In this paper,we prove an explicit formula of the heat kernel on the circle.As a consequence,we establish the monotonicity of the heat kernel.It is well known that the heat kernel can be viewed as the transition proba...In this paper,we prove an explicit formula of the heat kernel on the circle.As a consequence,we establish the monotonicity of the heat kernel.It is well known that the heat kernel can be viewed as the transition probability of random walk on graphs.We also give the definition of the simple lazy random walk on graphs.The transition probabilities of simple lazy random walk on Z and cycle are derived.展开更多
The presented research was focused on a comparison between different means of obtaining a Nusselt number distribution,in a situation where neither temperature nor heat flux density is constant.Two fundamentally differ...The presented research was focused on a comparison between different means of obtaining a Nusselt number distribution,in a situation where neither temperature nor heat flux density is constant.Two fundamentally different measurement techniques have been utilized,alongside a CFD simulation,in order to designate temperature distributions in a horizontal rod.Dry air under normal pressure,regarded as a perfect gas,was chosen as the working fluid,whereas the rod's cross-section was restricted to a ring.In this scenario heat exchange between the rod and the fluid is driven predominantly by natural convection,with a slight impact of thermal radiation,particularly at temperatures approaching the top end of the available range.Temperature margins achieved at the heated end of the rod ranged from 60 K up to 150 K,resulting in local Rayleigh numbers falling in-between 6.0xl03 and 2.6xl04.Reconstruction of Nusselt numbers from a discrete temperature distribution was possible thanks to a dedicated method implemented using a Scilab script.A segregated,steady-state solver based on the SIMPLE scheme was utilized for the purpose of numerical simulations on the fluid side,whereas a heat conduction equation was solved over solid domain in the considered conjugated heat transfer problem.A corresponding set of empirical data has been obtained,using both resistance temperature detectors and a thermal imaging camera,both for the sake of numerical model validation and comparison of individual methods.The Nusselt numbers resulting from each approach were compared against values computed using available correlations valid for horizontal configuration.展开更多
A water-soluble polyhydroxylated fullerene, i.e., a fullerenol, with 44 hydroxyl groups and 8 secondary bound water molecules, C60（OH）44·8H2O （estimated average structure）, has been synthesized in a facile on...A water-soluble polyhydroxylated fullerene, i.e., a fullerenol, with 44 hydroxyl groups and 8 secondary bound water molecules, C60（OH）44·8H2O （estimated average structure）, has been synthesized in a facile one step reaction from pristine C60 by hydroxylation with hydrogen peroxide in the presence of a phase-transfer catalyst, tetra-n-butylammonium hydroxide （TBAH）, under organic/aqueous bilayer conditions. The fullerenol exhibited high water solubility, up to 64.9 mg/mL, under neutral （pH = 7） conditions. Dynamic light-scattering （DES） analysis showed a narrow particle size distribution, of 1-2 nm, indicating that the fullerenol had high dispersion properties in water. The results of particle size analyses, which botll focused on a single nanoregion and were conducted using a novel induced grating （IG） method and a scanning probe microscope （SPM）, were consistent with the DES results. A plausible reaction mechanism, which includes fullerene oxide intermediates detected by liquid chromatography-mass spectrometry （LC-MS）, has been proposed.展开更多
Effective and robust recognition and tracking of objects are the key problems in visual surveillance systems. Most existing object recognition methods were designed with particular objects in mind. This study presents...Effective and robust recognition and tracking of objects are the key problems in visual surveillance systems. Most existing object recognition methods were designed with particular objects in mind. This study presents a general moving objects recognition method using global features of targets. Targets are extracted with an adaptive Gaussian mixture model and their silhouette images are captured and unified. A new objects silhouette database is built to provide abundant samples to train the subspace feature. This database is more convincing than the previous ones. A more effective dimension reduction method based on graph embedding is used to obtain the projection eigenvector. In our experiments, we show the effective performance of our method in addressing the moving objects recognition problem and its superiority compared with the previous methods.展开更多
基金Supported by NSFC (Nos.10671182,12061020)NSF of Guizhou Province (Nos.QKH[2019]1123,QKHKY[2021]088,QKHKY[2022]301,QKH-ZK[2021]331)Ph.D. Project of Guizhou Education University (No.2021BS005)。
文摘In this paper,we prove an explicit formula of the heat kernel on the circle.As a consequence,we establish the monotonicity of the heat kernel.It is well known that the heat kernel can be viewed as the transition probability of random walk on graphs.We also give the definition of the simple lazy random walk on graphs.The transition probabilities of simple lazy random walk on Z and cycle are derived.
文摘The presented research was focused on a comparison between different means of obtaining a Nusselt number distribution,in a situation where neither temperature nor heat flux density is constant.Two fundamentally different measurement techniques have been utilized,alongside a CFD simulation,in order to designate temperature distributions in a horizontal rod.Dry air under normal pressure,regarded as a perfect gas,was chosen as the working fluid,whereas the rod's cross-section was restricted to a ring.In this scenario heat exchange between the rod and the fluid is driven predominantly by natural convection,with a slight impact of thermal radiation,particularly at temperatures approaching the top end of the available range.Temperature margins achieved at the heated end of the rod ranged from 60 K up to 150 K,resulting in local Rayleigh numbers falling in-between 6.0xl03 and 2.6xl04.Reconstruction of Nusselt numbers from a discrete temperature distribution was possible thanks to a dedicated method implemented using a Scilab script.A segregated,steady-state solver based on the SIMPLE scheme was utilized for the purpose of numerical simulations on the fluid side,whereas a heat conduction equation was solved over solid domain in the considered conjugated heat transfer problem.A corresponding set of empirical data has been obtained,using both resistance temperature detectors and a thermal imaging camera,both for the sake of numerical model validation and comparison of individual methods.The Nusselt numbers resulting from each approach were compared against values computed using available correlations valid for horizontal configuration.
文摘A water-soluble polyhydroxylated fullerene, i.e., a fullerenol, with 44 hydroxyl groups and 8 secondary bound water molecules, C60（OH）44·8H2O （estimated average structure）, has been synthesized in a facile one step reaction from pristine C60 by hydroxylation with hydrogen peroxide in the presence of a phase-transfer catalyst, tetra-n-butylammonium hydroxide （TBAH）, under organic/aqueous bilayer conditions. The fullerenol exhibited high water solubility, up to 64.9 mg/mL, under neutral （pH = 7） conditions. Dynamic light-scattering （DES） analysis showed a narrow particle size distribution, of 1-2 nm, indicating that the fullerenol had high dispersion properties in water. The results of particle size analyses, which botll focused on a single nanoregion and were conducted using a novel induced grating （IG） method and a scanning probe microscope （SPM）, were consistent with the DES results. A plausible reaction mechanism, which includes fullerene oxide intermediates detected by liquid chromatography-mass spectrometry （LC-MS）, has been proposed.
基金Project (No. 60805001) partially supported by the National NaturalScience Foundation of China
文摘Effective and robust recognition and tracking of objects are the key problems in visual surveillance systems. Most existing object recognition methods were designed with particular objects in mind. This study presents a general moving objects recognition method using global features of targets. Targets are extracted with an adaptive Gaussian mixture model and their silhouette images are captured and unified. A new objects silhouette database is built to provide abundant samples to train the subspace feature. This database is more convincing than the previous ones. A more effective dimension reduction method based on graph embedding is used to obtain the projection eigenvector. In our experiments, we show the effective performance of our method in addressing the moving objects recognition problem and its superiority compared with the previous methods.
