Improvement of SFC

The Heavy Ion Research Facility at Lanzhou (HIRFL) is a cyclotron complex in which a Sector Focusing Cyclotron (SFC) with energy constant K=69 as an injector was converted from the original existing conversional cyclotron with diameter 1.5 m. In the process of operation for about 20 years, some shortages were exposed. For example, the vacuum pressure of SFC is only 10^-4 Pa magnitude, in the case most of the heavier ions will be lost in it. Because the yoke of SFC was not changed in the fabricated process, while the diameter of accelerator is changed from 1.5 m to 1.7 m, so the magnetic saturation is very serious in the yoke. The stay magnetic field around the cyclotron is very strong. It affects not only the beam tuning in vertical process coming from ECR ion source, but also the extraction beam behind SFC. The performance of RF system is worse than that before because of long time operation, so it is difficult to obtain satisfactorv Dee voltage.     

The Study of Fueling Method and Particle Confinement Improvement

Several high performance tokamak operation regimes have been achieved experimentally in the experiments with the peaked density profiles. The regimes include the improved Ohmic confinement in ASDEX, the pellet enhanced performance mode in Alcator-C, and the super-shot mode in TFTR. In these regimes, peaked core density profiles are always existent, and almost always go with the internal transport barriers, these barriers generally produced by sheared radial electric field. In addition to enhance confinement, the peaked density profile is also needed for the optimized fusion reaction rate and alpha heating power in tokamak plasma, and combined peaked density profile and peaked temperature profile, would make the ignition condition easy obtained. It is desirable to seek and analyze the density profile control schemes that effectively lead to density profile peaking in particle transports experimental investigation.     

Bell’s Inequalities and Methods of Quantifying Measures of Entanglement Correlations

Bell inequalities provide a specific setting for investigating the physics of entanglement in quantum mechanics. They give a basis for providing an experimental realization of these kinds of quantum phenomena and exhibit some of its more unusual consequences. Some useful ways to look at entanglement quantitatively are presented. It is intended that the presentation and results will provide insights which make effective experimental observation easier.     

Improvement of Synchronizability of Scale-Free Networks

We investigate the factors that affect synchronizability of coupled oscillators on scale-free networks. Using the memory Tabu search （MTS） algorithm, we improve the eigen-ratio Q of a coupling matrix by edge intercrossing. The numerical results show that the synchronizatlon-improved scale-free networks should have distinctive both small average distance and larger clustering coefficient, which are consistent with some real-world networks. Moreover, the synchronizability-improved networks demonstrate the disassortative coefficient.     

Inseparable Criterion and Bell Inequality

In this letter, we shall show how to construct constrained Bell-type inequality for a general two-party system, and violating this inequality is equivalent to being inseparable. For 2 × 2 system, the maximum violation is 3, while for 3 × 3 system, the largest violation is 11/3.     

The relation between Hardy’s non-locality and violation of Bell inequality

We give an analytic quantitative relation between Hardy’s non-locality and Bell operator. We find that Hardy’s non-locality is a sufficient condition for the violation of Bell inequality, the upper bound of Hardy’s non-locality allowed by information causality just corresponds to Tsirelson bound of Bell inequality and the upper bound of Hardy’s non-locality allowed by the principle of no-signaling just corresponds to the algebraic maximum of Bell operator. Then we study the Cabello’s argument of Hardy’s non-locality (a generalization of Hardy’s argument) and find a similar relation between it and violation of Bell inequality. Finally, we give a simple derivation of the bound of Hardy’s non-locality under the constraint of information causality with the aid of the above derived relation between Hardy’s non-locality and Bell operator.     

Improvement of microstructure and magnetic properties of Nd–Fe–B alloys by Nb and Co additions

In order to establish the role of niobium on the hydrogenation, disproportionation, desorption and recombination (HDDR) behavior of near-stoichiometric alloys, two alloys: NdI3Fe8OB7 and Nd13Fe78Nb1Co1B7 (at%) were investigated before, during and after the HDDR process. The microstructure of the as-cast Nb-free alloy before employing the HDDR process was found to consist of three phases, the matrix Nd₂Fe₁₄B (φ) phase, Nd-rich phase and a significant amount of free iron; whereas, the microstructure of the Nb-containing alloy consisted of only the first two phases.     

On the implication of Bell’s probability distribution and proposed experiments of quantum measurement

In derivating of Bell’s inequalities, the probability distribution is supposed to be a function only of a hidden variable. We point out that the true implication of the probability distribution of Bell’s correlation function is the distribution of joint measurement outcomes on the two sides. It is therefore a function of both the hidden variable and the settings. In this case, Bell’s inequalities fail. Our further analysis shows that Bell’s locality holds neither for dependent events nor for independent events. We think that the measurements of EPR pairs are dependent events, and hence violation of Bell’s inequalities cannot rule out the existence of local hidden variable. To explain the results of EPR-type experiments, we suppose that a polarization-entangled photon pair can be composed of two circularly or linearly polarized photons with correlated hidden variables, and a couple of experiments of quantum measurement are proposed. The first uses delayed measurement on one photon of the EPR pair to demonstrate directly whether measurement on the other could have any nonlocal influence on it. Then several experiments are suggested to reveal the components of the polarization-entangled photon pair. The last one uses successive polarization measurements on a pair of EPR photons to show that two photons with the same quantum state behave the same under the same measuring conditions.     

The relation between and violation of Hardy＇s non-locality Bell inequality

We give an analytic quantitative relation between Hardy＇s non-locality and Bell operator. We find that Hardy＇s non-locality is a sufficient condition for the violation of Bell inequality, the upper bound of Hardy＇s non-locality allowed by information causality just corresponds to Tsirelson bound of Bell inequality and the upper bound of Hardy＇s non- locality allowed by the principle of no-signaling just corresponds to the algebraic maximum of Bell operator. Then we study the CabeUo＇s argument of Hardy＇s non-locality （a generalization of Hardy＇s argument） and find a similar relation between it and violation of Bell inequality. Finally, we give a simple derivation of the bound of Hardy＇s non-locality under the constraint of information causality with the aid of the above derived relation between Hardy＇s non-locality and Bell operator.     

A comment on “critique of home and sengupta's derivation of a Bell inequality”

We clarify some aspects of our derivation of a Bell-type inequality, in response to a paper by Elby.The following comments refer to Andrew Elby's discussion note immediately following our present paper.(a) We wish to stress that physical distinction between NC and LC is particularly important in the case of local realist theories violating NC for any single system but satisfying LC for any correlated many-component system. Arguments given by Elby do not rule out a reasonable theory violating NC but obeying LC. Therefore, a physically meaningful possibility exists that while Bell's inequality derived from NC is violated for a single system, the inequality derived from LC is satisfied for correlated and spatially separated (non-interacting) systems. It is precisely this possibility which was explored by HS in deriving Bell's inequality from NC.(b) Since Elby's formulation of locality condition necessarily involves a relativistic constraint at the level of individual measurements, it is pointless to discuss its compatibility with predictions derived from non-relativistic quantum mechanics, which is well known to allow superluminal communication by mechanisms such as wavepacket travel or spread. Recently this aspect has been discussed in depth by P. Ghose and D. Home,Phys. Rev. A 43, 6382 (1991). It needs to be stressed that our formulation of LC is in line with the separability condition articulated by Einstein in different contexts; see, for example,J. Franklin Inst. 221, 349 (1936), reprinted inIdeas and Opinions (Crown, New York, 1954), pp. 290–323.On leave from: Department of Physics, Bose Institute, Calcutta 700009, India.     

Bell’s Correlations and Spin Systems

The structure of maximal violators of Bell’s inequalities for Jordan algebras is investigated. It is proved that the spin factor V ₂ is responsible for maximal values of Bell’s correlations in a faithful state. In this situation maximally correlated subsystems must overlap in a nonassociative subalgebra. For operator commuting subalgebras it is shown that maximal violators have the structure of the spin systems and that the global state (faithful on local subalgebras) acts as the trace on local subalgebras.     

Improvement of Surface Porosity and Properties of Alumina Films by Incorporation of Fe Micrograins in Micro-arc Oxidation

Micro-arc oxidation （MAO）, a plasma electrolytic surface process, has attracted much interest as an effective technique to improve the wear resistance of aluminum alloys by creating a relatively thick and hard alumina coating on the component surface. However, previous studies of MAO aluminum alloys have shown that as-deposited and polished alumina coatings have a relatively high friction coefficient, for example, values of 0.6 and 0.7 against WC/Co and AISI 52100 counterfaces in dry sliding tests, respectively.     

Performance Improvement of Distributed and Discrete Raman Amplifiers with a Fibre Loop Mirror

We use a fibre loop mirror to reflect the residual pump power (RPP) into the fibre for solving the problems of the RPP in Raman amplifiers. The experimental results show that the novel hi-directional pumping scheme without adding extra pump lasers is effective, and higher gain and lower noise are obtained for both the distributed and the discrete Raman amplifiers.     

Improvement of Main Magnetic Field Power Supply of SFC

The main magnetic field power supply is used for establishing main magnetic field of SFC, therefore excellent current stability and low ripple are required. Its DC output current range is 0～1300 A and max output voltage is 230 V. The power supply has been put into operation since Sep. in 2000, and was replaced in 033 room from 166 room of No.2 Building. We have improved the performance of power supply in this period.     

Improvement of Properties of p-GaN by Mg Delta Doping

The Mg-delta-doped GaN structure has been grown by low-pressure metalorganic chemical vapour deposition.The Hall-effect measurements reveal that the electrical properties are enhanced. The hole concentration is enhanced twice and hole mobility is enhanced three times by Mg-delta doping. Both the etch pit density data and the x-ray diffraction data demonstrate that Mg-delta doping can reduce the threading dislocation density of p-type GaN epilayer.     

Cryptanalysis and Improvement of a Multi-User Quantum Communication Network Using χ-Type Entangled States

The security of a multi-user quantum communication network protocol using χ-type entangled states (Chang et al., J. Korean Phys. Soc. 61:1–5, 2012) is analyzed. We find that, by using one χ-type state in this protocol, two participants can only share 2 bits of information, not 4 bits as the authors stated. In addition, we give a special attack strategy by which an eavesdropper can elicit half of the secret information without being detected. Finally, we improve the protocol to be secure against all the present attacks.