Planar Structure Research Articles

Computing four-point functions with integrability, bootstrap and parity symmetry

The combination of integrability and crossing symmetry has proven to give tight non-perturbative bounds on some planar structure constants in N=4 SYM, particularly in the setup of defect observables built on a Wilson-Maldacena line. Whereas the precision is good for the low lying states, higher in the spectrum it drops due to the degeneracies at weak coupling when considering a single correlator. As this could be a clear obstacle in restoring higher point functions, we studied the problem of bounding directly a 4-point function at generic cross ratio, showing how to adapt for this purpose the numerical bootstrap algorithms based on semidefinite programming. Another tool we are using to further narrow the bounds is a parity symmetry descending from the N=4 SYM theory, which allowed us to reduce the number of parameters. We also give an interpretation for the parity in terms of the Quantum Spectral Curve at weak coupling. Our numerical bounds give an accurate determination of the 4-point function for physical values of the cross ratio, with at worst 5-6 digits precision at weak coupling and reaching more than 11 digits for ’t Hooft coupling λ4π∼4.

High-Performance CsPbBr3 Quantum Dot/ZTO Heterojunction Phototransistor with Enhanced Stability and Responsivity.

Although all inorganic metal halide perovskite quantum dots (QDs) have shown great potential in photodetectors, many reported devices still suffer from low responsivity due to poor mobility and high defect densities. To overcome these challenges, heterojunction structures that separate electron and hole pathways have emerged as a promising approach to improve the responsivity by reducing radiative recombination. Two-dimensional materials such as graphene and MoS2 have been integrated with perovskites to enhance performance; however, these materials often lead to high dark-state currents, which hinder the on/off ratios in photodetectors. Hence, identifying alternative functional materials that can complement perovskite QDs while minimizing these drawbacks is critical. Amorphous metal oxide semiconductors, such as zinc tin oxide (ZTO), have attracted attention as high-performance channel materials in thin-film transistors (TFTs) due to their high field-effect mobility, thermal stability, and ability to be processed at low temperatures over large areas. However, ZTO suffers from persistent photoconductivity (PPC) caused by oxygen vacancies, which leads to slow response times and prolonged conductivity after light exposure, thereby limiting its effectiveness in optoelectronic devices. In this work, we demonstrate a high-performance phototransistor using a planar heterojunction structure composed of CsPbBr3 quantum dots and ZTO via a simple solution-processing method. This device exhibits a responsivity of over 103 A/W, a specific detectivity of 7.0 × 1014 Jones, and an on/off ratio of 5 × 104 under 390 nm light illumination with an intensity of 0.03 mW/cm2. The combination of ZTO and CsPbBr3 QDs offers significant improvements over devices that lack either layer, showcasing superior performance compared to that of most perovskite photodetectors.

Mechanism and Structural Defects of Zinc Film Deposited on a Copper Substrate: A Study via Molecular Dynamics Simulations

Epitaxial growth can be used to guide the controllable growth of one metal on the surface of another substrate by matching the interface lattice, thus improving the dendrite tendency of metal growth. The atomic arrangement of the Cu (111) crystal plane of the FCC structure is similar to that of the Zn (0002) crystal plane of the HCP structure, which is theoretically expected to promote the heterogeneous epitaxial nucleation growth of metal zinc under low strain. In this paper, the molecular dynamics method is used to simulate the atomic process of zinc film growth on the Cu (111) surface. It is found that the behavior of zinc-adsorbed atoms on the substrate surface conforms to the epitaxial growth mode. The close-packed structure grown along the (0002) direction of the layered clusters is tiled on the Cu (111) surface, forming a highly ordered low-lattice-mismatch interface. When a large area of layered zinc clusters cover the substrate, the growth mode will change from heteroepitaxial growth to homoepitaxial growth of Zn atoms on the zinc film, forming a lamellar distribution composed of FCC and HCP structure grains. Polycrystalline zinc film with a planar structure with a (0002) surface preferred a crystal plane. The increase in incident energy is helpful in improving the quality of zinc films, while the deposition rate, corresponding to the deposition temperature and electrolyte ion concentration, has no significant effect on the surface morphology and crystal structure of single metal films. In summary, the atomic arrangement of the Cu (111) surface has a strong guiding effect on the atomic ordered arrangement in the zinc film crystal, which is suitable for the epitaxial deposition of the substrate to induce the ordered growth of the Zn (0002) crystal plane.

Isolation and Bioassay of Linear Veraguamides from a Marine Cyanobacterium (Okeania sp.)

Marine cyanobacteria have gained momentum in recent years as a source of novel bioactive small molecules. This paper describes the structure elucidation and pharmacological evaluation of two new (veraguamide O (1) and veraguamide P (2)) and one known (veraguamide C (3)) analogs isolated from a cyanobacterial collection made in the Las Perlas Archipelago of Panama. We hypothesized that these compounds would be cytotoxic in cancer cell lines. The compounds were screened against HEK-293, estrogen receptor positive (MCF-7), and triple-negative breast cancer (MDA-MB-231) cells as well as against a broad panel of membrane-bound receptors. The planar structures were determined based on NMR and MS data along with a comparison to previously isolated veraguamide analogs. Phylogenetic analysis of the collection suggests it to be an Okeania sp., a similar species to the cyanobacterium reported to produce other veraguamides. Veraguamide O shows no cytotoxicity (greater than 100 μM) against ER-positive cells (MCF-7) with 13 μM IC50 against MDA-MB-231 TNBC cells. Interestingly, these compounds show affinity for the sigma2/TMEM-97 receptor, making them potential leads for the development of non-toxic sigma 2 targeting ligands.

Probing electronic and vibrational structures of TaCn-/0 (n = 2-4) using high-resolution photoelectron spectroscopy and theoretical calculations.

We report the high-resolution photoelectron spectroscopy of transition metal carbide cluster anions TaCn- (n = 2-4) using a cryogenic ion trap combined with the slow electron velocity imaging (cryo-SEVI) technique. From the vibrationally resolved photoelectron spectra and associated abinitio calculations, the electron affinities of TaCn (n = 2-4) were determined with high precision: 1.818(2), 2.202(5), and 2.431(2) eV, respectively. The electronic and vibrational structures observed in the photoelectron spectra were interpreted using density-functional theory and coupled-cluster singles and doubles with perturbative triples calculations. Both the neutral TaCn clusters and their anions exhibit planar C2v structures, where the Ta atom bridges each C atom. Furthermore, we observed the spin-orbit splitting in the ground state of TaC2 (X̃4B1), with a measured splitting of 256(25) cm-1. This splitting is well explained by the calculated E1/2(±3/2)-E1/2(±1/2) splitting of 216cm-1, obtained using the MRCI+SOC method.

Prediction of Shear Strength in Anisotropic Structural Planes Considering Size Effects

It is essential to elucidate the shear mechanical behavior of structural planes to assess the risk to rock masses and protect them from shear failure. Current research on shear mechanical behavior is focused on isotropic structural planes with the same lithology on both sides. However, anisotropic structural planes, commonly found in nature, may exhibit unique mechanical behavior that differs from isotropic structural planes. Therefore, it is necessary to study the factors affecting the shear strength of the anisotropic structural planes. In this paper, the direct shear numerical tests on anisotropic structural planes were carried out using the three-dimensional distinct element code (3DEC) based on the laboratory test. The numerical test results illustrate that the error between the peak shear strength of the numerical test and the laboratory test is basically within 10%. The shear stress-displacement curves of the numerical and laboratory tests are similar, which verifies the accuracy of the numerical test. According to the Barton standard sections, anisotropic structural plane models with different roughness and size were established, and the direct shear numerical tests with different normal stresses were carried out. To predict the peak shear strength of the anisotropic structural planes, one hundred and eighty-one sets of direct shear numerical test data were selected. Normal stress, roughness, compressive strength of soft and hard rock masses, basic friction angle of soft and hard rock masses, and structural plane size were used as input parameters to establish a back propagation (BP) neural network model. The research results show that, under identical conditions, the shear strength of the anisotropic structural planes decreases as the structural plane size increases. On the contrary, the shear strength increases with the increasing structural plane roughness and normal stress. For the BP neural network prediction model, the root mean square error (RMSE) and coefficient of determination (R2) of the training set are 0.441 and 0.957. For the test set, the RMSE is 0.489, and R2 is 0.947, which indicates that the predicted values are in good agreement with the actual values.

Electronic structures and spin frustration in Ln3O (Ln = Ce, Sm, Gd) neutrals and anions determined by anion photoelectron spectroscopy.

The results of a combined experimental and computational study on Ln3O (Ln = Ce, Sm, and Gd) anion and neutral clusters are presented and analyzed. These three Ln's were specifically targeted because they vary in their spin state and orbital angular momentum associated with the 4fN subshell occupancies. From the anion PE spectra of Ce3O-, Sm3O-, and Gd3O- measured with 2.330 and 3.495eV photon energies, we determine the adiabatic electron affinities of the corresponding neutrals to be 0.83 ± 0.03, 1.11 ± 0.05, and 1.17 ± 0.05eV, respectively. The lowest energy features in all three spectra can readily be reconciled with molecular structures in which the O-atom is central to all three Ln centers, with Ce3O-/Ce3O assuming pyramidal structures and Sm3O-/Sm3O and Gd3O-/Gd3O assuming planar structures. Computationally, the lowest-energy structure of neutral Ce3O is a kite-like structure, which is not consistent with the observed spectrum. The kite-like and pyramidal structures of Ce3O- are predicted to be nearly isoenergetic. Electronic states in which all three 4fN centers are ferromagnetically coupled are predicted to be energetically favored for all species, but spin-frustrated states in which one 4fN center is antiferromagnetically coupled to the remaining centers are computed to lie 0.05eV higher in energy than the FM-coupled states for Ce3O- and Sm3O-. The PE spectrum of Sm3O- exhibits striking anomalies in the photoelectron angular dependence. This effect is attributed to strong photoelectron-valence electron interactions that drive nominally forbidden changes in the Mf state of the remnant neutral.

Theoretical study on fused 1,2,3,4-tetrazine-1,3-dinitroxide derivatives under external electric field.

Considering the excellent properties of 1,2,3,4-tetrazine-1,3-dinitroxides, several types of energetic derivatives have been synthesized from them. Among them, [1,2,5] oxadiazolo [3,4-e] [1,2,3,4]-tetrazine-4,6-Di-N-dioxide (FTDO), 5,7-dinitrobenzo-1,2,3,4-tetrazine-1,3-nitrogen dioxide (DTND), and [1,2,3,4] tetrazino [5,6-e] [1,2,3,4] tetrazine-1,3,8-tetraoxide (TTTO) are considered excellent energetic materials. However, there is limited research on their behavior under electric fields. The effect of electric fields was studied using density functional theory to calculate trigger bond changes, strain energy, chemical reactivity, and surface electrostatic potential. The results indicate that the planar structure of FTDO is more unique than that of DTND and TTTO, and its trigger bond is located at special position. Increased electric field strength can lengthen the trigger bond, increase sensitivity, and reduce strain energy of FTDO. Under a positive electric field, DTND and TTTO have longer trigger bond lengths, increased sensitivity, and increased strain energy, while exhibiting the opposite behavior under a negative electric field. Electric fields can affect the chemical reactivity of the all three derivatives. FTDO is less active under positive electric fields, DTND is more active under both electric fields, and TTTO becomes more active under negative electric fields. Finally, the electric field can expand their absorption spectrum range, affecting electron transfer between fragments. All calculations in this article were completed on Gaussian 16 software. The calculation levels are B3LYP/6-311G**, B3LYP/Def2-TZVPP, and PBE1PBE/6-311G**. Multiwfn and VMD were used for wave function analysis. Electric fields have a strength range of - 0.02 to 0.02 a.u., with a growth gradient of 0.01 a.u.

Sr2Zn(C3N3O3)2: An Alkaline Earth and d10 Transition Metal Based Ultraviolet Cyanurate with Large Birefringence.

Birefringent properties of materials have garnered significant interest in both the military and civilian scientific domains. The rational combination of mixed alkaline earth and fully filled d10 transition metal cations in the cyanurates may achieve large birefringence and good transparency in the UV region by regulating planar π-conjugated (C3N3O3)3- anions. This work successfully synthesized a new metal cyanurate Sr2Zn(C3N3O3)2 (SZCY) by a solid-state cyclo-trimerization reaction featuring a planar π-conjugated laminar crystal structure. SZCY displays a wide bandgap (Eg ∼ 5.30 eV) and large birefringence (Δn = 0.31 at 1064 nm). The first-principles calculation revealed that the optical properties of SZCY are mainly due to the parallel arrangement of (C3N3O3)3- groups.

Discovery of Dual ROCK1/2 Inhibitors from Nocardiopsis sp. under Metal Stress.

Rho-associated protein kinase (ROCK) inhibitors are promising therapeutic agents for reducing elevated intraocular pressure in patients with glaucoma. We explored new ROCK inhibitors derived from bioactive metabolites produced by microbes, specifically cryptic metabolites from Nocardiopsis sp. MCY7, using a liquid chromatography-mass spectrometry-based chemical analysis approach integrated with metal stress-driven isolation. This strategy led to the identification of two previously undescribed linear peptides, nocarnickelamides A and B (1 and 2), and an unreported cittilin derivative, cittilin C (3). The planar structures of 1-3 were elucidated using UV spectroscopy, high-resolution mass spectrometry, and nuclear magnetic resonance. The absolute configurations of 1 and 2 were assigned using the advanced Marfey's method. Biological assays demonstrated that nocarnickelamides (1 and 2) exhibited dual inhibitory activity against ROCK1 (IC50 29.8 and 14.9 μM, respectively) and ROCK2 (IC50 27.0 and 21.9 μM, respectively), with molecular simulations suggesting binding to the ATP-binding site. In human trabecular meshwork cells, 2 significantly inhibited the activation of ROCK-regulated cytoskeletal contraction markers such as the myosin light chain. Nocarnickelamide B (2) is a novel dual ROCK1/2 inhibitor and a potential pharmacophore for designing new therapeutic agents to reduce intraocular pressure in glaucoma.

Synthesis of Alternating Copolymers with Substituents Containing Heteroatoms and the Regulation of Nontraditional Intrinsic Luminescence.

Compared with other sequence structure polymers, alternating polymers usually have several unique properties, but their properties are more sensitive to changes in structure. By investigating the relationship between the structure and properties of alternating polymer chains, polymers with desired properties can likely be synthesized. In this study, a series of alternating copolymers of 1,1-diphenylethylene (DPE) derivatives and styrene derivatives, which exhibit nontraditional intrinsic luminescence (NTIL), are synthesized using living anionic polymerization. By changing the bridge plane structure of the DPE derivatives and the substituent groups of the styrene derivatives, the rigid chain structure of the alternating copolymers containing styrene derivative with a large steric hindrance is altered, and this change is observed by the altered fluorescence properties. Based on the results from experimental tests and theoretical simulations, copolymers with bridge plane structures have higher fluorescence emission intensities; moreover, a balance is observed between the electronic and steric hindrance effects of substituents on the fluorescence intensities, and polymer chains that are too rigid cause a decrease in the fluorescence intensities. Thus, the influence of the chain structure on the fluorescence properties of NTIL polymers cannot be disregarded.

Automatic Identification of Rock Discontinuity Sets by a Fuzzy C-Means Clustering Method Based on Artificial Bee Colony Algorithm

The identification and classification of rock discontinuities are crucial for studying rock mechanical properties and rock engineering optimization design and safety assessment. An improved artificial bee colony (ABC) algorithm is proposed and combined with the fuzzy C-means (FCM) clustering method to develop an FCM clustering method for automatically identifying rock discontinuity sets based on the ABC algorithm (FCM-ABC method). All the equations of the method are fully developed, and the methodology is presented in its entirety. Moreover, the rock structural planes are investigated in a gold mine in China using a ShapeMetriX 3D system. Based on the measured structural plane data, the specific calculation process, selection of parameters, effectiveness of grouping, and the dominant orientation of the proposed method for structural plane occurrence classification are analyzed and discussed, and satisfactory clustering results are achieved. This validates the validity and reliability of the method. Furthermore, multiple aspects of the excellent performance of this method for the identification of structural plane sets compared to traditional clustering methods are demonstrated. In addition, the significance of structural plane identification in the prevention and control of rock engineering disasters is discussed. This new method theoretically expands the technology of rock mass structural plane identification and has important application value in practical engineering.

Characteristics structure of grain boundary plane in nanocrystalline Nd-Fe-B magnets

Characteristics structure of grain boundary plane in nanocrystalline Nd-Fe-B magnets

Stress modulation of hafnium-based ferroelectric material orientation in 3D cylindrical capacitor

Hafnium-based ferroelectric materials have attracted a lot of attention, but the distributions of the materials need to be tuned for commercialization, including phase distribution and polarization orientation distribution. The orientation of ferroelectric materials plays a significant role in memory device performance; however, there have been no reliable methods to control this orientation until now. This paper investigates the control of ferroelectric phase polarization orientation in 3D cylindrical capacitors. This optimization is made possible because the 3D cylindrical capacitor allows stress application in the tangential, axial, and radial directions, offering a wider range of adjustment options than 2D planar structures. The study focuses on how stress distribution affects ferroelectric phase orientation in hafnium-based materials when the diameters of cylindrical capacitors are varied. First, stress simulations are conducted to analyze the stress distribution in cylindrical capacitors with different diameters. The results indicate that the hafnium oxide layer experiences increased radical stress as the capacitor diameter decreases. Subsequently, capacitors with two different diameters are fabricated, significantly improving the polarization orientation in the thinner one. It is found that the capacitor diameter and the polarization orientation are strongly related through the correlation analysis. Finally, we demonstrate the improvement in the polarization orientation of ferroelectric thin films by radical stress through first-principles calculations. This study provides valuable insights into how stress distribution influences polarization orientation in hafnium-based ferroelectric films and is crucial for advancing the use of ferroelectric materials in future technologies.

Synthesis, antibacterial evaluation and in silico studies of novel 2-(benzo[d]thiazol-2-yl)-N-arylacetamides and their derivatives as potential DHFR inhibitors

Novel N-arylacetamides 2a–f were synthesized based on benzo[d]thiazole scaffold. The compounds 2a–c underwent Knoevenagel condensation through green synthetic method with different aromatic aldehydes and pyrazole-7-carbaldehydes delivered the respective arylidenes with efficient yields. Arylidenes 4 reacted with malononitrile affording the corresponding N-arylpyridones 11a–i. Moreover, the reaction of 2a–c with each of salicylaldehyde and 5-arylazo salicylaldehydes afforded the unexpected coumarins rather than quinolin-5-ones. The structure of coumarin 8 was confirmed by density functional theory (DFT) calculations using basis set B3LYP/6-311 G + + (d,p) to obtain the suitable geometrical structure with molecular orbitals` energies revealing its planar structure and its agreement with experimental data. Besides, the antibacterial activity was tested against different bacterial strains revealing potent activity especially Gram-negative bacteria with excellent minimum inhibition concentration (MIC) value ranging from 31.25 to 250 µg/L. Additionally, compounds 2c and 4m showed enzyme inhibition against dihydrofolate reductase in Escherichia coli with greater potency (IC50 for 2c = 3.796 µM, IC50 for 4m = 2.442 µM) than the standard antibiotic trimethoprim (IC50 = 8.706 µM). Investigation of the physicochemical properties of the newly compounds exhibited their better ADME properties that can be developed for the discovery of new antibacterial agents.Graphical

Similarities and Differences between ICME-driven Shocks Observed by VEX (∼0.72 au) and WIND (∼1.0 au)

Abstract The features of interplanetary shocks driven by interplanetary coronal mass ejections (ICMEs) observed by WIND (∼1.0 au) and Venus Express (VEX; ∼0.72 au) during the same period are statistically analyzed by comparing their similarities and differences. It is found that the proportion of ICME-driven shocks in all shocks decreases slightly from ∼0.72 to ∼1 au. The yearly occurrence of ICME-driven shocks at both ∼0.72 and ∼1 au roughly follows the sunspot cycle, while the magnetic field ratio does not show such a correspondence. In each year, the annual medians of the shock angle for ICME-driven shocks at ∼1 au are consistently larger than those at ∼0.72 au, and the annual medians of the magnetic field ratio for events at ∼1 au are slightly smaller than those at ∼0.72 au. Planar magnetic structures (PMSs) downstream of ICME-driven shocks are also analyzed. Approximately 28.57% of the detected PMS events from VEX observations and 28.84% from WIND observations cover the entire 2 hr intervals downstream of the shocks, which are referred to as full PMS events. Through comparative analysis for VEX and WIND observations, it is found that strong and quasi-perpendicular ICME-driven shocks are the most preferable conditions for full PMS formation.

Numerical investigation on seismic response characteristics and deformation mechanism of high-steep rock slopes containing weak structural planes using time-frequency joint analysis

Numerical investigation on seismic response characteristics and deformation mechanism of high-steep rock slopes containing weak structural planes using time-frequency joint analysis

Analytical Verification of the Normal Vector Determination Methods for Planar Magnetic Structures

Abstract Minimum variance analysis of magnetic fields (MVAB) is conventionally implemented to determine the normal vector of a planar magnetic structure (PMS) for which the average of the normal magnetic field component vanishes (i.e., B n = 0). A more suitable normal vector determination method for single-spacecraft measurements, based on the minimum variance concept, is recommended for PMS studies, namely the MVAB method associated with the constraint B n = 0 (MVABC). An analytical PMS model is employed to verify the performance of the MVAB and MVABC methods for three different types of PMSs, under the circumstances that the B n values are highly fluctuated but the B n remains zero. The results show that MVABC outperforms MVAB in estimating the PMS normal vector. By analyzing a large number of test data sets randomly selected from the original data set, the conclusion remains unchanged. The normal of a PMS discontinuity, which is associated with significant B n fluctuations, is accurately predicted by MVABC and the cross-product method, as compared to MVAB. Moreover, the normal of the discontinuity aligns with the PMS normal, as expected. Two PMS events observed by the Advanced Composition Explorer spacecraft in the sheath of an interplanetary coronal mass ejection are presented. From the MVAB perspective, these two events are not classified as PMSs. The estimated normals of the in situ PMS discontinuities from the cross-product method form angles between 10° and 20° with the predicted PMS normals from MVABC. Discussions are given regarding the failure of the MVAB method in PMS identification.

σ-Electrons rather than π-Electrons Inducing Sensitive Nonlinear Optical Responses in Planar and Quasi-Planar Boron Clusters.

Geometries and electronic structures of planar and quasi-planar boron clusters resemble those of aromatic hydrocarbons, providing opportunities for designing novel nonlinear optical materials. However, the nonlinear optical properties, optical-response mechanisms, and optimal optical-response geometries of boron clusters remain unclear. Accordingly, this study addresses these uncertainties. Boron clusters exhibit good nonlinear optical performance, significantly surpassing that of aromatic hydrocarbons of comparable size. An analysis method based on electron density decomposition is proposed to quantitatively determine the contributions of σ- and π-electrons to the optical responses. The findings reveal that σ-electrons dominate the nonlinear optical responses in planar boron clusters owing to their delocalized characteristics, in marked contrast to aromatic hydrocarbons. Using boron isomers as model systems, boron nanoribbons were confirmed to provide optimal nonlinear optical performances. This study offers valuable insights into the nonlinear optical behaviors of planar and quasi-planar boron clusters, substantially enhancing the rational design of novel nonlinear optical materials.

Self-Foldable Three-Dimensional Biointerfaces by Strain Engineering of Two-Dimensional Layered Materials on Polymers.

Two-dimensional layered materials (2DLMs) have received increasing attention for their potential in bioelectronics due to their favorable electrical, optical, and mechanical properties. The transformation of the planar structures of 2DLMs into complex 3D shapes is a key strategic step toward creating conformal biointerfaces with cells and applying them as scaffolds to simultaneously guide their growth to tissues and enable integrated bioelectronic monitoring. Using a strain-engineered self-foldable bilayer, we demonstrate the facile formation of predetermined 3D microstructures of 2DLMs with controllable curvatures, called microrolls. Three types of 2DLM microrolls─graphene, hexagonal boron nitride, and molybdenum disulfide─provide scaffolds to encapsulate and organize human-induced pluripotent stem cell-derived cardiomyocytes into tubular aggregates. Encapsulating cardiomyocytes in porous 2DLMs-laden microrolls allows for real-time microscopic observation and construction of precisely shaped cardiac tissues interacting with their surroundings. The ability to combine 2DLMs of diverse properties in the same structure further demonstrates the potential of this self-folding strategy for creating flexible, ultrathin bioelectronic devices that integrate seamlessly with complex biological environments, offering real-time, noninvasive monitoring of engineered tissues and organoids.