The large accelerations of plasma were observed early in type-Ⅰ comet tail. The accelerations can reach 300 cm/S^2. Recently, the direct measurements for comet G-Z show that the energy of particles reaches 2×10~...The large accelerations of plasma were observed early in type-Ⅰ comet tail. The accelerations can reach 300 cm/S^2. Recently, the direct measurements for comet G-Z show that the energy of particles reaches 2×10~5 eV. It is much higher than the initial展开更多
The solar wind disturbances result in the emergence of condensation structures in plasma comet tails. Most of them are correlated with plasma vortex flows. The features of condensations are analysed. Based on the theo...The solar wind disturbances result in the emergence of condensation structures in plasma comet tails. Most of them are correlated with plasma vortex flows. The features of condensations are analysed. Based on the theories of magnetic hydrodynamics and forcefree fields, the construction and the distribution of magnetic field and its energy in condensations are specifically discussed. Details on the coupling process between an unsteady plasma motion and a magnetic field are given. The coupling effect makes the energy in comet tails change into a force-free field in condensation, so that the magnetic field energy in the condensation continuously increases. Many phenomena observed in comet tails can be explained with the idea.展开更多
A global analysis of the ro-vibrational spectra of 19 bands in the comet-tail （A2Πi-X2Σ＋） system of the 12C16O＋ cation is presented, and the precise molecular constants of the vibrational levels involved are obt...A global analysis of the ro-vibrational spectra of 19 bands in the comet-tail （A2Πi-X2Σ＋） system of the 12C16O＋ cation is presented, and the precise molecular constants of the vibrational levels involved are obtained via a weighted nonlinear least-squares fitting procedure. Furthermore, the resultant precise equilibrium molecular constants enable us to achieve accurate Rydberg-Klein-Rees （RKR） potential curves for both the A and X states, yielding the accurate Franck-Condon factor and band origin of each band in this system.展开更多
In this paper, we adopted a reasonable particle distribution function and used a simplified judgement to analyze the possibility of the ion-pickup caused by two-stream instibility in cometary tail. On calculation, we ...In this paper, we adopted a reasonable particle distribution function and used a simplified judgement to analyze the possibility of the ion-pickup caused by two-stream instibility in cometary tail. On calculation, we get an energy limitation(ΔE 1, ΔE 2) between the solar wind particles and the cometary particles .When the energy diffference is between ΔE 1 and ΔE 2, the pickup of ions in the cometary tail is more effective.展开更多
The velocity shear instability in a magnetized, three-component dusty plasma is investigated for both positively and negatively charged dust particles. The critical shears as a function of the relative charge of dust ...The velocity shear instability in a magnetized, three-component dusty plasma is investigated for both positively and negatively charged dust particles. The critical shears as a function of the relative charge of dust grains for both positively and negatively charged dust grains are in the same form. The instability excitation is easier in colder proton’s environment for positively charged dust, and so also in colder electron’s environment for negatively charged dust. For a certain flow pattern, the instability excites in different direction for different sign of charged dust grains. This conclusion may be helpful in interpreting the helical structures and streamer splitted phenomena in a cometary tail.展开更多
目的探讨经胸超声慧星尾征在心力衰竭患者心功能评价中的应用。方法选取因急性呼吸困难入院患者187例,分为急性左心衰竭（acute left heart failure,ALHF）组和非急性左心衰竭（non-acute left heart failure,NALHF）组。对比分析两组...目的探讨经胸超声慧星尾征在心力衰竭患者心功能评价中的应用。方法选取因急性呼吸困难入院患者187例,分为急性左心衰竭（acute left heart failure,ALHF）组和非急性左心衰竭（non-acute left heart failure,NALHF）组。对比分析两组患者肺部超声彗星尾征（ULCs）数目,超声心动图测量LAD、LVEDD、E/Ea值和EF值,并绘制ROC曲线,计算曲线下面积并寻找最佳诊断分界点。结果 ALHF组患者ULCs数目、左心房内径（LAD）、左室舒张末内径（LVEDD）、E/Ea值均显著高于NALHF组,而EF值显著低于NALHF组,其差异有统计学意义（P〈0.05）。ROC曲线下面积为0.946（95%CI 0.921~0.971）,当彗尾数〉5条时,诊断心源性呼吸困难的特异性为79.6%（95%CI 66.5%~92.8%）,敏感性为92.7%（95%CI79.2%~95.3%）,阳性预测值为90.67%（95%CI 68.29%~96.17%）,阴性预测值为79.3%（95%CI 65.1%~86.9%）,诊断准确率为82.9%（155/187）。结论经胸超声慧星尾征能够简单、准确地评估心功能状态,临床上可列入急性呼吸困难的常规筛查。展开更多
基金Project supported by the National Natural Science Foundation of China.
文摘The large accelerations of plasma were observed early in type-Ⅰ comet tail. The accelerations can reach 300 cm/S^2. Recently, the direct measurements for comet G-Z show that the energy of particles reaches 2×10~5 eV. It is much higher than the initial
文摘The solar wind disturbances result in the emergence of condensation structures in plasma comet tails. Most of them are correlated with plasma vortex flows. The features of condensations are analysed. Based on the theories of magnetic hydrodynamics and forcefree fields, the construction and the distribution of magnetic field and its energy in condensations are specifically discussed. Details on the coupling process between an unsteady plasma motion and a magnetic field are given. The coupling effect makes the energy in comet tails change into a force-free field in condensation, so that the magnetic field energy in the condensation continuously increases. Many phenomena observed in comet tails can be explained with the idea.
基金the National Natural Science Foundation of China(Grant No.11034002)the State Key Development Program for Basic Research of China(Grant No.2011CB921602)+2 种基金the Natural Science Program of Nantong University,Chinathe State Key Laboratory of Precision Spectroscopy,ChinaQing Lan Project,China
文摘A global analysis of the ro-vibrational spectra of 19 bands in the comet-tail （A2Πi-X2Σ＋） system of the 12C16O＋ cation is presented, and the precise molecular constants of the vibrational levels involved are obtained via a weighted nonlinear least-squares fitting procedure. Furthermore, the resultant precise equilibrium molecular constants enable us to achieve accurate Rydberg-Klein-Rees （RKR） potential curves for both the A and X states, yielding the accurate Franck-Condon factor and band origin of each band in this system.
基金theNationalNaturalScienceFoundationofChinaUnderGrant (No .199730 18& 196 5 30 0 1)
文摘In this paper, we adopted a reasonable particle distribution function and used a simplified judgement to analyze the possibility of the ion-pickup caused by two-stream instibility in cometary tail. On calculation, we get an energy limitation(ΔE 1, ΔE 2) between the solar wind particles and the cometary particles .When the energy diffference is between ΔE 1 and ΔE 2, the pickup of ions in the cometary tail is more effective.
文摘The velocity shear instability in a magnetized, three-component dusty plasma is investigated for both positively and negatively charged dust particles. The critical shears as a function of the relative charge of dust grains for both positively and negatively charged dust grains are in the same form. The instability excitation is easier in colder proton’s environment for positively charged dust, and so also in colder electron’s environment for negatively charged dust. For a certain flow pattern, the instability excites in different direction for different sign of charged dust grains. This conclusion may be helpful in interpreting the helical structures and streamer splitted phenomena in a cometary tail.
