The Study of the Dynamic Thickness of Organic Boundary Films Under Metallic Sliding Contact

The paper herein proposes a method to simultaneously measure the friction, wear, and thickness of boundary films under a pure sliding contact between metallic surfaces. The method is based on the capacitance method used by Crook and Dyson et al. to measure elastohydrodynamic film thicknesses. Pilot tests conducted on sunflower oil using the new method showed an appreciable growth in the boundary film thickness, with a corresponding drop in the coefficient of friction. Very little wear was observed during the film growth. It is postulated that this growth was due to the polymerization of the unsaturated fatty acid chains.     

Distribution automation communication infrastructure

Communication is very important to distribution automation (DA) because DA relies on the coordinated effort of various elements in the system. Many communication systems have been designed for DA so far. However, most of these communication systems use proprietary (vendor specific) protocols and are for individual instead of all DA functions. Thus, there has long been a great need for an open and integrated communication system capable of supporting all DA functions transparently. This paper presents a new communication infrastructure, PS-TCP/IP (power system TCP/IP), for all DA communications including customer services. PS-TCP/IP can support all DA functions transparently because it follows three design principles. First, each network element (NE) involved in DA communications, including customer meters, is assigned a unique network-layer address which corresponds to their relative position in the power distribution network. Second, all NEs can communicate with each other as long as they encapsulate their data in a standard-format “IP datagram”. Third, any ISO layer 1 and 2 protocols can be incorporated easily. PS-TCP/IP's design follows ISO's layered approach. This means that the structure of the communication system is independent of that of any DA function's, thus creating a truly open and transparent communication environment for all DA functions     

Diffusivity of silver ions in the low temperature co-fired ceramic (LTCC) substrates

Diffusion of silver inner-electrode occurred during sintering of commercial low temperature co-fired glass ceramic substrate made the dielectric surface become light yellow. The samples added with silicon oxide (SiO₂) powder, however, maintained white color. Silicon-oxide powder was used to modified the sintering behavior and inhibit the silver ions diffusion for the LTCC ceramics. The alumina particles in the LTCC substrates could be regarded as the diffusion barrier of silver ions. The activation energy for silver ions diffusion in the LTCC substrates was 101 kJ/mol. When 5 wt% SiO₂ powder was added into the LTCC substrate, the diffusion activation energy of silver ions became 145 kJ/mol. At sintering temperature of 1180 K, the diffusion coefficient of silver ion in the LTCC ceramic substrates with and without additional SiO₂ were 8.88 × 10⁻¹³ cm²/s and 1.08 × 10⁻¹² cm²/s, respectively.     

Probabilistic packet marking with non-preemptive compensation

A new scheme in probabilistic packet marking (PPM) for IP traceback against denial-of-service attack is presented. Non-preemptive PPM is performed while a marked packet is coming, but compensates the reduction of marking probability in marked-free packets. The nonpreemptive compensation makes the probability of each marked packet arrived at the victim is equal to its original marking probability. This scheme efficiently improves the convergent amount of marked packets required for reconstructing the complete attack path.     

Phase Formation of Zinc Titanate Precursor Powders Prepared by a Hydrothermal Process in Various pH Environments

For the precursor, powders were calcined at 773 K (500 °C) for 1 hour. The anatase TiO₂ and ZnO appear as the predominant and minor phases, respectively, when the precursor powders are obtained at pH 5. The phases of Zn₂Ti₃O₈, anatase TiO₂, and ZnO coexist for the precursor powders obtained at pH 7. In addition, the Zn₂Ti₃O₈ and ZnO are the predominant and minor phases, respectively, for the precursor powders obtained at pH 9.     

Vector-quantization-based video codec for software-only playback on personal computers

This paper discusses a video compression and decompression method based on vector quantization (VQ) for use on general purpose computer systems without specialized hardware. After describing basic VQ coding, we survey common VQ variations and discuss their impediments in light of the target application. We discuss how the proposed video codec was designed to reduce computational complexity in every principal task of the video codec process. We propose a classified VQ scheme that satisfies the data rate, image quality, decoding speed, and encoding speed objectives for software-only video playback. The functional components of the proposed VQ method are covered in detail. The method employs a pseudo-YUV color space and criteria to detect temporal redundancy and low spatial frequency regions. A treestructured-codebook generation algorithm is proposed to reduce encoding execution time while preserving image quality. Two separate vector codebooks, each generated with the treestructured search, are employed for detail and low spatial frequency blocks. Codebook updating and sharing are proposed to further improve encoder speed and compression.     

Tape casting system for ULTCCs to fabricate multilayer and multimaterial 3D electronic packages with embedded electrodes

A 3D multilayer structure built by two ultra‐low temperature co‐fired ceramic (ULTCC) compositions with silver embedded electrodes are co‐fired at a temperature of 450°C. The 3D multilayer module is prepared by laminating the ULTCC green tapes with a new binder system, which organics can be completely burned out at temperature of 250°C before the sintering of the ULTCC 3D modulus. High‐density microstructures are achieved for the sintered module. In this study, the ULTCC feasible binder system is introduced. Also, ULTCC multilayers and multimaterial structures with surface and embedded silver electrodes are fabricated. This research opens up a new horizon for fabrication of electroceramic devices with embedded electrodes in multimaterial devices.     

Mullite formation from xerogels of (0.84–2.2) Al2O3·1SiO2

Xerogels of (0.84–2.2) Al₂O₃·1SiO₂ prepared by chemical coprecipitation of Al(NO₃)₃·9H₂O and Si(OC₂H₅)₄ experience three thermal reaction paths for mullite formation. Those with pseudoboehmite are found to form mullite via the paths of either Al-Si spinel mullite transformation or -Al₂O₃ -Al₂O₃ + amorphous SiO₂ mullite, depending upon the ratios of Al₂O₃/SiO₂. Higher SiO₂ content may prefer the former reaction. Xerogels composed of bayerite form mullite via the route -Al₂O₃ -Al₂O₃ + amorphous SiO₂ mullite. Mullite thus formed exhibits a different crystal size, being 20–25 nm for that obtained from pseudoboehmite and around 37 nm for bayerite. The highest yield of mullite formation may be achieved with xerogels of pseudoboehmite with the stoichiometric mullite compositions, 3Al₂O₃·SiO₂.     

A study on bandwidth enhancement of 900/1800 dual band LTCC chip antenna by using equivalent circuit analysis

In this article, low temperature cofired ceramic (LTCC) technology was used to realize the quarter of wavelength helical antenna instead of the quarter of wavelength monopole for achieving minimization of ceramic chip antenna (13 mm × 5.25 mm × 1.2 mm). The equivalent circuit of the helix‐monopoles combination of chip antenna has been established successfully. Using circuit simulation on the equivalent circuit model we proposed, two extra parasitic monopole antennas were added into helix antenna to enhance the second mode bandwidth because of the presence of these two close modes. The measured performance of the dual band LTCC chip antenna with helix‐three monopoles has been successfully predicted by using circuit simulation instead of EM simulation. The first and the second modes bandwidth of the dual band chip antenna can be achieved to 95 MHz (880–975 MHz) (meeting GSM band) and 300MHz (covering DCS and PCS band), respectively. The measured peak gains of this ceramic chip antenna are approximately ?1.8 dB in low band and 0.6 dB in high band based on the 120 × 40 mm² ground size. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.