bluuebunny/crossref_metadata_2025 huggingface dataset:
Short contacts of the sulphur atoms of a 1,2,3,5-dithiadiazolyl dimer with triphenylstibine: first co-crystal with an aromatic compound
Authors: Boeré René T.
Published: March 2016

Co-crystallization of aromatic compounds with neutral dithiadiazolyl dimers has not previously succeeded. There is great scope here for crystal engineering using mutually compatible components.
Tuning the spontaneous formation kinetics of caffeine : malonic acid co-crystals
Authors: Nartowski K. P. , Khimyak Y. Z. , Berry D. J.
Published: March 2016

It has previously been reported that the caffeine : malonic acid co-crystal system forms spontaneously upon the contact of the two materials, here we explore the mechanism of this formation and control the kinetics to enable us to monitor the conversion.
An intensive dispersion and synchronous assembly of single-walled carbon nanotubes in a surfactant–oil–water association system
Authors: Zhang Yan , Li Dechun , Wu Lin , Zhou Liang , Du Yanan , Wang Meng , Li Ying
Published: March 2016

An intensive dispersion and synchronous assembly of single-walled carbon nanotubes were achieved using a surfactant–oil–water association system.
A medium range order structural connection to the configurational heat capacity of borate–silicate mixed glasses
Authors: Liu Hao , Smedskjaer Morten M. , Tao Haizheng , Jensen Lars R. , Zhao Xiujian , Yue Yuanzheng
Published: March 2016

Intermediate range order (IRO) structures have a major impact on the composition dependence of the configurational heat capacity of glass.
A theoretical study on superalkali-doped nanocages: unique inorganic electrides with high stability, deep-ultraviolet transparency, and a considerable nonlinear optical response
Authors: Sun Wei-Ming , Li Xiang-Hui , Wu Di , Li Ying , He Hui-Min , Li Zhi-Ru , Chen Jing-Hua , Li Chun-Yan
Published: March 2016

A series of stable inorganic electrides with a large nonlinear optical response and deep-ultraviolet transparency were theoretically designed and investigated.
Improving the stability and inertness of Cu(ii) and Cu(i) complexes with methylthiazolyl ligands by tuning the macrocyclic structure
Authors: Le Fur Mariane , Beyler Maryline , Le Poul Nicolas , Lima Luís M. P. , Le Mest Yves , Delgado Rita , Platas-Iglesias Carlos , Patinec Véronique , Tripier Raphaël
Published: March 2016

A tacn bearing methylthiazolyl arms was synthesized and its copper(ii) and (i) complexes showed excellent stability and inertness in aqueous medium.
Investigations on local structures in new Bi2−2xLa2xUO6 (x = 0–0.05) solid solutions: a combined XRD, EXAFS, PL and EPR study
Authors: Sanyal Kaushik , Pathak Nimai , Yadav Ashok Kumar , Kanrar Buddhadev , Kadam Ramakant Mahadeo , Jha Shambhu Nath , Bhattacharya Dibyendu , Misra N. L.
Published: March 2016

During the formation of Bi2−2xLa2xUO6 (x = 0–0.05), La+3 ions replace Bi+3 in the Bi2UO6 lattice with the creation of some oxygen vacancies.
Orbitally induced hierarchy of exchange interactions in the zigzag antiferromagnetic state of honeycomb silver delafossite Ag3Co2SbO6
Authors: Zvereva E. A. , Stratan M. I. , Ushakov A. V. , Nalbandyan V. B. , Shukaev I. L. , Silhanek A. V. , Abdel-Hafiez M. , Streltsov S. V. , Vasiliev A. N.
Published: March 2016

The revised crystal structure, static and dynamic magnetic properties and GGA+U calculations for layered honeycomb-lattice silver delafossite Ag3Co2SbO6 are reported.
Towards microfluidic sperm refinement: impedance-based analysis and sorting of sperm cells
Authors: de Wagenaar B. , Dekker S. , de Boer H. L. , Bomer J. G. , Olthuis W. , van den Berg A. , Segerink L. I.
Published: March 2016

The use of high quality semen for artificial insemination in the livestock industry is essential for successful outcome.
Enlarging the chemical space of anti-leishmanials: a structure–activity relationship study of peptoids against Leishmania mexicana, a causative agent of cutaneous leishmaniasis
Authors: Bolt H. L. , Eggimann G. A. , Denny Paul W. , Cobb Steven L.
Published: March 2016

Peptoids with promising activity against intracellularLeishmania mexicanaamastigotes have been identified.
Modelling flavoenzymatic charge transfer events: development of catalytic indole deuteration strategies
Authors: Murray Alexander T. , Challinor Jonathan D. , Gulácsy Christina E. , Lujan Cristina , Hatcher Lauren E. , Pudney Christopher R. , Raithby Paul R. , John Matthew P. , Carbery David R.
Published: March 2016

The formation and chemistry of flavin–indole charge transfer (CT) complexes has been studied using a model cationic flavin.
C–ON bond homolysis in alkoxyamines. Part 12: the effect of the para-substituent in the 1-phenylethyl fragment
Authors: Audran Gérard , Brémond Paul , Joly Jean-Patrick , Marque Sylvain R. A. , Yamasaki Toshihide
Published: March 2016

The application of alkoxyamines as initiators/controllers in nitroxide mediated polymerization and as agents for theranostics requires the development of switchable (from stable one to labile one) alkoxyamines.
Correction: A new methylviologen-templated zinc gallophosphate zeolite with photo-/thermochromism, fluorescent and photoelectric properties
Authors: Tao Chunyao , Wu Junbiao , Yan Yan , Shi Chao , Li Jiyang
Published: March 2016

Correction for ‘A new methylviologen-templated zinc gallophosphate zeolite with photo-/thermochromism, fluorescent and photoelectric properties’ by Chunyao Tao, et al., Inorg. Chem. Front., 2016, DOI: 10.1039/c5qi00283d.
The effect of block copolymer additives for a highly active polymeric metal-free oxygen reduction electrode
Authors: Pering Samuel R. , Nicholas James A. , Bayatsarmadi Bita , Evans Drew , Fabretto Manrico , Blencowe Anton , Murphy Peter J. , Talemi Pejman
Published: March 2016

The effect of triblock copolymer additives on polymeric ORR electrodes is studied and a highly efficient polymeric electrode is developed.
Schottky barrier tuning in semiconducting ZnO and BaTiO3 hybrid heterostructures shows dielectric and electrical anisotropy
Authors: Aepuru Radhamanohar , Kankash Shivani , Panda H. S.
Published: March 2016

Polygonal nanosize BaTiO3 and modified BaTiO3 with carbon are prepared using a modified hydrothermal process and utilized as solutes to set up bimodal hollow zinc oxide (ZnO) heterostructures.
Impact of the functional group in the polyanion of single lithium-ion conducting polymer electrolytes on the stability of lithium metal electrodes
Authors: Ma Qiang , Xia Yu , Feng Wenfang , Nie Jin , Hu Yong-Sheng , Li Hong , Huang Xuejie , Chen Liquan , Armand Michel , Zhou Zhibin
Published: March 2016

The functional group in the polyanion plays a key role in improving the interfacial stability of the Li metal electrode.
Electrochemical reduction La(iii) on W and Mg electrodes: application to prepare Mg–La and Mg–Li–La alloys in LiCl–KCl melts
Authors: Ji De-Bin , Yin Tai-Qi , Yan Yong-De , Zhang Mi-Lin , Wang Pu , Liu Yu-Hui , Zheng Jia-Ning , Xue Yun , Jing Xiao-Yan , Han Wei
Published: March 2016

The electrochemical behavior of La(iii) ions was studied by different electrochemical measurements in LiCl–KCl–MgCl2melts on a W electrode and in LiCl–KCl melts on an active Mg electrode at 873 K, respectively.
Nano-silver enhanced luminescence of Er3+ ions embedded in tellurite glass, vitro-ceramic and ceramic: impact of heat treatment
Authors: Fares Hssen , Stambouli Wissal , Elhouichet Habib , Gelloz Bernard , Férid Mokhtar
Published: March 2016

Tellurite glasses co-activated with erbium ions and silver nanoparticles (Ag NPs) are prepared using melt quenching technique.
Evaluation of Sm0.95Ba0.05Fe0.95Ru0.05O3 as a potential cathode material for solid oxide fuel cells
Authors: Fan Weiwei , Sun Zhu , Wang Junkai , Zhou Jun , Wu Kai , Cheng Yonghong
Published: March 2016

A new family of Sm0.95Ba0.05Fe0.95Ru0.05O3 perovskite is synthesized via citric-acid method and investigated as prospective cathode material for SOFCs.
A simple and effective way to fabricate mechanical robust superhydrophobic surfaces
Authors: Tian Hao , Wang Fajun , Ge Sijie , Ou Junfei , Li Wen , Yu Shijin
Published: March 2016

The SH surface is mechanical robust against abrading, finger touch, brushing and scratching, as well as high pressure water impacting.
Gold nanorods with conjugated polymer ligands: sintering-free conductive inks for printed electronics
Authors: Reiser B. , González-García L. , Kanelidis I. , Maurer J. H. M. , Kraus T.
Published: March 2016

A straightforward route to hybrid nanostructures of metal cores with conductive polymers and their application as sintering-free inks is described.
[d]-Carbon–carbon double bond engineering in diazaphosphepines: a pathway to modulate the chemical and electronic structures of heteropines
Authors: Ren Yi , Sezen Melda , Guo Fang , Jäkle Frieder , Loo Yueh-Lin
Published: March 2016

We report the first examples of 7-membered diazaphosphepines using phosphorus–amine (P–N) chemistry.
Tuning the central fused ring and terminal units to improve the photovoltaic performance of Ar(A–D)2 type small molecules in solution-processed organic solar cells
Authors: Chen Jianhua , Duan Linrui , Xiao Manjun , Wang Qiong , Liu Bin , Xia Hao , Yang Renqiang , Zhu Weiguo
Published: March 2016

A series of Ar(A–D)2 type small molecules containing a pyrene core were synthesized. A significantly improved power conversion efficiency of 5.88% was obtained for ThDPP2Py based organic solar cells.
Three-dimensional freestanding hierarchically porous carbon materials as binder-free electrodes for supercapacitors: high capacitive property and long-term cycling stability
Authors: Miao Fujun , Shao Changlu , Li Xinghua , Wang Kexin , Lu Na , Liu Yichun
Published: March 2016

Three-dimensional freestanding hierarchically porous carbon was successfully fabricated and assembled in a symmetric supercapacitor presenting outstanding electrochemical performance.
Mechanical loading inhibits hypertrophy in chondrogenically differentiating hMSCs within a biomimetic hydrogel
Authors: Aisenbrey E. A. , Bryant S. J.
Published: March 2016

Three dimensional hydrogels are a promising vehicle for delivery of adult human bone-marrow derived mesenchymal stem cells (hMSCs) for cartilage tissue engineering.
Thermochemistry study and improved thermal stability of Yb14MnSb11 alloyed by Ln3+ (La–Lu)
Authors: Vasilyeva I. G. , Nikolaev R. E. , Abdusaljamova M. N. , Kauzlarich S. M.
Published: March 2016

Increase in melting points of Yb13.6Ln0.4MnSb11 due to the Ln ordered distribution and ionic bond strengthening.
Surface treatment-assisted switchable transfer printing on polydimethylsiloxane films
Authors: Wang Juanjuan , Xie Jixun , Zong Chuanyong , Han Xue , Ji Haipeng , Zhao Jingxin , Lu Conghua
Published: March 2016

Switchable transfer printing with different “soft/hard” combinations of the PDMS stamp and substrate assisted by surface oxidation.
Future perspectives toward the early definition of a multivariate decision‐support scheme employed in clinical decision making for senior citizens
Authors: Frantzidis Christos A. , Gilou Sotiria , Billis Antonis , Karagianni Maria , Bratsas Charalampos D. , Bamidis Panagiotis
Published: March 2016

Recent neuroscientific studies focused on the identification of pathological neurophysiological patterns (emotions, geriatric depression, memory impairment and sleep disturbances) through computerised clinical decision‐support systems. Almost all these research attempts employed either resting‐state condition (e.g. eyes‐closed) or event‐related potentials extracted during a cognitive task known to be affected by the disease under consideration. This Letter reviews existing data mining techniques and aims to enhance their robustness by proposing a holistic decision framework dealing with comorbidities and early symptoms’ identification, while it could be applied in realistic occasions. Multivariate features are elicited and fused in order to be compared with average activities characteristic of each neuropathology group. A proposed model of the specific cognitive function which may be based on previous findings (a priori information) and/or validated by current experimental data should be then formed. So, the proposed scheme facilitates the early identification and prevention of neurodegenerative phenomena. Neurophysiological semantic annotation is hypothesised to enhance the importance of the proposed framework in facilitating the personalised healthcare of the information society and medical informatics research community.
Direct numerical simulation of sharkskin denticles in turbulent channel flow
Authors: Boomsma A. , Sotiropoulos F.
Published: March 2016

The hydrodynamic function of sharkskin has been under investigation for the past 30 years. Current literature conflicts on whether sharkskin is able to reduce skin friction similar to riblets. To contribute insights toward reconciling these conflicting views, direct numerical simulations are carried out to obtain detailed flow fields around realistic denticles. A sharp interface immersed boundary method is employed to simulate two arrangements of actual sharkskin denticles (from Isurus oxyrinchus) in a turbulent boundary layer at Reτ ≈ 180. For comparison, turbulent flow over drag-reducing scalloped riblets is also simulated with similar flow conditions and with the same numerical method. Although the denticles resemble riblets, both sharkskin arrangements increase total drag by 44%-50%, while the riblets reduce drag by 5%. Analysis of the simulated flow fields shows that the turbulent flow around denticles is highly three-dimensional and separated, with 25% of the total drag being form drag. The complex three-dimensional shape of the denticles gives rise to a mean flow dominated by strong secondary flows in sharp contrast with the mean flow generated by riblets, which is largely two-dimensional. The so resulting three-dimensionality of sharkskin flows leads to an increase in the magnitude of the turbulent statistics near the denticles, which further contributes to increasing the total drag. The simulations also show that, at least for the simulated arrangements, sharkskin, in sharp contrast with drag-reducing riblets, is unable to isolate high shear stress near denticle ridges causing a significant portion of the denticle surface to be exposed to high mean shear.
Enhanced voltage-controlled magnetic anisotropy in magnetic tunnel junctions with an MgO/PZT/MgO tunnel barrier
Authors: Chien Diana , Li Xiang , Wong Kin , Zurbuchen Mark A. , Robbennolt Shauna , Yu Guoqiang , Tolbert Sarah , Kioussis Nicholas , Khalili Amiri Pedram , Wang Kang L. , Chang Jane P.
Published: March 2016

Compared with current-controlled magnetization switching in a perpendicular magnetic tunnel junction (MTJ), electric field- or voltage-induced magnetization switching reduces the writing energy of the memory cell, which also results in increased memory density. In this work, an ultra-thin PZT film with high dielectric constant was integrated into the tunneling oxide layer to enhance the voltage-controlled magnetic anisotropy (VCMA) effect. The growth of MTJ stacks with an MgO/PZT/MgO tunnel barrier was performed using a combination of sputtering and atomic layer deposition techniques. The fabricated MTJs with the MgO/PZT/MgO barrier demonstrate a VCMA coefficient, which is ∼40% higher (19.8 ± 1.3 fJ/V m) than the control sample MTJs with an MgO barrier (14.3 ± 2.7 fJ/V m). The MTJs with the MgO/PZT/MgO barrier also possess a sizeable tunneling magnetoresistance (TMR) of more than 50% at room temperature, comparable to the control MTJs with an MgO barrier. The TMR and enhanced VCMA effect demonstrated simultaneously in this work make the MgO/PZT/MgO barrier-based MTJs potential candidates for future voltage-controlled, ultralow-power, and high-density magnetic random access memory devices.
Analysis of hydrogen plasma in a microwave plasma chemical vapor deposition reactor
Authors: Shivkumar G. , Tholeti S. S. , Alrefae M. A. , Fisher T. S. , Alexeenko A. A.
Published: March 2016

The aim of this work is to build a numerical model of hydrogen plasma inside a microwave plasma chemical vapor deposition system. This model will help in understanding and optimizing the conditions for the growth of carbon nanostructures. A 2D axisymmetric model of the system is implemented using the finite element high frequency Maxwell solver and the heat transfer solver in COMSOL Multiphysics. The system is modeled to study variation in parameters with reactor geometry, microwave power, and gas pressure. The results are compared with experimental measurements from the Q-branch of the H2 Fulcher band of hydrogen using an optical emission spectroscopy technique. The parameter γ in Füner's model is calibrated to match experimental observations at a power of 500 W and 30 Torr. Good agreement is found between the modeling and experimental results for a wide range of powers and pressures. The gas temperature exhibits a weak dependence on power and a strong dependence on gas pressure. The inclusion of a vertical dielectric pillar that concentrates the plasma increases the maximum electron temperature by 70%, the maximum gas temperature by 50%, and the maximum electron number density by 70% when compared to conditions without the pillar at 500 W and 30 Torr. Experimental observations also indicate intensified plasma with the inclusion of a pillar.
Structural and optical properties of the naked and passivated Al5Au5 bimetallic nanoclusters
Authors: Grande-Aztatzi Rafael , Formoso Elena , Mercero Jose M. , Matxain Jon M. , Grabowski Slawomir J. , Ugalde Jesus M.
Published: March 2016

The structural and optical properties of both the naked and passivated bimetallic Al5Au5 nanoclusters have been analyzed based on data obtained from ab initio density functional theory and quantum molecular dynamics simulations. It has been found that the Al5Au5 nanocluster possesses a hollow shaped minimum energy structure with segregated Al and Au layered domains, the former representing the electrophilic domain and the latter the nucleophilic domain. In particular, it has been shown that alkali metal cations attach in the nucleophilic domain and hop from one Au site to the next one in the picoseconds time scale, while anions are bound tightly to the Al atoms of the electrophilic domain. Simulating annealing studies are very suggestive of the proneness of the nanocluster towards coalescence into large cluster units, when the cluster is left unprotected by appropriate ligands. Further passivation studies with NaF salt suggest, nonetheless, the possibility of the isolation of the Al5Au5 cluster in molten salts or ionic liquids.
Efficient magnetic fields for supporting toroidal plasmas
Authors: Landreman Matt , Boozer Allen H.
Published: March 2016

The magnetic field that supports tokamak and stellarator plasmas must be produced by coils well separated from the plasma. However, the larger the separation, the more difficult it is to produce a given magnetic field in the plasma region, so plasma configurations should be chosen that can be supported as efficiently as possible by distant coils. The efficiency of an externally generated magnetic field is a measure of the field's shaping component magnitude at the plasma compared to the magnitude near the coils; the efficiency of a plasma equilibrium can be measured using the efficiency of the required external shaping field. Counterintuitively, plasma shapes with low curvature and spectral width may have low efficiency, whereas plasma shapes with sharp edges may have high efficiency. Two precise measures of magnetic field efficiency, which correctly identify such differences in difficulty, will be examined. These measures, which can be expressed as matrices, relate the externally produced normal magnetic field on the plasma surface to the either the normal field or current on a distant control surface. A singular value decomposition (SVD) of either matrix yields an efficiency ordered basis for the magnetic field distributions. Calculations are carried out for both tokamak and stellarator cases. For axisymmetric surfaces with circular cross-section, the SVD is calculated analytically, and the range of poloidal and toroidal mode numbers that can be controlled to a given desired level is determined. If formulated properly, these efficiency measures are independent of the coordinates used to parameterize the surfaces.
Generalized zeta function representation of groups and 2-dimensional topological Yang-Mills theory: The example of GL(2, 𝔽q) and PGL(2, 𝔽q)
Authors: Roche Ph.
Published: March 2016

We recall the relation between zeta function representation of groups and two-dimensional topological Yang-Mills theory through Mednikh formula. We prove various generalisations of Mednikh formulas and define generalization of zeta function representations of groups. We compute some of these functions in the case of the finite group GL(2, 𝔽q) and PGL(2, 𝔽q). We recall the table characters of these groups for any q, compute the Frobenius-Schur indicator of their irreducible representations, and give the explicit structure of their fusion rings.
Remote monostatic detection of radioactive material by laser-induced breakdown
Authors: Isaacs Joshua , Miao Chenlong , Sprangle Phillip
Published: March 2016

This paper analyzes and evaluates a concept for remotely detecting the presence of radioactivity using electromagnetic signatures. The detection concept is based on the use of laser beams and the resulting electromagnetic signatures near the radioactive material. Free electrons, generated from ionizing radiation associated with the radioactive material, cascade down to low energies and attach to molecular oxygen. The resulting ion density depends on the level of radioactivity and can be readily photo-ionized by a low-intensity laser beam. This process provides a controllable source of seed electrons for the further collisional ionization (breakdown) of the air using a high-power, focused, CO2 laser pulse. When the air breakdown process saturates, the ionizing CO2 radiation reflects off the plasma region and can be detected. The time required for this to occur is a function of the level of radioactivity. This monostatic detection arrangement has the advantage that both the photo-ionizing and avalanche laser beams and the detector can be co-located.
Optical cell tracking analysis using a straight-forward approach to minimize processing time for high frame rate data
Authors: Seeto Wen Jun , Lipke Elizabeth Ann
Published: March 2016

Tracking of rolling cells via in vitro experiment is now commonly performed using customized computer programs. In most cases, two critical challenges continue to limit analysis of cell rolling data: long computation times due to the complexity of tracking algorithms and difficulty in accurately correlating a given cell with itself from one frame to the next, which is typically due to errors caused by cells that either come close in proximity to each other or come in contact with each other. In this paper, we have developed a sophisticated, yet simple and highly effective, rolling cell tracking system to address these two critical problems. This optical cell tracking analysis (OCTA) system first employs ImageJ for cell identification in each frame of a cell rolling video. A custom MATLAB code was written to use the geometric and positional information of all cells as the primary parameters for matching each individual cell with itself between consecutive frames and to avoid errors when tracking cells that come within close proximity to one another. Once the cells are matched, rolling velocity can be obtained for further analysis. The use of ImageJ for cell identification eliminates the need for high level MATLAB image processing knowledge. As a result, only fundamental MATLAB syntax is necessary for cell matching. OCTA has been implemented in the tracking of endothelial colony forming cell (ECFC) rolling under shear. The processing time needed to obtain tracked cell data from a 2 min ECFC rolling video recorded at 70 frames per second with a total of over 8000 frames is less than 6 min using a computer with an Intel® Core™ i7 CPU 2.80 GHz (8 CPUs). This cell tracking system benefits cell rolling analysis by substantially reducing the time required for post-acquisition data processing of high frame rate video recordings and preventing tracking errors when individual cells come in close proximity to one another.
Quantum dynamics of electronic transitions with Gauss-Hermite wave packets
Authors: Borrelli Raffaele , Peluso Andrea
Published: March 2016

A new methodology based on the superposition of time-dependent Gauss-Hermite wave packets is developed to describe the wave function of a system in which several interacting electronic states are coupled to a bath of harmonic oscillators. The equations of motion for the wave function parameters are obtained by employing the Dirac-Frenkel time-dependent variational principle. The methodology is applied to study the quantum dynamical behaviour of model systems with two interacting electronic states characterized by a relatively large reorganization energy and a range of energy biases. The favourable scaling properties make it a promising tool for the study of the dynamics of chemico-physical processes in molecular systems.
Highly periodic laser-induced nanostructures on thin Ti and Cu foils for potential application in laser ion acceleration
Authors: Das Susanta Kumar , Andreev Alexander , Messaoudi Hamza , Braenzel Julia , Schnuerer Matthias , Grunwald Ruediger
Published: March 2016

The feasibility of femtosecond laser-induced periodic nanostructures on thin Ti and Cu foils (thickness down to 1 μm) is demonstrated. At pulse durations of 120 fs and a wavelength of 400 nm, periods of 61 nm to 320 nm were obtained. Particle-in-cell simulations of laser ion acceleration processes with such nanostructured targets indicate their potential for high energy particle physics applications. In particular, a measurable enhancement of the proton cut-off energy and a significant enhancement of the number of accelerated particles compared to non- or weakly structured targets of same thickness and material are expected.
Investigating vibrational relaxation in cyanide-bridged transition metal mixed-valence complexes using two-dimensional infrared and infrared pump-probe spectroscopies
Authors: Slenkamp Karla M. , Lynch Michael S. , Brookes Jennifer F. , Bannan Caitlin C. , Daifuku Stephanie L. , Khalil Munira
Published: March 2016

Using polarization-selective two-dimensional infrared (2D IR) and infrared pump-probe spectroscopies, we study vibrational relaxation of the four cyanide stretching (νCN) vibrations found in [(NH3)5RuIIINCFeII(CN)5]− (FeRu) dissolved in D2O or formamide and [(NC)5FeIICNPtIV(NH3)4NCFeII(CN)5]4− (FePtFe) dissolved in D2O. These cyanide-bridged transition metal complexes serve as models for understanding the role high frequency vibrational modes play in metal-to-metal charge transfers over a bridging ligand. However, there is currently little information about vibrational relaxation and dephasing dynamics of the anharmonically coupled νCN modes in the electronic ground state of these complexes. IR pump-probe experiments reveal that the vibrational lifetimes of the νCN modes are ∼2 times faster when FeRu is dissolved in D2O versus formamide. They also reveal that the vibrational lifetimes of the νCN modes of FePtFe in D2O are almost four times as long as for FeRu in D2O. Combined with mode-specific relaxation dynamics measured from the 2D IR experiments, the IR pump-probe experiments also reveal that intramolecular vibrational relaxation is occurring in all three systems on ∼1 ps timescale. Center line slope dynamics, which have been shown to be a measure of the frequency-frequency correlation function, reveal that the radial, axial, and trans νCN modes exhibit a ∼3 ps timescale for frequency fluctuations. This timescale is attributed to the forming and breaking of hydrogen bonds between each mode and the solvent. The results presented here along with our previous work on FeRu and FePtFe reveal a picture of coupled anharmonic νCN modes where the spectral diffusion and vibrational relaxation dynamics depend on the spatial localization of the mode on the molecular complex and its specific interaction with the solvent.
Enhancing the electron lifetime and diffusion coefficient in dye-sensitized solar cells by patterning the layer of TiO2 nanoparticles
Authors: Sajedi Alvar Mohammad , Javadi Mohammad , Abdi Yaser , Arzi Ezatollah
Published: March 2016

In order to fulfill fast electron transport and low recombination rate in dye-sensitized solar cells, we propose to utilize a micro-patterned anode based on TiO2 nanoparticles. The micro-structures of the mesoporous TiO2 films were patterned by Si molds (microimprint technique). A series of measurements including the time of flight, open circuit voltage decay, and charge extraction is carried out to investigate the electron transport in these structures. Our measurement confirms the fast electron transport and high electron lifetime in the micro-patterned structures, which is in agreement with the previously reported simulations. The results have shown that for columnar 20 × 20 μm2 micro-structures, the electron diffusion coefficient is increased by 60% from 3.9 × 10−5 cm2/s to 6.3 × 10−5 cm2/s. In addition, the electron lifetime has considerably (about one order of magnitude) increased in the cells based on TiO2 micro-structures. These enhancements in the electron transport have significantly improved the power conversion efficiency of dye-sensitized solar cells, which is increased by 69% from 5.16% to 8.73%. The results are explained in terms of directional diffusion and extra trap states in the micro-structures of porous TiO2 films.
Development of three-dimensional integrated microchannel-electrode system to understand the particles' movement with electrokinetics
Authors: Yao J. , Obara H. , Sapkota A. , Takei M.
Published: March 2016

An optical transparent 3-D Integrated Microchannel-Electrode System (3-DIMES) has been developed to understand the particles' movement with electrokinetics in the microchannel. In this system, 40 multilayered electrodes are embedded at the 2 opposite sides along the 5 square cross-sections of the microchannel by using Micro Electro-Mechanical Systems technology in order to achieve the optical transparency at the other 2 opposite sides. The concept of the 3-DIMES is that the particles are driven by electrokinetic forces which are dielectrophoretic force, thermal buoyancy, electrothermal force, and electroosmotic force in a three-dimensional scope by selecting the excitation multilayered electrodes. As a first step to understand the particles' movement driven by electrokinetic forces in high conductive fluid (phosphate buffer saline (PBS)) with the 3-DIMES, the velocities of particles' movement with one pair of the electrodes are measured three dimensionally by Particle Image Velocimetry technique in PBS; meanwhile, low conductive fluid (deionized water) is used as a reference. Then, the particles' movement driven by the electrokinetic forces is discussed theoretically to estimate dominant forces exerting on the particles. Finally, from the theoretical estimation, the particles' movement mainly results from the dominant forces which are thermal buoyancy and electrothermal force, while the velocity vortex formed at the 2 edges of the electrodes is because of the electroosmotic force. The conclusions suggest that the 3-DIMES with PBS as high conductive fluid helps to understand the three-dimensional advantageous flow structures for cell manipulation in biomedical applications.
Broadband wide-angle absorption enhancement due to mode conversion in cold unmagnetized plasmas with periodic density variations
Authors: Yu Dae Jung , Kim Kihong
Published: March 2016

We study theoretically the mode conversion and the associated resonant absorption of p-polarized electromagnetic waves into longitudinal plasma oscillations in cold, unmagnetized and stratified plasmas with periodic spatial density variations. We consider sinusoidal density configurations for which the frequency band where mode conversion occurs is well included within a transmission band of the one-dimensional plasma photonic crystal. We calculate the mode conversion coefficient, which measures the fraction of the electromagnetic wave energy absorbed into the plasma, and the spatial distribution of the magnetic field intensity for various values of the wave frequency and the incident angle using the invariant imbedding theory of mode conversion. We find that the absorption is greatly enhanced over a wide range of frequency and incident angle due to the interplay between the mode conversion and the photonic band structure. The enhancement occurs because for frequencies within a transmission band, the wave reflection is strongly suppressed and the waves penetrate more deeply into the inhomogeneous region, thereby increasing the possibility for them to reach many resonance points where the dielectric permittivity vanishes.
Decomposition of the different contributions to permittivity, losses, and tunability in BaSrTiO3 thin films using the hyperbolic law
Authors: Nadaud Kevin , Borderon Caroline , Renoud Raphaël , Gundel Hartmut W.
Published: March 2016

In this paper, the different contributions to the permittivity of a 1% manganese-doped BaSrTiO3 thin film are presented as a function of the applied DC field. The hyperbolic law has been used to discern the lattice, domain wall vibration, and pinning/unpinning contributions. This decomposition permits us to study the weight of the respective contribution in the total permittivity, the losses, and the tunability. By determining the figure of merit (FoM) of each contribution, the ratio between tunability and losses, it is possible to identify the phenomenon which should be limited or enhanced in order to optimize the material's dielectric properties. It is shown that the tunability of the domain wall contribution (approximately 80%) is very important compared to the lattice contribution (41%), the associated dissipation factor, however, is also much larger (0.2 instead of 0.014). Even if the domain wall contribution has been shown to be weak in the investigated thin film (less than 3% in permittivity and tunability), the weight of the losses is not negligible (around 18%). Hence, the domain contribution has to be limited in order to conserve a high FoM for the material. Moreover, it is shown that the AC field used for the material's characterization is important because it governs the weight of the domain wall losses and thus the FoM.
Purely electrical detection of a skyrmion in constricted geometry
Authors: Hamamoto Keita , Ezawa Motohiko , Nagaosa Naoto
Published: March 2016

How to detect the skyrmion position is a crucial problem in future skyrmionics since it corresponds to the reading process of information. We propose a method to detect the skyrmion position purely electrically by measuring the Hall conductance in a constricted geometry. The Hall conductance becomes maximum when a skyrmion is at the lead position. It is possible to detect the skyrmion position even at room temperature. We find an optimized width of the sample determined by the skyrmion radius. We also investigate the effects of elastic and inelastic scatterings, and finite temperature. Our results will be a basis of future skyrmion electronics.
Mantle cloaking for co-site radio-frequency antennas
Authors: Monti Alessio , Soric Jason , Barbuto Mirko , Ramaccia Davide , Vellucci Stefano , Trotta Fabrizio , Alù Andrea , Toscano Alessandro , Bilotti Filiberto
Published: March 2016

We show that properly designed mantle cloaks, consisting of patterned metallic sheets placed around cylindrical monopoles, allow tightly packing the same antennas together in a highly dense telecommunication platform. Our experimental demonstration is applied to the relevant example of two cylindrical monopole radiators operating for 3G and 4G mobile communications. The two antennas are placed in close proximity, separated by 1/10 of the shorter operational wavelength, and, after cloaking, are shown to remarkably operate as if isolated in free-space. This result paves the way to unprecedented co-siting strategies for multiple antennas handling different services and installed in overcrowded platforms, such as communication towers, satellite payloads, aircrafts, or ship trees. More broadly, this work presents a significant application of cloaking technology to improve the efficiency of modern communication systems.
The impact of ultra-thin titania interlayers on open circuit voltage and carrier lifetime in thin film solar cells
Authors: Moerman David , Kim Hyungchul , Colbert Adam E. , Graham Samuel , Ginger David S.
Published: March 2016

We study the effects of modifying indium tin oxide electrodes with ultrathin titania (TiO2) layers grown via plasma-enhanced atomic layer deposition (PE-ALD). We find an optimal thickness of PE-ALD-grown titania by tracking performance, which initially increases, peaks, and eventually decreases with increasing TiO2 thickness. We use scanning Kelvin probe microscopy (SKPM) to measure both the local work function and its distribution as a function of TiO2 thickness. We find that the variance in contact potential difference across the surface of the film is related to either the amorphous or anatase TiO2 form. Finally, we use local SKPM recombination rate experiments, supported by bulk transient photovoltage and charge extraction measurements. We show that the optimum TiO2 thickness is the one for which the carrier lifetime is the longest and the charge carrier density is the highest, when the TiO2 is amorphous, in agreement with the device measurements.
Microfluidic cell fragmentation for mechanical phenotyping of cancer cells
Authors: Kamyabi Nabiollah , Vanapalli Siva A.
Published: March 2016

Circulating tumor cells (CTCs) shed from the primary tumor undergo significant fragmentation in the microvasculature, and very few escape to instigate metastases. Inspired by this in vivo behavior of CTCs, we report a microfluidic method to phenotype cancer cells based on their ability to arrest and fragment at a micropillar-based bifurcation. We find that in addition to cancer cell size, mechanical properties determine fragmentability. We observe that highly metastatic prostate cancer cells are more resistant to fragmentation than weakly metastatic cells, providing the first indication that metastatic CTCs can escape rupture and potentially initiate secondary tumors. Our method may thus be useful in identifying phenotypes that succumb to or escape mechanical trauma in microcirculation.
Evolution of an elliptic vortex ring in a viscous fluid
Authors: Cheng M. , Lou J. , Lim T. T.
Published: March 2016

The evolution of a viscous elliptic vortex ring in an initially quiescent fluid or a linear shear flow is numerically simulated using a lattice Boltzmann method. A wide range of parameters are considered, namely, aspect ratios (AR) (1 ≤ AR ≤ 8), core radius to ring radius ratios (σ0) (0.1 ≤ σ0 ≤ 0.3), Reynolds number (Re) (500 ≤ Re ≤ 3000), and shear rate (K) (0 ≤ K ≤ 0.12). The study aims to fill the gap in the current knowledge of the dynamics of an elliptic vortex ring in a viscous fluid and also to address the issue of whether an elliptic ring undergoes vortex stretching and compression during axis-switching. In a quiescent fluid, results show that for fixed Re and σ0, there exists a critical aspect ratio (ARc), below which an elliptic ring undergoes oscillatory deformation with the period that increases with increasing AR. Above ARc, the vortex ring breaks up into two or three sub-rings after the first half-cycle of oscillation. While higher Reynolds number enhances vortex ring breakup, larger core size has the opposite effect. Contrary to an inviscid theory, an elliptic ring does undergo vortex stretching and compression during oscillatory deformation. In the presence of a linear shear flow, the vortex ring undergoes not only oscillatory deformation and stretching but also tilting as it propagates downstream. The tilting angle increases with the shear rate K and is responsible for inducing a “tail” that consists of a counter-rotating vortex pair (CVP) near the upstream end of the initial major axis after the first half-cycle of oscillation. For a high shear rate, the CVP wraps around the ring and transforms its topological structure from a simple elliptic geometry to a complicated structure that eventually leads to the generation of turbulence.
Landau-Zener-Stückelberg-Majorana interference in a 3D transmon driven by a chirped microwave
Authors: Gong Ming , Zhou Yu , Lan Dong , Fan Yunyi , Pan Jiazheng , Yu Haifeng , Chen Jian , Sun Guozhu , Yu Yang , Han Siyuan , Wu Peiheng
Published: March 2016

By driving a 3D transmon with microwave fields, we generate an effective avoided energy-level crossing. Then we chirp microwave frequency, which is equivalent to driving the system through the avoided energy-level crossing by sweeping the avoided crossing. A double-passage chirp produces Landau-Zener-Stückelberg-Majorana (LZSM) interference that agree well with the numerical results, especially with the initial state being an eigen-energy state in the center of an avoided level crossing. A time-resolved state tomography measurement is performed in the evolution of LZSM interference, showing an experimental evidence for the dynamical evolution of quantum state. Our method is fully applicable to other quantum systems that contain no intrinsic avoided level crossing, providing an alternative approach for quantum control and quantum simulation.
Temperature dependence of FMR and magnetization in nanocrystalline zinc ferrite thin films
Authors: Sahu B. N. , Doshi Akash S. , Prabhu R. , Venkataramani N. , Prasad Shiva , Krishnan R.
Published: March 2016

Single phase nano-crystalline zinc ferrite thin films were deposited by RF-magnetron sputtering on quartz substrate at room temperature (RT) in pure Argon environment and annealed (in air) at different temperatures. Temperature dependence of magnetization was studied on these films using both VSM and by observing FMR (in X band). Value of exchange stiffness constant (D) was obtained by fitting Bloch’s law to the low temperature magnetization data. The value of D decreased monotonously with the annealing temperature (TA) of the samples. A film annealed at TA = 523 K, exhibited the highest magnetization value. The FMR line width of the films decreased with increase in measurement temperature. At RT (∼293 K), the lowest value of line width (ΔH) was 15 kA/m and 13 kA/m in parallel and perpendicular configuration respectively for the sample annealed at TA = 623 K.
Dielectric constant and charging energy in array of touching nanocrystals
Authors: Reich K. V. , Shklovskii B. I.
Published: March 2016

We calculate the effective macroscopic dielectric constant εa of a periodic array of spherical nanocrystals (NCs) with dielectric constant ε immersed in the medium with dielectric constant εm ≪ ε. For an array of NCs with the diameter d and the distance D between their centers, which are separated by the small distance s = D – d ≪ d or touch each other by small facets with radius ρ ≪ d what is equivalent to s < 0, |s|≪d we derive two analytical asymptotics of the function εa(s) in the limit ε/εm ≫ 1. Using the scaling hypothesis, we interpolate between them near s = 0 to obtain new approximated function εa(s) for ε/εm ≫ 1. It agrees with existing numerical calculations for ε/εm = 30, while the standard mean-field Maxwell-Garnett and Bruggeman approximations fail to describe percolation-like behavior of εa(s) near s = 0. We also show that in this case the charging energy Ec of a single NC in an array of touching NCs has a non-trivial relationship to εa, namely, Ec = αe2/εad, where α varies from 1.59 to 1.95 depending on the studied three-dimensional lattices. Our approximation for εa(s) can be used instead of mean field Maxwell-Garnett and Bruggeman approximations to describe percolation like transitions near s = 0 for other material characteristics of NC arrays, such as conductivity.
Enhancing the thermal conductivity of ethylene-vinyl acetate (EVA) in a photovoltaic thermal collector
Authors: Allan J. , Pinder H. , Dehouche Z.
Published: March 2016

Samples of Ethylene-Vinyl Acetate (EVA) were doped with particles of Boron Nitride (BN) in concentrations ranging from 0-60% w/w. Thermal conductivity was measured using a Differential Scanning Calorimetery (DSC) technique. The thermal conductivity of parent EVA was increased from 0.24W/m ⋅ K to 0.80W/m ⋅ K for the 60% w/w sample. Two PV laminates were made; one using the parent EVA the other using EVA doped with 50% BN. When exposed to a one directional heat flux the doped laminate was, on average, 6% cooler than the standard laminate. A finite difference model had good agreement with experimental results and showed that the use of 60% BN composite achieved a PV performance increase of 0.3% compared to the standard laminate.
Alkali metal ion storage properties of sulphur and phosphorous molecules encapsulated in nanometer size carbon cylindrical pores
Authors: Ishii Yosuke , Sakamoto Yuki , Song Hayong , Tashiro Kosuke , Nishiwaki Yoshiki , Al-zubaidi Ayar , Kawasaki Shinji
Published: March 2016

We investigated the physical and chemical stabilities of sulfur and phosphorus molecules encapsulated in a mesoporous carbon (MPC) and two kinds of single-walled carbon nanotubes (SWCNTs) having different cylindrical pore diameters. The sublimation temperatures of sulfur molecules encapsulated in MPC and the two kinds of SWCNTs were measured by thermo-gravimetric measurements. It was found that the sublimation temperature of sulfur molecules encapsulated in SWCNTs having mean tube diameter of 1.5 nm is much higher than any other molecules encapsulated in larger pores. It was also found that the capacity fading of lithium-sulfur battery can be diminished by encapsulation of sulfur molecules in SWCNTs. We also investigated the electrochemical properties of phosphorus molecules encapsulated in SWCNTs (P@SWCNTs). It was shown that P@SWCNT can adsorb and desorb both Li and Na ions reversibly.
Fate of N in soil amended with 15N-labelled residues of winter cereals combined with an organic N fertiliser
Authors: Gioacchini Paola , Montecchio Daniela , Gnudi Emanuela , Terzi Valeria , Stanca Antonio Michele , Ciavatta Claudio , Marzadori Claudio
Published: March 2016

In organic farming winter cereals, as cover crops, provide nutrients, when they return to soil as crop residues. The fate of N deriving from two decomposing 15N-labelled winter cereals, with or without the supply of an organic N fertiliser, was studied in a field experiment. The stabilisation of residues N in soil aggregates and the portion lost from the system were also evaluated. Barley or triticale residues were incubated alone or with hydrolysed leather (L) in mesocosms over one year. The residues derived N was measured in soil and in soil aggregate size fractions >250 μm (macroaggregates, macro); 53–250 μm (microaggregates, micro); <53 μm (silt and clay, s+c) obtained by wet sieving. Barley degradation (77% of the initial amount) was faster than triticale degradation (55%). The L slowed down the barley degradation (72%) and speeded that of triticale (64%). Greater amount of residues N was in macro and micro than in s+c. The presence of L reduced the residues N stabilised in the finest fractions. The losses of barley N were reduced by the L addition, those from triticale were increased. The fate of residues N was affected by the L application that influenced the residues mineralisation, the stabilisation and the losses of their derived N.