期刊文献+
共找到4,329篇文章
< 1 2 217 >
每页显示 20 50 100
Efficacy and safety of solifenacin plus tamsulosin oral controlled absorption system in men with lower urinary tract symptoms: a meta-analysis 被引量:1
1
作者 Ming-Chao Li Zheng-Yun Wang +5 位作者 Jun Yang Xiao-Lin Guo Tao Wang Shao-Gang Wang Ji-Hong Liu Zhang-Qun Ye 《Asian Journal of Andrology》 SCIE CAS CSCD 2015年第1期124-134,I0011,共12页
We performed a meta-analysis to compare treatment with a combination of solifenacin plus tamsulosin oral controlled absorption system (TOCAS) with placebo or TOCAS monotherapy. The aim of the meta-analysis was to cl... We performed a meta-analysis to compare treatment with a combination of solifenacin plus tamsulosin oral controlled absorption system (TOCAS) with placebo or TOCAS monotherapy. The aim of the meta-analysis was to clarify the efficacy and safety of the combination treatments method for lower urinary tract symptoms (LUTS). We searched for trials of men with LUTS that were randomized to combination treatment compared with TOCAS monotherapy or placebo. We pooled data from three placebo-controlled trials meeting inclusion criteria. Primary outcomes of interest included changes in International Prostate Symptom Score (IPSS) and urinary frequency. We also assessed postvoid residual, maximum urinary flow rate, incidence of urinary retention (UR), adverse events. Data were pooled using random or fixed effect models for continuous outcomes and the ManteI-Haenszel method to generate risk ratio. Reductions in IPSS storage subscore and total urgency and frequency score (TUFS) were observed with solifenacin 6 mg plus TOCAS compared with placebo (P 〈 0.0001 and P 〈 0.0001, respectively). Reductions in IPSS storage subscore and TUFS were observed with solifenacin 9 mg plus TOCAS compared with placebo (P= 0.003 and P = 0.0006, respectively). Reductions in TUFS was observed with solifenacin 6 mg plus TOCAS compared with TOCAS (P = 0.01). Both combination treatments were well tolerated, with low incidence of UR. Solifenacin 6 mg plus TOCAS significantly improved total IPSS, storage and voiding symptoms compared with placebo. Solifenacin 6 mg plus TOCAS also improved storage symptoms compared with TOCAS alone. There was no additional benefit of solifenacin 9 mg compared with 6 mg when used in combination with TOCAS. 展开更多
关键词 combination therapy lower urinary tract symptoms SOLIFENACIN tamsulosin oral controlled absorption system
原文传递
Improvement of Tunable Diode Laser Absorption System with a Novel Multipass Cell and Wavelet Transform 被引量:1
2
作者 夏滑 涂郭结 +3 位作者 庞涛 张志荣 吴边 董凤忠 《Journal of Measurement Science and Instrumentation》 CAS 2011年第4期402-405,共4页
Combination of Tunable Diode Laser Absorption Spectroscopy(TDLAS)technique and multipass cell is an attractive approach for ultrahigh sensitive detection of trace gases.Theoretically,based on Beer-Lambert law,the long... Combination of Tunable Diode Laser Absorption Spectroscopy(TDLAS)technique and multipass cell is an attractive approach for ultrahigh sensitive detection of trace gases.Theoretically,based on Beer-Lambert law,the longer optical path length and the larger gas absorption,the lower concentration gas could be detected.However,lower radiation intensity and inevitable etalon fringe resulted from multiple reflections would greatly weaken the Signal-to-Noise Ratio(SNR)and thus an expected ultrahigh sensitive detection system is difficult to achieve.In order to fully make use of the advantages of TDLAS and multipass cell,the base length and the total optical path length of the multipass cell are needed to be carefully balanced.Furthermore,the harmonic signals contaminated by various noises are processed with wavelet transform method.As a demonstration of this method,few low concentrations of gas CO in N2 are measured employing TDLAS technique and a novel sealed multipass cell with total optical length of 114 m.The detection limit is about 5×10-6(volume ratio),which is one order of magnitude better than earlier noise reduction. 展开更多
关键词 absorption spectroscopy TDLAS multipass cell etalon fringe wavelet transform detection limit
在线阅读 下载PDF
Thermodynamic Analysis of Double Effect Absorption System along with Boiler and Cooling Tower
3
作者 Saeed Sedigh Hamid Saffari Hamidreza Taleshbahrami 《Journal of Environmental Science and Engineering(A)》 2012年第2期261-270,共10页
Many researchers have studied single and double effect absorption cycles based on first and second lows of thermodynamics But so far the relation of different parameters inside these cycles to the second law of thermo... Many researchers have studied single and double effect absorption cycles based on first and second lows of thermodynamics But so far the relation of different parameters inside these cycles to the second law of thermodynamics in boiler and cooling tower has not been investigated. In this paper, a system comprised of a series flow double effect water-Lithium bromide absorption chiller, a boiler and a cooling tower is studied based on the first and second laws of thermodynamics, and also exergy analysis is investigated. For this purpose, mass and energy conservation laws governing the system are written, and coefficient of performance of the system, exergy destruction (loss) of each component and exergy efficiency have been calculated. 展开更多
关键词 absorption chiller thermodynamic analysis cooling tower.
在线阅读 下载PDF
The redshift number density evolution of Mg Ⅱ absorption systems
4
作者 Zhi-Fu Chen 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2013年第6期641-650,共10页
We make use of the recent large sample of 17 042 Mg Ⅱ absorption systems from Quider et al. to analyze the evolution of the redshift number density. Regardless of the strength of the absorption line, we find that the... We make use of the recent large sample of 17 042 Mg Ⅱ absorption systems from Quider et al. to analyze the evolution of the redshift number density. Regardless of the strength of the absorption line, we find that the evolution of the redshift number density can be clearly distinguished into three different phases. In the intermediate redshift epoch (0.6 ≤ z ≤ 1.6), the evolution of the redshift number density is consis- tent with the non-evolution curve, however, the non-evolution curve over-predicts the values of the redshift number density in the early (z ≤ 0.6) and late (z ≥ 1.6) epochs. Based on the invariant cross-section of the absorber, the lack of evolution in the red- shift number density compared to the non-evolution curve implies the galaxy number density does not evolve during the middle epoch. The fiat evolution of the redshift number density tends to correspond to a shallow evolution in the galaxy merger rate during the late epoch, and the steep decrease of the redshift number density might be ascribed to the small mass of halos during the early epoch. 展开更多
关键词 methods: statistical -- galaxies: evolution -- quasars: absorption lines
在线阅读 下载PDF
Non-Linear Analysis of Energy Absorption Systems under Impact Loads through FEM
5
作者 Elias Rigoberto Ledesma-Orozco Jose Angel Diosdado-De la Pena Gerardo Israel Pdrez-Soto Alonso Salazar-Garibay Juan Francisco Reveles-Arredondo Gilberto Villalobos-Llamas Pedro Duran-Resendiz 《Journal of Mechanics Engineering and Automation》 2012年第8期487-494,共8页
This paper presents a non-linear simulation of the impact on a structure with different energy absorption systems using finite element models. Literature review on bistable structure, aluminum foam and expandable poly... This paper presents a non-linear simulation of the impact on a structure with different energy absorption systems using finite element models. Literature review on bistable structure, aluminum foam and expandable polystyrene is presented and taken as basis to propose energy absorption systems. Using a base structure, these systems are implemented by means of finite element modeling. A comparison of the damage caused to the structure in case of impact without implementing energy absorption system, and implementing energy absorption systems based on bistable structures, polystyrene foam and aluminum foam are shown here in. The results demonstrate the advantages of using energy absorption systems on structures under impact loads. 展开更多
关键词 BISTABLE impact loads non-linear analysis energy absorption.
在线阅读 下载PDF
Advancements and challenges in chemical absorption technologies for shipborne carbon capture applications:Absorbent development,improvement of absorption towers,and system integration
6
作者 Yidong Zhang Huijin Xu +1 位作者 Jiahui Xu Xuelai Zhang 《Journal of Energy Chemistry》 2025年第7期880-910,共31页
The International Maritime Organization(IMO)aims to reduce shipping greenhouse gas emissions by 70%by 2050,positioning onboard carbon capture(OCC)systems as essential tools,with chemical absorption being particularly ... The International Maritime Organization(IMO)aims to reduce shipping greenhouse gas emissions by 70%by 2050,positioning onboard carbon capture(OCC)systems as essential tools,with chemical absorption being particularly favorable due to its retrofit viability.This review analyzes advancements in chemical absorption technologies specific to shipborne applications,focusing on absorbent development,absorption tower optimization,and system integration.This article begins with an overview of OCC principles and advantages,followed by a discussion of technological progress,including feasibility studies and project outcomes.It explores various chemical absorbents,assessing performance,degradation,and emissions.The structural configurations of absorption towers and their modeling techniques are examined,alongside challenges such as limited vessel space,energy constraints,and gas-liquid distribution inefficiencies.Future directions emphasize the need for innovative absorbent designs,advanced simulation for tower optimization,and enhanced integration with ship energy systems,including renewable energy and waste heat recovery.The potential for intelligent technologies to enable real-time monitoring and automated management of carbon capture systems is highlighted.Finally,further investigations into fundamental interfaces and reaction kinetics are essential for advancing shipborne carbon capture technologies,providing a crucial reference for researchers and practitioners in the field. 展开更多
关键词 Chemical absorption Absorbents Chemical absorption tower Computational Fluid Dynamics(CFD) Machine learning Onboard carbon capture(OCC)
暂未订购
Enhancement of electromagnetically induced absorption and four-wave mixing in a double two-level system
7
作者 Yu-Sen Wang Ying-Jie Du 《Chinese Physics B》 2025年第12期250-258,共9页
We present a theoretical investigation of the electromagnetically induced absorption(EIA)due to transfer of population(TOP)in the double two-level system(TLS).It shows that one TLS is responsible for the sub-natural a... We present a theoretical investigation of the electromagnetically induced absorption(EIA)due to transfer of population(TOP)in the double two-level system(TLS).It shows that one TLS is responsible for the sub-natural absorption part of EIA,and the other TLS is responsible for the natural absorption part of EIA.We propose a scheme in which the sub-natural absorption part of EIA is governed by the effect of coherent hole burning(CHB)and achieves an enhancement of at least two orders of magnitude with the detuned coupling field,while the natural absorption part is dominated by the effect of Mollow absorption(MA)and does not change with the detuned coupling field.Due to the effects of CHB and MA,the magnitude of four-wave mixing(FWM)achieves a significant increase for double TLS.We show in detail the evolution of the magnitude of the FWM signal with coupling detuning and Rabi frequency.It is demonstrated that strong resonances occur in the FWM profile at frequencies symmetrically displaced from the frequency of the coupling field by coupling detuning. 展开更多
关键词 electromagnetically induced absorption coherent hole burning Mollow absorption four-wave mixing
原文传递
Ultracold atomic absorption imaging system in high magnetic fields
8
作者 Yuying Chen Zhengxi Zhang +3 位作者 Hongmian Shui Yun Liang Fansu Wei Xiaoji Zhou 《Chinese Physics B》 2025年第5期370-377,共8页
Absorption imaging is a fundamental technique for quantitatively extracting information from ultracold atom experiments.Since ultracold^(6)Li atoms are prepared and detected under high magnetic fields,the suitable det... Absorption imaging is a fundamental technique for quantitatively extracting information from ultracold atom experiments.Since ultracold^(6)Li atoms are prepared and detected under high magnetic fields,the suitable detuning of the probe light can reach the GHz level compared to zero-field imaging.Therefore,based on the energy level structure of^(6)Li atoms and the requirements of subsequent experiments,we design a high-field imaging system with a large frequency range and good robustness,starting from the rationality of the optical layout design and employing offset locking techniques.This imaging system covers the entire crossover region from Bose–Einstein condensate to Bardeen–Cooper–Schrieffer(BEC–BCS)and realizes free switching between zero-field and high-field imaging.Additionally,by introducing a proportionality coefficient to correct for the intensity fluctuations of the probe light,we mitigate its disturbance on the statistical measurement of particle numbers in the experiment.This work not only provides a design reference for other quantum gas experiments requiring absorption imaging under strong bias magnetic fields,but also serves as an important reference for improving the imaging performance. 展开更多
关键词 absorption imaging high field imaging offset locking light intensity correction
原文传递
Electromagnetically-induced-absorption-like ground state cooling in a hybrid optomechanical system
9
作者 Yaoyong Dong Xuejun Zheng +1 位作者 Denglong Wang Peng Zhao 《Chinese Physics B》 2025年第4期413-421,共9页
We present a scheme for the electromagnetically-induced-absorption(EIA)-like ground state cooling in a hybrid optomechanical system which is combined by two-level quantum systems(qubits)and a high-Q optomechanical cav... We present a scheme for the electromagnetically-induced-absorption(EIA)-like ground state cooling in a hybrid optomechanical system which is combined by two-level quantum systems(qubits)and a high-Q optomechanical cavity.Under the weak qubit-cavity coupling,the system exhibits an EIA-like effect and this effect is caused by quantum destructive interference that is distinct from the conventional EIA effect driven by quantum constructive interference.More importantly,the EIA-like cooling mechanism can significantly enhance the cooling rate of the hybrid system,enabling the final phonon number beyond the classical cooling limit in the strong optomechanical coupling regime.Meanwhile,the cooling effects of the EIA case is better than that of the normalmode splitting case under the same optomechanical coupling strength and qubit dissipation rate. 展开更多
关键词 electromagnetically induced absorption ground state cooling OPTOMECHANICS
原文传递
Chitosan as oral absorption enhancer and inhibitor:A comprehensive review
10
作者 Sajid Hussain Omer M.A.Dagah +8 位作者 Essam A.M.S Obaid Peng Jin Ovas Ahmed Dar Muhammd Irfan Yiming Qi Qinghua Wu Ming Jin Tengli Zhang Lei Luo 《Chinese Chemical Letters》 2026年第1期137-147,共11页
Chitosan(CS),a natural polymer derived from chitin found in the exoskeletons of crustaceans,has garnered significant interest in the pharmaceutical field due to its unique properties,including biocompatibility and bio... Chitosan(CS),a natural polymer derived from chitin found in the exoskeletons of crustaceans,has garnered significant interest in the pharmaceutical field due to its unique properties,including biocompatibility and biodegradability.In recent years,various studies have reported that CS can affect drug bioavailability,and interestingly,it works as an oral absorption enhancer and inhibitor.This review offers an in-depth analysis of the mechanisms underlying such a phenomenon and supports its application as a pharmaceutical excipient.CS enhances oral drug absorption through various mechanisms,such as interaction with the intestinal mucosa,tight junction modulation,inhibition of efflux transporters,enzyme inhibition,solubility and stability enhancement,and complexation.On the other side,CS exhibits the ability to inhibit the absorption of certain drugs by adsorbing to lipids and sterols,modulating bile acids and gut microbiota,altering drug-cell interaction at the polar interface,and mucus-mediated entrapment and interference.Future potential pharmaceutical research in this field includes elucidating the underneath absorption relevant mechanisms,rational use in formulations as excipient,exploring functional CS derivatives,and developing CS-based drug delivery systems.This comprehensive review highlights CS's versatile and significant role in enhancing and inhibiting oral drug absorption,providing insights into the complexities of drug delivery and the potential of CS to improve therapeutic outcomes. 展开更多
关键词 Oral absorption EXCIPIENTS CHITOSAN ENHANCER INHIBITOR
原文传递
Energy absorption characteristics of additively manufactured sea sponge-inspired lattice structures under low-velocity impact loading
11
作者 J Jefferson Andrew Jabir Ubaid +4 位作者 Mohammed Ayaz Uddin Omar Waqas Saadi Kamran Ahmed Khan Rehan Umer Andreas Schiffer 《Defence Technology(防务技术)》 2026年第1期118-129,共12页
Low-velocity impact tests are carried out to explore the energy absorption characteristics of bio-inspired lattices,mimicking the architecture of the marine sponge organism Euplectella aspergillum.These sea sponge-ins... Low-velocity impact tests are carried out to explore the energy absorption characteristics of bio-inspired lattices,mimicking the architecture of the marine sponge organism Euplectella aspergillum.These sea sponge-inspired lattice structures feature a square-grid 2D lattice with double diagonal bracings and are additively manufactured via digital light processing(DLP).The collapse strength and energy absorption capacity of sea sponge lattice structures are evaluated under various impact conditions and are compared to those of their constituent square-grid and double diagonal lattices.This study demonstrates that sea sponge lattices can achieve an 11-fold increase in energy absorption compared to the square-grid lattice,due to the stabilizing effect of the double diagonal bracings prompting the structure to collapse layer-bylayer under impact.By adjusting the thickness ratio in the sea sponge lattice,up to 76.7%increment in energy absorption is attained.It is also shown that sea-sponge lattices outperform well-established energy-absorbing materials of equal weight,such as hexagonal honeycombs,confirming their significant potential for impact mitigation.Additionally,this research highlights the enhancements in energy absorption achieved by adding a small amount(0.015 phr)of Multi-Walled Carbon Nanotubes(MWCNTs)to the photocurable resin,thus unlocking new possibilities for the design of innovative lightweight structures with multifunctional attributes. 展开更多
关键词 Sea sponge-inspired lattice structures Additive manufacturing Energy absorption Low-velocity impact Lattice structure NANOCOMPOSITE
在线阅读 下载PDF
Enhanced electromagnetic wave absorption in biochar/yttrium iron garnet hybrid composites for electromagnetic interference shielding applications
12
作者 Ozgur Yasin Keskin 《International Journal of Minerals,Metallurgy and Materials》 2026年第1期335-346,共12页
Biochar and biochar composites are versatile materials that can be used in many applications.In this study,biochar was prepared from sawdust and combined with the yttrium iron garnet(YIG)nanocrystal to investigate the... Biochar and biochar composites are versatile materials that can be used in many applications.In this study,biochar was prepared from sawdust and combined with the yttrium iron garnet(YIG)nanocrystal to investigate the shielding effectiveness of the composite structure.Firstly,the effect of the pyrolysis temperature on the shielding effectiveness of biochar was investigated.Secondly,biochars combined with YIG nanocrystals with different contents and shielding effectiveness of the composites were investigated.The electromagnetic effectiveness of the samples was investigated within the X band(8-12 GHz).The findings indicate that biochar demonstrates enhanced absorption properties with elevated pyrolysis temperatures.Biochars demonstrated an approximate 40 d B shielding effectiveness,while YIG exhibited approximately 7 d B,corresponding to absorption at 8 GHz.However,the combination of biochar and YIG exhibited exceptional absorption,reaching 67.12 d B at 8 GHz. 展开更多
关键词 BIOCHAR electromagnetic shielding electromagnetic wave absorption COMPOSITE
在线阅读 下载PDF
Impedance-matchable 3D MXene sponge/NiFe@NC heterostructure with tunable pores for efficient electromagnetic wave absorption and thermal resistance
13
作者 Shuwen Tang Shen-Ao Cheng +3 位作者 Chi Yu Zhanming Wu Yu-Nan Tan Xiaojun Zeng 《Science China Materials》 2026年第3期1706-1718,共13页
The rapid advancement of 5G/6G communication and radar technology has exacerbated issues of electromagnetic wave(EMW)leakage,interference,and thermal management.Therefore,developing lightweight EMW absorbers that inte... The rapid advancement of 5G/6G communication and radar technology has exacerbated issues of electromagnetic wave(EMW)leakage,interference,and thermal management.Therefore,developing lightweight EMW absorbers that integrate strong absorption,broad bandwidth,and thermal stability is crucial.Herein,a 3D MXene sponge/NiFe@NC heterostructure with tunable pore architecture is constructed by pyrolyzing a polyurethane(PU)foam template uniformly coated with NiFe-decorated Ti_(3)C_(2)T_(x)MXene nanosheets.The resulting porous dielectric-magnetic network integrates interconnected MXene pathways with uniformly dispersed NiFe@NC nanoparticles,enabling a synergistic effect of dielectric-magnetic loss through conduction loss,dipole/interface polarization,and magnetic loss.Precise pore structure design enhances impedance matching and promotes multi-scattering and internal reflection of EMWs.Notably,an“EMW-pore matching”mechanism is proposed,whereby pore size governs the impedance matching at specific frequencies,enabling tunable absorption performance.The optimized absorber achieves a reflection loss(RL)of-67.84 dB,while radar cross-section(RCS)simulations confirm its exceptional attenuation and stealth potential.Additionally,the 3D skeleton derived from PU foam confers remarkable thermal resistance and flame retardancy.This pore-regulation strategy provides a scalable route to designing lightweight,broadband,and thermally stable EMW absorbers for next-generation communication and stealth applications. 展开更多
关键词 MXene sponge polyurethane foam pore matching electromagnetic wave absorption thermal resistance
原文传递
Energy absorption behavior of mild steel tube-core sandwich structures for rockfall protection
14
作者 HUANG Fuyou ZHANG Luqing +3 位作者 ZHOU Jian HAN Zhenhua WANG Song SUN Qihao 《Journal of Mountain Science》 2026年第1期171-187,共17页
Sandwich structures are widely favored for their lightweight,high strength and superior impact mitigation capabilities in blast mitigation and transportation safety applications.Their application in large-scale,high-e... Sandwich structures are widely favored for their lightweight,high strength and superior impact mitigation capabilities in blast mitigation and transportation safety applications.Their application in large-scale,high-energy rockfall protection remains limited due to their relatively low volumetric energy absorption efficiency and the complex fabrication processes of key energy-absorbing components.To address these limitations,this study proposes a novel sandwich structure incorporating mild steel tubes as core energy absorbers to efficiently mitigate highenergy rockfall impacts.A finite element model was developed in LS-DYNA to systematically investigate the deformation and energy absorption behaviors.Comprehensive parametric analyses were conducted to quantify the effects of key design variables,including tube wall thickness,tube spacing(number of tubes),and infill materials.The results demonstrate that increasing tube wall thickness significantly enhances ultimate energy absorption,with 12-mm-thick tubes absorbing 2.2 times more energy than 6-mm-thick tubes.Lateral constraints induced by adjacent tubes improve specific energy absorption per unit displacement by approximately 30%-45%.Furthermore,incorporating infill materials considerably enhances energy absorption,with aluminum foam infills achieving an 81%increase compared to empty tubes.Nevertheless,higher energy absorption capacity typically leads to greater peak impact forces,increasing the number of tubes offers a better balance between energy absorption and impact force,optimizing the structural performance.These findings provide valuable theoretical insights and practical guidelines for designing sandwich structures in civil and infrastructure engineering applications for effective rockfall protection. 展开更多
关键词 Sandwich structure Mild steel tube Rockfall impact Energy absorption Structural optimization
原文传递
A sustainable and high value-added strategy under lignite and waste silicon powder to construct SiC nanowires for electromagnetic wave absorption
15
作者 Wenhao Wang Xiaolin Lan +6 位作者 Haoquan Hao Jingxiang Liu Yong Shuai Qinghe Jing Shouqing Yan Jie Guo Zhijiang Wang 《International Journal of Minerals,Metallurgy and Materials》 2026年第1期347-356,共10页
The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbi... The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbide nanowires using lignite and waste silicon powder as raw materials through carbothermal reduction.The staggered structure of nanowires promotes the creation of interfacial polarization,impedance matching,and multiple loss mechanisms,leading to enhanced electromagnetic absorption performance.The silicon carbide nanowires demonstrate outstanding electromagnetic absorption capabilities with the minimum reflection loss of-48.09 d B at10.08 GHz and an effective absorption bandwidth(the reflection loss less than-10 d B)ranging from 8.54 to 16.68 GHz with a thickness of 2.17 mm.This research presents an innovative approach for utilizing solid waste in an environmentally friendly manner to produce broadband silicon carbide composite absorbers. 展开更多
关键词 LIGNITE waste silicon powder SiC nanowires electromagnetic wave absorption high value-added
在线阅读 下载PDF
Energy absorption properties and failure modes of flexible UHMWPE foam protective sandwich structure subjected to low-velocity impact
16
作者 Xiaoke Liu Kejing Yu Pengwan Chen 《Defence Technology(防务技术)》 2026年第2期32-48,共17页
Flexible materials play a crucial role in protecting against behind armour blunt trauma(BABT).However,their compliance complicates the understanding of failure mechanisms and energy absorption.This study used a combin... Flexible materials play a crucial role in protecting against behind armour blunt trauma(BABT).However,their compliance complicates the understanding of failure mechanisms and energy absorption.This study used a combined experimental and numerical approach to investigate the response and failure modes of a flexible ultra-high-molecular-weight polyethylene(UHMWPE)foam protective sandwich structure(UFPSS)under low-velocity impact(LVI).A finite element(FE)model,accounting for nonlinear large deformation and strain-rate-dependent material behavior,was developed for a woven-UFPSS(featuring a plain-woven fabric structure)subjected to a 50 J impact.Experimental and numerical results showed strong agreement in peak force(error<5%),maximum displacement(error<6%),and buffer time(error<8%).The impact's kinetic energy was mainly converted into internal energy of the fabric and foam materials(~50%),viscous dissipation in the foam core(12%-15%),frictional work at the contact interfaces(5%-6%),and work by the pneumatic fixture clamping force(~38%).This study provides the first investigation of the LVI performance of sandwich structures with all soft material layers,offering significant insights for the application of compliant materials in protective fields. 展开更多
关键词 Sandwich structure Ultra-high-molecular-weight polyethylene(UHMWPE) Low-velocity impact(LVI) Failure mode Energy absorption
在线阅读 下载PDF
Magnetic-Dielectric Synergy in One-Dimensional Metal Heterostructures for Enhanced Low-Frequency Microwave Absorption
17
作者 Feiyue Hu Peigen Zhang +10 位作者 Pei Ding Shuo Zhang Bingbing Fan Ali Saffar Shamshirgar Wei Zheng Wenwen Sun Longzhu Cai Haijiao Xie Qiyue Shao Johanna Rosen ZhengMing Sun 《Nano-Micro Letters》 2026年第5期371-390,共20页
Microwave absorption(MA)materials often face poor synergy between impedance matching and attenuation in the low-frequency range.Balancing permittivity and permeability through magnetic-dielectric synergy is a promisin... Microwave absorption(MA)materials often face poor synergy between impedance matching and attenuation in the low-frequency range.Balancing permittivity and permeability through magnetic-dielectric synergy is a promising strategy to address this issue.To realize the synergy,herein,Sn whiskers with an in situ oxide layer served as substrates for magnetic-loss-active CoNi nanosheet growth,forming a hierarchical CoNi@SnO_(2)@Sn(CNS)heterostructure.The CNS absorber achieves a minimum reflection loss(RL_(min))value of-62.29 dB with an effective absorption bandwidth(EAB)of 2.2 GHz,covering the entire C-band with 70%absorption at only 2.61 mm thickness.The nanosheet design of CoNi enhances magnetic anisotropy to promote natural resonance,while the conductive Sn core and abundant Sn/SnO_(2) and CoNi/SnO_(2) heterointerfaces facilitate conduction loss and dielectric polarization.When composited into a thermoplastic polyurethane(TPU)matrix,the resulting CNS/TPU-2 film(20 wt%CNS)exhibits an RL_(min) value of-61.04 dB and a 2.5 GHz EAB.Its in-plane and through-plane thermal conductivities reach 2.41 and 0.51 W m^(-1) K^(-1),representing 4.1 and 2.6 times those of pure TPU films,respectively,facilitating heat dissipation from protected devices.This work provides valuable insights into magnetic-dielectric synergy for low-frequency MA of 1D metal-based materials,offering promising potential for 5G communications and flexible electronics. 展开更多
关键词 Low frequency microwave absorption Magnetic-dielectric synergy MAX phase CoNi@SnO_(2)@Sn heterostructure Thermal conductivity
在线阅读 下载PDF
Directional Three‑Dimensional Macroporous Carbon Foams Decorated with WC_(1−x)Nanoparticles Derived from Salting‑Out Protein Assemblies for Highly Effective Electromagnetic Absorption
18
作者 Yongzheng Chen Lixue Gai +5 位作者 Bo Hu Yan Wang Yanyi Chen Xijiang Han Ping Xu Yunchen Du 《Nano-Micro Letters》 2026年第3期1-21,共21页
Directional three-dimensional carbon-based foams are emerging as highly attractive candidates for promising electromagnetic wave absorbing materials(EWAMs)thanks to their unique architecture,but their construction usu... Directional three-dimensional carbon-based foams are emerging as highly attractive candidates for promising electromagnetic wave absorbing materials(EWAMs)thanks to their unique architecture,but their construction usually involves complex procedures and extremely depends on unidirectional freezing technique.Herein,we propose a groundbreaking approach that leverages the assemblies of salting-out protein induced by ammonium metatungstate(AM)as the precursor,and then acquire directional three-dimensional carbon-based foams through simple pyrolysis.The electrostatic interaction between AM and protein ensures well dispersion of WC_(1−x)nanoparticles on carbon frameworks.The content of WC_(1−x)nanoparticles can be rationally regulated by AM dosage,and it also affects the electromagnetic(EM)properties of final carbon-based foams.The optimized foam exhibits exceptional EM absorption performance,achieving a remarkable minimum reflection loss of−72.0 dB and an effective absorption bandwidth of 6.3 GHz when EM wave propagates parallel to the directional pores.Such performance benefits from the synergistic effects of macroporous architecture and compositional design.Although there is a directional dependence of EM absorption,radar stealth simulation demonstrates that these foams can still promise considerable reduction in radar cross section with the change of incident angle.Moreover,COMSOL simulation further identifies their good performance in preventing EM interference among different electronic components. 展开更多
关键词 3D macroporous carbon-based foams Directional pore channels Salting-out protein assemblies EM wave absorption Directional dependence
在线阅读 下载PDF
Multiscale Design of Dual-Gradient Metamaterials Using Gel-Mediated 3D-Printed Graphene Aerogels for Broadband Electromagnetic Absorption
19
作者 Xiong Lv Changfeng Li +4 位作者 Ge Wang Diana Estevez Junjie Yang Qian Chen Faxiang Qin 《Nano-Micro Letters》 2026年第5期522-542,共21页
Three-dimensional(3D)-printedgraphene aerogels hold promise for electromagneticwave absorption(EWA)engineering due to itsultralow density,outstanding electromagnetic dissipationwith the flexibility and precision of ma... Three-dimensional(3D)-printedgraphene aerogels hold promise for electromagneticwave absorption(EWA)engineering due to itsultralow density,outstanding electromagnetic dissipationwith the flexibility and precision of manufacturingstrategies.However,their high conductivitycauses severe impedance mismatch,limiting EWAperformance.3D printing requirements also constrainthe dielectric properties of printable grapheneinks,hindering the integration of high-performanceabsorbers with advanced manufacturing.This studyproposes a polyacrylic acid(PAA)gel-mediated3D porous graphene oxide(GO)aerogel multiscaleregulation strategy.Precise gel content control enablesdual-gradient tuning of the rheology(Benefitingdirect ink writing(DIW))and dielectric loss(Enhancing EWA)of GO/PAA composites and reduces aerogel density(6.9 mg cm^(-3)from28.2 mg cm^(-3)).Thermal reduction decomposes PAA into amorphous carbon nanoparticles anchored on reduced graphene oxide(rGO),enhancingimpedance matching and absorption via synergistic 0D/2D interfacial polarization and conductive loss.The optimized rGO/PAA aerogelachieves a minimum reflection loss(RL)of-39.86 dB at 2.5 mm and an effective absorption bandwidth(EAB)of 8.36 GHz(9.64-18 GHz)at3.2 mm.Combining DIW and this aerogel,we design a metamaterial absorber(MA)with dual material(dielectric loss)and structural gradients.This MA exhibits an ultrawide EAB of 14 GHz(4-18 GHz)with a total thickness of 7.8 mm.This work establishes a coupled design paradigmof“composition-structure-performance,”providing an engineerable solution for developing lightweight,broadband EWA materials. 展开更多
关键词 Electromagnetic wave absorption Gel-mediated porous graphene aerogel Dual-gradient regulation Direct ink writing
在线阅读 下载PDF
Gyroid-structured SiOC composite with excellent broadband microwave absorption and load-bearing performance
20
作者 Hanjun Wei Siyu Chen +5 位作者 Zhiyong Chen Lu Tang Jimei Xue Cunxian Wang Zhijun Wang Ying Li 《Defence Technology(防务技术)》 2026年第1期277-288,共12页
Designing materials with both structural load-bearing capacity and broadband electromagnetic(EM)wave absorption properties remains a significant challenge.In this work,SiOC/SiC/SiO_(2)composite with gyroid structures ... Designing materials with both structural load-bearing capacity and broadband electromagnetic(EM)wave absorption properties remains a significant challenge.In this work,SiOC/SiC/SiO_(2)composite with gyroid structures were prepared through digital light processing(DLP)3D printing,polymer-derived ceramics(PDCs),chemical vapor infiltration(CVI),and oxidation technologies.The incorporation of the CVISiC phase effectively increases the dissipation capability,while the synergistic interaction between the gyroid structure and SiO_(2)phase significantly improves impedance matching performance.The SiOC/SiC/SiO_(2)composite achieved a minimum reflection loss(RL min)of-62.2 d B at 4.3 mm,and the effective absorption bandwidth(EAB)covered the X-band,with a thickness range of 4.1 mm-4.65 mm.The CST simulation results explain the broadband and low-frequency absorption characteristics,with an EAB of 8.4 GHz(9.6-18 GHz)and an RL min of-21.5 dB at 5 GHz.The excellent EM wave attenuation performance is associated primarily with polarization loss,conduction loss,the gyroid structure's enhancement of multiple reflections and scattering of EM waves,and the resonance effect between the structural units.The SiOC/SiC/SiO_(2)composite also demonstrated strong mechanical properties,with a maximum compressive failure strength of 31.6 MPa in the height direction.This work opens novel prospects for the development of multifunctional structural wave-absorbing materials suitable for broadband microwave absorption and load-bearing properties. 展开更多
关键词 Digital light processing Gyroid structure SiOC/SiC/SiO_(2)composite Microwave absorption Load-bearing properties
在线阅读 下载PDF
上一页 1 2 217 下一页 到第
使用帮助 返回顶部