Effect of the implantation of fluorine on the mobility of channel electron for partially depleted SOI nMOSFET

The mobility of channel electron, for partially depleted Sol nMOSFET in this paper, decreases with the increase of implanted fluorine dose in buried oxide layer. But, the experimental results also show that it is larger for the transistor corresponding to the lowest implantation dose than no implanted fluorine in buried layer. It is explained in tern-is of a "lubricant" model. Mien fluorine atoms are implanted in the top silicon layer, the mobility is the largest. In addition, a positive shift of threshold voltage has also been observed for the transistors fabricated on the Sol wafers processed by the implantation of fluorine. The causes of all the above results are discussed.

HFFT算法的大规模集群性能评估及基于CUDA的并行化探索

近些年来，随着计算机硬件技术的高速发展，大规模并行集群系统被越来越多地用于各种科研应用等活动中，而随着多核CPU芯片的技术成熟，多核集群系统对于科学计算的处理能力得到了空前的提高，如何对科学计算中海量数据进行高效地并行计算，评估影响算法性能的相应因素，成为了一个很重要的研究方向。 快速傅立叶变换作为上个世纪公认的最重要的基础算法之一，在包括大规模科学计算处理，数字信号处理，图形图像仿真等众多领域有着广泛的应用，对此，本文结合了2008年中国最快的超级计算机曙光5000A与大规模非规则区域上的快速傅立叶变换算法，深入研究分析了该算法应用在超大规模多核并行环境下的可扩展性测试及影响性能的因素。测试结果表明，该算法在现有的超大规模并行环境下具有较好的性能，在曙光5000A上，算法在8192核的加速比达到了277倍。 本文的另一部分研究工作集中在探索现有HFFT算法在GPGPU上的并行化应用。GPU在处理能力和存储器带宽上相对CPU有明显优势，在成本和功耗上也不需要付出太大代价，这从而为并行数据处理问题提供了新的解决方案。由于图形渲染的高度并行性，使得GPU可以通过增加并行处理单元和存储器控制单元的方式提高处理能力和存储器带宽。 在实际应用中，Nvidia公司的CUDA是用于GPU计算的并行开发环境，是一个全新的软硬件架构，这个架构可以使用GPU来解决商业、工业以及科学方面的复杂计算问题。CUDA是一个完整的GPGPU解决方案，它提供了直接访问硬件的接口。由于目前GPU已在科研领域中得到广泛研究，为了利用GPU的并行数据处理能力，本文探索了一种通过GPU计算提高现有HFFT算法执行速度的途径。之后，本文对CUDA并行算法进行了实际测试，实验结果表明，GPU对并行FFT部分具有20%的加速比，而除去I/O传输后，程序的加速比是34.4倍。

安全网络数学计算协议

讨论了网络数学计算框架IAMC的安全性问题,给出了一个用安全协议SSL/TLS提高数学计算协议MCP安全性的实现方案.改进后的网络数学计算框架可有效地提供计算数据的机密性、完整性和用户认证等安全功能。

高效DOM实现的技术研究

DOM是目前为止唯一成为W3C正式标准的XML解析模型。本文充分考虑了DOM模型的特点,设计并实现了一个高性能的支持DOM的XML解析器OnceDOMParser。为了提高DOM实现的性能,我们采用用户堆提高对象管理的效率,减少对象在JVM中创建的数量,并采取了数据的延迟装载策略。OnceDOMParser经过了严格的XML兼容性测试和DOM API兼容性测试,多方面的性能测试表明OnceDOMParser性能优越,其平均吞吐量比目前最流行的XML解析器Xerces高43.7%左右。

用分子动力学模拟甲烷水合物热激法分解

用分子动力学模拟方法研究甲烷水合物热激法分解，系统地研究注入340 K液态水的结构Ⅰ型甲烷水合物的分解机理.模拟显示水合物表层水分子与高温液态水分子接触获得热能，分子运动激烈，摆脱水分子间的氢键束缚，笼状结构被破坏.甲烷分子获得热能从笼中挣脱，向外体系扩散.热能通过分子碰撞从外层传递给内层水分子，水合物逐层分解.对比注入277K液态水体系模拟结果，得出热激法促进水合物分解.

The methane hydrate formation and the resource estimate resulting from free gas migration in seeping seafloor hydrate stability zone

It is a typical multiphase flow process for hydrate formation in seeping seafloor sediments. Free gas can not only be present but also take part in formation of hydrate. The volume fraction of free gas in local pore of hydrate stable zone (HSZ) influences the formation of hydrate in seeping seafloor area, and methane flux determines the abundance and resource of hydrate-bearing reservoirs. In this paper, a multiphase flow model including water (dissolved methane and salt)-free gas hydrate has been established to describe this kind of flow-transfer-reaction process where there exists a large scale of free gas migration and transform in seafloor pore. In the order of three different scenarios, the conversions among permeability, capillary pressure, phase saturations and salinity along with the formation of hydrate have been deducted. Furthermore, the influence of four sorts of free gas saturations and three classes of methane fluxes on hydrate formation and the resource has also been analyzed and compared. Based on the rules drawn from the simulation, and combined information gotten from drills in field, the methane hydrate(MH) formation in Shenhu area of South China Sea has been forecasted. It has been speculated that there may breed a moderate methane flux below this seafloor HSZ. If the flux is about 0.5 kg m-2 a-1, then it will go on to evolve about 2700 ka until the hydrate saturation in pore will arrive its peak (about 75%). Approximately 1.47 109 m3 MH has been reckoned in this marine basin finally, is about 13 times over preliminary estimate.

Molecular Dynamics Simulation of Methane Hydrate Dissociation Process in the Presence of Thermodynamic Inhibitor

The dissociation of methane hydrate in the presence of ethylene glycol (11.45 mol.L-1) at 277.0 K was studied using canonical ensemble (NVT) molecular dynamics simulations. Results show that hydrate dissociation starts from the surface layer of the solid hydrate and then gradually expands to the internal layer. Thus, the solid structure gradually shrinks until it disappears. A distortion of the hydrate lattice structure occurs first and then the hydrate evolves from a fractured frame to a fractional fragment. Finally, water molecules in the hydrate construction exist in the liquid state. The inner dissociating layer is, additionally, coated by a liquid film formed from outer dissociated water molecules outside. This film inhibits the mass transfer performance of the inner molecules during the hydrate dissociation process.