嵌入式系统设计的新思路—SOC

90年代以来,SOC（Sytem On Chip)已成为微电子芯片技术发展的热点,SOC技术的出现表明了微电子技术由传统的IC（电路集成）向IS（系统集成）发展,它的出现拓展了嵌入式系统的设计思路,提高了设计的功能与效率。本文以便携式MP3播放器的设计为例,从一个方面展示了SOC技术的特点和优势。     

化工原理教学的探索与思考

化工原理是化学工程类专业的学科基础课,对学生从自然科学转到工程科学的学习上起到承上启下的作用。本文通过在与学生的互动中,对在化工原理课堂教学中的一些实践经验进行了归纳,以期更进一步促进课堂教学水平的提高。     

Performance of different fermentation methods and the effect of their duration on the quality of raw cocoa beans

This study aims to compare the effect of three cocoa fermentation methods and their duration on raw cocoa quality. Results showed a decrease in percentage of physical quality defects on fermentation method. Cocoa fermented for 4 days presented higher percentage of purple beans reached 45% and about 10% of slaty beans than cocoa fermented for 6 days whatever the process. Fermentation duration did not influence the mouldy beans that were around 1%. Formation of brown beans increased from 16% to 50% depending on the fermentation duration and process. Using wooden boxes allowed higher percentage of 77%–90% brown beans than others materials. Acidity of cocoa decreased on fermentation duration but beans treated in boxes were significantly (P = 0.05) acidic from 1.40 and 3.07 meq of NaOH g^?1. Fungal population did not vary in number depending both on the duration and the fermentation method with rates that ranged from 3.32 × 10⁷ to 8.63 × 10⁷ CFU g^?1.     

Safety assessment of dairy microorganisms: the Leuconostoc genus

Although Leuconostoc genus is "generally recognized as safe" (GRAS), a few clinically human infections cases by this microorganism have been reported in the literature, leading to their classification as opportunistic pathogens. However, these reported cases concern only severe immunodepressed patients, and none direct relations have yet been proven between Leuconostoc isolation and human diseases. Moreover, no cases of infections have been directly linked to the consumption of fermented food. Considering the long history of use of Leuconostoc in dairy industry, and their poor incidence in human infections cases, this bacterial genus may be reasonably considered as " safe " for its use in fermented dairy products.     

类金刚石薄膜的反应离子刻蚀

为了刻蚀出图形完整、侧壁陡直、失真度小、独立的类金刚石薄膜微器件,反应离子刻蚀是一种有效地刻蚀方法。研究了氧气与氩气的混合气体进行类金刚石薄膜刻蚀的主要工艺参数(刻蚀时间、有无掩膜、氩氧体积混合比、负偏压)。研究结果表明:在相同条件下,刻蚀速率随刻蚀时间变化不大;有无掩膜对刻蚀速率无明显影响;流量一定时,刻蚀速率随氩氧体积比的增大而降低,随负偏压的增大先增大后减小。实验得到最佳刻蚀条件,在此条件下,刻蚀出图形完整、侧壁陡直、失真度小的微器件,并成功制备出"独立"的微齿轮,进行了组装。     

siCp/Al复合材料的组织与断口分析

对国内外以铸造法制备的碳化硅颗粒增强铝(SiCp/Al)复合材料的组织与断口进行了观测和对比分析。低倍观测结果表明,在两种复合材料中碳化硅颗粒的分布都较均匀,无严重团聚现象。在高倍下发现碳化硅颗粒优先分布在晶界附近,形成“晶界花边”。SiCp/Al复合材料断口上肉眼可见的亮点可能是铸造孔洞的反映。      

编码器自动监测与故障诊断系统的研究与实现

文中介绍了某大型机电设备编码器的实时监测与故障诊断系统的设计工作.系统采用在线和离线两种工作方式,实现了接触式编码器的监测和诊断.系统硬件主要电路板基于PC104总线结构,18路I/O通道(9路输入,9路输出)完成9位编码器的检测和诊断.系统软件界面友好,巧妙地实现了格雷码与角度值的转换.本系统对其他编码器自动监测和故障诊断系统具有重要的借鉴意义.     

封隔技术在深井岩盐开采中的应用

文章拟通过封隔盐层技术、封隔器装置在蓬普一井的使用介绍,探索出深井岩盐井身结构与生产管串的有效合理配置.实现提高岩盐矿石采出率、保护中心管、延长卤井服务年限的途径,并对封隔技术在深井岩盐开采中应用后的效果进行了分析.     

浅析发展畜牧营养盐

通过分析畜牧业发展和其发展方向及畜牧营养盐的作用，论述了发展畜牧用盐的必要性和可行性，并结合实际情况，从生产企业及产品研发等角度提出了一些发展畜牧用盐的思路．供同行参考。     

基于NCP1200单端反激式多路输出开关电源设计

NCP1200开关电源专用芯片采用内部固定频率的脉宽调制电磁式,具有动态自供电系统,无需反馈绕组供电,内集成"跳过周期"模式和过流、过热保护功能.文中介绍了基于该芯片的小功率多路输出单端反激式开关电源的设计方案,并给出了注意事项及解决方案.试验结果表明,该电源电路结构简单,运行可靠,各路电源输出精度高.