Molecular mechanical and quantum chemical methods were used to calculate the conformational and electronic structures of the template molecules of (nitro substituted an ill no)-4 - sub st nut ed -2, 6 -piperazinedione...Molecular mechanical and quantum chemical methods were used to calculate the conformational and electronic structures of the template molecules of (nitro substituted an ill no)-4 - sub st nut ed -2, 6 -piperazinediones, With the calculation results we explained the acylation reactivity of title compounds satisfactorily.展开更多
In order to measure differential cross sections of the 10B(n,α)7Li reaction induced by MeV neutrons using the forward-backward coincidence method, a thin film 10B sample was designed and the 10B atom number was deter...In order to measure differential cross sections of the 10B(n,α)7Li reaction induced by MeV neutrons using the forward-backward coincidence method, a thin film 10B sample was designed and the 10B atom number was determined with a reference 10B film sample. Alpha counts of the 10B(nth,α)7Li reaction from the 10B thin film and the reference sample were measured using a gridded ionization chamber and thermal neutrons, which were moderated and thermalized by paraffin from fast neutrons produced in D(d,n)3He reaction on a 4.5 MV Van de Graaff. The neutron flux was normalized by measuring the fission yield of a small 238U fission chamber.展开更多
The frequently used concept of "global reaction" is discussed and the reason for the confusion behind explained. The misconception is cleared by formula writing based on the donor–acceptor(donac) reaction c...The frequently used concept of "global reaction" is discussed and the reason for the confusion behind explained. The misconception is cleared by formula writing based on the donor–acceptor(donac) reaction concept and by applying the Grand Rule of Formula Writing that is based on it.展开更多
The atomic number densities of ^87 Rb vapor and surrounding gas 3He in a sealed cubic cell were measured by sweeping the absorption line and fitting the experimental data with a Lorentzian profile. The absorption was ...The atomic number densities of ^87 Rb vapor and surrounding gas 3He in a sealed cubic cell were measured by sweeping the absorption line and fitting the experimental data with a Lorentzian profile. The absorption was carried out around the D1 transition at different temperatures. We compare our results for the number density for^87 Rb with the previous methods and calculate the fractional error to be less than 5% as well as the error for ^3He between this work and the density obtained from the filling procedure to be no more than 4.2% at 370K. In addition, we discuss the factors that contribute to the error, among which the cell temperature plays the most important role.展开更多
On line determination of empirical formula for organic compounds with an automatic elemental analyzer and its program design method were investigated. The computational results shews that the reliability of computatio...On line determination of empirical formula for organic compounds with an automatic elemental analyzer and its program design method were investigated. The computational results shews that the reliability of computational results depends on the accuracy of the analytical data and the organic compound itself.展开更多
An empirical epuation to reveal relations between topological index(ZG)and physico chemical portes of normal paraffins is proposed as follows; p= a ig ZG/Nx + b, where P standsfor a physico-chemical property, N is the...An empirical epuation to reveal relations between topological index(ZG)and physico chemical portes of normal paraffins is proposed as follows; p= a ig ZG/Nx + b, where P standsfor a physico-chemical property, N is the number of carbon atoms in the molecule, and ZG is thetopological index proposed by Hosoya a, b, and x are constants related to a certain Phyaicochemical property. Thirteen properties are calculated ac this equation The values of theseproperties caiculated are Close to those from experiments.展开更多
文摘Molecular mechanical and quantum chemical methods were used to calculate the conformational and electronic structures of the template molecules of (nitro substituted an ill no)-4 - sub st nut ed -2, 6 -piperazinediones, With the calculation results we explained the acylation reactivity of title compounds satisfactorily.
基金Supported by National Natural Science Foundation of China (10575006 and 10811120014) and China Nuclear Data Center
文摘In order to measure differential cross sections of the 10B(n,α)7Li reaction induced by MeV neutrons using the forward-backward coincidence method, a thin film 10B sample was designed and the 10B atom number was determined with a reference 10B film sample. Alpha counts of the 10B(nth,α)7Li reaction from the 10B thin film and the reference sample were measured using a gridded ionization chamber and thermal neutrons, which were moderated and thermalized by paraffin from fast neutrons produced in D(d,n)3He reaction on a 4.5 MV Van de Graaff. The neutron flux was normalized by measuring the fission yield of a small 238U fission chamber.
文摘The frequently used concept of "global reaction" is discussed and the reason for the confusion behind explained. The misconception is cleared by formula writing based on the donor–acceptor(donac) reaction concept and by applying the Grand Rule of Formula Writing that is based on it.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61227902 and 61374210, the Shanghai Academy of Space Flight Technology, and the National High-Technology Research and Development Program of China.
文摘The atomic number densities of ^87 Rb vapor and surrounding gas 3He in a sealed cubic cell were measured by sweeping the absorption line and fitting the experimental data with a Lorentzian profile. The absorption was carried out around the D1 transition at different temperatures. We compare our results for the number density for^87 Rb with the previous methods and calculate the fractional error to be less than 5% as well as the error for ^3He between this work and the density obtained from the filling procedure to be no more than 4.2% at 370K. In addition, we discuss the factors that contribute to the error, among which the cell temperature plays the most important role.
文摘On line determination of empirical formula for organic compounds with an automatic elemental analyzer and its program design method were investigated. The computational results shews that the reliability of computational results depends on the accuracy of the analytical data and the organic compound itself.
文摘An empirical epuation to reveal relations between topological index(ZG)and physico chemical portes of normal paraffins is proposed as follows; p= a ig ZG/Nx + b, where P standsfor a physico-chemical property, N is the number of carbon atoms in the molecule, and ZG is thetopological index proposed by Hosoya a, b, and x are constants related to a certain Phyaicochemical property. Thirteen properties are calculated ac this equation The values of theseproperties caiculated are Close to those from experiments.
