检索结果-内蒙古大学图书馆

Numerical Comparison of Transpiration Cooling designs Using Real Gas Effects and Approximate Gas Model

Journal of Physics: Conference Series 2021年第1期2097卷

作者： Meng Wang Jianhua Wang Fei He Kang Qian Yadong Wu Guangsheng Zhu CAS Key Laboratory of Mechanical Behaviour and Design of Materials Department of Thermal Science and Energy Engineering University of Science and Technology of China Hefei 230027 Anhui China Beijing Institute of Astronautical System Engineering Beijing 100076 China

In the severe high-temperature environment caused by aerodynamic heating, the vibrational excitation, dissociation and ionization of gas may successively occur, which are known as real gas effects. Under the real gas effects, the thermodynamic properties of gas vary drastically and significantly influence the performances of the active thermal protection system of hypersonic vehicles, especially in the case with coolant outflow, for example transpiration cooling. This paper numerically investigates the transpiration cooling performance with the consideration of the interaction between coolant outflow and hypersonic flow under the real gas effects. The mathematical models and coupled numerical strategy are firstly validated by experimental data, then the influences of real gas effects on the transpiration cooling of a wedged leading edge (WLE) are studied under a flight Mach number range from 8 to 12 and a flight height of 40 km. The analysis and discussions of the numerical results reveal some important phenomena and demonstrate the need to consider real gas effects.

关键词：

来源：评论

学校读者我要写书评

暂无评论

The Investigation of Removal and Mechanism by Different Permeable Paving systems on Runoff Pollutants

SSRN

引用

SSRN 2024年

作者： Zhang, Ziyang Yang, Ying Li, Zhifei Chen, Hongrui Zhang, Xiaoran Gong, Yongwei Tan, Chaohong Li, Haiyan Key Laboratory of Urban Stormwater System and Water Environment Ministry of Education Beijing University of Civil Engineering and Architecture Beijing102616 China Beijing Energy Conservation & Sustainable Urban and Rural Development Provincial Ministry Co-construction Collaboration Innovation Center Beijing100044 China Beijing General Municipal Engineering Design ＆ Research Institute Co. Ltd Beijing100082 China CRRC Environmental Science & Technology Cooperation Beijing100067 China Beijing Engineering Research Center of Sustainable Urban Sewage System Construction and Risk Control Beijing University of Civil Engineering and Architecture Beijing100044 China

In order to investigate the runoff pollutant control effects by different types of permeable paving systems (PPS), Porous asphalt (PA), Porous concrete (PC), Cement brick (CTB), Ceramic brick (CCB), Sand base brick (SBB) and Shale brick (SB) were selected. The removal effects and mechanisms of six PPS and individual filler layer on chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3-N), total nitrogen (TN) and total phosphorus (TP)were investigated. Studies have shown that the removal of runoff pollutants varies widely among different PPS. PA had the best removal effect for nearly all runoff pollutants, which the maximum removal rate was 100% for both COD and NH4+-N. Permeable bricks could effectively control on NO3-N and TN pollutants, which the best removal efficiency were more than 94% for SB. Compared with other runoff pollutants, PC was more effective in removing TP with a removal rate of 95.8%. Furthermore, compared with surface material, base layer, subbase layer and soil layer were the most effective in controlling pollution in runoff, which the removal rate were more than 80%. Due to the deeper length, pollutants in runoff could contact with filler longer time and increased the removal efficiency. At the same time, graded gravel and medium sand have a stronger adsorption capacity for pollutants in runoff, resulting in a better purification. This study provides theoretical and practical significance not only for runoff pollution control, but also for the design and use of PPS in runoff. © 2024, The Authors. All rights reserved.

关键词： Fillers

来源：评论

学校读者我要写书评

暂无评论

ADVANCES IN LONG-RANGE, HIGH-SPEED OPTICAL COMMUNICATION

引用

NAVAL ENGINEERS JOURNAL 1981年第4期93卷 39-48页

作者： BARTON, GG FELDMAN, S Mr. Sidney Feldman formerly with the Naval Applied Science Laboratory is presently with the Radiation Division of the Naval Surface Weapons Center White Oak Silver Spring Maryland. He planned and supervised laboratory experiments of many optical systems for fleet evaluation several of his designs now being standard in the fleet. He received his BA degree in Physics from Brooklyn College in 1941 and majored in Physics at the Brooklyn Polytechnic Institute. His professional memberships include the Optical Society of America American Association for the Advancement of Science and The Scientific Research Society of North America. He was the recipient of the Naval Ordnance Development Award in 1945 the Superior Achievement Award in 1957 the Quality Salary Increase Award in 1965 the Superior Accomplishment Award in 1967 1970 and 1979. Additionally he has been granted patents for a relamping tool for searchlights (1962) a lamp positioning mechanism for searchlights (1963) a daylnight digital sextant (1973) a portable sextant-computer system (1974) and with Mr. George Barton the remote-controlled LLLTV camera-sextant (1976) the automatic passive LLLTV-rangefinder (1977) and a patent disclosure for the omnidirectional transceiver (1980). Mr. George G. Barton has been employed by the Naval Research Laboratory Washington D. C. for the past ten years in the scientific and military application design engineering and fabrication of low light level TV camera systems. He was previously associated with the Smithsonian Institution and Northwestern University in the application of TV technology in astronomical investigations. He attended New York University Newark College of Engineering and New Mexico State University where he majored in Physical Optics. Presently he is with his own company BISMARC Inc. Harker's Island N.C. where he is involved principally in the design manufacture and marketing of sonar systems such as the unique VIDISEA fishscope research and development in electrooptic systems an

During periods of radio silence under Emission Control, communication depends on the slow ship-to-ship, manual-visual, 8-10 wpm Morse code signaling shutter searchlight employing the ac 1000-watt incandescent or the ac 1000-watt compact arc mercury-xenon lamp. These sources can be replaced by the dc compact arc xenon lamp to provide longer daylight ranges and highspeed (100 wpm teletype, 150 wpm Morse code, voice, etc.) communication since this source has superior brightness and the facility of considerably more rapid modulation. The excessive weight and size of the ac-dc power convertor and modulating circuitry which had prevented use of the dc xenon lamp have been overcome by developments in solid state electronics such as the rapid, high current, simmer-flash, 100 to one light output xenon lamp pulsing using the reliable, uncomplicated, low-cost silicon controlled rectifier shunt switch which could eliminate the mechanical signaling shutter. laboratory and sea evaluations have proved the feasibility of and provided the long daylight high-speed optical communication ranges that could be attained from operation of the dc 1000-watt and 2200-watt xenon lamps at the focus of 12-inch, 18-inch searchlights and in the Fresnel lens omni-directional beacon which a command ship uses to signal all ships in a task force at once. With these advances, optical communication provides the highspeed capability of radio communication, particularly, also, with the new omnidirectional transceiver.

关键词： SHIPS

来源：评论

学校读者我要写书评

暂无评论

ON THE SUPERSINGULAR LOCUS OF SHIMURA VARIETIES FOR QUATERNIONIC UNITARY GROUPS

arXiv

引用

arXiv 2023年

作者： Terakado, Yasuhiro Xue, Jiangwei Yu, Chia-Fu School of System Design and Technology Tokyo Denki University 5 Senju Asahi-cho Adachi-ku Tokyo120-8551 Japan Collaborative Innovation Center of Mathematics School of Mathematics and Statistics Wuhan University Luojiashan Hubei Wuhan430072 China Hubei Key Laboratory of Computational Science Wuhan University Hubei Wuhan430072 China Institute of Mathematics Academia Sinica Astronomy Mathematics Building No. 1 Sec. 4 Roosevelt Rd. Taipei106319 Taiwan

We study a Shimura variety attached to a unitary similitude group of a skew-Hermitian form over a totally indefinite quaternion algebra over a totally real number field. We give a necessary and sufficient condition for the existence of skew-Hermitian self-dual lattices. Under this condition we show that the superspecial locus in the fiber at p of the associated Shimura variety is non-empty. We also give an explicit formula for the number of irreducible components of the supersingular locus when p is odd and unramified in the quaternion algebra. Copyright © 2023, The Authors. All rights reserved.

关键词： Algebra

来源：评论

学校读者我要写书评

暂无评论

Secure ISAC MIMO systems: Exploiting Interference With Bayesian Cramér-Rao Bound Optimization

arXiv

引用

arXiv 2024年

作者： Su, Nanchi Liu, Fan Masouros, Christos Alexandropoulos, George C. Xiong, Yifeng Zhang, Qinyu Shenzhen518055 China The School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China The Department of Electronic and Electrical Engineering University College London LondonWC1E 7JE United Kingdom The Department of Informatics and Telecommunications National and Kapodistrian University of Athens Athens15784 Greece The School of Information and Electronic Engineering Beijing University of Posts and Telecommunications Beijing100876 China Shenzhen518055 China Peng Cheng Laboratory Shenzhen518055 China

In this paper, we present a signaling design for secure integrated sensing and communication (ISAC) systems comprising a dual-functional multi-input multi-output (MIMO) base station (BS) that simultaneously communicates with multiple users while detecting targets present in their vicinity, which are regarded as potential eavesdroppers. In particular, assuming that the distribution of each parameter to be estimated is known a priori, we focus on optimizing the targets’ sensing performance. To this end, we derive and minimize the Bayesian Cramér-Rao bound (BCRB), while ensuring certain communication quality of service (QoS) by exploiting constructive interference (CI). The latter scheme enforces that the received signals at the eavesdropping targets fall into the destructive region of the signal constellation, to deteriorate their decoding probability, thus enhancing the ISAC’s system physical-layer security (PLS) capability. To tackle the nonconvexity of the formulated problem, a tailored successive convex approximation method is proposed for its efficient solution. Our extensive numerical results verify the effectiveness of the proposed secure ISAC design showing that the proposed algorithm outperforms block-level precoding techniques. © 2024, CC BY-NC-ND.

关键词： Quality of service

来源：评论

学校读者我要写书评

暂无评论

Preparation and Properties of Rice Hull Ash as the catalysis supporter in the fluidized-bed reactor

引用

IOP Conference Series: Earth and Environmental science 2021年第1期766卷

作者： Zhaohui Teng Shan Huang Heng Xu Na Li Qulan Zhou College of energy Chengdu University of Tecnoogy Chengdu 610059 China National Key Laboratory of Nuclear Reactor System Design Technology Nuclear Power Institute of China Chengdu 610200 China shenzhen ILNG energy technology CO. LTD Shenzhen 518061 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

This research focuses on the preparation and properties of rice hull ash(RHA). We prepared RHA from combustion of rice husk in the fluidized-bed reactor. The temperature field of the furnace was steady and bellow 850°C to keep SiO2 amorphous. XRD, BET and SEM were applied in the characterization tests to investigate the effect of flow rate(u), the higher primary-secondary wind ratio(i) and relative height of bed material. The optimal combustion condition for preparing RHA was discussed. RHA obtained from rice hull contains abundant amorphous SiO2 (>90%) and the characterization results of RHA show its potential to be a good catalyst supporter.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Unified Rendering Array Driver Runtime Optimization for Graphic Application

引用

IOP Conference Series: Earth and Environmental science 2019年第1期234卷

作者： Chengcheng Ma Ze Tian Honghong Liu Zhao Nie China Aeronautical Computing Research Institute Aviation key Laboratory of Science and Technology on integrated Circuit and Micro-System Design P.O. Box 710068 China Xiangteng microelectronics technology co. LTD P.O. Box 710068 China

As the core of GPU processing, the performance of Unified rendering array is directly affected by the shader driver. On the basis of research the structure of Unified rendering array processing, this paper proposes a runtime Unified rendering array driver optimization method for graphical application, can according to different graphics application scenario runtime to generate optimized Unified rendering array driver, testing on graphics processors FPGA verification environment, driven by the runtime optimization compared with the traditional full function driver, performance increased by 55% - 270%.

关键词：

来源：评论

学校读者我要写书评

暂无评论

α [email protected] carrier modulated platinum single atoms for high-efficient solar cells

引用

Applied Surface science 2023年 611卷

作者： Jixin Yao Jie Wang Wen Wang Ying Meng Haibo Wang Shibin Lu Feng Du Li Yang Xueqin Zuo Guang Li Anhui Province Key Laboratory of simulation and design for Electronic information system Universities Joint Key Laboratory of photoelectric detection Science and Technology in Anhui Province Hefei Normal University Hefei 230601 China School of Materials Science and Engineering Anhui Key Laboratory of Information Materials and Devices Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education Institute of Physical Science and Information Technology Anhui University Hefei 230601 China Institute of Materials Science and Devices School of Materials Science and Engineering Suzhou University of Science and Technology Suzhou 215011 China

Single-atom electrocatalysts have been proven to be the great promising catalysts for energy-related fields yet their active site structure remains elusive, especially in dye-sensitized solar cell (DSSC). Herein, atomically dispersed Pt is anchored into α [email protected] carrier (Pt/α [email protected] ), which vigorously stimulates the activity of Pt single atoms under the strong metal interaction. As expected, the Pt/α [email protected] as the cathode in DSSC exhibits high power conversion efficiency (PCE) of 9.67%, exceeding Pt electrode (7.61%). X-ray photoelectron spectroscopy combined with density functional theory calculations reveals that the high activity is mainly derived from charge re-distribution of Pt/α [email protected] caused by the interaction between Pt atoms and α-MoC. This interaction not only achieves the optimized adsorption/desorption energy of reactants but also brings synergic advantages to expedite the reaction kinetics of the overall system. This work paves further research prospects for charge re-distribution, stimulating electrocatalysts to effectively enhance their catalytic properties by an atomic-level engineering strategy.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Approaching the Fundamental Limit of Orbital Angular Momentum Multiplexing Through a Hologram Metasurface

arXiv

引用

arXiv 2021年

作者： Yuan, Shuai S.A. Wu, Jie Chen, Menglin L.N. Lan, Zhihao Zhang, Liang Sun, Sheng Huang, Zhixiang Chen, Xiaoming Zheng, Shilie Jiang, Li Jun Zhang, Xianmin Sha, Wei E.I. College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China Ministry of Education The Key Laboratory of Electromagnetic Environmental Sensing Department of Education of Anhui Province Anhui University Hefei230039 China Department of Electrical and Electronic Engineering The University of Hong Kong Hong Kong Department of Electronic and Electrical Engineering University College London Torrington Place LondonWC1E 7JE United Kingdom Anhui Province Key Laboratory of Simulation and Design for Electronic Information System Hefei Normal University Hefei230601 China School of Electronic Science and Engineering University of Electronic Science and Technology of China Chengdu611731 China School of Information and Communications Engineering Xi’an Jiaotong University Xi’an710049 China

Establishing and approaching the fundamental limit of orbital angular momentum (OAM) multiplexing are necessary and increasingly urgent for current multiple-input multiple-output research. In this work, we elaborate the fundamental limit in terms of independent scattering channels (or the degrees of freedom of scattered fields) through angular-spectral analysis, in conjunction with a rigorous Green’s function method. The scattering-channel limit is universal for arbitrary spatial-mode multiplexing, which is launched by a planar electromagnetic device, such as antenna, metasurface, etc., with a predefined physical size. As a proof of concept, we demonstrate both theoretically and experimentally the limit by a phase-only metasurface hologram that transforms orthogonal OAM modes to plane-wave modes scattered at critically separated angular-spectral regions. Particularly, a minimax optimization algorithm is applied to suppress angular-spectrum aliasing, achieving good performances in both full-wave simulation and experimental measurement at microwave frequencies. This work offers a theoretical upper bound and corresponding approach route for engineering designs of OAM multiplexing. Copyright © 2021, The Authors. All rights reserved.

关键词： Spectrum analysis

来源：评论

学校读者我要写书评

暂无评论

Forecasting Covid-19 New Cases Through the Mixed Generalized Inverse Weibull Distribution and Time Series Model

SSRN

引用

SSRN 2023年

作者： Chang, Yiming Tao, YinYing Shan, Wei Yu, Xiangyuan No.37 Xueyuan Road Haidian District Beijing China School of Design and Fashion Zhejiang University of Science and Technology No.318 Liuhe Road Xihu District Zhejiang Hangzhou China School of Economics and Management Beihang University No.37 Xueyuan Road Haidian District Beijing China Key Laboratory of Complex System Analysis and Management Decision Ministry of Education No.37 Xueyuan Road Haidian District Beijing China School of Economics and Management Beijing Jiaotong University No.3 Shangyuancun Haidian District Beijing China

In this paper, the MGIW-ARIMA model is proposed to predict the newly diagnosed cases of COVID-19. The MGIW model is used to predict the trend components, and the ARIMA model is used to predict the random components. Finally, the estimated results of trend components and random components are added together to get the eventual predictions. The data of COVID-19 in the United States is used to verify and evaluate the model. In the short-term prediction, the combined model of MGIW-ARIMA is better than the single MGIW model. In the long-term prediction, the prediction accuracy of the MGIW model is slightly higher than that of the MGIW- ARIMA model. The MGIW-ARIMA model proposed in this paper makes up for the shortcoming of the lack of randomness in the estimated values of the MGIW model. The combination model can effectively capture the short-term changes of the epidemic while grasping the long-term development trend. © 2023, The Authors. All rights reserved.

关键词： COVID-19

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：