نتایج جستجو برای: major ion chemistry
تعداد نتایج: 911280 فیلتر نتایج به سال:
The major foible of dental ceramics is their brittle nature. Therefore, the producers of these materials have focused on the “strength” issue. A method of increasing strength is ion exchange on porcelain surface which leads to formation of a compressive crust that opposing forces should overcome before developing a crack. In current study, ion exchange in two types of porcelain, Ceramco II wh...
The recent discovery of ArH+ in the interstellar medium has awakened the interest in the chemistry of this ion. In this work, the ion-molecule kinetics of cold plasmas of Ar/H2 is investigated in glow discharges spanning the whole range of [H2]/([H2]+[Ar]) proportions for two pressures, 1.5 and 8 Pa. Ion concentrations are determined by mass spectrometry, and electron temperatures and densities...
For exploration of quantum effects with hybrid atom-ion systems, reaching ultracold temperatures is the major limiting factor. In this work, we present results on numerical simulations trapped ion buffer gas cooling using an atomic in a large number experimentally realistic scenarios. We explore suppression micromotion-induced heating through optimization trap parameters for various radio-frequ...
Gas-phase ion chemistry is an area in mass spectrometry that has received much research interest since the mid fifties of the last century. Although the focus of mass spectrometric research has shifted the last twenty years largely to life science studies, including proteomics, genomics and metabolomics, there are still several groups in the world active in gas-phase ion chemistry of both posit...
As a result, medicinal chemistry, which has emerged from organic chemistry, has undergone multiple trends and – depending on the indications – with various results. Many diseases have been eradicated, resulting in better quality of life and its elongation (e.g. analgesic, nontropic drugs). Other indications have arose and became unmet medical needs (e.g. neuropathic pain). Moreover, there are d...
To the average person, lithium-ion technology, at least until the last year or so, was represented by the black-box-like batteries in high-end consumer devices such as laptop computers. Mobile phone batteries use similar chemistry, although in that case the batteries are often lithium-polymer types that are frequently described as if they constitute an entirely different technology. The mystiqu...
Development of two new techniques for studying the gas phase chemistry of negative ions is reported. Collision induced dissociation (CID) of (M-1)- ions has been accomplished in a newly constructed triple stage quadrupole mass spectrometer. This instrument was assembled by adding two additional Finnigan quadrupole mass filters to a Finnigan Model 3200 CI mass spectrometer. Generation of (M-1)- ...
چکیده با کاهش ابعاد ترانزیستورهای ماسفت و نزدیک شدن به حد نانومتری، شیب زیر آستانه ترانزیستورها زیاد می¬شود. بالا بودن شیب زیر آستانه در این ترانزیستورها و داشتن نسبت ion/ioff پایین، کاربرد آنها را در مدارهای دیجیتال و آنالوگ دچار چالش می¬کند. برای کاهش شیب زیر آستانه و همچنین افزایش نسبت ion/ioff، ساختارهای تازه ای معرفی شده است که ترانزیستورهای اثر میدانی تونل زنی یکی از آنها است. این تران...
A reaction set of possible mineral weathering reactions is proposed to explain observed cation and silica export for the Emerald Lake watershed, a small Sierra Nevada, California catchment. The reaction set was calculated through a stoichiometric mole-balance method, using a multiyear record of stream flow and snowpack chemical analyses and site-specific mineral compositions. Reaction-set calcu...
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