High-temperature resistant polymer nanocomposites with exfoliated organic-modified montmorillonite nanosheets strongly adsorbed on polymer chains

It has been demonstrated that almost all polymer-clay nanocomposites show higher temperature stability than that of pure polymer, which is attributed to the active exfoliated clay nanosheet firmly adsorbed onto the polymer chains, due to polerization and nucleation effect, the clay nanosheets could protect the polymer chains from destroying. To prove such mechanism, the water-soluble polymer nanocomposites(AAA/SLS-MMT) were synthesized by the in-situ polymerization of 2-acrylamide-2-methyl-propane sulfonic acid, acrylamide, 4-acryloylmorpholine, and organically modified montmorillonite. The techniques of nuclear magnetic resonance, atomic force microscopy and scanning electron microscopy etc., clearly characterized the successful synthesized of sample's structure, the exfoliated MMT nanosheet adsorbed polymer chain's scale, and well-dispersed morphology, espectively. The adsorption model, X-ray photoelectron spectroscopy presented the existence of strong adsorption, while molecular simulation calculations first concluded that the strong adsorption energy was-13032.06 kcal/mol. Thermo-gravimetric-analysis proved the temperature of maximum thermal degradation of powder sample(AAA/1.0 wt% SLS-MMT) was over 298℃. After ageing at 180℃ for 4 h, the apparent viscosity of 5 g/L AAA/1.0 wt% SLS-MMT aqueous solution was 326.7 mPa,s, while that of pure polymer(AAA) was only 8.3 mPa,s. This optimized sample has the smallest FLAPIvalue at all test temperatures from 180 to 220℃ in both fresh and salt water based drilling fluid. All the evidences of high temperature resistance indicate that the strong adsorption can enhance the thickness of hydrated shell and adsorption of clay particles in drilling fluid at high temperature. Such mechanism supplied the better way to design high-temperature resistant fluid loss additives for deep and ultra-deep oil and gas formation engineering.

A Novel Fracturing Fluid with High-Temperature Resistance for Ultra-Deep Reservoirs

Ultra-deep reservoirs play an important role at present in fossil energy exploitation.Due to the related high temperature,high pressure,and high formation fracture pressure,however,methods for oil well stimulation do not produce satisfactory results when conventional fracturing fluids with a low pumping rate are used.In response to the above problem,a fracturing fluid with a density of 1.2~1.4 g/cm^(3)was developed by using Potassium formatted,hydroxypropyl guanidine gum and zirconium crosslinking agents.The fracturing fluid was tested and its ability to maintain a viscosity of 100 mPa.s over more than 60 min was verified under a shear rate of 1701/s and at a temperature of 175℃.This fluid has good sand-carrying performances,a low viscosity after breaking the rubber,and the residue content is less than 200 mg/L.Compared with ordinary reconstruction fluid,it can increase the density by 30%~40%and reduce the wellhead pressure of 8000 m level reconstruction wells.Moreover,the new fracturing fluid can significantly mitigate safety risks.

Performance Assessment on Corrosion Resistance of Refractory Materials Based on High-temperature Machine Vision Technology

Refractory materials,as the crucial foundational materials in high-temperature industrial processes such as metallurgy and construction,are inevitably subjected to corrosion and penetration from high-temperature media during their service.Traditionally,observing the in-situ degradation process of refractory materials in complex high-temperature environments has presented challenges.Post-corrosion analysis are commonly employed to assess the slag resistance of refractory materials and understand the corrosion mechanisms.However,these methods often lack information on the process under the conditions of thermal-chemical-mechanical coupling,leading to potential biases in the analysis results.In this work,we developed a non-contact high-temperature machine vision technology by the integrating Digital Image Correlation(DIC)with a high-temperature visualization system to explore the corrosion behavior of Al2O3-SiO2 refractories against molten glass and Al2O3-MgO dry ramming refractories against molten slag at different temperatures.This technology enables realtime monitoring of the 2D or 3D overall strain and average strain curves of the refractory materials and provides continuous feedback on the progressive corrosion of the materials under the coupling conditions of thermal,chemical,and mechanical factors.Therefore,it is an innovative approach for evaluating the service behavior and performance of refractory materials,and is expected to promote the digitization and intelligence of the refractory industry,contributing to the optimization and upgrading of product performance.

Effect of La_2O_3/Ce O_2 particle size on high-temperature oxidation resistance of electrodeposited Ni-La_2O_3/Ce O_2 composites

Ni-La2O3/CeO2 composite films were prepared by electrodeposition from a nickel sulfate bath containing certain content of micrometer and nanometer La2O3/CeO2 particles. The effect of La2O3 or CeO2 particle size on the oxidation resistance of the electrodeposited Ni-La2O3/CeO2 composites in air at 1000 °C was studied. The results indicate that, compared with the electrodeposited Ni-film, Ni-La2O3/CeO2 composites exhibit a superior oxidation resistance due to the codeposited La2O3 or CeO2 particles blocking the outward diffusion of nickel. Moreover, compared with nanoparticles, La2O3 or CeO2 microparticles have stronger effect because La2O3 or CeO2 microparticles also act as a diffusion barrier layer at the onset of oxidation.

Harness High-Temperature Thermal Energy via Elastic Thermoelectric Aerogels

Despite notable progress in thermoelectric(TE)materials and devices,developing TE aerogels with high-temperature resistance,superior TE performance and excellent elasticity to enable self-powered high-temperature monitoring/warning in industrial and wearable applications remains a great challenge.Herein,a highly elastic,flame-retardant and high-temperature-resistant TE aerogel,made of poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate)/single-walled carbon nanotube(PEDOT:PSS/SWCNT)composites,has been fabricated,displaying attractive compression-induced power factor enhancement.The as-fabricated sensors with the aerogel can achieve accurately pressure stimuli detection and wide temperature range monitoring.Subsequently,a flexible TE generator is assembled,consisting of 25 aerogels connected in series,capable of delivering a maximum output power of 400μW when subjected to a temperature difference of 300 K.This demonstrates its outstanding high-temperature heat harvesting capability and promising application prospects for real-time temperature monitoring on industrial high-temperature pipelines.Moreover,the designed self-powered wearable sensing glove can realize precise wide-range temperature detection,high-temperature warning and accurate recognition of human hand gestures.The aerogel-based intelligent wearable sensing system developed for firefighters demonstrates the desired self-powered and highly sensitive high-temperature fire warning capability.Benefitting from these desirable properties,the elastic and high-temperature-resistant aerogels present various promising applications including self-powered high-temperature monitoring,industrial overheat warning,waste heat energy recycling and even wearable healthcare.

Enhanced High-Temperature Energy Storage Performance of All-Organic Composite Dielectric via Constructing Fiber-Re in forced Structure

Optimizing the high-temperature energy storage characteristics of energy storage dielectrics is of great significance for the development of pulsed power devices and power control systems.Selecting a polymer with a higher glass transition temperature(T_(g))as the matrix is one of the effective ways to increase the upper limit of the polymer operating temperature.However,current high-T_(g)polymers have limitations,and it is difficult to meet the demand for high-temperature energy storage dielectrics with only one polymer.For example,polyetherimide has high-energy storage efficiency,but low breakdown strength at high temperatures.Polyimide has high corona resistance,but low high-temperature energy storage efficiency.In this work,combining the advantages of two polymer,a novel high-T_(g)polymer fiber-reinforced microstructure is designed.Polyimide is designed as extremely fine fibers distributed in the composite dielectric,which will facilitate the reduction of high-temperature conductivity loss for polyimide.At the same time,due to the high-temperature resistance and corona resistance of polyimide,the high-temperature breakdown strength of the composite dielectric is enhanced.After the polyimide content with the best high-temperature energy storage characteristics is determined,molecular semiconductors(ITIC)are blended into the polyimide fibers to further improve the high-temperature efficiency.Ultimately,excellent high-temperature energy storage properties are obtained.The 0.25 vol%ITIC-polyimide/polyetherimide composite exhibits high-energy density and high discharge efficiency at 150℃(2.9 J cm^(-3),90%)and 180℃(2.16 J cm^(-3),90%).This work provides a scalable design idea for high-performance all-organic high-temperature energy storage dielectrics.

High-temperature Resistance Performance of An Inorganic Adhesive for Concrete Structures Strengthened with CFRP Sheets

Organic epoxy matrices have been widely used in the FRP reinforcing technique, but they have serious disadvantages of poor high-temperature resistance. An inorganic adhesive is invented to replace the organic adhesive. For the inorganic adhesive at normal temperature and different high temperatures, the microstructure and phase composition are investigated by means of X-ray diffraction （XRD） and SEM respectively. Results show that inorganic adhesive can resist at least 600 ℃ high temperature. Fire-resistance performance of inorganic adhesive can meet the requirements of fiber reinforced polymer （FRP） strengthened RC structures.

TiN/Fe_(2)N/C composite with stable and broadband high-temperature microwave absorption

Facing the complex variable high-temperature environment,electromagnetic wave(EMW)absorbing materials maintaining high stability and satisfying absorbing properties is essential.This study focused on the synthesis and EMW absorbing performance evaluation of TiN/Fe_(2)N/C composite materials,which were prepared using electrostatic spinning followed by a high-temperature nitridation process.The TiN/Fe_(2)N/C fibers constructed a well-developed conductive network that generates considerable conduction loss.The heterogeneous interfaces between different components generated a significant level of interfacial polarization.Thanks to the synergistic effect of stable dielectric loss and optimized impedance matching,the TiN/Fe_(2)N/C composite materials demonstrated excellent and stable absorption performance across a wide temperature range(293-453 K).Moreover,TiN/Fe_(2)N/C-15 achieved a minimum reflection loss(RL)of−48.01 dB and an effective absorption bandwidth(EAB)of 3.64 GHz at 2.1 mm and 373 K.This work provides new insights into the development of high-efficiency and stabile EMW absorbing materials under complex variable high-temperature conditions.

Genetics and Molecular Mapping of a High-Temperature Resistance Gene to Stripe Rust in Seeding-Stage in Winter Wheat Cultivar Lantian 1

Stripe rust, caused by Puccinia striiformis Westend. f. sp. tritici （Pst）, is a severe foliar disease of common wheat （Triticum aestivum L.） in the world. Resistance is the best approach to control the disease. The winter wheat cultivar Lantian 1 has high-temperature resistance to stripe rust. To determing the gene（s） for the stripe rust resistance, Lantian 1 was crossed with Mingxian 169 （M169）. Seedlings of the parents, and F 1 , F 2 and F 2-3 progenies were tested with races CYR32 of Pst under controlled greenhouse conditions. Lantian 1 has a single partially dominant gene conferred resistance to race CYR32, designated as YrLT1. Simple sequence repeat （SSR） techniques were used to identify molecular markers linked to YrLT1. A linkage group of five SSR markers was constructed for YrLT1 using 166 F 2 plants. Based on the SSR marker consensus map and the position on wheat chromosome, the resistance gene was assigned on chromosome 2DL. Amplification of a set of nulli-tetrasomic Chinese Spring lines with SSR marker Xwmc797 confirmed that the resistance gene was located on the long arm of chromosome 2D. Because of its chromosomal location and the high-temperature resistance, this gene is different from previously described genes. The molecular map spanned 29.9 cM, and the genetic distance of two close markers Xbarc228 and Xcfd16 to resistance gene locus was 4.0 and 5.7 cM, respectively. The polymorphism rates of the flanking markers in 46 wheat lines were 2.1 and 2.1%, respectively; and the two markers in combination could distinguish the alleles at the resistance locus in 97.9% of tested genotypes. This new gene and flanking markers should be useful in developing wheat cultivars with high level and possible durable resistance to stripe rust.

Flexural behavior of composite beams after the ultimate limit state externally strengthened with CFRP sheets bonded with high-temperature resistant matrix

In this paper the alkali-activated slag cementitious materials(AASCM)which strength at 600 ℃ is larger than that of AASCM at room temperature,were prepared to paste CFRP sheets to strengthen four simply supported unbonded prestressed composite beams encased circular steel tube truss after ultimate limit state.Test on flexural behavior of these four beams was performed.Moreover,normal section load-bearing capacity of these beams and the curve load-deflection at mid-span were obtained.Experimental results show that it is feasible to strengthen concrete members with CFRP sheets bonded with AASCM.Based on the experimental results and theoretical study,computational method of stiffness is proposed for calculating bending rigidity and normal section load-bearing capacity of concrete simply supported beams strengthened with CFRP sheets bonded with AASCM.Formula of bending rigidity calculation was founded which results are in good agreement with testing data.

A high-temperature resistant and high-density polymeric saturated brine-based drilling fluid

Three high-temperature resistant polymeric additives for water-based drilling fluids are designed and developed:weakly cross-linked zwitterionic polymer fluid loss reducer(WCZ),flexible polymer microsphere nano-plugging agent(FPM)and comb-structure polymeric lubricant(CSP).A high-temperature resistant and high-density polymeric saturated brine-based drilling fluid was developed for deep drilling.The WCZ has a good anti-polyelectrolyte effect and exhibits the API fluid loss less than 8 mL after aging in saturated salt environment at 200°C.The FPM can reduce the fluid loss by improving the quality of the mud cake and has a good plugging effect on nano-scale pores/fractures.The CSP,with a weight average molecular weight of 4804,has multiple polar adsorption sites and exhibits excellent lubricating performance under high temperature and high salt conditions.The developed drilling fluid system with a density of 2.0 g/cm^(3)has good rheological properties.It shows a fluid loss less than 15 mL at 200°C and high pressure,a sedimentation factor(SF)smaller than 0.52 after standing at high temperature for 5 d,and a rolling recovery of hydratable drill cuttings similar to oil-based drilling fluid.Besides,it has good plugging and lubricating performance.

Review Article: High-Temperature Adult-Plant Resistance, Key for Sustainable Control of Stripe Rust

High-temperature adult-plant (HTAP) resistance expresses when plants grow old and the weather becomes warm. This non-race specific and durable type of resistance has been used successfully in control of wheat stripe rust in the US since early 1960s. This article describes practical procedures for identification and characterization of HTAP resistance and reviews recent studies on discovery of genes conferring HTAP resistance. Recent studies providing insights to the molecular basis for the durability of HTAP resistance will be presented. Strategies for improving levels of HTAP resistance and improving control of stripe rust through combining HTAP resistance with effective all-stage resistance will be discussed.

Micro-analysis of high-temperature oxidation-resistance of a new kind of heat-resistant grid plate in grate-kiln

To further improve the oxidation-resistance of materials and reduce the cost of grid plates in grate-kiln, a new kind of heat-resistant grid plate was developed. The microstructure of this grid plate with a life more than 18 months was studied by XRD, SEM and EDS techniques. The results show that high hardness, high intensity and good impact property make the new kind of heat-resistant grid plate and its oxide film have a higher resistance to deformation and abrasion at 900-1000℃ Besides, small grain size is beneficial to form a complete protective oxide film. The oxide film composed of SiO2 layer, Cr2O3 layer and Fe2O3 layer is rather thin and bonds closely with the backing. The forming of the chemical stable nickel-rich layer increases the density of Cr2O3 layer.

Pathogenesis-related protein genes involved in race-specific allstage resistance and non-race specific high-temperature adultplant resistance to Puccinia striiformis f. sp. tritici in wheat

Interactions of the stripe rust pathogen （Puccinia striiformis f. sp responses. Among various genes involved in the plant-pathogen related （PR） protein genes determine different defense responses tritici） with wheat plants activate a w^ae range OT nost nteractions, the expressions of particular pathogenesis-Different types of resistance have been recognized and utilized for developing wheat cultivars for resistance to stripe rust. All-stage resistance can be detected in seedling stage and remains at high levels throughout the plant growth stages. This type of resistance is race-specific and not durable. In contrast, plants with only high-temperature adult-plant （HTAP） resistance are susceptible in seedling stage, but become resistant when plants grow older and the weather becomes warmer. HTAP resistance controlled by a single gene is partial, but usually non-race specific and durable. The objective of this study was to analyze the expression of PR protein genes involved in different types of wheat resistance to stripe rust. The expression levels of 8 PR protein genes （PR1, PRI.2, PR2, PR3, PR4, PR5, PR9 and PRIO） were quantitatively evaluated at 0, 1, 2, 7 and 14 days after inoculation in single resistance gene lines of wheat with all-stage resistance genes YrTrl, Yr76, YrSP and YrExp2 and lines carrying HTAP resistance genes Yr52, Yr59, Yr62 and Yr7B. Races PSTv-4 and PSTv-37 for compatible and incompatible interactions were used in evaluation of PR protein gene expression in wheat lines carrying all-stage resistance genes in the seedling- stage experiment while PSTv-37 was used in the HTAP experiment. Analysis of quantitative real-time polymerase chain reaction （qRT-PCR） revealed that all of the PR protein genes were involved in the different types of resistance controlled by different Yr genes. However, these genes were upregulated at different time points and at different levels during the infection process among the wheat lines with different Yr genes for either all-stage resistance or HTAP resistance. Some of the genes were also induced in compatible interactions, but the levels were almost always higher in the incompatible interaction than in the compatible interaction at the same time point for each Yr gene. These results indicate that both salicylic acid and jasmonate signaling pathways are involved in both race-specific all-stage resistance and non-race specific HTAP resistance. Although expressing at different stages of infection and at different levels, these PR protein genes work in concert for contribution to different types of resistance controlled by different Yr genes.

Enhanced thermal stability and mechanical properties of high-temperature resistant Al-Cu alloy with Zr and Mn micro-alloying

The high temperature(HT)thermal stability and mechanical properties of Al-5%Cu(AC)and Al-5%Cu-0.2%Mn-0.2 Zr%(ACMZ)alloys from 573 to 673 K were systematically studied.The results displayed that micro-alloying additions of Zr and Mn elements have presented a significant role in stabilizing the main strengthening metastableθ′precipitates at a temperature as high as 573 K.Simultaneously,the HT tensile test demonstrated that ACMZ alloy retained their strength of(88.6±8.8)MPa,which was much higher than that of AC alloy((32.5±0.8)MPa)after the thermal exposure at 573 K for 200 h.Finally,the underlying mechanisms of strength and ductility enhancement mechanism of the ACMZ alloy at HT were discussed in detail.

Effect of RE addition on solidification process and high-temperature strength of Al-12%Si-4%Cu-1.6%Mn heat-resistant alloy

The effect of RE addition on solidification process and high-temperature strength of Al-12%Si-4%Cu-1.6%Mn(in wt.%)heat-resistant alloy was investigated by microstructure observation and tensile test.A great number of fine needle-like RE-rich phases are observed in the alloys with RE addition. Solutionizing treatment does not change their morphologies and sizes, indicating that they have good thermal stability. The addition of RE totally alters the solidification process of eutectic CruAl2 phase, from network-like phase in the form of segregation at the final eutectic grain boundaries to discretely blocky phase growing on the hair-filamentous RE-rich needles. In the alloys with Ce addition, blocky CuAl2, particulate Al15Mn3Si2 and needle-like RE-rich needle phases grow together, but they did not occur in the alloy with only La addition. The addition of RE does not considerably improve the strength of the alloy at high temperatures. The formation of RE-rich phases also does not significantly alter the originating and propagating of micro-cracks in the alloy during tensile test.

Different variation behaviors of resistivity for high-temperature-grown and low-temperature-grown p-GaN films

Two series of p-GaN films grown at different temperatures are obtained by metal organic chemical vapor deposition（MOCVD）. And the different variation behaviors of resistivity with growth condition for high- temperature（HT）-grown and low-temperature（LT）-grown p-GaN films are investigated. It is found that the resistivity of HT-grown p-GaN film is nearly unchanged when the NH_3 flow rate or reactor pressure increases. However, it decreases largely for LT-grown p-GaN film.These different variations may be attributed to the fact that carbon impurities are easy to incorporate into p-GaN film when the growth temperature is low. It results in a relatively high carbon concentration in LT-grown p-GaN film compared with HT-grown one. Therefore, carbon concentration is more sensitive to the growth condition in these samples, ultimately,leading to the different variation behaviors of resistivity for HT- and LT-grown ones.

High-temperature oxidation behavior of heat resistant stainless steel 1.4828

The kinetic curves of the high-temperature oxidation of austenitic heat resistant stainless steel 1. 4828 at 1 050 ℃ were measured using a weighing method. It is shown that the oxidation curves at 1 050 ℃ followed the parabolic line law, and after 250 h of oxidation, the mass gain was about 80 g/m2. The surface morphology and structure of the oxide layers were studied by scanning electron microscopy and X-ray diffraction. A complicated oxide layer obtained at 1 050 ℃ was mainly composed, from inner to outer, of （FeSi） 3 04, Cr2 03, Fe2 03, and spinel oxides FeCr204 and NiMn204.

HZSM-5 zeolites undergoing the high-temperature process for boosting the bimolecular reaction in n-heptane catalytic cracking

High-temperature treatment is key to the preparation of zeolite catalysts.Herein,the effects of hightemperature treatment on the property and performance of HZSM-5 zeolites were studied in this work.X-Ray diffraction,N2physisorption,27Al magic angle spinning nuclear magnetic resonance(MAS NMR),and temperature-programmed desorption of ammonia results indicated that the hightemperature treatment at 650℃ hardly affected the inherent crystal and texture of HZSM-5zeolites but facilitated the conversion of framework Al to extra-framework Al,reducing the acid site and enhancing the acid strength.Moreover,the high-temperature treatment improved the performance of HZSM-5 zeolites in n-heptane catalytic cracking,promoting the conversion and light olefins yield while inhibiting coke formation.Based on the kinetic and mechanism analysis,the improvement of HZSM-5 performance caused by high-temperature treatment has been attributed to the formation of extra-framework Al,which enhanced the acid strength,facilitated the bimolecular reaction,and promoted the entropy change to overcome a higher energy barrier in n-heptane catalytic cracking.

Synergistic effect of Zr and Mo on precipitation and high-temperature properties of Al-Si-Cu-Mg alloys

This study focuses on finding a solution to the sharp decline in mechanical properties of Al-Si-Cu-Mg alloys due to rapid coarsening of traditional intermediate phases at high temperature.A new type of modified al oy,to be used in automobile engines at high temperatures,was prepared by adding Zr and Mo into Al-Si-Cu-Mg alloy.The synergistic effects of Zr and Mo on the microstructure evolution and high-temperature mechanical properties were studied.Results show that the addition of Zr and Mo generates a series of intermetallic phases dispersed in the alloy.They can improve the strength of the alloy by hindering dislocation movement and crack propagation.In addition,some nano-strengthened phases show coherent interfaces with the matrix and improve grain refinement.The addition of Mo greatly improves the heat resistance of the alloy.The extremely low diffusivity of Mo enables it to improve the thermal stability of the intermetallic phases,inhibit precipitation during aging,reduce the size of the precipitates,and improve the heat resistance of the alloy.