Multi-objective Optimization Design of Wing Structure with the Model Management Framework

AbstractEvolutionary algorithm is time-consuming because of the large number of evolutions and much times of finite element analysis, when it is used to optimize the wing structure of a certain high attitude long endurance unmanned aviation vehicle(UAV). In order to improve efficiency it is proposed to construct a model management framework to perform the multi-objective optimization design of wing structure. The sufficient accurate approximation models of objective and constraint functions in the wing structure optimization model are built when using the model management framework, therefore in the evolutionary algorithm a number of finite element analyses can be avoided and the satisfactory multi-objective optimization results of the wing structure of the high altitude long endurance UAV are obtained

Measurement of the Euler Angles of Wurtzitic ZnO by Raman Spectroscopy

A Raman spectroscopy-based step-by-step measuring method of Euler angles φ,θ,and  ψ was presented for the wurtzitic crystal orientation on a microscopic scale. Based on the polarization selection rule and coordinate transformation theory, a series of analytic expressions for the Euler angle measurement using Raman spectroscopy were derived. Specific experimental measurement processes were presented, and the measurement of Raman tensor elements and Euler angles of the ZnO crystal were implemented. It is deduced that there is a trigonometric functional relationship between the intensity of each Raman bands of wurtzite crystal and Euler angle ψ, the polarization direction of incident light under different polarization configurations, which can be used to measure the Euler angles. The experimental results show that the proposed method can realize the measurement of Euler angles for wurtzite crystal effectively

Prediction and Study of Air Thermal Parameters in Unexploited Mine Regions Based on Temperature Prediction Model in Whole Ventilation Network

AbstractMines with heat disaster danger have been increased year by year, in order to provide basic data for mine air- conditioning design, prediction of air thermal parameters in the mine unexploited region becomes particularly important. But at present, prediction of air thermal parameters is realized mainly by empirical formula and forecast method of single-line(main trunk road method), existing many disadvantages such as strong individual subjectivity, bad theoretical property and low forecasting precision. Therefore, a kind of air temperature prediction model in whole ventilation network based on wind enthalpy equation is put forward. By the model, air temperature prediction software in whole ventilation network which can make reasonable forecast of thermal parameters for different high temperature mines is programmed by determining air thermal parameters through wind energy equation and considering the influence of natural wind pressure. Through the prediction of the air thermal parameters of the wind route in the fifth mining area in east wing of Dongtan colliery, it can be seen that air temperature prediction model in whole ventilation network is scientific, reasonable and with strong operating nature, which can meet the requirements of the prediction of air thermal parameters in unexploited region of high temperature mines

CoV Genome Tracker: tracing genomic footprints of Covid-19 pandemic

Genome sequences constitute the primary evidence on the origin and spread of the 2019-2020 Covid-19 pandemic. Rapid comparative analysis of coronavirus SARS-CoV-2 genomes is critical for disease control, outbreak forecasting, and developing clinical interventions. CoV Genome Tracker is a web portal dedicated to trace Covid-19 outbreaks in real time using a haplotype network, an accurate and scalable representation of genomic changes in a rapidly evolving population. We resolve the direction of mutations by using a bat-associated genome as outgroup. At a broader evolutionary time scale, a companion browser provides gene-by-gene and codon-by-codon evolutionary rates to facilitate the search for molecular targets of clinical interventions

Wide Distribution of a High-Virulence Borrelia burgdorferi Clone in Europe and North America

We found substantial population differentiation and recent trans-Atlantic dispersal of a high-virulence B. burgdorferi clone

Chaos Suppression of an Electrically Actuated Microresonator Based on Fractional-Order Nonsingular Fast Terminal Sliding Mode Control

This paper focuses on chaos suppression strategy of a microresonator actuated by two symmetrical electrodes. Dynamic behavior of this system under the case where the origin is the only stable equilibrium is investigated first. Numerical simulations reveal that system may exhibit chaotic motion under certain excitation conditions. Then, bifurcation diagrams versus amplitude or frequency of AC excitation are drawn to grasp system dynamics nearby its natural frequency. Results show that the vibration is complex and may exhibit period-doubling bifurcation, chaotic motion, or dynamic pull-in instability. For the suppression of chaos, a novel control algorithm, based on an integer-order nonsingular fast terminal sliding mode and a fractional-order switching law, is proposed. Fractional Lyapunov Stability Theorem is used to guarantee the asymptotic stability of the system. Finally, numerical results with both fractional-order and integer-order control laws show that our proposed control law is effective in controlling chaos with system uncertainties and external disturbances

Revealing of the Activation Pathway and Cathode Electrolyte Interphase Evolution of Li-Rich 0.5Li2MnO3·0.5LiNi0.3Co0.3Mn0.4O2 Cathode by in Situ Electrochemical Quartz Crystal Microbalance.

The first-cycle behavior of layered Li-rich oxides, including Li2MnO3 activation and cathode electrolyte interphase (CEI) formation, significantly influences their electrochemical performance. However, the Li2MnO3 activation pathway and the CEI formation process are still controversial. Here, the first-cycle properties of xLi2MnO3·(1- x) LiNi0.3Co0.3Mn0.4O2 ( x = 0, 0.5, 1) cathode materials were studied with an in situ electrochemical quartz crystal microbalance (EQCM). The results demonstrate that a synergistic effect between the layered Li2MnO3 and LiNi0.3Co0.3Mn0.4O2 structures can significantly affect the activation pathway of Li1.2Ni0.12Co0.12Mn0.56O2, leading to an extra-high capacity. It is demonstrated that Li2MnO3 activation in Li-rich materials is dominated by electrochemical decomposition (oxygen redox), which is different from the activation process of pure Li2MnO3 governed by chemical decomposition (Li2O evolution). CEI evolution is closely related to Li+ extraction/insertion. The valence state variation of the metal ions (Ni, Co, Mn) in Li-rich materials can promote CEI formation. This study is of significance for understanding and designing Li-rich cathode-based batteries