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Computational modeling sheds light on structural evolution in metallic glasses and supercooled liquids

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npj Computational Materials 2017年第1期3卷 405-416页

作者： Jun Ding en Ma Materials Sciences Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Department of Materials Science and engineering Johns Hopkins UniversityBaltimoreMD 21218USA

This article presents an overview of three challenging issues that are currently being debated in the community researching on the evolution of amorphous structures in metallic glasses and their parent supercooled *** emphasis is on the valuable insights acquired in recent computational analyses that have supplemented experimental *** first idea is to use the local structural order developed,and in particular its evolution during undercooling,as a signature indicator to rationalize the experimentally observed temperature-dependence of viscosity,hence suggesting a possible structural origin of liquid *** second issue concerns with the claim that the average nearest-neighbor distance in metallic melts contracts rather than expands upon heating,concurrent with a reduced coordination *** postulate is,however,based on the shift of the first peak maximum in the pair distribution function and an average bond length determined from nearest neighbors designated using a distance *** can instead be a result of increasing skewness of the broad first peak,upon thermally exacerbated asymmetric distribution of neighboring atoms activated to shorter and longer distances under the anharmonic interatomic interaction *** third topic deals with crystal-like peak positions in the pair distribution function of metallic *** peak locations can be explained using various connection schemes of coordination polyhedra,and found to be present already in high-temperature liquids without hidden crystal *** also present an outlook to invite more in-depth computational research to fully settle these issues in future,and to establish more robust structure-property relations in amorphous alloys.

关键词： metallic glasses structural

Modeling and Predicting of News Popularity in Social Media Sources

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Computers, Materials & Continua 2019年第7期61卷 69-80页

作者： Kemal Akyol BahaŞen Faculty of engineering and Architecture Kastamonu University37100KastamonuTurkey Faculty of engineering Yıldırım Beyazıt University06500AnkaraTurkey

The popularity of news,which conveys newsworthy events which occur during day to people,is substantially important for the spectator or *** interact with news website and share news links or their *** study uses supervised learning based machine learning techniques in order to predict news popularity in social media *** techniques consist of basically two phrases:a)the training data is sent as input to the classifier algorithm,b)the performance of prelearned algorithm is tested on the testing *** so,a knowledge discovery from the data is *** this context,firstly,twelve datasets from a set of data are obtained within the frame of four categories:Economic,Microsoft,Obama and ***,news popularity prediction in social network services is carried out by utilizing Gradient Boosted Trees,Multi-Layer Perceptron and random Forest learning *** prediction performances of all algorithms are examined by considering Mean Absolute Error,root Mean Squared Error and the r-squared evaluation *** results show that most of the models designed by using these algorithms are proved to be applicable for this ***,a comprehensive study for the news prediction is presented,using different techniques,drawing conclusions about the performances of algorithms in this study.

关键词： News popularity sentiment scores social network services Gradient Boosted Machines Multi-Layer Perceptron random Forest

Min-max partitioning problem with matroid constraint

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2008年第10期9卷 1446-1450页

作者： Biao WU en-yu YAO Department of Mathematics Zhejiang University Hangzhou 310027 China

In this paper, we consider the set partitioning problem with matroid constraint, which is a generation of the k-partitioning problem. The objective is to minimize the weight of the heaviest subset. We present an approximation algorithm, which consists of two sub-algorithms-the modified Edmonds' matroid partitioning algorithm and the exchange algorithm, for the problem. An estimation of the worst ratio for the algorithm is given.

关键词： Matroid Matroid partition Worst ratio

Application of an ice-ocean coupled model to Bohai Sea ice simulation

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Journal of Oceanology and Limnology 2021年第1期39卷 1-13页

作者： Bin JIA Xue’en CHen College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdao 266100China

The HAMSOM(Hamburg Shelf Ocean Model),a high-resolution regional ice-ocean coupled model,was applied to investigate the seasonal evolution of Bohai Sea ice for winter 2015/*** was initialized with monthly climatological temperature and salinity data from WOA13 and driven by hourly meteorological data obtained from the NCEP above the sea surface and tides at the open *** ice model used here is a modifi ed Hibler-type dynamic-thermodynamic sea ice model based upon viscous-plastic *** ice extent,concentration,area,thickness,length of ice season as well as the distance between the top of Liaodong Bay(North China)and the outer ice edge line were simulated and compared with the observed *** types of modeling experiments were carried out to investigate the eff ects of wind,tide,and both wind and tide on Bohai Sea *** results show that wind,as both a dynamic and a thermodynamic factor,has a signifi cant impact on the ice thickness,ice area,and ice-freezing and ice breakup dates as well as the ice velocity,while tides are a dynamic factor that infl uences only the ice *** the severe ice period,the wind speed intensity increased by 25%,the average ice thickness thickened by approximately 4.0 cm in Liaodong Bay,approximately 2.1 cm in Bohai Bay and approximately 2.5 cm in Laizhou Bay,and the total ice coverage area and total ice actual area increased by about 2×104 km 2 and 1.4×104 km 2,*** the tidal amplitude intensity increased by 25%,the average ice velocity increased by approximately 0.1 m/s.

关键词： Bohai Sea ice ice-ocean coupled model eff ects of wind and tides

energy-resolved spin filtering effect and thermoelectric effect in topological-insulator junctions with anisotropic chiral edge states

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Frontiers of physics 2022年第6期17卷 85-93页

作者： Jia-en Yang Hang Xie School of Electronics and IoT Chongqing College of Electronic EngineeringChongqing 401331China College of Physics Chongqing UniversityChongqing 401331China Chongqing Key Laboratory for Strongly-Coupled Physics Chongqing UniversityChongqing 401331China

Topological edge states have crucial applications in the future nano spintronics *** this work,circularly polarized light is applied on the zigzag silicene-like nanoribbons resulting in the anisotropic chiral edge *** energy-dependent spin filter is designed based on the topological-insulator(TI)junctions with anisotropic chiral edge *** resonance transmission has been observed in the TI junctions by calculating the local current *** some strong Fabry–Perot resonances are found leading to the sharp transmission ***,the weak and asymmetric resonance corresponds to the broad transmission *** addition,a qualitative relation between the resonant energy separation Tr and group velocity vf is derived:Tr=πhvf n/L,that indicated Tr is proportional to vf and inversely proportional to the length L of the *** different Tr between the spin-up and spin-down cases results in the energyresolved spin filtering ***,the intensity of the circularly polarized light can modulate the group velocity ***,the intensity of circularly polarized light,as well as the conductor-length,play very vital roles in designing the energy-dependent spin *** the transmission gap root in the Fabry–Perot resonances,the thermoelectric(TE)property can be enhanced by adjusting the gap.A schedule to enhance the TE performance in the TI-junction is proposed by modulating the electric field(Ez).The TE dependence on Ez in the nanojunction is investigated,where the appropriate Ez leads to a very high spin thermopower and spin figure of *** TI junctions have potential usages in the nano spintronics and thermoelectric devices.

关键词： electron transport topological edge states 2D materials spintronics thermoelectric effects

ANALYSIS OF TWO-PHASE FLOW PrESSUrE BUILDUP DATA FrOM A WELL IN ANINFINITE MULTI WELL rESErVOIr

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Journal of Hydrodynamics 2005年第4期17卷 489-497页

作者： LIN Jia-en YANG Hui-zhu Department of engineering Mechanics Tsinghua University Beijing 100084 China Petroleum engineering Institute Xi＇an Petroleum University Xi＇an 710065China Department of engineering Mechanics Tsinghua UniversityBeijing 100084 China

A general method has been developed for analyzing two-phase flow pressure buildup data from a well located in a system of both production and injection wells completed in an infinite muhiwell reservoir. The analysis technique assumes that the tested well has established its own drainage area before shut-in and a linear reservoir pressure trend dominates the well pressure behavior at the instant of shut-in. And for the two-phase flow problems the horizontal saturation gradients are assumed to be negligible. The entire pressure rcsponse, whether or not conventional semilog straight lines exist, can be analyzed and the Injection-Production ratio （IPr）, the total fluid （oil/water） mobility, the average drainage-area pressure, and also the skin factor can be calculated much easily. The validity and applicability of the method are demonstrated by a field example. The technique by using the type curves for analyzing the pressure-buildup data is also presented here.

关键词： two-phase flow infinite multiwell reservoir well test analysis typc-curve analysis

Change Color Effect and Spectral Properties of Gold Nanoparticle-cationic Surfactants System

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Chemical research in Chinese Universities 2004年第5期20卷 523-528页

作者： JIANGZhi-liang PANHong-cheng YUANWei-en DepartmentofresourceandenvironmentalScience GuangxiNormalUniversityGuilin541004P.R.China

The change color effect of gold nanoparticle solutions was studied by means of resonance scattering and absorption spectrometry and scan electron microscopy. The red Au nanoparticles with a size of 10 nm exhibit a resonance absorption peak and a resonance scattering peak all at 525 nm. After some inorganic electrolyte was added to a red Au nanoparticles solution, the color of the solution became blue and the absorbance at (600_700) nm was significantly increased. The ratio of the concentration of monovalent cations, at which the resonance scattering of the system at 525 nm is maximal to that of divalent cations, is in the range of 100∶1_100∶1.8. It is in good agreement with the Schulze-Hardy rule of the coagulation value of electrolyte. After adding some cationic surfactants to the above solution, the color of the solution is in deep blue, with two resonance absorption peaks at 550 and 680 nm, and a greatly enhanced resonance scattering peak at 525 nm. The experiments demonstrate that the stronger the hydrophobicity of the cationic surfactant is, the stronger the change color effect of the Au nanoparticle solution promoted by cationic surfactant is. The change color effect of Au nanoparticle solution is resulted from the increased diameter of Au nanoparticles, and the changes of resonance absorption peak and resonance scattering.

关键词： Change color effect Gold nanoparticle Cationic Surfactant

Precipitated phases of superaustenitic stainless steel 654SMO

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Journal of Iron and Steel research International 2017年第7期24卷 743-749页

作者： Zhi-gang Song en-xiang Pu Special Steel Institute Central Iron & Steel Research Institute School of Materials Science and engineering Tsinghua University

The phase diagram of superaustenitic stainless steel 654SMO was calculated by thermodynamic software and the precipitated phases in the specimens aged at 800-1100°C for 1hwere studied by methods of physicochemical phase analysis,scanning electron microscopy and transmission electron *** results showed that the size of precipitated particles increased with increasing the *** amount of second phases reached the maximum value at 900°C,but decreased above 900°*** were about eight kinds of precipitated phases in 654SMO includingσphase,Cr_2N,μphase,χphase,Laves phase,M_（23）C_6,M_6C and M_3C,in which theσphase and Cr_2N were the dominant precipitated phases.

关键词： 654SMO Precipitation Superaustenitic stainless steel Precipitated phase Second phase

Novel developments in computational spectropolarimeter

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Light(Science & Applications) 2023年第3期12卷 321-322页

作者： en-Lin Hsiang Shin-Tson Wu College of Optics and Photonics University of Central FloridaOrlandoFL 32816USA

Compared to conventional bulky spectropolarimeters,computational spectropolarimeters which reconstruct light-field information such as polarization and spectrum in a compact form factor,are critical equipment enabling new *** key component of a computational spectropolarimeter is a tunable light-field modulator,in which liquid crystal-based device is a promising *** varying the applied voltage,the tunable liquid crystal metasurface can modulate the phase and spectral information of the incident light,and after a few trials,this important information can be decoded *** a novel approach paves the foundation for developing compact and low-cost spectropolarimetric imaging devices with widespread applications in biomedical imaging,remote sensing,and optical communications.

关键词： tunable polarization modulator