Novel Nano-composites SDC–LiNaSO4 as Functional Layer for ITSOFC

Nano-Micro Letters - As an ionic conductive functional layer of intermediate temperature solid oxide fuel cells (ITSOFC), samarium-doped ceria (SDC)–LiNaSO4 nano-composites were synthesized...     

全自动可调式翻页机构设计

设计一种能实现两个方向翻书动作的全自动可调式翻页机构,用于帮助有阅读障碍的人翻动书页,其主要通过单片机控制步进电机来完成各个翻书动作。重点介绍了该翻页机构的组成及控制方式,通过对各动作实现过程的研究分析,为实物的生产制作提供了方向。     

基于UGCAD模型的CMM自动测量路径规划

针对三坐标测量机床(CMM)对复杂曲面测量的特点,借助UG NX软件自身提供的平而截取功能和二次开发工具,对已知叶片的CAD模型,首先采用截平面法截取各档所需型线,然后通过系统的人机交互界面,将各档型线依次离散成点集,再运用本文提出的曲率差值淘汰算法进行点的筛选,保留一定数量的测量点,再提取出这些测量点的信息,最后再根...     

基于EMD复杂度特征和SVM的轴承故障诊断研究

针对滚动轴承振动信号的非平稳特性和在现实条件下难以获取大量故障样本的实际情况,提出一种经验模态分解、复杂度测量分析和支持向量机相结合的故障诊断方法.运用经验模态分解方法对其去噪信号进行分析,利用互相关系数准则对固有模式分量进行筛选,再计算所选分量的复杂度以组成故障特征向量,并将其作为支持向量机的输入以识别滚动轴承的故障...     

鳍片管代替光管省煤器及结构优化改造综述

在分析鳍片管束结构与传热特点的基础上,介绍了鳍片管代替光管省煤器的改造设计和应用情况。分析了鳍片管的直径、鳍片高度、厚度、管间距等参数及管束布置方式对省煤器传热特性、阻力特性、积灰和磨损等方面的影响。提出了鳍片管省煤器受热面优化设计的方法和步骤。     

Hydrogen-rich gas production from biomass air and oxygen/steam gasification in a downdraft gasifier

Biomass gasification is an important method to obtain renewable hydrogen. However, this technology still stagnates in a laboratory scale because of its high-energy consumption. In order to get maximum hydrogen yield and decrease energy consumption, this study applies a self-heated downdraft gasifier as the reactor and uses char as the catalyst to study the characteristics of hydrogen production from biomass gasification. Air and oxygen/steam are utilized as the gasifying agents. The experimental results indicate that compared to biomass air gasification, biomass oxygen/steam gasification improves hydrogen yield depending on the volume of downdraft gasifier, and also nearly doubles the heating value of fuel gas. The maximum lower heating value of fuel gas reaches 11.11 MJ/N m³ for biomass oxygen/steam gasification. Over the ranges of operating conditions examined, the maximum hydrogen yield reaches 45.16 g H₂/kg biomass. For biomass oxygen/steam gasification, the content of H₂ and CO reaches 63.27–72.56%, while the content of H₂ and CO gets to 52.19–63.31% for biomass air gasification. The ratio of H₂/CO for biomass oxygen/steam gasification reaches 0.70–0.90, which is lower than that of biomass air gasification, 1.06–1.27. The experimental and comparison results prove that biomass oxygen/steam gasification in a downdraft gasifier is an effective, relatively low energy consumption technology for hydrogen-rich gas production.     

耦合法在柴油机传热研究中的应用

利用流固耦合的分析方法,将柴油机气缸盖、气缸垫、气缸体、气缸套等柴油机主要零部件以及缸内气体、冷却介质作为一个耦合体,进行燃烧室部件的传热数值模拟实验。其中,冷却水侧的对流换热系数和温度由CFD软件Star-CD对整个水路进行模拟计算获得;底板火力面侧燃气的对流换热系数和温度由GT-POWER软件对缸内工作过程进行模拟获得;缸套燃气侧温度由活塞组——气缸套耦合传热模拟获得。最终的计算结果与实验数据较吻合,可以为柴油机热负荷分析和柴油机设计提供理论依据。     

4GE型汽油机三元催化转化试验研究

通过对采用闭环多点电控喷射系统并装用三元催化转化器的4GE型汽油机的试验证明,其排放值完全符合排放法规要求,对噪声影响不大,功率损失很小且对有害物的转化率很高,取得了满意的排放效果。     

Bibliometric trend analysis on global graphene research

Graphene is a rising star as one of the promising materials with many applications. Its global literature increased fast in recent years. In this work, bibliometric analysis and knowledge visualization technology were applied to evaluate global scientific production and developing trend of graphene research. The data were collected from 1991 to 2010 from the Science Citation Index database, Conference Proceeding Citation Index database and Derwent Innovation Index database integrated by Thomson Reuters. The published papers from different subjects, journals, authors, countries and keywords distributed in several aspects of research topics proved that graphene research increased rapidly over past 20 years and boosted in recent 5 years. The distinctions in knowledge map show that the clusters distributed regularly in keywords of applied patents in recent 5 years due to the potential applications of graphene research gradually found. The analytical results provided several key findings of bibliometrics trend.     

Generation of mesoporosity in MOR zeolites synthesized under perturbation conditions

The hydrothermal synthesis of various mesoporous materials with mordenite (MOR) structures is performed under perturbation conditions involving varying-temperature crystallizations and the use of ternary organic templates, and at least three types of mesoporous materials are obtained from the same starting gel containing the ternary organic templates. The greater structural diversities of these materials are found to correlate remarkably with the second-staged crystallization temperature and time. Among these materials, the two mesoporous materials crystallized incompletely over low temperature periods are differently structural composites consisting of MOR crystallites within disordered mesoporous phases, whereas the mesoporous mordenite crystallized completely over relatively high temperature period possesses the intrinsic microporosity and hierarchical mesoporosity. TEM morphological investigations on the mesoporous mordenite crystals demonstrate the formation of intracrystalline mesopores. Furthermore, an entirely new approach to synthesize mesoporous MOR zeolites is proposed based on the pore-inducing role of MOR structure defects and the adequate perturbation towards synthesis conditions.