Jilin University

Bauxite plays a crucial role in metallic and non-metallic industry. The surface-exposed salento-type bauxite deposits have been largely exploited and developed. With the increasing demand of these resources, it is important but very challenging to explore the potential bauxite deposits in the deep earth. In this paper, based on new developments in transient electromagnetic (TEM) technologies, we conducted explorations of the sedimentary bauxite in Dengli-Tianyanggumei and Dajia mining areas in western Guangxi province. To achieve a fast and high-resolution inversion, we adopt an array-based observation strategy for large-scale 3-D TEM and collect EM data inside and outside the transmitting loop. Compared to traditional TEM surveys, the observation strategy can quickly acquire the data for large-scale surveys and improve the data acquisition efficiency by more than 25 times. We then use a 3-D inversion algorithm to estimate the underground conductivity structure and analyze the distribution of the sedimentary bauxite. To do that, we discretize the undulating surface and transmitter-receiver locations with unstructured grids and employ the finite-element and quasi-Newton methods to achieve high-resolution imaging of subsurface electrical structures. Since the observation strategy greatly reduces the number of transmitters, the efficiency of 3-D EM inversions can be significantly improved. Experiments over two mining areas show that our inversions can clearly recover the underground resistivities. The inferred burial depth and spatial distribution of the sedimentary bauxite are in agreement with the drilling data. By combining ERT results and geological data, we illustrate the impact of faults on the spatial distribution of potential sedimentary bauxite deposits.

Oxygen is ubiquitous and vital to life, industry, and environmental safety, so accurate and reliable oxygen sensing and detection are of great significance, especially for oxygen in the low concentration range. Herein, two pure organic metal‐free room‐temperature phosphorescence (RTP) materials were developed using a covalent trimerization strategy of thianthrene (TA), which exhibit high oxygen sensitivity and fluorescence‐RTP separated dual emission due to the moderate spin‐orbit coupling (SOC). Compared with traditional metal‐organic complexes, the oxygen sensitivity of RTP is improved by about two orders of magnitude, especially facilitating accurate quantitative detection of low‐concentration oxygen. Leveraging oxygen quenching‐induced changes in emission color and intensity, coupled with computer‐assisted image processing, a simple oxygen monitoring device was established to realize real‐time and accurate detection of low‐concentration oxygen, promoting the industrial practical application in many related fields.

2D covalent organic frameworks (2D‐COFs) have garnered huge attention as a promising platform for solar to chemical energy conversion. In this work, two novel azadiene‐linked COFs (COF‐JLU236 and COF‐JLU237) were designed and successfully synthesized under solvothermal conditions for the first time. And new materials have high crystallinity, large surface area, good durability, and broad absorption range, as well as excellent photoelectric properties. Importantly, they can effectively induce selective oxidation of sulfides and phenylboronic acids under visible light, and show wide substrate adaptability and superior reusability.

Multiple resonance thermally activated delayed fluorescence (MR‐TADF) emitters are promising candidates for ultra‐high‐definition organic light‐emitting diodes (OLEDs) displays. Here, we propose a general strategy for post‐functionalizing MR core, introducing donors on the lowest unoccupied molecular orbital (LUMO) position via Suzuki coupling and then fusing the donors to the highest occupied molecular orbital (HOMO) position via Scholl cyclization, which can extend frontier molecular orbitals delocalization to construct long‐wavelength narrowband emitters. Two proof‐of‐concept molecules, BN‐PhAzCz and BN‐tCzAzPh, are constructed, achieving large spectral red‐shifts while maintaining narrowband emission. The distorted configuration resulting from the hetero[6]helicene structure introduces twisted π–π* transition, which effectively enhances spinorbit coupling, ultimately enabling molecule BN‐PhAzCz to achieve a fast reverse intersystem crossing rate (kRISC = 6.4 × 104 s⁻¹). BN‐PhAzCz‐based single‐host OLED exhibits green emission at 528 nm with Commission Internationale de L'Eclairage (CIE) coordinates of (0.26, 0.69) and maximum external quantum efficiency (EQE) of 38.2% with efficiency roll‐off of 28.0% at 1000 cd m⁻² under 5 wt% doping concentration. Even at 20 wt% doping concentration, the maximum EQE remains at 29.6% with little change in the spectral profile.

Driven by the demand for high‐throughput data transmission, the development of cost‐effective and highly sensitive photoconductive photodetectors has become imperative to advance optical communication systems, thereby playing a crucial role in the realm of human–machine interaction. This study presents a β‐Ga2O3 photoconductive photodetector employed in an anti‐interference optical human–machine interaction system that demonstrates superior responsivity and minimized dark current, attributed to the strategic modulation of intrinsic defects. Through first‐principles simulations, the defect dynamics across various growth conditions are systematically elucidated, enabling the precise synthesis of β‐Ga2O3 films with markedly diminished shallow‐donor gallium interstitials. A super low dark current of 4.15 × 10⁻¹² A is achieved even under 40 V bias, accompanied by high responsivity of 2.26 A·W⁻¹ and superior detectivity realizing of 1.14 × 10¹⁴ Jones. Ultimately, β‐Ga2O3 photodetector is employed in human–machine interaction systems for robot arm control, which enables the system to demonstrate excellent resistance to random noise, which facilitates the integration of more efficient algorithms. Consequently, the system achieves an 88.46% reduction in reading time and a 78.17% reduction in required storage space, thereby demonstrating the substantial potential of cost‐effective, highly sensitive β‐Ga2O3 in the era of the Internet of Things.

In the microelectronics era, electromagnetic radiation and heat accumulation in electronic devices are urgent challenges requiring solutions, particularly through the use of structure‐function integrated and lightweight materials for electromagnetic interference (EMI) shielding and thermal management. Hierarchically structured polyether‐ether‐ketone‐based composites are prepared in this study by in situ deposition and dip coating using a simple and scalable method. Magnetic cobalt nanoparticles derived from magnetic metal–organic frameworks are deposited on carbon fiber felt featuring a macroscopic continuous conductive network. Next, a hybrid slurry is applied to connect the isolated fibers, which bridge the fiber gaps to create new electron and phonon transport channels, increasing the thermal conductivity (23.43 W m⁻¹ K⁻¹ in plane, 4.84 W m⁻¹ K⁻¹ through plane) for efficient heat dissipation. Owing to the stable 3D crosslinked network with high electrical conductivity (13 608 S m⁻¹), the composite offers ultra‐high EMI shielding in the X‐band (101.64 dB with stability in extreme environments), excellent Joule heating performance (220 °C at 4 V), and excellent photothermal conversion (94 °C at 500 mW cm⁻²). This multifunctional composite material has great application prospects in precision electronic equipment.