Bi2Sr2CaCu2O8单晶S-N转变的E-J特性

我们应用脉冲电流的方法测量了Bi2Sr2CaCu2O8单晶在4特斯拉强场下的大电流时等温E－J特性,我们观察到在大电流时,样品电阻率ρ迅速增大,随着电流的继续上升,经过一段正曲率增长阶段,几乎达到饱和值,最后经过一段负曲率上升,达到正常态,显示出完整的S形,应用尹道乐等人的统一物质方程理论,给出了实验曲线较好的数值拟合,根据拟合结构,讨论了理论中各个参量的物理意义。     

Sn60Pb40钎料合金的具有蠕变和塑性边界的粘塑性本构方程

采用具有蠕变和塑性边界的粘塑性本构方程对Sn-Pb共晶合金的基本力学行为进行了模拟和预测。结果表明：在较宽的外部变量范围（应变率为10^-5-10^-2S^-1,温度为－55－125℃）内,模拟结果与实验结果吻合良好。证明了该方程用于描述Sn-Pb共晶合金的力学行为具有良好的预测能力。     

宽带脉冲DC SQUID核磁共振谱仪的研制

DC SQUID NMR在研究凝聚态体系 ,尤其在研究低温下量子有序态等方面是一项非常有价值的技术。文中描述了在带有宽带电子设备的商业 DC SQUID基础上建立起宽带脉冲谱仪 ,以及马鞍形激发线圈、采集线圈和低温装置的设计 ,并测量了铂样品在 4.2 Kz温度下的 NMR信号。     

生物大分子纳米孔分析技术研究进展

脱氧核糖核酸穿越纳米孔动力学研究以及利用纳米孔开展新型DNA测序技术研究是后人类基因组计划的热点之一。本文对生物纳米孔、固态纳米孔以及纳米孔生物大分子识别技术的研究现状进行了归纳和总结,并对该领域的发展趋势进行展望。     

Single long-polymer translocation through a long pore

This paper theoretically studies the free energy and conformational entropy of a long polymer threading a long nanopore （no/N ≥0.1） on external electric field. The polymer expanded model is built in this paper, that is, a single long polymer chain with N monomers （each of size a） threading a pore with no monomers can be regarded as polymer with N ＋ no monomers translocating a 2-dimension hole embedded in membrane. A theoretical approach is presented which explicitly takes into account the nucleation theory. Our calculations imply that, the structure of polymer changes more acutely than other situation, while its leading monomer reaches the second vacuum and its end monomer escapes the first vacuum. And it is also shown that the length scale of polymer and pore play a very important role for polymer translocation dynamics. The present model predicts that the translocation time depends on the chemical potential gradient and the property of the solvent on sides of pore to some extent.     

Elaborate calibration procedure for cell irradiation at the CAS-LIBB single-particle microbeam

Single-particle microbeam is uniquely capable of precisely delivering a preset number of charged particles to individual cells or sub-cellular targets to be determined in vitro, It is crucial to find a reference point that relates the microbeam＇s location to the microscope＇s plane, and align individual targets at this reference point for cell irradiation. To choose an appropriate reference point, an approach based on analysing the intensity distribution of fluorescence in a thin scintillator excited by traversing particles is newly developed using the CAS-LIBB single-particle microbeam, which features decisive physical signification and sufficient resolution. As its bonus, this on-line analysis provides precise and fast response to the determination of beam profile and potentially optimizes the microbeam quality by further adjusting hardware setup.     

准一维介观铝超导线的电阻振荡

介观铝超导线的特性近来被广泛研究,有关反常微分电阻的实验和理论研究工作都取得了不小的进展。特别是此前报道的在附加射频信号时,介观铝超导线出现的电阻－温度曲线的振荡现象尤为引人注目。我们通过电子束刻蚀法制作了准一维介观铝线。我们在没有附加任何条件下,观测到正常态（N）和超导态（S）转变温度附近电阻－温度曲线在小测量电流时出现振荡。这种振荡的产生可能是由于电压探头之间铝线中的N／S界面的数目随温度变化造成的。