bluuebunny/crossref_metadata_2025 huggingface dataset:
All‐optical reconfigurable multicast canonical logic units based on four‐wave mixing
Authors: Dong Wenchan , Hou Jie , Zhang Xinliang
Published: August 2017

Canonical logic units (CLUs) are basic building blocks for complex all‐optical logic operations, and multicast of CLUs can improve the computing capacity and operating flexibility. The authors thus propose and experimentally demonstrate all‐optical reconfigurable multicast two‐input CLUs (i.e. minterms) at 40 Gb/s by using four‐wave mixing in a single highly non‐linear fibre. Each type of CLUs with clear temporal waveform and wide eye opening is achieved in five parallel channels simultaneously. The extinction ratios are >10.3 dB, while the optical signal‐to‐noise ratios are >21 dB. Based on the demonstrated scheme, a method of realising simultaneous full set of two‐input logic operations is proposed and discussed. The proposed scheme can be extended to higher data rates and transferred to on‐chip platforms.
Numerical modelling of PCB planar inductors: impact of 3D modelling on high‐frequency copper loss evaluation
Authors: Taylor Laurent , Margueron Xavier , Le Menach Yvonnick , Le Moigne Philippe
Published: August 2017

Loss values are key parameters for designing high‐performance high‐frequency magnetic components for power electronics (PE) converters. With the increase of PE switching frequencies, copper losses have to be precisely quantified, ideally until some megahertz. In the literature, many 2D numerical simulations based on finite element analysis (FEA) are performed for such computations. 3D FEA studies of planar components are still limited because of modelling problems, computational resources and computing time. In this study, quantitative comparisons between 2D and 3D simulation results for planar inductors are achieved focusing on copper loss computation. Results are compared in terms of simulation performances and accuracy. The aim of the study is to highlight benefits of 2D and 3D FEA simulations in order to choose the appropriate model according to the studied problem.
Regioselective Hydroamination Using a Directed Nucleopalladation/Protodepalladation Strategy
Authors: Engle Keary , Gurak John
Published: August 2017

Alkene hydroamination is an attractive approach for converting alkenes into structurally complex amine products. Several different strategies have been pursued over the past few decades to achieve this historically challenging reaction. One of the key issues associated with this transformation is control of regioselectivity, which is particularly difficult for internal non-conjugated alkenes. Our group has recently found success using a removable bidentate auxiliary to control regioselectivity and stabilize the key nucleopalladated intermediate in a palladium(II)-catalyzed alkene hydroamination with N–H nucleophiles. This article describes the historical context for this work, the underlying conceptual logic, our results to date, and the future outlook.
Ammonium Iodide-Mediated Sulfenylation of 4-Hydroxycoumarins or 4-Hydroxyquinolinones with a Sulfonyl Chloride as a Sulfur Source
Authors: Guo Tao , Wei Xu-Ning
Published: August 2017

A novel ammonium iodide-induced sulfenylation of 4-hydroxycoumarins or 4-hydroxyquinolinones by using an aryl- or alkylsulfonyl chloride as the sulfur source gave a wide range of 3-sulfanyl-4-hydroxycoumarins or 3-sulfanyl-4-hydroxyquinolinones, respectively, in moderate to good yields. This method provides as a simple approach to the direct formation of C–S bonds, which is of high value and utility in the pharmaceutical industry.
Practical Preparation of Octa- and Tetrabromoperylene Diimides and Derivatives Thereof
Authors: Jozeliūnaitė Augustina , Striela Romualdas , Labanauskas Linas , Orentas Edvinas
Published: August 2017

A mild synthesis of fully brominated perylene dianhydride and diimides in one step from easily available unsubstituted precursors is presented. The partial reduction of ortho-bromo substituents with hydrazine hydrate allowed for a gram-scale synthesis of a valuable intermediate, 1,6,7,12-tetrabromoperylene diimide. Several new twisted fully core-substituted perylene diimide derivatives having sulfur, nitrogen, or oxygen substituents were synthesized using regioselective nucleophilic substitution reactions.
Intracardiac Thrombosis and Multiple Arterial Thromboembolism with Acute Limb Ischemia: A Rare Complication of Carbon Monoxide Intoxication
Authors: Benfor B. , Hajji R. , Bouarhroum A. , Lagdrori Y. , Boukatta Brahim , Elbouazzaoui Abderrahim , Kanjaa Nabil
Published: August 2017

Carbon monoxide (CO) poisoning is a very common reason for emergency ward admission, with symptoms varying from a simple headache and dizziness to severe neurological and cardiac impairment. We report here a rare clinical presentation of CO intoxication manifested by a severe cardiac impairment with intracardiac thrombus formation, acute limb ischemia, renal infarction, and carotid artery thrombosis. There have been initial reports of thromboembolic events in acute CO poisoning with intracardiac thrombosis being sparsely reported. Contrary to venous thromboembolism, arterial thromboembolism in CO poisoning seems to be extremely rare. To the best of our knowledge, this is the first report in recent literature of a combined intracardiac thrombosis and multiple arterial thromboembolism induced by CO poisoning.
Kommentar der Schriftleitung
Authors: Dietz Andreas
Published: August 2017

Liebe Leserinnen und Leser,genau, Sie lesen richtig: Ich bin der Neue.

Nach mehreren Jahren sehr erfolgreicher Schriftleitungstätigkeit durch meinen hochgeschätzten, lieben Kollegen Orlando Guntinas-Lichius habe
ich jetzt mit diesem Juli-Heft die federführende Schriftleitung innerhalb unseres aus Stefan Dazert, Orlando Guntinas-Lichius, Gerd Rasp und
mir bestehenden Schriftleitungsteams übernommen. Ich möchte bei dieser Gelegenheit Orlando Guntinas-Lichius im Namen der gesamten
Schriftleitung meinen herzlichen Dank für die ausgezeichnete Arbeit der letzten Jahre aussprechen.
Bilaterales hippocampales primäres ZNS-Lymphom: ungewöhnliche Differentialdiagnose eines rasch progredienten
dementiellen Syndroms
Authors: Weidauer Stefan , Hartmann Sylvia , Fabricius Jan
Published: August 2017

Vorgestellt wird ein rasch progredientes dementielles Syndrom bei einem 63-Jährigen infolge eines bilateralen hippocampalen primären
ZNS-Lymphoms. Da es sich bei sekundären Demenzformen um potentiell kausal behandelbare Ätiologien handelt, kommt der schnellen
Diagnosestellung eine entscheidende Bedeutung zu. Die richtungweisenden bildgebenden Aspekte insbesondere bei hippocampalen Prozessen werden
diskutiert.
Extracts of Terminalia sericea Enhance Cell Migratory Activity of Endothelial Hybrid and Fibroblast Cells In Vitro
Authors: Parkar Hafiza , Aiyegoro Olayinka , Steenkamp Paul , Steenkamp Vanessa
Published: August 2017

Terminalia sericea is a plant that has been used amongst others medicinally to treat wounds. The aim of this study was to assess the in vitro wound healing ability of T. sericea. Hot water, methanol, ethyl acetate, and hexane extracts were prepared. Thin layer chromatography (TLC) and ultra-performance liquid chromatography time of flight mass spectrometry (UPLC-TOF-MS) were used to determine the phytochemical classes and genus specific compounds present in the plant. Cytotoxicity was assessed in the SC-1 fibroblast and EA.hy926 endothelial hybrid cell lines using the sulforhodamine B assay. The effect of the extracts on cellular migration in both cell lines was assessed using the scratch assay. The major phytochemical classes detected in the extracts using TLC were alkaloids, coumarins, flavonoids, glycosides, phenolics, saponins, sterols, and terpenoids. The genus-specific compounds punicalagin, sericoside, anolignan B, and arjunic acid were identified in the extracts by means of UPLC-QTOF-MS. Cytotoxicity was not observed after 24 h of exposure and a generally low cytotoxic trend was noted after 72 h. A significant (p < 0.05) enhancement of cell migration in both cell lines was noted in the scratch assay. The wound healing ability of T. sericea is mainly attributed to the migratory and proliferative activity of the extracts responsible for the acceleration of wound closure. Isolation and individualized testing of the active compounds is warranted.
Habitual Minimalist Shod Running Biomechanics and the Acute Response to Running Barefoot
Authors: Tam Nicholas , Darragh Ian , Divekar Nikhil , Lamberts Robert
Published: August 2017

The aim of the study was to determine whether habitual minimalist shoe runners present with purported favorable running biomechanithat reduce running injury risk such as initial loading rate. Eighteen minimalist and 16 traditionally cushioned shod runners were assessed when running both in their preferred training shoe and barefoot. Ankle and knee joint kinetics and kinematics, initial rate of loading, and footstrike angle were measured. Sagittal ankle and knee joint stiffness were also calculated. Results of a two-factor ANOVA presented no group difference in initial rate of loading when participants were running either shod or barefoot; however, initial loading rate increased for both groups when running barefoot (p=0.008). Differences in footstrike angle were observed between groups when running shod, but not when barefoot (minimalist:8.71±8.99 vs. traditional: 17.32±11.48 degrees, p=0.002). Lower ankle joint stiffness was found in both groups when running barefoot (p=0.025). These findings illustrate that risk factors for injury potentially differ between the two groups. Shoe construction differences do change mechanical demands, however, once habituated to the demands of a given shoe condition, certain acute favorable or unfavorable responses may be moderated. The purported benefits of minimalist running shoes in mimicking habitual barefoot running is questioned, and risk of injury may not be attenuated.
Prediction Model of Serum Lithium Concentrations
Authors: Yoshida Kazunari , Uchida Hiroyuki , Suzuki Takefumi , Watanabe Masahiro , Yoshino Nariyasu , Houchi Hitoshi , Mimura Masaru , Fukuoka Noriyasu
Published: August 2017

Introduction Therapeutic drug monitoring is necessary for lithium, but clinical application of several prediction strategies is still limited because of insufficient predictive accuracy. We herein proposed a suitable model, using creatinine clearance (CLcr)-based lithium clearance (Li-CL).

Methods Patients receiving lithium provided the following information: serum lithium and creatinine concentrations, time of blood draw, dosing regimen, concomitant medications, and demographics. Li-CL was calculated as a daily dose per trough concentration for each subject, and the mean of Li-CL/CLcr was used to estimate Li-CL for another 30 subjects. Serum lithium concentrations at the time of sampling were estimated by 1-compartment model with Li-CL, fixed distribution volume (0.79 L/kg), and absorption rate (1.5/hour) in the 30 subjects.

Results One hundred thirty-one samples from 82 subjects (44 men; mean±standard deviation age: 51.4±16.0 years; body weight: 64.6±13.8 kg; serum creatinine: 0.78±0.20 mg/dL; dose of lithium: 680.2±289.1 mg/day) were used to develop the pharmacokinetic model. The mean±standard deviation (95% confidence interval) of absolute error was 0.13±0.09 (0.10–0.16) mEq/L.

Discussion Serum concentrations of lithium can be predicted from oral dosage with high precision, using our prediction model.
Back to balance: labour therapeutics and the depoliticisation of workplace distress
Authors: Davies James
Published: August 2017

This article assesses the rise in diverse workplaces of what the author terms “labour therapeutics”—the application of therapeutic ideas and interventions to the understanding and management of employee distress. By way of an inductive narrative analysis of five institutional proponents of labour therapeutics, it concludes that the interventions and understandings labour therapeutics promote, by either individualizing employee distress or reducing it to the micro-arrangements of the workplace, inadvertently depoliticize the problem of work for growing numbers of individuals and organizations in the contemporary work setting. Further research is requested to explicate the confluence between neo-liberal working objectives and the new forms of labour therapeutic governance now in rapid ascent. This article is published as part of a collection entitled ‘On balance: lifestyle, mental health and wellbeing’.
Scientific advice on the move: the UK mobile phone risk issue as a public experiment
Authors: Stilgoe Jack
Published: August 2017

The UK controversy over the health risks of mobile phones was at its peak around 1999–2000, at a time when policymakers were beginning to endorse moves towards greater openness in the practice of expert advice. One explanation for the subsequent calming of this controversy is that people’s sense of the benefits outweighed the minor uncertainties. However, this fails to explain the politics of mobile phone technology and, by positioning expert advice as neutral, offers no lessons for future expert practice. In this article, I argue that the mobile phones case can more productively be seen as one of public experiment. Rather than seeking closure, experts opened up the issue, made explicit previously obscured uncertainties and invited new research questions. In doing so, they remobilised previously static constructions of both science and public concern. This analysis challenges the distinction between science-as-expertise and science-as-experiment, with important implications for advisory practices and structures. This article is published as part of a thematic collection dedicated to scientific advice to governments.
Integrating social sciences and humanities in interdisciplinary research
Authors: Pedersen David Budtz
Published: August 2017

Recent attempts to integrate the social sciences and humanities (SSH) in funding for interdisciplinary research have been challenged by a number of barriers. In funding programmes, such as the EU Horizon 2020, the SSH are absent in most calls for contributions. This article revisits the main policy drivers for embedding SSH research in interdisciplinary research. By analysing recent policy initiatives, the article shows how policymakers across the world continue to be ambivalent regarding the role of the SSH. While many stakeholders acknowledge the need to integrate SSH research in solving key societal challenges, such as climate change, migration or national security, funding for SSH is limited and tends to focus on strategic interventions and instrumental solutions. By accounting for the diversity of interdisciplinary collaborations the article recommends a more context-sensitive approach to research funding, which acknowledges the heterogeneity and volatility of research across different knowledge environments. This article is published as part of a thematic collection on the concept of interdisciplinarity.
“Digitized Dysmorphia” of the female body: the re/disfigurement of the image
Authors: Coy-Dibley Isabelle
Published: August 2017

What has the digitization of female appearances, the altering of female bodies not only in media but individually among the general public through the use of apps, done to human sexual interactions and senses of self? Western society’s booming beauty and sex industries have hyper-sexualised society, over-selling the female image as a currency and commodity of desire. Yet, media no longer has exclusive power over regulating representations of female aesthetics. Nowadays, particularly in Western culture, we can digitally alter ourselves through Photoshop and apps such as Perfect365, producing our own notions of normativity. Not only do we critique our bodies in mirrors, but now we can digitize our dysmorphia by virtually modifying what we dislike, creating “perfect” selves instead. How do these online ideal images affect women’s relationships to their material bodies, do these digital images provide the freedom to express a self that would otherwise be overlooked or simply accentuate the disparity between female bodies and the images women feel they must embody? In positing the new term of “Digitised Dysmorphia”, I question whether transforming oneself into a virtual ideal, manipulating the image, is an act of dissidence, or a demonstration of how fully regulated we are by social norms, whereby digital modifications simply enable us to reach normative ideals. Alternatively, perhaps this enablement irrevocably changes definitions of “normativity” as we alter our relations to the body and image. Ultimately, this article offers an initial exploration into how this digitized dsymorphia affects our perception of self individually and as a collective society. This article is published as part of a collection dedicated to multi- and interdisciplinary perspectives on gender studies.
Exploring the scope of science advice: social sciences in the UK government
Authors: CG Cooper Adam
Published: August 2017

Science advice is normally seen in the context of physical science advice, and in particular in relation to the institutional position of “Chief Scientific Advisor” (CSA). This is true for the academic literature covering the science-policy interface, public administration, science and technology studies as well as most practitioner commentary. Very little literature exists on the provision of social science advice for public policy, insofar as this is framed in terms of individuals providing expertise within an institutional setting and role, as opposed to the provision of (social science) evidence within “evidence-based policy-making” or similar. This focus on the science advice has thus shaped the understanding of what a science advisor does, and what skills and expertise they are providing. Conventionally, this comprises an emphasis on significant knowledge in an area of expertise, a level of seniority and “eminence” to enable that knowledge to be influential and a degree of independence from those tasked with making policy decisions. Social science advice exists in the UK national policy-making context, but the mode of operation places a different emphasis and role on those providing such advice. I explore the nature of this role, using the conventional idea of the CSA as a point of departure to foreground points of similarity and difference. This exploration reveals a broader operating space for science advice than is conventionally understood and foregrounds particular tensions between relevance and influence, on the one hand, and scientific objectivity and independence, on the other. This article is published as part of a thematic collection dedicated to scientific advice to governments.
Solving the jitter problem in microwave compressed ultrafast electron diffraction instruments: Robust sub-50 fs cavity-laser phase stabilization
Authors: Otto M. R. , René de Cotret L. P. , Stern M. J. , Siwick B. J.
Published: August 2017

We demonstrate the compression of electron pulses in a high-brightness ultrafast electron diffraction instrument using phase-locked microwave signals directly generated from a mode-locked femtosecond oscillator. Additionally, a continuous-wave phase stabilization system that accurately corrects for phase fluctuations arising in the compression cavity from both power amplification and thermal drift induced detuning was designed and implemented. An improvement in the microwave timing stability from 100 fs to 5 fs RMS is measured electronically, and the long-term arrival time stability (>10 h) of the electron pulses improves to below our measurement resolution of 50 fs. These results demonstrate sub-relativistic ultrafast electron diffraction with compressed pulses that is no longer limited by laser-microwave synchronization.
Nonlinear response and bistability of driven ion acoustic waves
Authors: Akbari-Moghanjoughi M.
Published: August 2017

The hydrodynamic model is used to obtain a generalized pseudoforce equation through which the nonlinear response of periodically driven ion acoustic waves is studied in an electron-ion plasma with isothermal and adiabatic ion fluids. The pseudotime series, corresponding to different driving frequencies, indicates that nonlinearity effects appear more strongly for smaller frequency values. The existence of extra harmonic resonances in the nonlinear amplitude spectrum is a clear indication of the interaction of an external force with harmonic components of the nonlinear ion acoustic waves. It is shown that many plasma parameters significantly and differently affect the nonlinear resonance spectrum of ion acoustic excitations. A heuristic but accurate model for the foldover effect is used which quite satisfactorily predicts the bistability of driven plasma oscillations. It is remarked that the characteristic resonance peak of isothermal ion plasma oscillations appears at lower frequencies but is stronger compared to that of adiabatic ions. Comparison of the exact numerical results for fully nonlinear and approximate (weakly nonlinear) models indicates that a weakly nonlinear model exaggerates the hysteresis and jump phenomenon for higher values of the external force amplitude.
Band dependence of charge density wave in quasi-one-dimensional Ta2NiSe7 probed by orbital magnetoresistance
Authors: He Jiaming , Zhang Yiran , Wen Libin , Yang Yusen , Liu Jinyu , Wu Yueshen , Lian Hailong , Xing Hui , Wang Shun , Mao Zhiqiang , Liu Ying
Published: August 2017

Ta2NiSe7 is a quasi-one-dimensional (quasi-1D) transition-metal chalcogenide with Ta and Ni chain structures. An incommensurate charge-density wave (CDW) in this quasi-1D structure was well studied previously using tunnelling spectrum, X-ray, and electron diffraction, whereas its transport property and the relation to the underlying electronic states remain to be explored. Here, we report our results of the magnetoresistance (MR) on Ta2NiSe7. A breakdown of Kohler's rule is found upon entering the CDW state. Concomitantly, a clear change in curvature in the field dependence of MR is observed. We show that the curvature change is well described by the two-band orbital MR, with the hole density being strongly suppressed in the CDW state, indicating that the p orbitals from Se atoms dominate the change in transport through CDW transition.
Magnetic field-driven 3D-Heisenberg-like phase transition in single crystalline helimagnet FeGe
Authors: Xu Lisha , Fan Jiyu , Sun Weifeng , Zhu Yan , Hu Dazhi , Liu Jindong , Ji Yanda , Shi Daning , Yang Hao
Published: August 2017

Significant microscopic information about fundamental magnetic interactions of magnetic materials is probed via the critical behavior of paramagnetic-ferromagnetic phase transition. In this work, we demonstrate that the critical behavior of cubic single crystalline FeGe belongs to the isotropic 3D-Heisenberg universality class by measuring the field dependence of magnetic entropy change. The above transition is one of the magnetic field-driven phase transitions but has a feature of the crossover from first- to second-order phase transition. A phenomenological model based on the evolution of magnetic skyrmions was proposed to qualitatively understand the phase transition.
Drying and wetting transitions of a Lennard-Jones fluid: Simulations and density functional theory
Authors: Evans Robert , Stewart Maria C. , Wilding Nigel B.
Published: August 2017

We report a theoretical and simulation study of the drying and wetting phase transitions of a truncated Lennard-Jones fluid at a flat structureless wall. Binding potential calculations predict that the nature of these transitions depends on whether the wall-fluid attraction has a long ranged (LR) power law decay or is instead truncated, rendering it short ranged (SR). Using grand canonical Monte Carlo simulation and classical density functional theory, we examine both cases in detail. We find that for the LR case wetting is first order, while drying is continuous (critical) and occurs exactly at zero attractive wall strength, i.e., in the limit of a hard wall. In the SR case, drying is also critical but the order of the wetting transition depends on the truncation range of the wall-fluid potential. We characterize the approach to critical drying and wetting in terms of the density and local compressibility profiles and via the finite-size scaling properties of the probability distribution of the overall density. For the LR case, where the drying point is known exactly, this analysis allows us to estimate the exponent ν∥, which controls the parallel correlation length, i.e., the extent of vapor bubbles at the wall. Surprisingly, the value we obtain is over twice that predicted by mean field and renormalization group calculations, despite the fact that our three dimensional system is at the upper critical dimension where mean field theory for critical exponents is expected to hold. Possible reasons for this discrepancy are discussed in the light of fresh insights into the nature of near critical finite-size effects.
Influence of sample preparation on the transformation of low-density to high-density amorphous ice: An explanation based on the potential energy landscape
Authors: Giovambattista Nicolas , Starr Francis W. , Poole Peter H.
Published: August 2017

Experiments and computer simulations of the transformations of amorphous ices display different behaviors depending on sample preparation methods and on the rates of change of temperature and pressure to which samples are subjected. In addition to these factors, simulation results also depend strongly on the chosen water model. Using computer simulations of the ST2 water model, we study how the sharpness of the compression-induced transition from low-density amorphous ice (LDA) to high-density amorphous ice (HDA) is influenced by the preparation of LDA. By studying LDA samples prepared using widely different procedures, we find that the sharpness of the LDA-to-HDA transformation is correlated with the depth of the initial LDA sample in the potential energy landscape (PEL), as characterized by the inherent structure energy. Our results show that the complex phenomenology of the amorphous ices reported in experiments and computer simulations can be understood and predicted in a unified way from knowledge of the PEL of the system.
Drift-wave stability in the field-reversed configuration
Authors: Lau C. K. , Fulton D. P. , Holod I. , Lin Z. , Binderbauer M. , Tajima T. , Schmitz L.
Published: August 2017

Gyrokinetic simulations of C-2-like field-reversed configuration (FRC) find that electrostatic drift-waves are locally stable in the core. The stabilization mechanisms include finite Larmor radius effects, magnetic well (negative grad-B), and fast electron short circuit effects. In the scrape-off layer (SOL), collisionless electrostatic drift-waves in the ion-to-electron-scale are destabilized by electron temperature gradients due to the resonance with locally barely trapped electrons. Collisions can suppress this instability, but a collisional drift-wave instability still exists at realistic pressure gradients. Simulation results are in qualitative agreement with C-2 FRC experiments. In particular, the lack of ion-scale instability in the core is not inconsistent with experimental measurements of a fluctuation spectrum showing a depression at ion-scales. The pressure gradient thresholds for the SOL instability from simulations are also consistent with the critical gradient behavior observed in experiments.
Pumped thermal grid storage with heat exchange
Authors: Laughlin Robert B.
Published: August 2017

A thermal heat-pump grid storage technology is described based on closed-cycle Brayton engine transfers of heat from a cryogenic storage fluid to molten solar salt. Round-trip efficiency, computed as a function of turbomachinery polytropic efficiency and total heat exchanger steel mass, is found to be competitive with that of pumped hydroelectric storage. The cost per engine watt and cost per stored joule based are estimated based on the present-day prices of power gas turbines and market prices of steel and nitrate salt. Comparison is made with electrochemical and mechanical grid storage technologies.
The long persistence length of model tubules
Authors: Stevens Mark J.
Published: August 2017

Young’s elastic modulus and the persistence length are calculated for a coarse-grained model of tubule forming polymers. The model uses a wedge shaped composite of particles that previously has been shown to self-assemble into tubules. These calculations demonstrate that the model yields very large persistence lengths (corresponding to 78–126 μm) that are comparable to that observed in experiments for the microtubule lengths accessible to the calculations. The source for the stiffness is the restricted rotation of the monomer due to the excluded volume interactions between bonded macromolecular monomers as well as the binding between monomers. For this reason, large persistence lengths are common in tubule systems with a macromolecule as the monomer. The persistence length increases linearly with increased binding strength in the filament direction. No dependence in the persistence length is found for varying the tubule pitch for geometries with the protofilaments remaining straight.
Analytic energy gradients for the coupled-cluster singles and doubles with perturbative triples method with the density-fitting approximation
Authors: Bozkaya Uğur , Sherrill C. David
Published: August 2017

An efficient implementation of analytic gradients for the coupled-cluster singles and doubles with perturbative triples [CCSD(T)] method with the density-fitting (DF) approximation, denoted as DF-CCSD(T), is reported. For the molecules considered, the DF approach substantially accelerates conventional CCSD(T) analytic gradients due to the reduced input/output time and the acceleration of the so-called “gradient terms”: formation of particle density matrices (PDMs), computation of the generalized Fock-matrix (GFM), solution of the Z-vector equation, formation of the effective PDMs and GFM, back-transformation of the PDMs and GFM, from the molecular orbital to the atomic orbital (AO) basis, and computation of gradients in the AO basis. For the largest member of the molecular test set considered (C6H14), the computational times for analytic gradients (with the correlation-consistent polarized valence triple-ζ basis set in serial) are 106.2 [CCSD(T)] and 49.8 [DF-CCSD(T)] h, a speedup of more than 2-fold. In the evaluation of gradient terms, the DF approach completely avoids the use of four-index two-electron integrals. Similar to our previous studies on DF-second-order Møller–Plesset perturbation theory and DF-CCSD gradients, our formalism employs 2- and 3-index two-particle density matrices (TPDMs) instead of 4-index TPDMs. Errors introduced by the DF approximation are negligible for equilibrium geometries and harmonic vibrational frequencies.
Compartmentalized embryoid body culture for induction of spatially patterned differentiation
Authors: Kaneda Shohei , Kawada Jiro , Akutsu Hidenori , Ichida Justin , Ikeuchi Yoshiho , Fujii Teruo
Published: August 2017

We developed a compartmentalized culture system of single embryoid bodies (EBs) utilizing a through-hole on a membrane to induce spatially patterned differentiation. An EB derived from mouse pluripotent stem cells was immobilized on the through-hole. By introducing a stem cell maintenance medium and a differentiation medium into upper and lower culture compartments, respectively, a localized differentiated state was achieved only in the lower part of EB, which is exposed to the medium in the lower compartment. This system may enable us to reconstruct complex tissues and to recapitulate developmental processes using EBs.
The dissociation and recombination rates of CH4 through the Ni(111) surface: The effect of lattice motion
Authors: Wang Wenji , Zhao Yi
Published: August 2017

Methane dissociation is a prototypical system for the study of surface reaction dynamics. The dissociation and recombination rates of CH4 through the Ni(111) surface are calculated by using the quantum instanton method with an analytical potential energy surface. The Ni(111) lattice is treated rigidly, classically, and quantum mechanically so as to reveal the effect of lattice motion. The results demonstrate that it is the lateral displacements rather than the upward and downward movements of the surface nickel atoms that affect the rates a lot. Compared with the rigid lattice, the classical relaxation of the lattice can increase the rates by lowering the free energy barriers. For instance, at 300 K, the dissociation and recombination rates with the classical lattice exceed the ones with the rigid lattice by 6 and 10 orders of magnitude, respectively. Compared with the classical lattice, the quantum delocalization rather than the zero-point energy of the Ni atoms further enhances the rates by widening the reaction path. For instance, the dissociation rate with the quantum lattice is about 10 times larger than that with the classical lattice at 300 K. On the rigid lattice, due to the zero-point energy difference between CH4 and CD4, the kinetic isotope effects are larger than 1 for the dissociation process, while they are smaller than 1 for the recombination process. The increasing kinetic isotope effect with decreasing temperature demonstrates that the quantum tunneling effect is remarkable for the dissociation process.
Toward reliable modeling of S-nitrosothiol chemistry: Structure and properties of methyl thionitrite (CH3SNO), an S-nitrosocysteine model
Authors: Khomyakov Dmitry G. , Timerghazin Qadir K.
Published: August 2017

Methyl thionitrite CH3SNO is an important model of S-nitrosated cysteine aminoacid residue (CysNO), a ubiquitous biological S-nitrosothiol (RSNO) involved in numerous physiological processes. As such, CH3SNO can provide insights into the intrinsic properties of the —SNO group in CysNO, in particular, its weak and labile S—N bond. Here, we report an ab initio computational investigation of the structure and properties of CH3SNO using a composite Feller-Peterson-Dixon scheme based on the explicitly correlated coupled cluster with single, double, and perturbative triple excitations calculations extrapolated to the complete basis set limit, CCSD(T)-F12/CBS, with a number of additive corrections for the effects of quadruple excitations, core-valence correlation, scalar-relativistic and spin-orbit effects, as well as harmonic zero-point vibrational energy with an anharmonicity correction. These calculations suggest that the S—N bond in CH3SNO is significantly elongated (1.814 Å) and has low stretching frequency and dissociation energy values, νS—N = 387 cm−1 and D0 = 32.4 kcal/mol. At the same time, the S—N bond has a sizable rotation barrier, △E0≠ = 12.7 kcal/mol, so CH3SNO exists as a cis- or trans-conformer, the latter slightly higher in energy, △E0 = 1.2 kcal/mol. The S—N bond properties are consistent with the antagonistic nature of CH3SNO, whose resonance representation requires two chemically opposite (antagonistic) resonance structures, CH3—S+=N—O− and CH3—S−/NO+, which can be probed using external electric fields and quantified using the natural resonance theory approach (NRT). The calculated S—N bond properties slowly converge with the level of correlation treatment, with the recently developed distinguished cluster with single and double excitations approximation (DCSD-F12) performing significantly better than the coupled cluster with single and double excitations (CCSD-F12), although still inferior to the CCSD(T)-F12 method that includes perturbative triple excitations. Double-hybrid density functional theory (DFT) calculations with mPW2PLYPD/def2-TZVPPD reproduce well the geometry, vibrational frequencies, and the S—N bond rotational barrier in CH3SNO, while hybrid DFT calculations with PBE0/def2-TZVPPD give a better S—N bond dissociation energy.
Continuous-frequency measurements of high-intensity microwave electric fields with atomic vapor cells
Authors: Anderson D. A. , Raithel G.
Published: August 2017

We demonstrate continuous-frequency electric field measurements of high-intensity microwaves via optical spectroscopy in a small atomic vapor cell. The spectroscopic response of a room-temperature rubidium atomic vapor in a glass cell is investigated and employed for absolute measurements of Ka-band microwave electric fields from ∼200 V/m to >1 kV/m over a continuous frequency range of ±1 GHz (15% band coverage). It is established that in strong microwave fields, frequency-specific spectral features allow for electric field measurements over a large continuous frequency range.
Characterisation of elastic turbulence in a serpentine micro-channel
Authors: Souliès Antoine , Aubril Julien , Castelain Cathy , Burghelea Teodor
Published: August 2017

A systematic experimental investigation of the onset, development, and statistical and scaling properties of elastic turbulence in a curvilinear micro-channel of a dilute solution of a high molecular weight polymer is presented. By measurements of time series of high spatial resolution flow fields performed over a time 320 times longer than the average relaxation, we show that the transition to elastic turbulence occurs via an imperfect bifurcation. Slightly above the onset of the primary elastic instability, rare events manifested through a local deceleration of the flow are observed. By measurements of the spatial distributions and statistics of the second invariant of the rate of strain tensor, we show that the main prediction of the theory regarding the saturation of root mean square of fluctuations of the velocity gradients is qualitatively verified though a quantitative agreement could not be found. A systematic analysis of the statistics of the fluctuations of flow fields in terms of spatial and temporal correlations, power spectra, and probability distributions is presented. The scaling properties of structure functions of the increments of the velocity gradients are discussed. Our experimental findings call for further developments of the theory of elastic turbulence in bounded flow channels.
Surface plasmon enhanced Si-based BIB terahertz detectors
Authors: Zhu He , Weng Zeping , Zhu Jiaqi , Xu Jintao , Wu Huizhen , Dai Ning
Published: August 2017

We integrate two dimensional hole arrays (2DHAs),a plasmonic structure, into silicon based blocked impurity band (BIB) terahertz detectors. The photoresponse of the BIB device without 2DHA covers a broad spectral range from 31 μm (9.68 THz) to 15 μm (20 THz). Although 80% of the active region is covered with a metal film in the surface plasmon (SP)-enhanced device, its absolute photoresponse is 120% higher than that of the reference device at the peak wavelength. We further find that the SP-enhanced device presents about 8-fold enhancement in comparison with the reference device at λ = 30.7 μm (9.77 THz) that is beyond the SP resonance. By an energy band model and electromagnetic field simulation, we discover that the photoresponse enhancement at both the resonance wavelength and the non-resonance wavelength is related to a strong confined electromagnetic field at the interface of the 2DHAs and active region.
Statistical properties of the rovibrational bound levels for Ar2Kr
Authors: Wu Meng-Shan , Han Hui-Li , Yao Cui , He Xiao-Rong , Zhang Jun-Yi , Shi Ting-Yun
Published: August 2017

We calculate the rovibrational bound levels with total angular momentum J = 0, 1 of 40Ar284Kr trimer using the slow variable discretization method combined with the finite-element method-discrete variable representation basis. The statistical distributions of the rovibrational levels for JΠ=0e, 1e, and 1o symmetries are presented and the effects of the Axilrod-Teller potential term are considered. For the 0e and 1e symmetries, the Axilrod-Teller term makes the spectra become fully chaotic. However, for the 1o symmetry, statistical properties depend mainly on the coupling between K = 0 and K = 1 and the Axilrod-Teller term has a small effect.
Existence and concentration of positive solutions for fractional nonlinear Schrödinger equation with critical growth
Authors: Shang Xudong , Zhang Jihui
Published: August 2017

In this paper, we study the existence and concentration behavior of positive solutions for the following critical fractional nonlinear Schrödinger equation ℏ2s(−Δ)su+V(x)u=u2s*−1+f(u) with u(x)>0, u∈Hs(RN), where ℏ is a positive parameter, s∈(0,1), N>2s and 2s*=2NN−2s are the fractional critical exponent, and f is a continuous subcritical nonlinearity. Suppose the potential V(x) satisfying infRNV(x)>0 and there exists an open bounded domain Ω of RN such that infx∈∂ΩV(x)>infx∈ΩV(x)=m0. By using variational methods, we show that the problem has a positive bound state solution which concentrates around a local minimum point of V as ℏ tends to zero. Moreover, we investigate regularity and decay properties of the solution.
A lower bound for the BCS functional with boundary conditions at infinity
Authors: Deuchert Andreas
Published: August 2017

We consider a many-body system of fermionic atoms interacting via a local pair potential and subject to an external potential within the framework of Bardeen-Cooper-Schrieffer (BCS) theory. We measure the free energy of the whole sample with respect to the free energy of a reference state which allows us to define a BCS functional with boundary conditions at infinity. Our main result is a lower bound for this energy functional in terms of expressions that typically appear in Ginzburg-Landau functionals.
A new approach for mitigating blade passing effects and power quality improvement of grid-connected DFIG wind turbine
Authors: Mahvash Hossein , Taher Seyed Abbas , Rahimi Mohsen , Shahidehpour Mohammad
Published: August 2017

Blade passing effects (BPEs) including tower shadow and wind shear cause 3P oscillations on mechanical and electrical active power profiles in a grid-connected doubly fed induction generator (DFIG) wind turbine. The basic aim of this paper was to present an effective method to mitigate the destructive problems caused by BPEs and to smooth the active power profile in DFIG, in addition to mitigate 3P oscillations on the voltage profile of the weak connected grid. The proposed approach was based on design and application of a band pass filter (BPF) to the external loop of DFIG active power control in the rotor side converter to remove 3P oscillations of the rotor reference current at mean wind speeds of 9–16 m/s. At high wind speeds, the proposed BPF is simultaneously used in the pitch angle control loop of DFIG to reduce 3p pulsations in the pitch angle profile. The simulation process is carried out at multiple wind speeds considering the new model of BPEs, which was derived to model these phenomena with a simple equation. The proposed model could be effective to analyze the DFIG performance, suitably via considering the adverse effects of tower shadow and wind shear, and to study the grid power quality problems. Simulation results are obtained for DFIG active power and grid RMS voltage profiles. These results validated the usefulness of the proposed method to improve the DFIG performance by smoothing the produced active power profile. Moreover, the periodic pulsations of the grid voltage profile are mitigated to enhance the grid power quality.
Turbulent energy dissipation rate in a tilting flume with a highly rough bed
Authors: Coscarella F. , Servidio S. , Ferraro D. , Carbone V. , Gaudio R.
Published: August 2017

Turbulent flows on highly rough beds, such as those occurring in natural watercourses, represent a longstanding and fascinating problem of hydraulics, motivating in the past few decades huge research on new models of turbulence. In this work, laboratory experiments are presented on a stream flowing on a heterogeneous pebble bed with varying slope. The analysis of the flow speed puts in evidence a clear inertial range, where the Kolmogorov 4/5-law for the streamwise velocity spatial increments holds. The law is used for a systematic estimation of the turbulent kinetic energy dissipation rate 𝜖, here measured for three different bed slopes and hence for three different shear Reynolds numbers. The experiments presented here suggest that small scale turbulence has properties similar to the classical picture of homogeneous universal turbulence invoked by the Kolmogorov theory.
Conduction mechanism change with transport oxide layer thickness in oxide hetero-interface diode
Authors: Nam Bu-il , Park Jong Seo , Lim Keon-Hee , Ahn Yong-keon , Lee Jinwon , Park Jun-woo , Cho Nam-Kwang , Lee Donggun , Lee Han-Bo-Ram , Kim Youn Sang
Published: August 2017

An effective and facile strategy is proposed to demonstrate an engineered oxide hetero-interface of a thin film diode with a high current density and low operating voltage. The electrical characteristics of an oxide hetero-interface thin film diode are governed by two theoretical models: the space charge-limited current model and the Fowler-Nordheim (F-N) tunneling model. Interestingly, the dominant mechanism strongly depends on the insulator thickness, and the mechanism change occurs at a critical thickness. This paper shows that conduction mechanisms of oxide hetero-interface thin film diodes depend on thicknesses of transport oxide layers and that current densities of these can be exponentially increased through quantum tunneling in the diodes with the thicknesses less than 10 nm. These oxide hetero-interface diodes have great potential for low-powered transparent nanoscale applications.
A new chaotic oscillator with free control
Authors: Li Chunbiao , Sprott Julien Clinton , Akgul Akif , Iu Herbert H. C. , Zhao Yibo
Published: August 2017

A novel chaotic system is explored in which all terms are quadratic except for a linear function. The slope of the linear function rescales the amplitude and frequency of the variables linearly while its zero intercept allows offset boosting for one of the variables. Therefore, a free-controlled chaotic oscillation can be obtained with any desired amplitude, frequency, and offset by an easy modification of the linear function. When implemented as an electronic circuit, the corresponding chaotic signal can be controlled by two independent potentiometers, which is convenient for constructing a chaos-based application system. To the best of our knowledge, this class of chaotic oscillators has never been reported.
Ion induced stress relaxation in dense sputter-deposited DLC thin films
Authors: Aijaz Asim , Kubart Tomas
Published: August 2017

Deposition of high-density and low-stress hydrogen-free diamond like carbon (DLC) thin films is demonstrated using a pulsed ionized sputtering process. This process is based on high power impulse magnetron sputtering, and high C ionization is achieved using Ne as the sputtering gas. The intrinsic compressive stress and its evolution with respect to ion energy and ion flux are explained in terms of the compressive stress based subplantation model for DLC growth by Davis. The highest mass density was ∼2.7 g/cm3, and the compressive stresses did not exceed ∼2.5 GPa. The resulting film stresses are substantially lower than those achieved for the films exhibiting similar mass densities grown by filtered cathodic vacuum arc and pulsed laser deposition methods. This unique combination of high mass density and low compressive stress is attributed to the ion induced stress relaxation during the pulse-off time which corresponds to the post thermal spike relaxation timescales. We therefore propose that the temporal ion flux variations determine the magnitude of the compressive stress observed in our films.