Study on modes of energy action in laser-induction hybrid cladding

The shape and microstructure in laser-induction hybrid cladding were investigated, in which the cladding material was provided by means of three different methods including the powder feeding, cold pre-placed coating (CPPC) and thermal pre-placed coating (TPPC). Moreover, the modes of energy action in laser-induction hybrid cladding were also studied. The results indicate that the cladding material supplying method has an important influence on the shape and microstructure of coating. The influence is decided by the mode of energy action in laser-induction hybrid cladding. During the TPPC hybrid cladding of Ni-based alloy, the laser and induction heating are mainly performed on coating. During the CPPC hybrid cladding of Ni-based alloy, the laser and induction heating are mainly performed on coating and substrate surface, respectively. In powder feeding hybrid cladding, a part of laser is absorbed by the powder particles directly, while the other part of laser penetrating powder cloud radiates on the molten pool. Meanwhile, the induction heating is entirely performed on the substrate. In addition, the wetting property on the interface is improved and the metallurgical bond between the coating and substrate is much easier to form. Therefore, the powder feeding laser-induction hybrid cladding has the highest cladding efficiency and the best bond property among three hybrid cladding methods.     

小型天然气液化装置在我国天然气工业中的应用前景分析

天然气是一种洁净的能源,在国家环保安全和能源保障方面具有重要意义。液化天然气是天然气推广应用的重要形式。文中分析了小型天然气液化装置在我国天然气工业上游的零散气田和边远气田天然气、油田伴生气以及煤层气等领域和下游的液化天然气汽车和城市燃气调峰等领域的应用前景,指出小型天然气液化装置的应用将推动我国天然气工业的发展,为我国的能源结构调整和可持续发展发挥作用。     

Streaming potential analysis on the hydrodynamic transport of pressure-driven flow through a rotational microchannel

In this study, the streaming potential and electrokinetic energy conversion efficiency are discussed under the low zeta potential approximation through a microparallel channel with consideration of rotational effect. By solving Poisson-Boltzmann equation and modified Navier–Stokes equation, the analytical expressions of the streaming potential and electrokinetic energy conversion efficiency in the electrolyte solution are obtained. Combining with the numerical calculation, the influences of the dimensionless electrokinetic width K and the rotational angular velocity ω on streaming potential and the electrokinetic energy conversion efficiency are discussed. The results show that the streaming potential fields decrease both in mainstream and secondary directions with the electrokinetic width K, it decreases with the non-dimensional rotational angular velocity in the mainstream direction and it shows a first increasing then decreasing trend in the secondary flow direction. In addition, the influences of related non-dimensional parameters, including electrokinetic width, wall electric potential and rotational angular velocity, on the electrokinetic energy conversion efficiency are also discussed in detail. The rotating effect can enhance conversion efficiency comparing to the case of no rotation. The increase of wall electric potential gives rise to an augment in electrokinetic energy conversion efficiency. These theoretical results make sense to the energy harvesting in the rotating microfluidic systems.     

THE MACQM CALCULATION OF THE TOTAL ENERGY CURVE OF THE BODY-CENTERED CUBIC STRUCTURE OF THE H_9~- CLUSTER

ＴＨＥＭＡＣＱＭＣＡＬＣＵＬＡＴＩＯＮＯＦＴＨＥＴＯＴＡＬＥＮＥＲＧＹＣＵＲＶＥＯＦＴＨＥＢＯＤＹ－ＣＥＮＴＥＲＥＤＣＵＢＩＣＳＴＲＵＣＴＵＲＥＯＦＴＨＥＨ－９ＣＬＵＳＴＥＲＧｏｕＱｉｎｇｑｕａｎＺｈａｎｇＪｉａｎｐｉｎｇＬｉＰｉｎｇＩｎｓｔｉｔｕ...     

Notations, Spectroscopic Parameters, Energy Levels and Their Relationship to Effective Hamiltonian Formalism of Diatomic Molecules

This paper presents a part of the culmination of the collective efforts in developing a cohesive and consolidated enunciation of the spectroscopic parameters and their relationship to effective molecular Hamiltonians for diatomic formalism, linear four-atomic formalism and quasi-linearity, Watson Hamiltonian and the complexities in symmetric and asymmetric top spectral structures. All these considered together present a beautiful and consistent picture of molecular spectroscopy. In this paper we deal with the diatomic formalism. This paper forms our tribute to Professor K. Narahari Rao and in the second part of the paper we convoy our gratitude to him with a summary of his more than half century of work and an obituary. We will deal with other forms of molecular species which will be connected to optical pumping and/or interstellar space.     

Electron–hole recombination luminescence in LiYF4:U single crystal

Photoluminescence (PL), photostimulated luminescence (PSL), thermally stimulated luminescence (TSL) and electron paramagnetic resonance (EPR) studies were carried out on LiYF₄:U⁴⁺ and pure LiYF₄ crystals. The PL and EPR investigations have identified the presence of Eu³⁺, Tb³⁺ and Gd³⁺ ions in both of these crystals possibly due to their existence in the starting materials. The luminescence observed during afterglow, PSL and TSL revealed that emission occurs at wavelength positions 382, 413, 437 and 544 nm, which are characteristic of Tb³⁺ ions. The present investigations using PSL and TSL in combination with PL studies before and after gamma irradiation have revealed that selective energy transfer to Tb³⁺ ions occurs during electron–hole recombination processes like PSL and TSL. Even though other luminescent ions (U⁴⁺ and Eu³⁺) are present in the system and U⁴⁺/U³⁺ ions are participating in electron capture/release processes, the selective energy transfer results in Tb³⁺ ions acting as luminescence centers.     

低阻抗二极管产生的强流电子束能谱分布的数值模拟

 给出了低阻抗二极管产生的电子束能谱分布及外加磁场对二极管阻抗影响的数值模拟研究结果。结果表明，即使在外加电压恒定的条件下，二极管产生的电子束也具有一定的能谱分布，这说明用二极管电压、电流波形计算脉冲电子束能谱分布是不正确的。另外,外加磁场对低阻抗二极管的阻抗特性具有较大影响，其阻抗随外加磁场的增大而减小。分析认为这是由于外加磁场强度的变化改变了二极管中束电子的运动轨迹。当没有外加磁场或外加磁场较小时，低阻抗二极管产生的电子束发生自箍缩，此时二极管电流是自箍缩饱和顺位流；当外加磁场足够强时，电子束的自箍缩被抑制，二极管电流是没有箍缩时的空间电荷限制电流。束电流小于自箍缩临界电流的二极管其阻抗将不随外加磁场的变化而变化。     

高剥离类镁等电子序列的磁偶极M1和电四极E2光谱跃迁理论研究

利用全相对论性多组态Dirac-Fock广义平均能级方法，系统地计算了类镁离子3s3p磁偶极Ml^3P2--^3P1和电四极E2 ^2P2--^3P0(Z=20-103)光谱跃迁的能级间隔、跃迁几率和振子强度。计算中考虑了原子核的有限体积效应，进行了高阶Breit修正和QED修正，所得到的能级间隔和最近的实验数据及理论计算值进行了比较。计算结果表明：高原子序数的高荷电离子的磁偶极矩M1和电四极矩E2跃迁几率和中性原子的电偶极E1的相当，在ICF和MCF高温激光等离子体中，磁偶极矩M1和电四极矩E2跃迁过程不容被忽视。     

单模石英光纤中连续波泵浦SRS谱的演化

利用连续波掺Yb双包层光纤激光器为泵浦源,对单模石英光纤中受激Raman散射谱的形成过程进行了实验研究结果表明,由自发Raman散射向受激Raman散射演化的过程中Stokes谱宽度不断变窄当Stokes波信号功率较强时,在Raman光谱内部会出现能量红移现象,使Stokes光谱峰值相对于泵浦波的频移量从440cm^-1转化到490cm^-1.     

Energy transfer studies in dye mixtures in different solvent environments

The energy transfer mechanism in C 540–rhodamine 6G and C 540–rhodamine B donor–acceptor (D–A) pairs is investigated. The good spectral overlap and the proximity of D–A pair molecules, which is around 60 Å, denote the possibility of resonance energy transfer between the D–A pairs. Energy transfer is studied in two solvent environments. C 540–Rh 6G and C 540–RhB D–A pairs behave in quite different manner in different solvent environments.