Receding horizon control for multiple UAV formation flight based on modified brain storm optimization

Formation flight for unmanned aerial vehicles (UAVs) is a rather complicated global optimum problem. In the global optimum problem, the complex relationship between the controller parameters and the performance index, and the different kinds of constrains under complex combat field environment are taken into account. Brain storm optimization (BSO) is a brand-new swarm intelligence optimization algorithm inspired by a human being’s behavior of brainstorming. In this paper, in allusion to the drawbacks that the basic BSO algorithm traps into local optimum easily and has a slow convergent speed, some novel designs are proposed to enhance the performance of the optimization algorithm. The modified BSO is applied to solve the optimization problem based on the nonlinear Receding horizon control (RHC) mode of UAVs to seek the RHC control parameters for UAV formation flight. Series of comparative experimental results are presented to show the feasibility, validity, and superiority of our proposed method.     

Amphiphilic Schiff base organogels: metal-ion-mediated chiral twists and chiral recognition

New amphiphilic gelators that contained both Schiff base and L-glutamide moieties, abbreviated as o-SLG and p-SLG, were synthesized and their self-assembly in various organic solvents in the absence and presence of metal ions was investigated. Gelation test revealed that o-SLG formed a thermotropic gel in many organic solvents, whilst p-SLG did not. When metal ions, such as Cu(2+), Zn(2+), Mg(2+), Ni(2+), were added, different behaviors were observed. The addition of Cu(2+) induced p-SLG to from an organogel. In the case of o-SLG, the addition of Cu(2+) and Mg(2+) ions maintained the gelating ability of the compound, whilst Zn(2+) and Ni(2+) ions destroyed the gel. In addition, the introduction of Cu(2+) ions caused the nanofiber gel to perform a chiral twist, whilst the Mg(2+) ions enhanced the fluorescence of the gel. More interestingly, the Mg(2+)-ion-mediated organogel showed differences in the fluorescence quenching by D- and L-tartaric acid, thus showing a chiral recognition ability.     

Geissoschizine methyl ether, a corynanthean-type indole alkaloid from Uncaria rhynchophylla as a potential acetylcholinesterase inhibitor

Geissoschizine methyl ether (1), a newly discovered strong acetylcholinesterase (AChE) inhibitor, along with six weakly active alkaloids, vallesiachotamine (2), hisuteine (3), hirsutine (4), isorhynchophylline (5), cisocorynoxeine (6) and corynoxeine (7) have been isolated from Uncaria rhynchophylla. Geissoschizine methyl ether (1) inhibited 50% of AChE activity at concentrations of 3.7?±?0.3?μg?mL(-1) while the IC(50) value of physostigmine as a standard was 0.013?±?0.002?μg?mL(-1). The mode of AChE inhibition by 1 was reversible and non-competitive. In addition, molecular modelling was performed to explore the binding mode of inhibitor 1 at the active site of AChE.     

Methoxypoly(ethylene glycol)‐block‐Poly(L‐glutamic acid)‐Loaded Cisplatin and a Combination With iRGD for the Treatment of Non‐Small‐Cell Lung Cancers

CDDP is loaded into methoxypoly(ethylene glycol)‐block‐poly(L ‐glutamic acid) (mPEG‐b‐PLG), and a combination with iRGD is applied for NSCLC chemotherapy. The CDDP‐loaded micelles show sustained cisplatin release in PBS, dose‐ and time‐dependent inhibition to HeLa and A549 cell proliferation, and no apparent hemolysis activities. In in vivo studies using subcutaneous NSCLC xenograft models (A549), both free CDDP and CDDP‐loaded micelles show an evident anti‐tumor effect. However, the toxicity of CDDP is significantly reduced in the cases of CDDP‐loaded micelles and co‐administration with iRGD, and the survival time is prolonged by over 30%. Therefore, mPEG‐b‐PLG‐loaded cisplatin and the combination with iRGD provides a promising new therapy for NSCLC.

     

稀土在机动车尾气催化净化中的应用与研究进展

随着我国机动车尾气排放法规日趋严格,对机动车尾气净化催化剂性能提出了更高的要求.稀土元素由于独特的4f电子层结构和储放氧性能等特性,在机动车尾气催化剂中得到广泛应用.本文综述了稀土元素在机动车尾气催化剂中的应用及相关机理研究现状,并依据京V排放法规要求探讨了最新排放限值对尾气净化催化剂性能的要求,分析了稀土在开发高性能催化剂中的作用,并对稀土在机动车尾气净化催化剂中的应用前景进行了展望.     

Soluble and Green‐light‐emitting Oligo(9‐fluorenylideneacetic acid): Electrosynthesis and Characterization

A novel semiconducting oligo(9‐fluorenylideneacetic acid) (OFYA) with good redox activity and stability was successfully electrosynthesized by direct anodic oxidation of 9‐fluorenylideneacetic acid (FYA) in CH₂Cl₂ containing boron trifluoride diethyl etherate (BFEE) as the supporting electrolyte. The as‐formed OFYA film was readily soluble in dimethyl sulfoxide and tetrahydrofuran, and partly soluble in water, alcohol, acetonitrile and acetone. FT‐IR and ¹H NMR spectra, together with computational results proved that FYA was probably polymerized through the coupling at C(2) and C(7) positions. Further, OFYA was a typical green light‐emitter with maximal emission at 555 nm and its fluorescence quantum yield was distinctly improved in comparison with that of the monomer. The oligomer was also studied by UV‐vis spectroscopy, MALDL‐TOF mass spectrometry, and thermal analysis, respectively.     

Effect of aluminum modification on catalytic properties of PtSn-based catalysts supported on SBA-15 for propane dehydrogenation

The catalytic properties of PtSn-based catalysts supported on siliceous SBA-15 and Al-modified SBA-15, such as Al-incorporated SBA-15 (AlSBA-15) and alumina-modified SBA-15 (Al2O3/SBA-15), for propane dehydrogenation were investigated. Al2O3/SBA-15 was prepared either by an impregnation method using aluminum nitrate aqueous solution, or by the treatment of SBA-15 with a Al(OC3H7)3 solution in anhydrous toluene. N2-physisorption, FT-IR spectroscopy, solid-state 27Al MAS NMR spectroscopy, hydrogen chemisorption, XRF, NH3 temperature-programmed desorption, X-ray photoelectron spectroscopy and TPO were used to characterize these samples. Among these catalysts, the PtSn-based catalyst supported on Al2O3/SBA-15, which was grafted with Al(OC3H7)3, exhibited the best catalytic performance in terms of activity and stability The possible reason was due to the high Pt metal dispersion and/or the strong interactions among Pt, Sn, and the support.     

Oxime radical promoted dioxygenation, oxyamination, and diamination of alkenes: synthesis of isoxazolines and cyclic nitrones

Up the tempo: The intramolecular addition of oxime radicals to C?C bonds was achieved by using DEAD and TEMPO to give 4,5-dihydroisoxazoles as a result of a C?O bond-forming, 5-exo-trig cyclization. γ,δ-Unsaturated ketoximes also reacted to afford cyclic nitrones through C?N bond formation. The reactions offer a metal-free approach for the vicinal difunctionalization of unactivated alkenes.     

Theoretical Insight into the Origin of Large Stokes Shift and Photophysical Properties of Anilido‐Pyridine Boron Difluoride Dyes

The geometric and electronic structures and photophysical properties of anilido‐pyridine boron difluoride dyes 1 – 4 , a series of scarce 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) derivatives with large Stokes shift, are investigated by employing density functional theory (DFT) and time‐dependent DFT (TD‐DFT) calculations to shed light on the origin of their large Stokes shifts. To this end, a suitable functional is first determined based on functional tests and a recently proposed index—the charge‐transfer distance. It is found that PBE0 provides satisfactory overall results. An in‐depth insight into Huang–Rhys (HR) factors, Wiberg bond indices, and transition density matrices is provided to scrutinize the geometric distortions and the character of excited states pertaining to absorption and emission. The results show that the pronounced geometric distortion due to the rotation of unlocked phenyl groups and intramolecular charge transfer are responsible for the large Stokes shift of 1 and 2 , while 3 shows a relatively blue‐shifted emission wavelength due to its mild geometric distortion upon photoemission, although it has a comparable energy gap to 1 . Finally, compound 4 , which is designed to realize the rare red emission in BODIPY derivatives, shows desirable and expected properties, such as high Stokes shift (4847 cm^?1), red emission at 660 nm, and reasonable fluorescence efficiency. These properties give it great potential as an ideal emitter in organic light‐emitting diodes. The theoretical results could complement and assist in the development of BODIPY‐based dyes with both large Stokes shift and high quantum efficiency.