479 research outputs found

    Trap levels in layered semiconductor Ga2SeS

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    Cataloged from PDF version of article.Trap levels in nominally undoped Ga2SeS layered crystals have been characterized by thermally stimulated current (TSC) measurements. During the measurements, current was allowed to flow along the c-axis of the crystals in the temperature range of 10-300 K. Two distinct TSC peaks were observed in the spectra, deconvolution of which yielded three peaks. The results are analyzed by curve fitting, peak shape and initial rise methods. They all seem to be in good agreement with each other. The activation energies of three trapping centers in Ga2SeS are found to be 72, 100 and 150 meV. The capture cross section of these traps are 6.7 x 10(-23), 1.8 x 10(-23) and 2.8 x 10(-22) cm(2) with concentrations of 1.3 x 10(12), 5.4 x 10(12) and 4.2 x 10(12) cm(-3), respectively. (C) 2004 Elsevier Ltd. All rights reserved

    Thermally stimulated currents in layered Ga4SeS3 semiconductor

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    Cataloged from PDF version of article.Thermally stimulated current (TSC) measurements are carried out on nominally undoped Ga4SeS3 layered semiconductor samples with the cur-rent flowing along the c-axis in the temperature range of 10 to 150 K. The results are analyzed according to various methods, such as curve fitting, initial rise and Chen's methods, which seem to be in good agreement with each other. Experimental evidence is found for the presence of three trapping centers in Ga4SeS3 with activation energies of 70, 210 and 357 meV. The calculation yielded 7.9 x 10(-21), 7.0 x 10(-19) and 1.5 x 10(-13) cm(2) for the capture cross section, and 1.6 x 10(10), 6.5 x 10(10) and 1.2 x 10(11) cm(-3) for the concentration of the traps studied. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

    An Alternative Approach to the Fracture Toughness of Dual Phase Steels

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    In this study, the effects of ferrite morphology and of ferrite volume fraction on the mechanical properties and the fracture toughness values ( ) KIc of dual phase steels were investigated. The fracture toughness values were determined using an approach that was different from the standard one. A homogenization heat treatment was applied to the steels. Two different starting microstructures were then obtained by either the full annealing of or the quenching of the steels from austenite before applying intercritical annealing to the steels in the austenite region. After this process, dual phase steels with two types of morphology, coarse and fine, were obtained with 40, 20, and 10% ferrite volume fractions, depending on the starting microstructure. Tempered specimens with 10% ferrite exhibited improved fracture toughness values compared with those of the other steels.Исследуется влияние морфологии структуры феррита и его объемного содержания на механические свойства и вязкость разрушения двухфазных сталей. Для определения значений вязкости разрушения использовали не стандартный, а альтернативный подход. Стали подвергали гомогенизирующей термообработке. Путем полного отжига или закалки сталей из аустенитного состояния до применения докритического отжига в аустенитной области получены две различные исходные микроструктуры. Получены двухфазные стали с двумя типами морфологии (крупно- и мелкозернистая) с 40-, 20- и 10%-ным объемным содержанием феррита в зависимости от исходной микроструктуры. Отпущенные образцы с 10%-ным объемным содержанием феррита имели более высокие значения вязкости разрушения по сравнению с таковыми других образцов из этих сталейДосліджується вплив морфології структури фериту та його об’ємного вмісту на механічні властивості і в’язкість руйнування двофазних сталей. Для визначення значень в’язкості руйнування використовували не стандартний, а альтернативний підхід. Сталі піддавали гомогенізуючій термообробці. Шляхом повного відпалу або загартування сталей з аустенітного стану до використання докритичного відпалу в аустенітній області отримано дві різні початкові мікроструктури. Отримано двофазні сталі з двома типами морфології (великоі дрібнозеренна) з 40-, 20- і 10%-ним об’ємним вмістом фериту в залежності від початкової мікроструктури. Відпущені зразки з 10%-ним об’ємним вмістом фериту мали більш високі значення в’язкості руйнування порівняно з такими інших зразків із цих сталей

    Does progesterone therapy increase nuchal translucency in women with threatened miscarriage?

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    Objectives: The effect of exogenous progesterone on fetal nuchal translucency (NT) has been proposed recently. In this study, we aimed to compare the thickness of NT of patients receiving and not receiving progesterone for threatened miscarriage. Material and methods: This study was designed as a retrospective comparative study. Ninety five women treated with progesterone constituted the study group whereas 97 women who were not treated with progesterone constituted the control group. An ultrasonographic examination was performed on all of the women to measure NT. All patients were treated with oral micronized progesterone in the study group. The main parameters recorded for each woman were; age, body mass index (BMI), obstetrical characteristics, and gestational age at first examination, treatment duration of progesterone therapy, and results of combined and triple tests. Results: A total of 192 pregnant women with threatened miscarriage were included in this study. The mean NT thickness was statistically significantly higher in the study group (p < 0.001), and mean serum level of human chorionic gonadotropin (hCG) was also higher in this group (p < 0.05). There was no statistically significant difference between groups in terms of age, BMI, and gestational age at first examination. ROC curve analysis demonstrated that only increased NT (area under the curve: 0.634, p = 0.005, 95% CI: 0.541–0.727) was a discriminative factor for women receiving progesterone for threatened miscarriage. Also there was a positive correlation between NT and treatment duration (r = 0.269; p < 0.001). Conclusions: We think that oral progesterone therapy may increase NT depending on treatment duration without causing abnormal prenatal screening test results

    Učinci liječenja fenetil esterom kavene kiseline na reumatološke pokazatelje i metabolizam željeza u štakorica s izazvanom šećernom bolešću.

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    Diabetology and rheumatology have much in common, including many biochemical features. Diabetic cases suffer excessively from common musculoskeletal conditions. The present study aimed to explore the association between the caffeic acid phenethyl ester (CAPE) treatment and the standard parameters of diabetic and rheumatologic controls. Serum anti-streptolysin-O (ASO), C-reactive protein (CRP), rheumatoid factor (RF) titers and glucose (GLU), cholesterol (CHOL), triglyceride (TG), high density lipoprotein (HDL), very low density lipoprotein (VLDL), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), sodium (Na), potassium (K), chloride (Cl), calcium (Ca), phosphorus (P), uric acid (UA), iron (Fe), iron-binding capacity (IBC), total iron-binding capacity (TIBC) and superoxide dismutase (SOD) levels were measured in 22 female Wistar-Albino rats. The animals were divided into three groups: group 1: non-diabetic rats as control; group 2: streptozotocin (STZ)-induced, untreated diabetic rats; and group 3: STZ-induced, CAPE-treated diabetic rats. Levels of GLU were increased in group 2. ASO values were decreased in group 3. TG and VLDL levels were increased in group 3 compared with the group 1. Higher UA levels were detected in group 3 compared with group 2. The levels of Fe and TIBC were decreased in group 3. The results of the present study indicate the reducing effect of CAPE on the serum levels of diabetic and rheumatologic parameters in diabetic rats.Dijabetologija i reumatologija imaju mnoge sličnosti, uključujući biokemijske procese. Oboljeli od dijabetesa pate od teških stanja mišićno-koštanog sustava. U ovom radu istražena je povezanost između liječenja fenetil esterom kavene kiseline i standardnih pokazatelja koji se kontroliraju pri dijabetičnim i reumatoidnim bolestima. Kod 22 Wistar-Albino štakorice mjereni su: serumski anti-streptolizin-O (ASO), C-reaktivni protein (CRP), titar reumatoidnog faktora (RF), zatim razina glukoze (GLU), kolesterola (CHOL), triglicerida (TG), lipoproteina visoke gustoće (HDL), lipoproteina vrlo niske gustoće (VLDL), alkalne fosfataze (ALP), gamaglutamil transferaze (GGT), natrija (Na), kalija (K), klorida (Cl), kalcija (Ca), fosfora (P), mokraćne kiseline (UA), željeza (Fe), kapaciteta vezanja željeza (IBC), ukupnog kapaciteta vezanja željeza (TIBC) i superoksid dismutaze (SOD). Životinje su bile podijeljene u tri skupine: 1. štakorice bez dijabetesa (kontrolna skupina), 2. neliječene štakorice s dijabetesom izazvanim streptozotocinom (STZ) i 3. štakorice sa streptozotocin (STZ) - izazvanim dijabetesom liječenim fenetil esterom kavene kiseline. Razine GLU bile su povećane u skupini 2. ASO vrijednosti bile su snižene u skupini 3. Razine TG i VLDL bile su povišene u skupini 3 u usporedbi s razinama u skupini 1. Više razine UA utvrđene su u skupini 3 u usporedbi sa skupinom 2. Razine Fe i TIBC bile su snižene u skupini 3. Rezultati pokazuju reducirajuće učinke fenetil estera kavene kiseline na razinu dijabetičnih i reumatoloških pokazatelja u serumu štakorica sa šećernom bolešću izazvanom streptozotocinom

    Trap levels in layered semiconductor Ga 2 SeS

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    Abstract Trap levels in nominally undoped Ga 2 SeS layered crystals have been characterized by thermally stimulated current (TSC) measurements. During the measurements, current was allowed to flow along the c-axis of the crystals in the temperature range of 10-300 K. Two distinct TSC peaks were observed in the spectra, deconvolution of which yielded three peaks. The results are analyzed by curve fitting, peak shape and initial rise methods. They all seem to be in good agreement with each other. The activation energies of three trapping centers in Ga 2 SeS are found to be 72, 100 and 150 meV. The capture cross section of these traps are 6.7!10 K23 , 1

    The effect of supersymmetric CP phases on Chargino-Pair Production via Drell-Yan Process at the LHC

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    We compute the rates for pp annihilation into chargino-pairs via Drell-Yan process taking into account the effects of supersymmetric soft phases, at proton-proton collider. In particular, the phase of the mu parameter gains direct accessibility via the production of dissimilar charginos. The phases of the trilinear soft masses do not have a significant effect on the cross sections.Comment: 24 pages, 7 figure

    Morphometric analysis of fossil bumble bees (Hymenoptera, Apidae, Bombini) reveals their taxonomic affinities

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    This work is licensed under a Creative Commons Attribution 4.0 International License.Bumble bees (Bombus spp.) are a widespread corbiculate lineage (Apinae: Corbiculata: Bombini), mostly found among temperate and alpine ecosystems. Approximately 260 species have been recognized and grouped recently into a simplified system of 15 subgenera. Most of the species are nest-building and primitively eusocial. Species of Bombus have been more intensely studied than any other lineages of bees with the exception of the honey bees. However, most bumble bee fossils are poorly described and documented, making their placement relative to other Bombus uncertain. A large portion of the known and presumed bumble bee fossils were re-examined in an attempt to better understand their affinities with extant Bombini. The taxonomic affinities of fossil specimens were re-assessed based on morphological features and previous descriptions, and for 13 specimens based on geometric morphometrics of forewing shape. None of the specimens coming from Eocene and Oligocene deposits were assigned within the contemporary shape space of any subgenus of Bombus. It is shown that Calyptapis florissantensis Cockerell, 1906 (Eocene-Oligocene boundary, Florissant shale, Colorado, USA) and Oligobombus cuspidatus Antropov, 2014 (Late Eocene, Bembridge Marls) likely belong to stem-group Bombini. Bombus anacolus Zhang, 1994, B. dilectus Zhang, 1994, B. luianus Zhang, 1990 (Middle Miocene, Shanwang Formation), as well as B. vetustus Rasnitsyn & Michener, 1991 (Miocene, Botchi Formation) are considered as species inquirenda. In the Miocene, affinities of fossils with derived subgenera of Bombus s. l. increased, and some are included in the shape space of contemporary subgenera: Cullumanobombus (i.e., B. pristinus Unger, 1867, B. randeckensis Wappler & Engel, 2012, and B. trophonius Prokop, Dehon, Michez & Engel, 2017), Melanobombus (i.e., B. cerdanyensis Dehon, De Meulemeester & Engel, 2014), and Mendacibombus (i.e., B. beskonakensis (Nel & Petrulevičius, 2003), new combination), agreeing with previous estimates of diversification
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