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Protective performance of shear stiffening gel-modified foam against ballistic impact:Experimental and numerical study
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作者 Huan Tu Haowei Yang +9 位作者 Pengzhao Xu Zhe Yang Fan Tang Cheng Dong Yuchao Chen Lei Ren Wenjian Cao Chenguang Huang Yacong Guo Yanpeng Wei 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期510-520,共11页
As one of the most widely used personal protective equipment(PPE),body armors play an important role in protecting the human body from the high-velocity impact of bullets or projectiles.The body torso and critical org... As one of the most widely used personal protective equipment(PPE),body armors play an important role in protecting the human body from the high-velocity impact of bullets or projectiles.The body torso and critical organs of the wear may suffer severe behind-armor blunt trauma(BABT)even though the impactor is stopped by the body armor.A type of novel composite material through incorporating shear stiffening gel(STG)into ethylene-vinyl acetate(EVA)foam is developed and used as buffer layers to reduce BABT.In this paper,the protective performance of body armors composed of fabric bulletproof layers and a buffer layer made of foam material is investigated both experimentally and numerically.The effectiveness of STG-modified EVA in damage relief is verified by ballistic tests.In parallel with the experimental study,numerical simulations are conducted by LS-DYNA®to investigate the dynamic response of each component and capture the key mechanical parameters,which are hardly obtained from field tests.To fully describe the material behavior under the transient impact,the selected constitutive models take the failure and strain rate effect into consideration.A good agreement between the experimental observations and numerical results is achieved to prove the validity of the modelling method.The tests and simulations show that the impact-induced deformation on the human body is significantly reduced by using STG-modified EVA as the buffering material.The improvement of protective performance is attributed to better dynamic properties and more outstanding energy absorption capability of the composite foam. 展开更多
关键词 Ballistic behavior Composite foam Shear stiffening gel Finite element analysis protective mechanism
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Effect of Air Gap under Fabric on Thermal Protective Performance Using an Improved Apparatus 被引量:1
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作者 李小辉 卢业虎 +2 位作者 周亮 李俊 王云仪 《Journal of Donghua University(English Edition)》 EI CAS 2011年第6期595-598,共4页
The bench top test is one of the most important and effective methods to evaluate the total thermal protective performance(TPP) of firefighters' protective clothing,which is greatly influenced by the air gaps entr... The bench top test is one of the most important and effective methods to evaluate the total thermal protective performance(TPP) of firefighters' protective clothing,which is greatly influenced by the air gaps entrapped.In this paper,to investigate the effect of air gap width on TPP,a new improved apparatus with two height changeable buttons to hold the thermal sensor was developed to get a series of air gap sizes from 0 mm to 40 mm.The TPP of two types of flame-resistant outer fabrics was measured with TPP test apparatus respectively.Analysis of temperature rise with each air gap width was made to determine the effects of different air gaps on protective performance.It was indicated that air gap size had great effect on TPP of fabrics in the bench top test.An air gap width above 8 mm was suggested for the thermal protective clothing design. 展开更多
关键词 air gap thermal protective performance(TPP) bench top test firefig hter’s protective clothing
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Effect of Phase Change Materials on the Thermal Protective Performance of the Multi-layered Fabrics Examined by TPP Tester under Flash Fire 被引量:1
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作者 赵蒙蒙 李俊 《Journal of Donghua University(English Edition)》 EI CAS 2016年第1期150-154,共5页
Cotton fabrics treated with phase change materials( PCMs)were used in multi-layered fabrics of the fire fighter protective clothing to study its effect on thermal protection. The thermal protective performance( TPP) o... Cotton fabrics treated with phase change materials( PCMs)were used in multi-layered fabrics of the fire fighter protective clothing to study its effect on thermal protection. The thermal protective performance( TPP) of the multi-layered fabrics was measured by a TPP tester under flash fire. Results showed that the utilization of the PCM fabrics improved the thermal protective performance of the multi-layered fabrics. The fabric with a PCM add on of 41. 9% increased the thermal protection by 50. 6% and reduced the time to reach a second degree burn by 8. 4 s compared with the reference fabrics( without PCMs). The employment of the PCM fabrics also reduced the blackened areas on the inner layers. The PCM fabrics with higher PCM melting temperature could bring higher thermal protective performance. 展开更多
关键词 phase change material(PCM) multi-layered fabrics thermal protection performance(TPP) fire fighter protective clothing
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The protective performance of a molten salt frozen wall in the process of fluoride volatility of uranium
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作者 Jin-Hao Zhou Ji-Lin Tan +2 位作者 Bo Sun Qiang Dou Qing-Nuan Li 《Nuclear Science and Techniques》 SCIE CAS CSCD 2019年第6期138-146,共9页
The fluoride volatility method (FVM) is a technique tailored to separate uranium from fuel salt of molten salt reactors. A key challenge in R&D of the FVM is corrosion due to the presence of molten salt and corros... The fluoride volatility method (FVM) is a technique tailored to separate uranium from fuel salt of molten salt reactors. A key challenge in R&D of the FVM is corrosion due to the presence of molten salt and corrosive gases at high temperature. In this work, a frozen-wall technique was proposed to produce a physical barrier between construction materials and corrosive reactants. The protective performance of the frozen wall against molten salt was assessed using FLiNaK molten salt with introduced fluorine gas, which was regarded as a simulation of the FVM process. SS304, SS316L, Inconel 600 and graphite were chosen as the test samples. The extent of corrosion was characterized by an analysis of weight loss and scanning electron microscope studies. All four test samples suffered severe corrosion in the molten salt phase with the corrosion resistance as: Inconel 600>SS316L>graphite>SS304. The presence of the frozen wall could protect materials against corrosion by molten salt and corrosive gases, and compared with materials exposed to molten salt, the corrosion rates of materials protected by the frozen wall were decreased by at least one order of magnitude. 展开更多
关键词 MOLTEN SALT reactors FLUORIDE VOLATILITY method Corrosion FROZEN wall protective performance
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Protective Performance of Woven Fabrics against Heat Radiation
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作者 潘莺 《Journal of China Textile University(English Edition)》 EI CAS 2000年第1期103-105,共3页
In this paper,the protective performance of woven fab-rics against heat radiation is studied from the view offabric structure.As indices reflecting the protective per-formance against heat radiation,the heat emissivit... In this paper,the protective performance of woven fab-rics against heat radiation is studied from the view offabric structure.As indices reflecting the protective per-formance against heat radiation,the heat emissivity andthe transmissivity of different fabrics are measured.It ispointed out that structure changes of common textiles af-fect their transmission to heat radiation while have littleinfluence on their absorption or reflection to heat radi-ation except fabrics surfaces are aluminized.Double-layer weave is proved to be an effective fabric weave forreducing the trasmissivity.It helps increase the densityand tightness while keeps the comfort of woven fabrics atthe same time. 展开更多
关键词 HEAT radiation HEAT EMISSIVITY ABSORPTIVITY REFLECTIVITY TRANSMISSIVITY thermal protective clothing.
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Modeling Thermal Protective Performance of Multilayer Fabrics for Firefighters
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作者 崔志英 杨海燕 《Journal of Donghua University(English Edition)》 EI CAS 2011年第3期271-274,共4页
This paper is to report a prediction model for thermal protective performance of multilayer fabrics based on Matlab neural network toolbox. Then a back propagation (BP) neural network model is developed to predict the... This paper is to report a prediction model for thermal protective performance of multilayer fabrics based on Matlab neural network toolbox. Then a back propagation (BP) neural network model is developed to predict thermal protective performance of multilayer fabrics for firefighters. The network consists of twelve input nodes, six hidden nodes, and one output node. The inputs are weight, thickness, density of warp and weft, limited oxygen index (LOI), and heat conductivity of each-layer fabric. Thermal protective performance (TPP) rating of multilayer fabrics is the output. In this paper, the data from the experiments are used as learning information for the neural network to develop a reliable prediction model. Finnally the model performance is verified, and the proposed model can be applied to predict the thermal protective performance of multilayer fabrics for firefighters. 展开更多
关键词 消防人员衣服 预言模型 热保护的性能(TPP ) 多层的织物 BP 神经网络
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Effects of thinning on the understory light environment of different stands and the photosynthetic performance and growth of the reforestation species Phoebe bournei
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作者 Shicheng Su Nianqing Jin Xiaoli Wei 《Journal of Forestry Research》 SCIE EI CAS CSCD 2024年第1期12-28,共17页
Light levels determine regeneration in stands and a key concern is how to regulate the light environment of different stand types to the requirements of the understory.In this study,we selected three stands typical in... Light levels determine regeneration in stands and a key concern is how to regulate the light environment of different stand types to the requirements of the understory.In this study,we selected three stands typical in south China(a Cryptomeria japonica plantation,a Quercus acutissima plantation,and a mixed stand of both)and three thinning intensities to determine the best understory light environ-ment for 3-year-old Phoebe bournei seedlings.The canopy structure,understory light environment,and photosynthe-sis and growth indicators were assessed following thin-ning.Thinning improved canopy structure and understory light availability of each stand;species composition was the reason for differences in the understory light environ-ment.Under the same thinning intensity,the mixed stand had the greatest light radiation and most balanced spectral composition.P.bournei photosynthesis and growth were closely related to the light environment;all three stands required heavy thinning to create an effective and sustained understory light environment.In a suitable understory light environment,the efficiency of light interception,absorption,and use by seedlings was enhanced,resulting in a higher carbon assimilation the main limiting factor was stomatal conductance.As a shade-avoidance signal,red/far-red radia-tion is a critical factor driving changes in photosynthesis and growth of P.bournei seedlings,and a reduction increased light absorption and use capacity and height:diameter ratios.The growth advantage transformed from diameter to height,enabling seedlings to access more light.Our findings suggest that the regeneration of shade-tolerant species such as P.bournei could be enhanced if a targeted approach to thinning based on stand type was adopted. 展开更多
关键词 THINNING Understory light environment Phoebe bournei Photosynthetic performance Growth performance
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Hydroxytyrosol and Parkinson's disease:protective actions against alpha-synuclein toxicity
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作者 Ruth Hornedo-Ortega Ana M.Espinosa-Oliva 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第7期1427-1428,共2页
Parkinson’s disease:Parkinson’s disease(PD) is the second most prevalent neurodegenerative disease,after Alzheimer’s disease,affecting 1%of the general population over the age of 65years.According to data from the ... Parkinson’s disease:Parkinson’s disease(PD) is the second most prevalent neurodegenerative disease,after Alzheimer’s disease,affecting 1%of the general population over the age of 65years.According to data from the World Health Organization(WHO),its prevalence has doubled in the past 25 years.In 2019,global estimates indicated over 8.5 million individuals with PD and it is suggested that PD caused 329000 deaths,an increase of over 100% since 2000(WHO,2022). 展开更多
关键词 protective ALZHEIMER PREVALENCE
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Ambroxol,the cough expectorant with neuroprotective effects
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作者 Kristin Patzwaldt Salvador Castaneda-Vega 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第11期2345-2346,共2页
Ambroxol hydrochloride(2-amino-3,5-dibromo-N-methylbenzylamine hydrochloride)has been used as a mucolytic agent in the treatment of respiratory diseases since the late 1970s.Its effects on mucus membranes such as mucu... Ambroxol hydrochloride(2-amino-3,5-dibromo-N-methylbenzylamine hydrochloride)has been used as a mucolytic agent in the treatment of respiratory diseases since the late 1970s.Its effects on mucus membranes such as mucus disruption,increased mucus production,and low toxicity profile were addressed in its original German patent in 1966.These first described properties have kept Ambroxol available worldwide and over the counter in the pharmaceutical market to this day. 展开更多
关键词 protective AGENT GERMAN
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Semi-hydro-equivalent design and performance extrapolation between 100 kJ-scale and NIF-scale indirect drive implosion
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作者 Huasen Zhang Dongguo Kang +5 位作者 Changshu Wu Liang Hao Hao Shen Shiyang Zou Shaoping Zhu Yongkun Ding 《Matter and Radiation at Extremes》 SCIE EI CSCD 2024年第1期25-34,共10页
Extrapolation of implosion performance between different laser energy scales is investigated for indirect drive through a semi-hydroequivalent design.Since radiation transport is non-hydro-equivalent,the peak radiatio... Extrapolation of implosion performance between different laser energy scales is investigated for indirect drive through a semi-hydroequivalent design.Since radiation transport is non-hydro-equivalent,the peak radiation temperature of the hohlraum and the ablation velocity of the capsule ablator are not scale-invariant when the sizes of the hohlraum and the capsule are scale-varied.A semi-hydro-equivalent design method that keeps the implosion velocity V_(i),adiabat α_(F),and P_(L)/R_(hc)^(2) (where P_(L) is the laser power and R_(hc) is the hohlraum and capsule scale length)scale-invariant,is proposed to create hydrodynamically similar implosions.The semi-hydro-equivalent design and the scaled implosion performance are investigated for the 100 kJ Laser Facility(100 kJ-scale)and the National Ignition Facility(NIF-scale)with about 2 MJ laser energy.It is found that the one-dimensional implosion performance is approximately hydro-equivalent when V_(i) and α_(F) are kept the same.Owing to the non-hydro-equivalent radiation transport,the yield-over-clean without α-particle heating(YOC_(noα))is slightly lower at 100 kJ-scale than at NIF-scale for the same scaled radiation asymmetry or the same initial perturbation of the hydrodynamic instability.The overall scaled two-dimensional implosion performance is slightly lower at 100 kJ-scale.The general Lawson criterion factor scales asχ_(noα) ^(2D)∼S^(1.06±0.04)(where S is the scale-variation factor)for the semi-hydro-equivalent implosion design with a moderate YOC_(noα).Our study indicates that χ_(noα)≈0.379 is the minimum requirement for the 100 kJ-scale implosion to demonstrate the ability to achieve marginal ignition at NIF-scale. 展开更多
关键词 performance transport slightly
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Experimental and numerical study on protective effect of RC blast wall against air shock wave
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作者 Xin-zhe Nian Quan-min Xie +2 位作者 Xin-li Kong Ying-kang Yao Kui Huang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期567-579,共13页
Prototype experiments were carried out on the explosion-proof performance of the RC blast wall.The mass of TNT detonated in the experiments is 5 kg and 20 kg respectively.The shock wave overpressure was tested in diff... Prototype experiments were carried out on the explosion-proof performance of the RC blast wall.The mass of TNT detonated in the experiments is 5 kg and 20 kg respectively.The shock wave overpressure was tested in different regions.The above experiments were numerically simulated,and the simulated shock wave overpressure waveforms were compared with that tested and given by CONWEP program.The results show that the numerically simulated waveform is slightly different from the test waveform,but similar to CONWEP waveform.Through dimensional analysis and numerical simulation under different working conditions,the equation for the attenuation rate of the diffraction overpressure behind the blast wall was obtained.According to the corresponding standards,the degree of casualties and the damage degree of the brick concrete building at a certain distance behind the wall can be determined when parameters are set.The above results can provide a reference for the design and construction of the reinforced concrete blast wall. 展开更多
关键词 Blast wall Shock wave DIFFRACTION OVERPRESSURE Protection
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Impact of Dietary Lactobacillus plantarum Postbiotics on the Performance of Layer Hens under Heat Stress Conditions
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作者 Mohamad Farran Bouchra El Masry +1 位作者 Zeinab Kaouk Houssam Shaib 《Open Journal of Veterinary Medicine》 CAS 2024年第3期39-55,共17页
This experiment was conducted to determine the performance of heat-stressed layers fed a diet containing the probiotic Lactobacillus plantarum RS5 or its products of fermentation (postbiotics). Twenty-week-old Isa Whi... This experiment was conducted to determine the performance of heat-stressed layers fed a diet containing the probiotic Lactobacillus plantarum RS5 or its products of fermentation (postbiotics). Twenty-week-old Isa White layers, were subdivided into six treatments of 32 individually caged birds. Half of the birds were reared under regular temperature conditions, while the other half was subjected to cyclic daily heat stress. Layers were offered one of three diets: 1) Control;2) Control + Lactobacillus plantarum RS5 probiotic;3) Control + Lactobacillus plantarum RS5 postbiotics. Birds were tested for performance and visceral organ development for 5 months. Heat stress negatively affected the birds’ feed intake, egg weight, shell weight percentage, Haugh unit, shell thickness, yolk color, body weight and spleen weight percentage. Postbiotics significantly increased egg production (p < 0.05) in comparison to the control and the probiotic fed group (94.8% vs 92.6% vs 93.1%, respectively). Birds under probiotic or postbiotic diet showed a significantly higher (p < 0.05) feed intake and egg weight, although the probiotic had a more pronounced and gradual effect. Specific gravity, yolk weight percentage and shell thickness didn’t show differences among dietary groups. The Haugh Unit was significantly higher (p < 0.05) in probiotic group which also showed a significantly lower yolk color index (p < 0.05). The different feed treatments did not impact the bird’s viscera weight percentage, except for the ileum that was significantly lower (p < 0.05) under postbiotic supplementation. Both probiotics and postbiotics could be used as a potential growth promoters and might alleviate heat stress impact in poultry industry. 展开更多
关键词 Lactobacillus plantarum LAYERS Heat Stress Postbiotic PROBIOTICS performance
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Two-Way Neural Network Performance PredictionModel Based onKnowledge Evolution and Individual Similarity
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作者 Xinzheng Wang Bing Guo Yan Shen 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第2期1183-1206,共24页
Predicting students’academic achievements is an essential issue in education,which can benefit many stakeholders,for instance,students,teachers,managers,etc.Compared with online courses such asMOOCs,students’academi... Predicting students’academic achievements is an essential issue in education,which can benefit many stakeholders,for instance,students,teachers,managers,etc.Compared with online courses such asMOOCs,students’academicrelateddata in the face-to-face physical teaching environment is usually sparsity,and the sample size is relativelysmall.It makes building models to predict students’performance accurately in such an environment even morechallenging.This paper proposes a Two-WayNeuralNetwork(TWNN)model based on the bidirectional recurrentneural network and graph neural network to predict students’next semester’s course performance using only theirprevious course achievements.Extensive experiments on a real dataset show that our model performs better thanthe baselines in many indicators. 展开更多
关键词 COMPUTER EDUCATION performance prediction deep learning
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Dietary supplementation of laminarin improves the reproductive performance of sows and the growth of suckling piglets
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作者 Pengguang Zhang Guoyuan Jiang +6 位作者 Chenghong Ma Yubo Wang Enfa Yan Linjuan He Jianxin Guo Xin Zhang Jingdong Yin 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2024年第1期329-343,共15页
Background Maternal nutrition is essential in keeping a highly efficient production system in the pig industry.Laminarin has been shown to improve antioxidant capacity,reduce the inflammatory response,and favor the ho... Background Maternal nutrition is essential in keeping a highly efficient production system in the pig industry.Laminarin has been shown to improve antioxidant capacity,reduce the inflammatory response,and favor the homeostasis of intestinal microbiota.However,the effect of dietary supplementation of laminarin on the reproductive performance of sows and the growth of suckling offspring remains unknown.Methods A total of 40 Landrace×Yorkshire multiparous sows on d 85 of gestation,similar in age,body weight(BW),parity and reproductive performance,were randomly divided into four dietary treatments with 10 sows per treatment,receiving a control diet(basal pregnancy or lactating diets)and a basal diet supplemented with 0.025%,0.05%and 0.10%laminarin,respectively.The experiment lasted from d 85 of gestation to d 21 of lactation.Results Laminarin supplementation linearly increased number born alive per litter(P=0.03),average daily feed intake(ADFI,P<0.01),and total milk yield of sows during the lactation of 1–21 d(P=0.02).Furthermore,maternal laminarin supplementation increased the average daily gain(ADG)of piglets while tending to reduce the culling and death rate before weaning.In addition,alterations to the composition of colostrum and milk,as well as to serum inflammatory cytokines and immunoglobulins of sows were observed.The fecal microbiota profile of sows supported the improvement of reproductive performance in sows and the growth performance in suckling offspring.Conclusions Dietary supplementation of laminarin during late pregnancy and lactation could significantly improve reproductive performance of sows and growth performance of piglets. 展开更多
关键词 Fecal microbiota LAMINARIN MILK PIGLETS Reproductive performance SOWS
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Effect of Molecular Weight on Thermoelectric Performance of P3HT Analogues with 2-Propoxyethyl Side Chains
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作者 董得福 WANG Wei +3 位作者 ZHAN Chun LI Chenglong ZHOU Qisheng 肖生强 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第2期268-281,共14页
By replacing hexyl chains in poly(3-hexylthiophene)(P3HT)with 2-propoxyethyls,four poly(3-(2-propoxyethyl)thiophene)(P3POET)homopolymers with comparable polydispersity indexes(PDI)and regioregularities were prepared h... By replacing hexyl chains in poly(3-hexylthiophene)(P3HT)with 2-propoxyethyls,four poly(3-(2-propoxyethyl)thiophene)(P3POET)homopolymers with comparable polydispersity indexes(PDI)and regioregularities were prepared herein in addition with step increment of about 7 kDa on numberaverage molecular weight(M_(n))from around 11 to 32 kDa(accordingly denoted as P11k,P18k,P25k,and P32k).When doped in film by FeCl_(3)at the optimized conditions,the maximum power factor(PF_(max))increases greatly from 4.3μW·m^(-1)·K^(-2)for P11k to 8.8μW·m^(-1)·K^(-2)for P18k,and further to 9.7μW·m^(-1)·K^(-2)for P25k,followed by a slight decrease to 9.2μW·m^(-1)·K^(-2)for P32k.The close Seebeck coefficients(S)at PF_(max)are observed in these doped polymer films due to their consistent frontier orbital energy levels and Fermi levels.The main contribution to this PF_(max)evolution thus comes from the corresponding conductivities(σ).Theσvariation of the doped films can be rationally correlated with their microstructure evolution. 展开更多
关键词 conjugated polymer molecular weight MICROSTRUCTURE thermoelectric performance
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Elliptical encirclement control capable of reinforcing performances for UAVs around a dynamic target
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作者 Fei Zhang Xingling Shao +1 位作者 Yi Xia Wendong Zhang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期104-119,共16页
Most researches associated with target encircling control are focused on moving along a circular orbit under an ideal environment free from external disturbances.However,elliptical encirclement with a time-varying obs... Most researches associated with target encircling control are focused on moving along a circular orbit under an ideal environment free from external disturbances.However,elliptical encirclement with a time-varying observation radius,may permit a more flexible and high-efficacy enclosing solution,whilst the non-orthogonal property between axial and tangential speed components,non-ignorable environmental perturbations,and strict assignment requirements empower elliptical encircling control to be more challenging,and the relevant investigations are still open.Following this line,an appointed-time elliptical encircling control rule capable of reinforcing circumnavigation performances is developed to enable Unmanned Aerial Vehicles(UAVs)to move along a specified elliptical path within a predetermined reaching time.The remarkable merits of the designed strategy are that the relative distance controlling error can be guaranteed to evolve within specified regions with a designer-specified convergence behavior.Meanwhile,wind perturbations can be online counteracted based on an unknown system dynamics estimator(USDE)with only one regulating parameter and high computational efficiency.Lyapunov tool demonstrates that all involved error variables are ultimately limited,and simulations are implemented to confirm the usability of the suggested control algorithm. 展开更多
关键词 Elliptical encirclement Reinforced performances Wind perturbations UAVS
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Effects of Additives on the Microstructure and Tribology Performance of Ta-12W Alloy Micro-Arc Oxidation Coating
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作者 刘玲 HU Changgang +1 位作者 CHENG Wendong 刘兴泉 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第1期142-149,共8页
Oxide ceramic coatings were fabricated on tantalum alloys by micro-arc oxidation (MAO) to improve their hardness and tribological properties. The MAO coatings were manufactured in a mixed silicatephosphate electrolyte... Oxide ceramic coatings were fabricated on tantalum alloys by micro-arc oxidation (MAO) to improve their hardness and tribological properties. The MAO coatings were manufactured in a mixed silicatephosphate electrolyte containing NaF and/or EDTA (ethylene diamine tetraacetic acid). The surface morphology,cross-sectional view, chemical composition, hardness, and wear performance of the coatings were analysed. As revealed by the scanning electron microscopy, silica-rich nodules appear on the MAO coating obtained in the silicate-phosphate electrolyte, but the formation of nodules is inhibited with NaF and/or EDTA in the electrolyte.Also, they reduce the roughness and improve the compactness of the coatings, which are composed of Ta_(2)O_(5),(Ta, O), and TaO. A thick and hard coating is obtained in the NaF-containing electrolyte, and the tribology performance is effectively improved. With additives, the nodule structure is detached from the coating surface and dissolved in the electrolyte. By using NaF as an electrolyte additive, the abrasion performance of the MAO coating is enhanced by decreasing the nodule structure, increasing the size of micropores, and improving the coating hardness. 展开更多
关键词 micro-arc oxidation tantalum alloy ADDITIVES tribology performance
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Adaptive admittance tracking control for interactive robot with prescribed performance
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作者 MENG Qingrui LIN Yan 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第2期444-450,共7页
An adaptive control approach is presented in this paper for tracking desired trajectories in interactive manipulators. The controller design incorporates prescribed performance functions (PPFs) to improve dynamic perf... An adaptive control approach is presented in this paper for tracking desired trajectories in interactive manipulators. The controller design incorporates prescribed performance functions (PPFs) to improve dynamic performance. Notably, the performance of the output error is confined in an envelope characterized by exponential convergence, leading to convergence to zero. This feature ensures a prompt response from admittance control and establishes a reliable safety framework for interactions. Simulation results provide practical insights,demonstrating the viability of the control scheme proposed in this paper. 展开更多
关键词 prescribed performance admittance control adaptive control ROBOTS
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Study of the Ballistic Impact Behavior of Protective Multi-Layer Composite Armor
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作者 Dongsheng Jia Yingjie Xu +2 位作者 Liangdi Wang Jihong Zhu Weihong Zhang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第7期171-199,共29页
The abalone shell,a composite material whose cross-section is composed of inorganic and organic layers,has high strength and toughness.Inspired by the abalone shell,several multi-layer composite plates with different ... The abalone shell,a composite material whose cross-section is composed of inorganic and organic layers,has high strength and toughness.Inspired by the abalone shell,several multi-layer composite plates with different layer sequences and thicknesses are studied as bullet-proof material in this paper.To investigate the ballistic performance of this multi-layer structure,the complete characterization model and related material parameters of large deformation,failure and fracture ofAl_(2)O_(3)ceramics andCarbon Fiber Reinforced Polymer(CFRP)are studied.Then,3D finite element models of the proposed composite plates with different layer sequences and thicknesses impacted by a 12.7 mm armor-piercing incendiary(API)are built using Abaqus to predict failure.The simulation results show that the CFRP/Al2O3 ceramic/Ultrahigh Molecular Weight Polyethylene(UHMWPE)/CFRP(1 mm/4 mm/4 mm/1 mm)composite is the optimized stack of layers.The simulation results under specified layer sequence and thickness have a reasonable correlation with the experimental results and reflect the failure and fracture of the multi-layer composite protective armor. 展开更多
关键词 protective armor COMPOSITE bionic design structure design mechanical property
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Chemical modification of barite for improving the performance of weighting materials for water-based drilling fluids
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作者 Li-Li Yang Ze-Yu Liu +3 位作者 Shi-bo Wang Xian-Bo He Guan-Cheng Jiang Jie Zhang 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期551-566,共16页
With increasing drilling depth and large dosage of weighting materials,drilling fluids with high solid content are characterized by poor stability,high viscosity,large water loss,and thick mud cake,easier leading to r... With increasing drilling depth and large dosage of weighting materials,drilling fluids with high solid content are characterized by poor stability,high viscosity,large water loss,and thick mud cake,easier leading to reservoir damage and wellbore instability.In this paper,micronized barite(MB)was modified(mMB)by grafting with hydrophilic polymer onto the surface through the free radical polymerization to displace conventional API barite partly.The suspension stability of water-based drilling fluids(WBDFs)weighted with API barite:mMB=2:1 in 600 g was significantly enhanced compared with that with API barite/WBDFs,exhibiting the static sag factor within 0.54 and the whole stability index of 2.The viscosity and yield point reached the minimum,with a reduction of more than 40%compared with API barite only at the same density.Through multi-stage filling and dense accumulation of weighting materials and clays,filtration loss was decreased,mud cake quality was improved,and simultaneously it had great reservoir protection performance,and the permeability recovery rate reached 87%.In addition,it also effectively improved the lubricity of WBDFs.The sticking coefficient of mud cake was reduced by 53.4%,and the friction coefficient was 0.2603.Therefore,mMB can serve as a versatile additive to control the density,rheology,filtration,and stability of WBDFs weighted with API barite,thus regulating comprehensive performance and achieving reservoir protection capacity.This work opened up a new path for the productive drilling of extremely deep and intricate wells by providing an efficient method for managing the performance of high-density WBDFs. 展开更多
关键词 Drilling fluids Weighting materials Filtration control Reservoir protection Stability property
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