The subcarrier allocation problem in cognitive radio（CR）networks with multi-user orthogonal frequency-division multiplexing（OFDM）and distributed antenna is analyzed and modeled for the flat fading channel and the ...The subcarrier allocation problem in cognitive radio（CR）networks with multi-user orthogonal frequency-division multiplexing（OFDM）and distributed antenna is analyzed and modeled for the flat fading channel and the frequency selective channel,where the constraint on the secondary user（SU）to protect the primary user（PU）is that the total throughput of each PU must be above the given threshold instead of the ＂interference temperature＂.According to the features of different types of channels,the optimal subcarrier allocation schemes are proposed to pursue efficiency（or maximal throughput）,using the branch and bound algorithm and the 0-1 implicit enumeration algorithm.Furthermore,considering the tradeoff between efficiency and fairness,the optimal subcarrier allocation schemes with fairness are proposed in different fading channels,using the pegging algorithm.Extensive simulation results illustrate the significant performance improvement of the proposed subcarrier allocation schemes compared with the existing ones in different scenarios.展开更多
Based on the detailed petrographic study,the characteristics of source region of the Weiya gabbro and tectonic implications were studied.The results show that the gabbroic rock consists mainly of gabbro,with less amou...Based on the detailed petrographic study,the characteristics of source region of the Weiya gabbro and tectonic implications were studied.The results show that the gabbroic rock consists mainly of gabbro,with less amount of ultra-mafic rocks.The ultra-mafic rocks show cumulate texture and are gradually transitional contact with gabbro,indicating that they are cumulate products of parental magma.The ultra-mafic rocks consist mainly of spinel periodite and spinel clinopyroxenite.The former is mainly composed of olivine(65%-70%),spinel(10%-15%),hornblende(5%-10%) and phlogopite(5%-10%);the latter consists mainly of clinopyroxene(70%-80%),spinel(15%-20%) and phlogopite(0-10%),with minor amounts of carbonate(0-2%).No olivine or orthopyroxene is found.The gabbro is composed mainly of clinopyroxene(35%-40%),plagioclase(An 55-65,40%-45%),hornblende(5%-15%),with variable amounts of carbonate(0-5%).Petrographic observations show that the source region of the Weiya gabbroic rock is water-rich due to intensive intra-continental A-type subduction occurring in this region during late Permian to early Triassic.展开更多
Objective： To explore effective modelity for slow transit constipation （STC） and provide evidence for standardization of pattern identification of STC. Methods： Sixty eight cases of STC patients were randomly and ...Objective： To explore effective modelity for slow transit constipation （STC） and provide evidence for standardization of pattern identification of STC. Methods： Sixty eight cases of STC patients were randomly and evenly assigned into acupuncture group （n=34） and medication （control） group （n=34）. In acupuncture group, Tianshu （天枢 ST 25） and Zhigou （支沟 TE 6） were punctured and stimulated electrically by setting the parameters of 1 Hz, continuous waves, suitable strength and duration of 30 min. Patients of the control group were ordered to take Tongbionling （bowel-movernent promotion） Capsule, 5 cap sules/time, once daily. Results： After 28 days＇ treatment, symptom scores in both groups were decreased significantly and colonic ejection rates within 72 hours increased considerably in comparison with pre-treatment （ P〈 0, 01 ） ; and the therapeutic effects of acupuncture group were remarkably better than those of control group in lowering symptom score and raising colonic ejection rate （P〈0.01）. Conclusion： Acupuncture is a simple and practical method for the treatment of STC and its therapeutic effect is reliable.展开更多
In this study, meteorological factors and snowmelt rate at an open site on sunny slope(OPS) and beneath forest canopy openness on shady slope(BFC) were measured using an automatic weather station and snow lysimeter du...In this study, meteorological factors and snowmelt rate at an open site on sunny slope(OPS) and beneath forest canopy openness on shady slope(BFC) were measured using an automatic weather station and snow lysimeter during the snowmelt period in 2009, 2010 and 2013. The energy budget over snow surface was calculated according to these meteorological datasets. The analysis results indicated that the net shortwave radiation(K) and sensible heat flux(H) were energy sources, and the latent heat flux(LVE) was energy sinks of snow surfaces at all sites. The net longwave radiation(L) was energy sink at OPS and 80% BFC, but energy source at 20% BFC. The gain of K, H, and the loss of LVE at BFC were obviously lower than those at OPS. The L was the maximum difference of energy budget between snow surface at BFC and OPS. In warm and wet years, the most important factor of the energy budget variation at OPS was air humidity and the second mostimportant factor was air temperature. However, the ground surface temperature on the sunny slope was the most important factor for L and energy budget at BFC. With the increases in forest canopy openness and the slope of adjacent terrains, the influences of ground surface temperature on the sunny slope on L and the energy budget over snow surface at BFC increased, especially when the snow cover on the sunny slope melts completely.展开更多
基金The National Natural Science Foundation of China(No.60832009)Beijing Municipal Natural Science Foundation(No.4102044)National Major Science & Technology Project(No.2009ZX03003-003-01)
文摘The subcarrier allocation problem in cognitive radio（CR）networks with multi-user orthogonal frequency-division multiplexing（OFDM）and distributed antenna is analyzed and modeled for the flat fading channel and the frequency selective channel,where the constraint on the secondary user（SU）to protect the primary user（PU）is that the total throughput of each PU must be above the given threshold instead of the ＂interference temperature＂.According to the features of different types of channels,the optimal subcarrier allocation schemes are proposed to pursue efficiency（or maximal throughput）,using the branch and bound algorithm and the 0-1 implicit enumeration algorithm.Furthermore,considering the tradeoff between efficiency and fairness,the optimal subcarrier allocation schemes with fairness are proposed in different fading channels,using the pegging algorithm.Extensive simulation results illustrate the significant performance improvement of the proposed subcarrier allocation schemes compared with the existing ones in different scenarios.
基金Projects(40672040,40472042 and 40603008) supported by the National Natural Science Foundation of ChinaProject(2001CB409802) supported by the Major State Basic Research Development Program of China+1 种基金 Project(2005038237) supported by the Postdoctoral Science Foundation of China Project supported by the Opening Foundation of State Key Laboratory of Continental Dynamics,Northwest University
文摘Based on the detailed petrographic study,the characteristics of source region of the Weiya gabbro and tectonic implications were studied.The results show that the gabbroic rock consists mainly of gabbro,with less amount of ultra-mafic rocks.The ultra-mafic rocks show cumulate texture and are gradually transitional contact with gabbro,indicating that they are cumulate products of parental magma.The ultra-mafic rocks consist mainly of spinel periodite and spinel clinopyroxenite.The former is mainly composed of olivine(65%-70%),spinel(10%-15%),hornblende(5%-10%) and phlogopite(5%-10%);the latter consists mainly of clinopyroxene(70%-80%),spinel(15%-20%) and phlogopite(0-10%),with minor amounts of carbonate(0-2%).No olivine or orthopyroxene is found.The gabbro is composed mainly of clinopyroxene(35%-40%),plagioclase(An 55-65,40%-45%),hornblende(5%-15%),with variable amounts of carbonate(0-5%).Petrographic observations show that the source region of the Weiya gabbroic rock is water-rich due to intensive intra-continental A-type subduction occurring in this region during late Permian to early Triassic.
文摘Objective： To explore effective modelity for slow transit constipation （STC） and provide evidence for standardization of pattern identification of STC. Methods： Sixty eight cases of STC patients were randomly and evenly assigned into acupuncture group （n=34） and medication （control） group （n=34）. In acupuncture group, Tianshu （天枢 ST 25） and Zhigou （支沟 TE 6） were punctured and stimulated electrically by setting the parameters of 1 Hz, continuous waves, suitable strength and duration of 30 min. Patients of the control group were ordered to take Tongbionling （bowel-movernent promotion） Capsule, 5 cap sules/time, once daily. Results： After 28 days＇ treatment, symptom scores in both groups were decreased significantly and colonic ejection rates within 72 hours increased considerably in comparison with pre-treatment （ P〈 0, 01 ） ; and the therapeutic effects of acupuncture group were remarkably better than those of control group in lowering symptom score and raising colonic ejection rate （P〈0.01）. Conclusion： Acupuncture is a simple and practical method for the treatment of STC and its therapeutic effect is reliable.
基金funded by the National Natural Science Foundation of China (41271098, 41171066)the National Key Technology Research and Development Program of the Ministry of Science and Technology of China (2012BAC23B01)
文摘In this study, meteorological factors and snowmelt rate at an open site on sunny slope(OPS) and beneath forest canopy openness on shady slope(BFC) were measured using an automatic weather station and snow lysimeter during the snowmelt period in 2009, 2010 and 2013. The energy budget over snow surface was calculated according to these meteorological datasets. The analysis results indicated that the net shortwave radiation(K) and sensible heat flux(H) were energy sources, and the latent heat flux(LVE) was energy sinks of snow surfaces at all sites. The net longwave radiation(L) was energy sink at OPS and 80% BFC, but energy source at 20% BFC. The gain of K, H, and the loss of LVE at BFC were obviously lower than those at OPS. The L was the maximum difference of energy budget between snow surface at BFC and OPS. In warm and wet years, the most important factor of the energy budget variation at OPS was air humidity and the second mostimportant factor was air temperature. However, the ground surface temperature on the sunny slope was the most important factor for L and energy budget at BFC. With the increases in forest canopy openness and the slope of adjacent terrains, the influences of ground surface temperature on the sunny slope on L and the energy budget over snow surface at BFC increased, especially when the snow cover on the sunny slope melts completely.
