Articoli di riviste: "Stealth material"

1

Luo, Ziyin, Qizheng Zhou e Peng Guo. "Microstructure Design and Performance Optimization of Constant Modulus Pentamode Materials Acoustic Cloak". Crystals 12, n. 11 (4 novembre 2022): 1572. http://dx.doi.org/10.3390/cryst12111572.

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Underwater acoustic stealth has great scientific research value. According to acoustic coordinate transformation theory, the acoustic stealth cloak based on pentamode materials can realize underwater broadband acoustic stealth. However, due to the correlation between the density and modulus of pentamode materials and the changes in the parameters of each layer of the acoustic stealth cloak, a large amount of structural optimization work is required for the pentamode material to meet the specific parameter requirements, which significantly increases the difficulty of the pentamode acoustic stealth cloak design. To simplify the design process, inspired by the calculation of equivalent modulus by representation volume element, this article proposed a pentamode material configuration with independent variation of density and modulus and designed a 1 m radius acoustic stealth cloak with a specific structure of pentamode materials matching the coordinate transformation equation of constant modal mapping. After simulation calculation and optimization design, in the range of a/λ from 0 to 1, the average total scattering cross-section of the cavity with a radius of 0.5 m covered by the acoustic stealth cloak is 0.858; the average total scattering cross-section of the cavity is 19.718 after removing the pentamode material acoustic stealth cloak. The results of the study are expected to provide some method references for simplifying the design process of the pentamode material acoustic stealth cloak and the microstructure design of the pentamode materials.

2

Zhang, Zhixun, Mingyang Yang, Yibo Zhang e Ming Zhou. "Research and Application of Terahertz Response Mechanism of Few-Layer Borophene". Nanomaterials 12, n. 15 (5 agosto 2022): 2702. http://dx.doi.org/10.3390/nano12152702.

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The terahertz stealth and shielding performance of a new type of two-dimensional material, borophene, has been studied theoretically and experimentally. Studies have shown that borophene materials have good terahertz stealth and shielding properties. First-principles calculations show that compared with single-layer borophene, few-layer borophene has good terahertz stealth and shielding performance in the range of 0.1~2.7 THz. In the range of 2~4 layers, the terahertz stealth and shielding performance of few-layer borophene increases with the increase of the number of layers. The finite element simulation calculation results also confirmed this point. Using the few-layer borophene prepared by our research group as a raw material, a PDMS composite was prepared to verify the terahertz stealth and shielding performance of the few-layer borophene. In the ultra-wide frequency range of 0.1~2.7 THz, the electromagnetic shielding effectiveness (EMI SE) of the PDMS material mixed with few-layer borophene can reach 50 dB, and the reflection loss (RL) can reach 35 dB. With the concentration of few-layer borophene increasing, the terahertz stealth and shielding effectiveness of the material is enhanced. In addition, the simultaneous mixing of few-layer borophene and few-layer graphene will make the material exhibit better terahertz stealth and shielding performance compared with mixing separately.

3

Wu, Yacong, Jun Huang, Mingxu Yi e Chaopu Zhang. "Simulation of active cancellation system based on N-order SSC algorithm". Aircraft Engineering and Aerospace Technology 91, n. 7 (8 luglio 2019): 949–60. http://dx.doi.org/10.1108/aeat-08-2017-0190.

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Purpose The purpose of this paper is to introduce the theoretical basis of N-order spectral spreading-compressing (SSC) frequency shift interference algorithm and expand it to active cancellation. An active cancellation simulation and verification system based on N-order SSC algorithm is established and carried out; simultaneously, the absorbing material coating stealth simulation of two kinds of thickness is carried out to compare the stealth effect with active cancellation system. Design/methodology/approach The active cancellation method based on N-order SSC algorithm is proposed based on theoretical formula derivation; the active cancellation simulation and verification system is established in MATLAB/Simulink. The full-size model is built by CATIA and meshed by hypermesh. The omnidirectional radar cross section (RCS) is calculated in cadFEKO, and the results are analyzed in postFEKO. Findings The simulations are implemented on a stealth fighter, and results show that after active cancellation, the peak of spectrum analyzer has reduced in all azimuths, the omnidirectional RCS has also decreased and the detection probability of almost all azimuths has dropped under 50 per cent. The absorbing material coating stealth simulations of two kinds of thickness are carried out, and results show that the stealth effect of active cancellation is much better than absorbing material coating. Practical implications An active cancellation system based on SSC algorithm is proposed in this paper, and the effect of active cancellation is verified and compared with that of absorbing materials. A new method for the current active stealth is provided in this paper. Originality/value Active cancellation simulation and verification system is established. RCS calculation module, signal-to-noise-ratio (SNR) calculation module and detection probability module are built to verify the effect of active cancellation system. Simultaneously, the absorbing material coating stealth simulation is carried out, and the stealth effect of absorbing material coating and active cancellation are compared and analyzed.

4

Irani, Afshad J., e Le (Emily) Xu. "Do stealth restatements convey material information?" Accounting Research Journal 24, n. 1 (19 luglio 2011): 5–22. http://dx.doi.org/10.1108/10309611111148751.

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Liu, Hua Wu, Fan Jie Chu, Zong Bin Yang e Hong Ming Dai. "Igneous Fiber Reinforced Stealthy Armor for Submarine". Advanced Materials Research 332-334 (settembre 2011): 1955–58. http://dx.doi.org/10.4028/www.scientific.net/amr.332-334.1955.

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Abstract: Igneous gem is a modified mineral glass without devitrification during processing, which is far stronger than traditional basalt materials comprising both glass and crystal phases. Fiber made by igneous gem is an ideal reinforcement for the armor of submarine, with advantages such as infrared stealth (thermal insulation), sonar stealth (anti-vibration), radar stealth (transparent to radar wave), heavy duty anticorrosion, bullet-proof (theoretical tensile strength 15,000MPa), fire resistant (working temperature 910 oC) and ultralow temperature resistant (working temperature up to -269 oC), anti-aging and so on. The corresponding experimental data and mathematical models were demonstrated in this study and compared with other high performance materials. The honeycomb structure was proposed for the prefabricated composite and the advantages of such a material were thoroughly stated.

6

Xu Wen-Lan, Zhang Shuan-Qin e Xu Yi. "The design of visible light stealth material". Acta Physica Sinica 53, n. 9 (2004): 3215. http://dx.doi.org/10.7498/aps.53.3215.

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S.P.Mishra, G. Nath e P. Mishra. "Synthesis and analysis of microwave stealth material". Materials Today: Proceedings 24 (2020): 585–90. http://dx.doi.org/10.1016/j.matpr.2020.04.312.

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8

Yayun Cheng, Yayun Cheng, Fei Hu Fei Hu, Feng He Feng He, Liang Wu Liang Wu e and Xiaoqin He and Xiaoqin He. "Millimeter-wave emission characteristics of bilayer radar-infrared compound stealth material". Chinese Optics Letters 14, n. 6 (2016): 062802–62806. http://dx.doi.org/10.3788/col201614.062802.

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9

Shi, Tao, Zhiheng Zheng, Huan Liu, Dezhen Wu e Xiaodong Wang. "Configuration of Multifunctional Polyimide/Graphene/Fe3O4 Hybrid Aerogel-Based Phase-Change Composite Films for Electromagnetic and Infrared Bi-Stealth". Nanomaterials 11, n. 11 (12 novembre 2021): 3038. http://dx.doi.org/10.3390/nano11113038.

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Electromagnetic (EM) and infrared (IR) stealth play an important role in the development of military technology and the defense industry. This study focused on developing a new type of multifunctional composite film based on polyimide (PI)/graphene/Fe3O4 hybrid aerogel and polyethylene glycol (PEG) as a phase change material (PCM) for EM and IR bi-stealth applications. The composite films were successfully fabricated by constructing a series of PI-based hybrid aerogels containing different contents of graphene nanosheets and Fe3O4 nanoparticles through prepolymerizaton, film casting, freeze-drying, and thermal imidization, followed by loading molten PEG through vacuum impregnation. The construction of PI/graphene/Fe3O4 hybrid aerogel films provides a robust, flexible, and microwave-absorption-functionalized support material for PEG. The resultant multifunctional composite films not only exhibit high microwave absorption effectiveness across a broad frequency range, but also show a good ability to implement thermal management and temperature regulation under a high latent-heat capacity of over 158 J/g. Most of all, the multifunctional composite films present a wideband absorption capability at 7.0–16.5 GHz and a minimum reflection loss of −38.5 dB. This results in excellent EM and IR bi-stealth performance through the effective wideband microwave absorption of graphene/Fe3O4 component and the thermal buffer of PEG. This study offers a new strategy for the design and development of high-performance and lightweight EM–IR bi-stealth materials to meet the requirement of stealth and camouflage applications in military equipment and defense engineering.

10

Sun, Hui Min, Ming Xue Zhang e Zhao Zhan Gu. "Study on Radar Absorbing Properties of Impure Sm₂O₃/Acrylate Coatings". Advanced Materials Research 849 (novembre 2013): 242–47. http://dx.doi.org/10.4028/www.scientific.net/amr.849.242.

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The development and application of the stealth material technology are one of the key factors to develop the stealth technology. The painting type of stealth material has the properties of simply process, usableness and easy regulate, so it has been extensive concern. In the paper the impure Sm2O3/acrylate coatings were prepared using Sm2O3 and carbon nanotubes powder and their microstructure was studied by SEM. Furthermore it was studied on radar absorption properties in 1-18GHz and mechanics properties of the coatings. It is proved that the absorption effect of the coatings is the best when the thickness coating is 1.2mm and its solid dosage is 50wt%. Meanwhile mechanics properties of the films are very good.

11

Lu, Shaoze, Jun Huang e Mingxu Yi. "Study on zonal coating design of absorbing material for a stealth helicopter". Aircraft Engineering and Aerospace Technology 92, n. 7 (1 giugno 2020): 1011–17. http://dx.doi.org/10.1108/aeat-01-2020-0004.

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Purpose By reducing the coating thickness of the weak scattering source, the coating weight of the absorbing material can be reduced by 35% with little effect on the RCS. Design/methodology/approach To alleviate the weight-increasing problem caused by a large number of coating of absorbing materials, a method for zonal coating of absorbing materials for a stealth helicopter was proposed. By appropriately reducing the thickness of the coating at the secondary scattering locations, the amount of coating used is significantly reduced. Findings Compared with the full-coated, the zonal coating scheme achieves the corresponding RCS reduction effect. Practical implications Zonal coating design can achieve the effect of reducing coating weight and cost. Originality/value The effects of different coating methods on RCS were verified by electromagnetic scattering simulation, and the applicability of the zonal coating design of the absorbing material to the stealth helicopter was verified.

12

Lu Ai-Jiang. "SiBN ceramics, a stealth material at high temperature". Acta Physica Sinica 62, n. 21 (2013): 217101. http://dx.doi.org/10.7498/aps.62.217101.

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13

Lee, Yongwoo, Injoong Chang, Juyeong Nam, Hyung Mo Bae e Hyung Hee Cho. "Analysis on Infrared Stealth Performance of Metal Nano-coating on Radome Surface". Journal of the Korea Institute of Military Science and Technology 25, n. 3 (5 giugno 2022): 251–58. http://dx.doi.org/10.9766/kimst.2022.25.3.251.

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Infrared stealth technology used in aircraft is applied to reduce the infrared signal by controlling surface temperature and emissivity using internal heat sink, low emissivity material or metamaterial. However, there is one part of the aircraft where the use of this technology is limited, and that is the radome. Especially, radome should have transmittance for the specific radio frequency, therefore, common stealth technology such as emissivity control surfaces cannot be applied to radome surface. In this study, we developed metal nano-coating for infrared stealth which is applicable to radome surface. We designed slot-type pattern for frequency selective transmission in X-band, and also controlled thickness of metal nano-coating for long wavelength infrared emissivity control. As a result, our infrared stealth surface for radome has 93.2 % transmittance in X-band and various infrared emissivities from 0.17 to 0.57 according to nano-coatings thickness. Also, we analyzed infrared signature of radome through numerical simulation, and finally reduced contrast radiant intensity by 97.57 % compared to polyurethane surface.

14

Jang, Jae-Kyeong, Jong-Min Hyun, Dae-Sung Son e Jung-Ryul Lee. "Nondestructive and electromagnetic evaluations of stealth structures damaged by lightning strike". Journal of Intelligent Material Systems and Structures 30, n. 17 (12 luglio 2019): 2567–74. http://dx.doi.org/10.1177/1045389x19862366.

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Stealth technology is very important for the survival of military aircraft. A stealth aircraft structure has both electromagnetic and mechanical functions. Lightning can cause failure on both the points. In this study, we claim that the stealth structure should be evaluated nondestructively and electromagnetically, and we propose a method for full-field evaluations of both the functions. First, a radar absorbing structure was designed and fabricated with stealth capability in the X-band. The radar absorbing structure consisted of a carbon nanotube layer (glass/epoxy dispersed with multiwalled carbon nanotubes), a spacer layer (glass/epoxy) and a perfect electrical conductor layer. A lightning test was performed using an impulse current generator according to standard regulations. Then, nondestructive damage and electromagnetic performance evaluations were performed using a pulse-echo laser ultrasonic propagation imager and a scanning free-space measurement system, respectively. The results showed that neither structural damage nor changes in the electromagnetic properties were observed during the two evaluations. In general, the composites were severely damaged by lightning. However, it turned out that the radar absorbing structure with the carbon nanotube layer could prevent serious damage to stealth function as well as material damage owing to the high conductivity of the carbon nanotubes dispersed in its surface layer.

15

Nadiyyah, Khoirotun, Dwi Wahyu Hardiyanto, Dwi Irma Aprilia, Rizky Firmansyah, Nurul Amaliya Triyuliana e M. Zainuri. "ANALYSIS OF ACTIVATED CARBON (PETUNG BAMBOO)/LATEX COMPOSITE AS X-BAND WAVE-ABSORBING MATERIAL". JOURNAL ONLINE OF PHYSICS 8, n. 2 (1 aprile 2023): 70–76. http://dx.doi.org/10.22437/jop.v8i2.23851.

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In maintaining the sovereignty of a country, especially in border regions was needed defense tools that had the latest technology, such as stealth technology. Stealth technology was applied to military ships or aircraft so that they could not be detected by Radio Detection and Ranging. Stealth technology in this research was realized by coating the ship's or aircraft's body using RAM (Radar Absorbing Material). RAM could be composed of dielectric materials, such as activated carbon. The activated carbon was synthesized from Dendrocalamus Asper. This research aimed to analyze the proper of composition the composite and thickness of the RAM for the X-band wave range. The methods were carbonization, activation by KOH and HCl solutions, and characterization. The characterizations were by XRD, FTIR, and SEM to identify the active carbon phase, and VNA to determine the value of reflection loss. The variations in this research were composite composition (7:3, 9:1) and thickness (1mm, 3mm). And obtained that it has been formed a composite of activated carbon of petung bamboo and latex of rubber tree, which is indicated by the formation of two broad peaks in the diffraction pattern, the presence of band groups C=C, C-C, C-H, C-O, O-H, and morphology with a porous structure. In addition, the highest reflection loss is obtained for the 9:1 composite and thickness of 3 mm, which reached -17.25 dB at a frequency of 9.32 GHz.

16

Zhang, Yuhui, Huaiyu Dong, Chen Yu, Zhichen Wang e Yixing Huang. "Metastructure based broadband structural stealth with material-structure-function integration". Composites Science and Technology 253 (luglio 2024): 110661. http://dx.doi.org/10.1016/j.compscitech.2024.110661.

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Mishra, Monika, Avanish Pratap Singh, Bhanu Pratap Singh e S. K. Dhawan. "Performance of a nanoarchitectured tin oxide@reduced graphene oxide composite as a shield against electromagnetic polluting radiation". RSC Adv. 4, n. 49 (2014): 25904–11. http://dx.doi.org/10.1039/c4ra01860e.

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Wu, Wen Ting, Yi Ren e Heng Yu Zhao. "Research on Application of Plant Structure Bionics in Building Materials". Key Engineering Materials 480-481 (giugno 2011): 904–7. http://dx.doi.org/10.4028/www.scientific.net/kem.480-481.904.

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Since ancient times, nature has been the source of various principles of science and technology and major invention. The features of plant structure bionics, history of application of plant structure bionics in building sector and its applications in high intensity composite material bionics, self-cleaning effect bionics, intelligent information and bionic control, stealth materials and biomimetic materials bionics and other building materials were demonstrated in this paper. Issues for further research were also discussed to provide more inspiration and reference for further innovation.

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Luo, Zhong, e Yue Dong Shi. "The Acoustic Character Analysis of the Sandwich Composite Structure with Cavum in Water Backing". Applied Mechanics and Materials 291-294 (febbraio 2013): 2581–85. http://dx.doi.org/10.4028/www.scientific.net/amm.291-294.2581.

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Sandwich composite is a new structure of acoustic stealth structure, implementing both loading and acoustic stealth. The syntony of cavum can improve the absorption effect in low frequency. This paper uses FEM analysis method, which has been proved theoretically with typical cases and experimental results, to analyze the effect of sandwich material parameter and cavum physical in water backing. The reflection and absorption coefficient in different module, poisson ratio, and density of sandwich, and different depth, location, diameter, interval, and shape of cavum are analyzed. It can support the acoustic design of underwater sandwich composite structure with cavum.

20

Zhang, Wen Cheng, Sui Hua Zhou e An Lin Jiang. "Study on the Application of Viscoelastic Material in Sound Absorption Structure Model". Advanced Materials Research 217-218 (marzo 2011): 341–46. http://dx.doi.org/10.4028/www.scientific.net/amr.217-218.341.

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Study on new absorption materials is important to the sound stealth of targets underwater. The simpler formulae of calculating multiple-layer absorption model is educed with transferring matrix. By numerical simulating, the relation between model’s acoustic characteristics and material parameters of each layer is provided.The study shows that a better performance is acquired when material Young’s modulus changed dynamically with frequency by a certain rule. On these basises, simulation contrast of the absorbing performances between styrene-butadiene rubber(SBR) and Spray Poiyurea Elastomer(SPUA) was carried out. The simulating result and the experiment provided that SPUA has good performance.

21

Dash, Akshay K., Priyanka P. Singh e Ganeswar Nath. "Estimation of reflection loss in a microwave absorbing material based on the laser speckle method". Laser Physics Letters 20, n. 8 (10 luglio 2023): 086004. http://dx.doi.org/10.1088/1612-202x/ace2b3.

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Abstract Microwave absorption has received much attention due to its prospective implementation in the extenuation of electromagnetic interference (EMI). The effectiveness of any microwave absorbing material (MAM) is demonstrated by its dielectric dependent properties, such as electric permittivity, magnetic permeability and computed parameters like tangent loss, attenuation and reflection loss (RL) etc. RL is one of the special features of MAMs, allowing the quality of a MAM to be identified by its surface condition and the composition of the fabricated material. As a surface phenomenon, RL depends on factors such as the surface roughness, thickness of the layering of the material and the nature of the surface. The present work emphasizes the effect of surface roughness on RL, studied using the laser speckle technique (LST). Three different compositions of 10 wt%, 30 wt% and 50 wt% of two carbon-based natural fiber composites are studied for microwave absorption. The surface roughness of the material is analyzed, based on the scattering signal of laser speckles recorded in a digital storage oscilloscope. Further, the roughness of the same composition was recorded through a stylus-based profilometer and compared with the measurements from the LST. The results indicate the effectiveness of the laser contrast technique for determining the surface roughness in the design of stealth materials for EMI shielding applications. The RLs of the designed material are found to be greatly enhanced, having a larger surface roughness value with increasing wt%. The RL of the material with 50 wt% composition has been found to be −23.62 dB at 10.498 GHz. This result clearly indicates the applicability of the LST for the estimation of surface conditions to assess the suitability of MAMs in the design of stealth materials.

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Zhang, Han, Zekui Zhang e Baoyi Li. "Design of Stealth Bulletproof Material Based on Sub-Wavelength Absorbing Structure". IOP Conference Series: Materials Science and Engineering 774 (27 marzo 2020): 012097. http://dx.doi.org/10.1088/1757-899x/774/1/012097.

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Tamadate, Yuka, Hideki Maruyama, Katsunori Aoki, Takashi Ozawa e Haruo Sorimachi. "Novel Backside Grinding and Laser Dicing Process for Cu Pillar Generated Low-k Wafer". International Symposium on Microelectronics 2013, n. 1 (1 gennaio 2013): 1–4. http://dx.doi.org/10.4071/isom-2013-wp54_shinko_late.

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One of the challenges in using very thin die, which is needed in thin package, is how to dice it cleanly without chipping, delamination of fragile low-k insulation material and contamination of bonding pads. A narrow scribe line is also highly preferable for high wafer area utilization. The authors developed a novel "grooving and stealth laser process" to satisfy all of these criteria. Grooves are formed on test pads in die sawing area by a grooving laser beam, and then a stealth laser beam is focused into the bulk silicon, causing defect regions in the bulk silicon. Dicing tape is expanded so that the wafer breaks into separated dice.

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Liu, Yang, Jianbang Zhou, Qi Chang, Ji Liu, Jinzu Ji e Li-Hua Shao. "Transparent and electrically tunable electromagnetic wave absorbing metamaterial". Applied Physics Letters 120, n. 9 (28 febbraio 2022): 094101. http://dx.doi.org/10.1063/5.0083047.

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Electromagnetic protection materials are widely used in both military and civilian fields. However, the limited wave-absorbing band and low transparency of conventional electromagnetic protection materials are the impediment for extensive applications. Here, a transparent and electrically tunable wave-absorbing metamaterial for stealth technology and electromagnetic protection has been theoretically and experimentally realized. The trend of the absorption feature change in simulation is consistent with that of the experiment results. The main part of this material adopts a sandwich structure consisting of two layers of indium tin oxide (ITO) and one layer of glass in between. The upper ITO layer is periodically patterned and combined with varactor diodes, which function as a frequency-selective surface. The effective operating frequency range is in the S-band, which covers the common frequency band of WiFi and many other electronic devices. The wave absorbing performance of this material can be electronically tunable by changing the applied voltage. The main absorption peak can be up to 90% with a tunable amplitude range of 30% and a tunable frequency band range of 1 GHz, and the transmittance of the sample in the visible is 80.23%. The metamaterial has high performance on electromagnetic shielding, whose effectiveness is larger than 30 dB in the range of 2.6–3.95 GHz. This transparent and tunable metamaterial has great potential for the applications in electromagnetic protection and stealth.

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Chéron, Élie, Simon Félix, Jean-Philippe Groby, Vincent Pagneux e Vicente Romero-García. "Wave transport in stealth hyperuniform materials: The diffusive regime and beyond". Applied Physics Letters 121, n. 6 (8 agosto 2022): 061702. http://dx.doi.org/10.1063/5.0097894.

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By varying the degree of correlation in stealthy hyperuniform (SHU) materials, the continuous evolution from uncorrelated disorder to periodic media is possible and allows us, as such, to study the fate of the bimodal distribution, the characteristic of a diffusive transport. Considering the wave transport through a SHU distribution of a given number of scatterers and at a given frequency, the transition from a diffusive to a transparent medium is clearly observed only below the Bragg frequency. This transition is characterized by a threshold value of the stealthiness at the vicinity of which the material abruptly changes from diffusive to transparent. In contrast, no such clear transition is observed at or above the Bragg frequency and, surprisingly, a seemingly bimodal distribution of the transmission eigenvalues still characterizes the SHU materials, even when strongly correlated.

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Jing, Tammy. "Selective Reflection of Cholesteric Liquid Crystals". Science Insights 40, n. 5 (30 aprile 2022): 515–17. http://dx.doi.org/10.15354/si.22.re051.

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Cholesteric liquid crystal materials with selective reflection characteristics are used in a variety of applications due to their unique optical properties, including liquid crystal photovoltaic panels, light enhancement films, liquid crystal dimming glass, liquid crystal dimming films, laser protection, and infrared stealth. At the moment, researchers have offered a variety of effective strategies for extending the range of reflection. The reflection wavelength of the cholesteric phase has been effectively widened through the investigation of each material system, laying the groundwork for the practical application of cholesteric phase liquid crystal materials.

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Anuradha, Sathyamurthy, e Jyothi Balakrishnan. "RESONANCE BASED DISCRIMINATION OF STEALTH TARGETS COATED WITH RADAR ABSORBING MATERIAL (RAM)". Progress In Electromagnetics Research M 99 (2021): 69–79. http://dx.doi.org/10.2528/pierm20101001.

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Gaudiuso, Caterina, Annalisa Volpe e Antonio Ancona. "One-Step Femtosecond Laser Stealth Dicing of Quartz". Micromachines 11, n. 3 (22 marzo 2020): 327. http://dx.doi.org/10.3390/mi11030327.

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We report on a one-step method for cutting 250-µm-thick quartz plates using highly focused ultrashort laser pulses with a duration of 200 fs and a wavelength of 1030 nm. We show that the repetition rate, the scan speed, the pulse overlap and the pulse energy directly influence the cutting process and quality. Therefore, a suitable choice of these parameters was necessary to get single-pass stealth dicing with neat and flat cut edges. The mechanism behind the stealth dicing process was ascribed to tensile stresses generated by the relaxation of the compressive stresses originated in the laser beam focal volume during irradiation in the bulk material. Such stresses produced micro-fractures whose controlled propagation along the laser beam path led to cutting of the samples.

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Chen, Zhuo, Shengli Zhu, Chenghui Feng e Changtao Liu. "Multi-objective optimization design and analysis of large deformation composite material". Journal of Physics: Conference Series 2383, n. 1 (1 dicembre 2022): 012110. http://dx.doi.org/10.1088/1742-6596/2383/1/012110.

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In the future, advanced aircraft proposes to reduce the gaps on the surface of the body to improve the flight performance and stealth performance of the aircraft. This requires a sealing device between the movable surface of the leading and trailing edges of the wing and the fixed wing surface. Based on the sealing of the wing gap, this paper uses CATIA software combined with HyperWorks and ABAQUS software to design and optimize a large-deformation composite structure that can follow the large-scale movement of the movable surface without affecting the movement of the movable surface of the wing.

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An, Yi, Han Zou e Aiguo Zhao. "Broadband Waterborne Multiphase Pentamode Metastructure with Simultaneous Wavefront Manipulation and Energy Absorption Capabilities". Materials 16, n. 14 (17 luglio 2023): 5051. http://dx.doi.org/10.3390/ma16145051.

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Acoustic metastructures are artificial structures which can manipulate the wavefront in sub-wavelength dimensions, and previously proposed acoustic metastructures have been mostly realized with single materials. An acoustic metastructure with composite structure is proposed for underwater acoustic stealth considering both wavefront manipulation and sound absorption. The unit cells of the metastructure are composed of a metallic supporting lattice, interconnecting polymer materials and mass balancing columns. With the gradual modulations of equivalent physical properties along the horizontal direction of metastructure, the incident acoustic wave is reflected to other directions. Meanwhile, the polymer material inside the unit cells will dissipate the acoustic wave energy due to inherent damping properties. With the simultaneous modulations of reflected wave direction and scattering acoustic amplitude, significant improvement of the underwater stealth effect is achieved. Compared with single-phase metastructure, the Far-Field Sound Pressure Level (FFSPL) of multiphase metastructure decreases by 4.82 dB within the frequency range of 3 kHz~30 kHz. The linearized mean stress for multiphase metastructure is only 1/3 of that of single-phase metastructure due to it having much thicker struts and much more uniform stress distribution under the same hydrostatic pressure. The proposed composite structure possesses potential applications due to its acceptable thickness (80 mm) and low equivalent density (1100 kg/m3).

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Deng, Jing Lan, e Bing Feng. "Carbonyl Iron/Graphite Double-Layer Structural Absorbing Composite". Advanced Materials Research 557-559 (luglio 2012): 390–93. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.390.

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A study of a new structured composite absorbing material, prepared using carbonyl iron and graphite as absorbers within a resin matrix. The study investigated the effects of varying the concentration of absorbing agent within the layers of the absorbing composite. Results show that the best absorbency was achieved when the impedance-matching layer contained 20% carbonyl iron content and the absorbing layer contained 35% graphite. The peak absorption was -20.19 dB, with a bandwidth of 7.3GHz (R< -10 dB) in the frequency range of 8 to 18 GHz. This work will certainly have significance guiding research on the application of stealth materials and composite materials.

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El Mohtadi, Farah, Richard d’Arcy, Xiaoye Yang, Zulfiye Yesim Turhan, Aws Alshamsan e Nicola Tirelli. "Main Chain Polysulfoxides as Active ‘Stealth’ Polymers with Additional Antioxidant and Anti-Inflammatory Behaviour". International Journal of Molecular Sciences 20, n. 18 (17 settembre 2019): 4583. http://dx.doi.org/10.3390/ijms20184583.

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We present the evaluation of a sulfoxide-based polymer (poly(propylene sulfoxide), PPSO) as a potential ‘stealth’ macromolecule, and at the same time as a pharmacologically active (anti-inflammatory/anti-oxidant) material. The combination of these two concepts may at first seem peculiar since the gold standard polymer in biomaterials and drug delivery, poly(ethylene glycol) (PEG), is ‘stealth’ due to its chemical and biological inertness, which makes it hardly biologically active. Polysulfoxides, on the contrary, may couple a substantial inertness towards biomolecules under homeostatic conditions, with the possibility to scavenge reactive oxygen species (ROS) associated to inflammation. Polysulfoxides, therefore, are rather uniquely, ‘active’ ‘stealth’ polymers. Here, we describe the synthesis of PPSO through controlled oxidation of poly(propylene sulfide) (PPS), which on its turn was obtained via anionic ring-opening polymerization. In vitro, PPSO was characterized by a low toxicity (IC50 ~7 mg/mL at 24 h on human dermal fibroblasts) and a level of complement activation (in human plasma) and macrophage uptake slightly lower than PEG of a similar size. Importantly, and differently from PEG, on LPS-activated macrophages, PPSO showed a strong and dose-dependent ROS (hydrogen peroxide and hypochlorite)-scavenging activity, which resulted in a corresponding reduction of cytokine production.

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Wang, Hai Long, Shan Kui Liu, Yao Yao Qin e Yun Gang Chen. "Hydroxycamptothecin Stealth Liposomes: Containing TPGS as a Novel PEGylated Long-Circulating Coating Material". Advanced Materials Research 886 (gennaio 2014): 333–36. http://dx.doi.org/10.4028/www.scientific.net/amr.886.333.

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The goal of this study was to develop long-circulating liposomes of hydroxylcamptothecin (HCPT) with TPGS as a new coating material. Liposomes were prepared by a thin-film dispersion method with the lipids comprised phosphatidylcholine, cholesterol and TPGS. By contrast, other common PEGylated derivatives were also involved. HCPT-loaded liposomes with TPGS as coating material showed similar physicochemical characteristics andin vitrorelease profile to liposomes with DSPE-PEG or DPPE-PEG. It is suggested that TPGS can be applied as a novel coating material for long-circulating liposomes.

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Bharti Kumari, Abhinav Kumar, Prashant Kumar e Mintu Singh. "Polarization Independent Ultra-wideband Meta-material Absorber Using Conductive Ink Resonator". Journal of Telecommunications and Information Technology, n. 1 (12 febbraio 2024): 39–45. http://dx.doi.org/10.26636/jtit.2024.1.1392.

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A wideband meta-material absorber with square and circular split rings that is based on a frequency selective surface of conductive ink is proposed. With over 90% absorptivity, the structure demonstrates broad absorption for the C, X, KU and K bands, as well as polarization independent characteristics for both TE and TM, at angles of up to 45°. Research has been performed to better understand the absorption phenomenon by looking into real and imaginary permittivity, permeability, normalized impedance, and surface current density. The meta-material absorber (MA) discussed in this study finds use in defense-related applications, such as radar surveillance, stealth technology, terrestrial and satellite communications.

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Sui, Xue Ye, Jie Xu, Mei Ling Wei, Chong Hai Wang, Chang Ling Zhou e Rui Xiang Liu. "Laser Stealth Properties for SiO₂ Hollow Spheres with a Layer of Copper". Advanced Materials Research 624 (dicembre 2012): 38–41. http://dx.doi.org/10.4028/www.scientific.net/amr.624.38.

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A kind of SiO2 hollow spheres with a layer of copper cladding have been prepared using the electroless copper plating metal processing technology on the surface of core material. We Study the effects of the process parameters on the properties of materials, and measure spectral reflectance for the SiO2 hollow spheres with the surface modification. The results show that the reflectance is about 4% for the wavelength of 1.06μm and is about 0.44% for 10.6μm wavelength. This compound hollow sphere structures can be act as laser camouflage materials.

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Luo, Mingyu, Xin Li, Zhaojian Zhang, Hansi Ma, Te Du, Xinpeng Jiang, Zhenrong Zhang e Junbo Yang. "Tunable Infrared Detection, Radiative Cooling and Infrared-Laser Compatible Camouflage Based on a Multifunctional Nanostructure with Phase-Change Material". Nanomaterials 12, n. 13 (30 giugno 2022): 2261. http://dx.doi.org/10.3390/nano12132261.

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The nanostructure composed of nanomaterials and subwavelength units offers flexible design freedom and outstanding advantages over conventional devices. In this paper, a multifunctional nanostructure with phase-change material (PCM) is proposed to achieve tunable infrared detection, radiation cooling and infrared (IR)-laser compatible camouflage. The structure is very simple and is modified from the classic metal–dielectric–metal (MIM) multilayer film structure. We innovatively composed the top layer of metals with slits, and introduced a non-volatile PCM Ge2Sb2Te5 (GST) for selective absorption/radiation regulation. According to the simulation results, wide-angle and polarization-insensitive dual-band infrared detection is realized in the four-layer structure. The transformation from infrared detection to infrared stealth is realized in the five-layer structure, and laser stealth is realized in the atmospheric window by electromagnetic absorption. Moreover, better radiation cooling is realized in the non-atmospheric window. The proposed device can achieve more than a 50% laser absorption rate at 10.6 μm while ensuring an average infrared emissivity below 20%. Compared with previous works, our proposed multifunctional nanostructures can realize multiple applications with a compact structure only by changing the temperature. Such ultra-thin, integratable and multifunctional nanostructures have great application prospects extending to various fields such as electromagnetic shielding, optical communication and sensing.

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Yang, Shuang, Feng Ding, Zhiliang Gao, Jianman Guo, Jiwei Cui e Peiyu Zhang. "Fabrication of Poly(ethylene glycol) Capsules via Emulsion Templating Method for Targeted Drug Delivery". Polymers 12, n. 5 (14 maggio 2020): 1124. http://dx.doi.org/10.3390/polym12051124.

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To reduce nonspecific interactions and circumvent biological barriers, low-fouling material of poly(ethylene glycol) (PEG) is most used for the modification of drug nanocarriers. Herein, we report the fabrication of PEG capsules via the free-radical polymerization of linear PEG or 8-arm-PEG using an emulsion templating method for targeted drug delivery. Doxorubicin (DOX) could be loaded in capsules via electrostatic interactions. The obtained capsules composed of 8-arm-PEG result in a lower cell association (2.2%) compared to those composed of linear PEG (7.3%) and, therefore, demonstrate the stealth property. The functionalization of cyclic peptides containing Arg-Gly-Asp (cRGD) on PEG capsules induce high cell targeting to U87 MG cells. A cell cytotoxicity assay demonstrates the biocompatibility of PEG capsules and high drug delivery efficacy of the targeted capsules. The reported capsules with the stealth and targeting property provide a potential platform for improved drug delivery.

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Jain, Raj, Ashish Dubey, Amit Soni, Sanjiv Gupta e Trilok Shami. "Barium titanate flakes based composites for microwave absorbing applications". Processing and Application of Ceramics 7, n. 4 (2013): 189–93. http://dx.doi.org/10.2298/pac1304189j.

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Barium titanate (BT) has attained research focus in recent past owing to considering its high dielectric constant and stealth capabilities in microwave region. Shape effects of BT viz. powder, micron size flakes, nano particles and nanotubes have been studied vastly for its stealth capabilities. Present study aims at the preparation of millimetric size barium titanate flakes (BTFs) via controlled sol-gel process followed by tape casting. BTFs were mixed in varied weight ratio (50-90 wt.%) with polyurethane resin to fabricate composite laminates. Electromagnetic properties measurement in X and Ku band revealed high values of real and imaginary permittivity. Reflection loss measurements demonstrated more than 20 dB loss in wide frequency range (11.4-13.6 GHz). For single layer microwave absorber, reflection loss values have been calculated and it is observed that calculated and measured reflection loss values are in good agreement to each other. Developed material can find applications in broadband radar signature reduction.

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Pham, Martin H., Luis Daniel Diaz-Aguilar, Bradley H. King, Joseph A. Osorio e Ronald A. Lehman. "Quad S2-Alar-Iliac Screw Fixation via Navigated Spinal Robotics With Software Planning: 2-Dimensional Operative Video". Operative Neurosurgery 19, n. 5 (5 giugno 2020): E523. http://dx.doi.org/10.1093/ons/opaa155.

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Abstract The use of robotic guidance for spinal instrumentation has become promising for its ability to offer the advantages of precision, accuracy, and reproducibility. However, utilization and adoption of robotic platforms for spine surgery remain limited especially in comparison to other surgical fields. We present here a case of a 71-yr-old man with a prior T4-pelvis long-segment fusion who presented with distal sacro-iliac instrumentation loosening with pseudarthrosis. He subsequently underwent construct revision with quad (bilateral dual) S2-alar-iliac screw fixation with navigated spinal robotic assistance (Mazor X Stealth Edition, Medtronic Sofamor Danek, Medtronic Inc, Dublin, Ireland). To our knowledge, this is the first video demonstrating the preoperative software planning and intraoperative workflow for placing quad S2-alar-iliac screws with navigated spinal robotic guidance using the Mazor X Stealth Edition. There is no identifying information in this video. Patient consent was obtained for the surgical procedure and for publishing of the material included in the video.

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Singh, Jaydeep, e Dharmendra Singh. "An Analytical Approach to Design Camouflage Net for Microwave Absorption". Defence Science Journal 69, n. 5 (17 settembre 2019): 469–73. http://dx.doi.org/10.14429/dsj.69.14953.

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Microwave absorption has been the key for reduction of radar cross section in the field of stealth technology. In this field, hiding troop details from reconnaissance systems is taken care by enhancing absorption properties of the material. The demand of masking detectable equipment can be met with the help of a flexible net type structure called camouflage net. Optimising and measuring the absorption of the net, comprising of cloth and coating of the radar absorbing materials over the cloth is very challenging task. The task is being accomplished by using trial and error method, which is very cumbersome process and leads to tremendous waste of potential, material and manpower. Therefore, an attempt to develop an analytical methodology using the permittivity and permeability of the fabric material, to minimise this limitation, has been presented in this paper by critically analysing simulated results for various composites. The approach seems to have good potential for developing the camouflage net, especially in the microwave regime.

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Wei, Biao, Xiaolong Weng, Le Yuan, Lun Qi, Gang Huang, Xingbo Du e Mei Bi. "Numerical simulation and analysis of wall temperature based on the tangent oval model under different speed and radiation conditions". Journal of Physics: Conference Series 2355, n. 1 (1 ottobre 2022): 012050. http://dx.doi.org/10.1088/1742-6596/2355/1/012050.

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Abstract In this paper, the influence mechanism of flight speed, altitude and emissivity of skin material on the temperature of aircraft wall were systematically analysed by numerical simulation. The results show that the increase of the velocity would lead to the rise of the wall pressure and temperature of the aircraft. In addition, a speed of 5 Ma and flight altitude at 30 km, the heat transmitted to the outside was reduced with the decrease of skin material emission. As a result, the constant increase of its own heat energy, which led to the continuous rise of the wall temperature of the aircraft. And the total target radiation emission was reduced by 58.8% with the decrease of emissivity (from 0.8 to 0.2). These results show that the infrared radiation of the aircraft could effectively be suppressed by low emissivity material, the infrared stealth performance of aircraft was enhanced. The research has guiding significance for the temperature-resistant characteristics of skin materials and infrared radiation control.

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Hu, Shao-Hwa, Jiao-Jiao Yuan, Hang Dai, Yang-Yang Liu, Jing He e Jun-Ling Tu. "Preparation of a Flexible X-Band Radar-Wave-Absorbing Composite Material by Using Beta-Silicon Carbide and Polyurethane as Substrates and Multiwalled Carbon Nanotubes as Additives". Symmetry 14, n. 10 (14 ottobre 2022): 2144. http://dx.doi.org/10.3390/sym14102144.

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Silicon carbide (SiC) has good chemical resistance, excellent mechanical properties, thermal conductivity, especially in extreme conditions of application, and has proved to be a very promising electromagnetic absorption material. However, single silicon carbide cannot meet the increasing demand for high performance of absorbing materials. It has become an important research direction to combine it with other absorbing materials to improve its absorbing performance. In this study, a composite absorber material was prepared by 50 wt.% micron-sized beta-silicon carbide (β-sic) powder, mixed with a 0.2 wt.% multiwalled carbon nanotubes (MWCNTs) and 50 wt.% polyurethane (PU) substrate. The mixture was stirred and deaerated to form a slurry, and sprayed onto synthetic fabric. The results showed that the composite material was flexible, with a thickness of less than 2 mm and favorable adhesion. The results obtained by reflection graph of the radar waves, indicated that the return loss within the X-band range (8–12 GHz) was less than −40 dB, indicating favorable radar wave absorption. Therefore, composite materials could thus be used successfully as radar wave absorbers, and was suitable for stealth materials in “asymmetric warfare”.

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Chaturvedi, Richa, Yumin Kang, Yunji Eom, Sri Ramulu Torati e CheolGi Kim. "Functionalization of Biotinylated Polyethylene Glycol on Live Magnetotactic Bacteria Carriers for Improved Stealth Properties". Biology 10, n. 10 (1 ottobre 2021): 993. http://dx.doi.org/10.3390/biology10100993.

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The early removal of drug delivery agents before reaching the affected target remains an area of interest to researchers. Several magnetotactic bacteria (MTB) have been used as self-propelled drug delivery agents, and they can also be controlled by an external magnetic field. By attaching the PEG–biotin polymer, the bacteria are turned into a stealth material that can escape from the phagocytosis process and reach the area of interest with the drug load. In the study, we developed a potential drug carrier by attaching the PEG–biotin to the MTB-through-NHS crosslinker to form a MTB/PEG–biotin complex. The attachment stability, efficacy, and bacterial viability upon attachment of the PEG–biotin polymer were investigated. Biological applications were carried out using a cytotoxicity assay of THP-1 cells, and the results indicate that the MTB/PEG–biotin complex is less harmful to cell viability compared to MTB alone. Along with cytotoxicity, an assay for cell association was also evaluated to assess the complex as a potential stealth material. The development of these complexes focuses on an easy, time-saving, and stable technique of polymer attachment with the bacteria, without damaging the cell’s surface, so as to make it a strong and reliable delivery agent.

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Joy, Vineetha, Vishal Padwal, Raveendranath U. Nair e Hema Singh. "Optimal Design of Multilayered Radar Absorbing Structures (RAS) using Swarm Intelligence based Algorithm". Defence Science Journal 72, n. 2 (11 maggio 2022): 236–42. http://dx.doi.org/10.14429/dsj.72.17417.

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The steady progress in the fields of material science and processing technologies has made multi-layered radar absorbing structures (RAS) an attractive option w.r.t. stealth technologies. They possess the ability to reduce radar cross-section with minimum thickness and is therefore most preferred in airborne applications. As far as their electromagnetic performance is concerned, the sequence of material layers and thickness profile plays a pivotal role. Optimization of these two factors becomes complex in case of availability of large number of potential materials. Commonly used EM simulation software can be employed for the optimization of thickness profile. However, selection of suitable material layer sequence is out of their scope. In this context, a particle swarm optimization (PSO) based algorithm is presented for sequencing of material layers and optimization of thickness profile of multi-layered RAS configurations. The fitness function has been appropriately formulated to achieve maximum power absorption over broad band of frequencies and wide range of incident angles. Further, the efficacy of the algorithm has been demonstrated using a suitable case study.

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Han, Hye Ree. "Hybrid Fiber Materials According to the Manufacturing Technology Methods and IOT Materials: A Systematic Review". Materials 16, n. 4 (5 febbraio 2023): 1351. http://dx.doi.org/10.3390/ma16041351.

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With the development of convergence technology, the Internet of Things (IoT), and artificial intelligence (AI), there has been increasing interest in the materials industry. In recent years, numerous studies have attempted to identify and explore multi-functional cutting-edge hybrid materials. In this paper, the international literature on the materials used in hybrid fibers and manufacturing technologies were investigated and their future utilization in the industry is predicted. Furthermore, a systematic review is also conducted. This includes sputtering, electrospun nanofibers, 3D (three-dimensional) printing, shape memory, and conductive materials. Sputtering technology is an eco-friendly, intelligent material that does not use water and can be applied as an advantageous military stealth material and electromagnetic blocking material, etc. Electrospinning can be applied to breathable fabrics, toxic chemical resistance, fibrous drug delivery systems, and nanoliposomes, etc. 3D printing can be used in various fields, such as core-sheath fibers and artificial organs, etc. Conductive materials include metal nanowires, polypyrrole, polyaniline, and CNT (Carbon Nano Tube), and can be used in actuators and light-emitting devices. When shape-memory materials deform into a temporary shape, they can return to their original shape in response to external stimuli. This study attempted to examine in-depth hybrid fiber materials and manufacturing technologies.

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Huang, Xinxin, Xiaodong Pan, Fang Zhao, Jinning Liu e Zhaogang Cheng. "Laser-Infrared compatible stealth coating material with good mechanical properties and self-healing capability". Materials Letters 364 (giugno 2024): 136339. http://dx.doi.org/10.1016/j.matlet.2024.136339.

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Gal-Or, Benjamin. "Expanded R&D by Jet-engine-steering Revolution". International Journal of Turbo & Jet-Engines 34, n. 4 (26 ottobre 2017): 305–11. http://dx.doi.org/10.1515/tjj-2017-5001.

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Abstract Since 1987 [1, 2, 3, 4, 5] the global jet engine community is facing the historical fact that jet engine steering is gradually replacing canards and the common, often dangerous and obsolete, aerodynamic-only flight control – a fact that (i) has already affected the defense-industrial complex in the US, Russia, China, Japan, S-Korea and India, (ii) has integrated the traditional jet-engine components R&D with advanced aero-electro-physics, stealth technology, thrust vectoring aerodynamics and material science. Moreover, this military revolution is historically due to expand into the civil transport jets domain, [6, 7, 8, 9]. The historical aim of the JES-Revolution remains the same: Replace the common, stall-spin sensitive canards [6] and Aerodynamic-Only-Obsolete-Flight Control (“AOOF Control”). Invented about 100 years ago for propeller-driven air vehicles, it has already been partially replaced for failure to function in WVR-combat post-stall domain, and for the following reasons: In comparison with complete Tail-Less, Canard-Less, Stealth-JES (Figure 5 and References [1, 2, 3, 4, 5, 6]), the common AOOF Control increases drag, weight, fuel consumption, complexity, cost, and reduces flight safety, stealth, [Low Detectability] and provides zero post-stall, WVR air combat capability while its CANARDS KILL LD & REDUCE JES. Examples of stealth fighter aircraft that have already replaced canards and AOOF-Control where JES provides at least 64 to 0 KILL-RATIO advantage over AOOF-Controlled conventional fighter aircraft: The U.S. JES F-22 and, apparently, the Russian JES-Su-T-50 & 35S, China 2016-J-31, Indian HAL AMCA & FGFA, Japanese JES IHHI ATD-X, S-Korean JES KF-X. Cf. X-44 in Figure 5. Consequently, the jet engine is no longer defined as providing only brute force forward. Instead, it successfully competes with and wins over the wrong, dominating AOOF-Control, at least as a backup flight control whose sole factual domain is currently a well-established, primary flight controller RE any post-stall, super-agility, [2, 3, 4, 5, 6, 7, 8, 9].

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Zhang, Xiao Hu, Qin Sun e Shao Feng Xu. "Optimal Design of Multi-Layer Absorbent Honeycomb Cellular Composite Material Structure". Key Engineering Materials 723 (dicembre 2016): 335–43. http://dx.doi.org/10.4028/www.scientific.net/kem.723.335.

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Next generation aircraft rely heavily on lightweight honeycomb composite structures for improved electromagnetic wave scattering and stealth capabilities. This paper investigated the optimal design and analysis methods of multi-layer absorbent honeycomb composite structures. The effective electromagnetic parameters of anisotropic object were calculated accompany with the formulation of reflectivity for incident wave. A genetic algorithm is employed to optimize the RCS of the absorptive honeycomb composite in desired angle range. The thickness and the volume fraction of absorptive materials are adopted to optimize the effective electromagnetic parameters under different polarized modes. Single and multi layer absorptive honeycomb composite were been studied. The results show that the thickness of the first absorptive layer plays a key role on the reflectivity of honeycomb structure. Therefore, it is advised to arrange the absorptive layers such that the EM absorption properties increases from outside to inside.

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Lokhande, Vinay S. "Study on Infrared (IR) Camouflage Using Mylar in the Defense Sector". International Journal for Research in Applied Science and Engineering Technology 12, n. 5 (31 maggio 2024): 2600–2612. http://dx.doi.org/10.22214/ijraset.2024.62146.

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Abstract: This project investigates the feasibility of utilizing Mylar, a highly reflective polyester film, for infrared (IR) camouflage in the defense sector. Through a comprehensive analysis of Mylar's optical properties, including its reflectivity and reflectance, this study aims to assess the material's potential for reducing thermal signatures and enhancing stealth capabilities of military assets. The research involves theoretical and numerical analysis to evaluate Mylar's performance under various environmental conditions, such as temperature extremes, humidity, and exposure to ultraviolet (UV) radiation. Furthermore, the project explores the integration of Mylar-based IR camouflage into existing defense systems, including vehicle coatings, personnel gear, and tactical equipment. Recommendations for the deployment and optimization of Mylar-based camouflage solutions are provided, addressing factors such as material selection, camouflage design, compatibility with sensor systems, and logistical support. The findings demonstrate Mylar's efficacy in decreasing IR detectability, providing a cost-effective and versatile solution in IR camouflage. This research contributes significantly to the field of defense technology, offering practical insights and paving the way for further advancements in stealth and counter-detection measures in military applications.

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Yang, Bo, Heng Wang, Sheng Peng e Qiang Cao. "Precision Layered Stealth Dicing of SiC Wafers by Ultrafast Lasers". Micromachines 13, n. 7 (27 giugno 2022): 1011. http://dx.doi.org/10.3390/mi13071011.

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With the intrinsic material advantages, silicon carbide (SiC) power devices can operate at high voltage, high switching frequency, and high temperature. However, for SiC wafers with high hardness (Mohs hardness of 9.5), the diamond blade dicing suffers from problems such as debris contaminants and unnecessary thermal damage. In this work, a precision layered stealth dicing (PLSD) method by ultrafast lasers is proposed to separate the semi-insulated 4H-SiC wafer with a thickness of 508 μm. The laser power attenuates linearly from 100% to 62% in a gradient of 2% layer by layer from the bottom to the top of the wafer. A cross section with a roughness of about 1 μm was successfully achieved. We have analyzed the effects of laser pulse energy, pulse width, and crystal orientation of the SiC wafer. The anisotropy of the SiC wafer results in various qualities of PLSD cross sections, with the roughness of the crystal plane {10−10} being 20% lower than that of the crystal plane {11−20}.

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