Cation mono- and co-doped anatase TiO2_2 nanotubes: An {\em ab initio} investigation of electronic and optical properties

The structural, electronic, and optical properties of metal (Si, Ge, Sn, and Pb) mono- and co-doped anatase TiO$_{2}$ nanotubes are investigated, in order to elucidate their potential for photocatalytic applications. It is found that Si doped TiO$_{2}$ nanotubes are more stable than those doped with Ge, Sn, or Pb. All dopants lower the band gap, except the (Ge, Sn) co-doped structure, the decrease depending on the concentration and the type of dopant. Correspondingly, a redshift in the optical properties for all kinds of dopings is obtained. Even though a Pb mono- and co-doped TiO$_{2}$ nanotube has the lowest band gap, these systems are not suitable for water splitting, due to the location of the conduction band edges, in contrast to Si, Ge, and Sn mono-doped TiO$_{2}$ nanotubes. On the other hand, co-doping of TiO$_{2}$ does not improve its photocatalytic properties. Our findings are consistent with recent experiments which show an enhancement of light absorption for Si and Sn doped TiO$_{2}$ nanotubes.Comment: revised and updated, 23 pages (preprint style), 7 figures, 5 table

Application of SRAP in the genetic diversity of Tricholoma matsutake in northeastern China

Tricholoma matsutake is an ectomycorrhizal (ECM) fungus that produces economically important mushrooms. The study firstly applied SRAP technique into genetic diversity of T. matsutake. A total of 129 strains from 13 geographical locations in northeastern China, were amplified by using selected 12 primer pairs. The polymorphic band number amplified by each primer pair ranged from 7 to 13. In total 154 bands were observed, of which 118 were polymorphic (76.62%). Abundant genetic variation was detected within individual populations. Dongning maintained a higher genetic diversity while Hunchun was lower. The analyses found a significant positive correlation between genetic distance and geographical distance and no correlation between genetic distance and altitudinal differences among populations. Based on the UPGMA cluster diagram, the 13 populations may be divided with the genetic distance of 0.035 into three groups.Key words: Genetic diversity, Tricholoma matsutake, fungi, sequence related amplified polymorphism (SRAP)

A Computational Study of the Weak Galerkin Method for Second-Order Elliptic Equations

The weak Galerkin finite element method is a novel numerical method that was first proposed and analyzed by Wang and Ye for general second order elliptic problems on triangular meshes. The goal of this paper is to conduct a computational investigation for the weak Galerkin method for various model problems with more general finite element partitions. The numerical results confirm the theory established by Wang and Ye. The results also indicate that the weak Galerkin method is efficient, robust, and reliable in scientific computing.Comment: 19 page

Pressure Effect on the superconducting properties of LaO_{1-x}F_{x}FeAs(x=0.11) superconductor

Diamagnetic susceptibility measurements under high hydrostatic pressure (up to 1.03 GPa) were carried out on the newly discovered Fe-based superconductor LaO_{1-x}F_{x}FeAs(x=0.11). The transition temperature T_c, defined as the point at the maximum slope of superconducting transition, was enhanced almost linearly by hydrostatic pressure, yielding a dT_c/dP of about 1.2 K/GPa. Differential diamagnetic susceptibility curves indicate that the underlying superconducting state is complicated. It is suggested that pressure plays an important role on pushing low T_c superconducting phase toward the main (optimal) superconducting phase.Comment: 7 pages, 4 figure

The Content of the Basic/Required MIS Course in a Latin-American MBA

The panel is about the basic/required MIS course in Latin-American MBA programs. Given the current insufficiency of qualified MIS faculty in Latin-America this course is frequently taught by faculty from other areas and its content is often highly technical. The panel (introduced and moderated by Dr. Carlos Ferran) will discuss the current and the ideal content of this course as well as avenues to move forward. Two panelists are resident faculty in Latin-American universities (Dr. Aurora Sanchez –UCNA in Chile– and Dr. David Montesinos –INCAE in Costa Rica–), one visits Latin-America regularly to teach MIS in MBA programs (Dr. Enrique Mu), and one is completely unrelated to Latin-America (Dr. Janis Gogan) who will question why the course should be any different to the ones taught elsewhere. The panel is of interest to Latin-American academics but also for any academic interested on what should be included in the basic/required MIS course in MBA programs regardless of geography

Universal cloning of continuous quantum variables

The cloning of quantum variables with continuous spectra is analyzed. A universal - or Gaussian - quantum cloning machine is exhibited that copies equally well the states of two conjugate variables such as position and momentum. It also duplicates all coherent states with a fidelity of 2/3. More generally, the copies are shown to obey a no-cloning Heisenberg-like uncertainty relation.Comment: 4 pages, RevTex. Minor revisions, added explicit cloning transformation, added reference

The activation energy determination in non-isothermal conditions for the solid-state phase transformation of 1035 steel

The activation energy of solid-state phase transformation for the steel has been evaluated by the isoconversional method. It is demonstrated that the linear fitting is a mathematically invalid procedure that generally invalidates the isoconversional method. As an alternative, we apply the advanced isoconversional method that can be used to determine the activation energy of solid-state phase transformation of 1035 steel. The activation energy determined by this method varies with the transformed phase fraction. The variation of the activation energy was interpreted by the nucleation and growth model. It is shown that the advanced isoconversional method can be recommended as a trustworthy way of determining the activation energy of solid-state phase transformation of 1035 steel

The activation energy determination in non-isothermal conditions for the solid-state phase transformation of 1035 steel

The activation energy of solid-state phase transformation for the steel has been evaluated by the isoconversional method. It is demonstrated that the linear fitting is a mathematically invalid procedure that generally invalidates the isoconversional method. As an alternative, we apply the advanced isoconversional method that can be used to determine the activation energy of solid-state phase transformation of 1035 steel. The activation energy determined by this method varies with the transformed phase fraction. The variation of the activation energy was interpreted by the nucleation and growth model. It is shown that the advanced isoconversional method can be recommended as a trustworthy way of determining the activation energy of solid-state phase transformation of 1035 steel

Threshold and non-linear behavior of lasers of Λ\Lambda and V - configurations

Dynamic properties of closed three level laser systems are investigated. Two schemes of pumping - $\Lambda$ and V - are considered. It is shown that the non-linear behavior of the photon number as a function of pump both near and far above threshold is crucially different for these two configurations. In particular, it is found that in the high pump regime laser can turn off in a phase-transition-like manner in both $\Lambda$ and V schemes.Comment: 9 pages, 5 figure

Specifying angular momentum and center of mass for vacuum initial data sets

We show that it is possible to perturb arbitrary vacuum asymptotically flat spacetimes to new ones having exactly the same energy and linear momentum, but with center of mass and angular momentum equal to any preassigned values measured with respect to a fixed affine frame at infinity. This is in contrast to the axisymmetric situation where a bound on the angular momentum by the mass has been shown to hold for black hole solutions. Our construction involves changing the solution at the linear level in a shell near infinity, and perturbing to impose the vacuum constraint equations. The procedure involves the perturbation correction of an approximate solution which is given explicitly.Comment: (v2) a minor change in the introduction and a remark added after Theorem 2.1; (v3) final version, appeared in Comm. Math. Phy