نتایج جستجو برای: cr

تعداد نتایج: 45657  

2017

Herpes Zoster (HZ) is a segmental erup on of grouped vesicles that are confined to a dermatome. There is dermatomal distribu on of skin rash, which is unilateral. When two non contagious dermatomes are involved, if affected bilaterally, it is called HZ duplex bilateralis; if unilaterally, unilateralis. HZ duplex bilateralis is extremely rare in immunocompetent children. This report describes a ...

2010
John T. Wasson Alan E. Rubin

In section many low-FeO CR chondrules are surrounded by rings of metal; this metal-cladding seems to have formed during chondrule melting events as films of metal that wetted the surface. Electron microprobe studies show that in each ring the metal is very uniform in composition, consistent with efficient mixing during formation of the metal film. In contrast the mean Ni contents of 13 differen...

2004
TAKASHI NOIRI

In this paper, we introduce the notion of weakly e-continuous functions in topological spaces. Weak s-contlnulty and subweak continuity due to Rose [i] are independent of each other and are implied by weak continuity due to Levlne [2]. It is shown that weakly e-continuous surjections preserve connected spaces and that weakly e-contlnuous functions into regular spaces are continuous. Corollary i...

2017
BANG-YEN CHEN Bang-Yen Chen

© Université Paul Sabatier, 1981, tous droits réservés. L’accès aux archives de la revue « Annales de la faculté des sciences de Toulouse » (http://picard.ups-tlse.fr/~annales/) implique l’accord avec les conditions générales d’utilisation (http://www.numdam.org/legal.php). Toute utilisation commerciale ou impression systématique est constitutive d’une infraction pénale. Toute copie ou impressi...

Journal: :Nano letters 2005
Q Wang Q Sun P Jena Y Kawazoe

Using first-principles theory, we predict ferromagnetism in Cr-doped GaN nanowires irrespective of the sites that the Cr atoms occupy. This is in contrast to Mn-doped GaN nanowires in which the magnetic coupling between the Mn atoms is sensitive to the Mn--Mn and Mn--N distances, although the ground state of Mn-doped GaN nanowires is ferromagnetic. Each Cr atom carries a magnetic moment of abou...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2010
Tetsuo Inui Kazuhiro Fujita Masaru Kitano Toshihiro Nakamura

A simple method using solid-phase extraction combined with metal furnace atomic absorption spectrometry was developed for the determination of Cr(III) and Cr(VI) at sub-ppb levels in water. A 500-ml water sample was adjusted to pH 3 with nitric acid and then passed through an iminodiacetate extraction disk placed on a cation-exchange extraction disk at a flow rate of 20-40 ml min(-1) for concen...

Journal: :Reviews of environmental contamination and toxicology 2015
Nezha Tahri Joutey Hanane Sayel Wifak Bahafid Naïma El Ghachtouli

Chromium has been and is extensively used worldwide in multiple industrial processes and is routinely discharged to the environment from such processes. Therefore, this heavy metal is a potential threat to the environment and to public health, primarily because it is non-biodegradable and environmentally persistent. Chromium exists in several oxidation states, the most stable of which are triva...

Journal: :Environmental science. Processes & impacts 2015
Elizabeth C Butler Lixia Chen Colleen M Hansel Lee R Krumholz Andrew S Elwood Madden Ying Lan

Hexavalent chromium (Cr(vi), present predominantly as CrO4(2-) in water at neutral pH) is a common ground water pollutant, and reductive immobilization is a frequent remediation alternative. The Cr(iii) that forms upon microbial or abiotic reduction often co-precipitates with naturally present or added iron (Fe), and the stability of the resulting Fe-Cr precipitate is a function of its mineral ...

2015
Alma Rosa Netzahuatl-Muñoz María del Carmen Cristiani-Urbina Eliseo Cristiani-Urbina Heidar-Ali Tajmir-Riahi

The present study investigated the kinetics, equilibrium and thermodynamics of chromium (Cr) ion biosorption from Cr(VI) aqueous solutions by Cupressus lusitanica bark (CLB). CLB total Cr biosorption capacity strongly depended on operating variables such as initial Cr(VI) concentration and contact time: as these variables rose, total Cr biosorption capacity increased significantly. Total Cr bio...

Journal: :Carbohydrate polymers 2014
Fernando A Bertoni Sebastian E Bellú Juan C González Luis F Sala

Selective oxidation of carboxylate groups present in alginic acid by Cr(VI) affords CO2, oxidized alginic acid, and Cr(III) as final products. The redox reaction afforded first-order kinetics in [alginic acid], [Cr(VI)], and [H(+)], at fixed ionic strength and temperature. Kinetic studies showed that the redox reaction proceeds through a mechanism which combines Cr(VI)→Cr(IV)→Cr(II) and Cr(VI)→...

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