Deployment Dynamic Modeling and Driving Schemes for a Ring-Truss Deployable Antenna

Mesh reflector antennas are widely used in space tasks owing to their light weight,high surface accuracy,and large folding ratio.They are stowed during launch and then fully deployed in orbit to form a mesh reflector that transmits signals.Smooth deployment is essential for duty services;therefore,accurate and efficient dynamic modeling and analysis of the deployment process are essential.One major challenge is depicting time-varying resistance of the cable network and capturing the cable-truss coupling behavior during the deployment process.This paper proposes a general dynamic analysis methodology for cable-truss coupling.Considering the topological diversity and geometric nonlinearity,the cable network's equilibrium equation is derived,and an explicit expression of the time-varying tension of the boundary cables,which provides the main resistance in truss deployment,is obtained.The deployment dynamic model is established,which considers the coupling effect between the soft cables and deployable truss.The effects of the antenna's driving modes and parameters on the dynamic deployment performance were investigated.A scaled prototype was manufactured,and the deployment experiment was conducted to verify the accuracy of the proposed modeling method.The proposed methodology is suitable for general cable antennas with arbitrary topologies and parameters,providing theoretical guidance for the dynamic performance evaluation of antenna driving schemes.

不同丙烯腈含量丁腈橡胶在海水中的动静态溶胀行为

通过悬挂式浸泡装置和橡胶冲击试验机考察了3种不同丙烯腈含量的丁腈橡胶(N18、N26和N41)在海水中的动、静态溶胀行为。利用傅里叶变换红外光谱、能量色散谱、场发射扫描电镜对溶胀试件结构和形貌进行了表征,并利用伺服拉力机进行了力学性能测试。通过水溶胀对比试验揭示了海水对橡胶静态溶胀行为的影响,通过冲击试验比较了动、静态溶胀状态下橡胶试件的质量变化率(MCF)。结果表明,与水溶胀行为相比,橡胶在氯化钠溶液中的静态溶胀程度更低,MCF最小值为0.133%来自于N41试件。然而,氯化钠溶液中的离子在橡胶内部扩散使其表面成分发生变化,硬度略微提高,硬度增量的最小值来自于N41试件为0.2 Shore A。动态溶胀试验的MCF值是静态溶胀的2～4倍,最小动态MCF值0.316%同样来自于N41试件。最后,阐述了溶胀对丁腈橡胶力学性能的影响,揭示了冲击与溶胀的相互关系,并探讨了丙烯腈对丁腈橡胶耐溶胀性的作用。

Postoperative secondary aggravation of obstructive sleep apneahypopnea syndrome and hypoxemia with bilateral carotid body tumor:A case report

BACKGROUND Carotid body tumor(CBT)is a chemoreceptor tumor located in the carotid body,accounting for approximately 0.22%of head and neck tumors.Surgery is the main treatment method for the disease.CASE SUMMARY We reviewed the diagnosis and treatment of one patient who had postoperative secondary aggravation of obstructive sleep apnea–hypopnea syndrome(OSAHS)and hypoxia after surgical resection of bilateral CBTs.This patient was admitted,and relevant laboratory and imaging examinations,and polysomnography(PSG)were performed.After the definitive diagnosis,continuous positive airway pressure(CPAP)treatment was given,which achieved good efficacy.CONCLUSION This case suggested that aggravation of OSAHS and hypoxemia is possibly caused by the postoperative complications after bilateral CBTs,and diagnosis by PSG and CPAP treatment are helpful for this patient.

Sensorless Control of Double-sided Linear Switched Reluctance Motor Based on Simplified Flux Linkage Method

The utilization of position sensor reduces the system reliability of switched reluctance motor(SRM),especially in harsh environments.It also increases the complexity of the system.Therefore,the research on sensorless control has become one of the hot spots in recent years.Comparing with the existing sensorless control technology,the new method exploring the sensorless control of double-sided linear switched reluctance motor(DLSRM)shows the following advantages:1)high accuracy,and 2)good practicability.Based on the new proposed method,the DLSRM speed controller is augmented with the peak current method and the voltage chopping closed-loop speed control.Moreover,the winding resistance in the equation is corrected according to the integral flux linkage when the phase current is zero.The accuracy and feasibility of the simplified flux linkage method in estimating the position of the DLSRM is verified.

A novel fractional grey forecasting model with variable weighted buffer operator and its application in forecasting China's crude oil consumption

Oil is an important strategic material and civil energy.Accurate prediction of oil consumption can provide basis for relevant departments to reasonably arrange crude oil production,oil import and export,and optimize the allocation of social resources.Therefore,a new grey model FENBGM(1,1)is proposed to predict oil consumption in China.Firstly,the grey effect of the traditional GM(1,1)model was transformed into a quadratic equation.Four different parameters were introduced to improve the accuracy of the model,and the new initial conditions were designed by optimizing the initial values by weighted buffer operator.Combined with the reprocessing of the original data,the scheme eliminates the random disturbance effect,improves the stability of the system sequence,and can effectively extract the potential pattern of future development.Secondly,the cumulative order of the new model was optimized by fractional cumulative generation operation.At the same time,the smoothness rate quasi-smoothness condition was introduced to verify the stability of the model,and the particle swarm optimization algorithm(PSO)was used to search the optimal parameters of the model to enhance the adaptability of the model.Based on the above improvements,the new combination prediction model overcomes the limitation of the traditional grey model and obtains more accurate and robust prediction results.Then,taking the petroleum consumption of China's manufacturing industry and transportation,storage and postal industry as an example,this paper verifies the validity of FENBGM(1,1)model,analyzes and forecasts China's crude oil consumption with several commonly used forecasting models,and uses FENBGM(1,1)model to forecast China's oil consumption in the next four years.The results show that FENBGM(1,1)model performs best in all cases.Finally,based on the prediction results of FENBGM(1,1)model,some reasonable suggestions are put forward for China's oil consumption planning.