bluuebunny/crossref_metadata_2025 huggingface dataset:
Photodissociation of aniline N–H bonds in clusters of different nature
Authors: Poterya Viktoriya , Nachtigallová Dana , Lengyel Jozef , Fárník Michal
Published: September 2015

The solvent effects on the photodissociation of aniline in cluster environments have been investigated by H-photofragment velocity map imaging at 243 nm, mass spectrometry after electron ionization, and ab initio calculations.
Absolute configuration and chiral self-assembly of rubrene on Bi(111)
Authors: Sun Kai , Lan Meng , Wang Jun-Zhong
Published: September 2015

We investigated the chiral self-assembly of rubrene molecules on a semi-metallic Bi(111) surface using low-temperature scanning tunneling microscopy.
Correction: The transformation from amorphous iron phosphate to sodium iron phosphate in sodium-ion batteries
Authors: Liu Yao , Zhou Yirong , Zhang Junxi , Zhang Shiming , Xu Shuojiong
Published: September 2015

Correction for ‘The transformation from amorphous iron phosphate to sodium iron phosphate in sodium-ion batteries’ by Yao Liu et al., Phys. Chem. Chem. Phys., 2015, 17, 22144–22151.
Self-assembly of a fac-Mn(CO)3-core containing dinuclear metallacycles using flexible ditopic linkers
Authors: Karthikeyan S. , Nagarajaprakash R. , Satheesh Garisekurthi , Ashok Kumar Chowan , Manimaran Bala.
Published: September 2015

Flexible dimanganese metallacycles have been achieved using Mn(CO)5Br and adaptable ditopic pyridyl linkers. The host–guest chemistry of Mn(i)-dinuclear metallacycles has been explored.
A dual functional probe for “turn-on” fluorescence response of Pb2+and colorimetric detection of Cu2+based on a rhodamine derivative in aqueous media
Authors: Li Min , Jiang Xiu-Juan , Wu Hui-Hui , Lu Hong-Lin , Li Hai-Yang , Xu Hong , Zang Shuang-Quan , Mak Thomas C. W.
Published: September 2015

A dual functional probeLexhibited a selective fluorescence enhancement response to Pb2+and a sensitive colorimetric response to Cu2+in aqueous media.
A pilot-scale study of a powdered activated carbon-membrane bioreactor for the treatment of water with a high concentration of ammonia
Authors: Shao Senlin , Qu Fangshu , Liang Heng , Chang Haiqing , Yu Huarong , Li Guibai
Published: September 2015

Ammonia removal was highly impacted by temperature and alkalinity. Fouling cake could remove a certain amount of ammonia.
Polyethylene glycol-bonded 1,8-diazabicyclo[5.4.0]undec-7-ene (PEG–DBU) as a surfactant-combined base catalyst for the application of nucleosides as reagents in multi-component syntheses of 8-substituted pyrido[2,3-d]pyrimidine-6-carbonitriles in water
Authors: Shekouhy Mohsen , Khalafi-Nezhad Ali
Published: September 2015

PEG–DBU: a surfactant-combined base catalyst for the synthesis of 8-substituted pyrido[2,3-d]pyrimidine-6-carbonitriles in water.
Synthesis, characterization and reactivity of a six-membered cyclic glycerol carbonate bearing a free hydroxyl group
Authors: Tryznowski M. , Żołek-Tryznowska Z. , Świderska A. , Parzuchowski P. G.
Published: September 2015

For the first time, synthesis of the simplest derivative of glycerol, a six-membered cyclic glycerol carbonate (5-hydroxy-1,3-dioxan-2-one), from glycerol is presented.
Stereoselective organocatalysed reactions in deep eutectic solvents: highly tunable and biorenewable reaction media for sustainable organic synthesis
Authors: Massolo Elisabetta , Palmieri Silvia , Benaglia Maurizio , Capriati Vito , Perna Filippo M.
Published: September 2015

Different metal-free catalytic enantioselective reactions have been performed in high yields and enantioselectivity in natural, biorenewable and environmentally-friendly DESs. The recyclability of the chiral catalyst by a simple extraction protocol was also successfully accomplished.
Electrochemical synthesis of organochalcogenides in aqueous medium
Authors: Ribeiro Neto Pedro B. , Santana Sonydelane O. , Levitre Guillaume , Galdino Danilo , Oliveira Jadson L. , Ribeiro Rogério T. , Barros Maria E. S. B. , Bieber Lothar W. , Menezes Paulo H. , Navarro Marcelo
Published: September 2015

The electrochemical preparation of telluride, selenide and sulfide ions was carried out in NaOH aqueous solution, using a two compartment cell.
Modeling and CFD simulation of nutrient distribution in picoliter bioreactors for bacterial growth studies on single-cell level
Authors: Westerwalbesloh Christoph , Grünberger Alexander , Stute Birgit , Weber Sophie , Wiechert Wolfgang , Kohlheyer Dietrich , von Lieres Eric
Published: September 2015

A microfluidic device for microbial single-cell cultivation of bacteria was modeled and simulated to identify potential substrate limitations or product accumulations.
DMT1 iron uptake in the PNS: bridging the gap between injury and regeneration
Authors: Martinez-Vivot Rocío , Copello Guillermo , Leal Celeste , Piñero Gonzalo , Usach Vanina , Rozenszajn Mijael , Morelli Laura , Setton-Avruj Clara Patricia
Published: September 2015

This work supports DMT1 involvement in iron regulation in SCs, its role as a sensor of iron necessity and its ability to guarantee iron supply during myelination and remyelination.
The S2 Cu(i) site in CupA from Streptococcus pneumoniae is required for cellular copper resistance
Authors: Fu Yue , Bruce Kevin E. , Wu Hongwei , Giedroc David P.
Published: September 2015

We report the solution structure of apo-CupA and establish the functional primacy of the S2 Cu(i) in cellular copper resistance.
Chemical bibliographic databases: the influence of term indexing policies on topic searches
Authors: Niel Gilles , Boyrie Fabrice , Virieux David
Published: September 2015

How many articles can we retrieve from a topic search in chemical bibliographic databases?
Synthesis and biological evaluation of pyrazolo–triazole hybrids as cytotoxic and apoptosis inducing agents
Authors: Srinivasa Reddy T. , Kulhari Hitesh , Ganga Reddy V. , Subba Rao A. V. , Bansal Vipul , Kamal Ahmed , Shukla Ravi
Published: September 2015

A series of pyrazolo–triazole hybrids were designed and synthesized by combining the 1,3-diphenyl pyrazole and triazole scaffolds to obtain (1-benzyl-1H-1,2,3-triazol-4-yl)(1,3-diphenyl-1H-pyrazol-4-yl)methanones.
A versatile approach towards multivalent saccharide displays on magnetic nanoparticles and phospholipid vesicles
Authors: Coxon Thomas P. , Fallows Thomas W. , Gough Julie E. , Webb Simon J.
Published: September 2015

A simple synthetic route to lipid, resorcinol and catechol adducts of saccharides has been developed, and used to give multivalent displays on the surface of nanostructures for cell targeting.
Synthesis and application of a dual chiral [2.2]paracyclophane-based N-heterocyclic carbene in enantioselective β-boration of acyclic enones
Authors: Wang Lei , Chen Zhen , Ma Manyuan , Duan Wenzeng , Song Chun , Ma Yudao
Published: September 2015

A N-heterocyclic carbene was used as both an organocatalyst and a ligand for transition metal catalysis in asymmetric boration.
A theoretical prediction on CN6O: structure, stability and performance
Authors: Yu Tao , Wu Bo
Published: September 2015

The explored CN6O isomers are more efficient than carbonyl diazide as rocket fuel.
Silver-catalyzed [3 + 2] cycloaddition of isocyanides with diazo compounds: new regioselective access to 1,4-disubstituted-1,2,3-triazoles
Authors: Wang Shuai , Yang Li-Jun , Zeng Jun-Liang , Zheng Yan , Ma Jun-An
Published: September 2015

An unprecedented silver-catalyzed 1,3-dipolar cycloaddition reaction of isocyanides with diazo compounds to afford 1,4-disubstituted 1,2,3-triazoles is realized.
Surface-initiated polymerization of A–A/B–B type conjugated monomers by palladium-catalyzed Stille polycondensation: towards low band gap polymer brushes
Authors: Awada Hussein , Bousquet Antoine , Dagron-Lartigau Christine , Billon Laurent
Published: September 2015

A surface-initiated Stille polycondensation from Pd catalyst-immobilized ZnO nanorods affords well-defined core–shell nanoparticles. For the first time, a low band gap polymer was anchored on ZnO nanorods to create hybrid materials with tunable photophysical properties.
Flexible PEGDA-based microneedle patches with detachable PVP–CD arrowheads for transdermal drug delivery
Authors: Xue Peng , Zhang Xuyang , Chuah Yon Jin , Wu Yafeng , Kang Yuejun
Published: September 2015

A polymer-based microneedle patch with drug-loaded and detachable arrowhead tips for transdermal drug delivery.
Direct-writing of circuit interconnects on cellulose paper using ultra-long, silver nanowires based conducting ink
Authors: Nair Keerthi G. , Jayaseelan D. , Biji P.
Published: September 2015

A highly stable conducting nanoink based on silver ultra-long nanowires (Ag ULNWs) was developed by a self-seeding polyol method with controlled doping of silver acetate for flexible electronics applications.
Investigations into a thiol-impregnated CaCO3-based adsorbent for mercury removal: a full factorial design approach
Authors: Balasundaram Karthik , Sharma Mukesh
Published: September 2015

We demonstrated removal of Hg0 vapor by adsorbing it on thiol-impregnated calcium carbonate and assessed the significance of temperature and thiol mass in Hg0 removal.
Fabrication of barium titanate/acrylonitrile-butadiene styrene/poly(methyl methacrylate) nanocomposite films for hybrid ferroelectric capacitors
Authors: Parizi Saman Salemizadeh , Conley Gavin , Costanzo Tommaso , Howell Bob , Mellinger Axel , Caruntu Gabriel
Published: September 2015

A new organic–inorganic ferroelectric hybrid capacitor designed by uniformly incorporating monodisperse 15 nm ferroelectric BaTiO3 nanocubes into non-polar polymer blends of poly(methyl methacrylate) (PMMA) and acrylonitrile-butadiene-styrene (ABS) terpolymer is described.
A simple lateral flow biosensor for the rapid detection of copper(ii) ions based on click chemistry
Authors: Wang Dou , Ge Chenchen , Wang Lin , Xing Xuerong , Zeng Lingwen
Published: September 2015

A simple and enzyme-free lateral flow biosensor for the rapid detection of Cu2+ based on copper(i) ion (Cu+)-catalyzed click chemistry has been constructed for the first time.
Vapour pressure and mixing thermodynamic properties of the KNbO3–NaNbO3system
Authors: Popovič A. , Bencze L. , Koruza J. , Malič B.
Published: September 2015

The analytical description of excess functions was made possible using more advanced treatment of experimental data with respect to literature.
Functionalized multi-walled carbon nanotubes as an efficient reusable heterogeneous catalyst for green synthesis of N-substituted pyrroles in water
Authors: Naeimi Hossein , Dadaei Mahla
Published: September 2015

In this protocol, the functionalization of multi-walled carbon nanotubes (MWCNTs) was investigated and they were applied as a recyclable heterogeneous catalyst for the synthesis of N-substituted pyrroles.
A urine metabonomics study of chronic renal failure and intervention effects of total aglycone extracts of Scutellaria baicalensis in 5/6 nephrectomy rats
Authors: Fang Junwei , Wang Wenyu , Sun Shujun , Wang Yang , Li Qianhua , Lu Xiong , Hao Zhihui , Zhang Yongyu
Published: September 2015

This study was to clarify the pathogenesis of CRF and action mechanism of TAES.
Effect of functionalized multi-walled carbon nanotubes on the microstructure and performances of PVDF membranes
Authors: Yu Zongxue , Zeng Guangyong , Pan Yang , Lv Liang , Min Hui , Zhang Lei , He Yi
Published: September 2015

Functionalized multi-walled carbon nanotubes (f-MWCNTs) were synthesized by grafting carboxyl groups and 3-aminopropyltriethoxysilane (APTS) on the nanotube surface, respectively.
Synergistic effect of sandwich polyoxometalates and copper–imidazole complexes for enhancing the peroxidase-like activity
Authors: Chai Dong-Feng , Ma Zhuo , Yan Hong , Qiu YunFeng , Liu Hong , Guo Hua-Dong , Gao Guang-Gang
Published: September 2015

Two inorganic–organic hybrids based on copper(ii)–imidazole complex modified sandwich-type tungstobismuthate or tungstoantimonite, have been synthesized, demonstrating higher peroxidase-like activity using TMB as a peroxidase substrate.
Improved understanding of particle migration modes in spiral inertial microfluidic devices
Authors: Xiang Nan , Shi Zhiguo , Tang Wenlai , Huang Di , Zhang Xinjie , Ni Zhonghua
Published: September 2015

The migration dynamics of particles with sizes ranging from micro- to nano-scales in spiral inertial microfluidic devices was investigated, and three different migration modes was discovered.
Cs2CO3-promoted [3 + 2] cycloaddition providing an easy protocol toward imidazo[1,2-a]indole derivatives
Authors: Zhang Li-Dan , Qiu Jiang-Kai , Kong Li-Fang , Hao Wen-Juan , Miao Jiao-Na , Wu Shuo , Jiang Bo , Tu Shu-Jiang
Published: September 2015

A base-promoted [3 + 2] cycloaddition for the construction of multi-functionalized imidazo[1,2-a]indole derivatives with good yields has been accomplished.
Enhanced corneal permeation of coumarin-6 using nanoliposomes containing dipotassium glycyrrhizinate: in vitro mechanism and in vivo permeation evaluation
Authors: Guo Chuanlong , Cui Fenghua , Li Mengshuang , Li Fengjie , Wu Xianggen
Published: September 2015

The fluidity of the liposomal membrane differently affected cellular uptake/internalization and in vivo corneal penetration of the nanoliposomes.
The enhanced photocatalytic properties of BiOCl/BiVO4 p–n heterojunctions via plasmon resonance of metal Bi
Authors: Feng Chenchen , Wang Dahui , Jin Bingjun , Jiao Zhengbo
Published: September 2015

Novel p–n heterojunctions of BiOCl/BiVO4 nanosheets have been first fabricated via a one step method and the photocatalytic and photoelectrochemical activities can be further improved by depositing metallic Bi owing to its plasmon resonance and the improved charge separation.
Self-templating noncatalyzed synthesis of monolithic boron nitride nanowires
Authors: Su Chao-Hua , Wang Ru-Zhi , Zhang Yue-Fei , Zhang Xing-Wang , Yan Hui
Published: September 2015

Achieving economic orientation-controlled growth of monolithic nanowires remains a challenge.
A novel electronic nose for simultaneous quantitative determination of concentrations and odor intensity analysis of benzene, toluene and ethylbenzene mixtures
Authors: Jiang Shen , Liu Jiemin , Fang Di , Yan Luchun , Wu Chuandong
Published: September 2015

Development of a novel E-nose system to simultaneously determine chemical concentrations and odor intensity of benzene, toluene and ethylbenzene mixtures.
Enhancing the effect of bisulfite on sequestration of selenite by zerovalent iron
Authors: Li Jinxiang , Wang Chao , Qiao Junlian , Qin Hejie , Li Lina
Published: September 2015

The enhancing effect of HSO3− on Se(iv) sequestration varied with the headspace volume, HSO3− concentration and initial pH, respectively.
Predictive calculation of carbon dioxide solubility in polymers
Authors: Ru-Ting Xia , Xing-Yuan Huang
Published: September 2015

Novel calculation model of CO2solubility in polymers using a hybrid intelligence algorithm.
Solvothermal synthesis of GO/V2O5 composites as a cathode material for rechargeable magnesium batteries
Authors: Du Xinchuan , Huang Gang , Qin Yuling , Wang Limin
Published: September 2015

GO/V2O5 composites prepared from a solvothermal reaction exhibited greatly enhanced electrochemical performances as a cathode material for rechargeable magnesium batteries.
Photoactive composite films prepared from mixtures of polystyrene microgel dispersions and poly(3-hexylthiophene) solutions
Authors: Chen Mu , Cui Zhengxing , Edmondson Steve , Hodson Nigel , Zhou Mi , Yan Junfeng , O'Brien Paul , Saunders Brian R.
Published: September 2015

Composite polystyrene microgel/P3HT films have been prepared that contain islands of 2D-microgel crystals, are electrically conducting and show tuneable light absorption.
A theory for the phase behavior of mixtures of active particles
Authors: Takatori Sho C. , Brady John F.
Published: September 2015

A simple mechanical theory explains the “temperature” of active matter and predicts the phase behavior of a mixture of active Brownian particles with different activities.
Synthesis and evaluation of porous azo-linked polymers for carbon dioxide capture and separation
Authors: Arab Pezhman , Parrish Emily , İslamoğlu Timur , El-Kaderi Hani M.
Published: September 2015

The correlation between the CO2-capturing ability of porous azo-linked polymers and their structural properties was investigated.
Folic acid-tethered poly(N-isopropylacrylamide)–phospholipid hybrid nanocarriers for targeted drug delivery
Authors: John Johnson V. , Jeong Young-Il , Johnson Renjith P. , Chung Chung-Wook , Park Huiju , Kang Dae Hwan , Cho Jin Ku , Kim Yongjin , Kim Il
Published: September 2015

Folic acid-tethered poly(N-isopropylacrylamide)–phospholipid nanocarriers exhibit tumour targetability and temperature responsive Doxorubicin releasing behaviour under physiological conditions.
Hollow hydroxyapatite/polyelectrolyte hybrid microparticles with controllable size, wall thickness and drug delivery properties
Authors: Wei Jing , Shi Jun , Wu Qiong , Yang Liu , Cao Shaokui
Published: September 2015

Hollow hydroxyapatite/polyelectrolyte microparticles with controllable size, wall thickness and drug delivery properties have been fabricated via the green hydrothermal method and the LbL self-assembly technique.
Exact method for the stability analysis of time delayed linear‐time invariant fractional‐order systems
Authors: Pakzad Mohammad Ali , Pakzad Sara , Nekoui Mohammad Ali
Published: September 2015

In this study, a practical analytical procedure is introduced for determining the stability robustness map of a general class of linear‐time invariant fractional‐order systems with single and multiple commensurate delays of retarded type, against delay uncertainties. The complexity arises due to the exponential type transcendental terms and fractional order in their characteristic equation (CE). It is shown that this procedure analytically reveals all possible stability regions exclusively in the parametric space of the time delay. Using the presented method in this study, first, the authors will eliminate the transcendental terms of exponential type from the CE and then, they can determine all the locations where roots pass through the imaginary axis. By definition of root tendency on the boundary of each interval, the number of unstable roots in each region is calculated. Finally, the concept of stability is expressed in the intervals of delay values. The effectiveness of the proposed method results is illustrated via six numerical examples and to gain a better understanding of the problem, the root‐locus curve of these systems has been depicted as a function of delay parameter changes.
Deterministic generation of symmetric multi‐qubit Dicke states: an application of quantum feedback control
Authors: Wei Jia‐Hua , Qi Bo , Dai Hong‐Yi , Huang Jian‐Hua , Zhang Ming
Published: September 2015

In this study, the authors explore how to deterministically generate symmetric multi‐qubit Dicke states such as symmetric W‐states, from arbitrary initial states in a cavity quantum electrodynamics (QED) system with the aid of measurement‐based quantum feedback control. The concrete implementation procedures of the feedback strategy, which is constructed in the form of only two constant modes, are presented in detail. In addition, the feasibility of the control scheme in preparing symmetric multi‐qubit Dicke states is explicitly demonstrated by theoretical studies and numerical simulations.
Orientational anisotropy in simulated vapor-deposited molecular glasses
Authors: Lyubimov Ivan , Antony Lucas , Walters Diane M. , Rodney David , Ediger M. D. , de Pablo Juan J.
Published: September 2015

Enhanced kinetic stability of vapor-deposited glasses has been established for a variety of glass organic formers. Several recent reports indicate that vapor-deposited glasses can be orientationally anisotropic. In this work, we present results of extensive molecular simulations that mimic a number of features of the experimental vapor deposition process. The simulations are performed on a generic coarse-grained model and an all-atom representation of N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine (TPD), a small organic molecule whose vapor-deposited glasses exhibit considerable orientational anisotropy. The coarse-grained model adopted here is found to reproduce several key aspects reported in experiments. In particular, the molecular orientation of vapor-deposited glasses is observed to depend on substrate temperature during deposition. For a fixed deposition rate, the molecular orientation in the glasses changes from isotropic, at the glass transition temperature, Tg, to slightly normal to the substrate at temperatures just below Tg. Well below Tg, molecular orientation becomes predominantly parallel to the substrate. The all-atom model is used to confirm some of the equilibrium structural features of TPD interfaces that arise above the glass transition temperature. We discuss a mechanism based on distinct orientations observed at equilibrium near the surface of the film, which get trapped within the film during the non-equilibrium process of vapor deposition.
A blowup criterion for viscous, compressible, and heat-conductive magnetohydrodynamic flows
Authors: Du Lili , Wang Yongfu
Published: September 2015

In this paper, we proved a blowup criterion for the two-dimensional (2D) viscous, compressible, and heat-conducting magnetohydrodynamic (MHD) flows for Cauchy problem, which depends only on the divergence of the velocity vector field, as well as for the case of bounded domain with Dirichlet boundary conditions. This result indicates that the nature of the blowup for compressible models of viscous media in 2D space is similar to the barotropic compressible Navier-Stokes equations and does not depend on further sophistication of the MHD model. More precisely, taking into account the magnetic effects and heat conductivity does not introduce any new features in the blowup mechanism of full MHD flows, especially, which is independent of the temperature and the magnetic field. The results also imply the global regularity of the strong solution to compressible MHD flows, provided that velocity divergence remains bounded.
Current states in superconducting films: Numerical results
Authors: Bezuglyi E. V.
Published: September 2015

We present numerical solutions of Aslamazov–Lempitskiy (AL) equations for distributions of the transport current density in thin superconducting films in the absence of external magnetic field, in both the Meissner and the vortex states. These solutions describe smooth transition between the regimes of a wide film and a narrow channel and enable us to find critical currents and current-voltage characteristics within a wide range of the film width and temperature. The normalized critical currents and the electric field were found to be universal functions of the relation between the film width and the magnetic field penetration depth. We calculate the fitting constants of the AL theory and propose approximating formulas for the current density distributions and critical currents.
Diagnostics of composition and size of clusters formed in supersonic jets of Ar–Kr gas mixtures
Authors: Danylchenko O. G. , Kovalenko S. I. , Konotop O. P. , Samovarov V. N.
Published: September 2015

The electron diffraction technique is employed to study the component composition of binary Ar–Kr clusters with N¯=1×103−9×104 atoms/cluster as a function of cluster size and the composition of the feed gas mixture. A diagram showing the conditions under which homogeneous Kr clusters rather than heterogeneous Ar–Kr clusters are generated in the jet is presented for the first time. It is found that the key parameters to analyze the composition of clusters are the critical cluster radius Rcr and the critical Kr gas concentration Ccr. For the parameter range of heterogeneous cluster formation (CKrgas < Ccr and R > Rcr), an analytical expression is provided which describes quantitatively the enrichment of such clusters with krypton. The results obtained allow one to predict the composition of clusters produced in experiments with binary jets of noble and simple molecular gases, as well as to control simultaneously their size and composition.
A study of the magnetic properties of a quasi-one-dimensional magnet β-TeVO4 in the frame of the J1–J2 model
Authors: Savina Yu. O. , Bludov A. N. , Pashchenko V. A. , Gnatchenko S. L. , Savin Yu. V. , Schäfer S. , Lemmens P. , Berger H.
Published: September 2015

Magnetic properties of single crystal β-TeVO4 with a zigzag chain of magnetic centers (V4+ ions, S = 1/2) are analyzed in the framework of the J1–J2 model. The best agreement with experimental data is obtained for the J1–J2 model with parameters J1/kB = −38.33 K and J2/kB = 29.48 K (gb = 2.07, ga,c = 1.99). In contrast to the previously used model (a uniform antiferromagnetic spin chain system with J1/kB = 21.4 K (gb = 2.28, ga,c = 2.18)), this improved result allows one to consider the object under study as a zigzag chain system with a dominant ferromagnetic exchange between the nearest neighbors and an antiferromagnetic interaction between the next-nearest neighbors.
Development of ion beam figuring system with electrostatic deflection for ultraprecise X-ray reflective optics
Authors: Yamada Jumpei , Matsuyama Satoshi , Sano Yasuhisa , Yamauchi Kazuto
Published: September 2015

We developed an ion beam figuring system that utilizes electrostatic deflection. The system can produce an arbitrary shape by deterministically scanning the ion beam. The scan of the ion beam, which can be precisely controlled using only an electrical signal, enables us to avoid degradation of the mirror shape caused by imperfect acceleration or deceleration of a mechanically scanning stage. Additionally, this surface figuring method can easily be combined with X-ray metrology because the workpiece remains fixed during the figuring. We evaluated the figuring accuracy of the system by fabricating a plano-elliptical mirror for X-ray focusing. A mirror with a shape error of 1.4 nm root mean square (RMS) with a maximum removal depth of 992 nm, which corresponds to figuring accuracy of 0.14% RMS, was achieved. After the second shape corrections, an elliptical shape with a shape error of approximately 1 nm peak-to-valley, 0.48 nm RMS could be fabricated. Then, the mirror surface was smoothed by a low-energy ion beam. Consequently, a micro-roughness of 0.117 nm RMS, measured by atomic force microscopy, was achieved over an area of 1 × 1 μm2.
The spectral imaging facility: Setup characterization
Authors: De Angelis Simone , Ammannito Eleonora , Di Iorio Tatiana , De Sanctis Maria Cristina , Manzari Paola Olga , Liberati Fabrizio , Tarchi Fabio , Dami Michele , Olivieri Monica , Pompei Carlo , Mugnuolo Raffaele
Published: September 2015

The SPectral IMager (SPIM) facility is a laboratory visible infrared spectrometer developed to support space borne observations of rocky bodies of the solar system. Currently, this laboratory setup is used to support the DAWN mission, which is in its journey towards the asteroid 1-Ceres, and to support the 2018 Exo-Mars mission in the spectral investigation of the Martian subsurface. The main part of this setup is an imaging spectrometer that is a spare of the DAWN visible infrared spectrometer. The spectrometer has been assembled and calibrated at Selex ES and then installed in the facility developed at the INAF-IAPS laboratory in Rome. The goal of SPIM is to collect data to build spectral libraries for the interpretation of the space borne and in situ hyperspectral measurements of planetary materials. Given its very high spatial resolution combined with the imaging capability, this instrument can also help in the detailed study of minerals and rocks. In this paper, the instrument setup is first described, and then a series of test measurements, aimed to the characterization of the main subsystems, are reported. In particular, laboratory tests have been performed concerning (i) the radiation sources, (ii) the reference targets, and (iii) linearity of detector response; the instrumental imaging artifacts have also been investigated.
Strain-dependent damping in nanomechanical resonators from thin MoS2 crystals
Authors: Kramer E. , van Dorp J. , van Leeuwen R. , Venstra W. J.
Published: September 2015

We investigate the effect of mechanical strain on the dynamics of thin MoS2 nanodrum resonators. Using a piezoelectric crystal, compressive and tensile biaxial strain is induced in initially flat and buckled devices. In the flat device, we observe a remarkable strain-dependence of the resonance line width, while the change in the resonance frequency is relatively small. In the buckled device, the strain-dependence of the damping is less pronounced, and a clear hysteresis is observed. The experiment suggests that geometric imperfections, such as microscopic wrinkles, could play a role in the strong dissipation observed in nanoresonators fabricated from 2-D materials.
Screens versus microarrays for ruggedized retarding potential analyzers
Authors: Enloe C. L. , Amatucci W. E. , McHarg M. G. , Balthazor R. L.
Published: September 2015

An array of highly miniaturized electrostatic lenses is shown to be a viable replacement for meshes or screens in a retarding potential analyzer (RPA) where mechanical ruggedness or the ability to intercept large currents of energetic particles is desirable. Data from a prototype device are presented cross-calibrated with a traditional planar RPA indicating how the so-called microarray configuration avoids energy-dependent transparency (either reduced or enhanced) associated with meshes or screens while providing accurate energy analysis with reasonable energy resolution. In contrast, another ruggedized configuration employing a screen is presented, showing the severity of energy-dependent enhanced transparency, verified by numerical simulation.
Acoustic metamaterial with negative mass density in water
Authors: Chen Huaijun , Zhai Shilong , Ding Changlin , Luo Chunrong , Zhao Xiaopeng
Published: September 2015

A two-dimensional (2D) acoustic metamaterial (AM) with negative effective mass density in water is designed by periodically arranging hollow tube “meta-atoms.” Experimental and simulated results demonstrate that transmission dips accompanied with inverse phases are presented in the transmission spectra of the 2D AM at the ultrasonic frequency band. Effective parameters extracted from the experimental measured transmission and reflection coefficients of the 2D AM show that the effective mass density and refractive index are negative near the dip frequency range of 35.31–35.94 kHz. The simulation also shows the negative response in the 2D AM. Due to the excellent properties, the 2D AM is appealing for the potential applications in areas such as subwavelength imaging, ultrasonic cloaking in water, and so on.
A new apparatus design for high temperature (up to 950 °C) quasi-elastic neutron scattering in a controlled gaseous environment
Authors: al-Wahish Amal , Armitage D. , al-Binni U. , Hill B. , Mills R. , Jalarvo N. , Santodonato L. , Herwig K. W. , Mandrus D.
Published: September 2015

A design for a sample cell system suitable for high temperature Quasi-Elastic Neutron Scattering (QENS) experiments is presented. The apparatus was developed at the Spallation Neutron Source in Oak Ridge National Lab where it is currently in use. The design provides a special sample cell environment under controlled humid or dry gas flow over a wide range of temperature up to 950 °C. Using such a cell, chemical, dynamical, and physical changes can be studied in situ under various operating conditions. While the cell combined with portable automated gas environment system is especially useful for in situ studies of microscopic dynamics under operational conditions that are similar to those of solid oxide fuel cells, it can additionally be used to study a wide variety of materials, such as high temperature proton conductors. The cell can also be used in many different neutron experiments when a suitable sample holder material is selected. The sample cell system has recently been used to reveal fast dynamic processes in quasi-elastic neutron scattering experiments, which standard probes (such as electrochemical impedance spectroscopy) could not detect. In this work, we outline the design of the sample cell system and present results demonstrating its abilities in high temperature QENS experiments.
Characterization of individual molecular adsorption geometries by atomic force microscopy: Cu-TCPP on rutile TiO2 (110)
Authors: Jöhr Res , Hinaut Antoine , Pawlak Rémy , Sadeghi Ali , Saha Santanu , Goedecker Stefan , Such Bartosz , Szymonski Marek , Meyer Ernst , Glatzel Thilo
Published: September 2015

Functionalized materials consisting of inorganic substrates with organic adsorbates play an increasing role in emerging technologies like molecular electronics or hybrid photovoltaics. For such applications, the adsorption geometry of the molecules under operating conditions, e.g., ambient temperature, is crucial because it influences the electronic properties of the interface, which in turn determine the device performance. So far detailed experimental characterization of adsorbates at room temperature has mainly been done using a combination of complementary methods like photoelectron spectroscopy together with scanning tunneling microscopy. However, this approach is limited to ensembles of adsorbates. In this paper, we show that the characterization of individual molecules at room temperature, comprising the determination of the adsorption configuration and the electrostatic interaction with the surface, can be achieved experimentally by atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM). We demonstrate this by identifying two different adsorption configurations of isolated copper(ii) meso-tetra (4-carboxyphenyl) porphyrin (Cu-TCPP) on rutile TiO2 (110) in ultra-high vacuum. The local contact potential difference measured by KPFM indicates an interfacial dipole due to electron transfer from the Cu-TCPP to the TiO2. The experimental results are verified by state-of-the-art first principles calculations. We note that the improvement of the AFM resolution, achieved in this work, is crucial for such accurate calculations. Therefore, high resolution AFM at room temperature is promising for significantly promoting the understanding of molecular adsorption.
A mechanistic study of impurity segregation at silicon grain boundaries
Authors: Käshammer Peter , Sinno Talid
Published: September 2015

The segregation behavior of carbon and oxygen atoms at various silicon grain boundaries was studied using a combination of atomistic simulation and analytical modeling. First, quasi-lattice Grand Canonical Monte Carlo simulations were used to compute segregation isotherms as a function of grain boundary type, impurity atom loading level, and temperature. Next, the atomistic results were employed to regress different analytical segregation models and extract thermodynamic and structural properties. The multilayer Brunauer–Emmett–Teller (BET) isotherm was found to quantitatively capture all the simulation conditions probed in this work, while simpler, single layer models such as the Langmuir-McLean model did not. Some of the BET parameters, namely, the binding free energy of the first adsorption layer and the impurity holding capacity of each layer, were tested for correlation with various measures of grain boundary structure and/or mechanical properties. It was found that certain measures of the atomistic stress distribution correlate strongly with the first-layer binding free energy for substitutional carbon atoms, while common grain boundary identifiers such as sigma value and energy density are not useful in this regard. Preliminary analysis of the more complex case of interstitial oxygen segregation showed that similar measures based on atomistic stress also may be useful here, but more systematic correlative studies are needed to develop a comprehensive picture.
Fabrication of microchannels in fused silica using femtosecond Bessel beams
Authors: Yashunin D. A. , Malkov Yu. A. , Mochalov L. A. , Stepanov A. N.
Published: September 2015

Extended birefringent waveguiding microchannels up to 15 mm long were created inside fused silica by single-pulse irradiation with femtosecond Bessel beams. The birefringent refractive index change of 2–4 × 10−4 is attributed to residual mechanical stress. The microchannels were chemically etched in KOH solution to produce 15 mm long microcapillaries with smooth walls and a high aspect ratio of 1:250. Bessel beams provide higher speed of material processing compared to conventional multipulse femtosecond laser micromachining techniques and permit simple control of the optical axis direction of the birefringent waveguides, which is important for practical applications [Corrielli et al., “Rotated waveplates in integrated waveguide optics,” Nat. Commun. 5, 4249 (2014)].
Fourier type transforms on Lie symmetry groups
Authors: Craddock Mark
Published: September 2015

In this paper, we construct operators on a Lie symmetry group which may be regarded as Fourier transforms. Essentially, we integrate solutions generated by Lie symmetries against suitable test functions. We show that this idea leads to a powerful method for solving Cauchy problems for parabolic and hyperbolic equations in two and higher dimensions. We also discuss applications to the elliptic case.
Self-adjointness of deformed unbounded operators
Authors: Much Albert
Published: September 2015

We consider deformations of unbounded operators by using the novel construction tool of warped convolutions. By using the Kato-Rellich theorem, we show that unbounded self-adjoint deformed operators are self-adjoint if they satisfy a certain condition. This condition proves itself to be necessary for the oscillatory integral to be well-defined. Moreover, different proofs are given for self-adjointness of deformed unbounded operators in the context of quantum mechanics and quantum field theory.
Using stepped anvils to make even insulation layers in laser-heated diamond-anvil cell samples
Authors: Du Zhixue , Gu Tingting , Dobrosavljevic Vasilije , Weir Samuel T. , Falabella Steve , Lee Kanani K. M.
Published: September 2015

We describe a method to make even insulation layers for high-pressure laser-heated diamond-anvil cell samples using stepped anvils. The method works for both single-sided and double-sided laser heating using solid or fluid insulation. The stepped anvils are used as matched pairs or paired with a flat culet anvil to make gasket insulation layers and not actually used at high pressures; thus, their longevity is ensured. We compare the radial temperature gradients and Soret diffusion of iron between self-insulating samples and samples produced with stepped anvils and find that less pronounced Soret diffusion occurs in samples with even insulation layers produced by stepped anvils.
The Nature of the Glassy Phase in 4He Crystals
Authors: Antsygina T. N. , Poltavskaya M. I. , Chishko K. A.
Published: September 2015

A model of a close-packed polytype with a random stacking fault structure is used to interpret the anomalies of the thermodynamic properties of the disordered (glassy) phase in solid HCP 4He in the so-called supersolid state. The temperature dependence of the phonon pressure is calculated theoretically, and compared to experimental data. A quantitative agreement between the theory and the experiment is achieved.
Path integral molecular dynamics within the grand canonical-like adaptive resolution technique: Simulation of liquid water
Authors: Agarwal Animesh , Delle Site Luigi
Published: September 2015

Quantum effects due to the spatial delocalization of light atoms are treated in molecular simulation via the path integral technique. Among several methods, Path Integral (PI) Molecular Dynamics (MD) is nowadays a powerful tool to investigate properties induced by spatial delocalization of atoms; however, computationally this technique is very demanding. The above mentioned limitation implies the restriction of PIMD applications to relatively small systems and short time scales. One of the possible solutions to overcome size and time limitation is to introduce PIMD algorithms into the Adaptive Resolution Simulation Scheme (AdResS). AdResS requires a relatively small region treated at path integral level and embeds it into a large molecular reservoir consisting of generic spherical coarse grained molecules. It was previously shown that the realization of the idea above, at a simple level, produced reasonable results for toy systems or simple/test systems like liquid parahydrogen. Encouraged by previous results, in this paper, we show the simulation of liquid water at room conditions where AdResS, in its latest and more accurate Grand-Canonical-like version (GC-AdResS), is merged with two of the most relevant PIMD techniques available in the literature. The comparison of our results with those reported in the literature and/or with those obtained from full PIMD simulations shows a highly satisfactory agreement.
Regarding the relation between the photon-roton spectrum and the single-particle excitation spectrum in liquids with Bose-Einstein condensate
Authors: Bobrov V. B. , Zagorodny A. G. , Trigger S. A.
Published: September 2015

An analysis of the existing theoretical ideas as to the relationship between the spectrum of collective density excitations and the spectrum of single-particle excitations in liquids with a Bose-Einstein condensate. Using available experimental results, we examine the problem of the relationship between the collective phonon-roton excitations in different liquids, and the Bose-Einstein condensate.
Phonon transport of energy in nanostructures containing two metallic layers
Authors: Bezuglyj A. I.
Published: September 2015

We examine steady-state heating of a system consisting of two metallic layers M1 and M2 separated by a dielectric spacer I. It is assumed that powers W1 and W2 are absorbed in the layers and the bulk dielectric substrate upon which the M1/I/M2 system lies is a thermostat. Phonon transport of heat in M1/I/M2 systems is analyzed using a kinetic equation for the phonon distribution function, and the dependence of the electron temperatures T1 and T2 of the layers on W1 and W2 is found. The limiting cases of thick and thin layers are examined in a real experimental situation where one of the layers is heated and the other serves as a thermometer. The theoretical results are compared with the experiment.
Asymmetric conduction in biological nanopores created by high-intensity, nanosecond pulsing: Inference on internal charge lining the membrane based on a model study
Authors: Joshi R. P. , Qiu H.
Published: September 2015

Nanosecond, high-intensity electric pulses have been reported to open rectifying pores in biological cell membranes. The present goal is to qualitatively understand and analyze the experimental current-voltage (I-V) data. Here, nanopore transport is probed using a numerical method and on the basis of an analytical model. Our results show that geometric asymmetry in the nanopore would not yield asymmetry in the I-V characteristics. However, positive surface charge lining the pore could produce characteristics that compare well with data from patch-clamp measurements, and a value of ∼0.02 C/m2 is predicted from the numerical calculations.
Measurements and simulations of the optical gain and anti-reflection coating modal reflectivity in quantum cascade lasers with multiple active region stacks
Authors: Bidaux Y. , Terazzi R. , Bismuto A. , Gresch T. , Blaser S. , Muller A. , Faist J.
Published: September 2015

We report spectrally resolved gain measurements and simulations for quantum cascade lasers (QCLs) composed of multiple heterogeneous stacks designed for broadband emission in the mid-infrared. The measurement method is first demonstrated on a reference single active region QCL based on a double-phonon resonance design emitting at 7.8 μm. It is then extended to a three-stack active region based on bound-to-continuum designs with a broadband emission range from 7.5 to 10.5 μm. A tight agreement is found with simulations based on a density matrix model. The latter implements exhaustive microscopic scattering and dephasing sources with virtually no fitting parameters. The quantitative agreement is furthermore assessed by measuring gain coefficients obtained by studying the threshold current dependence with the cavity length. These results are particularly relevant to understand fundamental gain mechanisms in complex semiconductor heterostructure QCLs and to move towards efficient gain engineering. Finally, the method is extended to the measurement of the modal reflectivity of an anti-reflection coating deposited on the front facet of the broadband QCL.
Experimentally generating any desired partially coherent Schell-model source using phase-only control
Authors: Hyde Milo W. , Basu Santasri , Voelz David G. , Xiao Xifeng
Published: September 2015

A technique is presented to produce any desired partially coherent Schell-model source using a single phase-only liquid-crystal spatial light modulator (SLM). Existing methods use SLMs in combination with amplitude filters to manipulate the phase and amplitude of an initially coherent source. The technique presented here controls both the phase and amplitude using a single SLM, thereby making the amplitude filters unnecessary. This simplifies the optical setup and significantly increases the utility and flexibility of the resulting system. The analytical development of the technique is presented and discussed. To validate the proposed approach, experimental results of three partially coherent Schell-model sources are presented and analyzed. A brief discussion of possible applications is provided in closing.
Optical properties of single wurtzite/zinc-blende ZnSe nanowires grown at low temperature
Authors: Zannier V. , Cremel T. , Artioli A. , Ferrand D. , Kheng K. , Grillo V. , Rubini S.
Published: September 2015

ZnSe nanowires with a dominant wurtzite structure have been grown at low temperature (300 °C) by molecular beam epitaxy assisted by solid Au nanoparticles. The nanowires emission is polarized perpendicularly to their axis in agreement with the wurtzite selection rules. Alternations of wurtzite and zinc-blende regions have been observed by transmission electron microscopy, and their impact on the nanowires optical properties has been studied by microphotoluminescence. The nanowires show a dominant intense near-band-edge emission as well as the ZnSe wurtzite free exciton line. A type II band alignment between zinc-blende and wurtzite ZnSe is evidenced by time-resolved photoluminescence. From this measurement, we deduce values for the conduction and valence band offsets of 98 and 50 meV, respectively.
Vertical coupling of laser glass microspheres to buried silicon nitride ellipses and waveguides
Authors: Navarro-Urrios D. , Ramírez J. M. , Capuj N. E. , Berencén Y. , Garrido B. , Tredicucci A.
Published: September 2015

We demonstrate the integration of Nd3+ doped barium-titanium-silicate microsphere lasers with a silicon nitride photonic platform. Devices with two different geometrical configurations for extracting the laser light to buried waveguides have been fabricated and characterized. The first configuration relies on a standard coupling scheme, where the microspheres are placed over strip waveguides. The second is based on a buried elliptical geometry whose working principle is that of an elliptical mirror. In the latter case, the input of a strip waveguide is placed on one focus of the ellipse, while a lasing microsphere is placed on top of the other focus. The fabricated elliptical geometry (ellipticity = 0.9) presents a light collecting capacity that is 50% greater than that of the standard waveguide coupling configuration and could be further improved by increasing the ellipticity. Moreover, since the dimensions of the spheres are much smaller than those of the ellipses, surface planarization is not required. On the contrary, we show that the absence of a planarization step strongly damages the microsphere lasing performance in the standard configuration.