Using Evolutionary Algorithms for Signal Integrity Assessment of High-Speed Data Buses

Today’s high performance computer systems must have fast, reliable access to memory and I/O devices. Unfortunately, inter-symbol interference, transmission line effects and other noise sources can distort data transfers. Engineers must therefore determine if bus designs have signal integrity—i.e., can transfer data with minimal amplitude or timing distortion. One method of determining signal integrity on buses is to conduct a set of data transfers and measure various signal parameters at the receiver end. But the tests must be conducted with stressful test patterns that maximize noise to help identify any potential problems. In this paper we describe how an evolutionary algorithm was used to evolve test patterns for use in intrinsic testing.     

Microwave Effects in Lead Zirconium Titanate Synthesis: Enhanced Kinetics and Changed Mechanisms

A novel, simple, and fast solid-state procedure has been demonstrated for the synthesis of Pb(Zr,Ti)O₃ (PZT), using microwave radiation. The process consists of starting with the respective oxides mixed in the required proportions and exposing the charge to the microwaves. By making one or more of the constituent oxides slightly nonstoichiometric, enormous enhancement in reaction rates has been achieved, and single-phase PZT can be synthesized at temperatures as low as 600°C. Moreover, it has been shown that the combined use of nonstoichiometric precursors and microwave irradiation leads to different reaction pathways for the formation of PZT. Further, the microwave method diminishes PbO loss.     

DSL仍旧炙手可热

在Ovum的2010年第二季度宽带接人市场份额统计表中，我们预测DSL全球市场（不包含DSL客户端设备）的8．48亿美金收入还是稍微赢过FTTB／FTTH的7．96亿美金，即使把FTTB／FTTH客户端设备——ONUs和ONTs都算进来。确实过去两年，即使FTTB／FTTH用户和相关设备增长稳健，DSL的收入每季仍缓步提高。     

A New Time-Based Iterative Solver for Linear Standing-Wave Problems

We explore time-based solvers for linear standing-wave problems, especially the oscillatory Helmholtz equation. Here, we show how to accelerate the convergence properties of timestepping. We introduce a new time-based solver that we call phase-adjusted time-averaging (PATA), which we couple to timestepping to form the PATA-TS solver. Numerical experiments indicate that the PATA-TS solver is faster than the PATA solver and timestepping by a factor of 1.2 and 1.5 or more, respectively. We also explain why the PATA-TS solver is robust, efficient, and easy to program for a variety of practical applications.     

Posttranslational modifications of cardiac and skeletal muscle proteins by reactive oxygen species after burn injury in the rat

Hepatocytes derived either from rats fed a diet enriched in n-3 fatty acids or from rats fed a low-fat diet and cultured with an n-3 fatty acid (eicosapentaenoic acid, EPA) in vitro were used to distinguish between the dietary effects and the direct effects of n-3 fatty acids on hepatocellular apolipoprotein (apo) B metabolism and secretion. ApoB-48 and apoB-100 synthesis, degradation, and secretion as large (d<1.006) and small (d>1.006) particles were determined after a pulse label with [35S]methionine. These effects were compared with changes in triacylglycerol (TAG) synthesis and secretion and with changes in de novo fatty acid synthesis (using 3H2O incorporation) under identical conditions. When n-3 fatty acid was given via the dietary route, apoB-48 very low density lipoprotein (VLDL) secretion was inhibited, but there was no effect on the secretion of apoB-100 VLDL. There was no effect on the secretion of either apoB-48 or apoB-100 as small, dense particles (d>1.006). Cellular TAG synthesis was significantly inhibited under these conditions, and fatty acid synthesis de novo was inhibited by 80%. By contrast, after direct addition of EPA to hepatocytes from normal rats, the secretion of both apoB-48 and apoB-100 VLDL was suppressed. The secretion of apoB-48, but not of apoB-100, as dense particles was also inhibited. However, there was little or no effect on TAG synthesis nor on fatty acid synthesis de novo. In addition, whereas dietary administration of n-3 fatty acid gave rise to decreased net synthesis and degradation of apoB-48, direct administration in vitro resulted in increased degradation with no effect on net synthesis. We conclude that the effects of n-3 fatty acids on hepatic lipid and apoB metabolism differ according to whether they are administered in vivo, via the dietary route, or in vitro, via direct addition to hepatocyte cultures.     

HPC5: An efficient topology generation mechanism for Gnutella networks

In this paper, we propose a completely distributed topology generation mechanism named HPC5 for Gnutella network. A Gnutella topology will be efficient and scalable if it generates less number of redundant queries. This can be achieved if it consists of a fewer number of short length cycles. Based on this principle, our protocol directs each peer to select neighbors in such a way that any cyclic path present in the overlay network will not generate any redundant query. We show that our approach can be deployed into the existing Gnutella network without disturbing any of its parameters. We also show that the probability of inconsistencies arising during topology generation, using our mechanism, which may lead to the formation of a small number of short length cycles is very low. However, we have also proposed an inconsistency handling protocol that detects such short length cycles and effectively removes them. We implemented a Gnutella prototype to compare and validate the efficiency of our protocol over existing Gnutella. Simulation results indicate that our mechanism outperforms existing Gnutella in terms of network coverage (the number of unique peers explored during query propagation in limited flooding) and message complexity. Structural analysis indicates that the proposed enhancement conserves the robustness of existing Gnutella network. Finally, we draw comparisons of the proposed protocol with a state-of-the-art topology optimization protocol named Distributed Cycle Minimization Protocol (DCMP); the simulation results indicate that HPC5 outperforms DCMP in terms of message overhead and network coverage.     

Magnetophoretic mixing for in situ immunochemical binding on magnetic beads in a microfluidic channel

Functionalized magnetic beads offer promising solutions to a host of micro-total analysis systems ranging from immunomagnetic biosensors to cell separators. Immunochemical binding of functional biochemical agents or target biomolecules serves as a key step in such applications. Here we show how magnetophoretic motion of magnetic microspheres in a microchannel is harnessed to promote in situ immunochemical binding of short DNA strands (probe oligonucleotide) on the bead surface via streptavidin–biotin bonds. Using a transverse magnetic field gradient, the particles are transported across a co-flowing analyte stream containing biotinylated probe oligonucleotides that are labeled with a Cy3-fluorophore. Quantification of the resulting biotin–streptavidin promoted binding has been achieved through fluorescence imaging of the magnetophoretically separated magnetic particles in a third stream of phosphate buffered saline. Both the experimental and numerical data indicate that for a given flow rate, the analyte binding per bead depends on the flow fraction of the co-flowing analyte stream through the microchannel, but not on the fluid viscosity. Parametric studies of the effects of fluid viscosity, analyte flow fraction, and total flow rate on the extent of binding and the overall analyte separation rate are also conducted numerically to identify favorable operating regimes of a flow-through immunomagnetic separator for biosensing, cell separation, or high-throughput applications.     

Fabrication of polymer micro-tip by optical lensing technique

Fabrication of polymer micro-tips using SU-8 negative photoresist for bio-applications is reported. The SU-8 processing technology and isotropic glass etching process have been developed and utilized to fabricate micro-tips on glass substrate by applying optical lensing effect during photolithography. Experimentally, micro-tips of 25?μm base diameter, ~1?μm tip diameter, and ~250?μm height, have been demonstrated.     

A modified correlation to predict the minimum velocity required to elutriate solids from a liquid-fluidized bed

The consideration of sphericity of solids for the prediction of u_me gives rise to some improvement of the correlation proposed earlier by the author. In the absence of wall-effect, the following correlation is obtained: which gives a standard deviation of ± 16.3% for 138 different experiments as against ± 21.6% for 134 runs by the correlation reported earlier. The ranges of the various groups are