the wind field isrebuilt by comparing the calculated data with experimental data which were measured by airbornescatter.According to the wave height spectrum,the relationship between the back-scattering co-efficients and wind speeds can be obtained.Once the back-scattering coefficients of the sea surfaceare measured,then the wind speeds over the sea surface can approximately be determined.It isuseful for the microwave remote sensing in ocean.展开更多
Microwave photonics is a combination of microwave and photonics in concepts,devices and systems.Its typical research involves optical generation,processing and conversion of microwave signals,as well as distribution a...Microwave photonics is a combination of microwave and photonics in concepts,devices and systems.Its typical research involves optical generation,processing and conversion of microwave signals,as well as distribution and transmission of microwave signals on optical links.Research achievements of microwave photonics have promoted the development of some new technologies,including Radio over Fiber (RoF) communication,subcarrier multiplexing and fiber transmission in Cable Television (CATV) system,optical controlled beam forming network with phased array radar and measurement technologies in microwave frequency domain.展开更多
With the shortage of energy and the rise of crude oil in the world, the development of oil shale is gaining more attention globally. To solve the problem of traditional heat conduction with low efficiency and high cos...With the shortage of energy and the rise of crude oil in the world, the development of oil shale is gaining more attention globally. To solve the problem of traditional heat conduction with low efficiency and high cost for oil shale, a new technology called radio frequency (RF) heating (microwave heating) is introduced in this paper. Radio frequency electromagnetic (microwave) can do work directly on medium molecule of oil shale and change into heat energy, the transmission of which allows both inner and outer molecules heating simultaneously without heat conduction. Meanwhile, oil shale is a poor microwave absorbing material and microwave absorbents must be added to reach pyrolysis temperature. By this means, shale oil could be heated at a higher speed and kerogen will gradually be cracked into gas and oil. Then shale oil and gas will flow into the production wells through fractures generated by heating and be pumped up to the surface.展开更多
Ⅰ.INTRODUVTION This paper made preliminaily reduction of the data which we observed in March1989 at the active region AR5395. I list a part of microwave bursts and draw out a few oftime profiles at the end of the paper.
利用2021年2—5月和8—11月青藏高原东坡高海拔宇宙线观测站(Large High Altitude Air Shower Observatory,LHAASO)多通道微波辐射计观测的高时空分辨率温度廓线数据,并结合2021年ERA5再分析资料,分析大气边界层高度(Atmospheric Bounda...利用2021年2—5月和8—11月青藏高原东坡高海拔宇宙线观测站(Large High Altitude Air Shower Observatory,LHAASO)多通道微波辐射计观测的高时空分辨率温度廓线数据,并结合2021年ERA5再分析资料,分析大气边界层高度(Atmospheric Boundary Layer Height,ABLH)的日、月和季平均日变化规律。结果表明:(1)晴朗天气的ABLH具有明显的波峰波谷变化,日出后地表温度升高,ABLH也随之持续升高,最大值通常出现在午后,至18时左右迅速降低,日落之后降至最低。(2)一年之中,4月平均ABLH最大,约为1200 m,11月只有600 m。ABLH白天波动大,夜晚稳定,平均降至400 m左右。基于ERA5再分析资料反演的ABLH整体结果偏小,但具有与微波辐射计一致的变化趋势。(3)ABLH最大值出现在春季,夏季和秋季次之,冬季最小,且均在14:00—15:00达到峰值。展开更多
基金Project supported by the National Science Foundation for Distinguished Young Scholars of China(Grant No.10725416)the National Basic Research Program of China(Grant No.2006CB921101 and 2011CB921601)the National Science Foundation NSFC Project for Excellent Research Team,China(Grant No.60821004)
文摘We investigate sympathetic cooling fermions 40K by evaporatively cooling bosonic 87Rb atoms in a magnetic trap with microwave and radio frequency induced evaporations in detail. The mixture of bosonic and fermionic atoms is prepared in their polarized spin states IF = 9/2, mF = 9/2） for 40K and IF = 2, mF=2〉 for 87Rb, which is trapped in Quadrupole-Ioffe-Configuration trap. Comparing microwave with radio frequency evaporatively cooling bosonic STRb atoms with sympathetically cooling Fermi gas 40K, we find that the presence of rubidium atoms in the [2, 1} Zeeman states, which are generated in the evaporative process, gives rise to a significant loss of 40K due to inelastic collisions. Thus, the rubidium atoms populated in the [2, 1} Zeeman states should be removed in order to effectively perform sympathetically cooling 40K with the evaporatively cooled STRb atoms.
文摘Biomass conversion by plasma has the advantage of mainly producing gaseous products, H2, CO and CO2. Though the thermal plasma has been used for this conversion, the plasma temperature is too high to be unfit for the conversion biomass. The temperature of cold plasma, however, is lower under 3000 K. It expects to be adequate for biomass conversion. Cold plasma can be obtained with irradiation microwave (2.45 GHz) or radio frequency (13.5 MHz) under reduce gas pressure. Therefore, in present study, the effective decomposition of cellulose by microwave plasma (MWP) and radio frequency plasma (RFP) is examined. The conversion of cellulose by MWP (XMWP) is higher than that by RFP (XRFP), irrespective of the reaction time. XMWP and XRFP reach 92.8 wt% at 10 min and 68.1 wt% at 30 min. The maximum yield of gaseous products (Ygas) by MWP is 85.1 wt% at 10 min, higher by 23.2 wt% than Ygas by RFP at 30 min. The amount of H2 and CO obtained by MWP is 18.0 mmol/g and 23.5 mmol/g, it is larger than that obtained by RFP. Comparing the relationship between conversion and yield, Ygas of MWP is slightly higher than that of RFP under X of 60 wt%, and both Ygas is almost same over 60 wt%. The amount of H2 and CO obtained by MWP is larger by 9.3 mmol/g and 9.6 mmol/g than that obtained by RFP. C, H and O element in cellulose is mainly distributed to H2 and CO by MWP. RFP mainly distributes H and O element to the other gases without H2 and CO. In addition, a large amount of C element is remains in the residue. Those results is found that MWP was more suitable for cellulose gasification than RFP, since MWP can highly convert C, H and O element to H2 and CO by higher energy of microwave frequency in comparison with radio frequency.
基金Supported by National Basic Research Program of Ministry of Science and Technology of China(2011CB811401)the National Major Scientific Equipment Research and Development Project(ZDYZ2009-3)National Natural Science Foundation of China(11211120147,11221063,11273030,11103044,11103039,11373039)
文摘Two groups of microwave type U and Reverse-Slope(RS)bursts after the Soft X-Ray(SXR)maximum were observed with the 2.6~3.8GHz spectrometer of Chinese Solar Broadband Radio Spectrometers(SBRS/Huairou)on 15 February 2011,when an X2.2 solar flare occurred in the Active Region(AR)NOAA 11158.A Shear-driven Quadrupolar Reconnection(SQR)model was utilized to analyze these bursts and the two loops involved were found to be basically in the same spatial scale and have a height difference of about 1300 km.These bursts were interpreted to be a result of a new reconnection process between the two similar-scaled loops.
文摘The microwave back-scattering characteristics are numerically analysed by the elec-tromagnetic scattering theory,and the sea wave height spectrum that reflects the wind field isrebuilt by comparing the calculated data with experimental data which were measured by airbornescatter.According to the wave height spectrum,the relationship between the back-scattering co-efficients and wind speeds can be obtained.Once the back-scattering coefficients of the sea surfaceare measured,then the wind speeds over the sea surface can approximately be determined.It isuseful for the microwave remote sensing in ocean.
基金supported by the National Natural Science Foundation of China under Grant No.60736002 and No.60807026
文摘Microwave photonics is a combination of microwave and photonics in concepts,devices and systems.Its typical research involves optical generation,processing and conversion of microwave signals,as well as distribution and transmission of microwave signals on optical links.Research achievements of microwave photonics have promoted the development of some new technologies,including Radio over Fiber (RoF) communication,subcarrier multiplexing and fiber transmission in Cable Television (CATV) system,optical controlled beam forming network with phased array radar and measurement technologies in microwave frequency domain.
文摘With the shortage of energy and the rise of crude oil in the world, the development of oil shale is gaining more attention globally. To solve the problem of traditional heat conduction with low efficiency and high cost for oil shale, a new technology called radio frequency (RF) heating (microwave heating) is introduced in this paper. Radio frequency electromagnetic (microwave) can do work directly on medium molecule of oil shale and change into heat energy, the transmission of which allows both inner and outer molecules heating simultaneously without heat conduction. Meanwhile, oil shale is a poor microwave absorbing material and microwave absorbents must be added to reach pyrolysis temperature. By this means, shale oil could be heated at a higher speed and kerogen will gradually be cracked into gas and oil. Then shale oil and gas will flow into the production wells through fractures generated by heating and be pumped up to the surface.
文摘Ⅰ.INTRODUVTION This paper made preliminaily reduction of the data which we observed in March1989 at the active region AR5395. I list a part of microwave bursts and draw out a few oftime profiles at the end of the paper.
