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Machine Learning for 5G and Beyond:From ModelBased to Data-Driven Mobile Wireless Networks

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China Communications 2019年第1期16卷 165-175页

作者： Tianyu Wang Shaowei Wang zhi-hua Zhou National Key Laboratory for Novel Software Technology Nanjing University School of Electronic Science and Engineering Nanjing University

During the past few decades,mobile wireless communications have experienced four generations of technological revolution,namely from 1 G to 4 G,and the deployment of the latest 5 G networks is expected to take place in *** fundamental question is how we can push forward the development of mobile wireless communications while it has become an extremely complex and sophisticated *** believe that the answer lies in the huge volumes of data produced by the network itself,and machine learning may become a key to exploit such *** this paper,we elaborate why the conventional model-based paradigm,which has been widely proved useful in pre-5 G networks,can be less efficient or even less practical in the future 5 G and beyond mobile ***,we explain how the data-driven paradigm,using state-of-the-art machine learning techniques,can become a promising *** last,we provide a typical use case of the data-driven paradigm,i.e.,proactive load balancing,in which online learning is utilized to adjust cell configurations in advance to avoid burst congestion caused by rapid traffic changes.

关键词： mobile wireless networks data-driven paradigm machine learning

PIV analysis and high-speed photographic observation of cavitating flow field behind circular multi-orifice plates

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Water Science and Engineering 2020年第2期13卷 145-153页

作者： zhi-ping Guo Xi-huan sun zhi-yong Dong College of Hydro-Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China Department of Transportation Engineering Shanxi Conservancy Technical InstituteYuncheng 044004China College of Civil Engineering and Architecture Zhejiang University of TechnologyHangzhou 310014China

Based on a self-developed hydrodynamic cavitation device with different geometric parameters for circular multi-orifice plates,turbulence characteristics of cavitating flow behind multi-orifice plates,including the effects of orifice number and orifice layout on longitudinal velocity,turbulence intensity,and Reynolds stress,were measured with the particle image velocimetry(PIV)*** regimes of the cavitating flow were also observed with high-speed *** experimental results showed the following:(1)high-velocity multiple cavitating jets occurred behind the multi-orifice plates,and the cavitating flow fields were characterized by topological structures;(2)the longitudinal velocity at each cross-section exhibited a sawtooth-like distribution close to the multi-orifice plate,and each sawtooth indicated one jet issuing from one orifice;(3)there were similar magnitudes and forms for the longitudinal and vertical turbulence intensities at the same cross-section;(4)the variation in amplitude of Reynolds stress increased with an increase in orifice number;and(5)the cavitation clouds in the flow fields became denser with the increase in orifice number,and the clouds generated by the staggered layout of orifices were greater in number than those generated by the checkerboard-type one for the same orifice *** experimental results can be used to analyze the mechanism of killing pathogenic microorganisms through hydrodynamic cavitation.

关键词： Cavitating flow Circular multi-orifice plate PIV technique High-speed photography Turbulence characteristics

Distribution of platinum group elements in road dust in the Beijing metropolitan area, China

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Journal of Environmental Sciences 2007年第1期19卷 29-34页

作者： WANG Juan ZHU Ruo-hua SHI Yan-zhi Department of Chemistry Capital Normal University Beijing 100037 China

Dust samples collected from the Beijing metropolitan area （China） were evaluated to determine the distribution and the concentration of platinum group elements （PGEs）. The dust particles that were smaller than 100 mesh size fraction （150 μm） were analyzed after aqua regia digestion. Concentrations ofPt, Rh, and Pd were found to be between 3.96 and 356.3 ng/g, 2.76 and 97.11 ng/g, and 0.1 and 124.9 ng/g, respectively, in the urban areas of Beijing, whereas for the background samples collected from the suburbs of Beijing, the concentrations of Pt, Pd, and Rh were very low and ranged from 0.1 to 0.9 ng/g, 0.5 to 1.4 ng/g, and 0.8 to 2.2 rig/g, respectively. The distributions of PGEs in road dust were an accurate reflection of the levels of pollution and were found to match with the local traffic conditions. A strong positive correlation was established among all the dements found in road dust. This suggests that emissions of abraded fragments from vehicle exhausts may be the source of the high concentration of Pt, Rh, and Pd in road dust along the main roads of Beijing.

关键词： platinum (Pt) palladium (Pd) rhodium (Rh) road dust distribution environmental pollution

Majorana zero mode in the vortex of an artificial topological superconductor

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Science China(Physics,Mechanics & Astronomy) 2017年第5期60卷 49-59页

作者： Hao-hua sun Jin-Feng Jia Key Laboratory of Artificial Structures and Quantum Control(Ministry of Education) Department of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

Majorana fermion （MF）, an exotic particle that is identical to its own antiparticle, was recently found in solid matter as a quasiparticle excitation, the Majorana zero mode （MZM）, in the vortex of an artificial topological superconductor （TSC）. This artificial TSC, first proposed by Fu and Kane in 2008, is a heterostructure made of a topological insulator BiETe3 and an s-wave superconductor NbSe2. This paper will briefly review the experimental progresses based on the Bi2Te3/NbSe2 heterostructure. All evidences are self-consistent and reveal that the MZM exists in the center of vortex. Those experimental results are also supported by theory. This finding is a milestone in the research ofMajorana fermions in solid state physics and a starting point of MZM＇s application in topological quantum computation.

关键词： Majorana fermion Majorana zero mode topological superconductor heterostructure vortex

Seaweed glue as a novel polymer depressant for the selective separation of chalcopyrite and galena

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International Journal of Minerals,Metallurgy and Materials 2019年第12期26卷 1495-1503页

作者： Xiong Chen Guo-hua Gu zhi-xiang Chen School of Minerals Processing and Bioengineering Central South University

The use of seaweed glue(SEG)as a novel polymer depressant for the separation of chalcopyrite from galena with butyl xanthate(BX)as a collector was studied through microflotation *** angle,adsorption,dynamic potential,and infrared spectral analyses were conducted to clarify the mechanism underlying the action of SEG on *** results of microflotation experiments indicated that chalcopyrite could be selectively separated from galena by using a SEG depressant concentration of 15 mg·L^-1,BX concentration of 10 mg·L^-1,and methyl isobutyl carbinol concentration of 8.5 mg·L^-1 at pH 8.0.A Cu concentrate with a grading of 23.68wt% was obtained at a recovery rate of 81.52% from mixed minerals with 8.29wt% Cu *** angle analysis showed that the effect of SEG on the wettability of galena was stronger than that on the wettability of ***,zeta potential,and FT-IR spectral analyses revealed that SEG and BX were coadsorbed on the surfaces of *** depressed galena by covering xanthate ions in the functional groups of-COO and mainly underwent weak physisorption on *** mechanisms account for the ability of SEG to depress galena effectively while enabling chalcopyrite flotation.

关键词： seaweed glue chalcopyrite galena flotation separation

用海藻酸钙包埋法固定化蓝色梨头霉菌生产氢化可的松的初步研究

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天津轻工业学院学报 2003年第4期18卷 1-4页

作者：范志华孙爱友郝建东许春英天津科技大学食品科学与生物工程学院天津300222

初步研究了海藻酸钙包埋法固定化技术在氢化可的松生产中的应用。确定了底物R.S.A的最佳投料时间为32h、最适的固定化梨头霉菌孢子液浓度为5×106个/mL,选择洗衣粉作为表面活性剂的最适添加量为0.04%。确定了固定化霉菌培养基的最优组... 详细信息

初步研究了海藻酸钙包埋法固定化技术在氢化可的松生产中的应用。确定了底物R.S.A的最佳投料时间为32h、最适的固定化梨头霉菌孢子液浓度为5×106个/mL,选择洗衣粉作为表面活性剂的最适添加量为0.04%。确定了固定化霉菌培养基的最优组成。结果表明,固定化的梨头霉菌重复使用5次以后,其羟基化酶的转化能力没有明显下降。

关键词：海藻酸钙包埋法固定化技术氢化可的松梨头霉菌培养基药物转化率底物投料浓度

Study of main factors influencing unsteady-state temperature drop in oil tank storage under dynamic thermal environment coupling

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Petroleum Science 2023年第6期20卷 3783-3797页

作者： Wei sun Ming-Yang Li Yu-Duo Liu Qing-Lin Cheng Li-Xin Zhao Shuai Shao zhi-hua Wang Key Laboratory for Enhancing Oil&Gas Recovery of Ministry of Education Northeast Petroleum UniversityDaqing163318HeilongjiangChina

With the increasing oil demand, the construction of oil energy reserves in China needs to be further strengthened. However, given that there has been no research on the main influencing factors of crude oil temperature drop in storage tanks under actual dynamically changing environments, this paper considers the influence of dynamic thermal environment and internal crude oil physical properties on the fluctuating changes in crude oil temperature. A theoretical model of the unsteady-state temperature drop heat transfer process is developed from a three-dimensional perspective. According to the temperature drop variation law of crude oil storage tank under the coupling effect of various heat transfer modes such as external forced convection, thermal radiation, and internal natural convection, the external dynamic thermal environment influence zone, the internal crude oil physical property influence zone, and the intermediate transition zone of the tank are proposed. And the multiple non-linear regression method is used to quantitatively characterize the influence of external ambient temperature, solar radiation, wind speed, internal crude oil density, viscosity, and specific heat capacity on the temperature drop of crude oil in each influencing zone. The results of this paper not only quantitatively explain the main influencing factors of the oil temperature drop in the top, wall, and bottom regions of the tank, but also provide a theoretical reference for oil security reserves under a dynamic thermal environment.

关键词： Oil temperature drop Forced convection Natural convection Dynamic thermal environment Quantitative analysis

Computational fluid dynamic simulation of an inter-phasing pulse tube cooler

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第1期9卷 93-98页

作者： Xiao-bin ZHANG zhi-hua GAN Li-min QIU hua-xiang LIU Institute of Refrigeration and Cryogenics Zhejiang University Hangzhou 310027 China College of Science Guangdong Ocean University Zhanjiang 524088 China

An inter-phasing pulse tube cooler (IPPTC) consists of two pulse tube units, which are connected to each other at hot ends of the pulse tubes through a needle valve. This paper presents the computational fluid dynamic (CFD) results of an IPPTC using a 2D axis-symmetrical model. General results such as the phase difference between pressure and velocity at cold end and hot end, the temperature profiles along the wall, the available lowest temperature as well as its oscillations and the coefficient of performance (COP) for IPPTC are presented. The formation of DC flow and its effects on the performance of the cooler are investigated and analyzed in detail. Turbulence, which is partially responsible for the poor overall performance of a single orifice pulse tube cooler (OPTC), is found to be much reduced in IPPTC and its performance is improved significantly compared with the single OPTC.

关键词： Inner-phasing Pulse tube cooler (PTC) Computational fluid dynamic (CFD)

Some Existence Theorems on Path Factors with Given Properties in Graphs

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Acta Mathematica Sinica,English Series 2020年第8期36卷 917-928页

作者： Si Zhong ZHOU zhi Ren sun School of Science Jiangsu University of Science and TechnologyZhenjiang 212003P.R.China School of Mathematical Sciences Nanjing Normal UniversityNanjing 210046P.R.China

A path factor of G is a spanning subgraph of G such that its each component is a path.A path factor is called a P≥n-factor if its each component admits at least n vertices.A graph G is called P≥n-factor covered if G admits a P≥n-factor containing e for any e∈E(G),which is defined by[Discrete Mathematics,309,2067-2076(2009)].We first define the concept of a(P≥n,k)-factor-critical covered graph,namely,a graph G is called(P≥n,k)-factor-critical covered if G-D is P≥n-factor covered for any D⊆V(G)with|D|=*** this paper,we verify that(i)a graph G withκ(G)≥k+1 is(P≥2,k)-factor-critical covered if bind(G)>2+k/3;(ii)a graph G with|V(G)|≥k+3 andκ(G)≥k+1 is(P≥3,k)-factor-critical covered if bind(G)≥4+k/3.

关键词： Graph binding number P≥2-factor P≥3-factor (P≥2,k)-factor-critical covered graph (P≥3,k)-factor-critical covered graph