bluuebunny/crossref_metadata_2025 huggingface dataset:
Impacts of oxo interactions within actinyl metal organic materials: highlight on thermal expansion behaviour
Authors: Payne Maurice K. , Pyrch Mikaela M. , Jubinsky Matthew , Basile Madeline C. , Forbes Tori Z.
Published: August 2018

Interactions between H-donors and U(vi) and Np(v) oxo groups impact the thermal expansion properties of materials.
Triphenylamine derived titanium oxo clusters: an approach to effective organic–inorganic hybrid dyes for photoactive electrodes
Authors: Zou Dan-Hong , Cui Li-Na , Liu Pei-Yi , Yang Shen , Zhu Qin-Yu , Dai Jie
Published: August 2018

Titanium oxo clusters (TOCs) anchored with photoactive triphenylamine dyes are reported for the first time. They are unusual TOCs modified with real applied dyes. Using these TPA dye pre-anchored TOCs as organic–inorganic hybrid dyes has advantages for DSSC applications.
MnO2 nanoarrays: an efficient catalyst electrode for nitrite electroreduction toward sensing and NH3 synthesis applications
Authors: Wang Rui , Wang Zao , Xiang Xiaojiao , Zhang Rong , Shi Xifeng , Sun Xuping
Published: August 2018

A MnO2 nanoarray on titanium mesh (MnO2 NA/TM) is shown to be an efficient catalyst electrode for the electroreduction of nitrite.
Phase evolution of KLaF4 nanocrystals and their effects on the photoluminescence of Nd3+ doped transparent oxyfluoride glass-ceramics
Authors: Cabral A. A. , Balda R. , Fernández J. , Gorni G. , Velázquez J. J. , Pascual L. , Durán A. , Pascual M. J.
Published: August 2018

Quantity of cubic (α-phase) and hexagonal (β-phase) KLaF4 nanocrystals (NCs) tailored by doping.
Halogen bonding at the wet interfaces of an amyloid peptide structure
Authors: Pizzi Andrea , Demitri Nicola , Terraneo Giancarlo , Metrangolo Pierangelo
Published: August 2018

Halogenation is a promising tool to stabilize – through halogen bonds – the wet interface of amyloid structures.
Revival of collective water structure and dynamics in reverse micelles brought about by protein encapsulation
Authors: Honegger Philipp , Steinhauser Othmar
Published: August 2018

A novel mechanism of depolarization in reverse micelles with zwitterionic surfactants and containing polar species but lacking ions is reported.
Enhancement of the guest orderliness in a low-symmetric perovskite-type metal–organic framework influenced by Jahn–Teller distortion
Authors: Viswanathan M.
Published: August 2018

Single-crystal neutron diffraction reveals an enhancement of the guest-orderliness in a low-symmetric MOF, with an opposite scenario for its high-symmetric cousin. The mechanism behind this unusual effect is proposed.
Absolute upconversion quantum yields of blue-emitting LiYF4:Yb3+,Tm3+ upconverting nanoparticles
Authors: Meijer Michael S. , Rojas-Gutierrez Paola A. , Busko Dmitry , Howard Ian A. , Frenzel Florian , Würth Christian , Resch-Genger Ute , Richards Bryce S. , Turshatov Andrey , Capobianco John A. , Bonnet Sylvestre
Published: August 2018

Absolute quantum yields for the individual emission bands in blue-emitting LiYF4:Yb3+,Tm3+ UCNPs are reported, measured over a broad excitation power range by three independent research centers.
Insight into the nature of M–C bonding in the lanthanide/actinide-biscarbene complexes: a theoretical perspective
Authors: Wu Qun-Yan , Cheng Zhong-Ping , Lan Jian-Hui , Wang Cong-Zhi , Chai Zhi-Fang , Gibson John K. , Shi Wei-Qun
Published: August 2018

The An/Ln–C bonding nature was explored using relativistic theory. Inclusion of Np and Pu extends understanding to later actinides bonding.
Pd nanoparticles immobilized on halloysite decorated with a cyclodextrin modified melamine-based polymer: a promising heterogeneous catalyst for hydrogenation of nitroarenes
Authors: Sadjadi Samahe , Akbari Maryam , Monflier Eric , Heravi Majid M. , Leger Bastien
Published: August 2018

For the first time, a hybrid system composed of halloysite (Hal) and a cyclodextrin modified melamine-based polymer is developed and employed for immobilization of Pd(0) nanoparticles.
Electrical and electrochemical properties of lithium solvated electron solutions derived from 1,3,5-triphenylbenzenes
Authors: Lunchev Andrey V. , Tan Kim Seng , Grimsdale Andrew C. , Yazami Rachid
Published: August 2018

Lithium solvated electron solutions based upon triphenylebenzenes have been made and their electrochemical properties were studied to assess their suitability for use as anolytes in novel batteries.
Iodine-mediated sulfenylation of 4-hydroxycoumarins with sulfonyl hydrazides under aqueous conditions
Authors: Yang Zan , Yan Yueqiao , Li An , Liao Jiashu , Zhang Lei , Yang Tao , Zhou Congshan
Published: August 2018

An efficient, metal-free approach to the synthesis of sulfenylated coumarins based on the iodine catalyzed regioselective sulfenylation of 4-hydroxycoumarins with arylsulfonyl hydrazides was developed under mild conditions in water.
A colorimetric paper sensor for visual detection of mercury ions constructed with dual-emission carbon dots
Authors: Wang Yifan , Yang Liang , Liu Bianhua , Yu Shaoming , Jiang Changlong
Published: August 2018

A ratiometric fluorescence nanosensor has been developed by mixing blue fluorescent carbon dots and red fluorescent carbon dots, where the blue fluorescence can be selectively quenched by Hg2+, while the red fluorescence is an internal reference.
Precise mono-Cu+ ion doping enhanced electrogenerated chemiluminescence from Cd–In–S supertetrahedral chalcogenide nanoclusters for dopamine detection
Authors: Wang Feng , Lin Jian , Wang Hongye , Yu Shansheng , Cui Xiaoqiang , Ali Asghar , Wu Tao , Liu Yang
Published: August 2018

Atomically precise Cu+ doping into the vacancy site of supertetrahedral chalcogenide nanoclusters can significantly enhance their electrogenerated chemiluminescence efficiency, and can be used for dopamine detection.
Green light excited ultrasensitive photoelectrochemical biosensing for microRNA at a low applied potential based on the dual role of Au NPs in TiO2 nanorods/Au NPs composites
Authors: Liu Shanshan , Cao Huijuan , Wang Xiaoying , Tu Wenwen , Dai Zhihui
Published: August 2018

An ultrasensitive photoelectrochemical biosensing strategy for microRNA was designed based on the dual role of Au NPs in TiO2 nanorods/Au NPs composites.
Shape and size of non-spherical silver nanoparticles: implications for calculating nanoparticle number concentrations
Authors: Little Christopher A. , Batchelor-McAuley Christopher , Young Neil P. , Compton Richard G.
Published: August 2018

The international drive to measure accurate number concentrations of nanoparticles is impeded by the typically heterogeneous populations of non-spherical nanoparticles.
FeS2 nanosheets encapsulated in 3D porous carbon spheres for excellent Na storage in sodium-ion batteries
Authors: Wang Fengbo , Li Guangda , Meng Xiangeng , Li Yongxing , Gao Qifa , Xu Yaqia , Cui Wenfeng
Published: August 2018

FeS2 nanosheets encapsulated in porous carbon layers were prepared by a facile method, which exhibited excellent performance of Na storage.
One-pot diastereo- and enantioselective hydrosilylation–transacylation of α-acyloxy β-enamino esters
Authors: Dai Xingjie , Weng Guanglin , Yu Shuowen , Chen Hui , Zhang Jiayan , Cheng Shaobing , Xu Xiaoying , Yuan Weicheng , Wang Zhouyu , Zhang Xiaomei
Published: August 2018

Asymmetric hydrosilylation–transacylation of α-acyloxy β-enamino esters provided various α-hydroxyl-β-acylamido esters in good yields with good diastereoselectivities and enantioselectivities.
Narrow‐band interference suppression method in multichannel SAR based on beamforming technique and sparse recovery
Authors: Lin Xiaohong , Li Xianmao , Man Xin , Tian Wei
Published: August 2018

The problem of multichannel synthetic aperture radar image recovery in the presence of sidelobe narrow‐band interference (NBI) is addressed. The NBI steering matrix is accurately estimated with the interference signal received in the passive mode. A beamforming technique is then utilised to minimise the energy loss of the target echoes and suppress NBI to a satisfactory level. By establishing a linear model for the signal with interference removed, the radar image is reconstructed via sparse recovery. The experimental results demonstrate that the proposed method can both suppress NBI effectively and generate high resolution images.
8–10 Gbit/s full synthesised continuous‐half‐rate reference‐less all‐digital CDR with sub‐harmonic frequency extraction
Authors: Yu C. , Lee D. , Park H. , Jin S. , Ahn G.‐C. , Burm J.
Published: August 2018

Continuous‐rate all‐digital reference‐less clock and data recovery (CDR) circuit that utilises a sub‐harmonic extraction scheme for wide‐range frequency detection is presented. In the proposed CDR, the capture range of the frequency locked loop (FLL) is extended to the tuning range of digital controlled oscillator, thanks to the subharmonic extraction scheme. The frequency errors of FLL in lock state are within the tracking range of CDR loop. The prototype reference‐less all‐digital CDR, fabricated using a 40 nm CMOS technology, successfully detects 8–10 Gbit/s PRBS 231 − 1 data and produces the recovered clock. The CDR consumes 29 mW from a supply voltage of 1 V for 10 Gbit/s input data. The measured RMS jitter of the recovered clock is 2.24 ps.
Impact of vector sensor on underwater acoustic communications system
Authors: Fauziya Farheen , Lall Brejesh , Agrawal Monika
Published: August 2018

The use of vector sensors as receivers for underwater acoustic communications systems is gaining popularity. It has become important to obtain performance measures for such communication systems to quantify their efficacy. The fundamental advantage of using a vector sensor as a receiver is that a single sensor is able to provide diversity gains offered by multiple input, multiple output systems. In a recent work, a novel framework for evaluating capacity of underwater channel was proposed. The approach is based on modelling the channel as a set of paths along which the signal arrives at the receiver with different angles of arrival. Here, the authors build on that framework to provide a bound on the achievable capacity of such a system. The analytical bounds have been compared against simulation results for a vector sensor‐based single input, multiple output underwater communications system. The channel parameters are modelled by analysing the statistics generated with Bellhop simulation tool. This representation of the channel is flexible and allows for characterising channels at different geographical locations and at different time instances. This characterisation in terms of channel parameters enables the computing of the performance measure (channel capacity bound) for different geographical locations.
A hydrodynamic mechanism of meteor ablation
Authors: Girin Oleksandr G.
Published: August 2018

Aims. We aim to obtain an approximate analytical solution to the equations of meteoroid dynamics within the frames of the suggested mechanism of ablation due to meteoroid melt spraying.

Methods. We have described the droplet breakaway of the melt in terms of hydrodynamic instability theory for the case of a shallow angle of meteoroid entry. The differential equation of meteoroid spraying was derived, together with the equation for the distribution function of sprayed particles by sizes. The latter was obtained considering two different frameworks for meteoroid motion law: empirical and theoretical.

Results. The trinal problem of an ablating meteoroid is solved analytically. The approximate solution is found for the system of equations of motion, ablation and number of sprayed droplets. The latter yields the equation for the distribution function of breakaway droplets by sizes, for which the approximate solution is obtained by providing the intermediate and final number distributions. The meteoroid ablation–deceleration balance remains in the regime of dynamic ablation, when the meteoroid velocity deficit due to aerodynamic drag is negligible until the instant of almost total meteoroid destruction. The responsible “h”-criterion is found, which depends only on the physical properties of the media, so that for melts of materials with lower viscosity such as iron the balance is closer to dynamic ablation than for the stony melt. The differential equation for meteoroid spraying is derived and integrated, showing a near-linear decrease of the meteoroid radius with time.

Conclusions. The proposed spraying model allows us to obtain approximate laws of meteoroid dynamics, which can serve as a base of a comprehensive study of meteor formation and evolution. The model provides intermediate and final number distributions of the breakaway droplets by sizes through direct numerical integration of the governing equations, or, alternatively, in the form of approximate relationships. The theory can be extended to the general case of a molten meteoroid entering atmosphere at an arbitrary angle.
Extra-articular Hip Impingement: Anterior Inferior Iliac Spine/Subspine Impingement, Ischiofemoral, and Anterior and Lateral Greater Trochanteric-Pelvic Impingement
Authors: Zaltz Ira , Larson Christopher
Published: August 2018

Although femoroacetabular impingement (FAI) is traditionally considered an intra-articular phenomenon, the result of abutment between the femoral head and/or neck and the acetabular rim, there are unique and relatively uncommon patterns of pathologic extra-articular hip impingement that can mimic the clinical presentation and clinical findings of traditional FAI. Anterior inferior iliac spine (AIIS) or “subspine” impingement may occur as a consequence of an abnormally anterior or distal prominence of the AIIS that may be developmental, posttraumatic, or the result of high range of motion (ROM) activities. This type of impingement can crush the capsule, labrum, and rectus femoris between the AIIS and distal femoral neck in straight hip flexion. Greater trochanteric/pelvic impingement is quite complex and can be further divided into three unique anatomic patterns. Anterior greater trochanteric–pelvic impingement is the result of impingement between the anterior hip soft tissue structures or the anterior facet/greater trochanter and anterolateral rim/lateral AIIS and pelvis when the hip is flexed, internally rotated, and abducted. This can occur in association with a prominent greater trochanter, short femoral neck, relative femoral retrotorsion, and high ROM activities. Lateral greater trochanteric–pelvic impingement is the result of impingement between an abnormally prominent or a high riding greater trochanter with a short femoral neck and the lateral pelvis when the hip is abducted. This type of impingement is characteristic of a Perthes-like hip and, in extreme cases, can be associated with severe leg length discrepancy (and abductor muscle dysfunction). Posterior greater trochanteric–pelvic/ischiofemoral impingement is the result of impingement of the quadratus femoris and/or proximal hamstring tendons between the lesser trochanter or posterior proximal femur and intertrochanteric line and the ischial tuberosity when the hip is extended and external rotated (ER). This can occur in association with deformities of the ischial tuberosity caused by prior avulsion fractures, lesser trochanteric overgrowth, extreme coxa valga, femoral antetorsion, complex proximal femoral developmental deformities, and activities requiring high degrees of extension and external rotation. A thorough understanding of these unique patterns of impingement, their clinical presentations, and complex treatment options can help in optimizing outcomes and minimizing complications in this very challenging patient population.
Ist die subkutane Immuntherapie (SCIT) Schnee von gestern?
Authors: Kopp M. V.
Published: August 2018

Auf der Suche nach aktuellen Daten zur Wirksamkeit der spezifischen Immuntherapie bei allergischer Rhinitis oder Asthma bronchiale im Kindes- und Jugendalter stößt man fast ausschließlich auf Studien, welche die sublinguale Applikationsform (SLIT) untersucht haben. Arbeiten zur subkutanen Applikationsform (SCIT) finden sich nur in geringer Zahl. Ist die SCIT aufgrund fehlender Evidenz damit Schnee von gestern? Bei indirekten Vergleichen zur Wirksamkeit beider Therapieformen schneidet die SCIT eher besser ab als die SLIT. Zudem bestehen Unsicherheiten über eine ausreichende Adhärenz und Compliance bei der SLIT im Kindes- und Jugendalter. Das Dilemma zwischen einer rein evidenzgetriebenen Betrachtungsweise und dem über Jahrzehnte bewährten Therapieprinzip der SCIT lässt sich womöglich nur lösen, indem für die spezifische Immuntherapie im Kindes- und Jugendalter separate Leitlinien formuliert werden.
Therapie des schweren Asthmas im Kindesalter
Authors: Wetzke M.
Published: August 2018

Der Anteil von Patienten mit schwerem Asthma wird auf <5 % aller Kinder und Jugendlichen mit Asthma bronchiale geschätzt. Bei ihnen besteht trotz hochdosierter Therapie keine oder nur unzureichende Kontrolle über die Erkrankung, was mit einer signifikanten Morbidität und Einschränkung der Lebensqualität assoziiert ist und einen Risikofaktor für die Entwicklung einer chronisch obstruktiven Lungenerkrankung im späteren Lebensalter darstellt. Eine strukturierte, multidisziplinäre Evaluation der Patienten sollte zunächst die Diagnose Asthma bestätigen und eine angemessene Therapieadhärenz sichern. Des Weiteren sollten mögliche Komorbiditäten und aggravierende Faktoren identifiziert und ggf. behandelt bzw. eliminiert werden. Wird unter gesicherter Kombinationstherapie aus ICD und LABA und/oder LTRA keine Erkrankungskontrolle erreicht, steht Patienten mit allergischem Asthma Omalizumab als Therapieoption zur Verfügung. Jüngst wurde zudem Tiotropium als langwirksames Anticholinergikum zugelassen. Eine Dauertherapie mit systemischen Steroiden sollte vermieden werden. In Zukunft werden personalisierte Therapieansätze mit Biologika (z. B. anti- IL-5) die Behandlungsoptionen bei schwerem Asthma ergänzen.
Efficient production of strong magnetic fields from ultraintense ultrashort laser pulse with capacitor-coil target
Authors: Wang Weiwu , Cai Hongbo , Teng Jian , Chen Jia , He Shukai , Shan Lianqiang , Lu Feng , Wu Yuchi , Zhang Bo , Hong Wei , Bi Bi , Zhang Feng , Liu Dongxiao , Xue Feibiao , Li Boyuan , Liu Hongjie , He Wu , Jiao Jinlong , Dong Kegong , Zhang Faqiang , He Yingling , Cui Bo , Xie Na , Yuan Zongqiang , Tian Chao , Wang Xiaodong , Zhou Kainan , Deng Zhigang , Zhang Zhimeng , Zhou Weimin , Cao Leifeng , Zhang Baohan , Zhu Shaoping , He Xiantu , Gu Yuqiu
Published: August 2018

An ultraintense femtosecond laser pulse was used, for the first time, to produce a strong magnetic field with controlled shapes by interactions with a capacitor-coil target with high efficiency. The temporal evolution of the strong magnetic field was obtained by the time-gated proton radiography method. A comparison of high-resolution radiographic images of proton deflection and particle-track simulations indicates a peak magnetic field of ∼20 T. The energy conversion efficiency from the ultraintense laser pulse to the magnetic field is as high as ∼10%. A simple model of the ultraintense laser-driven capacitor-coil target gives a relationship between the magnetic field strength and the electron temperature produced by the laser. Our results indicate that magnetic fields of tens of tesla could be stably produced by most of the existing ultraintense laser facilities. It potentially opens new frontiers in basic physics which require strong magnetic field environments.
Remarks on Legendrian self-linking
Authors: Beasley Chris , McLellan Brendan , Zhang Ruoran
Published: August 2018

The Thurston-Bennequin invariant provides one notion of self-linking for any homologically trivial Legendrian curve in a contact three-manifold. Here we discuss related analytic notions of self-linking for Legendrian knots in R3. Our definition is based upon reformulation of the elementary Gauss linking integral and is motivated by ideas from supersymmetric gauge theory. We recover the Thurston-Bennequin invariant as a special case.
Generalized uncertainty principle and the asymmetrical spinless Salpeter Coulomb problem
Authors: Chargui Y. , Dhahbi A.
Published: August 2018

The notion of minimal length is a common feature of various frameworks which aim to unify quantum mechanics with general relativity. As a consequence, a new generalized uncertainty principle has been proposed to replace the standard Heisenberg principle and this is likely to affect all quantum systems. In this paper, we study the effects of a minimal length on the quantum system of two different particles interacting via a Coulomb-type potential and described by the asymmetrical spinless Salpeter equation. We use the momentum representation to derive the exact energy equation for bound-states and work out the associated wave functions. In particular, we find that the minimal length regularizes the singularity of the problem at the position origin.
On the thermodynamic limit of form factor expansions of dynamical correlation functions in the massless regime of the XXZ spin 1/2 chain
Authors: Kozlowski Karol K.
Published: August 2018

This work constructs a well-defined and operational form factor expansion in a model having a massless spectrum of excitations. More precisely, the dynamic two-point functions in the massless regime of the XXZ spin-1/2 chain are expressed in terms of a properly regularised series of multiple integrals. These series are obtained by taking, in an appropriate way, the thermodynamic limit of the finite volume form factor expansions. The series are structured in a way allowing one to identify directly the contributions to the correlator stemming from the conformal-type excitations on the Fermi surface and those issuing from the massive excitations (deep holes, particles, and bound states). The obtained form factor series opens up the possibility of a systematic and exact study of asymptotic regimes of dynamical correlation functions in the massless regime of the XXZ spin 1/2 chain. Furthermore, the assumptions on the microscopic structure of the model’s Hilbert space that are necessary so as to write down the series appear to be compatible with any model—not necessarily integrable—belonging to the Luttinger liquid universality class. Thus, the present analysis also provides the phenomenological structure of form factor expansions in massless models belonging to this universality class.
Generation of a long uniform low-temperature RF discharge in helium up to atmospheric pressure
Authors: Boisvert J.-S. , Vidal F. , Margot J.
Published: August 2018

A long uniform low-temperature discharge is achieved inside a 1 mm radius fused silica tube using plane parallel linear electrodes. At a driving frequency of 13.56 MHz, a pure helium discharge is generated from 10 Torr to atmospheric pressure without any gas flow. Depending on the applied power and pressure, the discharge occurs either in the Ω or in the γ mode. As long as the gas flow is zero, the discharge shows no gradient along the electrodes. Consequently, the length of the discharge is only limited by the axial dimension of the electrodes. As the pressure increases, the Ω to γ transition occurs at higher and higher power densities. The breakdown voltage is minimum at 75 Torr with a power density down to 0.1 W cm−3. However, below 20 Torr, charged particle losses become very important so that the breakdown and maintaining voltages increase drastically. Regardless of the pressure, the gas temperature is found to always lie between 300 and 520 K.
Propagation of surface plasmon polaritons in monolayer graphene surrounded by nonlinear dielectric media
Authors: Baher S. , Lorestaniweiss Z.
Published: August 2018

The propagation of s-polarized surface plasmon polaritons (SPPs) was investigated in a monolayer graphene sheet surrounded by two dielectric media on each side, so that one or both sides of the media were linear or nonlinear with Kerr-type nonlinearity. The plasmonic properties including the wave propagation index neff, the penetration depth, the time-averaged power flow and the spatial profile of electric and magnetic fields were calculated for the following structures: Linear medium/Graphene/Linear medium (L/G/L), Nonlinear medium/G/L (NL/G/L) and NL/G/NL. The analysis of the nonlinear coefficient effect on the SPP properties showed that increasing the nonlinearity in NL/G/L enhanced neff. However, for a smaller difference between the nonlinearity of layers, neff decreased in NL/G/NL. By comparing between the proposed structures, it was found that while large values of neff can be obtained from L/G/L, its frequency confinement is smaller than that of NL/G/L and NL/G/NL. Furthermore, NL/G/L and NL/G/NL were able to support localized nonlinear modes, leading to enhanced frequency confinement of transverse electric (TE) waves in the presence of nonlinearity. Increasing the nonlinearity in NL/G/L confined the spatial profile of the electric field near the graphene interface, indicating the existence of surface plasmon solitons. The influence of the graphene chemical potential μ on the plasmonic properties of the structures was also investigated. In this case, it was found that the plasmonic properties can be controlled by μ. Our calculations may solve the difficulties in TE surface plasmons for application in optics and plasmonics.
A four-field gyrofluid model with neoclassical effects for the study of the rotation velocity of magnetic islands in tokamaks
Authors: Casolari A.
Published: August 2018

A four-field system of equations which includes the neoclassical flow damping effects and the lowest-order finite-Larmor-radius (FLR) corrections is deduced from a system of gyrofluid equations. The FLR corrections to the poloidal flow damping are calculated by solving a simplified version of the gyrokinetic equation. This system of equations is applied to the study of a chain of freely rotating magnetic islands in a tokamak, resulting from the nonlinear evolution of a resistive tearing mode, to determine the island rotation velocity consistently with the fields' radial profiles close to the resonant surface. The island rotation velocity is determined by imposing the torque balance condition. The equations thus deduced are applied to the study of two different collisionality regimes, namely the weak-damping regime and the intermediate-damping regime. The equations reduce, in the weak-damping regime, to a form already obtained in previous works, while an additional term, containing the lowest order FLR corrections to the poloidal flow damping, appears in the intermediate-damping regime. The numerical integration of the final system of equations allows the determination of the dependence of the island rotation velocity on the plasma collisionality and the island width compared to the ion Larmor radius. The results show that, in the intermediate-damping regime, the island rotation velocity is almost completely determined by the neoclassical effects, with the island width playing a minor role. The parameter ηi=Ln/LT, where Ln and LT are the density and temperature gradient length scales, plays an important role in determining the island rotation velocity.
Infrared spectroscopy of jet-cooled HCCl singlet chlorocarbene diradical: CH stretching and vibrational coupling dynamics
Authors: Kortyna A. , Nesbitt D. J.
Published: August 2018

Quantum shot noise limited laser absorption methods are used to obtain first high-resolution infrared rovibrational spectra of jet cooled chlorocarbene (HCCl) diradical in a supersonic slit-jet discharge expansion spectrometer. The rotationally resolved absorption spectra of the C–H stretch ν1 fundamental are analyzed in the framework of a Watson non-rigid asymmetric rotor Hamiltonian model. Further analysis of the mid-infrared data reveals the additional presence of what has nominally been assigned as the X̃(012) combination band with one quantum of the H–C–Cl bend (ν2) and two quanta of the C–Cl stretch (2ν3). Rovibrational constants are obtained from least squares fits for each of the four excited vibrational states built on the ν1 fundamental X̃(100) and the X̃(012) combination mode for each 35Cl and 37Cl atom isotopologue. The four bands occur within a narrow spectral window, requiring detailed comparison of multiple spectral properties (e.g., rotational constant dependence on vibrational excitation, band types/transition dipole moment alignment in the body-fixed frame, etc.) to aid in the vibrational assignment. Indeed, the IR transition intensities arise from strong anharmonic mixing between the “bright” ν1 C–H stretch and “dark” X̃012 H–C–Cl bend/C–Cl stretch combination modes, resulting in nearly equal amplitudes for the zeroth order X̃(100) and X̃012 harmonic states. Finally, to aid the spectral search for HCCl in the interstellar medium, ground state two-line combination differences are combined with previous laser-induced fluorescence results to predict precision microwave transitions for HC35Cl and HC37Cl.
Lattice constant, bond-orientational order, and solid solubility of PdPt bimetallic nanoparticles
Authors: Seo Okkyun , Kim Jaemyung , Hiroi Satoshi , Song Chulho , Kumara L. S. R. , Tayal Akhil , Chen Yanna , Kobayashi Hirokazu , Kitagawa Hiroshi , Sakata Osami
Published: August 2018

Crystal structure deviations of bimetallic Pd-Pt nanoparticles (NPs) were investigated using synchrotron high-energy X-ray diffraction. The samples comprised Pd NPs and bimetallic Pd-Pt NPs featuring those with a Pd-core/Pt-shell structure as well as PdPt solid-solution NPs with varying diameters of 6.1, 6.7, 8.1, and 11.2 nm. The Rietveld method was used to find the lattice constant of the Pd NPs, which was larger than the bulk value, while reverse Monte Carlo modeling revealed that they possessed a highly disordered structure. The lattice constants of the Pd-Pt bimetallic NPs were found to vary with the Pt content. For Pd-core/Pt-shell structure NPs, the lattice constants decreased with the Pt content owing to lattice relaxation at the core/shell interface. After a reaction process of hydrogen absorption/desorption, the lattice constant of the resulting PdPt solid-solution NPs increased with the NP Pt content, which followed Vegard's law. The degree of disorder of the solid-solution NPs was evaluated by the PBOO values (i.e., structural parameters describing the deviation of the local structure from an ideal crystal structure) and was found to decrease with the Pt content. A short-range-order parameter was introduced using a three-dimensional reverse Monte Carlo configuration structure to evaluate the atomic-scale solid solubility of the Pd0.92Pt0.08 and Pd0.79Pt0.21 NPs. The parameter values obtained were close to 0, indicating that the Pd and Pt atoms were essentially randomly dispersed in the solid-solution NPs.
Nanofluidic terahertz metasensor for sensing in aqueous environment
Authors: Shih Kailing , Pitchappa Prakash , Jin Lin , Chen Chia-Hung , Singh Ranjan , Lee Chengkuo
Published: August 2018

The terahertz spectral region has received tremendous attention for label free chemical and biological sensing, due to the presence of molecular fingerprints, low energy characteristics, and remote sensing capabilities. However, a major hindrance for the realization of a high performance terahertz bio-chemical sensor comes from the large absorption of terahertz waves by aqueous solution. Here, we overcome this limitation by confining the analyte-aqueous solution in a nanovolumetric fluidic chamber, integrated on metamaterial resonant cavities. The metamaterial resonators confine electromagnetic fields in extremely subwavelength space and hence allow for the enhanced interaction between the nanovolumetric analyte-aqueous solution and terahertz waves, while minimizing the absorption loss. We compare the sensing performance of split ring resonator and Fano resonator systems as metamaterial resonators. As a demonstration of chemical sensing, three alcoholic solutions with different concentrations were measured. Selective adenosine triphosphate (ATP) sensing capability was examined through ATP aptamer functionalization on gold metamaterials, where a decrease in the transmittance value was observed as the ATP concentration increased. The proposed sensing approach has the potential to be an effective tool for molecular analysis through exploiting the advantages offered by low energy terahertz, subwavelength metamaterial resonators and nanofluidic technologies.
Cryogenic optomechanic cavity in low mechanical loss material
Authors: Bon Jérémy , Neuhaus Leonhard , Deléglise Samuel , Briant Tristan , Abbé Philippe , Cohadon Pierre-François , Galliou Serge
Published: August 2018

Mechanical losses lower than 10−9 have been demonstrated on quartz crystal acoustic cavities at liquid helium temperature. In addition, such cavities could rather easily be adapted to be used as optical cavities. This paper addresses the optomechanic devices that could merge from, while highlighting the major assets of each option and showing some preliminary results, including tests on quartz and CaF2 samples. It is shown that the mechanical displacement can be actuated optically by radiation pressure according to proper designs.
Tutorial: Organic field-effect transistors: Materials, structure and operation
Authors: Lamport Zachary A. , Haneef Hamna F. , Anand Sajant , Waldrip Matthew , Jurchescu Oana D.
Published: August 2018

Chemical versatility and compatibility with a vast array of processing techniques has led to the incorporation of organic semiconductors in various electronic and opto-electronic devices. One such device is the organic field-effect transistor (OFET). In this tutorial, we describe the structure, operation, and characterization of OFETs. Following a short historical perspective, we introduce the architectures possible for OFETs and then describe the device physics and the methods for extracting relevant device parameters. We then provide a brief overview of the myriad organic semiconductors and deposition methods that were adopted for OFETs in the past decades. Non-ideal device characteristics, including contact resistance, are then discussed along with their effects on electrical performance and on the accuracy of extracting device parameters. Finally, we highlight several measurements involving OFETs that allow access to fundamental properties of organic semiconductors and the mechanism of charge transport in these materials.
Transformations of neutral particles in the discharge plasma in inert gases with water vapor and deuterium
Authors: Bernatskiy A. V. , Kochetov I. V. , Ochkin V. N.
Published: August 2018

The chemical composition of the discharge plasma in inert gases with H2O and D2 additives is investigated experimentally and theoretically for the first time. A new approach is applied to the measurement of the concentrations of plasma-produced particles. It includes the combination of the optical multispectral actinometry technique and the concept of intermediate chemically active actinometers. The scheme of the chemical processes in the plasma is elaborated. The dynamics and steady state concentrations of near 20 atomic and molecular particles are described. The experimental data on particle densities are in good agreement with the calculated values. The data on stationary particle concentrations with a variation of H2O (106–1016) cm−3 and D2 (1012–1016) cm−3 are presented. Within these limits, the concentrations of chemically active atoms as well as 2-, 3-, and 4-atomic molecules are in the (103–9.6 × 1015) cm−3 interval. The use of the new improved technique of actinometry combined with the modeling code significantly extends the capabilities of the highly sensitive spectral emission technique for the analysis of the chemical composition of the multi-component plasma.
On the phase behaviors of hydrocarbon and noble gas clathrate hydrates: Dissociation pressures, phase diagram, occupancies, and equilibrium with aqueous solution
Authors: Tanaka Hideki , Yagasaki Takuma , Matsumoto Masakazu
Published: August 2018

We apply a statistical mechanical theory on clathrate hydrates to an exploration of the phase behaviors of hydrocarbon and noble gas clathrate hydrates. Two- and three-phase coexisting conditions in the whole space of thermodynamic variables (temperature, pressure, and composition) are evaluated only from intermolecular interactions for water and guest species. The occupancy of guest molecules in various types of cages is also calculated. We find that a small difference in the guest size gives rise to a rich variety of phase behaviors, notably for the shape of the two-phase boundary and the occupancy. Ethane clathrate hydrate is found to exhibit the most drastic and intriguing features in various properties arising from its non-stoichiometry. We investigate the phase behaviors of clathrate hydrate in terms of the partial molar quantities derived from the chemical potentials of guest and water. Our method also allows exploring the aqueous solution of an apolar guest molecule in the low temperature and high pressure regime coexisting with the corresponding clathrate hydrate for which the free guest fluid phase is substituted at high temperatures. It is shown that the temperature dependence of methane solubility in liquid water in the presence of clathrate hydrate is opposite to that being in equilibrium with the methane fluid without clathrate hydrate. This phenomenon is elucidated by a substantial decrease in the chemical potential of methane from the hydrate/guest boundary to the hydrate/water.
Mitigating laser-imprint effects in direct-drive inertial confinement fusion implosions with an above-critical-density foam layer
Authors: Hu S. X. , Theobald W. , Radha P. B. , Peebles J. L. , Regan S. P. , Nikroo A. , Bonino M. J. , Harding D. R. , Goncharov V. N. , Petta N. , Sangster T. C. , Campbell E. M.
Published: August 2018

Low-density foams of low-/mid-Z materials have been previously proposed to mitigate laser imprint for direct-drive inertial confinement fusion (ICF). For foam densities above the critical density of the drive laser, the mechanism of laser-imprint mitigation relies on the reduced growth rate of Rayleigh–Taylor instability because of the increased ablation velocity and density scale length at the ablation surface. Experimental demonstration of this concept has been limited so far to planar-target geometry. The impact of foams on spherical implosions has not yet been explored in experiments. To examine the viability of using an above-critical-density foam layer to mitigate laser-imprint effects in direct-drive ICF implosions on OMEGA, we have performed a series of 2-D DRACO simulations with state-of-the-art physics models, including nonlocal thermal transport, cross-beam energy transfer, and first-principles equation-of-state tables. The simulation results indicate that a 40-μm-thick CH or SiO2 foam layer with a density of ρ = 40 mg/cm3 added to a D2-filled polystyrene (CH) capsule can significantly improve the moderate-adiabat (α ≈ 3) implosion performance. In comparison to the standard CH target implosion, an increase in neutron yield by a factor of 4 to 8 and the recovery of 1-D compression ρR are predicted by DRACO simulations for a foam-target surface roughness of σrms ≤ 0.5 μm. These encouraging results could readily facilitate experimental demonstrations of laser-imprint mitigation with an above-critical-density foam layer.
The origin of holomorphic states in Landau levels from non-commutative geometry and a new formula for their overlaps on the torus
Authors: Haldane F. D. M.
Published: August 2018

Holomorphic functions that characterize states in a two-dimensional Landau level have been central to key developments such as the Laughlin state. Their origin has historically been attributed to a special property of “Schrödinger wavefunctions” of states in the “lowest Landau level.” It is shown here that they instead arise in any Landau level as a generic mathematical property of the Heisenberg description of the non-commutative geometry of guiding centers. When quasiperiodic boundary conditions are applied to compactify the system on a torus, a new formula for the overlap between holomorphic states, in the form of a discrete sum rather than an integral, is obtained. The new formula is unexpected from the previous “lowest-Landau level Schrödinger wavefunction” interpretation.
GaSb-based diode lasers with asymmetric coupled quantum wells
Authors: Jiang Jiang , Shterengas Leon , Hosoda Takashi , Belyanin Alexei , Kipshidze Gela , Belenky Gregory
Published: August 2018

Asymmetric tunnel coupled quantum wells with built-in resonant second order nonlinearity were designed and fabricated within the antimonide material system. The quantum wells demonstrated intensive photo- and electroluminescence responses associated with optical transitions between two tunnel-split conduction band subbands and one valence band subband. The thickness of the tunnel barrier defined the optical gain bandwidth and resonance energy for the difference frequency generation. The test diode lasers based on asymmetric quantum wells with a conduction subband splitting of about 25 meV operated near 2.1 μm at room temperature and demonstrated high differential gain and excellent performance parameters. The experimental modal gain spectra showed relatively flat top and an extended bandwidth at high pumping levels.
L-Carnitine improves endocrine function and folliculogenesis by reducing inflammation, oxidative stress and apoptosis in mice following induction of polycystic ovary syndrome
Authors: Kalhori Zahra , Mehranjani Malek Soleimani , Azadbakht Mehri , Shariatzadeh Mohammad Ali
Published: August 2018

Polycystic ovary syndrome (PCOS) is related to low levels of serum l-carnitine, which has antioxidant, anti-inflammatory and antiapoptotic properties. The aim of this study was to investigate the effect of l-carnitine on folliculogenesis in mice following induction of PCOS. PCOS was induced by daily injections of testosterone enanthate (1mg per 100g, s.c., for 35 days). NMRI mice (21 days old) were divided into four groups (n=6 per group): Control, Control+l-carnitine, PCOS and PCOS+l-carnitine. Mice were treated with 500mgkg−1, i.p., l-carnitine every second day for 28 days. Ovaries were studied stereologically and serum concentrations of FSH, LH, testosterone, interleukin (IL)-6 and tumour necrosis factor (TNF)-α were determined using ELISA kits. Serum concentrations of malondialdehyde (MDA) and the ferric ion reducing antioxidant power (FRAP) were also analysed. Apoptosis of follicles was evaluated by terminal deoxyribonucleotidyl transferase-mediated dUTP–digoxigenin nick end-labelling (TUNEL). CD31 was assessed immunohistochemically. Data were analysed using one-way analysis of variance (ANOVA) and Tukey’s test, differences considered significant at P<0.05.The total volume of the ovary, cortex volume, oocyte volume, zona pellucida thickness and the number of antral follicles increased significantly, whereas the number of primary and preantral follicles decreased significantly, in the PCOS+l-carnitine versus PCOS group. In the PCOS+l-carnitine group, serum concentrations of FSH and FRAP increased significantly, whereas there were significant decreases in serum concentrations of testosterone, LH, MDA, IL-6 and TNF-α, as well as in the percentage of TUNEL-positive apoptotic cells, compared with the PCOS group. l-Carnitine improves folliculogenesis and is therefore suggested as a therapeutic supplement in the treatment of PCOS.
Wettability in complex porous materials, the mixed-wet state, and its relationship to surface roughness
Authors: AlRatrout Ahmed , Blunt Martin J. , Bijeljic Branko
Published: August 2018

Significance

In many important processes that control

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storage in aquifers, oil recovery, and gas exchange in leaves, for instance, flow is controlled by the interaction of immiscible fluids with a rough surface. We use micrometer-resolution X-ray imaging to look inside millimeter-sized porous structures, obtaining millions of measurements of contact angle and interfacial curvature. We quantify the relationship between surface roughness and wettability. Rougher surfaces are associated with lower contact angles and higher interfacial curvatures. We identify a distinct mixed-wet state where two fluid phases remain connected over a wide range of saturation. This state can be designed to improve oil recovery or the performance of fuel cells, catalysts, and other porous materials.
Characteristics of sports participation and psychosocial health in children: Results of a cross‐sectional study
Authors: Moeijes Janet , Van Busschbach Jooske T. , Lockhart Krista L. , Bosscher Ruud J. , Twisk Jos W. R.
Published: August 2018

Several studies suggest that sports participation is beneficial for psychosocial health. There is, however, only a limited number of studies about the relationship of specific characteristics of sports participation with psychosocial health. The present study investigated associations between characteristics of sports participation and three aspects of psychosocial health, i.e. internalising problems, externalising problems and prosocial behaviour. The examined characteristics of sports participation pertained to individual versus team sports, indoor versus outdoor sports, involvement in competition or not, and contact sports versus non‐contact sports. Cross‐sectional data were collected from 1768 Dutch children aged 10–12 years who were member of a sports club. These children completed the Movement and Sports Monitor Questionnaire Youth aged 8–12 years (MSMQ) and the Strength and Difficulties Questionnaire (SDQ). Linear multilevel analyses and logistic generalised estimating equation were conducted. Children participating in team sports, outdoor sports, or competition showed fewer internalising problems than children engaged in individual sports, indoor sports, or only training. The associations with internalising problems were stronger for boys than for girls. Children participating in non‐contact sports showed fewer externalising problems than children performing non‐contact sports as well as contact sports. Children practising indoor sports or non‐contact sports showed better prosocial behaviour than children doing outdoor or contact sports. In conclusion, the form of sports participation seemed to matter highly with respect to internalising problems, especially for boys, and, to a lesser extent, with respect to externalising problems and prosocial behaviour. This offers starting points for developing tailor‐made sports programmes for children.
Food Insecurity and Terrorism
Authors: Adelaja Adesoji , George Justin , Miyahara Takashi , Penar Eva
Published: August 2018

This article investigates the relationship between food insecurity and terrorism for a cross country panel sample. Using an instrumental variable approach, we empirically find that greater food availability is associated with greater incidence of terrorism, but better food access is associated with reduced terrorism activities. The relationship is robust across alternate estimators and terrorism measures. By providing additional insights on the effects of specific food insecurity dimensions on terrorism, our findings support the growing number of policies and efforts to enhance global security through food security.