Advances in Condensed Matter Physics http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. (112) Surface of CuInSe2 Thin Films with Doped Cd Atoms Tue, 27 Jan 2015 07:25:05 +0000 http://www.hindawi.com/journals/acmp/2015/206501/ The doping behavior of Cd atoms in the CuInSe2 thin films and their influences on electronic structures are investigated. The doped Cd atoms replace Cu atoms and prefer to stay at the (112) surface of the thin films. They combine with Cu vacancies to form defect pairs due to low formation energy. The Cd atom does not by itself modify significantly the electronic structure of the surface, but the defect pairs have important influences. They result in a down shift of valence band maximum and form a hole barrier at the surface, which can prevent holes from reaching the surface and reduce the recombination of carriers. Bo Yin and Chaogang Lou Copyright © 2015 Bo Yin and Chaogang Lou. All rights reserved. Model of Reversible Breakdown in HfO2 Based on Fractal Patterns Thu, 22 Jan 2015 13:49:00 +0000 http://www.hindawi.com/journals/acmp/2015/136938/ We propose a model of the kinetics of reversible breakdown in metal-insulator-metal structures with afnia based on the growth of fractal patterns of defects when the insulator is subject to an external voltage. The probability that a defect is (or is not) generated and the position where it is generated depend on the electric field distribution. The new defect moves accordingly to fractal rules and attach to another defect in a tree branch. When the two electrodes sandwiching the insulating film are connected a conductive filament is formed and the breakdown takes place. The model is calibrated with experiments inducing metastable soft breakdown events in Pt/HfO2/Pt capacitors. P. Lorenzi, R. Rao, G. Romano, and F. Irrera Copyright © 2015 P. Lorenzi et al. All rights reserved. Collective Modes of an Ultracold 6Li-40K Mixture in an Optical Lattice Wed, 21 Jan 2015 06:30:21 +0000 http://www.hindawi.com/journals/acmp/2015/952852/ A low-energy theory of the Nambu-Goldstone excitation spectrum and the corresponding speed of sound of an interacting Fermi mixture of Lithium-6 and Potassium-40 atoms in a two-dimensional optical lattice at finite temperatures with the Fulde-Ferrell order parameter has been formulated. It is assumed that the two-species interacting Fermi gas is described by the one-band Hubbard Hamiltonian with an attractive on-site interaction. The discussion is restricted to the BCS side of the Feshbach resonance where the Fermi atoms exhibit superfluidity. The quartic on-site interaction is decoupled via a Hubbard-Stratonovich transformation by introducing a four-component boson field which mediates the Hubbard interaction. A functional integral technique and a Legendre transform are used to give a systematic derivation of the Schwinger-Dyson equations for the generalized single-particle Green’s function and the Bethe-Salpeter equation for the two-particle Green’s function and the associated collective modes. The numerical solution of the Bethe-Salpeter equation in the generalized random phase approximation shows that there exist two distinct sound velocities in the long-wavelength limit. In addition to low-energy (Goldstone) mode, the two-species Fermi gas has a superfluid phase revealed by two roton-like minima in the asymmetric collective-mode energy. Z. G. Koinov Copyright © 2015 Z. G. Koinov. All rights reserved. Selection Theory of Dendritic Growth with Anisotropic Diffusion Tue, 20 Jan 2015 08:28:39 +0000 http://www.hindawi.com/journals/acmp/2015/529036/ Dendritic patterns frequently arise when a crystal grows into its own undercooled melt. Latent heat released at the two-phase boundary is removed by some transport mechanism, and often the problem can be described by a simple diffusion model. Its analytic solution is based on a perturbation expansion about the case without capillary effects. The length scale of the pattern is determined by anisotropic surface tension, which provides the mechanism for stabilizing the dendrite. In the case of liquid crystals, diffusion can be anisotropic too. Growth is faster in the direction of less efficient heat transport (inverted growth). Any physical solution should include this feature. A simple spatial rescaling is used to reduce the bulk equation in 2D to the case of isotropic diffusion. Subsequently, an eigenvalue problem for the growth mode results from the interface conditions. The eigenvalue is calculated numerically and the selection problem of dendritic growth with anisotropic diffusion is solved. The length scale is predicted and a quantitative description of the inverted growth phenomenon is given. It is found that anisotropic diffusion cannot take the stabilizing role of anisotropic surface tension. Martin von Kurnatowski and Klaus Kassner Copyright © 2015 Martin von Kurnatowski and Klaus Kassner. All rights reserved. Phase Transitions of Binary Lipid Mixtures: A Combined Study by Adiabatic Scanning Calorimetry and Quartz Crystal Microbalance with Dissipation Monitoring Tue, 20 Jan 2015 06:52:26 +0000 http://www.hindawi.com/journals/acmp/2015/479318/ The phase transitions of binary lipid mixtures are studied by a combination of Peltier-element-based adiabatic scanning calorimetry (pASC) and quartz crystal microbalance with dissipation monitoring (QCM-D). pASC, a novel type of calorimeter, provides valuable and unambiguous information on the heat capacity and the enthalpy, whereas QCM-D is proposed as a genuine way of determining phase diagrams by analysing the temperature dependence of the viscosity. Two binary mixtures of phospholipids with the same polar head and differing in the alkyl chain length, DMPC + DPPC and DMPC + DSPC, are discussed. Both techniques give consistent phase diagrams, which compare well with literature results, showing their capability to map the phase behaviour of pure lipids as well as lipid mixtures. This work can be considered as a departure point for further investigations on more complex lipid mixtures displaying relevant phases such as the liquid-ordered phase and solid-lipid interfaces with biologically functional importance. P. Losada-Pérez, N. Mertens, B. de Medio-Vasconcelos, E. Slenders, J. Leys, M. Peeters, B. van Grinsven, J. Gruber, C. Glorieux, H. Pfeiffer, P. Wagner, and J. Thoen Copyright © 2015 P. Losada-Pérez et al. All rights reserved. Noise from Glauber Dynamics: Self-Consistent Interaction and Temperature Dependent Correlations Thu, 15 Jan 2015 11:20:38 +0000 http://www.hindawi.com/journals/acmp/2015/607021/ Low frequency flicker noise has been argued to occur in spatially extended metastable systems near a critical point (Bak et al., 1987). An Ising-Glauber model based method is suggested here to systematically obtain temperature dependent nth-order correlation functions for arbitrary interacting two-level systems (TLSs). This model is fully consistent with existing methods to calculate noise spectra from TLSs and complements them. However, with as such no a priori assumptions on the typical log normal distribution of fluctuation rates, it is shown that noise manifests in two different cases: first in the thermodynamic limit on a 2D lattice with long range antiferromagnetic interactions at low temperatures and second in the case of a statistical ensemble of finite-sized spin clusters representing disorder, but where each cluster is ordered due to ferromagnetic interactions. Amrit De Copyright © 2015 Amrit De. All rights reserved. Application of Ellipsometry to Control the Plasmachemical Synthesis of Thin TiONx Layers Tue, 13 Jan 2015 06:33:00 +0000 http://www.hindawi.com/journals/acmp/2015/709308/ Ellipsometry is often used to determine the characteristics of films. Ellipsometric studies may turn out to be ineffective because several solutions correspond to the same polarization angles. It is demonstrated that the ambiguity is not due to the physical limitations of the method but it has a purely mathematical character. So, additional information about the film is necessary to determine the absolute values of refractive index, attenuation, and thickness. F. N. Dultsev and E. A. Kolosovsky Copyright © 2015 F. N. Dultsev and E. A. Kolosovsky. All rights reserved. Tin-Doped Indium Oxide-Titania Core-Shell Nanostructures for Dye-Sensitized Solar Cells Tue, 30 Dec 2014 12:13:48 +0000 http://www.hindawi.com/journals/acmp/2014/903294/ Dye-sensitized solar cells (DSSCs) hold great promise in the pursuit of reliable and cheap renewable energy. In this work, tin-doped indium oxide (ITO)-TiO2 core-shell nanostructures are used as the photoanode for DSSCs. High-density, vertically aligned ITO nanowires are grown via a thermal evaporation method and TiO2 is coated on nanowire surfaces via TiCl4 treatment. It is found that high TiO2 annealing temperatures increase the crystallinity of TiO2 shell and suppress electron recombination in the core-shell nanostructures. High annealing temperatures also decrease dye loading. The highest efficiency of 3.39% is achieved at a TiO2 annealing temperature of 500°C. When HfO2 blocking layers are inserted between the core and shell of the nanowire, device efficiency is further increased to 5.83%, which is attributed to further suppression of electron recombination from ITO to the electrolyte. Open-circuit voltage decay (OCVD) measurements show that the electron lifetime increases by more than an order of magnitude upon HfO2 insertion. ITO-TiO2 core-shell nanostructures with HfO2 blocking layers are promising photoanodes for DSSCs. Luping Li, Cheng Xu, Yang Zhao, and Kirk J. Ziegler Copyright © 2014 Luping Li et al. All rights reserved. In and Ga Codoped ZnO Film as a Front Electrode for Thin Film Silicon Solar Cells Sun, 28 Dec 2014 07:03:35 +0000 http://www.hindawi.com/journals/acmp/2014/971528/ Doped ZnO thin films have attracted much attention in the research community as front-contact transparent conducting electrodes in thin film silicon solar cells. The prerequisite in both low resistivity and high transmittance in visible and near-infrared region for hydrogenated microcrystalline or amorphous/microcrystalline tandem thin film silicon solar cells has promoted further improvements of this material. In this work, we propose the combination of major Ga and minor In impurities codoped in ZnO film (IGZO) to improve the film optoelectronic properties. A wide range of Ga and In contents in sputtering targets was explored to find optimum optical and electrical properties of deposited films. The results show that an appropriate combination of In and Ga atoms in ZnO material, followed by in-air thermal annealing process, can enhance the crystallization, conductivity, and transmittance of IGZO thin films, which can be well used as front-contact electrodes in thin film silicon solar cells. Duy Phong Pham, Huu Truong Nguyen, Bach Thang Phan, Thi My Dung Cao, Van Dung Hoang, Vinh Ai Dao, Junsin Yi, and Cao Vinh Tran Copyright © 2014 Duy Phong Pham et al. All rights reserved. Laser and Ion Beams Interactions with Materials Mon, 22 Dec 2014 10:46:29 +0000 http://www.hindawi.com/journals/acmp/2014/890520/ Xiaotao Zu, Kai Sun, Wanguo Zheng, and Haiyan Xiao Copyright © 2014 Xiaotao Zu et al. All rights reserved. Theoretical Analysis and Computational Simulation of Advanced Structured Materials Thu, 18 Dec 2014 11:23:53 +0000 http://www.hindawi.com/journals/acmp/2014/367916/ Hanxing Zhu, Daniel Balint, and Zaoyang Guo Copyright © 2014 Hanxing Zhu et al. All rights reserved. Is There a Metamaterial Route to High Temperature Superconductivity? Thu, 04 Dec 2014 00:10:10 +0000 http://www.hindawi.com/journals/acmp/2014/479635/ Superconducting properties of a material such as electron-electron interactions and the critical temperature of superconducting transition can be expressed via the effective dielectric response function () of the material. Such a description is valid on the spatial scales below the superconducting coherence length (the size of the Cooper pair), which equals ∼100 nm in a typical BCS superconductor. Searching for natural materials exhibiting larger electron-electron interactions constitutes a traditional approach to high temperature superconductivity research. Here we point out that recently developed field of electromagnetic metamaterials deals with somewhat related task of dielectric response engineering on sub-100 nm scale. We argue that the metamaterial approach to dielectric response engineering may considerably increase the critical temperature of a composite superconductor-dielectric metamaterial. Igor I. Smolyaninov and Vera N. Smolyaninova Copyright © 2014 Igor I. Smolyaninov and Vera N. Smolyaninova. All rights reserved. Numerical Study of Membrane Configurations Sun, 30 Nov 2014 00:10:21 +0000 http://www.hindawi.com/journals/acmp/2014/373674/ We studied biological membranes of spherical topology within the framework of the spontaneous curvature model. Both Monte Carlo simulations and the numerical minimization of the curvature energy were used to obtain the shapes of the vesicles. The shapes of the vesicles and their energy were calculated for different values of the reduced volume. The vesicles which exhibit in-plane ordering were also studied. Minimal models have been developed in order to study the orientational ordering in colloids coated with a thin sheet of nematic liquid crystal (nematic shells). The topological defects are always present on the surfaces with the topology of a sphere. The location of the topological defects depends strongly on the curvature of the surface. We studied the nematic ordering and the formation of topological defects on vesicles obtained by the minimization of the spontaneous curvature energy. Luka Mesarec, Miha Fošnarič, Samo Penič, Veronika Kralj Iglič, Samo Kralj, Wojciech Góźdź, and Aleš Iglič Copyright © 2014 Luka Mesarec et al. All rights reserved. Field Induced Memory Effects in Random Nematics Sun, 30 Nov 2014 00:10:19 +0000 http://www.hindawi.com/journals/acmp/2014/423693/ We studied numerically external field induced memory effects in randomly perturbed nematic liquid crystals. Random anisotropy nematic-type lattice model was used. The impurities imposing orientational disorder were randomly spatially distributed with the concentration below the percolation threshold. Simulations were carried for finite temperatures, where we varied , interaction strength between LC molecules, and impurities and external field . In the plane we determined lines separating short range—quasi long range and quasi long range—long range order. Furthermore, crossover regime separating external field and random field dominated regime was estimated. We calculated remanent nematic ordering in samples at as a function of the previously experienced external field strength . Amid Ranjkesh, Milan Ambrožič, Samo Kralj, and T. J. Sluckin Copyright © 2014 Amid Ranjkesh et al. All rights reserved. Investigations on Growth, Optical and Thermal Properties of Sulphamic Acid Single Crystals Tue, 25 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/acmp/2014/950467/ Single crystals of sulphamic acid of 11 × 7 × 3 mm3 dimension were successfully grown by slow evaporation technique. The crystal structure of grown crystals was confirmed by single crystal X-ray diffraction analysis. The presence of functional groups in the crystal lattice has been qualitatively determined by FT-IR and FT-Raman analyses. Theoretical group factor analysis predicts the possible modes of vibrations. The optical transmission spectroscopy (UV-Vis) clearly evidences the suitability of this material for optical application. The thermal behaviour of the crystal was studied by thermogravimetric (TG) and differential scanning calorimetric (DSC) studies. The nonlinear optical (NLO) characteristic of this material was explored by the second harmonic generation (SHG) conversion efficiency. D. Jaishree, G. Kanchana, and R. Kesavasamy Copyright © 2014 D. Jaishree et al. All rights reserved. Investigation of Structural, Magnetic, and Optical Properties of ZnO Codoped with Co and Cd Mon, 24 Nov 2014 06:32:12 +0000 http://www.hindawi.com/journals/acmp/2014/362864/ Co and Cd have been codoped in ZnO using a simple solid state reaction technique to synthesize dilute magnetic oxide semiconductors of composition Zn0.9Co0.1−xCdxO ( with an increment of 0.02). Hexagonal wurtzite structure has been obtained for samples up to , using X-ray diffractometry. However, at and 0.1, secondary peak of CdO is observed. Raman spectra of the samples have been obtained in 200–800 cm−1 range. UV-VIS spectrophotometer is used to study the optical properties, which shows that band gap energy decreases with the increase in Cd concentration. A weak ferromagnetic behavior was evident which decreased further by adding Cd in the series. Room temperature resistivity measurements performed using four-point probe technique showed that their values lie in the semiconductor range. Structural morphology of the samples has been investigated by a scanning electron microscope and grain size has been determined. Raman spectra and Fourier transform infrared spectroscopy revealed the successful incorporation of Co and Cd ions into the host ZnO lattice. Lubna Mustafa, Safia Anjum, Salma Waseem, Rehana Zia, Rameesha Choudhry, Shahid M. Ramay, Asif Mahmood, Shahid Atiq, and Salah Ud-Din Khan Copyright © 2014 Lubna Mustafa et al. All rights reserved. The Gap and the Upper Critical Field as Function of Doping for High- Cuprates Mon, 24 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/acmp/2014/212895/ The relation between the -wave superconducting gap and the specific heat obtained with the Volovik effect is used to determine the upper critical field as doping function, for high-temperature superconductors. A two-components model with -wave symmetry, within the BCS framework, is introduced to describe the superconducting state. Generalized Fermi surface topologies are used in order to increase the density of states at the Fermi level, allowing the high- values observed. The electron-phonon interaction is considered the most relevant mechanism for the high- cuprates, where the available phonon energy is provided by the half-breathing modes. The energy gap values calculated with this model are introduced to describe the variation of the upper critical field as function of doping, for . S. Orozco, R. M. Méndez-Moreno, and M. A. Ortiz Copyright © 2014 S. Orozco et al. All rights reserved. Composite Operator Method Analysis of the Underdoped Cuprates Puzzle Mon, 10 Nov 2014 12:29:05 +0000 http://www.hindawi.com/journals/acmp/2014/515698/ The microscopical analysis of the unconventional and puzzling physics of the underdoped cuprates, as carried out lately by means of the composite operator method (COM) applied to the 2D Hubbard model, is reviewed and systematized. The 2D Hubbard model has been adopted as it has been considered the minimal model capable of describing the most peculiar features of cuprates held responsible for their anomalous behavior. COM is designed to endorse, since its foundation, the systematic emergence in any SCS of new elementary excitations described by composite operators obeying noncanonical algebras. In this case (underdoped cuprates—2D Hubbard model), the residual interactions—beyond a 2-pole approximation—between the new elementary electronic excitations, dictated by the strong local Coulomb repulsion and well described by the two Hubbard composite operators, have been treated within the noncrossing approximation. Given this recipe and exploiting the few unknowns to enforce the Pauli principle content in the solution, it is possible to qualitatively describe some of the anomalous features of high-Tc cuprate superconductors such as large versus small Fermi surface dichotomy, Fermi surface deconstruction (appearance of Fermi arcs), nodal versus antinodal physics, pseudogap(s), and kinks in the electronic dispersion. The resulting scenario envisages a smooth crossover between an ordinary weakly interacting metal sustaining weak, short-range antiferromagnetic correlations in the overdoped regime to an unconventional poor metal characterized by very strong, long-but-finite-range antiferromagnetic correlations leading to momentum-selective non-Fermi liquid features as well as to the opening of a pseudogap and to the striking differences between the nodal and the antinodal dynamics in the underdoped regime. Adolfo Avella Copyright © 2014 Adolfo Avella. All rights reserved. Atomistic Simulation of Intrinsic Defects and Trivalent and Tetravalent Ion Doping in Hydroxyapatite Sun, 12 Oct 2014 12:12:08 +0000 http://www.hindawi.com/journals/acmp/2014/609024/ Atomistic simulation techniques have been employed in order to investigate key issues related to intrinsic defects and a variety of dopants from trivalent and tetravalent ions. The most favorable intrinsic defect is determined to be a scheme involving calcium and hydroxyl vacancies. It is found that trivalent ions have an energetic preference for the Ca site, while tetravalent ions can enter P sites. Charge compensation is predicted to occur basically via three schemes. In general, the charge compensation via the formation of calcium vacancies is more favorable. Trivalent dopant ions are more stable than tetravalent dopants. Ricardo D. S. Santos and Marcos V. dos S. Rezende Copyright © 2014 Ricardo D. S. Santos and Marcos V. dos S. Rezende. All rights reserved. The Origin and Coupling Mechanism of the Magnetoelectric Effect in TMCl2-4SC(NH2)2 (TM = Ni and Co) Mon, 08 Sep 2014 00:00:00 +0000 http://www.hindawi.com/journals/acmp/2014/512621/ Most research on multiferroics and magnetoelectric effects to date has focused on inorganic oxides. Molecule-based materials are a relatively new field in which to search for magnetoelectric multiferroics and to explore new coupling mechanisms between electric and magnetic order. We present magnetoelectric behavior in NiCl2-4SC(NH2)2 (DTN) and CoCl2-4SC(NH2)2 (DTC). These compounds form tetragonal structures where the transition metal ion (Ni or Co) is surrounded by four electrically polar thiourea molecules [SC(NH2)2]. By tracking the magnetic and electric properties of these compounds as a function of magnetic field, we gain insights into the coupling mechanism by observing that, in DTN, the electric polarization tracks the magnetic ordering, whereas in DTC it does not. For DTN, all electrically polar thiourea molecules tilt in the same direction along the c-axis, breaking spatial-inversion symmetry, whereas, for DTC, two thiourea molecules tilt up and two tilt down with respect to c-axis, perfectly canceling the net electrical polarization. Thus, the magnetoelectric coupling mechanism in DTN is likely a magnetostrictive adjustment of the thiourea molecule orientation in response to magnetic order. Eundeok Mun, Jason Wilcox, Jamie L. Manson, Brian Scott, Paul Tobash, and Vivien S. Zapf Copyright © 2014 Eundeok Mun et al. All rights reserved. Spatially Resolved Cathodoluminescence in the Vicinity of Defects in the High-Efficiency InGaN/GaN Blue Light Emitting Diodes Mon, 01 Sep 2014 07:47:49 +0000 http://www.hindawi.com/journals/acmp/2014/671210/ In addition to the standard 447 nm blue emission from the InGaN/GaN multiple quantum wells, a high-energy shoulder is clearly observed in cathodoluminescence spectra of the high-efficiency InGaN/GaN blue light emitting diodes grown on sapphire substrates by metalorganic chemical vapor deposition. Monochromatic cathodoluminescence images of the samples measured at low temperature reveal a competition between the two emissions in the vicinity of the dislocations. The high-energy emission is dominant at the regions near the dislocation cores, while the blue emission is enhanced around the dislocation edges. The high-energy emission region is considered as a potential barrier that prevents the carriers for the blue emission from nonradiatively recombining at the dislocations. Manh-Ha Doan and Jaejin Lee Copyright © 2014 Manh-Ha Doan and Jaejin Lee. All rights reserved. Influence of Codoping on the Optical Properties of ZnO Thin Films Synthesized on Glass Substrate by Chemical Bath Deposition Method Sun, 31 Aug 2014 12:07:12 +0000 http://www.hindawi.com/journals/acmp/2014/761960/ Fe and K simultaneously doped ZnO thin films Zn0.99 K0.01 (Fe)x O (, 2, 3, and 4%) were synthesized by chemical bath deposition method. The XRD investigation reveals that all the doped ZnO thin films are in hexagonal wurtzite crystal structure without impurity phases. With increase in Fe concentration, the growth of thin films along c axis is evident from the XRD which indicates the increase in intensity along (002) direction. The same is visible from the surface morphology which shows the formation of hexagonal structure for higher Fe concentration. The topography shows gradual variation with Fe incorporation. The optical energy band gap obtained from the transmittance spectrum decreases from 3.42 to 3.06‚ÄČeV with increase in Fe concentration indicating the red shift and this trend is consistent with the earlier experimental results. The UV emission is centered around 3.59‚ÄČeV. The optical constants such as refractive index, extinction coefficient, and absorption coefficient which are essential for the optoelectronic applications were also determined. G. Shanmuganathan and I. B. Shameem Banu Copyright © 2014 G. Shanmuganathan and I. B. Shameem Banu. All rights reserved. Structural, Electronic, and Optical Properties of Functional Metal Oxides Sun, 31 Aug 2014 08:52:34 +0000 http://www.hindawi.com/journals/acmp/2014/134951/ Jianhua Hao, Nian X. Sun, Jianrong Qiu, and Danyang Wang Copyright © 2014 Jianhua Hao et al. All rights reserved. The Low Temperature Specific Heat of Pr0.65Ca0.35MnO3 Mon, 25 Aug 2014 08:05:05 +0000 http://www.hindawi.com/journals/acmp/2014/394296/ The low temperature specific heat of polycrystalline perovskite-type Pr0.65Ca0.35MnO3 manganese oxide has been investigated experimentally. It is found that the low temperature electron specific heat in zero magnetic field is obviously larger than that of ordinary rare-earth manganites oxide. To get the contribution of phonon to the specific heat precisely, the lattice specific heat is calculated by Debye model fitting. Results confirm that the low temperature specific heat of Pr0.65Ca0.35MnO3 is related to the itinerant electrons in ferromagnetic clusters and the disorder in the sample. Zhiyong Han and Zhenzhu Jing Copyright © 2014 Zhiyong Han and Zhenzhu Jing. All rights reserved. Laser-Induced Point Defects in Fused Silica Irradiated by UV Laser in Vacuum Sun, 17 Aug 2014 12:27:55 +0000 http://www.hindawi.com/journals/acmp/2014/853764/ High-purity fused silica irradiated by third harmonic of the Nd:YAG laser in vacuum with different laser pulse parameters was studied experimentally. Laser-induced defects are investigated by UV spectroscopy, and fluorescence spectra and correlated to the structural modifications in the glass matrix through Raman spectroscopy. Results show that, for laser fluence below laser-induced damage threshold (LIDT), the absorbance and intensity of fluorescence bands increase with laser energies and/or number of laser pulses, which indicates that laser-induced defects are enhanced by laser energies and/or number of laser pulses in vacuum. The optical properties of these point defects were discussed in detail. Xiaoyan Zhou, Xinda Zhou, Jin Huang, Qiang Cheng, Fengrui Wang, Xin Ye, Xiaodong Jiang, and Weidong Wu Copyright © 2014 Xiaoyan Zhou et al. All rights reserved. Cracking Tendency Prediction of High-Performance Cementitious Materials Tue, 05 Aug 2014 09:50:29 +0000 http://www.hindawi.com/journals/acmp/2014/591084/ The constraint ring test is widely used to assess the cracking potential for early-age cementitious materials. In this paper, the analytical expressions based on elastic mechanism are presented to estimate the residual stresses of the restrained mortar ring by considering the comprehensive effects of hydration heat, autogenous and drying shrinkage, creeping, and restraint. In the present analytical method, the stress field of the restrained ring is treated as the superposition of those caused by hydration heat, external restraint, autogenous and drying shrinkage, and creep. The factors including the properties of materials, environmental parameters such as relative humidity and temperature, the geometry effect of specimen, and the relative constraint effects of steel ring to mortar ring, are taken into account to predict the strain development with age of mortar. The temperature of the ring, the elastic modulus, the creep strain, and the split tensile strength are measured to validate the model. The age of cracking is predicted by comparing the estimated maximum tensile stress of the restrained mortar ring with the measured split tensile strength of specimen. The suitability of the present analytical method is assessed by comparing with the restraint ring test and a soundly good agreement is observed. Ke Chen, Hui Hu, Ke Chen, Zhaohui Chen, and Xin Wang Copyright © 2014 Ke Chen et al. All rights reserved. Dynamics and Matter-Wave Solitons in Bose-Einstein Condensates with Two- and Three-Body Interactions Tue, 05 Aug 2014 08:15:41 +0000 http://www.hindawi.com/journals/acmp/2014/307135/ By means of similarity transformation, this paper proposes the matter-wave soliton solutions and dynamics of the variable coefficient cubic-quintic nonlinear Schrödinger equation arising from Bose-Einstein condensates with time-dependent two- and three-body interactions. It is found that, under the effect of time-dependent two- and three-body interaction and harmonic potential with time-dependent frequency, the density of atom condensates will gradually diminish and finally collapse. Jing Chen, Jie Yang, and Lu Zhang Copyright © 2014 Jing Chen et al. All rights reserved. First Principles Study of Cerium Monochalcogenides Mon, 21 Jul 2014 09:40:30 +0000 http://www.hindawi.com/journals/acmp/2014/780245/ A theoretical investigation of structural, magnetic, electronic, and lattice dynamical properties of cerium monochalcogenides using the generalized gradient approximation (GGA) + U within ultrasoft pseudopotentials and a plane-wave basis is presented. All the calculated quantities, except the local magnetic moments, are found to be in good agreement with the experimental data. The lattice dynamical results indicate a strong chalcogenide dependence for the anomalous features of the phonon dispersions. Recep Eryiğit Copyright © 2014 Recep Eryiğit. All rights reserved. Full Aperture CO2 Laser Process to Improve Laser Damage Resistance of Fused Silica Optical Surface Thu, 17 Jul 2014 00:00:00 +0000 http://www.hindawi.com/journals/acmp/2014/676108/ An improved method is presented to scan the full-aperture optical surface rapidly by using galvanometer steering mirrors. In contrast to the previous studies, the scanning velocity is faster by several orders of magnitude. The velocity is chosen to allow little thermodeposition thus providing small and uniform residual stress. An appropriate power density is set to obtain a lower processing temperature. The proper parameters can help to prevent optical surface from fracturing during operation at high laser flux. S-on-1 damage test results show that the damage threshold of scanned area is approximately 40% higher than that of untreated area. Wei Liao, Chuanchao Zhang, Xiaofen Sun, Lijuan Zhang, and Xiaodong Yuan Copyright © 2014 Wei Liao et al. All rights reserved. Laser-Induced Damage Initiation and Growth of Optical Materials Wed, 16 Jul 2014 10:26:02 +0000 http://www.hindawi.com/journals/acmp/2014/364627/ The lifetime of optical components is determined by the combination of laser-induced damage initiation probability and damage propagation rate during subsequent laser shots. This paper reviews both theoretical and experimental investigations on laser-induced damage initiation and growth at the surface of optics. The damage mechanism is generally considered as thermal absorption and electron avalanche, which play dominant roles for the different laser pulse durations. The typical damage morphology in the surface of components observed in experiments is also closely related to the damage mechanism. The damage crater in thermal absorption process, which can be estimated by thermal diffusion model, is typical distortion, melting, and ablation debris often with an elevated rim caused by melted material flow and resolidification. However, damage initiated by electron avalanche is often accompanied by generation of plasma, crush, and fracture, which can be explained by thermal explosion model. Damage growth at rear surface of components is extremely severe which can be explained by several models, such as fireball growth, impact crater, brittle fracture, and electric field enhancement. All the physical effects are not independent but mutually coupling. Developing theoretical models of multiphysics coupling are an important trend for future theoretical research. Meanwhile, more attention should be paid to integrated analysis both in theory and experiment. Jingxia Yu, Xia Xiang, Shaobo He, Xiaodong Yuan, Wanguo Zheng, Haibing Lü, and Xiaotao Zu Copyright © 2014 Jingxia Yu et al. All rights reserved.