自主存储式水力压裂过程井下测试系统设计

水力压裂过程的井下测试是压裂效果评价、改进压裂工艺的重要依据.在进行井下测试时,由于实际作业时间常与计划时间有较大差异,经常造成预先按作业计划设定存储的且存储容量有限的井下测试仪对关键时段没有记录.论文中分析了压裂作业井下压力曲线在不同作业时段的特征,提出了以压力、压力梯度作为特征参数来判定压裂作业所处时段的简单逻辑判别方法,并设计了自主存储策略和基于单片机的仪器电路.测试实验表明该方法是有效的,仪器可自主对关键时段的参数进行密集采样和存储.     

Construction of an autonomously replicating plasmid in n-alkane-assimilating yeast, Candida tropicalis

A transformation system using the autonomously replicating plasmid in the n-alkane-assimilating and asporogenic diploid yeast, Candida tropicalis, was developed. For the cloning of a DNA fragment containing a potential autonomously replicating sequence (ARS) from the genomic DNA of C. tropicalis, the ura3 mutant obtained using ethylmethane sulfonate as the host and the URA3 gene amplified by PCR using the C. tropicalis genomic DNA as a selectable marker were prepared. Comparison of ARSs among yeasts revealed that the consensus sequence found in S. cerevisiae was also present in C. tropicalis. The autonomously replicating plasmid containing the putative ARS as the shuttle vector, capable of replicating in both E. coli and C. tropicalis, was first constructed. The transformation system using this plasmid, in addition to the integrative transformation system, will be applicable to genetic studies of C. tropicalis.     

地下铲运机自主行驶过程中转向死区的研究

地下铲运机依靠车载控制器输出的指令控制行驶方向,实现自主行驶。虽然控制器输出是线性的,但是地下铲运机动作却不是,当输出值过小,地下铲运机不转向,存在转向死区现象。对此开展研究,通过对死区的理论分析,试验测试,优化地下铲运机的控制算法,进而减小地下铲运机在行驶过程中死区的影响,提升自主行驶的控制效果。     

Trinocular vision for AGV guidance: Path localization and obstacle detection

This paper presents an integrated approach to the problem of AGV guidance using trinocular vision. Although this method uses three cameras, we will not do any processings related to stereo matching nor 3-D reconstruction. Instead, our trinocular vision is divided into two subsystems: monocular vision for path localization and binocular vision for obstacle detection. First, we demonstrate the geometric principle of 2-D vision. Then, we show its application for the task of AGV's path localization as well as the task of AGV's obstacle detection in the framework of trinocular vision. Experimental results with real images prove the usefulness of our method.     

基于磁耦合谐振的自主无线充电机器人系统设计

设计了具有非接触自主无线充电功能的室内移动机器人系统,采用基于磁耦合谐振原理的无线电能传输技术对机器人进行非接触无线充电。发射线圈埋于室内固定某处,其上方放置扬声器,接收线圈安放在机器人底部。充电步骤为:机器人通过监测电池电压或用户发送手机短信的方式开启充电程序,同时触发能量发射系统语音播放单元,使其播放语音指令呼叫机器人充电;机器人利用DSP实时采集语音信号,并通过声源定位算法判断发射系统方向,利用DSP进行驱动控制,指导其寻找发射源;当机器人进入发射源指定区域范围内,便可实现无线充电。该系统具有自主移动寻源和非接触无线充电的特点,无需人为干预,机器人可在几十秒内快速找到发射源并实现自主无线充电。     

基于生物行为模拟的知识处理系统研究

文章分析了新型知识处理系统所具有的自主性和创新性,提出了基于生物行为模拟的知识处理系统的概念,构建了相应的系统框架模型,并阐述了其功能单元构成和组织体系结构,对系统实现过程中所应面临的技术难题进行了初步探讨。     

Comparison of expression systems in the yeasts Saccharomyces cerevisiae,Hansenula polymorpha,Klyveromyces lactis,Schizosaccharomyces pombe and Yarrowia lipolytica. Cloning of two novel promoters from Yarrowia lipolytica

We have compared expression systems based on autonomously replicating vectors in the yeasts Saccharomyces cerevisiae, Schizosaccharomyces pombe, Kluyveromyces lactis, Hansenula polymorpha and Yarrowia lipolytica in order to identify a more suitable host organism for use in the expression cloning method (Dalbøge and Heldt-Hansen, 1994) in which S. cerevisiae has traditionally been used. The capacity of the expression systems to secrete active forms of six fungal genes encoding the enzymes galactanase, lipase, polygalacturonase, xylanase and two cellulases was examined, as well as glycosylation pattern, plasmid stability and transformation frequency. All of the examined alternative hosts were able to secrete more active enzyme than S. cerevisiae but the relative expression capacity of the individual hosts varied significantly in a gene-dependent manner. One of the most attractive of the alternative host organisms, Y. lipolytica, yielded an increase which ranged from 4·5 times to more than two orders of magnitude. As the initially employed Y. lipolytica XPR2 promoter is unfit in the context of expression cloning, two novel promoter sequences for highly expressed genes present in only one copy on the genome were isolated. Based on sequence homology, the genes were identified as TEF, encoding translation elongation factor-1α and RPS7, encoding ribosomal protein S7. Using the heterologous cellulase II (celII) and xylanase I (xylI) as reporter genes, the effect of the new promoters was measured in qualitative and quantitative assays. Based on the present tests of the new promoters, Y. lipolytica appears as a highly attractive alternative to S. cerevisiae as a host organism for expression cloning. GenBank Accession Numbers: TEF gene promoter sequence: AF054508; RPS7 gene promoter sequence: AF054509. © 1998 John Wiley & Sons, Ltd.     

信息技术环境下学生自主学习的实验与研究

学习活动不是在一个设计好的、以教师为中心的环境里获取信息的过程。当学生对学习产生了浓厚的兴趣,当他们切实参与了各项学习活动时,他们的学习效率就会得到很大提高。对在信息化的教学环境下,高校师生如何充分利用各种资源,进行高效教学活动,创建一种基于多媒体作品制作的教学方式进行了研究。