异佛尔酮催化异构化的精馏工艺研究

以α-异佛尔酮为原料,催化异构化制备β-异佛尔酮。研究了精馏柱类型、塔顶温度、催化剂、催化剂用量及回流比对产品纯度的影响。在1.5 m不锈钢θ环填充柱,回流比为20,塔顶温度为120℃条件下,β-异佛尔酮纯度为96.5%。     

精馏—冷却结晶法分离薄荷油的研究

本文通过精馏方法对天然薄荷油进行一次分离、试验证明分离效果良好，一次分离后的薄荷油经冷却结晶后得到的晶体能够达到很高的纯度及较高的产量。     

醋酸生产精馏装置改造的研究

吉化电石厂的醋酸生产目前仍采用乙醛氧化法制取醋酸的工艺技术，精馏工艺采用的流程为高低高的双塔精馏方式。鉴于此，本研究采用的工艺为单塔精馏，减小物料在精馏过程中的停留时间，以达到节能，省时，减少费用的目的，避免双塔精馏所造成的设备与能源的浪费。     

三相整流电路有源功率因数校正技术

介绍并归纳总结了三相整流电路有源功率因数校正技术的研究现状及各种三相有源功率因数校正电路的优缺点。在此基础上，指出了其发展趋势。     

Single-step electrochemical functionalization of double-walled carbon nanotube (DWCNT) membranes and the demonstration of ionic rectification

Carbon nanotube (CNT) membranes allow the mimicking of natural ion channels for applications in drug delivery and chemical separation. Double-walled carbon nanotube membranes were simply functionalized with dye in a single step instead of the previous two-step functionalization. Non-faradic electrochemical impedance spectra indicated that the functionalized gatekeeper by single-step modification can be actuated to mimic the protein channel under bias. This functional chemistry was proven by a highly efficient ion rectification, wherein the highest experimental rectification factor of ferricyanide was up to 14.4. One-step functionalization by electrooxidation of amine provides a simple and promising functionalization chemistry for the application of CNT membranes.     

Negative differential resistance,rectifying performance and switching behaviour in carbon-chain based molecular devices

Using non equilibrium Green's function formalism coupled with density functional theory, we carry out electronic transport calculation in two types of molecular devices, one constructed by linear monoatomic carbon chain (···C–C–C–C ···) and the other by two carbon chains capped with a phenyl ring (···C–C–Ph–C–C···), sandwiched between two z-shape electrodes, constructed by zigzag-armchair-zigzag (zz-ac-zz) graphene nanoribbons (GNRs). The potential difference between the z-shape contacts can be varied by employing an external d.c. voltage source. Thus, one may observe the variation of conductivity through the channels. The current–voltage (I–V) characteristics of the proposed resistors show N-type negative differential resistance (NDR), within a particular voltage region. The figure of merit or PVR (peak to valley) ratio (I_peak/I_valley) gets significantly increased, on capping the chains with phenyl ring. A higher value of PVR in I–V characteristics enhances the possibility of applications utilizing NDR. The calculated I–V characteristic is asymmetric and the rectification ratio is found to be 7, in case of the linear carbon chain.The rectification ratio R(V) = I(V)/I(−V) is an important parameter which determines, its suitability as rectifying device. It has been demonstrated that on varying the conformation of the phenyl ring with respect to the plane of electrodes, the transport properties of the system can be modulated. Interestingly, I–V characteristics are asymmetric and show dual NDR peaks in perpendicular conformation of the phenyl ring, with respect to the electrodes in the (···C–C–Ph–C–C···) system. The figure of merit is found to be respectively 8 and 51 for the first and second NDR regions. The later value is extremely high, making it an excellent candidate for potential applications. Moreover, the multi peak NDR device may be widely used in multiple-valued logics. Only a limited number of multiple NDR peak molecular-based nano systems have so far been reported, which are quite complex; by contrast the present system seems to be quite simple. The physical phenomenon of NDR was explained in the light of molecular projected self-consistent Hamiltonian (MPSH) and also the evolution of the frontier molecular orbitals (HOMO–LUMO) as well as transmission under various external bias voltages.     

大调压范围的单器身十二脉波整流系统设计

介绍了单器身12脉波整流系统在阀侧电压调压范围大、D接和Y接电压差比较大时,整流系统的触发方案,并通过仿真验证了方案的可行性。     

闪变仪中调制波的几种检波方法

本文分析比较了闪变仪中常用的几种检波方法，为四变仪的进一步研制提供了参考。     

精馏操作型问题分析求解

本文论述了板式二元摘馏塔操作型问题分析求解所依据的关系式，并通过对几种常见的典型的操作型问题分析，阐述了这类问题求解方法     

可控整流电路晶闸管两端电压波形计算机仿真

该文将介绍几种常用可控整流电路晶闸管两端承受电压波形的数字计算机仿真。用Ｃ语言编制仿真软件，仿真图形清晰，使用方便，有实用价值。