A calculation of the relative protonation energies of amines in solution

Relative protonation energies in the primary, secondary and tertiary aliphatic series of amines are calculated by a semiempirical method employing the virtual charge model. The method accounts quite well for the observed differences between the gas-phase protonation affinities and the protonation enthalpies in solution, but when allowance is made for steric shielding from the bulk solvent for “non-edge” atoms, some anomalies in the uncorrected model are removed. The calculated solute-solvent interactions are related to experimental enthalpies of solution and to trends expected from the Born model.     

生物质裂解产物的制备及HPLC检测其成分的虚拟仿真实验开发

In order to improve university laboratory teaching and practical education under the background of information technology, as well as overcome the difficulty for practical training, develop a virtual simulation experiment platform for rapid pyrolysis of natal materials and high-performance liquid chromatographic (HPLC) detection of its components. The experiment integrates the actual operation process of the plant to produce cleaved products by rapid pyrolysis of biomass with HPLC detection. The virtual experiment is divided into biomass sample pretreatment, rapid biomass pyrolysis, bio-oil extraction, and HPLC determination of complex components, making the biomass cleavage workshop "real" through simulation. This virtual simulation experiment fully integrates the utilization of biomass resources and basic chemistry courses (such as organic chemistry, instrumental analysis, chemical engineering principles, etc.), which are widely involved in agricultural and forestry majors with advantageous characteristics value.     

基于组态虚拟仿真技术的水箱液位实验

为节约自动化实验设备成本,提出了基于组态虚拟仿真技术的水箱液位实验方案。采用OPC通信技术实现 Matlab与组态王的数据交换,由Matlab实现算法的分析和计算,在组态王中进行可视化的画面实时监控、操作等,并以双容水箱液位实验进行物理实物和虚拟仿真的实验对比验证。实验比较结果表明,组态虚拟仿真实验技术既能体现出控制算法的分析与计算,又能较好地监控实验对象的实时运行状态,实现了与实物物理实验的同质等效。     

“线上线下-虚实结合”在有机化学实验教学中的应用探索——以正溴丁烷的制备实验为例

In response to the impact of the Covid-19 epidemic on organic chemistry laboratory teaching, this article analyzes and discusses the current limitation of traditional organic chemistry laboratory teaching. Taking the "preparation of n-bromobutane" as an example, a new "online-offline and virtual-actual combination" teaching mode with the combination of "Tencent Meeting, MLabs, laboratory and WeChat group" is introduced. The practice of the new mode of teaching includes the following steps: pre-class online guiding by teacher, student preview and practice based on the virtual simulation platform, students and teacher discussion and operation in laboratory, and post-classcomprehensive assessment and Q&A", and good teaching effects have been received. It is significant in cultivating and improving the independent innovation and practical ability, and provides reference for the organic chemistry laboratory teaching reform and also lays a foundation for the construction of "outstanding course" of organic chemistry.     

虚拟标准显色设备——跨网络色彩重现的新方案

随着网络的普及和多媒体应用的增长,彩色的传输和真实重现日益受到重视.虽然基于ICC的色彩管理提供了色彩复制与传递机制,但是这些技术仍存在增加系统开销、设备特性信息传递困难、不同色彩管理系统难以混合等问题.本文提出了"虚拟标准显色设备"的概念,较好地解决了跨网络、跨平台的色彩重现问题.实验结果证明了这种方法的有效性.     

Bipartite flocking for multi-agent systems

This paper addresses the bipartite flock control problem where a multi-agent system splits into two clusters upon internal or external excitations. Using structurally balanced signed graph theory, LaSalle’s invariance principle and Barbalat’s Lemma, we prove that the proposed algorithm guarantees a bipartite flocking behavior. In each of the two disjoint clusters, all individuals move with the same direction. Meanwhile, every pair of agents in different clusters moves with opposite directions. Moreover, all agents in the two separated clusters approach a common velocity magnitude, and collision avoidance among all agents is ensured as well. Finally, the proposed bipartite flock control method is examined by numerical simulations. The bipartite flocking motion addressed by this paper has its references in both natural collective motions and human group behaviors such as predator–prey and panic escaping scenarios.     

Simple laser vision sensor calibration for surface profiling applications

Due to the relatively large structures in the Oil and Gas industry, original equipment manufacturers (OEMs) have been implementing custom-designed laser vision sensor (LVS) surface profiling systems as part of quality control in their manufacturing processes. The rough manufacturing environment and the continuous movement and misalignment of these custom-designed tools adversely affect the accuracy of laser-based vision surface profiling applications. Accordingly, Oil and Gas businesses have been raising the demand from the OEMs to implement practical and robust LVS calibration techniques prior to running any visual inspections. This effort introduces an LVS calibration technique representing a simplified version of two known calibration techniques, which are commonly implemented to obtain a calibrated LVS system for surface profiling applications. Both calibration techniques are implemented virtually and experimentally to scan simulated and three-dimensional (3D) printed features of known profiles, respectively. Scanned data is transformed from the camera frame to points in the world coordinate system and compared with the input profiles to validate the introduced calibration technique capability against the more complex approach and preliminarily assess the measurement technique for weld profiling applications. Moreover, the sensitivity to stand-off distances is analyzed to illustrate the practicality of the presented technique.     

The (S−1,S) inventory model and its counterparts in queueing theory

We explore the relationship between the ($S?1,S$) inventory model and three well-known queueing models: the Erlang loss system, the machine-repair model and a two-node Jackson network. Exploiting this relationship allows us to obtain key performance measures of the ($S?1,S$) model, like the so-called virtual outdating time, the number of items on the shelf in steady state, the long-run rate of unsatisfied demands and the distribution of the empty shelf period.     

虚拟现实技术对教育领域的启示

这几年,一种信息交换方式再次成为业界关注的热点,那就是虚拟现实技术(Virtual Reality),特别是Facebook用20亿美元收购虚拟现实头盔制造商Oculus,让这块蛋糕的市场价值瞬间提升,同时也引爆了整个产业链.相比之下,我国虚拟现实技术还仅仅处于高校科研阶段,在普通教育阶段运用虚拟现实技术还面临着巨大的难题,本文将对教育领域的虚拟现实技术的运用谈谈自己的理解,供大家参考.     

带虚拟LED功能的多屏控制系统设计

本文设计了一种带虚拟LED功能的多屏控制系统。介绍了虚拟LED功能的实现原理和实现方法;阐述了系统启动和虚拟LED功能的实现流程。将虚拟LED功能集成到多屏控制系统中,可以解决指挥中心大屏幕和LED显示屏两套设备、两套软件的问题。带虚拟LED功能的多屏控制器使得大屏幕系统的安装更方便、操作更简便、稳定性更高。