Decentralized linear quadratic power system stabilizers for multi-machine power systems

Linear quadratic stabilizers are well-known for their superior control capabilities when compared to the conventional lead?Clag power system stabilizers. However, they have not seen much of practical importance as the state variables are generally not measurable; especially the generator rotor angle measurement is not available in most of the power plants. Full state feedback controllers require feedback of other machine states in a multi-machine power system and necessitate block diagonal structure constraints for decentralized implementation. This paper investigates the design of Linear Quadratic Power System Stabilizers using a recently proposed modified Heffron?CPhillip??s model. This model is derived by taking the secondary bus voltage of the step-up transformer as reference instead of the infinite bus. The state variables of this model can be obtained by local measurements. This model allows a coordinated linear quadratic control design in multi machine systems. The performance of the proposed controller has been evaluated on two widely used multi-machine power systems, 4 generator 10 bus and 10 generator 39 bus systems. It has been observed that the performance of the proposed controller is superior to that of the conventional Power System Stabilizers (PSS) over a wide range of operating and system conditions.     

从铜镉渣中回收锌、镉、铜试验研究

通过小型试验和工业试验,研究了一段浸出法从铜镉渣中浸出锌、镉、铜。试验结果表明:浸出体系中添加强氧化剂B可明显提高氧化速率和锌、镉浸出率,只需一段浸出,锌、镉浸出率均大于91%,且浸出液中杂质含量低,不需进一步除杂;铜不被浸出而是以海绵铜形式留在渣中,渣中铜质量分数为43%~46%,此渣可返回铜渣除氯系统循环利用。     

次氧化锌烟尘湿法冶炼系统体积平衡问题的研究

针对次氧化锌烟尘湿法冶炼系统的体积平衡难以控制的难题,本文以年处理次氧化锌烟尘6万t,产出电锌2万t的冶炼系统为例进行了体积平衡计算和分析,对冶炼企业的生产管理提供理论依据和技术指导。     

丁基钠黄药脱除银电解液中钯的研究

采用丁基钠黄药对含钯银电解液进行沉钯试验,沉钯后液进行银电解。结果表明,丁基钠黄药可以高效富集回收银电解液中的钯,在丁基钠黄药加入量为钯含量的3.6倍、70℃沉淀1h的最佳工艺条件下,沉钯率为99.84%,富集得到的钯精矿含钯12.19%,沉钯后液进行电解可以得到含钯达到IC-Ag99.99质量标准的产品。     

Stability of composite systems with an asymptotically hyperstable subsystem

In this note, it is proved that stability of composite systems including parallel subsystems can be achieved for certain sets of initial conditions and additional stability assumptions for the non-hyperstable subsystems. It is required that at least one subsystem be asymptotically hyperstable.     

Further Studies on the Formation of Nitrosamines in Cured Pork Products Packaged in Elastic Rubber Nettings

Traces of N-nitrosodi-n-butylamine (NDBA) and N-nitrosodiethylamine (NDEA) can form in cured pork products packaged in elastic rubber nettings due to the interaction of nitrite in meat and amines in the rubber. Studies were carried out to determine whether taking nettings off immediately after processing or placing a layer of collagen as a barrier between nettings and meat could prevent or minimize formation of the above nitrosamines. None was effective. However, cured pork products packaged in a reformulated rubber netting, made with different amine additives, contained either none or only negligible levels of NDBA or NDEA, but, instead, contained 8–104 ppb levels of a new nitrosamine, N-nitrosodibenzylamine which is reported to be noncarcinogenic.     

高铅氧化锌烟尘综合回收的生产实践与设计改进

以2.5万t/a高铅氧化锌烟尘综合回收项目为例,对其生产实践经验和设计改进进行总结,并提出重点对除氟氯和除砷锑工艺进行技术攻关,可为类似冶炼项目的设计和生产实践提供参考。     

一种分布式无线感应网定位算法研究

作为一种全新的信息获取和处理技术,无线传感器网络可以在广泛的应用领域内实现复杂的大规模监测和追踪任务,而网络自身定位是大多数应用的基础,本文提出一个分布式定位算法,可以在仅有一小部锚节点的无线感应网中动态定位全体节点,同时提出一些算法改进,可以有效的减少定位误差.     

蒙古语语言-文字的自动化处理

本文首先叙述了蒙文电子化的意义以及蒙文电子化数据的现状。然后重点讨论了在不同地区和国家使用的蒙文书面语以及口语的不同和蒙文在计算机处理时所面临的问题。最后,介绍了我们在日本建设的针对蒙古语语言信息处理的两种语言资源:蒙古语多方言口语语料库和蒙文多文种-多语言并行语法标注电子词典,后者得到了2005年中日蒙韩国际合作课题“蒙文自然语言处理技术的研究”的资助。     

Complexity of the diagnosability problem for a general model of diagnosable systems

The complexity of the diagnosability problem for a self-diagnosable system is analysed in this paper. The most commonly studied model (Preparata et al. 1967) for a diagnosable system has been analysed in the literature and a polynomial time algorithm for testing its diagnosability is known. This paper analyses a more general model of the diagnosable system and finds the diagnosability problem to be NP-hard. In this model, each unit is tested by several tests and each test is carried out jointly by several other units of the system as opposed to each test being carried out by a single unit as modelled by Preparata et al. (1967).