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Search Results: 1 - 10 of 53602 matches for " Feng Yuan "
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Internet and Economic Growth—Evidence from Chinese Provincial Panel Data  [PDF]
Yuan Feng
Modern Economy (ME) , 2016, DOI: 10.4236/me.2016.78089
Abstract: As the “Internet +” strategy having been put forward, the internet and other information and communication technologies will help play more important role in Chinese economic growth. This research uses Chinese provincial panel data between 2000-2014 to study the relationship between the internet communication technology and economic growth within a Cobb-Douglas function under the Solow model. The result indicates that the development of the internet communication technology has a significant role in promoting economic growth in China. At the same time, the human capital has positive interaction effect on the adjustment between the internet and economic growth. So China should continue to increase investment on the internet communication technology and infrastructure construction, and pay more attention to personnel training to promote the sustainable development of economy in China.
RSSI-based Algorithm for Indoor Localization  [PDF]
Xiuyan Zhu, Yuan Feng
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.52B007
Abstract: Wireless node localization is one of the key technologies for wireless sensor networks. Outdoor localization can use GPS, AGPS (Assisted Global Positioning System) [6], but in buildings like supermarkets and underground parking, the accuracy of GPS and even AGPS will be greatly reduced. Since Indoor localization requests higher accuracy, using GPS or AGPS for indoor localization is not feasible in the current view. RSSI-based trilateral localization algorithm, due to its low cost, no additional hardware support, and easy-understanding, it becomes the mainstream localization algorithm in wireless sensor networks. With the development of wireless sensor networks and smart devices, the number of WIFI access point in these buildings is increasing, as long as a mobile smart device can detect three or three more known WIFI hotspots’ positions, it would be relatively easy to realize self-localization (Usually WIFI access points locations are fixed). The key problem is that the RSSI value is relatively vulnerable to the influence of the physical environment, causing large calculation error in RSSI-based localization algorithm. The paper proposes an improved RSSI-based algorithm, the experimental results show that compared with original RSSI-based localization algorithms the algorithm improves the localization accuracy and reduces the deviation.
Implementation of 6LoWPAN and Its Application in Smart Lighting  [PDF]
Zucheng Huang, Feng Yuan
Journal of Computer and Communications (JCC) , 2015, DOI: 10.4236/jcc.2015.33014

Smart lighting system based on PLC (Power Line Communication) is lack of extensibility due to low data rate and non-standard communication protocol. 6LoWPAN is an IP-based communication standard for WSN (Wireless Sensor Network) proposed by IETF. We upgraded the SEMS smart lighting system from PLC to 6LoWPAN, PLC nodes were replaced by 6LoWPAN nodes and centralized controllers were replaced by border routers. 6LoWPAN system testing was carried out on the street after the implementation. The results show that smart lighting system based on 6LoWPAN is better than PLC in transmission rate, signal coverage range, compatibility and extensibility.

Analysis on Supporting Policy of Small and Medium Enterprises of Science and Technology—Taking Hefei of Anhui Province as an Example  [PDF]
Zhenqing Yuan, Yujie Feng
Open Journal of Social Sciences (JSS) , 2017, DOI: 10.4236/jss.2017.54013
Abstract: In recent years, as the carrier of technology innovation and technology industrialization, science-technology small and medium-sized enterprises (STS-ME) make big contribution to transformation of scientific and technological achievements, the industrial structure optimization, the high and new technology development, innovation/entrepreneurship and increasing employment opportunities. STSME has become an important growth point of economic development. However, support policies for STSME also face many problems as policies and regulations and public service system is not perfect, poor financial ecological environment, the relative lack of scientific and technological personnel, to some extent, which hinders the development of STS-ME. Therefore, this article using policy text analysis method-through the extraction and analysis method of keyword network keywords to analyze policies which supports STSME in Hefei. According to the analysis results, we put forward policy recommendations.
Azimuthal Asymmetric Distribution of Hadrons Inside a Jet at Hadron Collider
Yuan, Feng
High Energy Physics - Phenomenology , 2007, DOI: 10.1103/PhysRevLett.100.032003
Abstract: We study the azimuthal asymmetric distribution of hadrons inside a high energy jet in the single transverse polarized proton proton scattering, coming from the Collins effect multiplied by the quark transversity distribution. We argue that the Collins function in this process is the same as that in the semi-inclusive deep inelastic scattering. The experimental study of this process will provide us important information on the quark transversity distribution and test the universality of the fragmentation functions.
Etching Method for the Microstructure of LTCC
Feng Yuan
Modern Applied Science , 2010, DOI: 10.5539/mas.v4n4p70
Abstract: 1wt% hydrochloride acid (HCl), 2wt% hydrofluoric acid (HF), 10wt% hydro nitride acid (HNO3), and 19wt% sodium hydroxide (NaOH), were used to etch the LTCC. The SEM analysis shows that the microstructure of the LTCC A6 (Ferro) can be obtained through the etching of the 19wt% sodium hydroxide. The XRD analysis confirmed that the glass phase can be selectively removed from the glass ceramics in a 19 wt% sodium hydroxide aqueous solution at room temperature after 20 hrs.
Accretion and ejection in Sgr A*
Feng Yuan
Physics , 2010,
Abstract: We review our current understanding to the accretion and ejection processes in Sgr A*. Roughly speaking, they correspond to the quiescent and flare states of the source respectively. The high-resolution {\it Chandra} observations to the gas at the Bondi radius combined with the Bondi accretion theory, the spectral energy distribution from radio to X-ray, and the radio polarization provide us strict constraints and abundant information to the theory of accretion. We review these observational results and describe how the advection-dominated accretion flow model explains these observations. Recently more attentions have been paid to flares in Sgr A*. Many simultaneous multi-wavelength campaigns have been conducted, aiming at uncovering the nature of flares. The main observational properties of flares are briefly reviewed. Especially, the time lag between the peaks of flare at two radio frequencies strongly indicates that the flare is associated with ejection of radio-emitting blobs from the underlying accretion flow. Such kind of episodic jets is distinctive from the continuous jets and are quite common in black hole systems. We introduce the magnetohydrodynamical model for the formation of episodic jets recently proposed based on the analogy with the theory of coronal mass ejection in the Sun. We point out that the various observational appearances of flares should be explained in the framework of this model, since ejection and flare originate from the same physical process.
Heavy quarkonium production in double Pomeron exchange processes in perturbative QCD
Feng Yuan
Physics , 2001, DOI: 10.1016/S0370-2693(01)00582-2
Abstract: We calculate the heavy quarkonium production in double pomeron exchange processes in perturbative QCD by using two-gluon exchange model. For the $P$-wave $\chi_J$ productions, we find $\chi_1$ and $\chi_2$ production amplitudes which vanish in the forward scattering limit. We also calculate direct $J/\psi(\Upsilon)+\gamma$ production in the same approach, and these direct contributions are much smaller than the feeddown contributions from the $P$-wave states.
A New Parameter In Accretion Disk Model
Feng Yuan
Physics , 2000,
Abstract: Taking optically thin accretion flows as an example, we investigate the dynamics and the emergent spectra of accretion flows with different outer boundary conditions (OBCs) and find that OBC plays an important role in accretion disk model. This is because the accretion equations describing the behavior of accretion flows are a set of {\em differential} equations, therefore, accretion is intrinsically an initial-value problem. We argue that optically thick accretion flow should also show OBC-dependent behavior. The result means that we should seriously consider the initial physical state of the accretion flow such as its angular momentum and its temperature. An application example to Sgr A$^*$ is presented.
Possible evidence for the disk origin for the powering of jets in Sgr A* and nearby elliptical galaxies
Feng Yuan
Physics , 2000, DOI: 10.1046/j.1365-8711.2000.03939.x
Abstract: The predicted radio flux for nearby ellipticals by the canonical ADAF(advection-dominated accretion flow) model is well above the observations. If the mass accretion rate favored by the numerical simulation were adopted, the ADAF model would also significantly overpredict the radio flux of Sgr A*. On the observational side, strong evidence for the existence of jets in Sgr A$^*$ and these ellipticals has been obtained. Based on these facts, we propose a truncated ADAF model for these sources. We assume that the accretion disk is truncated at a certain radius within which a jet forms by extracting the energy of the disk therefore the radio flux is greatly suppressed due to the radiative truncation of the disk and the fits to the observational data are excellent. For example, for Sgr A*, the model fits the spectrum very well from radio including the ``excess'' below the break frequency to hard X-ray under a high accretion rate near the simulation value; for M87, the predicted upper limit of the jet location is 24 $R_g$, in excellent agreement with the observational result of < 30 $R_g$. The success of the model supplies a possible piece of evidence for the disk rather than the hole origin for the powering of jets.
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