• Book : 215()
• Pub. Date : 2025
• Page : pp.111561
• Keyword :

Abstract

Developing advanced stealth devices to cope with radar-infrared (IR) fusion detection and diverse application scenarios is increasingly demanded, which faces significant challenges due to conflicting microwave and IR cloaking mechanisms and functional integration limitations. Here, we propose a multiscale hierarchical structure design, integrating wrinkled MXene IR shielding layer and flexible Fe3O4@C/PDMS microwave absorption layer. The top wrinkled MXene layer induces the intensive diffuse reflection effect, shielding IR radiation signals while allowing microwave to pass through. Meanwhile, the permeable microwaves are assimilated into the bottom Fe3O4@C/PDMS layer via strong magneto-electric synergy. Through theoretical and experimental optimization, the assembled stealth devices realize a near-perfect stealth capability in both X-band (8-12 GHz) and long-wave infrared (8-14 µm) wavelength ranges. Specifically, it delivers a radar cross-section reduction of − 20 dB m², a large apparent temperature modulation range (ΔT = 70 °C), and a low average IR emissivity of 0.35. Additionally, the optimal device demonstrates exceptional curved surface conformability, self-cleaning capability (contact angle ≈ 129°), and abrasion resistance (recovery time ≈ 5 s). This design strategy promotes the development of multispectral stealth technology and reinforces its applicability and durability in complex and hostile environments.

• Book : 17(1)
• Pub. Date : 2025
• Page : pp.40
• Keyword :

• Book : 217()
• Pub. Date : 2025
• Page : pp.29-46
• Keyword :

Abstract

Radiative cooling materials (RCMs) based on polymers, which reflect solar irradiance (0.24-2.5 μm) strongly and emit radiation within atmospheric window (8-13 μm) intensively, have yielded obvious cooling performance. However, RCMs reported failed to realize high mid-wave infrared (2.5-8 μm) reflectance (i.e., spectral selectivity), which play an important role in rejecting the radiation from the ambient, especially in high relative humidity. Thus, enhancing the reflectance of RCMs in mid-wave infrared can further strengthen the cooling effect in an environment of high relative humidity. The additive of fillers with high reflectance in mid-wave infrared is effective, low cost, and convenient to modify the cooling performance of polymeric RCMs. In this article, micron rectangular bismuth oxychloride (BiOCl) powders were proposed and synthesized using the hydrothermal method. Rectangular BiOCl boasts excellent mid-wave infrared reflective capacity (85%). Then, rectangular BiOCl was added into the top layer of flexible hierarchically porous complex membrane and improved the reflectance of porous membrane within 2.5-8 μm from 48.3% to 58.1%. However, the emittance of the obtained bilayer membrane within the atmospheric window was hardly affected. The membrane with BiOCl exhibited better cooling performance in humid ambient (70%), demonstrating the importance of spectral selectivity experimentally. This work proposed an effective strategy to modify the spectral selectivity of RCMs, and it could expand the application of radiative cooling materials in hot and humid areas.

• Book : 147(2)
• Pub. Date : 2025
• Page : pp.024501
• Keyword :

• Book : 56(1)
• Pub. Date : 2025
• Page : pp.101781
• Keyword :

• Book : 425()
• Pub. Date : 2025
• Page : pp.116339
• Keyword :

Abstract

Purpose

To demonstrate the feasibility of 3D echo‐planar spectroscopic imaging (EPSI) technique with rapid volumetric radial k‐space sampling for hyperpolarized (HP) ¹³C magnetic resonance spectroscopic imaging (MRSI) in vivo.

Methods

A radial EPSI (rEPSI) was implemented on a 3 T clinical PET/MR system. To enable volumetric coverage, the sinusoidal shaped readout gradients per k‐t‐spoke were rotated along the three spatial dimensions in a golden‐angle like manner. A distance‐weighted, density‐compensated gridding reconstruction was used, also in cases with undersampling of spokes in k‐space. Measurements without and with HP ¹³C‐labeled substances were performed in phantoms and rats using a double‐resonant ¹³C/¹H volume resonator with 72 mm inner diameter.

Results

Phantom measurements demonstrated the feasibility of the implemented rEPSI sequence, as well as the robustness to undersampling in k‐space up to a factor of 5 without advanced reconstruction techniques. Applied to measurements with HP [1‐¹³C]pyruvate in a tumor‐bearing rat, we obtained well‐resolved MRSI datasets with a large matrix size of 12³ voxels covering the whole imaging FOV of (180 mm)³ within 6.3 s, enabling to observe metabolism in dynamic acquisitions.

Conclusion

After further optimization, the proposed rEPSI method may be useful in applications of HP ¹³C‐tracers where unknown or varying metabolite resonances are expected, and the acquisition of dynamic, volumetric MRSI datasets with an adequate temporal resolution is a challenge.

• Book : 93(1)
• Pub. Date : 2025
• Page : pp.31-41
• Keyword :

• Book : 4(1)
• Pub. Date : 2025
• Page : pp.100140
• Keyword :

Weather is one of the important elements that greatly determines human activities, especially those related to economic factors. Therefore, understanding weather conditions using weather parameters as a reference is important for human life, so a method is needed to classify weather according to its category so that the information produced can be used for various needs. Determining weather conditions in an area will not run well without a reliable method that can analyze existing weather parameters. Therefore, in this study, the weather condition classification process was carried out using the multilayer perceptron algorithm, a type of neural network (NN) algorithm. All data analyzed were weather parameter data collected by mini weather stations placed on land. The weather parameters used were temperature, humidity, air pressure, wind speed, dew point, wind chill, daily rainfall, solar radiation, and UV index. This study was conducted in Palu city, Central Sulawesi Province, Indonesia. The classification process carried out by the multilayer perceptron algorithm was carried out on the Altair AI Studio application and produced an accuracy value of 93.87%, recall of 92.33%, and precision of 91.29%.

• Book : 37(1)
• Pub. Date : 2025
• Page : pp.540
• Keyword :

This research is on analysis of the stacked truncated microstrip patch for WLAN applications. The total size of 20 mm × 20 mm × 3.2³ mm. The same height and different dielectric constants are proposed in this design. For the improvement of the antenna required parameters, the basic microstrip is truncated at the edges. Then after shaped slots are etched from the active patch. The proposed stacked design uses RT5880 as the bottom substrate with a height of 1.6 mm and FR-4 as the upper substrate with a height of 1.6 mm to improve gain and low return loss. The proposed antenna is designed with a truncated microstrip patch with a proximity feeding technique. The microstrip feed line is on the bottom of this stacked design, and the radiating patch is on the upper substrate. The proposed antenna has a two-layered substrate where the patch element is on the top substrate and a microstrip feed line on the bottom substrate. The operating frequency of the proposed design is 5.6 GHz. The operating bandwidth is from 5.3 GHz to 5.7 GHz. Computer Simulation Technology Microwave Studio (CSTMW) 2018 was used to generate the simulation results. The benefits of this proposed design include its simple structure and small size. The other important parameters of the system, such as radiation pattern, directivity, VSWR, and reflection coefficient, are also simulated and discussed. The simulated results of the reflection coefficient are -42 dB, VSWR is less than 2, gain is 5.43 dB. According to the simulation results, this structure is well suited for WALN applications.

• Book : 84(1)
• Pub. Date : 2025
• Page : pp.1-8
• Keyword :