bluuebunny/crossref_metadata_2025 huggingface dataset:
Phononic Structure Engineering: the Realization of Einstein Rattling in Calcium Cobaltate for the Suppression of Thermal Conductivity
Authors: Tian Ruoming , Kearley Gordon J. , Yu Dehong , Ling Chris D. , Pham Anh , Embs Jan P. , Shoko Elvis , Li Sean
Published: July 2016

Phonons in condensed matter materials transmit energy through atomic lattices as coherent vibrational waves. Like electronic and photonic properties, an improved understanding of phononic properties is essential for the development of functional materials, including thermoelectric materials. Recently, an Einstein rattling mode was found in thermoelectric material Na0.8CoO2, due to the large displacement of Na between the [CoO2] layers. In this work, we have realized a different type of rattler in another thermoelectric material Ca3Co4O9 by chemical doping, which possesses the same [CoO2] layer as Na0.8CoO2. It remarkably suppressed the thermal conductivity while enhancing its electrical conductivity. This new type of rattler was investigated by inelastic neutron scattering experiments in conjunction with ab-initio molecular dynamics simulations. We found that the large mass of dopant rather than the large displacement is responsible for such rattling in present study, which is fundamentally different from skutterudites, clathrates as well as Na analogue. We have also tentatively studied the phonon band structure of this material by DFT lattice dynamics simulation, showing the relative contribution to phonons in the distinct layers of Ca3Co4O9.
Early intramedullary nailing of femoral shaft fracture on outcomes in patients with severe chest injury: A meta-analysis
Authors: Jiang Meng , Li Changli , Yi Chengla , Tang Shaotao
Published: July 2016

Early intramedullary nailing (IMN) within the first 24 hours for multiply injured patients with femoral fracture and concomitant severe chest injury is still controversial. This review aimed to investigate the association between early IMN and pulmonary complications in such patients. We searched the literature up to Jan 2016 in the main electronic databases (PubMed, Web of Science, Cochrane library databases) to identify eligible studies. Data were extracted and analyzed using a Mantel–Haenszel method with random-effects model to estimate pooled odds ratio (OR) and 95% confidence intervals (CIs). Seven retrospective cohort studies were identified eventually. The pooled estimates demonstrated that the application of early IMN did not significantly increase the risk of adult respiratory distress syndrome (ARDS) (OR, 0.65; 95% CI: 0.38–1.13), mortality (OR, 0.79; 95% CI: 0.43–1.47), pneumonia (OR, 0.92; 95% CI: 0.55–1.54), multiple organ failure (MOF) (OR, 0.87; 95% CI: 0.45–1.71) and pulmonary embolism (OR, 1.81; 95% CI: 0.28–11.83). In subgroup analysis according to the type of IMN (reamed or undreamed), we did not find any significant difference either. Our results indicated that early IMN of femoral shaft fracture was not associated with increased rates of pulmonary complications in severe chest-injured patients.
Fabrication of a turbid optofluidic phantom device with tunable μa and μ′s to simulate cutaneous vascular perfusion
Authors: Chen Chen , Ahmed Midhat , Häfner Tom , Klämpfl Florian , Stelzle Florian , Schmidt Michael
Published: July 2016

Microfluidic devices are oftenly used to calibrate the imaging reconstruction, because they simulate the morphology of microvasculature. However, for lack of optical properties in microfluidics, the functional recovery of oximetry information cannot be verified. In this work, we describe the fabrication of a novel turbid optofluidic tissue phantom. It is designed to mimic the vascular perfusion and the turbid nature of cutaneous tissue. This phantom contains an interior hollow microfluidic structure with a diameter of ϕave = 50 μm. The microfluidic structure includes the geometry of an inlet, a river-like assay and an outlet. This structure can be perfused by hemoglobin solution to mimic the cutaneous micro-circulation. The multiple-layered phantom matrices exhibit the representative optical parameters of human skin cutis, namely the absorption coefficient μa and the reduced scattering coefficient "Equation missing". The geometry of the generated microfluidic structure is investigated by using Spectral-Domain Optical Coherence Tomography. This optofluidic phantom bridges the gap between tissue equivalent phantoms and Lab-On-Chip devices. Perspectively, this device can be used to calibrate a variety of optical angiographic imaging approaches.
Dielectric Huygens’ Metasurface for High-Efficiency Hologram Operating in Transmission Mode
Authors: Zhao Wenyu , Jiang Huan , Liu Bingyi , Song Jie , Jiang Yongyuan , Tang Chengchun , Li Junjie
Published: July 2016

Conventional metasurface holograms relying on metal antennas for phase manipulation suffer from strong Ohmic loss and incomplete polarization conversion. The efficiency is limited to rather small values when operating in transmission mode. Here, we implement a high-efficiency transmissive metasurface hologram by leveraging the recently developed Huygens’ metasurface to construct an electric and magnetic sheet with a transmission efficiency up to 86% and optical efficiency of 23.6%. The high-efficiency originates from the simultaneous excitations of the Mie-type electric and magnetic dipole resonances in the meta-atoms composed of silicon nanodisks. Our hologram shows high fidelity over a wide spectral range and promises to be an outstanding alternative for display applications.
15q13.3 homozygous knockout mouse model display epilepsy-, autism- and schizophrenia-related phenotypes
Authors: Forsingdal A , Fejgin K , Nielsen V , Werge T , Nielsen J
Published: July 2016

The 15q13.3 microdeletion syndrome is caused by a 1.5-MB hemizygous microdeletion located on 15q13.3 affecting seven genes: FAN1; MTMR10; TRPM1; miR-211; KLF13; OTUD7A; and CHRNA7. The 15q13.3 microdeletion increases the risk of intellectual disability, epilepsy, autism spectrum disorder and schizophrenia, though the clinical profile varies considerably. Two mouse models of this syndrome, with hemizygous deletion of the orthologous region in the murine genome, have recently been shown to recapitulate a number of the behavioral and physiological deficits that characterize the human condition. Still, little is known of the underlying biological mechanisms. Eleven human cases with homozygous deletion of the 15q13.3 region have been reported, all with severe functional and physiological impairments. We therefore hypothesized that a 15q13.3 homozygous knockout would confer more pronounced behavioral and physiological deficits in mice than the 15q13.3 hemizygous deletion. Here we report the characterization of a 15q13.3 knockout mouse. We observed marked deficits including altered seizure susceptibility, autistic behavior-related phenotypes, and auditory sensory processing. Several of these deficits, albeit less pronounced, were also found in the 15q13.3 hemizygous littermates indicating a gene-dosage dependency. Our findings strongly indicate that studies of the hemi- and homozygous 15q13.3 mouse strains will facilitate understanding of the biological mechanisms of severe mental disorders.
Gas-phase microsolvation of ubiquitin: investigation of crown ether complexation sites using ion mobility-mass spectrometry
Authors: Göth Melanie , Lermyte Frederik , Schmitt Xiao Jakob , Warnke Stephan , von Helden Gert , Sobott Frank , Pagel Kevin
Published: July 2016

The influence of side chain to backbone interactions on the gas-phase structure of ubiquitin and ubiquitin lysine-to-arginine mutants was analysed.
Ultrasensitive-electrochemical sensor for the detection of luteolin in Chrysanthemums and Peanut shells using an Au/Pd/reduced graphene oxide nanofilm
Authors: Huang Qitong , Lin Xiaofeng , Lin Changqing , Zhang Yong , Zhang Hanqiang , Hu Shirong , Wei Chan , Tong Qing-Xiao
Published: July 2016

In this study, a rapid and ultrasensitive luteolin sensor has been developed based on an Au/Pd/reduced graphene oxide (Au/Pd/rGO) nanofilm modified glassy carbon electrode (GCE).
Determination of the flavours and marked ages of rice wines using a taste sensing system combined with the Weber–Fechner law and chemometric methods
Authors: Wei ZhenBo , Wang Jun , Cui ShaoQing , Wang Yongwei
Published: July 2016

A taste sensing system was used to determine the marked ages and flavours of rice wines.
A solo fluorogenic probe for the real-time sensing of SO32−and SO42−/HSO4−in aqueous medium and live cells by distinct turn-on emission signals
Authors: Samanta Soham , Dey Poulomi , Ramesh Aiyagari , Das Gopal
Published: July 2016

A fluorogenic probe (L) rendered rapid and differential turn-on responses to SO32−and SO42−/HSO4−in aqueous medium.
One-dimensional self-assembly of perylene-diimide dyes by unidirectional transit of zeolite channel openings
Authors: Tabacchi Gloria , Calzaferri Gion , Fois Ettore
Published: July 2016

Correlated host–guest motions help bulky molecules to enter pores smaller than their size.
Imaging the surface morphology, chemistry and conductivity of LiNi1/3Fe1/3Mn4/3O4 crystalline facets using scanning transmission X-ray microscopy
Authors: Zhou Jigang , Wang Jian , Cutler Jeffrey , Hu Enyuan , Yang Xiao-Qing
Published: July 2016

Scanning transmission X-ray microscopy (STXM) using the X-ray fluorescence mode has been employed to elucidate the chemical structures at Ni, Fe, Mn and O sites from the (111) and (100) facets of micron-sized LiNi1/3Fe1/3Mn4/3O4 energy material particles.
Excited-state torsional relaxation dynamics of meso–meso directly linked corrole dimers: importance of linking position
Authors: Park Kyu Hyung , Ooi Shota , Kim Taeyeon , Tanaka Takayuki , Osuka Atsuhiro , Kim Dongho
Published: July 2016

The effect of linking position on the excited-state dynamics of meso-meso directly linked corrole dimers is explored.
Effect of long-range interactions on nanoparticle-induced aggregation
Authors: Jeżewski Wojciech
Published: July 2016

The process of attaching liquid media molecules to dispersed nanoparticles is studied by numerically investigating the time evolution of the size distribution of the emerging aggregates.
Structure–antiproliferative activity studies onl-proline- and homoproline-4-N-pyrrolidine-3-thiosemicarbazone hybrids and their nickel(ii), palladium(ii) and copper(ii) complexes
Authors: Dobrova Aliona , Platzer Sonja , Bacher Felix , Milunovic Miljan N. M. , Dobrov Anatolie , Spengler Gabriella , Enyedy Éva A. , Novitchi Ghenadie , Arion Vladimir B.
Published: July 2016

The antiproliferative activities of two new thiosemicarbazones as proligands and their NiII, PdII, and CuIIcomplexes in cancer cells are reported in this paper.
Correction: Encapsulating V2O5 into carbon nanotubes enables the synthesis of flexible high-performance lithium ion batteries
Authors: Kong Debin , Li Xianglong , Zhang Yunbo , Hai Xiao , Bin Wang Bin Wang , Qiu Xiongying , Song Qi , Yang Quan-Hong , Zhi Linjie
Published: July 2016

Correction for ‘Encapsulating V2O5 into carbon nanotubes enables the synthesis of flexible high-performance lithium ion batteries’ by Debin Kong et al., Energy Environ. Sci., 2016, 9, 906–911.
Optical anisotropy and sign reversal in layer-by-layer assembled films from chiral nanoparticles
Authors: Liang Zhumei , Bernardino Kalil , Han Jishu , Zhou Yunlong , Sun Kai , de Moura André F. , Kotov Nicholas A.
Published: July 2016

Chiral anisotropy and related optical effects at the nanoscale represent some of the most dynamic areas of nanomaterials today. Translation of optical activity of chiral semiconductor and metallic nanoparticles (NPs) into optoelectronic devices requires preparation of thin films from chiral NPs on both flat and curved surfaces. In this paper we demonstrate that chiral NP films can be made via layer-by-layer assembly (LBL) using negatively charged chiral CdS NPs, stabilized by d- and l-cysteine and positively charged polyelectrolytes, as building blocks. LBL coatings from NPs combine simplicity of preparation and strong optical activity. Circular extinction measurements using circular dichroism instruments indicate that the film possess four chiroptical bands at 280, 320, 350, and 390 nm. The latter two bands at 390 and 350 nm are associated with the band gap transitions (chiral excitons), while the former two are attributed to transitions involving surface ligands. When NPs are assembled in LBL films, the rotatory activity and the sign for circular extinction associated with the electronic transition in the inorganic core of the NPs is conserved. However, this is not true for circular extinction bands at short wavelengths: the sign of the rotatory optical activity is reversed. This effect is attributed to the change of the conformation of surface ligands in the polyelectrolyte matrix, which was confirmed both by semi-empirical and density functional (DFT) quantum mechanical calculations. Circular dichroism spectra calculated using a DFT algorithm closely match the experimental spectra of CdS NPs. These findings indicate that the spectroscopic methods sensitive to chirality of the surface ligands can be used to investigate fine structural changes in the surface layer of nanocolloids. Strong rotatory optical activity of nanostructured semiconductor films opens the possibilities for new polarization-based optical devices.
Blackberry, raspberry and black raspberry polyphenol extracts attenuate angiotensin II-induced senescence in vascular smooth muscle cells
Authors: Feresin Rafaela G. , Huang Jingwen , Klarich DawnKylee S. , Zhao Yitong , Pourafshar Shirin , Arjmandi Bahram H. , Salazar Gloria
Published: July 2016

Blackberry, raspberry and black raspberry polyphenols reduce angiotensin II-induced oxidative stress and senescence of vascular smooth muscle cells.
Role of phytochemicals in the inhibition of epithelial–mesenchymal transition in cancer metastasis
Authors: Kim Eun-Kyung , Choi Eun-Ju , Debnath Trishna
Published: July 2016

Epithelial–mesenchymal transition (EMT) development is controlled by several signaling pathways including Hedgehog, Wnt, fibroblast growth factors (FGF), hepatocyte growth factor/scatter factor (HGF),etc. Phytochemicals is very promising therapeutic candidate that inhibit the progression of EMT by inhibiting the signaling pathways.
New generation of camptothecin derivatives spontaneously alkylating DNA
Authors: Naumczuk Beata , Wiktorska Katarzyna , Lubelska Katarzyna , Kawęcki Robert , Bocian Wojciech , Bednarek Elżbieta , Sitkowski Jerzy , Chilmonczyk Zdzisław , Kozerski Lech
Published: July 2016

The IC50 values of new derivatives 2(a–e) for blood and lung cancer cells are comparable to SN38, and a few orders of magnitude higher than for irinotecan.
Selective modification of the metal coordination environment in heavy alkaline–earth iodide complexes
Authors: Fitts Lacey S. , Bierschenk Eric J. , Hanusa Timothy P. , Rheingold Arnold L. , Pink Maren , Young Victor G.
Published: July 2016

The controlled formation of group 2 coordination complexes involves issues of metal acidity, ligand basicity, solvent effects, and steric pressure.
2D nanostructures for water purification: graphene and beyond
Authors: Dervin Saoirse , Dionysiou Dionysios D. , Pillai Suresh C.
Published: July 2016

Owing to their atomically thin structure, large surface area and mechanical strength, 2D nanoporous materials are considered to be suitable alternatives for existing desalination and water purification membrane materials.
Enantioselective isothiourea-catalysed trans-dihydropyridinone synthesis using saccharin-derived ketimines: scope and limitations
Authors: Stark Daniel G. , Young Claire M. , O'Riordan Timothy J. C. , Slawin Alexandra. M. Z. , Smith Andrew D.
Published: July 2016

The catalytic enantioselective synthesis of a range of trans-dihydropyridinones from aryl-, heteroaryl- and alkenylacetic acids and saccharin-derived ketimines with good to excellent stereocontrol (15 examples, up to >95 : 5 dr, up to >99 : 1 er) is reported.
Rh-catalysed asymmetric conjugate addition of boronic acids to nitroalkenes employing a P-chiral P,π-hybrid ligand
Authors: Sieber Joshua D. , Rivalti Daniel , Herbage Melissa A. , Masters James T. , Fandrick Keith R. , Fandrick Daniel R. , Haddad Nizar , Lee Heewon , Yee Nathan K. , Gupton B. Frank , Senanayake Chris H.
Published: July 2016

A P-chiral P,π-hybrid ligand was applied to the asymmetric conjugate addition of aryl boronic acids to β-substituted nitroalkenes.
Supported lipid bilayer membrane arrays on micro-patterned ITO electrodes
Authors: Wang Xuejing , Zhang Ying , Bi Hongmei , Han Xiaojun
Published: July 2016

Lipid bilayer arrays were formed on micropatterned ITO electrodes. With this bilayer array platform both the fluorescence microscopy and electrochemical detection can be realized to explore the biophysical properties of cell membrane.
Abuse tolerance behavior of layered oxide-based Li-ion battery during overcharge and over-discharge
Authors: Qian Kun , Li Yiyang , He Yan-Bing , Liu Dongqing , Zheng Yong , Luo Dan , Li Baohua , Kang Feiyu
Published: July 2016

The main reason for the degradation of slightly overcharged NCM/graphite full cells was found to be the unstable crystal structure of the NCM material at a relatively high delithiation state.
A novel α-aminophosphonic acid-modified acrylamide-based hydrophobic associating copolymer with superb water solubility for enhanced oil recovery
Authors: Gou Shaohua , Zhang Qin , Yang Cheng , Li Qing , Xu Shuhui , Wu Yuanpeng , Guo Qipeng
Published: July 2016

Here we report a novel α-aminophosphonic acid-modified acrylamide-based hydrophobic associating copolymer. The copolymer exhibits significant potential as an enhanced oil recovery chemical for high-temperature and high-mineralization oilfields.
Efficient energy transfer in ethynyl bridged corrole–BODIPY dyads
Authors: Yan Yu , Wu Fan , Qin Jiawei , Xu Haijun , Shi Maohu , Zhou Jingfeng , Mack John , Fomo Gertrude , Nyokong Tebello , Shen Zhen
Published: July 2016

Corrole–BODIPY dyads bridged by ethynyl linkages have been synthesized in high yield. The efficiency and direction of energy transfer has been found to depend on the number of corrole rings and their connection position on the BODIPY core.
Solvation, rotational relaxation and fluorescence correlation spectroscopic study on ionic liquid-in-oil microemulsions containing triple-chain surface active ionic liquids (SAILs)
Authors: Banerjee Chiranjib , Kundu Niloy , Roy Arpita , Banik Debasis , Halder Mintu , Sarkar Nilmoni
Published: July 2016

In this article, solvation dynamics and rotational relaxation approaches have been applied to explore the microheterogeneity of surface active ionic liquid (SAIL) containing microemulsions, i.e. [P13][Tf2N] or [N3111][Tf2N]/[BHD][AOT]/[IPM].
Electrocatalytic performances of multi-walled carbon nanotubes chemically modified by metal phthalocyanines in Li/SOCl2batteries
Authors: Yang Weixing , Zhang Ronglan , Luo Kai , Zhang Weiping , Zhao Jianshe
Published: July 2016

​A series of metal 2,9,16,23-tetraaminophthalocyanines have been prepared and used to chemically modify fluorinated multi-walled carbon nanotubes (F-MWCNTs). The modified F-MWCNTs can dramatically improve the capacity of the Li/SOCl2battery.
Synthesis and evaluation of new chromene based [1,8]naphthyridines derivatives as potential antimicrobial agents
Authors: Gohil Jayvirsinh D. , Patel Haresh B. , Patel Manish P.
Published: July 2016

Novel chromeno[4,3-f][1,8]naphthyridines derivatives were prepared by multicomponent reaction between 2-((sub)amino)quinoline-3-carbaldehyde 1a–f/2a–f, ethyl 2-cyanoacetate 3 and cyclohexane-1,3-dione 4 in ethanol with l-proline as a catalyst.
Nanostructured hybrid NiFeOOH/CNT electrocatalysts for oxygen evolution reaction with low overpotential
Authors: Rong Feng , Zhao Jiao , Yang Qihua , Li Can
Published: July 2016

The OER activity of nanostructured Ni-based LDH can be improved by doping with transition metals, which can be further enhanced by hybridizing with CNT.
Correction: Metal-free C–N bond formations: one-pot synthesis of pyrido[2′,1′:2,3]imidazo[4,5-c]cinnolines, benzo[4′,5′]thiazolo- and thiazolo[2′,3′:2,3]imidazo[4,5-c]cinnolines
Authors: Kandimalla Satheeshkumar Reddy , Sabitha Gowravaram
Published: July 2016

Correction for ‘Metal-free C–N bond formations: one-pot synthesis of pyrido[2′,1′:2,3]imidazo[4,5-c]cinnolines, benzo[4′,5′]thiazolo- and thiazolo[2′,3′:2,3]imidazo[4,5-c]cinnolines’ by Satheeshkumar Reddy Kandimalla et al., RSC Adv., 2016, 6, 67086–67095.
Intradural Intramedullary Primary Spinal Melanocytoma: A Rare Case Report
Authors: Acharya Shankar , Kalra K. L. , Chahal Rupinder , Ganesan Sudhir
Published: July 2016

Spinal melanocytomas are rare pigmented tumors of the central nervous system commonly affecting females in their fifth decades. It has been reported in various locations with intradural intramedullary being the rarest. Patients can present with varied symptomatology from mild backache to frank myelopathy. Here we report a case of 34-year-old man with no medical comorbidities with vague backache associated with numbness of anterior aspect of right thigh for 1 year aggravated by activities and relieved by rest. His neurologic examination revealed normal power and sensation in both lower limbs except for decreased temperature sensation in right L2 dermatome. MRI of dorsolumbar spine revealed a well-defined lesion that was hyperintense in T1- and hypointense in T2-weighted image at D11–12 region with uniform bright enhancement in gadolinium-enhanced T1 image. The patient underwent laminectomy of D11 and D12, and an en bloc excision was done. Diagnosis of primary intradural intramedullary melanocytoma was made from histopathologic examination. Spinal melanocytomas should be considered as a differential diagnosis for intradural space-occupying lesions. MRI remains the investigation of choice for diagnosis, but histopathologic examination is required to confirm and differentiate from other pigmented tumors and malignant melanomas. Total surgical excision of the tumor remains the standard treatment with radiotherapy reserved for cases of incomplete excision and recurrences.
Dielectrophoretic- and electrohydrodynamic-driven translational motion of a liquid column in transverse electric fields
Authors: Esmaeeli Asghar
Published: July 2016

Computer simulations are performed to study translational motion and deformation of a liquid column or jet, in a plane perpendicular to its axis, due to a transverse electric field. A front tracking/finite difference scheme is used in conjunction with the Taylor-Melcher leaky dielectric theory to solve the governing equations. The column is confined within a rectangular channel, wall-bounded in the vertical direction and periodic in the horizontal direction. It is shown that perfect dielectric columns move toward electrode wall of shorter initial distance, but the leaky dielectric columns may move toward or away from it, depending on the relative importance of the ratios (drop fluid to suspending fluid) of their electric permittivity and conductivity. Furthermore, the degree of interface deformation might increase or decrease with the initial separation distance from the shorter electrode wall due to the same factor. Scaling arguments are used to discern the correlation between the translational velocity and the initial separation distance from the electrodes.
Infrared absorption spectrum of the simplest deuterated Criegee intermediate CD2OO
Authors: Huang Yu-Hsuan , Nishimura Yoshifumi , Witek Henryk A. , Lee Yuan-Pern
Published: July 2016

We report a transient infrared (IR) absorption spectrum of the simplest deuterated Criegee intermediate CD2OO recorded using a step-scan Fourier-transform spectrometer coupled with a multipass absorption cell. CD2OO was produced from photolysis of flowing mixtures of CD2I2, N2, and O2 (13 or 87 Torr) with laser light at 308 nm. The recorded spectrum shows close structural similarity with the spectrum of CH2OO reported previously [Y.-T. Su et al., Science 340, 174 (2013)]. The four bands observed at 852, 1017, 1054, and 1318 cm−1 are assigned to the OO stretching mode, two distinct in-plane OCD bending modes, and the CO stretching mode of CD2OO, respectively, according to vibrational wavenumbers, IR intensities, rotational contours, and deuterium-isotopic shifts predicted with extensive quantum-chemical calculations. The CO-stretching mode of CD2OO at 1318 cm−1 is blue shifted from the corresponding band of CH2OO at 1286 cm−1; this can be explained by a mechanism based on mode mixing and isotope substitution. A band near 936 cm−1, observed only at higher pressure (87 Torr), is tentatively assigned to the CD2 wagging mode of CD2IOO.
Structural, optical, and electrical properties of SmNbO4
Authors: Nico C. , Soares M. R. N. , Costa F. M. , Monteiro T. , Graça M. P. F.
Published: July 2016

Rare-earth orthoniobates constitute a class of materials that has been exploited due to their interesting physical properties depending on the lanthanide element. Besides paramagnetism, ferroelasticity, and negative compressibility, these materials are known by their interesting optical properties and mixed types of conduction processes (protonic, ionic, and electronic). In this work, two types of SmNbO4 samples were studied: polycrystalline samples, prepared by a sol-gel route using the Pechini method, and single crystalline fibres grown by the Laser Floating Zone technique. These samples were structurally characterized based on powder and single-crystal X-ray diffraction studies. A metastable tetragonal phase, stabilized by grain size, was identified in the synthesized powders. After a sintering process of such powders, a single monoclinic phase was obtained. Complementarily, scanning electron microscopy and Raman spectroscopy analyses were performed to these samples. Photoluminescence and photoluminescence excitation spectroscopic studies allowed identifying more than one optically active centre of the trivalent samarium ion in the analysed material. Impedance spectroscopy measurements have shown a large variation of the ac conductivity as a function of temperature, assigned to a protonic conduction and to native ionic conduction mechanisms.
A uniaxial stress capacitive dilatometer for high-resolution thermal expansion and magnetostriction under multiextreme conditions
Authors: Küchler R. , Stingl C. , Gegenwart P.
Published: July 2016

Thermal expansion and magnetostriction are directional dependent thermodynamic quantities. For the characterization of novel quantum phases of matter, it is required to study materials under multi-extreme conditions, in particular, down to very low temperatures, in very high magnetic fields or under high pressure. We developed a miniaturized capacitive dilatometer suitable for temperatures down to 20 mK and usage in high magnetic fields, which exerts a large spring force between 40 to 75 N on the sample. This corresponds to a uniaxial stress up to 3 kbar for a sample with cross section of (0.5 mm)2. We describe design and performance test of the dilatometer which resolves length changes with high resolution of 0.02 Å at low temperatures. The miniaturized device can be utilized in any standard cryostat, including dilution refrigerators or the commercial physical property measurement system.
Development of a simple model for predicting the spark-induced bubble behavior under different ambient pressures
Authors: Zhang L. C. , Zhu X. L. , Huang Y. F. , Liu Z. , Yan K.
Published: July 2016

In this paper, a simple model was developed to predict the dynamics of a spark-induced bubble under different ambient pressures. This work helps in developing a deep-towed plasma sparker, as the model can predict the dynamics of bubbles subjected to very high ambient pressures (about 20 MPa) which normally are difficult to obtain experimentally. Experimental results indicate that the maximum bubble radius for a fixed discharge energy decreases as a power-law function of the ambient pressure up to 1.0 MPa; the bubble period also decreases quickly with increasing ambient pressure. For a constant value of the ratio of bubble energy to discharge energy, the modeling results for both maximum radius and bubble period are in good agreement with the experimental results. Both sets of results indicate that the bubble period is proportional to the maximum radius under different ambient pressures.
Nonequilibrium simulations of model ionomers in an oscillating electric field
Authors: Ting Christina L. , Sorensen-Unruh Karen E. , Stevens Mark J. , Frischknecht Amalie L.
Published: July 2016

We perform molecular dynamics simulations of a coarse-grained model of ionomer melts in an applied oscillating electric field. The frequency-dependent conductivity and susceptibility are calculated directly from the current density and polarization density, respectively. At high frequencies, we find a peak in the real part of the conductivity due to plasma oscillations of the ions. At lower frequencies, the dynamic response of the ionomers depends on the ionic aggregate morphology in the system, which consists of either percolated or isolated aggregates. We show that the dynamic response of the model ionomers to the applied oscillating field can be understood by comparison with relevant time scales in the systems, obtained from independent calculations.
Asymptotic neutron scattering laws for anomalously diffusing quantum particles
Authors: Kneller Gerald R.
Published: July 2016

The paper deals with a model-free approach to the analysis of quasielastic neutron scattering intensities from anomalously diffusing quantum particles. All quantities are inferred from the asymptotic form of their time-dependent mean square displacements which grow ∝tα, with 0 ≤ α < 2. Confined diffusion (α = 0) is here explicitly included. We discuss in particular the intermediate scattering function for long times and the Fourier spectrum of the velocity autocorrelation function for small frequencies. Quantum effects enter in both cases through the general symmetry properties of quantum time correlation functions. It is shown that the fractional diffusion constant can be expressed by a Green-Kubo type relation involving the real part of the velocity autocorrelation function. The theory is exact in the diffusive regime and at moderate momentum transfers.
Integral cross section measurements and product recoil velocity distributions of Xe2+ + N2 hyperthermal charge-transfer collisions
Authors: Hause Michael L. , Prince Benjamin D. , Bemish Raymond J.
Published: July 2016

Charge exchange from doubly charged rare gas cations to simple diatomics proceeds with a large cross section and results in populations of many vibrational and electronic product states. The charge exchange between Xe2+ and N2, in particular, is known to create N2+ in both the A and B electronic states. In this work, we present integral charge exchange cross section measurements of the Xe2+ + N2 reaction as well as axial recoil velocity distributions of the Xe+ and N2+ product ions for collision energies between 0.3 and 100 eV in the center-of-mass (COM) frame. Total charge-exchange cross sections decrease from 70 Å2 to about 40 Å2 with increasing collision energy through this range. Analysis of the axial velocity distributions indicates that a Xe2+ − N2 complex exists at low collision energies but is absent by 17.6 eV COM. Analysis of the axial velocity distributions reveals evidence for complexes with lifetimes comparable to the rotational period at low collision energies. The velocity distributions are consistent with quasi-resonant single charge transfer at high collision energies.
Multi-frequency force-detected electron spin resonance in the millimeter-wave region up to 150 GHz
Authors: Ohmichi E. , Tokuda Y. , Tabuse R. , Tsubokura D. , Okamoto T. , Ohta H.
Published: July 2016

In this article, a novel technique is developed for multi-frequency force-detected electron spin resonance (ESR) in the millimeter-wave region. We constructed a compact ESR probehead, in which the cantilever bending is sensitively detected by a fiber-optic Fabry-Perot interferometer. With this setup, ESR absorption of diphenyl-picrylhydrazyl radical (<1 μg) was clearly observed at multiple frequencies of up to 150 GHz. We also observed the hyperfine splitting of low-concentration Mn2+ impurities(∼0.2%) in MgO.
Talbot-Lau x-ray deflectometer electron density diagnostic for laser and pulsed power high energy density plasma experiments (invited)
Authors: Valdivia M. P. , Stutman D. , Stoeckl C. , Mileham C. , Begishev I. A. , Theobald W. , Bromage J. , Regan S. P. , Klein S. R. , Muñoz-Cordovez G. , Vescovi M. , Valenzuela-Villaseca V. , Veloso F.
Published: July 2016

Talbot-Lau X-ray deflectometry (TXD) has been developed as an electron density diagnostic for High Energy Density (HED) plasmas. The technique can deliver x-ray refraction, attenuation, elemental composition, and scatter information from a single Moiré image. An 8 keV Talbot-Lau interferometer was deployed using laser and x-pinch backlighters. Grating survival and electron density mapping were demonstrated for 25–29 J, 8–30 ps laser pulses using copper foil targets. Moiré pattern formation and grating survival were also observed using a copper x-pinch driven at 400 kA, ∼1 kA/ns. These results demonstrate the potential of TXD as an electron density diagnostic for HED plasmas.
Plasma characterization using ultraviolet Thomson scattering from ion-acoustic and electron plasma waves (invited)
Authors: Follett R. K. , Delettrez J. A. , Edgell D. H. , Henchen R. J. , Katz J. , Myatt J. F. , Froula D. H.
Published: July 2016

Collective Thomson scattering is a technique for measuring the plasma conditions in laser-plasma experiments. Simultaneous measurements of ion-acoustic and electron plasma-wave spectra were obtained using a 263.25-nm Thomson-scattering probe beam. A fully reflective collection system was used to record light scattered from electron plasma waves at electron densities greater than 1021 cm−3, which produced scattering peaks near 200 nm. An accurate analysis of the experimental Thomson-scattering spectra required accounting for plasma gradients, instrument sensitivity, optical effects, and background radiation. Practical techniques for including these effects when fitting Thomson-scattering spectra are presented and applied to the measured spectra to show the improvements in plasma characterization.
Creating Ruddlesden-Popper phases by hybrid molecular beam epitaxy
Authors: Haislmaier Ryan C. , Stone Greg , Alem Nasim , Engel-Herbert Roman
Published: July 2016

The synthesis of a 50 unit cell thick n = 4 Srn+1TinO3n+1 (Sr5Ti4O13) Ruddlesden-Popper (RP) phase film is demonstrated by sequentially depositing SrO and TiO2 layers in an alternating fashion using hybrid molecular beam epitaxy (MBE), where Ti was supplied using titanium tetraisopropoxide (TTIP). A detailed calibration procedure is outlined for determining the shuttering times to deposit SrO and TiO2 layers with precise monolayer doses using in-situ reflection high energy electron diffraction (RHEED) as feedback. Using optimized Sr and TTIP shuttering times, a fully automated growth of the n = 4 RP phase was carried out over a period of >4.5 h. Very stable RHEED intensity oscillations were observed over the entire growth period. The structural characterization by X-ray diffraction and high resolution transmission electron microscopy revealed that a constant periodicity of four SrTiO3 perovskite unit cell blocks separating the double SrO rocksalt layer was maintained throughout the entire film thickness with a very little amount of planar faults oriented perpendicular to the growth front direction. These results illustrate that hybrid MBE is capable of layer-by-layer growth with atomic level precision and excellent flux stability.
Investigation of structure and magnetic properties of Ru-doped YMnO3
Authors: Dai Y. , Zhang A. M. , Yang L. P. , Gao Z. R. , Wu X. S.
Published: July 2016

A series of polycrystalline YMn1−xRuxO3 (0 ≤ x ≤ 0.2) samples were prepared by traditional solid-state reaction method. Effects of doping on the microstructures and magnetic properties were investigated. Microstructural results reveal that samples crystallize in a single hexagonal structure with P63cm group for x ≤ 0.1. Lattice parameters a, c, and unit-cell volume of YMn1−xRuxO3 are found to increase with doping content, which are ascribed to the larger radius of Ru3+ than that of Mn3+. Weak ferromagnetism is found and is enhanced with increasing doping concentration x. The bond angles of Mn-O3-Mn and Mn-O4-Mn are changed in the opposite trends, which break the Mn-Mn exchange interaction, thus the antiferromagnetic ordering. The MnO5 bipyramid is found to be relieved and the trimerization of Mn ions is weakened. These structural modifications result in the increase of weak ferromagnetism ordering in samples.
Semiclassical states of p-Laplacian equations with a general nonlinearity in critical case
Authors: Zhang Jianjun , Costa David G. , do Ó João Marcos
Published: July 2016

We consider the p-Laplacian problem −εpΔpu+V(x)up−2u=f(u),u∈W1,p(RN), where p ∈ (1, N) and f(s) is of critical growth. In this paper, we construct a single peak solution around an isolated component of the positive local minimum points of V as ε → 0 with a general nonlinearity f. In particular, the monotonicity of f(s)/sp−1 and the so-called Ambrosetti-Rabinowitz condition are not required.
“Half a proton” in the Bogomol’nyi-Prasad-Sommerfield Skyrme model
Authors: Lukács Árpád
Published: July 2016

The BPS Skyrme model is a model containing an SU(2)-valued scalar field, in which a Bogomol’nyi-type inequality can be satisfied by soliton solutions (skyrmions). In this model, the energy density of static configurations is the sum of the square of the topological charge density plus a potential. The topological charge density is nothing else but the pull-back of the Haar measure of the group SU(2) on the physical space by the field configuration. As a consequence, this energy expression has a high degree of symmetry: it is invariant to volume preserving diffeomorphisms both on physical space and on the target space. We demonstrate here that in the BPS Skyrme model such solutions exist that a fraction of its charge and energy densities is localised, and the remaining part can be far away, not interacting with the localised part.
8-band k·p modelling of mid-infrared intersubband absorption in Ge quantum wells
Authors: Paul D. J.
Published: July 2016

The 8-band k·p parameters which include the direct band coupling between the conduction and the valence bands are derived and used to model optical intersubband transitions in Ge quantum well heterostructure material grown on Si substrates. Whilst for Si rich quantum wells the coupling between the conduction bands and valence bands is not important for accurate modelling, the present work demonstrates that the inclusion of such coupling is essential to accurately determine intersubband transitions between hole states in Ge and Ge-rich Si1−xGex quantum wells. This is due to the direct bandgap being far smaller in energy in Ge compared to Si. Compositional bowing parameters for a range of the key modelling input parameters required for Ge/SiGe heterostructures, including the Kane matrix elements, the effective mass of the Γ2′ conduction band, and the Dresselhaus parameters for both 6- and 8-band k·p modelling, have been determined. These have been used to understand valence band intersubband transitions in a range of Ge quantum well intersubband photodetector devices in the mid-infrared wavelength range.
Bandgap measurements and the peculiar splitting of E2H phonon modes of InxAl1-xN nanowires grown by plasma assisted molecular beam epitaxy
Authors: Tangi Malleswararao , Mishra Pawan , Janjua Bilal , Ng Tien Khee , Anjum Dalaver H. , Prabaswara Aditya , Yang Yang , Albadri Abdulrahman M. , Alyamani Ahmed Y. , El-Desouki Munir M. , Ooi Boon S.
Published: July 2016

The dislocation free InxAl1-xN nanowires (NWs) are grown on Si(111) by nitrogen plasma assisted molecular beam epitaxy in the temperature regime of 490 °C–610 °C yielding In composition ranges over 0.50 ≤ x ≤ 0.17. We study the optical properties of these NWs by spectroscopic ellipsometry (SE), photoluminescence, and Raman spectroscopies since they possesses minimal strain with reduced defects comparative to the planar films. The optical bandgap measurements of InxAl1-xN NWs are demonstrated by SE where the absorption edges of the NW samples are evaluated irrespective of substrate transparency. A systematic Stoke shift of 0.04–0.27 eV with increasing x was observed when comparing the micro-photoluminescence spectra with the Tauc plot derived from SE. The micro-Raman spectra in the NWs with x = 0.5 showed two-mode behavior for A1(LO) phonons and single mode behavior for E2H phonons. As for x = 0.17, i.e., high Al content, we observed a peculiar E2H phonon mode splitting. Further, we observe composition dependent frequency shifts. The 77 to 600 K micro-Raman spectroscopy measurements show that both AlN- and InN-like modes of A1(LO) and E2H phonons in InxAl1-xN NWs are redshifted with increasing temperature, similar to that of the binary III group nitride semiconductors. These studies of the optical properties of the technologically important InxAl1-xN nanowires will path the way towards lasers and light-emitting diodes in the wavelength of the ultra-violet and visible range.
Low-noise heterodyne receiver for electron cyclotron emission imaging and microwave imaging reflectometry
Authors: Tobias B. , Domier C. W. , Luhmann N. C. , Luo C. , Mamidanna M. , Phan T. , Pham A.-V. , Wang Y.
Published: July 2016

The critical component enabling electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) to resolve 2D and 3D electron temperature and density perturbations is the heterodyne imaging array that collects and downconverts radiated emission and/or reflected signals (50–150 GHz) to an intermediate frequency (IF) band (e.g. 0.1–18 GHz) that can be transmitted by a shielded coaxial cable for further filtering and detection. New circuitry has been developed for this task, integrating gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs) mounted on a liquid crystal polymer (LCP) substrate. The improved topology significantly increases electromagnetic shielding from out-of-band interference, leads to 10× improvement in the signal-to-noise ratio, and dramatic cost savings through integration. The current design, optimized for reflectometry and edge radiometry on mid-sized tokamaks, has demonstrated >20 dB conversion gain in upper V-band (60-75 GHz). Implementation of the circuit in a multi-channel electron cyclotron emission imaging (ECEI) array will improve the diagnosis of edge-localized modes and fluctuations of the high-confinement, or H-mode, pedestal.
Calibration of scintillation-light filters for neutron time-of-flight spectrometers at the National Ignition Facility
Authors: Sayre D. B. , Barbosa F. , Caggiano J. A. , DiPuccio V. N. , Eckart M. J. , Grim G. P. , Hartouni E. P. , Hatarik R. , Weber F. A.
Published: July 2016

Sixty-four neutral density filters constructed of metal plates with 88 apertures of varying diameter have been radiographed with a soft x-ray source and CCD camera at National Security Technologies, Livermore. An analysis of the radiographs fits the radial dependence of the apertures’ image intensities to sigmoid functions, which can describe the rapidly decreasing intensity towards the apertures’ edges. The fitted image intensities determine the relative attenuation value of each filter. Absolute attenuation values of several imaged filters, measured in situ during calibration experiments, normalize the relative quantities which are now used in analyses of neutron spectrometer data at the National Ignition Facility.
Improved memory characteristics of charge trap memory by employing double layered ZrO2 nanocrystals and inserted Al2O3
Authors: Tang Z. J. , Li R. , Zhang X. W. , Hu D. , Zhao Y. G.
Published: July 2016

The charge trap memory capacitors incorporating a stacked charge trapping layer consisting of double layered ZrO2 nanocrystals (NCs) and inserted Al2O3 have been fabricated and investigated. It is observed that the memory capacitor with stacked trapping layer exhibits a hysteresis window as large as 14.3 V for ±10 V sweeping gate voltage range, faster program/erase speed, improved endurance performance, and good data retention characteristics with smaller extrapolated ten years charge loss at room temperature and 125 °C compared to single layered NCs. The special energy band alignment and the introduced additional traps of double layered ZrO2 NCs and inserted Al2O3 change the trapping and loss behavior of charges, and jointly contribute to the remarkable memory characteristics. Therefore, the memory capacitor with a stacked charge trapping layer is a promising candidate in future nonvolatile charge trap memory device design and application.
The initial value problem for a Novikov system
Authors: Himonas A. Alexandrou , Mantzavinos Dionyssios
Published: July 2016

It is shown that the initial value problem for an integrable Novikov system is well-posed in Sobolev spaces Hs, s > 3/2, in the sense of Hadamard. Furthermore, it is proved that the dependence on initial data is sharp, i.e., the data-to-solution map is continuous but not uniformly continuous. Also, peakon traveling wave solutions are used to prove that the solution map is not uniformly continuous in Hs for s < 3/2.
Long working distance objective lenses for single atom trapping and imaging
Authors: Pritchard J. D. , Isaacs J. A. , Saffman M.
Published: July 2016

We present a pair of optimized objective lenses with long working distances of 117 mm and 65 mm, respectively, that offer diffraction limited performance for both Cs and Rb wavelengths when imaging through standard vacuum windows. The designs utilise standard catalog lens elements to provide a simple and cost-effective solution. Objective 1 provides NA = 0.175 offering 3 μm resolution whilst objective 2 is optimized for high collection efficiency with NA = 0.29 and 1.8 μm resolution. This flexible design can be further extended for use at shorter wavelengths by simply re-optimising the lens separations.
Topological honeycomb magnon Hall effect: A calculation of thermal Hall conductivity of magnetic spin excitations
Authors: Owerre S. A.
Published: July 2016

Quite recently, the magnon Hall effect of spin excitations has been observed experimentally on the kagome and pyrochlore lattices. The thermal Hall conductivity κxy changes sign as a function of magnetic field or temperature on the kagome lattice, and κxy changes sign upon reversing the sign of the magnetic field on the pyrochlore lattice. Motivated by these recent exciting experimental observations, we theoretically propose a simple realization of the magnon Hall effect in a two-band model on the honeycomb lattice. The magnon Hall effect of spin excitations arises in the usual way via the breaking of inversion symmetry of the lattice, however, by a next-nearest-neighbour Dzyaloshinsky-Moriya interaction. We find that κxy has a fixed sign for all parameter regimes considered. These results are in contrast to the Lieb, kagome, and pyrochlore lattices. We further show that the low-temperature dependence on the magnon Hall conductivity follows a T2 law, as opposed to the kagome and pyrochlore lattices. These results suggest an experimental procedure to measure thermal Hall conductivity within a class of 2D honeycomb quantum magnets and ultracold atoms trapped in a honeycomb optical lattice.