bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution mechanism of conflict between pedestrian and vehicle based on evolutionary game theory
Authors: Wei Li-Ying  , Cui Yu-Feng  , Li Dong-Ying  ,   School of Traffic and Transportation, Beijing Jiaotong University, Beijing 100044, China
Published: December 2020

When pedestrian and vehicle are in conflict, they will pass at a certain probability after they have made a simple judgment respectively. According to the actual situation of the conflict between pedestrian and vehicle, the concept of basic payoff, conflict loss, waiting loss and mutual avoiding loss are put forward. A game matrix of the conflict between pedestrian and vehicle is consequently established. Then the evolutionary analysis paradigm is introduced, and the dynamic model of the conflict evolution between pedestrian and vehicle is established. After that, the position and stability of the equilibrium point and the evolution mechanism of the system in different traffic situations are analyzed in detail. It is found that the relative size between conflict loss and waiting loss of pedestrian and vehicle are different, corresponding to different evolution directions of the system. The possible evolutionary directions include “vehicles first”, “pedestrians first”, “neither vehicles nor pedestrians goes first”, “vehicles and pedestrians do not yield to each other”. In addition, in this paper, we define the traffic concept of opportunity loss, and analyze the sensitivity of the system to the mutual avoiding loss and the opportunity loss of pedestrian and vehicle. It is found that the increasing of the mutually avoiding loss of pedestrian or vehicle has a positive effect on improving the probability of each passing conflict zone, but it has a negative effect on reducing the probability of each passing conflict zone. On the other hand, the effect of opportunity loss is just the opposite to the mutual avoiding loss. The dynamic model established in this paper can provide a theoretical basis for the macro control of the conflict evolution direction between pedestrian and vehicle. For instance, the current conflict situation between pedestrian and vehicle in a city is “vehicles first”. For promoting the traffic civilization, the transportation officials hope to change the current conflict situation to realize the “pedestrians first”. According to the model established in this paper, some parameters of the game matrix on the conflict between pedestrian and vehicle can be changed by formulating relevant highway traffic regulations to adjust the evolution direction of the conflict between pedestrian and vehicle.
Atomic fountain frequency standard: principle and development
Authors: Wang Qian  , Wei Rong  , Wang Yu-Zhu  ,   Key Laboratory for Quantum Optics, Shanghai Institute of Optics and Fine Mechanics, the Chinese Academy of Sciences, Shanghai 201800, China;,   University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

The principle and development of fountain frequency standard are introduced in this paper. Fountain frequency standard is an atomic clock technology developed in recent 20 years. It is based on laser cooling technology, and realizes the trapping and projection of the cold atom medium with laser cooling technology. In the process of launching upward and falling back, the cold atom medium first completes the preparation of atomic state, then passes through the microwave cavity twice to achieve the Ramsey interaction; between the two interactions it undergoes free evolution, and finally the Ramsey interference fringes are obtained by detecting the atomic interference probability with the two-level fluorescence detection method in the detection region, and the frequency is locked with a line width of the central fringe being about 1 Hz. The stability and uncertainty of the frequency are two important indexes of the fountain frequency standard. The factors influencing the stability of the fountain clock frequency mainly are quantum projection noise and electronic noise. At present, the short term stability of the fountain clock is (10-13-10-14)τ-1/2, and the long term stability is (10-16-10-17). The frequency uncertainty of the fountain frequency standard is mainly influenced by the two-order Zeeman frequency shift, the blackbody radiation frequency shift, the cold atom collisional frequency shift, and the frequency shift relating to the microwave. The uncertainty of the fountain clock is around 10-16 currently. As a reference frequency standard, the working media of the fountain clock mainly are 133Cs and 87Rb. All international metrology institutions have been developing the fountain frequency standard, and it plays a more and more important role in establishing the coordinated universal time and the calibration of the international atomic time. In addition, the fountain frequency standards are also used to study high-precision time-frequency reference and time comparison chain, and verify basic physical theories.
A method of characterizing axial stress in ferromagnetic members using superficial magnetic flux density obtained from static magnetization by permanent magnet
Authors: Deng Dong-Ge  , Zuo Su  , Wu Xin-Jun  ,   School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China;,   Institute of Systems Engineering, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

It is of great significance to obtain the information about the stress of load-bearing ferromagnetic members quickly in order to maintain the safety of the infrastructure. The key point is to accurately and quickly determine the characterization parameters which change sensitively and linearly with the stress. Among the existing electromagnetic methods of determining axial stress in ferromagnetic members, exciting coils are usually adopted to exert a time-varying magnetic field on the ferromagnetic members, which will induce the problems of winding coils, coil heating, and eddy current that influences the test results. What is worse is that it is inevitable to compare the experimental data point by point to determine the adequate magnetic parameter characterizing the stress, which influences the fast determining of the axial stress in ferromagnetic members. In order to break through these limitations, in this paper we propose a method of determining the axial stress in ferromagnetic members by using superficial magnetic flux density obtained from static magnetization in permanent magnets. In this method, permanent magnetizers are adopted to excite the overall damping and local uniform spatially-varying constant magnetic field on ferromagnetic members. A testing probe including Hall chip array is adopted to measure the superficial axial and radial magnetic flux density to determine the axial stress of the ferromagnetic member. The principle is elaborated to choose the adequate superficial magnetic flux density fast and precisely for characterizing the axial stress in ferromagnetic members. According to the theory of demagnetizing field, the continuity of the tangential magnetic field strength and Gauss's law for magnetism, the relational equation between the derivative of superficial axial magnetic flux density with the stress and the derivative of superficial radial magnetic flux density with the stress is established. Then, an experiment is conducted to verify the proposed method. The experimental results show that according to this relational equation, the superficial magnetic flux density with the highest stress sensitivity can be determined quickly and accurately. What is more, the linearity of the superficial magnetic flux density varying with the stress is good, and the goodness of the corresponding linear fitting R2 is greater than 0.98. It means that the determined superficial magnetic flux density can be used as a feature parameter to characterize the stress in ferromagnetic members. The proposed method of determining the axial stress in this paper can provide a new way of on-line detecting the working stress in ferromagnetic components.
Research and development of continous wave 100 kW absorption harmonicfilter in X-band
Authors: Liu Hai-Xu  , Hou Man-Hong  , Li Xin-Sheng  ,   The 27 th Institute of CETC, Zhengzhou 450047, China
Published: December 2020

A gradient leaky-wall waveguide loaded absorbing load filter structure is proposed, which is designed for harmonic suppression in super-high power transmitter of deep-space probe. The attenuation loss characteristics of the filter is analyzed according to the equivalent circuit method, and the massive structure is simulated by the electromagnetic field simulation software. The filter sample which includes one main waveguide, 288 deputy waveguides and 288 absorb loads is processed following the simulating and designing sizes. In order to prevent microwave from leaking and keep good air tightness under the condition of high power, all the components of the filter will be welded together by means of vacuum welding, and then the sample is cleaned ultrasonically. Finally, the filter sample is tested under small signal and large signal separately. According to our test results, the pass band max insertion loss of the filter is 0.3 dB, the min suppression of second harmonic is 75 dB, the min suppression of third harmonic is 50 dB, and the min suppression of fourth harmonic is 35 dB. The measured results show that they are almost the same as the simulation results, and consistent completely with the anticipated. We further conduct the high power experiment on the filter under a large signal of 100 kW, showing that the continuous wave power capacity of the filter can reach up to 100 kW through the power resistance test with the liquid-cooled system. All the test data show that the study and development are very successful. At present, the filer has been applied to a type of ground high power transmitter, and its performances and indicators behave well.
Influence of multipactor discharge on field-buildup process in radio-frequency plate cavity
Authors: Dong Ye  , Liu Qing-Xiang  , Pang Jian  , Zhou Hai-Jing  , Dong Zhi-Wei  ,   School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, China;,   Institute of Applied Physics and Computational Mathematics, Beijing 100094, China;,   Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

In this paper, the hybrid physical model is established based on the equivalent circuit for describing dynamic radio-frequency (RF) field buildup and the particle-in-cell (PIC) method for describing two-sided multipactor discharge in plate cavity. By using our built 1D3V-PIC code for multipactor discharge and fully equivalent circuit code for RF field buildup, the influence of multipactor discharge on the dynamic process of RF field buildup is numerically investigated and analyzed in detail under the condition of cavity with different Q-values. The numerical results could be concluded as follows. Under the condition of no multipactor discharge in dynamic process of RF field buildup, the higher the Q-value, the longer the buildup-time is. The input energy is equal to the sum of stored energy and consumed energy in cavity, the speed of energy storing is higher than the speed of energy consuming at the beginning stage of RF field buildup and then the speed of energy storing becomes lower than the speed of energy consuming. When the process of RF field buildup is finished, the average power of input is equal to the average power of consumed power in cavity. Under the condition of multipactor discharge loading in dynamic process of RF field buildup, the higher the Q-value, the later the start-time is and the longer the interaction time-interval of multipactor discharge is. The bigger the area of secondary electron emission, the higher the peak-value of secondary electron current is. The failure of RF field-buildup is caused by the continuous loading of multipactor discharge. The higher the Q-value or the bigger the area of secondary electron emission, the lower the probability of RF field buildup success is. The simulated results could partly provide a reference for engineering design.
Physical model of conductive dislocations in GaN Schottky diodes
Authors: Wang Xiang  , Chen Lei-Lei  , Cao Yan-Rong  , Yang Qun-Si  , Zhu Pei-Min  , Yang Guo-Feng  , Wang Fu-Xue  , Yan Da-Wei  , Gu Xiao-Feng  ,   Engineering Research Center of Internet of Things Technology Applications(Ministry of Education), Department of Electronic Engineering, Jiangnan University, Wuxi 214122, China;,   State Key Discipline Laboratory of Wide Band-gap Semiconductor Techonology, Xidian University, Xi'an 710071, China
Published: December 2020

The excessive leakage current, commonly observed in GaN Schottky barrier diodes (SBDs), severely degrades device electrical performance and long-term reliability. This leakage current relates to the dislocation-related conductive states as observed by microscopy. Up to now, various transport models have been proposed to explain the leakage current, but none of them can clearly describe in physics the electrically active dislocations. One just equivalently regarded the electric defect as a continuum conductive defect state within the forbidden band, without considering the microscopic electrical properties of the dislocations. Here in this work, on the basis of numerical simulation, we propose a phenomenological model for the electrically active dislocations to explain the leakage conduction of the GaN Schottky diodes, which are fabricated on a freestanding bulk substrate n-GaN wafer with a low dislocation density of about 1.3106 cm-2. In this model, we emphasize that the acceptor-like traps at the core of dislocations could capture electrons from the nearby donor-like traps, resulting in a high Coulomb potential and a decreasing potential at the donor-like sites. In this case, the core of dislocations would be negatively charged, and not favor the electron transport due to a strong Coulomb scattering effect, while the shallow donor-like traps around them can lead to a significant tunneling leakage component. This model is consistent well with the common observation of the localized currents at the edges of the surface V-defects in GaN. The shallow donor-like defects in GaN induced by the substitution of oxygen for nitrogen (ON), rather than the nitrogen vacancies, act as the dominant donor impurities responsible for the significant leakage current, which has a density on the order of 1018 cm-3 and an activation energy of about 47.5 meV, because 1) it has been demonstrated that during the material growth, oxygen diffusion toward the surface pits of dislocations via nitrogen vacancies could produce an exponentially decayed distribution with a density of at least 1017 cm-3, in good agreement with our derivation; 2) by the first principle calculation, the thermal activation energy of the oxygen-related donors is determined to be about 50 meV, which is very close to our derived 47.5 meV. According to this model, we propose that reducing the ON defect density during device growth is a feasible method to suppress the high leakage current in GaN-based SBDs. In addition, this study can also improve our understanding of the leakage current in other GaN-based devices.
Ab initio calculation of the thermal neutron scattering cross sections of uranium mononitride
Authors: Wang Li-Peng  , Jiang Xin-Biao  , Wu Hong-Chun  , Fan Hui-Qing  ,   1. School of Nuclear Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China;,   2. Northwest Institute of Nuclear Technology, Xi'an 710024, China;,   3. School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China
Published: December 2020

Nuclear design and neutronic analysis of thermal neutron reactor need high reliable thermal neutron cross sections. Uranium mononitride (UN) is a candidate fuel material for advanced power reactor with its better thermodynamics and accident tolerance. However, in thermal neutron region, reliable thermal neutron scattering cross sections are lacked for UN, which is disadvantageous to reactor physics simulations. The scattering law of the UN fuel material may impact the thermal neutron spectrum and criticality of the reactor systems. Neutron cross sections in thermal range are correlated with energy, temperature, physical and chemical properties of the scattering medium, reflecting the phonon spectra of material itself. In this paper, based on the ab initio method of quantum mechanics, phonon density of states in UN are calculated by VASP/PHONON code, and used for integral to obtain UN heat capacity at a constant volume. Adopting this new phonon density of states, NJOY/LEAPR code is used to generate S (, ) data by thermal neutron scattering theory and NJOY/THERMR utilizes these data to produce thermal scattering matrix in order to investigate thermal kernel effect of UN. Subsequently, thermal neutron scattering cross sections of UN are generated with NJOY code system. Comparison with uranium dioxide (UO2) in the traditional PWR is done. Results indicate that optimized lattice parameter are in good agreement with the database; the optical modes are well separated from the acoustic modes compared with UO2; heat capacity at a constant volume is consistent with experimental value; the inelastic and elastic cross sections of 238U in UN are lower than those of 238U in UO2. N in UN only deals with incoherent part in elastic cross sections. As the temperature increases, elastic cross sections of UN decrease while inelastic ones increase, and cross sections approach to free atom cross section at high energies. Considering the limitations of 14N, the scattering law and inelastic scattering cross sections are also under investigation using 15N in UN compound. This paper's conclusion fulfill the vacancy of thermal neutron scattering cross sections of UN, which laid a foundation for systematic study on the neutronics properties of UN fuel in the light water reactors as well as for the design of new neutron moderators and neutron filer.
Renormalization of photon dyadic Green function by finite element method and its applications in the study of spontaneous emission rate and energy level shift
Authors: Zhao Yun-Jin  , Tian Meng  , Huang Yong-Gang  , Wang Xiao-Yun  , Yang Hong  , Mi Xian-Wu  ,   College of Physics, Mechanical and Electrical Engineering, Jishou University, Jishou 416000, China;,   College of Electrical and Information Engineering, Huaihua University, Huaihua 418000, China
Published: December 2020

The spontaneous emission rate and the energy level shift of a quantum dot in any micro-nanostructures can be expressed by the classical dyadic Green's function. However, the real part of the dyadic Green's function is divergent, when the source point and the field point are at the same position. This leads to an unphysical divergent level shift. Theoretically, the dyadic Green's function can be decomposed into a homogeneous part and a scattering part. Traditionally, the homogeneous field contribution is introduced into the definition of the transition frequency and the only need is to consider the effect of the scattering part which is non-divergent. Another renormalization method is to average the Green tensor over the volume of the quantum dot. In this work, a finite element method is proposed to address this problem. The renormalized dyadic Green function is expressed by the averaged radiation field of a point dipole source over the quantum dot volume. For the vacuum case, numerical results of the renormalized Green tensor agree well with the analytical ones. For the nanosphere model, the renormalized scattering Green tensor, which is the difference between the renormalized Green tensor and the analytical renormalized one in homogeneous space, agrees well with the analytical scattering Green tensor in the center of the quantum dot. Both of the above models clearly demonstrate the validity and accuracy of our method. Compared with the previous scattering Green function method where two different finite element runs are needed for one frequency point, our renormalization method just needs one single run. This greatly reduces the computation burden. Applying the theory to a gap plasmonic nano-cavity, we find extremely large modifications for the spontaneous emission rate and the energy level shift which are independent of the size of the quantum dot. For frequency around the higher order mode of the nano-cavity, spontaneous emission enhancement is about Г/Г0 2.02106 and the energy level shift is about △ 1000 meV for a dipole moment 24D. These findings are instructive in the fields of quantum light-matter interactions.
Recent progress of nonvolatile, multifunctional and programmable spin logic
Authors: Han Xiu-Feng  , Wan Cai-Hua  ,   Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;,   School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

Spin logic has advantages of nonvolatility, CMOS compatibility and fast speed, thus it has become a promising alternative solution to realizing non von Neumann computing architectures. Here in this paper we show two hopeful spin logic solutions based on spin Hall effect and spin orbit torques. First basic Boolean logic and storage functions are realized in a spin Hall logic device. Furthermore, utilizing symmetric requirements for magnetic fields and applied current, programmability of the spin logic device among 5 different Boolean logic functions, AND, OR, NOT, NOR and NAND, is even realized. The demonstration of programmable spin Hall logic can advance the birth and development of practical spin logic devices and circuits.
Precision spectroscopy on the 2 3S-2 3P transition of atomic helium
Authors: Zheng Xin  , Sun Yu  , Chen Jiao-Jiao  , Hu Shui-Ming  ,   Hefei National Laboratory for Physical Science at the Microscale, University of Science and Technology of China, Hefei 230026, China;,   CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei 230026, China
Published: December 2020

Precision measurement in few-electron atomic systems played an important role in testing fundamental physics and determination of the fundamental physical constants throughout the past few decades.Atomic helium,as the simplest multi-electron system,its energy levels can be calculated with a very high precision by means of ab-initio calculations, and can be accurately determined using precision spectroscopy.Test of quantum theories can be achieved by comparing theoretical predictions with experimental results.In case of any disagreement,it might imply that there are some undiscovered systematic effects,or might signal physics beyond the standard model.Particularly,the 2 3PJ energy level in atomic helium is considered as one of the best atomic systems for determining the fine-structure constant α.High precision helium spectroscopy can also be used for setting constraints on exotic spin-dependent interactions,and may provide an accurate determination of the helium nuclear charge radius.Comparison of results from electronic and muonic helium may provide a sensitive test of universality in electromagnetic interactions of leptons,and may help solve the socalled “proton size puzzle”.In this paper,we summarize our recent progress on precision spectroscopy of atomic helium. By using transverse cooling and deflection,we are able to prepare a low-noise bright source of atoms in the metastable state 2 3S1.The initial state preparation is completed by optical pumping,followed by laser spectroscopy in the 2 3S-2 3P transition.The 2 3P0-2 3P2 and 2 3P1-2 3P2 fine-structure intervals are determined to be (31908130.98 ±0.13) kHz and (2291177.56 ±0.19) kHz,respectively.Compared with calculations including terms up to α7m,the deviation for the α-sensitive interval 2 3P0-2 3P2 is only 0.22 kHz,which paths way for further improvement of theoretical predictions and independent determination of α with a 2-ppb precision.The 2 3S-2 3P transition frequency is determined with an accuracy of 1.4 kHz by utilizing comb-linked spectroscopy and first-order Doppler cancellation technique.Our result is not only more accurate but also differs by as much as 50 kHz (20 σ) from the previously reported result.This discrepancy remains unsolved and indicates the need for further independent measurements.In combination with ongoing theoretical calculations,this new result may provide the most accurate determination of helium nuclear charge radius.Prospects for future improvements in relevant precision measurements,including simple molecules,are also discussed.
Monte Carlo method for computing relativistic photon-Maxwellian electron scattering cross sections
Authors: Li Shu  ,   Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
Published: December 2020

Compton and inverse Compton scattering from relativistic Maxwellian electrons both have an important feature, i.e. calculating the radiation transport in high-temperature and full-ionized plasma. Description and evaluation of relativistic photon-Maxwellian electron scattering are numerically complex and computationally time consuming. A Monte Carlo method is proposed to simulate photon scattering with relativistic Maxwellian electron and compute the scattering cross-sections. To compute the total cross-section of a photon of energy hν interacting with electrons at temperature Te in the laboratory coordinate, the calculation steps of Monte Carlo scheme are described as follows. The first step is to sample the velocity of an electron, the directions are isotropically sampled, and the speed is sampled from the relativistic Maxwellian distribution at temperature Te. The second step is to transform the photon energy hν into the photon energy in the coordinate in which the electron is at rest. The third step is to use the exact Klein-Nishina formula to compute the cross-sections. The fourth step is go back to the first step, and cycle this many times. The last step is to summarize all computed cross-sections and averaged them, and the average value is what we need. The operation and corresponding formula for each step are described in this paper. A better method of sampling the speed of a relativistic electron is expected to be found.A Monte Carlo processor is developed to compute the scattering cross-section of a photon of any energy, interacting with electrons at any temperature. To check this method, scatterings of the photons of various energies with electrons with various temperatures are simulated, and the results are compared with those from the numerical integration method. The comparison indicates that the simulated cross-sections are in pretty good agreement with those from the multiple integration method for the cases of electron temperature less than 25 keV. But unfortunately, the difference is obvious for the case of temperature more than 25 keV, and the error increases with temperature increasing. Why so? When the temperature is more than 25 keV, the sampling of electron speed is inaccurate when using the present method, which maybe results in this difference. So, we need to find a more accurate method of sampling relativistic electron speed to solve this problem in the future.
Effect of surface elasticity on drainage process of vertical liquid film with soluble surfactant
Authors: Ye Xue-Min  , Li Ming-Lan  , Zhang Xiang-Shan  , Li Chun-Xi  ,   Key Laboratory of Condition Monitoring and Control for Power Plant Equipment, North China Electric Power University, Baoding 071003, China
Published: December 2020

The aim of the present paper is to investigate the gravity-driven draining process containing soluble surfactant when considering the coupling effects of surface elasticity and surfactant solubility. A nonlinear coupling evolution equation including liquid film thickness, surface velocity and surfactant concentration (both on the surface and in the bulk) is established based on the lubrication theory. Assuming that the top of liquid film is attached to the wireframe and the bottom is connected to a reservoir, the drainage evolution is simulated with the software called FreeFem. The effects of surface elasticity and solubility on liquid film draining are discussed under their coupling. The simulation results show that the surface elasticity is an indispensable factor in the process of liquid film drainage with soluble surfactant, and the surfactant solubility also has an important influence on the process. At the initial stage of liquid draining, the initial thickness of liquid film increases with increasing surface elasticity, and the surface tends to be more rigid; with the drainage proceeding, the liquid film with high and low elasticity illustrate different notable draining features:in the case of low surface elasticity, the distribution of surfactant forms a surface tension gradient from top to bottom on the film surface, leading to positive Marangoni effect that counteracts gravity. However, in the case of high elasticity, the film surface presents a surface tension gradient from bottom to top, resulting in a reverse Marangoni effect, which accelerates the draining and makes the film more susceptible to instability. The solubility of surfactant dominates the number of adsorbent molecules on the film surface, which affects the surface elasticity. When the solubility of the surfactant is great (β → 0), the film is extremely unstable, and it breaks down quickly. As the solubility decreases (namely, β increases), the stability of the film increases, and the initial surface elasticity also rises. The surface elasticity gradually approaches to the limiting dilational elasticity modulus due to the film being thinner.
Single crystal growth and characterization of the 112-type iron-pnictide EuFeAs2
Authors: Yu Jia  , Liu Tong  , Zhao Kang  , Pan Bo-Jin  , Mu Qing-Ge  , Ruan Bin-Bin  , Ren Zhi-An  ,   Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;,   School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;,   Collaborative Innovation Center of Quantum Matter, Beijing 100190, China
Published: December 2020

The 112-type (Ca, RE)FeAs2 (RE=rare earth) superconductors are very special among the iron-based superconductors for their particular crystal structures with arsenic chain configuration and attractive electronic phase diagram with the coexistence of superconductivity and antiferromagnetism upon carrier doping, while the chemical phases are absent for the low doping level or undoped parent compound. Here we report the single crystal growth method and physical characterizations for the newly discovered Eu 112 type parent compound EuFeAs2. The single crystal of EuFeAs2 is grown by high temperature solution method through using CsCl as the flux under the constant temperature of 800℃ with the molar ratio of the starting materials Eu:Fe:As:CsCl=1:1:4:18. The as-grown crystal is shinyplatelike piece with a typical size of 1 mm1 mm0.2 mm, and quite stable in air. The chemical composition of EuFeAs2 crystal is confirmed by energy-dispersive X-ray spectroscopy. The single crystal X-ray diffraction analysis at room temperature indicates that EuFeAs2 crystallizes into an orthorhombic crystal structure with the space group Imm2 (No. 44), and the refined lattice parameters are a=21.285(9) , b=3.9082(10) , c=3.9752(9) , which are different from those of the Ca 112 compound, but similar to those of unique zigzag As-As chain configuration presented in the layered crystal structure. Electrical resistivity measurements show three anomalies near 110 K, 98 K, and 46 K. The former two anomalies with relatively high temperature imply that the structural and antiferromagnetic transitions are related to Fe2+ sublattice, which is similar to other iron-based parent compounds. The low temperature anomaly at 46 K is attributed to the antiferromagnetic transition of Eu2+ sublattice, which is also confirmed by the corresponding transition observed in the direct current magnetic susceptibility measurement. The magnetic susceptibility of EuFeAs2 exhibits obvious anisotropy blow 46 K when the magnetic field is parallel or perpendicular to the bc plane, while the exact orientation of the Eu2+ moment needs further studying. The discovery of EuFeAs2 provides a new platform for further studying the unique crystal structure and electronic state phase diagrams in the 112-type iron-based superconducting family, and may shed new light on the correlations between superconductivity and magnetism.
Studies of scanning tunneling spectroscopy on iron-based superconductors
Authors: Gu Qiang-Qiang  , Wan Si-Yuan  , Yang Huan  , Wen Hai-Hu  ,   Center for Superconducting Physics and Materials, Department of Physics, Nanjing University, Nanjing 210093, China
Published: December 2020

Since the discovery of iron-based superconductors in 2008, it has been a hot topic to research the pairing mechanism of superconductivity. Scanning tunneling microscopy (STM) can be used to detect the electronic information in nano-scale, hence, it is an important tool to do research on superconductivity. In recent 10 years, many valuable works have been carried out by STM in iron-based superconductors. In this paper, we try to make a brief introduction of the STM works in iron-based superconductors. Since the iron-based superconductors have multiple bands and superconducting gaps, the Fermi surface topology can change significantly among different materials. There are some evidences to prove a nodeless s-wave pairing in the optimally-doped iron-based superconductors with both electron and hole pockets by STM experiments. Furthermore, it has been demonstrated that FeSe-based materials with only electron pockets also have a sign-change order parameter, which provides a robust evidence for the unified picture of the electron pairing in iron-based superconductors. Besides, STM experiments provide fruitful information about the novel electronic properties including the electronic nematicity, shallow band effect, and possible topological superconductivity. Finally, we also give perspectives about the STM studies in iron based superconductors.
Sampling Protocols
Authors: Legacy The Nansen
Published: December 2020

The collection of detailed sampling protocols is crucial tool for the success of the Nansen Legacy, because they ensure:

Methodological agreement between the involved researchers

Continuity and comparable data throughout the 5 years sampling period

An easily accessible overview over parameters sampled

Easier cruise planning
Being Towards Death: Tragic Aesthetics and Stoicism in W. B. Yeats’s Men Improve With The Years
Authors: Tao Shilong
Published: December 2020

Men Improve With The Years was written by W. B. Yeats in 1916 by the time he had turned 50 years old. This paper argues that in this poem, Yeats presents his philosophical thoughts of the tragic life among human beings, highlighting that the joy in tragedy is “the way to survive” while the sorrow in tragedy is “being towards death”. Influenced by Nietzsche’s aesthetic notions of the Apollonian and Dionysian art, Yeats holds a kind of tragic aesthetic view towards death—“the unity of being” of individual life and nature, and aims to seek the joy of growing old and the freedom to create life out of life. As Apollonian dream covers the tragedy of life and Dionysian intoxication discloses it, the nameless old protagonist in the poem or Yeats himself attempts to bear the plight with stoicism and fortitude like a marble Triton so as to conquer and welcome all the sorrows in the process of aging and dying. Since men improve with the years, “being towards death” is the nature of living. Yeats hopes to achieve the aesthetic redemption from the tragic life in his early fifties, thus giving enlightenment to the predicament of human existence.
Interrelation of Character-Generated Implicature and Inter-Character Sentimentality: A Comparison of of Stephenie Meyer’s ‘Twilight’ and Veronica Roth’s ‘Divergent’
Authors: Mohammadpanah Hammed , Hamzehei Samira
Published: December 2020

Inspired by the cognitive approach to characterisation and in view of relevance theory, this research attempted to outline a relevance-theoretic account of how affective attachment between fictional characters influences writers’ use of implicata through characters as part of inter-character discourse by defining cognitive processes into fictional characters as a pivotal element of implicit characterisation. Our attempt addressed the veracity of such an influence and the question whether awareness of the intensity degree of such sentimentality influences readers’ non-spontaneous interpretation of character-generated implicata and characters’ intention to actually execute relevant implicating. By adherence to defining cognitive processes into character discourse, we conducted an analysis on six samples of implicata exchanges within inter-character verbal discourse between the mutual parties of the primary affective attachment of the narrative, between the protagonist and another round character out of Stephenie Meyer’s ‘Twilight’ and Veronica Roth’s ‘Divergent’. In every instance of character-generated implication, we found decisive facilitatory influence for awareness of three levels of calculable implicated conclusions, inter-character sentiment intensity, and characters’ communicative intents on readers' achieving what Furlong terms ‘maximal relevance’ through non-spontaneous interpretation of literary texts. Additionally, tracking the progression of inter-character sentiment intensity throughout the two narratives yielded strategic drops during the gradual formation of inter-character bonds employed mainly to demonstrate a mutual sense of fastidiousness in characters’ choice of a companion in romance and also strengthening the said bonds.
Freeze-Thaw Resistance of Fine-Grained Soils Stabilized with Waste Material Mixtures
Authors: Yarbaşı Necmi , Kalkan Ekrem
Published: December 2020

This paper evaluates the use of waste material mixtures including marble dust and scrap tire rubber the stabilization of fine-grained soils in order to remove the effects of freeze-thaw cycles. In this study, a fine-grained soil material was stabilized by using waste material mixtures. Natural and stabilized fine-grained soil samples were subjected to freeze-thaw cycles under different curing periods. After the freeze-thaw cycles, compressive strength tests were performed to investigate effects of waste material mixtures on the freeze-thaw resistance of fine-grained soil samples. The experimental results showed that the samples of fine-grained soil stabilized with waste material mixtures have high freeze-thaw durability as compared to unstabilized fine-grained soil samples. Consequently, we conclude that waste material mixtures including marble dust and scrap tire rubber, can be successfully used as an additive material to enhance the freeze-thaw durability of fine-grained soils for soil stabilization in the geotechnical applications.
Reliability and validity of the Japanese version of the Gratitude at Work Scale (GAWS)
Authors: Komase Yu , Watanabe Kazuhiro , Sasaki Natsu , Kawakami Norito
Published: December 2020

Objectives

Workplace gratitude is important for improving work-related outcomes and individual well-being. Although the gratitude at work scale (GAWS) was developed in the United States, it has not been corroborated in Asian countries with interdependent cultures. This study aimed to develop and validate the GAWS among Japanese workers.

Method

Japanese workers completed online surveys at baseline (N = 206) and 2 weeks later (N = 103). The Japanese GAWS was developed according to the international guidelines. We measured (a) trait gratitude as comparison for the criterion-related validity, (b) work-related outcomes/factors (eg, work engagement), and (c) well-being (eg, eudemonic well-being at work) as comparisons for convergent validity. Cronbach’s alpha, intra-class correlation coefficients (ICCs), and measurement errors were calculated to assess reliability; measurement validity was evaluated by correlational analyses and confirmatory factor analysis (CFA).

Results

A total of 206 and 93 workers were included for baseline and follow-up analyses, respectively. Cronbach’s alpha and ICCs of the Japanese GAWS ranged from 0.81 to 0.91. CFA showed that the 2-factor model (ie, gratitude for (a) a supportive work environment and (b) meaningful work) demonstrated a good fit (χ2 (34) = 67.58, CFI = 0.967, TLI = 0.956, RMSEA = 0.069, SRMR = 0.037), similar to the original version. As we had hypothesized, overall GAWS and the two domains were significantly correlated with trait gratitude, work-related outcomes/factors, and well-being.

Conclusions

The Japanese GAWS demonstrated good reliability and validity. Future research should explore mechanisms related to workplace gratitude and further intervention studies among workers.
Clinical validation of ring‐mounted halcyon linac for lung SBRT: comparison to SBRT‐dedicated C‐arm linac treatments
Authors: Pokhrel Damodar , Visak Justin , Critchfield Lana C. , Stephen Joseph , Bernard Mark E. , Randall Marcus , Kudrimoti Mahesh
Published: December 2020

Stereotactic body radiotherapy (SBRT) of lung tumors via the ring‐mounted Halcyon Linac, a fast kilovoltage cone beam CT‐guided treatment with coplanar geometry, a single energy 6MV flattening filter free (FFF) beam and volumetric modulated arc therapy (VMAT) is a fast, safe, and feasible treatment modality for selected lung cancer patients. Four‐dimensional (4D) CT‐based treatment plans were generated using advanced AcurosXB algorithm with heterogeneity corrections using an SBRT board and Halcyon couch insert. Halcyon VMAT‐SBRT plans with stacked and staggered multileaf collimators produced highly conformal radiosurgical dose distribution to the target, lower intermediate dose spillage, and similar dose to adjacent organs at risks (OARs) compared to SBRT‐dedicated highly conformal clinical noncoplanar Truebeam VMAT plans following the RTOG‐0813 requirements. Due to low monitor units per fraction and less multileaf collimator (MLC) modulation, the Halcyon VMAT plan can deliver lung SBRT fractions with an overall treatment time of less than 15 min (for 50 Gy in five fractions), significantly improving patient comfort and clinic workflow. Higher pass rates of quality assurance results demonstrate a more accurate treatment delivery on Halcyon. We have implemented Halcyon for lung SBRT treatment in our clinic. We suggest others use Halcyon for lung SBRT treatments using abdominal compression or 4D CT‐based treatment planning, thus expanding the access of curative ultra‐hypofractionated treatments to other centers with only a Halcyon Linac. Clinical follow‐up results for patients treated on Halcyon Linac with lung SBRT is ongoing.
Dopamine transporter imaging predicts clinically‐defined α‐synucleinopathy in REM sleep behavior disorder
Authors: Chahine Lana M. , Brumm Michael C. , Caspell‐Garcia Chelsea , Oertel Wolfgang , Mollenhauer Brit , Amara Amy , Fernandez‐Arcos Ana , Tolosa Eduardo , Simonet Cristina , Hogl Birgit , Videnovic Aleksandar , Hutten Samantha J. , Tanner Caroline , Weintraub Daniel , Burghardt Elliot , Coffey Christopher , Cho Hyunkeun R. , Kieburtz Karl , Poston Kathleen L. , Merchant Kalpana , Galasko Douglas , Foroud Tatiana , Siderowf Andrew , Marek Kenneth , Simuni Tanya , Iranzo Alex
Published: December 2020

Introduction

Individuals with idiopathic rapid eye movement sleep behavior disorder (iRBD) are at high risk for a clinical diagnosis of an α‐synucleinopathy (aSN). They could serve as a key population for disease‐modifying trials. Abnormal dopamine transporter (DAT) imaging is a strong candidate biomarker for risk of aSN diagnosis in iRBD. Our primary objective was to identify a quantitative measure of DAT imaging that predicts diagnosis of clinically‐defined aSN in iRBD.

Methods

The sample included individuals with iRBD, early Parkinson’s Disease (PD), and healthy controls (HC) enrolled in the Parkinson Progression Marker Initiative, a longitudinal, observational, international, multicenter study. The iRBD cohort was enriched with individuals with abnormal DAT binding at baseline. Motor and nonmotor measures were compared across groups. DAT specific binding ratios (SBR) were used to calculate the percent of expected DAT binding for age and sex using normative data from HCs. Receiver operative characteristic analyses identified a baseline DAT binding cutoff that distinguishes iRBD participants diagnosed with an aSN in follow‐up versus those not diagnosed.

Results

The sample included 38 with iRBD, 205 with PD, and 92 HC who underwent DAT‐SPECT at baseline. Over 4.7 years of mean follow‐up, 14 (36.84%) with iRBD were clinically diagnosed with aSN. Risk of aSN diagnosis was significantly elevated among those with baseline putamen SBR ≤ 48% of that expected for age and sex, relative to those above this cutoff (hazard ratio = 17.8 [95%CI: 3.79–83.3], P = 0.0003).

Conclusion

We demonstrate the utility of DAT SBR to identify individuals with iRBD with increased short‐term risk of an aSN diagnosis.
Predictors of Osteonecrosis in Systemic Lupus Erythematosus: A Prospective Cohort Study
Authors: Kallas Romy , Li Jessica , Petri Michelle
Published: December 2020

Objective

We aimed at determining the predictors of osteonecrosis (ON) in a longitudinal lupus cohort.

Methods

Data were reviewed from the initiation of the cohort in 1987 until October 2019. In total, 2,428 patients were included in the analysis based on 224,295 person‐months of follow‐up. We used pooled logistic regression to assess the relationship between risk factors and rates of ON events. After identifying a set of variables related to ON incidence, we fit a final multivariable model to identify the most important risk factors for incident ON.

Results

In 18,691 person‐years of follow‐up after cohort entry, 122 incident ON events were observed (rate = 6.5/1,000 person‐years). In the multivariable analysis, African American patients were at twice the risk for ON compared to White patients. Male patients and smokers had an increased risk for ON of ~80% and 50% compared to female patients and nonsmokers, respectively. For every 10‐year increase in the age at diagnosis, there was a 20% reduced risk for ON. Patients diagnosed after the 1990s had a 50% reduced risk of ON compared to those diagnosed before the 1990s. A highest daily dosage of prednisone of 40 mg or higher, even when administered for a month or less, significantly increased the risk of ON. Use of pulse methylprednisolone or intramuscular triamcinolone was not associated with an increased risk of ON.

Conclusion

African American patients with systemic lupus erythematosus are at double the risk of experiencing ON compared to White patients. Oral prednisone at 20–39 mg for more than 1 month, or 40 mg daily for even 1 month, at any point in the disease course, remained the most important glucocorticoid predictor of ON.