1-(2,3-Dimeth­oxy­benzyl­idene)-2-(2,4-dinitro­phen­yl)hydrazine

In the title compound, C15H14N4O6, the dihedral angle between the aromatic rings is 3.7 (4)°. The nitro groups make dihedral angles of 6.0 (4) and 5.2 (4)° with the parent ring and are oriented at 6.0 (6)° with respect to each other. The meth­oxy groups are inclined at 54.0 (2) and 2.5 (3)° with respect to the benzene ring to which they are attached. In the crystal, mol­ecules are linked by weak C—H⋯O inter­actions. The mol­ecular conformation is consolidated by an intra­molecular N—H⋯O hydrogen bond

Purification and Concentration of the Total Saikosaponins Extracted from Radix Bupleuri using Foam Fractionation

Fundamental Research Funds for the Central Universities; Fujian Science and Technology Committee [2013H0043]; Xiamen Science and Technology Committee [3502Z20123005]The purpose of this study was to investigate the use of foam fractionation to recover saikosaponins. First, the solvent extraction method was applied for the extraction of saikosaponins from radix bupleuri using ethanol or deionized water. Then, the foam fractionation technique in batch mode was used for the recovery of the total saikosaponins from the extract. The effects of initial concentration, air flow rate, liquid loading volume, pH, and operating time on the process performance were investigated. The recovery percentage 77.2% and an enrichment ratio 3.68 of total saikosaponins with one-stage separation were obtained under the optimal conditions of initial saikosaponin concentration 0.18mg/mL, air flow rate 50mL/min, liquid loading volume 200mL, pH 5.5, and operating time of 2h. A two-stage foam fractionation technology was also designed, which was effective for improving both the recovery percentage and enrichment ratio simultaneously

Single and double over-barrier ionization of He, He

The classical over-barrier ionization model (COBI) method and trajectory calculations were utilized to simulate the ionization of He+ impacted by a positron. The calculated ionization cross sections of He+ agree with other theoretical data. Additionally, we found that the double ionization of He has a definite association with the positron-He+ impact. This result can explain why doubly ionized He seemed to be positron-scattered by the rest of the He+ in our previous study. The COBI model was also extended to study the double ionization caused by positron-Ne impacts. Our theoretical results agree with the experimental data