bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlations among atomic mobility, microstructure and local stress of shear bands and necking regions in notched Cu50Zr50 metallic glasses
Authors: Yang Gongji , Wang Mingxu , Kong Lingti , Li Jinfu
Published: September 2019

The atomic mobility, microstructure, and local stress in the shear bands and necking regions of notched Cu50Zr50 metallic glasses are compared, and the intricate interplay among them is examined via molecular dynamics simulations. The virtual tensile tests show that the average atomic mobility inside the mature shear band is lower than that in the necked region, which is controlled by the corresponding atomic-level structure. The short-range topological orders revealed by the Voronoi tessellation of both the necked region and the shear band are, however, quite similar to each other, while the excess free volume of the former is significantly higher than that of the latter. This high free volume content contributes to the migration of atoms or clusters and, thus, expedites the local plastic deformation. Further investigations suggest that the free volume content correlates closely with the local hydrostatic stress, while the topological microstructure is rather insensitive to the hydrostatic stress, especially when the hydrostatic stress is low. In addition, it is also found that the atomic mobility of the central atom in a cluster correlates not only with the local packing environment, such as the free volume content or the hydrostatic stress, but also with the geometry of the cluster, such as its symmetry or coordination number. The findings are helpful in developing/selecting the constitutive models for the deformation of metallic glasses.
Resolved dynamics and subgrid stresses in separating and reattaching flows
Authors: Cimarelli A. , Leonforte A. , De Angelis E. , Crivellini A. , Angeli D.
Published: September 2019

Direct numerical simulation data of the separating and reattaching flow around a blunt bluff body are used for the assessment of the combined role played by the numerical resolution and subgrid turbulence closure in large eddy simulation. The ability of the large-scale resolved field to capture the main flow features is first analyzed. The behavior of the intensity of the resolved fluctuations as a function of the filter lengths reveals a higher sensitivity of the resolved flow on a reduction of resolution in the streamwise direction rather than in the spanwise one. On the other hand, the analysis of the subgrid stresses shows the presence of two challenging phenomena, a reversal of flow of energy from the fluctuating to the mean field in the leading-edge shear layer and a backward energy transfer from small to large scale within the main recirculating bubble. These two phenomena challenge for subgrid closures that should be able to reproduce a flow of energy from the space of small unknown subgrid scales to drive the resolved mean and fluctuating motion. In particular, it is found that the formalism of subgrid viscosity models allows us to capture neither the negative turbulence production of the leading-edge shear layer nor the backward energy transfer within the main flow recirculation. On the other hand, the subgrid similarity models are able to capture both these two phenomena but, from a quantitative point of view, the intensity of the reproduced stresses is very weak. In conclusion, the need of subgrid closures based on a mixed modeling approach for the solution of the flow is envisaged.
Relation between molecular packing and singlet fission in thin films of brominated perylenediimides
Authors: Felter Kevin M. , Dubey Rajeev K. , Grozema Ferdinand C.
Published: September 2019

Perylene diimides (PDIs) are attractive chromophores that exhibit singlet exciton fission (SF) and have several advantages over traditional SF molecules such as tetracene and pentacene; however, their photophysical properties relating to SF have received only limited attention. In this study, we explore how introduction of bulky bromine atoms in the so-called bay-area PDIs, resulting in a nonplanar structure, affects the solid-state packing and efficiency of singlet fission. We found that changes in the molecular packing have a strong effect on the temperature dependent photoluminescence, expressed as an activation energy. These effects are explained in terms of excimer formation for PDIs without bay-area substitution, which competes with singlet fission. Introduction of bromine atoms in the bay-positions strongly disrupts the solid-state packing leading to strongly reduced excitonic interactions. Surprisingly, these relatively amorphous materials with weak electronic coupling exhibit stronger formation of triplet excited states by SF because the competing excimer formation is suppressed here.
Electronic structure and atomic level complexity in Al0.5TiZrPdCuNi high-entropy alloy in glass phase
Authors: Odbadrakh Kh. , Enkhtor L. , Amartaivan Ts. , Nicholson D. M. , Stocks G. M. , Egami T.
Published: September 2019

High entropy alloys (HEAs), or concentrated solid solution alloys, are chemically complex metallic solid solutions in which five or more elements occupy the same crystallographic lattice sites with nearly equal compositions. The high degree of chemical disorder gives rise to considerable local lattice distortions, atomic-level stresses, and complex electronic structure, resulting in interesting properties. We calculated the electronic structure and the atomic-level stresses of AlxTiyZryPdyCuyNiy, x = 0.5, y = 1 (Al0.5TiZrPdCuNi) HEA in the glassy phase using the density functional theory (DFT) approach. We also briefly discuss the electronic structure in its crystalline phase. Whereas it has been reported recently that the crystalline phase of this HEA is obtained as a metastable phase during the crystallization of a glassy phase, the crystalline phase was found to be unstable at T = 0 in the DFT calculation. For this reason, we focus mainly on the glassy phase in this work. The importance of charge transfer among elements on the atomic-level pressure and the role for atomic-level stresses to characterize the electronic and structural heterogeneity are discussed.
Femtosecond real-time probing of the excited-state intramolecular proton transfer reaction in methyl salicylate
Authors: Ling Fengzi , Liu Dejun , Li Shuai , Li Wei , Zhang Bing , Wang Pengfei
Published: September 2019

The excited-state intramolecular proton transfer (ESIPT) process and subsequent electronic relaxation dynamics in methyl salicylate have been investigated using femtosecond time-resolved ion yield spectroscopy combined with time-resolved photoelectron imaging. Excitation with a tunable pump pulse populates the keto tautomer in the first excited electronic state S1(ππ*). As a hydrogen atom transfers from the phenolic group to the carbonyl group within 100 fs, the molecular geometry changes gradually, leading to a variation in the electronic photoionization channel. By virtue of the accidental resonance with some intermediate Rydberg states, the time-dependent photoelectron spectra provide a direct mapping of the ESIPT reaction from the initially populated keto tautomer to the proton-transferred enol tautomer. Subsequently, the population around the enol configuration undergoes intramolecular vibrational redistribution on a subpicosecond time scale, followed by internal conversion to the ground state with a wavelength-dependent lifetime in the picosecond range. Furthermore, the excitation energies of several Rydberg states in methyl salicylate are determined experimentally.
Converting Faraday rotation into magnetization in europium chalcogenides
Authors: van Kooten S. C. P. , Usachev P. A. , Gratens X. , Naupa A. R. , Chitta V. A. , Springholz G. , Henriques A. B.
Published: September 2019

We present a simple semiclassical model to sustain that in europium chalcogenides (EuX), Faraday rotation (FR) in the transparency gap is proportional to the magnetization of the sample, irrespective of the material’s magnetic phase, temperature, or applied magnetic field. The model is validated by FR and magnetization measurements in EuSe in the temperature interval 1.7–300 K, covering all EuSe magnetic phases (paramagnetic, antiferromagnetic type I or type II, ferrimagnetic, and ferromagnetic). Furthermore, by combining the semiclassical model with the explicit electronic energy structure of EuX, the proportionality coefficient between magnetization and FR is shown to be dependent only on the wavelength and the bandgap. Due to its simplicity, the model has didactic value; moreover, it provides a working tool for converting FR into magnetization in EuX. The possible extension of the model to other intrinsic magnetic semiconductors is discussed.
Simultaneous focusing and rotation of a bifunctional thermal metamaterial with constant anisotropic conductivity
Authors: Tsai Yu-Lin , Li Jiangyu , Chen Tungyang
Published: September 2019

We show that a constant anisotropic conductivity tensor can lead to two different functionalities at the same time, thermal focusing or a shielding effect together with a rotating effect. This design is of practical applications, as in energy harvesting and dissipation devices, and it is desirable to concentrate or to shield the thermal energy from a selected direction. We demonstrate that it is possible to control the way that heat flows within a medium to achieve the bifunctional effect solely through a suitable balance among the three material parameters of a homogeneous medium. It is seen that the diagonal entries of the conductivity tensor will govern the thermal focusing or shielding effect, while the off diagonal terms control the rotational effect. To fabricate the designed anisotropic material, we show that the material can be realized via the construction of a layered medium with two alternating isotropic constituents. Theoretical analysis and numerical calculations based on finite element calculations are presented to validate the performance of the design. The use of uniform conductivity to manage heat conduction brings exciting new advances for practical applications, with which one can manipulate thermal energy and offer unprecedented control of heat conduction at the same time.
Face-shear 36-mode magnetoelectric composites with piezoelectric single crystal and Metglas laminate
Authors: Park Sojeong , Peddigari Mahesh , Hwang Geon-Tae , Yoon Woon-Ha , Kumar Ajeet , Ryu Jungho
Published: September 2019

A magnetoelectric (ME) composite is designed with a face-shear 36-mode PMN-PZT single crystal and a Metglas laminate structure to enhance the ME coupling properties and exhibit single resonance behavior over a wide-frequency range. The off resonance and resonance ME voltage coefficients of the designed-composite are high, and approximately 90% similar to those of the 32-mode. While the 32-mode has multiple resonance, the electromechanical and magnetoelectric resonance spectra of the 36-mode composite exhibit only a single resonance over a wide-frequency range from 50 to 200 kHz making it suitable for detecting specific frequency magnetic fields. In addition, it is highly sensitive, being able to detect a magnetic field down to 2 pT at resonance (103 kHz), and therefore has potential to replace conventional bulky and costly magnetic field sensors.
Simultaneous enhancement of spin-torque diode sensitivity and frequency by voltage controlled magnetic anisotropy and parametric synchronization
Authors: Sisodia Naveen , Muduli P. K.
Published: September 2019

We propose a method for simultaneous enhancement of the Radio Frequency (RF) detection sensitivity and the detection frequency of a Magnetic Tunnel Junction (MTJ) by utilizing voltage controlled magnetic anisotropy (VCMA) and the technique of parametric synchronization. We show that the presence of VCMA enhances the coupling strength of parametric synchronization by ∼40 times, giving a very high sensitivity of the order of 105 mV/mW. We discuss the detailed field, bias, external RF power, and temperature dependence of the phenomenon for optimization of MTJ based detectors. The results will be useful for realizing highly sensitive RF detectors with high detection frequency working at low input powers.
Multidecadal observations of the Antarctic ice sheet from restored analog radar records
Authors: Schroeder Dustin M. , Dowdeswell Julian A. , Siegert Martin J. , Bingham Robert G. , Chu Winnie , MacKie Emma J. , Siegfried Matthew R. , Vega Katherine I. , Emmons John R. , Winstein Keith
Published: September 2019

Airborne radar sounding can measure conditions within and beneath polar ice sheets. In Antarctica, most digital radar-sounding data have been collected in the last 2 decades, limiting our ability to understand processes that govern longer-term ice-sheet behavior. Here, we demonstrate how analog radar data collected over 40 y ago in Antarctica can be combined with modern records to quantify multidecadal changes. Specifically, we digitize over 400,000 line kilometers of exploratory Antarctic radar data originally recorded on 35-mm optical film between 1971 and 1979. We leverage the increased geometric and radiometric resolution of our digitization process to show how these data can be used to identify and investigate hydrologic, geologic, and topographic features beneath and within the ice sheet. To highlight their scientific potential, we compare the digitized data with contemporary radar measurements to reveal that the remnant eastern ice shelf of Thwaites Glacier in West Antarctica had thinned between 10 and 33% between 1978 and 2009. We also release the collection of scanned radargrams in their entirety in a persistent public archive along with updated geolocation data for a subset of the data that reduces the mean positioning error from 5 to 2.5 km. Together, these data represent a unique and renewed extensive, multidecadal historical baseline, critical for observing and modeling ice-sheet change on societally relevant timescales.
Market-mediated responses confound policies to limit deforestation from oil palm expansion in Malaysia and Indonesia
Authors: Taheripour Farzad , Hertel Thomas W. , Ramankutty Navin
Published: September 2019

Significance

The rapid expansion of oil palm in Malaysia and Indonesia (M&I) has contributed to record levels of deforestation, carbon emissions, and biodiversity loss. Sustainability certification schemes seeking to address this problem have fallen short of their stated goals, leading to calls for more aggressive measures. Here we explore 3 alternative conservation policies within a global economic framework and find that market-mediated responses confound the efficacy and distributional impacts of these policies. We suggest that simply limiting palm oil production or consumption is unlikely to halt deforestation in M&I in the absence of active forest conservation incentives. We also find that M&I would benefit economically by taking domestic action rather than waiting for others to act.
The genetic landscape of Scotland and the Isles
Authors: Gilbert Edmund , O’Reilly Seamus , Merrigan Michael , McGettigan Darren , Vitart Veronique , Joshi Peter K. , Clark David W. , Campbell Harry , Hayward Caroline , Ring Susan M. , Golding Jean , Goodfellow Stephanie , Navarro Pau , Kerr Shona M. , Amador Carmen , Campbell Archie , Haley Chris S. , Porteous David J. , Cavalleri Gianpiero L. , Wilson James F.
Published: September 2019

Significance

Modern genetic analysis has revealed genetic differentiation across the south of Britain and Ireland. This structure demonstrates the impact of hegemonies and migrations from the histories of Britain and Ireland. How this structure compares to the north of Britain, Scotland, and its surrounding Isles is less clear. We present genomic analysis of 2,544 British and Irish, including previously unstudied Scottish, Shetlandic and Manx individuals. We demonstrate widespread structure across Scotland that echoes past kingdoms, and quantify the considerable structure that is found on its surrounding isles. Furthermore, we show the extent of Norse Viking ancestry across northern Britain and estimate a region of origin for ancient Gaelic Icelanders.
Discovery of novel bacterial queuine salvage enzymes and pathways in human pathogens
Authors: Yuan Yifeng , Zallot Rémi , Grove Tyler L. , Payan Daniel J. , Martin-Verstraete Isabelle , Šepić Sara , Balamkundu Seetharamsingh , Neelakandan Ramesh , Gadi Vinod K. , Liu Chuan-Fa , Swairjo Manal A. , Dedon Peter C. , Almo Steven C. , Gerlt John A. , de Crécy-Lagard Valérie
Published: September 2019

Queuosine (Q) is a complex tRNA modification widespread in eukaryotes and bacteria that contributes to the efficiency and accuracy of protein synthesis. Eukaryotes are not capable of Q synthesis and rely on salvage of the queuine base (q) as a Q precursor. While many bacteria are capable of Q de novo synthesis, salvage of the prokaryotic Q precursors preQ
0
and preQ
1
also occurs. With the exception of
Escherichia coli
YhhQ, shown to transport preQ
0
and preQ
1
, the enzymes and transporters involved in Q salvage and recycling have not been well described. We discovered and characterized 2 Q salvage pathways present in many pathogenic and commensal bacteria. The first, found in the intracellular pathogen
Chlamydia trachomatis
, uses YhhQ and tRNA guanine transglycosylase (TGT) homologs that have changed substrate specificities to directly salvage q, mimicking the eukaryotic pathway. The second, found in bacteria from the gut flora such as
Clostridioides difficile
, salvages preQ
1
from q through an unprecedented reaction catalyzed by a newly defined subgroup of the radical-SAM enzyme family. The source of q can be external through transport by members of the energy-coupling factor (ECF) family or internal through hydrolysis of Q by a dedicated nucleosidase. This work reinforces the concept that hosts and members of their associated microbiota compete for the salvage of Q precursors micronutrients.
A tryptophan synchronous and normal fluorescence study on bacteria inactivation mechanism
Authors: Li Runze , Dhankhar Dinesh , Chen Jie , Cesario Thomas C. , Rentzepis Peter M.
Published: September 2019

Significance

The inactivation of bacteria by UV light involves sequential dynamic processes that occur from femtoseconds to minutes and span from simple molecules to proteins and organisms. Detailed understanding of the inactivation mechanism is important and the key to efficient inactivation of harmful pathogens whose antibiotic resistance is critically increasing. In this study, we show that, for
Escherichia coli
and
Bacillus subtilis
bacteria, their tryptophan fluorescence intensity increased within the first minute of UV irradiation and subsequently decreased continuously. These data suggest that, shortly after exposure to UV light, tryptophan may be released from the bacterial membrane and protein unfolding which contributes to the increased tryptophan fluorescence intensity. This study provides a further means for monitoring the rate of bacteria inactivation.
YAP and TAZ regulate cell volume
Authors: Perez-Gonzalez Nicolas A. , Rochman Nash D. , Yao Kai , Tao Jiaxiang , Le Minh-Tam Tran , Flanary Shannon , Sablich Lucia , Toler Ben , Crentsil Eliana , Takaesu Felipe , Lambrus Bram , Huang Jessie , Fu Vivian , Chengappa Pragati , Jones Tia M. , Holland Andrew J. , An Steven , Wirtz Denis , Petrie Ryan J. , Guan Kun-Liang , Sun Sean X.
Published: September 2019

How mammalian cells regulate their physical size is currently poorly understood, in part due to the difficulty in accurately quantifying cell volume in a high-throughput manner. Here, using the fluorescence exclusion method, we demonstrate that the mechanosensitive transcriptional regulators YAP (Yes-associated protein) and TAZ (transcriptional coactivator with PDZ-binding motif) are regulators of single-cell volume. The role of YAP/TAZ in volume regulation must go beyond its influence on total cell cycle duration or cell shape to explain the observed changes in volume. Moreover, for our experimental conditions, volume regulation by YAP/TAZ is independent of mTOR. Instead, we find that YAP/TAZ directly impacts the cell division volume, and YAP is involved in regulating intracellular cytoplasmic pressure. Based on the idea that YAP/TAZ is a mechanosensor, we find that inhibiting myosin assembly and cell tension slows cell cycle progression from G1 to S. These results suggest that YAP/TAZ may be modulating cell volume in combination with cytoskeletal tension during cell cycle progression.
A Defense of Low-Probability Scientific Explanations
Authors: Clatterbuck Hayley
Published: September 2019

I evaluate the plausibility of explanatory elitism, the view that a good scientific explanation of an outcome will show that it was highly probable. I consider an argument from Michael Strevens that elitism is the only view that can account for the historical acceptance of probabilistic theories in physics. I argue that biology provides better test cases for evaluating elitism and conclude that theories in that domain were favored in virtue of conferring correct, and not necessarily high, probabilities on outcomes.
Actual Causation and Compositionality
Authors: Livengood Jonathan , Sytsma Justin
Published: September 2019

Many theories of actual causation implicitly endorse the claim that ifcis an actual cause ofe, then eitherccausesedirectly or every intermediary by whichcindirectly causeseis itself both an actual cause ofeand also an actual effect ofc. We think this compositionality constraint is plausible. However, as we show, it is not always satisfied by the causal attributions ordinary people make. We conclude by considering what philosophers working on causation should do when the deliverances of their theories diverge from what ordinary people say.
Discrimination of different cell monolayers before and after exposure to nanosecond pulsed electric fields based on Cole–Cole and multivariate analysis
Authors: Shi Fukun , Zhuang Jie , Kolb Juergen F
Published: September 2019

Normal and cancer cells, which were grown in monolayers, were investigated and discriminated by electrical bioimpedance spectroscopy (EBIS) before and after exposures to nanosecond pulsed electric fields (nsPEFs). Bioimpedance data were analysed with a Cole–Cole model and the principal component analysis (PCA). Normal and cancer cells could be clearly distinguished from each other either from Cole parameters (R
0, α, τ) or from two dominant principal components. The trend of changes for Cole parameters indicated distinctively different post-nsPEF-effects between normal and cancer cells. PCA was also able to distinguish characteristic impedance spectra 30 min after exposures. The first principal component suggested that post-nsPEF-effects for normal cells were revealed especially at lower frequencies. The results indicated further that the extracellular resistance, which is dominated by cell–cell connections, might be an important factor with respect to selective nsPEF-effects on cancer cells that are organized in a monolayer or a tissue, respectively. Accordingly, the results support the application of EBIS as an early, non-invasive, label-free, and time-saving approach for the classification of cells to provide in particular predictive information on the success of cancer treatments with nsPEFs.
Classical mechanics of the Hydrogen atom perturbed by Van der Waals potential interacting with combined electric and magnetic fields
Authors: Chatar W , Benkhali M , El Fakkousy I , Kharbach J , Rezzouk A , Ouazzani-Jamil M
Published: September 2019

The hydrogen atom perturbed by Van der Waals potential interacting with combined electric and magnetic fields is a non-integrable system, except for some cases, one of which is separable in elliptical coordinates. A detailed study of the classical mechanics of the system is presented giving a complete description of the real phase space structure of the system, we also determine all the generic bifurcations of Liouville tori. This study is supported by numerical investigations via the Poincare surface of section and the phase space trajectories method. The dynamic character of this system depends on the van der Waals potential and the intensity of the magnetic field. Numerical calculations show that if the separability condition is verified, the classical dynamics is regular. However, with a small change in the condition, the dynamic property of the hydrogen atom begins to change. Since the condition is far from integrable behavior, almost all phase space trajectories are chaotic. On the other hand, the intensity of the electric field has no influence on the system.
X-ray diffraction investigations of nanostructured ZnO coated with reduced graphene oxide.
Authors: Boukhoubza I , Khenfouch M , Achehboune M , Mothudi B M , Zorkani I , Jorio A
Published: September 2019

Nowdays, nanocomposites containing ZnO with various morphologies and graphene, graphene oxide (GO) or reduced graphene oxide (rGO) have been attracting many researchers according to their properties and board application in optoelectronic devices. In this study, rGO/ZnO nanorods were synthesized using different procedures. In the first procedure, ZnO nanorods prepared by using the hydrothermal method. In the second procedure, the surface of ZnO nanorods was coated with rGO using the drop coating process. The pure ZnO, rGO and rGO/ZnO nanorods were characterized by X-ray diffraction (XRD) and the average crystallite size was calculated using Debye-Scherrer equation.
Electronic and magnetic properties of Ni2MnGa: Monte-Carlo and ab-initio calculations
Authors: Boughlala A. , Benzakour N. , Hourmatallah A. , Bouhou S. , Salmi S. , Bouslykhane K.
Published: September 2019

This paper describes computational calculations based on the density functional theory (DFT), in order to investigate the electronic and magnetic properties of Ni2MnGa alloys. The local density approximation (LDA) and generalized gradient approximation (GGA) methods were used, which are implemented in the MACHIKANEYAMA package designed and made by Akai [1]. As result, we found that the alloys possess a ferromagnetic behaviour with magnetic moment of 4,07μB/cell. The analysis of the density of states (DOS) shows that the alloys have a half-metallic behaviour due to the Mn-d and Ni-d states crossing the Fermi level. Moreover, the Monte-Carlo simulation method in the framework of the Ising model gives the magnetization and the susceptibility values, respectively.
Vacancies effect on graphene: Raman study
Authors: Ait Abdelkader S A , Boutahir O , Boutahir M , Fakrach B , Bentaleb M , Rahmani AH , Chadli H , Rahmani A
Published: September 2019

The acid oxidation treatment methods have been widely reported as an effective method to purify and functionalize the surface of graphene. Although effective, the strong acids typically employed may cause graphene extra-damage, limiting its potential. This work examines the use of a concentrated HNO3/H2SO4 mixture in dispersing graphene in aqueous sulfactant solutions. Raman spectroscopy can be used to provide a rapid and non-destructive analysis to estimate the concentration of defect created by acid in graphene. The X-ray diffraction (XRD) was used to compare the patterns as a function of the acid concentration used in thin films. The Raman measurements were performed on graphene deposited on Si substrates. The first-order resonance Raman scattering mechanisms in graphene with defects were analysed considering the origin of the G and D bands. In the other hand, the acid can probably creat the vacancies defects on grapheme. Then, we calculate Raman spectra of graphene with mono, di and tri-vacancies defects as function of the concentrations of such defects. The obtained results we observed that the D band appeared, the results are coherent and in agreement with the experimental analysis.
The influence of solution temperature of SnS thin films grown by successive ionic layer adsorption and reaction (SILAR) method
Authors: Qachaou Y , Daoudi O , Raidou A , Lharch M , Qachaou A , Fahoume M
Published: September 2019

Tin sulfide is a promising optoelectronic material, which has a particular interest due to its absorption coefficient, direct (indirect) bandgap and its non-toxic components. SnS thin films were deposited on glass substrates by SILAR (Successive Ionic Layer Adsorption and Reaction) method at different solutions temperatureand it is rarely developed by this parameter. The cationic (SnCl2.2H2O) and anionic (Na2S.9H2O) solutions were used as precursors materials. The structure, films composition, morphology, and optical properties were investigated by using X-ray diffraction, Raman spectroscopy, energy dispersive X-ray analysis, Scanning electron microscopy (SEM) and spectrophotometer. X-ray diffraction (XRD) patterns indicated that the deposited SnS thin films have an orthorhombic crystal structure. Raman spectroscopy confirmed the presence of the SnS phase. Uniform deposition of the material over the entire glass substrate was showed by Scanning electron microscopy (SEM). The optical band gap energy was found between 1.6 and 1.85 eV.
Analysis and Portrait of College Students’ Online Behavior Habits
Authors: Jiang Yupeng , Zhao Yingying , Xu Hui
Published: September 2019

In the era of information technology, the popularity of college networks has brought great convenience to students. However some students indulge in the network and thus affect the quality of learning. In order to help college students make use of network resources properly, we analyze students’ surfing behavior from the perspective of data mining. 11 classes of web pages with high degree of attention are taken into consideration. the data of more than 100 million log records generated by students in universities within 20 days are collected. We also use Bisecting K-means algorithm to cluster students on different levels. For measuring every students’ behavior, we introduce a stability measure for web surfing behavior. we calculate this parameter for every student and analyse the results. Finally, according to the clustering results, cluster stability analysis results and other attributes, we draw a user portrait for every student. After practice, the method is simple and easy to use, providing reference for universities to organize network management activities and standardizing college students’ online behavior.
Design and Implementation of Information Management System for Rice
Authors: Fan Rongrong , Xu Hui , Zhao Yingying
Published: September 2019

In order to strengthen the management of the quality and safety of agricultural products, to rice as the object, based on the rice production and supply chain, this paper designs an information management system for rice. Using. Net platform, MVC4 framework and other technologies for the construction and development of the system, to achieve the rice from cultivation to sales of the whole process of information management, effectively strengthen the supervision of the quality and safety of rice; The data were processed and analyzed, and the prediction of rice yield was realized by multiple linear regression algorithm, which promoted the process of modern agricultural informatization.
RETRACTED: On The Development of Healthy Tourism Industry in Shandong Province Under The Background of Big Data
Authors: Guo Ranran
Published: September 2019

As the important convergence point of people’s livelihood improvement and economic development, “medical and health industry” is one of the emerging industries in the “top ten” industries to support the Major Project for Transforming Old and New Driving Forces in Shandong province. Developing healthy tourism industry is conducive to promoting the construction of “Healthy Shandong” and accelerating the transformation of old and new driving forces. Besides the advantage of natural resources for developing healthy tourism, a series of policies, such as Shandong Province Healthy Tourism Industry Development Plan (2018-2022), provide a good opportunity and platform for Shandong healthy tourism to explore the domestic and international markets. At present, many problems have been exposed for developing Shandong Healthy Tourism industry, including that the provincial medical health industry is still in its infancy, the industry is big but not strong, the industry structure is no reasonable, regional differentiation is not obvious enough, leading enterprises and well-known brands are few, the application of new technology is insufficient, the support OF HR is not strong, and cross-border integration needs to be deepened. It is suggested that the government ought to make rational use of big data to strengthen the top-level design, innovate developing models, promote quality improvement and capacity expansion, strengthen intellectual security, and establish brand image.
Optimization of Three - Frame Difference Method and Improvement of Pedestrian Detection Code Book
Authors: Shang Lei , You Fucheng , Han Chao , Wang Xuewei , Zhao Shuai
Published: September 2019

Pedestrian detection is one of the most important applications of computer vision. In this paper, aiming at the problem of poor anti-interference ability of traditional codebook algorithm in the complex background and the cavity-prone problem of traditional frame difference method, a pedestrian detection algorithm integrating the optimized frame difference method and improved codebook is proposed. In this algorithm, a double code word structure is designed. An update mechanism is added to the code words in the codebook background modeling process and detection process, and improved double code word book algorithm based on YUV color space is designed to realize the real-time background update function. After that, bilateral filtering is added to the traditional three-frame difference method to further remove the noise. At the same time, the extracted rectangular region is used for filling operation and morphological processing to obtain the corresponding foreground image. Finally, the foreground image of codebook model and the foreground image of frame difference method are calculated with “and”, “different or” and “or” of pixels to obtain the precise region of moving target. The experimental results show that this algorithm combines the advantages of the two methods and abandons the disadvantages of each method in the detection prospect. It can accurately detect moving targets and has good robustness. The effectiveness of this algorithm is also verified by experiments.
Camshift Algorithm Combined with Contour Coordinate Point Target Tracking
Authors: Han Chao , You Fucheng , Zhao Shuai , Wang Shaomei
Published: September 2019

Aiming at the deficiency of traditional CamShift algorithm in losing targets easily in video sequence of background with color similarity, this paper explores the reasons of losing targets, gives the numerical requirements to ensure that targets are followed precisely and proposes a target tracking algorithm combining contour coordinate points. The algorithm modifies the tracking window according to the coordinate points of the target contour, so as to obtain the size and position of the target in the current image and improve the tracking stability. The experimental results show that the target can be tracked effectively under the interference of color similarity background.
Link Prediction for Complex Networks via Random Forest
Authors: Li Kuanyang , Tu Lilan
Published: September 2019

In this paper, based on four existing similarity indexes (CN, LHN-II, COS+ and MFI), we obtain eigenvectors by extracting the features of two arbitrary complex network nodes. The core idea of this paper is to use decision trees to handle these four different indexes which are not strongly related. After training and learning with the random forest algorithm, a new link prediction algorithm for complex networks is proposed. We prove by conducting some numerical simulations, using the US aviation network as an example, that the proposed link prediction algorithm is more accurate and stable than other similar algorithms.
On Massive JSON Data Model and Schema
Authors: Lv Teng , Yan Ping , He Weimin
Published: September 2019

JSON (JavaScript Object Notation) is a lightweight semi-structured data format based on the data types of programming language JavaScript. It is a popular data exchange format over the World Wide Web and becomes a dominant standard format for sending API (Application Programming Interface) requests and responses in the past few years. Furthermore, JSON has also attracted attentions of database community research, especially in data intensive applications. JSON is not only can be integrated in traditional database systems, but also widely used in NoSQL database systems and graph database systems. Compared with XML, JSON document is a set of “key-value” pairs, in which the “value” itself can be a JSON document, which allows arbitrary levels of nesting, so it is more flexible to use and more difficult to process accordingly. JSON data model and schema describe the basic data structures and semantics of the underlying JSON data, so it is the fundamental and key aspects for JSON data format. JSON data model and schema are not only foundations for other data management technologies, such as data indexing, data querying, data searching, data mapping, data integrating, and data mining, but also has important theoretical significance and application prospects to provide theoretical basis and technical means for other related research, such as data integration, data conversion and other semi-structured and unstructured data queries. This paper analyzes the key problems of JSON data model and schema, including what data model should adopted by JSON and the specification and schema outline of JSON model.
A MapReduce-Based Parallel Mining for Frequent Itemset
Authors: Liu Nian , Guo Jinxu
Published: September 2019

Frequent itemset mining is the most important step of association rule mining. Due to the large size of datasets, many parallel mining methods have been introduced to divide datasets or to distribute mining processes, which improve the efficiency of mining. In this paper, we propose a parallel algorithm of PrePost+ based on MapReduce (we call our parallel algorithm MR-PrePost+) to mine frequent itemsets. In our parallelization approach, the Reduce task performs a set of independent mining tasks, which eliminates data dependencies and computational dependencies between machines. The experimental results show that our MapReduce-based parallel algorithm MR-PrePost+ performs better than PFP in running time, which is one of the best frequent itemset mining parallel algorithms.
Deceiving Face Recognition Neural Network with Samples Generated by Deepfool
Authors: Xue Jingsong , Yang Yu , Jing Dongsheng
Published: September 2019

Image-based identity authentication systems have been extensively used recently. However, it holds the risk of illegal use of the images for authentication by others, which will cause a severe threat to personal privacy and security protection. The concept of adversarial samples, which is often utilized in the field of deep learning to deceive classification models, has become more and more popular, and has accumulated lots of significant efforts. Meanwhile, previous work mainly focused on interpreting images by features rather than by the structural characteritics of the human face, which made the deception of face recognition model ineffective. To solve the problem, face recognition neural network deceiving method that is based on Deepfool algorithm is proposed. For a specific face recognition neural network, white-box attack is used to generate adversarial samples, and Euclidean distance is utilized to optimize adversarial samples to obtain face photos with misleading attributes. The proposed approach can be used for privacy and security protection. Experiments on several face testing data sets verify effeteness of our proposed approach.
Automatic Message Forwarding System Based on Directional Transmission Networking
Authors: Xu Zhengqin , Zhao Wendong , Peng Laixian , Chu Xiaojing
Published: September 2019

With the rapid development of multi-functional radio frequency technology and software radio technology, radar has become an independent node of wireless communication, which can make multi-platforms form the function of ad hoc network. This paper designs and implements an automatic message forwarding system based on directional transmission networking. The prominent feature is directional transmission. Secondly, information processing and forwarding are accomplished based on algorithm structure. This system can realize the functions of radar wireless ad hoc network, mutual detection and target information fusion, and enhance the flexibility of equipment.
On Computer Digital Illustration Design
Authors: Liu Yongqing
Published: September 2019

The text mainly analyzes digital method, expression style and creativity of computer digital illustration from the perspective of modern design development. With the dramatic development of digital technology and computer network popularization, it reveals that illustration design gains great technical support. Artistic thoughts and ideas also win the new release, which generates a new visual experience for individuals. Digital illustration has become the most appealing and fashionable art form in this era.
Resource Usage Evaluation Study in HPC Cluster
Authors: Guo Jiaxu , Xu Gaochao , Fu Xiaodong , Li Yang , Liu Peng
Published: September 2019

In order to evaluate the running state of computing clusters, this paper proposes a measure index for evaluating the resource utilization of nodes in high-performance computing clusters -- Load Score of Computing Node(LSCN), and compares two methods for determining parameter weights, principal component analysis (PCA) and entropy weight determination method (EWD), in combination with relevant algorithms in the field of machine learning, so as to provide useful guidance for the running and maintenance of computing clusters.
OpenGL based A 3D Visual Technology of Digital Core
Authors: Huang Rui , Zan Cheng , Long Wei , Cheng Haoran , Li Wei , Wang Guanqun , Zhang Bing
Published: September 2019

OpenGL is widely used in many industrial application fields as a powerful 3D graphics library. Especially, it plays important roles in displaying the visualization emulation model of digital cores. In this paper, according to the practical demands of projects, we conduct a thorough research on displaying 3D visual models of the pore structure and the skeleton structure of digital cores using OpenGL application library. Actual applications indicate that the idea of this paper is feasible and it holds the keys to scientific research of digital cores.
A Network Selection Method Based on Q-Learning in Power Wireless Communication System
Authors: Shao Gang , Wu Wenqin , Yin Lei , Ding Chenyang
Published: September 2019

In power wireless communication network, the traditional network selection algorithm can’t deal with the problem of dynamic selection according to network condition, so this paper proposes a network selection algorithm based on Q-learning. Q-learning algorithm is a model-free reinforcement learning algorithm, which is often applied in the field of wireless communication due to its flexibility and adaptability, and obtains the optimal strategy by the Q-value function estimation of state-action pair. In this paper, we establish the Q-learning network selection model, determine the network status in the analysis of network load and service type, then select the maximum cumulative rewards to the action, with which we can select the optimal network. Since the Q value of the Q-learning algorithm is updated iteratively, the algorithm can adapt to the dynamic network selection. The simulation results show that the network selection algorithm based on Q-learning can effectively reduce the blocking rate of voice traffic and data packet loss rate, and improve the average network throughput.
Fusion Image Style Transfer Network
Authors: Lai Shuren , You Fucheng , Gong Hechen , Zhao Yangze
Published: September 2019

Generating art automatically and quickly for machines is always a difficult task. The existing image style migration algorithms can realize the rapid generation of art images. However, these algorithms can only generate artistic images by migrating existing content maps, and can not modify the content of images artificially. This paper proposes an image style migration approach which can stylize artificially modified fusion image. Particularly, this strategy can correct the modification of the photographic images and enhance the style shifting details. Aiming at eliminating traces of modification, we adopt a autoencoder network to increase fusion image coordination. This network increases detail representation of fusion image. In order to enhance visual effects of style migration, we improve a neural style migration network to generate fusion image stylized graph. We show that this approach make the fused image more coordinated, resulting in a richer detail of the style image.
Vehicle detection in aerial image based on deep learning
Authors: Zhao Shuai , You Fucheng , Shang Lei , Han Chao , Wang Xuewei
Published: September 2019

At present, urban traffic congestion is becoming more and more serious. Traditional vehicle detection methods generally have problems of low precision and low recognition rate. In order to solve these problems, a vehicle detection method in aerial image based on deep learning is proposed. The method uses the YOLOv3 algorithm and optimizes the algorithm network, increase the number of rasters of the final predicted output, improves the detection ability of the network for dense groups, and verifies the effect by training a new model. The experimental results show that the new training model has a good effect on vehicle detection, which solves the problem of low detection and recognition rate of urban traffic vehicle detection, and makes good predictions and judgments on urban traffic congestion.
Cross-Modulated Amplitudes and Frequencies of Epileptic EEG
Authors: Cai Yujie , Dai Jiafei , Li Jin , Wang Jun , Hou Fengzhen
Published: September 2019

Epilepsy is a neural disorder with the hallmark of recurrent seizures. To characterize the epileptic brain electrical activities, we employed the cross modulation of instantaneous amplitudes and frequencies to separate synchronous and anti-synchronous modulation. Amplitude-amplitude, amplitude-frequency and frequency-frequency cross modulation were adopted to analyse the difference between EEG signal of epileptic patients and that of normal people. By comparing the observed patterns with two groups of EEG signals we demonstrate that the cross-modulation exponentials at the temporal region and the occipital region of right hemisphere are significant different.
Fuzzy Twin Support Vector Machine Based on Intra-class Hyperplane
Authors: Zhang Hanghang , Li Haipeng
Published: September 2019

Aiming at the sensitivity of twin support vector machines to noise and outliers, an improved fuzzy twin support vector machine is proposed. Aiming at the shortcomings of fuzzy membership based on the distance between a sample and its class center, this algorithm proposes a new fuzzy membership function that can effectively reflect sample uncertainty— based on intra-class hyperplane and sample affinity. When determining the membership function, the intra-class hyperplane replaces the class center, reducing the dependence on the sample set geometry and improving the model generalization ability. At the same time, considering the relation between each sample and the confusion degree of sample points, the sample affinity is applied to the design of membership function, so as to effectively distinguish the effective sample from noise and outliers and improve the classification accuracy. The experimental results show that compared with the twin support vector machine and the classic fuzzy support vector machine, the improved fuzzy twin support vector machine has better classification performance.