摘要：The hydrogenation of CO_(2) into methanol has attracted much attention and In_(2)O_(3) is a promising *** metal elements into In_(2)O_(3)(M/In_(2)O_(3))is one of the main strategies to improve its ***,its mechanism and active sites remain unclear and need to be further ***,the noble‐metal‐free In_(x)‐Co_(y) oxides catalysts were ***‐improved performance and obvious product selectivity shift were *** optimized catalyst(In_(1)‐Co_(4))(9.7 mmol g_(cat)^(–1) h^(–1))showed five times methanol yields than pure In_(2)O_(3)(2.2 mmol g_(cat)^(–1) h^(–1))(P=4.0 MPa,T=300°C,GHSV=24000 cm^(3)_(STP) g_(cat)^(–1) h^(–1),H_(2):CO_(2)=3).And the cobalt‐catalyzed CO_(2) methanation activity was suppressed,although cobalt was most of the metal *** unravel this selectivity shift,detailed catalysts performance evaluation,together with several in‐situ and ex‐situ characterizations,were employed on cobalt and In‐Co for comparative *** results indicated CO_(2) hydrogenation on cobalt and In‐Co catalyst both followed the formate pathway,and In‐Co reconstructed and generated a surface In_(2)O_(3)‐enriched core‐shell‐like structure under a reductive *** enriched In_(2)O_(3) at the surface significantly enhanced CO_(2) adsorption capacity and well stabilized the intermediates of CO_(2) ***_(2) and carbon‐containing intermediates adsorbed much stronger on In‐Co than cobalt led to a feasible surface C/H ratio,thus allowing the*CH_(3)O to desorb to produce CH_(3)OH instead of being over‐hydrogenated to CH_(4).

摘要：人类向大气中排放的大量二氧化碳(CO_(2))造成了一系列环境问题,极大地威胁了人类的生存。CO_(2)催化加氢在众多CO_(2)减排思路中具有独特优势。将CO_(2)与氢气(H_(2))转化为高附加值的下游化学品,既可以减少大气中CO_(2)浓度,又可以生产具有经济价值的商品,具有良好的应用前景。近年来,氧化铟(In_(2)O_(3))催化剂作为一种高效的新型CO_(2)加氢制甲醇的催化剂在学界饱受关注。In_(2)O_(3)表面经过活化后会产生大量氧空位,氧空位周期性产生和湮灭组成的机制抑制了副反应的发生,将CO_(2)高选择性地加氢转化为甲醇。文献中报道In_(2)O_(3)在200~300℃时甲醇选择性接近100%,特别是在高温下仍能维持高甲醇选择性。这种高温下优异的性能使In_(2)O_(3)可被用于与沸石分子筛耦合制备催化CO_(2)加氢直接制烃类化合物的双功能催化剂。In_(2)O_(3)催化剂的缺陷在于其CO_(2)的转化率较低限制了甲醇的产率。学界目前采取了一系列策略对In_(2)O_(3)催化剂进行优化和改进。主要的策略有二:(1)将In_(2)O_(3)负载在其他氧化物载体上;(2)在In_(2)O_(3)体系中引入其他金属元素。将In_(2)O_(3)负载在其他氧化物载体上可以增加In_(2)O_(3)的分散度,增加催化剂中氧空位的含量,增强吸附CO_(2)的能力,稳定关键的表面中间物种。将In_(2)O_(3)负载在ZrO_(2)上是该策略的典型例子,它可以极大地增强催化剂的本征活性。在In_(2)O_(3)体系中引入其他金属元素可以增强H_(2)解离吸附以及H_(2)溢流的能力。文献中已经报道了在In_(2)O_(3)体系中引入Pd、Pt、Cu、Rh、Au、Co、Ni等金属,并取得了良好的效果。本文归纳了In_(2)O_(3)催化剂用于CO_(2)加氢的研究进展,分别对In_(2)O_(3)的结构、In_(2)O_(3)用于CO_(2)加氢的现状、以及新型In_(2)O_(3)基催化剂的设计与改良三个方面对In_(2)O_(3)在CO_(2)加氢中的应用进行综述,并对In_(2)O_(3)基催化剂用于CO_(2)加氢反应的研究思路以及发展前景进行展望,以期为之后In_(2)O_(3)催化体系用于CO_(2)加氢的研究提供思路及参考。

摘要：活塞环内外圆轮廓是一种不规则的自由型线,切削加工困难,通常所用的仿形靠模车床存在加工效率低、调整周期长、靠模易于磨损等缺陷。在分析活塞环切削加工特点的基础上,应用直线伺服电动机研制开发了一台高速响应活塞环数控车床,并对该机床研制中的关键技术,如活塞环开口过渡曲线拟合、快速响应刀具进给系统研制、机床总体结构设计、活塞环CAD/CAM软件模块开发等进行了阐述。

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摘要：报道了一种新近研究开发的面向ＣＩＭ 新型组合机床ＣＡＤ 系统． 该系统基于产品装配模型进行开发，采用了面向对象的软件开发技术，支持自上而下的设计过程，提供了与下游生产活动的产品数据接口，可以方便与下游生产活动的集成．