Multiple charge beam dynamics in Alternate Phase Focusing structure

Asymmetrical Alternate Phase (A-APF) focusing realized in a sequence of 36 Superconducting Quarter Wave Resonators has been shown to accelerate almost 81 % of input Uranium beam before foil stripper to an energy of 6.2 MeV/u from 1.3 MeV/u. Ten charge states from 34+ to 43+ could be simultaneously accelerated with the phase of resonators tuned for 34+. A-APF structure showed unique nature of large potential bucket for charge states higher than that of tuned one. Steering inherent to QWRs can be mitigated by selecting appropriate phase variation of the APF periods and optimization of solenoid field strengths placed in each of the periods. This mitigation facilitates multiple charge state acceleration schemeComment: 10 pages, 8 figure

Cs adsorption on Si(001) surface: ab initio study

First-principles calculations using density functional theory based on norm-conserving pseudopotentials have been performed to investigate the Cs adsorption on the Si(001) surface for 0.5 and 1 ML coverages. We found that the saturation coverage corresponds to 1 ML adsorption with two Cs atoms occupying the double layer model sites. While the 0.5 ML covered surface is of metallic nature, we found that 1 ML of Cs adsorption corresponds to saturation coverage and leads to a semiconducting surface. The results for the electronic behavior and surface work function suggest that adsorption of Cs takes place via polarized covalent bonding.Comment: 8 pages, 7 figure

The Chinese zombie firm: dilemma and resolution

The problems of over-capacity of zombie firms in China have attracted much attention. However, little is known theoretically, and even less empirically, about the boundaries and causes of zombie enterprises. This article extends a model to identify the characteristics of zombie firms in consideration of supply-side structural reform in China. We focus on the cause of zombie firms under the background of the ‘de-capacity’ strategy in China. Using a sample of Chinese listed companies over the period 2006–2018, we find that the proportion of zombie firms in the manufacturing industry declined significantly due to expansionary fiscal policy in 2011. Moreover, the structure of ownership, operational capabilities, and debt-paying ability co-varies positively, with state-owned enterprises being most prone to becoming zombie firms. The results allow us to construct various insights into how to govern the zombie firm. These results offer a frame for dealing with zombie firms. Our results are also robust in the sensitivity test of changing the measurement of zombie firms

Toolbox for entanglement detection and fidelity estimation

The determination of the state fidelity and the detection of entanglement are fundamental problems in quantum information experiments. We investigate how these goals can be achieved with a minimal effort. We show that the fidelity of GHZ and W states can be determined with an effort increasing only linearly with the number of qubits. We also present simple and robust methods for other states, such as cluster states and states in decoherence-free subspaces.Comment: 5 pages, no figures, v3: final version, to appear as a Rapid Communication in PR

Comparative performance of squeeze film air journal bearings made of aluminium and copper

This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. Copyright @ 2012 The Authors - The article can be accessed from the links below.This article has been made available through the Brunel Open Access Publishing Fund.Two tubular squeeze film journal bearings, made from Al 2024 T3 and Cu C101, were excited by driving the single-layer piezoelectric actuators at a 75-V AC with a 75-V DC offset. The input excitation frequencies were coincident with the 13th modal frequency, at 16.32 and 12.18 kHz for the respective Al and Cu bearings, in order to produce a ‘triangular’ modal shape. The paper also provided a CFX model, used to solve the Reynolds equation and the equation of motion, to explain the squeeze film effect of an oscillating plate with pressure end leakage. The dynamic characteristics of both bearings were studied in ANSYS and then validated by experiments with respect to their squeeze film thickness and load-carrying capacity. It was observed that whilst both bearings did levitate a load when excited at mode 13, the Al bearing showed a better floating performance than Cu bearing. This is due to the fact that the Al bearing had a higher modal frequency and a greater amplitude response than the Cu bearing.This article is made available through the Brunel Open Access Publishing Fund

The first operation and results of the Chung-Li VHF radar

The Chung-Li Very High Frequency (VHF) radar is used in the dual-mode operations, applying Doppler beam-swinging as well as the spaced-antenna-drift method. The design of the VHF radar is examined. Results of performance tests are discussed