Fractional Gradient Descent RBFNN for Active Fault-Tolerant Control of Plant Protection UAVs

With the increasing prevalence of high-order systems in engineering applications, these systems often exhibitsignificant disturbances and can be challenging to model accurately. As a result, the active disturbance rejectioncontroller (ADRC) has been widely applied in various fields. However, in controlling plant protection unmannedaerial vehicles (UAVs), which are typically large and subject to significant disturbances, load disturbances andthe possibility of multiple actuator faults during pesticide spraying pose significant challenges. To address theseissues, this paper proposes a novel fault-tolerant control method that combines a radial basis function neuralnetwork (RBFNN) with a second-order ADRC and leverages a fractional gradient descent (FGD) algorithm.We integrate the plant protection UAV model’s uncertain parameters, load disturbance parameters, and actuatorfault parameters and utilize the RBFNN for system parameter identification. The resulting ADRC exhibits loaddisturbance suppression and fault tolerance capabilities, and our proposed active fault-tolerant control law hasLyapunov stability implications. Experimental results obtained using a multi-rotor fault-tolerant test platformdemonstrate that the proposed method outperforms other control strategies regarding load disturbance suppressionand fault-tolerant performance.

Changes of coastline and tidal flat and its implication for ecological protection under human activities: Take China’s Bohai Bay as an example

The change processes and trends of shoreline and tidal flat forced by human activities are essential issues for the sustainability of coastal area,which is also of great significance for understanding coastal ecological environment changes and even global changes.Based on field measurements,combined with Linear Regression(LR)model and Inverse Distance Weighing(IDW)method,this paper presents detailed analysis on the change history and trend of the shoreline and tidal flat in Bohai Bay.The shoreline faces a high erosion chance under the action of natural factors,while the tidal flat faces a different erosion and deposition patterns in Bohai Bay due to the impact of human activities.The implication of change rule for ecological protection and recovery is also discussed.Measures should be taken to protect the coastal ecological environment.The models used in this paper show a high correlation coefficient between observed and modeling data,which means that this method can be used to predict the changing trend of shoreline and tidal flat.The research results of present study can provide scientific supports for future coastal protection and management.

Temperature‑Arousing Self‑Powered Fire Warning E‑Textile Based on p-n Segment Coaxial Aerogel Fibers for Active Fire Protection in Firefighting Clothing

Firefighting protective clothing is a crucial protective equipment for firefighters to minimize skin burn and ensure safety firefighting operation and rescue mission.A recent increasing concern is to develop self-powered fire warning materials that can be incorporated into the firefighting clothing to achieve active fire protection for firefighters before the protective clothing catches fire on fireground.However,it is still a challenge to facilely design and manufacture thermoelectric(TE)textile(TET)-based fire warning electronics with dynamic surface conformability and breathability.Here,we develop an alternate coaxial wet-spinning strategy to continuously produce alternating p/n-type TE aerogel fibers involving n-type Ti_(3)C_(2)T_(x)MXene and p-type MXene/SWCNT-COOH as core materials,and tough aramid nanofiber as protective shell,which simultaneously ensure the flexibility and high-efficiency TE power generation.With such alternating p/n-type TE fibers,TET-based self-powered fire warning sensors with high mechanical stability and wearability are successfully fabricated through stitching the alternating p-n segment TE fibers into aramid fabric.The results indicate that TET-based fire warning electronics containing 50 p-n pairs produce the open-circuit voltage of 7.5 mV with a power density of 119.79 nW cm-2 at a temperature difference of 300℃.The output voltage signal is then calculated as corresponding surface temperature of firefighting clothing based on a linear relationship between TE voltage and temperature.The fire alarm response time and flame-retardant properties are further displayed.Such self-powered fire warning electronics are true textiles that offer breathability and compatibility with body movement,demonstrating their potential application in firefighting clothing.

Active corrosion protection of phosphate loaded PEO/LDHs composite coatings:SIET study

This work produced a Mg Al-layered double hydroxide by hydrothermal treatment of a plasma electrolytic oxidation(PEO) coating on magnesium alloy AZ31 in an phosphate electrolyte, followed by an ion-exchange reaction in 0.1 M phosphate solution. The coated specimens were scratched. Characterization, including utilization of the localized technique SIET, measured the pH and p Mg distributions and optical morphologies around the artificial defects during immersion in 0.05 M NaCl solution. In contrast with phosphate loaded PEO/LDHs, a stronger alkalinization area(with pH 11.4~12.3) appeared in the passive PEO specimens. Due to formation of insoluble Mg(OH)_(2) products, the p Mg map showed depletion of Mg^(2+) in this high p H area. Combined with optical morphologies and SEM images, the better self-healing ability toward defects for phosphate loaded PEO/LDHs was confirmed.

An Active Triggered Surge Protective Gap

A triggered surge protective device is designed and its discharge characteristics axe studied. The experimental results show that the triggered surge protective device has excellent surge protective characteristics. When the gap distance is 5 mm, p. d is 90 Pa.mm and without an active energy trigger circuit, the DC breakdown voltage of the triggered surge protective device is 2.32 kV and the pulse breakdown voltage is 5.75 kV. Therefore, the pulse voltage ratio, which is defined as the specific value of pulse breakdown voltage and DC breakdown voltage, is 2.48. With a semiconductor ZnO flashover trigger device and an active energy coupling trigger circuit, the pulse breakdown voltage can be reduced to 3.32 kV, the pulse voltage ratio is 1.43 and the response time is less than 100 ns. These results are helpful in laying a theoretical foundation for further studies on triggered surge protective devices.

LDH conversion films for active protection of AZ31 Mg alloy

Zinc aluminium(Zn-Al)and lithium aluminium(Li-Al)–layered double hydroxides(LDH)coatings with incorporated inhibitors(Li-,Mo-and W-based)were successfully synthesized on AZ31 Mg alloy.Zn-Al LDH W and Li-Al LDH Li showed the highest corrosion resistance and were selected for further evaluation.SEM cross-section examination revealed a bi-layer structure composed of an outer part with loose flakes and a denser inner layer.XRD,FTIR,and XPS analysis confirmed the incorporation of the inhibitors.Post-treatments with corrosion inhibitors containing solutions resulted in the selective dissolution of the most external layer of the LDH coating,reducing the surface roughness,hydrophilicity and paint adhesion of the layers.Active corrosion properties were confirmed by SVET evaluation for the Zn-Al LDH W coating.The proposed active corrosion mechanism involves the ion-exchange of aggressive Cl-ions,deposition of hydroxides and competitive adsorption of W-rich corrosion inhibitors.

Screening on the Pharmacodynemic Active Parts of Protecting Liver of Peristrope japonica (thunb.)Bremek

The pharmacodynamic active parts of protecting liver of Peristrope japonica (thunb.)Bremek were identified. Rat acute liver injury model was induced by D-galactosamine (D-GlaN). The active parts were identified on the whole extraction and 4 fractions. The results showed that the pharmacodynamic active parts of Peristrope japonica were the n-BuOH fraction.

Seismic protection of frame structures via semi-active control:modeling and implementation issues

Theoretical and practical issues concerning the multi-faceted task of mitigating the latero-torsional seismic response of a prototypal frame structure with asymmetric mass distribution are approached, Chevron braces with embedded magnetorheological dampers acting on the interstory drift are used to ensure additional energy dissipation. The semi-active control strategy employed to govern the modification of the damper characteristics via feedback is based on the selection of optimal forces according to a H2/LQG criterion, with respect to which the actual forces are regulated by a clipped-optimal logic. A dynamic observer is used to estimate the state through a non-collocated placement of the acceleration sensors. Several aspects to be addressed throughout the complex process including the design, modelization, and implementation phases of semi-active protection systems are discussed. Finally, experimental results obtained to mitigate the motion induced by ground excitation in a large-scale laboratory prototype, simulating the seismic response of a two-story building, are summarized.

Inhibition of Micro RNA 219 Expression Protects Synaptic Plasticity via Activating NMDAR1, Ca MKIIγ,and p-CREB after Microwave Radiation

In recent decades,the potential health hazards of microwave exposure have been attracting increasing attention.Our previous studies have demonstrated that microwave exposure impaired learning and memory in experimental animal models[1,2].

Does investor protection affect the choice of earnings management methods through real activity manipulation and accrual manipulation？ Asian comparison

This paper examines systematic differences in earnings management through real activity manipulation and accrual manipulation across 7 Asia countries. The study proposes arguments that in economies with high investor protection, managers prefer to manage earnings through real activity manipulation rather than through accrual manipulation because accrual manipulation is more likely to draw auditors or regulators scrutiny than real decisions about pricing and production. The study findings are consistent with prediction. Despite being in economies with high investor protection, managers still have bigger discretion in managing earnings through real activities rather than accrual manipulation.

A Novel Method for the Protection and Activation of Histidine

The yield and purity of synthetic peptides were greatly related to the amino acid protection and activation during the synthesis process. Therefore, the amino acid protection and activation are the most important steps in peptide synthesis. By using tetrahydrofuran as the solvent, 9-fluorenylmethoxycarbonyl as protection group, 2-(7-azobenzotri- azol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HATU) as condensation reagent an amino protected histidine ester was given. In this article a novel synthesis method for N-(9- fluorenylmethoxycarbonyl)-histidine active ester was established. The reaction conditions for preparing this active ester were optimized. The experimental results indicated that solvents and active reagents had remarkable effects on the yield of active ester. The best conditions for preparing the active ester was a ratio of n (Fmoc-His-OH): n (HATU) = 1:1.2 with THF used as the solvent at room temperature. The yield of the final product was about 80% with a purity of over 85%. This simple method would provide fundamentals for the synthesis of other protected amino acid active esters.

Magnetite nanoparticles coat around activated -alumina spheres: A case of novel protection of moisture-sensitive materials against hydration

Protection of various materials against hydration is of continuing interest to chemists and material scientists. We report on stabilization of porous surface of activated -alumina spheres (AAS) against hydration by an adhesive coat of nano-magnetite particles. The nano-Fe3O4-coated AAS were prepared in the ultrasound-agitated suspension of magnetite nanoparticles in heptane and were characterized by using X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET surface area analysis and X-ray photoelectron spectroscopy (XPS). It is deduced that nanoparticle-alumina bonding interaction in non-polar organic solvent is enhanced by van der Waals attractive forces and that sonication induces changes in alumina morphology only in regions of contact between alumina and magnetite nanoparticles. The coated AAS submerged in still water avoid hydration and remain permeable by small gaseous (N2) molecules, while those soaked in moving water lose part of their coat and undergo hydration. The pristine and the coated AAS were briefly compared for their ability to degrade model antibiotics by using LC-MS analysis. It is confirmed that the degradation of trimethoprim is more efficient on the coated AAS. Our results are challenging for further research of Coulombic interactions between nano-particles and appropriate solid supports.

多肽APS体外抗病原真菌活性及其抗菌机理初探

目的 探讨抗菌肽 APS的体外抗病原真菌的活性及可能的抗菌机理。方法 微量稀释法测定 APS对不同真菌的最低抑菌浓度 (MIC)及最低杀菌浓度 (MBC) ,并检测 APS对脂质平面膜电学性质的影响。结果 除过烟曲霉菌外 ,APS对其它受试病原真菌有较低的 MIC及 MBC。同时 ,经 APS作用后 ,脂质平面膜上形成跨膜电流。结论 APS对多种常见病原真菌均有较强的抑制和杀灭作用。APS抗真菌的可能机制是在膜上持续形成孔道(pores) ,破坏了膜的完整性 ,引起细胞内容物的外流 。

APS星敏感器探测灵敏度研究

从噪声中信号的检测理论着手,推导了恒星信号在有源像元传感器(APS)像面的响应电子数的表示方法,介绍了APS的主要噪声及噪声模型计算,得出了ASP星敏感器的信噪比,并用信噪比阈值推导出APS星敏感器的探测灵敏度模型。通过对典型APS IBIS5的实例计算,得出在常规光学系统设计参数下,当信噪比阈值为8.1,探测概率为99.9%时,探测灵敏度可达到6.5星等。

全光网络中的APS协议及其实现

本文分析了 APS协议在 SDH中与在全光网络中的区别 ,提出了描述和实现 APS协议的一种新的方法。利用这种方法来表述和实现协议简单、而又完善 ,并且非常利于系统协议的升级。

基于APS的SDH自愈环网中的同步策略探讨

时钟同步是数字设备协调无误运行的前提条件。文章针对目前广泛应用的SDH自愈环系统的同步问题进行了较细致的探讨，并提出了在复用段倒换环中将APS协议与同步状态信息的实现相结合的新观卢、，拓开了同步问题的解决空间。

OTN故障监测与APS信令传递机制

生存性是光传送网(OTN)的一个重要研究课题,文章介绍了OTN数字包封帧结构中用于故障监测和保护倒换的字节安排;以基于ODUk的OTN环网保护为例,重点分析了在OTN环网保护中近侧倒换和远侧倒换时的APS信令传递机制.

活性碳负载纳米金属氧化物对AP热分解的催化性能

采用水热法制备了两种纳米金属氧化物(纳米CuO和纳米Fe_(2)O_(3)颗粒),将纳米CuO和纳米Fe_(2)O_(3)负载在活性碳上,制备成CuO@C、Fe_(2)O_(3)@C复合材料,并将其作为催化剂与高氯酸铵(AP)混合制备成混合物样品AP/CuO、AP/CuO@C、AP/Fe_(2)O_(3)、AP/Fe_(2)O_(3)@C;通过扫描电子显微镜(SEM)、差示扫描量热仪(DSC)、热重-微分热重分析(TG-DTG)和热重-红外光谱(TG-FTIR)联用等技术研究了4种催化剂对AP热分解的催化机理及分解动力学特性。结果表明,4种催化剂均将AP的两步分解反应催化为单放热峰,在5 K/min升温速率下,AP的分解峰温较纯AP分别提前90.1、73.4、65.4和69℃;AP/CuO@C分解主要气相产物有HCl、CO_(2)、N_(2)O、HNO_(3)和NO_(2),其中NO_(2)含量最高;AP/Fe_(2)O_(3)@C分解主要气相产物中CO_(2)含量显著提升,NO_(2)含量稍有降低。