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Search Results: 1 - 10 of 120275 matches for " Yanping Wang "
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Study for System of Nonlinear Differential Equations with Riemann-Liouville Fractional Derivative  [PDF]
Yanping Zheng, Wenxia Wang
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.47A002
Abstract:

In this work, we study existence theorem of the initial value problem for the system of fractional differential equations \"\"where Dα denotes standard Riemann-Liouville fractional derivative, 0 < α < 1, \"\" \"\"and A  is a square matrix. At the same time, power-type estimate for them has been given.

Research on Urban Community Facilities Safety Governance—Based on the Overall Perspective  [PDF]
Yanping Liu, Zhixiang Yuan, Yong Wang
World Journal of Engineering and Technology (WJET) , 2017, DOI: 10.4236/wjet.2017.53B005
Abstract:
Community facilities accidents happen every year in many cities of China, which has been an important issue in academic circles. The purpose of this study is to suggest the direction of universal design for the prevention of community facilities accidents. In this paper, from the overall angle, the impact factors of the urban community service facilities safety were analyzed. Then, based on the integrated governance theory, from such aspects as engineering and non-engineering disaster reduction, the governance measures were explored.
Effect of Hub-Ratio on Performance of Asymmetric Dual-Rotor Small Axial Fan  [PDF]
Yongmin Wu, Yingzi Jin, Yuzhen Jin, Yanping Wang, Li Zhang
Open Journal of Fluid Dynamics (OJFD) , 2013, DOI: 10.4236/ojfd.2013.32A013
Abstract: Currently, domestic and abroad scholars put more attention on contra-rotating dual-rotor axial fan. But there is less scholars study on asymmetric dual-rotor small axial fan, which is one of the contra-rotating dual-rotor axial fans. Like axial fan, many factors have influence on the performance of the asymmetric dual-rotor small axial flow fan, such as the wheel hub ratio, blade shape, blade number, stagger angle and the tip clearance. Because wheel hub ratio has great impact on the performance of the fan, we choose the size of wheel hub ratio as a variable factor to study the model change. There is a different wheel hub ratio between front stage impeller and rear stage of asymmetric dual-rotor small axial fan, so it is very beneficial to select the greater wind area that the fan area of external diameter minuses the area occupied by the blades and the hub as front stage impeller. In this paper, the hub-ratio of front stage impeller is 0.72, and that of rear stage is 0.72, 0.67 and 0.62 respectively along with the front stage impeller. Three kinds of models with different hub ratio of rear stage are simulated using the CFD software and the static characteristics are obtained. Based on the experimental test results, the internal flow field of the asymmetric dual-rotor small axial fan is analyzed in detail, the impact trends of different hub-ratio on the performance of asymmetric dual-rotor small axial fan are obtained and the argument of structure optimization for dual-rotor small axial fan is provided.
Numerical Study on Internal Flow of Small Axial Flow Fan with Splitter Blades  [PDF]
Lifu Zhu, Yingzi Jin, Yanping Wang, Li Zhang, Yuzhen Jin
Open Journal of Fluid Dynamics (OJFD) , 2013, DOI: 10.4236/ojfd.2013.32A012
Abstract: The splitter blades are widely used in axial compressors and play an active role in the improvement of the overall performance of compressors. However, little research on the application of splitter blades to small axial flow fans is conducted. This paper designs a splitter blade small axial flow fan (model B) with a small axial flow fan as the prototype fan (model A) by adding short blades at the second half part of the passageway among long blades of model A. The steady simulation for the two models was conducted with the help of RNG k-ε turbulence model provided by software Fluent, and static characteristics and internal flow characteristics of the two models were compared and analyzed. Results show that splitter blades can improve the unsteady flow in the small flow rate region and also have a positive role to increase static pressure rise and efficiency in the higher flow rate region. The variation of static pressure gradient on the meridian plane in model B is well-distributed. The static pressure on the blade surface of model B distributes more uniformly. Splitter blades can suppress the secondary flow from pressure side to suction side in the leading edge because the pressure difference between suction side and pressure side in model B is generally lower than that of model A. And it also can restrain the vortex shedding and flow separation, and further it may be able to get the aerodynamic noise lower because static pressure gradient on the blade surface is well-distributed and the vortex shedding is not developed. Therefore, the performance of the fan with splitter blades is better than that of the prototype fan. The findings of this paper can be a basis for the design of high performance small axial flow fans.
Effect of Cellulase and Lactic Acid Bacteria on Fermentation Quality and Chemical Composition of Wheat Straw Silage  [PDF]
Kuikui Ni, Yanping Wang, Huili Pang, Yimin Cai
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.513201
Abstract:

The object of this study was to determine the effect of cellulase and lactic acid bacteria (LAB) on fermentation quality and chemical composition of wheat straw silage. Silages were prepared using a small-scale fermentation system and the moisture level was adjusted to 60% of fresh matter (FM) with deionized water. Treatments were designed as: control silage without additives, LAB inoculant Lactobacillus casei Z3-1 (1.0 × 106 cfu·g-1 of FM), commercial inoculant L. plantarum FG 1 (1.0 × 106 cfu·g-1 of FM), Z3-1 + cellulase and FG 1 + cellulase. The neutral detergent fiber (NDF), acid detergent fiber (ADF) and crude protein (CP) contents of the wheat straw prior to ensiling were 76.93%, 48.52% and 4.63% of dry matter (DM), respectively. After 30 days of fermentation, the silages treated with LAB and LAB + cellulase had a lower (P < 0.05) pH and higher (P < 0.05) lactic acid content than the control, and the coliform bacteria, yeast and mold were inhibited at the early stage of fermentation. Besides, silages treated with cellulase had lower (P < 0.05) values of ADF and NDF than the control. The results confirmed that the addition of cellulase and LAB contributed to improving the fermentation quality of wheat straw silage.

Cloud Security: Services, Risks, and a Case Study on Amazon Cloud Services  [PDF]
Patrick Mosca, Yanping Zhang, Zhifeng Xiao, Yun Wang
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2014, DOI: 10.4236/ijcns.2014.712053
Abstract: Recent advances have witnessed the success and popularity of cloud computing, which represents a new business model and computing paradigm. The feature of on-demand provisioning of computational, storage, and bandwidth resources has driven modern businesses into cloud services. The cloud is considered cutting edge technology and it is solely relied on by many large technology, business, and media companies such as Netflix or Salesforce.com. However, in addition to the benefit at hand, security issues have been a long-term concern for cloud computing and are the main barriers of the widespread use of cloud computing. In this paper, we briefly describe some basic security concerns that are of particular interest to cloud technology. We investigate some of the basic cloud concepts and discuss cloud security issues. Amazon Web Services is used as a case study for discussing common cloud terminology. Data security, as well as some cloud specific attacks is introduced. The current state and the future progression of cloud computing is discussed.
Artificial Seeding Effects of Convective Clouds on the Opening Day of Beijing 2008 Summer Olympics  [PDF]
Hongyu Li, Yanping Dai, Hua Wang, Jingang Cui
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.54010
Abstract: Using the radar reflectivity and intensive rainfall data, artificial seeding effects of convective clouds in Beijing on 8 August 2008, the opening day of the 29th Summer Olympics, were analyzed. The results indicate that, cloud seeding at single operation site for convective clouds invading from southwest direction may sharply mitigate the rainfall observed at leeward automatic weather stations within 5 - 10 min, while enhances the precipitation at a later stage about 10 - 20 min. Cloud seeding effects of operation sites Yuegezhuangxi, Changgouzhen, and Zhoukou, which are placed along the main moving routes or localized developing convective clouds in the west and center parts of Fangshan district, are very conspicuous. Combining the operation sites distribution and radar echoes, it is found that the site Changgouzhen, which is very close to the convective core, plays an essential role in suppressing the growth of convective cloud, reducing the coverage area of intense echoes classified as 45 - 60 dBZ, as well as mitigating the precipitation from neighboring automatic weather stations. Based on radar reflectivity and rainfall data, we find that the clouds over lots of operation sites in eastern Fangshan district are not cold enough to favor glaciogenic seeding with silver iodide, meanwhile, there is not too much precipitation observed.
Nestedness of snake assemblages on islands of an inundated lake
Yanping WANG, Xi WANG, Ping DING
Current Zoology , 2012,
Abstract: Nestedness is a pattern frequently reported for faunal assemblages in fragmented systems. Although nestedness has been documented for a wide range of taxa, it is rarely tested in snake assemblages. To arrive at robust generalizations about proce-sses and mechanisms structuring island biotas, it is important to examine under-represented taxa such as snakes for the insights they may offer. We tested for the existence of nestedness and underlying causal mechanisms using snake data collected on islands in the Thousand Island Lake, China. We used the line-transect method to survey snake occupancy and abundance on 20 islands during two breeding seasons in 2009 and 2010. We used the recently developed metric WNODF to estimate nestedness. We used Spearman rank correlations to examine the associations of nestedness and habitat variables (area, isolation, and habitat diversity) as well as life-history traits (body size, clutch size, geographical range size and area requirement) related to species extinction and immigration tendencies. Snake assemblages were significantly nested and were shaped by extinction processes mediated through area effects and habitat nestedness. The nestedness of snake assemblages was not due to passive sampling or selective colonization. From a conservation viewpoint, our results indicate that we should protect both the largest island with the most species-rich community and habitat-rich islands to maximize the number of species preserved [Current Zoology 58 (6): 828–836, 2012].
ADSL, AMPD1, and ATIC Expression Levels in Muscle and Their Correlations with Muscle Inosine Monophosphate Content in Dapulian and Hybridized Pig Species  [PDF]
Rongsheng Zhu, Yanping Wang, Huaizhong Wang, Song Lin, Shouli Sun, Baohua Huang, Hongmei Hu
Open Journal of Animal Sciences (OJAS) , 2017, DOI: 10.4236/ojas.2017.74030
Abstract: We investigated the relationship between muscle inosine monophosphate (IMP) content and mRNA levels of ADSL, AMPD1, and ATIC in Dapulian (DPL), Landrace × Dapulian (LDPL), and Duroc × Landrace × Dapulian (DLDPL) hybridized pigs. Methods: The total RNA in longissimus dorsi was isolated from Dapulian (DPL), Landrace × Dapulian (LDPL) and Duroc × Landrace × Dapulian (DLDPL) hybridized pigs, weighed about 95.0 kg, n = 8/species. The internal genes with highest stability (YWHAZ and RPL4) were chosen from 11 common internal genes using Quantitative real-time PCR (qPCR) and geNorm software. The mRNA levels of ADSL, AMPD1 and ATIC genes were corrected with YWHAZ and RPL4 genes. The muscular IMP content was determined by HPLC. The muscular IMP content in DPL was higher than that in LDPL and DLDPL, 25.00% (p < 0.05) and 15.56% (p > 0.05), respectively. The muscular mRNA level of ADSL gene in DPL and LDPL was higher than that in DLDPL, 24.14% and 12.07%, respectively (p < 0.05). The muscular mRNA level of ATIC gene in DPL and LDPL was higher than that in DLDPL, 66.67% and 33.33%, respectively (p < 0.05). The muscular mRNA level of AMPD1 gene in DPL and LDPL was higher than that in DLDPL, 14.49% and 33.26%, respectively. Furthermore, the IMP content was
Surface chemical structure of titania-silica nanocomposite powder
LuYan Wang,YanPing Sun,BingShe Xu
Chinese Science Bulletin , 2008, DOI: 10.1007/s11434-008-0427-x
Abstract: Titania-silica (TS) nanocomposite powder with three different composite structures, containing 10–30 mol% SiO2 in each structure, have been prepared by sol-gel processes. The surface characteristics of these titania-silica samples have been investigated by X-ray photo-emission spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM). The study for all TS oxides annealed at 773 and 1173 K showed: an abnormal surface enrichment in Si increased with increasing annealing temperature; the Ti3+, Ti2+, Si3+ and Si2+ oxides coexisted with Ti4+ and Si4+ oxides, and the contents of these Ti/Si suboxides increased with increasing SiO2 content and annealing temperature; there was a layerrich in O on the topmost surface and the excess O could be attributed to the chem-adsorption of H2O; different composite structures could lead to different contents of Ti/Si suboxides. These results indicated that the surface of TS oxide powder derived by sol-gel process was a double layer with enriched O first and then SiOx/TiO y (x, y<2). Ti/Si suboxides could result from the thermal diffusion of Ti4+ and Si4+, which might be induced by the strong interaction between Ti4+ and Si4+.
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