08 January 2011, Volume 29 Issue 11-01

    

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  Steric Effects on the Enhanced Oxygen Storage Capacity of Ni Point Defects in Ceria: A First-principles DFT+U Study

  . 2011, 29(11-01): 26-29. https://doi.org/10.3981/j.issn.1000-7857.2011.01.001

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  First-principles density functional theory calculations with the inclusion of on-site Coulomb interaction for the Ce4f and Ni3d electrons (DFT+U) are used to study the effects on the atomistic structures induced by the doping of bulk ceria (CeO2) with Ni atoms at substitutional (S) and interstitial (I) lattice sites. It has been found that for Ce0.97Ni0.03O2-S system, the local structure around dopant possesses octahedral symmetry and expands after the formation of oxygen vacancy; while for Ce0.97Ni0.03O2-I system, the local structure around dopant possesses tetrahedral symmetry and shrinks after the formation of oxygen vacancy. Furthermore, based on the analysis of global displacement, it has been found that the atomic relaxation has been accomplished before the formation of oxygen vacancy for Ce0.97Ni0.03O2-S system, which indicates the possibility of simultaneous formation of the oxygen vacancies around substitutional dopant sites.
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  Temporal and Spatial Characteristics of Extreme Temperature Events over Shandong Province During 1961—2008

  . 2011, 29(11-01): 30-35. https://doi.org/10.3981/j.issn.1000-7857.2011.01.002

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  Based on daily mean surface temperature data of 18 meteorological stations over Shandong province during 1961—2008, the thresholds of extreme high and low temperature events have been determined for each station by the centesimal value method, and then, the spatial characteristics and temporary trends of extreme temperature frequency for recent 48 years have been analyzed. The results show that there was a great spatial difference in both annual extreme high and low temperature frequency over Shandong Province and the highest frequency regions were mainly distributed in Jiaodong Peninsular. However, the difference values of annual extreme high and low temperature frequency in between high-value and low-value areas were all small and the mean annual extreme high and low temperature days were mostly 15~16d/a. Whether at the annual or seasonal scales, there was an increasing trend in extreme high temperature frequency, which was most significant in spring, while there was a decreasing trend in extreme low temperature frequency, which was most marked in winter. Annual changes in extreme high and low temperature frequency show obvious spatial variations, which were more remarkable in Jiaodong Peninsular in contrast to the west of Shandong Province. For recent 48 years, the abruptions in the annual time series of extreme high and low temperature frequency were found in all stations but Haiyang Station for extreme high temperature frequency and their trends were more significant since 1990s. In addition, fluctuation changes were found in annual extreme high and low temperature frequency with a quasi-5-year period.
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  Seepage Characteristics and Influencing Factors in Ultra-low Permeability Reservoirs

  . 2011, 29(11-01): 36-39. https://doi.org/10.3981/j.issn.1000-7857.2011.01.003

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  In order to study seepage characteristics and influencing factors in ultra-low permeability reservoirs, with samples taken from Ordos, experiments of single phase flow and oil-water phase flow were conducted. The results indicate there exists a threshold pressure gradient for single phase flows for part of samples. The flow is of non-darcy seepage when the pressure gradient is low and it changes into darcy flow at high pressure; but for other samples, no obvious non-darcy flow is found. The lower the core permeability is, the higher the pressure under which non-Darcy state will retain and less the flow volume will be. The flow curve for the core is not a straight line but a curve protruding to the shearing stress axis. The fluid is non-Newtonian and fake plastic fluid, which does not move besides some elastic deformation under a weak external force, and which moves under a strong external force, with an obvious yield stress. The relation between moving shearing stress and permeability indicates that the shearing stress decreases rapidly with the decrease of permeability. The apparent viscosity reduces slowly when the shearing rate increases The density of the fluid decreases after shearing. Irreducible water saturation and residual oil saturation become high and the two-phase region becomes narrow under the condition of two-phase seepage. The relative permeability value of oil-phase reduces quickly and the water-phase increases slowly with the increase of water saturation. The permeability, wettability and water-lock influence the seepage characteristics.
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  Structural Dynamical Response of Projectile-based Equipment Under High Overload

  . 2011, 29(11-01): 40-43. https://doi.org/10.3981/j.issn.1000-7857.2011.01.004

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  The design of a projectile-based equipment against high overload is very difficult in the context of the new-type information based ammunition design, and is one of the primary bottlenecks in the information based development of shells. At present, methods are usually adopted to simplify the system of the launching load and the load-relieving structure into a linear system to deal with the problem of Projectile-loaded Equipments against high overload; the results are not satisfactory as compared with the test results. According to the actual launching load and the nonlinear characteristics of load-relieving structure materials, based on a one-dimensional dynamical model in the strong shock condition, the load curve and the force-displacement curve of the load-relieving structure using material's mechanical experiment are obtained by curve fitting from data obtained by numerical simulations. The computational models of relative displacement and relative acceleration of the projectile-based equipment can be calculated using a precise integration method. With a certain special type shell as an example, the dynamic response of the projectile-based equipment is calculated, experiment results have verified the calculation results, and therefore, the research methods can provide a theoretical reference for the design of projectile-based equipment against high overload.
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  Key Technologies of Interactive Dynamic Volumetric 3D Display

  . 2011, 29(11-01): 44-51. https://doi.org/10.3981/j.issn.1000-7857.2011.01.005

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  Key technologies of dynamic Volumetric Three-Dimensional (V3D) display is implemented in our prototype, which include 3D data voxelization, voxel activation, volumetric space creation, and human-computer interface, where 3D models are voxelized through Body-Cubic Center (BCC) sampling strategy for data reduction. Digital Micro-mirror Device (DMD) is used as the Spatial Light Modulator (SLM) and an algorithm is designed for binary slice projection based on DMD. An approach for volumetric space creation based on a rotating helical screen is also adopted. Furthermore, a hand gesture control-based HCI subsystem for the prototype is designed and implemented. Experimental results demonstrate that, a data reduction of more than 40% is achieved through utilizing BCC sampling strategy, and objects can be displayed with true three dimensions at a refresh rate of 16Hz in a half-cylinder display space with a diameter of 500mm and a height of 250mm, and can be viewed from almost any angle without any special viewing aids. With the hand gesture control subsystem, the average recognition rate is as high as 93%, the average response time is less than 40ms, and the real-time interactions can be well performed from an arbitrary viewpoint.
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  Fog Image Clearness Algorithm Based on the Fuzzy Contrast

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  . 2011, 29(11-01): 52-54. https://doi.org/10.3981/j.issn.1000-7857.2011.01.006

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  There are some shortcomings for the fog fuzzy image, such as the low contrast, blurred, and poor effects after the mathematical morphological enhancement. A new image clearness algorithm based on the fuzzy contrast and mathematical morphology is described. Using the previous fuzzy contrast enhancement algorithm, a new fuzzy membership function is defined, the image is changed from spatial domain into fuzzy field directly through it; therefore a fuzzy feature plane is obtained. In the fuzzy feature plane, the image could be enhanced. Lately, the image is taken back to its spatial domain. Then it is combined with the top-hat transform and bottom-hat transform of mathematical morphology pre-treatment. Finally, the enhanced image is obtained. An experiment for the fog image is presented. The results show that the algorithm has higher contrast and better visual effects. It is quite obvious that the algorithm is able to raise the contrast at the border and background and improve visual effects. In the other hand, this algorithm is good at making fuzzy image details become clearer, the noise is also suppressed, and there is no over enhancement, particularly in the sky area. Therefore, the proposed algorithm is an effective algorithm to clear fog image.
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  Determination of Contents of Rutin and Quercetin in Onion by Automated Pressurized Liquid Extractor and High Performance Liquid Chromatography

  . 2011, 29(11-01): 55-58. https://doi.org/10.3981/j.issn.1000-7857.2011.01.007

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  As compared with the water circumfluence method, a simple and rapid method was developed for the determination of contents of rutin and quercetin in onion by Automated Pressurized Liquid Extractor (APLE). The contents of rutin and quercetin were first determined by High Performance Liquid Chromatography (HPLC) in 368nm and analyzed on the C18 column by a isocratic elution, using a mixture of methanol-phosphoric acid solution(58:42, V/V) as the mobile phase with a flow rate of 1.0mL/min. The method is calibrated by an external standard method. Under the optimal conditions, the correlation coefficient of rutin and quercetin in the concentration range of 0.1~200mg/L is more than 0.999. The average recovery rates of rutin and quercetin in the spiked range of 2.0~100mg/kg are 83.5%~94.2% and 84.8%~91.2%, respectively. And the relative standard deviations are 2.9%~7.4% and 4.2%~6.9%, respectively (n=6). Using the automated pressurized liquid extractor method, the detection limit (LOD) of rutin and quercetin are 0.05mg/kg and 0.03mg/kg, respectively, and the quantitative limits (LOQ) of rutin and quercetin are 0.2mg/kg and 0.1mg/kg, respectively. Therefore, the method developed for the determination of rutin and quercetin in onion by automated pressurized liquid extractor and high performance liquid chromatography gives a good linearity, repeatability and high sensitivity, and is suitable for the rapid determination of rutin and quercetin in vegetables and fruits.
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  Synthesis of 1,2-O-propylidene-3-O-(2-methyl-2-penetenacyl)-5-O-benzoyl-D-xylofuranose and Its Flavoring in Cigarette

  . 2011, 29(11-01): 59-65. https://doi.org/10.3981/j.issn.1000-7857.2011.01.008

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  The compound 1,2-O-propylidene-3-O-(2-methyl-2-penetenacyl)-5-O-benzoyl-D-xylofuranose was synthesized from xylose, benzoyl chloride and 2-methyl-2-pentenoicacid with 4-DMAP as catalyst and DCC as dehydration reagent. Its structure was confirmed by IR, 1H NMR, HRMS spectra. The pyrolysis of the precursor and the application of the compound in blended cigarette flavoring were studied as well. The results show that: (1) The target compound can be synthetized in simpler operation and with higher yield.
  (2) Temperature has a great influence on the types and contents of pyrolysis of the compound; with the rise of pyrolytic temperature the cracking degree becomes more and more severe. The contents of furan, myrcene, 2-methyl-2-pentenoicacid and so on are higher in each temperature section. (3) When the dosage of the synthesized compound falls in the range of 0.004%～0.008%, the compound is in harmony with tobacco, and can improve aroma quality, enhance aroma quantity, reduce irritancy and improve aftertaste of cigarette smoke. Meanwhile a slight difference shows between tobacco from different areas in the requirement of the optimum additive amount of this compound.
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  Outline of Astrobiology

  YILIANG LI

  . 2011, 29(11-01): 66-74. https://doi.org/10.3981/j.issn.1000-7857.2011.01.009

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  Are we alone? Is our Earth, the tiny blue planet in this infinite Universe, the only harbor for life? Astrobiology concerns the study of the origin, evolution and destiny of life in the Universe and touches almost all the fundamental questions asked by mankind. The emergence of this science is the natural outcome of the great advances in astronomy, biology, and geology. The development of molecular biology has revealed the unitary origin and DNA-coding of all life on Earth in despite of the great diversity after a long Darwinian evolution. Geologists dated the origin of life back to almost 3.8 billion years ago. Planetary explorations in our solar system have indicated abundant life materials being stored in the planetesimal zone and beyond. Furthermore, the detection of exoplanets has practically extended life exploration into the deep Universe. The astrobiological studies can be classified into cosmic, planetary, ecosystematic scales on a space dimension and stellar and interstellar evolution, chemical evolution of prelife on Earth, and modern ecosystem on a time dimension. Stellar nucleosynthesis and the evolution of galactic chemistry tell us about the formation of life-essential elements, such as H-C-O-N-S-P and Fe-peaked transition metals. The breakthrough in exoplanet detection is a great step in searching a second life and scientists began to develop techniques to examine the atmosphere composition of Earth-like exoplanets. Based on our understanding of life origin on Earth, a body of liquid water, enough carbon and a silicate crust on a planet with a right distance to its sun are sufficient premises to make a planet habitable. When those conditions are met, life might start in hundred million years or even shorter time period. It is understood now that life deeply changes the surface spheres of Earth and our current atmosphere is pretty much the result of biological respiration. It is also wondered that the great events happened on Earth, such as the appearance of free oxygen, the starting of plate tectonics, the appearance of ice ages, planet-wide formation of banded iron may have either stimulated the evolution of life, or on the contrary, resulted in mass extinction. Now mankind is on a fast lane going forward but has a quite unpredictable future. How long can our Gaia last? Can our offspring find another oasis in the Universe? Astrobiology can not answer these questions now but they remain for exploration.
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  Index System of Viticultural Climatic Zoning in China

  . 2011, 29(11-01): 75-79. https://doi.org/10.3981/j.issn.1000-7857.2011.01.010

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  On the basis of summarizing all of main index systems of viticultural climatic zoning in China, all of current internal index systems of grapevine climatic cultivation are compared and analyzed from the climatic background, climatic zoning areas, means, and results. It deems that the major external indexes in grapevine cultivation, hydrothermal coefficient, accumulated temperature, level division-temperature index, heliothermal index, hypothermal coefficient ,etc, referred by internal experts are not suitable for all zoning of China. It also believes that only when establishing the new index system which has considered Chinese own geography and climate, the other analysis methods could embody their potential. It still reckons that the new cultivation system (frost-free period, dryness index, and bury line), founded by Li Hua et al is the first one regarding Chinese own climate features at present. Moreover, there are three problems: Firstly, the choice of indexes could not consider Chinese climate; Secondly, all the climatic zoning of viticulture are always from one theory to another theory, never go deep into the practice in order to verify their reliability; Thirdly, there is never a integral viticulture zoning which not only reaches entire country, but also goes into details on every areas. While the problems existing in the climatic zoning system for viticulture are indicated, the development trend of grapevine climatic zoning in China is also predicted. At last, some suggestions on climatic zoning in China are proposed. Based on the comparative analysis, a theoretical foundation of improvement and unity of indexes system of viticulture zoning in China is provided.