bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasma technology – a novel solution for CO2 conversion?
Authors: Snoeckx Ramses , Bogaerts Annemie
Published: August 2017

Plasma technology as a potential breakthrough technology for the economic conversion of CO2 into value-added chemicals and fuels.
Screening of histone deacetylase 1 inhibitors in natural products by capillary electrophoresis
Authors: Zhang Yanmei , Li Feng , Kang Jingwu
Published: August 2017

A method for the screening of histone deacetylase 1 (HDAC1) inhibitors in natural products by using capillary electrophoresis (CE) coupled with laser induced fluorescence (LIF) detection was developed.
Simple method for the quantitative analysis of thin copolymer films on substrates by infrared spectroscopy using direct calibration
Authors: Tazreiter Martin , Christian Paul , Schennach Robert , Grießer Thomas , Coclite Anna Maria
Published: August 2017

Automated baseline estimation followed by least squares fitting of copolymer spectrum allows quantification in terms of comonomer volume fraction.
A fluorescence-enhanced probe for rapid detection of formaldehyde and its application for cell imaging
Authors: Wu Feng , Zhang Yue , Huang Lei , Xu Dan , Wang Hongying
Published: August 2017

An anthracene carboxyimide-based fluorescent probe was developed for rapid detection of formaldehyde in living cells with high sensitivity and selectivity.
Prevention of aerobic oxidation of copper nanoparticles by anti-galvanic alloying: gold versus silver
Authors: Liu Xiang , Ruiz Jaime , Astruc Didier
Published: August 2017

Alloying CuNPs with AuNPs or AgNPs followed by exposure to air only leads to Cu(0) oxidation to Cu(i) in AgCu alloyed NPs, whereas Cu(0) is not oxidized in AuCu alloyed NPs in which Au(i) forms.
Closed-shell paramagnetic porphyrinoids
Authors: Valiev Rashid R. , Fliegl Heike , Sundholm Dage
Published: August 2017

Magnetizabilities and magnetically induced ring-current strength susceptibilities have been calculated at the Hartree–Fock, density functional theory and second order Møller–Plesset levels for a number of antiaromatic closed-shell carbaporphyrins, carbathiaporphyrins and isophlorins.
How does graphene grow on complex 3D morphologies?
Authors: Chin H. T. , Shih C. H. , Hsieh Y. P. , Ting C. C. , Aoh J. N. , Hofmann M.
Published: August 2017

Quantitative characterization of the graphene growth process under varying confinement shows a smooth transition between molecular-flow and free-flow transport.
Investigation of superconductivity in compressed vanadium hydrides
Authors: Zhuang Quan , Jin Xilian , Lv Qianqian , Li Ying , Shao Ziji , Liu Zhao , Li Xin , Zhang Huadi , Meng Xing , Bao Kuo , Cui Tian
Published: August 2017

The mechanism for superconductivity is analyzed based on the trends of λ, 〈I2〉, N(εF), and 〈ω2〉1/2 as a function of pressure.
Catalytic CVD synthesis of boron nitride and carbon nanomaterials – synergies between experiment and theory
Authors: McLean Ben , Eveleens Clothilde A. , Mitchell Izaac , Webber Grant B. , Page Alister J.
Published: August 2017

We present a perspective demonstrating the importance of synergy between experiment and theory for modern nanomaterial synthesis.
Design and construction of a bifunctional magnetically recyclable 3D CoMn2O4/CF hybrid as an adsorptive photocatalyst for the effective removal of contaminants
Authors: Zheng Jianhua , Hu Yandong , Zhang Lei
Published: August 2017

Herein, a magnetic microsphere CoMn2O4 (MS-CoMn2O4) with a 3D architecture was constructed directly on cellulose fiber (CF) substrates from wastepaper by a solvothermal synthesis method with further calcination treatment.
Hydrophobic fluorine mediated switching of the hydrogen bonding site as well as orientation of water molecules in the aqueous mixture of monofluoroethanol: IR, molecular dynamics and quantum chemical studies
Authors: Mondal Saptarsi , Biswas Biswajit , Nandy Tonima , Singh Prashant Chandra
Published: August 2017

Fluorination of ethanol changes orientation of water in its aqueous mixture.
Potential color tunable Sr3LaNa(PO4)3F:Eu2+/Tb3+/Mn2+phosphor induced by Eu2+→ Tb3+and Tb3+→ Mn2+energy transfer for WLEDs
Authors: Jiao Mengmeng , Yang Chuanlu , Li Yalin , Wang Dongxu , You Hongpeng
Published: August 2017

Sr3LaNa(PO4)3F:Eu2+,Tb3+and Sr3LaNa(PO4)3F:Tb3+,Mn2+phosphors with tunable blue-green and green-orange emissions have been obtained utilizing Eu2+→ Tb3+and Tb3+→ Mn2+energy transfers, respectively.
Density functional study on the resistance to sulfur poisoning of Ptx (x = 0, 1, 4 and 8) modified α-Mo2C(0001) surfaces
Authors: Kong Weimeng , Zhang Xilin , Mao Jianjun , Xu Xiaopei , Zhang Yanxing , Yang Zongxian
Published: August 2017

The ability of Mo2C(0001) to resist sulfur poisoning is positively related to the coverage of Pt.
Sensing the framework state and guest molecules in MIL-53(Al) via the electron paramagnetic resonance spectrum of VIV dopant ions
Authors: Nevjestić Irena , Depauw Hannes , Gast Peter , Tack Pieter , Deduytsche Davy , Leus Karen , Van Landeghem Melissa , Goovaerts Etienne , Vincze Laszlo , Detavernier Christophe , Van Der Voort Pascal , Callens Freddy , Vrielinck Henk
Published: August 2017

The EPR spectrum of VIV dopant ions was used to discriminate different states of MIL-53(Al) and to detect oxygen gas.
Plasma-assisted catalytic reforming of toluene to hydrogen rich syngas
Authors: Liu Lina , Wang Qiang , Song Jianwei , Ahmad Shakeel , Yang Xiaoyi , Sun Yifei
Published: August 2017

Ni/ZSM-5 in in-plasma catalysis systems has potential for toluene conversion, syngas formation, and inhibition of undesirable by-products and coke formation.
Strong metal–support interactions between Ni and ZnO particles and their effect on the methanation performance of Ni/ZnO
Authors: Wang Weixing , Li Xuekuan , Zhang Ye , Zhang Rong , Ge Hui , Bi Jicheng , Tang Mingxing
Published: August 2017

Strong metal–support interactions (SMSI) between Ni and ZnO particles and their suppression effect on CO methanation.
Synthesis and characterisation of new tripodal lanthanide complexes and investigation of their optical and magnetic properties
Authors: Craze Alexander R. , Huang Xin-Da , Etchells Isaac , Zheng Li-Min , Bhadbhade Mohan M. , Marjo Christopher E. , Clegg Jack K. , Moore Evan G. , Avdeev Maxim , Lindoy Leonard F. , Li Feng
Published: August 2017

The neutral complexes of type [EuL], [GdL] and [DyL] incorporating a heptadentate tripodal ligand were synthesized and their optical and magnetic properties have been investigated.
Observation of magnetic interactions between localized 4f- and itinerant π-electrons in a single crystal of cationic bisphthalocyanine complexes containing diluted spin centres
Authors: Fukuda Takamitsu , Onodera Shun , Watanabe Hirohito , Shirasaki Kenji , Fuyuhiro Akira , Yamamura Tomoo , Ishikawa Naoto
Published: August 2017

Clear evidence of magnetic interactions between localized 4f- and itinerant π-electrons has been observed in double-decker phthalocyanine crystals.
Direct self-focusing synthesis of monodisperse [Au8(PPh3)7]2+nanoclusters
Authors: Huang Ting , Huang Li , Jiang Yong , Hu Fengchun , Sun Zhihu , Pan Guoqiang , Wei Shiqiang
Published: August 2017

Direct synthesis of atomically monodisperse Au8nanoclustersviathe self-focusing process during NaBH4reduction of Au(PPh3)2Cl.
Fundamental studies of an atmospheric-pressure microwave plasma sustained in nitrogen for atomic emission spectrometry
Authors: Chalyavi Nahid , Doidge Peter S. , Morrison Richard J. S. , Partridge Guthrie B.
Published: August 2017

Fundamental characteristics of a microwave plasma sustained in nitrogen (Agilent 4200 MP-ES) are investigated by a combination of thermochemical modelling and spectroscopic techniques, including Thomson scattering.
Evaluation of the self-absorption reduction of minor elements in laser-induced breakdown spectroscopy assisted with laser-stimulated absorption
Authors: Li Jiaming , Tang Yun , Hao Zhongqi , Zhao Nan , Yang Xinyan , Yu Huiwu , Guo Lianbo , Li Xiangyou , Zeng Xiaoyan , Lu Yongfeng
Published: August 2017

This paper describes the quantitative evaluation of the self-absorption reduction of minor elements in laser-induced breakdown spectroscopy assisted with laser-stimulated absorption.
The solid state structure and environmental polarization effect of a novel asymmetric azine
Authors: Valverde Clodoaldo , Vaz Wesley F. , Custodio Jean M. F. , Duarte Vitor S. , Carvalho-Jr Paulo S. , Figueredo Andreza S. , de Aquino Gilberto L. B. , Baseia Basílio , Napolitano Hamilton B.
Published: August 2017

Extensive solid state characterization of a novel asymmetric azine and its environmental polarization effect is reported.
Competing phenol–imidazole and phenol–phenol interactions in the flexible supramolecular environment of N,N′-bis(3-imidazol-1-ylpropyl)naphthalenediimide causing domain expansion
Authors: Tarai Arup , Baruah Jubaraj B.
Published: August 2017

Spectroscopic and crystallographic studies on cocrystals of N,N′-bis(3-imidazol-1-yl-propyl)naphthalenediimide (L) with a series of phenolic compounds have revealed that competition to form phenol–imidazole and phenol–phenol synthons causes domain expansion.
In situ-generated Co@nitrogen-doped carbon nanotubes derived from MOFs for efficient hydrogen evolution under both alkaline and acidic conditions
Authors: Li Ji-Sen , Du Bing , Lu Zhi-Hua , Meng Qing-Ting , Sha Jing-Quan
Published: August 2017

In situ-generated Co@nitrogen-doped carbon nanotubes derived from metal–organic frameworks were fabricated by a facile method and corresponding HER performances were investigated in detail.
NIR-emissive PEG-b-TCL micelles for breast tumor imaging and minimally invasive pharmacokinetic analysis
Authors: Hofmann Christina L. , O'Sullivan Melanie C. , Detappe Alexandre , Yu Yingjie , Yang Xi , Qi Wei , Landon Chelsea D. , Therien Michael J. , Dewhirst Mark W. , Ghoroghchian P. Peter , Palmer Gregory M.
Published: August 2017

Biodegradable NIR-emissive micelles are used for monitoring biodistribution and pharmacokinetics using minimally invasive imaging based approaches.
Engineering a red emission of copper nanocluster self-assembly architectures by employing aromatic thiols as capping ligands
Authors: Ai Lin , Jiang Wanrun , Liu Zhaoyu , Liu Jiale , Gao Yang , Zou Haoyang , Wu Zhennan , Wang Zhigang , Liu Yi , Zhang Hao , Yang Bai
Published: August 2017

Aromatic thiols are employed as capping ligands to prepare self-assembly architectures of Cu nanoclusters, which generate tunable aggregation-induced emission in the red region.
Translucent, hydrophobic, and mechanically tough aerogels constructed from trimethylsilylated chitosan nanofibers
Authors: Takeshita S. , Yoda S.
Published: August 2017

An ultralight, translucent, non-brittle, and hydrophobic nanofibrous aerogel was prepared for the first time using bio-based chitosan nanofibers.
Tuning hexagonal NaYbF4 nanocrystals down to sub-10 nm for enhanced photon upconversion
Authors: Shi Ruikai , Ling Xincan , Li Xiaona , Zhang Lu , Lu Min , Xie Xiaoji , Huang Ling , Huang Wei
Published: August 2017

Controlled synthesis of sub-10 nm hexagonal NaYbF4 upconversion nanocrystals with enhanced upconversion emission was facilely achieved.
The dendritic effect and magnetic permeability in dendron coated nickel and manganese zinc ferrite nanoparticles
Authors: Jishkariani Davit , Lee Jennifer D. , Yun Hongseok , Paik Taejong , Kikkawa James M. , Kagan Cherie R. , Donnio Bertrand , Murray Christopher B.
Published: August 2017

The collective magnetic properties of nanoparticle (NP) solid films are greatly affected by inter-particle dipole–dipole interactions and therefore the proximity of the neighboring particles.
Three pillared-layered inorganic–organic hybrid polymers with efficient luminescence
Authors: Liu Xi , Zhao Zhen , Wang Chun-Hai , Fu Shan , Huang Kun-Lin
Published: August 2017

Three pillared-layered inorganic–organic hybrid polymers are synthesized via layer diffusion methods, which exhibit efficient luminescence.
New phases of 3d-transition metal–cerium binary compounds: an extensive structural search
Authors: Sun Xiaorui , Lei Yawei , Zhou Rulong , Qu Bingyan , Li Dongdong , Zhang Bo , Zeng Xiao Cheng
Published: August 2017

The phase stabilities, structural features, electronic and mechanical properties of 3d transitional metal–cerium binary compounds were systematically studied.
Development of a fiber-based membraneless hydrogen peroxide fuel cell
Authors: Asadnia Mohsen , Mousavi Ehteshami Seyyed Mohsen , Chan Siew Hwa , Warkiani Majid Ebrahmi
Published: August 2017

Polyvinylidene fluoride (PVDF) electrospun nano-fiber is suggested as the substrate material for developing biocompatible membraneless hydrogen peroxide fuel cells.
Glycerol–water mediated centrifuge controlled green synthesis of oleic acid capped PbS quantum dots for live cell imaging
Authors: Bharathi M. Vijaya , Ghosh Kaustab , Paira Priyankar
Published: August 2017

Glycerol–water mediated green synthesis of PbS quantum dots (QDs) is introduced utilizing distinctive precipitation strategies for bioimaging application.
Nano/microvehicles for efficient delivery and (bio)sensing at the cellular level
Authors: Campuzano S. , Esteban-Fernández de Ávila B. , Yáñez-Sedeño P. , Pingarrón J. M. , Wang J.
Published: August 2017

A perspective review of recent strategies involving the use of nano/microvehicles to address the key challenges associated with delivery and (bio)sensing at the cellular level is presented.
Photocatalytic oxidation of benzene to phenol using dioxygen as an oxygen source and water as an electron source in the presence of a cobalt catalyst
Authors: Han Ji Won , Jung Jieun , Lee Yong-Min , Nam Wonwoo , Fukuzumi Shunichi
Published: August 2017

The present study reports the first example of photocatalytic hydroxylation of benzene with O2 and H2O, both of which are the most green reagents, under visible light irradiation to afford a high turnover number.
Fluorinated molecular beacons as functional DNA nanomolecules for cellular imaging
Authors: Jin Cheng , Fu Ting , Wang Ruowen , Liu Hui , Zou Jianmei , Zhao Zilong , Ye Mao , Zhang Xiaobing , Tan Weihong
Published: August 2017

Molecular beacons (MBs) are simple, but practical, fluorescent nanoprobes widely used to detect small molecules, nucleic acids and proteins.
Cavitation to fracture transition in a soft solid
Authors: Kang Jingtian , Wang Changguo , Cai Shengqiang
Published: August 2017

When large hydrostatic tension is applied onto a soft solid, crack extension can be induced during the cavitating process.
Layered tellurides: stacking faults induce low thermal conductivity in the new In2Ge2Te6 and thermoelectric properties of related compounds
Authors: Lefèvre Robin , Berthebaud David , Lebedev Oleg , Pérez Olivier , Castro Célia , Gascoin Stéphanie , Chateigner Daniel , Gascoin Franck
Published: August 2017

A new ternary layered compound In2Ge2Te6, belonging to the hexatellurogermanate family has been synthesized from the reaction of appropriate amounts of the pure elements at high temperature in sealed silica tubes.
Effect of a sulfur and nitrogen dual-doped Fe–N–S electrocatalyst for the oxygen reduction reaction
Authors: Huang Hsin-Chih , Lin Yu-Chuan , Chang Sun-Tang , Liu Chia-Chi , Wang Kai-Chin , Jhong Huan-Ping , Lee Jyh-Fu , Wang Chen-Hao
Published: August 2017

A new catalyst with a nitrogen and sulfur dual-doped –Fe–N–S– structure shows excellent ORR activity for AEMFCs.
Counterion-tunable n-type conjugated polyelectrolytes for the interface engineering of efficient polymer solar cells
Authors: Chen Zhiming , Hu Zhicheng , Wu Zhihong , Liu Xiang , Jin Yaocheng , Xiao Manjun , Huang Fei , Cao Yong
Published: August 2017

We report a series of counterion-tunable n-type conjugated polyelectrolytes for the interface engineering of polymer solar cells.
Tuning the self-assembly and photophysical properties of bi-1,3,4-thiadiazole derivatives through electron donor–acceptor interactions and their application in OLEDs
Authors: Yadav Abhay Kumar , Pradhan Balaram , Ulla Hidayath , Nath Subrata , De Joydip , Pal Santanu Kumar , Satyanarayan M. N. , Achalkumar Ammathnadu S.
Published: August 2017

Delicate interplay of donor–acceptor interactions in directing the self-assembly and its application.
Temperature-dependent charge transport in solution-processed perovskite solar cells with tunable trap concentration and charge recombination
Authors: Zhang Xuning , Bi Shiqing , Zhou Jiyu , You Shuai , Zhou Huiqiong , Zhang Yuan , Tang Zhiyong
Published: August 2017

Based on control of the perovskite film thickness, we investigate temperature-dependent charge carrier transport, recombination, traps, and solar cell behavior based on methylammonium lead triiodide films.
Unexpected Rearrangement of 2-Bromoaniline under Biphasic Alkylation Conditions
Authors: Barraza Scott , Denmark Scott
Published: August 2017

Alkylation of 2-bromoaniline with benzyl bromide under ostensibly basic N-alkylation conditions resulted in migration of bromine from the 2- to the 4-aryl position. Herein we report our studies to elucidate the mechanism of this rearrangement with the objective of suppressing this unexpected outcome. We find that careful choice of reagents is critical, and that this behavior may be extrapolated to alkylation reactions of electron-rich bromo- and iodoanilines in general.
Passivation of edge states in etched InAs sidewalls
Authors: Mittag Christopher , Karalic Matija , Mueller Susanne , Tschirky Thomas , Wegscheider Werner , Nazarenko Olga , Kovalenko Maksym V. , Ihn Thomas , Ensslin Klaus
Published: August 2017

We investigate different methods of passivating sidewalls of wet etched InAs heterostructures in order to suppress inherent edge conduction that is presumed to occur due to band bending at the surface, leading to charge carrier accumulation. Passivation techniques including sulfur, positively charged compensation dopants, and plasma enhanced chemical vapor deposition of SiNx do not show an improvement. Surprisingly, atomic layer deposition of Al2O3 leads to an increase in the edge resistivity of more than an order of magnitude. While the mechanism behind this change is not fully understood, possible reasons are suggested.
All dielectric metamaterial loaded tunable plasmonic waveguide
Authors: Sifat Abid Anjum , Sayem Ayed Al , Sajeeb M. Mahmudul Hasan
Published: August 2017

In this article, a 2D plasmonic waveguide loaded with all dielectric anisotropic metamaterial, consisting of alternative layers of Si-SiO2, has been theoretically proposed and numerically analyzed. Main characteristics of waveguide i.e. propagation constant, propagation length and normalized mode area have been calculated for different values of ridge width and height at telecommunication wavelength. The respective 1D structure of the waveguide has been analytically solved for the anisotropic ridge as a single uniaxial medium with dielectric tensor defined by EMT. The 2D structure has been analyzed numerically through FEM simulation using Mode analysis module in Comsol Multiphysics. Both the EMT and real multilayer structure have been considered in numerical simulations. Such structure with all dielectric metamaterial provides an extra degree of freedom namely fill factor, fraction of Si layer in a Si-SiO2 unit cell, to tune the propagation characteristics compared to the conventional DLSSP waveguide. A wide range of variations in all the characteristics have been observed for different fill factor values. Besides, the effect of the first interface layer has also been considered. Though all dielectric metamaterial has already been utilized in photonic waveguide as cladding, the implementation in plasmonic waveguide hasn’t been investigated yet to our best knowledge. The proposed device might be a potential in deep subwavelength optics, PIC and optoelectronics.
Strain compensated superlattices on m-plane gallium nitride by ammonia molecular beam epitaxy
Authors: Fireman Micha N. , Bonef Bastien , Young Erin C. , Nookala Nishant , Belkin Mikhail A. , Speck James S.
Published: August 2017

The results of tensile strained AlN/GaN, AlGaN/GaN, and compressive strained InGaN/GaN superlattices (SLs) grown by Ammonia MBE (NH3-MBE) are presented. A combination of atom probe tomography and high-resolution X-ray diffraction confirms that periodic heterostructures of high crystallographic quality are achieved. Strain induced misfit dislocations (MDs), however, are revealed by cathodoluminescence (CL) of the strained AlN/GaN, AlGaN/GaN, and InGaN/GaN structures. MDs in the active region of a device are a severe problem as they act as non-radiative charge recombination centers, affecting the reliability and efficiency of the device. Strain compensated SL structures are subsequently developed, composed of alternating layers of tensile strained AlGaN and compressively strained InGaN. CL reveals the absence of MDs in such structures, demonstrating that strain compensation offers a viable route towards MD free active regions in III-Nitride SL based devices.
High resolution structural characterisation of laser-induced defect clusters inside diamond
Authors: Salter Patrick S. , Booth Martin J. , Courvoisier Arnaud , Moran David A. J. , MacLaren Donald A.
Published: August 2017

Laser writing with ultrashort pulses provides a potential route for the manufacture of three-dimensional wires, waveguides, and defects within diamond. We present a transmission electron microscopy study of the intrinsic structure of the laser modifications and reveal a complex distribution of defects. Electron energy loss spectroscopy indicates that the majority of the irradiated region remains as sp3 bonded diamond. Electrically conductive paths are attributed to the formation of multiple nano-scale, sp2-bonded graphitic wires and a network of strain-relieving micro-cracks.
Analysis of temperature dependent current-voltage and capacitance-voltage characteristics of an Au/V2O5/n-Si Schottky diode
Authors: Mahato Somnath , Biswas Debaleen , Gerling Luis G. , Voz Cristobal , Puigdollers Joaquim
Published: August 2017

Electronic properties of Au/V2O5/n-Si Schottky device have been investigated by temperature dependent current–voltage (I–V) and capacitance–voltage (C–V) measurements ranging from 300 K to 150 K. Ideality factor (n) and barrier height (ϕ) for the Schottky device were obtained from I–V characteristics as 2.04 and 0.83 eV at 300 K and 6.95 and 0.39 eV at 150 K respectively. It was observed that in presence of inhomogeneity at metal–semiconductor interface, the ideality factor increases and barrier height decreases with the decrease of temperature. The Richardson constant value was estimated as 137 A–cm−2–K−2 from modified Richardson plot, which is closer to the known theoretical value of n-Si where mean value of barrier height (ϕb0¯), and its standard deviation (σ0) were estimated using double Gaussian distribution (DGD) analysis. Different device parameters, namely, built-in potential, carrier concentration, image force lowering and depletion width were also obtained from the C–V–T measurements. First time use of V2O5 thin-film as an interfacial layer (IL) on Au/V2O5/n-Si Schottky diode was successfully explained by the thermionic emission (TE) theory. The interesting result obtained in this present work is the V2O5 thin-film reduced its conducting capability with decreasing temperature, while it shows a totally insulating behaviour below 150 K.
Homogeneous cooling state of dilute granular gases of charged particles
Authors: Takada Satoshi , Serero Dan , Pöschel Thorsten
Published: August 2017

We describe the velocity distribution function of a granular gas of electrically charged particles by means of a Sonine polynomial expansion and study the decay of its granular temperature. We find a dependence of the first non-trivial Sonine coefficient, a2, on time through the value of temperature. In particular, we find a sudden drop of a2 when temperature approaches a characteristic value, T*, describing the electrostatic interaction. For lower values of T, the velocity distribution function becomes Maxwellian. The theoretical calculations agree well with numerical direct simulation Monte Carlo to validate our theory.
A versatile patterning process based on easily soluble sacrificial bilayers
Authors: Harada Takayuki , Tsukazaki Atsushi
Published: August 2017

Development of a microfabrication process is essential to embed fascinating physical properties of functional materials into mesoscopic devices. Different from well-investigated materials with established microfabrication process, newly-discovered materials often meet difficulty when scaling down into a mesoscopic size, because process damages cause serious deterioration of their functionalities. Here, we demonstrate a versatile lift-off method using a carefully designed sacrificial bilayer, composed of an easily soluble layer and a thermally stable rigid layer. In this method, the target films can be grown in optimum conditions, such as high temperature and high oxygen partial pressure, on the stable pre-patterned substrate with the inorganic sacrificial bilayer. After film deposition, measurable patterned devices can be obtained just by a short-time lift-off in a mild chemical solution. We carried out micron-scale patterning and electrical measurements by applying this technique to one of perovskite oxides, SrRuO3, and Fe-based chalcogenide superconductors, FeSe, both of which are incompatible with conventional photolithography and dry-etching processes. The demonstrated narrowest line width of 5 μm is successfully patterned with maintaining the almost identical properties of the pristine films, exemplifying that process damage is minimized. The demonstrated versatile patterning process expands the range of application of emerging functional materials in thin film devices.
Frequency shift keying by current modulation in a MTJ-based STNO with high data rate
Authors: Ruiz-Calaforra A. , Purbawati A. , Brächer T. , Hem J. , Murapaka C. , Jiménez E. , Mauri D. , Zeltser A. , Katine J. A. , Cyrille M.-C. , Buda-Prejbeanu L. D. , Ebels U.
Published: August 2017

Spin torque nano-oscillators are nanoscopic microwave frequency generators which excel due to their large frequency tuning range and agility for amplitude and frequency modulation. Due to their compactness, they are regarded as suitable candidates for applications in wireless communications, where cost-effective and complementary metal-oxide semiconductor-compatible standalone devices are required. In this work, we study the ability of a magnetic-tunnel-junction based spin torque nano-oscillator to respond to a binary input sequence encoded in a square-shaped current pulse for its application as a frequency-shift-keying (FSK) based emitter. We demonstrate that below the limit imposed by the spin torque nano-oscillator intrinsic relaxation frequency, an agile variation between discrete oscillator states is possible. For this kind of devices, we demonstrate FSK up to data rates of 400 Mbps, which is well suited for the application of such oscillators in wireless networks.
Power measurements and coupler optimization in inductive discharges
Authors: Godyak V. A. , Alexandrovich B. M.
Published: August 2017

The power absorbed by the plasma is one of the key parameters which defines processes in any plasma source. This power, however, can be very different from the power at the rf power source output or the coupler terminals, which has been used in many publications to characterize the plasma. This article describes how to find the power absorbed by the plasma and the power lost in the coupler and matcher network for inductively coupled plasmas. In addition, several practical coupler configurations to reduce the coupler coil loss and minimize the rf plasma potential are discussed. We propose an effective and simple method to achieve that by the coupler coil splitting and insertion of the resonating capacitor in the middle of the coil. Our experimental data demonstrate this approach having superior coupler efficiency and substantially lower rf plasma potential.
Full-wave analysis of the high frequency characteristics of the sine waveguide slow-wave structure
Authors: Lei Xia , Wei Yanyu , Wang Yuanyuan , Zhou Qing , Wu Gangxiong , Ding Chong , Li Qian , Zhang Luqi , Jiang Xuebing , Gong Yubin , Wang Wenxiang
Published: August 2017

A theoretical model for calculation of the high frequency characteristics of the sine waveguide slow-wave structure (SWS) is proposed. The formulas of dispersion and interaction impedances of the hybrid modes are obtained by combining the Helmholtz equation with the appropriate boundary conditions. Using the full wave analysis method, it is proved that the periodic structures with a half-period shift followed leads to a pairwise closing of passbands characteristic of adjacent mode. The sine waveguide SWS for 0.22THz traveling wave tube (TWT) is chosen as an illustrative example to verify the validity of the theoretical model, and the calculation results of the dispersion curve and interaction impedance curve are consistent with the HFSS simulation results. In addition, the influences of dimensions of sine waveguide on the high frequency characteristics of +1st spatial harmonic wave are investigated by numerical calculation. The study indicates that the appropriate SWS parameters are helpful for improving the bandwidth and increasing output power of TWT.
Non-relativistic limits of rarefaction wave to the 1-D piston problem for the isentropic relativistic Euler equations
Authors: Ding Min , Li Yachun
Published: August 2017

We consider the 1-D piston problem for the isentropic relativistic Euler equations when the total variations of the initial data and the speed of the piston are both sufficiently small. By a modified wave front tracking method, we establish the global existence of entropy solutions including a strong rarefaction wave without restriction on the strength. Meanwhile, we study the convergence of the entropy solutions to the corresponding entropy solutions of the classical non-relativistic isentropic Euler equations as the light speed c→+∞.
Electrostatic and induction effects in the solubility of water in alkanes
Authors: Asthagiri D. , Valiya Parambathu Arjun , Ballal Deepti , Chapman Walter G.
Published: August 2017

Experiments show that at 298 K and 1 atm pressure, the transfer free energy, μex, of water from its vapor to liquid normal alkanes CnH2n+2 (n=5…12) is negative. Earlier it was found that with the united-atom TraPPE model for alkanes and the SPC/E model for water, one had to artificially enhance the attractive alkane-water cross interaction to capture this behavior. Here we revisit the calculation of μex using the polarizable AMOEBA and the non-polarizable Charmm General (CGenFF) forcefields. We test both the AMOEBA03 and AMOEBA14 water models; the former has been validated with the AMOEBA alkane model while the latter is a revision of AMOEBA03 to better describe liquid water. We calculate μex using the test particle method. With CGenFF, μex is positive and the error relative to experiments is about 1.5 kBT. With AMOEBA, μex is negative and deviations relative to experiments are between 0.25 kBT (AMOEBA14) and 0.5 kBT (AMOEBA03). Quantum chemical calculations in a continuum solvent suggest that zero point effects may account for some of the deviation. Forcefield limitations notwithstanding, electrostatic and induction effects, commonly ignored in consideration of water-alkane interactions, appear to be decisive in the solubility of water in alkanes.
Controlling resonance energy transfer in nanostructure emitters by positioning near a mirror
Authors: Weeraddana Dilusha , Premaratne Malin , Gunapala Sarath D. , Andrews David L.
Published: August 2017

The ability to control light-matter interactions in quantum objects opens up many avenues for new applications. We look at this issue within a fully quantized framework using a fundamental theory to describe mirror-assisted resonance energy transfer (RET) in nanostructures. The process of RET communicates electronic excitation between suitably disposed donor and acceptor particles in close proximity, activated by the initial excitation of the donor. Here, we demonstrate that the energy transfer rate can be significantly controlled by careful positioning of the RET emitters near a mirror. The results deliver equations that elicit new insights into the associated modification of virtual photon behavior, based on the quantum nature of light. In particular, our results indicate that energy transfer efficiency in nanostructures can be explicitly expedited or suppressed by a suitably positioned neighboring mirror, depending on the relative spacing and the dimensionality of the nanostructure. Interestingly, the resonance energy transfer between emitters is observed to “switch off” abruptly under suitable conditions of the RET system. This allows one to quantitatively control RET systems in a new way.
Heating- and pressure-induced transformations in amorphous and hexagonal ice: A computer simulation study using the TIP4P/2005 model
Authors: Engstler Justin , Giovambattista Nicolas
Published: August 2017

We characterize the phase behavior of glassy water by performing extensive out-of-equilibrium molecular dynamics simulations using the TIP4P/2005 water model. Specifically, we study (i) the pressure-induced transformations between low-density (LDA) and high-density amorphous ice (HDA), (ii) the pressure-induced amorphization (PIA) of hexagonal ice (Ih), (iii) the heating-induced LDA-to-HDA transformation at high pressures, (iv) the heating-induced HDA-to-LDA transformation at low and negative pressures, (v) the glass transition temperatures of LDA and HDA as a function of pressure, and (vi) the limit of stability of LDA upon isobaric heating and isothermal decompression (at negative pressures). These transformations are studied systematically, over a wide range of temperatures and pressures, allowing us to construct a P-T phase diagram for glassy TIP4P/2005 water. Our results are in qualitative agreement with experimental observations and with the P-T phase diagram obtained for glassy ST2 water that exhibits a liquid-liquid phase transition and critical point. We also discuss the mechanism for PIA of ice Ih and show that this is a two-step process where first, the hydrogen-bond network (HBN) is distorted and then the HBN abruptly collapses. Remarkably, the collapse of the HB in ice Ih occurs when the average molecular orientations order, a measure of the tetrahedrality of the HBN, is of the same order as in LDA, suggesting a common mechanism for the LDA-to-HDA and Ih-to-HDA transformations.
A hyperspectral X-ray computed tomography system for enhanced material identification
Authors: Wu Xiaomei , Wang Qian , Ma Jinlei , Zhang Wei , Li Po , Fang Zheng
Published: August 2017

X-ray computed tomography (CT) can distinguish different materials according to their absorption characteristics. The hyperspectral X-ray CT (HXCT) system proposed in the present work reconstructs each voxel according to its X-ray absorption spectral characteristics. In contrast to a dual-energy or multi-energy CT system, HXCT employs cadmium telluride (CdTe) as the x-ray detector, which provides higher spectral resolution and separate spectral lines according to the material’s photon-counter working principle. In this paper, a specimen containing ten different polymer materials randomly arranged was adopted for material identification by HXCT. The filtered back-projection algorithm was applied for image and spectral reconstruction. The first step was to sort the individual material components of the specimen according to their cross-sectional image intensity. The second step was to classify materials with similar intensities according to their reconstructed spectral characteristics. The results demonstrated the feasibility of the proposed material identification process and indicated that the proposed HXCT system has good prospects for a wide range of biomedical and industrial nondestructive testing applications.
Efficiently sampling conformations and pathways using the concurrent adaptive sampling (CAS) algorithm
Authors: Ahn Surl-Hee , Grate Jay W. , Darve Eric F.
Published: August 2017

Molecular dynamics simulations are useful in obtaining thermodynamic and kinetic properties of bio-molecules, but they are limited by the time scale barrier. That is, we may not obtain properties’ efficiently because we need to run microseconds or longer simulations using femtosecond time steps. To overcome this time scale barrier, we can use the weighted ensemble (WE) method, a powerful enhanced sampling method that efficiently samples thermodynamic and kinetic properties. However, the WE method requires an appropriate partitioning of phase space into discrete macrostates, which can be problematic when we have a high-dimensional collective space or when little is known a priori about the molecular system. Hence, we developed a new WE-based method, called the “Concurrent Adaptive Sampling (CAS) algorithm,” to tackle these issues. The CAS algorithm is not constrained to use only one or two collective variables, unlike most reaction coordinate-dependent methods. Instead, it can use a large number of collective variables and adaptive macrostates to enhance the sampling in the high-dimensional space. This is especially useful for systems in which we do not know what the right reaction coordinates are, in which case we can use many collective variables to sample conformations and pathways. In addition, a clustering technique based on the committor function is used to accelerate sampling the slowest process in the molecular system. In this paper, we introduce the new method and show results from two-dimensional models and bio-molecules, specifically penta-alanine and a triazine trimer.
Measurement of turbulent spatial structure and kinetic energy spectrum by exact temporal-to-spatial mapping
Authors: Buchhave Preben , Velte Clara M.
Published: August 2017

We present a method for converting a time record of turbulent velocity measured at a point in a flow to a spatial velocity record consisting of consecutive convection elements. The spatial record allows computation of dynamic statistical moments such as turbulent kinetic wavenumber spectra and spatial structure functions in a way that completely bypasses the need for Taylor’s hypothesis. The spatial statistics agree with the classical counterparts, such as the total kinetic energy spectrum, at least for spatial extents up to the Taylor microscale. The requirements for applying the method are access to the instantaneous velocity magnitude, in addition to the desired flow quantity, and a high temporal resolution in comparison to the relevant time scales of the flow. We map, without distortion and bias, notoriously difficult developing turbulent high intensity flows using three main aspects that distinguish these measurements from previous work in the field: (1) The measurements are conducted using laser Doppler anemometry and are therefore not contaminated by directional ambiguity (in contrast to, e.g., frequently employed hot-wire anemometers); (2) the measurement data are extracted using a correctly and transparently functioning processor and are analysed using methods derived from first principles to provide unbiased estimates of the velocity statistics; (3) the exact mapping proposed herein has been applied to the high turbulence intensity flows investigated to avoid the significant distortions caused by Taylor’s hypothesis. The method is first confirmed to produce the correct statistics using computer simulations and later applied to measurements in some of the most difficult regions of a round turbulent jet—the non-equilibrium developing region and the outermost parts of the developed jet. The proposed mapping is successfully validated using corresponding directly measured spatial statistics in the fully developed jet, even in the difficult outer regions of the jet where the average convection velocity is negligible and turbulence intensities increase dramatically. The measurements in the developing region reveal interesting features of an incomplete Richardson-Kolmogorov cascade under development.
The build-up of energetic electrons triggering electron cyclotron emission bursts due to a magnetohydrodynamic mode at the edge of tokamaks
Authors: Li Erzhong , Austin M. E. , White R. B. , Taylor G.
Published: August 2017

Intense bursts of electron cyclotron emission (ECE) triggered by magnetohydrodynamic (MHD) instabilities such as edge localized modes have been observed on many tokamaks. On the DIII-D tokamak, it is found that a MHD mode is necessary in order to trigger the ECE bursts in the low collisionality regime at the plasma edge. ORBIT-code simulations have shown that energetic electrons build up due to an interaction between barely trapped electrons with a MHD mode (f = 50 kHz for the current case). The energetic tail of the electron distribution function develops a bump within several microseconds for this collisionless case. This behavior depends on the competition between the perturbing MHD mode and slowing down and pitch angle scattering due to collisions. For typical DIII-D parameters, the calculated ECE radiation transport predicted by ORBIT is in excellent agreement with ECE measurements, clarifying the electron dynamics of the ECE bursts for the first time.
Laser-driven hydrothermal process studied with excimer laser pulses
Authors: Mariella Raymond , Rubenchik Alexander , Fong Erika , Norton Mary , Hollingsworth William , Clarkson James , Johnsen Howard , Osborn David L.
Published: August 2017

Previously, we discovered [Mariella et al., J. Appl. Phys. 114, 014904 (2013)] that modest-fluence/modest-intensity 351-nm laser pulses, with insufficient fluence/intensity to ablate rock, mineral, or concrete samples via surface vaporization, still removed the surface material from water-submerged target samples with confinement of the removed material, and then dispersed at least some of the removed material into the water as a long-lived suspension of nanoparticles. We called this new process, which appears to include the generation of larger colorless particles, “laser-driven hydrothermal processing” (LDHP) [Mariella et al., J. Appl. Phys. 114, 014904 (2013)]. We, now, report that we have studied this process using 248-nm and 193-nm laser light on submerged concrete, quartzite, and obsidian, and, even though light at these wavelengths is more strongly absorbed than at 351 nm, we found that the overall efficiency of LDHP, in terms of the mass of the target removed per Joule of laser-pulse energy, is lower with 248-nm and 193-nm laser pulses than with 351-nm laser pulses. Given that stronger absorption creates higher peak surface temperatures for comparable laser fluence and intensity, it was surprising to observe reduced efficiencies for material removal. We also measured the nascent particle-size distributions that LDHP creates in the submerging water and found that they do not display the long tail towards larger particle sizes that we had observed when there had been a multi-week delay between experiments and the date of measuring the size distributions. This is consistent with transient dissolution of the solid surface, followed by diffusion-limited kinetics of nucleation and growth of particles from the resulting thin layer of supersaturated solution at the sample surface.
Memory in a fractional-order cardiomyocyte model alters properties of alternans and spontaneous activity
Authors: Comlekoglu T. , Weinberg S. H.
Published: August 2017

Cardiac memory is the dependence of electrical activity on the prior history of one or more system state variables, including transmembrane potential (Vm), ionic current gating, and ion concentrations. While prior work has represented memory either phenomenologically or with biophysical detail, in this study, we consider an intermediate approach of a minimal three-variable cardiomyocyte model, modified with fractional-order dynamics, i.e., a differential equation of order between 0 and 1, to account for history-dependence. Memory is represented via both capacitive memory, due to fractional-order Vm dynamics, that arises due to non-ideal behavior of membrane capacitance; and ionic current gating memory, due to fractional-order gating variable dynamics, that arises due to gating history-dependence. We perform simulations for varying Vm and gating variable fractional-orders and pacing cycle length and measure action potential duration (APD) and incidence of alternans, loss of capture, and spontaneous activity. In the absence of ionic current gating memory, we find that capacitive memory, i.e., decreased Vm fractional-order, typically shortens APD, suppresses alternans, and decreases the minimum cycle length (MCL) for loss of capture. However, in the presence of ionic current gating memory, capacitive memory can prolong APD, promote alternans, and increase MCL. Further, we find that reduced Vm fractional order (typically less than 0.75) can drive phase 4 depolarizations that promote spontaneous activity. Collectively, our results demonstrate that memory reproduced by a fractional-order model can play a role in alternans formation and pacemaking, and in general, can greatly increase the range of electrophysiological characteristics exhibited by a minimal model.
Assessing multiscale complexity of short heart rate variability series through a model-based linear approach
Authors: Porta Alberto , Bari Vlasta , Ranuzzi Giovanni , De Maria Beatrice , Baselli Giuseppe
Published: August 2017

We propose a multiscale complexity (MSC) method assessing irregularity in assigned frequency bands and being appropriate for analyzing the short time series. It is grounded on the identification of the coefficients of an autoregressive model, on the computation of the mean position of the poles generating the components of the power spectral density in an assigned frequency band, and on the assessment of its distance from the unit circle in the complex plane. The MSC method was tested on simulations and applied to the short heart period (HP) variability series recorded during graded head-up tilt in 17 subjects (age from 21 to 54 years, median = 28 years, 7 females) and during paced breathing protocols in 19 subjects (age from 27 to 35 years, median = 31 years, 11 females) to assess the contribution of time scales typical of the cardiac autonomic control, namely in low frequency (LF, from 0.04 to 0.15 Hz) and high frequency (HF, from 0.15 to 0.5 Hz) bands to the complexity of the cardiac regulation. The proposed MSC technique was compared to a traditional model-free multiscale method grounded on information theory, i.e., multiscale entropy (MSE). The approach suggests that the reduction of HP variability complexity observed during graded head-up tilt is due to a regularization of the HP fluctuations in LF band via a possible intervention of sympathetic control and the decrement of HP variability complexity observed during slow breathing is the result of the regularization of the HP variations in both LF and HF bands, thus implying the action of physiological mechanisms working at time scales even different from that of respiration. MSE did not distinguish experimental conditions at time scales larger than 1. Over a short time series MSC allows a more insightful association between cardiac control complexity and physiological mechanisms modulating cardiac rhythm compared to a more traditional tool such as MSE.