多用途化学实验信息化教学平台建设

随着实验教学示范中心建设进程的推进,各级各类化学实验室均承担了多类别的教学任务,同时信息化技术在化学实验教学中的应用也日益普遍,多用途化学实验信息化教学平台成为了迫切需要。在这种形势下,华东理工大学化学实验教学中心开发了相应的信息化教学平台,区别于常见的虚拟化学实验系统,该平台淡化对多媒体技术手段的过分追求,注重贯彻实验前预习、实验中帮助、实验后测试的全过程跟踪的实验教学理念,尤其是实验操作过程中每一步操作的跟踪记录,强调对多类别教学任务的适应性。     

倾跌试验方法的优劣性分析

倾跌试验有多种方法,为了方便快捷地选取适用而有效的方法,本文就如何根据产品的不同外形、不同结构、不同电气性能选用适当的倾跌试验方法进行了具体分析。以便我们在工作中更准确更有效地选用。     

一种提高嵌入式系统UBI分区挂载速度的设计方案与研究

根据Linux嵌入式系统UBI分区的挂载原理,在系统关机时预先扫描UBI设备中PEB块的相关头信息,并进行相关压缩处理后存储在UBI分区中的指定物理位置,使得系统下次开机时内核可直接读取预先存储的扫描信息,节省了大量时间.以关机时间换取开机速度的提高,在大量使用UBIFS的基于NAND flash嵌入式系统应用中有很好的优势.     

灰乳的陈化

<正> 明胶生产要用石灰乳浸泡处理骨素。那么,石灰乳应该如何配制才能充分得到利用,这是笔者关注的一个问题。为此我们做了下面的实验。     

Fe_2O_3-Sb_2O_4复合氧化物催化剂的催化活性组分及其在丙烯氨氧化中的作用

为了阐明Fe_2O_3-Sb_2O_4复合氧化物催化剂在丙烯氨氧化中的催化性能,我们采用X线衍射、穆斯堡尔谱和XPS对有、无载体的不同锑铁比和焙烧温度的一系列催化剂进行了研究.X线衍射测定表明,这些样品中都有FeSbO_4,并且a-Fe_2O_3或Sb_2O_4的出现与Sb/Fe有关.催化剂的穆斯堡尔谱都有一对由FeSbO_4中顺磁Fe~(3+)引起的双峰;只有在Sb/Fe<1时,才有a-Fe_2O_3的典型六线谱出现.经800℃焙烧的Sb/Fe>1催化剂还都展现出由FeSb_2O_6中Fe~(2+)引起的另一对双峰.根据对富锑催化剂的XPS分析,结合能为709.3电子伏特的肩峰的出现,又进一步证明这种含Fe~(2+)的新活性组分FeSb_2O_6的存在.丙烯转化速度与Fe~(3+)/Fe~(2+)的关系表明,催化剂的催化性能不只取决于一种活性组分.以丙烯腈的生成速度与Fe~(3+)和Fe~(2+)的浓度关系可以得出结沦:FeSbO_4是基本活性组分,而在其上生成含Fe~(2+)新相则可能是使催化剂具有选择氧化作用的原因.     

掺银对TIBaCaCuO系超导体性能的影响

本文研究了掺入适量的银对TlBaCaCuO系超导体超导性能的影响。实验结果表明,当银的掺入量不超过0.3mol时,有利于2223相的形成;在掺入0.3mol银的同时,适当提高组成中Tl或Cu的含量,可以降低烧结温度,并能获得T_(o0)=122K,T_(onset)=136K的TlBaCaCuO系超导体。     

Reproducibility and stability of N–Al codoped p-type ZnO thin films

Reproducible and stable p-type ZnO thin films have been prepared by the N–Al codoping method. Secondary ion mass spectroscopy measurements demonstrate that N and Al are incorporated into ZnO. The resistivity, carrier concentration, and Hall mobility are typically of 50–100 Ωcm, 1×10¹⁷–8×10¹⁷ cm⁻³, and 0.1–0.6 cm²/Vs, respectively, for the N–Al codoped p-type ZnO films. Hall measurement, X-ray diffraction, and optical transmission were carried out to investigate the changes of the properties with the storage period. Results show that the p-type characteristics of the N–Al codoped ZnO films are of acceptable reproducibility and stability. In addition, the N–Al codoped p-type ZnO films have good crystallinity and optical quality. The properties are time independent.     

Research and Improvement on structure stability and corrosion resistance of nickel-base superalloy INCONEL alloy 740

INCONEL alloy 740 is a newly developed Ni–Cr–Co–Mo–Nb–Ti–Al superalloy in the application to ultra-supercritical boilers with steam temperatures up to 700 °C. By means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), micro-chemical phase analyses, and corrosion-resisting test, this paper investigates the structure stability of the alloy at elevated temperature and concentrates on coal ash corrosion performance of the alloy under the simulated coal ash/flue gas condition. Experimental results show that the most important structure instabilities of the alloy during prolonged aging are γ′ coarsening, γ′ to η transformation and G phase formation at grain boundary. The performance of corrosion resistance of the alloy would meet the requirement of ultra-supercritical boiler tubes. The phase computation by means of Thermo-Calc has been adopted in chemical composition modification for structure stability improvement. Two suggested new modified alloys in adjustment of the Al and Ti contents and in control of Si level, and also in maintenance of Cr content of the alloy were designed and melted for experimental investigation. These two modified alloys exhibit more stable microstructure during 760 °C long time aging.     

Determination of density distribution in ferrous powder compacts using ultrasonic tomography.

Laser-induced ultrasonic bulk wave tomography is used for density variation determination of powder metal compacts. A laser beam is used to excite ultrasonic energy, and the signals passing through the specimen are received by an air-coupled transducer. The density variations of powder metal compacts can be determined directly by the cross-sectional tomographic images of slowness obtained by using a filtered, backprojection algorithm based on measured time of flights. Interpolations with respect to sample and projection angles are used to generate the input data required for displaying a well-balanced, reconstructed image to reduce the aliasing distortions caused by insufficient input data. Results of presintered cylindrical ferrous powdered samples show that this novel approach makes the reconstruction process more cost effective than the very tedious, time-consuming, and inaccurate metallographic methods, thus making it a potentially powerful tool for studying manufacturing processes through significant parameters to obtain a more uniform density distribution.