bluuebunny/crossref_metadata_2025 huggingface dataset:
The Bronchus First and Vessels Simultaneously Stapled Technique: A Safe and Simple Method for Video-Assisted Right Upper Lobe Lobectomy
Authors: Xu Hao , Zhang Linyou
Published: January 2018

Objective Video-assisted thoracic surgery lobectomy is a minimally invasive procedure for major pulmonary resection. The purpose of this study was to present a novel approach with a thoracoscope in the right upper lobe and to compare different lobectomy methods at our institution.

Methods We reviewed the medical records of patients who underwent a thoracoscopic right upper lobectomy for lung cancer between September 2015 and September 2016. We performed 128 thoracoscopic right upper lobectomies: group A (n = 50) was treated with the bronchus-first and vessels simultaneously stapled method and group B (n = 78) was treated with the conventional isolation–ligation method. Preoperative mediastinal staging and lymphadenectomy followed the National Comprehensive Cancer Network guidelines. The intra- and postoperative outcomes were recorded and statistically compared.

Results All patients underwent successful thoracoscopic right upper lobectomies. No significant differences in mean intraoperative blood loss, massive hemorrhage (>500 mL), and postoperative complications were observed between the two groups (p < 0.05). The mean operative time of group A was less than that of group B (110.80 ± 34.74 versus 167.01 ± 48.38 minutes, p = 0.000). The mean duration of chest drainage in group A was 4.34 ± 2.06 days, which was shorter than that of group B (5.85 ± 3.13 days, p = 0.017). No significant differences were observed in the local recurrence and distant recurrence between the two groups during the postoperative follow-up.

Conclusions Thoracoscopic right upper lobectomy with the lobectomy bronchus-first and vessels simultaneously stapled method is a safe and efficient procedure that leads to better recovery.
Long-Term Skeletal Outcomes of Primary Hyperparathyroidism Patients After Treatment with Parathyroidectomy: A Systematic Review and Meta-Analysis
Authors: Zhang Lu , Liu Xiaomei , Li Hongwei
Published: January 2018

The aim of the study was to assess and define the association between parathyroidectomy (PTX) and long-term skeletal outcomes in primary hyperparathyroidism (PHPT) patients. PubMed, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials were systematically searched up to June 31, 2017, without language restriction. Any study comparing skeletal outcomes [fracture risk or bone mineral density (BMD)] of PHPT patients after more than 12 months of PTX treatment versus non-PTX treatment was included. Pooled relative risks or odds ratios with 95% confidence intervals and weighted mean difference were calculated using random-effects models irrespective of statistical heterogeneity assessed by I2 statistic. Finally, 5 randomized controlled trials (RCTs, n=584) and 10 cohort studies (CSs, n=12202) were included. CSs suggest PTX treatment versus non-PTX treatment is significantly associated with 36% reduction in the risk of fracture, with no heterogeneity, and an increase in the lumbar spine change by 0.55 WMD, with no heterogeneity. RCTs indicate PTX treatment versus non-PTX treatment is significantly associated with BMD change of 0.97 WMD at the lumbar spine with substantial heterogeneity, and 1.23 WMD at the femoral neck with no heterogeneity. The existing CSs indicate PTX-treatment versus non-PTX-treatment might reduce the risk of fracture in PHPT patients. The existing RCTs do not provide sufficient or precise evidence that PTX-treatment affects the fracture risk of PHPT patients, but offer data that subsets of patients who could potentially benefit from PTX-treatment can be identified.
Improving battery lifetime and reducing life cycle cost of a PV/battery system using supercapacitor for remote agricultural farm power application
Authors: Ayodele T. R. , Ogunjuyigbe A. S. O. , Olateju B. E.
Published: January 2018

One of the challenges in utilizing photovoltaic systems in agricultural applications is the cost of batteries. Batteries are often replaced when used for farm power compared to residential applications due to the incessant high current that is drawn from the battery as a result of the nature of operation in agricultural applications. This increases the overall life cycle cost (LCC) of the system, which makes generation of electricity from renewable energy sources unattractive. This paper proposes the use of supercapacitors (SCs) to improve the battery lifetime and reduce the life cycle cost of a standalone Photovotaic (PV)/battery system for a remote farm power application. Two scenarios are created: PV/battery system only (i.e., without SC) and PV/battery/SC (i.e., with SC) for a typical remote agricultural feedmill. The sizes of PV, battery, and SC are optimally matched with the load profile of the feedmill using genetic algorithm, while the battery lifetime was estimated based on Schiffer's technique. The analysis is carried out through simulation in the Matlab™ environment. Some of the key results reveal that PV/battery only has a slightly lower initial capital cost of $5010 compared to PV/battery/SC with an initial capital cost of $5480. However, the battery lifetimes with and without the use of SC are 5 and 2 years, respectively, denoting an improvement of 40% in the battery lifetime when SC is adopted. The LCC values of the PV/battery system with and without SC are obtained to be $6423 and $11 037, respectively, indicating a significant reduction of 58% in the LCC when SC is utilized.
Centrifugal particle confinement in mirror geometry
Authors: White Roscoe , Hassam Adil , Brizard Alain
Published: January 2018

The use of supersonic rotation of a plasma in mirror geometry has distinct advantages for thermonuclear fusion. The device is steady state, there are no disruptions, the loss cone is almost closed, sheared rotation stabilizes magnetohydrodynamic instabilities as well as plasma turbulence, there are no runaway electrons, and the coil configuration is simple. In this work, we examine the effect of rotation on mirror confinement using a full cyclotron orbit code. The full cyclotron simulations give a much more complete description of the particle energy distribution and losses than the use of guiding center equations. Both collisionless loss as a function of rotation and the effect of collisions are investigated. Although the cross field diffusion is classical, we find that the local rotating Maxwellian is increased to higher energy, increasing the fusion rate and also enhancing the radial diffusion. We find a loss channel not envisioned with a guiding center treatment, but a design can be chosen that can satisfy the Lawson criterion for ions. Of course, the rotation has a minimal effect on the alpha particle birth distribution, so there is initially loss through the usual loss cone, just as in a mirror with no rotation. However after this loss, the alphas slow down on the electrons with little pitch angle scattering until reaching low energy, so over half of the initial alpha energy is transferred to the electrons. The important problem of energy confinement, with losses primarily through the electron channel, is not addressed in this work. We also discuss the use of rotating mirror geometry to produce an ion thruster.
The influence of the N(2D) and N(2P) states in the ionization of the pink afterglow of the nitrogen flowing DC discharge
Authors: Levaton J. , Klein A. N. , Binder C.
Published: January 2018

In the present work, we extensively discuss the role of N(2D) and N(2P) atoms in the ionization processes of pink afterglow based on optical emission spectroscopy analysis and kinetic numerical modelling. We studied the pink afterglow generated by a nitrogen DC discharge operating at 0.6 Slm−1 flow rate, 45 mA discharge current and pressures ranging from 250 to 1050 Pa. The 391.4 nm nitrogen band was monitored along the afterglow furnishing the relative density of the N2+(B2Σ+u, v = 0) state. A numerical model developed to calculate the nitrogen species densities in the afterglow fits the excited ion density profiles well for the experimental conditions. From the modelling results, we determine the densities of the N+, N2+, N3+, and N4+ ions; the calculations show that the N3+ ion density predominates in the afterglow at the typical residence times of the pink afterglow. This behaviour has been observed experimentally and reported in the literature. Furthermore, we calculate the fractional contribution in the ionization for several physical-chemical mechanisms in the post-discharge. Even with the N3+ ion density being dominant in the afterglow, we find through the calculations that the ionization is dominated by the reactions N(2D) + N(2P) → N2+(X2Σ+g) + e and N2(a′1Σ−u) + N2(X 1Σg+, v > 24) → N4+ + e. The ion conversion mechanisms, or ion transfer reactions, which are responsible for the fact that the N3+ density dominates in the post-discharge, are investigated.
Mode-locking in advection-reaction-diffusion systems: An invariant manifold perspective
Authors: Locke Rory A. , Mahoney John R. , Mitchell Kevin A.
Published: January 2018

Fronts propagating in two-dimensional advection-reaction-diffusion systems exhibit a rich topological structure. When the underlying fluid flow is periodic in space and time, the reaction front can lock to the driving frequency. We explain this mode-locking phenomenon using the so-called burning invariant manifolds (BIMs). In fact, the mode-locked profile is delineated by a BIM attached to a relative periodic orbit (RPO) of the front element dynamics. Changes in the type (and loss) of mode-locking can be understood in terms of local and global bifurcations of the RPOs and their BIMs. We illustrate these concepts numerically using a chain of alternating vortices in a channel geometry.
Effects of strain energy on the recrystallization within narrow metallization
Authors: Murray Conal E.
Published: January 2018

Elastic strain energy within materials due to recrystallization of grains with a specific orientation, or texture, can be calculated through the use of Eshelby inclusions, where a recrystallized grain can be treated as an elastically anisotropic inclusion in an elastically isotropic matrix. The evolution of texture that minimizes elastic strain energy is shown to be dependent on the specific strain state. The interaction strains generated by this elastic incompatibility and corresponding strain energy have been derived for grains with cubic symmetry for general forms of the applied strain tensor. For uniaxial and isotropic, biaxial strain tensors, the interaction strain tensor and corresponding elastic strain energy density are proportional to the orientation parameter, Γ, which relates the Miller indices of the recrystallized grain to the loading direction: either parallel to the uniaxial strain direction or perpendicular to the plane in which isotropic biaxial strain is applied. It is rigorously proven that for elastically isotropic inclusions, corresponding to Γ = 1/5, the interaction strain is zero. Although blanket films often possess an isotropic, biaxial stress state, metallization trenches can exhibit a combination of normal and shear strain components, particularly near the trench corners. It is shown that in cases where shear is present, the resulting elastic strain energy can be lowered by the development of (110) texture despite its higher surface energy, as has been observed in thin films and interconnect trenches. These results suggest that shear strain can play an important role in the evolution of texture in narrow, metallization structures.
Resistive magnetohydrodynamics with toroidal rotation in toroidal plasmas
Authors: Cao Jintao , Cai Huishan
Published: January 2018

Toroidal rotation has always existed in tokamak plasmas, and its Mach number can reach unity during neutral beam injection. Toroidal rotation can affect plasma equilibrium and magnetohydrodynamic instabilities significantly. Based on linearized equations including the toroidal rotation effect, the toroidal model derived by Glasser et al. [Phys. Fluids 18, 875 (1975)] is extended to include this effect, and a set of resistive equations including the toroidal rotation effect in the axi-symmetry toroidal geometry is derived. Based on these derived equations, the effect of toroidal rotation on tearing modes is considered, and the growth rate of tearing modes is obtained analytically. It is shown that the effect of toroidal rotation on tearing modes depends on both the direction of toroidal rotation flow and the sign of toroidal rotation flow shear. When they have the same sign, they play a role in stabilizing tearing modes, while when they have opposite signs, they have a destabilizing effect on tearing modes.
First-principles study of the α-ω phase transformation in Ti and Zr coupled to slip modes
Authors: Kumar Anil , Bronkhorst Curt A. , Lookman Turab
Published: January 2018

We present first-principles density functional theory calculations to study the α-ω phase transformation in Ti and Zr and its coupling to slip modes of the two phases. We first investigate the relative energetics of all possible slip systems in the α and ω phases to predict the dominant slip system that is activated during a plastic deformation under an arbitrary load. Using this and the crystallographic orientation relationships between α and ω phases, we construct low energy α/ω interfaces and study the energetics of the slip system at the interface between α and ω to compare to the slip systems in the bulk phases. We find that for a particular crystallographic orientation relationship, where (basal)α∥(prismatic-II)ω, and [a]α∥[c]ω, the slip at the interface is preferred compared to its bulk counterparts. This implies that the plastically deformed α/ω phase with this orientation relationship prefers to retain the interface (or coexisting phases) than transforming back to the pure phase after unloading. This is consistent with the observation that the ω-phase is retained in samples loaded in flyer plate experiments or under high-pressure torsion. Furthermore, calculation of the energy barrier for α to ω phase transformation as a function of glide at the α/ω interface shows significant coupling between the α-ω phase transformation and slip modes in Ti and Zr.
Soft x-ray spectroscopy of high pressure liquid
Authors: Qiao Ruimin , Xia Yujian , Feng Xuefei , Macdougall James , Pepper John , Armitage Kevin , Borsos Jason , Knauss Kevin G. , Lee Namhey , Allézy Arnaud , Gilbert Benjamin , MacDowell Alastair A. , Liu Yi-Sheng , Glans Per-Anders , Sun Xuhui , Chao Weilun , Guo Jinghua
Published: January 2018

We describe a new experimental technique that allows for soft x-ray spectroscopy studies (∼100-1000 eV) of high pressure liquid (∼100 bars). We achieve this through a liquid cell with a 100 nm-thick Si3N4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si3N4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si3N4 membrane increases with decreasing size and more specifically is inversely proportional to the side length of the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si3N4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si3N4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (∼350 eV) of a CaCl2 aqueous solution are collected under different pressures up to 41 bars.
Hollow wall to stabilize and enhance ignition hohlraums
Authors: Vandenboomgaerde M. , Grisollet A. , Bonnefille M. , Clérouin J. , Arnault P. , Desbiens N. , Videau L.
Published: January 2018

In the context of the indirect-drive scheme of the inertial-confinement fusion, performance of the gas-filled hohlraums at the National Ignition Facility appears to be reduced. Experiments ascertain a limited efficacy of the laser beam propagation and x-ray conversion. One identified issue is the growth of the gold plasma plume (or bubble) which is generated near the ends of the hohlraum by the impact of the laser beams. This bubble impedes the laser propagation towards the equator of the hohlraum. Furthermore, for high foot or low foot laser pulses, the gold-gas interface of the bubble can be unstable. If this instability should grow to mixing, the x-ray conversion could be degraded. A novel hollow-walled hohlraum is designed, which drastically reduces the growth of the gold bubble and stabilizes the gold-gas interface. The hollow walls are built from the combination of a thin gold foil and a gold domed-wall. We theoretically explain how the bubble expansion can be delayed and the gold-gas interface stabilized. This advanced design lets the laser beams reach the waist of the hohlraum. As a result, the x-ray drive on the capsule is enhanced, and more spherical implosions are obtained. Furthermore, this design only requires intermediate gas fill density to be efficient.
Nanoscale quantification of intracellular element concentration by X-ray fluorescence microscopy combined with X-ray phase contrast nanotomography
Authors: Gramaccioni Chiara , Yang Yang , Procopio Alessandra , Pacureanu Alexandra , Bohic Sylvain , Malucelli Emil , Iotti Stefano , Farruggia Giovanna , Bukreeva Inna , Notargiacomo Andrea , Fratini Michela , Valenti Piera , Rosa Luigi , Berlutti Francesca , Cloetens Peter , Lagomarsino Stefano
Published: January 2018

We present here a correlative X-ray microscopy approach for quantitative single cell imaging of molar concentrations. By combining the elemental content provided by X-ray fluorescence microscopy and the morphology information extracted from X-ray phase nanotomography, we determine the intracellular molarity distributions. This correlative method was demonstrated on a freeze-dried human phagocytic cell to obtain the absolute elemental concentration maps of K, P, and Fe. The cell morphology results showed a very good agreement with atomic-force microscopy measurements. This work opens the way for non-destructive single cell chemical analysis down to the sub-cellular level using exclusively synchrotron radiation techniques. It will be of high interest in the case where it is difficult to access the morphology using atomic-force microscopy, for example, on frozen-hydrated cells or tissues.
Transport of oxygen ions in Er doped La2Mo2O9 oxide ion conductors: Correlation with microscopic length scales
Authors: Paul T. , Ghosh A.
Published: January 2018

We report oxygen ion transport in La2−xErxMo2O9 (0.05 ≤ x ≤ 0.25) oxide ion conductors. We have measured conductivity and dielectric spectra at different temperatures in a wide frequency range. The mean square displacement and spatial extent of non-random sub-diffusive regions are estimated from the conductivity spectra and dielectric spectra, respectively, using linear response theory. The composition dependence of the conductivity is observed to be similar to that of the spatial extent of non-random sub-diffusive regions. The behavior of the composition dependence of the mean square displacement of oxygen ions is opposite to that of the conductivity. The attempt frequency estimated from the analysis of the electric modulus agrees well with that obtained from the Raman spectra analysis. The full Rietveld refinement of X-ray diffraction data of the samples is performed to estimate the distance between different oxygen lattice sites. The results obtained from such analysis confirm the ion hopping within the spatial extent of non-random sub-diffusive regions.
Non-trivial behavior of the low temperature maximum of dielectric constant and location of the end critical point in Na0.5Bi0.5TiO3-0.06BaTiO3 lead free relaxor ferroelectrics crystals detected by acoustic emission
Authors: Dul'kin Evgeniy , Tiagunova Jenia , Mojaev Evgeny , Roth Michael
Published: January 2018

[001] lead free relaxor ferroelectrics crystals of Na0.5Bi0.5TiO3–0.06BaTiO3 were studied by means of dielectric and acoustic emission methods in the temperature range of 25–240 °C and under a dc bias electric field up to 0.4 kV/cm. A temperature maximum of the dielectric constant was found near 170 °C, as well as the acoustic emission bursts pointed out to both the depolarization temperature near 120 °C and the temperature, corresponding to the maximum of dielectric constant, near 170 °C. While the depolarization temperature increased linearly, the temperature of the dielectric constant maximum was shown to exhibit a V-shape behavior under an electric field: it initially decreases, reaches a sharp minimum at some small threshold electric field of 0.15 kV/cm, and then starts to increase similar to the Curie temperature of the normal ferroelectrics, as the field enhances. Acoustic emission bursts, accompanying the depolarization temperature, weakened with the enhancing field, whereas the ones accompanying the temperature of the dielectric constant maximum exhibited two maxima: near 0.1 kV/cm and near 0.3 kV/cm. The meaning of these two acoustic emission maxima is discussed.
A dissipative self-sustained optomechanical resonator on a silicon chip
Authors: Huang J. G. , Li Y. , Chin L. K. , Cai H. , Gu Y. D. , Karim M. F. , Wu J. H. , Chen T. N. , Yang Z. C. , Hao Y. L. , Qiu C. W. , Liu A. Q.
Published: January 2018

In this letter, we report the experimental demonstration of a dissipative self-sustained optomechanical resonator on a silicon chip by introducing dissipative optomechanical coupling between a vertically offset bus waveguide and a racetrack optical cavity. Different from conventional blue-detuning limited self-oscillation, the dissipative optomechanical resonator exhibits self-oscillation in the resonance and red detuning regime. The anti-damping effects of dissipative optomechanical coupling are validated by both numerical simulation and experimental results. The demonstration of the dissipative self-sustained optomechanical resonator with an extended working range has potential applications in optomechanical oscillation for on-chip signal modulation and processing.
Acoustic valley edge states in a graphene-like resonator system
Authors: Yang Yahui , Yang Zhaoju , Zhang Baile
Published: January 2018

The concept of valley physics, as inspired by the recent development in valleytronic materials, has been extended to acoustic crystals for manipulation of air-borne sound. Many valleytronic materials follow the model of a gapped graphene. Yet the previously demonstrated valley acoustic crystal adopted a mirror-symmetry-breaking mechanism, lacking a direct counterpart in condensed matter systems. In this paper, we investigate a two-dimensional (2D) periodic acoustic resonator system with inversion symmetry breaking, as an analogue of a gapped graphene monolayer. It demonstrates the quantum valley Hall topological phase for sound waves. Similar to a gapped graphene, gapless topological valley edge states can be found at a zigzag domain wall separating different domains with opposite valley Chern numbers, while an armchair domain wall hosts no gapless edge states. Our study offers a route to simulate novel valley phenomena predicted in gapped graphene and other 2D materials with classical acoustic waves.
Chemical ordering and crystal nucleation at the liquid surface: A comparison of Cu50Zr50 and Ni50Al50 alloys
Authors: Tang Chunguang , Harrowell Peter
Published: January 2018

We study the influence of the liquid-vapor surface on the crystallization kinetics of supercooled metal alloys. While a good glass former, Cu50Zr50, shows no evidence of surface enhancement of crystallization, Ni50Al50 exhibits an increased rate of crystallization due to heterogeneous nucleation at the free liquid surface. The difference in the compositional fluctuations at the interface is proposed as the explanation of the distinction between the two alloys. Specifically, we observe compositional ordering at the surface of Ni50Al50, while the Cu50Zr50 alloy only exhibits a diffuse adsorption of the Cu at the interface. We argue that the general difference in composition susceptibilities at planar surfaces represents an important factor in understanding the difference in the glass forming ability of the two alloys.
On the dispersion characteristics of extraordinary mode in a relativistic fully degenerate electron plasma
Authors: Noureen S. , Abbas G. , Sarfraz M.
Published: January 2018

The study of relativistic degenerate plasmas is important in many astrophysical and laboratory environments. Using linearized relativistic Vlasov–Maxwell equations, a generalized expression for the plasma conductivity tensor is derived. Employing Fermi-Dirac distribution at zero temperature, the dispersion relation of the extraordinary mode in a relativistic degenerate electron plasma is investigated. The propagation characteristics are examined in different relativistic density ranges. The shifting of cutoff points due to relativistic effects is observed analytically and graphically. Non-relativistic and ultra-relativistic limiting cases are also presented.
Expansion of Shockley stacking fault observed by scanning electron microscope and partial dislocation motion in 4H-SiC
Authors: Yamashita Yoshifumi , Nakata Ryu , Nishikawa Takeshi , Hada Masaki , Hayashi Yasuhiko
Published: January 2018

We studied the dynamics of the expansion of a Shockley-type stacking fault (SSF) with 30° Si(g) partial dislocations (PDs) using a scanning electron microscope. We observed SSFs as dark lines (DLs), which formed the contrast at the intersection between the surface and the SSF on the (0001) face inclined by 8° from the surface. We performed experiments at different electron-beam scanning speeds, observing magnifications, and irradiation areas. The results indicated that the elongation of a DL during one-frame scanning depended on the time for which the electron beam irradiated the PD segment in the frame of view. From these results, we derived a formula to express the velocity of the PD using the elongation rate of the corresponding DL during one-frame scanning. We also obtained the result that the elongation velocity of the DL was not influenced by changing the direction in which the electron beam irradiates the PD. From this result, we deduced that the geometrical kink motion of the PD was enhanced by diffusing carriers that were generated by the electron-beam irradiation.
Strain effects on the anisotropic thermal transport in crystalline polyethylene
Authors: He Jixiong , Kim Kyunghoon , Wang Yangchao , Liu Jun
Published: January 2018

Thermal transport in the axial direction of polymers has been extensively studied, while the strain effect on the thermal conductivity, especially in the radial direction, remains unknown. In this work, we calculated the thermal conductivity in the radial direction of a crystalline polyethylene model and simulated the uniaxial strain effect on the thermal conductivity tensor by molecular dynamics simulations. We found a strong size effect of the thermal transport in the radial direction and estimated that the phonon mean free path can be much larger than the prediction from the classic kinetic theory. We also found that the thermal conductivity in the axial direction increases dramatically with strain, while the thermal conductivity in the radial direction decreases with uniaxial strain. We attribute the reduction of thermal conductivity in the radial direction to the decreases in inter-chain van der Waals forces with strains. The facts that the chains in the crystalline polyethylene became stiffer and more ordered along the chain direction could be the reasons for the increasing thermal conductivity in the axial direction during stretching. Besides, we observed longer phonon lifetime in acoustic branches and higher group velocity in optical branches after uniaxial stretching. Our work provides fundamental understandings on the phonon transport in crystalline polymers, the structure-property relationship in crystalline polymers, and the strain effect in highly anisotropic materials.
Large reversible magnetostrictive effect of MnCoSi–based compounds prepared by high-magnetic-field solidification
Authors: Hu Q. B. , Hu Y. , Zhang S. , Tang W. , He X. J. , Li Z. , Cao Q. Q. , Wang D. H. , Du Y. W.
Published: January 2018

The MnCoSi compound is a potential magnetostriction material since the magnetic field can drive a metamagnetic transition from an antiferromagnetic phase to a high magnetization phase in it, which accompanies a large lattice distortion. However, a large driving magnetic field, magnetic hysteresis, and poor mechanical properties seriously hinder its application for magnetostriction. By substituting Fe for Mn and introducing vacancies of the Mn element, textured and dense Mn0.97Fe0.03CoSi and Mn0.88CoSi compounds are prepared through a high-magnetic-field solidification approach. As a result, large room-temperature and reversible magnetostriction effects are observed in these compounds at a low magnetic field. The origin of this large magnetostriction effect and potential applications are discussed.
Toward wideband steerable acoustic metasurfaces with arrays of active electroacoustic resonators
Authors: Lissek Hervé , Rivet Etienne , Laurence Thomas , Fleury Romain
Published: January 2018

We introduce an active concept for achieving acoustic metasurfaces with steerable reflection properties, effective over a wide frequency band. The proposed active acoustic metasurface consists of a surface array of subwavelength loudspeaker diaphragms, each with programmable individual active acoustic impedances allowing for local control over the different reflection phases over the metasurface. The active control framework used for controlling the reflection phase over the metasurface is derived from the Active Electroacoustic Resonator concept. Each unit-cell simply consists of a current-driven electrodynamic loudspeaker in a closed box, whose acoustic impedance at the diaphragm is judiciously adjusted by connecting an active electrical control circuit. The control is known to achieve a wide variety of acoustic impedances on a single loudspeaker diaphragm used as an acoustic resonator, with the possibility to shift its resonance frequency by more than one octave. This paper presents a methodology for designing such active metasurface elements. An experimental validation of the achieved individual reflection coefficients is presented, and full wave simulations present a few examples of achievable reflection properties, with a focus on the bandwidth of operation of the proposed control concept.
Ion-ion correlations across and between electrified graphene layers
Authors: Mendez-Morales Trinidad , Burbano Mario , Haefele Matthieu , Rotenberg Benjamin , Salanne Mathieu
Published: January 2018

When an ionic liquid adsorbs onto a porous electrode, its ionic arrangement is deeply modified due to a screening of the Coulombic interactions by the metallic surface and by the confinement imposed upon it by the electrode’s morphology. In particular, ions of the same charge can approach at close contact, leading to the formation of a superionic state. The impact of an electrified surface placed between two liquid phases is much less understood. Here we simulate a full supercapacitor made of the 1-butyl-3-methylimidazolium hexafluorophosphate and nanoporous graphene electrodes, with varying distances between the graphene sheets. The electrodes are held at constant potential by allowing the carbon charges to fluctuate. Under strong confinement conditions, we show that ions of the same charge tend to adsorb in front of each other across the graphene plane. These correlations are allowed by the formation of a highly localized image charge on the carbon atoms between the ions. They are suppressed in larger pores, when the liquid adopts a bilayer structure between the graphene sheets. These effects are qualitatively similar to the recent templating effects which have been reported during the growth of nanocrystals on a graphene substrate.
Effects of the evaporation rate on the segregation in drying bimodal colloidal suspensions
Authors: Tatsumi Rei , Iwao Takuya , Koike Osamu , Yamaguchi Yukio , Tsuji Yoshiko
Published: January 2018

When suspensions containing colloidal particles of two different sizes are coated on substrates to form films by evaporating the host fluids, the smaller particles can segregate to the top surface of the films. We investigate the effects of the evaporation rate on the segregation by use of Langevin dynamics simulations. The evaporation rate is scaled by the Brownian diffusion rate of the particles, yielding a dimensionless number which we define as the particle drying Péclet number. We show that there is a Péclet number at which the segregation is the most enhanced. Our result indicates the need for the regulation of the evaporation rate to control the segregation.
Phase transitions in single macromolecules: Loop-stretch transition versus loop adsorption transition in end-grafted polymer chains
Authors: Zhang Shuangshuang , Qi Shuanhu , Klushin Leonid I. , Skvortsov Alexander M. , Yan Dadong , Schmid Friederike
Published: January 2018

We use Brownian dynamics simulations and analytical theory to compare two prominent types of single molecule transitions. One is the adsorption transition of a loop (a chain with two ends bound to an attractive substrate) driven by an attraction parameter ε and the other is the loop-stretch transition in a chain with one end attached to a repulsive substrate, driven by an external end-force F applied to the free end. Specifically, we compare the behavior of the respective order parameters of the transitions, i.e., the mean number of surface contacts in the case of the adsorption transition and the mean position of the chain end in the case of the loop-stretch transition. Close to the transition points, both the static behavior and the dynamic behavior of chains with different length N are very well described by a scaling ansatz with the scaling parameters (ε − ε*)Nϕ (adsorption transition) and (F − F*)Nν (loop-stretch transition), respectively, where ϕ is the crossover exponent of the adsorption transition and ν is the Flory exponent. We show that both the loop-stretch and the loop adsorption transitions provide an exceptional opportunity to construct explicit analytical expressions for the crossover functions which perfectly describe all simulation results on static properties in the finite-size scaling regime. Explicit crossover functions are based on the ansatz for the analytical form of the order parameter distributions at the respective transition points. In contrast to the close similarity in equilibrium static behavior, the dynamic relaxation at the two transitions shows qualitative differences, especially in the strongly ordered regimes. This is attributed to the fact that the surface contact dynamics in a strongly adsorbed chain is governed by local processes, whereas the end height relaxation of a strongly stretched chain involves the full spectrum of Rouse modes.
Net W monolayer: A high-performance electrode material for Li-ion batteries
Authors: Yu Song , Rao Yong-Chao , Li Shun-Fang , Duan Xiang-Mei
Published: January 2018

“Two-dimensional materials as electrodes” is believed to be one of the key solutions for the development of future battery technologies. Based on the first-principles calculations, we predict that a metallic carbon allotrope (net W), with high electrochemical performance, can be served as an anode material for Li-ion batteries (LIBs). The net W exhibits metallic conductivity, and the conductivity is excellently maintained after Li adsorption. Specifically, upon Li intercalation, only slight lattice variations (<1.5%) occur, which ensures a good cycling stability. The low diffusion barriers of 0.4 eV and the moderate average open circuit voltage of 0.42 V are in between those of the currently used anodes, graphite, and TiO2. Most remarkably, the storage capacity can be up to 1675 mA h g−1, which is about 4.5 times larger than that of the commercial graphite anode. The present findings identify that net W could be an excellent anode material for the application in LIBs.
Non-adiabatic quantum reactive scattering in hyperspherical coordinates
Authors: Kendrick Brian K.
Published: January 2018

A new electronically non-adiabatic quantum reactive scattering methodology is presented based on a time-independent coupled channel formalism and the adiabatically adjusting principal axis hyperspherical coordinates of Pack and Parker [J. Chem. Phys. 87, 3888 (1987)]. The methodology computes the full state-to-state scattering matrix for A + B2(v, j) ↔ AB(v′, j′) + B and A + AB(v, j) → A + AB(v′, j′) reactions that involve two coupled electronic states which exhibit a conical intersection. The methodology accurately treats all six degrees of freedom relative to the center-of-mass which includes non-zero total angular momentum J and identical particle exchange symmetry. The new methodology is applied to the ultracold hydrogen exchange reaction for which large geometric phase effects have been recently reported [B. K. Kendrick et al., Phys. Rev. Lett. 115, 153201 (2015)]. Rate coefficients for the H/D + HD(v = 4, j = 0) → H/D + HD(v′, j′) reactions are reported for collision energies between 1 μK and 100 K (total energy ≈1.9 eV). A new diabatic potential energy matrix is developed based on the Boothroyd, Keogh, Martin, and Peterson (BKMP2) and double many body expansion plus single-polynomial (DSP) adiabatic potential energy surfaces for the ground and first excited electronic states of H3, respectively. The rate coefficients computed using the new non-adiabatic methodology and diabatic potential matrix reproduce the recently reported rates that include the geometric phase and are computed using a single adiabatic ground electronic state potential energy surface (BKMP2). The dramatic enhancement and suppression of the ultracold rates due to the geometric phase are confirmed as well as its effects on several shape resonances near 1 K. The results reported here represent the first fully non-adiabatic quantum reactive scattering calculation for an ultracold reaction and validate the importance of the geometric phase on the Wigner threshold behavior.
Cation effect on small phosphonium based ionic liquid electrolytes with high concentrations of lithium salt
Authors: Chen Fangfang , Kerr Robert , Forsyth Maria
Published: January 2018

Ionic liquid electrolytes with high alkali salt concentrations have displayed some excellent electrochemical properties, thus opening up the field for further improvements to liquid electrolytes for lithium or sodium batteries. Fundamental computational investigations into these high concentration systems are required in order to gain a better understanding of these systems, yet they remain lacking. Small phosphonium-based ionic liquids with high concentrations of alkali metal ions have recently shown many promising results in experimental studies, thereby prompting us to conduct further theoretical exploration of these materials. Here, we conducted a molecular dynamics simulation on four small phosphonium-based ionic liquids with 50 mol. % LiFSI salt, focusing on the effect of cation structure on local structuring and ion diffusional and rotational dynamics—which are closely related to the electrochemical properties of these materials.
Achieving polydimethylsiloxane/carbon nanotube (PDMS/CNT) composites with extremely low dielectric loss and adjustable dielectric constant by sandwich structure
Authors: Fan Benhui , Liu Yu , He Delong , Bai Jinbo
Published: January 2018

Sandwich-structured composites of polydimethylsiloxane/carbon nanotube (PDMS/CNT) bulk between two neat PDMS thin films with different thicknesses are prepared by the spin-coating method. Taking advantage of CNT's percolation behavior, the composite keeps relatively high dielectric constant (ε′ = 40) at a low frequency (at 100 Hz). Meanwhile, due to the existence of PDMS isolated out-layers which limits the conductivity of the composite, the composite maintains an extremely low dielectric loss (tan δ = 0.01) (at 100 Hz). Moreover, the same matrix of the out-layer and bulk can achieve excellent interfacial adhesion, and the thickness of the coating layer can be controlled by a multi-cycle way. Then, based on the experimental results, the calculation combining the percolation theory and core-shell model is used to analyze the thickness effect of the coating layer on ε′. The obtained relationship between the ε′ of the composite and the thickness of the coating layer can help to optimize the sandwich structure in order to obtain the adjustable ε′ and the extremely low tan δ.
High order analysis of the limit cycle of the van der Pol oscillator
Authors: Amore Paolo , Boyd John P. , Fernández Francisco M.
Published: January 2018

We have applied the Lindstedt-Poincaré method to study the limit cycle of the van der Pol oscillator, obtaining the numerical coefficients of the series for the period and for the amplitude to order 859. Hermite-Padé approximants have been used to extract the location of the branch cut of the series with unprecedented accuracy (100 digits). Both series have then been resummed using an approach based on Padé approximants, where the exact asymptotic behaviors of the period and the amplitude are taken into account. Our results improve drastically all previous results obtained on this subject.
Lanthanum-mediated dehydrogenation of butenes: Spectroscopy and formation of La(C4H6) isomers
Authors: Cao Wenjin , Hewage Dilrukshi , Yang Dong-Sheng
Published: January 2018

La atom reactions with 1-butene, 2-butene, and isobutene are carried out in a laser-vaporization molecular beam source. The three reactions yield the same La-hydrocarbon products from the dehydrogenation and carbon-carbon bond cleavage and coupling of the butenes. The dehydrogenated species La(C4H6) is the major product, which is characterized with mass-analyzed threshold ionization (MATI) spectroscopy and quantum chemical computations. The MATI spectrum of La(C4H6) produced from the La+1-butene reaction exhibits two band systems, whereas the MATI spectra produced from the La+2-butene and isobutene reactions display only a single band system. Each of these spectra shows a strong origin band and several vibrational progressions. The two band systems from the spectrum of the 1-butene reaction are assigned to the ionization of two isomers: La[C(CH2)3] (Iso A) and La(CH2CHCHCH2) (Iso B), and the single band system from the spectra of the 2-butene and isobutene reactions is attributed to Iso B and Iso A, respectively. The ground electronic states are 2A1 (C3v) for Iso A and 2A′ (Cs) for Iso B. The ionization of the doublet state of each isomer removes a La 6s-based electron and leads to the 1A1 ion of Iso A and the 1A′ ion of Iso B. The formation of both isomers consists of La addition to the C=C double bond, La insertion into two C(sp3)—H bonds, and H2 elimination. In addition to these steps, the formation of Iso A from the La+1-butene reaction may involve the isomerization of 1-butene to isobutene prior to the C—H bond activation, whereas the formation of Iso B from the La+trans-2-butene reaction may include the trans- to cis-butene isomerization after the C—H bond activation.
SIMS study of oxygen diffusion in monoclinic HfO2
Authors: Mueller Michael P. , De Souza Roger A.
Published: January 2018

The diffusion of oxygen in dense ceramics of monoclinic HfO2 was studied by means of (18O/16O) isotope exchange annealing and subsequent determination of isotope depth profiles by Secondary Ion Mass Spectrometry. Anneals were performed in the temperature range of 573 ≤T/K≤ 973 at an oxygen partial pressure of pO2=200 mbar. All measured isotope profiles exhibited two features: the first feature, closer to the surface, was attributed mainly to slow oxygen diffusion in an impurity silicate phase; the second feature, deeper in the sample, was attributed to oxygen diffusion in bulk monoclinic HfO2. The activation enthalpy of oxygen tracer diffusion in bulk HfO2 was found to be ΔHD∗≈0.5 eV.
Targeted delivery of anti-tuberculosis drugs to macrophages: targeting mannose receptors
Authors: Filatova Lyubov Yu. , Klyachko Natalia L. , Kudryashova Elena V.
Published: January 2018

The development of systems for targeted delivery of anti-tuberculosis drugs is a challenge of modern biotechnology. Currently, these drugs are encapsulated in a variety of carriers such as liposomes, polymers, emulsions and so on. Despite successful in vitro testing of these systems, virtually no success was achieved in vivo, because of low accessibility of the foci of infection located in alveolar macrophage cells. A promising strategy for increasing the efficiency of therapeutic action of anti-tuberculosis drugs is to encapsulate the agents into mannosylated carriers targeting the mannose receptors of alveolar macrophages. The review addresses the methods for modification of drug substance carriers, such as liposomes and biodegradable polymers, with mannose residues. The use of mannosylated carriers to deliver anti-tuberculosis agents increases the drug circulation time in the blood stream and increases the drug concentration in alveolar macrophage cells.

The bibliography includes 113 references.
Iterative near-term ecological forecasting: Needs, opportunities, and challenges
Authors: Dietze Michael C. , Fox Andrew , Beck-Johnson Lindsay M. , Betancourt Julio L. , Hooten Mevin B. , Jarnevich Catherine S. , Keitt Timothy H. , Kenney Melissa A. , Laney Christine M. , Larsen Laurel G. , Loescher Henry W. , Lunch Claire K. , Pijanowski Bryan C. , Randerson James T. , Read Emily K. , Tredennick Andrew T. , Vargas Rodrigo , Weathers Kathleen C. , White Ethan P.
Published: January 2018

Two foundational questions about sustainability are “How are ecosystems and the services they provide going to change in the future?” and “How do human decisions affect these trajectories?” Answering these questions requires an ability to forecast ecological processes. Unfortunately, most ecological forecasts focus on centennial-scale climate responses, therefore neither meeting the needs of near-term (daily to decadal) environmental decision-making nor allowing comparison of specific, quantitative predictions to new observational data, one of the strongest tests of scientific theory. Near-term forecasts provide the opportunity to iteratively cycle between performing analyses and updating predictions in light of new evidence. This iterative process of gaining feedback, building experience, and correcting models and methods is critical for improving forecasts. Iterative, near-term forecasting will accelerate ecological research, make it more relevant to society, and inform sustainable decision-making under high uncertainty and adaptive management. Here, we identify the immediate scientific and societal needs, opportunities, and challenges for iterative near-term ecological forecasting. Over the past decade, data volume, variety, and accessibility have greatly increased, but challenges remain in interoperability, latency, and uncertainty quantification. Similarly, ecologists have made considerable advances in applying computational, informatic, and statistical methods, but opportunities exist for improving forecast-specific theory, methods, and cyberinfrastructure. Effective forecasting will also require changes in scientific training, culture, and institutions. The need to start forecasting is now; the time for making ecology more predictive is here, and learning by doing is the fastest route to drive the science forward.