Synthesis and characterization of La2Ti2O7 employed for photocatalytic degradation of reactive red 22 dyestuff in aqueous solution

Perovskite structured La₂Ti₂O₇ catalyst prepared by polymerized complex method was characterized and examined the photocatalytic activity by decomposing an azo dyestuff, Reactive Red 22, in aqueous solutions under UV irradiation. La₂Ti₂O₇ powders prepared by polymerized complex method exhibit higher surface areas, better homogeneity and are more sensitive to solution than those prepared by solid-state method. The first derivatives of UV–vis DRS patterns confirmed the complete crystallization of La₂Ti₂O₇ sintered at temperatures higher than 900 °C. The effects of sintering temperature of catalyst and solution pH of photocatalytic reaction were studied. The photocatalytic decomposition of Reactive Red 22 per unit surface area was found to be higher for experiments using La₂Ti₂O₇ than using TiO₂. However, the electron–hole recombination was found to be more obvious for La₂Ti₂O₇ than for TiO₂ because the network of metal cations constructed within La₂Ti₂O₇ enhances the mobility of photogenerated electrons and holes.     

Progress in Thermal Contact Resistance

The developments of aeronautics and astronautics require engines of higher quality. The temperature distribution in combustion engine is highly influenced by the thermal conduct resistance. To predict the temperature field of the hot-end assemblies of combustion engine, the thermal contact resistance must be considered. The object of the study is to propose a model of high application including in conditions of high temperature and high pressure. Up to date, many models and empirical or semi-empirical corre...     

300 MW机组直接空冷系统凝结水过冷却分析

以包头市第二热电厂300 MW直接空冷系统为例,分析了凝结水过冷却的原因,主要有凝结水回水被外界空气冷却、真空严密性差以及补充水溶氧和补水方式的影响等,提出加装保温、雾化喷嘴和改进补水方式等减小冷却度的措施.     

分相无功补偿装置的研制

为了改善电能质量,研制了一种新型无功补偿装置(SVC),对三相不对称负载的无功功率进行分相补偿,使得电网的无功功率得到大致的平衡。该装置的控制器使用新型ATmega16单片机进行控制,运用了傅里叶快速分解和瞬时无功功率理论[1],采用晶闸管作为开关,循环投切电力电容器组,实现无功补偿,本文对该型无功补偿装置的软硬件基本原理进行了介绍。通过样机运行表明,该装置控制准确灵活、补偿方式安全、效果明显,具有较大的社会效益与经济效益。     

磨料和H_2O_2对InSb CMP效果影响的研究

InSb由于硬度低、脆性大等特性,其材料表面的精密加工水平成为制约器件性能进一步提高的重要因素.采用化学机械抛光(CMP)技术对InSb进行表面加工,分析了CMP过程中抛光液的磨料质量分数和氧化剂含量对InSb的CMP效果的影响规律,实验研究了磨料和氧化剂(H2O2)的优化配比参数,并在此参数下,获得了良好的抛光表面.     

彩色图像与灰度图像间转换的程序设计

图像处理是一门很有价值的学科,在科学技术不断发展的今天它的技术已趋于成熟.同时图像之间的转换,在实际应用中也显的越来越重要.本文主要介绍彩色图像的灰度转换和伪彩色处理算法.并且利用这两种算法设计出两种图像转换的程序.论文对程序的主要结构进行了说明,列出了程序的流程图.并且对彩色图像和灰度图像的一些基本属性进行了介绍.     

校园CPU卡密钥管理系统的设计与实现

文章研究了密钥管理系统在校园一卡通系统中的应用模式。首先以CPU卡技术和密码算法技术为基础,提出了一卡通系统的密钥管理系统的解决方案;然后针对系统的实现,描述了密钥分散的设计和实现过程;最后对系统中使用的算法进行了描述。密钥管理系统保证了高强度的校园一卡通系统的安全性。