Structural Control Research Articles

A seamless Phase I/II platform design with a time-to-event efficacy endpoint for potential COVID-19 therapies.

In the search for effective treatments for COVID-19, the initial emphasis has been on re-purposed treatments. To maximize the chances of finding successful treatments, novel treatments that have been developed for this disease in particular, are needed. In this article, we describe and evaluate the statistical design of the AGILE platform, an adaptive randomized seamless Phase I/II trial platform that seeks to quickly establish a safe range of doses and investigates treatments for potential efficacy. The bespoke Bayesian design (i) utilizes randomization during dose-finding, (ii) shares control arm information across the platform, and (iii) uses a time-to-event endpoint with a formal testing structure and error control for evaluation of potential efficacy. Both single-agent and combination treatments are considered. We find that the design can identify potential treatments that are safe and efficacious reliably with small to moderate sample sizes.

Defect Chemistry in High-Voltage Cathode Materials for Lithium-Ion Batteries.

High-voltage cathodes (HVCs) have emerged as a paramount role for the next-generation high-energy-density lithium-ion batteries (LIBs). However, the pursuit of HVCs comes with inherent challenges related to defective structures, which significantly impact the electrochemical performance of LIBs. The current obstacle lies in the lack of a comprehensive understanding of defects and their precise effects. This perspective aims to provide insights into defect chemistry for governing HVCs. The classifications, formation mechanisms, and evolution of defects are outlined to explore the intricate relationship between defects and electrochemical behavior. The pressing need for cutting-edge characterization techniques that comprehensively investigate defects across various temporal and spatial scales is emphasized. Building on these fundamental understandings, engineering strategies such as composition tailoring, morphology design, interface modification, and structural control to mitigate or utilize defects are thoroughly discussed for enhanced HVCs performance. These insights are expected to provide vital guidelines for developing high-performance HVCs for next-generation high-energy lithium-ion batteries.

Designs in Bionic Robots: Compared with Conventional Robots

With the advancement in relative technology, robotics is gaining an increasing amount of attention among engineers and researchers as it is a current focus on enabling peoples lives to become more convenient. However, there is another type of robot designed very differently from functional robots like delivery robots and quadrotors that most people are familiar with, bionic robots. This is a kind of robots that gets design inspiration from real animals in nature, from the design of structure to altitudes and mechanisms of motion. How bionic robots are designed, and how the conceptional difference of bionic robots with other robots is reflected on their physical designs are the focuses of this paper. In this paper, four basic types of bionic robots are introduced and 17 existing designs of bio-inspired vehicles are included. 10 bionic aerial vehicles in 3 smaller classifications are compared to 3 conventional aerial vehicles in order to figure out differences in 3 aspects (structure design, sensors, and control method). The results show that bionic robots usually have more degrees of freedom in order to mimic animals attitudes, and are lighter in weight. Typically, bio-inspired aerial vehicles employ different wing systems compared with conventional ones. Additionally, while conventional vehicles favour PID more because of its ease of construction, bionic robots use machine learning techniques. Both types of robots use the same sensors, which is necessary for them to detect their environment. However, their control methods differ due to different purposes.

Improving photoexcited carrier separation through Z-scheme W18O49/BiOBr heterostructure coupling carbon quantum dots for efficient photoelectric response and tetracycline photodegradation

Building Z-scheme heterostructure integrating oxygen vacancies seems to effectively encourage photoexcited charge partition and hence photoelectric response and photocatalytic performance. Here, through the inclusion of carbon quantum dots (CQDs) with W18O49/BiOBr (WB) for enhancing electron exchange and band structure control, we have developed one Z-scheme ternary CQD/W18O49/BiOBr heterostructures (CWB) with intense oxygen vacancies. The optimal CWB heterostructure shows superior photocatalytic and photoelectric response execution. The findings indicate that CWB has higher photocatalytic degradation efficiency of tetracycline hydrochloride (TC) at 97 % compared to WB or W18O49 alone. Additionally, the CWB shows a higher photocurrent density, surpassing WB and W18O49 by 2.5 times and 5.4 times. A potential self-supplied photoelectrochemical-type photodetector utilizing CWB displays relatively quick and stable photoelectric response at 0 V. The improved photo-electric performance are linked to the combined impact of separation and redistribution of charges caused by Z-scheme heterostructure and oxygen vacancies, as well as intensive light absorbance by localized surface plasmon resonance. Our research also validates significance of CQDs as cocatalyst in accelerating the splitting of photo carriers in Z-scheme ternary CWB heterostructures, which will stimulate interest in creating advanced photoactive heterojunction substance with carbon nanomaterials.

Zeolite Crystallization Inside Chemically Recyclable Ordered Nanoporous Co3O4 Scaffold: Precise Replication and Accelerated Crystallization.

The synthesis of mesoporous zeolites has garnered attention with regard to improving their catalytic and adsorption performances. While the hard-templating method provides opportunities to design precisely controlled hierarchical micro- and mesoporous structures, synthesizing mesoporous zeolites without external precipitation requires significant work. This is mainly due to the absence of usable templates other than carbon with hydrophobic surfaces. Herein, it is demonstrated that the Co3O4 template is valuable in preparing mesoporous silicalite-1 and ZSM-5 with a precisely controlled porous structure through hydrothermal synthesis. Unlike conventional carbon templates, the Co3O4 template is relatively hydrophilic, effective in suppressing external precipitation, and is reusable by dissolving in an acidic solution. The crystallization process also differs from that of the carbon template, as the silicate precipitates on a 3D ordered nanoporous Co3O4 scaffold, followed by crystallization and crystal growth. Furthermore, it is unexpectedly observed that the zeolite crystallization is accelerated in the Co3O4 template. The synthetic approach utilizing nanoporous metal oxides opens new doors for the control of the hierarchical structure of zeolites, as well as for the design of metal oxide-zeolite nanocomposite catalysts, due to the potential extensibility of the combination of metal oxides and zeolites.

Numerical and Experimental Study of a Wearable Exo-Glove for Telerehabilitation Application Using Shape Memory Alloy Actuators

Hand paralysis, caused by conditions such as spinal cord injuries, strokes, and arthritis, significantly hinders daily activities. Wearable exo-gloves and telerehabilitation offer effective hand training solutions to aid the recovery process. This study presents the development of lightweight wearable exo-gloves designed for finger telerehabilitation. The prototype uses NiTi shape memory alloy (SMA) actuators to control five fingers. Specialized end effectors target the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints, mimicking human finger tendon actions. A variable structure controller, managed through a web-based Human–Machine Interface (HMI), allows remote adjustments. Thermal behavior, dynamics, and overall performance were modeled in MATLAB Simulink, with experimental validation confirming the model’s efficacy. The phase transformation characteristics of NiTi shape memory wire were studied using the Souza–Auricchio model within COMSOL Multiphysics 6.2 software. Comparing the simulation to trial data showed an average error of 2.76°. The range of motion for the MCP, PIP, and DIP joints was 21°, 65°, and 60.3°, respectively. Additionally, a minimum torque of 0.2 Nm at each finger joint was observed, which is sufficient to overcome resistance and meet the torque requirements. Results demonstrate that integrating SMA actuators with telerehabilitation addresses the need for compact and efficient wearable devices, potentially improving patient outcomes through remote therapy.

Preparation and properties of bio-based PA56/SiO2–NH2 composite nanofiber membranes for high efficiency oil-water separation

With the continuous development of environmental protection and resource recycling demands, the development of bio-based separation membrane materials has increasingly attracted attention. Bio-based polyamide 56 (PA56), exhibiting excellent hydrophilicity, spinnability, and mechanical properties, is expected to complement and replace traditional separation membrane materials. In this study, the electrospinning preparation and structural control of PA56 nanofiber membranes were achieved through the optimization of PA56 content and mixed solvent ratios. The study found that when the PA56 content was 16 wt% and the formic acid to acetone ratio in the mixed solvent was 8:2, the nanofiber diameter distribution was the most uniform. Building on this, amino-functionalized modified silica (SiO2–NH2) nanoparticles were introduced to prepare PA56/SiO2–NH2 composite nanofiber membranes featuring a cobweb-like nanofiber network and micro-nodule structure. The effects of the addition of SiO2–NH2 nanoparticles on the morphology, structure, and properties of the fiber membranes were studied. The results indicate that the control of the mixed solvent ratio and the addition of SiO2–NH2 nanoparticles led to the formation of a cobweb-like nanofiber network and micro-nano nodular structure on the nanofiber surface, enhancing the hydrophilicity of PA56 nanofiber membranes. The M − 3 membrane with a nanoparticle addition amount of 0.8 wt% exhibited high hydrophilicity and underwater superoleophobic properties, achieving efficient separation of stable oil-in-water emulsions with a separation efficiency of 99.8 %. This work provides a new bio-based membrane material and its preparation method for treating oily wastewater using the membrane separation method.

Synthesis and Local Characterization of CoO Nanoparticles in Distinct Phases: Unveiling Polymorphic Structures.

The advancement of functional nanomaterials has become a major focus of recent research, driven by the exceptional properties these materials display compared to their macroscopic (bulk) counterparts. Cobalt oxide nanoparticles (CoO-NPs) stand out primarily for their catalytic and magnetic properties, which can enable a range of technological applications, such as advanced catalysts, drug delivery systems, implants, prosthetics, sensors. However, in addition to the dependence on factors such as size, morphology, and functionalization, the properties of CoO-NPs are significantly influenced by the crystal structure. Therefore, local investigation into the polymorphic structures of CoO at the nanometric scale may provide new insights into the local structural and magnetic characteristics of these systems. In this report, we address the synthesis and local characterization of cobalt oxide (CoO) nanoparticles in the rock-salt cubic fcc-CoO and Wurtzite hpc-CoO phases, obtained through thermal decomposition. We analyze the influence of oleylamine and oleic acid ligands on the structural and morphological control of these systems. The obtained nanoparticles were characterized using conventional techniques such as X-ray diffraction (XRD), transmission electron microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. Local characterization was carried out by the perturbed angular correlation (PAC) nuclear technique using the radioactive tracer 111In(111Cd). Measurements were conducted at 295 and 10 K to investigate possible magnetic phase transitions in these systems. XRD results confirmed the formation of fcc-CoO and hcp-CoO phases. The phase fcc was obtained with the pair of oleylamine and oleic acid ligands, while the phase hcp phase was synthesized using only oleylamine. Additionally, nanoparticles synthesized with oleylamine and oleic acid exhibited better morphological control compared to those produced with only oleylamine. Raman spectroscopy analyses suggest a phase transformation process resulting in Co3O4. PAC results for hyperfine interactions at the 111In(111Cd) probe nucleus, indicate that the hcp-CoO phase shows smaller hyperfine magnetic interactions (B hf = 1 T) compared to the fcc-CoO phase (B hf = 17 T). This suggests the mechanism of superexchange interactions, which are strongly influenced by the Co-O-Co bond angle, which is 110° for the hpc-CoO phase and 180° for the fcc-CoO phase due to the geometries of the systems.

Structural Control of Copper-Based MOF Catalysts for Electroreduction of CO2: A Review

Structural Control of Copper-Based MOF Catalysts for Electroreduction of CO2: A Review

Peptide programming of supramolecular vinylidene fluoride ferroelectric phases.

Ferroelectric structures have spontaneous macroscopic polarization that can be inverted using external electric fields and have potential applications including information storage, energy transduction, ultralow-power nanoelectronics1,2 and biomedical devices3. These functions would benefit from nanoscale control of ferroelectric structure, the ability to switch polarization with lower applied fields (low coercive field) and biocompatibility. Soft ferroelectrics based on poly(vinylidene fluoride) (PVDF)4-6 have a thermodynamically unstable ferroelectric phase in the homopolymer, complex semi-crystalline structures, and high coercive fields. Here we report on ferroelectric materials formed by water-soluble molecules containing only six VDF repeating units covalently conjugated to a tetrapeptide, with the propensity to assemble into the β-sheet structures that are ubiquitous in proteins. This led to the discovery of ribbon-shaped ferroelectric supramolecular assemblies that are thermodynamically stable with their long axes parallel to both the preferred hydrogen-bonding direction of β-sheets and the bistable polar axes of VDF hexamers. Relative to a commonly used ferroelectric copolymer, the biomolecular assemblies exhibit a coercive field that is two orders of magnitude lower, as the result of supramolecular dynamics, and a similar level of remnant polarization, despite having a peptide content of 49 wt%. Furthermore, the Curie temperature of the assemblies is about 40 °C higher than that of a copolymer containing a similar amount of VDF. This supramolecular system was created using a biologically inspired strategy that is attractive in terms of sustainability and that could lead to new functions for soft ferroelectrics.

Study on mechanical response control of metal-ceramic dual phase hybrid lattice structure

Different from the previous trial-and-error and empirical development process of new materials, the failure and deformation of meso-structure of lattice structures are considered as a means to customize the mechanical response in this paper. Based on this, we propose a novel metal-ceramic dual-phase hybrid lattice structure (DPHLS) that exhibits both high peak stress and a prolonged plateau stage in its mechanical response. This design aims to meet the complex mechanical response requirements of impact target materials in hard target penetration research. The DPHLS is composed of a ceramic-based SC plate lattice structure and a metal-based FCC plate lattice structure, allowing for a broad range of mechanical properties control. Besides, by combining the advantages of both ceramic and metal, the DPHLS exhibits seemingly conflicting properties of load-bearing capacity and energy absorption. In the present work, the contribution of failure and deformation behavior to the mechanical response of the structure is deeply analyzed at the mesoscopic level using theoretical analysis and numerical simulation. The quantitative relationship between the geometrical parameters of the structure and the mechanical response is established actively. The results show that the three dimensionless geometric parameters, which characterize the geometry of DPHLS, can effectively regulate its mechanical response. This study not only provides a reliable theoretical basis for the design of mesostructures in DPHLS, but also proposes a novel strategy for the customization of mechanical response.

A force-density framework for flexible multi-body dynamic analysis of clustered tensegrity structures

This paper develops a versatile and effective force-density framework for the flexible multi-body dynamic analysis of clustered tensegrity structures. In this framework, the force density is selected as the basic variable instead of force, and the clustered tensegrity structure is mathematically described in a vector and matrix form, encompassing topology, geometry, material, and force properties. A non-negative variable is defined as an indicator of the member stress state, and a complementary function is constructed to address the discontinuity issues that arise from the unidirectional axial stiffness of cables. Dynamic formulas are established within this force-density framework, with nodal coordinates selected as generalized parameters and formulations constructed in a matrix form. A complementary framework is established as an alternative for solving the dynamic equations, transforming the isolated steps of Newton’s iteration and cable state judgment (slack or tension) into a unified one, bringing more potential for improving solving efficiency. Numerical simulations are carried out to validate the approach, demonstrating that it effectively reveals the dynamic oscillation, tension changes, and cable slack behavior of clustered tensegrity structures during shape control. Comparative studies highlight the advantage of computational efficiency. The method proposed in this paper provides a robust mathematical model for studying clustered tensegrity structures, particularly regarding the shape control of deployable, active, and intelligent structures, aiding in understanding dynamic oscillation, tension changes, and cable slack behavior during their deformation. The methods can also be applied to cable net structures and other prestressed pin-jointed systems.

Supramolecular Reconstruction of Self-Assembling Photosensitizers for Enhanced Photocatalytic Hydrogen Evolution.

Natural photosynthetic systems require spatiotemporal organization to optimize photosensitized reactions and maintain overall efficiency, involving the hierarchical self-assembly of photosynthetic components and their stabilization through synergistic interactions. However, replicating this level of organization is challenging due to the difficulty in efficiently communicating supramolecular nano-assemblies with nanoparticles or biological architectures, owing to their dynamic instability. Herein, we demonstrate that the supramolecular reconstruction of self-assembled amphiphilic rhodamine B nanospheres (RN) through treatment with metal-phenolic coordination complexes results in the formation of a stable hybrid structure. This reconstructed structure enhances electron transfer efficiency, leading to improved photocatalytic performance. Due to the photoluminescence quenching property of RN and its electronic synergy with tannic acid (T) and zirconium (Z), the supramolecular complexes of hybrid nanospheres (RNTxZy) with Pt nanoparticles or a biological workhorse, Shewanella oneidensis MR-1, showed marked improvement in photocatalytic hydrogen production. The supramolecular hybrid particles with a metal-phenolic coordination layer showed 5.6- and 4.0-fold increases, respectively, in the productivities of hydrogen evolution catalyzed by Pt (Pt/RNTxZy) and MR-1 (M/RNTxZy), respectively. These results highlight the potential for further advancements in the structural and photochemical control of supramolecular nanomaterials for energy harvesting and bio-hybrid systems.

Supramolecular Reconstruction of Self‐Assembling Photosensitizers for Enhanced Photocatalytic Hydrogen Evolution

Natural photosynthetic systems require spatiotemporal organization to optimize photosensitized reactions and maintain overall efficiency, involving the hierarchical self‐assembly of photosynthetic components and their stabilization through synergistic interactions. However, replicating this level of organization is challenging due to the difficulty in efficiently communicating supramolecular nano‐assemblies with nanoparticles or biological architectures, owing to their dynamic instability. Herein, we demonstrate that the supramolecular reconstruction of self‐assembled amphiphilic rhodamine B nanospheres (RN) through treatment with metal‐phenolic coordination complexes results in the formation of a stable hybrid structure. This reconstructed structure enhances electron transfer efficiency, leading to improved photocatalytic performance. Due to the photoluminescence quenching property of RN and its electronic synergy with tannic acid (T) and zirconium (Z), the supramolecular complexes of hybrid nanospheres (RNTxZy) with Pt nanoparticles or a biological workhorse, Shewanella oneidensis MR‐1, showed marked improvement in photocatalytic hydrogen production. The supramolecular hybrid particles with a metal‐phenolic coordination layer showed 5.6‐ and 4.0‐fold increases, respectively, in the productivities of hydrogen evolution catalyzed by Pt (Pt/RNTxZy) and MR‐1 (M/RNTxZy), respectively. These results highlight the potential for further advancements in the structural and photochemical control of supramolecular nanomaterials for energy harvesting and bio‐hybrid systems.

Organic probes for three‐photon fluorescence imaging in NIR‐II window: Design, applications, and perspectives

AbstractThree‐photon fluorescence (3PF) imaging is an emerging technology for imaging deep‐tissue submicroscopic structures by nonlinearly redshifting the excitation wavelength to the second near‐infrared (NIR‐II) window; thus, this approach has great advantages, including deep penetration depth, good spatial resolution, low background, and a high signal‐to‐noise ratio. 3PF imaging has been demonstrated to be a powerful tool for noninvasively visualizing all kinds of deep tissues in recent years. Benefiting from excellent biosecurity and structural controllability, the development of organic 3PF probes is highly important for advancing 3PF imaging in vivo. However, there is no summary of the generalizability of the design and recent progress in organic 3PF probes. Herein, this review introduces the fundamental principle of 3PF imaging and highlights the advantages of 3PF bioimaging. The molecular design of these organic 3PF probes is also summarized based on relative optical indices. Furthermore, different 3PF imaging application scenarios are listed in detail. In the end, the main challenges, significance of probe exploitation, and prospective orientation of organic probes for precise 3PF imaging are proposed and discussed for promoting future applications and clinical translation.

Planar Chiral Charge‐Transfer Cyclophanes: Convenient Synthesis, Circularly Polarized Light‐Responsive Photothermal Conversion and Supramolecular Chiral Assembly

We report herein a series of macrocycles in which the densely π‐stacked charge‐transfer (CT) donor/acceptor with naphthalenediimides (NDIs) or perylene diimide (PDI) as acceptor moiety pairing various donor moieties are locked by covalent bond. The X‐ray crystallography of C8BDT‐NDI reveals a short intramolecular π‐stacking distance around 3.4 Å and the existence of intermolecular donor/acceptor π‐stacking (3.7 Å). The intramolecular CT is highly dependent on the electron‐donating ability of donor moiety and replacing carbazole (C8KZ) with benzo[1,2‐b:4,5‐b']dithiophene (C8BDT) or dihydroindolo[3,2‐b]indole (C8DN) redshift CT absorption into NIR region. Notably, both C8BDT‐NDI and C8DN‐NDI demonstrate excellent photothermal performance, which is a result of the active non‐radiative pathways. Interestingly, the different molecular symmetry between donor and acceptor moiety endows C8BDT‐NDI and C8DN‐NDI with intrinsic planar chirality. The enantiomeric C8BDT‐NDI shows chiral selectivity for incident light, i.e., when irradiated by left‐circularly polarized light, (R)‐C8BDT‐NDI is more sensitive and a higher maximum stable temperature is achieved. While, enantiomeric C8DN‐NDI pack with different orientations forming M‐ and P‐handedness helix, respectively, demonstrating molecular planar chirality being transferred and amplified through molecular assembly. These results provide insight into the intramolecular charge transfer in enforced D/A π‐stacks in which CT interactions and planar chirality would be engineered through structural control.

Main cable structure analysis and construction control of short span suspension bridge within three-tower

The Feng Chu suspension bridge in Xiangyang holds the distinction of having one of the shortest span lengths among global suspension bridges, measuring less than half the length of conventional designs. This paper focuses on the engineering background of the bridge and delves into the analysis of the main cable structure and construction control methods for short-span suspension bridges with three towers. The study examines the impact of elastic modulus deviation in the main cable and the dead-load error of the stiffening beam on key parameters such as the unstressed length of the main cable, pre-deflection of the cable saddle, and mid-span elevation of the empty cable. Additionally, the effects of temperature, span, and cable length on the sag of the empty cable during the erection process are analyzed. Findings reveal that the elastic modulus and dead-load error significantly influence the unstressed length of the main cable, pre-deflection of the saddle, and the shape of the empty cable. This study establishes a relationship between changes in cable length and mid-span sag, providing valuable theoretical guidance for aligning and adjusting the main cable strands. Furthermore, synchronized alignment adjustments for the two mid-span sections are proposed to prevent main cable strand sliding, which may occur due to significant differences in sag between the sections.

Design of Self–Checking Digital Devices with Boolean Signals Correction Using Weight-Based Bose–Lin Codes

This paper proposes a method for designing self-checking digital devices with Boolean signals correction and weight-based Bose–Lin codes. Unlike previous studies, the method involves Boolean signals correction (BSC) in the concurrent error-detection (CED) circuit for those functions describing the outputs of source devices that participate in the formation of data symbols of weight-based Bose–Lin codes. In such codes, as in the absolute majority of uniform separable codes, several data vectors correspond to the same check vector; therefore, it is possible to choose a method for determining BSC functions. We describe an algorithm for determining their values for each input combination, considering the testability of the checker and transformation elements in the CED circuit. The method involves the so-called “base” structure for monitoring multi-output devices by output groups. With this method, the designer of a self-checking device has high variability in choosing the design method and can regulate important indicators (structure redundancy, controllability, energy consumption, and others). Experiments with combinational benchmarks from MCNC Benchmarks were carried out. According to the experimental data, the method has high efficiency in terms of structure redundancy compared to the duplication method widespread in practice. The method can be effective when designing real devices with fault detection used in all areas of technology, including critical application systems in industry and transport.

A study on active structural acoustic control using force radiation modes

Active Structural Acoustic Control (ASAC) is an effective method for sound radiation control. To solve the coupling effect or inconvenience problems existed in the application of conventional methods, by utilizing the characteristic of intuitive representation of radiated sound power through force radiation modes, the control forces are designed to make the total excitation force vector orthogonal to each dominant force radiation mode. Therefore, an ASAC method by utilizing force radiation modes is proposed, and detailed theoretical research and numerical calculation analysis are carried out. The research results indicate that the control force requirement can be intuitively obtained through the force radiation modes, and decoupled control of radiated sound power corresponding to each force radiation mode is achieved by the proposed method. Thus, the control strategy and system construction can be greatly simplified, and structural acoustic radiation can be effectively controlled.

Optimizing acoustic black hole structures for vibration control in beams: a comprehensive analysis

Acoustic black holes (ABH) have caught the attention of researchers because of their potential to absorb sound and control vibrations. This study presents an analytical framework that determines reflection coefficients in ABH structures. It focuses on implementing an acoustic black hole with a power-law tapered profile on beams. Moreover, this research investigates how various geometric shapes affect Damping Loss Factor (DLF) coefficients. This helps identify optimal approaches to optimize ABH structures based on specific requirements. The finite element method and a topology optimization solver were used to optimize various parameters systematically. The aim is to reduce weight and response, thereby improving the efficiency of ABH designs, especially in low-frequency insulation applications. The results demonstrate that ABH exhibits excellent performance in suppressing vibrations.