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Quark-novae in neutron star - white dwarf binaries: a model for luminous (spin-down powered) sub-Chandrasekhar-mass Type Ia supernovae?

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Research in Astronomy and Astrophysics 2013年第4期13卷 435-464页

作者： Rachid Ouyed jan Staff Department of Physics and Astronomy University of Calgary2500 University Drive NW Department of Physics and Astronomy Louisiana State University

We show that, by appealing to a Quark-Nova （QN） in a tight binary system containing a massive neutron star and a CO white dwarf （WD）, a Type Ia explosion could occur. The QN ejecta collides with the WD, driving a shock that triggers carbon burning under degenerate conditions （the QN-Ia）. The conditions in the compressed low-mass WD （MwD 〈 0.9 M） in our model mimic those of a Chandrasekhar mass WD. The spin-down luminosity from the QN compact remnant （the quark star） pro- vides additional power that makes the QN-Ia light-curve brighter and broader than a standard SN-Ia with similar 56Ni yield. In QNe-Ia, photometry and spectroscopy are not necessarily linked since the kinetic energy of the ejecta has a contribution from spin-down power and nuclear decay. Although QNe-Ia may not obey the Phillips relationship, their brightness and their relatively ＂normal looking＂ light-curves mean they could be included in the cosmological sample. Light-curve fitters would be con- fused by the discrepancy between spectroscopy at peak and photometry and would correct for it by effectively brightening or dimming the QNe-Ia apparent magnitudes, thus over- or under-estimating the true magnitude of these spin-down powered SNe-Ia. Contamination of QNe-Ia in samples of SNe-Ia used for cosmological analyses could systematically bias measurements of cosmological parameters if QNe-Ia are numerous enough at high-redshift. The strong mixing induced by spin-down wind combined with the low 56Ni yields in QNe-Ia means that these would lack a secondary maximum in the/-band despite their luminous nature. We discuss possible QNe-Ia progenitors.

关键词： stars evolution - stars binary - stars neutron - stars white dwarfs - supernovae general

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A fiducial approach to the nonparametric deconvolution problem:The discrete case

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Science China Mathematics 2024年第11期67卷 2653-2670页

作者： Yifan Cui jan Hannig Center for Data Science Zhejiang UniversityHangzhou 310058China Department of Statistics and Operations Research University of North Carolina at Chapel HillChapel HillNC 27599USA

Fiducial inference is applied to nonparametric g-modeling in the discrete *** propose a computationally efficient algorithm to sample from the fiducial distribution and use the generated samples to construct point estimates and confidence *** study the theoretical properties of the fiducial distribution and perform extensive simulations in various *** proposed approach gives rise to good statistical performance in terms of the mean squared error of point estimators and coverage of confidence ***,we apply the proposed fiducial method to estimate the probability of each satellite site being malignant using gastric adenocarcinoma data with 844 patients.

关键词： confidence intervals empirical Bayes fiducial inference nonparametric deconvolution

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Experimental Study of Aerodynamic Behavior in Wind Tunnels with Ornithopter and Plane Models

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Journal of Thermal Science 2006年第1期15卷 54-58页

作者： Marie-Francoise SCIBILIA jan WOJCIECHOWSKI Centre National de la Recherche Scientiflque France. Institute of Aeronautics and Applied Mechanics Warsaw University of Technology Poland.

There are similarities between planes and birds. In fact aerodynamics bases are the same. In order to make some comparisons, this paper presents two series of experiments ： one in a wind tunnel with an omithopter model for measurements of aerodynamic forces with flapping wings. The wing movement has two degrees of freedom flapping around the longitudinal axis of the model and feathering around the wing axis. Measurements of aerodynamic forces： rift and drag in static case averaging values during many cycles of movement and in dynamic case have been performed. The other part of the paper concerns velocity and turbulence measurements on a metal plane wall jet in a wind tunnel with and without a rough surface, with and without acoustic vibrations in order to simulate a plane wing. Aerodynamic characteristics have been obtained in all cases.

关键词： wind tunnel aerodynamics characteristics ornithopter model plane wall jet.

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APRINDINE IN PREMATURE VENTRICULAR CONTRACTIONS POST MYOCARDIAL INFARCTION

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Chinese Medical Journal 1981年第8期94卷 518-522页

作者： jan Lessem Heart Section Department of MedicineMalm General HospitalSweden

The effectiveness of aprindine in reducingventricular extrasystoles is investigated in 17patients suffering from acute myocardial infarc-tion and l with ventricular tachycardia episodebut no evidence of acute *** is foundthat aprindine is not only effective against ven-tricular extrasystoles when given orally topatients with ischemic heart disease but also isa drug of choice for premature ventricular ***,the side effects of the drug,particularly agranulocytosis,will probably keepthe drug from being the one of choice in chro-nic premature ventricular contractions.

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Analysis of underground fires in Polish hard coal mines

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Journal of China University of Mining and Technology 2008年第3期18卷 332-336页

作者： WACHOWICZ jan Central Mining Institute (GIG) Plac Gwarków 1 Katowice 40-167 Poland

In the period of the first twenty years after World War II the number of fires in Polish hard coal mines reached annually the value of several thousands of cases. About 80% of fires constituted spontaneous fires. Investigations into the development of new methods of fire hazard prediction and implementation of new methods and means of fire prevention as well as the introduction of prohibition concerning the use of products manufactured of combustible organic materials in underground mine workings re-duced considerably the hazard of underground fire rise. The worked out at the Central Mining Institute (GIG) new method of un-derground fire prediction allows the correct selection of fire prevention means. The introduction into common use of fire-resistant conveyor belts, the main factor giving rise to spontaneous fires, and methods of assessment of their fire resistance eliminated prac-tically the fire hazard. These activities contributed in an efficient way to the reduction of the number of underground fires to a sat-isfactory level.

关键词： spontaneous fires open fires coal self-heating fire-resistant conveyor belts flammability of conveyor belts fire-resistant materials

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Microstructure and mechanical properties of WC-20wt% Co/ZrO_2(3Y)cermet composites

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Journal of University of Science and Technology Beijing 2006年第2期13卷 174-177页

作者： Lin An Jingtao Han jan Chen Materials Science and Engineering School University of Science and Technology Beijing Beijing 100083 China Shougang Dongxing Industry Corporation Yantan 264006 China

The cermet composites WC-20wt%Co/ZrO2（E6）with four different comtents of ZrO2（3Y）were prepared by normal vacuum sinter processing;the optical microscope and SEMwere used to characterize their *** *** strength and impact toughness of the specimens were *** experimental results show that ZrO2（3Y） particles in WC-20wt%Co matrix are sphcrical particles in different sizes which are distributed uniformly in Co phases and WC phases,the bending strength and impact toughness of the WC-20wt%Co cermet composites added ZrO2（3Y）improve *** the hardness values have little change.

关键词： ZrO2(3Y) cermet composites mechanical properties microstructure normal vacuum sinter

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Molecular Networks Regulating Meristem Homeostasis

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Molecular Plant 2018年第7期11卷 883-885页

作者： jan Traas Laboratoire de Reproduction et Developpement des Plantes INRA CNRS ENSL UCB Lyon I Universite de Lyon 46 allee d'ltalie 69364 Lyon Cedex 07 France

The shoot apical meristem （SAM）, which produces all the aerial parts of the plant, plays a major role in the establish- ment of plant architecture. In many higher plants, the SAM has a stereotypic organization in zones with different func- tions. At the summit of the dome-shaped meristem is a popu- lation of stem cells （called the central zone）, required for meristem maintenance. Part of the cells produced by the central zone will enter a differentiation pathway and their descendants will serve as founders for the stems and lateral organs at the meristem periphery （or peripheral zone）. During the last decades, much of the research on the SAM has focused on three major signaling cascades required for its function：

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Some recent advances in fluidized-bed polymerization technology

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Particuology 2010年第6期8卷 578-581页

作者： jan van Egmond Mike Tilston Union Carbide Corporation a subsidiary of The Dow Chemical CompanyFreeportTX 77541USA

The fluidized-bed polymerization process has been in use for decades. From the manufacturer＇s perspective it is desirable to improve technology without major modification of the reactor system. Therefore, in order to meet the demand for new products or more efficient reactor operation, manufacturers prefer to improve the catalyst system in the most cost effective manner. Using polypropylene production as an example, some recent advances in fluidized-bed polymerization technology are presented.

关键词： Fluidized bed Polymerization Polypropylene Catalyst Donor Kinetics

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Behaviour of cranes(family Gruidae)mirrors their phylogenetic relationships

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Avian Research 2021年第3期12卷 285-295页

作者： Nela Nováková jan Robovský Faculty of Science University of South BohemiaBranišovská176037005ČeskéBudějoviceCzechia

Background:The behavioural repertoire of every species evolved over time and its evolution can be traced through the phylogenetic relationships in distinct ***(family Gruidae)represent a small,old,monophyletic group with well-corroborated phylogenetic relationships on the species level,and at the same time they exhibit a complex and well-described behavioural ***:We therefore investigated the evolution of behavioural traits of cranes in a phylogenetic context using several phylogenetic approaches and two types of trait *** cranes exhibit more than a hundred behavioural displays,almost one third of which may be phylogenetically ***:More than half of the analysed traits carry a significant phylogenetic *** ancestor of cranes already exhibited a quite complex behavioural repertoire,which remained unchanged in Balearicinae but altered greatly in Gruinae,specifically by the shedding of traits rather than their *** scoring has an influence on results within the Gruinae,primarily in genera Bugeranus and ***:Albeit the behavioural traits alone cannot be used for resolving species-level relationships within the Gruidae,when optimized on molecular tree,they can help us to detect interesting evolutionary transformations of behaviour repertoire within *** Limpkin(Aramus guarauna)seems to be the most enigmatic species and should be studied in detail for its behavioural repertoire,which may include some precursors of crane behavioural traits.

关键词： Ancestral behavioural repertoire Evolution Phylogenetic signal

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CFB cyclones at high temperature:Operational results and design assessment

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Particuology 2008年第3期6卷 149-156页

作者： Raf Dewil jan Baeyens Bart Caerts Department of Chemical Engineering Associated Faculty of Technology and Bio-sciencesCampus De NayerKatholieke Universiteit LeuvenJan De Nayerlaan 5B-2860 Sint-Katelijne-WaverBelgium Department of Chemical Engineering University of BirminghamEdgbastonBirmingham B15 2TTUnited Kingdom Department of Chemical Engineering Katholieke Universiteit LeuvenWillem De Croylaan 46B-3001 HeverleeBelgium

Pressure drop and cut size measurements are reported for a full scale cyclone operating within a 58 MWth CFB-combustor unit at 775 ℃. The paper reviews the vast number of equations to calculate the pressure drop and separation efficiency of cyclones, generally for operation at ambient temperature and at low Cs [〈0.5]. None of the literature correlations predicts the pressure drop with a fair accuracy within the range of experimental operating conditions. The cut size d50 can be estimated using direct empirical methods or using the Stokes number, Stk50. Both methods were used to compare measured and predicted values of d50. With the exception of Muschelknautz and Krambrock, none of the equations made accurate predictions. Finally, an alternative method to determine the friction factor of the pressure drop equation （Euler number, Eu） and of the cut size is proposed. The Eu number is determined from the geometry of common cyclones, and the derived value of Stk50 defines more accurate cut sizes. The remaining discrepancy of less than 5%, when compared with the measured values, is tentatively explained in terms of a reduced cyclone diameter due to the solids layer formed near its wall. Further measurements, mostly using positron emission particle tracking, elucidate the particle motion in the cyclone and both tracking results and the influence of the particle movement on Eu and Stk50 will be discussed in a follow-up paper.

关键词： Cyclone High loading High temperature Combustor

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