摘要：
Forming ohmic contacts between metals and semiconductors is critical to achieving high-performance and energy-efficient electronics. Here we investigate the interface properties of WSi2N4 contacted by Mo2B, O-modified Mo2B (Mo2BO2) and OH-modified Mo2B (Mo2B(OH)(2)) nanosheets using density functional theory simulations. We show that WSi2N4 and Mo2B form n-type Schottky contacts with barrier heights that are robust against external electric fields. In contrast, functionalizing Mo2B with O and OH causes the work function to energetically down- and up-shift significantly, thus forming both n-type and p-type ohmic contacts with WSi2N4, respectively. The possibility of achieving both p-type and n-type ohmic contacts immediately suggests the role of surface-engineered Mo2B as a key enabler towards WSi2N4-based complementary metal-oxide-semiconductor (CMOS) device technology in which both n-type and p-type devices are needed. We further demonstrate the emergence of quasi-ohmic contact with ultralow lateral Schottky barrier and zero vertical interfacial tunneling barriers in Mo2B(OH)(2)-contacted WSi2N4 - a feature rarely found in other 2D/2D metal/semiconductor contacts, thus demonstrating surface-engineered Mo2B as a promising electrode to WSi(2)N(4 )with high charge injection efficiency. These results offer design insights useful for the development of high-performance 2D semiconductor CMOS device technology.
摘要：
Cr3+ doped phosphors with deep -red luminescence hold great promise as artificial lighting sources for plants growth. Among them, alpha-Al2O3:Cr3+ is featured with an ultra -intense pure zero phonon line (ZPL) emission with negligible sidebands. Nonetheless, further enhancements in its luminescence thermal stability are required to fully unlock its potential for practical applications. To tackle this challenge, we propose that Al20B4O36 with a negative expansion coefficient could serve as a more favorable host materials for Cr3+ ion, thereby enhancing the luminescence thermal stability. Our first -principles calculations have unveiled similar electronic structures for alpha-Al2O3:Cr3+ and Al20B4O36:Cr3+, suggesting that the observed zero phonon R -line (2Eg) emission, arising from the 2Eg -> 4A2g transition in alpha-Al2O3:Cr3+, might also be present in Al20B4O36:Cr3+. Based on these findings, we prepared Al20B4O36:Cr3+ phosphors using a simple solid reaction method and confirmed that Al20B4O36:Cr3+ indeed exhibits a similar ultra -intense pure ZPL emission centered at 694 nm. Moreover, Al20B4O36:Cr3+ phosphors demonstrate remarkable properties including a high internal quantum efficiency (IQE) of 98.2 % and superior luminescence thermal stability compared to alpha-Al2O3:Cr3+. A phosphor converted light emitting diode (pc -LED) is developed by coating Al20B4O36:Cr3+ phosphor onto a near -ultraviolet LED chip. The lighting from this deep -red LED significantly impacts the photomorphogenesis of bean sprouts. Our study showcases a rational approach to design novel Cr3+ doped phosphors with enhanced luminescent properties, tailored for specific applications.
摘要：
The study delves into the behavior of cos-Gaussian breathers navigating through a highly nonlocal medium, with a spotlight on their width and intensity variations under different parameter adjustments. The mathematical formulas describing the characteristics of cos-Gaussian beams have been derived. By controlling the parameters, the transverse width of cos-Gaussian beams can exhibit various variations, reflecting various mode transformations. We scrutinized how alterations in cosine parameters, offset distance, and initial energy manifest in the breather's width and shape during propagation. Our observations underscore the significant influence of these parameters on the dynamic evolution and morphology of cos-Gaussian breathers, thereby unveiling the potential application of using parameters to control the dynamic characteristics of cos-Gaussian beam transmission.
摘要：
The transmission characteristics of circular-linear edge dislocation vortex (CLEDV) beams in optical nonlocal medium is investigated analytically and numerically in detail. The analytical expression for the transmission of CLEDV beams is derived, and the transmission characteristics of CLEDV beams are illustrated in figures. The influence of various parameters of CLEDV beams on transmission characteristics is discussed, including statistical spot size, input power, topological charge, etc. The results indicate that the main transverse intensity of CLEDV beams can maintain a crescent shaped distribution and rotate periodically under the influence of topological charges. For different input powers, the variations of the statistical spot size of CLEDV beams in two transverse directions exhibit diverse behaviors: they can be diametrically opposite, simultaneously expand or compress, remain constant in one direction while periodically changing in the other. This complexity highlights the intricate dynamics of CLEDV beams in optical nonlocal medium.
关键词：
eucalyptus plantation;sliding time window;LandTrendr;Google Earth Engine (GEE);historical dynamic
摘要：
Eucalyptus plantations are expanding rapidly in southern China owing to their short rotation periods and high wood yields. Determining the plantation dynamics of eucalyptus plantations facilitates accurate operational planning, maximizes benefits, and allows the scientific management and sustainable development of eucalyptus plantations. This study proposes a sliding-time-window change detection (STWCD) approach for the holistic characterization and analysis of eucalyptus plantation dynamics between 1990 and 2019 through dense Landsat time-series data. To achieve this, pre-processing was first conducted to obtain high-quality reflectance data and the monthly composite maximum normalized-difference vegetation index (NDVI) time series was determined for each Landsat pixel. Second, a sliding time window was used to segment the time series and obtain the NDVI change characteristics of the subsequent segments, and a sliding time window-based LandTrendr change detection algorithm was applied to detect the crucial growth or harvesting phases of the eucalyptus plantations. Third, pattern-matching technology was adopted based on the change detection results to determine the characteristics of the eucalyptus planting dynamics. Finally, we identified the management history of the eucalyptus plantations, including planting times, generations, and rotation cycles. The overall accuracy of eucalyptus identification was 90.08%, and the planting years of the validation samples and the planting years estimated by our algorithm revealed an apparent correlation of R2 = 0.98. The results showed that successive generations were mainly first- and second-generations, accounting for 75.79% and 19.83% of the total eucalyptus area, respectively. The rotation cycles of the eucalyptus plantations were predominantly in the range of 4-8 years. This study provides an effective approach for identifying eucalyptus plantation dynamics that can be applied to other short-rotation plantations.
摘要：
Glutamine dependence is a prominent feature of cancer metabolism and is essential for the growth of CT26 cells. The photobiomodulation of glutamine‐dependent CT26 cells inhibits cell apoptosis without increasing cell proliferation by regulating GLUT1, MEK/ERK, and PI3K/AKT/mTOR signals. The proliferation and apoptosis of CT26 cells with glutamine addiction are jointly completed by multiple signaling pathways. Abstract We investigated the mechanism of action of photobiomodulation (PBM) with light‐emitting diode (led) 640 nm of glutamine‐dependent CT26 cells. Cells were exposed to 0.147–10.979 mW/cm2 of 640 ± 15 nm laser light for 15 min/day for 10 days. Cell proliferation and apoptosis were detected by MTT (3‐(4,5)‐dimethylthiahiazo (‐z‐y1)‐3,5‐diphenytetrazoliumromide) and annexin V‐FITC assays. mRNA and protein levels of cell proliferation‐related genes were measured by RT‐PCR and western blotting, respectively. With Gln 7.94 mM, on Day 8 and 10, genes GLUT1, MEK1, ERK2, BCL2, E2F1, HO‐1, Ctnnb1, and Per2 was significantly upregulated (p < 0.01) of glutamine addiction. In PBM therapy, compared with the non‐illuminated group, 2.17 mW/cm2 can significantly reduce cell apoptosis, the mRNA level of gene mTOR1 was significantly upregulated, and the protein level of raptor of GLUT1 and mTOR1, MEK1/2, and ERK1/2 were upregulated. LED 640 nm inhibits cell apoptosis without increasing cell proliferation by regulating GLUT1, MEK/ERK, and PI3K/AKT/mTOR signals.
摘要：
Understanding how the electronic state of transition metal atoms can influence molecular adsorption on a substrate is of great importance for many applications. Choosing NH(3) as a model molecule, its adsorption behavior on defected SnS(2) monolayers is investigated. The number of valence electrons n is controlled by decorating the monolayer with different transition metal atoms, ranging from Sc to Zn. Density-Functional Theory based calculations show that the adsorption energy of NH(3) molecules oscillates with n and shows a clear odd-even pattern. There is also a mirror symmetry of the adsorption energies for large and low electron numbers. This unique behavior is mainly governed by the oxidation state of the TM ions. We trace back the observed trends of the adsorption energy to the orbital symmetries and ligand effects which affect the interaction between the 3σ orbitals (NH(3)) and the 3d orbitals of the transition metals. This result unravels the role which the spin state of TM ions plays in different crystal fields for the adsorption behavior of molecules. This new understanding of the role of the electronic structure on molecular adsorption can be useful for the design of high efficiency nanodevices in areas such as sensing and photocatalysis.
摘要：
Six aroylhydrazone di-m-chlorobenzyltin complexes {[X-C(6)H(4)(O)C=N-N=C(Me)COO](MeOH)(m-Cl-C(6)H(4)CH(2))(2)Sn}(2) (X = p-Me- (1), p-MeO- (2), p-t-Bu- (3), p-NO(2)- (4), p-OH- (5) or o-OH- (6)) were synthesized and characterized by HRMS (high-resolution mass spectrometry), NMR (nuclear magnetic resonance spectroscopy), IR (Fourier transform infrared spectroscopy), and TGA (thermogravimetric analysis) techniques. The molecular structure of complexes 1-6 was confirmed by single-crystal X-ray crystallography. The structure of complexes showed a distorted pentagonal bipyramidal configuration around the tin atom center, and the ligands adopted a tridentate chelating mode. Fascinatingly, either one-dimensional infinite chain structures or two-dimensional network structures were observed in the complexes through hydrogen bonds. Complex 2 has the strongest inhibitory effect on MCF7 and HepG2 cell proliferation, its effect was superior to that of the positive control drug cisplatin. The interaction of ct-DNA (calf-thymus DNA) with complex 2 was explored using UV absorption (ultraviolet absorption) and fluorescence spectroscopy. Complex 2 exhibited a moderate affinity for ct-DNA through intercalation modes. The interaction of complex 2 with ct-DNA has also been supported by molecular docking studies.
作者机构：
[Hu, JW; Zhai, Yunran; Cui, Ying; Hu, Jiawen] Hunan Univ, Coll Chem & Chem Engn, Adv Catalyt Engn Res Ctr, Hunan Key Lab Two Dimens Mat,Minist Educ, Changsha 410082, Peoples R China.;[Cui, Ying; Li, Junhua] Hengyang Normal Univ, Coll Chem & Mat Sci, Key Lab Funct Met Organ Cpds Hunan Prov, Hengyang 421001, Peoples R China.;[Fan, Shanji; Liu, Yingjie] Univ South China, Affiliated Hosp 1, Hengyang Med Sch, Dept Breast & Thyroid Surg, Hengyang 421000, Peoples R China.;[Wang, Lijia] Zhejiang Univ, Natl Clin Res Ctr Child Hlth, Natl Childrens Reg Med Ctr, Childrens Hosp,Sch Med, Hangzhou 310052, Zhejiang, Peoples R China.
通讯机构：
[Hu, JW ] H;[Wang, LJ ] Z;Hunan Univ, Coll Chem & Chem Engn, Adv Catalyt Engn Res Ctr, Hunan Key Lab Two Dimens Mat,Minist Educ, Changsha 410082, Peoples R China.;Zhejiang Univ, Natl Clin Res Ctr Child Hlth, Natl Childrens Reg Med Ctr, Childrens Hosp,Sch Med, Hangzhou 310052, Zhejiang, Peoples R China.
摘要：
This study reports a metal-enhanced fluorescence chemodosimeter for highly sensitive detection of Hg2+ ions. Silica-coated Au nanoparticles (Au@SiO2 NPs) with a pinhole-free 4-5 nm shell were synthesized and functionalized with a monolayer of turn-on fluorescent probes. Compared to other organic fluorescent probes suffering from poor biocompatibility and detection limits, this design of a monolayer of turn-on fluorescent probes immobilized on the Au@SiO2 NPs with a pinhole-free 4-5 nm shell avoids fluorescence quenching and allows the fluorescent probe within the field of the inner Au NPs to experience metal-enhanced fluorescence. With this design, the chemodosimeter permits fluorescence emission in the presence of Hg2+ ions, because they trigger the ring-opening reaction of the fluorescent probe immobilized on the Au@SiO2 NPs. Additionally, the fluorescent probe is distanced by the thin SiO2 shell from directly attaching to the metallic Au NPs, which not only avoids fluorescence quenching but allows the fluorescent probe within the long-ranged field of the inner Au NPs to experience metal-enhanced fluorescence. As a result, the detection limit for the chemodosimeter can reach up to 5.0 x 10(-11) M, nearly two orders of magnitude higher than that achieved for the free fluorescent probe. We also demonstrate the acquisition of images of Hg2+ in HTC116 cells and zebrafish using a simple fluorescence confocal imaging technique. The fluorescence response results for HTC116 cells and zebrafish show that the probes can permeate into cells and organisms. Considering the availability of the many organic fluorescent probes that have been designed, the current designed metal-enhanced fluorescence chemodosimeter holds great potential for fluorescence detection of diverse species and fluorescence imaging.
通讯机构：
[Zhao, HH ] H;Hengyang Normal Univ, Coll Comp Sci & Technol, Hengyang 421008, Peoples R China.
关键词：
Convex optimization;block compressive sensing;split Bregman iteration;Poisson function
摘要：
To improve reconstruction performance in imagery compressive sensing, the present paper changes solving a block image compressive sensing reconstruction into a convex optimization problem. First, a Total-Variation norm minimization constraints model that includes both L1 and L2 norm functions is established. The split Bregman iterative method solves the model with convex optimization. Then, a robust adaptive image block compressive sensing algorithm is studied based on an analysis of the image features. The image is divided into blocks, and an overlap image block compressive reconstruction method is proposed. Finally, to solve the block effect caused by block compressive sensing reconstruction, a novel image overlap block compressive sensing reconstruction based on the Poisson function is suggested to avoid the block effect in the reconstruction process. The experimental results show that compared with other traditional compressive sensing reconstruction algorithms, the proposed method can generate a better image reconstruction result. According to the PSNR evaluation, when the sampling rate is 0.3, the proposed method is improved by more than 20.98% compared to the conventional techniques, and according to the SSIM evaluation, it has improved by more than 11.92% from the traditional methods. We can also find that the proposed method has better construction effect for traffic sign image recognition compared with ordinary natural image reconstruction. When the sampling rate is only 0.1, the PSNR value reaches 44.28dB, and the SSIM reconstruction accuracy reaches 98.14%. After reconstructing different types and characteristic images, it is supported that the proposed algorithm has good robustness and anti-noise performance.
期刊：
JOURNAL OF ORGANIC CHEMISTRY,2024年89(5):2939-2950 ISSN：0022-3263
通讯作者：
Fu, Yang;Ding, QP
作者机构：
[Tan, Yuxing; Ding, Qiuping; Jiang, Wu-jiu; Fu, Yang; Ding, QP] Jiangxi Normal Univ, Key Lab Green Chem Jiangxi Prov, Key Lab Fluorine & Silicon Energy Mat & Chem, Minist Educ, Nanchang 330022, Jiangxi, Peoples R China.;[Tan, Yuxing; Jiang, Wu-jiu; Ni, Penghui] Hengyang Normal Univ, Coll Chem & Mat Sci, Key Lab Funct Met Organ Cpds Hunan Prov, Hengyang 421008, Hunan, Peoples R China.
通讯机构：
[Fu, Y; Ding, QP ] J;Jiangxi Normal Univ, Key Lab Green Chem Jiangxi Prov, Key Lab Fluorine & Silicon Energy Mat & Chem, Minist Educ, Nanchang 330022, Jiangxi, Peoples R China.
摘要：
Herein, we developed a highly selective, efficient, and simple method for direct transamidation of thioamides with amines, promoted by commercially available acetophenone under metal-/solvent-free conditions. The reaction tolerated a wide range of functional groups and substrates, including single- or double-thioamides, benzylamines, or alkyl/cycloalkyl-substituted aliphatic amines. The present protocol can be applied to gram-scale in good yields. In addition, the Pt-/Ni-complexes of double-transamidation products were obtained in good to excellent yields. The investigation of photophysical properties indicated that the fluorescence spectra of Pt-complexes showed an emission band centered at 550-750 nm and exhibited red fluorescence when irradiated by a UV lamp (365 nm).
