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Improved Methods for In-situ Measurement Railway Noise Barrier Insertion Loss

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第1期35卷 58-68页

作者： Li Qiutong Duhamel denis Luo Yanyun Yin Honoré Université Paris-Est Laboratoire NavierENPC-IFSTTAR-CNRS Institute of Railway Transit Tongji University

Many countries which seek to understand the acoustic performance of railway noise barriers have established standards for the conduct of in-situ ***,there are no universally acknowledged receiver positions for the evaluation of the barrier performance,a fact which may be leading to uncertainty over the noise reduction capabilities of available *** terms of the descriptor of the barrier performance,the general recommendation is the A-weighted sound pressure level,although the latter is considered to underestimate low frequencies for railway noise ***,in this study,the comparison of receiver positions and the descriptors among existing Chinese,ISO and European standards were *** upon a combination of diffraction theory and standards,a rearrangement of receiver positions and one-third-octave-band analysis were *** addition,in line with improved methods,an in-situ measurement of insertion loss for a 1.5 mhigh railway noise barrier was designed and *** results of the experiment validate as effective and applicable the new receiver *** results also suggest that one-third-octave-band analysis is indispensable.

关键词： railway noise noise barrier in-situ experiment A-weighting insertion loss one-third-octave-band analysis grid receiver positions

Advances in quantum dots for classical and non-classical light sources Invited Paper

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Chinese Optics Letters 2008年第10期6卷 718-723页

作者： Yasuhiko Arakawa Satoshi Iwamoto Satoshi Kako Masahiro Nomura denis Guimard Research Center for Advanced Science and Technology Institute for Nano Quantum Information ElectronicsThe University of Tokyo4-6-1 Meguro-ku153-8505 TokyoJapan

Recent advances in quantum dots （QDs） for classical and non-classical light sources are presented. We have established metal organic chemical vapor deposition （MOCVD） technology for InAs-based QD lasers at 1.3 μm and achieved ultralow threshold in QD lasers with photonic crystal （PhC） nanocavity. In addition, single photon emitters at 1.55 μm, GaN-based single photon sources operating at 200 K, and high-Q PhC nanocavity have been demonstrated.

关键词： QDs Advances in quantum dots for classical and non-classical light sources Invited Paper AIN InAs

Responses of jointed rock masses subjected to impact loading

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第4期10卷 624-634页

作者： Shabnam Aziznejad Kamran Esmaieli John Hadjigeorgiou denis Labrie Lassonde Institute of Mining University of Toronto CanmetMINING Natural Resources Canada

Impact-induced damage to jointed rock masses has important consequences in various mining and civil engineering applications. This paper reports a numerical investigation to address the responses of jointed rock masses subjected to impact loading. It also focuses on the static and dynamic properties of an intact rock derived from a series of laboratory tests on meta-sandstone samples from a quarry in Nova Scotia, Canada. A distinct element code(PFC2D) was used to generate a bonded particle model(BPM) to simulate both the static and dynamic properties of the intact rock. The calibrated BPM was then used to construct large-scale jointed rock mass samples by incorporating discrete joint networks of multiple joint intensities into the intact rock matrix represented by the BPM. Finally, the impact-induced damage inflicted by a rigid projectile particle on the jointed rock mass samples was determined through the use of the numerical model. The simulation results show that joints play an important role in the impactinduced rock mass damage where higher joint intensity results in more damage to the rock mass. This is mainly attributed to variations of stress wave propagation in jointed rock masses as compared to intact rock devoid of joints.

关键词： Jointed rock mass Impact loading Microcracks Rock damage

Pseudo-static stability analysis of rock slopes reinforced by passive bolts using the generalized Hoek-Brown criterion

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第4期9卷 659-670页

作者： Mounir Belghali Zied Saada denis Garnier Samir Maghous Laboratoire de Génie Civil ENIT Université de Tunis El Manar Tunis Tunisia Université Paris-Est Laboratoire Navier (UMR8205) ENPC-IFSTTAR-CNRS Marne-la-Vallée France Department of Civil Engineering Federal University of Rio Grande do Sul Av. Osvaldo Aranha 99 Porto Alegre RS 90350-190 Brazil

The stability analysis of passive bolt-reinforced rock slopes under seismic loads is investigated within the framework of the kinematic approach of limit analysis theory.A pseudo-static method is adopted to account for the inertial forces induced in the rock mass by seismic *** strength properties of the rock material are described by a modified Hoek-Brown strength criterion,whereas the passive bolts are modeled as bar-like inclusions that exhibit only resistance to tensile-compressive *** advantage of the ability to compute closed-form expressions for the support functions associated with the modified Hoek-Brown strength criterion,a rotational failure mechanism is implemented to derive rigorous lower bound estimates for the amount of reinforcement strength to prevent slope *** approach is then applied to investigating the effects of relevant geometry,strength and loading parameters in light of a preliminary parametric *** accuracy of the approach is assessed by comparison of the lower bound estimates with finite element limit analysis solutions,thus emphasizing the ability of the approach to properly predict the stability conditions and to capture the essential features of deformation localization ***,the extension of the approach to account for slipping at the interface between reinforcements and surrounding rock mass is outlined.

关键词： Reinforced rock slope Modified Hoek-Brown criterion Seismic loading Limit analysis Rotational failure mechanism

Spatial distribution of Vespa velutina individuals hunting at domestic honeybee hives： heterogeneity at a local scale

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Insect Science 2014年第6期21卷 765-774页

作者： Karine Monceau Olivier Bonnard Jerome Moreau denis Thiery INRA UMR1065 Sante et Agroecologie du Vignoble F-33883 Villenave d'Omon ISVV UMR1065 Sante et Agroecologie du Vignoble Bordeaux Sciences Agro Universite de Bordeaux F-33883 Villenave d'Omon Equipe Ecologie Evolutive UMR 6282 Biogeosciences 6 Bd Gabriel Universite de Bourgogne F-21000 Dijon France

Since its recent introduction into Europe, the yellow-legged hornet, Vespa velutina, has become a major predator of the domestic honeybee, Apis mellifera, but little is known about its hunting behavior. We studied V. velutina hunting behavior by a capture- mark-recapture procedure in an experimental apiary. A total of 360 hornets were captured and tagged, and we determined：（i） the number of hornets visiting the apiary and the changes in time, （ii） the average number of individual visits per half-day and the time elapsed between consecutive recaptures, and （iii） the individual and global distribution of the hornets in the apiary. More than 50% of the marked hornets were recaptured at least once, this increased to 74% in considering the first marked individuals. We estimated 350 hornets visiting the patch daily with at least 1 visit per half-day. The number of marked hornets decreased over time while the number of unmarked ones increased, suggesting a turnover of individuals. The reduction of the delay between consecutive visits indicates that hornets became more efficient over time. Most of the hornets （88%） were recaptured in front of different hives but, overall, the global distribution was aggregative. Hornets were mainly recaptured in front of 1 hive which was neither the smallest nor the biggest colony, suggesting that the major cue used by hornets is not the amount of food. We hypothesize that the defensive behavior of the honeybee colony could explain our results which may be promising to further studies.

关键词： Apis mellifera capture-mark-recapture learning predation Vespidae yellow-legged hornet

Plasma-enabled healing of graphene nano-platelets layer

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Frontiers of Chemical Science and Engineering 2019年第2期13卷 350-359页

作者： Xiuqi Fang Carles Corbella denis B.Zolotukhin Michael Keidar Department of Mechanical & Aerospace Engineering George Washington UniversityWashingtonDC 20052USA Department of Physics Tomsk State University of Control Systems and RadioelectronicsTomsk 634050Russia

Graphene platelet networks (GPNs) were deposited onto silicon substrates by means of anodic arc discharge ignited between two graphite *** temperature and pressure of helium atmosphere were optimized for the production of the carbon *** samples were modified or destroyed with different methods to mimic typical environments responsible of severe surface *** emulated conditions were performed by four surface treatments,namely thermal oxidation,substrate overheating,exposition to glow discharge,and metal coating due to arc *** the next step,the samples were regenerated on the same substrates with identical deposition *** and re-growth of GPN samples were systematically characterized by scanning electron microscopy and Raman *** full regeneration of the structural and morphological properties of the samples has proven that this healing method by arc plasma is adequate for restoring the functionality of2D nanostructures exposed to harsh environments.

关键词： graphene platelet networks anodic arc discharge plasma healing scanning electron microscopy Raman spectroscopy

Measurement of electrical charges carried by airborne bacteria laboratory-generated using a single-pass bubbling aerosolizer

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Particuology 2015年第1期13卷 179-185页

作者： Xavier Simon Sébastien Bau denis Bémer Philippe Duquenne Institut National de Recherche et de Securite(INRS)

Widely used bioaerosol generators like Collison nebulizer probably produce electrostatically charged par- ticles, but the electrical charges carried by laboratory-generated airborne microorganisms using bubbling aerosolizers are poorly understood. In this study, we measured the fraction of neutral particles and num- ber of elementary charges per particle as a function of the aerodynamic diameter of airborne bacteria （Escherichia coli and Enterococcus hirae）. Bioaerosols were produced by a liquid sparging aerosolizer-type bubbling generator, with particle sizes ranging from roughly 0.6 to 2 p^m. The experimental setup included an electrostatic precipitator and real-time devices including an electrometer, aerodynamic particle sizer, and electrical low-pressure impactor. Experimental results obtained for various operating conditions showed that aerosols produced with a higher bubbling airflow contained a larger proportion of neutral particles （from around 30% to 50%） and that bacteria carried a greater average absolute number of elementary charges （from around -10 to -60 elementary units） than those under lower airflow. Under the investigated conditions, a neutralization step is unnecessary because it may have a negative effect on the viability of sensitive microorganisms. Our results suggest that the neutral fraction can be used down- stream of an electrostatic precipitator, and that this setup may have advantages over bipolar neutralizers.

关键词： Bubbling generator Bioaerosol Electrical charge Electrostatic precipitator Escherichia coil Enterococcus hirae

Free tissue transfer for lower extremity trauma in the pediatric patient

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Plastic and Aesthetic Research 2022年第1期9卷 529-538页

作者： Sammy Othman denis Knobel Division of Plastic and Reconstructive Surgery Department of SurgeryNorthwell HealthNew YorkNY 11021USA

Aim:The utilization of free-tissue transfer secondary to traumatic lower extremity defects in the pediatric population is scarcely *** include microsurgeon inexperience,inadequate center resources,and fear of historically described poor surgical *** aim of this study is to investigate more recent articles describing free-flap microsurgical reconstruction for these ***:A systematic review of the literature was conducted through the online databases PubMed,Embase,and Web of Science,examining for articles with at least 20 subjects utilizing free-tissue transfer for soft-tissue defects of the pediatric(aged 18 and younger)lower extremity following traumatic etiology since *** included flap failure,return to the operating room,and functional status,where ***:Seven studies were deemed appropriate for inclusion,with a total of 243 flaps *** vehicle and motorcycle accidents were greater than 75%of total *** defects involved the foot or ankle(65.1%).In total,perforator flaps compromised the majority of flaps(54%),with the most common being the anterolateral thigh,the scapular/parascapular,and deep inferior epigastric *** common perforators included the groin flap,tensor fascia lata,radial forearm,lateral arm,and thoracodorsal perforator ***-based flaps were less common(46%),with the latissimus dorsi and rectus muscle flaps composing the *** most commonly used recipient vessel was the anterior tibialis(49.5%)and posterior tibialis vessels(45.3%).Most studies performed reconstruction within 7-10 days of *** was a cumulative 6.5%flap failure ***:Free tissue transfer for pediatric lower extremity trauma is an important tool that likely leads to powerful *** trends indicate increasing usage of perforator *** study shows that based on existing data,free flap utilization for pediatric patients is an adequate modality for repair,and ma

关键词： Reconstructive surgery pediatric trauma pediatric lower extremity microsurgery soft-tissue freetissue transfer

Enhanced efficiency and stability of 3.3 V Cu-Li batteries by tuning the cation-anion interaction in the electrolyte

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Journal of Energy Chemistry 2023年第11期86卷 208-216,I0005页

作者： Kaiming Xue Yu Zhao Huimin Wang denis Y.W.Yu School of Energy and Environment City University of Hong KongKowloonHong Kong 999077China Research Center for Energy and Environmental Materials(GREEN) National Institute for Materials ScienceTsukubaIbaraki 305-0044Japan

Cu-Li battery with Cu metal cathode and Li metal anode is a candidate for next-generation energy storage *** self-discharge of the battery can be suppressed with an anion exchange membrane,the voltage polarization depends strongly on the ***,when an electrolyte with 3 M LiTFSI(lithium bis(trifluoromethanesulfonyl)imide)in dimethyl carbonate(DMC)is used,overpotential increases with *** this work,we reveal why the voltage polarization changes,and reduce and stabilize it by replacing DMC solvent with a mixed solvent composed of dimethoxyethane(DME)and propylene carbonate(PC).The new electrolyte has higher ionic conductivity and stable solvation structure with more free TFSI-anions upon cycling,which also facilitates uniform plating of metal ions on the metal *** characteristics enable a stable Cu-Li battery with minimal change in overpotential for more than 1500 cycles at a current density of 2 m A cm^(-2).

关键词： Cu-Li battery Metal cathode Electrolyte engineering Solvation structure