bluuebunny/crossref_metadata_2025 huggingface dataset:
Balanced π–π interactions directing the self-assembly of indolocarbazole-based low molecular mass organogelators
Authors: Gong Peng , Xue Pengchong , Qian Chong , Zhang Zhenqi , Lu Ran
Published: June 2014

New indolocarbazole-based organogelators emitting strong blue light have been synthesized.
Desilylative activation of TMSCN in chemoselective Strecker–Ugi type reaction: functional fused imidazoles as building blocks as an entry route to annulated purines
Authors: Guchhait Sankar K. , Chaudhary Vikas
Published: June 2014

Nucleophilic activation of TMSCN as an isocyanide equivalent by DABCO–THF in the Strecker–Ugi reaction facilitates the synthesis of functional imidazoles which, as building blocks, afford access to C8–N9 annulated purines.
Catalytic synthesis of polyethylene-block-polynorbornene copolymers using a living polymerization nickel catalyst
Authors: Gao Haiyang , Liu Yong , Li Guiliang , Xiao Zefan , Liang Guodong , Wu Qing
Published: June 2014

Well-defined polyethylene-block-polynorbornene copolymers were synthesized using an amine–imine nickel catalyst.
Anion exchange membranes by bromination of benzylmethyl-containing poly(arylene ether)s for alkaline membrane fuel cells
Authors: Li Xiuhua , Cheng Shanshan , Wang Liuchan , Long Qiang , Tao Jinxiong , Nie Guanghui , Liao Shijun
Published: June 2014

Fast and safe fabrication of anion exchange membranes started with the bromination of poly(arylene ether)s containing tetramethyl triphenyl methane moieties.
DFT studies on the mechanism of veratryl alcohol oxidation catalyzed by Cu–phen complexes
Authors: Ma Lisha , Zhang Qiancheng , Cheng Lin , Wu Zhijian , Yang Jucai
Published: June 2014

Density functional theory (DFT) calculations have been performed to investigate the catalytic mechanism for the oxidation of veratryl alcohol to veratraldehyde by Cu–phen catalyst. In this work, the most favorable mechanism has been predicted and we hope the obtained results could provide useful insights for the reaction process.
Enzyme-catalysed oxidation of 1,2-disulfides to yield chiral thiosulfinate, sulfoxide and cis-dihydrodiol metabolites
Authors: Boyd Derek R. , Sharma Narain D. , Shepherd Steven D. , Allenmark Stig G. , Allen Christopher C. R.
Published: June 2014

Oxidative biotransformations of 1,2-disulfides using bacterial whole cells and pure enzymes yielded an unexpectedly wide range of products including thiolactones and chiral thiosulfinate, sulfoxide,cis-diol and metabolites.
Olefin separation via charge transfer and dipole formation at the silver nanoparticle–tetracyanoquinoid interface
Authors: Chae Il Seok , Kang Sang Wook , Kang Yong Soo
Published: June 2014

Charge transfer and dipole formation at silver nanoparticle–tetracyanoquinoid takes place in the solid-state membrane, forming an unprecedented, highly olefin permselective facilitated transport membrane with a mixed gas selectivity of over 100 for a propylene–propane mixture. This provides a potential alternative to the highly energy-intensive cryogenic distillation process for olefin/paraffin separation.
A conceptual DFT study of the hydrogen trapping efficiency in metal functionalized BN system
Authors: Samolia Madhu , Kumar T. J. Dhilip
Published: June 2014

We investigate the hydrogen trapping efficiency of various metals functionalized on BN systems for potential hydrogen storage applications using conceptual DFT’s stability and reactivity descriptors.
Direct electrochemistry of glucose oxidase immobilized on ZrO2nanoparticles-decorated reduced graphene oxide sheets for a glucose biosensor
Authors: Vilian A. T. Ezhil , Chen Shen-Ming , Ali M. Ajmal , Al-Hemaid Fahad M. A.
Published: June 2014

Schematic representation of the preparation procedure of GOx–PLL/RGO–ZrO2composite.
Synthesis, characterization and antimicrobial studies of some new trifluoromethyl quinoline-3-carbohydrazide and 1,3,4-oxadiazoles
Authors: Garudachari B. , Isloor Arun M. , Satyanaraya M. N. , Ananda K. , Fun Hoong-Kun
Published: June 2014

7-(Trifluoromethyl)-4-hydroxy substituted quinolinecarbazide derivatives (6a–eand7a–g) andN-alkyl-3-(5-phenyl-1,3,4-oxadiazol-2-yl)-7-(trifluoromethyl) quinolin-4-amine (9a–f) were synthesized, characterized and screened for their antimicrobial activity.
Energy harvesting from humidity changes with a flexible coaxial electrode solid-state cell
Authors: Smithyman Jesse , Liang Zhiyong
Published: June 2014

A measurable Gibbs free energy is obtained in a coaxial electrode cell from concentration gradients induced by changes in the relative humidity.
Structural response of an ordered block copolymer melt to uniaxial extensional flow
Authors: Mao Ruinan , McCready Erica M. , Burghardt Wesley R.
Published: June 2014

Two-dimensional SAXS patterns reveal deformation and re-orientation of microdomains in a hexagonally ordered block copolymer melt subjected to uniaxial extensional flow.
Elasticity, viscosity, and orientational fluctuations of a lyotropic chromonic nematic liquid crystal disodium cromoglycate
Authors: Zhou Shuang , Neupane Krishna , Nastishin Yuriy A. , Baldwin Alan R. , Shiyanovskii Sergij V. , Lavrentovich Oleg D. , Sprunt Samuel
Published: June 2014

Using dynamic light scattering, we study orientational fluctuation modes in the nematic phase of a self-assembled lyotropic chromonic liquid crystal disodium cromoglycate and measure the Frank elastic moduli and viscosity coefficients.
Thermoelectric properties of Mn-doped Mg–Sb single crystals
Authors: Kim Soohyun , Kim Chungman , Hong Yang-Ki , Onimaru Takahiro , Suekuni Koichiro , Takabatake Toshiro , Jung Myung-Hwa
Published: June 2014

The thermoelectric properties of Mg–Sb single crystals, which are compared with their polycrystalline counterparts, are enhanced by introducing Mn.
Gas sensing properties of Cu2O and its particle size and morphology-dependent gas-detection sensitivity
Authors: Wan Xuejuan , Wang Jilei , Zhu Lianfeng , Tang Jiaoning
Published: June 2014

Particle size and morphology-dependent gas-detection sensitivity were studied, and the results indicated that the particle stacking mode is a key factor influencing gas sensing performance.
Co-doped NiO nanoflake array films with enhanced electrochromic properties
Authors: Zhang Jia-heng , Cai Guo-fa , Zhou Ding , Tang Hong , Wang Xiu-li , Gu Chang-dong , Tu Jiang-ping
Published: June 2014

Co-doped NiO nanoflake array films, which exhibit improved electrochromic performance with antireflective ability, are fabricated by chemical bath deposition.
Cardiac-targeting magnetic lipoplex delivery of SH-IGF1R plasmid attenuate norepinephrine-induced cardiac hypertrophy in murine heart
Authors: Xu Yiping , Li Xuebiao , Kong Minjian , Jiang Daming , Dong Aiqiang , Shen Zhonghua , Duan Qunjun
Published: June 2014

Recent studies have demonstrated a number of molecular mechanisms contributing to the initiation of cardiac hypertrophy response to pressure overload. IGF1R (insulin-like growth factor-1 receptor), an important oncogene, is overexpressed in hypertrophic heart and mediates the hypertrophic pathology process. In this study, we applied with liposomal magnetofection that potentiated gene transfection by applying an external magnetic field to enhance its transfection efficiency. Liposomal magnetofection provided high efficiency in transgene expression in vivo. In vivo, IGF1R-specific-shRNA (small-hairpin RNA) by magnetofection inhibited IGF1R protein expression by 72.2±6.8, 80.7±9.6 and 84.5±5.6%, at 24, 48 and 72 h, respectively, after pGFPshIGF1R injection, indicating that liposomal magnetofection is a promising method that allows the targeting of gene therapy for heart failure. Furthermore, we found that the treated animals (liposomal magnetofection with shIGF1R) showed reduced septal and posterior wall thickness, reduced HW:BWs (heart weight-to-body weights) compared with controls. Moreover, we also found that liposomal magnetofection-based shIGF1R transfection decreased the expression level of p-ERK (phosphorylated extracellular-signal-regulated kinase)1/2, p-AKT1 (phosphorylated protein kinase B1) compared with untreated hearts. These results suggested that liposomal magnetofection-mediated IGF1R-specific-shRNA may be a promising method, and suppression the IGF1R expression inhibited norepinephrine-induced cardiac hypertrophic process via inhibiting PI3K (phosphoinositide 3-kinase)/AKT pathway.
Optimal power allocation and relay selection for multiple code division multiple access peer‐to‐peer communication
Authors: Lashkari Banafsheh , Biguesh Mehrzad , Gazor Saeed
Published: June 2014

The authors consider a half‐duplex asynchronous code division multiple access cooperative network with N source–destination (SD) pairs and a number of relay nodes where the nodes of all pairs have to exchange data in two hops via assistance of one of the available relays. In this study, they minimise the total transmit power and derive the closed‐form solution for choosing the best relay, the best relay gain and the transmit powers of all sources where some predefined signal‐to‐interference plus noise‐ratios (SINRs) are guaranteed. Interestingly, the feasibility condition of the problem depends only on the required SINRs, the number of SD pairs and the maximum cross‐correlation of users’ codes. They suggest two control procedures for admitting or dropping of users to the network to satisfy the feasibility condition. For a reciprocal environment, the best relay and its gain are proved to remain unchanged for reversing the communication directions. In addition, the authors’ power control algorithm can be directly applied to the case of two‐hop two‐way relaying. Computer simulations are used to demonstrate the system performance.
Osteomyelitis of the Temporal Bone: Terminology, Diagnosis, and Management
Authors: Prasad Sampath Chandra , Prasad Kishore Chandra , Kumar Abhijit , Thada Nikhil Dinaker , Rao Pallavi , Chalasani Satyanarayana
Published: June 2014

Objectives To review the terminology, clinical features, and management of temporal bone osteomyelitis.

Design and Setting Prospective study in a tertiary care center from 2001 to 2008.

Participants Twenty patients visiting the outpatient department diagnosed with osteomyelitis of the temporal bone.

Main Outcome Measures The age, sex, clinical features, cultured organisms, surgical interventions, and classification were analyzed.

Results Of the 20 cases, 2 (10%) were diagnosed as acute otitis media. Eighteen (90%) had chronic otitis media. Nineteen (95%) were classified as medial temporal bone osteomyelitis and one (5%) as lateral temporal osteomyelitis. The most common clinical features were ear discharge (100%), pain (83%), and granulations (100%). Facial nerve palsy was seen in seven cases (35%) and parotid involvement in one case. Ten patients (56%) had diabetes mellitus. The organisms isolated were Pseudomonas aeruginosa (80%) and Staphylococcus aureus (13.33%). Histopathology revealed chronic inflammation in 20 patients (100%) and osteomyelitic bony changes in 14 (70%). Surgical debridement was the most preferred modality of treatment (87%).

Conclusion A new classification of temporal bone osteomyelitis has been proposed. Bacterial cultures must be performed in all patients. Antibiotic therapy is the treatment of choice. Surgical intervention is necessary in the presence of severe pain, complications, refractory cases, or the presence of bony sequestra on radiology.
A different view of structure-making and structure-breaking in alkali halide aqueous solutions through x-ray absorption spectroscopy
Authors: Waluyo Iradwikanari , Nordlund Dennis , Bergmann Uwe , Schlesinger Daniel , Pettersson Lars G. M. , Nilsson Anders
Published: June 2014

X-ray absorption spectroscopy measured in transmission mode was used to study the effect of alkali and halide ions on the hydrogen-bonding (H-bonding) network of water. Cl− and Br− are shown to have insignificant effect on the structure of water while I− locally weakens the H-bonding, as indicated by a sharp increase of the main-edge feature in the x-ray absorption spectra. All alkali cations act as structure-breakers in water, weakening the H-bonding network. The spectral changes are similar to spectra of high density ices where the 2nd shell has collapsed due to a break-down of the tetrahedral structures, although here, around the ions, the breakdown of the local tetrahedrality is rather due to non-directional H-bonding to the larger anions. In addition, results from temperature-dependent x-ray Raman scattering measurements of NaCl solution confirm the H-bond breaking effect of Na+ and the effect on the liquid as similar to an increase in temperature.
A flexible skin piloerection monitoring sensor
Authors: Kim Jaemin , Seo Dae Geon , Cho Young-Ho
Published: June 2014

We have designed, fabricated, and tested a capacitive-type flexible micro sensor for measurement of the human skin piloerection arisen from sudden emotional and environmental change. The present skin piloerection monitoring methods are limited in objective and quantitative measurement by physical disturbance stimulation to the skin due to bulky size and heavy weight of measuring devices. The proposed flexible skin piloerection monitoring sensor is composed of 3 × 3 spiral coplanar capacitor array using conductive polymer for having high capacitive density and thin enough thickness to be attached to human skin. The performance of the skin piloerection monitoring sensor is characterized using the artificial bump, representing human skin goosebump; thus, resulting in the sensitivity of −0.00252%/μm and the nonlinearity of 25.9% for the artificial goosebump deformation in the range of 0–326 μm. We also verified successive human skin piloerection having 3.5 s duration on the subject's dorsal forearms, thus resulting in the capacitance change of −6.2 fF and −9.2 fF for the piloerection intensity of 145 μm and 194 μm, respectively. It is demonstrated experimentally that the proposed sensor is capable to measure the human skin piloerection objectively and quantitatively, thereby suggesting the quantitative evaluation method of the qualitative human emotional status for cognitive human-machine interfaces applications.
Subthreshold-swing physics of tunnel field-effect transistors
Authors: Cao Wei , Sarkar Deblina , Khatami Yasin , Kang Jiahao , Banerjee Kaustav
Published: June 2014

Band-to-band tunnel field-effect-transistors (TFETs) are considered a possible replacement for the conventional metal-oxide-semiconductor field-effect transistors due to their ability to achieve subthreshold swing (SS) below 60 mV/decade. This letter reports a comprehensive study of the SS of TFETs by examining the effects of electrostatics and material parameters of TFETs on their SS through a physics based analytical model. Based on the analysis, an intrinsic SS degradation effect in TFETs is uncovered. Meanwhile, it is also shown that designing a strong onset condition, quantified by an introduced concept - “onset strength”, for TFETs can effectively overcome this degradation at the onset stage, and thereby achieve ultra-sharp switching characteristics. The uncovered physics provides theoretical support to recent experimental results, and forward looking insight into more advanced TFET design.
Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry
Authors: Meusinger Carl , Berhanu Tesfaye A. , Erbland Joseph , Savarino Joel , Johnson Matthew S.
Published: June 2014

Post-depositional processes alter nitrate concentration and nitrate isotopic composition in the top layers of snow at sites with low snow accumulation rates, such as Dome C, Antarctica. Available nitrate ice core records can provide input for studying past atmospheres and climate if such processes are understood. It has been shown that photolysis of nitrate in the snowpack plays a major role in nitrate loss and that the photolysis products have a significant influence on the local troposphere as well as on other species in the snow. Reported quantum yields for the main reaction spans orders of magnitude – apparently a result of whether nitrate is located at the air-ice interface or in the ice matrix – constituting the largest uncertainty in models of snowpack NOx emissions. Here, a laboratory study is presented that uses snow from Dome C and minimizes effects of desorption and recombination by flushing the snow during irradiation with UV light. A selection of UV filters allowed examination of the effects of the 200 and 305 nm absorption bands of nitrate. Nitrate concentration and photon flux were measured in the snow. The quantum yield for loss of nitrate was observed to decrease from 0.44 to 0.003 within what corresponds to days of UV exposure in Antarctica. The superposition of photolysis in two photochemical domains of nitrate in snow is proposed: one of photolabile nitrate, and one of buried nitrate. The difference lies in the ability of reaction products to escape the snow crystal, versus undergoing secondary (recombination) chemistry. Modeled NOx emissions may increase significantly above measured values due to the observed quantum yield in this study. The apparent quantum yield in the 200 nm band was found to be ∼1%, much lower than reported for aqueous chemistry. A companion paper presents an analysis of the change in isotopic composition of snowpack nitrate based on the same samples as in this study.
The Weibel instability in a strongly coupled plasma
Authors: Mahdavi M. , Khanzadeh H.
Published: June 2014

In this paper, the growth rate of the Weibel instability is calculated for an energetic relativistic electron beam penetrated into a strongly coupled plasma, where the collision effects of background electron-ion scattering play an important role in equations. In order to calculate the growth rate of the Weibel instability, two different models of anisotropic distribution function are used. First, the distribution of the plasma and beam electrons considered as similar forms of bi-Maxwellian distribution. Second, the distribution functions of the plasma electrons and the beam electrons follows bi-Maxwellian and delta-like distributions, respectively. The obtained results show that the collision effect decreases the growth rate in two models. When the distribution function of electrons beam is in bi-Maxwellian form, the instability growth rate is greater than where the distribution function of beam electrons is in delta-like form, because, the anisotropic temperature for bi-Maxwellian distribution function in velocity space is greater than the delta-like distribution function.
A new Gaussian MCTDH program: Implementation and validation on the levels of the water and glycine molecules
Authors: Skouteris D. , Barone V.
Published: June 2014

We report the main features of a new general implementation of the Gaussian Multi-Configuration Time-Dependent Hartree model. The code allows effective computations of time-dependent phenomena, including calculation of vibronic spectra (in one or more electronic states), relative state populations, etc. Moreover, by expressing the Dirac-Frenkel variational principle in terms of an effective Hamiltonian, we are able to provide a new reliable estimate of the representation error. After validating the code on simple one-dimensional systems, we analyze the harmonic and anharmonic vibrational spectra of water and glycine showing that reliable and converged energy levels can be obtained with reasonable computing resources. The data obtained on water and glycine are compared with results of previous calculations using the vibrational second-order perturbation theory method. Additional features and perspectives are also shortly discussed.
Experimental investigations of argon spark gap recovery times by developing a high voltage double pulse generator
Authors: Reddy C. S. , Patel A. S. , Naresh P. , Sharma Archana , Mittal K. C.
Published: June 2014

The voltage recovery in a spark gap for repetitive switching has been a long research interest. A two-pulse technique is used to determine the voltage recovery times of gas spark gap switch with argon gas. First pulse is applied to the spark gap to over-volt the gap and initiate the breakdown and second pulse is used to determine the recovery voltage of the gap . A pulse transformer based double pulse generator capable of generating 40 kV peak pulses with rise time of 300 ns and 1.5 μs FWHM and with a delay of 10 μs–1 s was developed. A matrix transformer topology is used to get fast rise times by reducing LlCd product in the circuit. Recovery Experiments have been conducted for 2 mm, 3 mm, and 4 mm gap length with 0–2 bars pressure for argon gas. Electrodes of a sparkgap chamber are of rogowsky profile type, made up of stainless steel material, and thickness of 15 mm are used in the recovery study. The variation in the distance and pressure effects the recovery rate of the spark gap. An intermediate plateu is observed in the spark gap recovery curves. Recovery time decreases with increase in pressure and shorter gaps in length are recovering faster than longer gaps.
Adsorption and diffusion of colloidal Au nanoparticles at a liquid-vapor interface
Authors: Poddar Nitun N. , Amar Jacques G.
Published: June 2014

Motivated by recent drop-drying experiments of Au nanoparticle (NP) island self-assembly, we investigate the structure, diffusion, and binding of dodecanethiol-coated Au NPs adsorbed at the toluene-vapor interface using molecular dynamics (MD) simulations as well as analytical calculations. For a 6 nm core diameter NP our results indicate the existence of significant intermixing between the ligands and the solvent. As a result, the NP lies primarily below the interface with only a portion of the ligands sticking out, while the toluene-vapor interface is significantly higher in the region above the NP core than away from the NP. These results are consistent with a competition between the negative free energy of mixing of toluene and the dodecanethiol ligands, which tends to keep the NP below the interface, and the effects of surface tension which keeps the NP near the interface. Consistent with this result, we find that the coefficient for nanoparticle diffusion along the interface is close to the Stokes-Einstein prediction for three-dimensional bulk diffusion. An analysis of the ligand arrangement surrounding the NP also indicates that there is relatively little asymmetry in the ligand-coating. We then consider the effects of van der Waals interactions on the adsorption energy. In particular, we derive an analytical expression for the van der Waals interaction energy between a coated nanoparticle and the surrounding solvent along with a closed-form expression for the van der Waals corrections to the binding energy at the interface due to the long-range core-solvent interaction. Using these results along with the results of our MD simulations, we then estimate the van der Waals corrections to the adsorption energy for dodecanethiol-coated Au nanoparticles at the toluene-vapor interface as well as for decanethiol-coated nanoparticles at the water-vapor interface. In both cases, we find that the long-range core-solvent interaction may significantly reduce the binding energy. Based on these results, we conclude that in many cases, the core-solvent van der Waals interaction is likely to have a significant effect on the binding energy and interface position of Au NPs. Our results also indicate that the competition between the van der Waals interaction and the short-range attraction to the interface leads to the existence of well-defined activation barriers for nanoparticle adsorption from the solvent as well as for interfacial desorption.
Elucidating the effects of adsorbent flexibility on fluid adsorption using simple models and flat-histogram sampling methods
Authors: Shen Vincent K. , Siderius Daniel W.
Published: June 2014

Using flat-histogram Monte Carlo methods, we investigate the adsorptive behavior of the square-well fluid in two simple slit-pore-like models intended to capture fundamental characteristics of flexible adsorbent materials. Both models require as input thermodynamic information about the flexible adsorbent material itself. An important component of this work involves formulating the flexible pore models in the appropriate thermodynamic (statistical mechanical) ensembles, namely, the osmotic ensemble and a variant of the grand-canonical ensemble. Two-dimensional probability distributions, which are calculated using flat-histogram methods, provide the information necessary to determine adsorption thermodynamics. For example, we are able to determine precisely adsorption isotherms, (equilibrium) phase transition conditions, limits of stability, and free energies for a number of different flexible adsorbent materials, distinguishable as different inputs into the models. While the models used in this work are relatively simple from a geometric perspective, they yield non-trivial adsorptive behavior, including adsorption-desorption hysteresis solely due to material flexibility and so-called “breathing” of the adsorbent. The observed effects can in turn be tied to the inherent properties of the bare adsorbent. Some of the effects are expected on physical grounds while others arise from a subtle balance of thermodynamic and mechanical driving forces. In addition, the computational strategy presented here can be easily applied to more complex models for flexible adsorbents.
Lagrangian framework for systems composed of high-loss and lossless components
Authors: Figotin Alexander , Welters Aaron
Published: June 2014

Using a Lagrangian mechanics approach, we construct a framework to study the dissipative properties of systems composed of two components one of which is highly lossy and the other is lossless. We have shown in our previous work that for such a composite system the modes split into two distinct classes, high-loss and low-loss, according to their dissipative behavior. A principal result of this paper is that for any such dissipative Lagrangian system, with losses accounted by a Rayleigh dissipative function, a rather universal phenomenon occurs, namely, selective overdamping: The high-loss modes are all overdamped, i.e., non-oscillatory, as are an equal number of low-loss modes, but the rest of the low-loss modes remain oscillatory each with an extremely high quality factor that actually increases as the loss of the lossy component increases. We prove this result using a new time dynamical characterization of overdamping in terms of a virial theorem for dissipative systems and the breaking of an equipartition of energy.
Dean flow-coupled inertial focusing in curved channels
Authors: Ramachandraiah Harisha , Ardabili Sahar , Faridi Asim M. , Gantelius Jesper , Kowalewski Jacob M. , Mårtensson Gustaf , Russom Aman
Published: June 2014

Passive particle focusing based on inertial microfluidics was recently introduced as a high-throughput alternative to active focusing methods that require an external force field to manipulate particles. In inertial microfluidics, dominant inertial forces cause particles to move across streamlines and occupy equilibrium positions along the faces of walls in flows through straight micro channels. In this study, we systematically analyzed the addition of secondary Dean forces by introducing curvature and show how randomly distributed particles entering a simple u-shaped curved channel are focused to a fixed lateral position exiting the curvature. We found the lateral particle focusing position to be fixed and largely independent of radius of curvature and whether particles entering the curvature are pre-focused (at equilibrium) or randomly distributed. Unlike focusing in straight channels, where focusing typically is limited to channel cross-sections in the range of particle size to create single focusing point, we report here particle focusing in a large cross-section area (channel aspect ratio 1:10). Furthermore, we describe a simple u-shaped curved channel, with single inlet and four outlets, for filtration applications. We demonstrate continuous focusing and filtration of 10 μm particles (with >90% filtration efficiency) from a suspension mixture at throughputs several orders of magnitude higher than flow through straight channels (volume flow rate of 4.25 ml/min). Finally, as an example of high throughput cell processing application, white blood cells were continuously processed with a filtration efficiency of 78% with maintained high viability. We expect the study will aid in the fundamental understanding of flow through curved channels and open the door for the development of a whole set of bio-analytical applications.
A combined compensation method for the output voltage of an insulated core transformer power supply
Authors: Yang L. , Yang J. , Liu K. F. , Qin B. , Chen D. Z.
Published: June 2014

An insulated core transformer (ICT) power supply is an ideal high-voltage generator for irradiation accelerators with energy lower than 3 MeV. However, there is a significant problem that the structure of the segmented cores leads to an increase in the leakage flux and voltage differences between rectifier disks. A high level of consistency in the output of the disks helps to achieve a compact structure by improving the utilization of both the rectifier components and the insulation distances, and consequently increase the output voltage of the power supply. The output voltages of the disks which are far away from the primary coils need to be improved to reduce their inhomogeneity. In this study, by investigating and comparing the existing compensation methods, a new combined compensation method is proposed, which increases the turns on the secondary coils and employs parallel capacitors to improve the consistency of the disks, while covering the entire operating range of the power supply. This method turns out to be both feasible and effective during the development of an ICT power supply. The non-uniformity of the output voltages of the disks is less than 3.5% from no-load to full-load, and the power supply reaches an output specification of 350 kV/60 mA.
Design, performance, and grounding aspects of the International Thermonuclear Experimental Reactor ion cyclotron range of frequencies antenna
Authors: Durodié F. , Dumortier P. , Vrancken M. , Messiaen A. , Bamber R. , Hancock D. , Huygen S. , Lockley D. , Louche F. , Maggiora R. , Milanesio D. , Nightingale M. P. S. , Shannon M. , Tigwell P. , Van Schoor M. , Vervier M. , Wilson D. , Winkler K. ,   CYCLE Team
Published: June 2014

ITER's Ion Cyclotron Range of Frequencies (ICRF) system [Lamalle et al., Fusion Eng. Des. 88, 517–520 (2013)] comprises two antenna launchers designed by CYCLE (a consortium of European associations listed in the author affiliations above) on behalf of ITER Organisation (IO), each inserted as a Port Plug (PP) into one of ITER's Vacuum Vessel (VV) ports. Each launcher is an array of 4 toroidal by 6 poloidal RF current straps specified to couple up to 20 MW in total to the plasma in the frequency range of 40 to 55 MHz but limited to a maximum system voltage of 45 kV and limits on RF electric fields depending on their location and direction with respect to, respectively, the torus vacuum and the toroidal magnetic field. A crucial aspect of coupling ICRF power to plasmas is the knowledge of the plasma density profiles in the Scrape-Off Layer (SOL) and the location of the RF current straps with respect to the SOL. The launcher layout and details were optimized and its performance estimated for a worst case SOL provided by the IO. The paper summarizes the estimated performance obtained within the operational parameter space specified by IO. Aspects of the RF grounding of the whole antenna PP to the VV port and the effect of the voids between the PP and the Blanket Shielding Modules (BSM) surrounding the antenna front are discussed. These blanket modules, whose dimensions are of the order of the ICRF wavelengths, together with the clearance gaps between them will constitute a corrugated structure which will interact with the electromagnetic waves launched by ICRF antennas. The conditions in which the grooves constituted by the clearance gaps between the blanket modules can become resonant are studied. Simple analytical models and numerical simulations show that mushroom type structures (with larger gaps at the back than at the front) can bring down the resonance frequencies, which could lead to large voltages in the gaps between the blanket modules and perturb the RF properties of the antenna if they are in the ICRF operating range. The effect on the wave propagation along the wall structure, which is acting as a spatially periodic (toroidally and poloidally) corrugated structure, and hence constitutes a slow wave structure modifying the wall boundary condition, is examined.
Development of three-dimensional site-site Smoluchowski-Vlasov equation and application to electrolyte solutions
Authors: Kasahara Kento , Sato Hirofumi
Published: June 2014

Site-site Smoluchowski-Vlasov (SSSV) equation enables us to directly calculate van Hove time correlation function, which describes diffusion process in molecular liquids. Recently, the theory had been extended to treat solute-solvent system by Iida and Sato [J. Chem. Phys. 137, 034506 (2012)]. Because the original framework of SSSV equation is based on conventional pair correlation function, time evolution of system is expressed in terms of one-dimensional solvation structure. Here, we propose a new SSSV equation to calculate time evolution of solvation structure in three-dimensional space. The proposed theory was applied to analyze diffusion processes in 1M NaCl aqueous solution and in lithium ion battery electrolyte solution. The results demonstrate that these processes are properly described with the theory, and the computed van Hove functions are in good agreement with those in previous works.
Total three-dimensional imaging of phase objects using defocusing microscopy: Application to red blood cells
Authors: Roma P. M. S. , Siman L. , Amaral F. T. , Agero U. , Mesquita O. N.
Published: June 2014

We introduce Defocusing Microscopy (DM), a bright-field optical microscopy technique able to perform total three-dimensional (3D) imaging of transparent objects. By total 3D imaging, we mean the determination of the actual shapes of the upper and lower surfaces of a phase object. We propose a methodology using DM and apply it to red blood cells subject to different osmolality conditions: hypotonic, isotonic, and hypertonic solutions. For each situation, the shapes of the upper and lower cell surface-membranes (lipid bilayer/cytoskeleton) are completely recovered, displaying the deformation of red blood cell (RBC) surfaces due to adhesion on the glass-substrate. The axial resolution of our technique allowed us to image surface-membranes separated by distances as small as 300 nm. Finally, we determine the volume, surface area, sphericity index, and RBC refractive index for each osmotic condition.
Ultrafast terahertz-induced response of GeSbTe phase-change materials
Authors: Shu Michael J. , Zalden Peter , Chen Frank , Weems Ben , Chatzakis Ioannis , Xiong Feng , Jeyasingh Rakesh , Hoffmann Matthias C. , Pop Eric , Philip Wong H.-S. , Wuttig Matthias , Lindenberg Aaron M.
Published: June 2014

The time-resolved ultrafast electric field-driven response of crystalline and amorphous GeSbTe films has been measured all-optically, pumping with single-cycle terahertz pulses as a means of biasing phase-change materials on a sub-picosecond time-scale. Utilizing the near-band-gap transmission as a probe of the electronic and structural response below the switching threshold, we observe a field-induced heating of the carrier system and resolve the picosecond-time-scale energy relaxation processes and their dependence on the sample annealing condition in the crystalline phase. In the amorphous phase, an instantaneous electroabsorption response is observed, quadratic in the terahertz field, followed by field-driven lattice heating, with Ohmic behavior up to 200 kV/cm.
Silicon nanocrystals in SiNx/SiO2 hetero-superlattices: The loss of size control after thermal annealing
Authors: Zelenina A. , Sarikov A. , Zhigunov D. M. , Weiss C. , Zakharov N. , Werner P. , López-Conesa L. , Estradé S. , Peiró F. , Dyakov S. A. , Zacharias M.
Published: June 2014

Superlattices containing 3 nm thick silicon rich silicon nitride sublayers and 3 nm and 10 nm thick SiO2 barriers were prepared by plasma enhanced chemical vapor deposition. Despite the as-prepared samples represented a well-kept multilayer structure with smooth interfaces, the high temperature annealing resulted in the total destruction of multilayer structure in the samples containing 3 nm SiO2 barriers. Energy-filtered transmission electron microscopy images of these samples indicated a silicon nanoclusters formation with sizes of 2.5–12.5 nm, which were randomly distributed within the structure. Although in the sample with 10 nm SiO2 barriers some fragments of the multilayer structure could be still observed after thermal annealing, nevertheless, the formation of large nanocrystals with diameters up to 10 nm was confirmed by dark field transmission electron microscopy. Thus, in contrast to the previously published results, the expected size control of silicon nanocrystals was lost. According to the FTIR results, the thermal annealing of SiNx/SiO2 superlattices led to the formation of silicon nanocrystals in mostly oxynitride matrix. Annealed samples demonstrated a photoluminescence peak at 885 nm related to the luminescence of silicon nanocrystals, as confirmed by time-resolved photoluminescence measurements. The loss of nanocrystals size control is discussed in terms of the migration of oxygen atoms from the SiO2 barriers into the silicon rich silicon nitride sublayers. A thermodynamic mechanism responsible for this process is proposed. According to this mechanism, the driving force for the oxygen migration is the gain in the configuration entropy related to the relative arrangements of oxygen and nitrogen atoms.
Communication: The description of strong correlation within self-consistent Green's function second-order perturbation theory
Authors: Phillips Jordan J. , Zgid Dominika
Published: June 2014

We report an implementation of self-consistent Green's function many-body theory within a second-order approximation (GF2) for application with molecular systems. This is done by iterative solution of the Dyson equation expressed in matrix form in an atomic orbital basis, where the Green's function and self-energy are built on the imaginary frequency and imaginary time domain, respectively, and fast Fourier transform is used to efficiently transform these quantities as needed. We apply this method to several archetypical examples of strong correlation, such as a H32 finite lattice that displays a highly multireference electronic ground state even at equilibrium lattice spacing. In all cases, GF2 gives a physically meaningful description of the metal to insulator transition in these systems, without resorting to spin-symmetry breaking. Our results show that self-consistent Green's function many-body theory offers a viable route to describing strong correlations while remaining within a computationally tractable single-particle formalism.
In-silico investigation of Rayleigh instability in ultra-thin copper nanowire in premelting regime
Authors: Dutta Amlan , Chatterjee Swastika , Raychaudhuri A. K. , Moitra Amitava , Saha-Dasgupta T.
Published: June 2014

Motivated by the recent experimental reports, we explore the formation of Rayleigh-like instability in metallic nanowires during the solid state annealing, a concept originally introduced for liquid columns. Our molecular dynamics study using realistic interatomic potential reveals instability induced pattern formation at temperatures even below the melting temperature of the wire, in accordance with the experimental observations. We find that this is driven by the surface diffusion, which causes plastic slips in the system initiating necking in the nanowire. We further find the surface dominated mass-transport is of subdiffusive nature with time exponent less than unity. Our study provides an atomistic perspective of the instability formation in nanostructured solid phase.
Localized spoof plasmons in closed textured cavities
Authors: Li Zhuo , Xu Bingzheng , Gu Changqing , Ning Pingping , Liu Liangliang , Niu Zhenyi , Zhao Yongjiu
Published: June 2014

Localized spoof plasmons arising with textured closed surfaces have been theoretically studied and experimentally verified, which resemble the localized surface plasmons (LSPs) in the optical regime. In this work, we go one step further and demonstrate that part of the resonance modes in closed textured cavities pertain to spoof localized surface plasmons (spoof-LSPs) modes. We show the existence of spoof LSPs in periodically textured perfect electric conductor circular cavities and make an analogy between these spoof LSPs and the real LSPs in closed metallic cavities with the Drude model in the optical regime. Also, a metamaterial approach is presented to capture the resonant features of these modes.
Surface effects on the scattering of compressional waves by a piezoelectric nano-cylinder
Authors: Zhang L. L. , Liu J. X. , Fang X. Q. , Nie G. Q.
Published: June 2014

Based on the surface piezoelectricity model, surface effects on the scattering behaviors of plane compressional waves by an embedded piezoelectric cylinder with nanoscale radius are investigated. The existence of surface stresses and surface electric displacements exerting on the boundary conditions is taken into account through generalized Young-Laplace equations, and the potential function method is employed to derive the analytical expressions of wave fields and electric potential. For two typical incident frequencies, the influence of surface properties on the distribution of electroelastic fields around the cylinder is discussed in detail. In comparison with the results obtained from the classical continuum theories, it is found that the surface effects play a prominent role on the dynamic stress and electric field concentrations, especially under a high-frequency excitation.
Yttria-stabilized zirconia/SrTiO3 oxide heteroepitaxial interface with symmetry discontinuity
Authors: Scigaj M. , Dix N. , Cabero M. , Rivera-Calzada A. , Santamaria J. , Fontcuberta J. , Herranz G. , Sánchez F.
Published: June 2014

We show that yttria-stabilized zirconia (YSZ) films deposited on structurally dissimilar SrTiO3(110) substrates exhibit two-dimensional layer-by-layer growth. We observed that, up to a thickness of about 15 nm, the square (001) basal plane of the cubic YSZ grows epitaxially on the rectangular (110) crystallographic plane of SrTiO3 substrates, with [110]YSZ(001)//[001]SrTiO3(110) epitaxial relationship. Thus, the heterointerface presents symmetry discontinuity between the YSZ(001) film and the lower surface symmetry SrTiO3(110) substrate. Beyond this specific case, we envisage similar approaches to develop other innovative oxide interfaces showing similar crystal symmetry discontinuities.
Co-localised Raman and force spectroscopy reveal the roles of hydrogen bonds and π-π interactions in defining the mechanical properties of diphenylalanine nano- and micro-tubes
Authors: Sinjab Faris , Bondakov Georgi , Notingher Ioan
Published: June 2014

An integrated atomic force and polarized Raman microscope were used to measure the elastic properties of individual diphenylalanine (FF) nano- and micro-tubes and to obtain quantitative information regarding the inter-molecular interactions that define their mechanical properties. For individual tubes, co-localised force spectroscopy and Raman spectroscopy measurements allowed the calculation of the Young's and shear moduli (25 ± 5 GPa and 0.28 ± 0.05 GPa, respectively) and the contribution of hydrogen bonding network to the Young's modulus (∼17.6 GPa). The π-π interactions between the phenyl rings, dominated by T-type arrangements, were estimated based on previously published X-ray data to only 0.20 GPa. These results provide experimental evidence obtained from individual FF tubes that the network of H-bonds dominates the elastic properties of the FF tubes.
Assembled micro-nano particles with multiple interface polarizations for electromagnetic absorption at gigahertz
Authors: Zhang X. F. , Guo J. J. , Qin G. W.
Published: June 2014

The usually utilized electromagnetic absorbers are fabricated by randomly dispersed fillers in polymer matrix, which limit the construction of multiple interfaces, thus influencing the optimization of absorption efficiency. In this Letter, the core/shell heterogeneous nanocapsules are chemically modified and subsequently conjugated on the micrometre-scale polymer units, forming a micro/nano-hybrided absorbent. Such a system creates multiple interfaces at sub-nanoscale, thus producing enhanced dielectric loss phenomena and resulting in an absorption efficiency of more than 90% over 2–18 GHz. The present study provides an effective concept to optimize the electromagnetic coupling and has important implications in the development of electromagnetic absorption materials.
Excellent c-Si surface passivation by low-temperature atomic layer deposited titanium oxide
Authors: Liao Baochen , Hoex Bram , Aberle Armin G. , Chi Dongzhi , Bhatia Charanjit S.
Published: June 2014

In this work, we demonstrate that thermal atomic layer deposited (ALD) titanium oxide (TiOx) films are able to provide a—up to now unprecedented—level of surface passivation on undiffused low-resistivity crystalline silicon (c-Si). The surface passivation provided by the ALD TiOx films is activated by a post-deposition anneal and subsequent light soaking treatment. Ultralow effective surface recombination velocities down to 2.8 cm/s and 8.3 cm/s, respectively, are achieved on n-type and p-type float-zone c-Si wafers. Detailed analysis confirms that the TiOx films are nearly stoichiometric, have no significant level of contaminants, and are of amorphous nature. The passivation is found to be stable after storage in the dark for eight months. These results demonstrate that TiOx films are also capable of providing excellent passivation of undiffused c-Si surfaces on a comparable level to thermal silicon oxide, silicon nitride, and aluminum oxide. In addition, it is well known that TiOx has an optimal refractive index of 2.4 in the visible range for glass encapsulated solar cells, as well as a low extinction coefficient. Thus, the results presented in this work could facilitate the re-emergence of TiOx in the field of high-efficiency silicon wafer solar cells.
Influence of the demagnetizing factor on the magnetocaloric effect: Critical scaling and numerical simulations
Authors: Romero-Muñiz C. , Ipus J. J. , Blázquez J. S. , Franco V. , Conde A.
Published: June 2014

In recent years, the magnetocaloric effect is studied not only for the search of potential magnetic refrigerant materials but also for the analysis of critical phenomena. In both cases, the demagnetizing field might have a notable influence on the results. In this work, we carry out a systematic study, based on theoretical simulations, of the influence of the demagnetizing factor on the magnetocaloric properties. On the one hand, we show that demagnetizing factor affects only slightly the magnetic entropy change (ΔSM), reducing its magnitude and shifting the peak to higher temperatures. On the other hand, it dramatically affects the exponent n of field dependence (ΔSM∝Hn) at temperatures below the peak. We demonstrate that scaling of the magnetocaloric curves can be used to remove the influence of the demagnetizing field and, to which extent, critical exponent determination can be affected. Results of numerical simulations are compared with experimental data from a ball milled powder alloy.