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Zn 2 SnO 4 -doped BaTiO 3 ceramics were prepared as dielectric material though a conventional solid state reaction method. The room temperature dielectric constant was improved by Zn 2 SnO 4 doping, with the appearance of diffuse phase transition and reduced dielectric loss. More importantly, the temperature stability of BaTiO 3 ceramics (Δ C / C 25°C ) was modified by varying doping contents. The temperature dependence of sample with 2% doping contents satisfied the Electronic Industries Alliance Y5V temperature characteristic specification and was near the X7R specification. The SEM micrographs indicate that the BaTiO 3 solid solution has a homogeneous fine-grained microstructure with grain size < 1 μm and X-ray diffraction pattern suggest that the sample with 2% Zn 2 SnO 4 doping contents have a tetragonal phase at RT. DPT was resulted from element substitution of Ti 4+ with Sn 4+ , as lattice parameters increasing under inter-grain stress. Results of impedance spectroscopic analysis suggest the presence of two relaxation mechanisms. One was originated from the dipolar polarization in the grain, and the other was related with the hopping charge carriers of oxygen vacancy in the grain boundary. The dielectric loss over a wide temperature range was modified by the activation energies of the two type relaxation mechanisms. [ABSTRACT FROM AUTHOR]

The influence of stress on the spontaneous polarization in two-dimensional Bi4Ti3O12 (BiT) films is investigated by modified Landau—Devonshire thermodynamic theory. Three orientation cases of BiT unit, nine ferroelectric phases are discussed under the mechanism of strain-polarization coupling. Results show that the effect of stress on out-of-plane spontaneous polarization for all cases is small and can not clarify the origin of the effect of external stress on the net-switched charge in Nd- and La-doped Bi4Ti3O12 films. So there is a need to consider stress-induced reorientation of domains. [ABSTRACT FROM AUTHOR]

SnO2:Cu memristor devices were fabricated to investigate the influence of Frenkel defects on endurance behavior. We controlled the oxygen pressure during pulsed laser deposition to obtain different Frenkel defect conditions. For SnO2:Cu devices with homogeneous Frenkel defects, high-resistance state (HRS) fatigue was observed with increasing switching cycles due to the reduction of interfacial barriers caused by unrecoverable fragments of conductive filaments. In bilayer SnO2:Cu devices with Frenkel defect concentration gradients, the vertical Fick force resulting from the concentration gradient can drive mobile oxygen ions to restrain the formation of unrecoverable fragments. Thus, HRS fatigue was improved by restraining the reduction of interfacial barriers. When the gradient becomes large, the bilayer devices demonstrate HRS rise and stuck switching in several switching cycles. In this case, the Fick force may dominate the diffusion of mobile oxygen ions, leading to the overfilling of oxygen vacancies at the interface and an increase in interfacial barriers. [ABSTRACT FROM AUTHOR]

Abstract: Both experiment and theory have shown that the stress has a notable impact on the polarization of Nd-doped Bi4Ti3O12 films. In this paper, thermodynamic theory is used to study the effect of stress on the dielectric constants of Bi4Ti3O12 films at room temperature with a two-dimensional model. Results indicate that the change of the dielectric constant for a-phase induced by the lattice distortion is far greater than that for c-phase. Considering the domain reorientation, the external tensile stress may lead to an obvious decrease in the effective dielectric constant of Bi4Ti3O12 films. [Copyright &y& Elsevier]

Abstract: Thermodynamic theory has been used to explain quantitatively the coexistence of tetragonal and rhombohedral phases in Zr-rich Pb(Zr, Ti)O3 (PZT) films grown on a compressive substrate. The key is to consider a set of gradient thermal stresses imposed on the films. The “stress-temperature” phase diagrams were developed for PZT films of several different compositions (Ti/Zr=20/80, 30/70, 40/60, 50/50). The characteristic feature of the phase diagrams for Zr-rich PZT films is the coexistence of tetragonal and rhombohedral phases in the compressive stress region. The volume fractions of the rhombohedral phase were calculated for the Zr-rich PZT films grown on MgO substrate. The result agrees with the experiment. [Copyright &y& Elsevier]

The effect of spatially modulated interaction on quantum phase transition in one-dimensional interacting spinless fermion system is theoretically investigated by exact diagonalization and density matrix renormalization group method. Our calculations show that the periodically modulated interaction can drive the spinless fermion system into topological charge density wave state. The topological state is encoded by quasiparticle end states and the fractional quantized e/2 end charges, and characterized by Berry phase and Chern number. The quasiparticle energy spectra as a function of modulated interaction period appears a stunning fractal-like structure. For the quasi-periodic case, the topological phase transition can also occur. In a word, the spatially modulated interaction can be a new elegant avenue towards realizing to interacting topological phases. [ABSTRACT FROM AUTHOR]

Investigates the formation behavior of donors associated with oxygen in nitrogen-doped and undoped Czochralski (CZ) silicon by means of electrical and infrared measurements at low temperatures. Use of CZ single crystal silicon in the microelectronic industry; Experimental details; Findings of the study.

ST-xZS ceramics were prepared by solid-state sintering and have high temperature dielectric relaxation behavior at the temperature ranges of 300 °C–500 °C. We explore the origin of high temperature dielectric relaxation behavior of samples by activation energy calculation, XPS energy spectrum analysis and oxygen treatment experiment. We get a conclusion that the dielectric relaxation of pure ST ceramics comes from the migration of Vo. However, with the increase of ZS content, the dielectric relaxation related to Vo migration is gradually transformed into the influence of Ti4+ ion polarization, and the possible causes of relaxation behavior dependence are analyzed in detail. [ABSTRACT FROM AUTHOR]

Hexokinase 2 (HK2) binds to Voltage-Dependent Anion Channel 1 (VDAC1) on mitochondrial outer membrane (MOM) to facilitate a preferential access of ATP to HK2 for glycolysis, in order to maintain a constant energy source for cell proliferation in cancer especially. While previous studies have discovered that the VDAC1 N-terminal helix is responsible for regulating molecules from within mitochondria to cytoplasm, the molecular mechanism of how HK2 is able to regulate the ATP access remains elusive. We hereby propose a model for the HK2-VDAC1 association. The model is then subjected to molecular dynamics (MD) simulations, where we probe the effect of HK2 binding on the mobility of the VDAC1 N-terminal helix. Results from the simulations show that HK2 binding restricts the movement of the VDAC1 N-terminal helix. As a result, VDAC1 is kept in the open state most of the time and probably allows a constant supply of ATP to HK2 for glycolysis. [ABSTRACT FROM AUTHOR]

In this work, we studied the evolution of vacancy-like defects and the formation of brittle precipitates in a reduced-activation V−Cr−Mn medium-entropy alloy. The evolution of local electronic circumstances around Cr and Mn enrichments, the vacancy defects, and the CrMn3 precipitates were characterized by using scanning electron microscopy with energy-dispersive spectroscopy, X-ray diffraction, and positron annihilation spectroscopy. The microstructure measurements showed that the Mn and Cr enrichments in the as-cast sample significantly evolved with temperature, i.e., from 400 °C, the Cr/Mn-segregated regions gradually dissolved into the matrix and then disappeared, and from 900 °C to 1000 °C, they existed as CrMn3 precipitates. The crystallite size of the phase corresponding to CrMn3 precipitates was about 29.4 nm at 900 °C and 43.7 nm at 1000 °C. The positron annihilation lifetime results demonstrated that the vacancies mediated the migration of Cr and Mn, and Cr and Mn segregation finally led to the formation of CrMn3 precipitates. The coincidence Doppler broadening results showed that the characteristic peak moved to the low-momentum direction, due to an increase in the size of the vacancy defects at the interface and the formation of CrMn3 precipitates. [ABSTRACT FROM AUTHOR]

We synthesized lead-free (1 − x) CaZrO3– x SrTiO3 solid-solution ceramics and studied their structure, dielectric and energy storage properties. X-ray diffraction and scanning electron microscope reveal the microstructure of the samples. A high temperature dielectric relaxation behavior at the temperature ranges of 200 ∘ C–550 ∘ C is found for x = 0. 3 , 0.5 and 0.7 samples. We explore that the origin of high temperature dielectric relaxation behavior is related to the migration of oxygen vacancies by Arrhenius law and oxygen treatment experiment. Moreover, with the increase of SrTiO3 content, the 0.3CaZrO3–0.7SrTiO3 exhibits high dielectric constant ( = 3 6 4 5 at 1 kHz), low dielectric loss (tan δ = 0. 0 0 0 8 1 at 1 kHz), good energy density ( W rec = 1. 2 9 J/cm 3) and high efficiency (η = 8 7. 7 %) simultaneously, and the possible causes of energy storage behavior dependence are analyzed in detail. [ABSTRACT FROM AUTHOR]

Within the framework of Pertsev's thermodynamic theory, the equilibrium polarization states and the physical properties of single-domain Pb(Zr0.35Ti0.65)O3 (PZT) thin films epitaxially grown on dissimilar cubic substrates are investigated. The "misfit strain-temperature" phase diagrams are obtained for the films. The presence of stability range of the rhombohedral phase is the characteristic feature of these phase diagrams, which separates the stability ranges of the tetragonal phase and the orthorhombic phase. The coexistence of the rhombohedral phase and the tetragonal phase in PZT film can be explained by Pertsev's theory with the gradient strain case with a suitable stress form. [ABSTRACT FROM AUTHOR]

Abstract: Within the framework of modified Landau–Devonshire thermodynamic theory, the equilibrium polarization states and physical properties of single-domain Pb(Zr1-xTix)O3 (PZT) thin films epitaxially grown on dissimilar cubic substrates are investigated. The “misfit strain-temperature” phase diagrams are obtained for several different compositions (x =0.75, 0.65 and 0.55) of PZT films. The presence of stability range of the monoclinic phase is the characteristic feature of these phase diagrams, which separates the stability ranges of the tetragonal phase and the orthorhombic phase. Further analysis shows that the monoclinic phase widens with the increase of Zr content, and meanwhile the center shifts from positive values of the misfit strain towards zero. [Copyright &y& Elsevier]

Sr 1 − 3 x / 2 La x TiO 3 (SLTO) ceramics (x = 0.05, 0.10, 0.15) were prepared with giant dielectric constant by the traditional solid-state method at 1350 ∘ C. The temperature dependence of the dielectric constant was obtained at the temperature ranging from 29 ∘ C to 500 ∘ C and the frequency ranging from 2 kHz to 2 MHz. Two sets of relaxation peaks appear in the low temperature (region I) and the high temperature (region II), respectively. For region I, we conclude that the relaxation behavior is related to the oxygen vacancy migration. For region II, the two relaxation processes are caused by grain boundary for high frequency and Sr or Ti defects at grain interior for low frequency. With the doping amount reaching 0.15, the relaxation peaks disappear and become a common phase transition because of the aggravation of lattice distortion. These possible physical mechanisms of two sets of relaxation peaks are briefly discussed. [ABSTRACT FROM AUTHOR]

Pr-doped SrTiO3 ceramics were fabricated by the conventional solid-state reaction method. Pr-doping greatly decreased the lattice parameters and the average grain size of SrTiO3 ceramics sample. Two thermally activated dielectric relaxations were found for the low- and high-temperature relaxations, respectively. By means of a detailed analysis, the low-temperature relaxation was ascribed to the electric hopping between Pr3+ and Pr4+ induced by the Pr-doping, and the origin of the high-temperature relaxation was changed from oxygen vacancies to the polar nanoregions with the increase of Pr content. [ABSTRACT FROM AUTHOR]

• Polarizable force fields PHB and SFC were applied to simulate two β-hairpins. • Their effects on side chain-side chain interaction were examined. • Future force fields require consideration of both backbone H bonds and side chains. In view of the recent development of polarizable force fields namely polarizable hydrogen bond (PHB) and semi-fluctuating charge (SFC) developed by Zhang's group, we would like to explore the effects of these two models on side chain-side chain interactions through the simulation of two β-hairpins. The results show that the PHB model strengthens but the SFC model weakens side chain-side chain interactions in our studies. Through this study, we aim to have a more comprehensive understanding of these two models which only focus on the charge updating of backbone atoms. [ABSTRACT FROM AUTHOR]

The mechanical strength in germanium-doped Czochralski silicon (GCz-Si) wafers has been investigated through the on-line warpage statistics analysis, indentation tests, and fracture structure measurements. It was found that the wafer warpage during manufacturing processes could be statistically suppressed by the germanium doping slightly. The enhancement effect of germanium doping on the mechanical strength in GCz-Si wafers could be shown obviously when the germanium concentration was higher than 1018 cm-3. Meanwhile, the fracture strength for both the as-grown and the postannealed GCz-Si wafers might be greater compared to that of the conventional Czochralski (Cz-Si) wafers. Moreover, the generation and mobilization of the dislocations induced by indentation in Cz-Si wafers could be suppressed by the germanium doping. These phenomena are interpreted through a dislocation pinning-up effect associated with the smaller-sized higher-density oxygen precipitates formed in GCz-Si wafers. [ABSTRACT FROM AUTHOR]

Grown-in defects including oxygen precipitates and voids in nitrogen-doped Czochralski (NCZ) silicon have been investigated. It was found that the formation of grown-in oxygen precipitates in NCZ silicon can be divided into two stages. The large precipitates supposed to be enhanced by N[sub 2]-V[sub 2]-O[sub χ] complexes are generated around 1150 °C, while the small precipitates supposed to be enhanced by N[sub m]O[sub n] complexes are formed at 750 °C and below. Moreover, it was revealed that the oxygen precipitation behavior in the mixed-type NCZ silicon, which contains vacancy-type and interstitial-type defects distinguished by an OSF-ring in the oxidized wafer, is in sharp contrast to that in the mixed-type Czochralski (CZ) silicon, when subjected to one-step high temperature annealing (1050 °C/32 h) and two-step annealing (800 °C/4 h+ 1050 °C/16 h). On the other hand, it was found that, compared with CZ silicon, NCZ silicon has much denser crystal originated particles in smaller sizes, which were verified to have been annihilated at relatively lower temperatures. Based on the experimentally found phenomena, a tentative model that takes into account the formation of nitrogen-related complexes involving oxygen atoms and vacancies, void formation, and oxygen precipitation is presented. [ABSTRACT FROM AUTHOR]

Abstract This letter reports the structural, dielectric, ferroelectric, and magnetic properties of Fe substituted nonstoichiometric STO ceramics. X-ray diffraction and Scanning electron microscope reveal the microstructure of the samples. The room temperature multiferroicity of the Fe-doped Ti-rich STO ceramics is successfully realized by M-H hysteresis loop, P-E hysteresis loop and magnetodielectric measurement. The origins of ferroelectricity may be related to the lattice distortions and antisite-like defects with net local dipoles. The ferromagnetism are mainly contributed by the competitions among the double exchange interactions, super-exchange interactions and the non-linear ferromagnetic exchange coupling. In addition, the ordered spin arrangement of the ferromagnetism is formed by the exchange interaction of Fe atom using first principle simulations. Highlights • The influence of Fe-doped STO at both A and B sites is different. • The room multiferroics properties are successfully realized in STO ceramics. • The origin of ferromagnetism is analyzed by first principle simulations. [ABSTRACT FROM AUTHOR]

SrTiO 3 has received increasing attention duo to the fact that small perturbation can produce outstanding physical properties. Nonstoichiometric SrTiO 3 ceramics have been prepared in the range of Sr/Ti = 1.064–0.943. Their dielectric behaviors are investigated in the temperature range of 30–500 °C and in the frequency range 100 Hz to 2 MHz. It is observed that the two types of dielectric relaxation processes are caused by polar nanoregions associated with Sr non-stoichiometry and variable range hopping behavior associated with the dipolar effects for Sr/Ti>1 and Sr/Ti<1 ceramics samples, respectively. Our findings imply that the cation vacancy may be responsible for the adjusted properties in nonstoichiometric SrTiO 3 . [ABSTRACT FROM AUTHOR]

This paper presents a systematic study on the energetic and electronic structure of the Al(111)/6H-SiC(0001) interfaces by using first-principles calculation with density functional theory (DFT). There are all three situations for no-vacuum layer of Al/SiC superlattics, and two cases of C-terminated and Si-terminated interfaces are compared and analyzed. Through the density of states analysis, the initial information of interface combination is obtained. Then the supercells are stretched vertically along the z-axis, and the fracture of the interface is obtained, and it is pointed out that C-terminated SiC and Al interfaces have a better binding property. And, the fracture positions of C-terminated and Si-terminated interfaces are different in the process of stretching. Then, the distance variation in the process of stretching, the charge density differences, and the distribution of the electrons near the interface are analyzed. Al these work makes the specific reasons for the interface fracture are obtained at last. [ABSTRACT FROM AUTHOR]

Novel rutile TiO 2 @g-C 3 N 4 core-shell photocatalysts were synthesized by a facile saturated aqueous solution method. The composites were further characterized by using X-ray diffraction (XRD), high-resolution transmission microscopy (HRTEM), UV–visible light diffusion reflectance spectrometry (DRS), X-ray photoelectron spectroscopy (XPS) and so on. The results indicated that an ultrathin layer of g-C 3 N 4 was in-situ fabricated over the surface of rutile TiO 2 nanorod. The rutile TiO 2 @ g-C 3 N 4 core-shell structures showed much higher photo-current and photocatalytic activity for Rhodamine B (RhB) degradation under visible irradiation. The enhanced performance was attributed to the high separation efficiency of photo-induced carriers via a Z-scheme form. [ABSTRACT FROM AUTHOR]

In this communication, we present the results on YFe 0.9 Mn 0.1 O 3 (YFM10) ceramics processed by the sol–gel route in order to study Structural, dielectric and magnetic properties. XRD shows that this compound possesses an orthorhombic structure with Pbnm space group. Temperature dependence of magnetization [zero field cooled (ZFC) and field cooled (FC) behavior] and the M (H) behavior indicate that the Fe spins order antiferromagnetically with a weak ferromagnetic moment in YFM10, which may be attributed to the complex magnetic interaction between the Mn and Fe irons. Moreover, two dielectric relaxations were distinguished by the combination of impedance and modulus analysis for the YFM10 ceramics, which could be associated with the migration of oxygen vacancies and the carrier hopping process between Fe 2+ and Fe 3+ . [ABSTRACT FROM AUTHOR]

The structural, dielectric, leakage current and ferroelectric properties of the SrTi 1+x O 3 (x = −0.06, −0.03, 0, 0.03 and 0.06) ceramics have been investigated. X-ray diffraction and Scanning electron microscope reveal the microstructure of the samples. The Sr/Ti ratio in STO ceramics effectively adjusts their dielectric and the dc leakage behavior. In addition, the room temperature ferroelectricity of the nonstoichiometric STO ceramics is successfully realized by P-E hysteresis loop measurement. It is found that the origins of ferroelectricity for the Ti-rich and Sr-rich STO ceramics are different and may be related to the lattice distortions, the polar nanoregions and antisite-like defects with net local dipoles. [ABSTRACT FROM AUTHOR]

Pr-Fe co-doped SrTiO 3 films are prepared by the metal organic deposition method on (111) Pt/Ti/SiO 2 /Si substrates. Their dielectric and electric modulus behaviors are investigated in the temperature range of 30–500 °C with different measuring frequency of 10 2 ∼10 6 Hz. A typical ferroelectric relaxation phase transition is shown and its location shifts to the low temperature with the increase of Fe content. The imaginary parts of electric modulus M ″ exhibits the variable relaxation process with different Fe content, which is relation with OVs, PNRs and phase transition, and the possible causes of relaxation behavior dependence are analyzed in detail. [ABSTRACT FROM AUTHOR]

Density functional theory calculations were carried out to investigate the Diels-Alder cycloaddition between cyclopentadiene and C60 after the encapsulation of Li+ ion with transition states identified and confirmed by intrinsic reaction coordinate calculations. Our results showed that the Li+-encapsulation results in a lower energy barrier and the presence of counter anion [ABSTRACT FROM AUTHOR]

In this communication, we present the results on YFeO 3 and YFe 0.8 Mn 0.2 O 3 ceramics processed by the sol–gel route in order to study crystalline structure, dielectric properties. X-ray diffraction shows that this compound possesses an orthorhombic structure with Pbnm space group. Meanwhile, the dielectric properties of the samples were evaluated over broad temperature and frequency ranges. Two and three dielectric relaxations were distinguished by the combination of impedance and modulus analysis for the YFeO 3 and YFe 0.8 Mn 0.2 O 3 ceramics, which could be associated with the migration of oxygen vacancies and the carrier hopping process between Fe 2+ and Fe 3+ . [ABSTRACT FROM AUTHOR]

Effects of protein polari sation on docking accuracy were investigated using molecular docking programme AutoDock 4 in which topology-specific empirical Gasteiger charges were replaced with Polarised protein-specific charges (PPC) to represent quantum mechanics- polarised protein. Docking was successfully conducted for 50 diverse protein–ligand complexes. The docking with PPC charges shows a decrease in the root-mean-square deviation (RMSD) values of ligands compared to those from the docking with Gasteiger charges. Ligand binding orientations and their key interactions such as hydrogen bonding interactions in X-ray structures were substantially reproduced in complexes docked using PPC scheme with 98% of the RMSDs of the best docking poses less than 2 Å compared to 74% in the docking with Gasteiger charges. Considerable improvements in docking accuracy were observed by simply altering the atomic partial charges in the scoring function, which reflects the importance of protein polarisation in molecular docking. Further research can be carried out to (1) include polarisation of both ligands and proteins to account for polarisation effects within protein and between protein and ligand, and (2) develop a PPC-based scoring function to increase the docking accuracies for protein–ligand complexes from a larger variety of protein families. [ABSTRACT FROM AUTHOR]

The tunneling junction between one-dimensional topological superconductor and integer (fractional) topological insulator (TI), realized via point contact, is investigated theoretically with bosonization technology and renormalization group methods. For the integer TI case, in a finite range of edge interaction parameter, there is a non-trivial stable fixed point which corresponds to the physical picture that the edge of TI breaks up into two sections at the junction, with one side coupling strongly to the Majorana fermion and exhibiting perfect Andreev reflection, while the other side decouples, exhibiting perfect normal reflection at low energies. This fixed point can be used as a signature of the Majorana fermion and tested by nowadays experiment techniques. For the fractional TI case, the universal low-energy transport properties are described by perfect normal reflection, perfect Andreev reflection, or perfect insulating fixed points dependent on the filling fraction and edge interaction parameter of fractional TI. [ABSTRACT FROM AUTHOR]

Van der Waals (vdW) interactions play an important role on semiconductors in nanoscale. Here, we utilized first-principles calculations based on density functional theory to demonstrate the growth mode transition from prolate to multiunit configurations for Ge n ( n = 10-50) clusters. In agreement with the injected ion drift tube techniques that 'clusters with n < 70 can be thought of as loosely bound assemblies of small strongly bound fragments (such as Ge7 and Ge10),' we found these stable fragments are connected by Ge6, Ge9, or Ge10 unit (from bulk diamond), via strong covalent bonds. Our calculated cations usually fragment to Ge7 and Ge10 clusters, in accordance with the experiment results that the spectra Ge7 and Ge10 correspond to the mass abundance spectra. By controlling a germanium cluster with vdW interactions parameters in the program or not, we found that the vdW effects strengthen the covalent bond from different units more strikingly than that in a single unit. With more bonds between units than the threadlike structures, the multiunit structures have larger vdW energies, explaining why the isolated nanowires are harder to produce. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Both undoped and Pr-doped STO films are fabricated on (1 1 1) Pt/Ti/SiO 2 /Si by metal organic deposition. The influence of Pr dopant on oxygen vacancies is studied using X-ray photoelectron spectroscopy and X-ray diffraction. It is found that the concentration of oxygen vacancies is not decreases with the increase of the content of higher valence Pr ions, but decreases and increases alternatively. These results are associated with the variable valence and doping position of Pr ions, and the possible causes of which are discussed. [ABSTRACT FROM AUTHOR]

We propose an innovative approach based on optical vortex metrology (OVM) to characterize a dynamic random process. The dynamic process under consideration involves scatterers within a sample moving stochastically with time evolution. Specifically, the dynamic random process such as white paint drying has been investigated experimentally. In simulations, two unique descriptors, namely the successive survival rate of optical vortices and the average velocity of survival vortices, are introduced to determine the dynamic process based on the uniqueness of the optical vortex. Numerical simulation and experimental results show that these unique descriptors can be used to quantitatively analyze the dynamic process. Furthermore, we have found that further information on the dynamic process can be obtained by the proposed method, thereby facilitating innovative applications using OVM. [ABSTRACT FROM AUTHOR]

Abstract: A novel double-image encryption algorithm is proposed by using chaos-based local pixel scrambling technique and gyrator transform. Two original images are first regarded as the amplitude and phase of a complex function. Arnold transform is used to scramble pixels at a local area of the complex function, where the position of the scrambled area and the Arnold transform frequency are generated by the standard map and logistic map respectively. Then the changed complex function is converted by gyrator transform. The two operations mentioned will be implemented iteratively. The system parameters in local pixel scrambling and gyrator transform serve as the keys of this encryption algorithm. Numerical simulation has been performed to test the validity and the security of the proposed encryption algorithm. [Copyright &y& Elsevier]

Abstract: Both multilayered and homogeneous BST films with the same ratio of Ba to Sr are prepared by metal-organic deposition on (111) Pt/Ti/SiO2/Si substrates. X-ray diffraction reveals the microstructure of the samples. Compared with the homogeneous BST film, the multilayered BST film shows improved electrical properties with smaller leakage current, larger dielectric constant, higher tunability and better ferroelectrity. These results are associated with the multilayered structure and strain-related interactions between layers, and the possible causes of which are discussed. [Copyright &y& Elsevier]

A gold metallic grating fabricated onto magnetostrictive material (Tb 0.3 Dy 0.7 Fe 2.0 ) and its application to current sensing has been proposed. The gold metallic grating is fabricated to a Λ = 220 nm by using a focused ion beam (FIB) method and the metallic grating has integrated structure onto Tb 0.3 Dy 0.7 Fe 2.0 . Silica gel has good flexibility and it is using as wavelength layer between the gold metallic grating and gold layer on the Tb 0.3 Dy 0.7 Fe 2.0 . The metallic grating is placed in direct current solenoid and measured the reflection spectrum of the structure through fiber, and it causes a rapid and reversible response in wavelength shift in the visible wavelengths. This pronounced response introduces a novel current detection scheme. [ABSTRACT FROM AUTHOR]

YMn 1.07 O 3 ceramics were prepared by a sol–gel method, and the effect of Mn-excess on structure and dielectric properties was investigated. The X-ray diffraction pattern (XRD) shows that the sample has the hexagonal structure with space group P6 3 cm. It is found to suppresses ferroelectric ordering and enhance antiferromagnetic ordering compared with YMnO 3 . Moreover, two dielectric relaxations were observed for the low and high temperature relaxations, respectively, which are considered to be associated with local dipole moments and the oxygen vacancies. [ABSTRACT FROM AUTHOR]

Abstract: A core-shell structure material, carbon fiber/SnO2 was prepared by a surface modification precipitation process in aqueous solution. Results indicated that coating was obtained with 250nm-thick SnO2 shell on the surface of carbon fiber from 0.05M SnCl2. Optical properties of the composites were also investigated by photoluminescence (PL) spectroscopy. It was found that there is a broad yellow emission band centered at 583nm in the wavelength ranging from 450 to 700nm. Moreover, combining with the PL spectrum annealed in air, the broad yellow emission band may be attributed to the oxygen vacancies, which is supported by results from Raman study. [Copyright &y& Elsevier]

Abstract: Delineation of defects in the heavily doped n-type Czochralski silicon wafers by preferential etching is an issue not having been essentially solved. Herein, a chromium-free etchant based on HNO3–HF–H2O system, with an optimum volume ratio of , has been developed. It can reveal well the defects such as dislocation and oxygen precipitation-induced bulk microdefects (BMDs) in the heavily doped n-type silicon wafers with resistivities even lower than 1mΩcm. Moreover, this etchant is appropriate to delineate the defects on (111), (110) or (100) surface of silicon crystal. Furthermore, the density of oxygen precipitation-induced BMDs in the heavily doped n-type silicon wafers derived from the preferential etching using this newly developed etchant correlates well with that derived from scanning infrared microscopy (SIRM) within its detection limit. [Copyright &y& Elsevier]

Abstract: Grown-in distribution and annealing behavior of crystal-originated particles (COPs) in Czochralski silicon (Cz-Si) wafer with germanium doping have been investigated. It was found that COPs with high density but small sizes were inclined to generate in germanium-doped Cz-Si (GCz-Si) wafer. The increase of boron atoms in Cz-Si crystal with the germanium doping could benefit the formation of COPs while the oxygen interstitials in GCz-Si wafer could enhance the generation of COPs with small sizes. Meanwhile, it was suggested that the germanium doping in Cz-Si would result in the poor thermal stability of COPs. It is proposed that the combination between germanium atom and vacancy could reduce the free vacancy concentration and the onset temperature for void generation, thus forming denser but smaller void. While the stress compensation induced by boron and germanium atoms could increase the vacancy fluxes in heavy-boron doped GCz-Si crystal, the presence of oxygen atom in GCz-Si would incline to benefit the formation of inner oxide walls of void, especially with small sizes. Furthermore, thinner oxide walls within void for GCz-Si crystal are considered to be charged for the easy annihilation by the germanium doping. [Copyright &y& Elsevier]

Abstract: With the reduction in size of the features of ultra large-scale integrated (ULSI) circuits, micro-defects such as voids in Czochralski (Cz) silicon (Si) crystals play more important roles in the reliability and yield of these devices. As one of the tetravalent atoms, the behavior of germanium (Ge) doped in Cz Si crystals has attracted considerable attention in recent years. In this presentation, recent processes in the study of voids in Ge doped Cz (GCZ) Si crystals are reviewed. The grown-in characteristics of voids in GCZ wafer, including flow pattern defects (FPDs) and crystal originated particles (COPs), suggested that Ge can suppress large voids resulting in denser and smaller voids. Meanwhile, it has been found that the density of voids can be decreased by Ge doping and they can be eliminated easily in GCZ Si crystals through high temperature annealing. It is therefore speculated that the gate oxide integrity (GOI) of semiconductor devices can be improved by Ge doping. The mechanism of the effect of Ge on voids is discussed to explain the experimental results. [Copyright &y& Elsevier]

Abstract: The growth of p/p+ silicon epitaxial silicon wafers (epi-wafers) without misfit dislocations has been successfully achieved by using heavily boron-doped Czochralski (CZ) silicon wafers codoped with desirable level of germanium as the substrates. The lattice compensation by codoping of germanium and boron into the silicon matrix to reduce the lattice mismatch between the substrate (heavily boron-doped) and epi-layer (lightly boron-doped) is the basic idea underlying in the present achievement. In principle, the codoping of germanium and boron in the CZ silicon can be tailored to achieve misfit dislocation-free epi-layer with required thickness. It is reasonably expected that the presented solution to elimination of misfit dislocations in the p/p+ silicon wafers can be applied in the volume production. [Copyright &y& Elsevier]

Abstract: Denuded zone (DZ) formed by rapid thermal process (RTP) followed with the low–high (Lo–Hi) annealing in nitrogen-doped Czochralski (NCZ) silicon wafer was studied in this paper. In comparison with the conventional CZ silicon, the DZ in NCZ silicon was a little narrower, while the bulk microdefects were much denser, as a result of nitrogen-enhanced oxygen precipitation. It was also found that DZs within CZ and NCZ silicon wafers shrunk notably when further subjected to rigorous oxygen precipitation annealing, however, a width of substantial DZ remained within either wafer. Furthermore, it is definitely proved that the nitrogen doping does not affect the formation of defect-free DZ by the RTP-based internal gettering (IG) process. [Copyright &y& Elsevier]

The effect of nitrogen doping on the minority carrier lifetime in Czochralski silicon (CZ-Si) passivated in dry O2 at different temperatures was studied. It was found that the most effective passivation temperature of nitrogen-doped CZ silicon (NCZ-Si) wafers was 1000 °C, the same as that of CZ-Si wafers, but the most effective passivation time was 0.5 h, which is shorter than that of CZ-Si wafers (1 h). Furthermore, with increasing anneal time, the minority carrier lifetime of NCZ-Si decreased more quickly than that of CZ-Si, while interstitial oxygen in NCZ-Si precipitated more heavily. The experiments also showed that, during two-step (650 °C+1050 °C) annealing, the minority carrier lifetime of NCZ-Si decreased significantly due to oxygen precipitation. It can be concluded that the crystal quality of as-grown NCZ-Si is similar to that of as-grown CZ-Si, however the minority carrier lifetime of NCZ-Si decreased more rapidly than that of CZ-Si during thermal cycles because of nitrogen enhancing oxygen precipitates. [Copyright &y& Elsevier]

The effect of oxygen precipitation on flow pattern defects (FPDs) relative to voids in bulk silicon was investigated. FPDs and voids were measured after different annealing time, and with various interstitial oxygen contents and bulk stacking faults (BSFs). It was found that, during annealing, interstitial oxygen in bulk silicon precipitated, however the FPDs density remained constant. The density of BSFs increased with annealing time at 1100 °C. After annealing, the morphology of voids was found to be octahedral with the oxide films inside them, the same as as-grown samples. Therefore, it is concluded that the interstitial silicon atoms released during oxygen precipitation did not enter the voids because of the resistance of the oxide films inside the voids, but condensed into stacking faults. The dissolution of the oxide films is believed to be the principal cause for the annihilation of voids. [Copyright &y& Elsevier]

The intrinsic gettering (IG) of germanium-doped Czochralski (GCZ) silicon with different concentrations of germanium has been investigated in this paper. The conventional Czochralski (CZ) and the GCZ silicon samples were annealed using a one-step high temperature process followed by a sequence of low–high temperature annealing cycles. It was found that the good defect-free denude zones in the near surface of the GCZ silicon could be achieved using simply a one-step high temperature annealing process. Furthermore, the density of bulk microdefects as IG sites was higher than that in the CZ silicon, as a result of germanium enhancing oxygen precipitation during three-step annealing. Meanwhile, the experimental results showed that germanium also enhanced the out-diffusion of oxygen. Furthermore, it is believed that germanium doping can increase the ability of IG in CZ silicon wafers. [Copyright &y& Elsevier]

The effect of germanium (Ge) on void defects in lightly Ge-doped Czochralski (GCZ) silicon (Si) crystals has been investigated. Three GCZ Si crystals with different Ge concentrations (1015–1018 cm−3) and one conventional Czochralski (CZ) Si crystal were grown under almost the same growth conditions. It is found that the density of flow pattern defects (FPDs) related to void defects in the as-grown GCZ Si decreases with the increase of Ge concentration. The voids in the GCZ Si could be eliminated more easily during annealing at the high temperatures of 1050–1200°C. It is concluded that Ge can suppress the formation of voids during Si crystal growth. Thus, GCZ Si can be expected to use widely in modern microelectronic industry. [Copyright &y& Elsevier]

Metal-support interactions have been explored as an effective method to improve the photocatalytic activity in heterogeneous catalysis. In this study, first-principles calculations confirmed that H 2 O can be split on Ru 8 cluster decorated anatase TiO 2 (101) surface (denoted as Ru 8 /TiO 2 (101)), whose adsorption energy (E ads) and energy barrier (E b) are lower than H 2 O on isolated Ru 8 cluster, due to significant charge transfer from Ru 8 cluster to TiO 2 (101). Compared with Ru 8 /TiO 2 (101), single Ru atom decorated TiO 2 (101) has higher E ads with H 2 O, manifesting better catalytic property. The similar dissociation process of H 2 O on isolated Ru 8 cluster and Ru 8 /TiO 2 (101) indicated that we can study the molecule/cluster in detail firstly, and then apply it to molecule/cluster/surface, which will save much computing resource. • The adsorption energy and splitting energy barrier for H 2 O on Ru 8 /TiO 2 (101) are lower than H 2 O on isolated Ru 8 cluster. • Compared with Ru 8 /TiO 2 (101), Ru 1 /TiO 2 (101) has higher E ads with H 2 O, manifesting better catalytic property. • The dissociation process of H 2 O on isolated Ru 8 cluster and Ru 8 /TiO 2 (101) is similar. • The study builds a bridge on catalysis science between cluster/surface in experiment and isolated cluster in theory. [ABSTRACT FROM AUTHOR]

In the present work we analyze the structural and magnetic properties of YFe 0.8 Mn 0.2 O 3 ceramics. Using the X-ray diffraction pattern, it was found that the sample has an orthorhombic structure in space group Pbnm . Temperature dependence of magnetization with different fields (200 Oe, 1000 Oe and 5000 Oe) reveal the existence of spin glass like behavior. Moreover, the magnetic hysteresis loops further confirm the spin glass feature of YFe 0.8 Mn 0.2 O 3 , which may be caused by competition between the ferromagnetic and antiferromagnetic interaction. [ABSTRACT FROM AUTHOR]

Abstract: Bi doped TbMnO3 ceramics have been synthesized by solid state reaction, and the effect of substitution in TbMnO3 on the structural, magnetic and dielectric properties is investigated. The X-ray diffraction pattern shows that the samples have an orthorhombic structure. The Bi substitution is found to suppresses the Tb-spin ordering point (T Tb) and ferroelectric ordering point (T C), which attributed to the strength reduction in the exchange interactions J Tb–Tb and J Mn–Tb. In addition, a dielectric relaxation with an activation energy of ~20meV is observed at low temperature in Tb1−x Bi x MnO3, and the relaxorlike dielectric characteristics may be attributed to the dipolar effects induced by charge carrier hopping motions. [Copyright &y& Elsevier]

Highlights: [•] Mn-doped Ba0.6Sr0.4TiO3 films (Mn 10%) were prepared by MOD. [•] Mn dopant improves the dc leakage behavior and dielectric loss of the BST films. [•] The study provides another approach for adjusting material properties. [Copyright &y& Elsevier]