نتایج جستجو برای: tungsten compounds
تعداد نتایج: 237355 فیلتر نتایج به سال:
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.
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...
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...
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...
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...
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 ...
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...
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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