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Search Results: 1 - 10 of 45618 matches for " Lei Guo "
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Parameter Analysis and Numerical Simulation of Hydrogen Production by Steam Reforming of Dimethyl Ether  [PDF]
Lei Guo, Cong Li
Journal of Power and Energy Engineering (JPEE) , 2018, DOI: 10.4236/jpee.2018.611001
Abstract: Hydrogen production through dimethyl ether steam reforming is an attractive option for mobile applications of hydrogen fuel cells. Hydrogen is a major trend in the future of energy development. It is not only pollution-free, but also has a high energy density. Therefore, research on hydrogen fuel cells is particularly important. In this paper, a numerical research on dimethyl ether steam reforming reaction in a reactor has been presented using a computational fluid dynamics. A three-dimensional reactor model developed by the commercial software COMSOL (version 5.2a) was used to simulate the reaction characteristics by modifying reforming conditions. The simulation results indicate the temperature distribution, mass distribution, and reveal the dependency of dimethyl ether reforming reaction rate on temperature, pressure, the length of the reactor. The yield of H2 and conversion of dimethyl ether with different mass ratios and inlet temperature (200°C, 300°C, 400°C, 500°C) were examined. The governing equations in the model include conservations of mass, momentum, energy and chemical species.
Molecular Dynamics Simulation of Mechanical Properties for α-SiO2 Crystal  [PDF]
Jierong Guo, Lei Ma
Journal of Modern Physics (JMP) , 2019, DOI: 10.4236/jmp.2019.106040
Abstract: The mechanical properties of the α-SiO2 crystal are studied by molecular dynamics method with Tersoff potential function. The results show that the α-SiO2 crystal goes through elastic deformation, plastic deformation and fracture deformation in the process of uniaxial loading at room temperature. The α-SiO2 is from crystal phase transformation to amorphous phase in plastic deformation. And also by studying the influence of temperature on the tensile mechanical properties of α-SiO2, it finds that the yield strength and elastic modulus of α-SiO2 decrease gradually as the temperature increases. Moreover, the higher the temperature, the lower the fracture stress and fracture strain; the α-SiO2 crystal is easy to be broke under high temperature uniaxial loading. And it also finds that the crack is able to decrease the mechanical properties of α-SiO2 crystal.
Origination and development of syndrome concept in traditional Chinese medicine
Zhong Xi Yi Jie He Xue Bao , 2006,
Abstract: In the opinion of dialectical materialism, concept is developing with the deepening and broadening of human being's mind. The developing process of syndrome concept in traditional Chinese medicine also takes the same way. In the Sui and Tang Dynasties, the connotation of syndrome concept was defined and the embryonic form of syndrome differentiation of zang-fu viscera was formed. In the Song, Jin and Yuan Dynasties, the development of syndrome concept embodied in optimizing the theoretical research based on clinical practice and experiences according to many medical masters in different denominations. The syndrome differentiation of eight principles was established to standardize and perfect the principles of syndrome differentiation in the Qing Dynasty. Modern research of syndrome concept is manifested in objectifying the process of research of syndrome and diseaes in different levels and aspects by use of advanced scientific technology.
Exploring the capability and limits of the feedback mechanism
Lei Guo
Mathematics , 2003,
Abstract: Feedback is a most important concept in control systems, its main purpose is to deal with internal and/or external uncertainties in dynamical systems, by using the on-line observed information. Thus, a fundamental problem in control theory is to understand the maximum capability and potential limits of the feedback mechanism. This paper gives a survey of some basic ideas and results developed recently in this direction, for several typical classes of uncertain dynamical systems including parametric and nonparametric nonlinear systems, sampled-data systems and time-varying stochastic systems.
Research of Hydrogen Production by Dimethyl Ether Reforming in Fuel Cells  [PDF]
Lei Guo
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104266
Dimethyl ether is a kind of clean fuel, which is expected to replace traditional fuel to achieve high efficiency and low emission. The research of hydrogen production by vehicle dimethyl ether reforming is imminent. This article summarizes and comments the progress of hydrogen production by dimethyl ether reforming, briefly analyzing new method of preparing catalyst. Three existing methods for hydrogen from dimethyl ether, namely steam reforming, autothermal reforming and partial oxidation reforming, are introduced. In this paper, recent researches in the field of hydrogen from dimethyl ether are reviewed.
Primary and secondary school mental health teachers in professional identity of intervention programs  [PDF]
Hao Lei, Cheng Guo, Yanling Liu
Health (Health) , 2012, DOI: 10.4236/health.2012.412191
Abstract: To explore the impact of teacher training on the professional identity of primary and secondary school mental health teachers, this study conducted a half-month professional development training program to 54 primary and secondary school mental health teachers, and performed measurement on the professional identity of the teachers in the experimental group and the control group with “Teachers’ Professional Identity Questionnaire”. The result shows that after the training there is a significant improvement in the professional identity of the teachers in the experimental group, and the teachers’ scores on the four dimensions of profession identity: the sense of role, the professional behavioral tendency, the occupational values, and the sense of belonging, all increased significantly. This indicates that the curriculum intervention for the primary and secondary school mental health teachers could effectively improve the teachers’ professional identity.
Recommendations to Patent Protection of Computer Program-Related Invention in China  [PDF]
Lei Dai, Dong Guo, Hao Qin
Open Journal of Social Sciences (JSS) , 2017, DOI: 10.4236/jss.2017.56013
Abstract: The recommendations to patent protection of computer program-related invention in China are analyzed. They mainly focus on the following points: There are some contradictions in guideline for examination and thus the protection scope of computer program-related invention shall be enlarged. Meanwhile, in consideration of the balance between inventor and public, the reasons for shortening the term of protection for computer program-related invention were given. Finally, emendation of publication rule of computer program-related inventions was suggested.
The Climate Change in Qingdao during 1899-2015 and Its Response to Global Warming  [PDF]
Feiyan Guo, Yan Ma, Kaijing Zhang, Lei Han, Lina Guo
Journal of Geoscience and Environment Protection (GEP) , 2018, DOI: 10.4236/gep.2018.69005
Abstract: In this work, the average mean (TAvg), maximum (TMax), and minimum temperature (TMin) and precipitation records of Qingdao from 1899 to 2015 are analyzed. The TAvg, TMax and TMin all go through several warm and cold periods, and exhibit statistically significant linear warming trend especially in spring and winter, as a response to global warming. Besides, the TAvg reflects more the TMin evolution for the most part, either as a trend or an abrupt change, and the contribution of TMin to Tavg is far greater than that of TMax. The abrupt change year of climate is also around 1979 in Qingdao, and it is 2 or 3-years later than the TAvg for the TMin, while there is no abrupt change of TMax. In terms of the precipitation in Qingdao, it varies periodically and dramatically with a slow increasing trend. As for the seasonal precipitation, the precipitation varies widely year by year for the four seasons but with no obvious variation trend except for spring.
Sterile Neutrinos as the Warm Dark Matter in the Type II Seesaw Model
Guo, Wan-lei
High Energy Physics - Phenomenology , 2007, DOI: 10.1103/PhysRevD.77.033005
Abstract: In the framework of type II seesaw mechanism we discuss the number of sterile right-handed Majorana neutrinos being the warm dark matter (WDM). When the type II seesaw mass term $M_\nu ^{II}$ is far less than the type I seesaw mass term $M_\nu ^{I}$, only one of three sterile neutrinos may be the WDM particle. On the contrary, the WDM particles may contain all sterile neutrinos. If $M_\nu ^{II} \sim M_\nu ^{I}$, the allowed number is not more than $N - 1$ for $N$ sterile neutrinos. It is worthwhile to stress that three different types of neutrino mass spectrum are permitted when $M_\nu ^{II} \gg M_\nu ^{I}$ and $M_\nu ^{II} \sim M_\nu ^{I}$.
Improved Cryptanalysis of CMC Chaotic Image Encryption Scheme
Jiansheng Guo,Lei Zhang
International Journal of Image, Graphics and Signal Processing , 2010,
Abstract: Recently, chaos has attracted much attention in the field of cryptography. To study the security with a known image of a symmetric image encryption scheme, the attack algorithm of equivalent key is given. We give the known image attacks under different other conditions to obtain the equivalent key. The concrete step and complexity of the attack algorithm is given. So the symmetric image encryption scheme based on 3D chaotic cat maps is not secure.
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