|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | Chemical characteristics of PM_(2.5) during a typical haze episode in Guangzhou显示文摘The chemical characteristics(water-soluble ions and carbonaceous species) of PM2.5 in Guangzhou were measured during a typical haze episode.Most of the chemical species in PM2.5 showed significant difference between normal and haze days.The highest contributors to PM2.5 were organic carbon(OC),nitrate,and sulfate in haze days and were OC,sulfate,and elemental carbon(EC) in normal days.The concentrations of secondary species such as,NO3-,SO42-,and NH4+ in haze days were 6.5,3.9,and 5.3 times higher than those in normal days,respectively,while primary species(EC,Ca2+,K+) show similar increase from normal to haze days by a factor about 2.2-2.4.OC/EC ratio ranged from 2.8 to 6.2 with an average of 4.7 and the estimation on a minimum OC/EC ratio showed that SOC(secondary organic carbon) accounted more than 36.6% for the total organic carbon in haze days.The significantly increase in the secondary species(SOC,NO3-,SO42-,and NH4+),especially in NO3-,caused the worst air quality in this region.Simultaneously,the result illustrated that the serious air pollution in haze episodes was strongly correlated with the meteorological conditions.During the sampling periods,air pollution and visibility had a good relationship with the air mass transport distance;the shorter air masses transport distance,the worse air quality and visibility in Guangzhou,indicating the strong domination of local sources contributing to haze formation.High concentration of the secondary aerosol in haze episodes was likely due to the higher oxidation rates of sulfur and nitrogen species. | TAN Jihua DUAN Jingchun HE Kebin MA Yongliang DUAN Fengkui CHEN Yuan FU Jiamo | 2009 | Journal of Environmental Sciences2009，21，6： | 71 |
| 2 | Air pollution characteristics and their relationship with emissions and meteorology in the Yangtze River Delta region during 2014–2016显示文摘With rapid economic growth and urbanization, the Yangtze River Delta(YRD) region in China has experienced serious air pollution challenges. In this study, we analyzed the air pollution characteristics and their relationship with emissions and meteorology in the YRD region during 2014–2016. In recent years, the concentrations of all air pollutants, except O3,decreased. Spatially, the PM2.5, PM10, SO2, and CO concentrations were higher in the northern YRD region, and NO2 and O3 were higher in the central YRD region. Based on the number of non-attainment days(i.e., days with air quality index greater than 100), PM2.5 was the largest contributor to air pollution in the YRD region, followed by O3, PM10, and NO2.However, particulate matter pollution has declined gradually, while O3 pollution worsened.Meteorological conditions mainly influenced day-to-day variations in pollutant concentrations. PM2.5 concentration was inversely related to wind speed, while O3 concentration was positively correlated with temperature and negatively correlated with relative humidity.The air quality improvement in recent years was mainly attributed to emission reductions.During 2014–2016, PM2.5, PM10, SO2, NOx, CO, NH3, and volatile organic compound(VOC)emissions in the YRD region were reduced by 26.3%, 29.2%, 32.4%, 8.1%, 15.9%, 4.5%, and0.3%, respectively. Regional transport also contributed to the air pollution. During regional haze periods, pollutants from North China and East China aggravated the pollution in the YRD region. Our findings suggest that emission reduction and regional joint prevention and control helped to improve the air quality in the YRD region. | Tao Ma Fengkui Duan Kebin He Yu Qin Dan Tong Guannan Geng Xuyan Liu Hui Li Shuo Yang Siqi Ye Beiyao Xu Qiang Zhang Yongliang Ma | 2019 | Journal of Environmental Sciences2019，31，9： | 26 |
| 3 | Metal Flowing of Involute Spline Cold Roll-beating Forming显示文摘The present research on involute spline cold roll-beating forming is mainly about the principles and motion relations of cold roll-beating,the theory of roller design,and the stress and strain field analysis of cold roll-beating,etc.However,the research on law of metal flow in the forming process of involute spline cold roll-beating is rare.According to the principle of involute spline cold roll-beating,the contact model between the rollers and the spline shaft blank in the process of cold roll-beating forming is established,and the theoretical analysis of metal flow in the cold roll-beating deforming region is proceeded.A finite element model of the spline cold roll-beating process is established,the formation mechanism of the involute spline tooth profile in cold roll-beating forming process is studied,and the node flow tracks of the deformation area are analyzed.The experimental research on the metal flow of cold roll-beating spline is conducted,and the metallographic structure variation,grain characteristics and metal flow line of the different tooth profile area are analyzed.The experimental results show that the particle flow directions of the deformable bodies in cold roll-beating deformation area are determined by the minimum moving resistance.There are five types of metal flow rules of the deforming region in the process of cold roll-beating forming.The characteristics of involute spline cold roll-beating forming are given,and the forming mechanism of involute spline cold roll-beating is revealed.This paper researches the law of metal flow in the forming process of involute spline cold roll-beating,which provides theoretical supports for solving the tooth profile forming quality problem. | CUI Fengkui WANG Xiaoqiang ZHANG Fengshou XU Hongyu QUAN Jianhui LI Yan | 2013 | Chinese Journal of Mechanical Engineering2013，26，5： | 19 |
| 4 | Characteristics and source identification of fine particulate n-alkanes in Beijing, China显示文摘Ambient particulate n-alkanes were determined for fine particle (PM2.5) samples collected from Sep 2003 to July 2004 in Beijing, China. The average concentration of total n-alkanes ( n-alkanes) from C11 to C34 was 425.72 ng/m3, ranged from 7.02 to 2893.28 ng/m3. The concentration distributions of n-alkanes homologues in this study exhibited peaks at C21 and C29 in heating season, and C29 in non-heating season. The average carbon preference index (CPI) value was 1.88 in the range of 1.18-3.88. The maximum CPI in summer indicated the contribution of biogenic origins such as plant wax; while the minimum CPI value in winter was probably a result of fossil fuel combustion. Preliminary estimation from these results showed that 59% of the n-alkanes in PM2.5 in Beijing summer originated from plant wax, while 74%-88% was from fossil fuel combustion in other three seasons. Source estimation was further performed using principal component analysis method. Two major components were yielded accounting for 57.3% and 30.9% of the total variance, which presented the fossil fuel and biogenic contribution, respectively. | Fengkui Duan Kebin He Xiande Liu | 2010 | Journal of Environmental Sciences2010，22，7： | 11 |
| 5 | Physicochemical analysis of individual atmospheric fine particles based on effective surface-enhanced Raman spectroscopy显示文摘Fine particles associated with haze pollution threaten the health of more than 400 million people in China. It is therefore of great importance to thoroughly investigate and understand their composition. To determine the physicochemical properties in atmospheric fine particles at the micrometer level, we described a sensitive and feasible surface-enhanced Raman scattering(SERS) method using Ag foil as a substrate. This novel method enhanced the Raman signal intensities up to 10,000 a.u. for ν(NO_3^-) in fine particles.The SERS effect of Ag foil was further studied experimentally and theoretically and found to have an enhancement factor of the order of ~10~4. Size-fractionated real particle samples with aerodynamic diameters of 0.4–2.5 μm were successfully collected on a heavy haze day,allowing ready observation of morphology and identification of chemical components, such as soot, nitrates, and sulfates. These results suggest that the Ag-foil-based SERS technique can be effectively used to determine the microscopic characteristics of individual fine particles, which will help to understand haze formation mechanisms and formulate governance policies. | Zhenli Sun Fengkui Duan Kebin He Jingjing Du Liu Yang Hui Li Tao Ma Shuo Yang | 2019 | Journal of Environmental Sciences2019，31，1： | 9 |
| 6 | Spatio-temporal characteristics of cultivated land fragmentation in different landform areas with a case study in Northeast China显示文摘Assessing the temporal and spatial characteristics of cultivated land fragmentation is necessary to identify management practices that can reduce negative environmental effects.Thus,the purpose of this study was to use principal component analysis and spatial autocorrelation to analyze the dynamic characteristics of cultivated land fragmentation in different landform areas in Liaoning Province,China,in terms of time and space.An additional objective was to match the changes with the natural and social environment to support the sustainable development of fragmented cultivated land.The results indicated that the evolutionary trends of cultivated land fragmentation in the central plain area showed a weakening trend,contrary to those observed in the western hilly and eastern mountainous areas.Moreover,the spatial distribution characteristics of cultivated land fragmentation in the western hilly area were generally“external low,internal high,”primarily because of the edge density of cultivated land patches.The spatial distribution characteristics of cultivated land fragmentation in the central plain area were generally“external high,internal low,”primarily because of the number and division of cultivated land patches.The spatial distribution characteristics of cultivated land fragmentation in the eastern mountainous area were generally“south low,north high”because of the division of cultivated land patches.These results can provide guidelines for planners,managers,decision-makers and others to formulate regulatory policies,identify land remediation areas,and promote the sustainable development of cultivated land. | Fengkui Qian Yanru Chi Rattan Lal Klaus Lorenz | 2020 | Ecosystem Health and Sustainability2020，6，1： | 6 |
| 7 | Ambient Backscatter Communications over NOMA Downlink Channels显示文摘In this paper,we investigate the performance of commensal ambient backscatter communications(AmBC)that ride on a non-ortho go nal multiple access(NOMA)downlink transmission,in which a backscatter device(BD)splits part of its received signals from the base station(BS)for energy harvesting,and backscatters the remaining received signals to transmit information to a cellular user.Specifically,under the power consumption constraint at BD and the peak transmit power constraint at BS,we derive the optimal reflection coefficient at BD,the optimal total transmit power at BS,and the optimal power allocation at BS for each transmission block to maximize the ergodic capacity of the ambient backscatter transmission on the premise of preserving the outage performance of the NOMA downlink transmission.Furthermore,we consider a scenario where the BS is restricted by a maximum allowed average transmit power and the reflection coefficient at BD is fixed due to BD’s low-complexity nature.An algorithm is developed to determine the optimal total transmit power and power allocation at BS for this scenario.Also,a low-complexity algorithm is proposed for this scenario to reduce the computational complexity and the signaling overheads.Finally,the performance of the derived solutions are studied and compared via numerical simulations. | Weiyu Chen Haiyang Ding Shilian Wang Daniel Benevides daCosta Fengkui Gong Pedro Henrique Juliano Nardelli | 2020 | China Communications2020，17，6： | 4 |
| 8 | Bimetallic amine-bridged bis(phenolate) lanthanide aryloxides and alkoxides: synthesis, characterization, and application in the ring-opening polymerization of rac-lactide and rac-β-butyrolactone显示文摘A series of neutral bimetallic lanthanide aryloxides p-C6H4[OLnL(THF)n]2 [Ln = Y(1), Yb(2), Sm(3)(n = 1) and La(4)(n = 2), L = Me2NCH2CH2N{CH2-(2-O–C6H2–tBu2-3,5)}2] and alkoxides p-C6H4CH2[OLnL(THF)]2 [Ln = Y(5), Yb(6)] supported by an amine-bridged bis(phenolate) ligand have been synthesized through one-pot reactions of Ln(C5H5)3(THF), LH2 with p-benzenediol and 1,4-benzenedimethanol, respectively. All complexes have been fully characterized by elemental analyses, single-crystal X-ray diffraction analysis, and IR and multi-nuclear NMR spectroscopy(in the cases of 1, 4 and 5). Study of their catalytic behavior revealed that, in general, all complexes are efficient initiators for the polymerization of rac-lactide(LA) and rac-β-butyrolactone(BBL), except for 3 and 4 in the case of BBL. The influence imposed by lanthanides of different ionic radii and initiating groups of different structures on the activity, controllability, and stereoselectivity of polymerization were systematically studied and compared. Highly heterotactic PLA(Pr up to 0.99) and syndiotactic PHB(Pr ≈ 0.81) with high molecular weight and narrow polydispersity formed and were automatically capped with hydroxyl functionality at both ends. | NIE Kun FENG Tao SONG FengKui ZHANG Yong SUN HongMei YUAN Dan YAO YingMing SHEN Qi | 2014 | Science China Chemistry2014，57，8： | 3 |
| 9 | Characteristics of carbonaceous aerosols in Beijing, China显示文摘 | Fengkui Duan Kebin He Yongliang Ma Yingtao Jia Fumo Yang Yu Lei S. Tanaka T. Okuta | 2005 | Chemosphere2005，，3： | 3 |
| 10 | P-T stability conditions of methane hydrate in sediment from South China Sea显示文摘For reasonable assessment and safe exploitation of marine gas hydrate resource, it is important to determine the stability conditions of gas hydrates in marine sediment. In this paper, the seafloor water sample and sediment sample (saturated with pore water) from Shenhu Area of South China Sea were used to synthesize methane hydrates, and the stability conditions of methane hydrates were investigated by multi-step heating dissociation method. Preliminary experimental results show that the dissociation temperature of methane hydrate both in seafloor water and marine sediment, under any given pressure, is depressed by approximately -1.4 K relative to the pure water system. This phenomenon indicates that hydrate stability in marine sediment is mainly affected by pore water ions. | Shicai Sun Yuguang Ye Changling Liu Fengkui Xiang Yan Ma | 2011 | Journal of Natural Gas Chemistry2011，20，5： | 2 |
| 11 | Work Hardening Behavior of 1020 Steel During Cold-Beating Simulation显示文摘The present research of cold-beating formation mainly focused on roller design and manufacture, kinematics, constitutive relation, metal flow law, thermo-mechanical coupling, surface micro-topography and microstructure evolution. However, the research on surface quality and performance of workpieces in the process of cold-beating is rare. Cold-beating simulation experiment of 1020 steel is conducted at room temperature and strain rates ranging from 2000 to 4000 s^(-1) base on the law of plastic forming. According to the experimental data, the model of strain hardening of 1020 steel is established,Scanning Electron Microscopy(SEM) is conducted, the mechanism of the work hardening of 1020 steel is clarified by analyzing microstructure variation of 1020 steel. It is found that the strain rate hardening effect of 1020 steel is stronger than the softening effect induced by increasing temperatures, the process of simulation cold-beating cause the grain shape of 1020 steel significant change and microstructure elongate significantly to form a fibrous tissue parallel to the direction of deformation, the higher strain rate, the more obvious grain refinement and the more hardening effect. Additionally, the change law of the work hardening rate is investigated, the relationship between dislocation density and strain, the relationship between work hardening rate and dislocation density is obtained.Results show that the change trend of the work hardening rate of 1020 steel is divided into two stages, the work hardening rate decreases dramatically in the first stage and slowly decreases in the second stage, finally tending toward zero. Dislocation density increases with increasing strain and strain rate, work hardening rate decreases with increasing dislocation density. The research results provide the basis for solving the problem of improving the surface quality and performance of workpieces under cold-beating formation of 1020 steel. | Fengkui CUI Yuanfei LING Jinxue XUE Jia LIU Yuhui LIU Yan LI | 2017 | Chinese Journal of Mechanical Engineering2017，30，2： | 2 |
| 12 | 显示文摘 | Li Fengkui Zhu Wei Zhang Xian | 1999 | Journal of Applied Polymer Science1999，71，： | 2 |
| 13 | Surface-enhanced Raman scattering for mixing state characterization of individual fine particles during a haze episode in Beijing,China显示文摘The nondestructive characterization of the mixing state of individual fine particles using the traditional single particle analysis technique remains a challenge.In this study,fine particles were collected during haze events under different pollution levels from September 5 to 112017 in Beijing,China.A nondestructive surface-enhanced Raman scattering(SERS)technique was employed to investigate the morphology,chemical composition,and mixing state of the multiple components in the individual fine particles.Optical image and SERS spectral analysis results show that soot existing in the form of opaque material was predominant during clear periods(PM_(2.5)≤75μg/m^(3)).During polluted periods(PM_(2.5)>75μg/m^(3)),opaque particles mixed with transparent particles(nitrates and sulfates)were generally observed.Direct classical least squares analysis further identified the relative abundances of the three major components of the single particles:soot(69.18%),nitrates(28.71%),and sulfates(2.11%).A negative correlation was observed between the abundance of soot and the mass concentration of PM_(2.5).Furthermore,mapping analysis revealed that on hazy days,PM_(2.5)existed as a core-shell structure with soot surrounded by nitrates and sulfates.This mixing state analysis method for individual PM_(2.5)particles provides information regarding chemical composition and haze formation mechanisms,and has the potential to facilitate the formulation of haze prevention and control policies. | Hui Chen Fengkui Duan Jingjing Du Ranhao Yin Lidan Zhu Jinlu Dong Kebin He Zhenli Sun Suhua Wang | 2021 | Journal of Environmental Sciences2021，33，6： | 2 |
| 14 | A review on water in low rank coals: The existence, interaction with coal structure and effects on coal utilization显示文摘 | Jianglong Yu Arash Tahmasebi Yanna Han Fengkui Yin Xianchun Li | 2013 | Fuel Processing Technology2013，，： | 2 |
| 15 | Using Si depletion in aerosol to identify the sources of crustal dust in two Chinese megacities显示文摘 | Qing Zhao Kebin He Kenneth A. Rahn Yongliang Ma Fumo Yang Fengkui Duan | 2010 | Atmospheric Environment2010，，21： | 1 |
| 16 | Improved measurement of carbonaceous aerosol:evaluation of the sampling artifacts and inter-comparison of the thermal-optical analysis methods显示文摘 | CHENG Yuan HE Kebin DUAN Fengkui | 2010 | Atmospheric Chemistry and Physics2010，10，17： | 1 |
| 17 | Identification and estimate of biomass burning contribution to the urban aerosol organic carbon concentrations in Beijing显示文摘 | Duan Fengkui Liu Xiande Yu Tong | 2004 | Atmospheric Environment2004，38，9： | 1 |
| 18 | Thermosetting polymers from cationic copolymerization of tung oil: Synthesis and charac- terization显示文摘 | Li Fengkui Richard C Larock | 2000 | J Appl Polym Sci2000，78，5： | 1 |
| 19 | Sampling artifacts of organic and inorganic aerosol:Implications for the speciation measurement of particulate matter显示文摘 | CHENG Yuan DUAN Fengkui HE Kebin | 2012 | Atmospheric Environment2012，55，8： | 1 |
| 20 | Studies on thermally stimulated shape memory effect of segmented polyurethanes显示文摘 | Li Fengkui Zhang Xian Hou Jianan | 1997 | Journal of Applied Polymer Science1997，64，： | 1 |
您所在的机构暂未开通此部分的功能，请联系管理员