色散控制孤子系统的应用设计研究

对色散控制孤子(DMS)系统的设计展开研究,首次通过DMS系统的传输理论研究系统参数受限度,确定DMS传输系统的参数以及系统设计步骤,然后研究将DMS传输系统应用于一段实际的干线网络。作为优化设计DMS系统传输参数的例子,改建后的干线网的传输特性和眼图性能良好,基本上能得到理想的结果。为色散管理孤子方案应用于实际系统提供有价值的参考,为升级传统光纤线路,实现高速大容量传输提供有益的参考。     

一株新硫醇脱臭菌的降解机能研究

从多菌源经富集分离出一株高效降解硫醇臭气的菌株(JLL),通过16S rRNA基因序列分析法和传统的生理生化法相结合,鉴定JLL为黄杆菌属的新种。经洗涤法降解实验分析JLL对硫醇气体的降解机理,并对JLL采用碱裂解法未提出质粒,基本可以确定菌株JLL不含质粒,其降解基因在染色体上,降解过程为染色体控制。     

大功率柴油机管理系统的开发研究与应用

针对特种大功率柴油机,应用最新的微电子技术、控制技术和计算机软件技术开发设计了柴油机管理系统,通过合理地设计系统的结构,提高整个系统功能控制和参数管理的性能,最终使柴油机的经济性、动力性、排放等性能得以改善。在理论和试验应用的基础上,提出了大功率柴油机管理系统开发与设计的一般方法,为大功率柴油机管理系统的设计与应用提供了理论参考。     

A study on volatile organic sulfide causes of odors at Philadelphia's Northeast Water Pollution Control Plant

Volatile organic sulfide (VOS) causes of odors were studied at Philadelphia's Northeast Water Pollution Control Plant between September 11 and November 25, 2003. Results showed that dimethyl sulfide (DMS) dominated the VOS pool whenever VOS concentration rose above the background level (<50 microg/L). Methanethiol was generally less than 10% of VOS and it was mainly found at sites with limited or reduced dissolved oxygen (DO). Dimethyl disulfide occupied approximately 1% of the VOS and was often not detectable. Carbon disulfide was not detected. The concentrations of DMS varied by three orders of magnitude, ranging from <5 to 1260 microg/L. High concentrations of DMS, averaging 419 and ranging from <5 to 1000 microg/L, were generally found in return activated sludge. The DMS concentration in the primary effluent ranged from <5 to 729 microg/L and averaged 245 microg/L. Concentrations of DMS in the aeration tank (AT) with high DO were from <5 to 997 microg/L with an average of 250 microg/L. However, DMS concentrations in the AT representing anaerobic conditions were as high as 1260 microg/L. The estimated average purge efficiency of DMS was about 78%, which required a DMS production rate of 108 microg/Lh(-1) to keep the analyzed concentration in the AT. While a valid but weak statistical relationship between acetone and DMS was observed, there was no strong evidence to support that the methylation of hydrogen sulfide with acetone could be the mechanism for the DMS formation. Instead, DMS production was found to be associated with the characteristics of incoming wastewater. Thus, a VOS precursor was believed to be present in the incoming wastewater, which warranted a need for further investigation.     

海砂中氯离子含量的影响因素研究

试验研究了砂水比、海水氯离子含量、海砂含水率及颗粒粒径等因素对海砂中氯离子含量的影响.结果表明:海砂中氯离子含量分别与海水氯离子含量及海砂含水率显著线性相关;堆积状态下的海砂,其含水率沿堆积高度呈递减规律,含水率稳定值对应的临界高度约为40cm;海水氯离子含量、海砂含水率及颗粒粒径等因素对海砂氯离子含量的影响规律均可用相应的数学关系来表征.     

基于Web服务的电力企业实时信息应用集成

分析了电力企业实时应用各异构系统间难以共享信息的现状.基于Web服务技术设计了能提供业务服务、应用服务、客户服务和编制服务等多种服务的标准化的松耦合的一体化电力实时信息应用集成框架,应用Web服务提供通用基础架构支持,使用基于知识库的编制服务实现SCADA、EMS、DMS等实时应用系统间的实时信息互通和互操作.集成框架...     

Tunable optical,electronic and magnetic properties of semiconductor nanoparticles induced by magnetic and nonmagnetic dopants: A comparative experimental and theoretical study

While combining semiconductor and magnetic properties at the nanoscale provides dilute magnetic semiconductor (DMS) nanomaterials with a wide range of applications in next-generation electronic devices, tuning DMS properties still presents a challenge. Here, the synthesis of pure ZnO and transition metal (TM)-doped ZnO nanoparticles (NPs) with different magnetic (Fe and Co) and nonmagnetic (Mn) dopant concentrations (ranging from 2% to 10%) is reported using a co-precipitation method. Introducing the TM-dopants into ZnO NPs with 35?nm wurtzite structure causes crystallite and mean NP sizes to decrease, as characterized by X-ray diffraction and field-emission scanning electron microscopic analyses. Room-temperature magnetic measurements indicate coexistence of paramagnetic and ferromagnetic phases with tunability in the resulting TM-doped NPs. The maximum ferromagnetic coercivity and saturation magnetization are found to be 89?Oe and 0.074?emu/g for 10% Fe-doped ZnO NPs. UV–visible spectra showed a blue shift with increasing the dopant concentration, being in agreement with increasing trend in band gap energy calculated from band structure and density of state of TM-doped ZnO nanocrystal systems.     

EXAFS and SR-XRD study on Mn occupations in Zn1−xMnxO diluted magnetic semiconductors

Mn-doped ZnO films were prepared by radio frequency (RF) magnetron sputtering on sapphire substrate. Mn content was determined by proton induced X-ray emission (PIXE). Only Mn, no other magnetic impurities such as Fe, Co and Ni were observed. Also, no precipitates such as MnO, Mn₃O₄ and other secondary phases or Mn clusters, were found by SR-XRD, even in Mn-doped content up to 11 at.%. EXAFS analyses showed that Mn atoms were incorporated into ZnO crystal lattice by occupying the sites of zinc atoms.     

Effect of vacuum annealing and hydrogenation on ZnSe/Mn multilayer diluted magnetic semiconductor thin films

Multilayer thin films of ZnSe/Mn diluted magnetic semiconductor have been physically deposited onto a glass substrate using thermal evaporation technique and vacuum annealed at 333 K for 1 h at base pressure of 10⁻⁵ Torr. These thin films have been hydrogenated at different pressures (15-45 psi) for half an hour at room temperature. Hydrogenation process has been performed for as- grown as well as annealed thin films and named as-grown hydrogenated and annealed hydrogenated DMS thin films respectively. Structural characteristics of as-grown and vacuum annealed thin films have been performed by X-ray diffractometer. Current-voltage measurement has been studied for both as- grown hydrogenated and annealed hydrogenated DMS thin films by Keithly electrometer. X-ray diffraction pattern has been revealed nanocrystalline single phase of cubic zinc blende structure of film. Due to the annealing the conductivity has been found to be increased indicating the mixing of multilayer whereas the conductivity for as-grown hydrogenated and annealed hydrogenated ZnSe/Mn DMS thin films was found to be reduced indicating the electronic passivation effect of hydrogenation. Raman spectra of as-grown and annealed hydrogenated samples have been taken to see the presence of hydrogen in these samples. Surface topography of as-grown and annealed multilayer thin films has been confirmed by optical microscopy. Surface topography of annealed hydrogenated samples clearly shows the effect of hydrogenation at the surface.