Browsing Mathematics, Statistics & Physics by Publication Date
Now showing items 21-40 of 767
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Mechanical and thermal properties of gamma-ray irradiated polyethylene blends
( Elsevier , 2003 , Conference)In this work, the results obtained by gamma-ray irradiation of polyethylene (PE) blends are presented. The blends were produced by injection molding at 220°C with different compositional ratios, i.e. 100/0, 15/85, 25/75, ... -
Ion beam modification of surface properties of polyethylene
( Elsevier , 2003 , Conference)Improvement of polymer tribological properties is an essential issue for their application when used as parts of machines or artificial human joints. Ion implantation is a very promising technique in this respect. This ... -
The Structure of the Free Volume in Poly(styrene-co-acrylonitrile) from Positron Lifetime and Pressure Volume Temperature (PVT) Experiments
( WILEY-VCH Verlag , 2004 , Article)Summary: The structure of the free volume and its temperature dependence between 25 and 190 °C of copolymers of styrene with acrylonitrile, SAN (0 to 50 mol-% AN), is studied by pressure volume temperature (PVT) experiments ... -
Positron annihilation lifetime study of helium ions implanted polyethylene blends
( Trans Tech Publications Ltd , 2004 , Conference)The structural defects of linear low density polyethylene (LLDPE) and high density polyethylene (HOPE) blends implanted with helium ions were investigated using position annihilation lifetime (PAL) technique. The positron ... -
Surface layer modification of ion bombarded HDPE
( Elsevier , 2004 , Article)Press-moulded, high density polyethylene (HDPE) samples were subjected to ion bombardment and effects of the modification studied. He+ ions of energy 100 keV or Ar+ ions of energy 130 keV were applied in the range of dose ... -
Is hypertension a predictor for heart failure? A cross cultural comparison over a 10-year period
( Elsevier B.V. , 2005 , Article)This was a retrospective cohort study to assess the effect of hypertension (HTN) among Qatari and Asian patients admitted to the Hamad General Hospital in Qatar with heart failure (HF) and to identify risk factors that ... -
On the preparation of electron sensor using LiRbSO4 samples
( WILEY-VCH Verlag GmbH & Co. , 2005 , Article)The dielectric spectroscopy of metal�metal sulfate LiRbSO4 samples are described with particular emphasis on sensor performance to be used in the field of radiation. The obtained results as the effect of different electron ... -
Compositional transformations in ion implanted polymers
( Elsevier , 2005 , Conference)Changes of surface layer composition produced by ion bombardment of polyethylene and polypropylene samples were studied. These materials are under consideration for load bearing surfaces in biological and technical ... -
Disability, depression and somatization in a low back pain population
( Blackwell Publishing Asia , 2006 , Article)Objective: The aim of this study was to determine the prevalence of low back pain (LBP) in a primary care setting population and examine its association with the symptoms of depression and somatization. Methods: This ... -
Large sample and bootstrap intervals for the gamma scale parameter based on grouped data
( Wayne State University , 2006 , Article)Interval estimation of the scale parameter of the gamma distribution using grouped data is considered in this article. Exact intervals do not exist and approximate intervals are needed Recently, Chen and Mi (2001) proposed ... -
Self-implantation of Cz-Si: Clustering and annealing of defects
( Elsevier , 2006 , Article)Observations of vacancy clusters formed in Czochralski (Cz) Si after high energy ion implantation are reported. Vacancy clusters were created by 2 MeV Si ion implantation of 1 × 10 15 ions/cm 2 and after annealing between ... -
Applied surface Science: Preface
( Elsevier , 2006 , Other)not available -
The effect of gamma irradiation and shelf aging in air on the oxidation of ultra-high molecular weight polyethylene
( Elsevier , 2006 , Article)This study has investigated the effect of shelf aging, for up to one year in air, on the properties of gamma-irradiated ultra-high molecular weight polyethylene (UHMWPE). A variety of techniques were used to characterize ... -
Investigations of He <sup>+</sup> implantation and subsequent annealing effects in InP
( Elsevier , 2006 , Article)The influence of 70 keV He + ion implantation and subsequent annealing of Cz-indium phosphide (InP) samples has been investigated using a slow positron beam-based Doppler broadening spectrometer. Three samples with ion ... -
The effects of ion bombardment of ultra-high molecular weight polyethylene
( Elsevier , 2006 , Article)Ion bombardment is a suitable tool to improve tribological properties of polymers. In this study UHMWPE samples were bombarded with 130keV He ions to the fluences ranging from 1×1014 to 2×1016cm−2. RBS and NRA techniques ... -
Corrosion properties of duplex treated Ti-6Al-4V alloy in chloride media using electrochemical and positron annihilation spectroscopy techniques
( Elsevier B.V. , 2006 , Article)The corrosion properties of duplex-treated and nitrided Ti-6Al-4V have been investigated in 0.025, 0.25 and 2.5 M NaCl using electrochemical techniques, Positron Annihilation Spectroscopy (PAS), X-ray diffraction (XRD), ... -
Weighted estimates for rough parametric Marcinkiewicz integrals
( Korean Mathematical Society , 2007 , Article)We establish a weighted norm inequality for a class of rough parametric Marcinkiewicz integral operators . As an application of this inequality, we obtain weighted inequalities for a class of parametric Marcinkiewicz ... -
An upper bound of the basis number of the semi-strong product of cycles with bipartite graphs
( The Korean Mathematical Society , 2007 , Article)An upper bound of the basis number of the semi-strong product of cycles with bipartite graphs is given. Also, an example is presented where the bound is achieved. -
A rich learning lesson using the Poisson distribution
( Elsevier B.V. , 2007 , Article)In this note, we explore the rich information about inference that the Poisson distribution has. The source of this information is mainly the fact that the mean and variance of this distribution are equal. -
Gamma irradiation effects on polymethyl methacrylate
( WILEY-VCH Verlag , 2007 , Article)The effect of gamma-irradiation on the structure of polymethyl methacrylate (PMMA) has been investigated. In this study, the PMMA specimens were gamma-irradiated at doses in the range of 0-1000 kGy and measured by means ...
