bluuebunny/crossref_metadata_2025 huggingface dataset:
Spin-dependent gradient correction for more accurate atomization energies of molecules
Authors: Constantin Lucian A. , Fabiano Eduardo , Sala Fabio Della
Published: November 2012

We discuss, simplify, and improve the spin-dependent correction of Constantin et al. [Phys. Rev. B 84, 233103 (2011)10.1103/PhysRevB.84.233103] for atomization energies, and develop a density parameter of the form v∝|∇n|/n10/9, found from the statistical ensemble of one-electron densities. The here constructed exchange-correlation generalized gradient approximations (GGAs), named zvPBEsol and zvPBEint, show a broad applicability, and a good accuracy for many applications, because these corrected functionals significantly improve the atomization and binding energies of molecular systems, without worsening the behavior of the original functionals (PBEsol and PBEint) for other properties. This spin-dependent correction is also applied to meta-GGA dynamical correlation functionals combined with exact-exchange; in this case a significant (about 30%) improvement in atomization energies of small molecules is found.
Theoretical prediction on the structures and stability of the noble-gas containing anions FNgCC− (Ng=He, Ar, Kr, and Xe)
Authors: Peng Chia-Yu , Yang Chang-Yu , Sun Yi-Lun , Hu Wei-Ping
Published: November 2012

We have made high-level theoretical study on a new type of noble-gas (Ng) containing anions FNgCC−. The calculated short Ng−CC bond lengths of 1.13, 1.77, 1.89, and 2.04 Å for Ng=He, Ar, Kr, and Xe, respectively, and the electron density distributions indicated strong covalent interactions between the Ng and CC induced by the polarizing fluoride ion. Except for FHeCC−, the structures of all other FNgCC− were predicted to be linear. The intrinsic stability of the FNgCC− was studied by calculating the energies of the three-body dissociation reaction: FNgCC− → F− + Ng + CC and by calculating the energy barriers of the two-body dissociation reaction: FNgCC− → Ng + FCC−. The results showed that FNgCC− (Ng=Ar, Kr, Xe) could be kinetically stable in the gas phase with the three-body dissociation energies of 17, 37, and 64 kcal/mol and two body-dissociation barriers of 22, 31, and 42 kcal/mol, respectively, at the coupled-cluster single double (triple)/aug-cc-pVQZ level of theory. The structures and the stability were also confirmed using the multi-reference CASPT2 calculation. Future experimental identification of the FNgCC− anions is expected under cryogenic conditions.
Explicit system-bath correlation calculated using the hierarchical equations of motion method
Authors: Zhu Lili , Liu Hao , Xie Weiwei , Shi Qiang
Published: November 2012

The hierarchical equations of motion (HEOM) method has recently been widely applied to many problems of quantum dynamics in condensed phase. It is now well known that the auxiliary density operators (ADOs) in the HEOM formalism contain system-bath correlations that are important in calculating various dynamical properties, yet quantitative relations to explicitly calculate such correlations from the ADOs are still scarce. This paper extends a previous study [Q. Shi et al., J. Chem. Phys. 130, 164518 (2009)10.1063/1.3125003] in investigating the physical meaning of ADOs to general spectral densities and lower temperature cases. Using the path-integral technique, we derive exact relations between the expectation values of the collective bath coordinate and the ADOs, which could be very useful in investigating the correlated system-bath dynamics directly with the HEOM formalism. Numerical examples concerning the evolution of the expectation values of the collective bath coordinate are also presented.
Plasmon resonances in linear noble-metal chains
Authors: Gao Bin , Ruud Kenneth , Luo Yi
Published: November 2012

The electronic excitations of three noble-metall chains—copper, silver, and gold—have been investigated at the time-dependent density functional theory level. The reduced single-electron density matrix is propagated according to the Liouville-von Neumann equation in the real-time domain after an impulse excitation. The propagation in the real-time domain enables us to investigate the formation and size evolution of electronic excitations in these metallic chains with different number of atoms, up to a total of 26 atoms. The longitudinal oscillations at lower excitation energies are dominated by s → p transitions in these chains and have collective or central resonances, while the first peak involving d → p transitions in the longitudinal mode appears at a higher excitation energy and shows collective resonances. In the transverse oscillations, there are in most cases d → p transitions in each resonance, which can be attributed to either central or end resonances. Convergence of the oscillations, in particular those involving the collective and central resonances in the three noble-metal chains can only be observed for chains with 18 atoms or more. Different spectroscopic characteristics among these three metallic chains can be attributed to their different electronic structures, in particular the relativistic effects in the gold chains have a dramatic effect on their electronic structures and excitations.
The critical current density in superconducting cylinder with different cross sections
Authors: Yong Huadong , Jing Ze , Zhou Youhe
Published: November 2012

This paper studies the transport critical current density in a superconducting cylinder with a hole and a superconducting elliptic cylinder. Based on the Maxwell's equation, the critical current densities are obtained with numerical method for different cross sections. In order to determine the main features of different cross sections, the average critical current density and magnetic field are considered. It is shown that the average critical current density is affected by the geometry and size of the cross section. The average critical current density is a monotonic function of the radius in the superconducting cylinder with a hole. However, the average critical current density in the superconducting elliptic cylinder decreases with major axis first and then increases.
Study of electron transport characteristics through self-aligned Si-based quantum dots
Authors: Makihara Katsunori , Ikeda Mitsuhisa , Miyazaki Seiichi
Published: November 2012

Self-aligned Si-based quantum dots (QDs) with an ultra-thin oxide interlayer were spontaneously formed on ∼1.0-nm-thick thermally grown SiO2/Si(100) by a process sequence that consists of Si-QDs formation by controlling low-pressure chemical vapor deposition (LPCVD) using pure Si2H6, selective Ge-LPCVD, thermal oxidation of the dots, thermal desorption of Ge oxide, and subsequent formation of the Si-QDs. After formation of Al back electrode, electron transport properties through the aligned dots structures so-prepared were characterized by employing atomic force microscopy with a conductive cantilever. The tunneling current through the aligned dots exhibited a clear current bump and negative differential conductance at room temperature with a peak current to valley ratio as high as 100 at around the resonance voltage as a result of resonant tunneling mediated by the quantized energy levels of the dots.
Limiting efficiency of generalized realistic c-Si solar cells coupled to ideal up-converters
Authors: Johnson Craig M. , Conibeer Gavin J.
Published: November 2012

The detailed balance model of photovoltaic up-conversion is revised for the specific case of a c-Si solar cell under the AM1.5G solar spectrum. The limiting efficiency of an ideal solar cell with a band gap of 1.117 eV may be increased from approximately 33% to 40% with ideal up-conversion. However, real solar cells do not demonstrate the step-function absorption characteristic assumed in the standard detailed balance model. Here, we use tabulated Si refractive index data to develop a generalized model of a realistic conventional c-Si solar cell. The model incorporates optical design and material parameters such as free carrier absorption that have a non-trivial impact on the operation of the up-conversion layer. While these modifications are shown to decrease the absolute limiting efficiency, the benefit of up-conversion is shown to be relatively greater.
Thermal rectification reversal in carbon nanotubes
Authors: Loh G. C. , Teo E. H. T. , Tay B. K.
Published: November 2012

In principle, rectifying phonon and electron flows appear similar, whereby more energy is transported in one direction than the opposite one. However, their physical mechanisms are inherently different. By using molecular dynamics simulations, this study reports on a few interesting aspects of thermal rectification in carbon nanotubes: (1) The dependence of the rectification ratio on the structural symmetry (represented by the position of vacancy clusters) of the nanotube and more importantly (2) a reversal in the rectifying direction as the normalized temperature difference of the heat baths is increased. The flux-mediated diffuse mismatch model is extended to explain the reversal phenomenon—initially with a simplifying assumption that the transmission coefficients at the vacancy/scatterer are identical in bidirectional phonon transport, and then with a moderating factor to distinguish between both coefficients. It is noted that in both cases, the conditions for thermal rectification reversal are attainable and thus explain the results of the simulations.
Electrical impedance dependence on the direct and converse magnetoelectric resonances in magnetostrictive/piezoelectric laminated composites
Authors: Wu Zheng , Xiang Zhihui , Jia Yanmin , Zhang Yihe , Luo Haosu
Published: November 2012

We fabricated two kinds of sandwiched magnetostrictive/piezoelectric composite and studied their magnetoelectric and electrical impedance properties. It was found that the electrical impedance resonance (fr) and anti-resonance (fanti−r) frequencies were, respectively, corresponded to the converse and direct magnetoelectric resonance ones. An equivalent circuit was developed to explain this phenomenon. The experimental result may be helpful in designing the magnetoelectric transducers.
Trimethyl-aluminum and ozone interactions with graphite in atomic layer deposition of Al2O3
Authors: McDonnell Stephen , Pirkle Adam , Kim Jiyoung , Colombo Luigi , Wallace Robert M.
Published: November 2012

A study of the chemical interactions between the atomic layer deposition (ALD) Al2O3 precursors trimethlyaluminum (TMA) and ozone (TMA/O3) and sp2 carbon surfaces is presented. In-situ x-ray photoelectron spectroscopy is used to study these interactions, while ex-situ atomic force microscopy (AFM) is used to monitor the surface morphology. Ozone functionalization of the sp2 carbon surface is discussed and the dependence of TMA/O3 reactions over a range of ALD process conditions is examined. The utilization of a 6-cycle room temperature TMA/O3 ALD seed layer to nucleate the conformal growth of Al2O3 by TMA/H2O at 200 °C as well as the quality of such films is discussed. Two stages of ozone reactions are observed: first the ozone appears to remove adsorbed species from the graphite surface before reacting with the surface. The deposition of Al2O3 is found to be strongly dependant on the N2 purge time as well as the precursor pulse sequence. It is shown that the quality of these low temperature deposited films can easily be improved by removal of carbon containing species through an 300 °C anneal.
Thermo-optical properties of embedded silver nanoparticles
Authors: Rashidi Huyeh M. , Shirdel Havar M. , Palpant B.
Published: November 2012

Thermo-optical properties of nanocomposite materials consisting of noble metal nanoparticles dispersed in a dielectric medium are appropriate for many applications as imaging, nonlinear optics, or optical monitoring of local thermal exchanges. Here, we analyze the thermo-optical response of silver nanoparticles. The contribution of inter- and intraband transitions to the thermo-optical index of bulk silver is first extracted using experimental results reported earlier in the literature. The influence of these two contributions on the thermo-optical properties of silver nanoparticles embedded in glass is then investigated. The results show that these properties are essentially due to the intraband thermo-optical contribution in the vicinity of the surface plasmon resonance of the nanoparticles, while they are dominated by the interband contribution close to the interband transition threshold.
Optimal diabatic states based on solvation parameters
Authors: Alguire Ethan , Subotnik Joseph E.
Published: November 2012

A new method for obtaining diabatic electronic states of a molecular system in a condensed environment is proposed and evaluated. This technique, which we denote as Edmiston-Ruedenberg (ER)-ɛ diabatization, forms diabatic states as a linear combination of adiabatic states by minimizing an approximation to the total coupling between states in a medium with temperature T and with a characteristic Pekar factor C. ER-ɛ diabatization represents an improvement upon previous localized diabatization methods for two reasons: first, it is sensitive to the energy separation between adiabatic states, thus accounting for fluctuations in energy and effectively preventing over-mixing. Second, it responds to the strength of system-solvent interactions via parameters for the dielectric constant and temperature of the medium, which is physically reasonable. Here, we apply the ER-ɛ technique to both intramolecular and intermolecular excitation energy transfer systems. We find that ER-ɛ diabatic states satisfy three important properties: (1) they have small derivative couplings everywhere; (2) they have small diabatic couplings at avoided crossings, and (3) they have negligible diabatic couplings everywhere else. As such, ER-ɛ states are good candidates for so-called “optimal diabatic states.”
Observation of quantum Talbot effect from a domain-engineered nonlinear photonic crystal
Authors: Jin H. , Xu P. , Zhao J. S. , Leng H. Y. , Zhong M. L. , Zhu S. N.
Published: November 2012

The quantum Talbot effect is observed from a domain-engineered nonlinear photonic crystal dispensing with a real grating. We deduce and experimentally verify the quantum self-imaging formula which is related to the crystal's structure parameter and working wavelengths. A two-photon Talbot carpet is captured to characterize the Fresnel diffraction dynamics of entangled photons wherein the quantum fractional Talbot effect is specified. The compact and stable quantum Talbot effect can be considered as the contactless diagnosis of domain's homogeneity and developed for new types of entangled photon source and quantum technologies such as quantum lithography with improved performance.
Fabrication and characterization of the gapless half-Heusler YPtSb thin films
Authors: Wang Wenhong , Du Yin , Liu Enke , Liu Zhongyuan , Wu G. H.
Published: November 2012

Half-Heusler YPtSb thin films were fabricated by magnetron co-sputtering method on MgO-buffered SiO2/Si(001) substrates. X-ray diffraction pattern and energy dispersive X-ray spectroscopy confirmed the high-quality growth and stoichiometry. The temperature dependence of the resistivity shows a semiconducting-type behavior down to low temperature. The Hall mobility was determined to be 450 cm2/V s at 300 K, which is much higher than the bulk value (∼300 cm2/V s). In-plane magnetoresistance (MR) measurements with fields applied along and perpendicular to the current direction show opposite MR signs, which suggest the possible existence of the topological surface states.
First-principles study of the oxygen adsorption and dissociation on graphene and nitrogen doped graphene for Li-air batteries
Authors: Yan H. J. , Xu B. , Shi S. Q. , Ouyang C. Y.
Published: November 2012

Recently, Yoo and Zhou [ACS Nano 5, 3020–3026 (2011)] reported that graphene can be directly used as electrode for Li-air batteries, suggesting that graphene itself can be served as catalyst for O2 dissociation reaction. In this work, we show from density functional theory calculations that the O2 dissociation reaction energy barrier is substantially decreased on the graphene surface comparing to that of in vacuum. Furthermore, N-doping can further decrease the energy barrier from 2.39 eV (undoped case) to 1.20 eV. The O2 molecule physical adsorption, O atom chemical adsorption at the graphene, and N-doped graphene surfaces are also simulated.
Testing recent charge-on-spring type polarizable water models. I. Melting temperature and ice properties
Authors: Kiss Péter T. , Bertsyk Péter , Baranyai András
Published: November 2012

We determined the freezing point of eight molecular models of water. All models use the charge-on-spring (COS) method to express polarization. The studied models were the COS/G2, COS/G3 [H. Yu and W. F. van Gunsteren, J. Chem. Phys. 121, 9549 (2004)10.1063/1.1805516], the COS/B2 [H. Yu, T. Hansson, and W. F. van Gunsteren, J. Chem. Phys. 118, 221 (2003)10.1063/1.1523915], the SWM4-DP [G. Lamoureux, A. D. MacKerell, Jr., and B. Roux, J. Chem. Phys. 119, 5185 (2003)10.1063/1.1598191], the SWM4-NDP [G. Lamoureux, E. Harder, I. V. Vorobyov, B. Roux, and A. D. MacKerell, Jr., Chem. Phys. Lett. 418, 245 (2006)10.1016/j.cplett.2005.10.135], and three versions of our model, the BKd1, BKd2, and BKd3. The BKd1 is the original Gaussian model [P. T. Kiss, M. Darvas, A. Baranyai, and P. Jedlovszky, J. Chem. Phys. 136, 114706 (2012)10.1063/1.3692602] with constant polarization and with a simple exponential repulsion. The BKd2 applies field-dependent polarizability [A. Baranyai and P. T. Kiss, J. Chem. Phys. 135, 234110 (2011)10.1063/1.3670962], while the BKd3 model has variable size to approximate the temperature-density (T-ρ) curve of water [P. T. Kiss and A. Baranyai, J. Chem. Phys. 137, 084506 (2012)10.1063/1.4746419]. We used the thermodynamic integration (TI) and the Gibbs-Helmholtz equation to determine the equality of the free energy for liquid water and hexagonal ice (Ih) at 1 bar. We used the TIP4P and the SPC/E models as reference systems of the TI. The studied models severely underestimate the experimental melting point of ice Ih. The calculated freezing points of the models are the following: COS/G2, 215 K; COS/G3, 149 K; SWM4-DP, 186 K; BKd1, 207 K; BKd2, 213 K; BKd3, 233 K. The freezing temperature of the SWM4-NDP system is certainly below 120 K. It might even be that the water phase is more stable than the ice Ih at 1 bar in the full temperature range. The COS/B2 model melts below 100 K. The best result was obtained for the BKd3 model which indicates that correct description of the (T-ρ) curve improves the estimation of the freezing point. We also determined and compared the densities of high-pressure polymorphs of ice for these models.
Testing the recent charge-on-spring type polarizable water models. II. Vapor-liquid equilibrium
Authors: Kiss Péter T. , Baranyai András
Published: November 2012

We studied the vapor-liquid coexistence region of seven molecular models of water. All models use the charge-on-spring (COS) method to express polarization. The studied models were the COS/G2, COS/G3 [H. Yu and W. F. van Gunsteren, J. Chem. Phys. 121, 9549 (2004)10.1063/1.1805516], the SWM4-DP [G. Lamoureux, A. D. MacKerell, Jr., and B. Roux, J. Chem. Phys. 119, 5185 (2003)10.1063/1.1598191], the SWM4-NDP [G. Lamoureux, E. Harder, I. V. Vorobyov, B. Roux, and A. D. MacKerell, Jr., Chem. Phys. Lett. 418, 245 (2006)10.1016/j.cplett.2005.10.135], and three versions of our model, the BKd1, BKd2, and BKd3. The BKd1 is the original Gaussian model [P. T. Kiss, M. Darvas, A. Baranyai, and P. Jedlovszky, J. Chem. Phys. 136, 114706 (2012)10.1063/1.3692602] with constant polarization and with a simple exponential repulsion. The BKd2 applies field-dependent polarizability [A. Baranyai and P. T. Kiss, J. Chem. Phys. 135, 234110 (2011)10.1063/1.3670962], while the BKd3 model has variable size to approximate the temperature-density (T-ρ) curve of water [P. T. Kiss and A. Baranyai, J. Chem. Phys. 137, 194102 (2012)10.1063/1.4767063]. We calculated the second virial coefficient, the heat of vaporization, equilibrium vapor pressure, the vapor-liquid coexistence curve, and the surface tension in terms of the temperature. We determined and compared the critical temperatures, densities, and pressures of the models. We concluded that the high temperature slope of the (T-ρ) curve accurately predicts the critical temperature. We found that Gaussian charge distributions have clear advantages over the point charges describing the critical region. It is impossible to describe the vapor-liquid coexistence properties consistently with nonpolarizable models, even if their critical temperature is correct.
Growth mechanism of atomic layer deposited Al2O3 on GaAs(001)-4 × 6 surface with trimethylaluminum and water as precursors
Authors: Huang M. L. , Chang Y. H. , Lin T. D. , Lin H. Y. , Liu Y. T. , Pi T. W. , Hong M. , Kwo J.
Published: November 2012

A microscopic view of in situ atomic layer deposition Al2O3 on clean n-GaAs (001)-4 × 6 surfaces probed by high-resolution synchrotron radiation photoemission is presented. The precursors of trimethylaluminum (TMA) and water partially and selectively bond with the surface atoms without disturbing the atoms in the subsurface layer. The first-cycle TMA acts differently on the surface As atoms; namely, TMA is dissociative on As in the As-Ga dimer but is physisorbed on As that is 3-fold Ga coordinated. Water drastically alters the TMA-covered surface to etch off the dissociated TMA with As, giving Ga–O bonding for the later deposition of Al2O3 and at the same time to transform the configuration of the physisorbed TMA to bond strongly with As. Approximately six cycles of purges (TMA + water) are required before the interaction at the interface is complete. In comparison, the e-beam deposition of Al2O3 on GaAs greatly disturbs the III-V surface so that a high As 4+ charge state appears and the surface Ga atoms become clustered.
Post-fabrication control of evanescent tunnelling in photonic crystal molecules
Authors: Caselli N. , Intonti F. , Bianchi C. , Riboli F. , Vignolini S. , Balet L. , Li L. H. , Francardi M. , Gerardino A. , Fiore A. , Gurioli M.
Published: November 2012

The post-fabrication control of evanescent tunnelling in photonic crystal molecules is demonstrated through the combination of selective infiltration and oxidation. By laser non thermal oxidation, we reduce the photonic coupling by more than 30% while by means of water micro-infiltration, we increase it by 28%. Fine-tuning of the photonic coupling is achieved by low-power laser oxidation and forced evaporation, opening the route to post-fabrication control of array of coupled cavities.
Reconfigurable terahertz plasmonic antenna concept using a graphene stack
Authors: Tamagnone M. , Gómez-Díaz J. S. , Mosig J. R. , Perruisseau-Carrier J.
Published: November 2012

The concept and analysis of a terahertz (THz) frequency-reconfigurable antenna using graphene are presented. The antenna exploits dipole-like plasmonic resonances that can be frequency-tuned on large range via the electric field effect in a graphene stack. In addition to efficient dynamic control, the proposed approach allows high miniaturization and good direct matching with continuous wave THz sources. A qualitative model is used to explain the excellent impedance stability under reconfiguration. These initial results are very promising for future all-graphene THz transceivers and sensors.
Effect of retraction speed on adhesion of elastomer fibrillar structures
Authors: Abusomwan Uyiosa , Sitti Metin
Published: November 2012

We studied the dependence of adhesion on retraction speed in elastic fibrillar structures. The evolution of the real contact area and crack propagation speeds at the contact interface was characterized during retraction using a custom measurement system. The experimental results showed an increase in the average crack propagation speed and the rate of change of real contact area during pull-off, for increasing retraction speed. Our results indicate that during pull-off, the critical contact area does not have significant contribution to rate-dependent adhesion, whereas rate of change in the contact area and the crack propagation speed contribute significantly to rate-dependent adhesion.
Optical pulse compression on a silicon chip—Effect of group velocity dispersion and free carriers
Authors: Tan D. T. H.
Published: November 2012

The effect of group velocity dispersion and free carrier lifetime on pulse quality and nonlinear phase acquisition is studied in a two-stage pulse compressor on a silicon chip. Appropriately, designing the dispersion in the nonlinear medium enables compressed pulses with more than 90% of the pulse energy confined in the main lobe to be generated. Free carrier lifetime is observed to impact nonlinear phase acquisition in the single pulse regime. The pulse compression factor decreases monotonically as the pulse repetition rate increases. Conditions for efficient compression at high repetition rates in the absence of free carrier quenching techniques are discussed.
Nonlinear response of quantum cascade structures
Authors: Winge David O. , Lindskog Martin , Wacker Andreas
Published: November 2012

The gain spectrum of a terahertz quantum cascade laser is analyzed by a nonequilibrium Green's functions approach. Higher harmonics of the response function were retrievable, providing a way to approach nonlinear phenomena in quantum cascade lasers theoretically. Gain is simulated under operation conditions and results are presented both for linear response and strong laser fields. An iterative way of reconstructing the field strength inside the laser cavity at lasing conditions is described using a measured value of the level of the losses of the studied system. Comparison with recent experimental data from time-domain-spectroscopy indicates that the experimental situation is beyond linear response.
Photodissociation dynamics of methoxybenzoic acid at 193 nm
Authors: Ho Yu-Chieh , Dyakov Yuri A. , Hsu Wen-Hsin , Ni Chi-Kung , Sun Yi-Lun , Hu Wei-Ping
Published: November 2012

The theoretical prediction and experimental confirmation of the 1πσ* repulsive excited state along O−H bond of phenol have large impact on the interpretation of phenol and tyrosine photochemistry. In this work, we investigated the photodissociation dynamics of 2-, 3-, and 4-methoxybenzoic acid (MOBA) in a molecular beam at 193 nm using multimass ion imaging techniques. In addition, the ground state and the excited state potential energy surfaces of MOBA were investigated using ab initio calculations, and branching ratios were predicted by Rice–Ramsperger–Kassel–Marcus theory. The results show that (1) the excited state potential of 1πσ* along O−CH3 bond remains similar to that of phenol and anisole, (2) CH3 elimination is the major channel for three MOBA isomers, and (3) photofragment translational energy distributions show bimodal distributions, representing the dissociation on the ground state and repulsive excited state, respectively. Comparison to the study of hydroxbenzoic acid [Y. L. Yang, Y. A. Dyakov, Y. T. Lee, C. K. Ni, Y. L. Sun, and W. P. Hu, J. Chem. Phys. 134, 034314 (2011)10.1063/1.3526059] shows that only the intramolecular hydrogen bonding has significant effects on the excited state dynamics of phenol chromophores.
Magnetoelectric coupling in La0.6Ca0.4MnO3-Bi0.6Nd0.4TiO3 composite thin films derived by a chemical solution deposition method
Authors: Cheng C. P. , Tang M. H. , Lv X. S. , Tang Z. H. , Xiao Y. G.
Published: November 2012

Magnetoelectric (ME) xLa0.6Ca0.4MnO3-(1−x)Bi0.6Nd0.4TiO3 composite thin films with x = 0.3, 0.4, and 0.5 were fabricated on Pt/Ti/SiO2/Si(100) substrates by a chemical solution deposition method. The well-defined ferroelectric loops are observed. The Pr values are 11.2, 12.8, and 13.9 μC/cm2 under the condition of about 350 kV/cm electric field for the composite films with x = 0.3, 0.4, and 0.5. The composite films exhibit typical magnetic hysteresis loops, as well as remnant magnetizations. ME effect which is dependent on Hbias is observed. The results show that the films exhibit both good ferroelectric and magnetic properties, as well as a ME effect.
Coexistence of conventional and inverse magnetocaloric effects and critical behaviors in Ni50Mn50−xSnx (x = 13 and 14) alloy ribbons
Authors: Phan The-Long , Zhang P. , Dan N. H. , Yen N. H. , Thanh P. T. , Thanh T. D. , Phan M. H. , Yu S. C.
Published: November 2012

A systematic study of the conventional and inverse magnetocaloric effects and critical behaviors in Ni50Mn50−xSnx (x = 13 and 14) alloy ribbons has been performed. We show that although the magnetic entropy change around the second-order ferromagnetic-paramagnetic (FM-PM) transition (ΔSm ≈ −4 J/kg K) in the austenitic phase is about five times smaller than that around the first-order martensitic-austenitic (M-A) transformation (ΔSm ≈ 22 J/kg K), the refrigerant capacity (RC) – an important figure of merit – is about two times larger for the former case (RC ≈ 160 J/kg) than for the latter case (RC ≈ 75 J/kg). This finding points to an important fact that to assess the usefulness of a magnetocaloric material, one should not only consider ΔSm but also must evaluate both ΔSm and RC. Our critical analysis near the second-order FM-PM transition reveals that Sn addition tends to drive the system, in the austenitic FM phase, from the short-range (x = 13) to long-range (x = 14) FM order.
Application of in-cell touch sensor using photo-leakage current in dual gate a-InGaZnO thin-film transistors
Authors: Hsieh Tien-Yu , Chang Ting-Chang , Chen Te-Chih , Chen Yu-Chun , Chen Yu-Te , Liao Po-Yung , Chu Ann-Kuo , Tsai Wu-Wei , Chiang Wen-Jen , Yan Jing-Yi
Published: November 2012

In-cell touch sensor that can be integrated with display pixel circuit using dual gate InGaZnO thin-film transistor is proposed. Under bottom gate operation, device characteristics are not sensitive to light illumination. On the contrary, light can lead to evident subthreshold leakage when operated with top gate. This behavior allows touch sensor to be realized by sensing the ambient light using top gate operation, without affecting normal bottom gate operated devices in display pixel. Further, the proposed operation method of touch sensor needs no additional fabrication and cost, and even black matrix is not required either.
Diffusion-induced stresses of electrode nanomaterials in lithium-ion battery: The effects of surface stress
Authors: Hao Feng , Gao Xiang , Fang Daining
Published: November 2012

Nanomaterials offer large reaction surfaces making for high-rate lithium-ion transfer and fewer constraints to avoid fracture. Nevertheless, surface effect arises inevitably due to so high surface-to-volume ratio. Accordingly, the fundamental framework of surface stress is involved to study diffusion-induced stresses within electrode nanoparticles in this work. As simple one-dimension models, solid and hollow nanowire electrode particles are investigated. The results show that surface tensile stress produces compressive stresses through the electrode materials, especially reducing maximum tensile stress, which may become a resistance to brittle fracture. Owing to high special surface area, it is demonstrated that diffusion-induced stresses for hollow materials are largely reduced compared to solid electrode materials. The influences of surface modulus on diffusion-induced stresses are much stronger under generalized plane strain condition in comparison with plane strain condition. Analysis based on the Tresca criterion indicates that shear failure may occur at the inner surface with decreasing radius.
Morphological, structural, and emission characterization of trench defects in InGaN/GaN quantum well structures
Authors: Massabuau F. C.-P. , Sahonta S.-L. , Trinh-Xuan L. , Rhode S. , Puchtler T. J. , Kappers M. J. , Humphreys C. J. , Oliver R. A.
Published: November 2012

In a wide variety of InGaN/GaN quantum well (QW) structures, defects are observed which consist of a trench partially or fully enclosing a region of the QW having altered emission properties. For various different defect morphologies, cathodoluminescence studies suggest that the emission is redshifted in the enclosed region. Based on transmission electron microscopy and atomic force microscopy data, we suggest that the sub-surface structure of the trench defect consists of a basal plane stacking fault bounded by a stacking mismatch boundary, which terminates at the apex of a V-shaped trench.
Direct extraction of carrier mobility in graphene field-effect transistor using current-voltage and capacitance-voltage measurements
Authors: Zhang Zhiyong , Xu Huilong , Zhong Hua , Peng Lian-Mao
Published: November 2012

Top gated graphene field-effect transistors were fabricated using yttrium oxide film as high-κ gate dielectric, and the gate voltage dependent drain current and gate capacitance characteristics were both measured on one graphene device. Based on the two kinds of data sets, we developed a method to extract the carrier mobility of graphene field-effect transistors, along with some other parameters, such as series resistance and residual carrier density. Prior to previous method, this method could well fit the transfer curve of graphene field-effect transistor with high gate oxide capacitance since its carrier concentration is directly obtained from the experimental data rather than from analytic equation.
Benchmark Values: Thermochemistry of the Ionic Liquid [C4Py][Cl]
Authors: Verevkin Sergey P. , Zaitsau Dzmitry H. , Emel'yanenko Vladimir N. , Ralys Ricardas V. , Schick Christoph , Geppert-Rybczyńska Monika , Jayaraman Saivenkataraman , Maginn Edward J.
Published: November 2012

Differential scanning calorimetry (DSC) was used for the determination of the reaction enthalpy of the synthesis of the ionic liquid [C4Py][Cl] from pyridine and butyl chloride. A combination of DSC results with quantum chemical calculations presents an indirect technique to obtain enthalpy of vaporization of [C4Py][Cl]. In order to ascertain this indirect value, we used thermal gravimetric analysis (TGA) to derive enthalpy of vaporization directly from the isothermal mass-loss measurements. This new procedure was additionally validated with molecular dynamics (MD) simulations.
Effects of systemic administration or intrabursal injection of serotonin on puberty, first ovulation and follicular development in rats
Authors: Moran M. J. , Ayala M. E. , Gallegos E. , Romero J. , Chavira R. , Damián-Matsumura P. , Domínguez R.
Published: November 2012

To elucidate the role of serotonin in the onset of puberty, the effects of both systemic and in-ovarian bursa administration of serotonin on the neuroendocrine mechanism that modulates the onset of puberty, follicular development and first ovulation were evaluated. Two experiments were carried out. For the first, 25 or 37.5 mg kg–1 of bodyweight of serotonin creatinine sulfate was administered by a subcutaneous route to 30-day-old female rats. In the second experiment, serotonin creatinine sulfate was administered directly into the ovarian bursa of 34-day-old female rats. Systemic administration of 25 or 37.5 mg kg–1 of serotonin creatinine sulfate induced a delay in the ages of vaginal opening and first vaginal oestrus, a decrease in the number of ovulating animals, and serum concentrations of FSH, LH, oestradiol and progesterone. An increase in the number of Class 3 (>500 μm) and atretic follicles was observed in the ovaries of these animals. The administration of serotonin creatinine sulfate in the ovarian bursa did not modify the onset of puberty and ovulation, but a reduced serum concentration of oestradiol was observed. Our results suggest that serotonin acts on the components of the hypothalamus–hypophysis–ovary axis by modulating follicular development, ovarian functions and the onset of puberty.
Anatomical adaptations of the hind limb musculature of tree-kangaroos for arboreal locomotion (Marsupialia : Macropodinae)
Authors: Warburton Natalie M. , Yakovleff Maud , Malric Auréline
Published: November 2012

Tree-kangaroos (Dendrolagini) are Australasian marsupials that inhabit tropical forests of far north-eastern Queensland and New Guinea. The secondary adaptation of tree-kangaroos to an arboreal lifestyle from a terrestrial heritage offers an excellent opportunity to study the adaptation of the musculoskeletal system for arboreal locomotion, particularly from a template well adapted to terrestrial bipedal saltation. We present a detailed descriptive study of the hind limb musculature of Lumholtz’s tree-kangaroo (D. lumholtzi) in comparison to other macropodines to test whether the hind limb musculature of tree-kangaroos is functionally adapted to the different mechanical demands of locomotion in the uneven three-dimensional arboreal environment. The hind limb musculature of Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi), the western brush wallaby (Macropus irma), the western grey kangaroo (Macropus fuliginosus) and the quokka (Setonix brachyurus) are described. The hind limb anatomy of D. lumholtzi differed from that of the terrestrial macropodines in that the muscles had a greater degree of internal differentiation, relatively longer fleshy bellies and very short, stout tendons of insertion. There was also a modified arrangement of muscle origins and insertions that enhance mechanical advantage. Differences in the relative proportions of the hind limb muscle mass between tree-kangaroos and terrestrial macropodines reflect adaptation of the limb musculature of tree-kangaroos for arboreal locomotion. The hind limb musculature of Setonix was different to that of both Dendrolagus and Macropus, possibly reflecting its more basal phylogenetic position within the Macropodinae.
Directional grain growth from anisotropic kinetic roughening of grain boundaries in sheared colloidal crystals
Authors: Gokhale Shreyas , Nagamanasa K. Hima , Santhosh V. , Sood A. K. , Ganapathy Rajesh
Published: November 2012

The fabrication of functional materials via grain growth engineering implicitly relies on altering the mobilities of grain boundaries (GBs) by applying external fields. Although computer simulations have alluded to kinetic roughening as a potential mechanism for modifying GB mobilities, its implications for grain growth have remained largely unexplored owing to difficulties in bridging the widely separated length and time scales. Here, by imaging GB particle dynamics as well as grain network evolution under shear, we present direct evidence for kinetic roughening of GBs and unravel its connection to grain growth in driven colloidal polycrystals. The capillary fluctuation method allows us to quantitatively extract shear-dependent effective mobilities. Remarkably, our experiments reveal that for sufficiently large strains, GBs with normals parallel to shear undergo preferential kinetic roughening, resulting in anisotropic enhancement of effective mobilities and hence directional grain growth. Single-particle level analysis shows that the mobility anisotropy emerges from strain-induced directional enhancement of activated particle hops normal to the GB plane. We expect our results to influence materials fabrication strategies for atomic and block copolymeric polycrystals as well.
A switch between DNA polymerases δ and λ promotes error-free bypass of 8-oxo-G lesions
Authors: Markkanen Enni , Castrec Benoît , Villani Giuseppe , Hübscher Ulrich
Published: November 2012

7,8-Dihydro-8-oxoguanine (8-oxo-G) is a highly abundant and mutagenic lesion. Replicative DNA polymerases (pols) are slowed down at 8-oxo-G and insert both correct cytosine (C) and incorrect adenine (A) opposite 8-oxo-G, but they preferentially extend A:8-oxo-G mispairs. Nevertheless, 8-oxo-G bypass is fairly accurate in vivo. Thus, the question how correct bypass of 8-oxo-G lesions is accomplished despite the poor extension of C:8-oxo-G base pairs by replicative pols remains unanswered. Here we show that replicative pol δ pauses in front of 8-oxo-G and displays difficulties extending from correct C:8-oxo-G in contrast to extension from incorrect A:8-oxo-G. This leads to stalling of pol δ at 8-oxo-G after incorporation of correct C. This stalling at C:8-oxo-G can be overcome by a switch from pol δ to pols λ, β, or η, all of which are able to assist pol δ in 8-oxo-G bypass by translesion synthesis (TLS). Importantly, however, only pol λ selectively catalyzes the correct TLS past 8-oxo-G, whereas pols β and η show no selectivity and even preferentially enhance incorrect TLS. The selectivity of pol λ to promote the correct bypass depends on its N-terminal domain. Furthermore, pol λ
−/−
mouse embryonic fibroblast extracts display reduced 8-oxo-G TLS. Finally, the correct bypass of 8-oxo-G in gapped plasmids in mouse embryonic fibroblasts and HeLa cells is promoted in the presence of pol λ. Our findings suggest that even though 8-oxo-G is not a blocking lesion per se, correct replication over 8-oxo-G is promoted by a pol switch between pols δ and λ.
In vivo directed differentiation of pluripotent stem cells for skeletal regeneration
Authors: Levi Benjamin , Hyun Jeong S. , Montoro Daniel T. , Lo David D. , Chan Charles K. F. , Hu Shijun , Sun Ning , Lee Min , Grova Monica , Connolly Andrew J. , Wu Joseph C. , Gurtner Geoffrey C. , Weissman Irving L. , Wan Derrick C. , Longaker Michael T.
Published: November 2012

Pluripotent cells represent a powerful tool for tissue regeneration, but their clinical utility is limited by their propensity to form teratomas. Little is known about their interaction with the surrounding niche following implantation and how this may be applied to promote survival and functional engraftment. In this study, we evaluated the ability of an osteogenic microniche consisting of a hydroxyapatite-coated, bone morphogenetic protein-2–releasing poly-
l
-lactic acid scaffold placed within the context of a macroenvironmental skeletal defect to guide in vivo differentiation of both embryonic and induced pluripotent stem cells. In this setting, we found de novo bone formation and participation by implanted cells in skeletal regeneration without the formation of a teratoma. This finding suggests that local cues from both the implanted scaffold/cell micro- and surrounding macroniche may act in concert to promote cellular survival and the in vivo acquisition of a terminal cell fate, thereby allowing for functional engraftment of pluripotent cells into regenerating tissue.
Preconfiguration of the antigen-binding site during affinity maturation of a broadly neutralizing influenza virus antibody
Authors: Schmidt Aaron G. , Xu Huafeng , Khan Amir R. , O’Donnell Timothy , Khurana Surender , King Lisa R. , Manischewitz Jody , Golding Hana , Suphaphiphat Pirada , Carfi Andrea , Settembre Ethan C. , Dormitzer Philip R. , Kepler Thomas B. , Zhang Ruijun , Moody M. Anthony , Haynes Barton F. , Liao Hua-Xin , Shaw David E. , Harrison Stephen C.
Published: November 2012

Affinity maturation refines a naive B-cell response by selecting mutations in antibody variable domains that enhance antigen binding. We describe a B-cell lineage expressing broadly neutralizing influenza virus antibodies derived from a subject immunized with the 2007 trivalent vaccine. The lineage comprises three mature antibodies, the unmutated common ancestor, and a common intermediate. Their heavy-chain complementarity determining region inserts into the conserved receptor-binding pocket of influenza HA. We show by analysis of structures, binding kinetics and long time-scale molecular dynamics simulations that antibody evolution in this lineage has rigidified the initially flexible heavy-chain complementarity determining region by two nearly independent pathways and that this preconfiguration accounts for most of the affinity gain. The results advance our understanding of strategies for developing more broadly effective influenza vaccines.
V-stranding ellipsis and verbal identity
Authors: Lipták Anikó
Published: November 2012

This paper shows that the identity condition that characterizes V-stranding ellipsis is not verbal and does not only characterize syntactic heads. In some contexts, this type of ellipsis can strand phrasal material distinct from verbs that complies with the identity condition. The kind of contexts in which this can be attested are contexts in which ellipsis elides a TP licensed by a polarity focus head Σ0. This finding has important theoretical consequences for the explanation of the identity condition in V-stranding ellipsis, as it cannot be captured by current theories that put down identity to the special status of head movement in grammar.
Thinking in the right direction
Authors: Ott Dennis , de Vries Mark
Published: November 2012

We propose to analyze right-dislocation constructions in terms of clausal coordination, coupled with ellipsis. While neither rightward movement nor base-generation of backgrounded and afterthought phrases is descriptively accurate, we show that the facts follow straightforwardly on an analysis that takes the dislocated phrase to be the surface remnant of a second clause that is underlyingly parallel to the host clause and reduced by ellipsis at PF. Right-dislocated XPs are thus theoretically assimilated to sluiced wh-phrases, fragment answers, and other sentential fragments. We furthermore suggest that the two clauses in right-dislocation are syntactically related by an abstract coordinating head, making right-dislocation an instance of specifying coordination.
Against a minimal–augmented analysis of number
Authors: de Schepper Kees
Published: November 2012

Recently, it has been proposed that number on pronouns has minimal–augmented values instead of singular–plural values. This proposal leads to a split between nominal and pronominal number. I argue against this proposal as the pronominal paradigms of the world’s languages provide more evidence for a singular–plural analysis than for a minimal–augmented analysis.
Function and form in language theory and research
Authors: de Beaugrande Robert
Published: November 2012

It is argued that many of the major notions in 'mainstream' linguistic theory and method over the years have been influenced by a 'classical formalist' ambience that suited conventional ideas about how science ought to proceed but fostered an idealized 'frozen' conception of the language system in isolation from reality and society. Today, the tide is turning toward functionalist accounts of language; but the accompanying shift in our scientific programme calls for careful reflection. Some deep-lying motives for the shift are explored with a view to potential consequences.
A cross‐cultural study of adolescents' physical activity levels in France and Spain
Authors: Aibar Alberto , Bois Julien E. , Generelo Eduardo , Zaragoza Casterad Javier , Paillard Thierry
Published: November 2012

The goals of this study were (1) to describe and compare levels of physical activity (PA), assessed by accelerometry, of adolescents in two close Spanish and French cities according to gender and period of the week and (2) to assess, with reference to country and gender, the extent to which international PA guidelines were fulfilled. The PA of 401 adolescents (53.37% females) from France and Spain (55.72% French) aged 14.45±0.67 years was assessed with GT3X accelerometers for seven consecutive days to evaluate their habitual levels of moderate to vigorous physical activity (MVPA). Data collection took place from September to December 2010 in six public and state schools in France and Spain. There were significant differences in MVPA in terms of country, gender and period of the week. Spanish adolescents were more active than French adolescents, boys were more active than girls and MVPA was higher on weekdays than at weekends. French girls showed the lowest level of PA. Only 35.9% of the whole sample met the guidelines for PA in both countries. Governments of relevant countries, especially France, should adopt PA promotion policies targeted at adolescents in order to enhance their compliance with PA guidelines.