A facile approach to soluble star-shaped oligothiophene-functionalized polycyclic aromatics based on truxene is developed in this Communication. The Suzuki coupling reactions afford the thiophene-containing with long branches (about 2.1 nm length from heart periphery) precursor excellent yields. unsubstituted α-positions of thiophene rings allow for efficient halogenation and further functionalization. investigation proton NMR spectra indicates that hexahexyl groups efficiently prevent...

The structural information of offshore oil production equipment is the basis for functional modification and upgrading drilling platforms. In order to solve problems low efficiency in process acquiring structure by traditional measurement methods, we propose a deep learning-based point cloud data processing scheme equipment. First, dataset learning constructed, network based on two-step downsampling method local feature aggregation each after implemented semantic segmentation dataset....

The largest pi-conjugated dendrimers containing up to nine 10,15-dihydro-5H-diindeno[1,2-alpha;1',2';-c]fluorene (truxene) moieties have been prepared with good yields by repetitive Friedel-Crafts acetylation and acid-promoted cyclotrimerization reactions. An alternative approach the convergent synthesis of desired has developed, in which core is generated "in-situ" cyclotrimerizations aryl methyl ketones. This proves valuable afford large-size precisely well-defined an accelerated...

A convenient approach to a series of star-shaped π-conjugated organic materials with oligofluorenes (OF) as the branches and benzene ring core has been developed. The optical properties these are liable be tuned by introduction more fluorene rings. investigation structure−property relationship indicated differences between linear oligofluorenes, well polyfluorenes.

A series of well-defined 9,9'-dihexylfluorene-co-fluorenone copolymers with various fluorenone contents and a set monodisperse oligofluorenes in the chain center have been developed through palladium-catalyzed Suzuki coupling reaction. The structure−property relationships, especially effect moieties on photophysical electroluminescent properties these materials, are systematically investigated to elucidate exact origin low-energy emission polyfluorenes. On basis our substantial studies...

The accurate semantic segmentation of point cloud data is the basis for their application in inspection extra high-voltage transmission lines (EHVTL). As deep learning evolves, point-wise-based neural networks have shown great potential EHVTL clouds. However, are characterized by a large volume and significant class imbalance. Therefore, down-sampling method feature extraction used current hardly meet needs computational accuracy efficiency. In this paper, we proposed two-step based on local...

Multispectral methods for remote sensing image have been widely applied to shallow water bathymetry by researchers. In nonideal conditions, even with the same spectral radiance, points still a very wide range of depths. This means that features alone are insufficient bathymetry. Hence, we need extract other valuable from image. letter introduces spatial feature using images. We propose model utilizes multilayer perceptron (MLP) integrate and location features. Experimental results...

Two series of novel alternating polyfluorene copolymers containing 10,15-dihydro-5H-diindeno[1,2-α;1',2'-c]fluorene (truxene) moiety have been prepared through the Pd(0)-catalyzed Suzuki polymerization. The structure and purity desired polymers is fully characterized by 1H 13C NMR, UV−vis, photoluminescent spectroscopy, gel permeation chromatography, elemental analyses, TGA/DSC. absorption PL spectra all both in solutions thin films exhibit similar behaviors. For example, solutions, peak at...

Abstract Gravity anomalies (GAs) and vertical gravity gradient (VGGs) are regularly used to predict bathymetry. However, few studies have explored the combination of GAs VGGs We introduce back propagation (BP) neural network into bathymetric prediction field propose a method depth from VGGs. The was tested in Mariana Trench region, bathymetry model constructed using feature data obtained as input BP network. Additionally, single‐beam sounding were label data. By comparing gravity‐geologic...

Oligothiophene-functionalized 9,9'-spirobifluorene derivatives exhibit good solubility in polar organic solvents, especially compounds 5a-d to 7a-d due the introduction of flexible n-hexyl chain. The structures all studied are characterized and verified by (1)H (13)C NMR spectra. results not only show that these conjugated materials with no substituents or successfully synthesized through corresponding synthetic methodologies, but also prove chemical shifts protons carbons aromatic range...

In this study, to meet the need for accurate prediction of sea level anomaly (SLA), a hybrid model is proposed. model, empirical mode decomposition combined with singular spectrum analysis and least-squares extrapolation predict satellite-derived SLA. Each intrinsic function series an decomposed reconstructed using analysis. The components residual are predicted extrapolation. This was used SLAs that were obtained multi-mission along-track satellite altimetry data from September 1992 January...

Calibration/Validation (Cal/Val) of satellite altimeters is fundamental for monitoring onboard sensor performance and ensuring long-term data quality. As altimeter technology has been evolving rapidly from profile to wide swath interferometric altimetry, different requirements regarding Cal/Val have emerged. Most current developed conventional altimeters, whereby observations are compared against measurements at one point along orbit lines. However, the application this type technique with...

Shallow-water depth information is essential for ship navigation and fishery farming. However, the accurate acquisition of shallow-water has been a challenge marine mapping. Combining Ice, Cloud, Land Elevation Satellite-2 (ICESat-2) bathymetry data with multispectral data, satellite-derived promising solution through which to obtain bathymetric quickly accurately. This study proposes photon refraction correction method considering sea-surface undulations address errors in underwater photons...

The multi-beam echo sounder system can not only obtain high-precision seabed bathymetry data, but also high-resolution backscatter strength data. A number of studies have applied acoustic remote sensing method to classify sediment type with and obtained better classification results than the traditional sampling method. However, these mainly focus on single or mixed using beam Based data by a high-frequency (300 kHz) Simrad EM3000 Jiaozhou Bay in Qingdao, China, we establish relation model...

This paper proposed an MSC-Transformer model based on the Transformer’s neural network, which was applied to seabed sediment classification. The data came from about 2900 km2 of area northern slope South China Sea. Using submarine backscattering intensity and depth obtained by sub-bottom profiler, combined with latitude longitude information, a dataset Sea constructed. Moreover, using MSC-Transformer, accurate identification judgment types such as calcareous bio-silt, bio-clay silt, silty...

Sea ice type is one of the most sensitive variables in Arctic sea monitoring, and it important for retrieval thickness. In this study, we analyzed various waveform features that characterize echo shape Sigma0 (i.e., backscatter coefficient) CryoSat-2 synthetic aperture radar altimeter data over different types. Antarctic Research Institute operational charts were input as reference. An object-based random forest (ORF) classification method proposed with overall accuracy 90.1%. Accuracy 92.7%...

Shore zone information is essential for coastal habitat assessment, environmental hazard monitoring, and resource conservation. However, traditional classification mainly relies on in situ measurements expert knowledge interpretation, which are costly inefficient. This study classifies a shore area using satellite remote sensing data only investigates the effect of statistical indicators from Ice, Cloud, Land Elevation Satellite-2 (ICESat-2) with Sentinel-2 data-derived spectral variables...

In the past decade, synthetic aperture radar interferometry (InSAR) technique has been extensively employed in deltas, making it possible to obtain more subsidence signals. However, spatiotemporal nonlinearity of land often results inaccurate estimations. Based on 72 Sentinel-1A images captured from 2016 2021 and time-series persistent scatterer-interferometric SAR (PS-InSAR) method, we comprehensively analyze temporal spatial dynamics recent Yellow River Delta (YRD). The findings suggest a...