471 research outputs found
Evaluation on the Effects of Deicing Chemicals on Soil and Water Environment
AbstractDeicing chemicals are widely used to clear the pavement snow in the cold areas of China and many other countries in winter, because of their simple operation and excellent snow-melting effect, which leads to more convenience for traffic and low probability of traffic accident in the city, especially in metropolis. However, with the ever-growing application of deicing chemicals, their negative effects on environment such as soil and water system increased dramatically. Based on the related researches in China and abroad, this paper summarized the two categories of deicing chemicals and their working principles, and then provided the unique characteristics of deicing chemicalsâ effects on soil and water environment in large cities, which may need considerable quantity of the chemicals to relieve traffic congestion. What's more, main aspects of impacts by deicing chemicals on regional soil and water environment and the fundamental factors related to the aspects above respectively were generalized, in order to propose a conceptual model to evaluate the harmful effects. Moreover, this paper put forward some suggestions for the further research in this field to fulfill the model, and provided a scientific basis for the pollution prevention of deicing chemicals on urban environment
Mass measurements of neutron-deficient Y, Zr, and Nb isotopes and their impact on rp and Îœp nucleosynthesis processes
© 2018 The Authors. Published by Elsevier B.V. This manuscript is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence (CC BY-NC-ND 4.0). For further details please see: https://creativecommons.org/licenses/by-nc-nd/4.0/Using isochronous mass spectrometry at the experimental storage ring CSRe in Lanzhou, the masses of 82Zr and 84Nb were measured for the first time with an uncertainty of âŒ10 keV, and the masses of 79Y, 81Zr, and 83Nb were re-determined with a higher precision. The latter are significantly less bound than their literature values. Our new and accurate masses remove the irregularities of the mass surface in this region of the nuclear chart. Our results do not support the predicted island of pronounced low α separation energies for neutron-deficient Mo and Tc isotopes, making the formation of ZrâNb cycle in the rp-process unlikely. The new proton separation energy of 83Nb was determined to be 490(400) keV smaller than that in the Atomic Mass Evaluation 2012. This partly removes the overproduction of the p-nucleus 84Sr relative to the neutron-deficient molybdenum isotopes in the previous Îœp-process simulations.Peer reviewe
Direct Measurements of the Branching Fractions for and and Determinations of the Form Factors and
The absolute branching fractions for the decays and
are determined using singly
tagged sample from the data collected around 3.773 GeV with the
BES-II detector at the BEPC. In the system recoiling against the singly tagged
meson, events for and events for decays are observed. Those yield
the absolute branching fractions to be and . The
vector form factors are determined to be
and . The ratio of the two form
factors is measured to be .Comment: 6 pages, 5 figure
Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta
Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector,
the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are
measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and
(7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure
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