Synthesis, isolation, spectroscopic and electrochemical characterization of some calcium-containing metallofullerenes

A few Ca-containing mono-metallofullerenes, i.e. Ca@C₇₆, Ca@C₈₈, Ca@C₉₀ (I, II), were synthesized by an improved DC arc discharge method and isolated by a multi-stage HPLC method for the first time. These isomer-separated metallofullerenes were characterized by LD-TOF MS and UV-vis-NIR spectrometry. Their HOMO-LUMO band gaps and possible molecular geometries are discussed according to the absorption spectra in this report. In addition, the cyclic and differential pulse voltammetry of Ca@C₇₆ was conducted in MeCN/C₆H₅CH₃ (1:4 v/v). The voltammograms of Ca@C₈₂ (II, III) and Ca@C₈₄ (II) were also recorded. Their electrochemical behaviors are discussed compared with those of corresponding ytterbium metallofullerenes. The features of the Ca metallofullerenes’ electronic structures are also discussed.     

Studies of structure and cycleability of LiMn2O4 and LiNd0.01Mn1.99O4 as cathode for Li-ion batteries

Lithium manganese oxides LiMn₂O₄ and rare earth elements doped LiNd_0.01Mn_1.99O₄ were synthesized by microwave method. The structure and the electrochemical performances of the samples were characterized. XRD data shows both samples exhibit the same pure spinel phase. But due to the introduction of Nd³⁺ ion into the unit cell, the lattice parameter of the Nd-doped spinel was larger than that of the undoped one. The two samples had a similar morphology including small particle size and homogeneous particle distribution as tested by SEM. The cyclic voltammmetry and constant-current charge-discharge tested that Nd-doped spinel displayed a better reversibility and cycleability.     

浅谈构建安全的长江海事电子政务网络体系

电子政务已成为长江海事局工作信息化的重点工程。对长江海事电子政务网络建设的基础安全服务设施、安全管理保障体系、安全技术支撑平台和响应与恢复机制等问题进行了分析,并结合实践经验,提出了建立安全可靠的长江海事电子政务网络体系的对策。     

Possible Energy Network with polygeneration system and CCS for China

On basis of adopting polygeneration systems for power and alternative fuels,capturing CO2 with near zero energy penalties,and storing CO2 on sites,a new kind of Energy Network can integrate energy utilization,CO2 capture,transportation and storage synthetically.Techno-economic analysis of this solution focusing on Inner Mongolia and the Yangtze River Delta districts had been carried with comparison to the chain method for energy utilization and CO2 sequestration.This solution can save 21.5% of energy,and re...     

提高MG2×150/700-WD型采煤机截割部轴承寿命周期的设计改进

通过改进结构及轴承类型,提高MG2×150/700-WD型交流电牵引采煤机截割部轴承使用周期。     

我国电子签名法所面临的问题及对策研究

《中华人民共和国电子签名法》是我国信息化领域的第一部法律。本文阐述了《电子签名法》的主要内容,分析了它在当今信息化产业中的重要作用以及存在的不足,并且对其应采取的对策进行了探究。     

工程咨询在低碳经济发展中要有所作为

一、低碳经济将成为未来经济发展方向 所谓低碳经济是指以低能耗、低物耗、低排放、低污染为特征的绿色经济发展模式。它要求以最少的温室气体排放获得最大的经济产出。是人类社会继农业文明、工业文明之后的又一次重大进步,是生态文明建设的内在要求。     

Progress and recent trend in MILD combustion

Moderate or intense low oxygen dilution(MILD)combustion plays a significant role in the mitigation of combustion-generated pollutants and greenhouse gases whilst meeting thermal efficiency needs.However,due to the lack of the fundamental knowledge on this combustion,there is a misconception that MILD combustion should be established by high preheating of the air,which has limited its application.Our research and development on this combustion has been performed for several years. We have found that the requ...     

Liquid-liquid separations in a conventional hydrocyclone

The performance of a conventional hydrocyclone for separation of immiscible liquids was investigated experimentally. The results are particularly useful for evaluation of multi-cyclone process design of same system. The effect of materials of constructions of the hydrocyclone on the separation efficiency was also tested. Significant differences in performance were noted depending on the preferential wettability characteristics of the solid surfaces for the liquids being separated.     

Tungsten Oxide Nanorods Array and Nanobundle Prepared by Using Chemical Vapor Deposition Technique

Tungsten oxide (WO₃) nanorods array prepared using chemical vapor deposition techniques was studied. The influence of oxygen gas concentration on the nanoscale tungsten oxide structure was observed; it was responsible for the stoichiometric and morphology variation from nanoscale particle to nanorods array. Experimental results also indicated that the deposition temperature was highly related to the morphology; the chemical structure, however, was stable. The evolution of the crystalline structure and surface morphology was analyzed by scanning electron microscopy, Raman spectra and X-ray diffraction approaches. The stoichiometric variation was indicated by energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy.