33,874 research outputs found
Lattice Boltzmann modeling of multiphase flows at large density ratio with an improved pseudopotential model
No full textOwing to its conceptual simplicity and computational efficiency, the pseudopotential multiphase lattice Boltzmann (LB) model has attracted significant attention since its emergence. In this work, we aim to extend the pseudopotential LB model to simulate multiphase flows at large density ratio and relatively high Reynolds number. First, based on our recent work [Q. Li, K. H. Luo, and X. J. Li, Phys. Rev. E 86, 016709 (2012)], an improved forcing scheme is proposed for the multiple-relaxation-time pseudopotential LB model in order to achieve thermodynamic consistency and large density ratio in the model. Next, through investigating the effects of the parameter a in the Carnahan-Starling equation of state, we find that the interface thickness is approximately proportional to 1/a?. Using a smaller a will lead to a wider interface thickness, which can reduce the spurious currents and enhance the numerical stability of the pseudopotential model at large density ratio. Furthermore, it is found that a lower liquid viscosity can be gained in the pseudopotential model by increasing the kinematic viscosity ratio between the vapor and liquid phases. The improved pseudopotential LB model is numerically validated via the simulations of stationary droplet and droplet oscillation. Using the improved model as well as the above treatments, numerical simulations of droplet splashing on a thin liquid film are conducted at a density ratio in excess of 500 with Reynolds numbers ranging from 40 to 1000. The dynamics of droplet splashing is correctly reproduced and the predicted spread radius is found to obey the power law reported in the literatur
q-Differential equations for q-classical polynomials and q-Jacobi-Stirling numbers
No full textWe introduce, characterise and provide a combinatorial interpretation for the so-called q-Jacobi–Stirling numbers.
This study is motivated by their key role in the (reciprocal) expansion of any power of a second order
q-differential operator having the q-classical polynomials as eigenfunctions in terms of other even order operators,
which we explicitly construct in this work. The results here obtained can be viewed as the q-version of
those given by Everitt et al. and by the first author, whilst the combinatorics of this new set of numbers is a
q-version of the Jacobi–Stirling numbers given by Gelineau and the second author
Structure characterization and tribological study of magnetron sputtered nanocomposite nc-TiAlV(N, C)/a-C coatings
No full textGrown by reactive unbalanced magnetron sputtering in a mixed N2 and CH4 gaseous medium, heterogeneous nanocomposite coatings in the Ti-Al-V-N-C system show extraordinarily excellent tribological performance of coated machining tools. Using analytical high resolution TEM, EELS, FEG-SEM, XRD, and Raman spectroscopy, this paper reports detailed structural and chemical characterization of the coatings grown at various CH4: N2 ratios. Meanwhile, the mechanical and tribological properties were also measured, including hardness, Young’s modulus, residual stress and the dry-sliding friction and wear at varying environmental humidity. When CH4 gas was introduced in the deposition, the structure of the coatings has been found to experience a change from nano-scale TiAlN-VN multilayer architecture to a complex mixture of columnar grains of nc-TiAlV(N,C)/a-C nanocomposites and inter-column network of sp2-type amorphous carbon. Carbon incorporation and segregation also shows remarkable influence on the columnar growth model by leading to finer grain size. As compared to the carbon-free nitride coating, the nanocomposite coatings showed substantially reduced residual stress owing to the free-carbon precipitation, whereas the coatings maintained comparable hardness to the carbon-free TiAlN/VN. Their tribological properties were found to be strongly dependent on the environment. In humid air at RH > 30%, the coatings showed low friction coefficient less than 0.4 and extremely low wear rate at a scale of ~10-17 m3N-1m-1
q-поліноми Апостола-Ейлера та q-знакозмінні суми
No full textBasic properties are established and generating functions are obtained for the q -Apostol–Euler polynomials. We define q -alternating sums and obtain q -extensions of some formulas from Integral Transform. Spectr. Funct., 20, 377–391 (2009). We also deduce an explicit relationship between the q -Apostol–Euler polynomials and the q -Hurwitz–Lerch zeta-function.Встановлено основні властивості та твірні функції q-полiномiв Апостола-Ейлера. Визначено q-знакозмінні суми та отримано q-продовження деяких формул з [Integral Transform. Spec. Funct.-2009.-20.-P. 377-391]. Виведено також явне співвідношення між q-поліномами Апостола-Ейлера i q-дзета-функцією Хурвіца-Лерча.This research was supported by Natural Science Foundation Project of Chongqing, China under GrantCSTC2011JJA00024, Research Project of Science and Technology of Chongqing Education Commission, China underGrant KJ120625, Fund of Chongqing Normal University, China under Grant 10XLR017 and 2011XLZ07 and the PhDProgram Scholarship Fund of ECNU 2009 of China under Grant 2009041
q-поліноми Апостола-Ейлера та q-знакозмінні суми
No full textBasic properties are established and generating functions are obtained for the q -Apostol–Euler polynomials. We define q -alternating sums and obtain q -extensions of some formulas from Integral Transform. Spectr. Funct., 20, 377–391 (2009). We also deduce an explicit relationship between the q -Apostol–Euler polynomials and the q -Hurwitz–Lerch zeta-function.Встановлено основні властивості та твірні функції q-полiномiв Апостола-Ейлера. Визначено q-знакозмінні суми та отримано q-продовження деяких формул з [Integral Transform. Spec. Funct.-2009.-20.-P. 377-391]. Виведено також явне співвідношення між q-поліномами Апостола-Ейлера i q-дзета-функцією Хурвіца-Лерча.This research was supported by Natural Science Foundation Project of Chongqing, China under GrantCSTC2011JJA00024, Research Project of Science and Technology of Chongqing Education Commission, China underGrant KJ120625, Fund of Chongqing Normal University, China under Grant 10XLR017 and 2011XLZ07 and the PhDProgram Scholarship Fund of ECNU 2009 of China under Grant 2009041
Fig. 1. – Primulina dongguanica F. Wen, Y. G. Wei & R. Q. Luo. A in Primulina dongguanica F. Wen, Y. G. Wei & R. Q. Luo (Gesneriaceae), a new species from South China
No full textFig. 1. – Primulina dongguanica F. Wen, Y. G. Wei & R. Q. Luo. A. Habit; B. Opened corolla with stamens and staminodes; C. One calyx lobe; D. Calyx and pistil. [Fang Wen 100803, IBK] [Drawing: Wen-Hong Lin]Published as part of Wen, Fang & Wei, Yi-Gang, 2014, Primulina dongguanica F. Wen, Y. G. Wei & R. Q. Luo (Gesneriaceae), a new species from South China, pp. 9-19 in Candollea 69 (1) on page 11, DOI: 10.15553/c2014v691a2, http://zenodo.org/record/576184
Rosa tomurensis L. Luo, C. Yu & Q. X. Zhang
No full textRosa tomurensis L. Luo, C. Yu & Q. X. Zhang (Figures 3, 4, 5) Type: — CHINA. Xinjiang Uygur autonomous region, Akesu Prefecture, Wensu County, Tuomuerfeng Natural Preservation Areas, in river valleys, ca. 1800m, 10 June 2017, L. Luo, C. Yu, Y. J. Sui, F. Yang & S. Zhao 171022 (holotype BJFC00107674!). Diagnosis: — R. tomurensis is different from R. laxa in the following characteristics: prickles are rare, single prickles are larger, and the tip of prickles is not curved significantly; leaf blade apex serrate only, subbase one-third entire; flowers often solitary, and single flowers are larger than R. laxa; receptacles purplish red, occasionally green; pedicels very long, purplish red or green; sepals are purplish red or green; hips are larger than R. laxa, often pendulous, hip apex without short neck; hip pedicels slightly inflated at base; sepals abaxially, receptacle and pedicel glandular or glandless together, the glands in the pedicel sometimes shed at anaphase. (Table 2). Description: —Shrubs, erect, 2.5–3 m tall, basal branching. Branchlets slender, brownish red; branchial spines are rare, scattered, rarely opposite, pale yellow and white, unequal in length, slender, broad at base, apex slightly downward curved. Leaflets 5–9, usually 7, elliptic, obovoid, ovoid or oblong, 0.6–2 × 0.5–1 cm, abaxially sparsely pilose, adaxially smooth; leaf margin simple serrate, often entire subbase one-third. Stipules usually wider, base mostly adnate to petiole, free portion ovate, triangulate, margin glandular spot. Flowers often solitary, sometimes 2–3 in corymbose cymes, (3) 3.5–6.5 (7) cm in diam; pedicel 1.5–3.5 cm, pedicel and calyx tube glabrous or tomentose and sparsely glandular hairs; bracts ovate, margin glandular teeth, abaxially with distinct midrib and lateral veins; sepals long lanceolate, margin entire, apex elongated widened into appendages, abaxially glandular and densely tomentose, adaxially densely pubescent, margin more densely; petals white, sparse pink,or pale pink, at bud stage, petal tips are often pink or pale pink. Hip subglobose or ovoid, red, shiny, 1–2.1cm in diam, 1.5–2 cm long, sepals persistent and spreading; fruit pedicel straight or bent. Distribution and habitat: —This species is produced in the Tuomuerfeng Natural Preservation Areas of Wensu County in Aksu Perfecture, the Pamir Plateau Mountain Area of Kizilsu Kirgiz Autonomous Prefecture, Tajik Autonomous County of Taxkorgan in Kashgar Prefecture and the south slope of Duku Highway, Xinjiang Uygur Autonomous Region. It borns in arid mountains, river valleys and riparian thickets, at elevations between 1700 m and 3000 m. The associated woody plants in this area are R. laxa, R. albertii, Berberis sp., Caragana sp., etc. Phenology: —Flowering from June to July, fruiting from August to October. Etymology: —The specific epithet refers to the distribution where the new species was first discovered. Paratypes: — CHINA. Xinjiang Uygur autonomous region, Akesu Prefecture, Wensu County, Tuomuerfeng Natural Preservation Areas, in river valleys, ca. 1800m, 24 September 2017, L. Luo, C. Yu, Y. J. Sui, F. Yang & S. Zhao 171023 (BJFC00107688!); the same locality, 8 June 2017, L. Luo, C. Yu, Y. J. Sui, F. Yang & S. Zhao 171024 (BJFC00107671!). Conservation status: —Based on currently available data, the species should be assigned to the ‘Data Deficient’ (DD) category of IUCN (2022). There is little human interference in this species’ distribution areas, so these populations are not easy to be destroyed.Published as part of Deng, Tong, Luo, Le, Yu, Chao, Zhang, Qi-Xiang, Liu, Xue-Sen & Deng, Ze-Yi, 2022, Rosa tomurensis, a new species of Rosa (Rosaceae) from China, pp. 169-177 in Phytotaxa 556 (2) on pages 174-175, DOI: 10.11646/phytotaxa.556.2.6, http://zenodo.org/record/696599
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Network Q
No full textA press release from Network Q announcing that they will begin featuring Brian McNaught, a gay columnist and author, for a monthly segment
Network Q
No full textA press release from Network Q announcing that they will begin featuring Brian McNaught, a gay columnist and author, for a monthly segment
The 2008 Beijing Olympics opening ceremony: visual insights into China's soft power.
No full textAs sports media events, and especially Olympic Games, can be considered a public relations instrument, the 2008 Beijing Olympics allowed China to showcase its rapid economic development to the rest of the world and win respect and favour internationally. This paper explores how China used the Olympic Games as a soft power and international communication strategy by analysing particular moments and images of the 2008 opening ceremony. The ritual of the opening ceremony represents a concentration of features, qualities and messages that combine the local and global, the culturally specific and universal, in a complex production. For the purpose of our analysis, we adopted a thematic approach and focused on the images related to messages such as ‘harmony and peace’, ‘unity’ and ‘power and innovation’. These themes are mainly related to the revival of Chinese traditional cultural values based on Confucianism whose central element is the value of harmony
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