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Silicene nanoribbons on transition metal dichalcogenide substrates： Effects on electronic structure and ballistic transport

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Nano Research 2016年第11期9卷 3394-3406页

作者： Bas van den Broek Michel Houssa Augustin Lu Geoffrey Pourtois Valery Afanas'ev andre stesmans Semiconductor Physics Laboratory Department of Physics and Astronomy University of Leuven Celestijnenlaan 200 D B-3001 Leuven Belgium imec 75 Kapeldreef B-3001 Leuven Belgium Department of Chemistry Plasmant Research Group University of Antwerp B-2610 Wilrijk-Antwerp Belgium

The idea of stacking multiple monolayers of different two-dimensional materials has become a global pursuit. In this work a silicene armchair nanoribbon of width W and van der Waals-bonded to different transition-metal dichalcogenide （TMD） bilayer substrates MoX2 and WX2, where X = S, Se, Te is considered. The orbital resolved electronic structure and ballistic transport properties of these systems are simulated by employing van der Waals-corrected density functional theory and nonequilibrium Green＇s functions. We find that the lattice mismatch with the underlying substrate determines the electronic structure, correlated with the silicene buckling distortion and ultimately with the contact resistance of the two-terminal system. The smallest lattice mismatch, obtained with the MoTe2 substrate, results in the silicene ribbon properties coming close to those of a freestanding one. With the TMD bilayer acting as a dielectric layer, the electronic structure is tunable from a direct to an indirect semiconducting layer, and subsequently to a metallic electronic dispersion layer, with a moderate applied perpendicular electric field.

关键词： silicene transition metal dichalcogenides van der Waals heterostructure electronic structure ballistic transport

Topological to trivial insulating phase transition in stanene

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Nano Research 2016年第3期9卷 774-778页

作者： Michel Houssa Bas van den Broek Konstantina Iordanidou Anh Khoa Augustin Lu Geoffrey Pourtois Jean-Pierre Locquet Valery Afanas'ev andre stesmans Department of Physics and Astronomy University of Leuven Celestijnenlaan 200D B-3001 Leuven Belgium imec 75 Kapeldreef B-3001 Leuven Belgium

Electronic properties of stanene, the Sn counterpart of graphene are theoretically studied using first-principles simulations. The topological to trivial insulating phase transition induced by an out-of-plane electric field or by quantum confinement effects is predicted. The results highlight the potential to use stanene nanoribbons in gate-voltage controlled dissipationless spin-based devices and are used to set the minimal nanoribbon width for such devices, which is typically approximately 5 nm.

关键词： two-dimensional (2D)materials topological insulators density functional theory(DFT) simulations electronic structure

Distant cousins come to ABP1’s rescue

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Science China(Life Sciences) 2024年第1期67卷 219-220页

作者： andre Kuhn Dolf Weijers Laboratory of Biochemistry Wageningen UniversityStippeneng 46708WE Wageningenthe Netherlands

There are few plant processes that are not in one way or another influenced by the auxin signaling *** many roles auxin plays in plants have inspired a range of investigations towards understanding its mechanisms of *** recent years and decades,genetic analysis in the flowering plant Arabidopsis has been immensely successful in bringing a nuclear response mechanism to light(reviewed in Weijers and Wagner,2016).This system,the nuclear auxin pathway(NAP),acts by regulating gene expression,and when its components are mutated,growth and development is strongly disturbed(Weijers and Wagner,2016).

关键词： bringing disturbed Arabidopsis

Effect of thermo-mechanical conditions during constrained friction processing on the particle refinement of AM50 Mg-alloy phases

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JOURNAL OF MAGNESIUM AND ALLOYS 2024年第6期12卷 2298-2311页

作者： de Castro, Camila Caroline Neves, andre Martins Klusemann, Benjamin Helmholtz Zentrum Hereon Inst Mat & Proc Design Solid State Mat Proc D-21502 Geesthacht Germany Leuphana Univ Luneburg Inst Prod Technol & Syst D-21335 Luneburg Germany Helmholtz Zentrum Hereon Inst Hydrogen Technol Syst Design Mobil D-21502 Geesthacht Germany Helmut Schmidt Univ Univ German Fed Armed Forces Hamburg Dept Mech & Civil Engn D-22043 Hamburg Germany

Constrained Friction Processing (CFP) is a novel solid-state processing technique suitable for lightweight materials, such Mg- and Alalloys. The technique enables grain size refinement to fine or even ultrafine scale. In this study, the effect of CFP on the microstructural refinement of AM50 rods is investigated in terms of particle size and morphology of the eutectic and secondary phases originally present in the base material, in particular the eutectic /3-Mg 17 Al 12 and Al-Mn phases. For that purpose, as-cast and solution heat-treated base material and processed samples were analyzed. The Al 8 Mn 5 intermetallic phase was identified as the main secondary phase present in all samples before and after the processing. A notorious refinement of these particles was observed, starting from particles with an average equivalent length of a few micrometers to around 560 nm after the processing. The refinement of the secondary phase refinement is attributed to a mechanism analogous to the attrition comminution, where the combination of temperature increase and shearing of the material enables the continuous breaking of the brittle intermetallic particles into smaller pieces. As for the eutectic phase, the results indicate the presence of the partially divorced /3-Mg 17 Al 12 particles exclusively in the as-cast base material, indicating that no further phase transformations regarding the eutectic phase, such as dynamic precipitation, occurred after the CFP. In the case of the processed as-cast material analyzed after the CFP, the thermal energy generated during the processing led to temperature values above the solvus limit of the eutectic phase, which associated with the mechanical breakage of the particles, enabled the complete dissolution of this phase. Therefore, CFP was successfully demonstrated to promote an extensive microstructure refinement in multiple aspects, in terms of grain sizes of the alpha-Mg phase and presence and morphology of the Al-Mn and eutectic /3-

关键词： Constrained friction processing AM50 Refill friction stir spot welding Extrusion /3-Mg 17 Al 12 Al-Mn phases MAGNESIUM ALLOYS MICROSTRUCTURE EXTRUSION

Optimal Sizing and Power Losses Reduction of Photovoltaic Systems Using PVsyst Software

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Journal of Power and Energy Engineering 2024年第7期12卷 23-38页

作者： andre Boussaibo Armel Duvalier Pene Kitmo Institute of Technology University of Ngaoundere Ngaoundere Cameroon National Advanced School of Engineering of Maroua University of Maroua Maroua Cameroon

This paper presents a method for optimizing a grid-connected photovoltaic system through an LCL filter. An algorithm based on particle swarm optimization (PSO) is used to determine the number of batteries, the number of panels in series and in parallel, as well as to evaluate the joule losses due to cable heating and the switching losses of the multilevel inverters. This system is applied to a village named YAGOUA, located in the far north of Cameroon. The evaluation of the Joule effect and the switching losses as well as the regulation of the voltage level at the point of common coupling (PCC) are carried out in PVsyst and Matlab software, then at IEEE 33 bus. This algorithm reduced the Joule losses to 1.2% and the switching losses to 2.2%. A power of 210.4 MWh is produced, to be injected in the electrical network via an LCL filter. The THD calculation gave a rate of 3.015% in accordance with the 519 standards. Synchronization through the Phase Locked Loop (PLL) is performed. After the power was injected into the grid, the voltage and current remained in phase, showing the power factor correction and the efficiency of the filter. According to NASA meteorological data, the locality of YAGOUA gives the global solar irradiation forecast of 6.8 kW/m2.

关键词： Five Level Inverter LCL Filter MPPT Power Losses PVsyst

Remote estimates of suspended particulate matter in global lakes using machine learning models

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International Soil and Water Conservation Research 2024年第1期12卷 200-216页

作者： Zhidan Wen Qiang Wang Yue Ma Pierre andre Jacinthe Ge Liu Sijia Li Yingxin Shang Hui Tao Chong Fang Lili Lyu Baohua Zhang Kaishan Song Northeast Institute of Geography and Agroecology CASChangchunJilin130102China Department of Geology Indiana University∼Purdue UniversityIndianapolisIN44602USA University of Chinese Academy of Sciences Beijing100100China College of Geography and Urban Planning Liaocheng UniversityLiaochengChina

Suspended particulate matter(SPM)in lakes exerts strong impact on light propagation,aquatic ecosystem productivity,which co-varies with nutrients,heavy metal and micro-pollutant in *** lakes,SPM exerts strong absorption and backscattering,ultimately affects water leaving signals that can be detected by satellite *** regression models based on specific band or hand ratios have been widely used for SPM estimate in the past with moderate *** are still rooms for model accuracy improvements,and machine learning models may solve the non-linear relationships between spectral variable and SPM in *** assembled more than 16,400 in situ measured SPM in lakes from six continents(excluding the Antarctica continent),of which 9640 samples were matched with Landsat overpasses within±7 *** machine learning algorithms and two simple regression methods(linear and partial least squares models)were used to estimate SPM in lakes and the performance were *** overcome the problem of imbalance datasets in regression,a Synthetic Minority Over-Sampling technique for regression with Gaussian Noise(SMOGN)was adopted in this *** comparison,we found that gradient boosting decision tree(GBDT),random forest(RF),and extreme gradient boosting(XGBoost)models demonstrated good spatiotemporal transferability with SMOGN processed dataset,and has potential to map SPM at different year with good quality of Landsat land surface reflectance *** all the tested modeling approaches,the GBDT model has accurate calibration(n=6428,R^(2)=0.95,MAPE=29.8%)from SPM collected in 2235 lakes across the world,and the validation(n=3214,R^(2)=0.84,MAPE=38.8%)also exhibited stable ***,the good performances were also exhibited by RF model with calibration(R^(2)=0.93)and validation(R^(2)=0.86,MAPE=24.2%)*** applied GBDT and RF models to map SPM of typical lakes,and satisfactory result was *** addition,the GBDT model was evaluated b

关键词： Landsat imagery Remote estimation SPM Transferability

Re-evaluation of recent research on metabolic utilization of energy in poultry: Recommendations for a net energy system for broilers

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Animal Nutrition 2024年第1期16卷 62-72页

作者： Jean Noblet Aye-Cho Tay-Zar Shu-Biao Wu Pairat Srichana Pierre Cozannet Pierre-andre Geraert Mingan Choct INRAE Charoen Pokphand Foods Public Company Limited (CPF) School of Environmental and Rural Science University of New England Adisseo France S.A.S.

Different energy systems have been proposed for energy evaluation of feeds for domestic animals. The oldest and most commonly used systems take into account the fecal energy loss to obtain digestible energy(DE), and fecal, urinary and fermentation gases energy losses to calculate metabolizable energy(ME). In the case of ruminants and pigs, the net energy(NE) system, which takes into account the heat increment associated with the metabolic utilization of ME, has progressively replaced the DE and ME systems over the last 50 years. For poultry, apparent ME(AME) is used exclusively and NE is not yet used widely. The present paper considers some important methodological points for measuring NE in poultry feeds and summarizes the available knowledge on NE systems for poultry. NE prediction equations based on a common analysis of three recent studies representing a total of 50 complete and balanced diets fed to broilers are proposed; these equations including the AME content and easily available chemical indicators have been validated on another set of 30 diets. The equations are applicable to both ingredients and complete diets. They rely primarily on an accurate and reliable AME value which then represents the first limiting predictor of NE value. Our analysis indicates that NE would be a better predictor of broiler performance than AME and that the hierarchy between feeds is dependent on the energy system with a higher energy value for fat and a lower energy value for protein in an NE system. Practical considerations for implementing such an NE system from the commonly used AME or AMEn(AME adjusted for zero nitrogen balance) systems are presented. In conclusion, there is sufficient information to allow the implementation of the NE concept in order to improve the accuracy of feed formulation in poultry.

关键词： Poultry Feed evaluation Net energy Energy system

Uncovering the dominant contribution of intermediate volatility compounds in secondary organic aerosol formation from biomass-burning emissions

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National Science Review 2024年第3期11卷 150-158页

作者： Kun Li Jun Zhang David M.Bell Tiantian Wang Houssni Lamkaddam Tianqu Cui Lu Qi Mihnea Surdu Dongyu Wang Lin Du Imad El Haddad Jay G.Slowik andre S.H.Prevot Environment Research Institute Shandong University Laboratory of Atmospheric Chemistry Paul Scherrer Institute

Organic vapors from biomass burning are a major source of secondary organic aerosols(SOAs). Previous smog chamber studies found that the SOA contributors in biomass-burning emissions are mainly volatile organic compounds(VOCs). While intermediate volatility organic compounds(IVOCs) are efficient SOA precursors and contribute a considerable fraction of biomass-burning emissions, their contribution to SOA formation has not been directly observed. Here, by deploying a newly-developed oxidation flow reactor to study SOA formation from wood burning, we find that IVOCs can contribute ～70% of the formed SOA, i.e.>2 times more than VOCs. This previously missing SOA fraction is interpreted to be due to the high wall losses of semi-volatile oxidation products of IVOCs in smog chambers. The finding in this study reveals that SOA production from biomass burning is much higher than previously thought, and highlights the urgent need for more research on the IVOCs from biomass burning and potentially other emission sources.

关键词： atmospheric chemistry biomass burning secondary organic aerosol intermediate volatility organic compounds

Possible Uses for Silymarin in Human Health: Systematic Review

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American Journal of Plant Sciences 2024年第2期15卷 95-109页

作者： Gisele Mara Silva Gonçalves andre Bernardo de Camargo Eisingher Postgraduate Program in Health Sciences Pontifical Catholic University of Campinas (PUC-Campinas) Campinas Brazil

Silymarin, from the fruit of Silybum marianum, is known for its hepatoprotective action. The aim of this study was to review the mechanisms of action of the silymarin phytocomplex to expand the possibilities for its application in human health. The search for published articles was carried out on the CAPES Journals Portal platform, which covers worldwide scientific databases. Publications from 2010 to 2022 were included. Of the 311 articles retrieved, 21 were included. The articles discuss the diversity of silymarin’s applications and the possibility of optimizing its bioavailability using drug delivery systems. Silymarin shows promise in numerous diseases, such as liver, kidney, cardiovascular, respiratory and others. Its antiviral action has been demonstrated in studies and silymarin has the potential to be used as a complementary therapy in the treatment of many diseases, with the expectation that, in the future, it will be used in therapeutic protocols for exclusive use.

关键词： Silymarin Flavonoids Phytotherapeutic Drugs