نتایج جستجو برای: tungsten compounds

تعداد نتایج: 237355  

Journal: :Chemical communications 2009
Daniela Buccella Gerard Parkin

p-tert-Butyltetrathiatetramercaptocalix[4]arene, [S(4)Calix(Bu(t))(SH)(4)], reacts with Mo(PMe(3))(6), W(PMe(3))(4)(eta(2)-CH(2)PMe(2))H and Ni(PMe(3))(4) to yield molybdenum, tungsten and nickel compounds in a sulfur-rich coordination environment.

2014
Vladislav Kulikov Gerd Meyer

Three new compounds, (GuaH)4[W10O32](H2O)4 (1), (ThbH)3(H3O)[(W10O32](H2O)7.5 (2) and (ThbH)2[W6O19](H2O)2 (3) (GuaH = guaninium, thbH = theobrominium) were synthesized in acidified acetonitrile solutions. The polyoxotungstates in all of these compounds are surrounded by an organic matrix consisting of protonated purine bases and water molecules. The distinctive structural arrangement of the ar...

2014
Chuan Wang Hisashi Yamamoto

The first catalytic, highly C3-selective, stereosepecific ring-opening reaction of 2,3-epoxy alcohols and 2,3-epoxy sulfonamides has been accomplished. This process was efficiently promoted by W-salts, and the developed method was applicable to various epoxides with diverse N- and O-nucleophiles affording the products in good to excellent yields (up to 95%) and generally with high regioselectiv...

F. Salimi M. Masteri-Farahani, M. Mehdi Kashani Motlagh M. Sadeghi Y. Abdollahi

Two new heterogenized epoxidation nanocatalysts based on molybdenum and tungsten compounds were prepared withcovalent grafting of MCM-41 with 3-aminoropropyl trimethoxysilane and subsequent reaction with diphenylphosphinobenzaldehyde and complexation with M (Mo, W)O2(acac)2. X-ray diffraction and nitrogen sorption analyses revealed the preservation of the textural properti...

2010
N. Endstrasser F. Brochard V. Rohde M. Balden T. Lunt S. Bardin J-L. Briançon R. Neu Nikolaus Endstrasser

2D dust particle trajectories are extracted from fast framing camera videos of ASDEXUpgrade (AUG) by a new timeand resource-efficient code and classified into stationary hot spots, single-frame events and real dust particle fly-bys. Using hybrid global and local intensity thresholding and linear trajectory extrapolation individual particles could be tracked up to 80 ms. Even under challenging c...

Journal: :journal of biomedical physics and engineering 0
m. r. aghamiri associate professor of medical physics, medical physics & engineering department, school of medicine, shahid beheshti university of medical sciences, tehran, iran s. m. j. mortazavi professor of medical physics, medical physics & engineering department, school of medicine, shiraz university of medical sciences, shiraz, iran m. tayebi master student of radiobiology and radiation protection, shahid beheshti university of medical sciences, tehran, iran m. a. mosleh-shirazi assistant professor of medical physics, radiotherapy department, school of medicine, shiraz university of medical sciences, shiraz, iran h. baharvand assistant professor of polymer chemistry, iran polymer institute, tehran, iran a. tavakkoli-golpayegani assistant professor of medical engineering (biomechanics), medical physics & engineering department, school of medicine, shiraz university of medical sciences, shiraz, iran

background: lead-based radiation shields are widely used in radiology departments to protect both workers and patients from any unnecessary exposure to ionizing radiation. recently there has been a great deal of concern expressed about the toxicity of lead. human lead toxicity is well documented. in that light, production of environmentally-friendly lead-free radiation shields with less weight ...

Journal: :iranian journal of medical physics 0
lida gholamkar department of medical radiation engineering, science and research branch, islamic azad university, tehran, iran, mahdi sadeghi medical physics department, school of medicine, iran university of medical sciences, tehran, iran ali asghar mowlavi physics department, school of sciences, hakim sabzevari university, sabzevar, iran. ictp, associate federation scheme, medical physics field, trieste, italy. mitra athari department of medical radiation engineering, science and research branch, islamic azad university, tehran, iran,

introduction one of the best methods in the diagnosis and control of breast cancer is mammography. the importance of mammography is directly related to its value in the detection of breast cancer in the early stages, which leads to a more effective treatment. the purpose of this article was to calculate the x-ray spectrum in a mammography system with monte carlo codes, including mcnpx and mcnp5...

A. Tavakkoli-Golpayegani B. Zeinali-Rafsanjani H. Baharvand M. A. Mosleh-Shirazi M. R. Aghamiri, M. Tayebi S. M. J. Mortazavi

Background: Lead-based radiation shields are widely used in radiology departments to protect both workers and patients from any unnecessary exposure to ionizing radiation. Recently there has been a great deal of concern expressed about the toxicity of lead. Human lead toxicity is well documented. In that light, production of environmentally-friendly lead-free radiation shields with less weight ...

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