Lightweight Dual‑Functional Segregated Nanocomposite Foams for Integrated Infrared Stealth and Absorption‑Dominant Electromagnetic Interference Shielding

Lightweight infrared stealth and absorption-dominant electromagnetic interference(EMI)shielding materials are highly desirable in areas of aerospace,weapons,military and wearable electronics.Herein,lightweight and high-efficiency dual-functional segregated nanocomposite foams with microcellular structures are developed for integrated infrared stealth and absorption-dominant EMI shielding via the efficient and scalable supercritical CO_(2)(SC-CO_(2))foaming combined with hydrogen bonding assembly and compression molding strategy.The obtained lightweight segregated nanocomposite foams exhibit superior infrared stealth performances benefitting from the synergistic effect of highly effective thermal insulation and low infrared emissivity,and outstanding absorption-dominant EMI shielding performances attributed to the synchronous construction of microcellular structures and segregated structures.Particularly,the segregated nanocomposite foams present a large radiation temperature reduction of 70.2℃ at the object temperature of 100℃,and a significantly improved EM wave absorptivity/reflectivity(A/R)ratio of 2.15 at an ultralow Ti_(3)C_(2)T_(x) content of 1.7 vol%.Moreover,the segregated nanocomposite foams exhibit outstanding working reliability and stability upon dynamic compression cycles.The results demonstrate that the lightweight and high-efficiency dual-functional segregated nanocomposite foams have excellent potentials for infrared stealth and absorption-dominant EMI shielding applications in aerospace,weapons,military and wearable electronics.

Fabrication of segregated poly(arylene sulfide sulfone)/graphene nanoplate composites reinforced by polymer fibers for electromagnetic interference shielding

Poly(arylene sulfide sulfone)/graphene nanoplate(PASS/GNP) composites with segregated structure based on continuous polymer fiber skeletons were fabricated by coating a thin conductive layer on the PASS fibers and then performing compression molding. The formation of a unique segregated conductive network endowed the PASS/GNP composites with high electrical conductivity and excellent electromagnetic interference(EMI) shielding effectiveness(SE), reaching 17.8 S/m and 30.1 d B, respectively, when the content of the GNPs in the conductive layer was 20 wt%. The PASS/GNP composites also exhibited outstanding mechanical properties, which was attributed to the continuous PASS fiber skeletons that could withstand large loads and the strong interfacial interaction between the conductive layers and the PASS fibers that could provide good stress transfer. This approach is suitable for most soluble polymers.

Ge Complementary Tunneling Field-Effect Transistors Featuring Dopant Segregated NiGe Source/Drain

Ge complementary tunneling field-effect transistors（TFETs） are fabricated with the NiGe metal source/drain（S/D） structure. The dopant segregation method is employed to form the NiGe/Ge tunneling junctions of sufficiently high Schottky barrier heights. As a result, the Ge p-and n-TFETs exhibit decent electrical properties of large ON-state current and steep sub-threshold slope（S factor）. Especially, I_d of 0.2 μA/μm is revealed at V_g-V_（th） = V_d = ±0.5 V for Ge pTFETs,with the S factor of 28 mV/dec at 7 K.

Simulation of Solid Particle Interactions Including Segregated Lamination by Using MPS Method

A new MPS(Moving Particle Semi-implicit)method is developed to simulate the behaviors and interactions of multiple fine solid particles as a continuum.As fluid particles are affected by viscosity,so solid particles are affected by friction.The solid particle dynamics for landslides,dumping,and gravity sorting etc.which can be difficult to simulate using conventional MPS methods,are modeled in this paper using the developed multi-solid-particle MPS method that benefits from drawing comparisons with the corresponding fluid particle behaviors.The present MPS results for dumping solid particles are verified against the corresponding DEM(Discrete Element Method)results.The shape and angle of repose for solid particles are shown to be highly dependent on the friction coefficient between grains.The peculiar phenomenon of segregated lamination(gravity sorting)among grains of different densities has been successfully reproduced using the multi-solid-particle MPS method.Lamination quality is found to be dependent on the densities and frictional coefficients of the constituent particles.The behavior of heterogeneous mixtures of multiple solid and liquid particles are also compared and discussed.This newly developed tool offers a window into the physical dynamics of sedimentology that the broader geoscience community might benefit from.

SEGREGATED VECTOR SOLUTIONS FOR NONLINEAR SCHR?DINGER SYSTEMS IN R^2

We study the following nonlinear Schrodinger system{-△u＋P（｜x｜）u=μu^3＋βv^2u,x∈R^2, -△v＋Q（｜x｜）v=υv^3＋βu^2v,x∈R^2,where P（r） and Q（r） are positive radial functions, μ〉 0, υ 〉 0, and 3 E R is a coupling constant. This type of system arises, particularly, in models in Bose-Einstein condensates theory. Applying a finite reduction method, we construct an unbounded sequence of nonradial positive vector solutions of segregated type when β is in some suitable interval, which gives an answer to an interesting problem raised by Peng and Wang in Remark 4.1 （Arch. Ration. Mech. Anal., 208（2013）, 305-339）.

Segregated Distribution of Liriope tetraphylla, Aglaura hemistoma and Nausithoe punctata (Cnidaria) in the Southern Gulf of Mexico

In order to study the segregated distribution of the three most abundant jellyfish species in the southern Gulf of Mexico, a total of 85 stations were sampled during an oceanographic cruise from 19 May to 18 June 2006. Trawling took place from surface to a maximum depth of 200 m, using a Bongo net with a 61 cm mouth diameter and 333 and 500 μm mesh sizes. Temperature and salinity were recorded. Samples were preserved in 4% formalin, neutralized with sodium borate, and changed to 70% ethylic alcohol after 24 hours for conservation. The jellyfish data were standardized to 100 m3 of filtered water. A total of 10,610 jellyfish were collected from the 333 μm mesh size net, of which eight species represented 88.49% of the total density: Aglaura hemistoma, Liriope tetraphylla, Nausithoe punctata, Clytia hemisphaerica, Persa incolorata, Obelia spp., Clytia folleata and Eutima gracilis. The former three species are the subject of this study. The results obtained indicate that the high density areas of these three species have a segregated distribution. Segregation values (White’s index) recorded between pairs of specie were very high: L. tetraphylla - A. hemistoma, 0.88;L. tetraphylla - N. punctata, 0.86 and A. hemistoma - N. punctata, 0.84. The spatial distribution of the high density areas of these species fits well with the three hydrodynamically different areas: A. hemistoma in Campeche Bank, L. tetraphylla on the Campeche and Tabasco shelves and N. punctata in Campeche Bay. This spatial distribution pattern corresponds to their main habitat and reproductive habits of the species, as well as the influence of the hydrodynamics that dominate each area.

Visualization of flow behavior in ore-segregated packed beds with fine interlayers

Ore particles,especially fine interlayers,commonly segregate in heap stacking,leading to undesirable flow paths and changeable flow velocity fields of packed beds.Computed tomography(CT),COMSOL Multiphysics,and MATLAB were utilized to quantify pore structures and visualize flow behavior inside packed beds with segregated fine interlayers.The formation of fine interlayers was accompanied with the segregation of particles in packed beds.Fine particles reached the upper position of the packed beds during stacking.CT revealed that the average porosity of fine interlayers(24.21%)was significantly lower than that of the heap packed by coarse ores(37.42%),which directly affected the formation of flow paths.Specifically,the potential flow paths in the internal regions of fine interlayers were undeveloped.Fluid flowed and bypassed the fine interlayers and along the sides of the packed beds.Flow velocity also indicated that the flow paths easily gathered in the pore throat where flow velocity(1.8×10^-5 m/s)suddenly increased.Fluid stagnant regions with a flow velocity lower than 0.2×10^-5 m/s appeared in flow paths with a large diameter.

Safety assessment of approximate segregated parallel operation on closely spaced parallel runways

With the continuous growth of air traffic flow, some airports in China or other countries begin to construct Closely Spaced Parallel Runways(CSPR) to meet the capacity requirement of civil aviation. In this paper, the simulation and calculation method of flight trajectory is developed,as well as the collision risk calculation method and wake vortex encounter risk calculation method.New methods for departure and go-around procedures are proposed to achieve approximate segregated parallel operation in an attempt to obtain approximately the same results on closely spaced parallel runways as on widely spaced parallel runways. By comparing with the independent parallel departure and segregated parallel operation in ICAO Doc. 9643, it is found that the lateral separation between aircraft in this proposal is not less than the separations in the other two cases. Based on the simulation calculation of flight trajectories under different conditions, the probabilities of collision conflict and encountering wake vortex are lower than those in current operation plan.The proposed plan has no special requirements in pilot operation, control command procedures,airport facilities, or meteorological observation and prediction, so it is convenient to promote and implement at the airports with closely spaced parallel runways.

Genetic mapping of folate QTLs using a segregated population in maizeFA

As essential B vitamin for humans, folates accumulation in edible parts of crops, such as maize kernels, Is of great importance for human health. But its breeding is always limited by the prohibitive cost of folate profiling. The molecular breeding is a more executable and efficient way for folate fortification, but is limited by the molecular knowledge of folate regulation. Here we report the genetic mapping of folate quantitative trait loci (QTLs) using a segregated population crossed by two maize lines, one high in folate (GEMS31) and the other low in folate (DAN3130). Two folate QTLs on chromosome 5 were obtained by the combination of F2 whole-exome sequencing and F3 kernel-folate profiling. These two QTLs had been confirmed by bulk segregant analysis using F6 pooled DNA and F7 kernel-folate profiling, and were overlapped with QTLs identified by another segregated population. These two QTLs contributed 41.6% of phenotypic variation of 5-formyltetrahydrofolate, the most abundant storage form among folate derivatives in dry maize grains, in the GEMS31×DAN3130 population. Their fine mapping and functional analysis will reveal details of folate metabolism, and provide a basis for marker-assisted breeding aimed at the enrichment of folates in maize kernels.

Towards Efficient Electromagnetic Interference Shielding Performance for Polyethylene Composites by Structuring Segregated Carbon Black/Graphite Networks

An electromagnetic interference （EMI） shielding composite based on ultrahigh molecular weight polyethylene （UHMWPE） loaded with economical graphite-carbon black （CB） hybrid fillers was prepared via a green and facile methodology, i.e., high-speed mechanical mixing combined with hot compression thus avoiding the assistance of the intensive ultrasound dispersion in volatile organic solvents. In this composite, the graphite-CB hybrid fillers were selectively distributed in the interfacial regions of UHMWPE domains resulting a typical segregated structure. Thanks to the specific morphology of segregated conductive networks along with the synergetic effect of large-sized graphite flakes and small-sized CB nanoparticles, a low filler loading of 7.7 vol% （15 wt%） yielded the graphite-CB/UHMWPE composites with a satisfactory electrical conductivity of 33.9 S/m and a superior shielding effectiveness of 40.2 dB, manifesting the comparable value of the pricey large-aspect-ratio carbon nanofillers （e.g., carbon nanotubes and graphene nanosheets） based polymer composites. More interestingly, with the addition of 15 wt% graphite-CB （1/3, W/W） hybrid fillers, the tensile strength and elongation at break of the composite reached 25.3 MPa and 126%, respectively; with a remarkable increase of 58.1% and 2420% over the conventional segregated graphite/UHMWPE composites. The mechanical reinforcement could be attributed to the favor of the small-sized CB particles in the polymer molecular diffusion between UHMWPE domains which in tuna provided a stronger interfacial adhesion. This work provides a facile, green and affordable strategy to obtain the polymer composites with high electrical conductivity, efficient EMI shielding, and balanced mechanical performance.

Magnetic-electric composite coating with oriented segregated structure for enhanced electromagnetic shielding

Manipulation of the internal architecture is essential for electromagnetic interference(EMI)shielding performance of metal-based coatings,which can address the electromagnetic pollution in large-size,complex geometries,and harsh environments.In this work,oriented segregated structure with conductive networks embedded in magnetic matrix was achieved in Fe-based amorphous coatings via Ni-Cu-P functionalization of(Fe_(0.76)Si_(0.09)B_(0.1)P_(0.05))_(99)Nb_(1)amorphous powder precursors and then thermal spraying them onto aluminum(Al)substrate.Benefiting from the unique magnetic-electric structure,the coating@Al composite delivered prominent EMI shielding performance.The EMI shielding effectiveness(SE)of modified coating@Al composite is~41 dB at 8-12 GHz,doubling the value of Al substrate and is 15 dB greater than that of Ni-Cu-P-free coating@Al composite.Microstructure analysis showed that the introduced Ni−Cu−P insertions forcefully suppress the serious oxidation of the magnetic precursors during thermal spraying and form a dense conductive network in the magnetic matrix.Electron holography observation and electromagnetism simulation clarified that the modified coating can effectively trap and attenuate the incident radiations because of the electric loss from Ni−Cu−P conductive network,magnetic loss from Fe-based amorphous coating,and the electromagnetic interactions in the oriented segregated architectures.Moreover,the optimized thermal isolation and mechanical properties brought by structural improvement enable the coating to shield complex parts in thermal shock and mechanical loading environments.Our work gives an insight on the design strategies for metal-based EMI shielding materials and enriches the fundamental understanding of EMI shielding mechanisms.

Super Strong and Tough Elastomers Enabled by Sacrificial Segregated Network

The integration of high strength and toughness concurrently is a vital requirement for elastomers from the perspective of long-term durability and reliability. Unfortunately, these properties are generally conflicting in artificial materials. In the present work, we propose a facile strategy to simultaneously toughen and strengthen elastomers by constructing 3 D segregated filler network via a simple latex mixing method.The as-fabricated elastomers are featured by a microscopic 3 D interconnected segregated network of rigid graphene oxide(GO) nanosheets and a continuous soft matrix of sulfur vulcanized natural rubber(NR). We demonstrate that the interconnected segregated filler network ruptures preferentially upon deformation, and thus is more efficient in energy dissipation than the dispersed filler network. Therefore, the segregated filler network exhibits better reinforcing effects for the rubber matrix. Moreover, the excellent energy dissipating ability also contributes to the outstanding crack growth resistance through the release of concentrated stress at the crack tip. As a result, the strength, toughness and fatigue resistance of the nanocomposites are concurrently enhanced. The methodology in this work is facile and universally applicable, which may provide new insights into the design of elastomers with both extraordinary static and dynamic mechanical performance for practical applications.

Seasonal size-segregated PM10 and PAH concentrations in a rural area of sugarcane agriculture versus a coastal urban area in Southeastern Florida, USA

Airborne particulate matter （PM） is of health and environmental concern not only in highly urbanized areas, but also in rural areas that are used for intensive agricultural purposes, In this study, PM size- segregated samples were collected simultaneously for 12 months in a small town （Belle Glade, Florida）, which is the center of a vast sugarcane growing area and at Delray Beach, a coastal city in Palm Beach County, Florida. During the winter sampling period, when sugarcane foliage is burned just before harvest- ing to reduce the amount of plant matter to be handled, PM10 levels were 50% or higher than otherwise measured, indicating that sugarcane harvesting and processing is a major local source for PM10. For the rest of the year, PM10 levels at both sites are similar, suggesting that ambient PM levels at both sites are impacted by the major urban centers in Southern Florida. During late July and early August, the PM10 levels at both sites were substantially elevated and revealed the typical red-brownish color of Saharan dust. This has been reported to occur frequently with suitable meteorological conditions over the Atlantic Ocean coupled with a Sahara dust storm event. During the sugarcane harvesting season at Belle Glade, the concentrations of PAHs associated with PM10 were up to 15 times higher than those measured during the summer growing season, indicating a substantially higher exposure of the rural population to these often mutagenic and carcinogenic compounds.

Number of synchronized and segregated interior spike solutions for nonlinear coupled elliptic systems with continuous potentials

In this paper, we consider the following nonlinear coupled elliptic systems with continuous potentials:{-ε~2?u +(1 + δP(x))u = μ1 u^3+ βuv^2 in ?,-ε~2?v +(1 + δQ(x))v = μ2 v^3+ βu^2 v in ?,u > 0, v > 0 in ?,(?u)/(?v)=(?ν)/(?ν)=0on ??,(A_ε)where ? is a smooth bounded domain in R^N for N = 2, 3, δ, ε, μ_1 and μ_2 are positive parameters, β∈ R,P(x) and Q(x) are two smooth potentials defined on ?, the closure of ?. Due to Liapunov-Schmidt reduction method, we prove that(A_ε) has at least O(1/(ε| ln ε|)~N) synchronized and O(1/(ε| ln ε|)^(2 N)) segregated vector solutions for ε and δ small enough and some β∈ R. Moreover, for each m ∈(0, N) there exist synchronized and segregated vector solutions for(A_ε) with energies in the order of ε^(N-m). Our results extend the result of Lin et al.(2007) from the Lin-Ni-Takagi problem to the nonlinear Schr¨odinger elliptic systems with continuous potentials.

An Interfacial Dynamic Crosslinking Approach toward Catalyst-free and Mechanically Robust Elastomeric Vitrimer with a Segregated Structure

Elastomeric vitrimers with covalent adaptable networks are promising candidates to overcome the intrinsic drawbacks of conventional covalently-crosslinked elastomers;however, most elastomeric vitrimers show poor mechanical properties and require the addition of exogenous catalysts. Herein, we fabricate a catalyst-free and mechanically robust elastomeric vitrimer by constructing a segregated structure of sodium alginate (SA) in the continuous matrix of epoxidized natural rubber (ENR), and further crosslinking the composite by exchangeable hydroxyl ester bonds at the ENR-SA interfaces. The manufacturing process of the elastomeric vitrimer is facile and environmentally friendly without hazardous solvents or exogenous catalysts, as the abundant hydroxyl groups of the segregated SA phase can act as catalyst to activate the crosslinking reaction and promote the dynamic transesterification reaction. Interestingly, the segregated SA structure bears most of the load owing to its high modulus and small deformability, and thus ruptures preferentially upon deformation, leading to efficient energy dissipation.Moreover, the periodic stiffness fluctuation between rigid segregated SA phase and soft ENR matrix is beneficial to the crack-resisting. As a result,the elastomeric vitrimer manifests exceptional combination of catalyst-free, defect-tolerance, high tensile strength and toughness. In addition,the elastomeric vitrimer also exhibits multi-shape memory behavior which may further broaden its applications.

Simultaneously enhanced heat dissipation and tribological properties of polyphenylene sulfide-based composites via constructing segregated network structure

Self-lubricating polyphenylene sulfide(PPS)composites were fabricated by constructing a segregated network structure using the co-deposition method.Both carboxyl-functionalized multi-walled carbon nanotubes(CNTs)and silicon carbide(SiC)were successfully coated on the surface of PPS powders with the aid of self-polymerization of dopamine(PDA)and co-polymerization between PDA and polyethyleneimine(PEI),thereby forming PPS@PDA-CNTs-SiC hierarchical reinforcing hybrids.Results showed that the thermal conductivity of PPS@PDA-CNTs-SiC(0.97 W/(m K))is about 120%higher than that of PPS/CNTs/SiC.The friction coefficient(0.193)and specific wear rate(2.50×10^(-5)mm^(3)/(N m))of PPS@PDA-CNTs-SiC are 18.9%and 50%lower than those of PPS/CNTs/SiC,respectively.The enhanced thermal conductivity of PPS@PDA-CNTs-SiC contributes to rapid dissipation of frictional heat at the sliding interface which protects the polymer substrate from being destroyed or peeled,thereby improving the tribological performance.This work provides new insights into expanding the application of self-lubricating polymer composites in the fields where efficient heat dissipation is also a primary concern.

Self-assembly Behavior of Copolymers with Super Segregated Structure Containing Fluorinated Segments

Copolymers with super segregated structure of hydrophilic methoxy poly（ethylene glycol） （mPEG） and fluorophilic poly（1H,1H,2H,2H-perfluorodecyl acrylate） （PFA） were prepared. And just because of this super segregated structure which was resulted from the extremely strong incompatibility between the two blocks, several interesting self- assembly behaviors of the copolymers were displayed and studied under different conditions. Transmission electron microscope （TEM） showed that with the increase of PFA in the polymerization system, the incompatibility in this super segregated structure became stronger, and the self-assembly behavior changed from ball-like or rod-like to vesicles, and finally collapsed to sheet-like. The self-assembly behavior changed likewise when the initial concentration increased. And the interesting formation of these barrel-like and spindle-like vesicles was finally studied with different cooling speeds. It＇s finally found that with this super segregation structure, these new self-assembly morphology might be formed due to the extremely strong incompatibility between mPEG and PFA segments.

Fine-mapping and primary analysis of candidate genes associated with seed coat color in mung bean(Vigna radiata L.)

Seed coat color affects the appearance and commodity quality of mung beans(Vigna radiata L.).The substances that affect mung bean seed coat color are mainly flavonoids,which have important medicinal value.Mapping the seed coat color gene in mung beans would facilitate the development of new varieties and improve their value.In this study,an F2 mapping population consisting of 546 plants was constructed using Jilv9(black seed coat)and BIS9805(green seed coat).Using bulk segregated analysis(BSA)sequencing and kompetitive allele-specific PCR(KASP)markers,the candidate region related to seed coat color was finally narrowed to 0.66 Mb on chromosome(Chr.)4 and included eight candidate genes.Combined transcriptome and metabolome analyses showed that three of the eight candidate genes(LOC106758748,LOC106758747,and LOC106759075)were differentially expressed,which may have caused the differences in flavonoid metabolite content between Jilv9 and BIS9805.These findings can provide a research basis for cloning the genes related to seed coat color and accelerate molecular markerassisted selection breeding in mung beans.

Improving creep strength of the fine-grained heat-affected zone of novel 9Cr martensitic heat-resistant steel via modified thermo-mechanical treatment

The infamous type Ⅳ failure within the fine-grained heat-affected zone (FGHAZ) in G115 steel weldments seriously threatens the safe operation of ultra-supercritical (USC) power plants.In this work,the traditional thermo-mechanical treatment was modified via the replacement of hot-rolling with cold rolling,i.e.,normalizing,cold rolling,and tempering (NCT),which was developed to improve the creep strength of the FGHAZ in G115 steel weldments.The NCT treatment effectively promoted the dissolution of preformed M_(23)C_(6)particles and relieved the boundary segregation of C and Cr during welding thermal cycling,which accelerated the dispersed reprecipitation of M_(23)C_(6) particles within the fresh reaustenitized grains during post-weld heat treatment.In addition,the precipitation of Cu-rich phases and MX particles was promoted evidently due to the deformation-induced dislocations.As a result,the interacting actions between precipitates,dislocations,and boundaries during creep were reinforced considerably.Following this strategy,the creep rupture life of the FGHAZ in G115 steel weldments can be prolonged by 18.6%,which can further push the application of G115 steel in USC power plants.

Effect of granular shape on radial segregation in a two-dimensional drum

Granular segregation is widely observed in nature and industry.Most research has focused on segregation caused by differences in the size and density of spherical grains.However,due to the fact that grains typically have different shapes,the focus is shifting towards shape segregation.In this study,experiments are conducted by mixing cubic and spherical grains.The results indicate that spherical grains gather at the center and cubic grains are distributed around them,and the degree of segregation is low.Through experiments,a structured analysis of local regions is conducted to explain the inability to form stable segregation patterns with obviously different geometric shapes.Further,through simulations,the reasons for the central and peripheral distributions are explained by comparing velocities and the number of collisions of the grains in the flow layer.