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A remote sensing system of vehicle emissions based on tunable diode laser technology

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Journal of Environmental Sciences 2006年第1期18卷 154-157页

作者： zeng Jun guo Hua-fang HU Yue-ming College of Automation Science and Engineering South China University of Technology Guangzhou 510640 China

As being an effective real-time method of monitoring vehicle emissions on-road, a remote sensing system based on the tunable diode laser （TDL） technology was presented, and the key technologies were discussed. A field test in Guangzhou（Guangdong, China） was performed and was found that the factors, such as slope, instantaneous speed and acceleration, had significant influence on the detectable rate of the system. Based on the results, the proposal choice of testing site was presented.

关键词： remote sensing tunable diode laser vehicle emission detectable rate

The Mobility of Threadedα-Cyclodextrins in PR Copolymer and Its Influences on Mechanical Properties

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Chinese Journal of Polymer Science 2017年第6期35卷 752-763页

作者： Zhi Yan 叶霖 Ai-ying Zhang zeng-guo Feng School of Materials Science and Engineering Beijing Institute of Technology Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications

The methylated polyrotaxane （MePR） copolymer was prepared via the methylation of hydroxyl of threaded α-cyclodextrin （α-CDs） in polyrotaxane （PR） copolymer by CH3I/NaH. Its structure was characterized by GPC, IR and NMR. The WXRD and TGA measurements showed the destruction of channel-like crystalline structure in MePR copolymer. The sliding of threaded α-CDs along PEG axis in PR and MePR copolymers was demonstrated by their dielectric spectra that also evidenced the presence of rotating of threaded α-CDs around PEG axis in MePR eopolymer. The frequent and vigorous molecular mobility in MePR and PR copolymers was also verified by dynamic mechanical analysis （DMA） and rheological measurement, which was possibly assigned to the sliding and rotating of threaded α-CDs. DMA and rheological results showed that the mobility of α-CDs could simultaneously strengthen and toughen PR copolymer proved by stress-stain curves. In this paper, we report the CD mobility in PR and MePR copolymers. The macroscopic behaviors of PR copolymer, such as mechanical properties in solid state, were also found to be benefited from CD mobility.

关键词： PR copolymer Methylation CD mobility Dielectric measurement Mechanical property

M_(φ)-type Submodules over the Bidisk

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Acta Mathematica Sinica,English Series 2021年第5期37卷 805-824页

作者： guo zeng YANG Chang Hui WU Tao YU School of Mathematics and Statistics Zhengzhou Normal UniversityZhengzhou 450044P.R.China School of Mathematical Sciences Qufu Normal UniversityQufu 273165P.R.China School of Mathematical Sciences Dalian University of TechnologyDalian 116024P.R.China

Let H^(2)(D^(2))be the Hardy space over the bidisk D^(2),and let M_(φ)=[(z-φ(w))^(2)]be the submodule generated by(z-φ(w))^(2),whereφ(w)is a function in H∞(w).The related quotient module is denoted by N_(φ)=H^(2)(D^(2))ΘM_(φ).In the present paper,we study the Fredholmness of compression operators S_(z),S_(w) on N_(φ).Whenφ(w)is a nonconstant inner function,we prove that the Beurling type theorem holds for the fringe operator F_(w) on[(z-w)^(2)]Θz[(z-w)^(2)]and the Beurling type theorem holds for the fringe operator Fz on M_(φ)ΘwM_(φ)ifφ(0)=***,we study some properties of F_(w) on[(z-w^(2))^(2)]Θz[(z-w^(2))^(2)].

关键词： Submodules Beurling type theorem compression operators Fredholmness

An assessment method of annual climatic status in China using extreme climate indices:2021 as an example

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Advances in Climate Change Research 2022年第6期13卷 868-874页

作者： zeng-Yuan guo Li-Juan CHEN Bing XIE Climate Studies Key Laboratory National Climate CenterChina Meteorological AdministrationBeijing 100081China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science&TechnologyNanjing 210044China

A proper assessment of annual climatic status(ACS)is conducive to rationally formulating disaster prevention and mitigation *** former definition of ACS lacks either information on extreme climate or an intuitive grade feature service to the *** ACS defined in the National Standard of the People's Republic of China(GBACS)only considers the accumulated climate effects of each weighted 10-d temperature/precipitation anomaly in a *** global warming,the losses caused by extreme climate events often have a significant impact on the grades of ACS,but this impact cannot be reasonably reflected by *** study proposed the assessment of ACS using extreme climate indices(extreme climate-based ACS(ECACS))and compared it with *** results indicated that GBACS and ECACS can be used to evaluate the ACS from different *** ECACS is an important supplement to the GBACS,especially considering the years with frequently occurring extreme climate *** sum of GBACS and ECACS is a reasonable and comprehensive way to evaluate the *** empirical orthogonal function(EOF)analysis indicated a uniform mode(EOF1)and a dipole mode(EOF2)in GBACS and ECACS in *** interannual variation characteristics of ECACS in northern and southern China(EOF2 pattern)are consistent with real climate features,which is conducive to providing better and more detailed regional information in the ACS forecast *** results have essential instructive and application value for ACS assessment and government decision making.

关键词： Extreme climate indices Annual climatic status Temperature Precipitation

Molecular Dynamics Simulation on Interface Characteristics of Micro Droplets

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Chinese Physics Letters 1999年第11期16卷 803-804页

作者： YANG Chun CHEN Min guo zeng-yuan Department of Engineering Mechanics Tsinghua UniversityBeijing 100084

Liquid droplets of argon surrounded by the vapor for various temperatures have been simulated by the molecular dynamics method. Macroscopic characteristics of droplets such as density, pressure and temperature profiles are evaluated with emphasis on the temperature characteristics, which was usually regarded uniform in the surface region for an equilibrium liquid-vapor system. The 12-6 Lennard-Jones potential and periodic boundary conditions are employed in the 1000-particles three-dimensional simulation. What differs from the literatures is that the temperature in the surface region is not uniform, but exhibits a curve with two extrema. The peak and valley values are higher and lower than the bulk saturation temperature respectively. The magnitude of the peak and valley values becomes smaller when the saturation temperature is closer to the critical temperature.

关键词： temperature. saturation closer

Monte Carlo Simulation of Argon in Nano-Space

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Chinese Physics Letters 2000年第5期17卷 313-315页

作者： CHEN Min YANG Chun guo zeng-Yuan Department of Engineering Mechanics Tsinghua UniversityBeijing 100084

Monte Carlo simulations are performed to investigate the thermodynamic properties of argon conBned in nano-scale cubes constructed of graphite walls.A remarkable depression of the system pressures is *** simulations reveal that the length-scale of the cube,the magnitude of the interaction between the fluid and the graphite wall and the density of the fluid exhibit reasonable effects on the thermodynamic property shifts of the Buid.

关键词： walls property Simulation

Three-Dimensional Molecular Dynamics Simulation on Heat Propagation in Liquid Argon

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Chinese Physics Letters 2001年第1期18卷 71-73页

作者： guo Ying-Kui guo zeng-Yuan LIANG Xin-Gang Department of Engineering Mechanics Tsinghua UniversityBeijing 100084

The propagation behaviour of an initial thermal perturbation in liquid argon is simulated by the molecular dynamics *** 12-6 Lennard-Jones potential and mirror boundary conditions are employed in the 32768particle three-dimensional *** characteristics such as the kinetic temperature,pressure and momentum profiles are monitored during the simulation in order to examine the heat propagation behaviour under a timescale comparable with the relaxation *** results show that the behaviour is still diffusionlike;no features predicted by the Cattaneo-Vernotte model have been *** wave-like front of the local temperature may be caused by the adiabatic compression and expansion by the pressure wave generated by the thermal expansion.

关键词： behaviour thermal relaxation

Factors affecting the formation of trihalomethanes in the presence of bromide during chloramination

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第8期11卷 606-612页

作者： Yong-ji ZHANG Ling-ling ZHOU guo zeng Zheng-guo SONG Gui-bai LI Key Laboratory of Yangtze River Water Environment Ministry of Education Tongji University Shanghai 200092 China State Key Laboratory of Pollution Control and Resources Reuse Tongji University Shanghai 200092 China School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 China

The effects of the concentration of dissolved total organic carbon (TOC), the TOC/Br- ratio, bromide ion levels, the chlorine to ammonia-N ratio (Cl:N), the monochloramine dose and the chlorine dose on the formation of trihalomethanes (THMs) (including chloroform, bromodichloromethane, chlorodibromomethane, and bromoform) from chlorination were investigated using aqueous humic acid (HA) solutions. The profile of the chloramine decay was also studied under various bromide ion concentrations. Monochloramine decayed in the presence of organic material and bromide ions. The percentage of chloroform and brominated THMs varied according to the TOC/Br- ratio. Total THMs (TTHMs) formation increased from 112 to 190 μg/L with the increase concentrations of bromide ions from 0.67 to 6.72 mg/L, but the chlorine-substituted THMs were replaced by bromine-substituted THMs. A strong linear correlation was obtained between the monochloramine dose and the formation of THMs for Cl:N ratios of 3:1 and 5:1. These ratios had a distinct effect on the formation of chloroform but had little impact on the formation of bromodichloromethane or chlorodibromomethane. The presence of bromide ions increased the rate of monochloramine decay.

关键词： Trihalomethanes (THMs) Humic acid (HA) Bromide Monochloramine

Impact of total organic carbon and chlorine to ammonia ratio on nitrification in a bench-scale drinking water distribution system

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Frontiers of Environmental Science & Engineering 2010年第4期4卷 430-437页

作者： Yongji ZHANG Lingling ZHOU guo zeng Huiping DENG Guibai LI Key Laboratory of Yangtze River Water Environment Ministry of Education(Tongji University)Shanghai 200092China State Key Laboratory of Pollution Control and Resources Reuse Tongji UniversityShanghai 200092China School of Municipal and Environmental Engineering Harbin Institute of TechnologyHarbin 150090China

Nitrification occurs in chloraminated drinking water systems and is affected by water quality *** aim of this study was to investigate the impact of total organic carbon and chlorine to ammonia ratio on nitrification potential in a simulated drinking water distribution system as during *** occurrence of nitrification and activity of nitrifying bacteria was primarily monitored using four rotating annular bioreactors(RAB)with different chlorine to ammonia ratios and total organic carbon(TOC)*** results indicated that nitrification occurred despite at a low influent concentration of ammonia,and a high concentration of nitrite nitrogen was detected in the *** study illustrated that reactors 1(R1)and 3(R3),with higher TOC levels,produced more nitrite nitrogen,which was consistent with the ammonia-oxidizing bacteria(AOB)counts,and was linked to a relatively more rapid decay of chloramines in comparison to their counterparts(R2 and R4).The AOB and HPC counts were correlated during the biofilm formation with the establishment of *** AOB abundance was also higher in the high TOC reactors compared with the low TOC *** chlorine to ammonia ratio did not have a significant impact on the occurrence of *** water with a high TOC level supported the occurrence of nitrification,and AOB development occurred at all examined chlorine to ammonia dose ratios(3:1 or 5:1).

关键词： nitrification drinking water ammoniaoxidizing bacteria(AOB) chloramines organic carbon heterotrophic bacteria