288 research outputs found

    Preferential etching by flowing oxygen on the (100) surfaces of HPHT single-crystal diamond

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    Application of diamond is determined by its oxidation behaviour in some measure. Oxidation process of single-crystal diamond prepared under high pressure and high temperature has been studied by the thermal analysis, scanning electron microscope and Raman spectrometer. The result of a simultaneous thermal analysis indicates that single-crystal diamond is oxidized at ~ 818 °C at a heating rate of 5°C/min in the flowing oxygen. Based on the data of the thermal analysis at different heating rates, the activation energy is calculated by the Kissinger method. A weight loss rate increases with the rising heat treatment temperature from 600 to 800°C. After the oxidation at 800 °C, etch pits emerge on the {100} surfaces of single-crystal diamond, while the {111} surfaces are smooth. Shapes of the etch pits on the {100} surfaces are inverted pyramidal hollows, with edges direction parallel to the direction.Застосування алмазу в якійсь мірі визначається його поведінкою при окисленні. За допомогою термічного аналізу, скануючої електронної мікроскопії і спектроскопії комбінаційного розсіювання світла вивчено процес окислення монокристалічного алмазу, отриманого при високому тиску і високій температурі. Одночасний термічний аналіз показав, що монокристалічний алмаз окислюється при ~ 818 °С при швидкості нагріву 5 °С/хв в потоці кисню. На основі даних термічного аналізу при різних швидкостях нагрівання розраховано енергію активації за методом Кіссінджера. Швидкість втрати ваги зростає з підвищенням температури термообробки від 600 до 800 °C. Після окислення при температурі 800 °С ямки травлення з’являються на поверхні {100} монокристалічного алмазу, в той час як поверхні {111} гладкі. Форма ямок на поверхнях {100} – перевернуті пірамідальні западини з ребрами в напрямку паралельному .Применение алмаза в какой-то мере определяется его поведением при окислении. С помощью термического анализа, сканирующей электронной микроскопии и спектроскопии комбинационного рассеяния света изучен процесс окисления монокристаллического алмаза, полученного при высоком давлении и высокой температуре. Одновременный термический анализ показывает, что монокристаллический алмаз окисляется при ~ 818 °С при скорости нагрева 5 °С/мин в потоке кислорода. На основе данных термического анализа при различных скоростях нагрева рассчитана энергия активации по методу Киссинджера. Скорость потери веса возрастает с повышением температуры термообработки от 600 до 800 °C. После окисления при температуре 800 °С ямки травления появляются на поверхности {100} монокристаллического алмаза, в то время как поверхности {111} гладкие. Форма ямок на поверхностях {100} – перевернутые пирамидальные впадины с ребрами в направлении параллельном

    Experimental Study on Seismic Behavior of Cluster-Reinforced Precast Concrete Columns with Grouting-Anchor Connections

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    The prefabricated residential buildings have become one of the most dominating construction methods in the modern construction industry. The seismic behavior of prefabricated components is crucial in the limit state design of the precast structure. This paper investigates the seismic behavior of a new type precast concrete column that has clustered steel reinforcement with grouting connection. Quasi-static tests are carried out on three cast-in-situ columns and seven precast columns. Axial compression ratio, lap length and lap space are the main variables considered. The failure process, hysteresis curve, skeleton curve, stiffness degradation, displacement ductility and energy dissipation are elaborated. The experimental results show that the precast columns with cluster reinforcement have similar seismic behavior to the cast-in-situ columns. Reducing the axial pressure can improve the ductility and energy consumption performance of the cluster-reinforced columns and exert its ductility to improve its seismic performance. During the assembly, a moderate increase in lap length can improve the seismic behavior of precast columns, whereas the lap space has an insignificant effect on the seismic behavior which indicates that the lap space is not an important factor during construction. The research outcome can serve as a reference for further development and application of precast structures

    Time-Dependent CP Violation Effects in Partially Reconstructed B0DπB^0 \to D^* \pi Decays

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    We report measurements of time-dependent decay rates for B0Dπ±B^0 \to D^{*\mp} \pi^\pm decays and extraction of CP violation parameters related to ϕ3\phi_3. We use a partial reconstruction technique, whereby signal events are identified using information only from the primary pion and the charged pion from the decay of the DD^{*\mp}. The analysis uses 140fb1140 {\rm fb}^{-1} of data accumulated at the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ee^{+}e^{-} collider. We measure the CP violation parameters S+=0.035±0.041(stat)±0.018(syst)S^+ = 0.035 \pm 0.041 ({\rm stat}) \pm 0.018 ({\rm syst}) and S=0.025±0.041(stat)±0.018(syst)S^- = 0.025 \pm 0.041 ({\rm stat}) \pm 0.018 ({\rm syst}).Comment: 15 pages, 5 figures. To appear in Physics Letters

    Major vault protein suppresses obesity and atherosclerosis through inhibiting IKK-NF-kappa B signaling mediated inflammation

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    Macrophage-orchestrated, low-grade chronic inflammation plays a pivotal role in obesity and atherogenesis. However, the underlying regulatory mechanisms remain incompletely understood. Here, we identify major vault protein (MVP), the main component of unique cellular ribonucleoprotein particles, as a suppressor for NF-κB signaling in macrophages. Both global and myeloid-specific MVP gene knockout aggravates high-fat diet induced obesity, insulin resistance, hepatic steatosis and atherosclerosis in mice. The exacerbated metabolic disorders caused by MVP deficiency are accompanied with increased macrophage infiltration and heightened inflammatory responses in the microenvironments. In vitro studies reveal that MVP interacts with TRAF6 preventing its recruitment to IRAK1 and subsequent oligomerization and ubiquitination. Overexpression of MVP and its α-helical domain inhibits the activity of TRAF6 and suppresses macrophage inflammation. Our results demonstrate that macrophage MVP constitutes a key constraint of NF-κB signaling thereby suppressing metabolic diseases

    Measurement of gamma gamma -> p p-bar production at Belle

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    A high precision study of the process gamma gamma -> p p-bar has been performed using a data sample of 89/fb collected with the Belle detector at the KEKB e+e- collider. The cross section of p p-bar production has been measured at two-photon center-of-mass (c.m.) energies between 2.025 and 4.0 GeV and in the c.m. angular range of |cos(theta^*)| eta_c -> p p-bar is observed and the product of the two-photon width of the eta_c and its branching ratio to p p-bar is determined.Comment: 20 pages, 9 figures, Fig.1 added, accepted for publication in Phys. Lett.

    Search for lepton flavor violating decays tau- -> l- pi0, l- eta, l- eta'

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    We have searched for lepton flavor violating semileptonic tau decays using a data sample of 153.8/fb accumulated with the Belle detector at the KEKB e+e- collider. For the six decay modes studied, the observed yield is compatible with the estimated background and the following upper limits are set at the 90% confidence level: B(tau- -> e- eta) mu- eta) < 1.5 x 10^-7, B(tau- -> e- pi0) mu- pi0) < 4.1 x 10^-7, B(tau- -> e- eta') mu- eta') < 4.7 x 10^-7. These results are 10 to 64 times more restrictive than previous limits.Comment: 14 pages, 13 figures, RevTex

    Global surveillance of cancer survival 1995-2009: analysis of individual data for 25,676,887 patients from 279 population-based registries in 67 countries (CONCORD-2)

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    BACKGROUND: Worldwide data for cancer survival are scarce. We aimed to initiate worldwide surveillance of cancer survival by central analysis of population-based registry data, as a metric of the effectiveness of health systems, and to inform global policy on cancer control. METHODS: Individual tumour records were submitted by 279 population-based cancer registries in 67 countries for 25·7 million adults (age 15-99 years) and 75,000 children (age 0-14 years) diagnosed with cancer during 1995-2009 and followed up to Dec 31, 2009, or later. We looked at cancers of the stomach, colon, rectum, liver, lung, breast (women), cervix, ovary, and prostate in adults, and adult and childhood leukaemia. Standardised quality control procedures were applied; errors were corrected by the registry concerned. We estimated 5-year net survival, adjusted for background mortality in every country or region by age (single year), sex, and calendar year, and by race or ethnic origin in some countries. Estimates were age-standardised with the International Cancer Survival Standard weights. FINDINGS: 5-year survival from colon, rectal, and breast cancers has increased steadily in most developed countries. For patients diagnosed during 2005-09, survival for colon and rectal cancer reached 60% or more in 22 countries around the world; for breast cancer, 5-year survival rose to 85% or higher in 17 countries worldwide. Liver and lung cancer remain lethal in all nations: for both cancers, 5-year survival is below 20% everywhere in Europe, in the range 15-19% in North America, and as low as 7-9% in Mongolia and Thailand. Striking rises in 5-year survival from prostate cancer have occurred in many countries: survival rose by 10-20% between 1995-99 and 2005-09 in 22 countries in South America, Asia, and Europe, but survival still varies widely around the world, from less than 60% in Bulgaria and Thailand to 95% or more in Brazil, Puerto Rico, and the USA. For cervical cancer, national estimates of 5-year survival range from less than 50% to more than 70%; regional variations are much wider, and improvements between 1995-99 and 2005-09 have generally been slight. For women diagnosed with ovarian cancer in 2005-09, 5-year survival was 40% or higher only in Ecuador, the USA, and 17 countries in Asia and Europe. 5-year survival for stomach cancer in 2005-09 was high (54-58%) in Japan and South Korea, compared with less than 40% in other countries. By contrast, 5-year survival from adult leukaemia in Japan and South Korea (18-23%) is lower than in most other countries. 5-year survival from childhood acute lymphoblastic leukaemia is less than 60% in several countries, but as high as 90% in Canada and four European countries, which suggests major deficiencies in the management of a largely curable disease. INTERPRETATION: International comparison of survival trends reveals very wide differences that are likely to be attributable to differences in access to early diagnosis and optimum treatment. Continuous worldwide surveillance of cancer survival should become an indispensable source of information for cancer patients and researchers and a stimulus for politicians to improve health policy and health-care systems

    Reproducibility in the absence of selective reporting : An illustration from large-scale brain asymmetry research

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    Altres ajuts: Max Planck Society (Germany).The problem of poor reproducibility of scientific findings has received much attention over recent years, in a variety of fields including psychology and neuroscience. The problem has been partly attributed to publication bias and unwanted practices such as p-hacking. Low statistical power in individual studies is also understood to be an important factor. In a recent multisite collaborative study, we mapped brain anatomical left-right asymmetries for regional measures of surface area and cortical thickness, in 99 MRI datasets from around the world, for a total of over 17,000 participants. In the present study, we revisited these hemispheric effects from the perspective of reproducibility. Within each dataset, we considered that an effect had been reproduced when it matched the meta-analytic effect from the 98 other datasets, in terms of effect direction and significance threshold. In this sense, the results within each dataset were viewed as coming from separate studies in an "ideal publishing environment," that is, free from selective reporting and p hacking. We found an average reproducibility rate of 63.2% (SD = 22.9%, min = 22.2%, max = 97.0%). As expected, reproducibility was higher for larger effects and in larger datasets. Reproducibility was not obviously related to the age of participants, scanner field strength, FreeSurfer software version, cortical regional measurement reliability, or regional size. These findings constitute an empirical illustration of reproducibility in the absence of publication bias or p hacking, when assessing realistic biological effects in heterogeneous neuroscience data, and given typically-used sample sizes
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