993 resultados para 665


Relevância:

10.00% 10.00%

Publicador:

Resumo:

本文展现了中国科学院沈阳自动化研究所在并联机器人研究与开发十年来的成果,系统地阐述了并联机器人的机构理论研究、样机开发、应用系统及在研工作,提出了亟待解决的几个问题。随着研究的不断深入,并联机器人将有更广阔的应用前景。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

生活垃圾中含有汞的废弃物、垃圾焚烧已成为西方发达国家最主要的人为大气排放汞源.在中国垃圾填埋是处理城市生活垃圾的最主要方式.利用高时间分辨率大气自动测汞仪对贵阳市郊区高雁垃圾卫生填埋场排气筒气态总汞进行了测定;利用气相色谱与冷原子荧光联用技术测定了排气筒中的单甲基汞和二甲基汞的含量.同时运用大气自动测汞仪与低空白石英玻璃通量箱结合技术高时间分辨率测定了裸露垃圾及填埋场土壤与大气间气态总汞的交换通量.垃圾填埋半年区的排气筒气态总平均浓度为(665.52±291.25)ng/m,与贵阳市某小型燃煤锅炉排放烟气的总汞含量相当,排气筒气体中的单甲基汞

Relevância:

10.00% 10.00%

Publicador:

Resumo:

大气的人为汞释放源研究已经较为广泛,但国内外对垃圾填埋场这一潜在的大气汞释放源还没有重视,尤其是垃圾填埋场释放汞的形态研究较为缺乏。2003 年11 月下旬,对贵阳市一新建的生活垃圾填埋场排放气体中的总汞( TGM) 、单甲基汞(MMHg) 、二甲基汞(DMHg) 进行了初步的研究。结果显示填埋半年、填埋一年与填埋两年的垃圾填埋场排气筒气体中总汞浓度分别为665. 52 ±291. 25 ng/ m3 ( n = 305) 、25. 6 ±3. 2 ng / m3 ( n = 13) 、14. 5±1. 8 ng/ m3 ( n = 28) ;填埋半年与填埋两年的垃圾填埋场排气筒气体中单甲基汞浓度分别为2. 06 ±1. 82 ng/ m3( n = 11) 、0. 18 ±0. 06 ng/ m3 ( n = 2) ,二甲基汞浓度为9. 45 ±5. 18 ng/ m3 ( n = 12) 。这一结果初步说明垃圾填埋场不仅是大气总汞的释放源类型之一,也是大气中毒性更强的单甲基汞与二甲基汞的释放源之一。

Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A new post-grafting process, consisting of two steps of substrate preparation and sol - gel post-grafting, has been developed to prepare titanium-doped mesoporous SBA-15 material with a double-layered structure and locally concentrated titanium content at the inner pore surface. With this novel technique, the single phased and originally ordered mesostructures can be well conserved; in the conventional direct synthesis they can be partially damaged when the frameworks are doped with high content heteroatoms. Titanium species exist in an isolated, tetrahedral structure and are localized at the pore surface; this is beneficial to both reactant access and product release. Characterization with XRD, N-2 adsorption/desorption isotherms, HREM/ EDS, ICP, UV - Vis, and the newly developed UV - Raman spectroscopy confirm these results. Preliminary catalytic tests with the selective epoxidation of cyclohexene show good catalytic activity. Among them, sample TiSBA-15-10 with a Si : Ti molar ratio of 10 shows a TON value of 75 and a highest product ( epoxide) yield of 55%.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Cashman, N. (2009). 'Politics, Passion, Prejudice: Alice Childress's Wedding Band: A Love/Hate Story in Black and White', Journal of American Studies, 43, 3, pp. 407?423 Sponsorship: APRS

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Williams, Mike, 'Why ideas matter in International Relations: Hans Morgenthau, Classical Realism, and the Moral Construction of Power Politics', International Organization (2004) 58(4) pp.633-665 RAE2008

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Wydział Filologii Polskiej i Klasycznej: Pracownia Innowacji Dydaktycznych

Relevância:

10.00% 10.00%

Publicador:

Resumo:

http://www.archive.org/details/isaacmccoycarlyi012072mbp

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Gaussian factor models have proven widely useful for parsimoniously characterizing dependence in multivariate data. There is a rich literature on their extension to mixed categorical and continuous variables, using latent Gaussian variables or through generalized latent trait models acommodating measurements in the exponential family. However, when generalizing to non-Gaussian measured variables the latent variables typically influence both the dependence structure and the form of the marginal distributions, complicating interpretation and introducing artifacts. To address this problem we propose a novel class of Bayesian Gaussian copula factor models which decouple the latent factors from the marginal distributions. A semiparametric specification for the marginals based on the extended rank likelihood yields straightforward implementation and substantial computational gains. We provide new theoretical and empirical justifications for using this likelihood in Bayesian inference. We propose new default priors for the factor loadings and develop efficient parameter-expanded Gibbs sampling for posterior computation. The methods are evaluated through simulations and applied to a dataset in political science. The models in this paper are implemented in the R package bfa.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This work comprises accurate computational analysis of levitated liquid droplet oscillations in AC and DC magnetic fields. The AC magnetic field interacting with the induced electric current within the liquid metal droplet generates intense fluid flow and the coupled free surface oscillations. The pseudo-spectral technique is used to solve the turbulent fluid flow equations for the continuously dynamically transformed axisymmetric fluid volume. The volume electromagnetic force distribution is updated with the shape and position change. We start with the ideal fluid test case for undamped Rayleigh frequency oscillations in the absence of gravity, and then add the viscous and the DC magnetic field damping. The oscillation frequency spectra are further analysed for droplets levitated against gravity in AC and DC magnetic fields at various combinations. In the extreme case electrically poorly conducting, diamagnetic droplet (water) levitation dynamics are simulated. Applications are aimed at pure electromagnetic material processing techniques and the material properties measurements in uncontaminated conditions.