三出口萃取工艺静态平衡研究

三出口萃取工艺是在普通分馏萃取工艺中间级增开一个出口使之同时分离三个组份。采用这一工艺可大大简化多元体系分离流程,提高经济效益。本文根据恒定总萃取比体系的本出口萃取工艺中各组份的静态物料平衡,推导出四种三出口萃取工艺的极值公式。通过计算机静态模拟计算确定了Gd/Tb/Dy三出口萃取工艺参数,并通过试验验证了计算结果。     

A partition identity on binomial coefficients and its applications

By means of formal power series technique, a binomial identity concerning two independent variables is presented which includes the most known partition identities as its very special cases.     

Dissectol A,A Novel Monoterpene Glycoside from Incarvillea dissectifoliola

Dissectol A,a novel monoterpene glycoside was isolated from the methanol part of the 95% EtOH extract of Incarvillea dissecfoliola and its structure was determined by 1D and 2D NMR data.     

Distributed feedback lasers: An overview

Distributed feedback (DFB) lasers were considered promising light-source candidates for coherent optical transmissions over a long-distance. In this paper, the development history of distributed feedback laser diodes (DFB-LDs) is briefly described, followed by a review of the theoretical analysis of DFB structures. Different DFB structures are investigated theoretically, with their performances compared in terms of threshold gain, spectral linewidth, stability, and external differential quantum efficiency. The analysis reveals the need for further improvement of DFB structures and further investigations into other characteristics of DFB-LDs before the DFB-LD can be used more efficiently for coherent optical transmissions.     

Crystal structures of 2,4-dimethylthioxanthene 10,10-dioxide, 2,4,9-trimethylthioxanthene 10,10-dioxide,and 2,4-dimethyl-9-isopropylthioxanthene 10,10-dioxide

The structures of 2,4-dimethylthioxanthene 10,10-dioxide, 1 , 2,4,9-trimethylthioxanthene 10,10-dioxide, 2 , and 2,4-dimethyl-9-isopropylthioxanthene 10,10-dioxide, 3 , have been determined by x-ray diffraction. The central ring of the thioxanthene ring system is in a boat conformation. The 9-methyl substituent in 2 and the 9-isopropyl substituent in 3 are both in the boat-axial conformation with respect to the central ring. The folding angles between the planes of the two benzo rings are 136.6°, 142.9°, and 134.3° for 1, 2 , and 3 , respectively.     

A new efficient decarboxylative reduction of γ-carbamoyloxy-α,β-unsaturated esters with lithium dialkylcuprate

A new synthetically useful decarboxylative reduction of γ-carbamoyloxy-α,β-unsaturated esters with lithium dialkylcuprate under mild condition was described.     

Particle simulation of a high-power gyrotron oscillator

A self consistent and time-dependent particle code has been developed to simulate the beam-wave dynamics in a gyrotron oscillator. The code is first applied to investigate the effect of the self-consistent field profile on the scaling of the cavity-filling rate with beam current. The fixed-field theory predicts that the transient-wave growth rate depends linearly on the beam current. The simulation results agree with the theoretical prediction at low beam currents. As the beam current increases, the modified field profile changes the nature of the gain scaling from linear to nonlinear. At higher beam currents, the excited wave is observed to exhibit the behavior of the modulated oscillation, due to unequal couplings to the forward- and backward-going waves by the beam. Associated with such amplitude modulation is a periodic variation of the self-consistent field profile. At still higher beam currents, the system becomes chaotic, showing the effect of periodic doubling. Simulation results are presented for the efficiency, the self-consistent field profile, and the scaling of the transient growth rate with the beam current