bluuebunny/crossref_metadata_2025 huggingface dataset:
Single-molecule imaging of telomerase activity via linear plasmon rulers
Authors: Qian Guang-Sheng , Zhang Ting-Ting , Zhao Wei , Xu Jing-Juan , Chen Hong-Yuan
Published: March 2017

A strategy for real-time monitoring of the extension of the telomerase primer based on plasmon rulers was demonstrated for the first time.
A long persistence phosphor tailored quasi-solid-state dye-sensitized solar cell that generates electricity in sunny and dark weathers
Authors: Tang Qunwei , Wang Min , Wang Zhongling , Sun Weiyin , Shang Ruoxu
Published: March 2017

An all-weather quasi-solid-state dye-sensitized solar cell is built using a long persistence phosphor tailored mesoscopic TiO2 photoanode and a three-dimensional conducting polymer gel electrolyte.
Synthesis of Ca(PF6)2, formed via nitrosonium oxidation of calcium
Authors: Keyzer Evan N. , Matthews Peter D. , Liu Zigeng , Bond Andrew D. , Grey Clare P. , Wright Dominic S.
Published: March 2017

Ca(PF6)2, a potential Ca-ion battery electrolyte salt, is stabilized towards oxidation by crown ether ligands; however, forced oxidation of the Ca⊂crown complex affords an unprecedented Ca4F4 cubanoid cluster.
Effects of water on low-overpotential CO2 reduction in ionic liquid studied by sum-frequency generation spectroscopy
Authors: García Rey Natalia , Dlott Dana D.
Published: March 2017

Adding water lowers the RTIL structural transition potential and the CO2 reduction threshold potential. Multiply-bonded CO is likely the more efficient catalytic site.
Insights into water-mediated ion clustering in aqueous CaSO4solutions: pre-nucleation cluster characteristics studied by ab initio calculations and molecular dynamics simulations
Authors: Li Hui-Ji , Yan Dan , Cai Hou-Qin , Yi Hai-Bo , Min Xiao-Bo , Xia Fei-Fei
Published: March 2017

Neutral clusters are typical species in pre-nucleation processes; the dynamics of water molecules around CaSO4clusters slow down due to dual reorientation.
Surface reactivity and vacancy defects in single-layer borophene polymorphs
Authors: Kulish Vadym V.
Published: March 2017

We present a systematic study on the surface reactivity of single-layer borophene polymorphs.
Revisiting the definition of local hardness and hardness kernel
Authors: Polanco-Ramírez Carlos A. , Franco-Pérez Marco , Carmona-Espíndola Javier , Gázquez José L. , Ayers Paul W.
Published: March 2017

Local hardness is redefined following similar rules to those of local softness. The new concept describes chemical trends correctly.
Diels–Alder reactions of graphene oxides: greatly enhanced chemical reactivity by oxygen-containing groups
Authors: Tang Shaobin , Wu Weihua , Liu Liangxian , Cao Zexing , Wei Xiaoxuan , Chen Zhongfang
Published: March 2017

Oxygen-containing groups of graphene oxides greatly enhanced the Diels–Alder (DA) reactivity of pristine graphene.
The importance of transport property studies for battery electrolytes: revisiting the transport properties of lithium–N-methyl-N-propylpyrrolidinium bis(fluorosulfonyl)imide mixtures
Authors: Rüther Thomas , Kanakubo Mitsuhiro , Best Adam S. , Harris Kenneth R.
Published: March 2017

All three ion–ion interactions contribute to transport properties in {Li[FSI]–[Pyr13][FSI]} mixtures. Tracer diffusion coefficients of LI+in [Pyr13][FSI] are predicted.
Decoupling diffusion from the bimolecular photoinduced electron transfer reaction: a combined ultrafast spectroscopic and kinetic analysis
Authors: Mukherjee Puspal , Sen Pratik
Published: March 2017

We have studied the bimolecular photoinduced electron transfer (PET) reaction between benzophenone (Bp) and DABCO using femtosecond broadband transient absorption spectroscopy in different compositions of acetonitrile/1-butanol binary solvent mixtures.
Accelerating direct quantum dynamics using graphical processing units
Authors: Penfold T. J.
Published: March 2017

The direct dynamics variational multi-configurational Gaussian (DD-vMCG) method is combined with electronic structure calculations accelerated by Graphical Processing Units (GPUs). This is used to identify GPU acceleration will have a significant effect for both ground and excited state simulations.
Correction: Understanding MAOS through computational chemistry
Authors: Prieto P. , de la Hoz A. , Díaz-Ortiz A. , Rodríguez A. M.
Published: March 2017

Correction for ‘Understanding MAOS through computational chemistry’ by P. Prieto et al., Chem. Soc. Rev., 2017, 46, 431–451.
Surface composition and structural changes on titanium oxide-supported AuPd nanoparticles during CO oxidation
Authors: Teixeira-Neto A. A. , Gonçalves R. V. , Rodella C. B. , Rossi L. M. , Teixeira-Neto E.
Published: March 2017

Catalysts with the same composition but different initial morphologies showed an unexpected morphological convergence after performing the CO oxidation reaction.
Theoretical and experimental studies on the structure–property relationship of chiral N,N′-dioxide–metal catalysts probed by the carbonyl–ene reaction of isatin
Authors: Wang Junming , Zuo Yini , Hu Changwei , Su Zhishan
Published: March 2017

Variation of the linkage or chiral backbone of an N,N′-dioxide ligand adjusts the blocking effect of ortho-iPr on the reaction site, affecting the enantiodifferentiation of two competing pathways.
Synthesis and conformations of [2.n]metacyclophan-1-ene epoxides and their conversion to [n.1]metacyclophanes
Authors: Akther Thamina , Islam Md. Monarul , Rahman Shofiur , Georghiou Paris E. , Matsumoto Taisuke , Tanaka Junji , Redshaw Carl , Yamato Takehiko
Published: March 2017

Acid catalyzed rearrangement reactions of [2.n]metacyclophan-1-enes afford new chiral [n.1]metacyclophanes; DFT calculations have been used to estimate the energy-minimized structures of the metacyclophanes.
A CTA-shuttled R-group approach: a versatile synthetic tool towards well-defined functional cylindrical polymer brushes via RAFT polymerization
Authors: Wang Yifei , Zheng Zhicheng , Huang Zhengdong , Ling Jun
Published: March 2017

We report a novel three-step strategy toward polyCTA for the synthesis of cylindrical polymer brushes via “CTA-shuttled” RAFT R-approach polymerization. Post functionalizations on the CTA residue are also discussed.
Colorimetric detection of cholic acid based on an aptamer adsorbed gold nanoprobe
Authors: Zhu Qiuyun , Li Tingting , Ma Yi , Wang Zhaohui , Huang Jinxin , Liu Ruonan , Gu Yueqing
Published: March 2017

Au NPs modified with aptamers of different densities will grow into varied nanostructures with colours changing from blue to red.
Fast microwave-assisted conjugation of magnetic nanoparticles with carboxylates of biological interest
Authors: Gutiérrez M. S. , Piña M. N. , Morey J.
Published: March 2017

A new technique of surface modification of nanoparticles (Fe3O4-NP) with carboxylates of biological interest has been developed with a microwave-assisted heating method.
Preferential stabilization of HeI2 van der Waals isomers: the effect of energetics and temperature
Authors: Valdés Álvaro , Prosmiti Rita
Published: March 2017

Energetics and temperature dependence on the preferential stabilization of the linear/T-shaped HeI2 isomers.
Highly sensitive electrochemical determination of captopril using CuO modified ITO electrode: the effect of in situ grown nanostructures over signal sensitivity
Authors: Soomro Razium Ali , Tunesi Mawada Mohamed , Karakus Selcan , Kalwar Nazar
Published: March 2017

Influence of nanostructures distribution over electrochemical signal sensitivity.
Effect of fluoro-polycarbonates containing aliphatic/aromatic segments on the characteristics of thermo-optic waveguide devices
Authors: Cai Zhenzhen , Yu Qixuan , Zheng Yang , Shi Xiaoyu , Wang Xuesong , Cui Zhanchen , Shi Zuosen , Chen Changming , Zhang Daming
Published: March 2017

A series of photoresists was prepared to investigate the effects of flexibility on the properties of thermo-optic waveguide devices.
Facile hydrothermal fabrication of ZnO–graphene hybrid anode materials with excellent lithium storage properties
Authors: Feng Yan , Zhang Yuliang , Song Xiangyun , Wei Yuzhen , Battaglia Vincent S.
Published: March 2017

ZnO–graphene hybrid materials were synthesizedviaa hydrothermal fabrication method. As cathodes for Li-ion batteries, their electrochemical performances are investigated.
A transparent solar cell based on a mechanically exfoliated GaTe and InGaZnO p–n heterojunction
Authors: Cho Ah-Jin , Park Kyung , Park Solah , Song Min-Kyu , Chung Kwun-Bum , Kwon Jang-Yeon
Published: March 2017

A highly transparent solar cell was achieved by utilizing a GaTe/IGZO p–n heterojunction as an active layer.
A role for galectin-3 in the development of early molecular alterations in short-term aortic stenosis
Authors: Arrieta Vanessa , Martinez-Martinez Ernesto , Ibarrola Jaime , Alvarez Virginia , Sádaba Rafael , Garcia-Peña Amaia , Fernández-Celis Amaya , Cachofeiro Victoria , Rossignol Patrick , López-Andrés Natalia
Published: March 2017

Aortic stenosis (AS) is characterized by pressure overload and causes left ventricular (LV) fibrosis and inflammation, two mechanisms that eventually lead to cardiac dysfunction. Galectin-3 (Gal-3), a β-galactoside-binding lectin, promotes cardiac remodelling. In the present study, we investigated the role of Gal-3 in LV remodelling in patients with AS and the effects of Gal-3 blockade in rats subjected to short-term (6-week) supravalvular aortic banding (AS group). Myocardial biopsies were obtained from 25 patients with severe AS referred for aortic valve replacement and from necropsies of 11 cardiovascular disease-free control individuals. Gal-3 was up-regulated in myocardial biopsies from AS patients compared with controls. Gal-3 directly correlated with parameters assessing myocardial fibrosis and inflammation in AS patients. Normotensive AS animals presented decreased LV diastolic diameter compared with controls. At the histological level, AS rats exhibited a slight increase in LV cross-sectional area and LV wall thickness, and augmented cardiomyocyte width and cross-sectional area. AS animals presented enhanced cardiac Gal-3 expression, which paralleled higher myocardial fibrosis and inflammation. Cardiac Gal-3 was associated with fibrosis and inflammatory markers. Gal-3 pharmacological inhibition prevented the increase in cardiac Gal-3 and normalized histological and molecular alterations in AS rats. In short-term AS, the increase in myocardial Gal-3 expression was associated with cardiac fibrosis and inflammation, alterations that were prevented by Gal-3 blockade. These data suggest that Gal-3 inhibition could be a novel therapeutic approach in the prevention of AS-associated early pathological cardiac remodelling.
Uplink MU‐based channel access scheme for high‐throughput of multiple users
Authors: Ku Eunbi , Chung Chulho , Kang Byungcheol , Kim Jaeseok
Published: March 2017

A new channel access scheme to improve the throughput in the medium access control layer is proposed to support the high data rate of multiple users. The proposed scheme is based on access point‐coordinated multiuser transmission via the adoption of a trigger frame. The total throughput of the proposed scheme is improved by up to 30% compared with the uplink‐multiuser channel access scheme based on the request to send/clear to send exchange. Moreover, as the number of stations increases, the degree of improvement in performance increases.
Online condition monitoring system for substation and service transformers
Authors: Ballal Makarand S. , Jaiswal Gajanan C. , Tutkane Dhananjay R. , Venikar Prasad A. , Mishra Mahesh Kumar , Suryawanshi Hiralal M.
Published: March 2017

Deregulation in power industry accelerates competition among various power companies. These companies are trying to gain maximum profit with minimum maintenance cost. This could be achieved by developing a condition‐based monitoring product for the assessment of health of substation and service transformers. This study presents online condition monitoring system (OCMS) for transformers which is useful to replace reactive and preventive maintenance of transformers by predictive maintenance. Proposed OCMS is cost effective, online and accurate tool and it has several features like proposing corrective actions for the benefit of power utilities. Proposed system results are evaluated by comparing with the results obtained from utility model. Proposed OCMS applies only to transformers without abnormal faults such as detected by dissolved gas analysis. It is therefore very different from the other health index algorithms present in the market for condition monitoring of transformers, including in case of abnormal faults.
Design and application of a mobile miniature current probe for analysing the cause of EMI noise in IC circuits
Authors: Lin Han‐Nien , Chen Hung‐Chi , Kuo Chung‐Wei , Chang Yen‐Tang
Published: March 2017

This study is based on International Electrotechnical Commission (IEC) 61967‐4 standards for measuring electromagnetic emissions and interferences at the chip level. Conventional measurement methods using fixed SMA connectors were replaced with an improved radio frequency current probe featuring semi‐rigid coaxial cables, making it capable of taking mobile measurements, enhancing the flexibility and convenient probing usage. To effectively assess the practical value of the improved probe, the authors have referred to the standard designs provided in IEC 61967‐1 to manufacture a four‐layer digital circuit board that controls the screen of an on‐board navigational screen for automobiles. Circuit board electromagnetic interference (EMI) noise frequency and level readings from the improved probe were also compared with three other measurement methods, namely magnetic field probes available in the market, TEM cells, and the 10‐m far‐field measurement method. The results demonstrated the capability of the improved probe to effectively identify sources of noise at the chip‐level during the IC design phases, helping with root cause analysis and allowing EMI noises experienced by the product to be solved promptly during the process of electromagnetic compatibility design optimisation and analysis.
Herschel survey and modelling of externally-illuminated photoevaporating protoplanetary disks
Authors: Champion J. , Berné O. , Vicente S. , Kamp I. , Le Petit F. , Gusdorf A. , Joblin C. , Goicoechea J. R.
Published: March 2017

Context. Protoplanetary disks undergo substantial mass-loss by photoevaporation, a mechanism that is crucial to their dynamical evolution. However, the processes regulating the gas energetics have not so far been well constrained by observations.

Aims. We aim to study the processes involved in disk photoevaporation when it is driven by far-UV photons (i.e. 6 < E < 13.6 eV).

Methods. We present a unique Herschel survey and new ALMA observations of four externally-illuminated photoevaporating disks (a.k.a. proplyds). To analyse these data, we developed a 1D model of the photodissociation region (PDR) of a proplyd, based on the Meudon PDR code. Using this model, we computed the far infrared line emission.

Results. With this model, we successfully reproduce most of the observations and derive key physical parameters, that is, the densities at the disk surface of about 106 cm-3 and local gas temperatures of about 1000 K. Our modelling suggests that all studied disks are found in a transitional regime resulting from the interplay between several heating and cooling processes that we identify. These differ from those dominating in classical PDRs, meaning the grain photo-electric effect and cooling by [OI] and [CII] FIR lines. This specific energetic regime is associated to an equilibrium dynamical point of the photoevaporation flow: the mass-loss rate is self-regulated to keep the envelope column density at a value that maintains the temperature at the disk surface around 1000 K. From the physical parameters derived from our best-fit models, we estimate mass-loss rates – of the order of 10-7M⊙/yr – that are in agreement with earlier spectroscopic observation of ionised gas tracers. This holds only if we assume photoevaporation in the supercritical regime where the evaporation flow is launched from the disk surface at sound speed.

Conclusions. We have identified the energetic regime regulating FUV-photoevaporation in proplyds. This regime could be implemented into models of the dynamical evolution of protoplanetary disks.
Endolymphatic Sac Surgery for Ménière's Disease – Current Opinion and Literature Review
Authors: Flores García Maria , Llata Segura Carolina , Cisneros Lesser Juan , Pane Pianese Carlo
Published: March 2017

Introduction The endolymphatic sac is thought to maintain the hydrostatic pressure and endolymph homeostasis for the inner ear, and its dysfunction may contribute to the pathophysiology of Ménière's disease. Throughout the years, different surgical procedures for intractable vertigo secondary to Ménière's disease have been described, and though many authors consider these procedures as effective, there are some who question its long-term efficacy and even those who think that vertigo control is achieved more due to a placebo effect than because of the procedure itself.

Objective To review the different surgical procedures performed in the endolymphatic sac for the treatment of Ménière's disease.

Data Sources PubMed, MD consult and Ovid-SP databases.

Data Synthesis We focus on describing the different surgical procedures performed in the endolymphatic sac, such as endolymphatic sac decompression, endolymphatic sac enhancement, endolymphatic sac shunting and endolymphatic duct blockage, their pitfalls and advantages, their results in vertigo control and the complication rates. The senior author also describes his experience after 30 years of performing endolymphatic sac surgery.

Conclusions The endolymphatic sac surgery, with all its variants, is a good option for patients with incapacitating endolymphatic hydrops, providing a high percentage of vertigo control and hearing preservation.
Super-Thin and Suprafascial Anterolateral Thigh Perforator Flaps for Extremity Reconstruction
Authors: Seth Akhil , Iorio Matthew
Published: March 2017

Background The anterolateral thigh (ALT) flap remains a workhorse for soft tissue reconstruction. However, the traditional ALT flap is often too bulky for resurfacing shallow, distal extremity defects, prohibiting adequate function, or well-fitted orthotics. This study evaluates extremity reconstruction using ALT flaps elevated in the suprafascial or super-thin plane.

Methods Retrospective review of ALT free flap reconstruction from October 2014 to July 2016 was performed. Suprafascial and super-thin flaps were those elevated just above the crural fascia and within the superficial scarpal plane, respectively. Adjunct operative procedures, demographics, and complications were recorded.

Results A total of 25 patients underwent suprafascial (n = 14) or super-thin (n = 11) ALT flap reconstruction for primarily lower extremity wounds (n = 19), with an average age and body mass index of 53.8 years and 26.3 kg/m2, respectively. Follow-up was 6.3 months. Comorbidities included smoking (n = 7), diabetes (n = 8), peripheral vascular disease (n = 6), and hypertension (n = 8). The presence of hardware (n = 9), trauma (n = 10), and chronic infection (n = 12) were common risk factors. Average flap size was 8.2 × 21.5 cm, with 64% (n = 16) taken on one perforator. Forty-eight percent (n = 12) were end-to-side anastomoses and 62% (n = 13) utilized one venous anastomosis. Mean hospital stay was 7.8 days with a 24% (n = 6) complication rate. There were no partial or complete flap losses.

Conclusion The ALT flap, elevated in a suprafascial or super-thin plane, is a safe, effective option for extremity soft tissue reconstruction. The decreased flap volume and bulk provides the improved contour and pliability necessary for appropriate distal extremity function. The potential versatility of super-thin flaps reinforces the importance of continued innovation by reconstructive microsurgeons.
Ovarian Manson's Schistosomiasis: Rare Diagnosis or Underestimated Prevalence?
Authors: Gomes Elainne Christine de Souza , Domingues Ana Lúcia Coutinho , Aguiar Júnior Francisco Carlos Amanajás de , Barbosa Constança Simões
Published: March 2017

The occurrence of Manson's schistosomiasis in organs of the female reproductive tract is an uncommon event, given that the etiological agent for this disease is a blood parasite that inhabits the mesenteric veins. In this case report, a 45-year-old female patient reported that her first symptoms had been strong pain in the left iliac region around two years earlier. An endovaginal pelvic ultrasonography showed that the left ovary was enlarged, and the report suggested that this finding might be correlated with clinical data and tumor markers. After being examined at several healthcare services, the patient was referred to an oncology service due to suspected neoplasia, where she underwent a left ovariectomy. The result from the histopathological examination showed the presence of granulomatous inflammatory processes surrounding both viable and calcified eggs of Schistosoma mansoni. There was no evidence of any neoplastic tissue. The patient was medicated and followed-up as an outpatient.
Correcting density-driven errors in projection-based embedding
Authors: Pennifold Robert C. R. , Bennie Simon J. , Miller Thomas F. , Manby Frederick R.
Published: March 2017

Projection-based embedding provides a simple and numerically robust framework for multiscale wavefunction-in-density-functional-theory (WF-in-DFT) calculations. The approach works well when the approximate DFT is sufficiently accurate to describe the energetics of the low-level subsystem and the coupling between subsystems. It is also necessary that the low-level DFT produces a qualitatively reasonable description of the total density, and in this work, we study model systems where delocalization error prevents this from being the case. We find substantial errors in embedding calculations on open-shell doublet systems in which self-interaction errors cause spurious delocalization of the singly occupied orbital. We propose a solution to this error by evaluating the DFT energy using a more accurate self-consistent density, such as that of Hartree-Fock (HF) theory. These so-called WF-in-(HF-DFT) calculations show excellent convergence towards full-system wavefunction calculations.
Adsorption-induced deformation of nanoporous materials—A review
Authors: Gor Gennady Y. , Huber Patrick , Bernstein Noam
Published: March 2017

When a solid surface accommodates guest molecules, they induce noticeable stresses to the surface and cause its strain. Nanoporous materials have high surface area and, therefore, are very sensitive to this effect called adsorption-induced deformation. In recent years, there has been significant progress in both experimental and theoretical studies of this phenomenon, driven by the development of new materials as well as advanced experimental and modeling techniques. Also, adsorption-induced deformation has been found to manifest in numerous natural and engineering processes, e.g., drying of concrete, water-actuated movement of non-living plant tissues, change of permeation of zeolite membranes, swelling of coal and shale, etc. In this review, we summarize the most recent experimental and theoretical findings on adsorption-induced deformation and present the state-of-the-art picture of thermodynamic and mechanical aspects of this phenomenon. We also reflect on the existing challenges related both to the fundamental understanding of this phenomenon and to selected applications, e.g., in sensing and actuation, and in natural gas recovery and geological CO2 sequestration.
Laboratory-based high pressure X-ray photoelectron spectroscopy: A novel and flexible reaction cell approach
Authors: Kerherve Gwilherm , Regoutz Anna , Bentley David , Hood Colin , Feeley Keith , Knight Stewart , Robson Anthony , Turner Craig , Singh Nick , Pontefract John , Åhlund John , Kahk Juhan M. , Villar-Garcia Ignacio J. , Payne David J.
Published: March 2017

The last 10-15 years have witnessed a resurgence in the application of high pressure X-ray photoelectron spectroscopy, mainly through the development of new electron energy analyser designs and the utilization of high-brilliance synchrotron radiation sources. To continue this expansion of the technique, it is crucial that instruments are developed for the home-laboratory, considering that this is where the vast majority of traditional ultra-high vacuum (UHV) X-ray photoelectron spectroscopy is performed. The research presented here introduces a new addition to the field, an instrument capable of performing spectroscopy measurements from UHV to high pressure (25 mbar), achieved using a retractable and modular reaction cell design. The ease of use, stability (of analyser, X-ray source, and gas delivery, etc.), and overall capability of the instrument will be demonstrated.
Electric-dipole-coupled H2O@C60 dimer: Translation-rotation eigenstates from twelve-dimensional quantum calculations
Authors: Felker Peter M. , Bačić Zlatko
Published: March 2017

We report on variational solutions to the twelve-dimensional (12D) Schrödinger equation appertaining to the translation-rotation (TR) eigenstates of H2O@C60 dimer, associated with the quantized “rattling” motions of the two encapsulated H2O molecules. Both H2O and C60 moieties are treated as rigid and the cage-cage geometry is taken to be fixed. We consider the TR eigenstates of H2O@C60 monomers in the dimer to be coupled by the electric dipole-dipole interaction between water moieties and develop expressions for computing the matrix elements of that interaction in a dimer basis composed of products of monomer 6D TR eigenstates reported by us recently [P. M. Felker and Z. Bačić, J. Chem. Phys. 144, 201101 (2016)]. We use these expressions to compute TR Hamiltonian matrices of H2O@C60 dimer for two values of the water dipole moment and for various dimer geometries. 12D TR eigenstates of the dimer are then obtained by filter diagonalization. The results reveal two classes of eigenstates, distinguished by the leading order (first or second) at which dipole-dipole coupling contributes to them. The two types of eigenstates differ in the general magnitude of their dipole-induced energy shifts and in the dependence of those shifts on the value of the water dipole moment and on the distance between the H2O@C60 monomers. The dimer results are also found to be markedly insensitive to any change in the orientations of the C60 cages. Finally, the results lend some support for the interpretation that electric dipole-dipole coupling is at least partially responsible for the apparent reduced-symmetry environment experienced by H2O in the powder samples of H2O@C60 [K. S. K. Goh et al., Phys. Chem. Chem. Phys. 16, 21330 (2014)], but only if the water dipole is taken to have a magnitude close to that of free water. The methodology developed in the paper is transferable directly to the calculation of TR eigenstates of larger H2O@C60 assemblies, that will be required for more extensive modeling of crystalline H2O@C60.
Signatures of Herzberg–Teller coupling in three-dimensional electronic spectroscopy
Authors: Bizimana Laurie A. , Carbery William P. , Gellen Tobias A. , Turner Daniel B.
Published: March 2017

The coupling between electronic and nuclear variables is a key consideration in molecular dynamics and spectroscopy. However, simulations that include detailed vibronic coupling terms are challenging to perform, and thus a variety of approximations can be used to model and interpret experimental results. Recent work shows that these simplified models can be inadequate. It is therefore important to understand spectroscopic signals that can identify failures of those approximations. Here we use an extended response-function method to simulate coherent three-dimensional electronic spectroscopy (3D ES) and study the sensitivity of this method to the breakdown of the Franck–Condon approximation. The simulations include a coordinate-dependent transition dipole operator that produces nodes, phase shifts, and peak patterns in 3D ES that can be used to identify Herzberg–Teller coupling. Guided by the simulation results, we interpret measurements on a molecular aggregate.
In situ surface potential evolution along Au/Gd:CeO2 electrode interfaces
Authors: Zhu Jiaxin , Wang Jiaying , Mebane David S. , Nonnenmann Stephen S.
Published: March 2017

We present an investigation of electroactive Au/gadolinium doped ceria electrode interfaces under CO2/CO co-electrolysis environments using a combination of in situ high temperature scanning surface potential microscopy (HT-SSPM) and modified Poisson-Cahn (PC) models. Here charged surface adsorbate-oxygen vacancy interactions manifested in HT-SSPM potential profiles as small perturbations of opposite sign in reference to the applied biases. The positive deviation of surface potential on Au from applied cathodic biases is attributed to the work function difference between gold (ϕAu ∼ 5.31 eV) and graphitic carbon deposits (ϕC ∼ 5.0 eV) formed through CO disproportionation. The negative potential deviation from the applied anodic bias is attributed to negatively charged carboxylates. Results of the PC model confirmed the affinity of oxygen vacancies for the surface, thus supporting in situ experimental evidence of surface vacancy accumulation/depletion processes induced by cathodic/anodic biases.
An all-solid-state microsecond-range quasi-square pulse generator based on fractional-turn ratio saturable pulse transformer and anti-resonance network
Authors: Chen Rong , Yang Jianhua , Cheng Xinbing , Pan Zilong
Published: March 2017

High voltage pulse generators are widely applied in a number of fields. Defense and industrial applications stimulated intense interests in the area of pulsed power technology towards the system with high power, high repetition rate, solid state characteristics, and compact structure. An all-solid-state microsecond-range quasi-square pulse generator based on a fractional-turn ratio saturable pulse transformer and anti-resonance network is proposed in this paper. This generator consists of a charging system, a step-up system, and a modulating system. In this generator, the fractional-turn ratio saturable pulse transformer is the key component since it acts as a step-up transformer and a main switch during the working process. Demonstrative experiments show that if the primary storage capacitors are charged to 400 V, a quasi-square pulse with amplitude of about 29 kV can be achieved on a 3500 Ω resistive load, as well as the pulse duration (full width at half maximum) of about 1.3 μs. Preliminary repetition rate experiments are also carried out, which indicate that this pulse generator could work stably with the repetition rates of 30 Hz and 50 Hz. It can be concluded that this kind of all-solid-state microsecond-range quasi-square pulse generator can not only lower both the operating voltage of the primary windings and the saturable inductance of the secondary windings, thus ideally realizing the magnetic switch function of the fractional-turn ratio saturable pulse transformer, but also achieve a quasi-square pulse with high quality and fixed flat top after the modulation of a two-section anti-resonance network. This generator can be applied in areas of large power microwave sources, sterilization, disinfection, and wastewater treatment.
The effect of Ni addition on microstructure and soft magnetic properties of FeCoZrBCu nanocrystalline alloys
Authors: Fan Xingdu , Tang Yongtian , Shi Zhixiang , Jiang Mufeng , Shen Baolong
Published: March 2017

(Fe0.7Co0.3-xNix)88Zr7B4Cu1 nanocrystalline alloys were developed with the aim of improving the magnetic properties while keeping high Curie temperature (TC). It was revealed that Ni addition inhibited the precipitation of metastable fcc-(Fe,Co,Ni) phase hence increased thermal stability. Although the saturation magnetic flux density (Bs) showed a slight decrease, uniform nanostructure with small grain size and high volume fraction of crystals was formed with increasing Ni addition. As a result, the (Fe0.7Co0.3-xNix)88Zr7B4Cu1 nanocrystalline alloys exhibited excellent magnetic properties with a high Bs of 1.54-1.79 T, low coercivity (Hc) of 17-20 A/m and low core loss of 9.1-11.1 W/kg at 1 T and 400 Hz. The combination of high TC of 747-972 °C, low core loss as well as low material cost promised this FeCoNiZrBCu alloys broad application prospect at high temperature.
An inductance Fourier decomposition-based current-hysteresis control strategy for switched reluctance motors
Authors: Hua Wei , Qi Ji , Jia Meng
Published: March 2017

Switched reluctance machines (SRMs) have attracted extensive attentions due to the inherent advantages, including simple and robust structure, low cost, excellent fault-tolerance and wide speed range, etc. However, one of the bottlenecks limiting the SRMs for further applications is its unfavorable torque ripple, and consequently noise and vibration due to the unique doubly-salient structure and pulse-current-based power supply method. In this paper, an inductance Fourier decomposition-based current-hysteresis-control (IFD-CHC) strategy is proposed to reduce torque ripple of SRMs. After obtaining a nonlinear inductance-current-position model based Fourier decomposition, reference currents can be calculated by reference torque and the derived inductance model. Both the simulations and experimental results confirm the effectiveness of the proposed strategy.
High-efficiency in situ resonant inelastic x-ray scattering (iRIXS) endstation at the Advanced Light Source
Authors: Qiao Ruimin , Li Qinghao , Zhuo Zengqing , Sallis Shawn , Fuchs Oliver , Blum Monika , Weinhardt Lothar , Heske Clemens , Pepper John , Jones Michael , Brown Adam , Spucces Adrian , Chow Ken , Smith Brian , Glans Per-Anders , Chen Yanxue , Yan Shishen , Pan Feng , Piper Louis F. J. , Denlinger Jonathan , Guo Jinghua , Hussain Zahid , Chuang Yi-De , Yang Wanli
Published: March 2017

An endstation with two high-efficiency soft x-ray spectrographs was developed at Beamline 8.0.1 of the Advanced Light Source, Lawrence Berkeley National Laboratory. The endstation is capable of performing soft x-ray absorption spectroscopy, emission spectroscopy, and, in particular, resonant inelastic soft x-ray scattering (RIXS). Two slit-less variable line-spacing grating spectrographs are installed at different detection geometries. The endstation covers the photon energy range from 80 to 1500 eV. For studying transition-metal oxides, the large detection energy window allows a simultaneous collection of x-ray emission spectra with energies ranging from the O K-edge to the Ni L-edge without moving any mechanical components. The record-high efficiency enables the recording of comprehensive two-dimensional RIXS maps with good statistics within a short acquisition time. By virtue of the large energy window and high throughput of the spectrographs, partial fluorescence yield and inverse partial fluorescence yield signals could be obtained for all transition metal L-edges including Mn. Moreover, the different geometries of these two spectrographs (parallel and perpendicular to the horizontal polarization of the beamline) provide contrasts in RIXS features with two different momentum transfers.
DIASCoPE: Directly integrated acoustic system combined with pressure experiments—A new method for fast acoustic velocity measurements at high pressure
Authors: Whitaker Matthew L. , Baldwin Kenneth J. , Huebsch William R.
Published: March 2017

A new experimental system to measure elastic wave velocities in samples in situ under extreme conditions of pressure and temperature in a multi-anvil apparatus has been installed at Beamline 6-BM-B of the Advanced Photon Source at Argonne National Laboratory. This system allows for measurement of acoustic velocities via ultrasonic interferometry, and makes use of the synchrotron beam to measure sample densities via X-ray diffraction and sample lengths using X-radiographic imaging. This system is fully integrated into the automated software controls of the beamline and is capable of collecting robust data on elastic wave travel times in less than 1 s, which is an improvement of more than one to two orders of magnitude over existing systems. Moreover, this fast data collection time has been shown to have no effect on the obtained travel time results. This allows for more careful study of time-dependent phenomena with tighter snapshots in time of processes that would otherwise be lost or averaged out in other acoustic measurement systems.
Investigation of writing error in staggered heated-dot magnetic recording systems
Authors: Tipcharoen W. , Warisarn C. , Tongsomporn D. , Karns D. , Kovintavewat P.
Published: March 2017

To achieve an ultra-high storage capacity, heated-dot magnetic recording (HDMR) has been proposed, which heats a bit-patterned medium before recording data. Generally, an error during the HDMR writing process comes from several sources; however, we only investigate the effects of staggered island arrangement, island size fluctuation caused by imperfect fabrication, and main pole position fluctuation. Simulation results demonstrate that a writing error can be minimized by using a staggered array (hexagonal lattice) instead of a square array. Under the effect of main pole position fluctuation, the writing error is higher than the system without main pole position fluctuation. Finally, we found that the error percentage can drop below 10% when the island size is 8.5 nm and the standard deviation of the island size is 1 nm in the absence of main pole jitter.
Angular dependence of resonant absorption in FeCoB synthetic antiferromagnets
Authors: Adams Daniel J. , Khan Mohammad Asif , Poudyal Pratik , Spinu Leonard
Published: March 2017

Magnetization dynamics in a series of FeCoB/Ru/FeCoB coupled samples were investigated using a critical-curve-like approach through angular dependent broadband microwave absorption spectroscopy. Two samples were selected in this study, with ferromagnetic and antiferromagnetic coupling between the FeCoB layers. The dynamic critical curves (DCC) were obtained by systematically probing the angular-dependent FMR absorption at selected frequencies for both samples to show the effect of layer coupling both as a function of frequency and of angle. The DCC representation has the advantage of offering a direct and complete visual representation of anisotropy, interactions, and magnetization dynamics effects. The DCC is compared with static critical curve measured using a reversible susceptibility experiment.
The crystalline and magnetic properties of Zn doped strontium Z-type hexaferrite synthesized by polymerizable complex method
Authors: Lim Jung Tae , Shim In-Bo , Hahn Eun Joo , Kim Chul Sung
Published: March 2017

Polycrystalline samples of Sr3Co2-xZnxFe24O41 (x = 0.0, 0.5, 1.0, 1.5, 2.0) were synthesized by a polymerizable complex method. The crystallographic, and magnetic properties of samples were investigated using x-ray diffractometer (XRD), vibrating sample magnetometer (VSM), and Mössbauer spectroscopy. The crystal structures of all samples were determined to be hexagonal with the space group P63/mmc. The hysteresis curves under 10 kOe at 295 K showed that all samples were not saturated due to the high planar anisotropy of Sr ions. In addition, the coercivity (Hc) of samples decreased with increasing Zn ion contents. Mössbauer spectra of all samples were obtained at 295 K, and least-squares fitted below TC as six distinguishable sextets (4fIV, 4fIV*, 12kVI*, 4fVI*+ 4eIV, 12kVI, and 2dV + 2aVI + 4fVI + 4eVI).
Improved electrical properties of atomic layer deposited tin disulfide at low temperatures using ZrO2 layer
Authors: Lee Juhyun , Lee Jeongsu , Ham Giyul , Shin Seokyoon , Park Joohyun , Choi Hyeongsu , Lee Seungjin , Kim Juyoung , Sul Onejae , Lee Seungbeck , Jeon Hyeongtag
Published: March 2017

We report the effect of zirconium oxide (ZrO2) layers on the electrical characteristics of multilayered tin disulfide (SnS2) formed by atomic layer deposition (ALD) at low temperatures. SnS2 is a two-dimensional (2D) layered material which exhibits a promising electrical characteristics as a channel material for field-effect transistors (FETs) because of its high mobility, good on/off ratio and low temperature processability. In order to apply these 2D materials to large-scale and flexible electronics, it is essential to develop processes that are compatible with current electronic device manufacturing technology which should be conducted at low temperatures. Here, we deposited a crystalline SnS2 at 150 °C using ALD, and we then annealed at 300 °C. X-ray diffraction (XRD) and Raman spectroscopy measurements before and after the annealing showed that SnS2 had a hexagonal (001) peak at 14.9° and A1g mode at 313 cm−1. The annealed SnS2 exhibited clearly a layered structure confirmed by the high resolution transmission electron microscope (HRTEM) images. Back-gate FETs with SnS2 channel sandwiched by top and bottom ZrO2 on p++Si/SiO2 substrate were suggested to improve electrical characteristics. We used a bottom ZrO2 layer to increase adhesion between the channel and the substrate and a top ZrO2 layer to improve contact property, passivate surface, and protect from process-induced damages to the channel. ZTZ (ZrO2/SnS2/ZrO2) FETs showed improved electrical characteristics with an on/off ratio of from 0.39×103 to 6.39×103 and a mobility of from 0.0076 cm2/Vs to 0.06 cm2/Vs.
A direct electron detector for time-resolved MeV electron microscopy
Authors: Vecchione T. , Denes P. , Jobe R. K. , Johnson I. J. , Joseph J. M. , Li R. K. , Perazzo A. , Shen X. , Wang X. J. , Weathersby S. P. , Yang J. , Zhang D.
Published: March 2017

The introduction of direct electron detectors enabled the structural biology revolution of cryogenic electron microscopy. Direct electron detectors are now expected to have a similarly dramatic impact on time-resolved MeV electron microscopy, particularly by enabling both spatial and temporal jitter correction. Here we report on the commissioning of a direct electron detector for time-resolved MeV electron microscopy. The direct electron detector demonstrated MeV single electron sensitivity and is capable of recording megapixel images at 180 Hz. The detector has a 15-bit dynamic range, better than 30-μm spatial resolution and less than 20 analogue-to-digital converter count RMS pixel noise. The unique capabilities of the direct electron detector and the data analysis required to take advantage of these capabilities are presented. The technical challenges associated with generating and processing large amounts of data are also discussed.
Compressive mechanical response of graphene foams and their thermal resistance with copper interfaces
Authors: Park Wonjun , Li Xiangyu , Mandal Nirajan , Ruan Xiulin , Chen Yong P.
Published: March 2017

We report compressive mechanical response of graphene foams (GFs) and the thermal resistance (RTIM) between copper (Cu) and GFs, where GFs were prepared by the chemical vapor deposition method. We observe that Young’s modulus (EGF) and compressive strength (σGF) of GFs have a power law dependence on increasing density (ρGF) of GFs. The maximum efficiency of absorbed energy (ηmax) for all GFs during the compression is larger than ∼0.39. We also find that a GF with a higher ρGF shows a larger ηmax. In addition, we observe that the measured RTIM of Cu/GFs at room temperature with a contact pressure of 0.25 MP applied increases from ∼50 to ∼90 mm2 K/W when ρGF increases from 4.7 to 31.9 mg/cm3.
A high precision gas flow cell for performing in situ neutron studies of local atomic structure in catalytic materials
Authors: Olds Daniel , Page Katharine , Paecklar Arnold , Peterson Peter F. , Liu Jue , Rucker Gerald , Ruiz-Rodriguez Mariano , Olsen Michael , Pawel Michelle , Overbury Steven H. , Neilson James R.
Published: March 2017

Gas-solid interfaces enable a multitude of industrial processes, including heterogeneous catalysis; however, there are few methods available for studying the structure of this interface under operating conditions. Here, we present a new sample environment for interrogating materials under gas-flow conditions using time-of-flight neutron scattering under both constant and pulse probe gas flow. Outlined are descriptions of the gas flow cell and a commissioning example using the adsorption of N2 by Ca-exchanged zeolite-X (Na78−2xCaxAl78Si144O384,x ≈ 38). We demonstrate sensitivities to lattice contraction and N2 adsorption sites in the structure, with both static gas loading and gas flow. A steady-state isotope transient kinetic analysis of N2 adsorption measured simultaneously with mass spectrometry is also demonstrated. In the experiment, the gas flow through a plugged-flow gas-solid contactor is switched between N215 and N214 isotopes at a temperature of 300 K and a constant pressure of 1 atm; the gas flow and mass spectrum are correlated with the structure factor determined from event-based neutron total scattering. Available flow conditions, sample considerations, and future applications are discussed.
Flexible, highly sensitive pressure sensor with a wide range based on graphene-silk network structure
Authors: Liu Ying , Tao Lu-Qi , Wang Dan-Yang , Zhang Tian-Yu , Yang Yi , Ren Tian-Ling
Published: March 2017

In this paper, a flexible, simple-preparation, and low-cost graphene-silk pressure sensor based on soft silk substrate through thermal reduction was demonstrated. Taking silk as the support body, the device had formed a three-dimensional structure with ordered multi-layer structure. Through a simple and low-cost process technology, graphene-silk pressure sensor can achieve the sensitivity value of 0.4 kPa−1, and the measurement range can be as high as 140 kPa. Besides, pressure sensor can have a good combination with knitted clothing and textile product. The signal had good reproducibility in response to different pressures. Furthermore, graphene-silk pressure sensor can not only detect pressure higher than 100 kPa, but also can measure weak body signals. The characteristics of high-sensitivity, good repeatability, flexibility, and comfort for skin provide the high possibility to fit on various wearable electronics.
Estimation of plasma ion saturation current and reduced tip arcing using Langmuir probe harmonics
Authors: Boedo J. A. , Rudakov D. L.
Published: March 2017

We present a method to calculate the ion saturation current, Isat, for Langmuir probes at high frequency (>100 kHz) using the harmonics technique and we compare that to a direct measurement of Isat. It is noted that the Isat estimation can be made directly by the ratio of harmonic amplitudes, without explicitly calculating Te. We also demonstrate that since the probe tips using the harmonic method are oscillating near the floating potential, drawing little power, this method reduces tip heating and arcing and allows plasma density measurements at a plasma power flux that would cause continuously biased tips to arc. A multi-probe array is used, with two spatially separated tips employing the harmonics technique and measuring the amplitude of at least two harmonics per tip. A third tip, located between the other two, measures the ion saturation current directly. We compare the measured and calculated ion saturation currents for a variety of plasma conditions and demonstrate the validity of the technique and its use in reducing arcs.