Fixed-time angle of attack constrained control for aircraft considering dynamic icing process.

Aircraft icing deteriorates aerodynamic performance and reduces stall angle of attack, the fast convergence rate of tracking error is required to stabilize the aircraft when aircraft icing occurs. The state-of-the-art control methods for icing aircraft mostly assume that the icing of aircraft is instantaneous. Aiming at these issues, a fixed-time angle of attack-constrained control strategy is designed considering dynamic icing process. In order to explore the variation of aerodynamic coefficients in the process of dynamic icing, an ice wind tunnel experiment is implemented, and the relationship between lift coefficient, drag coefficient and pitching moment coefficient with angle of attack and icing intensity is obtained by fitting method. In order to prevent the stalling problem caused by the decrease of the stalling angle of attack in the process of dynamic icing, a method to determine the stalling angle of attack based on deep neural network is proposed. Considering the asymmetric and time-varying angle of attack constraint, a fixed-time convergent angle of attack-constrained robust control method is designed. The ice wind tunnel experiment shows the process of dynamic icing of the airfoil, and the simulation results verify the effectiveness of the proposed control method.

The optimization method of wing ice shape regulation based on flight dynamics characteristics.

Ice on aircraft wing changes the aircraft aerodynamic shape, and has negative effects on flight dynamic characteristics, seriously threatening flight safety. Plasma ice shape regulation is a new de-icing method. Plasma actuator produces an apparent thermal effect, which is designed to dissolve the continuous ice into intermittent ice pieces. How to achieve the optimal regulation ice shape to improve the flight dynamics characteristics under icing conditions is a technical problem restricting the application of this method. A simulation ice shape based on previous ice tunnel experiments and a scale model of swept wing were established. The aerodynamic parameters of no ice, full ice, and two regulation ice schemes were obtained based on wind tunnel. Six degrees of freedom flight dynamics model was established, and flight simulation had been carried out. As the analysis of trim characteristics, dynamic stability, and maneuverability, flight dynamics characteristics were better improved when the ratio of ice width to the mean aerodynamic chord was 0.15. The evaluation method of plasma ice shape regulation schemes was proposed. The proposed method, which can compare and optimize the arrangement of plasma actuators, realized the optimal regulation ice shape on the premise of balancing flight safety and energy consumption.

Biogenic Amines and Predictive Models of Quality of Rainbow Trout ( Oncorhynchus mykiss ) Fillets during Storage.

To estimate biogenic amines and changes in quality of rainbow trout ( Oncorhynchus mykiss ) fillets at different temperatures, we determined the sensory attributes, total volatile basic nitrogen (TVB-N), total viable counts (TVC), and biogenic amines (BAs) of samples that were untreated (CK) or dry cured with 1.8% salt (T). There was no significant difference between CK and T samples in terms of TVB-N, TVC, and BAs. TVB-N and TVC increased significantly (P < 0.05) with storage time at 3, 9, and 15°C. Putrescine (PUT) and cadaverine (CAD) increased significantly (P < 0.05) at -3, 3, 9, and 15°C during storage. Histamine formed more easily when storage temperatures were higher. The kinetic models of sensory scores for TVB-N, TVC, PUT, CAD, and the sum of PUT and CAD (PUT+CAD) in T samples versus storage time and temperature were developed based on the Arrhenius equation. High regression coefficients (R2 > 0.9) indicated the acceptability of the kinetic model for predicting changes in the quality of the rainbow trout fillets. Relative errors between predicted and experimental values of TVB-N, TVC, and PUT+CAD were all within 10% except for TVB-N on day 6. The prediction model based on TVB-N, TVC, and PUT+CAD can be applied to evaluate changes in quality of rainbow trout fillets from -3 to 15°C (270 to 288 K).

Therapeutic effects of the smartphones and pads on hyperopia amblyopia of children / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To evaluate the therapeutic effects of the fine sight training with the smartphones and pads on hyperopia amblyopia of children.METHODS:One hundred and twenty children (120 eyes) with hyperopia amblyopia were randomly divided into two groups in this prospective study.All the children in these two groups received the basic treatments of spectacle correction,penalization therapy and amblyopia trainings.The treatments of red-light blinking and grating as well as traditional fine sight training were used for the children in the control group.However,the smartphones and pads were applied instead of the traditional performances for the fine sight training in the experimental group.Best corrected visual acuity of every child was tested for every 3mo,to observe the time for the visual improvement and efficacy.RESULTS:In comparison with the control group,significant shorter time (80.54 ± 30.87d,P＜ 0.05) for promoted one line of LogMAR visual acuity and average treatment time (15.34±7.24mo,P＜0.05) were harvested in the experimental group.The efficacy in the experimental group was significantly higher than that in the control group (Z=-2.37,P=0.02).CONCLUSION:The fine sight training with the smartphones and pads can improve vison faster than traditional methods and decrease the time of therapy in children with hyperopia amblyopia,thus providing a new strategy for the treatment of hyperopia amblyopia.

Comparison of visual acuity of the patients on the first day after sub-Bowman keratomileusis or laser in situ keratomileusis.

AIM: To compare recovery of the visual acuity in patients one day after sub-Bowman keratomileusis (SBK) or laser in situ keratomileusis (LASIK). METHODS: Data from 5923 eyes in 2968 patients that received LASIK (2755 eyes) or SBK (3168 eyes) were retrospectively analyzed. The eyes were divided into 4 groups according to preoperative spherical equivalent: between -12.00 to -9.00 D, extremely high myopia (n=396, including 192 and 204 in SBK and LASIK groups, respectively); -9.00 to -6.00 D, high myopia (n=1822, including 991 and 831 in SBK and LASIK groups, respectively), -6.00 to -3.00 D, moderate myopia (n=3071, including 1658 and 1413 in SBK and LASIK groups, respectively), and -3.00 to 0.00 D, low myopia (n=634, including 327 and 307 in SBK and LASIK groups, respectively). Uncorrected logMAR visual acuity values of patients were assessed under standard natural light. Analysis of variance was used for comparisons among different groups. RESULTS: Uncorrected visual acuity values were 0.0115±0.1051 and 0.0466±0.1477 at day 1 after operation for patients receiving SBK and LASIK, respectively (P<0.01); visual acuity values of 0.1854±0.1842, 0.0615±0.1326, -0.0033±0.0978, and -0.0164±0.0972 were obtained for patients in the extremely high, high, moderate, and low myopia groups, respectively (P<0.01). In addition, significant differences in visual acuity at day 1 after operation were found between patients receiving SBK and LASIK in each myopia subgroup. CONCLUSION: Compared with LASIK, SBK is safer and more effective, with faster recovery. Therefore, SBK is more likely to be accepted by patients than LASIK for better uncorrected visual acuity the day following operation.

[The influence of Beijing TCM society on the development of TCM in Beijing].

Being a medical institution with the longest history and most influential TCM academic group, Beijing TCM Learned Society had a 3-stage history in Beijing area. in the Republican period of China in the 1920s, it was set up and organized by the imperial physicians and compiled History of Imperial Physicians in the Qing Dynasty and Yi Tong Zheng Mai (Orthodox Medical Heritage). In the 1930s, the number of its members and achievements reach its zenith. It started to publish China Medical Monthly, compiled many TCM books and extended its influence nationwide. In the 1940s, it was renamed China Medicine Research Association, then joined the International Science Organization. After that it held many academic activities and exchanged many valuable articles. These three phases promoted the development of TCM in Beijing in varying degrees.