bluuebunny/crossref_metadata_2025 huggingface dataset:
Kα transition probabilities for platinum and uranium ions for possible X-ray biomedical applications1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.
Authors: Nahar Sultana N. , Pradhan Anil K. , Lim Sara
Published: May 2011

Platinum compounds, such as cisplatin and other high-Z materials, are increasingly common in biomedical applications. The absorption and emission of high-energy X-rays can occur via the 1s–2p Kα transitions in ions of heavy elements involving deep inner-shells. Oscillator strengths (f), line strengths (S), and radiative decay rates (A), for the 1s–2p transitions for the nine ionic states from hydrogen-like to fluorine-like, are presented for platinum and uranium. For platinum ions the Kα transitions are found to be in the hard X-ray region, 64–71 keV (0.18–0.17 Å), and for uranium ions they are in the range 94–105 keV (0.12–0.13 Å). Since the number of electrons in each ionic state of the element is different, the number of Kα transitions varies considerably. While there are two 1s–2p transitions (1s 2S1/2–2p [Formula: see text]) in H-like ions, there are 2, 6, 2, 14, 35, 35, and 14 transitions in He-like, Li-like, Be-like, B-like, C-like, N-like, and O-like ions, respectively, for a total of 112 Kα transitions for each element. These include both types of electric dipole (E1) allowed transitions, same-spin multiplicity and intercombination. The former dipole allowed transitions are in general strong; their radiative decay rates are of the order of A ∼ 1016 s–1. However, there are also many weaker transitions. We demonstrate the importance of these Kα transitions, as they appear as resonances in photo-ionization, which is relevant to the enhanced production of Auger electrons for possible radiation diagnostics and therapy.
Spectroscopic analysis and modeling of tungsten EBIT and Z-pinch plasma experiments1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.
Authors: Osborne G.C. , Safronova A.S. , Kantsyrev V.L. , Safronova U.I. , Beiersdorfer P. , Williamson K.M. , Weller M.E. , Shrestha I.
Published: May 2011

Spectral tungsten data taken on an electron beam ion trap (EBIT) at Lawrence Livermore National Laboratory are analyzed between 3 and 8 Å for electron beam energies between 2.5 and 4.1 keV. The advantage of using charge state balancing with the experimental EBIT spectra for the identification of lines is employed and discussed. Theoretical Hebrew University Lawrence Livermore Atomic Code (HULLAC) modeling is then benchmarked against the experimental EBIT results. In particular, Co-, Ni-, Zn-, Cu-, Ga-, and Ge-like transitions were modeled independently using HULLAC to aid in charge state balancing. This model is then compared with Z-pinch plasma data collected on Zebra, the 1.6 MA pulse power generator located in the Nevada Terawatt Facility at the University of Nevada, Reno. The model is used to calculate charge balance and average ionization levels of these experimental plasma results, with particular focus on planar tungsten arrays.
Tungsten spectroscopy at the Livermore electron beam ion trap facility1This review is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.
Authors: Clementson J. , Beiersdorfer P. , Brown G.V. , Gu M.F. , Lundberg H. , Podpaly Y. , Träbert E.
Published: May 2011

The utilization of tungsten spectroscopy for diagnostics of magnetically confined fusion plasmas requires the radiative properties of tungsten ions to be accurately known. At the Lawrence Livermore National Laboratory, a program to gather spectroscopic data on tungsten ions has been initiated with the purpose to study spectral signatures and identify candidate fusion plasma diagnostics. In this paper, an overview of recent results from the Livermore WOLFRAM spectroscopy project is presented, which includes experimental investigations at the EBIT-I and SuperEBIT electron beam ion traps. In particular, the spectra of highly charged M- and L-shell tungsten ions have been studied. These investigations cover energy measurements of n = 2 to n = 2, 3 transitions in Ne-like W64+ through Li-like W71+ ions and soft X-ray measurements of n = 3 to n = 3, 4 transitions in M-shell ions with emphasis on the Ni-like W46+ and Si-like W60+ through Na-like W63+ ions. The measurements are complemented by atomic-structure calculations and spectral modeling using the Flexible Atomic Code (FAC).
Creation, destruction, and transfer of atomic multipole moments by electron scattering: relativistic treatment1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.
Authors: Csanak G. , Fontes C.J. , Kilcrease D.P. , Fursa D.V.
Published: May 2011

We have obtained expressions for the creation, destruction, and transfer of atomic multipole moments by electron scattering under relativistic conditions. More specifically, we have obtained separate expressions for different-level processes (inelastic scattering) and for same-level processes (elastic and inelastic scattering). The cross sections for different-level processes are expressed in terms of inelastic magnetic sublevel cross sections, except for the coherence transfer cross section, which is expressed in terms of an angular integral of a product of inelastic magnetic sublevel amplitudes. The same-level cross sections are expressed in terms of the imaginary part of the elastic forward scattering amplitude and in terms of elastic scattering magnetic sublevel cross sections, except for the coherence transfer cross section, which is expressed in terms of the (complex) forward elastic scattering amplitudes and an angular integral of a product of elastic scattering magnetic sublevel amplitudes. If the collisional model supports the optical theorem, then the same-level cross sections can be rewritten in such a form that they are broken up into two parts: an elastic scattering part and an inelastic scattering part. In carrying out this work, we have used the density matrix formalism of Fano and Blum in combination with the electron scattering formalism of Gell-Mann and Goldberger.
Radiative power losses and opacity calculations in fusion plasmas1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.
Authors: Benredjem D. , Calisti A. , Mondet G. , Pain J.C. , Gilleron F.
Published: May 2011

We present recent results on radiative power losses of carbon and gold ions in fusion plasmas. Our approach is based on a detailed calculation, where the atomic database is provided by the MCDF code. A lineshape code, allowing for NLTE ionic populations, was adapted to the calculation of radiative power loss profiles. Because the calculation time is sometimes prohibitive, an alternative approach based on statistical distributions is proposed. This approach involves the first four moments of the radiative power losses. We have focused our attention on carbon and gold. The first element could be present in the ablator in some inertial confinement schemes. The second element is present in holraums and its X-ray emission contributes to the heating in inertial confinement fusion. Finally, opacity calculations are compared to measured transmission in aluminum ions.
K-shell spectroscopy of Au plasma generated with a short-pulse laser1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.
Authors: Zulick C. , Dollar F. , Chen H. , Falk K. , Gregori G. , Hazi A. , Murphy C.D. , Park J. , Seely J. , Szabo C.I. , Tommasini R. , Shepherd R. , Krushelnick K.
Published: May 2011

The production of X-rays from electron transitions into K-shell vacancies (Kα,β) emission) is a well-known process in atomic physics and has been extensively studied as a plasma diagnostic in low- and mid-Z materials. However, X-ray spectra from near neutral high-Z ions are very complex, and their interpretation requires the use of state-of-the-art atomic calculations. In this experiment, the Titan laser system at Lawrence Livermore National Laboratory was used to deliver an approximately 350 J laser pulse, with a 10 ps duration and a wavelength of 1054 nm, to a gold (Au) target. A transparent bent quartz crystal spectrometer with a hard X-ray energy window, ranging from 17 to 102 keV, was used to measure the emission spectrum. Kα1,α2 and Kβ1,γ1 transitions were observed over a range of target sizes. Additionally, a series of shots were conducted with a pre-ionizing long pulse (3 ns, 1–10 J, 527 nm) on the backside of the target. FLYCHK, an atomic non-LTE code, designed to provide ionization and population distributions, was used to model the experiment. Kα/Kβ ratios were found to be in good agreement with the predicted value for room temperature Au targets.
FIRST-PRINCIPLES HIGH-PRESSURE ELASTIC AND THERMODYNAMIC PROPERTIES OF TANTALUM
Authors: WU JING-HE , ZHAO XIAN-LIN , SONG YOU-LIN , WU GUO-DONG
Published: May 2011

The all-electron full-potential linearized muffin-tin orbital method, by means of quasi-harmonic Debye model, is applied to investigate the elastic constant and thermodynamic properties of body-centered-cubic tantalum (bcc Ta). The calculated elastic constants of bcc Ta at 0 K is consistent with the previous experimental and theoretical results. Our calculations give the correct trends for the pressure dependence of elastic constants. By using the convenient quasi-harmonic Debye model, we refined the thermal equations of state. The thermal expansivity and some other thermal properties agree well with the previous experimental and theoretical results.
HOMOLOGY GROUPS OF TRIVIAL QUANDLES WITH GOOD INVOLUTIONS AND TRIPLE LINKING NUMBERS OF SURFACE-LINKS
Authors: OSHIRO KANAKO
Published: May 2011

The purpose of this paper is to determine the homology groups of trivial quandles with good involutions. We also show that the quandle cocycle invariants of surface-links obtained from trivial quandles with good involutions are equivalent to the triple linking numbers.
CLASSICAL AND VIRTUAL PSEUDODIAGRAM THEORY AND NEW BOUNDS ON UNKNOTTING NUMBERS AND GENUS
Authors: HENRICH A. , MACNAUGHTON N. , NARAYAN S. , PECHENIK O. , TOWNSEND J.
Published: May 2011

A pseudodiagram is a diagram of a knot with some crossing information missing. We review and expand the theory of pseudodiagrams introduced by Hanaki. We then extend this theory to the realm of virtual knots, a generalization of knots. In particular, we analyze the trivializing number of a pseudodiagram, i.e. the minimum number of crossings that must be resolved to produce the unknot. We consider how much crossing information is needed in a virtual pseudodiagram to identify a non-trivial knot, a classical knot, or a non-classical knot. We then apply pseudodiagram theory to develop new upper bounds on unknotting number, virtual unknotting number, and genus.
ELECTRO-WEAK TRANSITIONS OF 4He USING REALISTIC NUCLEAR INTERACTIONS
Authors: HORIUCHI WATARU , SUZUKI YASUYUKI , SATO TORU
Published: May 2011

In this contribution we discuss electro-weak induced transitions involving 4 He . The wave function of the ground state is obtained accurately using an explicitly correlated basis with a realistic nuclear interaction. Four-body final states are expressed in a superposition of many basis functions which contain important configurations for the low-lying transition strength. Resonant and continuum states are treated properly in the complex scaling method. The discussion is mainly focused on the electric dipole strength. Also, we mention those transitions induced by the weak interactions which are important for a neutrino-nucleus reaction.
PURE α-208Pb STATES IN 212Po REVEALED BY THEIR ENHANCED E1 DECAYS: A NOVEL α CLUSTERING
Authors: ASTIER ALAIN , PETKOV PAVEL , PORQUET MARIE-GENEVIÈVE , DELION DORU S. , SCHUCK PETER
Published: May 2011

Excited states in 212 Po have been populated by α transfer using the 208 Pb (18 O ,14 C ) reaction and studied with the Euroball γ multidetector array. Very enhanced E1 transitions have been revealed by very short lifetimes measured by the DSAM method, found in the [0.1-1.4] ps range. The emitting states, which have non-natural parity values, are the fingerprints of the "α-208 Pb " structure present in 212 Po . They are in the same excitation-energy range as the states issued from shell-model configurations.
PROBING THE 12C - 12C AND 12C - 16O MOLECULAR STATES BY RADIATIVE CAPTURE REACTIONS: PRESENT STATUS AND FUTURE
Authors:   the PARIS collaboration, LEBHERTZ D. , COURTIN S. , HAAS F. , JENKINS D. G. , CIEMALA M. , GOASDUFF A. , HUTCHEON D. A. , LABICHE M. , MICHALON A. , ROBERTS O. , SALSAC M.-D. , STEZOWSKI O.
Published: May 2011

Complete γ-decay in the 12 C (12 C ,γ)24 Mg and 12 C (16 O ,γ)28 Si reactions has been measured at energies close to the Coulomb Barrier using the DRAGON spectrometer and its associated BGO γ-array at the TRIUMF facility. The experimental data show an important feeding of doorway states around 10-11 MeV in both reactions. Comparisons with simulations allow to extract the full capture cross section and the main spin involved in the process. Different models are confronted to the results : completely statistical, semi-statistical with an unique entrance spin and cluster. The resolution of the BGO enables to eliminate a fully statistical scenario but is not enough to disentangle the two remaining scenarii. It is shown that the future PARIS array composed of the recently developed LaBr 3 scintillators will have capabilities to distinguish between these two scenarii.
MOMENTUM DISTRIBUTIONS FROM THREE-BODY DECAYING 9Be AND 9B RESONANCES
Authors: ÁLVAREZ-RODRÍGUEZ R. , JENSEN A. S. , FEDOROV D. V. , GARRIDO E.
Published: May 2011

The complex-rotated hyperspherical adiabatic method is used to study the decay of low-lying 9 Be and 9 B resonances into α, α and n or p. We consider six low-lying resonances of 9 Be (1/2±, 3/2± and 5/2±) and one resonance of 9 B (5/2-) to compare with. The properties of the resonances at large distances are decisive for the momentum distributions of the three decaying fragments. Systematic detailed energy correlations of Dalitz plots are presented.
BRUECKNER-AMD STUDY OF LIGHT NUCLEI
Authors: YAMAMOTO YUHEI , TOGASHI TOMOAKI , KATŌ KIYOSHI
Published: May 2011

We applied the Brueckner theory to the Antisymmetrized Molecular Dynamics (AMD), and show the reliability of the AMD calculations based on realistic nuclear interactions. Focusing our interest on a structure dependence of the tensor force, we investigate the α-α clusterization of 8 Be .
ALPHA CLUSTERING AND CONDENSATION IN NUCLEI
Authors: FUNAKI Y. , YAMADA T. , HORIUCHI H. , RÖPKE G. , SCHUCK P. , TOHSAKI A.
Published: May 2011

Low density states near the 3α and 4α breakup threshold in 12 C and 16 O , respectively, are discussed in terms of the α-particle condensation. Calculations are performed in OCM (Orthogonality Condition Model) and THSR (Tohsaki-Horiuchi-Schuck-Röpke) approaches. The [Formula: see text] state in 12 C and the [Formula: see text] state in 16 O are shown to have dilute density structures and give strong enhancement of the occupation of the S-state c.o.m. orbital of the α-particles. The possibility of the existence of α-particle condensed states in heavier nα nuclei is also discussed.
LIGHT CLUSTERS IN NUCLEAR MATTER
Authors: RÖPKE GERD
Published: May 2011

Within a quantum statistical approach, a in-medium Schrödinger equation is derived for a few-nucleon system embedded in nuclear matter. Medium modifications of the cluster quasiparticles are described by self-energy and Pauli blocking effects. Benchmarks such as the nuclear statistical equilibrium, virial expansion and the relativistic mean field approximation are considered. An interesting effect is the formation of a four- or two-nucleon quantum condensate, showing the crossover from Cooper pairing to Bose-Einstein condensation. The resulting thermodynamic properties are of interest for heavy-ion collisions and astrophysical applications. Quantum condensates and the Mott effect are also of relevance for the structure of finite nuclei, specially dilute excited states like the Hoyle state of 12 C .
NEAR BARRIER REACTIONS INDUCED BY WEAKLY BOUND CLUSTER NUCLEI
Authors: PENIONZHKEVICH YU. E.
Published: May 2011

Experimental excitation functions are presented for complete fusion and transfer reactions in the interaction of 6 He and 6,8,9 Li with 206 Pb , 209 Bi , and nat Pt targets. The data on fusion in the 6 He -induced reactions at energies close to the Coulomb barrier differ from predictions within the framework of the statistical model for compound nucleus decay. For these exit channels a strong enhancement has been observed. Enhancement of the cross section for neutron transfer (with the 6 He and 8,9 Li beams) and deuteron transfer (with the 6 Li beam) reactions is observed at deep sub-barrier energies. The results are discussed from the viewpoint of how the nuclear cluster structure influences the probability of interaction at near-barrier energies.
RESONANCES EXCITED BY THE 9Be(6Li,d)13C REACTION
Authors: BORELLO-LEWIN T. , HORODYNSKI-MATSUSHIGUE L.B. , DUARTE J.L.M. , RODRIGUES C.L. , SOUZA M.A. , MIYAKE H. , RODRIGUES M.R.D. , CUNSOLO A. , CAPPUZZELLO F. , UKITA G.M.
Published: May 2011

Alpha resonant states in 13 C up to 15 MeV were excited by the 9 Be (6 Li , d )13 C reaction. The data were taken at a bombarding energy of 25.5 MeV employing the São Paulo-Pelletron-Enge Split Pole facility and the nuclear emulsion technique. The resolution of 50 keV allowed for the separation of the resonant contributions to the known 7/2- and (5/2-) states near the 9 Be + α threshold both associated with an L = 4 transfer. Several narrow alpha resonant states not previously measured were detected, in particular the one at the 3α + n threshold populated by an L = 2 transfer, revealing a 9Be + α component for the 1/2- cluster state candidate at this threshold.
Li-α CLUSTER STATES IN 12B USING 8Li + 4He INVERSE KINEMATICS ELASTIC SCATTERING
Authors: TORRESI D. , LATTUADA M. , MUSUMARRA A. , PELLEGRITI M.G. , ROVITUSO M. , SCALIA G. , STRANO E. , COSENTINO L. , DI PIETRO A. , FIGUERA P. , MAIOLINO C. , SANTONOCITO D. , DUCOIN C. , PAPA M. , FISICHELLA M. , LONNROTH T. , SCUDERI V. , ZADRO M.
Published: May 2011

The 8Li elastic scattering on a 4He gas target was studied by means of the Inverse Kinematic Thick Target scattering method (TTIK) in order to investigate cluster configurations in excited states of 12 B . A 8 Li beam, at Ec.m. = 10.2 MeV , was provided by the EXCYT radioactive beam facility at Catania. The beam, while passing through the helium thick target decreases its energy, thus exploring the 8 Li -α center-of-mass energy range 2.7 MeV ≤ECM ≤9.6 MeV . Four Δ E - E silicon detector telescopes were used to detect the recoiling alpha particles. The time interval between the 8 Li passing through a micro-channel plate foil, placed at the entrance of the chamber, and the detection of the α particles by the Δ E detectors was also measured. The time measurement allows to disentangle elastic from reactions events, otherwise impossible from energy measurements. This can be considered as an improvement of the TTIK method. In this paper the used experimental technique and the obtained preliminary results will be presented.
ON THE EMISSION OF HEAVY CLUSTERS FROM MEDIUM MASS COMPOUND NUCLEUS
Authors:   for the E475S collaboration, ADEMARD G. , WIELECZKO J.P. , BONNET E. , CHBIHI A. , FRANKLAND J.D
Published: May 2011

Fragments with atomic number 6≤ Z ≤28 were measured in singles and in coincidence with emitted light charged particles in the 78 Kr +40 Ca reactions at 5.5 AMeV incident energy by means of the 4π-INDRA array at GANIL. Kinematical features of the fragments are compatible with a binary fission from compound nucleus. The cross-sections σZ indicate the coexistence of macroscopic behaviour and structure effects. Fragment-particle coincidences show that fragments with Z ≤12 are excited below the separation energies of light particles.
OBSERVATION OF HEAVY CLUSTER STRUCTURE OF 18O BY INCLUSIVE MEASUREMENT OF INTERMEDIATE MASS FRAGMENT EMITTED IN 18O+12C REACTION AT 80 MeV
Authors: BASU C. , ADHIKARI S. , MITRA A.K. , RAY S. , PANDIT S. , KUMAR SURESH , CHATTERJEE A.
Published: May 2011

An inclusive measurement of the Intermediate Mass Fragments(IMF) with Z =3,4,5 emitted from 18 O +12 C reaction at 80 MeV has been done. Reaction model analysis show that at such low energies IMF s are emitted primarily from projectile breakup. This indicates possible heavy cluster configurations of the 18 O nucleus.
LIGHT CLUSTERS EMISSION IN NUCLEAR REACTIONS AT 25 MeV/NUCLEON WITH DIFFERENT N/Z OF ENTRANCE CHANNELS
Authors: LOMBARDO I. , AGODI C. , ALBA R. , AMORINI F. , ANZALONE A. , AUDITORE L. , BERCEANU I. , CARDELLA G. , CAVALLARO S. , CHATTERJEE M.B. , DEFILIPPO E. , DIPIETRO A. , FIGUERA P. , GERACI E. , GIULIANI G. , GRASSI L. , GRZESZCZUK A. , HAN J. , LA GUIDARA E. , LANZALONE G. , LE NEINDRE N. , LORIA D. , MAIOLINO C. , PAGANO A. , PAPA M. , PIRRONE S. , POLITI G. , POP A. , PORTO F. , RIZZO F. , RUSSOTTO P. , SANTONOCITO D. , TRIFIRÒ A. , VERDE G. , VIGILANTE M.
Published: May 2011

We discuss results on the emission of light clusters in nuclear reactions 40 Ca + 40,48 Ca ,46 Ti at 25 MeV/nucleon. They were detected and identified in mass and charge by means of the CHIMERA 4π array. Inclusive emission at forward angles shows that isotopic yields of Li and Be nuclei are related to the N/Z values of entrance channels. Moreover, structure effects and even-odd staggering in charge distributions of intermediate mass fragments emitted at forward angles will be shown. In agreement with previous experimental findings, odd-even effects are clearly visible in N ≈ Z systems, while are less pronounced in the neutron rich collision 40 Ca +48 Ca . These experimental findings are compared to preliminary data obtained in 40 Ca +48 Ca . collision at 25 MeV/nucleon.
EVALUATE DISSIMILARITY OF SAMPLES IN FEATURE SPACE FOR IMPROVING KPCA
Authors: YONG XU , ZHANG DAVID , YANG JIAN , ZHONG JIN , YANG JINGYU
Published: May 2011

Since in the feature space the eigenvector is a linear combination of all the samples from the training sample set, the computational efficiency of KPCA-based feature extraction falls as the training sample set grows. In this paper, we propose a novel KPCA-based feature extraction method that assumes that an eigenvector can be expressed approximately as a linear combination of a subset of the training sample set ("nodes"). The new method selects maximally dissimilar samples as nodes. This allows the eigenvector to contain the maximum amount of information of the training sample set. By using the distance metric of training samples in the feature space to evaluate their dissimilarity, we devised a very simple and quite efficient algorithm to identify the nodes and to produce the sparse KPCA. The experimental result shows that the proposed method also obtains a high classification accuracy.
A FUZZY AHP MULTI-CRITERIA DECISION-MAKING APPROACH APPLIED TO COMBINED COOLING, HEATING, AND POWER PRODUCTION SYSTEMS
Authors: NIETO-MOROTE ANA , RUZ-VILA FRANCISCO
Published: May 2011

Most of the real-world multicriteria decision-making (MCDM) problems contain a mixture of quantitative and qualitative criteria; therefore quantitative MCDM methods are inadequate for handling this type of decision problems. In this paper, a MCDM method based on the Fuzzy Sets Theory and on the Analytic Hierarchy Process (AHP) is proposed. This method incorporates a number of perspectives on how to approach the fuzzy MCDM problem, as follows: (1) combining quantitative and qualitative criteria; (2) expressing criteria pair-wise comparison in linguistic terms and performance of the alternative on each criterion in linguistic terms or exact values when criterion is qualitative or quantitative, respectively; (3) converting all the assessments into trapezoidal fuzzy numbers; (4) using the difference minimization method to calculate the local weight of criteria, employing the algebraic operations of fuzzy numbers based on the concept of α-cuts; (5) calculating the global weight of criteria and the global performance of each alternative using geometric mean and the weighted sum, respectively; (6) using the centroid method to rank the alternatives. Finally, an illustrative example on evaluation of several combined cooling, heat, and power production systems is used to demonstrate the effectiveness of the proposed methodology.
CROSS-MARKET FINANCIAL RISK ANALYSIS: AN AGENT-BASED COMPUTATIONAL FINANCE
Authors: XIONG XIONG , WEN MEI , ZHANG WEI , ZHANG YONG JIE
Published: May 2011

Using the method of agent-based computational finance, this paper designs ten experiments to examine the impacts of the index futures market, typical investment strategies, and different trading mechanisms on the volatility of the Chinese stock market, taking into account the behavior of investors. We have the following results. First, the volatility of the stock market decreases with the index future market and cross-market arbitrageurs. Second, different investment strategies have different effects on stock market volatility. In many cases, both market-imitating and stop-loss strategies can increase stock market volatility. Third, the mechanism of price limits for the index futures market can help to stabilize the fluctuation of the stock market.
THE INFLUENCE OF DZYALOSHINSKII–MORIYA ANISOTROPIC ANTISYMMETRIC INTERACTION ON ENTANGLEMENT IN A THREE-QUBIT ISING MODEL WITH INTRINSIC DECOHERENCE
Authors: GAO DAN , ZHAO ZHEN-SHUANG , WANG HONG-FU , ZHANG SHOU , YEON KYU-HWANG
Published: May 2011

We investigate the effect of the Dzyaloshinskii–Moriya anisotropic antisymmetric interaction on entanglement in a three-qubit Ising model with intrinsic decoherence. The entanglement of the nearest and the next-nearest neighbor qubit is calculated. The results show that, taking into account the intrinsic decoherence, when the qubits are initially in the maximal entangled state, the concurrence of the system decreases with the increasing Dzyaloshinskii–Moriya interaction following the evolution of the time t. When the qubits are initially in the disentangled state, the destructive effect of intrinsic decoherence on entanglement can be moderated by the Dzyaloshinskii–Moriya interaction, the concurrence increases with the increasing Dzyaloshinskii–Moriya interaction following the evolution of the time t.
MULTIPARTY CONTROLLED QUANTUM SECURE DIRECT COMMUNICATION WITH PHASE ENCRYPTION
Authors: WANG TIAN-YIN , WEN QIAO-YAN , ZHU FU-CHEN
Published: May 2011

We present a new multiparty controlled quantum secure direct communication protocol with phase encryption, in which the sender's secret message can only be recovered by the receiver under the permission of all the controllers. The security of this scheme is based on the basic principles of quantum mechanics and the secret order of encoding photons.
QUATERNARY CONSTRUCTION OF QUANTUM CODES FROM CYCLIC CODES OVER $\mathbb{F}_4 + u\mathbb{F}_4$
Authors: KAI XIAOSHAN , ZHU SHIXIN
Published: May 2011

We give a construction for quantum codes from linear and cyclic codes over [Formula: see text]. We derive Hermitian self-orthogonal codes over [Formula: see text] as Gray images of linear and cyclic codes over [Formula: see text]. In particular, we use two binary codes associated with a cyclic code over [Formula: see text] of odd length to determine the parameters of the corresponding quantum code.
THE VIABILITY OF INFORMAL MICROENTERPRISE IN SOUTH AFRICA
Authors: WOODWARD DOUGLAS , ROLFE ROBERT , LIGTHELM ANDRÉ , GUIMARÃES PAULO
Published: May 2011

This paper analyzes entrepreneurs in South Africa's informal sector. The aim is to determine the extent to which African informal retail trade spawns viable enterprises. To assess the prospects for South Africa's informal retail sector, we obtained questionnaires from owners of small-scale establishments in a random sample taken throughout the country in 2007. Owner's income and sales data provided a basis for investigating viability. Regression analysis tests hypotheses identified as crucial to higher income and sales, including startup capital, size, male/female ownership, business training and the proximity to shopping centers. Also tested is the influence of urbanization externalities on sales and owner's income. Initial capital and positive urban externalities have a strong influence on the ability to generate a sustainable livelihood for informal entrepreneurs. After controlling for startup capital, location and other factors, it appears women entrepreneurs face distinct difficulties in generating a viable income through informal retail trade.
WOMEN ENTREPRENEURSHIP IN WEST AFRICA: THE COWPEA STREET FOOD SECTOR IN NIGER AND GHANA
Authors: OTOO MIRIAM , FULTON JOAN , IBRO GERMAINE , LOWENBERG-DEBOER JAMES
Published: May 2011

Women entrepreneurship in the informal sector, such as street food vending, is important for poverty alleviation in West Africa. The street food sector provides employment for women and inexpensive and nutritious food for the urban poor. In this paper, we determine the importance of the cowpea street food sector, evaluate the determinants of successful enterprises and ascertain the impact of economic, cultural, religious and geographic differentials between enterprises in Niamey, Niger and Kumasi, Ghana. Data were collected through in-person interviews with 114 and 122 women street food entrepreneurs in both countries in 2009. Results revealed that women entrepreneurs engaged in the cowpea street food sector can earn incomes 4 times and 16 times higher than the minimum legal wage in Niamey and Kumasi, respectively. Incomes earned from these entrepreneurial activities contribute directly to health, education and needs of their families. OLS regression results indicate that lack of financial resources, stable business locations and religious beliefs are important entrepreneurial success factors. Cross-country comparisons revealed enterprises in Kumasi are larger and more successful than those in Niamey.
INSTITUTIONAL AND ECONOMIC FOUNDATIONS OF ENTREPRENEURSHIP IN AFRICA: AN OVERVIEW
Authors: KSHETRI NIR
Published: May 2011

Africa is arguably the richest continent in terms of minerals and natural resources. Prior research has also shown that Africa has an abundance of entrepreneurs who possess the ability to identify business opportunities and exploit them. However, the continent's entrepreneurial performance has been weak. Our goal in this paper is modest and is simply aimed at identifying and synthesizing the available evidence on economic and institutional factors affecting entrepreneurship in Africa. This paper also reviews various mechanisms by which foreign businesses are exploiting Africa for resources and market and examines Western response to the low level of entrepreneurial activities in Africa. Finally, this paper provides case studies of some successful entrepreneurial activities in the continent. The cases indicate that successful businesses do not necessarily need to depend on natural resources.
Substrate Dependence of Structural and Transport Properties in FeSe0.5Te0.5Thin Films
Authors: Hanawa Masafumi , Ichinose Ataru , Komiya Seiki , Tsukada Ichiro , Akiike Takanori , Imai Yoshinori , Hikage Tatsuo , Kawaguchi Takahiko , Ikuta Hiroshi , Maeda Atsutaka
Published: May 2011

In order to clarify the best condition for the growth of iron chalcogenide superconductor thin films, we investigated the effect of the substrate on the transport and structural properties of films. Thin films of FeSe0.5Te0.5grown by pulsed laser deposition were characterized by DC electrical resistivity, Hall effect, X-ray diffraction measurements, and transmission electron microscopy (TEM) observation. Thec-axis length of the FeSe0.5Te0.5thin films revealed a non-systematic change with the cell constants of the substrates. In the films with poor or no superconductivity, we found the occurrence of oxygen penetration to the film and the formation of amorphous layer between the film and the substrate. The origin of the oxygen penetration and the amorphous layer was the chemical properties of substrate. From the chemical viewpoint, LaAlO3and MgO substrates were confirmed to be appropriate to grow FeSe0.5Te0.5films.
Deflections of Magnetic Actuator under Different Directions of External Magnetic Field
Authors: Hsieh Yi-Ping , Li Yun-Jui , Wei Zung-Hang , Chen Wei-Yuan , Chang Jung-Shao , Shiao Hong-Ren , Huang Chen-Chi , Hung Hui-Chun , Lai Mei-Feng
Published: May 2011

A magnetic actuator consisting of a 70×0.525×1 µm3 silicon oxide microcantilever and a 70×5×1 µm3 silicon oxide plate deposited on a 50×1×0.09 µm3 ferromagnetic thin film is successfully fabricated using electron beam lithography and electron beam evaporation, and placed in various magnetic fields to observe its flexure. The magnetic actuator is bent using a magnetic torque produced by a ferromagnetic thin film under an external magnetic field owing to the fabrication of a highly sensitive microcantilever and the design of a high magnetic shape anisotropy. In this study, the magnetic actuator is placed in three magnetic field directions to investigate its diversity of deflections; the angles between the easy axis of the ferromagnetic thin film and the direction of the external magnetic field are 90, 80, and 45°.
Implications of the Differential Equations of the X-ray Free-Electron Laser
Authors: Lee Tae-Yeon
Published: May 2011

Differential equations governing the X-ray free-electron laser are complicated and it is not straightforward to see all the information they have other than the fitting formula for the radiation power gain. Using the equations and the fitting formula but not solving the equations completely, some useful information is obtained including the radiation beam size and the saturation value of the bunching parameter.
Mechanism Verification of Electrochemical Migration of Fine Cu Wiring
Authors: Komatsu Daiki , Takahashi Nobuya , Furutani Toshiki , Bhandari Ramesh Kumar , Sato Kenji , Jinbo Naoyuki , Kariya Takashi
Published: May 2011

The mechanisms of electrochemical migration and consequent insulation failure in fine-pitch Cu wiring (line/space = 3 µm/3 µm) are investigated. A model in which the migration takes place in the presence of water in a phenol-based resin–resin interface between biased Cu traces is proposed. Replacing the bottom resin layer by a SiN layer is found to be an effective method of considerably enhancing the leakage characteristics.
Tribological, Thermal, and Kinetic Characterization of 300-mm Copper Chemical Mechanical Planarization Process
Authors: Jiao Yubo , Sampurno Yasa Adi , Zhuang Yun , Wei Xiaomin , Meled Anand , Philipossian Ara
Published: May 2011

In this study, the tribological, thermal, and kinetic attributes of 300-mm copper chemical mechanical planarization were characterized for two different pads. The coefficient of friction (COF) ranged from 0.39 to 0.59 for the D100 pad, indicating that boundary lubrication was the dominant tribological mechanism. In comparison, COF decreased sharply from 0.55 to 0.03 for the IC1000 pad, indicating that the tribological mechanism transitioned rapidly from boundary lubrication to partial lubrication. Consequently, the D100 pad exhibited higher pad temperatures and removal rates than the IC1000 pad. A two-step modified Langmuir–Hinshelwood model was used to simulate copper removal rates as well as chemical and mechanical rate constants. The simulated copper removal rates agreed very well with experimental data and the model successfully captured the non-Prestonian behavior. The simulated chemical rate to mechanical rate constant ratios indicated that the IC1000 pad generally produced a more mechanically controlled removal mechanism than the D100 pad.
Disappearance of Barrier Metal during Cu Chemical Mechanical Planarization Processing and Its Mechanism
Authors: Asano Hiroshi , Yasui Akihito , Hirano Tatsuhiko , Tamai Kazusei , Morinaga Hitoshi
Published: May 2011

The bald disappearance of barrier metal had been observed on the wafer after Cu chemical mechanical planarization (CMP) processing. It was speculated that this phenomenon occurs because the excessively oxidized Ta by electrochemical reaction with Cu ion was removed more easily than the normal Ta oxide around it. The inhibition of the electrochemical reaction is necessary to solve this phenomenon.
Diffusion Resistance of Low Temperature Chemical Vapor Deposition Dielectrics for Multiple Through Silicon Vias on Bumpless Wafer-on-Wafer Technology
Authors: Kitada Hideki , Maeda Nobuhide , Fujimoto Koji , Mizushima Yoriko , Nakata Yoshihiro , Nakamura Tomoji , Ohba Takayuki
Published: May 2011

Diffusion behavior of Cu in Cu through-silicon-vias (TSVs) fabricated using low-temperature plasma enhanced chemical vapor deposition (LT-PECVD) has been evaluated. Silicon oxynitride (SiON) barrier films were formed by LT-PECVD at 150 °C. Cu diffusion rate was found to increase with decreasing film density. The critical density and thickness for prevention of Cu diffusion into Si substrate have been estimated. In case of a film with density >60% of the bulk value and/or thickness >100 nm, no change of electrical resistance for stacked wafers containing TSVs was observed after 1000 cycles of thermal stress. According to above results, SiON film formed at 150 °C can be used for the TSV process without any degradation of electrical characteristics and reliability, enabling a reduction in total process temperature in the wafer-on-wafer technology.
Mechanism of “Controlled Atomic Defects”: Extension to the Ternary Systems
Authors: Rogacheva Elena
Published: May 2011

The method of “controlled atomic defects” realized by changing the alloy composition along definite sections in the Gibbs triangle is applied to ternary phases of two types: ternary compounds and solid solutions based on binary compounds. The overview of extensive experimental material, which we obtained when studying I–III–VI2 ternary phases and IV–X–VI phases based on IV–VI binary compounds is given. The controlled introduction of non-stoichiometric and impurity defects of different types into I–III–VI2 and IV–VI compounds was realized using the “controlled atomic defects” method. It was shown that there is a distinct correlation between the composition, type and concentration of impurity and non-stoichiometric defects, on the one side, and the crystal structure and physical properties, on the other side. The results obtained prove the fruitfulness of using the “controlled atomic defects” method for the development of physical foundations of controlling properties of complex semiconductor phases.
Growth of IrOx–SnOx Films Deposited by Reactive Sputtering
Authors: Harada Shun , Yoshino Kenji , Fukudome Syuji , Kawano Yoshihiko , Sei Fumihiro
Published: May 2011

IrO
x
–SnO
x
thin films were deposited on a glass substrate by reactive sputtering using two types of SnO2 and Ir targets between room temperature (RT) and 200 °C. The X-ray diffraction pattern indicates crystallization at 100 °C, and identifies IrO
x
–SnO
x
thin films as tetragonal rutile type structures. The IrO
x
–SnO
x
thin films also exhibit low average transmittance and resistivity at 100 °C.
Dielectric Anomaly and Conductivity at Ferroelectric Phase Transition in TlInS2 Doped with Different Impurities
Authors: Alekperov Oktay , Nadjafov Arzu
Published: May 2011

The low-frequency dielectric function and conductivity at ferroelectric phase transition have been analyzed in monoclinic TlInS2 crystals doped with different impurities. Complementary, room-temperature optical absorption and photoconductivity have been examined to identify shallow and deep energy levels caused by the introduced impurities. It is found that only shallow impurities broaden and shift dielectric anomaly towards lower temperatures. Contrary to our expectation, the dark conductivity at the temperature of the dielectric anomaly is maximum rather than minimum. The dielectric breakdown of the shallow impurities is proposed to be responsible for the observed behavior of the dark conductivity in monoclinic TlInS2.
Photoinduced Current Transient Spectroscopy of TlInS2 Layered Crystals Doped with Er, B, and Tb Impurities
Authors: Seyidov MirHasan Yu. , Suleymanov Rauf A. , Odrinsky Andrey P. , Nadjafov Arzu I. , Mammadov Tofig G. , Samadli Elnure G.
Published: May 2011

Photoinduced current transient spectroscopy (PICTS) has been utilized to study electrically active defects in TlInS2 single crystals doped with Er, B, and Tb. Eight traps with activation energies lying in between 0.21 to 0.55 eV have been detected. The origin of these traps is discussed.
Synchrotron Radiation Diffraction Study of YbInCu4
Authors: Utsumi Yuki , Sato Hitoshi , Moriyoshi Chikako , Kuroiwa Yoshihiro , Namatame Hirofumi , Taniguchi Masaki , Hiraoka Koichi , Kojima Kenichi , Sugimoto Kunihisa
Published: May 2011

The structural change of an YbInCu4 single crystal has been investigated associated with the first-order valence-transition at T
V = 42 K using synchrotron radiation diffraction. The Yb–Cu and In–Cu interatomic distances abruptly increase below T
V, following the lattice expansion with no change in the C15b-type crystal structure. We find that the distance between Cu ions forming the Cu4 cluster in the crystal is almost unchanged across the valence transition. No abrupt change in the thermal rotational motion of the Cu4 cluster is observed at T
V.
Local Structure around Mn Atoms in IV–VI Ferromagnetic Semiconductor Ge0.6Mn0.4Te Investigated by X-ray Fluorescence Holography
Authors: Happo Naohisa , Takehara Yuki , Fujiwara Makoto , Tanaka Koichi , Senba Shinya , Hosokawa Shinya , Hayashi Kouichi , Hu Wen , Suzuki Motohiro , Asada Hironori
Published: May 2011

The local atomic structure around Mn atoms in Ge1-x
Mn
x
Te thin-film single crystal has been investigated by X-ray fluorescence holography (XFH) at room temperature. The obtained atomic image suggests that the Mn atoms replace the Ge atoms in the host GeTe, and the Mn position is stable in the exact positions of the anion fcc sublattice. The XFH result also suggests the fluctuation of the Ge positions or the cation vacancies.
Comparison of Optical Parameters of Ge–As(Sb)–Se(Te) Glassy Films
Authors: Mammadov Eldar , Shim Yong-Gu , Sakamoto Junichi , Wakita Kazuki , Mamedov Nazim , Uchiki Hisao
Published: May 2011

We compare optical parameters of Ge2As(Sb)2Se(Te)
x
(x = 5, 7) glassy films. Optical gap obtained from transmission and reflection measurements decreases in the sequence Ge–As–Se → Ge–Sb–Se → Ge–As–Te → Ge–Sb–Te similarly to decreasing glass-forming ability of bulk systems. We have found from spectroscopic ellipsometry measurements that spectral dependence of imaginary part of the dielectric function shifts to lower energies in the same sequence. This indicates to strong correlation between structural arrangement of atoms in these ternaries and their electronic properties. Ge2Sb2Se5 crystallizes upon thermal annealing with accompanying change in reflectivity. No change in the structure of Ge2As2Se5 is found after annealing.
Optical and Structural Properties of Zn–Cd–Mn–Se Double Quantum Well Systems
Authors: Matsumoto Takashi , Ohmori Kenta , Kodama Kazuki , Hishikawa Masao , Fukasawa Sakyo , Iwasaki Fumiaki , Muranaka Tsutomu , Nabetani Yoichi
Published: May 2011

Double quantum well (DQW) structures consisting of a ZnCdSe well and a ZnCdMnSe well separated by a ZnSe barrier are grown with molecular beam epitaxy (MBE). The DQW structures are characterized by using X-ray diffraction measurement and simulation. Thickness of each well layer is designed so that the lowest energy level of ZnCdMnSe well is close to the excited level of the ZnCdSe well. Optical properties of the DQWs are studied with photoluminescence (PL) and reflection spectra in external magnetic fields up to 8 T in the Faraday geometry. Exciton transfer from ZnCdMnSe well to ZnCdSe well is observed in magneto PL with energy selective photoexcitation. Exciton energies in ground and excited states are estimated from PL excitation spectra and reflection spectra.
High-Pressure Studies for Iron-Based Superconductors
Authors: Takahashi Hiroki , Takahashi Hiroyuki , Tomita Takahiro , Okada Hironari , Mizuguchi Yoshikazu , Takano Yoshihiko , Matsuishi Satoru , Hirano Masahiro , Hosono Hideo
Published: May 2011

Electrical and magnetic measurements for 1111 type Ca(Fe1-x
Co
x
)AsF and 11 type Fe(Se1-x
Te
x
) have been performed under high pressure. Superconductivity appeared with Co substitution for Ca(Fe1-x
Co
x
)AsF. For superconducting Ca(Fe1-x
Co
x
)AsF, pressure does not enhance the superconductivity so much. Disorder induced by the Co substitution in the FeAs superconducting layer is considered to be related to the pressure dependence of T
c. Pressure-induced superconductivity was observed for x = 0.0 and 0.05. For Fe(Se1-x
Te
x
), T
c exhibits the maximum value at x = 0.5 and decreases with increasing Te concentration. The enhancement of T
c with pressure was suppressed by increasing Te concentration for Fe(Se1-x
Te
x
) (x ≧0.5). For non-superconducting FeTe, pressure-induced superconductivity was not detected under high pressure up to 19 GPa.
Anomalies in Transport and Superconducting Properties of Ba1-xKxFe2As2 Single Crystals
Authors: Zverev Vladimir N. , Korobenko Alexey V. , Sun Guoli L. , Sun Dunlu L. , Lin Chengtian T. , Boris Alexander V.
Published: May 2011

The transport and superconducting properties of Ba1-x
K
x
Fe2As2 single crystals were studied. Both in-plane and out-of-plane resistivity were measured by Montgomery method. The in-plain resistivity temperature dependence was found to be nonlinear with the tendency to saturate at high temperature. We have found that the resistivity anisotropy is almost independent of temperature and lies in the range 10–40 for the studied samples. We explain this result by the extrinsic nature of high out-of-plane resistivity, which may be due to the presence of flat defects along Fe–As layers. This statement is supported by comparatively small effective mass anisotropy, obtained from the upper critical field measurements.
The Role of Electronic Subsystem in the Negative Thermal Expansion of Ferroelectric–Semiconductor TlGaSe2
Authors: Mammadov Tofig G. , Abdullayev Nadir A. , Seyidov MirHasan Yu. , Suleymanov Rauf A. , Yakar Emin
Published: May 2011

Effect of illumination and external electric field on thermal expansion of TlGaSe2 crystals has been investigated. Strong transformation of negative linear expansion coefficient has been observed. It is supposed that two main mechanisms are responsible for observed effects: formation of electret state and reverse piezoelectric effect. The electronic nature of negative linear expansion of TlGaSe2 crystals has been proved for the first time.
Charged Defects as an Origin of the Memory Effect in Incommensurate Phase of TlInS2 Ferroelectric–Semiconductors
Authors: Seyidov MirHasan Yu. , Suleymanov Rauf A. , Mammadov Tofig G. , Fedotov Aleksandr K. , Babayev Sardar S. , Sharifov Galib M.
Published: May 2011

The effects of annealing within the incommensurate phase and doping with the lanthanum impurity on the dielectric function ε of the TlInS2 single crystals have been investigated. It is shown that illumination and application of external electric field transform the ε(T) dependences for both the annealed and doped samples in the same manner. The inference is made that the correlation between observed effects is conditioned by the internal electric fields induced either by activation (polarization) of native defects during the annealing procedure or after the doping the crystals with active La centers.