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Developing molecular-level models for organic field-effect transistors

National Science Review 2021年第4期8卷 167-180页

作者： Haoyuan Li Jean-Luc brédas School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics Georgia Institute of Technology Department of Chemistry and Biochemistry University of Arizona

Organic field-effect transistors(OFETs) are not only functional devices but also represent an important tool for measuring the charge-transport properties of organic semiconductors(OSs). Thus, efforts to understand the performance and characteristics of OFET devices are not only useful in helping achieve higher device efficiencies but also critical to ensuring accuracy in the evaluations of OS charge *** studies rely on OFET device models, which connect the measured current characteristics to the properties of the OSs. Developing such OFET models requires good knowledge of the charge-transport processes in OSs. In device active layers, the OS thin films are either amorphous(e.g. in organic light-emitting diodes and organic solar cells) or crystalline(e.g. those optimized for charge transport in OFETs). When the electronic couplings between adjacent OS molecules or polymer chain segments are weak, the charge-transport mechanism is dominated by hopping processes, which is the context in which we frame the discussion in this Review. Factors such as disorder, mobility anisotropy, traps, grain boundaries or film morphology all impact charge transport. To take these features fully into account in an OFET device model requires considering a nano-scale, molecular-level resolution. Here, we discuss the recent development of such molecular-resolution OFET models based on a kinetic Monte Carlo approach relevant to the hopping regime. We also briefly describe the applicability of these models to high-mobility OFETs,where we underline the need to extend them to incorporate aspects related to charge delocalization.

关键词： organic semiconductors charge transport kinetic Monte Carlo simulations mobility measurements gradual channel approximation

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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

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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

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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

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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

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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

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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

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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

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Biochar as adsorbent in purification of clear-cut forest runoff water:adsorption rate and adsorption capacity

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Biochar 2020年第2期2卷 227-237页

作者： Taija Saarela Elham Kakaei Lafdani Ari laur.n Jukka Pumpanen Marjo Palviainen Department of environmental and Biological Sciences University of Eastern FinlandYliopistonranta 1 EFI-70210 KuopioFinland School of Forest Sciences University of Eastern FinlandYliopistokatu 7FI-80101 JoensuuFinland Department of Forest Sciences University of HelsinkiLatokartanonkaari 7FI-00014 HelsinkiFinland

Forest management practices in boreal peatlands increase nutrient export and suspended solids to watercourses calling for development of new water protection *** potential solution could be adsorption-based purification of runoff water using *** aim of this study was to determine the adsorption rate and capacity for Norway spruce and silver birch biochars to design a biochar-filled reactor for a ditch *** a 10-day laboratory experiment,biochar was stirred with runoff water from a clear-cut peatland forest,and changes in water pH,total nitrogen,nitrate nitrogen,ammonium nitrogen,phosphorus,and total organic carbon concentrations were *** on the concentration changes,adsorption was quantified and adsorption model containing the adsorption rate and capacity was fitted to the *** results indicate that biochar effectively adsorbs both inorganic and organic nitrogen from runoff *** biochar had higher adsorption capacity of nitrogen than spruce *** study demonstrates that the adsorption of nitrogen compounds onto biochar surfaces increases with increasing initial ***,aquatic ecosystems exposed to high nutrient loads from fertile peatlands would particularly benefit from biochar-based water purification.

关键词： Adsorption Ammonium Biochar Nitrate Nutrients Total nitrogen Water quality

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Irradiation behaviors of two novel single-phase bcc-structure high-entropy alloys for accident-tolerant fuel cladding

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Journal of Materials Science & Technology 2021年第25期84卷 230-238页

作者： Zijian Zhang en-Hou Han Chao Xiang Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and engineering University of Science and Technology of ChinaShenyang110016China School of Materials Science and engineering Northeastern UniversityShenyang110819China

High-entropy alloys(HEAs)are potential alternative materials for accident-tolerant fuel cladding due to their excellent irradiation resistance and high-temperature corrosion *** this work,two novel body-centered cubic(bcc)structured Mo_(0.5)Nb Ti VCr_(0.25)and Mo_(0.5)Nb Ti V_(0.5)Zr_(0.25)HEAs were ***-ion irradiation was performed on the two HEAs to simulate neutron irradiation,and the crystal structure,hardness,and microstructure evolution were *** crystal structure of the Mo_(0.5)NbTiVCr_(0.25)HEA remained stable at low fluences,while amorphization may occur at high fluences in the two *** irradiation hardening value of the Mo_(0.5)NbTiVCr_(0.25)was 0.77 GPa at fluences of 1×10^(17)ions/cm^(2)and 1.49 GPa at fluences of 5×10^(17)ions/cm^(2),while the hardening value of the Mo_(0.5)NbTiV_(0.5)Zr_(0.25)was 1.36 GPa at ion fluences of 5×10^(17)ions/cm^(2).In comparison with most of the conventional alloys,the two HEAs showed slight irradiation *** helium bubbles and dislocation loops with small size were observed in the two HEAs after *** is the first time to report the formation of a dislocation loop in bcc-structure HEAs after ***,voids and precipitates were not observed in the two HEAs which could be ascribed to the high lattice distortion and compositional complexity of *** research revealed that the two HEAs show outstanding irradiation resistance,which may be promising accident-tolerant fuel cladding materials.

关键词： High-entropy alloy Accident-tolerant fuel cladding Helium-ion irradiation Microstructure Irradiation hardening

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