计量器具管理信息系统的设计与实现

针对现代企业中计量器具管理落后的状况,以Visual C++为编程工具,运用Access数据库,采用结构化方法,开发出计量器具管理信息系统。该系统包括登录模块、查询模块、量具信息管理模块、到期检定模块和报表打印模块等。用户可根据不同的查询方式获得所需信息,方便检测部门及时了解量具状态,做出检定计划。本系统的使用将更好地实现计量器具的统一、规范管理,提高量具管理效率。     

Evaluation of the real contact area in three-body dry friction by micro-thermal analysis

Many tribological properties and wear mechanisms occurring on the micro-and nanoscale are strongly controlled by the so-called real contact area (A_r) which is a small fraction of the nominal or apparent contact area (A_a). The determination of A_r is often based on either (i) a geometrical approach describing the real geometry of contacting surfaces or (ii) a mechanical approach involving contact mechanics and physical-mechanical properties. In addition some experimental methods have also been attempted but they generally do not take into account the presence of third body at the interface—i.e. the wear debris trapped within the contact. In this paper we propose an experimental approach to estimate the dynamic real contact area from the operating parameters (F_n, v, T) and the tribological responses (μ, F_t) in presence of third body. A scanning thermal microscope (SThM) is used for determining both the thermal conductivity of the third body and the relationship between the contact temperature and the thermal power really dissipated at the micro-asperity level. These results are combined with a thermal model of the macro-tribocontact for computing the real contact area and the real contact pressure. Validation of these results is carried out using a classical Greenwood Williamson model and finite element models built from the real AFM maps.     

基于多绕组永磁发电机的大容量级联型风力发电变换器

针对大容量风电机组的中压变换问题,提出了一种基于多绕组永磁发电机的级联型变换器系统,通过模块单元级联实现中压输出,从而省去升压变压器.将模块中发电机的两个正交绕组经PFC整流后在直流母线上并联,实现发电机单位功率因数运行,并保持馈入直流母线的瞬时功率恒定.利用发电机的电枢电感作为升压电路的储能电感,减小了系统的体积和成本,导出了电感取值的适用范围.逆变侧的H桥单元级联电路采用矢量控制,独立调节注入电网的有功和无功功率.仿真和实验结果验证了该类变换器拓扑结构和控制方法的有效性.     

永磁同步电动机电磁转矩的计算

介绍两种永磁同步电动机电磁转矩的计算方法,即麦克斯韦应力张量法和磁通法。两种方法均是通过有限元原理来求取电磁转矩。计算了永磁同步电机在不同工作状态下的电磁转矩,并且将两种方法进行对比,最后取得较好的效果。     

基于VC-DRSA的信息系统多属性群决策安全评估

以某高校校园网络系统作为评估样本,在建立了信息系统安全属性模型的基础上,提出了基于变一致性优势关系粗糙集（VC—DRSA）的多属性群决策的安全评估方法。该方法将VC-DRSA与层次分析法（AHP）相结合,利用VC-DRSA分类质量的概念挖掘出隐含在数据背后的内在规律,在确定安全属性权重的基础上,对信息系统进行了综合安全评估。实例计算证明,该方法可以有效地解决多属性群决策的“瓶颈”问题,在信息系统安全评估中具有实际意义。     

A green approach for cohesive recycling and regeneration of electrode active materials from spent lithium-ion batteries

The implementation of the green energy transition by reducing reliance on fossil fuels has fueled the burgeoning demand for lithium-ion batteries in grid-level energy storage systems and electric vehicles. The growth of portable electronic devices has also contributed to this exponential demand, creating both logistical and environmental challenges in the supply of raw materials such as lithium and the management of end-of-life batteries. Current recycling methods for spent batteries are both energy-intensive and inefficient. To address these issues, a green approach using organic acid mixtures has been proposed to reclaim lithium from spent cathodes and recover and purify graphite from spent anodes, while also regenerating its structure. The effectiveness of this method is demonstrated through the use of organic acid mixtures to leach and reclaim lithium from NCM 622 batteries. On the anode side, a curing–leaching strategy using organic acids is employed to purify spent graphite, which is subsequently calcined to enhance its interlayer structure conducive to better intercalation of Li⁺ and improve electrochemical performance. Additionally, recovered graphite is tailored with carbon using water bath carbonization to repair structural defects caused by lithium intercalation and improve electrochemical performance while augmenting the regenerated graphite's quality, equipping it to be reused in batteries or upcycled applications.     

Shaping futures: A dialogue on chemical engineering education

Engineering as a discipline, profession, practice, and area of study continues to add substantial value in an increasingly complex world. With continually evolving complexity around the planet, such as the need for massive energy transition, global health technologies, or sustainable food systems, how might engineering education practices and theory be considered within these rapid and necessary changes? This paper presents an experiment of co-creation through experiential reflection about the state of chemical engineering education. Four chemical engineering professors engaged in a dialogue, facilitated by a researcher in education, through collaborative and actionable research. This dialogue uncovered innovative possibilities, educational themes, experiences, and opportunities for others in the profession to consider. The process of dialogue also encouraged the development of an imaginative future sense-making, known as futuring, through a collective experience. The findings reveal instructive perspectives on the shape of chemical engineering education that should be of value not only to engineers, but also other professionals, practitioners, or those in various science, technology, and math fields.     

“信号与系统”中三个层次教学探索

"信号与系统"课程内容和结构体系的特点之一就是具有思维方式的训练和培养.本文从教学层次、教学方法以及具体的教学内容和过程,讨论了"信号与系统"教学过程中创造性思维培养的问题.本文所讨论的方式方法的效果在多年的教学实践中得到了证明,同时得到学生及专家的肯定.     

朱熹传播科学知识的途径

朱熹在其学术生涯中,通过各种途径传播科学知识。他或是通过传注经典,或是通过授徒讲学,传播自然知识和科学思想,而且,他还曾编校过通俗天文学著作《步天歌》。朱熹的科学知识传播,对于当时的科技发展起了积极的作用。