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Search Results: 1 - 10 of 121607 matches for " Yuan Zhang "
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OFDI Reverse Technology Spillovers of Western China  [PDF]
Xianping Yuan, Yuanyuan Zhang
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.62006
As an important technology spillover path, FDI plays an increasingly important role in promoting domestic technological progress and optimizing industrial structure. This paper selects the data of GDP, R&D investment and fixed assets investment and employment in China from 2004 to 2011, and adopts a simple and classical linear-model to investigate the relationship between to increase the risk. From the regression results (t-statistics and p-value), there is the effect of reverse technology spillovers in Western China. And China in western region has the problems that economy and science and technology are underdeveloped, so the western region through the increase of foreign direct investment to promote technological upgrading is very necessary. At the same time, we believe that the government of the western region can improve and enhance the technical level, through foreign direct investment, so as to promote local economic development; at the same time, the western region enterprises through overseas investment, especially in technology intensive industry investment to improve the technical level, and mergers and acquisitions may be the effective way to obtain such a spillover effect.
Rigidity for local holomorphic isometric embeddings from ${\BB}^n$ into ${\BB}^{N_1}\times... \times{\BB}^{N_m}$ up to conformal factors
Yuan Yuan,Yuan Zhang
Mathematics , 2010,
Abstract: In this article, we study local holomorphic isometric embeddings from ${\BB}^n$ into ${\BB}^{N_1}\times... \times{\BB}^{N_m}$ with respect to the normalized Bergman metrics up to conformal factors. Assume that each conformal factor is smooth Nash algebraic. Then each component of the map is a multi-valued holomorphic map between complex Euclidean spaces by the algebraic extension theorem derived along the lines of Mok and Mok-Ng. Applying holomorphic continuation and analyzing real analytic subvarieties carefully, we show that each component is either a constant map or a proper holomorphic map between balls. Applying a linearity criterion of Huang, we conclude the total geodesy of non-constant components.
Risk Assessment of Agricultural Products Supply-Chain Finance Based on D-S Theory  [PDF]
Yuan Zhang, Lian Duan, Gefu Zhang
American Journal of Computational Mathematics (AJCM) , 2014, DOI: 10.4236/ajcm.2014.44031
Abstract: Agricultural products supply-chain finance, as one of the solutions to the issue of “capital problems” of agriculture, countryside and farmers, has proposed a kind of characteristics model to assess the risk of agricultural production, processing and marketing, which can improve the issue of farmers and enterprises lacking of funds. This model is proposed on the basis of uncertain information processing method of D-S theory and its data combination rules, combined with the “discount rate” correction model, and it includes a risk assessment index system of agricultural products supply-chain finance, fully considering the five aspects of production, processing, marketing, cooperation of supply chain and collateral. At last, a taro supply chain is taken for example. And the risk assessment of its supply-chain finance based on this model has been discussed in detail. And the result has proved that the model and its algorithm are practical and feasible.
13C-18O Bonds in Precipitated Calcite and Aragonite: An ab Initio Study  [PDF]
Jie Yuan, Zhigang Zhang, Yigang Zhang
Open Journal of Geology (OJG) , 2014, DOI: 10.4236/ojg.2014.49034
Abstract: The 13C-18O bonds in carbonates are potential single-phase geo-thermometers. However, their theoretical distributions (noted as Δ47s) in CO2 degassed from calcite and aragonite with phosphoric acid are unclear. Thus, the isotope reactions of 13C-18O bonds on the growing surfaces of calcite (0001) and aragonite (001) planes were investigated using ab initio techniques. It was found that these reactions determined 13C-18O clumped isotope signatures in bulk calcite and aragonite minerals with novel Δ47 polynomials: \"\"
Simulation of Substrate Temperature Distribution in Diamond Films Growth on WC-Co Tools Using HFCVD Method  [PDF]
Jianguo Zhang, Yigao Yuan, Jinjiang Zhang
Journal of Materials Science and Chemical Engineering (MSCE) , 2018, DOI: 10.4236/msce.2018.68007
Abstract: The substrate temperature is an important factor for diamond films fabricated by hot filament chemical vapor deposition (HFCVD), which affects the grain size and quality of diamond films. In order to deposit polycrystalline diamond films with good quality on the cutting tool, the substrate temperature distribution needs to be further studied. Thus three-dimensional finite element simulations are used to investigate the temperature field with different arrangements of filaments which have profound influences on substrate temperature distribution. Based on the simulation results, the optimum parameters of distance away from drill points and gap between filaments are founded. Subsequently, experiments of depositing diamond films on WC-Co drills are conducted with the optimum values gained from the simulation results. Then, the as-fabricated diamond films are investigated by scanning electron microscopy (SEM) and Raman spectroscopy. The results indicate that the surface of drill are covered with a layer of continuous diamond films, which validate that the simulated deposition parameters are conducive and provide a new method to adjust the substrate temperature distribution in the CVD reactor for depositing diamond films.
Butan-1-aminium tetrachloridoferrate(III)–18-crown-6 (1/1)
Yuan Zhang
Acta Crystallographica Section E , 2013, DOI: 10.1107/s160053681204994x
Abstract: In the crystal of the title compound, (C4H12N)[FeCl4]·C12H24O6, the butan-1-aminium cation and the tetrachloridoferrate(III) anion have m symmetry: in the cation, the non-H atoms are located on the mirror plane and in the anion, the FeIII atom and two Cl atoms are located on the mirror plane. The 18-crown-6 molecule also has m symmetry, with two O atoms located on the mirror plane. The butan-1-amine cation and the 18-crown-6 molecule are connected by N—H...O hydrogen bonds.
N,N,2,4,6-Pentamethylanilinium hexafluorophosphate
Yuan Zhang
Acta Crystallographica Section E , 2013, DOI: 10.1107/s1600536812049379
Abstract: In the crystal structure of the title salt, C11H18N+·PF6 , the cation and anion are connected via an N—H...F hydrogen bond; weak C—H...F hydrogen bonding also occurs between the cations and anions.
Sustainable Ecosystem Planning Based on Discrete Stochastic Dynamic Programming and Evolutionary Game Theory
Yuan Zhang
Mathematics , 2013,
Abstract: This paper proposed a discrete stochastic dynamic programming (SDP) model for sustainable ecosystem (SE) planning of the Loess Plateau in Northwestern, China, and analyzed the ecological resource planning by the evolutionary game model in the decision-making process. The main objective is to explore a new approach of SE planning from a viewpoint of discrete SDP and evolutionary game theory, with a specific application in the area of ecological resource planning such as water management problems. In contrast to previous work, the proposed SDP method focuses on the transition probability matrix of the ecosystem in a statistic sense, and uses the DP algorithm to obtain the optimal ecological resource planning strategies among multi-subsystems, then analyzes impacts of decision between different users. Firstly, the application background and the concept of SE planning are introduced. Then, a brief overview of existing theory for analyzing sustainable ecosystem is presented. Furthermore, a SDP-based mathematical model and its application to water resource planning of central areas of Loess Plateau are presented as an example. Finally, supplementary analysis of impacts between different users in SE planning as a game playing is provided.
Optimization Approach to Parametric Tuning of Power System Stabilizer Based on Trajectory Sensitivity Analysis
Yuan Zhang
Computer Science , 2013,
Abstract: This paper proposed an transient-based optimal parametric tuning method for power system stabilizer (PSS) based on trajectory sensitivity (TS) analysis of hybrid system, such as hybrid power system (HPS). The main objective is to explore a systematic optimization approach of PSS under large disturbance of HPS, where its nonlinear features cannot be ignored, which, however, the traditional eigenvalue-based small signal optimizations do neglect the higher order terms of Taylor series of the system state equations. In contrast to previous work, the proposed TS optimal method focuses on the gradient information of objective function with respect to decision variables by means of the trajectory sensitivity of HPS to the PSS parameters, and optimizes the PSS parameters in terms of the conjugate gradient method. Firstly, the traditional parametric tuning methods of PSS are introduced. Then, the systematic mathematical models and transient trajectory simulation are presented by introducing switching/reset events in terms of triggering hypersurfaces so as to formulate the optimization problem using TS analysis. Finally, a case study of IEEE three-machine-nine-bus standard test system is discussed in detail to exemplify the practicality and effectiveness of the proposed optimal method.
Analysis of Lifetime of Large Wireless Sensor Networks Based on Multiple Battery Levels  [PDF]
Ruihua ZHANG, Zhiping JIA, Dongfeng YUAN
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2008, DOI: 10.4236/ijcns.2008.12018
Abstract: Due to the limited transmission range, data sensed by each sensor has to be forwarded in a multi-hop fashion before being delivered to the sink. The sensors closer to the sink have to forward comparatively more messages than sensors at the periphery of the network,and will deplete their batteries earlier. Besides the loss of the sensing capabilities of the nodes close to the sink, a more serious consequence of the death of the first tier of sensor nodes is the loss of connectivity between the nodes at the periphery of the network and the sink; it makes the wireless networks expire. To alleviate this undesired effect and maximize the useful lifetime of the network, we investigate the energy consumption of different tiers and the effect of multiple battery levels, and demonstrate an attractively simple scheme to redistribute the total energy budget in multiple battery levels by data traffic load. We show by theoretical analysis, as well as simulation, that this substantially improves the network lifetime.
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