Metal Ring Research Articles

Anterior Matrix Systems for Composite Restorations: A Review.

In the field of restorative dentistry, composite resins have emerged as the most utilized materials. They revolutionized the cosmetic approach to anterior tooth treatment since their introduction to dental practice. In cases where one or more of the tooth's walls are absent, matrices are employed to assist in the creation of the proper anatomic contour and proximal contacts without the occurrence of gingival overhangs. Matrices come in a variety of designs suitable for various therapeutic conditions. Depending on the level of tooth destruction, they might range from a simple metal or plastic strip to a circumferential ring of metal surrounding the entire crown. Although the handling characteristics of modern composites have significantly improved, dentists still encounter challenges with the development of good interproximal contact and proper anatomical contour. The utilization of an anterior matrix system can be paramount in achieving these objectives.

The Modeling Design and Analysis of Spherical-Cymbal Piezoelectric Transducer

The paper proposes a model and analysis of spherical-cymbal piezoelectric transducer. First, we select materials for force-sensitive element, the metal end cap and ring and epoxy resin. The load transfer law of the spherical-cymbal piezoelectric transducer is analyzed. Then, resonant frequency test, axial vibration displacement test and ultimate static pressure test are implemented in experiment. The experimental results show that the spherical-cymbal piezoelectric transducer outperforms the traditional cymbal piezoelectric transducer. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P _max</i> value can increase up to 10% under different geometric parameters. This paper is conducted to provide new insight into the design of cymbal piezoelectric transducer.

V02-08 CREATION AND VALIDATION OF A SIMPLE TRAINING MODEL FOR PERCUTANEOUS RENAL ACCESS

You have accessJournal of UrologyCME1 Apr 2023V02-08 CREATION AND VALIDATION OF A SIMPLE TRAINING MODEL FOR PERCUTANEOUS RENAL ACCESS Ala'a Farkouh, Tyler Humphries, Matthew Buell, Akin S. Amasyali, Alphie Rotinsulu, Rose Leu, Kanha Shete, and D. Duane Baldwin Ala'a FarkouhAla'a Farkouh More articles by this author , Tyler HumphriesTyler Humphries More articles by this author , Matthew BuellMatthew Buell More articles by this author , Akin S. AmasyaliAkin S. Amasyali More articles by this author , Alphie RotinsuluAlphie Rotinsulu More articles by this author , Rose LeuRose Leu More articles by this author , Kanha SheteKanha Shete More articles by this author , and D. Duane BaldwinD. Duane Baldwin More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003232.08AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Establishing renal access remains the most challenging aspect during percutaneous nephrolithotomy. Adequate training of urology residents is essential, as improper access can lead to increased morbidity and potential mortality. The purpose of this video was to demonstrate the design, creation, and validation of a simple training model for renal access. METHODS: Using commercially available software, a mold of the renal parenchyma and collecting system was created from a patient’s CT Urogram and then 3D-printed. A silicone kidney model was created from this mold, giving a coronally bisected right kidney with a calyceal system. This model was embedded in ballistic gelatin, which simulated the surrounding muscles and subcutaneous tissue. The final position of the kidney and surrounding gelatin simulated prone PCNL of the right kidney. A small metal ring was used as the target for renal access and was placed in the upper calyx upon a grid to allow measurement of distance from target. A piece of calcium carbonate was embedded into the gelatin over the upper pole of the kidney and simulated a palpable 12th rib. The entire model was covered with an opaque sheet to simulate skin and fluoroscopy was used to guide renal access. Five urologists and 15 novices took part in establishing renal access following training. The primary endpoint was validation of this training model. Construct validity was evaluated by comparing the distance from the target between urologists and novices using the Mann–Whitney U test. Participants were then asked to fill out a survey about the training model to evaluate its face validity. RESULTS: All 5 urologists successfully entered the ring, corresponding to a 0 mm distance from the target. Of the novices, 67% missed the ring, with an average distance of 3.07 mm from the target (p=0.025). When asked if they felt the model is an accurate representation of the anatomy surrounding renal access, 90% answered yes and 10% were unsure. All felt that working on this model will increase their understanding of obtaining renal access. 75% were extremely likely to recommend it for training. CONCLUSIONS: This video demonstrates design, creation, and validation of a simple training model for renal access. Furthermore, it is simple, inexpensive, does not contaminate, and does not raise ethical concerns. Such models should be widely available for trainees to practice and comprehend the principle of obtaining renal access before their attempt in the operating room. Use of models like this could increase the skill of trainees and subsequently reduce patient morbidity. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e170 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Ala'a Farkouh More articles by this author Tyler Humphries More articles by this author Matthew Buell More articles by this author Akin S. Amasyali More articles by this author Alphie Rotinsulu More articles by this author Rose Leu More articles by this author Kanha Shete More articles by this author D. Duane Baldwin More articles by this author Expand All Advertisement PDF downloadLoading ...

Study of parameters of the avalanche diode generator

The article is devoted to the development and analysis of an avalanche diode generator. The equivalent circuit of the generator is considered and its simplified analysis is carried out. Using the elements of graphic analysis, the conditions of stability of generator oscillations were obtained. The original design of the avalanche diode generator is proposed and considered. A feature of the generator design is the use of a combined oscillating system, which is a three-dimensional resonator in the form of a metal ring made of aluminum alloy placed on a double-sided foil dielectric. Thanks to the top cover made of the same foil dielectric, the oscillating system has a closed nature. The electromagnetic energy supply and output system is made using printed technologies based on a double-sided foil dielectric. The avalanche diode is located in the center of this structure and has a thermal connection with the external radiator. On the one hand, such a decision allowed us to increase significantly the Q-factor of the oscillating system compared to the oscillating system made by the printed method and, at the same time, gave an opportunity to combine the developed auto-generator with other elements of the waveguide path made in the printed version. The developed generator has the possibility of both mechanical, by changing the volume of the resonator with the help of special backlash-free elements, and electronic adjustment, by changing the supply current. The article contains the results of experimental studies of the proposed design of the auto-generator, in particular the dependence of the output power on the frequency of oscillations and on the supply current, as well as the Q factor on the supply current. The research results indicate a fairly high Q-factor of such an oscillating system and, as a result, increased stability of oscillations. In addition, this design to a certain extent improves the overall manufacturability of the design and its material capacity in comparison with the waveguide version.

An Ultra‐Broadband Chirality Selective Metastructure Absorber using High Impedance Surface

AbstractIn this paper, an ultra‐wideband chirality selective metastructure absorber is proposed that enables differential absorption and reflection of circularly polarized waves in the terahertz (THz) range. The structure achieves circular dichroism (CD) by using asymmetrically split metal rings as fundamental meta‐atoms. Most critically, the high impedance surface and air‐resonant cavities are inserted separately in the meta‐atoms and dielectric substrate to enhance CD and broaden the bandwidth of absorption. The metastructure absorber can achieve more than 90% absorption of right circularly polarized waves at 0.675–1.244 THz, and it can maintain more than 90% reflection of left circularly polarized waves at 0.607–1.229 THz without changing the direction of rotation. Besides, its CD can reach more than 80% at 0.687–1.213 THz with a relative bandwidth of 55.3%. Spin‐selective absorption, which is closely related to breaking chiral symmetry, is investigated through power loss distribution, wide‐angle incidence, and scan parameter optimization. The proposed strategy is further validated in the THz band, and the polarization selection and manipulation techniques can be applied to chiral sensing/radio‐thermometry, circular polarization detectors/lasers, and molecular spectroscopy.

Experimental Research on Heating Transfer Improvement of Materials that Change Phase in Tunnels in Cold Regions

In tunnel heating systems, phase change materials may minimize the consumption of conventional electric energy, which is very considerate in the field of tunnel heating in cold regions. Because of the phase change material’s poor heat conductivity, its annual growth rate heat absorption and release is slower; thus, the majority of phase change heat storage systems must improve heat transmission. In this study, a spiral metal ring is implanted in the paraffin to improve heat transmission to achieve this objective using a concentric sleeve-type paraffin heat storage device as a medium. Experiments were performed out in order to determine the effects of heating rate, hot fluid flow rate, and the use of a spiral metal ring on the heat storage and release process of a thermal storage device. In comparison to the paraffin thermal storage device, the embedding of the spiral metal ring accelerates the internal thermal performance of the composite heat storage device, resulting in a more uniform temperature distribution. When the thermal radiation heating rate is 60°C, 65°C, or 70°C during the heat storage process, the heat storage time of the composite heating storage device is reduced by 59.2 percent, 44.4 percent, and 40.7 percent, respectively. When the ambient temperature is 26°C and the heat storage device’s starting temperature is 65°C, the exothermic time is reduced by 22.6 percent.

Designing an Innovative Electrospinning Strategy to Generate PHBV Nanofiber Scaffolds with a Radially Oriented Fibrous Pattern.

Electrospinning has contributed substantially to the construction of nanofibrous scaffolds for potential tissue engineering and regenerative medicine applications. However, conventional electrospinning only has the ability to generate and collect nanofiber scaffolds with a randomly oriented fibrous pattern, which lack the necessary cell alignment guidance function. In this study, a novel electrospinning fiber-collecting device was designed and developed by setting a series of small pin-ring-structured collectors on a large plain plate. Specifically, we demonstrated that the pin-ring-structured collectors, which were constructed by inserting a metal pin into the center of a metal ring, could collect the as-electrospun nanofibers with radially oriented structures in an innovative manner. We first investigated the suitable polymeric concentration for electrospinning poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and the optimum electrospinning concentration of PHBV was found to be 12% (w/v) PHBV dissolved in hexafluoroisopropyl alcohol (HFIP). Then, 12% (w/v) PHBV solution was electrospun into radially oriented nanofiber scaffolds using our novel electrospinning strategy, and their various performances were further compared with conventionally randomly oriented nanofiber scaffolds that were also produced from 12% (w/v) PHBV solution. The results showed that the radially oriented PHBV nanofiber scaffolds exhibited obviously enhanced mechanical properties and decreased hydrophobicity compared with the randomly oriented PHBV nanofiber scaffold controls. Importantly, the biological properties of radially oriented PHBV nanofiber scaffolds were also demonstrated to be enhanced, compared with randomly oriented PHBV nanofiber scaffolds, by effectively inducing cell alignment and significantly promoting cell proliferation. In sum, the present study indicates that our as-prepared nanofiber scaffolds with a radially oriented pattern are of great interest for advanced applications, such as wound dressings and tissue-engineered scaffolds.

Double-layer broadband transmission metasurface and its application in low sidelobe antenna

This study proposes a double-layer metasurface which is capable of conducting independent amplitude and phase modulation for transmitting x-polarized waves under y-polarized incidence. The phase modulation is controlled by regulating the opening angle of the middle metal ring. Meanwhile, amplitude modulation is achieved by adjusting the rotation angle of the opening ring structure. The cross-polarized transmission response achieves complete phase and amplitude coverage and exhibits wideband characteristic with which a 3 dB gain bandwidth of 54.6% (5.4–9.5 GHz). The polarization isolation level is lower than −20 dB. In the wideband frequency range, the average sidelobe level of phase-only modulated metalens antenna is less than −20 dB with the lowest value of −22.5 dB, and the intermediate sidelobe level of amplitude-phase independent modulated metalens antenna is less than −25 dB with the lowest value of −27.4 dB. Both numerical simulated and experimental results verify that the proposed metalens antenna realizes a 4.8 dB averages of the sidelobe level suppression compared with the phase-only modulation metalens antenna. Holding strong anti-interference performance due to its superiority in polarization isolation level and side lobe level, the proposed antenna embraces broad application prospects in point-to-point communication systems in jamming environments.

The effect of initial texture on multiple necking formation in polycrystalline thin rings subjected to dynamic expansion

In this paper, we have investigated, using finite element calculations, the effect of initial texture on the formation of multiple necking patterns in ductile metallic rings subjected to rapid radial expansion. The mechanical behavior of the material has been modeled with the elasto-viscoplastic single crystal constitutive model developed by Marin (2006). The polycrystalline microstructure of the ring has been generated using random Voronoi seeds. Both 5000 grain and 15000 grain aggregates have been investigated, and for each polycrystalline aggregate three different spatial distributions of grains have been considered. The calculations have been performed within a wide range of strain rates varying from 1.66⋅104s−1 to 3.33⋅105s−1, and the rings have been modeled with four different initial textures: isotropic texture, 001∥Θ Goss texture, 001∥ R Goss texture and 111∥ Z fiber texture. The finite element results show that: (i) the spatial distribution of grains affects the location of the necks, (ii) the decrease of the grain size delays the formation of the necking pattern and increases the number of necks, (iii) the initial texture affects the number of necks, the location of the necks, and the necking time, (iv) the development of the necks is accompanied by a local increase of the slip activity. This work provides new insights into the effect of crystallographic microstructure on dynamic plastic localization and guidelines to tailor the initial texture in order to delay dynamic necking formation and, thus, to improve the energy absorption capacity of ductile metallic materials at high strain rates.

High-efficiency continuous-flow microwave heating system based on metal-ring resonant structure

Continuous-flow microwave heating has been widely applied in liquid food processing, and the heating efficiency relies heavily on the dielectric property of loads with fixed dimensions in a certain cavity. Specifically, rectangular waveguides are widely applied, and straight pipes are usually inserted through the center of rectangular waveguides. However, maintaining high efficiency is always challenging since the dielectric property will vary with temperature. Therefore, a simple and cheap resonant structure is proposed in this paper to maintain high heating efficiency for loads with a large range of relative permittivity in both modeling and experiment. First, the straight pipe surrounded by metal rings in a rectangular waveguide with a short circuit terminal was introduced to concentrate the electric field in the pipe. Then, a multiphysics model was established to calculate the energy efficiency of various load permittivity. The position of the short circuit terminal and the dimensions of the metal ring were further optimized. Finally, energy efficiency experiments of different aqueous ethanol solutions and liquid foods and point temperature rise experiments of continuous-flow water were carried out, and the results showed that the proposed structure can be used to maintain high energy efficiency over large dielectric dynamic ranges compared with the conventional microwave heating system based on rectangular waveguides. Moreover, the effect of different parameters, the pipe permittivity, the pipe wall thickness and the metal ring gap, on the heating efficiency was discussed to show the robustness of the proposed structure.

Penile strangulation by a metal ring

Penile strangulation due to the metallic ring is an uncommon clinical entity that requires urgent attention to prevent irreversible nerve damage, and if neglected gangrene of the penis. Various methods have been described in the literature for removing constricting foreign bodies, but there is no consensus regarding an acceptable technique. We report the case of a 51-year-old man with a history of a metal ring used for sexual pleasure lodged over the shaft of his penis with an inability to remove the same.

A Compact and Low-Loss Tunable Bandpass Filter Using YIG/GGG Film Structures

A compact and low-loss magnetically tunable bandpass filter (BPF) is presented in this letter. The yttrium iron garnet/gadolinium gallium garnet (YIG/GGG) film structure is regarded as a resonator excited by a stepped terminal short-circuited stripline, and additional metal rings are plated on the other side of the RO4350 substrate. Two YIG/GGG film structures placed in parallel are directly coupled. This structure enhances the RF magnetic field, reduces filter loss, and suppresses parasitic response. The filter design and geometrical parameter optimization are first carried out using CST Studio Suite. When the magnetic field changes from 1820 to 7420 Oe, the filter is tuned from 5 to 19 GHz, with a 3-dB bandwidth (BW) of 62–107 MHz, insertion loss (IL) of less than 2 dB, and parasitic response suppression of about 20 dB over the entire tuning range (TR).

Metasurfaces of capacitively loaded metallic rings for magnetic resonance imaging surface coils

This work investigates the use of a metasurface made up of a two-dimensional array of capacitively loaded metallic rings to enhance the signal-to-noise ratio of magnetic resonance imaging surface coils and to tailor the magnetic near-field radio frequency pattern of the coils. It is found that the signal-to-noise ratio is increased if the coupling between the capacitively loaded metallic rings in the array is increased. The input resistance and the radiofrequency magnetic field of the metasurface loaded coil are numerically analyzed by means of an efficient algorithm termed the discrete model to determine the signal-to-noise ratio. Standing surface waves or magnetoinductive waves supported by the metasurface introduce resonances in the frequency dependence of the input resistance. The signal-to-noise ratio is found to be optimal at the frequency corresponding to a local minimum existing between these resonances.The discrete model is used in an optimization procedure to fit the structural parameters of a metasurface to enhance the signal-to-noise ratio at the frequency corresponding to this local minimum in the input resistance. It is found that the signal-to-noise ratio can be greatly improved if the mutual coupling between the capacitively loaded metallic rings of the array is made stronger by bringing them closer or by using rings of squared shape instead of circular. These conclusions derived from the numerical results provided by the discrete model are double-checked by means of numerical simulations provided by the commercial electromagnetic solver Simulia CST and by experimental results. Numerical results provided by CST are also shown to demonstrate that the surface impedance of the array of elements can be adjusted to provide a more homogeneous magnetic near-field radio frequency pattern that ultimately leads to a more uniform magnetic resonance image at a desired slice. This is achieved by preventing the reflection of propagating magnetoinductive waves at the edges of the array by matching the elements arranged at the edges of the array with capacitors of suitable value.

Study on vanadium dioxide based terahertz metamaterials with switchable functions from five-band absorption to triple-band plasmon-induced transparency

A bifunctional switchable terahertz metamaterial utilizing vanadium dioxide (VO2) able to dynamically convert from multiband absorption to multiband plasmon-induced transparency (PIT) is designed, which is consisted of four different-sized metallic split rings placed on a dielectric slab backed by a continuous VO2 film. Based on unique insulator-metal phase transition properties of VO2, the present functions of designed structural could be realized by changing the temperature of VO2. When the VO2 is in the conducting phase, it possesses five discrete absorption peaks with the frequencies of 1.30 THz, 1.48 Hz, 2.07 THz, 2.46 THz and 2.72 THz with average absorbance greater than 98.0%. When the VO2 is in the insulating phase, it exhibits three obvious PIT peaks, the transmittances of them are 79.5%, 95.3% and 99.7% at the frequencies of 1.57 THz, 1.75 THz and 2.09 THz, respectively. Effects of geometric parameters on absorption and transparency are investigated. Results revealed that the dimension changes of surface patterned arrays show an important role in controlling resonance responses of absorption and transparency behavior. The switchable VO2-based metamaterial could have great potential applications in the fields of smart absorption, terahertz optical switches, filters, and slow-light devices.

Dual-band terahertz absorber based on square ring metamaterial structure.

In this paper, a dual-band terahertz absorber based on metamaterial structure is designed, fabricated, and measured. The metal periodic array is located on the upper surface of a silicon wafer with a metal ground plane, while the metamaterial structure is created utilizing a square metal ring with four T-shaped metal strips loaded inside of the ring. Two absorption peaks are realized at 0.715 and 1.013 THz with high Q-factors of 152.1 and 98.3, respectively, under normal TE and TM polarized incidence. A prototype of the proposed metamaterial absorber is fabricated by electron beam lithography (EBL) and electron beam evaporation (EBE) technology. Furthermore, a terahertz time-domain spectroscopy (TDS) measurement system is employed to test the absorber sample, with good measurement results obtained. This work provides a new option for the design of multi-band terahertz metamaterial absorbers.

DUAL-MOBILITY CUPS CEMENTED INTO CAGE IN COMPLEX REVISION TOTAL HIP ARTHROPLASTY PROVIDE A LOW REVISION RATE AT MORE THAN TEN YEARS

Instability and aseptic loosening are the two main complications after revision total hip arthroplasty (rTHA). Dual-mobility (DM) cups were shown to counteract implant instability during rTHA. To our knowledge, no study evaluated the 10-year outcomes of rTHA using DM cups, cemented into a metal reinforcement ring, in cases of severe acetabular bone loss. We hypothesized that using a DM cup cemented into a metal ring is a reliable technique for rTHA at 10 years, with few revisions for acetabular loosening and/or instability.This is a retrospective study of 77 rTHA cases with severe acetabular bone loss (Paprosky ≥ 2C) treated exclusively with a DM cup (NOVAE STICK; SERF, DÉCINES-CHARPIEU, FRANCE) cemented into a cage (Kerboull cross, Burch-Schneider, or ARM rings). Clinical scores and radiological assessments were performed preoperatively and at the last follow-up. The main endpoints were revision surgery for aseptic loosening or recurring dislocation.With a mean follow-up of 10.7 years [2.1-16.2], 3 patients were reoperated because of aseptic acetabular loosening (3.9%) at 9.6 years [7–12]. Seven patients (9.45%) dislocated their hip implant, only 1 suffered from chronic instability (1.3%). Cup survivorship was 96.1% at 10 years. No sign of progressive radiolucent lines were found and bone graft integration was satisfactory for 91% of the patients.The use of a DM cup cemented into a metal ring during rTHA with complex acetabular bone loss was associated with low revision rates for either acetabular loosening or chronic instability at 10 years. That's why we also recommend DM cup for all high risk of dislocation situations.

Wireless Measurement of the Degradation Rates of Thin Film Bioresorbable Metals Using Reflected Impedance

A method using reflected impedance to determine the electrical degradation rates of bioresorbable metals for physically transient electronic devices is outlined. This approach uses known mutual inductor interactions with simple single turn disk coil geometries and a frequency measurement system to track the reduction of the mean thickness of a thin film metal ring as it degrades. Experiments using <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm {500~ \text {n} \text {m} }$ </tex-math></inline-formula> thick zinc rings, fabricated by photolithography, thermal evaporation and lift-off, found a mean degradation rate of 278 nm h−1 in 37 °C de-ionised water. Experiments in 37 °C 1 mM hydrochloric acid found two distinct periods of degradation and a total degradation rate of 632 nm h−1 that closely matched the degradation rate measured using profilometry of 608 nm h−1.

Analysis on electric impedance-controlled active ultrasonic horn in radial vibration

As a key component of high-powered ultrasonic vibration systems, ultrasonic horns play an important role in various practical application scenarios. Recent advances in longitudinal ultrasonic horns have enabled them to magnify the Langevin transducer's mechanical vibration and efficiently transmit the mechanical vibration to the mechanical load. However, limited research has been devoted to active radial ultrasonic horns in radial vibration. Here we propose an electric impedance-controlled active radial ultrasonic horn (ARUH) capable of tuning both resonance frequency and displacement magnification in radial vibration. The resulting device consists of a radially polarized piezoelectric ring connected with adjustable electric impedance and two metal rings with variable sections. The underlying mechanism is that the change of the converted mechanical impedance of the piezoelectric material by the external electric impedance connected to the piezoelectric material modulates the resonance frequency and displacement magnification of the ARUH. It can be found that the resonant frequency shifts to higher frequencies as the resistance increases and the resonant frequency shifts to lower frequencies as the inductance and capacitance increase, while the displacement magnification has the opposite trend to the resonance frequency. For example, the resonance frequency of the constant-section radial horn is 41130.2 Hz. When the inductance increases from −0.007 to 0.007H, the resonance frequency shifts from 41171.3 to 34606.2 Hz and the displacement magnification moves from 1.189 to 3.5. The experiments are conducted to verify the effectiveness of the resulting device, which is in good agreement with the simulated results and theoretical predictions. Our design with functionality and flexibility opens up possibilities for the design of ARUHs and may find important application prospects in diverse fields such as cold-drawn steel tubes and ultrasonic plastic welding.

Gradual Size Enlargement of Aluminum-Oxo Clusters and the Photochromic Properties.

Metallic clusters, assembled by functional motifs, possess the attribute of regulating the properties by changing inorganic and organic components. In this work, a series of aluminum-oxo clusters, [Al6O(dmp)4(Hdmp)2]·2iPrOH [Al6-1, H3dmp = 2,2-bis(hydroxymethyl)propionic acid], [Al6(H2thmmg)6]·2DMF·2H2O [Al6-2, H5thmmg = N-tris(hydroxymethyl)methylglycine], [Al8(OH)4(NAP-OH)12(MeO)7(MeOH)]Cl·7MeCN·3MeOH (Al8, HNAP-OH = 3-hydroxy-2-naphthoic acid), and [Al10(NA)10(MeO)20] (Al10, HNA = nicotinic acid), were obtained based on different carboxylic acids, realizing metallic ring size enlargement from 5.91 to 9.32 Å. They all exhibit good chemical stability. Importantly, the Al8 cluster displays obvious photochromic behavior from pale yellow to orange yellow, originating from the generation of photoinduced radicals in the metal-assisted ligand-ligand electron transfer process of 3-hydroxy-2-naphthoic acid (HNAP-OH). This work enriches the metal ring cluster chemistry and reports the example of the aluminum-oxo cluster-based photochromic material, developing a novel system of photochromic materials.

"Z"-Type Tilted Quasi-One-Dimensional Assembly of Actinide-Embedded Coinage Metal Near-Plane Superatoms and Their Optical Properties.

In this work, a novel discovery that the coinage-metal near-plane superatoms (CM-NPSs) formed by embedding actinide elements into the coinage metal rings can realize the "Z"-type tilted quasi-one-dimensional (1D) direct assembly is reported. This success can be attributed to the strong bonding between the overlapping parts of adjacent superatomic motifs. First-principles calculations reveal that the motifs maintain their geometric and electronic structures robustly during the assembly process. With the accumulation of motifs, the intensity of the absorption peak increases continuously in the ultraviolet-visible (UV-Vis) absorption spectra range of 300-450nm, resulting in the hyperchromic effect, which is closely related to the degree of the participation of Th atoms. Furthermore, the absorption spectra show a continuously tunable feature in the 450-900nm range, as the interlayer stacking pattern leads to a pronounced redshift. More importantly, the valence 5f-shells of Th atoms have an increased contribution to the final orbitals of electronic transition, which demonstrates the advantages of the active high angular momentum electrons of actinide elements in spectral properties. These findings provide a valuable reference for the direct artificial assembly of near-plane superatoms and optical properties of superatomic assemblies embedded with rare elements.