由二叉树遍历序列还原二叉树

遍历二叉树是"数据结构"课程中讨论的重要内容之一,通过对二叉树的四种不同遍历序列(即前序遍历序列、中序遍历序列、后序遍历序列、层次遍历序列)的具体分析,总结二叉树的四种遍历序列间的关系,解决怎样由二叉树的遍历序列还原二叉树的问题.     

Transgenic barley with overexpressed PTrx increases aluminum resistance in roots during germination

A transgenic barley line (LSY-11-1-1) with overexpressed Phalaris coerulescens thioredoxin gene (PTrx) was employed to measure the growth, protein oxidation, cell viability, and antioxidase activity in barley roots during germination on the presence of 2 mmol/L AlCl₃ on filter paper. The results show that (1) compared with the non-transgenic barley, LSY-11-1-1 had enhanced root growth, although both were seriously inhibited after AlCl₃ treatment; (2) the degree of protein oxidation and loss of cell viability in roots of LSY-11-1-1 were much less than those in roots of non-transgenic barley, as reflected by lower contents of protein carbonyl and Evans blue uptakes in LSY-11-1-1; (3) activities of catalase (CAT), glutathione peroxidase (GPX), ascorbate peroxidase (APX), and glutathione reductase (GR) in LSY-11-1-1 root tips were generally higher than those in non-transgenic barley root tips, although these antioxidase activities gave a rise to different degrees in both LSY-11-1-1 and non-transgenic barley under aluminum stress. These results indicate that overexpressing PTrx could efficiently protect barley roots from oxidative injury by increasing antioxidase activity, thereby quenching ROS caused by AlCl₃ during germination. These properties raise the possibility that transgenic barley with overexpressed PTrx may be used to reduce the aluminum toxicity in acid soils.     

远程开放教育英语学习者辍学研究

本研究针对广东地区远程开放教育英语本科辍学者,采用个体访谈形式调查、剖析辍学者辍学的心理动因,对辍学现象进行全方位的深描,试图通过辍学者的个人体验和意义阐释,探求远程英语学习者的辍学原因。对访谈内容采用内容分析方法进行分析。研究发现,影响远程开放教育英语本科学习者放弃学业的主要因素是:情感在场的影响、情感交互程度低、工学矛盾。本研究试图为远程教育实践机构有的放矢地制定相关措施,减少辍学人数提供有益参考。     

耐热木聚糖酶源细菌筛选、鉴定及酶学性质

利用木聚糖作为唯一碳源的基础盐培养,在50℃培养条件下,从新乡周围土样及腐殖质中筛选到1株产耐热β-木聚糖酶细菌,初步鉴定为巨大芽孢杆菌（Bacillus megaterium FLH-2）.该菌株在40~55℃生长良好,最适生长温度50℃.木聚糖酶粗酶性质研究表明：该酶最适pH和最适温度分别为6.0和65℃;在pH 5.0~9.0及温度30~75℃之间酶活相对稳定,分别处理30 min,相对酶活仍保持在80%以上.     

跨民族文化新闻传播理念的认知与构建

本文探讨了在多民族文化共存的情况下,如何切实有效地实施新闻传播的问题.     

图书条码号宜兼作财产号

论文在分析财产号和条码号各自功能的基础上,立足于图书馆编目和管理工作的实际,指出图书条码号兼作财产号的必要与可行。     

Distributed event-triggered adaptive finite-time consensus control for second-order multi-agent systems with connectivity preservation

In this paper, we consider the robust finite-time consensus problem for second-order multi-agent systems (MASs) with limited sensing range and weak communication ability. As a stepping stone, a novel distributed finite-time sliding mode manifold is developed for MASs. Then, by combining artificial potential function technique with the presented sliding mode manifold, a robust distributed control scheme is proposed to enable the finite-time consensus of MASs while preserving the prescribed communication connectivity. Furthermore, the sampling frequency and implementation burden of the proposed controller can be reduced with resort to the event-triggered methodology. Finally, numerical examples are given to show the effectiveness of the proposed method.     

我国政府信息资源公共获取策略研究

政府信息资源公共获取是实现政务公开、保障公民知情权的重要保障。文章对我国政府信息资源公共获取的现状及其存在的问题进行了分析,并针对具体情况,从在《宪法》中进一步明确知情权、转变观念、完善信息公开制度、建立有效信息获取渠道、重视信息安全等方面,提出适宜我国政府信息资源公共获取的策略和措施。     

新型三级变速电动轮毂的研制

针对现有电动车不能适应复杂路况和动力轮转矩不够大的问题,通过在原有电动轮毂上加装机械变速箱来实现轮毂的三级变速,使新型轮毂获得更好的路况适应能力,并且可以根据需要换挡获得更快的速度或更大的转矩。本产品将机械变速箱集成在电动轮毂内,减小了新型三级变速电动轮毂的体积;单向飞轮的使用省去了离合器的使用,使变速过程变得简单易行,新型三级变速电动轮毂的动力性能得到了提高。     

开封市档案登记与备案工作的实践

2003年,按照《河南省档案管理条例》和《河南省档案管理登记与档案备案办法》的规定,我市开展了档案管理登记与备案工作。通过三年的工作实践,我们对档案登记与备案工作,有了更进一步的认识,更加坚定了做好这项工作的信念,明确了下一步努力的方向。