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Search Results: 1 - 10 of 2282 matches for " Yafeng Nie "
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The Effect of a Cerous Complex on Anti-Corrosion Characteristic of Bonded Film Containing Graphite

Lian Yafeng,Nie Mingde,Dang Hongxin,

摩擦学学报 , 1994,
Abstract: A certain tatio of graphite was added to bonded MoS2 solid film because of a synergisticeffect of tribological properties of graphite with molybdenum disulfide,but graphite may acceleratethe corrosion of metal substrate and exacerbate the corrosion resistance of bonded film,Formolybdenum disulfide-graphite bonded film,factors causing corrosion were investigated in thispaper. Various anti-corrosion additives(inhibitors),which were used to improve the corrosionresistance of bonded film,were also mentioned. In order to improve the corrosion resistance ofbonded film containing graphite,a cerous complex(BuC)of di-n-butylphosphinic acid with cerousnitrate was added to novolac-epoxy-MoS2 bonded film. The salt(NaCl)spray corrosion tester wasused to determine the effects of different additives on the corrosion resistance of bonded film. Thecorrosion test was carried out in accordance with ANSI/ASTM B117-73(1979).The test resultsshow that the bonded films containing di-n-butylphosphinic acid(BuP),CeF3,Sb2O3 separately orwithout these additives were all corroded after 150 hours continuous corrosion test, however,thebonded film containing BuC was not corroded after more than 500 hours continuous corrosion test.BuP can not be as an anti-corrosion additive for the bonded film and it has a short time of apperancerust dot. The results of XPS show that theaddition of BuC is effective to reduce the oxidation degreeof MoS2 in the film. The distribution of BuC in bonded film is uniform,i.e. it has high content ofBuC at the surface and interfdce,and low content in the inner laver of bonded film. The oxidationdegree of MoS2 in defferent layer of bonded film is different.Considering these results,we mayconclude that the increasing of corrosion resistance of bonded film containing graphite is due to thedistribution of BuC in bonded film and its adsorption on MoS2.
Sidelobe Suppression in CR-OFDM system by Adding Extended Data Carriers  [PDF]
Tianwei Wen, Yafeng Wang
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.53B2060
Abstract: Out-band radiation is a severe problem for Cognitive Radio with OFDM system (CR-OFDM) which is caused by the sidelobe of OFDM signals. Lots of studies have been done on suppressing the sidelobe power and numerous methods have been proposed. In this paper, we propose a novel method to minimize the sidelobe by adding extended data carrier so called EDC to the original data carriers so as to protect primary user (PU) spectrum. Unlike the methods before, the EDCs are deployed within the secondary user (SU) data frequency spectrum to fully use the spectrum. Moreover, we derive the linear least squares problem to get the optimal weighting factors of EDCs to minimize the sidelobe power which is subject to an original data interference constraint. By simulation, we find that EDC is more capable in sidelobe suppression than method of Cancellation Carrier (CC) while EDC has only a small loss in BER performance.
Emissions of Biogenic Sulfur Gases from Wheat Fields

Nie Yafeng,Zhang Jinhu,Xi Shuqi,Yang Zhen,

环境科学 , 2001,
Abstract: Emission rates of carbonyl sulfide (COS), carbon disulfide (CS2) and dimethyl sulfide (DMS) to the atmosphere from wheat fields treated with different fertilizers were measured by using the closed chamber method. The results showed that the emission rate of COS, CS2 and DMS was affected by wheat growth and COS was absorbed by the plants. DMS and CS2 were the predominant sulfur gases emitted from these fields. The diurnal variations of emission rates of COS and CS2 were obvious. The sulfur flux in the plot treated with organic fertilizer was higher than that in the other plots. The sulfur fluxes from different plots were in the range of -1.40 to 0.79 mg·m-2.
Behavior and fate of endocrine disrupting chemicals inmunicipal sewage treatment plants: A review

NIE Yafeng,QIANG Zhimin,ZHANG Heqing,BEN Weiwei,

环境科学学报 , 2011,
Abstract: Endocrine disrupting chemicals (EDCs), as a class of emerging contaminants, have raised worldwide concern due to their potential disrupting effects on the endocrine system of wild animals even at trace levels in the aquatic environment. This paper reviews the occurrence and removal efficiency of two groups of typical EDCs (i.e., steroid estrogens and phenolic EDCs) in municipal sewage treatment plants, and particularly discusses the effects of different biological treatment processes as well as operational parameters on their removal efficiency. Further, through examining the adsorption and biodegradation characteristics of EDCs, the possible removal mechanisms of EDCs in the activated sludge process are proposed.
Rapid Detection of Milk Protein based on Proteolysis Catalyzed by Trypsinase
Yafeng Chen
Modern Applied Science , 2011, DOI: 10.5539/mas.v5n2p82
Abstract: Using pH-state method, when degree of casein hydrolysis was set as criterion, the optimal enzymatic reaction conditions were obtained as follows: pH 7.5 and temperature 55 ?. Based on the proteolysis catalyzed by trypsinase, the relationship between protein content (x) and initial velocity of enzymatic reaction (y) was discussed and the equation of y=0.1177x (R2=0.9927)was found as standard curve for the calculation of protein content. In addition, the protein contents in five kinds of commercial fresh milk were determined by enzyme hydrolysis method and GB method (biuret method). Protein content calculated by enzyme hydrolysis method could be confirmed by GB method and the analysis of t-test indicated that there was no notable difference between two methods. Furthermore, the determinate time of the rapid method was only 8 minutes (including samples’ preparation) and was 1/20 times than that of biuret method.
Performance of HARQ in Device-to-Device Communication  [PDF]
Wenji Feng, Yafeng Wang, Lei Yang
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.53B2061
Abstract: In this paper, we study D2D (Device-to-Device) communication underlying LTE-Advanced uplink system. Since D2D communication reuses uplink resources with cellular communication in this scenario, it’s hard for D2D users to avoid the interference from cellular users while cellular users are communication with eNB (evolved Node B). HARQ (Hybrid Automatic Repeat reQuest) is widely used in LTE-Advanced system in order to improve the accurate rate of cellular communication. Hence, we consider studying the integration of D2D with HARQ, so as to achieve the purpose of improving the throughput of D2D communication and the performance of overall system. Synchronous HARQ is considered to introduce into D2D communication procedures. What’s more, this idea will be taken into system-level simulation. From the simulation results, we can see that the throughput of D2D communication gets a lot of gain and the performance of overall system is improved as well. In addition, Synchronous HARQ technique can significantly decrease the BLER (Block Error Rate) of D2D communication, especially for which in a bad channel condition.
Resource Allocation Method of Device-to-Device Communication  [PDF]
Wenji Feng, Yafeng Wang, Lei Yang
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.53B2062
Abstract: In this paper, we study D2D (Device-to-Device) communication underlying LTE-Advanced uplink system. Since D2D communication reuses uplink resources with cellular communication in this scenario, it’s hard to avoid the inference between D2D users and cellular users. If there is no restriction for D2D communication on using the whole uplink frequency band, it will have a strong negative impact on cellular communication. In order to overcome this shortage, we propose a resource allocation method that D2D users and cellular users use orthogonal frequency resources. This method will effectively reduce the inference between both kinds of communication. However, an obvious disadvantage of this method is no effective use of uplink resources. Based on this, we propose an optimized resource allocation method that a specific cellular user will be chosen to reuse the RBs (Resource Block) of D2D users. These ideas will be taken into system-level simulation, and from the results of simulation we can see that the optimized method has the ability to improve overall system performance and limit inference for cell-edge users.
Analysis of Relay Deployment Based on Handover Outage Probability in High Speed Scenarios  [PDF]
Liang Jing, Xiaojie Xu, Yafeng Wang
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.53B2063
Abstract: The LTE and LTE-Advanced systems are supposed to be the most popular cellular network in 4Gnetworks. Relay technology is one of the most preferred technologies proposed in LTE-Advanced standardization to improve the capacity and coverage. This paper analyses the handover outage probability through relay deployment, and proposes some proofs and suggestions for relay deployment to minimize the handover outage probability in high speed scenarios.
Comprehensive Research on the Origin of the Solar System Structure by Quantum-like Model  [PDF]
Qingxiang Nie
International Journal of Astronomy and Astrophysics (IJAA) , 2011, DOI: 10.4236/ijaa.2011.12008
Abstract: A quantum-like model of gravitational system is introduced to explore the formation of the solar system structure. In this model, the chaos behavior of a large number of original nebular particles in a gravitational field can be described in terms of the wave function satisfying formal Schrödinger equation, in which the Planck constant is replaced by a constant on cosmic scale. Numerical calculation shows that the radial distribution density of the particles has the character of wave curves with decreasing amplitudes and elongating wavelengths. By means of this model, many questions of the solar system, such as the planetary distance, mass, energy, angular momentum, the distribution of satellites, the structure of the planetary rings, and the asteroid belt and the Kuiper belt etc., can be explained in reason. In addition, the abnormal rotations of Venus and Mercury can be naturally explained by means of the quantum-like model.
A Study on the Second-Person Narrative in Jennifer Egan’s Black Box  [PDF]
Baoyu Nie
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.310008
Abstract: Notable for the second-person Twitter narrative, Jennifer Egan’s 2012 short science fiction Black Box is one of the most triumphant and fully-fledged fictions written in the form of new media. This paper mainly explores the second-person narrative employed in Black Box, pointing out that the second-person narrative leads the reader to participate in the story, allowing the reader to sense the same feelings as the protagonist does. From the second person’s perspective, Egan expresses her concerns and worries about the security of the American security as well as the whole world in the post-”9·11” period and at the same time she embraces the virtues and pleasures of traditional storytelling delivered through a wholly new digital format. This paper concludes that Black Box is perhaps one of the boldest experiments of narrative form and it is a direct exploration into the contemporary image culture.
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