用于微波/射频集成电路的一种新型低损耗介质——多孔硅及氧化多孔硅厚膜

提出在单片微波集成电路(MMIC)中用多孔硅/氧化多孔硅厚膜作微波无源器件的低损耗介质膜.研究了厚度为70μm的多孔硅/氧化多孔硅厚膜在低阻硅衬底上的形成,这层厚膜增加了衬底的电阻率,减少了微波的有效介质损耗.通过测量在低阻硅衬底上形成的氧化多孔硅厚膜上的共平面波导的微波特性,证明了在低阻硅衬底上用厚膜氧化多孔硅可以提高共平面传输线(CPW)的微波特性.     

DO浓度对SUFR系统同步硝化反硝化的影响

采用螺旋升流式反应器（SUFR）处理生活污水，考察了好氧反应池中DO浓度对其同步硝化反硝化的影响。结果表明，在好氧反应池上部溶解氧浓度为3．0～3．5mg／L时，发生了明显的同步硝化反硝化现象，其对TN的去除量占SUFR系统对TN去除总量的16％左右；好氧反应池中的同步硝化反硝化反应只发生在池的下部，其中、上部只进行了好氧硝化反应；SUFR系统中好氧反应池上部的最佳溶解氧浓度范围为3．0～3．5mg／L，此时系统的硝化和反硝化效果最佳，好氧反应池中的脱氮效果也较好，系统对TN的去除率〉84％。     

A systematic data integration technique for mold-surface polishing processes planning

This paper presents a new MSDI (mold surface data integration) method for presenting ruled mold-surface data for CAPP applications. The method makes use of adjacency and feature-data matrices to establish a framework of feature-based data. The MSDI method enables the storage, retrieval and operations of geometries, topologies, and machining information of a given ruled mold surface. The matrices of adjacency and feature-data effectively represent the relations. Boolean algebra and group technology (GT) methods are introduced to generate the desired process plans. A sample mold made of ruled surfaces is made and used to show the effectiveness of the proposed data representation and the integrated mold surface processing method. A compact computer program is implemented to enhance the speed and accuracy of the MSDI method. The numerical results indicate that the mold surface decomposition and integration procedure presented in this paper are systematic and effective. The paper provides a novel modular mold surface modeling tool and procedure that can be further extended to accommodate more features appearing in complicated ruled mold surfaces.     

A Bluetooth Routing Protocol Using Evolving Fuzzy Neural Networks

In this paper, a routing protocol which utilizes the characteristics of Bluetooth technology is proposed for Bluetooth-based mobile ad hoc networks. The routing tables are maintained in the master devices and the routing zone radius for each table is adjusted dynamically by using evolving fuzzy neural networks. Observing there exists some useless routing packets which are helpless to build the routing path and increase the network loads in the existing ad hoc routing protocols, we selectively use multiple unicasts or one broadcast when the destination device is out of the routing zone radius coverage of the routing table. The simulation results show that the dynamic adjustment of the routing table size in each master device results in much less reply time of routing request, fewer request packets and useless packets compared with two representative protocols, Zone Routing Protocol and Dynamic Source Routing.     

Design and analysis of low-power cache using two-level filter scheme

Power consumption is an increasingly pressing problem in modern processor design. Since the on-chip caches usually consume a significant amount of power, it is one of the most attractive targets for power reduction. This paper presents a two-level filter scheme, which consists of the L1 and L2 filters, to reduce the power consumption of the on-chip cache. The main idea of the proposed scheme is motivated by the substantial unnecessary activities in conventional cache architecture. We use a single block buffer as the L1 filter to eliminate the unnecessary cache accesses. In the L2 filter, we then propose a new sentry-tag architecture to further filter out the unnecessary way activities in case of the L1 filter miss. We use SimpleScalar to simulate the SPEC2000 benchmarks and perform the HSPICE simulations to evaluate the proposed architecture. Experimental results show that the two-level filter scheme can effectively reduce the cache power consumption by eliminating most unnecessary cache activities, while the compromise of system performance is negligible. Compared to a conventional instruction cache (32 kB, two-way) implemented with only the L1 filter, the use of a two-level filter can result in roughly 30% reduction in total cache power consumption. Similarly, compared to a conventional data cache (32 kB, four-way) implemented with only the L1 filter, the total cache power reduction is approximately 46%.     

Parameter evaluation in automated digital deep-level transientspectroscopy (DLTS)

A method of directly evaluating the activation energy ΔE, capture cross section σ, and density N_T, of deep-level traps from the pulsed reverse bias capacitance transient is described. The main advantages of this technique are that it requires only a single temperature scan, and it can resolve nonexponential transients due to closely-spaced energy levels. The test samples used for this paper consisted of Schottky diodes fabricated on nonirradiated and 1-MeV electron-irradiated n-type VPE (vapor-phase epitaxy) GaAs wafers. The well known EL2 trap was identified with ΔE of 0.81 eV, and σ _n of 1.0×10^-13 cm² for the nonirradiated sample. These values were found to be in good agreement with published data using established, conventional DLTS techniques. For the irradiated samples a nonexponential capacitance transient was found in the EL2 range of temperatures. The discussed technique was able to resolve two closely spaced deep levels lying at E_c-0.81 eV and E_c-0.84 eV, and with capture cross sections of 1.5×10^-13 cm² and 2.5×10^-12 cm², respectively     

A newly robust controller design for the position control ofpermanent-magnet synchronous motor

A robust controller which is designed by employing variable-structure control and linear-quadratic method is presented for a permanent-magnet synchronous motor (PMSM) position control system. It is to achieve accurate control performance in the presence of plant parameter variation and load disturbance. In addition, it possesses the design flexibility of the conventional state feedback control. It is applied to the position control of a PMSM. Simulation and experimental results show that the proposed approach gives a better position response and is robust to parameter variations and load disturbance     

Resonant snubber-based soft-switching inverters for electricpropulsion drives

This paper summarizes recently developed soft-switching inverters and proposes two possible options for electric propulsion motor drive applications. The newly developed soft-switching inverter employs an auxiliary switch and a resonant inductor per phase to produce a zero voltage across the main switch, so that the main switch can turn-on at the zero-voltage condition. Both the auxiliary switch and the resonant inductor are operating at a fractional duty and, thus, are small in size as compared to the main inverter circuit components. Operation modes in a complete zero-voltage switching cycle for the single-phase soft-switching inverter are described in detail, with graphical explanations. The circuit operation was first verified by a computer simulation, and then further tested with a 1 kW single-phase and a 100 kW three-phase inverter. Both simulation and experimental results are presented to show the superior performance in efficiency improvement, EMI reduction and dv/dt reduction of the proposed soft-switching inverters