Hollow Shell Research Articles

Preparation and characterization of core-shell structured CaCO3-SiO2 and hollow silica nanoparticles and evaluation of their effects on cement mortar properties

CaCO3-SiO2 particles having a core-shell nanostructure were produced by a modified Stöber process using CTAB as a surfactant. Then, a porous structure composed of a silica shell was formed after the removal of the CaCO3 cores as templates from the nanocomposite. To evaluate phase constitutions and microstructures of prepared nanoparticles, XRD, TEM, and FESEM–EDX techniques were utilized. The main aim of this work was to examine the usability of prepared CaCO3-SiO2 and SiO2 hollow shell nanoparticles instead of OPC in structural applications. In this way, the mixtures of cement mortar were made by partial replacement of 1% of cement mass with prepared nanoparticles. The amounts of calcium hydroxide (CH), bound water, and calcium carbonate for the prepared mortars have been calculated after 7 and 28 days of hydration through thermal analysis of TG/DTG. The results indicated that the CH content decreased by adding prepared nanoparticles as a cement replacement. As CaCO3-SiO2 and hollow SiO2 nanoparticles were used, the compressive strengths of mortars were enhanced by 34 and 59%, respectively, after 28 days, which were higher than the increasing influences on flexural strengths (29 and 55%). The increasing intensity of the XRD peaks related to the C-S-H phases and the decline of the orientation index of CH in a mortar containing silica shell suggest that hydration was further completed, leading to a strength improvement. The SEM micrographs indicated that the addition of prepared nanostructures improved the interface properties inside mortar and caused the microstructure to be denser.

Regioselective encapsulation of Pd clusters in hollow polycrystalline shell

Zeolite catalysts have been widely applied in petroleum and chemical industries. Nano/hierarchical structure could improve the utilization efficiency of active sites, especially for metal species encapsulated in zeolites. However, the uniformity of zeolite surface and crystallinity would decrease, leading to low stabilization effect. Herein, we developed a seed-directed method to prepare Pd clusters (∼1.3 nm) regioselectively encapsulated in hollow polycrystalline shell of Silicalite-1 zeolite. In nitrobenzene hydrogenation reaction, the optimized Pd@S-1-hp showed a high conversion of 92.2 % at 110 °C, which is 40 % higher than that of Pd clusters in bulk zeolite. Sub-nano Pd species in polycrystalline shell could significantly shorten the diffusion length on the basis of strong microporous confinement effect. Catalytic hydrogenation activity remained stable after six cycles. This structure could be extended to heterogeneous reactions suffering from diffusion limitation.

Hollow Nanobox‐Shaped Cu2‐xS@ZnxCd1‐xS Heterojunction by Light Multireflection with Z‐Scheme Mechanism for Enhanced Photocatalytic Hydrogen Production

AbstractAchieving efficient spatial photoinduced charge separation and light utilization for improving the high photocatalytic activity is still a major obstacle. Here, a Cu2‐xS@ZnxCd1‐xS (Cu2‐xS@ZnCdS) heterojunction is reported featuring a distinctive core–shell hollow nanobox structure. The Cu2‐xS@ZnxCd1‐xS exhibits high photocatalytic activity in hydrogen evolution reaction (HER) at the rate of 8175 µmol∙g−1∙h−1 under visible light irradiation, outperforming pristine ZnCdS nanoparticles and Cu2‐xS hollow nanoboxes. The remarkable activity and outstanding stability of Cu2‐x@ZnCdS are attributed to the development of robust interfacial electric fields, and improved light multireflection absorption efficiency as well as the Z‐scheme mechanism. The electron paramagnetic resonance (EPR) and in situ X‐ray photoelectron spectroscopy (XPS) measurements gave the direct evidence of the formation of the Z‐scheme, which maintained the high redox potentials of each ZnCdS and Cu2‐xS. This study gives the guideline for the design of heterojunction with the Z‐scheme mechanism, leading to the high photocatalytic performance and remarkable stability.

Epitaxial Growth of a Three-Dimensional Hollow and Chestnut Shell Photothermal p-n Junction Photoanode.

The p-n junction, a widely studied semiconductor material structure, offers only limited improvements in photoelectrochemical (PEC) efficiency. Herein, a three-dimensional (3D) p-n junction h-Ta3N5@CoN featuring a stable chestnut shell hollow sphere structure and photothermal effect was synthesized by using an epitaxial growth strategy. The fine fibers within the sphere induce Rayleigh scattering, which scatters unabsorbed light, thereby enabling secondary absorption and enhancing light utilization. The quantum confinement effects generated by CoN fine fibers, which are sized in a few nanometers, inhibit the recombination of electron-hole pairs. Moreover, the lattice matching between Ta3N5 and CoN allows for smoother movement of carriers and nonradiative relaxation phonons along the lattice, thereby enhancing the transport of both carriers and heat. The obtained h-Ta3N5@CoN/FTO p-n junction photoanode, under near-infrared (NIR) auxiliary irradiation, demonstrates a photocurrent of 8.71 mA cm-2 at 1.23 VRHE. Moreover, the h-Ta3N5@CoN+NIR/FTO photoanode can sustain operation for 168 h, which, to my knowledge, surpasses the operational durations of all other Ta3N5-based photoanodes. This study synthesizes three-dimensional hollow chestnut shell photothermal p-n heterojunctions through an epitaxial growth strategy, endowing the material with a more efficient carrier separation and photothermal transfer efficiency.

Enhanced Ferroelectric Polarization in Au@BaTiO3 Yolk-in-Shell Nanostructure for Synergistic Boosting Visible-Light- Piezocatalytic CO2 Reduction.

Developing efficient photo-piezocatalytic systems to achieve the conversion of renewable energy to chemical energy emerges enormous potential. However, poor catalytic efficiency remains a significant obstacle to future practical applications. Herein, a series of unique Au@BaTiO3 (Au@BT) yolk-shell nanostructure photo-piezocatalyst is constructed with single Au nanoparticle (Au NP) embedded in different positions within ferroelectric BaTiO3 hollow nanosphere (BT-HNS). This special structure showcases excellent mechanical force sensitivity and provides ample plasmon-induced interfacial charge-transfer pathways. In addition, the powerful piezoelectric polarization electric field induced by the enhanced ferroelectric polarization electric field via corona poling treatment in BT-HNS further promotes charge separation, CO2 adsorption and key intermediate conversion. Notably, BT with single Au NP encapsulated into hollow nanosphere shell with reinforced polarization (Au@BT-1-P) shows synergistically improved photo-piezocatalytic CO2 reduction activity for producing CO with a high production rate of 31.29 µmol g-1 h-1 under visible light irradiation and ultrasonic vibration. This work highlights a generic tactic for optimized design of high-performance and multifunctional nanostructured photo-piezocatalyst. Meanwhile, these yolk-in-shell nanostructures with single Au nanoparticle as an ideal model may hold great promise to inspire in-depth exploration of carrier dynamics and mechanistic understanding of the catalytic reaction.

Self-assembly core–shell hollow fly ash sphere-bridged Ti3C2Tx MXene 3D spherical/ lamellar composites with specific electromagnetic wave absorption performance

A new A/B spherical/lamellar electromagnetic wave absorption (EWA) model was established, in which A phase was a spherical material with low dielectric constant and B phase was a lamellar 2D material with high dielectric constant. Insulative fly ash cenospheres (FA) and conductive Ti3C2Tx flakes were selected as the A phase and the B phase which acted as the framework (as well as core) and the interface builder (as well as shell) respectively to construct the novel 3D connected structure system via simple self-assembly. FA, a cheap power plants solid waste, was used as an insulating bridge for Ti3C2Tx to help to adjust the conductivity, the electromagnetic parameters and the impedance matching. The synergistic effect of the special heterogeneous structures and the moderate composition of FA and Ti3C2Tx endowed the composites with controllable complex permittivity and excellent EWA performances. FA@T0.35 exhibited a RLmin of − 50.94 dB at 3.5 mm and its widest EAB was 4.25 GHz at 2.0 mm. FA@T0.40 reached a RLmin of − 45.13 dB with an EAB of 4.03 GHz at 2.0 mm. The widest EAB was 4.19 GHz at only 1.5 mm. The work offers a new guideline for designing a high-performance EWA material by using waste materials.

Controllable Synthesis of Hollow Dodecahedral Si@C Core-Shell Structures for Ultrastable Lithium-Ion Batteries.

Silicon (Si) has attracted considerable attention as a promising alternative to graphite in lithium-ion batteries (LIBs) because of its high theoretical capacity and voltage. However, the durability and cycling stability of Si-based composites have emerged as major obstacles to their widespread adoption as LIBs anode materials. To tackle these challenges, a hollow core-shell dodecahedra structure of a Si-based composite (HD-Si@C) is developed through a novel double-layer in situ growth approach. This innovative design ensures that the nano-sized Si particles are evenly distributed within a hollow carbon shell, effectively addressing issues like Si fragmentation, volume expansion, and detachment from the carbon layer during cycles. The HD-Si@C composite demonstrates remarkable structural integrity as a LIBs anode, resulting in exceptional electrochemical performance and promising practical applications, as evidenced by tests in pouch-type full cells. Notably, the composite shows outstanding cycling stability, retaining 85% of its initial capacity (713 mAh g-1) even after 3000 cycles at a high current rate of 5000mA g-1. Additionally, the material achieves a gravimetric energy density of 369Wh kg-1, showcasing its potential for efficient energy storage solutions. This research signifies a significant step toward realizing the practical utilization of Si-based materials in the next generation of LIBs.

A Closed-Loop Nanosystem Based on Piezoelectric Sensor and Pd-Nanoshell Photothermal Ablation for Renal Denervation to Treat Hypertension.

Renal sympathetic nerves play a crucial role in the pathogenesis of hypertension, and renal denervation (RDN) is a new solution for patients with refractory hypertension. However, current RDN techniques show inconsistent results in clinical application probably owing to incomplete endovascular ablation of the sympathetic nerves and a lack of measures to localize and assess efficacy. In this study, a closed-loop RDN system consisting of a sensing unit with a piezoelectric thin-film sensor (PTFS) and a treatment unit with a hollow Pd nanoparticle shell (PdNPS) with a diameter of 202.0nm for photothermal neural ablation is constructed. The PTFS can monitor and collect arterial pulsation and blood pressure (BP) and direct PdNPS to maximize RDN. PdNPS maintains a local temperature of 58-62°C under near-infrared-II irradiation (1,064nm) to achieve effective RDN within a range of 90-120s treatment window. Photothermal ablation significantly inhibits the activities of renal sympathetic nerves post-procedure and after one month and reduces the elevation of BP by > 50%. The novel closed-loop system enables safe and efficient targeting, dynamic monitoring, and ablation of the renal sympathetic nerves. This closed-loop system provides a new strategy for RDN technology and even for treating sympathetic nerve-related chronic diseases.

Trifunctional Graphene-Sandwiched Heterojunction-Embedded Layered Lattice Electrocatalyst for High Performance in Zn-Air Battery-Driven Water Splitting.

Zn-air battery (ZAB)-driven water splitting holds great promise as a next-generation energy conversion technology, but its large overpotential, low activity, and poor stability for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) remain obstacles. Here, a trifunctional graphene-sandwiched, heterojunction-embedded layered lattice (G-SHELL) electrocatalyst offering a solution to these challenges are reported. Its hollow core-layered shell morphology promotes ion transport to Co3S4 for OER and graphene-sandwiched MoS2 for ORR/HER, while its heterojunction-induced internal electric fields facilitate electron migration. The structural characteristics of G-SHELL are thoroughly investigated using X-ray absorption spectroscopy. Additionally, atomic-resolution transmission electron microscopy (TEM) images align well with the DFT-relaxed structures and simulated TEM images, further confirming its structure. It exhibits an approximately threefold smaller ORR charge transfer resistance than Pt/C, a lower OER overpotential and Tafel slope than RuO₂, and excellent HER overpotential and Tafel slope, while outlasting noble metals in terms of durability. Ex situ X-ray photoelectron spectroscopy analysis under varying potentials by examining the peak shifts and ratios (Co2+/Co3+ and Mo4+/Mo6+) elucidates electrocatalytic reaction mechanisms. Furthermore, the ZAB with G-SHELL outperforms Pt/C+RuO2 in terms of energy density (797Wh kg-1) and peak power density (275.8mW cm-2), realizing the ZAB-driven water splitting.

Sustained-release effect of eggshell powder microcapsules on lavender essential oil

Eggshells are rich in Ca2+ and organic compounds, which can be taken as coupling agents for sustained-release materials. Essential oils are widely applied due to their excellent volatility, but poor sustained-release stability has limited their development. The study aimed to develop a novel eggshell powder (EP) sustained-release microcapsule, providing a new approach to protect the active ingredients of Lavender essential oil (LEO), and investigated the reasons for EP to regulate protein-polysaccharide microcapsule structure. Experimental results showed when the addition ratio of EP and Whey protein (WPI) was 1: 3, the dosage of LEO was 25%, the microcapsule displayed smooth and porous spherical structure. XRD and FT-IR indicated that a dense and orderly network structure was formed via the cross-linking reaction between eggshell powder and wall materials, which induced protein and polysaccharide to form special spherical hollow sustained-release shell structure through the calcium bridge (-COO-Ca-COO-), then achieved the sustained-release effect on LEO.

Nanorod inside hollow-nanosphere structured magnetoelectric nanocatalyst for remotely controlled electrocatalysis assisted environmental remediation

We introduce a highly efficient method for the catalytic breakdown of organic compounds using nanorods embedded within hollow nanospheres structured magnetoelectric nanocatalyst (MENC). MENCs were fabricated through a single-step process utilizing the ultrasonic spray pyrolysis technique. The dynamic electric dipole generation capability due to synergistic interaction between nanorods at the core and the hollow nanosphere shell creates a nanoscale magnetoelectric device capable of electrocatalysis-assisted water purification through advanced oxidation processes under remotely applied magnetic field excitation. Our study examines the electrocatalytic degradation of organic pollutants by MENCs under magnetic field excitation, achieving an unprecedented 90% removal efficiency for synthetic dyes. This remarkable efficiency is a result of surface redox reactions facilitated by electron and hole transfer, resulting in the production of Reactive oxygen species (ROS) such as O2•− and •OH. Additionally, antioxidant experiments were performed to confirm the ROS generation capability of MENCs under magnetic field excitation. Furthermore, trapping experiments performed employing specific scavengers for individual reactive species reveal the mechanism responsible for the magnetic field-driven catalytic breakdown of organic contaminants by MENCs. Interestingly, the MENCs exhibit >95% reduction in Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria, respectively, within 90 min of exposure to a (20 mT& 1.9 kHz) AC magnetic field.

The characterisation of passivation and colouring of Zn-Ni electroplated 2024 aluminium alloy in the presence of Cu+

ABSTRACT The objective of this study is to develop a black chromate conversion coating (CCC) that meets the rigorous corrosion resistance and conductivity requirements of aerospace electrical connectors. The Zn-Ni alloy was successfully electrodeposited on the surface of 2024 aluminium alloy, and a black conversion coating was achieved through Cu+-based colouring. The conversion solution consisted of 10–14 g L−1 CrO3, 5–10 g L−1 NaCl, 10–13 g L−1 CuCl, and 15–25 g L−1 65-68%HNO3. The performance of the CCC was comprehensively evaluated through various techniques, including macro-observation, SEM, EDS, EIS, polarisation curves, and conductivity testing. The experimental results demonstrated that the prepared CCC exhibited a uniform black gloss, and that the conversion coating layer was primarily composed of Zn, Ni, O, Cr, and other elements. This coating layer significantly improved the impedance of the Zn-Ni alloy, reducing the corrosion current density to 5.35 × 10−5A cm−2, thus greatly enhancing its corrosion resistance. Furthermore, the resistance of the prepared CCC on a nearly hollow cylindrical electrical connector shell specimen with a height of approximately 3 cm and an inner diameter of approximately 1.5 cm was only 1.7 mΩ, which demonstrates excellent conductivity.

2D kinetic-ion simulations of inverted corona fusion targets

Laser-driven “inverted corona” fusion targets have attracted interest as a low-convergence neutron source and platform for studying kinetic physics. The scheme consists of a hollow or gas-filled spherical shell made of deuterated plastic. The shell has one or more laser entrance holes (LEH), resembling a spherical hohlraum. The laser passes through the LEH’s and illuminates the interior surface of the shell, ablating a plasma that travels inward towards the target center. Long ion mean free paths in the converging plasma can lead to significant interpenetration, atomic mix, and other kinetic effects. In this work we report on numerical simulations of inverted corona targets using the kinetic-ion, fluid–electron hybrid particle-in-cell (PIC) approach in 2D RZ geometry. 2D simulations suggest that shape effects do not have a significant impact on plasma evolution and observed yield trends are primarily the result of 1D kinetic mix mechanisms. Simulations are also compared against available experimental data recorded at the OMEGA laser facility. In particular, synthetic x-ray emission images show good qualitative agreement with experimental results, albeit with an apparent timing discrepancy for the two-sided vacuum target. More generally, we demonstrate the potential of hybrid-PIC simulations for full-system modeling and experimental design, including collisional absorption of laser energy, plasma evolution, mix, and fusion burn.

Convenient immobilization of chiral imidazolidinone to hollow polystyrene nanospheres (HPNs) for efficient heterogeneous enantioselective Friedel-Crafts reaction

The current anchoring of chiral imidazolidinones to solid supports to achieve heterogeneous catalysis usually involves the 5–8 steps for the synthesis of ready-to-anchor precursors bearing anchoring points and following immobilization to solid supports, leading to a high-cost for large-scale application. In this study, the anchoring steps of ready-to-anchor chiral imidazolidinone, (2S,5S)-5-benzyl-2-(tert‑ butyl)-3-methylimidazolidin-4-one (MacM), is shortened, including the four-step synthesis of MacM bearing bromine anchoring point in 18.3 % overall yield using phenylalanine as a raw material and covalent immobilization to well-shaped hollow polystyrene nanospheres (HPNs) bearing –B(OH)2 groups via Suzuki coupling in 1.2 mmol g-1 loading of MacM with an utilization of 96 %. The as-fabricated HPNs-supported chiral imidazolidinone (MacM@HPNs) possesses the morphology of hollow interior, mesoporous shell and thin shell thickness, providing fast mass transfer for reactants to quickly access to the active sites of anchored MacM. In the heterogeneous Friedel-Crafts reaction of acroleins and N-methylindoles, MacM@HPNs shows the similar moderate to good yields (79–88 %) in good to excellent selectivities (83–97 % ee) as homogeneous MacM. Furthermore, the catalyst maintains its catalytic performances without a significant decline in yield and enantioselectivity during the reuses. Overall, this study presents a more economical strategy for anchoring chiral imidazolinones to well-shaped polystyrene with the architectural structures suitable for achieving fast mass transfer of reactants, offering a reference way to anchor other chiral imidazolidinones and achieve the efficient synthesis of optically active molecules.

Tuning the shell thickness of N-doped interconnected hollow carbon sphere for the electrochemical sensing of antibiotic drug chloramphenicol.

N-doped hollow carbon spheres (NHCSs) with different shell thicknesses are constructed using various amounts of SiO2 precursor. An interconnected framework with diminished wall thickness ensures an efficient and continuous electron transport which helps to enhance theperformance of NHCS. Improvement of the electrocatalytic performance was shown in the determination of antibiotic drug chloramphenicol (CAP) due to theunique hollow thin shell morphology, ample defect sites, accessible surface area, higher surface-to-volume ratio and ansynergistic effect. Boosted electrocatalytic activity of 1.5 N-doped HCS (1.5 NHCS) was applied to detect CAP with a linear range and detection limit of 1-1150µM and 0.098µM (n = 3), respectively, with superior storage stability and considerable sensitivity. These results suggest that the proposed work can besuccessfully applied to the determination of CAP in milk and water samples.

Charge Detection Mass Spectrometry Reveals Favored Structures in the Assembly of Virus-Like Particles: Polymorphism in Norovirus GI.1.

The main capsid protein (CP) of norovirus, the leading cause of gastroenteritis, is expected to self-assemble into virus-like particles with the same structure as the wild-type virus, a capsid with 180 CPs in a T = 3 icosahedron. Using charge detection mass spectrometry (CD-MS), we find that the norovirus GI.1 variant is structurally promiscuous, forming a wide variety of well-defined structures, some that are icosahedral capsids and others that are not. The structures that are present evolve with time and vary with solution conditions. The presence of icosahedral T = 3 and T = 4 capsids (240 CPs) under some conditions was confirmed by cryo-electron microscopy (cryo-EM). The cryo-EM studies also confirmed the presence of an unexpected prolate geometry based on an elongated T = 4 capsid with 300 CPs. In addition, CD-MS measurements indicate the presence of well-defined peaks with masses corresponding to 420, 480, 600, and 700 CPs. The peak corresponding to 420 CPs is probably due to an icosahedral T = 7 capsid, but this could not be confirmed by cryo-EM. It is possible that the T = 7 particles are too fragile to survive vitrification. There are no mass peaks associated with the T = 9 and T = 12 icosahedra with 540 and 720 CPs. The larger structures with 480, 600, and 700 CPs are not icosahedral; however, their measured charges suggest that they are hollow shells. The use of CD-MS to monitor virus-like particles assembly may have important applications in vaccine development and quality control.

Single atomic Fe-dispersed hollow carbon spheres coated with Co3O4 synergistically catalyze oxygen reduction and oxygen evolution reactions

It is highly expected to construct an efficient electrocatalyst having dual active sites that can simultaneously catalyze both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in Zn-air batteries (ZABs). In this study, a new core-shell nanostructure (Co3O4/Fe-N4/HCS) consisting of single atomic Fe (Fe-N4)-dispersed hollow carbon spheres (Fe-N4/HCS) coated with Co3O4 nanoparticles (NPs) were successfully synthesized with SiO2 templates by a coating-polymerization-etching preparation strategy. Benefit from a synergistic effect of Co3O4 and Fe-N4 dual active species with unique HCS structure, Co3O4/Fe-N4/HCS displayed outstanding activity in both ORR (half-wave potential = 0.88 V) and OER (overpotential at 10 mA cm−2 = 0.33 V), respectively. Meanwhile, compared to Co3O4/Fe-N4/C with Co3O4 NPs on Fe-N4/C, Co3O4/Fe-N4/HCS with Co3O4 NPs on Fe-N4/HCS exhibits a higher stability during electrochemical processes depending on the stronger interaction between the Co3O4 NPs and atomic dispersed Fe-N4 sites embedded in unique HCS structure. Particularly, the ZABs fabricated by Co3O4/Fe-N4/HCS demonstrates a higher specific capacity (688.7 mAh gZn−1) and superior cycling durability over 80 h. The presence of the electron transfer from Co3O4 to Fe-N4 in Co3O4/Fe-N4/HCS, enables Fe-N4 bonded carbon electron deficiency. This promotes the deposition of Co3O4 NPs and enhances metal-HCS support interactions, which combined with a protecting effect of hollow carbon spherical shell on Co3O4 NPs inside the shell, achieving excellent catalytic stability. This research introduces a novel approach to design dual active sites as high-performance bifunctional ORR/OER catalysts.

Multi-modal triggered-release sonodynamic/chemo/phototherapy synergistic nanocarriers for the treatment of colon cancer.

Most colon cancer patients are diagnosed at an advanced stage, with a grim prognosis. In clinical, various combination therapies have been employed to enhance the efficacy of colon cancer treatment. The essence of combined treatment is the judicious selection and combination of various treatment units. Phototherapy (PT), sonodynamic therapy (SDT), and chemotherapy are treatment modalities that rely on the active molecules to treat tumors, and have been demonstrated to synergistically enhance tumor treatment efficacy. However, the differences in the metabolism of active molecules and hypoxic microenvironment of tumors have limited the synergistic effects of the aforementioned methods. To address this significant issue, in this study, we utilized polydopamine (PDA) as the encapsulated material to form a rigid shell that contains the therapeutic molecules IR-780 and methotrexate (MTX) on the surface of perfluorohexane (PFH) microdroplets through self-assembling method to develop an SDT/chemotherapy/PT combined nanoparticles (SCP NPs). Transmission electron microscopy (TEM) revealed that the nanoparticles exhibited a hollow shell structure, with an average size of approximately 100nm. SCP NPs have excellent stability and biocompatibility in both in vitro and in vivo. The absorption and emission spectrum of the loaded IR-780 did not exhibit any significant shift, and the photothermal temperature rose to 92°C. Their ultrasonic cavitation effect was good and their cell inhibitory effect of MTX was maintained. SCP NPs can achieve multi-modal triggered release through ultrasound, laser irradiation, and pH, ensuring a simultaneous accumulation of therapeutic molecules in the tumor area and effectively alleviating tumor hypoxia. Additionally, both the near-infrared fluorescence (NIF) signal and the ultrasonic cavitation signal of the nanoparticles can be utilized for tracking and monitoring treatment efficacy. Most notably, SCP NPs exhibited outstanding synergistic treatment effects at low intervention levels, resulting in a 67% cure rate of tumors. These results provide an experimental basis for developing the new clinical treatments for colon cancer.

Dynamic Analysis of 2D FG Porous Thick Cylindrical Shells Under Thermal Shock

In this research, a thick hollow cylindrical shell made of bidirectional functionally graded open cell porous materials under internal thermal shock according to the classical theory of linear thermo-elasticity is examined for the first time. The cylinder is made of a porous cellular material and its porosity varies along both radial and axial directions continuously. The governing motion equations are obtained by using 2D-axisymmetric theory of linear thermo-elasticity rather than shell theories. This theory represents thickness stretching and gives more precise results. Graded finite element method is employed to model the problem. Applying this method rather than conventional FEM leads to more accurate results, especially for dynamic analyses. The cubic higher order element is used for dividing the solution domain. To obtain transient temperatures, Crank–Nicolson algorithm is used and then the Newmark procedure is used to derive time responses of displacement and stress components. The time history of displacements and stress components for different radial and axial power law exponents, porosity coefficient, boundary conditions, length-to-thickness ratio and two different porosity patterns are investigated in detail. The obtained results show that thermal-induced vibration is generally caused by hoop stress, and frequency and amplitude of vibrations and velocity of stress waves are considerably influenced by the porosity distribution, porosity coefficient and power law exponents in both directions.

Горячее деформирование корпусных заготовок в изотермических условиях

Core operations with hollow products, having a periodically changing internal profile, consists in the final machining of press forgings. However, at the same time, metal rejects are high, and despite the high quality of the products obtained, their mechanical characteristics do not always meet the requirements of functioning. For the equipment units, when subjected to heavy loads, the parts are usually made of high-strength materials. Due to the complexity of the work on a workpieces made of high-strength alloys, operations are carried out with heating of the deformed zone of the in-process part or with a total heating. The use of slow deformation in the hot state under certain speed conditions is promising. The process of the internal pattern formation for hollow shells made of titanium alloy VT6 is viewed. These products are mainly used as various airframes and are made using special methods of mechanical engineering. Due to the use of high-strength billet materials, there are difficulties with the mechanization of the production methods. The article evaluates force conditions for generation of geometry on the shells based on CAE modeling. The simulation was performed in the deform complex. The focus of the research was on the assessment of deformation forces and stress intensities. The influence of deformation ratio, strain rates, punch geometry on the strength of the process and stress intensity has been revealed. A regression equation to estimate the forces of the process is deduced. Recommendations on the design of fillets forming operations have been obtained. Deformation modes aimed at achieving rational power modes, respectively, loads on the tool, which indirectly affects its durability, as well as the stress condition in the product, have been found.