双级贯流式水轮机导叶和转轮的水力设计

针对一种新型双级贯流式水轮机,推导了一级导叶、一级转轮、二级导叶和二级转轮的参数设计公式。利用数值模拟商业软件Fluent分析了水轮机在设计工况下的数值性能。数值计算时控制方程采用雷诺时均N-S离散方程,湍流模型选择标准k-ε模型,得到了水轮机的流线图、导叶和转轮叶片的压力面和吸力面的压力分布图,以及中心对称面x=0.083 5的速度矢量图,数值计算结果证明了水轮机设计的正确性。     

基于SMW工法的城市深基坑开挖稳定性分析

SMW工法具有防渗性好、构造简单、施工速度快、工程造价低等优点,广泛应用于大型隧道工程、城市地下空间开发、高层建筑深基坑开挖支护工程等。以某城市深基坑工程的SMW工法围护结构为研究对象,在考虑水泥土与型钢的相互作用下,建立有限元数值模型,分析开挖过程中墙体位移和土体变形特点。结果表明:开挖深度对墙体侧向位移有显著影响;随着坡面荷载的增加,基坑内外水平方向和竖直方向沉降量均有所增大。     

Infections due to Lancefield group F and related Streptococci (S. milleri, S. anginosus)

We can no longer accept classification of streptococci solely on the basis of hemolytic reactions or Lancefield agglutinations. While the "viridans" streptococci cannot be serologically differentiated, physiological separation of the species offers a satisfactory method of classifying human isolates. We review the microbiology of Lancefield group F and related streptococci (S. milleri, S. anginosus), emphasizing microbial ecology and current taxonomic considerations. A series of 28 patients infected with these organisms is presented. There was a striking male predominance in the series (6:1) as well as an obvious association with underlying diseases and/or antecedent trauma. The most remarkable feature of these pathogens is their predilection for abscess formation, confirming their overdue recognition as the most common "viridans" streptococcus recovered from abscesses within internal organs. We observed purulent disease of the nervous and skeletal systems, oral cavity, lung and pleural space, abdomen and subcutaneous tissues. Microbial synergy (i.e. polymicrobic infection) was not a requisite for abscess formation. Four of the five deaths in this series occurred in patients 60 years of age of older. Some degree of variability in antimicrobial susceptibility was noted, so speciation alone may not always provide sufficient information on which to base a therapeutic decision.     

基于FPGA的超高速FFT硬件实现

介绍了频域抽取基二快速傅里叶运算的基本原理;讨论了基于FPGA达4 096点的大点数超高速FFT硬件系统设计与实现方法,当多组大点数进行FFT运算时,利用FPGA内部大容量存储资源,采用乒乓结构进行流型运算,提高FFT运算速度,同时保证结果的准确性;对实际硬件进行了FFT运算测试,测试结果证明了系统的可行性和正确性,并且利用该硬件系统成功完成了星载SAR实时成像处理。     

4,5-二溴邻硝基苯基荧光酮与锌显色反应的研究及应用

在CTMAB存在下,研究了4,5-二溴邻硝基苯基荧光酮(DBON PF)与锌的显色反应。试验表明,在pH8.0的氨性缓冲溶液中,锌与DBON PF形成1∶2的红色络合物,该络合物的最大吸收波长为595nm,其表观摩尔吸光系数为6.87×104,有色络合物稳定24h以上;25mL溶液中,锌质量在0～10μg范围内符合比尔定律;用锌-DBON PF-CTMAB体系显色测定微量锌,方法灵敏度高,选择性好,测定铁矿样中微量锌,结果满意。     

淮北矿业集团工业电视图象远程传输系统的设计与实施

介绍了淮北矿业集团工业电视图象远程传输系统工程的设计、实施及主要特点。该系统采用模拟、数字两种传输形式 ,可实现图象传输、数字录像、录像查询等功能 ,为安全生产、调度指挥、科学决策、事故追查提供了直观、可靠的手段。     

Robocup小型足球机器人AI决策系统设计--Robocup系列研究之六

介绍了Robocup小型足球机器人的AI决策系统的分层式结构设计方案。重点阐述了信息处理层的设计，采用扩展卡尔曼滤波(EKF)对场上所有对象进行跟踪和预测，并介绍了责任区域划分和按责任区域划分决定战术决策选择的思想，通过对基本信息的处理运算建立了实时更新的信息库，为后续战术策略选择提供了信息和依据，     

Short answers to deep questions: supporting teachers in large‐class settings

In large class settings, individualized student–teacher interaction is difficult. However, teaching interactions (e.g., formative feedback) are central to encouraging deep approaches to learning. While there has been progress in automatic short‐answer grading, analysing student responses to support formative feedback at scale is arguably some way from being widely applied in practice. However, analysing student written responses can provide insights into student conceptions, thus directly informing teacher actions. Indeed, we argue that analysing student responses to provide feedback directly to teachers is as worthy a goal as providing individualized feedback to students and is achievable given the current state‐of‐the‐art in natural language processing. In this paper, we analyse student written responses to short‐answer questions posed in the context of a large first year health sciences course. Each question was designed to elicit deep responses. Our qualitative analysis illustrates the variability in student responses and reveals multiple relationships between these responses, course materials and the questions posed. Such information can be invaluable for teacher praxis. We conclude with a conceptual ‘dashboard’ that categorizes student responses and reveals relationships between responses, course resources and the questions. Such a dashboard could provide timely, actionable insights for teachers and help foster deep learning approaches for students.     

Theory as a source of software and system requirements

Requirements Engineering - Today, when undertaking requirements elicitation, engineers attend to the needs and wants of the user groups considered relevant for the software system. However, answers...     

"互联网+"下的智慧工地

随着社会生产力的不断发展,传统工程建设领域因其自身理念的落后,行业整体缺乏先进的互联网管理技术,在工程进程监督、质量检测、人员调配方面缺乏实时的分析手段,难以满足快速发展的需求."互联网+"理念与传统建设工程领域的深度融合,赋予传统工程建设领域以"智慧",利用物联网、云计算、BIM等信息化手段,对施工过程中人员、视频、质量、生产、环境等数据进行采集,最终实现互联协同、智能生产、科学管理等功能的智能化工程建设.