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Modeling of air quality with a modified two-dimensional Eulerian model: A case study in the Pearl River Delta (PRD) region of China

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Journal of Environmental Sciences 2007年第5期19卷 572-577页

作者： CHENG Yan-li BAI yu-hua li jin-long liU Zhao-rong College of Environmental Sciences Peking University Beijing 100871 China

A modified two-dimensional Eulerian air quality model was used to simulate both the gaseous and particulate pollutant concentrations during October 21-24, 2004 in the Pearl River Delta （PRD） region, China. The most significant improvement to the model is the added capability to predict the secondary organic aerosols （SOA） concentrations because of the inclusion of the SOA formation chemistry. The meteorological input data were prepared using the CALMET meteorological model. The concentrations of aerosol-bound species such as NO3^-, NH4^＋, SO4^2-, and SOA were calculated in the fine particle size range （〈2.5 μm）. The results of the two-dimensional model were compared to the measurements at the ground level during the PRD Intensive Monitoring Campaign （IMC）. Overall, there were good agreements between the measured and modeled concentrations of inorganic aerosol components and O3. Both the measured and the modeled results indicated that the maximum hourly O3 concentrations exceeded the China National Air Quality Standard. The predicted 24-h average SOA concentrations were in reasonable agreement with those predicted by the method of minimum OC/EC ratio.

关键词： air quality model numerical simulation secondary organic aerosol inorganic aerosol

Chemical additives affect sulfate reducing bacteria biofilm properties adsorbed on stainless steel 316L surface in circulating cooling water system

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Frontiers of Environmental Science & Engineering 2017年第2期11卷 143-156页

作者： yu Qi jin li Rui liang Sitong Ji Jianxiang li Meng liu Research Center for Aqueous Organic Pollutants Control and Water Quality Security Beijing Key Laboratory Beijing Jiaotong University Beijing 100044 China

This paper studied the biofilm properties and corrosion behavior of sulfate reducing bacteria （SRB） on stainless steel 316L （SS316L） surface in circulating cooling water system with and without additives including hydroxy ethyl fork phosphonic acid （HEDP）, dodecyl dimethyl benzyl anunonium chlotide （1227） and NaClO. Biochemical technique, electrochemical technology, X-ray photoelectron spectroscopy （XPS） and scanning electron microscope （SEM） were used. The results show that the extracellular polymeric substance （EPS） in biofilm attached on the SS316L surface mainly contain proteins and polysaccharides, the contents are 98 ***-2 and ***-2, respectively. The polysaccharides were cut by 1227 about 80%, while 55% by NaCIO. The proteins were reduced by NaCIO about 53%, while only 30% by 1227. The potentiodynamic polarization shows that the corrosion potential of SS316L was enhanced from -0.495 V to -0.390 V by the chemical additive delaying the occurrence of the corrosion. And the corrosion rate was also reduced from 5.19 × 10^-3 mm·a^-1 to 2.42 × 10^-3 mm＇a . But NaCIO stdl caused pitting corrosion after stenhzmg the bacteria, while 1227 can form a protective film on the surface of SS316L. Though HEDP contribute to the bacteria activity, it can enhance the breakdown potential. XPS results confirmed that 1227 can change the value of C：O in the biofilm attached on metal surface, and NaCIO can eliminate the existence of amidogen. This study would provide some recommendations for the selection of chemical additives in the thermal power plant.

关键词： Sulfate reducing bacteria (SRB)Chemical additivesBiofilmExtracellular polymeric substance (EPS)Microbe conosion

Empirical likelihood for AR-ARCH Models Based on LAD Estimation

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Acta Mathematicae Applicatae Sinica 2012年第2期28卷 371-382页

作者： jin-yu li Wei liang Shu-yuan He School of Sciences China University of Mining and Technology Xuzhou 221116 China School of Mathematical Sciences Peking University Beijing 100871 China School of Mathematical Sciences Capital Normal University Beijing 100048 China

By employing the empirical likelihood method, confidence regions for the stationary AR（p）-ARCH（q） models are constructed. A self-weighted LAD estimator is proposed under weak moment conditions. An empirical log-likelihood ratio statistic is derived and its asymptotic distribution is obtained. Simulation studies show that the performance of empirical likelihood method is better than that of normal approximation of the LAD estimator in terms of the coverage accuracy, especially for relative small size of observation.

关键词： AR-ARCH model confidence region empirical likelihood LAD estimation

Synthesis and Photo-acid Generation of a Novel Bis(trichloromethyl)-1,3,5-triazine

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Chemical Research in Chinese Universities 2009年第6期25卷 870-875页

作者： JIANG yu-ren li jin-liang XU Hui College of Chemistry and Chemical Engineering Central South University Changsha 410083 P. R. China

A new environmentally friendly photo-acid generator（PAG）, 1-{4＇-[4,6-bis（trichloromethyl）-1,3,5-triazin- 2-yl] [ 1, 1＇-biphenyl]-4-yl}-O-acetyloxime ethanone（TZ4） consisting of both an oxime ester group and a triazine group was designed and synthesized. From the measurements of absorption, fluorescence and the photo-acid generation, it was found that the novel PAG has an excellent radical-generating efficiency. And the other three bis-（trichloromethyl） triazine derivatives 2-[2-（4-methoxyphenyl）ethenyl]-4,6-bis（trichloromethyl）-l,3,5-triazine（TZ1）, 2-[2-（3,4-dimethoxyphenyl）ethenyl]-4,6-bis（trichloromethyl）-1,3,5-triazine（TZ2） and 2-（1,3-benzodioxol-5-yl）-4,6-bis（trichloromethyl）-1,3,5-triazine（TZ3） were synthesized and studied in this work. In the acid measurement, the acid-forming performance of S-triazinyl derivatives was evaluated by the method ascertained in our laboratory. The results indicate that the novel triazine has the better acid-forming performance that subsequently catalyzes the deblocking of a protecting group in copolymers.

关键词： Triazine Photo-acid generator Photo-sensitizer Acid production efficiency

Effect of Azoxystrobin on Oxygen Consumption and cyt b Gene Expression of Colletotrichum capsici from Chilli Fruits

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Agricultural Sciences in China 2009年第5期8卷 628-631页

作者： CHEN yu jin li-hua ZHOU Ming-guo College of Plant Protection Nanjing Agricultural University~Key Laboratory of Monitoring and Management of Crop Diseases and PestInsects Ministry of Agriculture Nanjing 210095 P.R. China

Azoxystrobin acts as an inhibitor of electron transport by binding to the Qo center of cytochrome b （cyt b）. Resistance to azoxystrobin was usually caused by the point mutation of cyt b gene or by the induction of alternative respiration. Oxygen consumption test for mycelia of Colletotrichum capsici showed that azoxystrobin inhibited mycelial respiration within 12 h; however, as time went on, the respiration of the mycelia recovered when the mycelia were treated with azoxystrobin and salicylhydroxamic acid （SHAM, a known inhibitor of alternative respiration）, and the oxygen consumption of the mycelia could not be inhibited. Meanwhile, cytochrome b （cyt b） gene expression increased with the recovery of mycelial respiration. The increased cyt b gene expression might play a role in the development of resistance to azoxystrobin in C. capsici.

关键词： QoI fungicides gene expression chili fungal respiration azoxystrobin resistance

Microstructure of Hydrogen-Implanted Polycrystalline α-SiC after Annealing

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Chinese Physics Letters 2018年第9期35卷 50-52页

作者： Hui-Ping liu jin-yu li Bing-Sheng li Institute of Modern Physics Chinese Academy of Sciences

Microstructural evolution in H-implanted polycrystalline a-SiC upon thermal annealing at temperature 1100℃ is studied. After annealing, the samples are examined via cross-sectional transmission electron microscopy （XTEM） analysis. H2 gas bubbles are formed during H implantation and some H2 molecules are released from the bubble to form cavities during thermal annealing. The distribution and size of the observed cavities are related to the implantation fluence. The results are compared to H implanted single crystal SiC and He implanted polycrystalline α-SiC. The possible reasons are discussed.

关键词： Microstructure of Hydrogen-Implanted Polycrystalline SiC after Annealing

Microstructural features and precipitation behavior of Ti,Nb and V microalloyed steel during isothermal processing

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Journal of Iron and Steel Research International 2019年第1期26卷 102-111页

作者： Qi Zhou Zhuang li Zhan-shan Wei Di Wu jin-yu li Zhen-yao Shao School of Environment and Chenlical Engineering Shenyang Ligong UniversityShenyang 110159LiaoningChina College of Materials Science and Engineering Shenyang Aerospace UniversityShenyang 110136LiaoningChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110004LiaoningChina

Thermal simulations of Ti,Nb and V microalloyed steel were conducled using a thermomechanical simulator,and the microstructural evolution and the precipitation behavior during isothermal processing were *** results show that with increasing holding time,the microstructural constituents change from the martensite and bainitic ferrites to granular bainite and polygonal *** maximum hardness is obtained for the specimen after isothermal holding for 5s due to the martensite strengthening *** hardness of the specimen decreases after isothermal holding for 10s,because the strengthening contribution of fine dispersed precipitates becomes *** hardness values of the specimens increase and then remain high after isothermal holding for 60 and *** is attributed to the contribution of the interphase precipitation hardening to the hardness of the studied *** precipitates in the specimen are coarsened after isothermal holding for 3600s,even though the coarsening is not *** precipitates are fee(***)(N.C)particles and belong to the MX-type *** beneficial effects of precipitation strengthening are *** hardness decreases to a minimum hardness value due to the presence of large amounts of polygonal ferrite after isothermal holding for *** coarse precipitates are the primary origin of the hardness decrease.

关键词： Microalloyed steel Isothermal holding time Microstructural constituent Precipitation Hardness

Spherical nanoindentation stress–strain responses of SIMP steel to synergistic effects of irradiation by H and He ions

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Nuclear Science and Techniques 2022年第6期33卷 139-147页

作者： Peng jin Tie-Long Shen jing li yu-Shan Yang Jian-Long Chai Ya-Bin Zhu Ming-Huan Cui Chao liu Tong-Min Zhang Long Kang Jun li jin-yu li Shuo-Xue jin Xing-Zhong Cao Zhi-Guang Wang Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

A novel Fe-10Cr ferritic/martensitic steel called SIMP was chosen to investigate synergistic effects of H and He on the mechanical properties of structural materials for innovative nuclear energy systems. Sequential and separate irradiation experiments on SIMP steel specimens at room temperature using H and He ions with various energy levels were conducted to produce an ion deposition plateau at 300-650 nm. The indentation stress-strain responses were examined using spherical nanoindentation tests after the irradiation experiments. It was found that the sequential irradiation by He and H produced a higher indentation yield stress than separate irradiation, indicating that the hardening was enhanced by the synergy of the H and He irradiation. The micro-mechanism responsible for enhancing the hardening of the SIMP steel through the H and He synergy was investigated using Doppler broadening spectroscopy detection and transmission electron spectroscopy observations.

关键词： H/He irradiation Spherical nanoindentation Bubbles Dislocation loops

Joint frequency offset tracking and PAPR reduction algorithm in OFDM systems

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Journal of Systems Engineering and Electronics 2010年第4期21卷 557-561页

作者： lijun Ge Yingxin Zhao Hong Wu Ning Xu yu'ang jin Wenqi li College of Information Technical Science Nankai University Tianjin 300071 E R. China

This paper presents an algorithm that aims to reduce the peak-to-average power ratio（PAPR） of orthogonal frequency division multiplexing（OFDM） communication systems while maintaining frequency *** algorithm achieves PAPR reduction by applying the complex conjugates of the data symbol obtained from the frequency domain to cancel the phase of the data symbol.A likelihood estimator is used to obtain the sub-carrier phase error due to the residual carrier frequency offset（RCFO） using the same complex conjugates as a pilot ***,a joint time and frequency domain multicarrier phase locked loop（MPLL） is developed to compensate additional frequency *** results show that this algorithm is capable of reducing PAPR without impacting the frequency tracking performance.

关键词： orthogonal frequency division multiplexing(OFDM) peak-to-average power ration(PAPR) carrier frequency offset complex conjugate multicarrier phase locked loop(MPLL) phase error.