核耗散强度对超重核蒸发剩余截面的影响

尽管目前利用熔合蒸发反应合成超重核的研究陷入停顿,但该反应机制仍是实验室合成新核素的主要方法.为了研究核耗散强度对超重核素合成截面的影响,通过冻结能级密度参数及其在鞍点和基态处的比值,对超重元素Cn、Fl和Lv的7个反应进行了数值计算.计算结果表明重现实验数据所需核耗散强度随超重余核质量数的减小而逐渐减弱.此外,相比于对282,283Cn和292,293Lv的模拟,要重现新质子幻数Z=114对应的超重复合核287,288,289Fl的实验数据则需要增强核耗散强度.上述规律为获取超重核的结构信息提供了一种潜在的核反应学方法.

核耗散强度对角动量的可能依赖性(英文)

对130MeV3He+natAg→110,112In和890以及714MeV 84Kr+27Al→111In反应中的核耗散行为进行了一个比较分析．数据分析建议除了已知的温度和／或形变依赖性以外,核耗散强度可能对角动量也存在一定的依赖性．

含虚拟惯量的双馈风电机组动态能量模型及振荡稳定性研究

针对含虚拟惯量的双馈风电并网系统振荡稳定问题,从动态能量的角度揭示了虚拟惯量对双馈风电机组(doubly fed induction generator,DFIG)参与系统振荡的作用机理。首先,构建了不同振荡模态下含虚拟惯量双馈风电机组的动态能量模型,并探究了虚拟惯量直接和间接通过锁相环影响机网耦合的能量通道。在此基础上,定义了耗散强度指标,表征双馈风电机组对各振荡模态的耗散作用,并分析了不同接入位置、不同控制参数、不同振荡模态下虚拟惯量通过各能量通道对双馈风电机组耗散强度以及机网耦合作用的影响,揭示了含虚拟惯量风电机组与网侧能量交互诱使系统振荡发散的作用机理。最后,以IEEE四机两区系统进行实时数字仿真(Real Time Digital Simulator,RTDS)仿真验证,结果表明:当锁相环(phase-locked-loop,PLL)自激振荡模态与网侧机电振荡模态频率相距较远时,含虚拟惯量风机接入送端区域产生负耗散作用,接入受端区域产生正耗散作用。当PLL自激振荡模态与网侧机电振荡模态频率接近时,受模态强耦合共振影响,风机通过锁相环自耦合能量通道和虚拟惯量能量通道与电网强交互,产生负耗散作用,且在模态频率重合时达到极大值。

Low cyclic fatigue performance of concrete-filled steel tube columns

Eight concrete-filled steel tubular(CFT) columns were tested subjected to cyclic loading under constant axial load. Experimental parameters included axial compression ratio, loading sequences, and strength of concrete and steel. The seismic performance of CFT columns and failure modes were analyzed. The test results show that different axial load ratios and loading sequences have effects on the load carrying capacity, ductility and energy dissipation capacity of CFT columns, as well as the failure modes of the CFT columns. The failure pattern can be categorized into two types: local buckling failure of steel tube in compression zone, and low cycle fatigue tearing rupture failure of steel tube. The seismic behavior was evaluated through the energy index obtained from each cycle.

Study on Hydrography and Small-Scale Process over Zhoushan Sea Area

This paper mainly analyzes the tidal characteristics and small-scale mixing process near Zhoushan Islands. First, the spectral analysis and wavelet analysis are adopted for the measured tide level data and tidal current data from the Zhoushan sea area, which indicate that the main tidal cycle near Hulu Island and Taohua Island is semi-diurnal cycle, the diurnal cycle is subordinate. Both their intensities are changed periodically, meanwhile, the diurnal tide becomes stronger when semi-diurnal tide becomes weak. The intensity of baroclinie tidal current weakens at first and then strengthens from top to bottom. Then, in this paper, the Gregg-Henyey （G-H） parameterization method is adopted to calculate the turbulent kinetic energy dissipation rate based on the measured temperature and tidal current data. The results of which shown that the turbulent kinetic energy dissipation rate around Hulu Island is higher than that around Taohua Island. In most cases, the turbulent kinetic energy dissipation rate during spring tide is larger than that during the neap tide; the turbulent kinetic energy dissipation rate in the surface layer and the bottom layer are higher than that in the intermediate water; the changes of turbulent kinetic energy dissipation rate and tidal current are basically synchronous The modeled turbulent kinetic energy dissipation rate gets smaller with the increase of the stratification, however, gets larger with the increase of shearing.

同位旋对轻系统裂变前粒子发射的影响

在Smoluchowski方程的框架内 ,研究了同位旋对轻裂变同量异位素源110 Tc ,110 Pd ,110 In和同位素源110 ,117,12 4In裂变前粒子发射的影响 .计算结果表明 :断前粒子发射对裂变源的同位旋有很强的依赖性 ,随着同位旋的增加 ,中子发射增强 ,而轻带电粒子则减弱 ;对一个高同位旋的系统 ,质子和α粒子不适合作为提取核耗散强度的实验观测量 ;