Observer-based robust high-order fully actuated attitude autopilot design for spinning glide-guided projectiles

This paper investigates the design of an attitude autopilot for a dual-channel controlled spinning glideguided projectile(SGGP),addressing model uncertainties and external disturbances.Based on fixed-time stable theory,a disturbance observer with integral sliding mode and adaptive techniques is proposed to mitigate total disturbance effects,irrespective of initial conditions.By introducing an error integral signal,the dynamics of the SGGP are transformed into two separate second-order fully actuated systems.Subsequently,employing the high-order fully actuated approach and a parametric approach,the nonlinear dynamics of the SGGP are recast into a constant linear closed-loop system,ensuring that the projectile's attitude asymptotically tracks the given goal with the desired eigenstructure.Under the proposed composite control framework,the ultimately uniformly bounded stability of the closed-loop system is rigorously demonstrated via the Lyapunov method.Validation of the effectiveness of the proposed attitude autopilot design is provided through extensive numerical simulations.

Preparation of waterborne polyurethane/β-cyclodextrin composite nanosponge by ion condensation method and its application in removing of dyes from wastewater

Currently,polymer nanosponges have received extensive attention.However,developing new synthetic techniques for novel nanosponges remains a challenge.Furthermore,to date,composite nanosponge adsorbents based on waterborne polyurethane(WPU)andβ-cyclodextrin(β-CD)have not been reported.Herein,a novel green method,ion condensation method,was developed in this study for the preparation of polymer nanosponge adsorbents for efficient removal of dyes from wastewater.Based on the principle of charge repulsion between nanoparticles to maintain emulsion stability,waterborne polyurethane/β-cyclodextrin composite nanosponges(WPU-x,y)were prepared by coagulating the emulsions synthesized from 2,2-dimethylolpropionic acid,polypropylene glycol and hexamethylene diisocyanate as raw materials in a mixture of hydrochloric acid and anhydrous ethanol.The structure and appearance of WPU-x,y were characterized by attenuated total reflectance Fourier transform infrared spectroscopy,thermal gravimetric analyzer,scanning electron microscope and mercury intrusion porosimetry.The adsorption capacity of WPU-x,y was tested by parameters such as cross-linking degree,β-CD dosage,contact time,initial dye concentration and p H value.The study found that WPU-4,4.62 had the best adsorption effect on methylene blue(MB),the maximum removal rate was 93.42%,and the maximum adsorption capacity was 136.03 mg·g^(-1).Moreover,the Sips isotherm and pseudo-second-order-model were suitable for MB adsorption.Therefore,this study provides some perspectives for the fabrication of nanosponge adsorbents.

寻找海外的乌托邦:康有为、梁启超20世纪初年访问美国“天国”之行述论

戊戌变法失败后,康有为、梁启超流亡海外,周游列国,继续探索西方空想社会主义理想和世界大同之道。1903年、1905年,师徒二人先后来到美国伊利诺伊州锡安市的“理想国”。该“理想国”由澳大利亚籍天主教牧师约翰·亚历山大·陶威创建。陶威信奉《旧约圣经》中宣扬的基督教原教旨主义,在锡安市试行平等互利的“社会主义”经济制度,创办合作社,提倡财产公有;政治上鼓吹天赋人权、男女平等,反对种族歧视;生活上实行禁欲主义,严禁饮酒、吸烟、嫖妓、赌博等。这一理想生活模式迅速吸引了大批欧洲移民到来。本文主要依据笔者近期在美国伊利诺伊州锡安市发现的一批从未面世的中、英文档案文献,考察康、梁二人20世纪初年对美国基督教“天国”锡安市两次鲜为人知的访问活动。

Threshold-Based Adaptive Gaussian Mixture Model Integration(TA-GMMI)Algorithm for Mapping Snow Cover in Mountainous Terrain

Snow cover is an important parameter in the fields of computer modeling,engineering technology and energy development.With the extensive growth of novel hardware and software compositions creating smart,cyber physical systems’(CPS)efficient end-to-end workflows.In order to provide accurate snow detection results for the CPS’s terminal,this paper proposed a snow cover detection algorithm based on the unsupervised Gaussian mixture model(GMM)for the FY-4A satellite data.At present,most snow cover detection algorithms mainly utilize the characteristics of the optical spectrum,which is based on the normalized difference snow index(NDSI)with thresholds in different wavebands.These algorithms require a large amount of manually labeled data for statistical analysis to obtain the appropriate thresholds for the study area.Consideration must be given to both the high and low elevations in the study area.It is difficult to extract all snow by a fixed threshold in mountainous and rugged terrains.In this research,we avoid relying on a manual analysis for different elevations.Therefore,an algorithm based on the GMM is proposed,integrating the threshold-based algorithm and the GMM.First,the threshold-based algorithm with transferred thresholds from other satellites’analysis results are used to coarsely classify the surface objects.These results are then used to initialize the parameters of the GMM.Finally,the parameters of that model are updated by an expectation-maximum(EM)iteration algorithm,and the final results are outputted when the iterative conditions end.The results show that this algorithm can adjust itself to mountainous terrain with different elevations,and exhibits a better performance than the threshold-based algorithm.Compared with orbit satellites’snow products,the accuracy of the algorithm used for FY-4A is improved by nearly 2%,and the snow detection rate is increased by nearly 6%.Moreover,compared with microwave sensors’snow products,the accuracy is increased by nearly 3%.The validation results show that the proposed algorithm can be adapted to a complex terrain environment in mountainous areas and exhibits good performance under a transferred threshold without manually assigned labels.

Interactions between ShPP2-1, an F-box family gene, and ACR11A regulate cold toleranee of tomato

There is a critical need to identify germplasm resources and genes that promote cold tolerance of tomato because global tomato production is threatened by cold stress.We found that the expression of an F-box gene family member named ShPP2-1 from Solanum habrochaites is cold inducible and studied its contribution to cold tolerance.Overexpression of ShPP2-1 in cultivated tomato(AC)reduced cold tolerance by intensifying damage to cell membranes.To explore the underlying molecular mechanism,we conducted a yeast two-hybrid library screen and found that a protein containing ACT domain repeats named ACR11A interacts with PP2-1.Overexpression of SIACR11A in AC enhanced the cold tolerance of seedlings and germinating seeds.Cold tolerance decreased in tomato plants that overexpressed both of these genes.Additionally,we performed seed germination experiments in the cold with 177 tomato accessions and identified two alleles of SlACR11A that differ in one single-nucleotide polymorphism.We found that one of these alleles,SlACR11A G,is significantly enriched in cold-tolerant tomato plants.Taken together,our fi ndings indicate that the combination of low expression levels of PP2-1 and high expression levels of ACR11A can promote cold tolerance.These genes may therefore serve as direct targets for both genetic engineering and improvement projects that aim to enhance the cold tolerance of tomato.

Composite structure Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG ceramics with high color spatial uniformity for white laser lighting

Composite ceramic phosphor(CCP)is a candidate light-conversion material to obtain the high-quality laser lighting source.Phosphors based on the transmissive configuration model could not simultaneously meet the requirements of angular color uniformity and high thermal stability.In this study,a novel composite structure ceramic was designed,including Al_(2)O_(3)-YAG:Ce/YAG layered ceramic with a size of 1 mm×1 mm for lighting,and Al_(2)O_(3) ceramic(φ=16.0 mm)was used as the wrapping material due to its outstanding thermal stability.The prepared ceramics exhibited excellent thermal performance and no yellow ring phenomenon.Through this design,we achieved the match of the intensity distribution of the blue and yellow lights,resulting in a high angular color uniformity of 0.9 with a view angle of±80°.All ceramics showed no luminous saturation phenomenon,even the laser power density was increased up to 47.51 W/mm^(2).A high-brightness white-light source with a luminous flux of 618 lm,a luminous efficiency of 126 lm/W,a CCT of 6615 K,and a CRI of 69.9 was obtained in the transmissive configuration.In particular,the surface temperature of the ceramic was as low as 74.1℃ under a high laser radiation(47.51 W/mm^(2)).These results indicate that Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG composite structure ceramic is a promising luminescent material in the high-power laser lighting applications.

Establishment of green graphite industry:Graphite from biomass and its various applications

Resource-and energy-efficient biomass exploitation for green graphite production is one of the most effective strategies for satisfying graphite demand while minimizing energy consumption and carbon emissions.This study investigated green graphite production from biomass waste and its applications to establish a green graphite industry.Biomass pyrolysis and catalytic graphitization of biochar were studied first to produce green graphite.The optimized green graphite exhibited a reversible capacity of 264 mA h/g and 97%capacity retention over 100 cycles in a half-cell.Green graphite electrodes with a resistivity lower than 5μΩm were fabricated by using organic fraction bio-oil as a green binder.Other green graphite applications,including printing,conductive printing,pencils,and refractories,were also achieved.The overall process of graphite anode and electrode synthesis from biomass waste and short-rotation energy crops was modeled.Approx.95 kg of battery graphite or 109 kg of metallurgical graphite electrodes can be produced per ton of biomass with low primary energy consumption and carbon footprint.Prominently,the modeling result and life cycle assessment demonstrated that,for the production of battery graphite from biomass waste,net-negative-CO_(2)emissions(−0.57 kg CO_(2)-eq/kg graphite powders)with net-negative-primary energy consumption(−28.31 MJ/kg graphite powders)was achieved.

Ultrathin salt-free polymer-in-ceramic electrolyte for solid-state sodium batteries

The practical energy density of solid-state batteries remains limited,partly because of the lack of a general method to fabricate thin membranes for solid-state electrolytes with high ionic conductivity and low area-specific resistance(ASR).Herein,we use an ultrahigh concentration of a ceramic ion conductor(Na_(3)SbS_(4))to build an ionconduction“highway”,and a polymer(polyethylene oxide,2 wt%)as a flexible host to prepare a polymer-inceramic ion-conducting membrane of approximately 40μm.Without the use of any salt(e.g.,NaPF_(6)),the resulting membrane exhibits a threefold increase in electronic ASR and a twofold decrease in ionic ASR compared with a pure ceramic counterpart.The activation energy for sodium-ion transport is only 190 meV in the membrane,similar to that in pure ceramic,suggesting ion transport predominantly occurs through a percolated network of ion-conducting ceramic particles.The salt-free design also provides an opportunity to suppress dendritic metal electrodeposits,according to a recently refined chemomechanical model of metal deposition.Our work suggests that salt is not always necessary in composite solid-state electrolytes,which broadens the choice of polymers to allow the optimization of other desired attributes,such as mechanical strength,chemical/electrochemical stability,and cost.