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If we need to compute the NPMLE of a mixing distribution, which had been proved to be discrete with a finite support set in literature, some efficient and stable algorithms are desired. We propose several new algorithms, which are called partially projected gradient algorithms. These new algorithms can fully take advantage of the information provided by gradient functions. The numerical examples show they outperform the popular VEM algorithm and Wu's algorithms. ^ If we know the mixing distribution is continuous and intend to estimate the mixing density, then the NPMLE is not appropriate because it is a discrete distribution. The estimation of mixing densities is an ill-posed indirect estimation problem. In this dissertation, we apply the maximum penalized likelihood principle for estimating mixing densities, and derive a functional ...
In this thesis, I present a simple time-dependent model of heat transfer between a turbulently convecting and crystallizing magma body and the overlying hydrothermal circulation. Most of the known seafloor hydrothermal sites on faster-spreading ridges are dominated by basalt. The hydrothermal fields within parts of the Lau Basin in the Southwest Pacific are driven by andesitic magma. To determinate the different characteristics of magma-driven hydrothermal system, two types of magma material, basaltic and andesitic magma are considered. Two different crystallization scenarios are considered¡ªcrystals in suspension and crystals settling. In either case, I assume that large-scale convection within the magma chamber is homogenous. Also, the effect of crystallinity and water content-dependent magmatic viscosity is considered. Based on th...
Hydrothermal systems at oceanic spreading centers play an important role in the composition of seawater, the formation of ore deposits, the support of microbial and macrofaunal ecosystems, and even for the development of life on early earth. These circulation systems are driven by heat transport from the underlying magma chamber, where latent heat of crystallization and sensible heat from cooling are transferred by vigorous, high Rayleigh number convection through a thin conductive boundary layer. The traditional study of magmatic-hydrothermal systems is primarily based on the time-series observation, which takes the form of repeat visits, continuous offline monitoring by autonomous instruments, or continuous online monitoring by instruments with satellite or cable links to shore. Although a number of studies have deployed autonomou...
Comment: 7 pages, 4 figures, accepted by Chinese Journal of Astronomy and Astrophysics
A variety of experiments were carried out to study the dispersion and microstructure of carbon nanotubes in aqueous suspensions and polymer composites with the goal to improve the electrical conductivity of the composites containing nanotubes. Epoxy composites containing covalently and noncovalently functionalized nanotubes were compared in terms of electrical and mechanical behavior. Covalent functionalization of nanotubes is based on chemical attachments of polyethylenimine (PEI) whereas noncovalent functionalization takes place through physical mixing of nanotubes and PEI. The electrical conductivity is reduced in composites containing covalently functionalized nanotubes due to damage of the tube?s conjugated surface that reduces intrinsic conductivity. Conversely, the mechanical properties are always better for epoxy composites con...
In this computer era of rapid development, software development can be seen everywhere, but a lot of softwares are dead in modern development of software. Just as The Mythical Man-Month said, it exists a problem in the software development, and the problem is interflow.A lock of interflow can be said great calamity. Clustering is a environment to breed new life. In this thesis, we elaborate how P2N can be used to thinking, planning, developing, collaborating, releasing. And the approach that make your team and organization more perfect.
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