9,859 research outputs found

    Analytical Potential Energy Function for the Ground State X^{1} Sigma^+ of LaCl

    Full text link
    The equilibrium geometry, harmonic frequency and dissociation energy of lanthanum monochloride have been calculated at B3LYP, MP2, QCISD(T) levels with energy-consistent relativistic effective core potentials. The possible electronic state and reasonable dissociation limit for the ground state are determined based on atomic and molecular reaction statics. Potential energy curve scans for the ground state X^{1} Sigma^+ have been carried out with B3LYP and QCISD(T) methods due to their better performance in bond energy calculations. We find the potential energy calculated with QCISD(T) method is about 0.5 eV larger than dissociation energy when the diatomic distance is as large as 0.8 nm. The problem that single-reference ab initio methods don't meet dissociation limit during calculations of lanthanide heavy-metal elements is analyzed. We propose the calculation scheme to derive analytical Murrell-Sorbie potential energy function and Dunham expansion at equilibrium position. Spectroscopic constants got by standard Dunham treatment are in good agreement with results of rotational analyses on spectroscopic experiments. The analytical function is of much realistic importance since it is possible to be applied to predict fine transitional structure and study reaction dynamic process.Comment: 10 pages, 1 figure, 3 table

    A Conceptual Model for Virtual Organizational Learning

    Get PDF

    State estimation based on unscented Kalman filter for semi-active suspension systems

    Get PDF
    In this paper, a novel approach to estimate vehicle vibration state information in real time is proposed; it is based on unscented Kalman filter (UKF) theory. The UKF is based on the unscented transfer technique which considers high order terms during the measurement and update stage during the estimation. The proposed observer uses easily accessible measurements such as accelerations and suspension deflections to estimate the sprung and unspring mass vertical velocity for the suspension systems of full vehicle under unknown road disturbance. And it is with low sensitivity and robust to the unknown road surfaces. Matlab/Carsim co-simulation experiments are carried out to validate the performance of the estimator under two typical road excitations. The simulation results clearly indicate that the proposed UKF sate observer is precise

    Neutral network-PID control algorithm for semi-active suspensions with magneto-rheological damper

    Get PDF
    In this paper, a semi-active suspension control system based on Magneto-Rheological (MR) damper is designed for a commercial vehicle to improve the ride comfort and driving stability. A mathematical model of MR damper based on the Bouc-Wen hysteresis model is built. The mathematical model could precisely describe the characteristics of MR damper compared with the bench test results. The neural network-PID controller is designed for the semi-active suspension systems. According to the numerical results, the proposed controller can constrain vehicle vibrations and roll angle significantly. A detailed multi-body dynamic model of the light vehicle with four semi-active suspensions are established, and an actual vehicle handling and stability tests are carried out to verify the control performances of the proposed controller. It can be concluded that MR semi-active suspension systems can play a key role in coordination between the ride comfort and handling stability for the commercial vehicle

    What Drives Workers to Learn Online during COVID 19 Pandemics?

    Get PDF
    One of the common practices during the COVID-19 pandemic is to work or study from home. This study aims to reexamine the factors affecting individual continuance intention of e-learning. During the pandemic, via a survey conducted in 2022, we assessed workers’ continuance intention of e-learning from different sectors in Taiwan. This research brought motivations as mediators in continuance intention to e-learning. Through the statistical analysis, we identified the mediation effect of motivations based on the self-determination theory. The results show that autonomous motivation facilitates the learners’ computer self-efficacy, the quality of the system and content toward continuance intention; controlled motivation could mediate the monetary award in influencing the continuance intention. The internalization of motivation is also an effective mediator. The obtained results not only add new knowledge of what affected the continuance intention of e-learning during the pandemic but also provide guidance for employers to allocate resources to boost e-learning after the pandemic

    Analysis on Parameters of Regeneration Subsystem in Liquid Desiccant Dehumidification Systems

    Get PDF
    Along with the widely use in industries and lives, the dehumidification systems have consumed a large amount of energy. Fortunately, the application of liquid desiccant dehumidification system can greatly reduce the consumption of high-grade energies. To improve the advantages of liquid desiccant system compared with the conventional dehumidification system, one of the key measures is to increase the efficiency of the regeneration sub-system. In this study, models for the regeneration tower and counter-current heat exchanger, which are recognized by previous experiments, are employed and the corresponding VC++ computer program modules are used to describe the heat and mass transfer processes between the liquid desiccant solution and moist air in the regenerator and the heat transfer process in heat exchanger respectively. The orthogonal design is used to arrange the numerical experiment. The results are analyzed by the method of variance analysis to determine the relative significance of operating parameters and the interactions between them. The analysis on the influence factors shows that for the evaporation rate of water vapor in the regenerator, the important parameters are the inlet temperature and concentration of the solution, the mass flow ratio of dry air to dehydrated desiccant, and the NTU of the regenerator. For the regeneration efficiency, the mass flow ratio of dry air to dehydrated desiccant, the NTU of the regenerator and inlet temperature of solution are important parameters. There is no interaction that influences the evaporation rate of water vapor and the regeneration efficiency significantly

    Investigating the Knowledge-Sharing Behavior ina Professional Virtual Community

    Get PDF
    This research aims at investigating the knowledge sharing-behaviors in a teachers’ professional virtual community. Logs data in the entire community and in special interest groups (SIGs) were analyzed. Some typical behaviors were identified by the clustering analysis in this study. The largest group of member belongs to inactive users. They rarely log in the system, are passive in uploading or downloading teaching materials, and almost never post or reply messages. Another group is active in receiving knowledge while reluctant to give knowledge or to respond. The third group frequently login the system, is the most active in sharing knowledge, and actively searching knowledge. However, the third group contains only a small number of members. Furthermore, fifty-five members of the knowledge-sharing group were interviewed using focus group technique to find out qualitative information as to why they are willing to share information and what are their concerns in sharing information. The results indicated that knowledge sharing is not a common behavior in professional virtual community, and knowledge-sharing culture is difficult to promote even in non-competitive professional communities. Secondly, knowledge cannot flow easily throughout the community even when certain knowledge flow promoting mechanism is provided. Thirdly, professional autonomy may hinder the frequency of interactions with others in professional virtual community. Fourthly, attitudes regarding information ownership are important factors in knowledge sharing of a professional virtual community. Finally, teaching and IT usage experiences are not major factors affecting knowledge-sharing behavior in pro fessional virtual communities
    • 

    corecore