Light-induced metastable state in doping-modulated amorphous silicon superlattices

Photo-induced decrease in conductance after long light exposure has been observed for hydrogenated amorphous silicon (a-Si:H) npnp . doping-modulated superlattices showing large persistent photoconductivity (PPC). The initial increase in PPC is taken over by the decrease even to the negative PPC after long illumination. This light-induced, metastable conductance can be recovered completely by 160°C annealing, which is independent of exposure time. In particular, the metastable defects created in the p-layers are found to be annealed out at 100°C. The subband gap light exposure on the a-Si:H npnp. multilayers showing n-type conduction gives rise to the increase of conductance. On the contrary, the conductance of the multilayers having p-channel conduction decreases by IR exposure. These results strongly suggest the creation and annealing of dangling bonds by light-soaking and annealing in doping-modulated superlattices.     

Intercalation dans le graphite du sulfure et du séléniure de potassium

The reaction between graphite and liquid potassium, containing small amounts of sulphur or selenium, leads to the synthesis of new lamellar compounds, of which the three-layered intercalated sheets can be regarded as potassium sulfide or selenide slices, being arranged between the graphene planes. These slices retain the hexagonal symmetry that they possess in the 3D binary chalcogenides, thanks to some adaptations. Particularly, they become commensurate with respect to the graphene planes.     

Heat capacity of a current carrying superconductor

We present an analysis of the heat capacity of a superconductor carrying a constant applied electric current. We find that the heat capacity diverges with an exponent of 0.5 at a depressed transition temperature. This result is similar to a recent calculation of the heat capacity of superfluid helium under an applied heat current.     

Hysteresis and avalanches in the site-diluted Ising model: comparison with experimental results in Cu–Al–Mn alloys

We study the zero temperature properties of hysteresis in a site-diluted Ising model. The model exhibits a critical line separating a disordered from an incipient ferromagnetic ground state: the shape of the hysteresis loop changes from a smooth cycle (formed as a sequence of tiny avalanches) to a sharp cycle exhibiting a macroscopic reversal of the magnetization for a given value of the field (infinite avalanche). Criticality is characterized by power-law distribution of avalanche sizes. Model predictions are contrasted with experimental results obtained in Cu–Al–Mn alloys.     

Bioelectrochemical Response of Polypyrrole Modified Urease Sensor

The preparation method of biological ferment electrode is one of decisive factors that affect its bio-electrochemical responding sign. It demands both suitable indicator electrode and antiwater soluble film that can keep catalytic activity. In this paper,urease was doped into polypyrrole(PPy) film while pyrrole(Py) was polymerized by electrochemical method to formed urease biosensor based on PPy film,then,ferment electrode was combined with CO₂ gas-sensing electrode to assemble a urease biosensor responding to urea.     

7MeV注入剥离膜系统设计

设计了一台注入能量为7 MeV的快循环同步加速器剥离膜装置,介绍了主体结构设计及高精度换膜运动结构,实现膜片精确定位及在线换膜功能。针对注入参数对膜片开展分析计算,分析了7 MeV的负氢离子束注入时相应的碳膜材料的反应截面及不同厚度的剥离效率,给出了膜片厚度的参数选择。对所设计膜片的温升和寿命进行分析,膜片的温升最高点达到755 K,远小于同类的加速器的剥离膜温度,具有更高的寿命和可靠性。     

Reply to the comment on “On the Barut-Vigier model of the hydrogen atom”

It is shown that the main conclusion of Dragić and Marić [Phys. Lett. A 229 (1997) 130] about the ground state of the hydrogen atom in the Barut-Vigier potential is based on the wrong use of the radial wave function which cannot be normalized.     

Repulsion forces in vibrational spectroscopy—I. Spectral shifts in vibrational spectra of condensed media caused by repulsion forces

Repulsional contributions into spectral shifts have been expressed in terms of derivatives of atom displacements with respect to vibrational normal coordinates. Attraction and repulsion have been shown to give a comparable contribution to the overall shift. Working ability of the formulae obtained for spectral shift calculations for molecular (HCl solution in CCl₄) and ionic (molten lithium and rubidium nitrates) liquids is demonstrated.     

非晶合金剪切带动力学行为研究

剪切带是一种材料塑性变形高度局域化的变形模式, 广泛存在于非晶体系的形变中, 控制着这些无序体系失稳、灾难性断裂行为.传统的非晶体系如岩石, 胶体, 玻璃和聚合物等因较差的力学性能以及过于复杂的结构而不利于剪切带的实验研究. 近几十年来, 非晶合金的出现极大丰富了剪切带的研究, 推进了对剪切带的认识. 通过大量非晶合金中剪切带的实验和理论研究, 人们发现剪切带行为具有空间不均匀性和时间不连续性的特征, 表现出复杂的动力学特征, 和自然界以及物理系统中许多复杂体系的动力学行为相似.同时, 剪切带的性质尤其是其动力学行为对非晶合金的宏观力学行为和性能有重要的影响, 对理解这类材料的微观变形机理也起着重要的作用.本文结合团队近年来在非晶合金剪切带行为方面的研究结果, 对剪切带的运动行为和物理机制进行介绍, 包剪切带间歇性运动行为、以及间歇性运动在表征其动力学性质中的作用以及物理机制, 以及剪切带的自组织临界行为、物理机制等.最后对非晶合金剪切带行为研究中亟需解决的问题进行了总结和展望.