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Search Results: 1 - 10 of 47311 matches for " Zhen Zhao "
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The Association of Hepatitis B Vaccine Supply Policy with Timing of Receipt of the First Dose of Hepatitis B Vaccination  [PDF]
Zhen Zhao, Trudy V. Murphy
Open Journal of Statistics (OJS) , 2012, DOI: 10.4236/ojs.2012.24053
Abstract: An estimated 800,000 - 1.4 million persons in the US have chronic hepatitis B virus (HBV) infection. The risk for chronic infection is greatest among young children; approximately 90% of infants will remain chronically infected with HBV. Approximately 25% of those who become chronically infected during childhood die prematurely from cirrhosis or liver cancer. Hepatitis B vaccination is the most effective measure to prevent HBV infection and its consequences. In 2006, 29 US states had Hepatitis B Vaccine Supply (HBVS) policy which either supplies hepatitis B vaccine at no cost to all providers for all children or provides hepatitis B vaccine to delivery hospitals-only free of charge for all infants; other 21 US states and the District of Columbia did not have. 17,636 infants born in 2006 obtained from 2007-2009 National Immunization Survey (NIS) were analyzed with survival analysis procedures of Kaplan-Meier estimate and Cox proportional hazards model for complex sample survey to evaluate the association between state HBVS policy and the timing of infant age in days to receipt of hepatitis B vaccination. State HBVS policy is associated with infant age in days from birth to receipt of the first dose of hepatitis B vaccine (P < 0.01), and to completion of the 3-dose hepatitis B vaccine series (P < 0.01). Receipt of the first dose of hepatitis B vaccine occurred 31% earlier among infants residing in states with HBVS policy than among infants residing in states without (adjusted hazards ratio 1.31, 95%CI (1.23, 1.39)). Completion of the 3-dose hepatitis B vaccine series were 12% sooner among infants living in states with HBVS policy than among infants living in states without (adjusted hazards ratio 1.12, 95%CI (1.06, 1.18)). State HBVS policy may help overcome barriers to timely delivery of hepatitis B vaccines to infants.
TeV Blazars as the Sources of Ultra High Energy Cosmic Rays  [PDF]
Bingkai Zhang, Xiaoyun Zhao, Zhen Cao
International Journal of Astronomy and Astrophysics (IJAA) , 2014, DOI: 10.4236/ijaa.2014.43046
Abstract: The origin of ultra high energy cosmic rays (UHECRs) is still an open question in astroparticle physics. TeV blazars are a small group of active galactic nuclei (AGNs). They all have been observed in TeV gamma ray band, and show violent variabilities in flux at all wavelengths. So it is believed that they have abilities to produce UHECRs. To judge whether the TeV blazars can be the candidates of the origin of UHECRs, we collect the information of emission region of 38 TeV blazars, and estimate the maximum energy that the charged particle can be accelerated there. The results show that TeV blazars have abilities to accelerate cosmic rays to the energy above 1018 eV, some even higher than 1020 eV, and they may be the sources of UHECRs.
Influence of Internet plus to International Business Development  [PDF]
Wei Xiong, Zhen Zhao, Jingxuan Fang
American Journal of Industrial and Business Management (AJIBM) , 2016, DOI: 10.4236/ajibm.2016.64050
Abstract: The paper compares the situations of world economy development in past 100 years briefly. With the rapid development of internet, the paper distinguishes the traditional business model from future business model development. As an important tool of international business, internet is becoming a leading role in both business increasing and marketing developing with its users fast growing. With internet plus time coming, international business will be related to internet tightly in current time and future based on internet characteristics.
Impact of Internet plus to China Economy Development  [PDF]
Zhen Zhao, Wei Xiong, Jingxuan Fang
Modern Economy (ME) , 2016, DOI: 10.4236/me.2016.79096
Abstract: China has been fast growing over past 30 years. Whether China could keep relatively high speed sustained growth is very important to the whole world. And it is worthwhile to analyze the reason to keep high speed sustained growth. The paper analyzes the total amount situation of Gross Domestic Product (GDP) of China as the second world economy entity. As a developing fast growing country, China has its own characteristics and also has big gap to the first world economy entity, the USA. With the rapid development of internet, the paper compares the traditional business model to future business model development. As a part of national strategies of China, internet is becoming one of the most important tools for both business increasing and marketing developing with its users fast growing. The relativity between internet and China economy is analyzed through related model. With internet plus time coming, China economy development will be related to internet tightly in current time and future.
Analysis of Alkaline Foam to Water Temperature Model  [PDF]
Zhen Xu, Lihong Zhao, Kai Tan
World Journal of Engineering and Technology (WJET) , 2016, DOI: 10.4236/wjet.2016.43043
Abstract: Factors affecting bath water temperature model include the shape and size of a bath, people’s gesture, volume, individual temperature adaptation as well as body movement in the bath. In addition, the bathroom space, ambient temperature and bath materials will also affect changes of the water temperature to a certain extent. In this paper, the cooling function and linear regression method are used and the MATLAB software is also used to simulate the model of water temperature, alkaline bath foams that obtained can accelerate changes in water temperature.
Joint Power Control and Spectrum Allocation for Cognitive Radio with QoS Constraint  [PDF]
Zhijin Zhao, Zhen Peng, Zhidong Zhao, Shilian Zheng
Communications and Network (CN) , 2010, DOI: 10.4236/cn.2010.21005
Abstract: Spectrum sharing with quality of service (QoS) requirement and power constraint on cognitive users is studied. The objective is to maximize the system throughput. This problem is modeled as a mixed integer nonlinear programming problem and then transformed to a continuous nonlinear programming problem through eliminating integer variables. We propose the joint power control and spectrum allocation algorithm based on particle swarm optimization to obtain the global optimal solution. Simulation results show that the proposed method can achieve higher system throughput and spectrum utilization under the constraints of transmit power and QoS requirement.
Some Properties of a New Class of Generalized Cauchy Numbers
Feng-Zhen Zhao
Online Journal of Analytic Combinatorics , 2011,
Abstract: In this paper, we investigate properties of a new class of generalized Cauchy numbers. By using the method of coefficient, we establish a series of identities involving generalized Cauchy numbers, which generalize some results for the Cauchy numbers. Furthermore, we give some asymptotic approximations of certain sums related to the generalized Cauchy numbers.
Unusual Dielectric Loss Properties of Carbon Nanotube—Polyvinylidene Fluoride Composites in Low Frequency Region (100 Hz < f < 1 MHz)  [PDF]
Yi Zhen, Juan Arredondo, Guang-Lin Zhao
Open Journal of Organic Polymer Materials (OJOPM) , 2013, DOI: 10.4236/ojopm.2013.34016

Systematic investigations on the dielectric properties of multi-walled carbon nanotubes (MWNTs)-polyvinylidene fluoride (PVDF) composites with a wide MWNT concentration range (2 - 9 wt%) have been carried out. It is revealed that the dielectric constant is increased by the addition of an appropriate amount of MWNTs at room temperature. However, when the concentration of MWNTs in the composites reaches above 5 wt%, negative dielectric constants and large dielectric loss in the composites are observed in the low frequency range. The ferroelectric CNT-PVDF polymer composites containing more than 5 wt% MWNTs have a strong dielectric absorption, which has the potential for acoustic applications.

Thermodynamic Analysis and Synthesis Gas Generation by Chemical-Looping Gasification of Biomass with Nature Hematite as Oxygen Carriers  [PDF]
Zhen Huang, Fang He, Anqing Zheng, Kun Zhao, Sheng Chang, Xinai Li, Haibin Li, Zengli Zhao
Journal of Sustainable Bioenergy Systems (JSBS) , 2013, DOI: 10.4236/jsbs.2013.31004
Abstract: Thermodynamic parameters of chemical reactions in the system were carried out through thermodynamic analysis. According to the Gibbs free energy minimization principle of the system, equilibrium composition of the reactions of chemical-looping gasification (CLG) of biomass with natural hematite (Fe2O3) as oxygen carrier were analyzed using commercial software of HSC Chemistry 5.1. The feasibility of the CLG of biomass with hematite was experimental verified in a lab-scale bubbling fluidized bed reactor using argon as fluidizing gas. It was indicated the experimental results were consistent with the theoretical analysis. The presence of oxygen carrier gave a significant effect on the biomass conversion and improved the synthesis gas yield obviously. It was observed that the gas content of CO and H2 was over 70% in CLG of biomass. The reduced hematite particles mainly existed in form of FeO. It was showed that the reduction of natural hematite with biomass proceeds in a stepwise manner from Fe2O3 Fe3O4
Kinetostatic Analysis of 4-R(CRR) Parallel Manipulator with Overconstraints via Reciprocal-Screw Theory
Zhen Huang,Yan Zhao,Jingfang Liu
Advances in Mechanical Engineering , 2010, DOI: 10.1155/2010/404960
Abstract: The paper proposes a new approach based on reciprocal screw theory to analyze kinetostatics of lower-mobility parallel mechanisms with overconstraints and static indeterminacy. For force analysis of parallel mechanisms, the main reactions should be solved firstly, and then all other constraint reactions are easy to be obtained. The approach can remarkably reduce the number of unknowns and keep the number of simultaneous equilibrium equations not more than six each time. For static indeterminacy, it also needs to set some complementary equations. All active forces and constraint reactions of the kinematic pairs can be simultaneously obtained by analyzing the equilibrium of everybody one by one. A 4-R(CRR) parallel manipulator with collinear-force static indeterminacy is taken to introduce the method, which indicates that the method is simple and effective. 1. Introduction Force analysis of lower-mobility parallel manipulators (PMs) is one of the important steps for mechanism design, simulation, and control.It generally needs to solve for active forces and constraint reactions of all kinematic pairs. Force analysis contains statics and dynamics. Only the statics analysis is needed when the device moves at low speed. However, when it moves at high speed, the inertia forces of links cannot be neglected, and it needs dynamics analysis. The issue has attracted huge attention in the community. Tsai [1] presented the statics and dynamics of parallel mechanisms; Merlet [2] discussed the dynamics of PMs. Zhang and Gosselin [3, 4] discussed a general kinetostatic model of PMs. Gallardo et al. [5] solved the dynamics of PMs by screw theory and the principle of virtual work. Ider [6] developed a method for the inverse dynamic solution of PMs in the presence of drive singularities. Li et al. [7] presented a method for the inverse dynamic formulation of the 3-DOF modules of two PMs. Russo et al. [8] discussed the static balancing of parallel robots. Sokolov and Xirouchakis [9] presented a dynamics analysis of a 3-DOF PM. Lu et al. [10] solved active and passive forces of some PMs. Callegari and Cammarata [11] discussed the dynamics of a 3-CRU parallel robot. Jaime et al. [12] approached the dynamic analysis of 2(3-RPS) manipulator via screw theory and the principle of virtual work. Zhou et al. [13] studied the static solving of a 3-DOF 3-RRR parallel mechanism. The statics of spatial mechanisms can be traded by various methods, such as the vector method [14], the dual vector and dual number quaternions [15], the screw calculus [16], and the principle of virtual work
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