bluuebunny/crossref_metadata_2025 huggingface dataset:
Closed‐form solutions of coherent anti‐Stokes Raman signals generated by means of time asymmetric probe pulses
Authors: Marrocco M.
Published: June 2015

Under impulsive excitation of vibrational and rotational levels, coherent anti‐Stokes Raman scattering (CARS) is strongly dependent on the shape of the probe laser pulses. Here, we investigate this dependence for picosecond probe durations by showing for the first time that closed‐form solutions are achievable not only for fundamental probe pulses (Gaussian and hyperbolic secant) but also for their time asymmetric versions that better simulate some realistic experimental conditions. Thanks to this achievement, CARS lineshapes and time decays of Raman resonances can be studied without the numerical efforts that are common in the conventional approach to time‐resolved CARS. Copyright © 2015 John Wiley & Sons, Ltd.
Liver transplantation for critically Ill patients with secondary sclerosing cholangitis: Outcome and complications
Authors: Voigtländer Torsten , Jaeckel Elmar , Lehner Frank , Manns Michael P. , Lankisch Tim O.
Published: June 2015

Secondary sclerosing cholangitis in critically ill patients (SSC‐CIP) is a destructive cholangiopathy with a poor prognosis. Liver transplantation (LT) is an established therapeutic option in end‐stage liver disease but is insufficiently evaluated in patients with SSC‐CIP. Our aim was the retrospective analysis of the outcome and complications of patients with SSC‐CIP undergoing LT between 2002 and 2012. Demographic characteristics, laboratory, transplantation, and follow‐up data were compared to sex‐ and age‐matched patients undergoing LT because of other reasons. Quality of life (QoL) before and after LT was assessed in a retrospective telephone interview. LT was performed in 21 patients with SSC‐CIP. The main causes for intensive care unit admission comprised cardiothoracic surgery interventions (10/21, 48%), polytrauma (6/21, 29%), and pneumonia (3/21, 14%). Median follow‐up period after LT was 82 months (interquartile range [IQR], 37‐129) for patients with SSC‐CIP and 83 months (IQR, 55‐104) for control patients. Biopsy‐proven rejection episodes in patients with SSC‐CIP (4/21, 19%) were similar compared to control patients (12/60, 20%; P = 0.93). Cytomegalovirus infections were equal in both groups (10/21, 48% versus 25/60, 42%; P = 0.64). The 1‐, 3‐, and 5‐year survival rates of patients with SSC‐CIP versus control patients were 100% versus 98%, 86% versus 92%, and 76% versus 87%, respectively (P > 0.05). The QoL improved significantly after LT in SSC‐CIP. In conclusion, LT is a valid option for patients with SSC‐CIP with excellent long‐term outcome and improvement of QoL. Liver Transpl 21:1295‐1299, 2015. © 2015 AASLD.
Stability of two‐dimensional magnetohydrodynamic motions in the periodic case
Authors: Nowakowski Bernard , Zajączkowski Wojciech M.
Published: June 2015

We investigate the stability of two‐dimensional periodic solutions to magnetohydrodynamics equations in the class of three‐dimensional periodic solutions. We show the existence of global, strong three‐dimensional solutions to magnetohydrodynamics equations, which are close to two‐dimensional solutions. The advantage of our approach is that neither these solutions nor the external forces have to vanish at infinity. Copyright © 2015 John Wiley & Sons, Ltd.
Cell wall proteomics contributes to explore the functional proteins of Brachypodium distachyon grains
Authors: Fang Xianping , Chen Wenyue , Ma Huasheng
Published: June 2015

The plant cell wall is the first barrier in response to external stimuli and cell wall proteins (CWPs) can play an important role in the modulation of plant growth and development. In the past 10 years, the plant cell wall proteomics has increasingly become a very active research filed, which provides a broader understanding of CWPs for people. The cell wall proteome of Arabidopsis, rice, and other model plants has begun to take shape, and proteomic technology has become an effective way to identify the candidate functional CWPs in large scale. The challenging work of Francin‐Allami et al. (Proteomics 2015, 15, 2296–2306) is a vital step toward building the most extensive cell wall proteome of a monocot species. They identified 299 cell wall proteins in Brachypodium distachyon grains, and also compared the grain cell wall proteome with those of B. distachyon culms and leaves, which provides a new perspective for further explaining the plant cell wall structures and remodeling mechanism.
Relationships between syn-orogenic sedimentation and nappe emplacement in the hinterland of the Variscan belt in NW Iberia deduced from detrital zircons
Authors: MARTÍNEZ CATALÁN JOSÉ R. , GONZÁLEZ CLAVIJO EMILIO , MEIRELES CARLOS , DÍEZ FERNÁNDEZ RUBÉN , BEVIS JAMES
Published: June 2015

Flysch-type, syn-orogenic deposits of Carboniferous age occur in relation to the emplacement of a large allochthonous nappe stack in the Variscan belt of NW Iberia. New U–Pb age populations of detrital zircons obtained using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are considered together with others from previously dated samples to establish the relationships between sedimentation and thrusting. The age populations of four syn-orogenic formations are compared with those of the pre-orogenic sequence in the Autochthon and Parautochthon, representing the Gondwanan passive margin, and in the Allochthon, formed by peri-Gondwanan and oceanic terranes. In addition, a new structural study has been carried out to understand the relationships between the syn-orogenic deposits and the development of Variscan structures. The aims are to identify the sources of sediments and to establish the relationship between Variscan structural evolution and syn-orogenic sedimentation. Development of a forebulge outwards from the allochthonous front, deduced from the structural study, suggests the existence of depocentres that hosted the syn-orogenic sediments. Together with the trend shown by the more recent zircons in each formation, that are younger towards the external zones, the data suggest that sedimentation occurred in progressively migrating depocentres formed in front of the allochthonous wedge during its emplacement. The zircon age populations point to the Allochthon as the main source of detritus for the syn-orogenic basins, with perhaps a limited participation of the Parautochthon and Autochthon in the younger formations.
An Organizational Field Approach to Corporate Rationality: The Role of Stakeholder Activism
Authors: O’Connell Lenahan L. , Stephens Carroll U. , Betz Michael , Shepard Jon M. , Hendry Jamie R.
Published: June 2015

This paper contends that rationality is more properly evaluated as a property of an organization’s relationships with its stakeholders than of the organization itself. We predicate our approach on the observation that stakeholders can hold goals quite distinct from those of owners and top managers, and these too can be rationally pursued. We build upon stakeholder theory and Weber’s classic distinction betweenwertrationalitatandzweckrationalitat, adding to them the “new institutionalist” concept of the organization field (1983, 1991). Stakeholders employ a variety of direct and indirect mechanisms to rationalize relations with the firm. We discuss four: internal subunits, legislated stakeholder participation, legislated access to information, and direct stakeholder activism. These developments are blurring the distinction between the environment and the organization by importing the values and goals of external stakeholders into the internal organization. They are also precipitating a more structured set of relationships among the actors who comprise the field. To the extent that thezweckrationalitatvalues of managers and owners as well as thewertrationalitatconcerns of stakeholders are met, the firm is more rational.
Dysfunction of Mouse Cerebral Arteries during Early Aging
Authors: Balbi Matilde , Ghosh Mitrajit , Longden Thomas A , Vega Max Jativa , Gesierich Benno , Hellal Farida , Lourbopoulos Athanasios , Nelson Mark T , Plesnila Nikolaus
Published: June 2015

Aging leads to a gradual decline in the fidelity of cerebral blood flow (CBF) responses to neuronal activation, resulting in an increased risk for stroke and dementia. However, it is currently unknown when age-related cerebrovascular dysfunction starts or which vascular components and functions are first affected. The aim of this study was to examine the function of microcirculation throughout aging in mice. Microcirculation was challenged by inhalation of 5% and 10% CO2 or by forepaw stimulation in 6-week, 8-month, and 12-month-old FVB/N mice. The resulting dilation of pial vessels and increase in CBF was measured by intravital fluorescence microscopy and laser Doppler fluxmetry, respectively. Neurovascular coupling and astrocytic endfoot Ca2+ were measured in acute brain slices from 18-month-old mice. We did not reveal any changes in CBF after CO2 reactivity up to an age of 12 months. However, direct visualization of pial vessels by in vivo microscopy showed a significant, age-dependent loss of CO2 reactivity starting at 8 months of age. At the same age neurovascular coupling was also significantly affected. These results suggest that aging does not affect cerebral vessel function simultaneously, but starts in pial microvessels months before global changes in CBF are detectable.
Quantification of [11C]PIB PET for Imaging Myelin in the Human Brain: A Test—Retest Reproducibility Study in High-Resolution Research Tomography
Authors: Veronese Mattia , Bodini Benedetta , García-Lorenzo Daniel , Battaglini Marco , Bongarzone Salvatore , Comtat Claude , Bottlaender Michel , Stankoff Bruno , Turkheimer Federico E
Published: June 2015

An accurate in vivo measure of myelin content is essential to deepen our insight into the mechanisms underlying demyelinating and dysmyelinating neurological disorders, and to evaluate the effects of emerging remyelinating treatments. Recently [11C]PIB, a positron emission tomography (PET) tracer originally conceived as a beta-amyloid marker, has been shown to be sensitive to myelin changes in preclinical models and humans. In this work, we propose a reference-region methodology for the voxelwise quantification of brain white-matter (WM) binding for [11C]PIB. This methodology consists of a supervised procedure for the automatic extraction of a reference region and the application of the Logan graphical method to generate distribution volume ratio (DVR) maps. This approach was assessed on a test–retest group of 10 healthy volunteers using a high-resolution PET tomograph. The [11C]PIB PET tracer binding was shown to be up to 23% higher in WM compared with gray matter, depending on the image reconstruction. The DVR estimates were characterized by high reliability (outliers < 1%) and reproducibility (intraclass correlation coefficient (ICC) > 0.95). [11C]PIB parametric maps were also found to be significantly correlated ( R2 > 0.50) to mRNA expressions of the most represented proteins in the myelin sheath. On the contrary, no correlation was found between [11C]PIB imaging and nonmyelin-associated proteins.
Entanglement dynamics in the presence of controlled unital noise
Authors: Shaham A. , Halevy A. , Dovrat L. , Megidish E. , Eisenberg H. S.
Published: June 2015

Quantum entanglement is notorious for being a very fragile resource. Significant efforts have been put into the study of entanglement degradation in the presence of a realistic noisy environment. Here, we present a theoretical and an experimental study of the decoherence properties of entangled pairs of qubits. The entanglement dynamics of maximally entangled qubit pairs is shown to be related in a simple way to the noise representation in the Bloch sphere picture. We derive the entanglement level in the case when both qubits of a Bell state are transmitted through any arbitrary unital Pauli channel and compare it to the case when the channel is applied only to one of the qubits. The dynamics of both cases was verified experimentally using an all-optical setup. We further investigated the evolution of partially entangled initial states. Different dynamics was observed for initial mixed and pure states of the same entanglement level.
Change of Electronic Structures by Dopant-Induced Local Strain
Authors: Hyeong Kim Gyu , Jeong Sukmin
Published: June 2015

Ag-induced Si(111)-"Equation missing" surfaces ("Equation missing"-Ag) exhibit unusual electronic structures that cannot be explained by the conventional rigid band model and charge transfer model. The ("Equation missing"-Ag surfaces feature a free-electron-like parabolic band, the S1 band, that selectively shifts downward upon the adsorption of noble metal or alkali metal adatoms. Furthermore, the downward shift of S1 is independent of the type of dopants, Au, Ag and Na. According to charge transfer analysis, Au adatoms accumulate electrons from the substrate and become negatively charged, whereas Na adatoms become positively charged, which indicates that S1 should shift in the opposite direction for both the adatoms. Investigation of calculated structures, calculation of model structures and tight-binding analysis disclose that the changes in the electronic structure are closely related to the average Ag-Ag distance in the substrate and have their origin in the local strain induced by dopants (adatoms). This explanation implies that the electronic structure is irrespective of the dopant characters itself and paves a new way for understanding the electronic structures associated with the presence of dopants.
CAN Canopy Addition of Nitrogen Better Illustrate the Effect of Atmospheric Nitrogen Deposition on Forest Ecosystem?
Authors: Zhang Wei , Shen Weijun , Zhu Shidan , Wan Shiqiang , Luo Yiqi , Yan Junhua , Wang Keya , Liu Lei , Dai Huitang , Li Peixue , Dai Keyuan , Zhang Weixin , Liu Zhanfeng , Wang Faming , Kuang Yuanwen , Li Zhian , Lin Yongbiao , Rao Xingquan , Li Jiong , Zou Bi , Cai Xian , Mo Jiangming , Zhao Ping , Ye Qing , Huang Jianguo , Fu Shenglei
Published: June 2015

Increasing atmospheric nitrogen (N) deposition could profoundly impact community structure and ecosystem functions in forests. However, conventional experiments with understory addition of N (UAN) largely neglect canopy-associated biota and processes and therefore may not realistically simulate atmospheric N deposition to generate reliable impacts on forest ecosystems. Here we, for the first time, designed a novel experiment with canopy addition of N (CAN) vs. UAN and reviewed the merits and pitfalls of the two approaches. The following hypotheses will be tested: i) UAN overestimates the N addition effects on understory and soil processes but underestimates those on canopy-associated biota and processes, ii) with low-level N addition, CAN favors canopy tree species and canopy-dwelling biota and promotes the detritus food web and iii) with high-level N addition, CAN suppresses canopy tree species and other biota and favors rhizosphere food web. As a long-term comprehensive program, this experiment will provide opportunities for multidisciplinary collaborations, including biogeochemistry, microbiology, zoology and plant science to examine forest ecosystem responses to atmospheric N deposition.
Single-chip photonic transceiver based on bulk-silicon, as a chip-level photonic I/O platform for optical interconnects
Authors: Kim Gyungock , Park Hyundai , Joo Jiho , Jang Ki-Seok , Kwack Myung-Joon , Kim Sanghoon , Gyoo Kim In , Hyuk Oh Jin , Ae Kim Sun , Park Jaegyu , Kim Sanggi
Published: June 2015

When silicon photonic integrated circuits (PICs), defined for transmitting and receiving optical data, are successfully monolithic-integrated into major silicon electronic chips as chip-level optical I/Os (inputs/outputs), it will bring innovative changes in data computing and communications. Here, we propose new photonic integration scheme, a single-chip optical transceiver based on a monolithic-integrated vertical photonic I/O device set including light source on bulk-silicon. This scheme can solve the major issues which impede practical implementation of silicon-based chip-level optical interconnects. We demonstrated a prototype of a single-chip photonic transceiver with monolithic-integrated vertical-illumination type Ge-on-Si photodetectors and VCSELs-on-Si on the same bulk-silicon substrate operating up to 50 Gb/s and 20 Gb/s, respectively. The prototype realized 20 Gb/s low-power chip-level optical interconnects for λ ~ 850 nm between fabricated chips. This approach can have a significant impact on practical electronic-photonic integration in high performance computers (HPC), cpu-memory interface, hybrid memory cube and LAN, SAN, data center and network applications.
Chip-based array magnetic solid phase microextraction on-line coupled with inductively coupled plasma mass spectrometry for the determination of trace heavy metals in cells
Authors: Wang Han , Wu Zhekuan , Chen Beibei , He Man , Hu Bin
Published: June 2015

An on-line chip-based array magnetic solid phase microextraction – ICP-MS system was established for the determination of trace elements in cells which is critical to metallomics research.
Identification and quantitative determination of carbohydrate molecules in Greek honey by employing 13C NMR spectroscopy
Authors: Kazalaki Aristea , Misiak Maria , Spyros Apostolos , Dais Photis
Published: June 2015

A methodology based on 13C NMR spectroscopy was employed to detect and quantify fourteen mono-, di- and trisaccharide molecules in authentic Greek honey samples with no prior separation.
Azo-functionalized microporous organic polymers: synthesis and applications in CO2 capture and conversion
Authors: Yang Zhenzhen , Zhang Hongye , Yu Bo , Zhao Yanfei , Ma Zhishuang , Ji Guipeng , Han Buxing , Liu Zhimin
Published: June 2015

Azo-functionalized microporous organic polymers were synthesized under mild conditions (25 °C, 1 h, yield: >95%), and displayed high CO2 capacity and high performances for catalyzing the methylation of amines with CO2 under low pressure (0.5 MPa).
Comment on “Charge transfer to solvent dynamics in iodide aqueous solution studied at ionization threshold” by A. Kothe, M. Wilke, A. Moguilevski, N. Engel, B. Winter, I. Y. Kiyan and E. F. Aziz, Phys. Chem. Chem. Phys., 2015, 17, 1918
Authors: Ritze Hans-Hermann , Lübcke Andrea
Published: June 2015

We critically discuss recent results about CTTS dynamics in aqueous iodide solution.
Novel helical assembly of a Pt(ii) phenylbipyridine complex directed by metal–metal interaction and aggregation-induced circularly polarized emission
Authors: Ikeda Toshiaki , Takayama Midori , Kumar Jatish , Kawai Tsuyoshi , Haino Takeharu
Published: June 2015

Pt(ii) complexes possessing phenylisoxazole moieties self-assembled to form helical stacked aggregates which display aggregation-induced circularly polarized luminescence.
Antioxidant and antiproliferative activities of polysaccharide fractions from litchi pulp
Authors: Huang Fei , Zhang Ruifen , Dong Lihong , Guo Jinxin , Deng Yuanyuan , Yi Yang , Zhang Mingwei
Published: June 2015

Three litchi polysaccharide fractions (LPFs), LP-4, LP-6 and LP-8, were obtained by fractional precipitation using 40%, 60% and 80% ethanol, respectively.
Synthesis and biological evaluation of 4′-[(benzimidazol-1-yl) methyl]biphenyl-2-amides as dual angiotensin II and endothelin A receptor antagonists
Authors: Han Xiao-Feng , Xue Wei-Zhe , Hao Li-Ping , Zhou Zhi-Ming
Published: June 2015

Discovery of new benzimidazoles as potent dual AT1 and ETA receptor antagonists with the novel N-(1H-tetrazol-5-yl)-amide fragment.
Development of one-step synthesized LDH reinforced multifunctional poly(amide–imide) matrix containing xanthene rings: study on thermal stability and flame retardancy
Authors: Hajibeygi M. , Shabanian M. , Moghanian H. , Khonakdar H. A. , Häußler L.
Published: June 2015

New exfoliated poly(amide–imide)/Zn–Al layered double hydroxide (LDH) nanocomposites were synthesized by solution intercalation using synthesized organo-modified LDH (OLDH) as nanofiller obtained by one-step method.
Green surfactant of marine origin exerting a cytotoxic effect on cancer cell lines
Authors: Das Palashpriya , Sarkar Siddik , Mandal Mahitosh , Sen Ramkrishna
Published: June 2015

The present work reveals the efficacy of a marine antimicrobial lipopeptide biosurfactant in blocking proliferation of breast cancer and colon cancer cell lines, without displaying any significant antioxidant activity.
Enhanced reproducibility of the high efficiency perovskite solar cells via a thermal treatment
Authors: Kim Yun-Jeong , Tung Duong-Thanh , Choi Hyung-Jin , Park Byeong-Ju , Eom Ji-Ho , Kim Kyung-Soo , Jeong Jong-Ryul , Yoon Soon-Gil
Published: June 2015

Thermal treatment of the cell samples after dc sputtering of the Au electrodes enhanced the reproducibility of the perovskite cell efficiencies because the thermal annealing induced the strong adhesion between each layer of the cells.
Selective palladium-catalysed arylation of 2,6-dibromopyridine using N-heterocyclic carbene ligands
Authors: Prajapati D. , Schulzke C. , Kindermann M. K. , Kapdi A. R.
Published: June 2015

A selective palladium-catalysed arylation of 2,6-dibromopyridine has been developed by employingN-heterocyclic carbene ligands. Selective mono-arylation was performed in water/acetonitrile solvent at ambient temperature and low catalyst loading.
Influence of phase transformation pathways on electrochemical properties by using thermally derived solid-solution LiFePO4nanoparticles
Authors: Yoo Sunyoung , Kang Byoungwoo
Published: June 2015

A sample with the solid-solution phase was prepared by heating a sample that contained two phases, LiFePO4and FePO4. The two samples had similar thermodynamic properties, but different kinetic properties. The different phase transformation pathways strongly affected the electrochemical kinetic properties of LiFePO4NPs.
Thermo-processable covalent scaffolds with reticular hierarchical porosity and their high efficiency capture of carbon dioxide
Authors: Moon Su-Young , Jeon Eunkyung , Bae Jae-Sung , Park Mi-Kyoung , Kim Chan , Noh Do Young , Lee Eunji , Park Ji-Woong
Published: June 2015

Hierarchically porous organic network-based scaffolds comprised of reticulated micro-, meso-, and macropores were demonstrated for high efficiency capture of carbon dioxide.
Near ultraviolet photochemistry of 2-bromo- and 2-iodothiophene: Revealing photoinduced ring opening in the gas phase?
Authors: Marchetti Barbara , Karsili Tolga N. V. , Kelly Orla , Kapetanopoulos Panos , Ashfold Michael N. R.
Published: June 2015

Velocity map imaging methods, with a new and improved ion optics design, have been used to explore the near ultraviolet photodissociation dynamics of gas phase 2-bromo- and 2-iodothiophene molecules. In both cases, the ground (X) and spin-orbit excited (X*) (where X = Br, I) atom products formed at the longest excitation wavelengths are found to recoil with fast, anisotropic velocity distributions, consistent with prompt C–X bond fission following excitation via a transition whose dipole moment is aligned parallel to the breaking bond. Upon tuning to shorter wavelengths, this fast component fades and is progressively replaced by a slower, isotropic recoil distribution. Complementary electronic structure calculations provide a plausible explanation for this switch in fragmentation behaviour—namely, the opening of a rival C–S bond extension pathway to a region of conical intersection with the ground state potential energy surface. The resulting ground state molecules are formed with more than sufficient internal energy to sample the configuration space associated with several parent isomers and to dissociate to yield X atom products in tandem with both cyclic and ring-opened partner fragments.
Quantifying charge resonance and multiexciton character in coupled chromophores by charge and spin cumulant analysis
Authors: Luzanov Anatoliy V. , Casanova David , Feng Xintian , Krylov Anna I.
Published: June 2015

We extend excited-state structural analysis to quantify the charge-resonance and multi-exciton character in wave functions of weakly interacting chromophores such as molecular dimers. The approach employs charge and spin cumulants which describe inter-fragment electronic correlations in molecular complexes. We introduce indexes corresponding to the weights of local, charge resonance, and biexciton (with different spin structure) configurations that can be computed for general wave functions thus allowing one to quantify the character of doubly excited states. The utility of the approach is illustrated by applications to several small dimers, e.g., He-H2, (H2)2, and (C2H4)2, using full and restricted configuration interaction schemes. In addition, we present calculations for several systems relevant to singlet fission, such as tetracene, 1,6-diphenyl-1,3,5-hexatriene, and 1,3-diphenylisobenzofuran dimers.
Theory of molecule metal nano-particle interaction: Quantum description of plasmonic lasing
Authors: Zhang Yuan , May Volkhard
Published: June 2015

The recent quantum description of a few molecules interacting with plasmon excitations of a spherical metal nano-particle (MNP) as presented in the work of Zhang and May [Phys. Rev. B 89, 245441 (2014)] is extended to systems with up to 100 molecules. We demonstrate the possibility of multiple plasmon excitation and describe their conversion into far-field photons. The calculation of the steady-state photon emission spectrum results in an emission line-narrowing with an increasing number of molecules coupled to the MNP. This is considered as an essential criterion for the action of the molecule-MNP system as a nano-laser. To have exact results for systems with up to 20 molecules, we proceed as recently described by Richter et al. [Phys. Rev. B 91, 035306 (2015)] and study a highly symmetric system. It assumes an equatorial and regular position of identical molecules in such a way that their coupling is dominated by that to a single MNP dipole-plasmon excitation. Changing from the exact computation of the system’s complete density matrix to an approximate theory based on the reduced plasmon density matrix, systems with more than 100 molecules can be described. Finally, nonlinear rate equations are proposed which reproduce the mean number of excited plasmons in their dependence of the number of molecules and of the used pump rate. The second order intensity correlation function of emitted photons is related to the respective plasmon correlation function which approaches unity when the system starts lasing.
A linear radio frequency plasma reactor for potential and current mapping in a magnetized plasma
Authors: Faudot E. , Devaux S. , Moritz J. , Heuraux S. , Molina Cabrera P. , Brochard F.
Published: June 2015

Langmuir probe measurements in front of high power ion cyclotron resonant frequency antennas are not possible or simply too noisy to be analyzed properly. A linear experiment is a radio frequency (RF) magnetized plasma discharge reactor designed to probe the rectified potential in front of such antennas but at low power level (1 kW) to next improve antenna design and mitigate sheath effects. The maximum magnetic field is 0.1 T, and the RF amplifier can work between 10 kHz and 250 MHz allowing ion cyclotron resonances for argon or helium. The first measurements with no magnetic field are presented here, especially 2D potential maps extracted from the RF compensated probe measurements yield ni ≈ 1015 m−3 and Te ≈ 2 eV for RF power lower than 100 W. Series resonances in the chamber are highlighted and allow to deduce the plasma parameters from a simple equivalent impedance model of the plasma in helium gas. Next studies will be focused on magnetized plasmas and especially magnetized RF sheaths.
An atomic orbital-based formulation of the complete active space self-consistent field method on graphical processing units
Authors: Hohenstein Edward G. , Luehr Nathan , Ufimtsev Ivan S. , Martínez Todd J.
Published: June 2015

Despite its importance, state-of-the-art algorithms for performing complete active space self-consistent field (CASSCF) computations have lagged far behind those for single reference methods. We develop an algorithm for the CASSCF orbital optimization that uses sparsity in the atomic orbital (AO) basis set to increase the applicability of CASSCF. Our implementation of this algorithm uses graphical processing units (GPUs) and has allowed us to perform CASSCF computations on molecular systems containing more than one thousand atoms. Additionally, we have implemented analytic gradients of the CASSCF energy; the gradients also benefit from GPU acceleration as well as sparsity in the AO basis.
Strong transmittance above the light line in mid-infrared two-dimensional photonic crystals
Authors: Kraeh Christian , Martinez-Hurtado J. L. , Zeitlmair Martin , Popescu Alexandru , Hedler Harry , Finley Jonathan J.
Published: June 2015

The mid-infrared region of the electromagnetic spectrum between 3 and 8 μm hosts absorption lines of gases relevant for chemical and biological sensing. 2D photonic crystal structures capable of guiding light in this region of the spectrum have been widely studied, and their implementation into miniaturized sensors has been proposed. However, light guiding in conventional 2D photonic crystals is usually restricted to a frequency range below the light line, which is the dispersion relation of light in the media surrounding the structures. These structures rely on total internal reflection for confinement of the light in z-direction normal to the lattice plane. In this work, 2D mid-infrared photonic crystals consisting of microtube arrays that mitigate these limitations have been developed. Due to their high aspect ratios of ∼1:30, they are perceived as semi-infinite in the z-direction. Light transmission experiments in the 5–8 μm range reveal attenuations as low as 0.27 dB/100 μm, surpassing the limitations for light guiding above the light line in conventional 2D photonic crystals. Fair agreement is obtained between these experiments, 2D band structure and transmission simulations.
Finite-time barriers to front propagation in two-dimensional fluid flows
Authors: Mahoney John R. , Mitchell Kevin A.
Published: June 2015

Recent theoretical and experimental investigations have demonstrated the role of certain invariant manifolds, termed burning invariant manifolds (BIMs), as one-way dynamical barriers to reaction fronts propagating within a flowing fluid. These barriers form one-dimensional curves in a two-dimensional fluid flow. In prior studies, the fluid velocity field was required to be either time-independent or time-periodic. In the present study, we develop an approach to identify prominent one-way barriers based only on fluid velocity data over a finite time interval, which may have arbitrary time-dependence. We call such a barrier a burning Lagrangian coherent structure (bLCS) in analogy to Lagrangian coherent structures (LCSs) commonly used in passive advection. Our approach is based on the variational formulation of LCSs using curves of stationary “Lagrangian shear,” introduced by Farazmand et al. [Physica D 278–279, 44 (2014)] in the context of passive advection. We numerically validate our technique by demonstrating that the bLCS closely tracks the BIM for a time-independent, double-vortex channel flow with an opposing “wind.”
The diene isomerization energies dataset: A difficult test for double-hybrid density functionals?
Authors: Wykes M. , Pérez-Jiménez A. J. , Adamo C. , Sancho-García J. C.
Published: June 2015

We have systematically analyzed the performance of some representative double-hybrid density functionals (including PBE0-DH, PBE-QIDH, PBE0-2, XYG3, XYGJ-OS, and xDH-PBE0) for a recently introduced database of diene isomerization energies. Double-hybrid models outperform their corresponding hybrid forms (for example, PBE0-DH, PBE0-2, and PBE-QIDH are more accurate than PBE0) and the XYG3, XYGJ-OS, and xDH-PBE0 functionals perform excellently, providing root mean square deviation values within “calibration accuracy.” XYGJ-OS and xDH-PBE0 also rival the best performing post-Hartree-Fock methods at a substantially lower cost.
Bow-shock instability induced by Helmholtz resonator-like feedback in slipstream
Authors: Ohnishi Naofumi , Sato Yosuke , Kikuchi Yuta , Ohtani Kiyonobu , Yasue Kanako
Published: June 2015

Bow-shock instability has been experimentally observed in a low-γ flow. To clarify its mechanism, a parametric study was conducted with three-dimensional numerical simulations for specific heat ratio γ and Mach number M. A critical boundary of the instability was found in the γ-M parametric space. The bow shock tends to be unstable with low γ and high M, and the experimental demonstration was designed based on this result. The experiments were conducted with the ballistic range of the single-stage powder gun mode using HFC-134a of γ = 1.12 at Mach 9.6. Because the deformation of the shock front was observed in a shadowgraph image, the numerical prediction was validated to some extent. The theoretical estimation of vortex formation in a curved shock wave indicates that the generated vorticity is proportional to the density ratio across the shock front and that the critical density ratio can be predicted as ∼10. A strong slipstream from the surface edge generates noticeable acoustic waves because it can be deviated by the upstream flow. The acoustic waves emitted by synchronizing the vortex formation can propagate upstream and may trigger bow-shock instability. This effect should be emphasized in terms of unstable shock formation around an edged flat body.
Theoretical calculations of rotationally inelastic collisions of He with NaK(A 1Σ+): Transfer of population, orientation, and alignment
Authors: Malenda R. F. , Price T. J. , Stevens J. , Uppalapati S. L. , Fragale A. , Weiser P. M. , Kuczala A. , Talbi D. , Hickman A. P.
Published: June 2015

We have performed extensive calculations to investigate thermal energy, rotationally inelastic collisions of NaK (A1Σ+) with He. We determined a potential energy surface using a multi-reference configuration interaction wave function as implemented by the GAMESS electronic structure code, and we have performed coupled channel scattering calculations using the Arthurs and Dalgarno formalism. We also calculate the Grawert coefficients Bλ(j, j′) for each j → j′ transition. These coefficients are used to determine the probability that orientation and alignment are preserved in collisions taking place in a cell environment. The calculations include all rotational levels with j or j′ between 0 and 50, and total (translational and rotational) energies in the range 0.0002–0.0025 a.u. (∼44–550 cm−1). The calculated cross sections for transitions with even values of Δj tend to be larger than those for transitions with odd Δj, in agreement with the recent experiments of Wolfe et al. (J. Chem. Phys. 134, 174301 (2011)). The calculations of the energy dependence of the cross sections and the calculations of the fraction of orientation and alignment preserved in collisions also exhibit distinctly different behaviors for odd and even values of Δj. The calculations also indicate that the average fraction of orientation or alignment preserved in a transition becomes larger as j increases. We interpret this behavior using the semiclassical model of Derouard, which also leads to a simple way of visualizing the distribution of the angles between the initial and final angular momentum vectors j and j′. Finally, we compare the exact quantum results for j → j′ transitions with results based on the simpler, energy sudden approximation. That approximation is shown to be quite accurate.
Inner-shell photoionization and core-hole decay of Xe and XeF2
Authors: Southworth Stephen H. , Wehlitz Ralf , Picón Antonio , Lehmann C. Stefan , Cheng Lan , Stanton John F.
Published: June 2015

Photoionization cross sections and partial ion yields of Xe and XeF2 from Xe 3d5/2, Xe 3d3/2, and F 1s subshells in the 660–740 eV range are compared to explore effects of the F ligands. The Xe 3d-ϵf continuum shape resonances dominate the photoionization cross sections of both the atom and molecule, but prominent resonances appear in the XeF2 cross section due to nominal excitation of Xe 3d and F 1s electrons to the lowest unoccupied molecular orbital (LUMO), a delocalized anti-bonding MO. Comparisons of the ion products from the atom and molecule following Xe 3d photoionization show that the charge-state distribution of Xe ions is shifted to lower charge states in the molecule along with production of energetic F+ and F2+ ions. This suggests that, in decay of a Xe 3d core hole, charge is redistributed to the F ligands and the system dissociates due to Coulomb repulsion. The ion products from excitation of the F 1s-LUMO resonance are different and show strong increases in the yields of Xe+ and F+ ions. The subshell ionization thresholds, the LUMO resonance energies, and their oscillator strengths are calculated by relativistic coupled-cluster methods and agree well with measurements.
AlN texturing and piezoelectricity on flexible substrates for sensor applications
Authors: Smecca Emanuele , Maita Francesco , Pellegrino Giovanna , Vinciguerra Vincenzo , La Magna Luigi , Mirabella Salvo , Maiolo Luca , Fortunato Guglielmo , Condorelli Guglielmo G. , Alberti Alessandra
Published: June 2015

We show that AlN-based piezocapacitors with relatively high piezoelectric coefficient (d33) values (3–4 pC/N) can be fabricated on polyimide (PI) substrates at 160 °C or even at room temperature by sputtering processes. With respect to PI, a reduction of the piezoelectric performances was observed on polyethylene naphthalate (PEN). With the same approach, a d33 value as high as 8 pC/N was achieved on rigid substrates (SiO2/Si). In all cases, a thin Al buffer layer was deposited, immediately before AlN, without breaking the vacuum in the deposition chamber, in order to preserve the interface from contaminations that would obstruct the optimal atomic stratification with the desired [0001] growth axis. The piezoelectric behavior was thus correlated to the degree of texturing of the AlN layer through the evaluation of the XRD texturing coefficients and to the morphology by means of AFM analyses. We show that a high level of roughness introduced by the PEN substrate, coupled with the effect of the substrate flexibility on the piezoelectric coefficient, reduces the impact of the AlN texturing on the d33 values.
Transverse thermoelectric effect in La0.67Sr0.33MnO3|SrRuO3 superlattices
Authors: Shiomi Y. , Handa Y. , Kikkawa T. , Saitoh E.
Published: June 2015

Transverse thermoelectric effects in response to an out-of-plane heat current have been studied in an external magnetic field for ferromagnetic superlattices consisting of La0.67Sr0.33MnO3 and SrRuO3 layers. The superlattices were fabricated on SrTiO3 substrates by pulsed laser deposition. We found that the sign of the transverse thermoelectric voltage for the superlattices is opposite to that for La0.67Sr0.33MnO3 and SrRuO3 single layers at 200 K, implying an important role of spin Seebeck effects inside the superlattices. At 10 K, the magnetothermoelectric curves shift from the zero field due to an antiferromagnetic coupling between layers in the superlattices.
Homoclinic behaviors and chaotic motions of double layered viscoelastic nanoplates based on nonlocal theory and extended Melnikov method
Authors: Wang Yu , Li Feng-Ming , Wang Yi-Ze
Published: June 2015

The nonlinear dynamical equations are established for the double layered viscoelastic nanoplates (DLNP) subjected to in-plane excitation based on the nonlocal theory and von Kármán large deformation theory. The extended high dimensional homoclinic Melnikov method is employed to study the homoclinic phenomena and chaotic motions for the parametrically excited DLNP system. The criteria for the homoclinic transverse intersection for both the asynchronous and synchronous buckling cases are proposed. Lyapunov exponents and phase portraits are obtained to verify the Melnikov-type analysis. The influences of structural parameters on the transverse homoclinic orbits and homoclinic bifurcation sets are discussed for the two buckling cases. Some novel phenomena are observed in the investigation. It should be noticed that the nonlocal effect on the homoclinic behaviors and chaotic motions is quite remarkable. Hence, the small scale effect should be taken into account for homoclinic and chaotic analysis for nanostructures. It is significant that the nonlocal effect on the homoclinic phenomena for the asynchronous buckling case is quite different from that for the synchronous buckling case. Moreover, due to the van der Walls interaction between the layers, the nonlocal effect on the homoclinic behaviors and chaotic motions for high order mode is rather tiny under the asynchronous buckling condition.
Fluctuating hydrodynamics of multi-species reactive mixtures
Authors: Bhattacharjee Amit Kumar , Balakrishnan Kaushik , Garcia Alejandro L. , Bell John B. , Donev Aleksandar
Published: June 2015

We formulate and study computationally the fluctuating compressible Navier-Stokes equations for reactive multi-species fluid mixtures. We contrast two different expressions for the covariance of the stochastic chemical production rate in the Langevin formulation of stochastic chemistry, and compare both of them to predictions of the chemical master equation for homogeneous well-mixed systems close to and far from thermodynamic equilibrium. We develop a numerical scheme for inhomogeneous reactive flows, based on our previous methods for non-reactive mixtures [Balakrishnan , Phys. Rev. E 89, 013017 (2014)]. We study the suppression of non-equilibrium long-ranged correlations of concentration fluctuations by chemical reactions, as well as the enhancement of pattern formation by spontaneous fluctuations. Good agreement with available theory demonstrates that the formulation is robust and a useful tool in the study of fluctuations in reactive multi-species fluids. At the same time, several problems with Langevin formulations of stochastic chemistry are identified, suggesting that future work should examine combining Langevin and master equation descriptions of hydrodynamic and chemical fluctuations.
Large eddy simulation of a large wind-turbine array in a conventionally neutral atmospheric boundary layer
Authors: Allaerts Dries , Meyers Johan
Published: June 2015

Under conventionally neutral conditions, the boundary layer is frequently capped by an inversion layer, which counteracts vertical entrainment of kinetic energy. Very large wind farms are known to depend on vertical entrainment to transport energy from above the farm towards the turbines. In this study, large eddy simulations of an infinite wind-turbine array in a conventionally neutral atmospheric boundary layer are performed. By carefully selecting the initial potential-temperature profile, the influence of the height and the strength of a capping inversion on the power output of a wind farm is investigated. Results indicate that both the height and the strength have a significant effect on the boundary layer flow, and that the height of the neutral boundary layer is effectively controlled by the capping inversion. In addition, it is shown that the vertical entrainment rate decreases for increasing inversion strength or height. In our infinite wind-farm simulations, varying the inversion characteristics leads to differences in power extraction on the order of 13% ± 0.2% (for increasing the strength from 2.5 to 10 K), and 31% ± 0.4% (for increasing the height from 500 to 1500 m). A detailed analysis of the mean kinetic-energy equation is included, showing that the variation in power extraction originates from the work done by the driving pressure gradient related to the boundary layer height and the geostrophic angle, while entrainment of kinetic energy from the free atmosphere does not play a significant role. Also, the effect of inversion strength on power extraction is energetically not related to different amounts of energy entrained, but explained by a difference in boundary layer growth, leading to higher boundary layers for lower inversion strengths. We further present a simple analytical model that allows to obtain wind-farm power output and driving power for the fully developed regime as function of Rossby number and boundary layer height.
Origin of the enhanced piezoelectric thermal stability in BiScO3-PbTiO3 single crystals
Authors: Kong Lingping , Liu Gang , Zhang Shujun , Yang Wenge
Published: June 2015

BiScO3-PbTiO3 single crystals were reported to possess high piezoelectric coefficient of 1200 pC/N and Curie temperature of >400 °C, exhibiting excellent thermal stability of properties up to 350 °C. However, the origin of the thermal stability is yet unclear. In this research, high resolution synchrotron-based technique was used to study the temperature driven structural evolution in BiScO3-PbTiO3 system, where two competing symmetries and local distortion were observed, accounting for the high piezoelectric activity. A strong correlation between thermal stability of structure and temperature-dependent properties was established, which will benefit the design of ferroelectric materials with broad temperature usage range.
Plasma absorption evidence via chirped pulse spectral transmission measurements
Authors: Jedrkiewicz Ottavia , Minardi Stefano , Couairon Arnaud , Jukna Vytautas , Selva Marco , Di Trapani Paolo
Published: June 2015

This work aims at highlighting the plasma generation dynamics and absorption when a Bessel beam propagates in glass. We developed a simple diagnostics allowing us to retrieve clear indications of the formation of the plasma in the material, thanks to transmission measurements in the angular and wavelength domains. This technique featured by the use of a single chirped pulse having the role of pump and probe simultaneously leads to results showing the plasma nonlinear absorption effect on the trailing part of the pulse, thanks to the spectral-temporal correspondence in the measured signal, which is also confirmed by numerical simulations.
Imaging the equilibrium state and magnetization dynamics of partially built hard disk write heads
Authors: Valkass R. A. J. , Yu W. , Shelford L. R. , Keatley P. S. , Loughran T. H. J. , Hicken R. J. , Cavill S. A. , van der Laan G. , Dhesi S. S. , Bashir M. A. , Gubbins M. A. , Czoschke P. J. , Lopusnik R.
Published: June 2015

Four different designs of partially built hard disk write heads with a yoke comprising four repeats of NiFe (1 nm)/CoFe (50 nm) were studied by both x-ray photoemission electron microscopy (XPEEM) and time-resolved scanning Kerr microscopy (TRSKM). These techniques were used to investigate the static equilibrium domain configuration and the magnetodynamic response across the entire structure, respectively. Simulations and previous TRSKM studies have made proposals for the equilibrium domain configuration of similar structures, but no direct observation of the equilibrium state of the writers has yet been made. In this study, static XPEEM images of the equilibrium state of writer structures were acquired using x-ray magnetic circular dichroism as the contrast mechanism. These images suggest that the crystalline anisotropy dominates the equilibrium state domain configuration, but competition with shape anisotropy ultimately determines the stability of the equilibrium state. Dynamic TRSKM images were acquired from nominally identical devices. These images suggest that a longer confluence region may hinder flux conduction from the yoke into the pole tip: the shorter confluence region exhibits clear flux beaming along the symmetry axis, whereas the longer confluence region causes flux to conduct along one edge of the writer. The observed variations in dynamic response agree well with the differences in the equilibrium magnetization configuration visible in the XPEEM images, confirming that minor variations in the geometric design of the writer structure can have significant effects on the process of flux beaming.