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Modeling of the nanoparticle coagulation in pulsed radio-frequency capacitively coupled C_2H_2 discharges

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Chinese Physics B 2015年第7期24卷 330-335页

作者：刘相梅李奇楠李瑞 School of Science Qiqihar University

The role of pulse parameters on nanoparticle property is investigated self-consistently based on a couple of fluid model and aerosol dynamics model in a capacitively coupled parallel-plate acetylene（C2H2） discharge. In this model, the mass continuity equation, momentum balance equation, and energy balance equation for neutral gas are taken into ***, the thermophoretic force arises when a gas temperature gradient exists. The typical results of this model are positive and negative ion densities, electron impact collisions rates, nanoparticle density, and charge distributions. The simulation is performed for duty ratio 0.4/0.7/1.0, as well as pulse modulation frequency from 40 kHz to 2.7 MHz for pure C2H2 discharges at a pressure of 500 mTorr. We find that the pulse parameters, especially the duty ratio, have a great affect on the dissociative attachment coefficient and the negative density. More importantly, by decreasing the duty ratio, nanoparticles start to diffuse to the wall. Under the action of gas flow, nanoparticle density peak is created in front of the pulse electrode,where the gas temperature is smaller.

关键词： nanoparticle coagulation pulsed radio-frequency capacitively coupled acetylene discharges

Modification of gravitational redshift of x-ray burst produced by pulsar surface magnetoplasma

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Chinese Physics B 2008年第1期17卷 356-361页

作者：祝俊季沛勇 Department of Physics Shanghai University

In this paper, the propagation of x-ray bursts in the magnetoplasma of pulsar magnetosphere is discussed. The electromagnetic interaction between x-ray bursts and magnetoplasma is described as some geometry. The electromagnetic effects of surface superstrong magnetic field and dynamic effects of outflowing magnetoplasma of pulsars are treated as an optical metric. The Gordon metric is introduced to represent the gravitational metric and optical metric. So the propagation of x-ray bursts in magnetoplasma of pulsars can be described as x-ray bursts transmitting in an effective space characterized by Gordon metric. The modification of gravitational redshift, attributed to the flowing magnetoplasma of pulsars, is obtained and it is shown that the modification is of redshift and can reach the same magnitude as the gravitational redshift for ordinary pulsars.

关键词： pulsars x-ray spectra relativity and gravitation redshift

Spiral Wave in Small-World Networks of Hodgkin-Huxley Neurons

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Communications in Theoretical Physics 2010年第9期54卷 583-588页

作者：马军杨利建吴莹张材荣 Department of Physics Lanzhou University of Technology Department of Physics Central China Normal University School of Science Xi'an University of Technology

The effect of small-world connection and noise on of Hodgkin-Huxley neurons are investigated in detail. Some the formation and transition of spiral wave in the networks interesting results are found in our numerical studies, i） The quiescent neurons are activated to propagate electric signal to others by generating and developing spiral wave from spiral seed in small area. ii） A statistical factor is defined to describe the collective properties and phase transition induced by the topology of networks and noise, iii） Stable rotating spiral wave can be generated and keeps robust when the rewiring probability is below certain threshold, otherwise, spiral wave can not be developed from the spiral seed and spiral wave breakup occurs for a stable rotating spiral wave. iv） Gaussian white noise is introduced on the membrane of neurons to study the noise-induced phase transition on spiral wave in small-world networks of neurons. It is confirmed that Ganssian white noise plays active role in supporting and developing spiral wave in the networks of neurons, and appearance of smaller factor of synchronization indicates high possibility to induce spiral wave.

关键词： spiral wave small-world network Hodgkin-Huxley neurons noise

Synthesis, spectral, optical and anti-inflammatory activity of complexes derived from 2-aminobenzohydrazide with some rare earths

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Journal of Rare Earths 2015年第7期33卷 758-764页

作者： Nasser Mohammed Hosny El Sayed A.El Morsy Yousery E.Sherif Chemistry Department Faculty of Science Port-Said University Clinical Pharmacology Department Faculty of Medicine Mansoura University Pharmacology and Therapeutics Department Qassim College of Medicine Qassim University Department of Chemistry Faculty of Science and Arts Taibah University

Three new metal complexes derived from Er（Ⅲ）, Dy（Ⅲ） and Zr（Ⅳ） with 2-aminobenzohydrazide （ABH） were synthesized and characterized by elemental analyses, IR, ^1H-NMR, ES-MS and transmission electron microscopy （TEM）. The morphology and the particle size were determined by TEM. The results showed that the ligand acted as neutral bi-dentate coordinating to the metal ions through the carbonyl oxygen and amidic amino nitrogen. The aromatic amine group remained inert towards coordination. The optical band gap was measured and found to be 3.3, 3.5 and 4.3 eV for Er（Ⅲ）, Dy（Ⅲ） and Zr（Ⅳ）, respectively. The optical band gap values indicated a semi-conducting nature of the investigated complexes. The anti-inflammatory and analgesic activities of the tested compounds were determined and compared with standard meloxicam.

关键词： Er(Ⅲ) Dy(Ⅲ) Zr(Ⅳ) metal complexes optical band gap rare earths

Correlation functions of gauged linear σ-model

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Science China Mathematics 2016年第5期59卷 823-838页

作者： TIAN Gang XU GuangBo Beijing International Center for Mathematical Research Peking University Department of Mathematics Princeton University Department of Mathematics University of California at Irvine

This is the second paper in a series following Tian and Xu(2015), on the construction of a mathematical theory of the gauged linear σ-model(GLSM). In this paper, assuming the existence of virtual moduli cycles and th... 详细信息

关键词： gauged linear σ-model correlation function moduli space

Assessment of the determinants that influence the adoption of sustainable soil and water conservation practices in Techiman Municipality of Ghana

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International Soil and Water Conservation Research 2019年第3期7卷 248-257页

作者： Kwasi Adjepong Darkwah Joana Deladem Kwawu Frank Agyire-Tettey Daniel Bruce Sarpong Department of Statistics University of GhanaGhana Department of Economics University of GhanaGhana Department of Economics and Agribusiness University of GhanaGhana

This paper assesses the relationship between farmer characteristics and the degree to which nine soil and water conservation practices (SWCPs) are adopted by 300 maize farmers in Techiman Municipality,*** were surveyed for their adoption of nine SWCPs,and 24 other characteristics including demographics,socio-economic factors,risk factors and costs of *** soil and water conservation practices (SWCPs) in sub-Saharan Africa such as Ghana are important because they have positive effects on yield,increase sustainability of farming,stop degradation and reduce soil *** adoption of sustainable soil and water conservation practices in the agricultural industry of Ghana has been *** study aims to explain differences in farmer adoption of SWCPs,by assessing factors that vary with the number of different SWCPs used by ***,the Poisson model was *** results show that farmer's household size,farm size,access to credit services and formal training of maize farmer have a positive significant association with the number of soil and water conservation practices adopted by maize farmers while distance to nearest output market,distance to input center,access to extension services,and risk of pest and diseases have a negative significant association with the number of soil and water conservation practices adopted by maize farmers at 5% significance *** study concludes that any further research in Techiman Municipality on soil and water conservation practices should acknowledge the mixture of personal and demographic,institutional,socio-economic and risk *** suggests that agricultural polities formulated by the government should be aimed at supporting maize farmers to have access to extension service contact for frequent disseminating of agricultural technology information which is likely to increase the rate of adoption of soil and water conservation practices.

关键词： Sustainable soil and water conservation practices Adoption Correlation Poisson regression

Two-dimensional cellular automaton model for simulating structural evolution of binary alloys during solidification

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Transactions of Nonferrous Metals Society of China 2006年第6期7卷 1410-1416页

作者：张林张彩碚 School of Science Northeastern University

Two-dimensional cellular automaton(CA)simulations of phase transformations of binary alloys during solidification were *** modelling incorporates local concentration and heat changes into a nucleation or growth function,which is utilized by the automaton in a probabilistic *** simulations may provide an efficient method of discovering how the physical processes involved in solidification processes dynamically progress and how they interact with each other during *** simulated results show that the final morphology during solidification is related with the cooling *** established model can be used to evaluate the phase transformation of binary alloys during solidification.

关键词： binary alloys phase transformation solidification diffusion nucleation computer simulation cellular automaton

A Chemical Reactor Network for Oxides of Nitrogen Emission Prediction in Gas Turbine Combustor

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Journal of Thermal Science 2014年第3期23卷 279-284页

作者： Nguyen Thanh Hao Industrial university of HoChiMinh City

This study presents the use of a new chemical reactor network(CRN) model and non-uniform injectors to predict the NOx emission pollutant in gas turbine combustor. The CRN uses information from Computational Fluid Dynamics(CFD) combustion analysis with two injectors of CH4-air mixture. The injectors of CH4-air mixture have different lean equivalence ratio, and they control fuel flow to stabilize combustion and adjust combustor's equivalence ratio. Non-uniform injector is applied to improve the burning process of the turbine combustor. The results of the new CRN for NOx prediction in the gas turbine combustor show very good agreement with the experimental data from Korea Electric Power Research Institute.

关键词： Chemical Reactor Networks (CRN) Computational Fluid Dynamics (CFD) Perfectly Stirred Reactor (PSR) Plug Flow Reactor (PFR) Gas Turbine Combustor Oxides of Nitrogen Emission (NOx).

Numerical analysis of rock fracturing by gas pressure using the extended finite element method

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Petroleum Science 2015年第2期12卷 304-315页

作者： Majid Goodarzi Soheil Mohammadi Ahmad Jafari Department of Civil Engineering and Geoscience University of Newcastle School of Civil Engineering University of Tehran School of Mining Engineering University of Tehran

High energy gas fracturing is a simple approach of applying high pressure gas to stimulate wells by gen- erating several radial cracks without creating any other damages to the wells. In this paper, a numerical algorithm is proposed to quantitatively simulate propagation of these fractures around a pressurized hole as a quasi-static phenomenon. The gas flow through the cracks is assumed as a one-dimensional transient flow, governed by equations of conservation of mass and momentum. The fractured medium is modeled with the extended finite element method, and the stress intensity factor is calculated by the simple, though sufficiently accurate, displacement ex- trapolation method. To evaluate the proposed algorithm, two field tests are simulated and the unknown parameters are determined through calibration. Sensitivity analyses are performed on the main effective parameters. Considering that the level of uncertainty is very high in these types of engineering problems, the results show a good agreement with the experimental data. They are also consistent with the theory that the final crack length is mainly determined by the gas pressure rather than the initial crack length produced by the stress waves.

关键词： Gas fracturing Numerical modeling Extended finite element Fracture mechanics