142 research outputs found
Mechanism Design for Efficient Nash Equilibrium in Oligopolistic Markets
This paper investigates the efficiency loss in social cost caused by strategic bidding behavior of individual participants in a supply-demand balancing market, and proposes a mechanism to fully recover equilibrium social optimum via subsidization and taxation. We characterize the competition among supply-side firms to meet given inelastic demand, with linear supply function bidding and the proposed efficiency recovery mechanism. We show that the Nash equilibrium of such a game exists under mild conditions, and more importantly, it achieves the underlying efficient supply dispatch and the market clearing price that reflects the truthful system marginal production cost. Further, the mechanism can be tuned to guarantee self-sufficiency, i.e., taxes collected counterbalance subsidies needed. Extensive numerical case studies are run to validate the equilibrium analysis, and we employ individual net profit and a modified version of Lerner index as two metrics to evaluate the impact of the mechanism on market outcomes by varying its tuning parameter and firm heterogeneity
PtCo/MWCNTs Prepared By A Microwave-assisted Polyol Method For Selective Cinnamaldehyde Hydrogenation
Using microwave irradiation, PtCo alloy nanoparticles were deposited within a few minutes on COOH-functionalized MWCNT supports. The obtained catalysts were used for selective hydrogenation of cinnamaldehyde, a reaction whose products are widely used in various fields. In the selective cinnamaldehyde hydrogenation to cinnamyl alcohol, microwave-prepared catalysts (generically, PtxCoy-MW) outperformed a catalyst prepared by the conventional method (Pt1Co2-con). The highest selective hydrogenation to cinnamyl alcohol, 89%, was obtained using Pt1Co2-MW, while Pt1Co2-con showed a selectivity of 76%. Characterization results confirmed that the microwave prepared samples had a stronger interaction between Pt and Co than that in the Pt1Co2-con sample. The alloyed Co altered the electronic structure of Pt, leading to favorable adsorption of the C=O bond by the lone-pair electrons of its oxygen atom. Moreover, the Pt1Co2-MW sample showed neglectable change in catalytic performance (e. g., cinnamaldehyde conversion and selective hydrogenation to cinnamyl alcohol) during recycling experiments
Engineering Oxygen Vacancy-Rich CeOx overcoating Onto Ni/Al2O3 by Atomic Layer Deposition for Bi-Reforming of Methane
Atomic Layer Deposition (ALD) Was Applied to Develop CeOx-Overcoated Ni/Al2O3 Catalyst for Bi-Reforming of Methane (BRM), as the Combination of Dry Reforming of Methane (DRM) and Steam Reforming of Methane (SRM). Non-Stoichiometric CeOx Thin Films Were Successfully Deposited on Ni/Al2O3 Particles by ALD, Which Constructed a Beneficial Ni-CeOx Interface and Modified the Catalyst Property. Ascribed to the Unique ALD Growth Mode, a High Amount of Ce(III) and Oxygen Vacancies Existed in the ALD-Deposited CeOx overcoating. a Reduction Process Before the BRM Reaction Contributed to the Further Reduction of Ce(IV) to Ce(III), Resulting in More Oxygen Vacancies. the Oxygen Vacancies at the Ni-CeOx Interface Enabled a High Rate of CO2 Activation and Enabled the Balance between the Activation of CO2 and H2O for BRM. Due to its Oxygen Vacancies as Activation Sites for CO2 and H2O, CeOx ALD overcoating Significantly Improved the Activity of Ni/Al2O3 Catalyst and Achieved a Better Control in the H2/CO Ratio with a Suitable Ratio of H2O/CO2/CH4 Feed. CeOx overcoatings Enhanced the Reducibility of Ni(II) Sites and Assisted in Preventing Ni from Oxidation during the BRM Reaction. Less Carbon Deposition Was Achieved by the Ni/Al2O3 Catalyst with CeOx overcoating as Ascribed to its Better Reactant Activation Capacity
СОВРЕМЕННОЕ НАПРЯЖЕННОЕ СОСТОЯНИЕ ТЕКТОНИЧЕСКОГО ПОЯСА ШАНЬСИ
The Shanxi tectonic belt is a historically earthquakeabundant area. For the majority of strong earthquakes in this area, the distribution of earthquake foci was controlled by the N–S oriented local structures on the tectonic belt. Studies of the present stress state of the Shanxi tectonic belt can contribute to the understanding of the relationship between strong earthquakes’ occurrence and their structural distribution and also facilitate assessments of regional seismic danger and determination of the regions wherein strong earthquakes may occur in future. Using the Cataclastic Analysis Method (CAM), we performed stress inversion based on the focal mechanism data of earthquakes which took place in the Shanxi tectonic belt from 1967 to 2010. Our results show that orientations of the maximum principal compressive stress axis of the Shanxi tectonic belt might have been variable before and after the 2001 Kunlun MS=8.1 strong earthquake, with two different superior trends of the NW–SE and NE–SW orientation in different periods. When the maximum principal compressive stress axis is oriented in the NE–SW direction, the pattern of the space distribution of the seismic events in the Shanxi tectonic belt shows a trend of their concentration in the N–S oriented tectonic segments. At the same time, the stress state is registered as horizontal shearing and horizontal extension in the N–S and NE–SW oriented local segments in turn. When the maximum principal compressive stress axis is NW–SE oriented, the stress state of the N–S and NE–SW oriented tectonic segments is primarily registered as horizontal shearing. Estimations of plunges of stress axes show that seismicity in the Shanxi belt corresponds primarily to the activity of lowangle faults, and highangle stress sites are located in the NE–SW oriented extensional tectonic segments of the Shanxi belt. This indicates that the stress change of the Shanxi belt is caused by adjustment of the regional stress field, rather than by the diverse seismic activities.Согласно историческим данным, тектонический пояс Шаньси выделяется как зона с многочисленными землетрясениями. В большинстве случаев распределение эпицентров землетрясений контролируется локальными меридиональными структурами, входящими в состав данного тектонического пояса. Изучение современного напряженного состояния тектонического пояса Шаньси вносит вклад в понимание взаимоотношений между проявлением сильных землетрясений и их структурным распределением, а также содействует оценке региональной сейсмической опасности и выделению регионов, где в будущем возможны сильные землетрясения. С применением метода катакластического анализа (Cataclastic Analysis Method, CAM) проведена реконструкция напряженного состояния на базе данных о механизмах очагов землетрясений, зарегистрированных в тектоническом поясе Шаньси с 1967 г. по 2010 г. Результаты исследования показали, что ориентации осей максимальных главных напряжений сжатия в тектоническом поясе Шаньси, возможно, подвергались изменениям как до, так и после сильного Куньлунского землетрясения (MS=8.1), произошедшего в 2001 г., при этом в разные временные периоды выделены два разных тренда – северо-западной и северо-восточной ориентации. При ориентации оси максимального главного напряжения сжатия в северо-восточном направлении на схеме пространственного распределения сейсмических событий в тектоническом поясе Шаньси видна тенденция концентрации землетрясений в тектонических сегментах, ориентированных в меридиональном направлении. При этом зарегистрированное напряженное состояние характеризуется горизонтальным сдвигом и горизонтальным растяжением локальных сегментов, ориентированных в меридиональном и северо-восточном направлении. При ориентации оси максимального главного напряжения сжатия в северо-западном направлении напряженное состояние на тектонических сегментах, ориентированных в меридиональном и северо-восточном направлении, в основном определяется как горизонтальный сдвиг. Оценка углов погружения осей напряжений показывает, что сейсмичность тектонического пояса Шаньси коррелирует главным образом с активностью пологих разломов, при этом участки разломов с большими углами наклонов осей напряжений располагаются в северо-восточных тектонических сегментах пояса, подверженных растяжению. Результаты исследований показывают, что современное напряженное состояние тектонического пояса Шаньси изменяется в связи с вариациями регионального поля напряжений
BEV-LaneDet: a Simple and Effective 3D Lane Detection Baseline
3D lane detection which plays a crucial role in vehicle routing, has recently
been a rapidly developing topic in autonomous driving. Previous works struggle
with practicality due to their complicated spatial transformations and
inflexible representations of 3D lanes. Faced with the issues, our work
proposes an efficient and robust monocular 3D lane detection called BEV-LaneDet
with three main contributions. First, we introduce the Virtual Camera that
unifies the in/extrinsic parameters of cameras mounted on different vehicles to
guarantee the consistency of the spatial relationship among cameras. It can
effectively promote the learning procedure due to the unified visual space. We
secondly propose a simple but efficient 3D lane representation called
Key-Points Representation. This module is more suitable to represent the
complicated and diverse 3D lane structures. At last, we present a light-weight
and chip-friendly spatial transformation module named Spatial Transformation
Pyramid to transform multiscale front-view features into BEV features.
Experimental results demonstrate that our work outperforms the state-of-the-art
approaches in terms of F-Score, being 10.6% higher on the OpenLane dataset and
5.9% higher on the Apollo 3D synthetic dataset, with a speed of 185 FPS. The
source code will released at https://github.com/gigo-team/bev_lane_det.Comment: Accepted by CVPR202
Effect of Fans’ Placement on the Indoor Thermal Environment of Typical Tunnel-Ventilated Multi-Floor Pig Buildings Using Numerical Simulation
An increasing number of large pig farms are being built in multi-floor pig buildings (MFPBs) in China. Currently, the ventilation system of MFPB varies greatly and lacks common standards. This work aims to compare the ventilation performance of three popular MFPB types with different placement of fans using the Computational Fluid Dynamics (CFD) technique. After being validated with field-measured data, the CFD models were extended to simulate the air velocity, air temperature, humidity, and effective temperature of the three MFPBs. The simulation results showed that the ventilation rate of the building with outflowing openings in the endwall and fans installed on the top of the shaft was approximately 25% less than the two buildings with fans installed on each floor. The ventilation rate of each floor increased from the first to the top floor for both buildings with a shaft, while no significant difference was observed in the building without a shaft. Increasing the shaft’s width could mitigate the variation in the ventilation rate of each floor. The effective temperature distribution at the animal level was consistent with the air velocity distribution. Therefore, in terms of the indoor environmental condition, the fans were recommended to be installed separately on each floor
Effects of Film Thickness of ALD-Deposited Al2O3, ZrO2 and HfO2 Nano-Layers on the Corrosion Resistance of Ti(N,O)-Coated Stainless Steel
The goal of this stydy was to explore the potential of the enhanced corrosion resistance of
Ti(N,O) cathodic arc evaporation-coated 304L stainless steel using oxide nano-layers deposited by
atomic layer deposition (ALD). In this study, we deposited Al2O3, ZrO2, and HfO2 nanolayers of
two different thicknesses by ALD onto Ti(N,O)-coated 304L stainless steel surfaces. XRD, EDS, SEM,
surface profilometry, and voltammetry investigations of the anticorrosion properties of the coated
samples are reported. The amorphous oxide nanolayers homogeneously deposited on the sample
surfaces exhibited lower roughness after corrosion attack compared to the Ti(N,O)-coated stainless
steel. The best corrosion resistance was obtained for the thickest oxide layers. All samples coated
with thicker oxide nanolayers augmented the corrosion resistance of the Ti(N,O)-coated stainless
steel in a saline, acidic, and oxidising environment (0.9% NaCl + 6% H2O2, pH = 4), which is of
interest for building corrosion-resistant housings for advanced oxidation systems such as cavitation
and plasma-related electrochemical dielectric barrier discharge for breaking down persistent organic
pollutants in water
Charge Transport in Two-Photon Semiconducting Structures for Solar Fuels
Semiconducting heterostructures are emerging as promising light absorbers and offer effective electron–hole separation to drive solar chemistry. This technology relies on semiconductor composites or photoelectrodes that work in the presence of a redox mediator and that create cascade junctions to promote surface catalytic reactions. Rational tuning of their structures and compositions is crucial to fully exploit their functionality. In this review, we describe the possibilities of applying the two-photon concept to the field of solar fuels. A wide range of strategies including the indirect combination of two semiconductors by a redox couple, direct coupling of two semiconductors, multicomponent structures with a conductive mediator, related photoelectrodes, as well as two-photon cells are discussed for light energy harvesting and charge transport. Examples of charge extraction models from the literature are summarized to understand the mechanism of interfacial carrier dynamics and to rationalize experimental observations. We focus on a working principle of the constituent components and linking the photosynthetic activity with the proposed models. This work gives a new perspective on artificial photosynthesis by taking simultaneous advantages of photon absorption and charge transfer, outlining an encouraging roadmap towards solar fuels
LiveVV: Human-Centered Live Volumetric Video Streaming System
Volumetric video has emerged as a prominent medium within the realm of
eXtended Reality (XR) with the advancements in computer graphics and depth
capture hardware. Users can fully immersive themselves in volumetric video with
the ability to switch their viewport in six degree-of-freedom (DOF), including
three rotational dimensions (yaw, pitch, roll) and three translational
dimensions (X, Y, Z). Different from traditional 2D videos that are composed of
pixel matrices, volumetric videos employ point clouds, meshes, or voxels to
represent a volumetric scene, resulting in significantly larger data sizes.
While previous works have successfully achieved volumetric video streaming in
video-on-demand scenarios, the live streaming of volumetric video remains an
unresolved challenge due to the limited network bandwidth and stringent latency
constraints. In this paper, we for the first time propose a holistic live
volumetric video streaming system, LiveVV, which achieves multi-view capture,
scene segmentation \& reuse, adaptive transmission, and rendering. LiveVV
contains multiple lightweight volumetric video capture modules that are capable
of being deployed without prior preparation. To reduce bandwidth consumption,
LiveVV processes static and dynamic volumetric content separately by reusing
static data with low disparity and decimating data with low visual saliency.
Besides, to deal with network fluctuation, LiveVV integrates a volumetric video
adaptive bitrate streaming algorithm (VABR) to enable fluent playback with the
maximum quality of experience. Extensive real-world experiment shows that
LiveVV can achieve live volumetric video streaming at a frame rate of 24 fps
with a latency of less than 350ms
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