Molecular dynamics studies on octadecylammonium chloride at the air/liquid interface

Molecular dynamics simulations on surfactant octadecylammonium chloride at the air/liquid interface were performed. It was found that the alkyl chains of octadecylammonium would change to order with increasing the concentration of octadecylammonium at the air/liquid interface. Some functions, such as the concentration distributions, the radial distribution function and the mean squared displacement (MSD) were evaluated to investigate the structural properties of interface. We found that the salts can affect octadecylammonium aggregate at the interface: (1) univalent ions, such as chloride and sodium ions, affect slightly the structure of monolayer and (2) bivalent ions, such as sulfate or calcium ions, affect greatly, especially for the bivalent negative ions.     

贮氢材料电极循环寿命的定量预测定时放电半衰期法的应用

贮氢材料电极循环寿命的定量预测定时放电半衰期法的应用韩剑文，袁满雪，周作祥，赖城明（南开大学化学系天津３０００７１）关键词：贮氢电极，循环寿命，半衰期。前文￣［１］讨论了应用定终点电位放电半衰期法来预测贮氢材料电极循环寿命的问题。本文讨论如何采用定时...     

Exposure dose assessment and discussion on radioisotope production and application

The exposure dose status on radioisotope production and application in China has been assessed in the paper. The average annual occupational exposure dose received by workers in the radioisotope production is about one tenth of the annual dose limit in normal situation. It is less than one twentieth for workers in the radioisotope applications. However, the annual collective dose for the latter is higher than the former by one oder of magnitude due to the larger number of workers in the application field. Although the output of radioisotopes increased doubly in 1980's as compared with 1970's, the increase on the annual collective dose was not obvious. For exposure to the public,¹³¹I for example, the collective dose in the radioisotope production decreased by one to two orders of magnitude and the releasing factor reduced by two orders of magnitude. Therefore, the exposure dose received by workers in radioisotope production and application is lower in normal situation. However, the facts worth paying attention to are that there were many events and accidents which happened in the radioisotope applications, especially at the irradiation facilities. The probability of fatal accident was as high as 10^–3 per irradiator year. In order to improve the radiation safety situation, it is imperative to conduct the safety assessment for irradiation facilities, to enhance management of the radioactive wastes and spent sources and to establish the experience feedback system.     

On the Sixth Power Mean of the Two-term Exponential Sums

Acta Mathematica Sinica, English Series - The main purpose of this article is to study the calculating problem of the sixth power mean of the two-term exponential sums, and give an interesting...     

Observation of isomeric states in197Bi

The high spin states of¹¹⁹Te, populated in¹¹⁰Pd(¹³C,4n) and¹¹⁰Pd(¹²C,3n) reactions, have been studied through -ray spectroscopy. The level scheme has been established upto a spin of 55/2. Three-quasiparticle states, based on g² _7/2h_11/2 and g_7/2d_5/2h_11/2 configurations, have been identified. The 35/2 and 39/2 states are suggested to be the fully aligned states constituted by five valence h_11/2 ³, g_7/2, d_5/2 quasiparticles.