bluuebunny/crossref_metadata_2025 huggingface dataset:
Developments for collective Thomson scattering equipment with a sub-THz gyrotron in LHD
Authors: Saito Teruo , Tatematsu Yoshinori , Yamaguchi Yuusuke , Fukunari Masafumi , Hirobe Takumi , Shinbayashi Ryushi , Tanaka Shunsuke , Ohkubo Kunizo , Kubo Shin , Shimozuma Takashi , Tanaka Kenji , Nishiura Masaki
Published: March 2019

Plan of collective Thomson scattering (CTS) experiment for the Large Helical Device (LHD) in NIFS with a 303 GHz gyrotron is under way. Use of a sub-THz gyrotron expands the CTS-applicable region of plasma parameters. In LHD, sub-THz CTS can be applied to the high density operation region, plasmas with impurity hole, etc. Moreover, sub-THz CTS is expected to be free from ECE noise. Its “collective” use with 77 GHz and 154 GHz CTS will compose a powerful diagnostic system. A high power sub-THz gyrotron with a frequency of 303 GHz has been developed. Its maximum power is 320 kW. It oscillates in pulse mode and the maximum pulse width is around 100 μs, which is sufficient for use in CTS experiments. A whispering gallery mode TE22,2was adopted for this gyrotron to avoid mode competition. Careful frequency measurement has proved purely single mode oscillation of the TE22,2mode including turn-on and turn-off phases of the oscillation pulse. This is consistent with mode competition calculations taking account of a finite voltage rise time. A low loss transmission line is necessary for CTS. We have two possibilities. One is a new line with 1.25 inch corrugated waveguides that are optimized for the 300 GHz band. Transmission test with the 303 GHz gyrotron has been carried out and a sufficiently low loss coefficient has been confirmed. The other is to use an existing line with 3.5 inch corrugated waveguides for lower frequencies such as 77 GHz and 154 GHz. Transmission test has been carried out with the 303 GHz gyrotron and a sufficiently low loss coefficient has been confirmed also for 3.5 inch corrugated waveguides. An existing line with 3.5 inch corrugated waveguides will be used in the initial phase of 303 GHz CTS experiment.
Development of a correlation ECE radiometer for electron temperature fluctuation measurements in Heliotron J
Authors: Weir Gavin M. , Nagasaki Kazunobu , Zhu Jinxiang , Luo Maoyuan , Okada Hiroyuki , Minami Takashi , Kado Shinichiro , Kobayashi Shinji , Yamamoto Satoshi , Ohshima Shinsuke , Konoshima Shigeru , Nakamura Yuji , Ishizawa Akihiro , Lu Xiang-xun , Zang Linge , Marushchenko Nikolai , Yoshimura Yasuo , Mizuuchi Tohru
Published: March 2019

A radial correlation ECE radiometer diagnostic has been developed for electron temperature fluctuation measurements in the helical-axis heliotron device, Heliotron J. The radiometer consists of two heterodyne detection systems. One system scans the frequency of a local oscillator from 52 to 64 GHz with a single intermediate frequency filter, and the second system has a fixed frequency, 56 GHz local oscillator with four intermediate frequency filters. This frequency range covers measurement positions spanning from the plasma core to the half radius. Laboratory tests indicate that each system has narrow intermediate frequency bandwidth and high-sensitivity over a large dynamic range. During plasma experiments with NBI heating, radiation temperature fluctuation measured by the CECE radiometer decrease with increasing ECCD commensurate with previous measurements of energetic particle driven modes on Heliotron J.
Design and Performance of Microwave Components for ECH and ECE Applications at General Atomics
Authors: Anderson James , Doane John , Moeller Charles , Grunloh Howard , O’Neill Raymond , Brookman Michael , Smiley Matthew , Su David
Published: March 2019

This paper provides an overview of high power components for the application of Electron Cyclotron Heating transmission lines, and broadband devices for Electron Cyclotron Emission detection systems. The unique fabrication and assembly challenges are discussed, particularly in the context of ITER. The ITER ECH system will require robust, vacuum-compatible components such as polarizers, dummy loads, and switches that are sufficiently cooled to withstand 1 MW for 3,600 seconds. These elements, along with overmoded corrugated waveguide, are necessary to form transmission lines with efficiencies of 90%, and 90% transmitted HE11mode purity. Recent high power test results are summarized and scaled from the 63.5 mm internal diameter design to the 50 mm diameter version that will be used for ITER. Elements designed for Electron Cyclotron Emission detection and reflectometry systems are discussed, such as frequency filters and polarization rotators. The large frequency operating range of corrugated waveguide is exploited for such applications. The application of additive manufacturing technology towards both low and high power components is considered as a promising new area of development.
Recent progress of the development of a long pulse 140GHz ECRH system on EAST
Authors: Xu Handong , Wang Xiaojie , Zhang Jian , Liu Fukun , Huang Yiyun , Shan Jiafang , Xu Weiye , Li Miaohui , Lohr J. , Gorelov Y.A. , Anderson J.P. , Zhang Yang , Wu Dajun , Hu Huaichuan , Yang Yong , Feng Jianqiang , Tang Yunying , Li Bo , Ma Wendong , Wu Zege , Wang Jian , Zhang Liyuan , Guo Fei , Sun Haozhang , Yan Xinsheng ,   EAST Team
Published: March 2019

A long pulse ECRH system with a goal of 140GHz 4MW 100~1000s has been developed to meet the requirement of steady-state operation on EAST. Gycom gyrotrons are employed in the No.1 and No.3 systems, CPI gyrotrons are used in the No.2 and No.4 systems. The development of the two Gycom gyrotron systems has been finished. The first short pulse EC wave injection has been demonstrated successfully during the EAST 2015 Spring campaign. In the commissioning and operation towards steady-state operation, 0.4MW 100s has been injected to plasma successfully by using the No.1 system, 4.7keV 102s L-mode and 102s H-mode plasma have been achieved on EAST with the help of ECRH. Recently, a longest pulse of 0.55MW 1000s has been obtained based on calorimetric dummy load measurements on the No.3 gyrotron. The No.2 gyrotron also has been installed and partially tested, 500kW 80s has been demonstrated in the dummy load. The remaining No.4 gyrotron will be ready to test in 2018 or 2019. The whole 4MW system will be completed within two years. The 400s fully non-inductive H-mode operation would be expected in the next four years in the condition of fully tungsten diverter on EAST.
Improved Simulation of Quasi-Optical Launchers for High Power Gyrotrons with Smoothing Algorithm
Authors: Jin Jianbo , Gantenbein Gerd , Rzesnicki Tomasz , Thumm Manfred , Jelonnek John
Published: March 2019

Numerically optimized launchers for the quasi-optical output coupler of high power gyrotrons have been developed to provide RF beams with high Gaussian mode content. Generally, the profiles of numerically optimized launchers are quite complicated, so the improvement of their tolerance to fabrication errors is very important. In order to reduce the stray radiation generated by launchers with quite complicated wall profile, and also to reduce their sensitivity to fabrication errors, a method for the smoothing of the numerically optimized launcher wall has been developed at KIT, which is based on the spectrum reconstruction approach. As an example, a launcher designed for the KIT TE34,19-mode, 2 MW CW coaxial-cavity gyrotron has been investigated.
Comparative studies of various types of transmission lines in the frequency range 70 GHz 1 THz for ITER ECE diagnostic
Authors: Kumar Ravinder , Danani S. , Pandya H.K.B. , Vaghashiya P. , Udintsev V.S. , Taylor G. , Austin M.E. , Kumar Vinay
Published: March 2019

In ITER, an Electron Cyclotron Emission (ECE) diagnostic is planned to measure the electron temperature by measuring the cyclotron radiation in the frequency range of 70-1000 GHz. The cyclotron radiation is usually of low power and needs to be transported with low attenuation over a long distance of ~ 43 m, through a suitable transmission system. Pertaining to long distance, the transmission system will consist of straight waveguide sections, miter bends and waveguide joints. Low power, low loss transmission in a broadband frequency range over long distance makes the design of the transmission system challenging. To arrive at a suitable transmission system, attenuation measurements of three types of transmission lines (TLs) have been performed i.e. circular smooth walled, corrugated and dielectric coated waveguide. A polarizing Michelson interferometer based on Martin-Puplett design has been used to measure the spectrum from waveguide set ups and liquid nitrogen has been used as the black body radiation source. The measured spectrum shows atmospheric water vapour absorption lines in all types of TLs. The preliminary measurement shows that the attenuation of smooth walled waveguide is found to be comparable to corrugated waveguide up to ~ 600GHz and better than corrugated waveguide above 600 GHz for the chosen set of experimental conditions. Further, to avoid water absorption lines, a smooth walled TL is evacuated up to rough vacuum (~10-2mbar) and it was observed that the attenuation is decreased and overall transmission is improved.
Overview on recent progress in magnetron injection gun theory and design for high power gyrotrons
Authors: Pagonakis Ioannis , Alberti Stefano , Avramidis Konstantinos , Legrand Francois , Gantenbein Gerd , Genoud Jérémy , Hogge Jean-Philippe , Illy Stefan , Ioannidis Zisis , Kalaria Parth , Piosczyk Bernhard , Ruess Sebastian , Ruess Tobias , Rzesnicki Tomasz , Tran Minh-Quang , Tran† Trach-Minh , Thumm Manfred , Vomvoridis Ioannis , Jelonnek John
Published: March 2019

The magnetron injection gun (MIG) is one of the most critical subcomponents in gyrotrons. The electron beam, which has the primary role on the gyrotron operation, is generated and configured at this part of the tube. The electron beam properties determine the excitation mode in the cavity, the power of the generated microwaves and the gyrotron efficiency. The operation of MIGs could be influenced by several factors such as trapped electrons, manufacturing tolerances, roughness of the emitter ring, emitter temperature inhomogeneity, electron beam neutralization effect, etc. The influence of many of these factors on the electron beam quality has been systematically investigated during the last years. Several novelties have been proposed in order to limit the influence of these factors on the gyrotron operation. In particular, new design criteria have been proposed for the suppression of electron trapping mechanisms, a new type of the emitter ring has been proposed to minimize the influence of the manufacturing tolerances and edge effects on the beam quality, alternative MIG design approaches have been proposed, etc. An overview of all these works will be presented here.
Conceptual design of CFETR ECRH equatorial launcher and upper launcher
Authors: Tang Yunying , Liu Fukun , Wang Xiaojie , Wei Wei , Zhang Liyuan , Xu Handong , Wu Dajun , Xu Weiye , Wang Jian
Published: March 2019

The Electron Cyclotron Resonance Heating (ECRH) system of China Fusion Engineering Test Reactor (CFETR) is designed to inject 20 MW RF power into the plasma for heating and current drive (H&CD) applications. The ECRH system consists of 20 gyrotrons, the associated power supplies, the transmission lines and one launcher. In order to compare the launcher performance from equatorial and upper ports, two types of launcher are designed in this paper. In equatorial launcher (EL), twenty in-vessel transmission lines are divided into four groups. Every five gaussian beams from in-vessel transmission lines face one fixed focusing mirror and one steering mirror. All gaussian beams are injected into the plasma with optimal toroidal and poloidal angles calculated by C3PO/LUKE code. In upper launcher (UL), twenty-one transmission lines are supposed and divides into three groups. Every seven gaussian beams are injected into one fixed focusing mirrors and all twenty-one beams reflected to one common steering mirror finally. The optical transmission characteristics and the convergence information of gaussian beams are checked and optimized. The EL or UL is installed on the equatorial or upper port with a port-plug modular structure.
In-situ real-time monitoring of spurious modes in HE11 transmission lines using multi-hole couplers in miter bends
Authors: Zach Alexander , Kasparek Walter , Lechte Carsten , Plaum Burkhard , Monaco Francesco , Schütz Harald , Stober Jörg , Idei Hiroshi , Hirth Thomas
Published: March 2019

Transmission of high-power millimeter waves for ECRH is often realised with oversized corrugated circular waveguides. Coupling from the gyrotron source to the waveguide is typically done via matching mirrors in free space. Small alignment errors of the system lead to the excitation of higher-order modes inside the waveguide beside the main transmission mode HE11. Those modes have comparably higher losses and can in worst case result in local fields exceeding the breakdown limit of the medium inside the waveguide.

For alignment control over the whole pulse duration of the gyrotron, a set of hole-array couplers placed into a miter bend mirror probes the field inside the waveguide. The arrays are designed to detect the marker modes for beam oﬀset and tilt (LP(e=o)11 )as well as for beam waist mismatch (LP02). In addition, a main mode coupler sensitive mostly for the HE11 content is used as a power monitor. By maximizing the signal of the power monitor and minimizing the content of marker modes, a first-order optimization of the coupling from free space to the waveguide can be achieved. Signal processing of the 140 GHz information is done at kHz range after downmixing, using a frequency shifted part of the power monitor signal.

As the measurement system is placed in a miter bend mirror, it can also be easily installed at various locations along the transmission line to check for possible misalignments of the waveguide connections between miter bends. Simulation and low power experimental results will be shown.
Schwarzkümmel: Medizin-Tipp aus der Bibel
Authors: Vlachojannis Julia , Chrubasik-Hausmann Sigrun
Published: March 2019

Seit dem Altertum wird der Schwarzkümmel, auch Gold der Pharaonen genannt, als Heilmittel geschätzt. Der Wirkstoff besitzt vorbeugende und heilende Wirkungen. Verschiedene experimentelle Untersuchungen untermauern die antientzündliche Wirkung. Der Antikrebswirkung liegt eine antiproliferative, proapoptotische, antioxidative, zytotoxische und antimetastatische Wirkung zugrunde. Außerdem stimuliert der Schwarzkümmel-Wirkstoff die Killerzellen im Blut. Wie synthetische Zytostatika wirkt die Leitsubstanz Thymochinon alkylierend. Tierexperimentell besaß der Schwarzkümmel in verschiedenen Modellen eine organprotektive Wirkung und reduzierte den durch Galaktose ausgelösten Alterungsprozess. Schwarzkümmelzubereitungen wirkten u. a. hypoglykämisch, blutdrucksenkend, antiasthmatisch, spasmolytisch, antidepressiv, antimikrobiell, antiviral und antiparasitär. Das präklinische Sicherheitsprofil ist inkomplett. Nach Zufuhr größerer Mengen ist mit toxischen Wirkungen zu rechnen.
Professionelle Pflege von suizidalen
Menschen
Authors: Höhne Lance
Published: March 2019

Wie können die beziehungsgestaltenden und interaktiven Elemente der
professionellen Pflege bei Suizidalität nach Bernd Kozel unter Berücksichtigung
des Primary-Nursing-Konzepts nach Marie Manthey umgesetzt werden? Dieses
umfangreiche und spannende Thema stellen wir Ihnen in dieser und der nächsten
Ausgabe vor. Im ersten Teil beleuchten wir das Konzept von Kozel und seine
Kernelemente.
Comparison of Game Movement Positional Profiles Between Professional Club and Senior International Rugby Union Players
Authors: Beard Adam , Chambers Ryan , Millet Gregoire P. , Brocherie Franck
Published: March 2019

The purpose of this study was to compare the game movement demands between professional club and senior international rugby union players. Data were obtained from 188 players from 4 professional club teams (Rabo Direct Pro12) and the affiliated international team during the 2014–15 season. Players were tracked by global positioning system (GPS) sampled at 10 Hz and were categorized into 6 different positional groups (front row forwards, FRF; second row forwards, SRF; back row forwards, BRF; half backs, HB; centres, C; outside backs, OB) and separated into playing standard (club vs. international level). Data on distance, distance per minute, high speed running, maximum velocity, sprint distance and efforts as well as repeated high-intensity locomotion efforts (RHILE) were collected. Significant effects (P<0 .05) between club and international were found for RHILE in all 6 positional groupings with a higher number of RHILE in international vs. club games. Significantly (P<0.05) greater total distance and meterage were also shown in international compared to club for OB position. The RHILE differences between club and international games whatever the positions appear of practical relevance for coaches and performance staff to concentrate on training protocols to enhance this quality as well as evaluation methods.
Stereoselective Aldol Additions of Glycolic Acid and Its Derivatives
Authors: Engesser Tobias , Brückner Reinhard
Published: March 2019

This review gives a comprehensive overview of aldol additions of glycolic acid derivatives to achiral aldehydes and acetals affording α,β-dihydroxycarboxylic acids or derivatives thereof. The focus is on simple diastereoselectivity. A selection of related aldol additions is also presented: aldol additions of glycolic acid derivatives to ketones with two different substituents and aldol additions of α-substituted glycolic acid derivatives.

1 Introduction

1.1 Organization of this Review

1.2 Outside the Scope of this Review: Aldol Additions Giving α,β-Dihydroxyaldehydes and α,β-Dihydroxyketones Diastereoselectively

1.3 Non-Aldol Routes to Diastereomerically Pure α,β-Dihydroxycarboxylic Acid Derivatives

2 Aldol Additions of Glycolic Acid (Derivative) Enolates to Aldehydes

2.1 Aldol Additions of Glycolate Enolates (‘Glycolic Acid Dianions’)

2.2 Aldol Additions of Glycolic Ester Enolates

2.3 Aldol Additions of Glycolic Thioester Enolates

2.4 Aldol Additions of Glycolimide Enolates

2.5 Aldol Additions of Glycolamide Enolates

2.6 Mukaiyama Aldol Additions of Silyl Ketene Acetals of Glycolic Esters­ and Thioesters

2.7 Aldol Additions of Glycoloyl Chlorides via Acyl Ammonium Enolates

3 Aldol-Providing Substitutions of Glycolimide Enolates in Acetals

4 Additions Related to Aldol Additions of Glycolic Acid Derivative Enolates to Aldehydes

4.1 Selected Simply Diastereoselective Aldol Additions of Enolates of Glycolic Acid Derivatives to Ketones with Two Different Substituents

4.2 Simply Diastereoselective Aldol Additions of Enolates of Glycolic Acid Derivatives with a Methyl Substituent at C-α (Lactic Acid Derivatives)

5 Conclusion
Recent Advances in Mainstream Hemostasis Diagnostics and Coagulation Testing
Authors: Favaloro Emmanuel , Lippi Giuseppe
Published: March 2019

The authors provide a narrative review of mainstream hemostasis analyzers. The review is presented in two parts. In the first part, the authors give voice to several internationally representative manufacturers of mainstream hemostasis analyzers. They ask these manufacturers to (1) answer a series of survey questions that may otherwise reflect common questions asked by users or potential users of their equipment, (2) provide a bullet list of their main focus areas, and (3) provide other information in regard to their instrumentation. The authors then offer their own personal perspective of the benefits of various aspects of such equipment, as well as a sampling of some hemostasis tests as currently available, or potentially in progress. It is hoped that this snapshot of mainstream hemostasis diagnostics and coagulation testing drives positive future changes that will ultimately provide the best outcomes for laboratories performing hemostasis assays and the patients they help diagnose and manage.
Resultados da orientação à prática de atividade física em crianças e adolescentes obesos
Authors: Valadão Rita , Miraglia Fernanda , Beghetto Mariur , Mello Elza
Published: March 2019

Introdução Diferentes métodos para tratar crianças e adolescentes com excesso de peso têm sido amplamente estudados, entre esses, a prática de atividade física. Um programa de atividade física que possa ser realizado no domicílio e aplicado no ambiente Sistema Único de Saúde (SUS), com esse intuito, ainda é inédito.

Objetivo Avaliar o nível de atividade física (AF) de crianças e adolescentes obesas, após orientação para executarem AF em casa e sua associação com escore-Z IMC (índice de massa corporal), escore-Z peso, percentuais de Massa Livre de Gordura (MLG), Massa Gorda (MG) e Taxa Metabólica Basal (TMB).

Método Foram acompanhados por um ano 15 meninas e 12 meninos com médias de idade de 11,29 ± 1,92 anos e percentil IMC P >98. O teste de impedância bioelétrica (BE) foi uitilizado para mensurar os percentuais de MLG, e MG e a TMB. O questionário International Physical Activity Questionnaire (IPAQ) foi utilizado para mensurar o nível de AF.

Resultados Verificou-se que crianças e adolescentes conseguem seguir uma rotina de AF em ambiente doméstico a partir de orientações mensais. Houve melhora de escore-z de peso em 59,3% dos pacientes, e do escore-z do IMC, em 77,8%, a TMB e a MLG aumentou em 96,3% da amostra, a MG diminuiu em 33,3% da amostra, durante o período de intervenção de 12 meses. Não se obteve êxito em diminuir as horas de sedentarismo para menos de duas por dia na maior parte da amostra.

Conclusão Crianças e adolescentes, se estimuladas, conseguem melhorar seus níveis de AF, passando de inativos para ativos, verificou-se ainda, a modificação de sua composição corporal neste período de 1 ano. A AF, mesmo que de forma isolada, colabora positivamente no manejo do excesso infanto-juvenil.
Sensibilidade não-celíaca ao glúten
Authors: Boarim Daniel
Published: March 2019

Entre as reações adversas a alimentos, os distúrbios relacionados ao glúten vêm atualmente ganhando cada vez mais espaço nas publicações científicas e não científicas. Estes distúrbios são divididos em três entidades: doença celíaca (DC), alergia ao trigo (AT) e sensibilidade não-celíaca ao glúten ou ao trigo (SNCG/T), considerando que este cereal vem sendo associado mais frequentemente às manifestações, discutindo-se ainda se não seria o real componente alimentar desencadeante. A DC é uma enteropatia autoimune, enquanto a AT é uma reação de hipersensibilidade, mediada ou não mediada pela imunoglobulina E (IgE). A SNCG/T é uma entidade emergente, de fisiopatologia ainda discutida, que vários pesquisadores propõem como diagnóstico de exclusão em relação à AT e à DC. A SNCG/T vem despertando grande celeuma popular e polêmica nos meios médicos. A presente revisão tem por objetivo abordar a SNCG/T, procurando elencar elementos de distinção dos outros dois distúrbios retrocitados discutindo aspectos como características clínicas, diagnóstico diferencial, fisiopatologia e tratamento. Em muitos trabalhos, salienta-se a possibilidade de sobreposição ou de confusão diagnóstica com outras doenças funcionais gastrointestinais, como síndrome do intestino irritável (SII) e oligossacarídeos, dissacarídeos, monossacarídeos e polióis fermentáveis (FODMAPs, na sigla em inglês). Concluímos que a SNGG/T, embora constitua uma entidade clínica reconhecida por um número expressivo de pesquisadores, ainda é objeto de amplo questionamento quanto à sua caracterização, ao seu diagnóstico e à sua fisiopatologia. Isto posto, considerando sua elevada prevalência estimada e as repercussões populares, indubitavelmente trata-se de assunto digno de estudos mais aprofundados e bem conduzidos.
Hepatocellular Carcinoma Risk Stratification by Genetic Profiling in Patients with Cirrhosis
Authors: Fujiwara Naoto , Hoshida Yujin
Published: March 2019

Prediction of future hepatocellular carcinoma (HCC) risk in the sizable chronic liver disease population is an urgent unmet need to enable regular HCC screening for early detection. Germline deoxyribonucleic acid polymorphisms likely represent etiology-specific host factors that determine HCC susceptibility, including single nucleotide polymorphisms in EGF, IFNL3, MICA, and TLL1 in hepatitis C with or without active viral infection, and PNPLA3, TM6SF2, and MBOAT7 in metabolic liver diseases. Transcriptome-based prognostic liver signature in diseased liver tissue has been associated with long-term HCC risk in viral and metabolic etiologies. Transcriptomic signatures of hepatic injury and specific cell type such as aggregated lymphocytes also predict HCC development. Circulating factors such as proteins and their chemical modification, nucleotides, and metabolites may serve for less-invasive assessment of short- or long-term HCC risk. These biomarkers will enable individual HCC risk-based personalized clinical management for cost-effective early HCC detection and improvement of patient survival.
On the behavior of the osmotic second virial coefficients of gases in aqueous solutions: Rigorous results, accurate approximations, and experimental evidence
Authors: Chialvo Ariel A. , Crisalle Oscar D.
Published: March 2019

We present a novel molecular-based approach for the determination of the osmotic second virial coefficients of gaseous solutes in dilute binary solutions, according to a recently proposed molecular thermodynamic formalism of gas solubility [A. A. Chialvo, J. Chem. Phys. 148, 174502 (2018) and Fluid Phase Equilib. 472, 94 (2018)]. We discuss relevant solvation fundamentals and derive new expressions including (i) the relations among infinite-dilution solvation quantities leading to a novel self-consistent route to the calculation of the osmotic second virial coefficients, (ii) the new microstructural interpretation of the resulting osmotic second virial coefficients based on Kirkwood-Buff integrals, the unambiguous discrimination between short- and long-range contributions, and their limiting behavior as the solvent approaches its critical conditions, (iii) new rigorous expressions for the calculation of the osmotic second virial coefficients using standard reference thermodynamic data, and (iv) their underlying interdependence based on the constrained state variable invoked in the density expansion. We then invoke the proposed formalism to shed some light on the inaccuracies behind current calculations of osmotic second virial coefficients from molecular theory and simulation as well as macroscopic correlations. To advance the microscopic understanding and illustrate the functional relationship between the osmotic second virial coefficients, Henry’s law constant, and the solute-solvent intermolecular asymmetry as a source of solution non-ideality, we use data for the microstructural and thermodynamic behavior of infinitely dilute Lennard-Jones systems obtained self-consistently via integral equations calculations. The newly derived relationships leading to the proposed formalism offer novel routes for the accurate determination of osmotic second virial coefficients of any type of solutes in dilute solutions regardless of the type and nature of the intermolecular interactions. However, for illustration purposes in the current work, we dealt with aqueous solutions of simple gases to exploit the abundance of standard thermodynamic data for the orthobaric Henry’s law constant and solute distribution coefficients, as well as the availability of results from molecular-based calculations and macroscopic correlations.
A Lagrangian fibration of the isotropic 3-dimensional harmonic oscillator with monodromy
Authors: Chiscop Irina , Dullin Holger R. , Efstathiou Konstantinos , Waalkens Holger
Published: March 2019

The isotropic harmonic oscillator in dimension 3 separates in several different coordinate systems. Separating in a particular coordinate system defines a system of three Poisson commuting integrals and, correspondingly, three commuting operators, one of which is the Hamiltonian. We show that the Lagrangian fibration defined by the Hamiltonian, the z component of the angular momentum, and a quartic integral obtained from separation in prolate spheroidal coordinates has a non-degenerate focus-focus point, and hence, non-trivial Hamiltonian monodromy for sufficiently large energies. The joint spectrum defined by the corresponding commuting quantum operators has non-trivial quantum monodromy implying that one cannot globally assign quantum numbers to the joint spectrum.
A new equation of state for homo-polymers in dissipative particle
dynamics
Authors: Minkara Mona S. , Noether Celeste O. , Jamadagni Sumanth N. , Ghobadi Ahmad F. , Eike David M. , Siepmann J. Ilja
Published: March 2019

A chain-revised Groot-Warren equation of state (crGW-EOS) was developed and tested to describe systems of homo-oligomeric chains in the framework of dissipative particle dynamics (DPD). First, thermodynamic perturbation theory is applied to introduce correction terms that account for the reduction in pressure with an increasing number of bonds at constant bead number density. Then, this EOS is modified by introducing a set of switching functions that yields an accurate second virial coefficient in the low-density limit. The crGW-EOS offers several improvements over the revised Groot-Warren equation of state and Groot-Warren equation of state for chain molecules. We tested the crGW-EOS by using it to predict the pressure of oligomeric systems and the B2 virial coefficient of chain DPD particles for a range of bond lengths. Additionally, a method is developed for determining the strength of cross-interaction parameters between chains of different compositions and sizes and for thermal and athermal mixtures. We explored how different levels of coarse-graining affect the upper-critical solution temperature.
Determination of bimolecular recombination constants in organic double-injection devices using impedance spectroscopy
Authors: Takada Makoto , Mayumi Takahiro , Nagase Takashi , Kobayashi Takashi , Naito Hiroyoshi
Published: March 2019

A method for determination of the bimolecular recombination constant in working double-injection diodes such as organic light-emitting diodes (OLEDs) and organic photovoltaics (OPVs) using impedance spectroscopy is proposed. The proposed method is based on the theory that was developed to interpret the negative capacitance that has previously been observed in both OLEDs and OPVs. The determination of the bimolecular recombination constants is demonstrated using working polymer light-emitting diodes based on poly(9,9-dioctylfluorene-alt-benzothiadiazole). These impedance spectroscopy measurements thus allow us to determine the required bimolecular recombination coefficients along with the electron and hole drift mobilities in working organic double-injection diodes.
Modeling quasi-3D needle-punched C/C composites using a linear simplification representative volume element model
Authors: Zhang Jianwei , An Peizhao
Published: March 2019

In this paper, a linear simplification model is proposed for predicting the flexibility of quasi-3D needle-punched C/C composites. The proposed model is based on the representative volume element, which we determined via three steps consisting of two modules: (1) a unidirectional fiber composite layer, which was composed of a homogenous matrix with random porosity throughout the material and randomly distributed short-cut fiber felt; (2) a needle-punched fiber composite layer, which possessed a random porous nature and a uniform distribution of needle-punched fibers in the matrix. We then utilized the analytical homogenization model, the Halpin–Tsai formula, and the Gox formula to predict the elasticity of the composites. The predicted elasticity properties were compared to experimental data reported in the literature to evaluate the reliability and precision of the proposed linear simplification model. The predictions were in good agreement with the experimental data. Furthermore, a series of parametric numerical calculations were performed to examine the effects of the micro-factor and integral thickness factors on the elastic properties of the composites.
On using Rayleigh scattering for in situ spectral calibration of Thomson scattering diagnostics
Authors: Bozhenkov S. A. , Heym S. J. , Beurskens M. N. A. , Fuchert G. , Pasch E. , Scott E. R. , Wolf R. C.
Published: March 2019

A new method for in situ spectral calibration of Thomson scattering diagnostics is proposed. The idea of the method is to apply a wavelength tunable optical parametric oscillator for measurements of Rayleigh scattering at different wavelengths, from which relative sensitivities can be calculated. This extends the usual approach where Rayleigh scattering is used only at a single wavelength for the absolute calibration and spectral sensitivities are obtained separately. With the new approach, the full diagnostic setup is spectrally calibrated at once. Such a calibration can be repeated at regular intervals during an experimental campaign since it does not require a break of the vacuum. In this paper, the Rayleigh scattering calibration is tested in a laboratory setup with a sample Wendelstein 7-X (W7-X) polychromator. It is shown that relative sensitivities of spectral channels can be recovered with a sufficient resolution even under conditions of significant stray light. The stray light is overcome by measuring the linear dependence of the scattered signal on the gas pressure. Good results of laboratory tests motivate the installation of the new calibration system for the Thomson scattering diagnostic at W7-X.
Structural and electronic properties of the spin-filter material CrVTiAl with disorder
Authors: Stephen Gregory M. , Buda Gianina , Jamer Michelle E. , Lane Christopher , Kaprzyk Stanislaw , Barbiellini Bernardo , Graf David , Lewis Laura H. , Bansil Arun , Heiman Don
Published: March 2019

The effects of chemical disorder on the electronic properties of the spin-filter material CrVTiAl are investigated experimentally and theoretically. Synchrotron X-ray diffraction experiments on bulk CrVTiAl and the associated Rietveld analysis indicate that the crystal structure consists primarily of a mixture of a partially ordered B2 phase, a fully disordered A2 phase, and a small component of an ordered L21 or Y phase. High temperature resistivity measurements confirm the existence of a bandgap. First-principles, all-electron, self-consistent electronic structure computations show that the chemically disordered A2 and B2 phases are metallic, while the spin-filter properties of the ideal Y-type phase are preserved in the presence of L21 disorder (Cr and V mixing). The Hall coefficient is found to decrease with increasing temperature, similar to the measured increase in the conductivity, indicating the presence of thermally activated semiconductor-like carriers.
Structure of water confined between two parallel graphene plates
Authors: Cai Xiaoxia , Xie Wen Jun , Yang Ying , Long Zhuoran , Zhang Jun , Qiao Zhuoran , Yang Lijiang , Gao Yi Qin
Published: March 2019

We study, in this paper, the physical properties of water confined between two parallel graphene plates with different slit widths to understand the effects of confinement on the water structure and how bulk properties are reached as the water layer thickens. It was found that the microscopic structures of the interfacial liquid layer close to graphene vary with the slit width. Water tends to locate at the center of the six-membered ring of graphene planes to form triangular patterns, as found by others. The narrower the slit width is, the more pronounced this pattern is, except for the slit width of 9.5 Å, for which a well-defined two-layer structure of water forms. On the other hand, squared structures can be clearly seen in single snapshots at small (6.5 Å and 7.5 Å) but not large slit widths. Even at small slit widths, the square-like geometry is observed only when an average is taken for a short trajectory, and averaging over a long time yields a triangular pattern dictated by the graphene geometry. We estimate the length of time needed to observe two patterns, respectively. We also used the two-phase thermodynamic model to study the variation of entropy of confined water and found that at 8.5 Å, the entropy of confined water is larger than that of bulk water. The rotational entropy of confined water is higher than that of bulk water for all slit widths due to the reduction of the hydrogen bond in the confined space.
Time of arrival and localization of relativistic particles
Authors: Anastopoulos Charis , Savvidou Ntina
Published: March 2019

Constructing observables that describe the localization of relativistic particles is an important foundational problem in relativistic quantum field theory (QFT). The description of localization in terms of single-time observables leads to conflict with the requirement of causality. In this paper, we describe particle localization in terms of time-of-arrival observables, defined in terms of the interaction between a quantum field and a measuring apparatus. The resulting probabilities are linear functionals of QFT correlation functions. Specializing to the case of a scalar field, we identify several time-of-arrival observables differing on the way that the apparatus localizes particle-detection records. Maximum localization is obtained for a unique observable that is related to the Newton-Wigner position operator. Finally, we define a measure of localizability for relativistic particles in terms of a novel time-energy uncertainty relation for the variance of the time of arrival.
TAPS: A traveling-salesman based automated path searching method for functional conformational changes of biological macromolecules
Authors: Zhu Lizhe , Sheong Fu Kit , Cao Siqin , Liu Song , Unarta Ilona C. , Huang Xuhui
Published: March 2019

Locating the minimum free energy paths (MFEPs) between two conformational states is among the most important tasks of biomolecular simulations. For example, knowledge of the MFEP is critical for focusing the effort of unbiased simulations that are used for the construction of Markov state models to the biologically relevant regions of the system. Typically, existing path searching methods perform local sampling around the path nodes in a pre-selected collective variable (CV) space to allow a gradual downhill evolution of the path toward the MFEP. Despite the wide application of such a strategy, the gradual path evolution and the non-trivial a priori choice of CVs are also limiting its overall efficiency and automation. Here we demonstrate that non-local perpendicular sampling can be pursued to accelerate the search, provided that all nodes are reordered thereafter via a traveling-salesman scheme. Moreover, path-CVs can be computed on-the-fly and used as a coordinate system, minimizing the necessary prior knowledge about the system. Our traveling-salesman based automated path searching method achieves a 5-8 times speedup over the string method with swarms-of-trajectories for two peptide systems in vacuum and solution, making it a promising method for obtaining initial pathways when investigating functional conformational changes between a pair of structures.
Temperature dependent optical and dielectric properties of liquid water studied by terahertz time-domain spectroscopy
Authors: Zhou Jun , Rao Xin , Liu Xiaoming , Li Tao , Zhou Lin , Zheng Yanshun , Zhu Zheng
Published: March 2019

Terahertz waves have found wide applications in the biological and medical areas. Since water is one of the most important ingredients in the biological systems, it is necessary to investigate its optical and dielectric properties in the terahertz range. These fundamental physical parameters play an important role in many applications, such as biological imaging and hyperthermia applications, and are temperature dependent. In order to shed more light on the property of temperature dependence, we performed a systematic investigation by changing the temperature of the water sample and using a terahertz time-domain spectrometer. The experimental results show that when the temperature increases from 275 K to 340 K, the refractive index and the complex dielectric constant of water increase noticeable, with the absorption coefficient increased observably. A good agreement is found between experimental data and the double Debye model.
Vorticity dynamics of the three-dimensional Taylor-Green vortex problem
Authors: Sharma Nidhi , Sengupta Tapan K.
Published: March 2019

The three-dimensional (3D) Taylor-Green Vortex (TGV) flow problem has been used to study turbulence from genesis to eventual decay governed by the 3D Navier-Stokes equation. The evolution of the TGV shows that the solution becomes unstable at very early times and eventually becomes turbulent, but a study of this transition has not been advanced so far. The computations are performed using a high accuracy compact scheme on a uniform grid, with the fourth-order Runge-Kutta time integration method. The vector potential-vorticity (Ψ→,ω→)-formulation of the governing equations is solved in a cubic periodic domain with one complete basic unit of a TGV cell in the interior of the domain at t = 0. The TGV problem allows one to study the vorticity dynamics using highly accurate formulation because of periodic boundary conditions. Simulations performed for different Reynolds numbers and grid resolutions reveal that numerical error in computations induce a period-doubling bifurcation, which leads to new spatial symmetries maintained up to intermediate times, followed by simultaneous stretching and fragmentation of vortices resulting in a decaying turbulent flow. The compensated energy spectrum of the 3D TGV flow displays inertial subrange at t = 9, after which the generated turbulence starts decaying. The power law for turbulent kinetic energy decay is analyzed, and the decay exponent is noted to approach unity as time increases.
Correlation between bias-dependent ESR signals and magnetic field effects in organic light emitting diodes
Authors: Kanemoto Katsuichi , Hatanaka Shuto , Suzuki Takayuki
Published: March 2019

The bias dependent behaviors in magnetic field effects (MFEs) of the current and the electroluminescence (EL) intensity in organic light emitting diodes (OLEDs) have been investigated from electrically-detected and EL-detected magnetic resonance (EDMR and ELDMR) techniques. An EDMR signal was not detected from the electron-only device, and the hole-only device gave only a much smaller EDMR signal than the OLED device. Both the EDMR and ELDMR signals observed from the OLED are concluded to primarily arise from the spin-dependent reaction of electron-hole (e-h) pairs. Both the normalized EDMR and ELDMR signal intensities decrease by increasing the operation bias of OLED, because the increased bias enhances the dissociation and recombination of e-h pairs beyond the increase in the pair-density by the bias. The bias-dependence curves of magneto-conductances and magneto-EL intensities are demonstrated to be very similar to those of the normalized EDMR and ELDMR, respectively. This similarity gives direct evidence that e-h pairs determine the MFEs of the present OLEDs at room temperature and that the MFEs are reduced by bias-dependent dissociation and recombination of e-h pairs. The bias-dependent EDMR and ELDMR experiments are thus effective as probing methods to examine the magnetic field properties via e-h pairs of OLEDs.
Recovery of metastable dense Bi synthesized by shock compression
Authors: Gorman M. G. , Coleman A. L. , Briggs R. , McWilliams R. S. , Hermann A. , McGonegle D. , Bolme C. A. , Gleason A. E. , Galtier E. , Lee H. J. , Granados E. , McBride E. E. , Rothman S. , Fratanduono D. E. , Smith R. F. , Collins G. W. , Eggert J. H. , Wark J. S. , McMahon M. I.
Published: March 2019

X-ray free electron laser (XFEL) sources have revolutionized our capability to study ultrafast material behavior. Using an XFEL, we revisit the structural dynamics of shock compressed bismuth, resolving the transition sequence on shock release in unprecedented details. Unlike previous studies that found the phase-transition sequence on shock release to largely adhere to the equilibrium phase diagram (i.e., Bi-V → Bi-III → Bi-II → Bi-I), our results clearly reveal previously unseen, non-equilibrium behavior at these conditions. On pressure release from the Bi-V phase at 5 GPa, the Bi-III phase is not formed but rather a new metastable form of Bi. This new phase transforms into the Bi-II phase which in turn transforms into a phase of Bi which is not observed on compression. We determine this phase to be isostructural with β-Sn and recover it to ambient pressure where it exists for 20 ns before transforming back to the Bi-I phase. The structural relationship between the tetragonal β-Sn phase and the Bi-II phase (from which it forms) is discussed. Our results show the effect that rapid compression rates can have on the phase selection in a transforming material and show great promise for recovering high-pressure polymorphs with novel material properties in the future.
Quantized thermal conductance in metallic heterojunctions
Authors: Mosso Nico , Prasmusinto Alyssa , Gemma Andrea , Drechsler Ute , Novotny Lukas , Gotsmann Bernd
Published: March 2019

To develop next-generation electronics and high efficiency energy-harvesting devices, it is crucial to understand how charge and heat are transported at the nanoscale. Metallic atomic-size contacts are ideal systems to probe the quantum limits of transport. The thermal conductance and electrical conductance of gold atomic contacts have been recently proven to be quantized at room temperature. However, a big experimental challenge in such measurements is represented by the fast breaking dynamics of metallic junctions at room temperature, which can exceed the typical response time of the thermal measurement. Here, we use a break-junction setup that combines Scanning Tunneling Microscopy with suspended microelectro-mechanical systems with a gold-covered membrane and an integrated heater acting also as a thermometer. By using other metals as tip materials, namely, Pt, PtIr, and W, we show heat transport measurements through single gold atomic contacts. The dependence of the thermal conductance is analysed as a function of contact size and materials used. We find that by using Pt and Pt-Ir tips, we can maximize the mechanical stability and probability of forming single Au atomic contacts. We then show the quantization of the electrical and thermal conductance with the verification of the Wiedemann-Franz law at the atomic scale. We expect these findings to increase the flexibility of experimental techniques probing heat transport in metallic quantum point contacts and to enable the investigation of thermal properties of molecular junctions.