Critical Fujita exponent for a fast diffusive equation with variable coefficients

Zhongping Li,Chunlai Mu,Wanjuan Du 대한수학회 2013 대한수학회보 Vol.50 No.1

Abstract. In this paper, we consider the positive solution to a Cauchy problem in RN of the fast diffusive equation: [수식], with nontrivial, nonnegative initial data. Here [수식}. We prove that [수식] is the critical Fujita exponent. That is, if 1 < q ≤ qc, then every positive solution blows up in finite time, but for q > qc, there exist both global and non-global solutions to the problem.

Heuristic Grid Resource Scheduling Algorithm based on Group of Task and Secondary Distribution

Zhongping Zhang,Yupeng Feng,Shan Zhang,Ying Sun 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.8

Grid resource scheduling policies directly affect the performance of the grid, so the grid resource scheduling algorithm for grid research has become a hot spot. In this paper, based on grid heterogeneity to resource scheduling of load balancing, effective resource utilization and minimize task sets the span of time (Makespan) as the goal, propose a heuristic grid resource scheduling algorithm based on Group of Task and Secondary Distribution, the basic idea is dividing the set of tasks into two groups by using the standard deviation, the one is long tasks group, another is short tasks group .The longest task in long tasks group will be allocated to the worst performance to execute, the rest can be done in the same manner. Tasks in short tasks group will be executed by the Min-Min algorithm , and then through secondary dispatch ideas to make the grid system to quickly reach each resource load balancing , improving resource utilization efficiency and minimizing the task set time span. Finally, the simulation model benchmark Braun et al. demonstrates the effectiveness of the algorithm.

Preparation of NiO and CoO nanoparticles using M2+-oleate (M = NiCo) as precursor

Zhongping Chen,Aiqun Xu,Yu Zhang,Ning Gu 한국물리학회 2010 Current Applied Physics Vol.10 No.3

The preparation of NiO and CoO nanoparticles was reported. The dot-like NiO and flower-like CoO nanoparticles were obtained using M2+-oleate (M = Ni, Co) as precursor via thermal decomposition method. Transmission electron microscopic (TEM) images monitored the growth of NiO and CoO nanoparticles. When the reaction complex including M2+-oleate (M = Ni, Co) precursor, oleic acid and 1-octadecene was heated to the refluxing temperature (320 ℃), the formed NiO and CoO nanoparticles were needlelike and very small, indicating low growth speed. However, when the reaction complex was kept refluxing for 30 min, dot-like NiO and flower-like CoO nanoparticles were observed, suggesting the accelerated growth at this refluxing stage. The difference of the morphology of the resultant NiO and CoO nanoparticles resulted from the difference of their growth mode. Selected-area electron diffraction (SAED) patterns showed the face-centered cubic structures of NiO and CoO nanoparticles. The magnetic property of the nanoparticles was studied using vibrating sample magnetometer (VSM).

30 Li+-accommodating covalent organic frameworks as ultralong cyclable high-capacity Li-ion battery electrodes

( Zhongping Li ),이상영 한국공업화학회 2022 한국공업화학회 연구논문 초록집 Vol.2022 No.-

Growth and Triterpenic Acid Accumulation of Cyclocarya paliurus Cell Suspension Cultures

Zhongping Yin,Xinchen Shangguan,Jiguang Chen,Qiang Zhao,Dongming Li 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.3

Cyclocarya paliurus is a unique plant growing in central China with hypoglycaemic and hypolipaemia effects. To make better use of this functional food resource,cell suspension cultures and triterpenic acid accumulation were studied. Stable and uniform cell suspension cultures were established in liquid basal Murashige and Skoog medium supplemented with 2,4-dichlorophenoxy acetic acid (0.5 mg/L), naphthalene acetic acid (0.3 mg/L) and cytokinin (1.0 mg/L). According to the growth curve and triterpenic acid accumulation curve, the 8 ~ 10th day postinoculation was the optimum time for subculture, and the 14th day was the optimum time for harvest. Murashige and Skoog medium and woody plant medium were suitable for both cell growth and triterpenic acid accumulation. 3%sucrose (w/v), 60 mM total nitrogen (NO3-/NH4+ = 2/1),1.25 mM KH2PO4, 2 mM CaCl2, and 2 mM MgSO4 were all found to be fit for cell growth and triterpenic acid accumulation in a cell suspension culture of Cyclocarya paliurus. Total triterpenic acid, ursolic acid and oleanolic acid content in suspended cultured cells were all significantly higher than that of leaves and calluses (P 0.01), with levels up to 6.24, 2.28, and 0.94% (of dry weight), respectively. The betulinic acid content of suspended cultured cells also reached 0.82%, which was significantly higher than that of calluses. These results suggest that suspended cultured cells of Cyclocarya paliurus were rich in triterpenic acids and could be used for the production of total triterpenic acid, ursolic acid, oleanolic acid and betulinic acid.

Microstructure Selection in the Interdendritic Region During Directional Solidification of a Ni-23at.%Al Alloy

Zhongping Que,Jiho Gu,Jongho Shin,정연길,Jehyun Lee 대한금속·재료학회 2014 METALS AND MATERIALS International Vol.20 No.1

Directional solidification experiments of a binary Ni-23at.%Al alloy were carried out to examine the effectsof growth velocity on the microstructure selection in the interdendritic region. Only the growth velocity waschanged from 5 µm/s to 60 µm/s under a given thermal gradient. As a result, the noticeable change in themicrostructure during solidification occurred between the γ dendrites. The γ interdendritic microstructure wasvaried as a function of growth velocity from rod γ-γ' coupled peritectic structure to planar γ' structure andthen to eutectic structures consisting of stable γ'-β eutectic and metastable γ-β‚ eutectic structures. Themicrostructure selected preferentially among the γ dendrites was considered by calculating the interfacetemperature of a phase growing into its parent melt. It is shown that the microstructure selection in the γinterdendritic region is determined by a phase or a structure kinetically leading at the highest interfacetemperature under a given growth condition.

Impact of Multiple Satellite Ocean Color Samplings in a Day on Assessing Phytoplankton Dynamics

ZhongPing Lee,Mingshun Jiang,Curtiss Davis,Nima Pahlevan,안유환,Ronghua Ma 한국해양과학기술원 2012 Ocean science journal Vol.47 No.3

Ocean-color imagers on conventional polar-orbiting satellites have a revisit time of ~2 days for most regions, which is further reduced if the area is frequently cloudy. The Geostationary Ocean Color Imager (GOCI), the first ocean-color imager on a geostationary satellite, provides measurements 8times a day, thus significantly improving the frequency of measurements for studies of ocean environments. Here, we use results derived from GOCI measurements over Taihu Lake to demonstrate that the extra sampling can be used to improve the accuracy of statistically averaged longer-term (daily) measurements. Additionally, using numerical simulations, we demonstrate that the coupling of diurnal variations of both biomass and photosynthetic available radiation can improve the accuracy of daily primary production estimates. These results echo that higher sampling frequency can improve our estimates of longer-term dynamics of biogeochemical processes and highlights the value of ocean color measurements from geostationary satellites.

CRITICAL FUJITA EXPONENT FOR A FAST DIFFUSIVE EQUATION WITH VARIABLE COEFFICIENTS

Li, Zhongping,Mu, Chunlai,Du, Wanjuan Korean Mathematical Society 2013 대한수학회보 Vol.50 No.1

In this paper, we consider the positive solution to a Cauchy problem in $\mathbb{B}^N$ of the fast diffusive equation: ${\mid}x{\mid}^mu_t={div}(\mid{\nabla}u{\mid}^{p-2}{\nabla}u)+{\mid}x{\mid}^nu^q$, with nontrivial, nonnegative initial data. Here $\frac{2N+m}{N+m+1}$ < $p$ < 2, $q$ > 1 and 0 < $m{\leq}n$ < $qm+N(q-1)$. We prove that $q_c=p-1{\frac{p+n}{N+m}}$ is the critical Fujita exponent. That is, if 1 < $q{\leq}q_c$, then every positive solution blows up in finite time, but for $q$ > $q_c$, there exist both global and non-global solutions to the problem.

Non-iterative Global Mesh Smoothing with Feature Preservation

Ji, Zhongping,Liu, Ligang,Wang, Guojin Society for Computational Design and Engineering 2006 International Journal of CAD/CAM Vol.6 No.1

This paper presents a novel approach for non-iterative surface smoothing with feature preservation on arbitrary meshes. Laplacian operator is performed in a global way over the mesh. The surface smoothing is formulated as a quadratic optimization problem, which is easily solved by a sparse linear system. The cost function to be optimized penalizes deviations from the global Laplacian operator while maintaining the overall shape of the original mesh. The features of the original mesh can be preserved by adding feature constraints and barycenter constraints in the system. Our approach is simple and fast, and does not cause surface shrinkage and distortion. Many experimental results are presented to show the applicability and flexibility of the approach.

Removal of surface-reflected light for the measurement of remote-sensing reflectance from an above-surface platform

Lee, ZhongPing,Ahn, Yu-Hwan,Mobley, Curtis,Arnone, Robert The Optical Society 2010 Optics express Vol.18 No.25

<P>Using hyperspectral measurements made in the field, we show that the effective sea-surface reflectance ? (defined as the ratio of the surface-reflected radiance at the specular direction corresponding to the downwelling sky radiance from one direction) varies not only for different measurement scans, but also can differ by a factor of 8 between 400 nm and 800 nm for the same scan. This means that the derived water-leaving radiance (or remote-sensing reflectance) can be highly inaccurate if a spectrally constant ? value is applied (although errors can be reduced by carefully filtering measured raw data). To remove surface-reflected light in field measurements of remote sensing reflectance, a spectral optimization approach was applied, with results compared with those from remote-sensing models and from direct measurements. The agreement from different determinations suggests that reasonable results for remote sensing reflectance of clear blue water to turbid brown water are obtainable from above-surface measurements, even under conditions of high waves.</P>