Изменение диэлектрических потерь резин на основе этилен-пропиленовых каучуков со временем ионизационного старения

В работе изучалось влияние вулканизующей группы и наполнителя на диэлектрические потери резин на основе этилен-пропиленовых каучуков и изменение диэлектрических потерь со временем ионизационного старения. Установлено, что диэлектрические потери и изменения их со временем ионизационного старения в значительной степени зависят от типа вулканизующей группы и наполнителя

Adsorption separation of heavier isotope gases in subnanometer carbon pores

Isotopes of heavier gases including carbon (13C/14C), nitrogen (13N), and oxygen (18O) are highly important because they can be substituted for naturally occurring atoms without significantly perturbing the biochemical properties of the radiolabelled parent molecules. These labelled molecules are employed in clinical radiopharmaceuticals, in studies of brain disease and as imaging probes for advanced medical imaging techniques such as positron-emission tomography (PET). Established distillation-based isotope gas separation methods have a separation factor (S) below 1.05 and incur very high operating costs due to high energy consumption and long processing times, highlighting the need for new separation technologies. Here, we show a rapid and highly selective adsorption-based separation of 18O2 from 16O2 with S above 60 using nanoporous adsorbents operating near the boiling point of methane (112 K), which is accessible through cryogenic liquefied-natural-gas technology. A collective-nuclear-quantum effect difference between the ordered 18O2 and 16O2 molecular assemblies confined in subnanometer pores can explain the observed equilibrium separation and is applicable to other isotopic gases

Hybrid effects in graphene oxide/carbon nanotube-supported Layered Double Hydroxides: Enhancing the CO₂ sorption properties

Graphene oxide (GO) and multi-walled carbon nanotubes (MWCNT) have been previously used independently as active supports for Layered Double Hydroxides (LDH), and found to enhance the intrinsic CO₂ sorption capacity of the adsorbents. However, the long-term stability of the materials subjected to temperature-swing adsorption (TSA) cycles still requires improvement. In this contribution, GO and MWCNT are hybridized to produce mixed substrates with improved surface area and compatibility for the deposition of LDH platelets, compared to either phase alone. The incorporation of a robust and thoroughly hybridized carbon network considerably enhances the thermal stability of activated, promoted LDH over twenty cycles of gas adsorption-desorption (96% of retention of the initial sorption capacity at the 20th cycle), dramatically reducing the sintering previously observed when either GO or MWCNT were added separately. Detailed characterization of the morphology of the supported LDH, at several stages of the multicycle adsorption process, shows that the initial morphology of the adsorbents is more strongly retained when supported on the robust hybrid GO/MWCNT network; the CO₂ adsorption performance correlates closely with the specific surface area of the adsorbents, with both maximized at small loadings of a 1:1 ratio of GO:MWCNT substrate

CHARACTERIZATION OF POLYCRYSTALLINE SILICON PARTICLES PRODUCED VIA CVD FROM MONOSILANE IN A FLUIDIZED BED REACTOR

Characterization of polycrystalline silicon particles produced in a fluidized bed reactor via CVD from monosilane was carried out. It was observed that part of the hydrogen from monosilane remained in the particles. Most of hydrogen was bonded to silicon and temperatures as high as 1300 K were required to dehydrogenate the silicon particles. Particles were contaminated with metal elements which were diffused from the reactor wall, suggesting that the material used in constructing the fluidized bed reactor wall also needed to be controlled to improve the purity of product

DEVELOPMENT OF A PLASMA JETTING FLUIDIZED BED REACTOR

A plasma jetting fluidized bed reactor was developed for coating particles via PCVD. Conversion of methane was carried out to investigate characteristics of this type of reactor. It was found that introduction of reactive gases from the side of a d.c. plasma jet resulted in no deterioration of the stability of plasma and that the reactive gases were effectively activated even in the presence of particles. Particles packed in the reactor promoted reactions to give carbon in the presence of hydrogen in a large excess, strongly suggesting that PCVD on fluidized particles can be realized