Maximum Correntropy Criterion-Based UKF for Loosely Coupling INS and UWB in Indoor Localization

Indoor positioning is a key technology in today’s intelligent environments,and it plays a crucial role in many application areas.This paper proposed an unscented Kalman filter(UKF)based on the maximum correntropy criterion(MCC)instead of the minimummean square error criterion(MMSE).This innovative approach is applied to the loose coupling of the Inertial Navigation System(INS)and Ultra-Wideband(UWB).By introducing the maximum correntropy criterion,the MCCUKF algorithm dynamically adjusts the covariance matrices of the system noise and the measurement noise,thus enhancing its adaptability to diverse environmental localization requirements.Particularly in the presence of non-Gaussian noise,especially heavy-tailed noise,the MCCUKF exhibits superior accuracy and robustness compared to the traditional UKF.The method initially generates an estimate of the predicted state and covariance matrix through the unscented transform(UT)and then recharacterizes the measurement information using a nonlinear regression method at the cost of theMCC.Subsequently,the state and covariance matrices of the filter are updated by employing the unscented transformation on the measurement equations.Moreover,to mitigate the influence of non-line-of-sight(NLOS)errors positioning accuracy,this paper proposes a k-medoid clustering algorithm based on bisection k-means(Bikmeans).This algorithm preprocesses the UWB distance measurements to yield a more precise position estimation.Simulation results demonstrate that MCCUKF is robust to the uncertainty of UWB and realizes stable integration of INS and UWB systems.

Nitrogen-Doped Graphene Foam as a Metal-Free Catalyst for Reduction Reactions under a High Gravity Field

Herein,we report on the effect of a high gravity field on metal-free catalytic reduction,taking the nitrobenzene(NB)reduction and methylene blue(MB)degradation as model reactions in a highgravity rotating tube reactor packed with three-dimensional(3D)nitrogen-doped graphene foam(NGF)as a metal-free catalyst.The apparent rate constant(kapp)of the metal-free catalytic reduction of NB in the rotating tube reactor under a high gravity level of 6484g(g=9.81 m s-2)was six times greater than that in a conventional stirred reactor(STR)under gravity.Computational fluid dynamics(CFD)simulations indicated that the improvement of the catalytic efficiency was attributed to the much higher turbulent kinetic energy and faster surface renewal rate in the high-gravity tube reactor in comparison w让h those in a conventional STR.The structure of the 3D metal-free catalysts was stable during the reaction process under a high gravity field,as confirmed by X-ray photoelectron spectroscopy(XPS)and Raman spectra.In the other model reaction,the rate of MB degradation also increased as the high gravity level in creased gradually,which aligns with the result for the NB catalytic reduction system.These results demonstrate the potential to use a high-gravity rotating packed tube reactor for the process intensification of metal-free catalytic reduction reactions.

High-gravity-assisted engineering of Ni_(2)P/g-C_(3)N_(4) nanocomposites with enhanced photocatalytic performance

Graphitic carbon nitride(g-C_(3)N_(4)) with transition metal phosphides has been studied extensively as potential photocatalysts for hydrogen evolution.However,in-situ approaches to realize intimate interfacial contacts have rarely been reported.In this study,Ni_(2)P nanoparticlesdecorated g-C_(3)N_(4)photocatalysts were prepared via liquid exfoliation of g-C_(3)N_(4) followed by in-situ loading of Ni_(2)P nanoparticles in a rotating packed bed(RPB) reactor.The optimized Ni_(2)P/g-C_(3)N_(4) exhibits high performance in visible-light-driven(λ > 420 nm) hydrogen evolution(~561 μmol g-1h-1),which is 103 times higher than that of pristine g-C_(3)N_(4).The superior photocatalytic performance and durability originate from the robust interfacial structure.Therefore,a Z-scheme route with enhanced transfer of photoinduced electron was proposed,and Ni_(2)P/gC_(3)N_(4) composites with smaller bandgaps than those of g-C_(3)N_(4) were realized.Due to the intensified mass transfer and mixing of RPB reactor,the adsorption and nucleation processes of Ni_(2)P on g-C_(3)N_(4) were enhanced,enabling scalable solar light-driven H_(2) production.

Regulation of Oxygen Activity by Lattice Confinement over Ni_(x)Mg_(1-x)O Catalysts for Renewable Hydrogen Production

The chemical looping steam reforming(CLSR)of bioethanol is an energy-efficient and carbon-neutral approach of hydrogen production.This paper describes the use of a Ni_(x)Mg_(1-x)O solid solution as the oxy-gen carrier(OC)in the CLSR of bioethanol.Due to the regulation effect of Mg^(2+)in Ni_(x)Mg_(1-x)O,a three-stage reaction mechanism of the CLSR process is proposed.The surface oxygen of Ni_(x)Mg_(1-x)O initially causes complete oxidation of the ethanol.Subsequently,H_(2)O and bulk oxygen confined by Mg^(2+)react with etha-nol to form CH_(3)COO^(*)followed by H_(2) over partially reduced Ni_(x)Mg_(1-x)O.Once the bulk oxygen is con-sumed,the ethanol steam reforming process is promoted by the metallic nickel in the stage Ⅲ.As a result,Ni_(0.4)Mg_(0.6)O exhibits a high H_(2) selectivity(4.72 mol H_(2) per mole ethanol)with a low steam-to-carbon molar ratio of 1,and remains stable over 30 CLSR cycles.The design of this solid-solution OC pro-vides a versatile strategy for manipulating the chemical looping process.

Synthesis of Silver Sulf ide Quantum Dots Via the Liquid–Liquid Interface Reaction in a Rotating Packed Bed Reactor

We developed the high-gravity coupled liquid-liquid interface reaction technique on the basis of the rotating packed bed(RPB)reactor for the continuous and ultrafast synthesis of silver sulfide(Ag2S)quantum dots(QDs)with near-infrared(NIR)luminescence.The formation of Ag2S QDs occurs at the interface of microdroplets,and the average size of Ag2S QDs was 4.5 nm with a narrow size distribution.Ag2S QDs can disperse well in various organic solvents and exhibit NIR luminescence with a peak wavelength at 1270 nm under 980-nm laser excitation.The mechanism of the process intensification was revealed by both the computational fluid dynamics simulation and fluorescence imaging,and the mechanism is attributed to the small and uniform droplet formation in the RPB reactor.This study provides a novel approach for the continuous and ultrafast synthesis of NIR Ag2S QDs for potential scale-up.

Cartilage-inspired self-assembly glycopeptide hydrogels for cartilage regeneration via ROS scavenging

Cartilage injury represents a frequent dilemma in clinical practice owing to its inherently limited self-renewal capacity.Biomimetic strategy-based engineered biomaterial,capable of coordinated regulation for cellular and microenvironmental crosstalk,provides an adequate avenue to boost cartilage regeneration.The level of oxidative stress in microenvironments is verified to be vital for tissue regeneration,yet it is often overlooked in engineered biomaterials for cartilage regeneration.Herein,inspired by natural cartilage architecture,a fibril-network glycopeptide hydrogel(Nap-FFGRGD@FU),composed of marine-derived polysaccharide fucoidan(FU)and naphthalenephenylalanine-phenylalanine-glycine-arginine-glycine-aspartic peptide(Nap-FFGRGD),was presented through a simple supramolecular self-assembly approach.The Nap-FFGRGD@FU hydrogels exhibit a native cartilage-like architecture,characterized by interwoven collagen fibers and attached proteoglycans.Beyond structural simulation,fucoidan-exerted robust biological effects and Arg-Gly-Asp(RGD)sequence-provided cell attachment sites realized functional reinforcement,synergistically promoted extracellular matrix(ECM)production and reactive oxygen species(ROS)elimination,thus contributing to chondrocytes-ECM harmony.In vitro co-culture with glycopeptide hydrogels not only facilitated cartilage ECM anabolic metabolism but also scavenged ROS accumulation in chondrocytes.Mechanistically,the chondro-protective effects induced by glycopeptide hydrogels rely on the activation of endogenous antioxidant pathways associated with nuclear factor erythroid 2-related factor 2(NRF2).In vivo implantation of glycopeptide hydrogels successfully improved the de novo cartilage generation by 1.65-fold,concomitant with coordinately restructured subchondral bone structure.Collectively,our ingeniously crafted bionic glycopeptide hydrogels simultaneously rewired chondrocytes’function by augmenting anabolic metabolism and rebuilt ECM microenvironment via preserving redox equilibrium,holding great potential for cartilage tissue engineering.

Biomimetic melatonin-loaded silk fibroin/GelMA scaffold strengthens cartilage repair through retrieval of mitochondrial functions

Articular cartilage injury induced by collision or trauma is a common sports-related condition that may progress to pain,dysfunction,and secondary osteoarthritis(OA).Limited by self-renewal potential,cartilage regeneration faces a quandary while bio-inspired novel strategies are urgently required.In this study,by a soft freezing method and surface modification technique,a multi-functional silk fibroin(SF)plus gelatin methacrylate(GelMA)scaffold laden with melatonin(MT)was prepared.SF-GelMA@MT scaffold demonstrated enhanced biomechanical characteristics and long-acting melatonin release.In vitro treatment with SF-GelMA@MT induced the synthesis of cartilage extracellular matrix(ECM)components.Mechanistically,sustained release of melatonin yielded robust chondroprotective effects via improving mitochondrial polarization and antioxidant properties.SF-GelMA@MT implantation boosted cartilage renascence in a full-thickness cartilage defect model via mitochondria-associated sirtuins 1(SIRT1)-superoxide dismutase 2(SOD2)signaling pathway in vivo.In summary,this research proposed a welldesigned bionic composite scaffold that promotes cartilage regeneration via mitochondrial function enhancement,which is of tremendous potential for cartilage tissue engineering.

Incorporation of kartogenin and silk fibroin scaffolds promotes rat articular cartilage regeneration through enhancement of antioxidant functions

Treating articular cartilage defects in patients remains a challenging task due to the absence of blood vessels within the cartilage tissue.The regenerative potential is further compromised by an imbalance between anabolism and catabolism,induced by elevated levels of reactive oxygen species.However,the advent of tissue engineering introduces a promising strategy for cartilage regeneration,offering viable solutions such as mechanical support and controlled release of chondrogenic molecules or cytokines.In this study,we developed an antioxidant scaffold by incorporating natural silk fibroin(SF)and kartogenin(KGN)-loaded liposomes(SF-Lipo@KGN).The scaffold demonstrated appropriate pore size,connectivity,and water absorption and the sustained release of KGN was achieved through the encapsulation of liposomes.In vitro experiments revealed that the SF-Lipo@KGN scaffolds exhibited excellent biocompatibility,as evidenced by enhanced cell adhesion,migration,and proliferation of chondrocytes.The SF-Lipo@KGN scaffolds were found to stimulate cartilage matrix synthesis through the activation of the nuclear factor erythroid-2-related factor 2/heme oxygenase-1 antioxidant signaling pathway.In vivo experiments demonstrated the effective promotion of articular cartilage regeneration by the SF-Lipo@KGN scaffolds,which enhanced extracellular matrix anabolism and restored the intrinsic redox homeostasis.Overall,this study successfully developed biomimetic KGN-loaded scaffolds that restore cartilage redox homeostasis,indicating promising prospects for cartilage tissue engineering.