OALib Journal期刊

ISSN: 2333-9721




2019 ( 8 )

2018 ( 153 )

2017 ( 102 )

2016 ( 146 )


匹配条件: “Zhou He” ,找到相关结果约52766条。
Synthesis, Characterization, and Activity of Tin Oxide Nanoparticles: Influence of Solvothermal Time on Photocatalytic Degradation of Rhodamine B  [PDF]
Zuoli He, Jiaqi Zhou
Modern Research in Catalysis (MRC) , 2013, DOI: 10.4236/mrc.2013.23A003

The SnO2 spheres-like nanoparticles have been successfully synthesized by a microwave solvothermal method, in which SnCl2·2H2O, poly(vinylpyrrolidone) PVP, H2O2 and NaOH as raw materials. The as-synthesized products have been characterized by X-ray diffraction, scanning electron microscope, and UV/Vis/NIR spectrophotometer. Photocatalytic activities of the samples have been evaluated by the degradation of rhodamine B (RhB) under UV-light illumination. Results showed that these products with diameter about 1 - 2 μm, and when the reaction time prolong, the surface of the SnO2 spheres will change to rough and then smooth when the time even longer. The product with nanorods on its surface shows the higher photocatalytic activity and red shift in the UV-vis absorption, which are relative to the unique structure. At last we studied the electron transfer reactions during photo-oxidation of RhB.

Heat Pump Technology Applies on Air-conditioners Impact on Electric Power  [PDF]
Kun Liu, Xiaoyan Zhou, Hailang He
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B049
Abstract: In recent years, power grid has been experienced in difficult times that there is a shortage of demand load among market, and more and more black out exited that bothered residents’ normal life. With the increment of energy consumption and power load, this problem will be more serious without any feasible solutions. Besides, the air conditioning system is the largest residential energy consumer. In this report, a GSHP air conditioning system has been illustrated and compared with the conventional air conditioning system currently used in Chengdu, Sichuan province, China. The benefits of using the GSHP system are not only on cost saving, but also energy saving and eco-friendly.
Functional analysis of OAT gene in Aspergillus Niger  [PDF]
Chuang Zhou, Xihong He, Hao Liu
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.410B036
Mitochondrial oxaloacetate transporter protein encoded by OAT gene transports oxaloacetate from cytoplasm into mitochondria. To investigate the primary effects of OAT gene on relative metabolism in Aspergillus niger, a oat-deleted mutant was derived from wild-type A. niger ATCC1015 using the double-crossover chromosome replacement technique. Then batch fermentation was performed to evaluate the mutant. Compared with the wild type, the mutant showed lower organic acids production, with the experimental data that the production of pyruvate and 2-ketoglutarate decreased by 31.6% and 35.7%, respectively, and by contrast, the mutant showed higher glycerol formation. The results suggest that OAT gene plays significant roles on metabolism in A. niger.
The Actual Nature of Light (Ⅰ) Reveal the Mystery about the Actual Nature of Light from Newton, Einstein to the Recent Mistakes  [PDF]
He-Zhou Wang, He-Xiang He, Jie Feng, Xiao-Dong Chen, Wei Lin
Journal of Quantum Information Science (JQIS) , 2011, DOI: 10.4236/jqis.2011.12008
Abstract: When Newton became the President of the Royal Society, he proposed corpuscle concept (wave-particle duality) to destroy the fruitions of Hooke and Huygens, because Newton mistook Hooke and Huygens as his enemies. Thereafter, this erroneous concept governed the scientific world for more than one hundred years. This paper will reveal the mystery: why corpuscle concept could govern the scientific world for one hundred years after Newton’s death. In the beginning of last century, photon, a palingenesis of Newton’s corpuscle, was proposed by Einstein again, as a sudden whim, because Planck strongly opposed this wrong concept, since 1907, Einstein strongly doubted this concept. Finally, Einstein disappointedly said: “The quanta really are a hopeless mess.” This paper will reveal the mystery: why photon concept can govern the scientific world until now, and give the evidences for the actual nature of light.
The climatic suitability for maize cultivation in China
QiJin He,GuangSheng Zhou
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-011-4807-2
Abstract: To provide scientific support for planning maize production and designing countermeasures against the effects of climate change on the national maize crop, we analyzed the climatic suitability for cultivating maize across China. These analyses were based on annual climate indices at the Chinese national level; these indices influence the geographical distribution of maize cultivation. The annual climate indices, together with geographical information on the current cultivation sites of maize, the maximum entropy (MaxEnt) model, and the ArcGIS spatial analysis technique were used to analyze and predict maize distribution. The results show that the MaxEnt model can be used to study the climatic suitability for maize cultivation. The eight key climatic factors affecting maize cultivation areas were the frost-free period, annual average temperature, 0°C accumulated temperature, 10°C accumulated temperature continuous days, 10°C accumulated temperature, annual precipitation, warmest month average temperature, and humidity index. We classified climatic zones in terms of their suitability for maize cultivation, based on the existence probability determined using the MaxEnt model. Furthermore, climatic thresholds for a potential maize cultivation zone were determined based on the relationship between the dominant climatic factors and the potential maize cultivation area. The results indicated that the importance and thresholds of main climate controls differ for different maize species and maturities, and their specific climatic suitability should be studied further to identify the best cultivation zones. The MaxEnt model is a useful tool to study climatic suitability for maize cultivation.
Secure On-Off Transmission Design with Channel Estimation Errors
Biao He,Xiangyun Zhou
Mathematics , 2013,
Abstract: Physical layer security has recently been regarded as an emerging technique to complement and improve the communication security in future wireless networks. The current research and development in physical layer security is often based on the ideal assumption of perfect channel knowledge or the capability of variable-rate transmissions. In this work, we study the secure transmission design in more practical scenarios by considering channel estimation errors at the receiver and investigating both fixed-rate and variable-rate transmissions. Assuming quasi-static fading channels, we design secure on-off transmission schemes to maximize the throughput subject to a constraint on secrecy outage probability. For systems with given and fixed encoding rates, we show how the optimal on-off transmission thresholds and the achievable throughput vary with the amount of knowledge on the eavesdropper's channel. In particular, our design covers the interesting case where the eavesdropper also uses the pilots sent from the transmitter to obtain imperfect channel estimation. An interesting observation is that using too much pilot power can harm the throughput of secure transmission if both the legitimate receiver and the eavesdropper have channel estimation errors, while the secure transmission always benefits from increasing pilot power when only the legitimate receiver has channel estimation errors but not the eavesdropper. When the encoding rates are controllable parameters to design, we further derive both a non-adaptive and an adaptive rate transmission schemes by jointly optimizing the encoding rates and the on-off transmission thresholds to maximize the throughput of secure transmissions.
Dimension reduction based on constrained canonical correlation and variable filtering
Jianhui Zhou,Xuming He
Mathematics , 2008, DOI: 10.1214/07-AOS529
Abstract: The ``curse of dimensionality'' has remained a challenge for high-dimensional data analysis in statistics. The sliced inverse regression (SIR) and canonical correlation (CANCOR) methods aim to reduce the dimensionality of data by replacing the explanatory variables with a small number of composite directions without losing much information. However, the estimated composite directions generally involve all of the variables, making their interpretation difficult. To simplify the direction estimates, Ni, Cook and Tsai [Biometrika 92 (2005) 242--247] proposed the shrinkage sliced inverse regression (SSIR) based on SIR. In this paper, we propose the constrained canonical correlation ($C^3$) method based on CANCOR, followed by a simple variable filtering method. As a result, each composite direction consists of a subset of the variables for interpretability as well as predictive power. The proposed method aims to identify simple structures without sacrificing the desirable properties of the unconstrained CANCOR estimates. The simulation studies demonstrate the performance advantage of the proposed $C^3$ method over the SSIR method. We also use the proposed method in two examples for illustration.
Convergence and Optimal Complexity of Adaptive Finite Element Methods
Lianhua He,Aihui Zhou
Mathematics , 2010,
Abstract: In this paper, we study adaptive finite element approximations in a perturbation framework, which makes use of the existing adaptive finite element analysis of a linear symmetric elliptic problem. We prove the convergence and complexity of adaptive finite element methods for a class of elliptic partial differential equations. For illustration, we apply the general approach to obtain the convergence and complexity of adaptive finite element methods for a nonsymmetric problem, a nonlinear problem as well as an unbounded coefficient eigenvalue problem.
Normal property, Jamenson property, CHIP and linear regularity for an infinite system of convex sets in Banach spaces
Zhou Wei,Qinghai He
Mathematics , 2013,
Abstract: In this paper, we study different kinds of normal properties for infinite system of arbitrarily many convex sets in a Banach space and provide the dual characterization for the normal property in terms of the extended Jamenson property for arbitrarily many weak*-closed convex cones in the dual space. Then, we use the normal property and the extended Jamenson property to study CHIP, strong CHIP and linear regularity for the infinite case of arbitrarily many convex sets and establish equivalent relationship among these properties. In particular, we extend main results in [3] on normal property, Jamenson property, CHIP and linear regularity for finite system of convex sets in a Hilbert space to the infinite case of arbitrarily many convex sets in Banach space setting.
The Health Differences and Influencing Factors of Elderly in Urban and Rural Areas: Based on Data of CLHLS 2014  [PDF]
Mengling He, Jian Zhou
Advances in Applied Sociology (AASoci) , 2018, DOI: 10.4236/aasoci.2018.84016
Abstract: The health of the elderly has always been an important issue to China in recent years. Based on the 6729 samples of 2014 Chinese Longitudinal Healthy Longevity Survey (CLHLS), this paper focuses on the health differences among the elderly in urban and rural China. The results show that: the health status of urban and rural elderly in China has significant differences. The elderly in rural areas are healthier than urban. The health of the elderly is affected by many factors. Education, marriage, health insurance, quality of sleep, participation in social activities and exercise have a positive effect on the health of the elderly. Positive and optimistic older people are in better health. The health status of the elderly with children’s financial support is superior to that of the elderly without financial support. The health effects of caring for the elderly are the opposite of financial support.

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