نتایج جستجو برای: degradation coefficient
تعداد نتایج: 318478 فیلتر نتایج به سال:
BACKGROUND AND PURPOSE Recent improvements in MR gradient technology allow significant increases in diffusion weighting without prohibitive signal-to-noise degradation. The purpose of our investigation was to establish normative references for the signal intensity characteristics and apparent diffusion coefficient values of the adult brain at high b values. METHODS Fifty adults underwent diff...
This study presents a simple but sensitive HPLC chromatographic method with a stability-indicating assay for determination and physicochemical characterisation of L-carnosine, a promising senile cataract prophylactic agent. Chromatographic analysis was conducted using a reverse phase (RP)-HPLC system and an isocratic mobile phase of 98% v/v trifluoroacetic acid (0.1% v/v) and 2% v/v acetonitril...
Forensics for digital data has become more and more important, especially for video surveillance systems. Recently, H.264/AVC CODEC has been widely applied to video surveillance systems. In this paper, therefore, a novel video watermarking scheme for H.264/AVC CODEC is proposed. It embeds a watermark bit by adaptively truncating the last nonzero quantized AC coefficients in a 4 × 4 luminance bl...
Vapor compression systems continuously leak a small fraction of their refrigerant charge to the environment, whether during operation or servicing. As a result of the slow leak rate occurring during operation, the refrigerant charge decreases until the system is serviced and recharged. This charge degradation, after a certain limit, begins to have a detrimental effect on system capacity, energy...
Refuse degradation and landfill leachate treatment are the main research directions of landfill technology at present, but permeability characteristics of landfill body are paid little attention on. According to this actuality, the study selected four kinds of landfill's bodies under different pressures as study objects and tested the permeability characteristics in the stage of main compressio...
This paper presents new schemes to reduce the computation of Discrete Cosine Transform (DCT) with negligible peak signal-to-noise ratio (PSNR) degradation. The methods can be used in the software implementation of current video standard encoders; for example, H.26x and MPEG. We investigated the relationship between the quantization parameters and the position of the last nonzero DCT coefficient...
Dynamic tribochemical processes for dicationic ionic liquid containing a germinal 14 imidazolium cation head groups bridged by a poly(ethylene glycol) and 15 bis(trifluoromethylsulfonyl)imide anion were studied using time-resolved Mechanically 16 Stimulated Gas Emission Mass-Spectrometry (MSGE-MS). In comparison with similar 17 monocationic imidazolium ionic liquids with short alkylic or long p...
A simple stability-indicating RP-HPLC/UV method was validated for determination of beclomethasone dipropionate (BD) in nanocapsule suspensions. Chromatographic conditions consisted of a RP C18column (250 mm x 4.60 mm, 5 μm, 110 Å), using methanol and water (85:15 v/v) as mobile phase at 1.0 mL/ min with UV detection at 254 nm. The calibration curve was found to be linear in the concentration ra...
In this paper, delay and transient power-supply current (IDDT) testing has been applied for a 90nm VLIW DSP IP core, to demonstrate the IDDT testing an effective alternative of delay testing to detect aging degradation. The test environment for validation, implementing an accelerated test (AT) has been investigated, delay and IDDT measurement data resulting from AT is presented and analysed. It...
Polyoxymethylene (POM) is an engineering thermoplastic. Formaldehyde is the monomer unit of this polymer. Depolymeraization of POM occurs at 100 o C and yields formaldehyde whereas thermal degradation occurs at 270 o C. During thermal degradation, POM splits into carbon dioxide, water and formic acid. It has been proved that formaldehyde can be used as hydrogen source, when metallic nanoparticl...
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