Microstructures and mechanical properties of GH4169 alloy cylinder and its weld joints in a supercritical water reactor are studied after operating 2000 h. The results show that the GH4169 alloy cylinder exhibits good corrosion resistance under conditions of high temperature， high pressure， and sucrose mixed solution； the thickness loss rate of the cylinder is 0.005-0.255 μm/h； the corrosion products primarily consist of oxides and phosphates. However， the welded joints connecting the cylinder and other components represent a vulnerable point that significantly impacts the remaining lifespan of the reactor. The calculated crack propagation rate of the GH4169 alloy cylinder is 5.25 μm/h， indicating that it would only take 762 h for the crack to penetrate through the wall of the connector. Additionally， severe fracture occurs （the circumferential length of the crack is approximately 1/4 of the circumference） at the weld joint between cylinder and stainless-steel， resulting from the synergistic effects of galvanic corrosion， crevice corrosion， and concentrated stress. Despite these challenges， the strength loss of the cylinder is relatively small， which means that the cylinder maintains satisfactory mechanical properties.

In the aerospace field， welding serves as the primary joining process for TA3 alloy components，and the microstructure and mechanical properties of its welded joints have a significant impact on the service safety of welded components. This study compares the tensile properties of the base metal and welded specimens and studies the deformation morphology before and after tension using scanning electron microscopy combined with electron backscatter diffraction. The results show that the microstructure of TA3 alloy is equiaxed α grains before welding， and massive， acicular and serrated α grains appear after welding. The yield strength （378 MPa） and tensile strength （458 MPa） of welded specimens are higher than that of base material specimens， but the elongation is lower. The reason is that after the base meterial sample is welded， the welding temperature has the effect of aging treatment on the sample. There exists aging hardening， and the grain size inside the weld area becomes smaller， which will increase the tensile strength. Because the microhardness of the weld zone is obviously higher than that of the base metal zone， the fracture of the welded joint is located in the base meterial zone. The deformation mechanism of the weld zone is stress-induced deformation twin （\mathrm{2}\overline{\mathrm{1}}\overline{\mathrm{1}}2）［\mathrm{2}\overline{\mathrm{1}}\overline{\mathrm{1}}3］ and （\overline{\mathrm{2}}\mathrm{1}12）［\overline{\mathrm{2}}\mathrm{1}13］， with a Schmid factor of 0.038， exhibiting high shear stress and strong coordination of grain deformation. Deformation twins （\overline{\mathrm{2}}\mathrm{11}2）［\mathrm{2}\overline{\mathrm{1}}\overline{\mathrm{1}}3］ also appear in the base material region， but the Schmid factor is 0.078， indicating a relatively high degree of stress concentration.

Based on the current status and requirements of wear in zirconia ceramics， in response to the problem friction reduction performance of single-textured specimens， different texture types are combined to extract biomimetic contours from biological surfaces and design various novel composite biomimetic textures. The numerical simulation and the experimental investigation methods are used to analyze the friction reduction performance of composite biomimetic textures，solving the Reynolds equation numerically， studying the influence of composite texture types on oil film load capacity， pressure distribution area， and maximum static pressure， and conducting experimental exploration of the tribological performance using a friction and wear testing machine. The results indicate that composite biomimetic textures exhibit higher oil film load capacity， wider pressure distribution areas， and lower friction coefficients compared to other texture types， among them， the comprehensive anti-friction effect of the scale + feather composite texture is the best； the friction reduction mechanism of composite biomimetic textures can be mainly attributed to changes in contact stress points， the asymmetric distribution of pressure and abrasive storage properties， and the form of pressure distribution of composite texture is highly dependent on a single texture type.

The Fe-Ga alloy， a novel magnetostrictive material， distinguishes itself with a low driving magnetic field and remarkable magnetostrictive performance. As an alloy， it has garnered significant attention from researchers in solid-state physics and materials science due to its cost-effectiveness， superior mechanical properties， and high stability. These advantages make it particularly appealing for applications in micro-displacement devices， vibrators， and sensor technologies. The magnetostrictive characteristics of Fe-Ga alloys are influenced by various factors， including material texture orientation， magnetic domain distribution， alloying element additions， and， most importantly， the alloy’s phase structure. This paper provides an in-depth exploration of the phase structure of Fe-Ga alloy and comprehensively summarizes the impacts of various preparation methods on enhancing the preferred grain orientation 〈100〉. It further examines the effects of specific external magnetic fields and prestresses on altering the distribution of magnetic domains， as well as the influence of incorporating rare earth elements on improving magnetostrictive performance. Additionally， the article introduces recent research advancements regarding the influence of heat treatment on phase structure transformation and nanoprecipitate phase precipitation on the magnetostrictive properties of Fe-Ga alloys，contributing to advancing the understanding， promotion， and application of Fe-Ga alloy in the field of structure-function integrated precision device manufacturing.

The MnO₂ and VB₂ co-doped NiCr₂O₄ coatings（MV） with different ratios of moles are prepared by atmospheric plasma spraying（APS）， and the phase composition， microstructure， infrared emissivity and thermal shock resistance of the coatings are investigated. The results show that the co-doping of NiCr₂O₄ with MnO₂ and VB₂ can more effectively improve the infrared emissivity of the coatings than the doping of MnO₂ or VB₂， thus the coating with MnO₂ and VB₂ doping ratio of 1∶1 （MV11） has the highest emissivity. In the 0.75-2.5 μm wavelength ranges， the room temperature band emissivity of the MV11 coating is 0.928， and in the 2.5-25 μm， the infrared emissivity of the coating increases from 0.884 at room temperature to 0.918 at 1000 ℃. It is mainly attributed to the transition metal ions and B ions enter the spinel lattice， increasing the concentration of oxygen vacancy in the lattice， introducing partial energy levels into the bandgap， and causing lattice distortions， enhancing free carrier transition absorption and infrared lattice vibration absorption. In addition， after 30 thermal cycles of water cooling at 25-750 ℃， microcracks appear in the coating， but the phase structure did not change significantly， and the emissivity decreases slightly， indicating that the coating has good thermal shock resistance.

This study utilizes mushroom stalks as a biological template and melamine as a precursor for carbon nitride to synthesize g-C₃N₄/C，via thermal polymerization method. Copper sulfate pentahydrate （CuSO₄·5H₂O），ammonium molybdate tetrahydrate （（NH₄）₆Mo₇O₂₄·4H₂O），and thiourea （CH₄N₂S） are selected as the sources for Cu，Mo，and S，respectively. A two-step hydrothermal process is employed to prepare CuS/MoS₂ composites with different mass ratios. Then CuS/MoS₂ is anchored on the surface of g-C₃N₄/C to obtain CuS/MoS₂-g-C₃N₄/C composite electrode materials. The composite electrode materials are characterized by their phase structure，microstructure，pore structure，and capacitance performance. The results indicate that the CuS/MoS₂-g-C₃N₄/C composite electrode materials exhibit high purity，good crystallinity，good phase contact interface， and abundant porous structure. In electrochemical performance testing，the CuS/MoS₂ composite material with a mass ratio of MoS₂ to CuS at 1∶2 demonstrates optimal electrochemical performance，achieving a specific capacitance of 230 F·g^-1 at a current density of 1 A·g^-1. When the mass ratio of CuS/MoS₂ to g-C₃N₄/C is 1∶1，the CuS/MoS₂-g-C₃N₄/C composite material exhibits the best electrochemical performance，with a specific capacitance of 434.7 F·g^-1. Moreover，after 1000 cycles，the capacitance retention rate is 89.2%，showing good stability.

The β titanium alloy Ti-1300 is fabricated utilizing laser engineered net shaping （LENS） technology. This study systematically examine the microstructural evolution of the alloy along the deposition direction during the LENS process， and elucidate the intrinsic relationship between its mechanical properties and microstructure. The results indicate that the thermal cycling of each deposited layer in the LENS process has a profound impact on the microstructural evolution. Initially， columnar crystals are formed with a thickness of （15.6±1.2） mm， comprising approximately 20% of the total deposited thickness. Subsequently， these grains transform into equiaxed grains. Within the as-deposited grains， the microstructure undergo a transition from a basket-weave structure to a lamellar structure， and the discontinuous grain boundary α phase changes to a continuous grain boundary α phase along the deposition direction. Notably， the basket-weave microstructure imparts exceptional strength to the alloy. However， the continuous grain boundary α phase tends to promote intergranular fracture， resulting in reduced ductility.

Welding of cryogenic 9Ni steel is performed using NiCrMo alloy systems with different Nb and C contents. The microstructure and mechanical properties of the welded joints are investigated， and the fracture toughness of the joints under ultra-cryogenic conditions is analyzed by crack tip opening displacement （CTOD） tests. The results show that the welded joint exhibits distinct zoning characteristics. The nickel-based weld metal primarily consists of an austenitic columnar crystal matrix and secondary phases. The secondary phases include fine nanoscale banded precipitates and Nb-rich solidification phases formed in the final stage of weld pool solidification. The precipitates are mainly composed of metal carbides （MC） and Laves phases. With the increase of Nb and C content， the number and average particle size of secondary phases in the nickel-based alloy increase， leading to an improved tensile strength of the joint， but reduced cryogenic impact toughness and fracture toughness. The load-notch opening displacement （F-V） curves show that the characteristic load F_m of the joint first increases and then decreases with the addition of Nb and C， while the corresponding characteristic plastic displacement value V_p decreases monotonically with the increase of secondary phases. The fracture surface of the CTOD specimens shows the same zoning characteristics. As the Nb and C content increases， the width of the stable crack propagation region on the fracture surface gradually decreases， indicating a deterioration in the fracture toughness of the weld.

Spectral computed tomography （spectral CT） is an emerging detection technology that acquires more comprehensive tissue composition information by measuring an object’s absorption of X-rays of different energies. It plays a pivotal role in various fields such as medical diagnosis， non-destructive testing， material analysis， and security monitoring. Material decomposition algorithms are the core of spectral CT technology， aiming to decompose the composition information of different tissues from multi-energy data. These algorithms are crucial for enhancing the quality and accuracy of decomposed images. This paper reviews the data acquisition methods and mathematical models for material decomposition in spectral CT. It focuses on discussing the research progress of spectral CT material decomposition algorithms in four aspects： projection domain， image domain， direct iteration， and deep learning-based methods. It conducts an in-depth comparative analysis of the theoretical advantages， technical limitations， and current application status of various algorithms. The paper points out that the future research trends in this field include hybrid decomposition optimization in the projection domain， fusion prior constraints and multi-model data in the image domain， convergence stability improvements in direct iteration， and transferability and high generalization in deep learning.

Carbon fiber reinforced thermoplastic composites（CFRTP） have superior comprehensive mechanical property，as well as rapid prototyping，weldability and recyclability.The application of CFRTP are gradually increasing in aerospace，vehicle manufacturing and other fields.Ultrasonic welding is recognized as one of the most suitable methods for CFRTP.With the increase of the application of CFRTP in aerospace main load-bearing structures，the discrete solder joints in the form of traditional ultrasonic spot welding are difficult to meet the requirement of the strength of them.Accordingly，foreign scholars have proposed ultrasonic continuous welding technology to realize the seam welding connection of CFRTP structures，which has not been reported in domestic literature.In this paper，the research results of CFRTP ultrasonic continuous welding are reviewed from four aspects：CFRTP ultrasonic continuous welding equipment，joint design，process characteristics and quality inspection.The scientific problems and technical bottlenecks to be solved in CFRTP ultrasonic continuous welding are discussed，so as to provide a reference for the development of CFRTP ultrasonic continuous welding technology of our country.