Calculation of triaxial superdeformation in <Superscript>174</Superscript>Hf

A two-dimensional Total Routhian Surface (TRS) calculation with the fixed hexadecapole deformation ε4 = 0.03 was carried out for several configurations of 174Hf. Results indicate that the shell corrections have an important contribution to the formation of triaxial superdeformation in 174Hf and some possible configuration assignments are made to the 4 TSD bands experimentally found in 174Hf.     

Mixed symmetry states and isospin excitation in <Emphasis Type="Italic">N</Emphasis> = <Emphasis Type="Italic">Z</Emphasis> nucleus <Superscript>52</Superscript>Fe

The interacting boson model with isospin (IBM-3) was applied to study the band structure and electromagnetic transition properties of the low-lying states in the even-even N = Z nucleus ⁵²Fe. The isospin excitation states with T = 0, 1 and 2 were identified, and compared with the available data. The study shows that the 2₃⁺ state is the lowest mixed symmetry state in ⁵²Fe. The excitation energy of the second 0₂⁺ state with T = 0 in nucleus ⁵²Fe was identified. The model calculations with the data show a reasonably good agreement. Supported by the National Natural Science Foundation of China (Grant Nos. 10765001 and 10547003), the Natural Science Foundation of Inner Mongolian Autonomous Region of China (Grant No. 200607010111), and the Scientific Research Fund of Inner Mongolian Education Bureau (Grant Nos. NJZY07155 and NJZY07153)     

Near infrared lights emission of <Superscript>40</Superscript>Ar<Superscript>16+</Superscript> impacting on metal surfaces

The highly charged ion ⁴⁰Ar¹⁶⁺ with the velocity (kinetic energy E _K=150 keV, velocity V=8.5×10⁵ m/s) smaller than Bohr velocity (V _Bohr=2.9×10⁶ m/s) was found to hove impacts on the surfaces of metals Ni, Mo, Au and Al, and the Ar atomic infrared light lines and X-rays spectra were simultaneously measured. The experimental results show that the highly charged ion that captures electrons is neutralized, and the multiply-excited hollow atom forms. The hollow atom cascade decay radiates lights from infrared to X-ray spectrum. The intensity of infrared lights shows that the metallic work functions play an important role in the neutralization process of highly charged ions during their interaction with metallic surfaces, which verifies the classical over-the-barrier model. Supported by the National Natural Science Foundation of China (Grant No. 10574132), the Natural Science Foundation of Shaanxi Province (Grant No. 2007A05) and the Talents Introduction Project of Xianyang Normal University (Grant No. 05XSYK103)     

X-ray spectra induced by <Superscript>129</Superscript>Xe<Superscript><Emphasis Type="Italic">q</Emphasis>+</Superscript> impacting the metal surface

Using the slow highly charged ions ¹²⁹Xe ^q+ (q = 25, 26, 27; initial kinetic T ₀⩽4.65 keV/a.u.) to impact Au surface, the Au atomic Mα characteristic X-ray spectrum is induced. The result shows that as long as the charge state of projectile is high enough, the heavy atomic characteristic X-ray can be effectively excited even though the incident beam is very weak (nA magnitude), and the X-ray yield per ion is in the order of 10⁻⁸ and increases with the kinetic energy and potential energy of projectile. By measuring the Au Mα-X-ray spectra, Au atomic N-level lifetime is estimated at about 1.33×10⁻¹⁸ s based on Heisenberg uncertainty relation. Supported by the National Natural Science Foundation of China (Grant Nos. 10574132, 10274088 and 10405025), the Talent Introduction Project of Xianyang Normal University (Grant No. 05XSYK103) and the Education Commission Foundation of Shaanxi Province (Grant No. 04JK300)     

Further research on high-spin structure in 161Lu

The two-dimensional total routhian surface (TRS) calculations were performed to probe into the triaxial superdeformed characteristics of a strongly populated band X2 in ¹⁶¹Lu. This band was identified as a triaxial superdeformed band by using our TRS method. We also got its formation mechanics, i.e. the neutron-shell correction energy plays a crucial role, while the rotating energy and the deformation-driving effect of high j intruder orbit i _13/2 also play an additional role. Supported by the National Natural Science Foundation of China (Grant Nos. 10575036 and 10675046) and the Natural Science Foundation of Zhejiang Province of China (Grant Nos. Y604027 and Y605476)     

δ/γ transformation in non-equilibrium solidified peritectic Fe-Ni alloy

Through phase transformation kinetic analysis and experimental observation, the δ/γ transformation occurring in the non-equilibrium peritectic Fe-4.33at.%Ni alloys was systematically investigated. According to JMA solid-state transformation kinetic theory, the Time-Temperature-Transformation (TTT) curves of the δ/γ transformation in peritectic Fe-Ni alloy were calculated. On this basis, the physical correlation between the δ/γ transformation and the initial undercooling of melt (△T) was elucidated. The results indicate that the change of △T can alter not only the overall δ/γ transformation pathways but also the transformation fraction with respect to each transformation mechanism.     

<Emphasis Type="Italic">In situ</Emphasis> X-ray diffraction study of structural evaluation in Fe<Subscript>73</Subscript>Cu<Subscript>1.5</Subscript>Nd<Subscript>3</Subscript>Si<Subscript>13.5</Subscript>B<Subscript>9</Subscript> amorphous alloy at high temperature

The thermodynamics structural relaxation of Fe₇₃Cu_1.5Nd₃Si_13.5B₉ amorphous alloy from room temperature to 400°C has been investigated by measuring the structure factor with in situ X-ray diffraction. The structural information of the atomic configuration such as radial distribution function (RDF) and neighbor atomic distance was gained by Fourier transformation. The research result shows that the amorphous structure remains stable in the temperature range of 30 to 400°C but exhibits distinct changes in local atomic configuration with the increase of temperature. The quantitative determination of the neighbor atomic distance suggests that the degree of short-range order changes by the temperature altering the second nearest neighbor local atomic configuration of the amorphous when structural relaxation occurs. Supported by the Natural Science Foundation of Hebei Province of China (Grant No. A2007000296), the National Natural Science Foundation of China (Grant No. 50731005), SKPBRC (Grant Nos. 2007CB616915 and 2006CB605201), and PCSIRT (Grant No. IRT0650)     

Wavelength and oscillator strength of dipole transition 1s<Superscript>2</Superscript>2p—1s<Superscript>2</Superscript><Emphasis Type="Italic">n</Emphasis>d for Mn<Superscript>22+</Superscript> ion

The transition energies, wavelengths and dipole oscillator strengths of 1s²2p—1s² nd (3⩽n⩽9) for Mn²²⁺ ion are calculated. The fine structure splittings of 1s² nd (n</9) states for this ion are also evaluated. In calculating energy, the higher-order relativistic contribution is estimated under a hydrogenic approximation. The quantum defect of Rydberg series 1s² nd is determined according to the quantum defect theory. The results obtained in this paper excellently agree with the experimental data available in literatures. Supported by the National Natural Science Foundation of China (Grant No. 10774063)     

Generalized two-mode coherent-entangled state with real parameters

The coherent-entangled state |α, x; λ> with real parameters λ is proposed in the two-mode Fock space, which exhibits the properties of both the coherent and entangled states. The completeness relation of |α, x; λ> is proved by virtue of the technique of integral within an ordered product of operators. The corresponding squeezing operator is derived, with its own squeezing properties. Furthermore, generalized P-representation in the coherent-entangled state is constructed. Finally, it is revealed that superp...     

Transition prediction of a hypersonic boundary layer over a cone at small angle of attack—with the improvement of e<Superscript><Emphasis Type="Italic">N</Emphasis></Superscript> method

The problem of transition prediction for hypersonic boundary layers over a sharp cone has been studied in this work. The Mach number of the oncoming flow is 6, the cone half-angle is 5°, and the angle of attack is 1°. The conventional e ^N method is used, but the transition location so obtained is obviously incorrect. The reason is that in the conventional method, only the amplifying waves are taken into account, while in fact, for different meridians the decay processes of the disturbances before they begin to grow are different. Based on our own previous work, new interpretation and essential improvement for the e ^N method are proposed. Not only the amplification process but also the decay process is considered. The location, where by linear stability theory, the amplitude of disturbance wave is amplified from its initial small value to 1%, is considered to be the transition location. The new result for transition prediction thus obtained is found to be fairly satisfactory. It is also indicated that for the calculation of base flow, boundary layer equations can be used for a small angle of attack. Its computational cost is much smaller than those for DNS. Supported by the National Natural Science Foundation of China (Grant Nos. 10632050 and 90716007), the Special Foundation for the Authors of National Excellent Doctoral Dissertations (Grant No. 200328), and the Foundation of Liu-Hui Center of Applied Mathematics of Nankai University and Tianjin University     

The <Emphasis Type="Italic">q</Emphasis>-Analogues of Squeezed States and Some Properties

In this paper we shall introduce two q-analogues of the squeezed states in terms of the technique of integration within an ordered product of operators and the properties of the inverses of q-deformed annihilation and creation operators, and some nonclassical properties of the states are examined. Furthermore, we obtain some new completeness relations composed of the bra and ket which are not mutually Hermitian conjugate. PACS numbers: 03.65.-w; 45.50.Ct. Work supported by the National Natural Science Foundation of China under Grant 10574060 and the Natural Science Foundation of Shandong Province of China under Grant Y2004A09.     

Superconductivity at 36 K in gadolinium-arsenide oxides GdO<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>F<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>FeAs

In this paper we report the fabrication and superconducting properties of GdO_1−x F _x FeAs. It was found that when x is equal to 0.17, GdO_0.83F_0.17FeAs is a superconductor with the onset transition temperature T _c^on ≈ 36.6 K. Resistivity anomaly near 130 K was observed for all samples up to x = 0.17, and such a phenomenon is similar to that of LaO_1−x F _x FeAs. Hall coefficient indicates that GdO_1−x F _x FeAs is conducted by electron-like charge carriers. Recommended by Prof. Nie Yuxin, Executive Editor of Science in China Series G-Physics, Mechanics & Astronomy Supported by the National Natural Science Foundation of China (Grant Nos. 10221002/A0402 and 10774170/A0402), the National Basic Research Program of China (973 Program) (Grant Nos. 2006CB601000, 2006CB921107 and 2006CB921802), and the Chinese Academy of Sciences (ITSNEM)     

Quantum secret sharing between <Emphasis Type="Italic">m</Emphasis>-party and <Emphasis Type="Italic">n</Emphasis>-party with six states

A quantum secret sharing scheme between an m-party group and an n-party group is proposed using three conjugate bases. A sequence of single photons, each of which is prepared in one of the six states, is used directly to encode classical information in the quantum secret sharing process. In this scheme, each of all m members in group 1 chooses randomly his/her own secret key individually and independently, and directly encodes his/her respective secret information on the states of single photons via unitary operations, then the last one sends 1/n of the resulting qubits to each member of group 2. By measuring their respective qubits, all members in group 2 share the secret information shared by all members in group 1. It renders impossible a Trojan horse attack with a multi-photon signal, a fake-signal attack with EPR pairs, an attack with single photons, and an attack with invisible photons. We give the upper bounds on the average success probabilities for dishonest agent eavesdropping encryption using the fake-signal attack with any two-particle entangled states. Supported by the National Natural Science Foundation of China (Grant No. 10671054), the Key Project of Science and Technology Research of Education Ministry of China (Grant No. 207011) and the Natural Science Foundation of Hebei Province, China (Grant Nos. 07M006 and F2009000311)     

First-principles calculations on the electronic structure and optical properties of BaSi<Subscript>2</Subscript>

The electronic structure, densities of states and optical properties of the stable orthorhombic BaSi₂ have been calculated using the first-principle density function theory and pseudopotential method. The results show that BaSi₂ is an indirect semiconductor with the band gap of 1.086 eV, the valence bands of BaSi₂ are mainly composed of Si 3p, 3s and Ba 5d, and the conduction bands are mainly composed of Ba 6s, 5d as well as Si 3p. The static dielectric function ɛ ₁(0) is 11.17, the reflectivity n ₀ is 3.35, and the biggest peak of the absorption coefficient is 2.15×10₅ cm⁻¹. Supported by the National Natural Science Foundation of China (Grant Nos. 60566001 and 60766002), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20050657003), the Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Education of China (Grant No. (2005)383), the Specialized Fund of Nomarch for Excellent Talent of Science and Technology of Guizhou Province (Grant No. Z053114), the Scientific and Technological Projects for the Returned Overseas of Guizhou Province (Grant No. (2004)03), and the Top Talent’s Scientific Research Project of Organization Department of Guizhou Province (Grant No. Z053123)     

Factors affecting the superconductivity in the process of depositing Nd1.85Ce0.15CuO4-δ by the pulsed electron deposition technique

On SrTiO₃ single crystal substrate, by using the pulsed electron deposition technique, the high-quality electron doped Nd_1.85Ce_0.15CuO_4−δ superconducting film was successfully fabricated. After careful study on the R-T curves of the obtained samples deposited with different substrate temperatures, thicknesses, annealing methods and pulse frequencies, the effects of them on the superconductivity of the films were found, and the reasons were also analyzed. Additionally, by using the same model of the pulsed laser deposition technique, the relation between the target-to-substrate distance and the deposition pressure was drawn out as a quantitative one. Supported by the Key Project of Zhejiang Provincial Natural Science Foundation (Grant No. Z605131), the ‘100 Talents Project’ of Chinese Academy of Sciences, the Creative Research Group of National Natural Science Foundation of China (Grant No. 60321001) and the National Natural Science Foundation of China (Grant No. 60571029)     

The size effect on transport properties of colossal magnetoresistance materials La<Subscript>0.67</Subscript>Ca<Subscript>0.33</Subscript>MnO<Subscript>3</Subscript>

High quality La_0.67Ca_0.33MnO₃ (LCMO) film was deposited via a novel pulsed electron deposition technique on SrTiO₃(100) single crystal substrate. The micro-bridge with different widths was fabricated by using electron beam lithography (EBL) technique and their transport properties were studied. For the micro-bridges with width of 2 and 1.5 μm, the insulator-to-metal transition temperature (T _P) keeps unchanged compared with the film. For the micro-bridges with width of 1 μm, the T _P shifts towards the lower temperature by 50 K. When the width decreases down to 500 nm, the insulator-to-metal transition disappears. The magnetoresistance behavior of these micro-bridges was studied, and the results show that the low field magnetoresistance (LFMR) decreases and the high field magnetoresistances (HFMR) keep almost unchanged as the width of micro-bridge is reduced. Supported by the Key Project of the Natural Science Foundation of Zhejiang Province of China (Grant No. Z605131), the National Natural Science Foundation of China (Grant No. 60571029), and W. H. Tang was supported by the Creative Research Group of National Natural Science Foundation of China (Grant No. 60321001)     

Remote Preparation of a Two-Particle Entangled State via Two Tripartite <Emphasis Type="Italic">W</Emphasis> Entangled States

We present a scheme for remotely preparing a general two-particle entangled state via two tripartite W entangled states of different amplitudes. In this scheme one sender and two remote receivers are involved. The sender can help either one of the receivers to remotely reconstruct the original state with the aid of the other receiver’s two single-particle orthogonal measurements. It is shown that by means of the method of the positive operator-valued measurement, our remote state preparation scheme can be achieved probabilistically. This project supported by the National Key Basic Research and Development Program of China under Grant No. 2006CB921604 and the National Natural Science Foundation of China under Grant Nos. 60578050 and 10434060.     

Antisite defect types and temporal evolution characteristics of D0<Subscript>22</Subscript>-Ni<Subscript>3</Subscript>V structure: Studied by the microscopic phase field

Microscopic phase field simulation is performed to study antisite defect type and temporal evolution characteristic of D0₂₂-Ni₃V structure in Ni₇₅Al _x V_25−x ternary system. The result demonstrates that two types of antisite defect V_Ni and Ni_V coexist in D0₂₂ structure; however, the amount of Ni_V is far greater than V_Ni; when precipitates transform from D0₂₂ singe phase to two phases mixture of D0₂₂ and L1₂ with enhanced Al:V ratio, the amount of V_Ni has no evident response to the secondary L1₂ phase, while Ni_V exhibits a definitely contrary variation tendency: Ni_V rises without L1₂ structure precipitating from matrix but declines with it; temporal evolution characteristic and temperature dependent antisite defect V_Ni, Ni_V are also studied in this paper: The concentrations of the both defects decline from high antistructure state to equilibrium level with elapsed time but rise with elevated temperature; the ternary alloying element aluminium atom occupies both α and β sublattices of D0₂₂ structure with a strong site preference of substituting α site. Supported by the National Natural Science Foundation of China (Grant Nos. 50671084 and 50875217), the Doctorate Foundation of Northwestern Polytechnical University of China (Grant No. CX200806), the China Postdoctoral Science Foundation Funded Project (Grant No. 20070420218), and the Natural Science Foundation of Shaanxi Province of China     

Online diagnosis of electron excitation temperature in CH<Subscript>4</Subscript>+H<Subscript>2</Subscript> discharge plasma at atmospheric pressure by optical emission spectra

Methane coupling under low temperature plasmas at atmospheric pressure is a green process by use of renewable sources of energy. In this study, CH₄+H₂ discharge plasma was on-line diagnosed by optical emission spectra so as to characterize the discharge system and to do spade work for the optimization of the technical parameters for future commercial production of methane coupling under plasmas. The study was focused on a calculation method for the online diagnosis of the electron excitation temperature in CH₄+H₂ discharge plasma at atmospheric pressure. The diagnostic method is easy, efficient and fairly precise. A serious error in a literature was corrected during the reasoning of its series of equations formerly used to calculate electron temperatures in plasmas. Supported by the National Natural Science Foundation of China (Grant Nos. 29776037 and 10675028) and the Science and Technology Development Foundation of SINOPEC (Grant No. X500005)     

The atomic structure and the properties of ununbium (<Emphasis Type="Italic">Z</Emphasis> = 112) and Mercury (<Emphasis Type="Italic">Z</Emphasis> = 80)

A super heavy element Uub (Z = 112) has been studied theoretically in conjunction with rela-tivistic effects and the effects of electron correlations. The atomic structure and the oscillator strengths of low-lying levels have been calculated, and the ground states have also been determined for the singly and doubly charged ions. The influence of relativity and correlation effects to the atomic properties of such a super heavy element has been investigated in detail. The results have been compared with the properties of an element Hg. Two energy levels at wave numbers 64470 and 94392 are suggested to be of good candidates for experimental observations.