bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of Zr(iv)-based architectures generated from ligands incorporating the 2,2′-biphenolato unit
Authors: Miao Chengrui , Khalil Georges , Chaumont Alain , Mobian Pierre , Henry Marc
Published: April 2016

The architectures generated from 2,2′-biphenol-based proligands and the Zr(iv) centre are identified. The triple-stranded helicate formed in solution contrasts strongly with the helical complex characterised in the solid-state.
Supramolecular exo-functionalized palladium cages: fluorescent properties and biological activity
Authors: Schmidt Andrea , Hollering Manuela , Drees Markus , Casini Angela , Kühn Fritz E.
Published: April 2016

Self-assembled Pd(ii) coordination cages exhibit promising anticancer activities, while the emission properties studied by fluorescence spectroscopy and DFT calculations are limited.
Comparison of H2 photogeneration by [FeFe]-hydrogenase mimics with CdSe QDs and Ru(bpy)3Cl2 in aqueous solution
Authors: Jian Jing-Xin , Ye Chen , Wang Xu-Zhe , Wen Min , Li Zhi-Jun , Li Xu-Bing , Chen Bin , Tung Chen-Ho , Wu Li-Zhu
Published: April 2016

Two simple water soluble [FeFe]-H2ase mimic systems (I and II) were designed to understand the basic principles governing photocatalytic H2 evolution.
Phospholipophilicity of CxHyN+ amines: chromatographic descriptors and molecular simulations for understanding partitioning into membranes
Authors: Droge S. T. J. , Hermens J. L. M. , Rabone J. , Gutsell S. , Hodges G.
Published: April 2016

The contribution of each CHx unit to the overall membrane sorption affinity of an organic cation depends on the most favorable orientation of the sorbed molecule in the bilayer.
Emerging investigators series: prediction of trace organic contaminant abatement with UV/H2O2: development and validation of semi-empirical models for municipal wastewater effluents
Authors: Gerrity Daniel , Lee Yunho , Gamage Sujanie , Lee Minju , Pisarenko Aleksey N. , Trenholm Rebecca A. , von Gunten Urs , Snyder Shane A.
Published: April 2016

Recent evaluations of potable reuse treatment trains suggest that the use of UV and UV/H2O2may become increasingly common, particularly in systems employing ozone and/or biofiltration.
Mechanism, synthesis and modification of nano zerovalent iron in water treatment
Authors: Lu Hai-Jiao , Wang Jing-Kang , Ferguson Steven , Wang Ting , Bao Ying , Hao Hong-xun
Published: April 2016

An overview of the mechanism, synthesis and modification of nano zerovalent iron in water treatment is provided.
Spectral triangulation: a 3D method for locating single-walled carbon nanotubes in vivo
Authors: Lin Ching-Wei , Bachilo Sergei M. , Vu Michael , Beckingham Kathleen M. , Bruce Weisman R.
Published: April 2016

Single-walled carbon nanotubes are detected and located deep inside tissue phantoms using special instrumentation and a new spectral analysis method.
Self-replicating systems
Authors: Clixby Gregory , Twyman Lance
Published: April 2016

A review covering the previous 25 years study into self-replicating systems.
Indolo-quinoline boron difluoride dyes: synthesis and spectroscopic properties
Authors: Luo Hui-Xin , Niu Youhong , Jin Xiaojie , Cao Xiao-Ping , Yao Xiaojun , Ye Xin-Shan
Published: April 2016

Novel indolo-quinoline compounds were prepared, and their corresponding BF2-complexes showed fluorescence with large Stokes shifts.
Synthesis and characterization of poly(N-vinyl-1,2,3-triazole)s derived from monomers obtained by highly efficient Wolff's cyclocondensation
Authors: Wang Zikun , Tao Youhua , Wang Zhen , Yan Jingling
Published: April 2016

High-efficiency synthetic access to poly(N-vinyl-1,2,3-triazole)s has been described via modified Wolff's cyclocondensation.
Synthesis and laboratory testing of a novel calcium-phosphonate reverse micelle nanofluid for oilfield mineral scale control
Authors: Zhang Ping , Shen Dong , Kan Amy T. , Tomson Mason B.
Published: April 2016

Developed calcium-phosphonate scale inhibitor reverse micelle nanomaterial for oilfield mineral scale control in low water cut or water sensitive wells.
Exploration of unconventional π–hole and C–H⋯H–C types of supramolecular interactions in a trinuclear Cd(ii) and a heteronuclear Cd(ii)–Ni(ii) complex and experimental evidence for preferential site selection of the ligand by 3d and 4d metal ions
Authors: Banerjee Saikat , Bauzá Antonio , Frontera Antonio , Saha Amrita
Published: April 2016

We report the synthesis of a trinuclear cadmium(ii) (1) and a di(phenoxido)-bridged dinuclear cadmium(ii)–nickel(ii) (2) complex derived from a bicompartmental (N2O4) Schiff base ligand.
Promising photovoltaic application of multi-walled carbon nanotubes in perovskites solar cells for retarding recombination
Authors: Wang Junxia , Li Jingling , Xu Xueqing , Bi Zhuoneng , Xu Gang , Shen Honglie
Published: April 2016

With MWCNTs incorporating spiro-OMeTAD, it exhibits a Jsc of 22.13 mA cm−2 and PCE of 10.42% and the optical absorption performance, charge transfer and recombination performance were investigated in order to infer the origin of increasing Jsc and PCE.
Synthesis, characterization and antitumor activity of novel tetrapodal 1,4-dihydropyridines: p53 induction, cell cycle arrest and low damage effect on normal cells induced by genotoxic factor H2O2
Authors: Mohamed Magda F. , Darweesh Ahmed F. , Elwahy Ahmed H. M. , Abdelhamid Ismail A.
Published: April 2016

Synthesis of novel tetrakis(2,6-dimethyl-4-phenyl-1,4-dihydropyridinyl)methanes5a–dby acid-catalyzed condensation of the tetrakis-aldehydes6a–dwith eight equivalents of 3-aminobut-2-enenitrile2is reported. Antitumor activities of compounds5a–dwere also investigated.
Copolymerization of l-lactide/trimethylene carbonate by organocatalysis: controlled synthesis of comb-like graft copolymers with side chains with different topologies
Authors: Leng Xuefei , Wei Zhiyong , Ren Yingying , Bian Yufei , Wang Qinyi , Li Yang
Published: April 2016

Synthesis of comb-like graft copolymers of lcP(LLA-co-TMC) from an organocatalyst/PB–OH system: including lcP(TMC-b-LLA), lcP(LLA-grad-TMC) and lcP(LLA-ran-TMC).
Facile and green decoration of Pd nanoparticles on macroporous carbon by polyoxometalate with enhanced electrocatalytic ability
Authors: Zhang Yufan , Wang Huan , Yao Qianqian , Yan Fei , Cui Chunyan , Sun Mengyuan , Zhang Hongyi
Published: April 2016

A well-defined Pd nanoparticles@polyoxometalates/macroporous carbon (Pd@POMs/MPC) tri-component nanohybrid has been developed using a facile, green, and one-pot synthesis method.
Tuneable mechanical and dynamical properties in the ferroelectric perovskite solid solution [NH3NH2]1−x[NH3OH]xZn(HCOO)3
Authors: Kieslich Gregor , Kumagai Shohei , Forse Alexander C. , Sun Shijing , Henke Sebastian , Yamashita Masahiro , Grey Clare P. , Cheetham Anthony K.
Published: April 2016

We report how mechanical and dynamical properties in formate-based perovskites can be manipulated by the preparation of an A-site solid-solution.
Soy protein-directed one-pot synthesis of gold nanomaterials and their functional conductive devices
Authors: Ling Shengjie , Liang Heyi , Li Zhao , Ma Li , Yao Jinrong , Shao Zhengzhong , Chen Xin
Published: April 2016

Gold nanomaterials were synthesized via a facile and green method, using soy protein isolate as reductant, template, and capping agent.
Secondary School Teachers' Beliefs, Attitudes, and Reactions to Stuttering
Authors: Adriaensens Stefanie , Struyf Elke
Published: April 2016

Purpose

The study identifies teachers' beliefs about and attitudes toward stuttering and explores to what extent these beliefs and attitudes prompt specific teachers' reactions to the stuttering of a student.

Method

Participants were teachers in secondary education in Flanders (Belgium), currently teaching an adolescent who stutters. They were the student's class teacher or instructed a course in which communication is important. Ten semistructured interviews were conducted and analyzed thematically.

Results

Teachers believed that (a) when peers do not react to the stuttering, the lesson is not disrupted by it, and the student who stutters participates in the lesson, stuttering is not necessarily a problem; (b) when attention is paid to it, stuttering can become a problem; (c) they try to react as little as possible to the stuttering; and (d) they seldom talk about the stuttering.

Conclusion

Although teachers reported that they feel confident in how to deal with stuttering, and although it is possible that students who stutter do not feel the need to talk about their stuttering, teachers could consult their students on this matter. This way, they would acknowledge the stuttering and likely encourage the students to approach them when they feel the need.
Gate‐drive circuit with efficient energy recovery based on DC/DC converter
Authors: Yu Juzheng , Liu Peng , Qian Qinsong , Sun Weifeng , Lu Shengli
Published: April 2016

A gate driver with efficient energy recovery based on bidirectional buck/boost converter is proposed. The proposed gate‐drive circuit is constructed by power supply, energy storage module and energy converter. Instead of discharging directly in conventional gate drivers, gate charge Qg in the proposed gate driver is released to the storage capacitor during turning‐off transition of power MOSFET. Principle of the proposed gate driver is analysed, and design consideration of key parameters are also suggested. The gate‐drive losses of the proposed gate driver and resonant gate driver are, respectively, tested as 0.102 and 0.125 W at 100 kHz. The test result proves that power consumption of the proposed gate driver is significantly decreased.
Highly localised near orthogonal graph wavelets
Authors: Tay D.B.H. , Lin Z.
Published: April 2016

The processing of signals defined over domains modelled as graphs is becoming a fast emerging area of research. A graph filter bank allows for the wavelet transform on graph signals that is similar to the discrete wavelet transform (DWT) for regular domain signals. Localisation is an important property of the transform and the most localised DWT is with the Haar wavelets. Spectral graph filters that are highly localised is constructed. These filters can be considered as the counterparts to the Haar filters in DWT.
Estimation of electromagnetic field in air by a magnetic dipole in the sea based on a current sheet model
Authors: Wang Honglei , Yang Kunde , Zheng Kun , Yang Yixin , Ma Yuanliang
Published: April 2016

Considerable efforts have been made to investigate the electromagnetic (EM) field in air produced by a magnetic dipole in sea. The conventional methods for this investigation mostly involve complicated analysis of Sommerfeld‐type integrals. To conveniently provide a meaningful physical explanation of the EM field radiation in a two‐layered media, this study considers a current sheet at the sea‐to‐air interface created by an underwater magnetic dipole. This current behaves like an antenna located on the surface and creates a wave that propagates through the atmosphere. Analysis of this current sheet can take advantage of the Huygens–Fresnel principle. The results using this approach can be verified by previous calculation and experiments on the sea, and show good agreement with experimental data. The present approach, which involves simple algebra, can easily explain the physical aspect of the EM wave propagation across the sea‐to‐air interface.
Compact beam‐reconfigurable feed for large aperture antennas
Authors: Moghadas Hamid , Daneshmand Mojgan , Mousavi Pedram
Published: April 2016

This study presents a novel compact beam‐reconfigurable horn antenna using a fully operational MEMS‐tuned partially reflective surface (PRS). Two symmetric MEMS capacitive switches across a slot on a single layer patch PRS tune its reflection and enable the dynamic reconfiguration of the horn pattern. The authors explore the potential of this PRS in two different applications: beamwidth and beam‐shape reconfiguration. Furthermore, a novel in‐house process for monolithic fabrication of the MEMS‐integrated full PRS and a dedicated DC bias network is developed and analysed. The proposed structure can be used as the feed of a reflector, reflectarray or transmittarray to control the aperture illumination and allow beam‐reconfiguration.
Response of a resonant tunnelling diode optoelectronic oscillator coupled to a non‐linear electrical circuit
Authors: Thepi Siewe Raoul , Talla Alain Francis , Woafo Paul
Published: April 2016

In this study, the authors present a numerical study of the dynamics of a non‐linear optoelectronic oscillator (OEO) based on the resonant tunnelling diode (RTD) oscillator incorporating a photo‐detector and coupled to a non‐linear electrical circuit. In the first part, it is found that the RTD‐OEO oscillator presents periodic and quasiperiodic behaviours depending on the values of the parameters of a pulse‐like optical signal. In the second part where the RTD‐OEO is coupled to the Van der Pol oscillator, the dynamics present a variety of states including bursting, relaxation and sinusoidal oscillations.
Designing a robust backstepping controller for rehabilitation in Parkinson's disease: a simulation study
Authors: Rouhollahi Korosh , Emadi Andani Mehran , Karbassi Seyed Mahdi , Izadi Iman
Published: April 2016

In this study, a model of basal ganglia (BG) is applied to develop a deep brain stimulation controller to reduce Parkinson's tremor. Conventionally, one area in BG is stimulated, with no feedback, to control Parkinson's tremor. In this study, a new architecture is proposed to develop feedback controller as well as to stimulate two areas of BG simultaneously. To this end, two controllers are designed and implemented in globus pallidus internal (GPi) and subthalamic nucleus (STN) in the brain. A proportional controller and a backstepping controller are designed and implemented in GPi and STN, respectively. The proposed controllers deliver suitable stimulatory control signals to GPi and STN based on hand tremor amplitude (as the feedback). When tremor reduces, these controllers decrease the stimulatory energy intensity proportionally. Therefore, additional stimulatory signal is not delivered to the brain. Subsequently, the side effects from the excessive stimulation intensity become much less. Comparing with one area stimulation, the results show that stimulating two areas of BG results in reduction of the level of the stimulation intensity. It is observed that these two controllers are both robust in terms of changing the system parameters.
A Web Site to Improve Management of Patients with Inherited Bleeding Disorders in the Emergency Department: Results at 2 Years
Authors: Tagliaferri Annarita , Di Perna Caterina , Biasoli Chiara , Rivolta Gianna , Quintavalle Gabriele , Cervellin Gianfranco , Barozzi Marco , Benedettini Laura , Pattacini Corrado ,   for the Haemophilia Centres and Emergency Department Network of the Region of Emilia-Romagna
Published: April 2016

Treatment of patients with inherited bleeding disorders (PWIBD) in the emergency department (ED) is challenging. In 2010, a project was started involving all eight hemophilia centers (HC) and all 44 EDs of the Region of Emilia-Romagna (Italy) to improve emergency care for PWIBD. The project incorporates guidelines for emergency treatment, education for ED staff, and a dedicated Web site providing extensive information, proposing treatments, and sharing data with patients' electronic clinical records. A Web algorithm, accessible to PWIBD as well as ED and HC staff, suggests the first dose of concentrate for each type and severity of bleed or trauma. Following training courses in each ED, the network was activated. During 2012 and 2013, the site was visited 14,000 times, the EDs accessed the Web site 1,739 times, and used the algorithms 206 times. In two reference EDs, triage-assessment and triage-treatment times were reduced in 2013 and 2012 (27/20 and 110/71.5 minutes, respectively) and medical advice from the HC increased (54 vs. 24% cases). The main advantages of this system are better management of patients in ED (shorter triage-to-treatment times) and improved collaboration between HCs and EDs. The most critical point remaining is staff turnover in EDs, necessitating continual training.
Im Rampenlicht
Authors: Mau Jens
Published: April 2016

Die Zeit, in der die IT im Krankenhaus eine Nebenrolle eingenommen hat, neigt sich spürbar dem Ende zu. Die IT rückt ins Rampenlicht.
Teamwork im OP
Authors: Kucera Martin
Published: April 2016

Immer mehr Medizintechnikhersteller vereinen die Funktionen einzelner Geräte in Hybridsystemen. Das gilt auch für den hochfokussierten Ultraschall. Er lässt sich nicht nur mit der Magnetresonanztomographie (MRT) verbinden, sondern sogar mit einem Elektroskalpell. Das bietet den Anwendern gleich vier Funktionen in einem Gerät.
Observation of b2 symmetry vibrational levels of the SO2 C̃ 1B2 state: Vibrational level staggering, Coriolis interactions, and rotation-vibration constants
Authors: Park G. Barratt , Jiang Jun , Saladrigas Catherine A. , Field Robert W.
Published: April 2016

The C̃ 1B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. However, low-lying levels with odd quanta of antisymmetric stretch (b2 vibrational symmetry) have not previously been observed because transitions into these levels from the zero-point level of the X̃ state are vibronically forbidden. We use IR-UV double resonance to observe the b2 vibrational levels of the C̃ state below 1600 cm−1 of vibrational excitation. This enables a direct characterization of the vibrational level staggering that results from the double-minimum potential. In addition, it allows us to deperturb the strong c-axis Coriolis interactions between levels of a1 and b2 vibrational symmetry and to determine accurately the vibrational dependence of the rotational constants in the distorted C̃ electronic state.
Drop impact on a fiber
Authors: Kim Sung-Gil , Kim Wonjung
Published: April 2016

We present the results of a combined experimental and theoretical investigation of drop impact on a thin fiber. Using high-speed videography, we analyze the dynamics of droplet collision with a fiber. Based on the systematic experiments, we identify three outcomes of collision: capturing, single drop falling, and splitting. The outcomes are presented in a regime map, where the regime boundaries are explained through a scale analysis of forces. We also measure the liquid retention on the fiber after the droplet impact. By considering a liquid film on the fiber, we develop a mechanical model that predicts the residual water mass. Our model reveals that the residual mass depends critically on the fiber thickness and less on the impact speed. Our study can be extended to predicting the remaining droplet, critical problems in air filtration, water collection, and fiber coating.
Bi-HKT and bi-Kähler supersymmetric sigma models
Authors: Fedoruk Sergey , Smilga Andrei
Published: April 2016

We study Clifford Kähler with torsion (or bi-HKT) N=4 supersymmetric quantum mechanical sigma models. They are characterized by the usual and the mirror sectors displaying each HKT geometry. When the metric involves isometries, a Hamiltonian reduction is possible. The most natural such reduction with respect to a half of bosonic target space coordinates produces an N=4 model, related to the twisted Kähler model due to Gates, Hull and Rocek, but including certain extra F-terms in the superfield action.
Level crossing analysis of chemically induced dynamic nuclear polarization: Towards a common description of liquid-state and solid-state cases
Authors: Sosnovsky Denis V. , Jeschke Gunnar , Matysik Jörg , Vieth Hans-Martin , Ivanov Konstantin L.
Published: April 2016

Chemically Induced Dynamic Nuclear Polarization (CIDNP) is an efficient method of creating non-equilibrium polarization of nuclear spins by using chemical reactions, which have radical pairs as intermediates. The CIDNP effect originates from (i) electron spin-selective recombination of radical pairs and (ii) the dependence of the inter-system crossing rate in radical pairs on the state of magnetic nuclei. The CIDNP effect can be investigated by using Nuclear Magnetic Resonance (NMR) methods. The gain from CIDNP is then two-fold: it allows one to obtain considerable amplification of NMR signals; in addition, it provides a very useful tool for investigating elusive radicals and radical pairs. While the mechanisms of the CIDNP effect in liquids are well established and understood, detailed analysis of solid-state CIDNP mechanisms still remains challenging; likewise a common theoretical frame for the description of CIDNP in both solids and liquids is missing. Difficulties in understanding the spin dynamics that lead to the CIDNP effect in the solid-state case are caused by the anisotropy of spin interactions, which increase the complexity of spin evolution. In this work, we propose to analyze CIDNP in terms of level crossing phenomena, namely, to attribute features in the CIDNP magnetic field dependence to Level Crossings (LCs) and Level Anti-Crossings (LACs) in a radical pair. This approach allows one to describe liquid-state CIDNP; the same holds for the solid-state case where anisotropic interactions play a significant role in CIDNP formation. In solids, features arise predominantly from LACs, since in most cases anisotropic couplings result in perturbations, which turn LCs into LACs. We have interpreted the CIDNP mechanisms in terms of the LC/LAC concept. This consideration allows one to find analytical expressions for a wide magnetic field range, where several different mechanisms are operative; furthermore, the LAC description gives a way to determine CIDNP sign rules. Thus, LCs/LACs provide a consistent description of CIDNP in both liquids and solids with the prospect of exploiting it for the analysis of short-lived radicals and for optimizing the polarization level.
Assessing the potential of group 13 and 14 metal/metalloid phthalocyanines as hole transport layers in organic light emitting diodes
Authors: Plint Trevor , Lessard Benoît H. , Bender Timothy P.
Published: April 2016

In this study, we have assessed the potential application of group 13 and 14 metal and metalloid phthalocyanines ((X)n-MPcs) and their axially substituted derivatives as hole-transporting layers in organic light emitting diodes (OLEDs). OLEDs studied herein have the generic structure of glass/ITO/(N,N′-di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) or (X)n-MPc)(50 nm)/Alq3 (60 nm)/LiF (1 nm)/Al (80 nm), where X is an axial substituent group. OLEDs using chloro aluminum phthalocyanine (Cl-AlPc) showed good peak luminance values of 2620 ± 113 cd/m2 at 11 V. To our knowledge, Cl-AlPc has not previously been shown to work as a hole transport material (HTL) in OLEDs. Conversely, the di-chlorides of silicon, germanium, and tin phthalocyanine (Cl2-SiPc, Cl2-GePc, and Cl2-SnPc, respectively) showed poor performance compared to Cl-AlPc, having peak luminances of only 38 ± 4 cd/m2 (12 V), 23 ± 1 cd/m2 (8.5 V), and 59 ± 5 cd/m2 (13.5 V), respectively. However, by performing a simple axial substitution of the chloride groups of Cl2-SiPc with pentafluorophenoxy groups, the resulting bis(pentafluorophenoxy) silicon phthalocyanine (F10-SiPc) containing OLED had a peak luminance of 5141 ± 941 cd/m2 (10 V), a two order of magnitude increase over its chlorinated precursor. This material showed OLED characteristics approaching those of a baseline OLED based on the well-studied triarylamine NPB. Attempts to attach the pentafluorophenoxy axial group to both SnPc and GePc were hindered by synthetic difficulties and low thermal stability, respectively. In light of the performance improvements observed by simple axial substitution of SiPc in OLEDs, the use of axially substituted MPcs in organic electronic devices remains of continuing interest to us and potentially the field in general.
Plasmon transmission through excitonic subwavelength gaps
Authors: Sukharev Maxim , Nitzan Abraham
Published: April 2016

We study the transfer of electromagnetic energy across a subwavelength gap separating two co-axial metal nanorods. In the absence of spacer in the gap separating the rods, the system exhibits strong coupling behavior between longitudinal plasmons in the two rods. The nature and magnitude of this coupling are studied by varying various geometrical parameters. As a function of frequency, the transmission is dominated by a split longitudinal plasmon peak. The two hybrid modes are the dipole-like “bonding” mode characterized by a peak intensity in the gap and a quadrupole-like “antibonding” mode whose amplitude vanishes at the gap center. When the length of one rod is varied, this mode spectrum exhibits the familiar anti-crossing behavior that depends on the coupling strength determined by the gap width. When off-resonant 2-level emitters are placed in the gap, almost no effect on the frequency dependent transmission is observed. In contrast, when the molecular system is resonant with the plasmonic line shape, the transmission is strongly modified, showing characteristics of strong exciton-plasmon coupling. Most strongly modified is the transmission near the lower frequency “bonding” plasmon mode. The presence of resonant molecules in the gap affects not only the molecule-field interaction but also the spatial distribution of the field intensity and the electromagnetic energy flux across the junction.
Structure and phase behavior of polymer loaded non-ionic and anionic microemulsions
Authors: Weber Andreas , Stühn Bernd
Published: April 2016

We investigate the structure and phase behavior of C12E4 based reverse water in octane microemulsions with small angle x-ray scattering and small angle neutron scattering experiments to explore the phase diagram of the droplet structure. In the regime of stable droplets, these droplets are loaded with the hydrophilic polymer polyethyleneoxide (MW = 1500 g/mol) and compared with microemulsions based on the anionic surfactant AOT. In the small angle neutron scattering experiments, we use shell contrast to focus on the surfactant shell and its variation with addition of polymer. We observe, as predicted by indirect measurements such as dielectric spectroscopy, that the polymer interacts differently with a nonionic or an anionic surfactant shell: In the former case the addition of polymer does not seem to affect the surfactant shell. In the latter case, the obtained scattering data show that the anionic surfactant layer is strongly influenced leading to a higher polydispersity which may be attributed to a floppier surfactant shell.
The rotation-vibration structure of the SO2 C̃1B2 state explained by a new internal coordinate force field
Authors: Jiang Jun , Park G. Barratt , Field Robert W.
Published: April 2016

A new quartic force field for the SO2 C̃ 1B2 state has been derived, based on high resolution data from S16O2 and S18O2. Included are eight b2 symmetry vibrational levels of S16O2 reported in the first paper of this series [G. B. Park et al., J. Chem. Phys. 144, 144311 (2016)]. Many of the experimental observables not included in the fit, such as the Franck-Condon intensities and the Coriolis-perturbed effective C rotational constants of highly anharmonic C̃ state vibrational levels, are well reproduced using our force field. Because the two stretching modes of the C̃ state are strongly coupled via Fermi-133 interaction, the vibrational structure of the C̃ state is analyzed in a Fermi-system basis set, constructed explicitly in this work via partial diagonalization of the vibrational Hamiltonian. The physical significance of the Fermi-system basis is discussed in terms of semiclassical dynamics, based on study of Fermi-resonance systems by Kellman and Xiao [J. Chem. Phys. 93, 5821 (1990)]. By diagonalizing the vibrational Hamiltonian in the Fermi-system basis, the vibrational characters of all vibrational levels can be determined unambiguously. It is shown that the bending mode cannot be treated separately from the coupled stretching modes, particularly at vibrational energies of more than 2000 cm−1. Based on our force field, the structure of the Coriolis interactions in the C̃ state of SO2 is also discussed. We identify the origin of the alternating patterns in the effective C rotational constants of levels in the vibrational progressions of the symmetry-breaking mode, νβ (which correlates with the antisymmetric stretching mode in our assignment scheme).
The origin of unequal bond lengths in the C̃1B2 state of SO2: Signatures of high-lying potential energy surface crossings in the low-lying vibrational structure
Authors: Park G. Barratt , Jiang Jun , Field Robert W.
Published: April 2016

The C̃1B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. The asymmetry in the potential energy surface is expressed as a staggering in the energy levels of the ν3′ progression. We have recently made the first observation of low-lying levels with odd quanta of v3′, which allows us—in the current work—to characterize the origins of the level staggering. Our work demonstrates the usefulness of low-lying vibrational level structure, where the character of the wavefunctions can be relatively easily understood, to extract information about dynamically important potential energy surface crossings that occur at much higher energy. The measured staggering pattern is consistent with a vibronic coupling model for the double-minimum, which involves direct coupling to the bound 2 1A1 state and indirect coupling with the repulsive 3 1A1 state. The degree of staggering in the ν3′ levels increases with quanta of bending excitation, which is consistent with the approach along the C̃ state potential energy surface to a conical intersection with the 2 1A1 surface at a bond angle of ∼145°.
Dynamics and fragmentation of van der Waals and hydrogen bonded cluster cations: (NH3)n and (NH3BH3)n ionized at 10.51 eV
Authors: Yuan Bing , Shin Joong-Won , Bernstein Elliot R.
Published: April 2016

A 118 nm laser is employed as a high energy, single photon (10.51 eV/photon) source for study of the dynamics and fragmentation of the ammonia borane (NH3BH3) cation and its cluster ions through time of flight mass spectrometry. The behavior of ammonia ion and its cluster ions is also investigated under identical conditions in order to explicate the ammonia borane results. Charge distributions, molecular orbitals, and spin densities for (NH3BH3)n and its cations are explored at both the second-order perturbation theory (MP2) and complete active space self-consistent field (CASSCF) theory levels. Initial dissociation mechanisms and potential energy surfaces for ionized NH3BH3, NH3, and their clusters are calculated at the MP2/6-311++G(d,p) level. Protonated clusters (NH3)xH+ dominate ammonia cluster mass spectra: our calculations show that formation of (NH3)n−1H+ and NH2 from the nascent (NH3)n+ has the lowest energy barrier for the system. The only common features for the (NH3)n+ and (NH3BH3)n+ mass spectra under these conditions are found to be NHy+ (y = 0,…,4) at m/z = 14–18. Molecular ions with both 11B and 10B isotopes are observed, and therefore, product ions observed for the (NH3BH3)n cluster system derive from (NH3BH3)n clusters themselves, not from the NH3 moiety of NH3BH3 alone. NH3BH2+ is the most abundant ionization product in the (NH3BH3)n+ cluster spectra: calculations support that for NH3BH3+, an H atom is lost from the BH3 moiety with an energy barrier of 0.67 eV. For (NH3BH3)2+ and (NH3BH3)3+ clusters, a Bδ+⋯Hδ−⋯δ−H⋯δ+B bond can form in the respective cluster ions, generating a lower energy, more stable ion structure. The first step in the (NH3BH3)n+ (n = 2, 3) dissociation is the breaking of the Bδ+⋯Hδ−⋯δ−H⋯δ+B moiety, leading to the subsequent release of H2 from the latter cluster ion. The overall reaction mechanisms calculated are best represented and understood employing a CASSCF natural bond orbital description of the valence electron distribution for the various clusters and monomers. Comparison of the present results with those found for solid NH3BH3 suggests that NH3BH3 can be a good hydrogen storage material.
Ion-acoustic shocks with self-regulated ion reflection and acceleration
Authors: Malkov M. A. , Sagdeev R. Z. , Dudnikova G. I. , Liseykina T. V. , Diamond P. H. , Papadopoulos K. , Liu C.-S. , Su J. J.
Published: April 2016

An analytic solution describing an ion-acoustic collisionless shock, self-consistently with the evolution of shock-reflected ions, is obtained. The solution extends the classic soliton solution beyond a critical Mach number, where the soliton ceases to exist because of the upstream ion reflection. The reflection transforms the soliton into a shock with a trailing wave and a foot populated by the reflected ions. The solution relates parameters of the entire shock structure, such as the maximum and minimum of the potential in the trailing wave, the height of the foot, as well as the shock Mach number, to the number of reflected ions. This relation is resolvable for any given distribution of the upstream ions. In this paper, we have resolved it for a simple “box” distribution. Two separate models of electron interaction with the shock are considered. The first model corresponds to the standard Boltzmannian electron distribution in which case the critical shock Mach number only insignificantly increases from M≈1.6 (no ion reflection) to M≈1.8 (substantial reflection). The second model corresponds to adiabatically trapped electrons. They produce a stronger increase, from M≈3.1 to M≈4.5. The shock foot that is supported by the reflected ions also accelerates them somewhat further. A self-similar foot expansion into the upstream medium is described analytically.
Interdiffusion and stress development in single-crystalline Pd/Ag bilayers
Authors: Noah Martin A. , Flötotto David , Wang Zumin , Mittemeijer Eric J.
Published: April 2016

Interdiffusion and stress evolution in single-crystalline Pd/single-crystalline Ag thin films were investigated by Auger electron spectroscopy sputter-depth profiling and in-situ X-ray diffraction, respectively. The concentration-dependent chemical diffusion coefficient, as well as the impurity diffusion coefficient of Ag in Pd could be determined in the low temperature range of 356 °C–455 °C. As a consequence of the similarity of the strong concentration-dependences of the intrinsic diffusion coefficients, the chemical diffusion coefficient varies only over three orders of magnitude over the whole composition range, despite the large difference of six orders of magnitude of the self-diffusion coefficients of Ag in Ag and Pd in Pd. It is shown that the Darken-Manning treatment should be adopted for interpretation of the experimental data; the Nernst-Planck treatment yielded physically unreasonable results. Apart from the development of compressive thermal stress, the development of stress in both sublayers separately could be ascribed to compositional stress (tensile in the Ag sublayer and compressive in the Pd sublayer) and dominant relaxation processes, especially in the Ag sublayer. The effect of these internal stresses on the values determined for the diffusion coefficients is shown to be negligible.
A continuous dry 300 mK cooler for THz sensing applications
Authors: Klemencic G. M. , Ade P. A. R. , Chase S. , Sudiwala R. , Woodcraft A. L.
Published: April 2016

We describe and demonstrate the automated operation of a novel cryostat design that is capable of maintaining an unloaded base temperature of less than 300 mK continuously, without the need to recycle the gases within the final cold head, as is the case for conventional single shot sorption pumped 3He cooling systems. This closed dry system uses only 5 l of 3He gas, making this an economical alternative to traditional systems where a long hold time is required. During testing, a temperature of 365 mK was maintained with a constant 20 μW load, simulating the cooling requirement of a far infrared camera.
Cage effect in supercooled molecular liquids: Local anisotropies and collective solid-like response
Authors: Bernini S. , Leporini D.
Published: April 2016

Both local geometry and collective extended excitations drive the moves of a particle in the cage of its neighbours in dense liquids. The strength of their influence is investigated by the molecular dynamics simulations of a supercooled liquid of fully flexible trimers with semirigid or rigid bonds. The rattling in the cage is investigated on different length scales. First, the rattling anisotropy due to local order is characterized by two order parameters sensing the monomers succeeding or failing to escape from the cage. Then the collective response of the surroundings excited by the monomer-monomer collisions is considered. The collective response is initially restricted to the nearest neighbours of the colliding particle by a Voronoi analysis revealing elastic contributions. Then the long-range excitation of the farthest neighbours is scrutinised by searching spatially extended correlations between the simultaneously fast displacements of the caged particle and the surroundings. It is found that the longitudinal component has stronger spatial modulation than the transverse one with a wavelength of about one particle diameter, in close resemblance with experimental findings on colloids. It is concluded that the cage rattling is largely affected by solid-like extended modes.
New insights into photodissociation dynamics of cyclobutanone from the AIMS dynamic simulation
Authors: Liu Lihong , Fang Wei-Hai
Published: April 2016

In this work, the combined electronic structure calculations and non-adiabatic dynamics simulations were performed for understanding mechanistic photodissociation of cyclobutanone at ∼248 nm. Besides the stationary and intersection structures reported before, two new conical intersections between the ground (S0) and the first excited singlet (S1) states were determined in the present study, which were confirmed to be the new S1 → S0 funnels by the ab initio multiple spawning dynamic simulation, giving rise to products in the S0 state selectively. The time evolution of the S1 electronic population was fitted with the pure exponential formulae, from which the S1 lifetime was estimated to be 484.0 fs. The time constant for the S1 α-cleavage is calculated to be 176.6 fs, which is based on the present dynamics simulation. As a result of the ultrafast S1 processes, the statistical distribution of the excess energies is prevented in the S1 state. The S1 dynamic effect (the nonergodic behavior) was predicted to be an important factor that is responsible for the wavelength dependence of the branching ratio of photodissociation products, which will be discussed in detail.
Flywheel induction motor-generator for magnet power supply in small fusion device
Authors: Hatakeyma S. , Yoshino F. , Tsutsui H. , Tsuji-Iio S.
Published: April 2016

A flywheel motor-generator (MG) for the toroidal field (TF) coils of a small fusion device was developed which utilizes a commercially available squirrel-cage induction motor. Advantages of the MG are comparably-long duration, quick power response, and easy implementation of power control compared with conventional capacitor-type power supply. A 55-kW MG was fabricated, and TF coils of a small fusion device were energized. The duration of the current flat-top was extended to 1 s which is much longer than those of conventional small devices (around 10–100 ms).
Direct observation in 3d of structural crossover in binary hard sphere mixtures
Authors: Statt Antonia , Pinchaipat Rattachai , Turci Francesco , Evans Robert , Royall C. Patrick
Published: April 2016

For binary fluid mixtures of spherical particles in which the two species are sufficiently different in size, the dominant wavelength of oscillations of the pair correlation functions is predicted to change from roughly the diameter of the large species to that of the small species along a sharp crossover line in the phase diagram [C. Grodon et al., J. Chem. Phys. 121, 7869 (2004)]. Using particle-resolved colloid experiments in 3d we demonstrate that crossover exists and that its location in the phase diagram is in quantitative agreement with the results of both theory and our Monte-Carlo simulations. In contrast with previous work [J. Baumgartl et al., Phys. Rev. Lett. 98, 198303 (2007)], where a correspondence was drawn between crossover and percolation of both species, in our 3d study we find that structural crossover is unrelated to percolation.
Generation of strong pulsed magnetic fields using a compact, short pulse generator
Authors: Yanuka D. , Efimov S. , Nitishinskiy M. , Rososhek A. , Krasik Ya. E.
Published: April 2016

The generation of strong magnetic fields (∼50 T) using single- or multi-turn coils immersed in water was studied. A pulse generator with stored energy of ∼3.6 kJ, discharge current amplitude of ∼220 kA, and rise time of ∼1.5 μs was used in these experiments. Using the advantage of water that it has a large Verdet constant, the magnetic field was measured using the non-disturbing method of Faraday rotation of a polarized collimated laser beam. This approach does not require the use of magnetic probes, which are sensitive to electromagnetic noise and damaged in each shot. It also avoids the possible formation of plasma by either a flashover along the conductor or gas breakdown inside the coil caused by an induced electric field. In addition, it was shown that this approach can be used successfully to investigate the interesting phenomenon of magnetic field enhanced diffusion into a conductor.
A high performance transparent resistive switching memory made from ZrO2/AlON bilayer structure
Authors: Tsai Tsung-Ling , Chang Hsiang-Yu , Lou Jesse Jen-Chung , Tseng Tseung-Yuen
Published: April 2016

In this study, the switching properties of an indium tin oxide (ITO)/zirconium oxide (ZrO2)/ITO single layer device and those of a device with an aluminum oxynitride (AlON) layer were investigated. The devices with highly transparent characteristics were fabricated. Compared with the ITO/ZrO2/ITO single layer device, the ITO/ZrO2/AlON/ITO bilayer device exhibited a larger ON/OFF ratio, higher endurance performance, and superior retention properties by using a simple two-step forming process. These substantial improvements in the resistive switching properties were attributed to the minimized influence of oxygen migration through the ITO top electrode (TE), which can be realized by forming an asymmetrical conductive filament with the weakest part at the ZrO2/AlON interface. Therefore, in the ITO/ZrO2/AlON/ITO bilayer device, the regions where conductive filament formation and rupture occur can be effectively moved from the TE interface to the interior of the device.
Two decades of progress in understanding and control of laser plasma instabilities in indirect drive inertial fusion
Authors: Montgomery David S.
Published: April 2016

Our understanding of laser-plasma instability (LPI) physics has improved dramatically over the past two decades through advancements in experimental techniques, diagnostics, and theoretical and modeling approaches. We have progressed from single-beam experiments—ns pulses with ∼kJ energy incident on hundred-micron-scale target plasmas with ∼keV electron temperatures—to ones involving nearly 2 MJ energy in 192 beams onto multi-mm-scale plasmas with temperatures ∼4 keV. At the same time, we have also been able to use smaller-scale laser facilities to substantially improve our understanding of LPI physics and evaluate novel approaches to their control. These efforts have led to a change in paradigm for LPI research, ushering in an era of engineering LPI to accomplish specific objectives, from tuning capsule implosion symmetry to fixing nonlinear saturation of LPI processes at acceptable levels to enable the exploration of high energy density physics in novel plasma regimes. A tutorial is provided that reviews the progress in the field from the vantage of the foundational LPI experimental results. The pedagogical framework of the simplest models of LPI will be employed, but attention will also be paid to settings where more sophisticated models are needed to understand the observations. Prospects for the application of our improved understanding for inertial fusion (both indirect- and direct-drive) and other applications will also be discussed.
Elastic properties of gold supracrystals: Effects of nanocrystal size, ligand length, and nanocrystallinity
Authors: Liu X. P. , Ni Y. , He L. H.
Published: April 2016

Atomistic molecular dynamics simulations are performed to study the elastic properties of alkylthiol-functionalized gold supracrystals. The predicted Young’s and shear moduli are around 1 GPa and 100 MPa, respectively. We show that, with increasing NC size, the Young’s modulus decreases while the shear modulus essentially remains invariant; with increasing ligand length, the Young’s modulus increases but the shear modulus decreases. Moreover, significant increase in the Young’s modulus is seen when the polycrystalline NCs are replaced by single-crystal ones of the same size. All these are in reasonable agreement with available experiments. We attribute the mechanisms to the interaction between capping ligands as well as its variations caused by the change in ligand length and NC geometry. The results may deepen our understanding of elastic properties of the supracrystals and their influential factors.
Electrical and morphological characterization of transfer-printed Au/Ti/TiOx/p+-Si nano- and microstructures with plasma-grown titanium oxide layers
Authors: Weiler Benedikt , Nagel Robin , Albes Tim , Haeberle Tobias , Gagliardi Alessio , Lugli Paolo
Published: April 2016

Highly-ordered, sub-70 nm-MOS-junctions of Au/Ti/TiOx/p+-Si were efficiently and reliably fabricated by nanotransfer-printing (nTP) over large areas and their functionality was investigated with respect to their application as MOS-devices. First, we used a temperature-enhanced nTP process and integrated the plasma-oxidation of a nm-thin titanium film being e-beam evaporated directly on the stamp before the printing step without affecting the p+-Si substrate. Second, morphological investigations (scanning electron microscopy) of the nanostructures confirm the reliable transfer of Au/Ti/TiOx-pillars of 50 nm, 75 nm, and 100 nm size of superior quality on p+-Si by our transfer protocol. Third, the fabricated nanodevices are also characterized electrically by conductive AFM. Fourth, the results are compared to probe station measurements on identically processed, i.e., transfer-printed μm-MOS-structures including a systematic investigation of the oxide formation. The jV-characteristics of these MOS-junctions demonstrate the electrical functionality as plasma-grown tunneling oxides and the effectivity of the transfer-printing process for their large-scale fabrication. Next, our findings are supported by fits to the jV-curves of the plasma-grown titanium oxide by kinetic-Monte-Carlo simulations. These fits allowed us to determine the dominant conduction mechanisms, the material parameters of the oxides and, in particular, a calibration of the thickness depending on applied plasma time and power. Finally, also a relative dielectric permittivity of 12 was found for such plasma-grown TiOx-layers.