Image analysis by pseudo-Jacobi (p = 4, q = 3)-Fourier moments

Pseudo-Jacobi (p = 4, q = 3)-Fourier moments (PJFMs) based on Jacobi polynomials are described. The new orthogonal radial polynomials have almost uniformly distributed (n + 2) zeros in the region of small radial distance 0 < or = r < or = 1. Both theoretical and experimental results indicate that PJFMs are better than orthogonal Fourier-Mellin moments in terms of reconstruction errors and signal-to-noise ratio. The PJFMs are normalized to shift, rotation, scale, and intensity invariance, and some pattern-recognition experiments are described.     

Springtime depletion of mercury in the European Arctic as observed at Svalbard

This study was carried out to see whether the geographical extent of the mercury depletion events (MDEs), first seen at Alert in the Canadian High Arctic, is also covering Svalbard. Another goal was to determine the main reaction products from the MDE and their fate. Gaseous elemental mercury (GEM), total particulate mercury (TPM), reactive gaseous mercury (RGM) and total mercury in surface snow have been measured at the Zeppelin mountain during 2000. GEM has been measured with a high time resolution automatic monitor (Tekran 2537A) based on CV-AFS, TPM was sampled/measured using high volume samplers/CV-AFS and RGM was sampled with annular denuders and measured by CV-AFS (Gardis Hg-monitor). During spring of 2000, in the three-month period following polar sunrise, there were several episodic depletions in GEM concentration correlating well with the depletion of surface ozone. Measurements of RGM and TPM showed higher concentrations of these mercury species during the depletion period than during the rest of the year. Total mercury in surface snow showed a distinct increase from the polar night to the Arctic spring. MDEs are caused by the specific chemical and physical conditions observed in the Arctic during spring. GEM is oxidised and converted to more reactive forms (RGM and/or TPM), which have considerably higher deposition velocities than elemental mercury, leading to an overall enhanced deposition flux of mercury.     

New Amino‐Acid‐Based β‐Phosphorylated Nitroxides for Probing Acidic pH in Biological Systems by EPR Spectroscopy

There is increasing interest in measuring pH in biological samples by using nitroxides with pH‐dependent electron paramagnetic resonance (EPR) spectra. Aiming to improve the spectral sensitivity (Δa_X) of these probes (i.e., the difference between the EPR hyperfine splitting (hfs) in their protonated and unprotonated forms), we characterized a series of novel linear α‐carboxy, α′‐diethoxyphosphoryl nitroxides constructed on an amino acid core and featuring an (α or α′)‐C?H bond. In buffer, the three main hfs (a_N, a_H, and a_P) of their EPR spectra vary reversibly with pH and, from a_P or a_H titration curves, a two‐ to fourfold increase in sensitivity was achieved compared to reference imidazoline or imidazolidine nitroxides. The crystallized carboxylate 10 b (pK_a ≈3.6), which demonstrated low cytotoxicity and good resistance to bioreduction, was applied to probe stomach acidity in rats. The results pave the way to a novel generation of highly sensitive EPR pH markers.     

平板电脑研究综述

从操作系统、硬件、应用等方面对平板电脑的市场进行了分析,并作出了相应的总结和预测。     

PWM zero-voltage switching boost-derived converters with outputisolation

In this paper, the basic operations and steady-state analysis for three modified boost-derived power converter topologies are presented. Unlike the conventional boost topology, these power converters provide electrical isolation and zero-voltage switching, while having identical component stresses as those in the conventional boost power converters. Zero-voltage switching and proper transformer-core resetting are achieved from the resonance that occurs between the parasitic capacitance of the power switch and the transformer magnetizing inductance. By introducing a lossless clamping circuit, the voltage stresses across the switching devices are limited to the reflected output voltage to the primary side     

Micelle mediated extraction and simultaneous spectrophotometric determination of vanadium(V) and molybdenum(VI) in plant foodstuff samples

A micelle-mediated extraction method for preconcentration of trace quantities of V(V) and Mo(VI) as a prior step to their simultaneous spectrophotometric determination has been developed. Bromopyrogallol red, cetyltrimethylammonium bromide (CTAB) (cationic surfactant) and KI were used as chelating, extraction and co-extraction agents, respectively.     

Magnetic and Cytotoxicity Properties of La1−x Sr x MnO3 (0 ≤ x ≤ 0.5) Nanoparticles Prepared by a Simple Thermal Hydro-Decomposition

This study reports the magnetic and cytotoxicity properties of magnetic nanoparticles of La_1−x Sr _x MnO₃ (LSMO) with x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5 by a simple thermal decomposition method by using acetate salts of La, Sr, and Mn as starting materials in aqueous solution. To obtain the LSMO nanoparticles, thermal decomposition of the precursor was carried out at the temperatures of 600, 700, 800, and 900 °C for 6 h. The synthesized LSMO nanoparticles were characterized by XRD, FT-IR, TEM, and SEM. Structural characterization shows that the prepared particles consist of two phases of LaMnO₃ (LMO) and LSMO with crystallite sizes ranging from 20 nm to 87 nm. All the prepared samples have a perovskite structure with transformation from cubic to rhombohedral at thermal decomposition temperature higher than 900 °C in LSMO samples of x ≤ 0.3. Basic magnetic characteristics such as saturated magnetization (M _S) and coercive field (H _C) were evaluated by vibrating sample magnetometry at room temperature (20 °C). The samples show paramagnetic behavior for all the samples with x = 0 or LMO, and a superparamagnetic behavior for the other samples having M _S values of ~20–47 emu/g and the H _C values of ~10–40 Oe, depending on the crystallite size and thermal decomposition temperature. Cytotoxicity of the synthesized LSMO nanoparticles was also evaluated with NIH 3T3 cells and the result shows that the synthesized nanoparticles were not toxic to the cells as determined from cell viability in response to the liquid extract of LSMO nanoparticles.     

On the stability of adaptive Service Level Agreements

We consider some implications of non-linear feedback, due to policy combinatorics, on policy-based management of networked services. We pay special attention to the case where the monitoring of certain aspects of Service Level Agreements is used to alter future policy dynamically, according to a control feedback scheme. Using two simple models, we show that nonlinear policies are generally unstable to service provision, i.e. provide no reliable service levels (QoS). Hence we conclude that automated control by policy-rule combinatorics can damage quality of service goals.     

Drying equations of Thai Hom Mali paddy by using hot air,carbon dioxide and nitrogen gases as drying media

The objective of this study was to develop a drying equation for predicting the thin layer drying kinetics of dried Thai Hom Mali paddy using different drying gases. Thai Hom Mali paddy cv. Khao Dok Mali 105 with initial moisture content of 32% dry basis was dried in a heat pump dryer at 0.4 m/s fixed superficial velocity, 60% fixed evaporator bypass air ratio, and varied drying temperatures of 40, 50, 60 and 70 °C using hot air, CO₂ and N₂ gases as drying media. Drying rate was not affected by drying gases but increased with drying temperatures. Moisture ratios, at any given time during the drying process, were compared among various models, namely, Newton, Page, Modified Page I, Henderson and Pabis, two-term, approximation of diffusion, and Midilli. The effect of drying air temperatures on the coefficients of the best moisture ratio model was determined by single step regression method. The R² coefficient, root mean square error (RMSE) and chi-square (χ²) were criteria for selecting the best model. The study found that the Midilli model was the best model for describing the drying behavior of Thai Hom Mali paddy in every evaluated drying gas. It should be possible to predict the moisture content of a product with a generalized model that shows the effect of drying air temperature on the model constants and coefficients.     

Resource-sharing among autonomous agents

We study a scenario for cloud services based on autonomous resource management agents in situations of competition for limited resources. In the scenario, autonomous agents make independent decisions on resource consumption in a competitive environment. Altruistic and selfish strategies for agent behaviour are simulated and compared with respect to whether they lead to successful resource management in the overall system, and how much information exchange is needed among the agents for the strategies to work. Our results imply that local agent information could be sufficient for global optimisation. Also, the selfish strategy proved stable compared to uninformed altruistic behaviour.