Grain size of nanocrystalline YSZ buffer layers fabricated by ion beam deposition

Amorphous or nanocrystalline thin films are capable to be efficient diffusion barrier layers for YBCO coated conductors of ion beam assisted deposition route. Nanocrystalline Yttria-Stabilized Zirconia (YSZ) buffer layers were fabricated by the ion beam deposition. Kr and Ar gases were utilized for the dual Kaufman type sputtering ion sources sequently. Both of the ion beams were fixed at 200 mA, while the ion energy was in the range of 450–2000 eV. The thickness of the YSZ buffer layers was several hundreds of nanometers. The grain size of YSZ thin films, which varied from 2 to 20 nm, was calculated by Scherrer Formulation based on the X-ray diffraction measurement results. The grain size always decreased at first and then increased when the ion energy was increased. In the cases Kr gas was utilized and Ar gas was utilized, the grain size reached its minimum value at the ion energy of about 1800 eV and 1000 eV, respectively. Such phenomenon was discussed using the thermodynamic theory of thin film nucleation. Deposition rate and substrate temperature were the two chief variables of the critical nuclei concentration and grain size.     

Rational tuning of the rigidity of a ligand scaffold: synthesis of diphenylsulfide-linked bis(oxazoline) ligands and their application in asymmetric allylic alkylation

The scaffold rigidity of bis(oxazoline) ligands was rationally tuned on the basis of literature information. Diphenylsulfide-linked bis(oxazoline) ligands with a flexible scaffold were efficiently synthesized to test our hypothesis. The improved enantioselectivity in palladium-catalyzed asymmetric allylic alkylation reaction was achieved as we expected.     

Narrow linewidth continuous-wave and gain-switched fiber laser with intracavity unpumped Er-doped fiber loop

Investigation has been performed for the characteristics of the fiber ring laser incorporating an intracavity unpumped Er-doped fiber Sagnac loop for narrow linewidth continuous wave (CW) and gain-switched pulsed operation. The gain-switched pulse has duty cycle of 4.4% with more than 113 mW in peak power at the reflective optical filter output and the laser was stable both in output power and the peak wavelength.     

变频空调制冷系统流量调节性能分析和实验研究

通过实验分析不同膨胀阀开度和压缩机频率下系统性能。过热度在‘0’点及前后情况下,制冷系统性能及回油状况随膨胀阀开度调节,会出现较大变化。且在过热度为‘0’时系统制冷量和能效比最高。同时对不同频率下系统性能参数变化规律尤其是换热器效率影响进行分析。给出膨胀阀开度和压缩机变转速联合调节在系统性能最优状态下调节策略。     

Colorimetric Detection of Fe(II) and Co(II) by Using Terpyridine-Based Derivative

Journal of Applied Spectroscopy - A multi-ion chromogenic sensor based on a terpyridine moiety was developed for the semiquantitative, visual, and sensitive speciation analysis of Fe2+ and Co2+...     

Pair production of charged Higgs bosons in the left–right twin Higgs model at the ILC and LHC

The left–right twin Higgs (LRTH) model predicts the existence of a pair of charged Higgs bosons φ^±. In this paper, we study the production of the charged Higgs boson pair φ^± at the international linear collider (ILC) and the CERN large hadron collider (LHC). The numerical results show that the production rates are at the level of several tens fb at the ILC, and the process e⁺e^-→φ⁺φ^- can produce adequately distinct multi-jet final states. We also discuss the charged Higgs boson pair production via the process qq̄→φ⁺φ^- at the LHC and estimate in this case the production rates. We find that, as long as the charged Higgs bosons are not too heavy, they can be abundantly produced at the LHC. The possible signatures of these new particles might be detected at the ILC and LHC experiments. PACS 12.60.Fr; 14.80.Mz; 14.65.Ha; 12.15.Lk     

Influence of spacer layer thickness on the current-voltage characteristics of pseudomorphic AlAs/In0.53Ga0.47As/InAs resonant tunnelling diodes

This paper investigates the dependence of current voltage characteristics of AlAs/In0.53Ga0.47As/InAs resonant tunnelling diodes （RTDs） on spacer layer thickness. It finds that the peak and the valley current density J in the negative differential resistance （NDR） region depends strongly on the thickness of the spacer layer. The measured peak to valley current ratio of RTDs studied here is shown to improve while the current density through RTDs decreases with increasing spacer layer thickness below a critical value.