Efficient Realization of Large Size Two’s Complement Multipliers Using Embedded Blocks in FPGAs

This paper presents an optimized design approach for two’s complement large size multipliers using smaller size embedded multiplier blocks available as resources in field programmable gate arrays (FPGAs). The realization is based on the Baugh–Wooley algorithm, which segments the multiplication into unsigned and signed components. To achieve efficient implementation results, a set of optimized schemes for the realization of the additions required for the unsigned multipliers and for combining the unsigned and signed components is proposed. The implementations of the multipliers have been carried out for operands with sizes ranging from 20 to 128 bits. The designs are synthesized and implemented on Xilinx’s Spartan-3 in the ISE 8.1 design platform and compared with three other realizations using the following approaches: (1) conventional sign-extension approach, (2) Xilinx’s IP-Core generator, and (3) sign-and-magnitude-based approach. The experimental results indicate that our proposed method outperforms the other techniques.     

Adsorption property and affinity chromatography of polystyrene derivative sorbent towards cow's milk xanthine oxidase

On the basis of the biospecific molecular recognition between complementary chemical groups of xanthine oxidase (XO) and their ligands particularly sulphated glycoaminoglycans and heparin. Poly (styrene chlorosulfonyl) particles modified by sulfonate sodium groups was synthesized and its adsorption property towards cow's milk XO was established. The adsorption of XO onto this functional polymer was performed in batch at 4 °C and at pH 6.0 during 30 min. of incubation. The adsorbed XO content at the interface allows establishing the chemisorption isotherm curve. The affinity association estimated from this adsorption isotherm according to the Langmuir equation was found to be significantly high in the magnitude of 1.25 × 10⁶ M^? 1. Affinity chromatography on column using this functional polymer as a stationary phase confirms its high ability to adsorb XO at low ionic strength. In fact, the xanthine oxidase of the crude extract is strongly adsorbed onto the sorbent and is eluted at high ionic strength with out any significant loss of its biological activity. The purified enzyme possesses a protein flavin ratio (PFR) of 6.05 with a specific activity of 1.78 UI/mg. On the other hand, the electrophoresis of XO fraction showed a single band with a molecular weight of about 150 kDa. Thus, the synthesized beads functionalized by sulfonate group could be used efficiently and advantageously in the purification of XO instead of other conventional chromatographic methods which need several steps.     

Characterization of the absorption of theophylline from immediate- and controlled-release dosage forms with a numerical approach using the in vitro dissolution-permeation process using caco-2 cells

After oral administration, drug absorption rate is recognized to be dependent on two major factors: dissolution and intestinal cells permeability. Caco-2 monolayer cells have been largely used as a permeation study model. In this study, a numerical approach funded on an exponential first-order time relationship was tested to compare immediate- and controlled-release tablets of theophylline using a dissolution-permeation system. The dissolution performance using USP II paddle apparatus was coupled to the permeability studies investigated in Caco-2 cell monolayers. The dissolved samples were taken at different times; their pH and osmolarity were adjusted to render them suitable to Caco-2 permeability studies (osmolarity = 300 mosm, pH = 7.4). The experimental data show that the dissolution fits the exponential first-order relationship rate. The permeability values were in a range of 4.45 10(- 6)-5.28 10(- 6) cm/s, and percentages of absorbed drug dose were dependent on the fraction initially present in the donor compartment, indicating that absorption of theophylline was dissolution rate limited. Plotting experimental absorbed fractions (F(a)) against experimental dissolved fractions (F(d)) show that permeation is the rate-limiting step in drug absorption process in the extended release form of theophylline. Our results demonstrate a general agreement between observed F(a)/F(d) relationships and theoretical F(a)/F(d) relationships obtained with our approach funded on dissolution and permeation behavior. We concluded that the couple dissolution-caco-2 system could be a useful tool to characterize intestinal permeation for a new formulation of a drug compared with the conventional one.     

Adaptive modulation and combining for bandwidth and power efficient communication over fading channels

Traditional fading mitigation techniques are designed relative to the worst‐case channel conditions, resulting in a poor utilization of the spectrum and the available power a good percentage of the time. In contrast, we introduce and investigate in this paper new adaptive modulation and diversity combining techniques that jointly select the most appropriate constellation size and the most suitable diversity branches in response to the channel variation and given a desired bit error rate (BER) requirement. Numerical results show that these newly proposed adaptive modulation and combining schemes can reduce considerably the average receiver channel estimation complexity as well as the power drain from the battery while offering high spectral efficiency and satisfying the desired outage probability and BER requirements. Copyright © 2006 John Wiley & Sons, Ltd.     

Mechanical Properties Analysis of 4340 Steel Specimen Heat Treated in Oven and Quenching in Three Different Fluids

This paper proposes a statistical approach to analyze the mechanical properties of a standard test specimen, of cylindrical geometry and in steel 4340, with a diameter of 6 mm, heat-treated and quenched in three different fluids. Samples were evaluated in standard tensile test to access their characteristic quantities: hardness, modulus of elasticity, yield strength, tensile strength and ultimate deformation. The proposed approach is gradually being built (a) by a presentation of the experimental device, (b) a presentation of the experimental plan and the results of the mechanical tests, (c) anova analysis of variance and a representation of the output responses using the RSM response surface method, and (d) an analysis of the results and discussion. The feasibility and effectiveness of the proposed approach leads to a precise and reliable model capable of predicting the variation of mechanical properties, depending on the tempering temperature, the tempering time and the cooling capacity of the quenching medium.     

Mechanical investigation of tunnels: risk analysis and notation system

The current mechanical investigation strategy applied to RATP (Régie Autonome des Transpots Parisiens) tunnels is mainly based on visual inspection. All the works are inspected and every apparent fault is located and reported in inspection reports. However, this type of inspection detects only apparent faults without linking them to their causes. A new methodology of mechanical investigation is proposed in the framework of the ANR project MEDITOSS (Méthodologie de Diagnostic des Tunnels et Ouvrages Souterrains en Service), consisting in integrating mechanical investigation tools to better characterise the geometrical and mechanical state of the tunnel. This new strategy combines four techniques (ground penetrating radar, light dynamic penetrometer, endoscopy and geo-mechanical impedance). These techniques are applied to panels to obtain a ‘panel score’. This paper presents a risk analysis of the system studied (network of corridors and tunnels), by applying the bow-tie method in order to obtain information on its elements, its function and its pathologies. This analysis incorporates a quantitative characterisation method (scoring) to assess the state of corridors and tunnels. These methods are tested on infiltration and cracking pathologies for the risk analysis and on the notation of a corridor for the quantitative quantification.     

LED发光式LAN电缆测试器

电缆与连接器故障在LAN(局域网)中相对较常见。图1的电路可以测试直通或交叉式10BaseT、100BaseT或千兆位UTP(非屏蔽双绞线)和STP(屏蔽双绞线)电缆。电路会对每个链接线对作一次连续测试。当电缆两端RJ-45连接器的相应线对正确连