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Search Results: 1 - 10 of 12418 matches for " Wenjun Xie "
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Analysis of Air Pollutants in Xiong’an New Area Based on MATLAB Grey Model  [PDF]
Ying Xie, Wenjun Wang, Baochang Li, Zhiwei Zhao, Lei He
Open Journal of Air Pollution (OJAP) , 2018, DOI: 10.4236/ojap.2018.74015
Abstract: The purpose of this paper is to study the air pollutants in Xiong’an New Area based on MATLAB grey model [1]. From 2011 to 2016, the results of sulfur dioxide (SO2), nitrogen dioxide (NO2) and inhalable particulate matter (PM1O) detected at monitoring points in the three counties of Xiong’an were analyzed. According to the national environmental air quality standard [2], the air quality in Xiong’an New Area was reasonably evaluated based on grey model in MATLAB. Judging from the weight of pollution factors in the model, sulfur dioxide (SO2) is the controlling factor of air quality in Xiong’an New Area, and the weight of nitrogen dioxide (NO2) gradually increases. The main sources of the three pollutants were obtained by comprehensive data analysis, and a grey model was established according to the mass concentration of the main air pollutants, and the grey forecasting model was tested. The experimental results show that the model can be effectively applied to the forecasting of ambient air quality. On this basis, the present situation of atmospheric environmental quality in Xiong’an New Area and suggestions for improvement are obtained.
Preparation and properties of copper-oil-based nanofluids
Li Dan,Xie Wenjie,Fang Wenjun
Nanoscale Research Letters , 2011,
Abstract: In this study, the lipophilic Cu nanoparticles were synthesized by surface modification method to improve their dispersion stability in hydrophobic organic media. The oil-based nanofluids were prepared with the lipophilic Cu nanoparticles. The transport properties, viscosity, and thermal conductivity of the nanofluids have been measured. The viscosities and thermal conductivities of the nanofluids with the surface-modified nanoparticles have higher values than the base fluids do. The composition has more significant effects on the thermal conductivity than on the viscosity. It is valuable to prepare an appropriate oil-based nanofluid for enhancing the heat-transfer capacity of a hydrophobic system. The effects of adding Cu nanoparticles on the thermal oxidation stability of the fluids were investigated by measuring the hydroperoxide concentration in the Cu/kerosene nanofluids. The hydroperoxide concentrations are observed to be clearly lower in the Cu nanofluids than in their base fluids. Appropriate amounts of metal nanoparticles added in a hydrocarbon fuel can enhance the thermal oxidation stability.
Adsorption Properties of Gemini and Monomeric Cationic Surfactants on Sandstone and Silica Nanoparticles  [PDF]
Wenjun Xie, Ge Xu, Yancheng Zheng, Shining Chen, Zhuo Yang, Borui Li
Open Journal of Yangtze Oil and Gas (OJOGas) , 2018, DOI: 10.4236/ojogas.2018.33018
Abstract: The surface modification of pore throat by adsorption of surfactants is thought to have a positive effect on water flooding in low and ultralow permeability reservoirs. In this paper, Gemini cationic surfactants, containing 12 and 16 carbon alkyl chains(ethanediyl-1,2-bis(dimethyl dodecyl ammonium bromide) and ethanediyl-1,2-bis(dimethyl cetyl ammonium bromide), referred to as GC12 and GC16) and hexadecyl trimethyl ammonium bromide (CTAB) were used as modifying agents to investigate the effects of the surfactant concentration, adsorption time and temperature on static adsorption onto the surface of sandstone and silica nano particles (NPS). The results show that the equilibrium adsorption amount of GC16 on sandstone and NPS is higher than that of GC12 on sandstone and NPS with the same initial concentration of 0.225 mmol/L in solution at 45°C. It is found that the adsorption amounts of GC12 and GC16 decrease as the raise of temperature. The adsorption rate of surfactant on sandstone surface is slower than that of NPS. The equilibrium adsorption time of these surfactants on sandstone is 20 h, while the time of NPS is only 2 h. At 55°C, the static saturation absorption amount of GC12 is 210.56 μmol/g on NPS and 117.67 μmol/g on sandstone, while the amounts of CTAB on sandstone and NPS under static conditions are 1.18 times and 1.46 times of GC12, respectively. Considering the number of tail chain in a molecule of surfactant, the packing densities of Gemini surfactants on solid surface are higher than that of the single-tail surfactant (CTAB). Therefore, the adsorption rate and amount of surfactant are affected by the specific surface of solid particles, charged density, tail chain number and length of the cationic group.
The Line Clipping Algorithm Basing on Affine Transformation  [PDF]
Wenjun Huang
Intelligent Information Management (IIM) , 2010, DOI: 10.4236/iim.2010.26046
Abstract: A new algorithm for clipping line segments by a rectangular window on rectangular coordinate system is presented in this paper. The algorithm is very different to the other line clipping algorithms. For the line segments that cannot be identified as completely inside or outside the window by simple testings, this algorithm applies affine transformations (the shearing transformations) to the line segments and the window, and changes the slopes of the line segments and the shape of the window. Thus, it is clear for the line segment to be outside or inside of the window. If the line segments intersect the window, the algorithm immediately (no solving equations) gets the intersection points. Having applied the inverse transformations to the intersection points, the algorithm has the final results. The algorithm is successful to avoid the complex classifications and computations. Besides, the algorithm is effective to simplify the processes of finding the intersection points. Comparing to some classical algorithms, the algorithm of this paper is faster for clipping line segments and more efficient for calculations.
Integrated Web Architecture Based on Web3D, Flex and SSH  [PDF]
Wenjun ZHANG
Journal of Software Engineering and Applications (JSEA) , 2010, DOI: 10.4236/jsea.2010.31009
Abstract: Focusing on the problems occurred in traditional 2D image-word-based web applications, the author put forward con-cept of integrating Web3D, Flex and SSH technologies to create advanced “3D Virtual Reality & RIA” web application architecture, researched mechanisms of their architectures, and implemented their integration and communication & interaction: Flex and Struts2 via XML, Flex and Spring & Hibernate via BlazeDS, Flex and Web3D via JavaScript. The practice has shown that the integrated web architecture based on Web3D, Flex and SSH is effective and valuable.
The liquid phase separation of Bi-Ga hypermonotectic alloy under acoustic levitation condition
ZhenYu Hong,YongJun Lü,WenJun Xie,BingBo Wei
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0231-z
Abstract: Containerless treatment of Bi-58.5at%Ga hypermonotectic alloy is successfully performed with acoustic levitation technique. Under acoustic levitation condition, the second phase (Ga) distributes almost homogeneously in solidification sample, opposite to macrosegregation in solidification sample under conventional condition. Stokes motion of the second liquid droplet (Ga) is significantly restrained under acoustic levitation condition. The analyses indicate that the melt vibration in the gravity direction forced by acoustic field can induce steady flow around the second liquid droplet, which influences droplet shape during its moving upward and consequently restrains Stokes motion velocity of the second liquid droplet.
Containerless processing by single-axis electrostatic levitation
Liang Hu,HaiPeng Wang,WenJun Xie,BingBo Wei
Chinese Science Bulletin , 2010, DOI: 10.1007/s11434-010-9984-x
Abstract:
Freestanding single-walled carbon nanotube bundle networks: Fabrication, properties and composites
WeiYa Zhou,WenJun Ma,ZhiQiang Niu,Li Song,SiShen Xie
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-011-4878-0
Abstract: As a type of thin film, two dimensional (2D) reticulate architectures built of freestanding single-walled carbon nanotube (SWCNT) bundles are suitable for scalable integration into devices and nanocomposites for many applications. The superior properties of these films, such as optical transparency, unique electrical properties and mechanical flexibility, result not only from the outstanding properties of individual SWCNTs but also from the collective behavior of the individual tubes, with additional properties arising from the tube-tube interactions. In this review, the synthesis, structure and fundamental properties, such as conductivity, transparency, optical nonlinearity and mechanical performance, of “freestanding SWCNT bundle network” thin films and nanocomposites, as well as their application as supercapacitors are highlighted. Some long-standing problems and topics warranting further investigation in the near future are addressed.
Dynamic solidification of Sn-38.1% Pb eutectic alloy within ultrasonic field
Wei Zhai,ZhenYu Hong,WenJun Xie,BingBo Wei
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-010-4084-5
Abstract: The dynamic solidification of Sn-38.1% Pb eutectic alloy within an ultrasonic field is investigated at a frequency of 35 kHz. As the sample height H is reduced, the effect of ultrasound on macrosegregation becomes more prominent, and the volume fraction of spherical eutectic cells increases correspondingly. When H equals the wavelength λ in liquid alloy, the introduction of ultrasound enlarges the distribution region of the primary (Sn) phase, but reduces the domains of the Sn-Pb eutectic and primary (Pb) phases. Meanwhile, a “dendritic-equiaxed” structural transition occurs in the primary (Sn) phase, and its grain size is significantly reduced within the ultrasonic field. Once H decreases to λ/2 and λ/4, the ultrasonic field promotes crystal nucleation and suppresses further undercooling of the bulk liquid alloy. Theoretical analyses indicate that the local high pressure induced by the cavitation effect and the stirring effect due to acoustic streaming are the main factors dominating the eutectic growth mechanism during dynamic solidification.
Solidification characteristics of Pb-Sb hypereutectic alloy within ultrasonic field
Wei Zhai,ZhenYu Hong,WenJun Xie,BingBo Wei
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0077-4
Abstract: The solidification of Pb-16%Sb hypereutectic alloy is investigated within ultrasonic field with a frequency of 15 kHz. It is found that the ultrasonic field promotes crystal nucleation and terminates the further bulk undercooling of the alloy melt. Theoretical analysis shows that the cavitation effect and the forced bulk vibration are the main factors that reduce the undercooling level. With the increase of ultrasound intensity, the primary (Sb) phase experiences a growth mode transition from faceted to non-faceted branched growth, and the macrosegregation of primary (Sb) phase is gradually suppressed. In addition, the microstructures of Pb-Sb eutectic exhibit a conspicuous coarsening with increasing ultrasound intensity, and a structural transition of “lamellar eutectic—anomalous eutectic” occurs when ultrasound intensity rises up to 1.6 W/cm2. The ultrasonic field also changes the solute distribution adjacent to the solidification front, which lowers the Pb contents in primary (Sb) phase.
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