澳大利亚进口焦煤煤质特性与结焦特性研究

通过质量检测、煤的岩相分析和20kg试验焦炉炼焦试验，对澳大利亚两种进口焦煤诺维茨煤和峰景煤的煤质和结焦特性进行了研究，两种进口焦煤低灰、低硫，为单一煤层煤，煤质稳定，配煤炼焦有利于焦炭质量稳定。峰景煤和国内柳湾煤的结焦性能相当，诺维茨煤的结焦性能与国内恒山煤和祁县煤的结焦性能接近。     

Learning With Weblogs: Enhancing Cognitive and Social Knowledge Construction

This study investigated the impact of weblog use on individual learning in the context of university senior-level business education. As an emergent form of personal communication, weblogs enable people to publish their thoughts as webpages, and to share information and knowledge. Recognizing the potential impact of weblogs on knowledge expression and sharing, this research sought to empirically examine whether the continuous use of weblogs as online learning logs would affect student learning performance. The assumption was that effective use of weblogs promoted the constructivist models of learning by supporting both cognitive and social knowledge construction, and by reinforcing individual accountability in learning. Results from an Information Systems undergraduate course with 31 participants indicated that the performance of students' weblogs was a significant predictor of the learning outcome (while traditional coursework was not). Moreover, individuals' cognitive construction effort to build their own mental models and social construction effort to further enrich/expand knowledge resources appeared to be two key aspects of the constructivist learning with weblogs. Our results imply the potential benefit of using weblogs as a knowledge construction tool and a social learning medium     

折反光学系统最佳红外像面位置的研究

较深入地研究了折反光学系统的红外像面,为确定实际的红外像面提出了一个新方法—计算从可见光边缘无色的弥散圆到红外最佳像面的距离。实践证明,这是确定这类光学系统最佳像面的一个方便、可靠的方法。     

RADIOACTIVE OR NATURAL TRACER。TECHNIQUES FOR LEAK DETERMINING OF DAM ABUTMENT

Infiltration and localization of preferential infiltration zones at the dam abutment are measured using radioactive tracer tests of flow in boreholes,meanwhile interconnection between boreholes and the energing water points is analysed.The theory and practice of radioactive tracer synthetic detective method are described to give methods and calculation formulae used under the condition of stable flow in single well to measure permeability coefficient and hydrostatic heads.Major single hole techniques including measurement for seepage line,velocity,rate of seepage flow and relationship of recharge of groundwater in aquifers are introduced briefly.The possibilities offered by natureal tracers are analysed,uincluding electric-conduct,pH-value and temperature of water as well as stable isotopes(D,^18O) and tritium.Furthermore,the sensibilities of this theory and methods were confirmed by detecting seepage flow field of Xinanjiang Dam.     

精品课程教学录像的建设现状分析与建议

教学录像是精品课程建设的重要内容之一。为了开发集教学性、科学性、技术性与艺术性于一体的精品课程教学录像,针对精品课程教学录像的性质,参照其上网技术指标及网上浏览的特点,对其建设现状进行分析,并提出了精品课程教学录像建设的建议。     

Toward practical adoption of i* framework: an automatic two-level layout approach

Requirements Engineering - Bridging the gap between academia and industry is an important issue to promote the practicality of i* framework. Researchers have been dealing with this issue from...     

Image cipher using image filtering with 3D DNA-based confusion and diffusion strategy

Neural Computing and Applications - In this paper, an image cipher is presented based on DNA sequence operations, image filtering and memrisitve chaotic system. Firstly, plain image is preprocessed...     

Exploiting 2D compressed sensing and information entropy for secure color image compression and encryption

Neural Computing and Applications - Compared to 1D compressed sensing (CS), 2D CS is more efficient for compressing the plaintext image from two directions, but security level of current 2D...     

基于双闭环系统的起重机位置控制技术研究

传统的起重机位置控制技术大多是以位移或速度为反馈量构成的单闭环控制,只能对系统的一个状态量进行控制,易造成系统的超调、振荡,难以实现真正意义上的位置控制;研究采用位移和速度的双闭环位置控制技术[1],以位移环为外环、速度环为内环,位移环根据位移的当前值与给定值的差,通过位移调节器给速度环提供给定速度,速度环通过速度调节器控制系统的运动速度,最终实现对系统的位置控制;通过对单闭环控制和双闭环控制的仿真结果对比分析,双闭环系统的位置和速度的控制精度均比单闭环精度高,最后通过实验,证明了双闭环系统在实践上的可行性。