Synthesis of Neodymium-Doped Yttrium Aluminum Garnet (Nd∶YAG) Nano-Sized Powders by Low Temperature Combustion

The homogeneously dispersed, less agglomerated (Nd0.01Y0.99)3Al5O12 nano-sized powders were synthesized by the low temperature combustion (LCS), using Nd2O3, Y2O3, Al(NO3)3·9H2O, ammonia water and citric acid as starting materials. This method effectively solves the problems caused by solid-state reaction at high temperature and hard agglomerates brought by the chemical precipitation method. The powders were characterized by TG-DTA, XRD, FT-IR, TEM respectively and the photoluminescence (PL) spectra of (Nd0.01Y0.99)3Al5O12 green and sintered ceramic disks were measured. The results show that the forming temperature of YAG crystal phase is 850 ℃ and YAP crystal phase appearing during the calcinations transforms to pure YAG at 1050 ℃. The particle size of the powders synthesized by the LCS is in a range of 20～50 nm depending on the thermal treatment temperatures. The effectively induced cross section (σin) with the value 4.03×10-19 cm2 of (Nd0.01Y0.99)3Al5O12 ceramics is about 44% higher than that of single crystal.

Characterization, preparation, and reuse of metallic powders for laser powder bed fusion: a review

Laser powder bed fusion(L-PBF) has attracted significant attention in both the industry and academic fields since its inception, providing unprecedented advantages to fabricate complex-shaped metallic components. The printing quality and performance of L-PBF alloys are infuenced by numerous variables consisting of feedstock powders, manufacturing process,and post-treatment. As the starting materials, metallic powders play a critical role in infuencing the fabrication cost, printing consistency, and properties. Given their deterministic roles, the present review aims to retrospect the recent progress on metallic powders for L-PBF including characterization, preparation, and reuse. The powder characterization mainly serves for printing consistency while powder preparation and reuse are introduced to reduce the fabrication costs.Various powder characterization and preparation methods are presented in the beginning by analyzing the measurement principles, advantages, and limitations. Subsequently, the effect of powder reuse on the powder characteristics and mechanical performance of L-PBF parts is analyzed, focusing on steels, nickel-based superalloys, titanium and titanium alloys, and aluminum alloys. The evolution trends of powders and L-PBF parts vary depending on specific alloy systems, which makes the proposal of a unified reuse protocol infeasible. Finally,perspectives are presented to cater to the increased applications of L-PBF technologies for future investigations. The present state-of-the-art work can pave the way for the broad industrial applications of L-PBF by enhancing printing consistency and reducing the total costs from the perspective of powders.

Effect of surfactants on dispersion property and morphology of nano-sized nickel powders

Fine face-centered cubic (FCC) nickel powders were synthesized by liquid phase reduction with different surfactants. The products were investigated by scanning electron microscopy (SEM), laser particle size analyzer and X-ray powder diffraction (XRD). The results indicate that the type, dosage and relative molecular mass of surfactants significantly impact the purity, dispersion property, particle size, size distribution and morphology of the products. The nonionic surfactants poly ethylene glycol (PEG) and polyethylene glycol sorbitan monostearate (Tween) showed better dispersing ability in the reaction system than the others. The optimal mass ratios of surfactant to Ni are 100 mg/g and 150 mg/g for PEG-600 and Tween-40, respectively. The products obtained in the optimal conditions have ideal morphology and narrow size distribution. Moreover, study on the relative molecular mass effect revealed that with the increase of the relative molecular mass of Tween, the morphology of nickel powders changed from sphere to spiny ball.

Fabrication and characterization of multi-scale coated boron powders with improved combustion performance:A brief review

Boron has high mass and volume calorific values,but it is difficult to ignite and has low combustion efficiency.This literature review summarizes the strategies that are used to solve the above-mentioned problems,which include coatings of boron by using fluoride compounds,energetic composites,metal fuels,and metal oxides.Coating techniques include recrystallization,dual-solvent,phase transfer,electrospinning,etc.As one of the effective coating agents,the fluorine compounds can react with the oxide shell of boron powder.In comparison,the energetic composites can effectively improve the flame temperature of boron powder and enhance the evaporation efficiency of oxide film as a condensed product.Metals and metal oxides would react with boron powder to form metal borides with a lower ignition point,which could reduce its ignition temperature.

Fabrication of Fine-Grained Si_3N_4-Si_2N_2O Composites by Sintering Amorphous Nano-sized Silicon Nitride Powders

Si3N4-Si2N2O composites were fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering （ LPS ）. The Si2 N2O phase was generated by an in-situ reaction 2 Si3 N4 （ s ） ＋ 1.5 02 （ g ） = 3 Si2 N2O （ s ） ＋ N2 （ g ） . The content of Si2 N2 O phase up to 60% in the volume was obtained at a sintering temperature of 1 650℃ and reduced when the sintering temperature increased or decreased, indicating the reaction is reversible. The mass loss, relative density and average grain size increased with increasing the sintering temperature. The average grain size was less than 500 nm when the sintering temperature was below 1 700 ℃. The sintering procedure contains a complex crystallization and a phase transition ： amorphous silicon nitride→equiaxial α- Si3 N4→ equiaxial β- Si3 N4→ rod- like Si2 N2O→ needle- like β- Si3N4 . Small round-shaped β→ Si3 N4 particles were entrapped in the Si2 N2O grains and a high density of staking faults was situated in the middle of Si2 N2O grains at a sintering temperature of 1 650 ℃. The toughness inereased from 3.5 MPa·m^1/2 at 1 600 ℃ to 7.2 MPa· m^1/2 at 1 800 ℃ . The hardness was as high as 21.5 GPa （Vickers） at 1 600 ℃ .

Preparation of Nano-sized Zirconium Carbide Powders through a Novel Active Dilution Self-propagating High Temperature Synthesis Method

High quality nano-sized zirconium carbide （ZrC） powders were successfully fabricated via a developed chemical active dilution self-propagating high-temperature synthesis （SHS） method assisted by ball milling pretreatment process using traditional cheap zirconium dioxide powder （ZrO2）, magnesium powder （Mg） and sucrose （C12H22Oll） as raw materials. FSEM, TEM, HRTEM, SAED, XRD, FTIR and Raman, ICP- AES, laser particle size analyzer, oxygen and nitrogen analyzer, carbon/sulfur determinator and TG-DSC were employed for the characterization of the morphology, structure, chemical composition and thermal stability of the as-synthesized ZrC samples. The as-synthesized samples demonstrated high purity, low oxygen content and evenly distributed ZrC nano-powders with an average particle size of 50nm. In addition, the effects of endothermic rate and the possible chemical reaction mechanism were also discussed.

Corrosion resistance of waterborne epoxy coating pigmented by nano-sized aluminium powder on steel

A novel kind of waterborne epoxy coating pigmented by nano-sized aluminium powders on high strength steel was formulated. Several coatings with different pigment volume content (PVC) were prepared. The coating morphology was observed using scanning electron microscopy (SEM), and the electrochemical properties were investigated by electrochemical impedance spectroscopy (EIS). Immersion test and neutral salt spray test were also conducted to investigate the corrosion resistance of the coating. It is demonstrated that the critical pigment volume content (CPVC) value is between 30% and 40%. The coating with PVC of 30% exhibits good corrosion resistance in 3.5% (mass fraction) NaCl solution.

Synthesis and Characterization of Nano-sized Boron Powder Prepared by Plasma Torch

Hydrogen thermal plasma jet was employed to prepare nano-sized boron powder with hydrogen reduction of BCI3. The maximum yield of nano-sized boron powders was about 50% with the operational conditions of H2/BCl3 of 4.5：1, total feed of 4.9 m3/h, and plasma power of 25 kW. The samples were analyzed by X-ray diffraction （XRD）, field emission scanning electron microscopy （FE-SEM）, and inductively coupled plasma - mass spectrometry （ICP-MS）, inductively coupled plasma - atomic emission spectrometry （ICP-AES）, inductive combustion infrared absorption （ICIA） and infrared thermal conductivity of oxygen and nitrogen analyzer （ITCA）. The results show that the boron powders have different crystal structures with higher dispersion and purity. The average diameter is about 50 nm, and the purity is 90.29% or so. This new technology can use simple process to produce high quality boron powders, and is feasible for industrial production.

The effects of dietary supplementation with mushroom or selenium enriched mushroom powders on the growth performance and intestinal health of post-weaned pigs

Background There is an urgent need to identify natural bioactive compounds that can enhance gastrointestinal health and promote pig growth performance in the absence of pharmacological levels of zinc oxide(ZnO).The objectives of this study were to:1)compare the effects of mushroom powder supplemented with inorganic selenium(inSeMP)to mushroom powder enriched with organic selenium(orgSeMP)to pharmacological levels of ZnO on growth performance and faecal scores(FS)for the first 21 d post-weaning(Period 1);and 2)compare the molecular and microbial effects of inSeMP and orgSeMP in these pigs on d 39 post-weaning(Period 2).Methods In Period 1,pigs(3 pigs/pen;8 pens/treatment)were assigned to:(1)basal diet(control);(2)basal diet+zinc oxide(ZnO)(3100 mg/kg d 1–14,1550 mg/kg d 15–21);(3)basal diet+mushroom powder supplemented with inorganic selenium(inSeMP)containing selenium(selenite)content of 0.3 mg/kg feed;(4)basal diet+mushroom powder enriched with organic selenium(orgSeMP)containing selenium(selenocysteine)content of 0.3 mg/kg feed.Mushroom powders were included at 6.5 g/kg of feed.Results In Period 1,there was no effect of diets on average daily gain(ADG)and gain:feed(G:F)ratio(P>0.05).The orgSeMP supplemented pigs had a lower average daily feed intake(ADFI)compared to all other groups(P<0.05).The ZnO supplemented pigs had reduced FS compared to the basal and mushroom group,while the orgSeMP supplemented pigs had lower FS compared to the basal group during the 21 d experimental period(P<0.05).In Period 2,there was no effect of diets on ADFI,ADG and G:F ratio(P>0.05).The orgSeMP supplementation increased the caecal abundance of bacterial members of the Firmicutes and Bacteroidetes phylum,including Lactobacillus,Agathobacter,Roseburia,and Prevotella and decreased the abundance of Sporobacter compared to the basal group,while inSeMP increased the caecal abundance of Prevotella and decreased the caecal abundance of Sporobacter compared to the basal group(P<0.05).Dietary supplementation with inSeMP increased expression of TLR4 and anti-inflammatory cytokine gene IL10 and decreased nutrient transporter gene FABP2 compared to the orgSeMP group(P<0.05).Conclusion OrgSeMP is a novel and sustainable way to incorporate selenium andβ-glucans into the diet of weaned pigs whilst improving FS and modulating the caecal microbiota.

Influence of heat treatment on microstructure,mechanical and corrosion behavior of WE43 alloy fabricated by laser-beam powder bed fusion

Magnesium(Mg)alloys are considered to be a new generation of revolutionary medical metals.Laser-beam powder bed fusion(PBF-LB)is suitable for fabricating metal implants withpersonalized and complicated structures.However,the as-built part usually exhibits undesirable microstructure and unsatisfactory performance.In this work,WE43 parts were firstly fabricated by PBF-LB and then subjected to heat treatment.Although a high densification rate of 99.91%was achieved using suitable processes,the as-built parts exhibited anisotropic and layeredmicrostructure with heterogeneously precipitated Nd-rich intermetallic.After heat treatment,fine and nano-scaled Mg24Y5particles were precipitated.Meanwhile,theα-Mg grainsunderwent recrystallization and turned coarsened slightly,which effectively weakened thetexture intensity and reduced the anisotropy.As a consequence,the yield strength and ultimate tensile strength were significantly improved to(250.2±3.5)MPa and(312±3.7)MPa,respectively,while the elongation was still maintained at a high level of 15.2%.Furthermore,the homogenized microstructure reduced the tendency of localized corrosion and favoredthe development of uniform passivation film.Thus,the degradation rate of WE43 parts was decreased by an order of magnitude.Besides,in-vitro cell experiments proved their favorable biocompatibility.

Influence of layer thickness on formation quality,microstructure,mechanical properties,and corrosion resistance of WE43 magnesium alloy fabricated by laser powder bed fusion

Laser powder bed fusion(L-PBF)of Mg alloys has provided tremendous opportunities for customized production of aeronautical and medical parts.Layer thickness(LT)is of great significance to the L-PBF process but has not been studied for Mg alloys.In this study,WE43 Mg alloy bulk cubes,porous scaffolds,and thin walls with layer thicknesses of 10,20,30,and 40μm were fabricated.The required laser energy input increased with increasing layer thickness and was different for the bulk cubes and porous scaffolds.Porosity tended to occur at the connection joints in porous scaffolds for LT40 and could be eliminated by reducing the laser energy input.For thin wall parts,a large overhang angle or a small wall thickness resulted in porosity when a large layer thicknesses was used,and the porosity disappeared by reducing the layer thickness or laser energy input.A deeper keyhole penetration was found in all occasions with porosity,explaining the influence of layer thickness,geometrical structure,and laser energy input on the porosity.All the samples achieved a high fusion quality with a relative density of over 99.5%using the optimized laser energy input.The increased layer thickness resulted to more precipitation phases,finer grain sizes and decreased grain texture.With the similar high fusion quality,the tensile strength and elongation of bulk samples were significantly improved from 257 MPa and 1.41%with the 10μm layer to 287 MPa and 15.12%with the 40μm layer,in accordance with the microstructural change.The effect of layer thickness on the compressive properties of porous scaffolds was limited.However,the corrosion rate of bulk samples accelerated with increasing the layer thickness,mainly attributed to the increased number of precipitation phases.

Alloy design for laser powder bed fusion additive manufacturing:a critical review

Metal additive manufacturing(AM)has been extensively studied in recent decades.Despite the significant progress achieved in manufacturing complex shapes and structures,challenges such as severe cracking when using existing alloys for laser powder bed fusion(L-PBF)AM have persisted.These challenges arise because commercial alloys are primarily designed for conventional casting or forging processes,overlooking the fast cooling rates,steep temperature gradients and multiple thermal cycles of L-PBF.To address this,there is an urgent need to develop novel alloys specifically tailored for L-PBF technologies.This review provides a comprehensive summary of the strategies employed in alloy design for L-PBF.It aims to guide future research on designing novel alloys dedicated to L-PBF instead of adapting existing alloys.The review begins by discussing the features of the L-PBF processes,focusing on rapid solidification and intrinsic heat treatment.Next,the printability of the four main existing alloys(Fe-,Ni-,Al-and Ti-based alloys)is critically assessed,with a comparison of their conventional weldability.It was found that the weldability criteria are not always applicable in estimating printability.Furthermore,the review presents recent advances in alloy development and associated strategies,categorizing them into crack mitigation-oriented,microstructure manipulation-oriented and machine learning-assisted approaches.Lastly,an outlook and suggestions are given to highlight the issues that need to be addressed in future work.

Influence of the Partial Substitution of Bitumen by a Mixture of Sulphur and Tyre and Plastic Bottle Powders on the Behaviour of Bituminous Concrete

This article deals with the influence of the partial substitution of bitumen by a mixture of sulphur and tyre and plastic bottle powders on the characterization of asphalt concrete. The approach adopted was to subject a control asphalt concrete to level 2 formulation tests as well as those modified at 10%, 20%, 30% and 40% by substituting bitumen with a mixture of tyre powder, plastic bottle powder and sulphur at 40%, 28% and 32% respectively. The results of the PCG, Duriez and rutting tests carried out on the control and modified bituminous concretes (manufactured using the wet process) revealed three (03) major findings, in particular with regard to workability, resistance to simple compression and rutting. The experimental results show an increasing trend in the essential parameters. At 40% substitution, there was a 22.73% increase in compactness, reflecting a significant improvement in the material’s workability. With regard to simple compressive strength, the increase is 34.02% at 40% substitution, highlighting the limitation of crack formation and propagation under heavy precipitation. With regard to rutting, the 16% drop in susceptibility at 40% substitution reflects a significant improvement in the behaviour of the material under dynamic mechanical stresses in heavy precipitation. The improvement in these behaviours results from the insertion of the plastic bottle powder into the interstices of the granular skeleton, thus reducing its cellular structure, and also from the interactions between the sulphur with the tyre powder and the sulphur with the plastic bottle powder, i.e. cross-linking or vulcanisation.

Microstructure and thermal properties of dissimilar M300–CuCr1Zr alloys by multi-material laser-based powder bed fusion

Multi-material laser-based powder bed fusion (PBF-LB) allows manufacturing of parts with 3-dimensional gradient and additional functionality in a single step. This research focuses on the combination of thermally-conductive CuCr1Zr with hard M300 tool steel.Two interface configurations of M300 on CuCr1Zr and CuCr1Zr on M300 were investigated. Ultra-fine grains form at the interface due to the low mutual solubility of Cu and steel. The material mixing zone size is dependent on the configurations and tunable in the range of0.1–0.3 mm by introducing a separate set of parameters for the interface layers. Microcracks and pores mainly occur in the transition zone.Regardless of these defects, the thermal diffusivity of bimetallic parts with 50vol% of CuCr1Zr significantly increases by 70%–150%compared to pure M300. The thermal diffusivity of CuCr1Zr and the hardness of M300 steel can be enhanced simultaneously by applying the aging heat treatment.

The Influence of Mesoscopic Characteristics of Mineral Powders Fillers on the Rutting Factor(G^(*)/sinδ)of Asphalt Mortar

This study aims to investigate the efiect of the mesoscopic characteristics of mineral powder fillers on the rutting resistance of asphalt mortar.Extraction and sieving tests were used to obtain the buton rock asphalt(BRA)ash with particle size smaller than 0.075 mm,which is consistent with that of the conventional mineral powder.The mesoscopic characteristics of BRA ash and conventional mineral powder were measured by SEM image analysis and the osmotic free pressure water method.Mesoscopic structure models of structural and free asphalts in mortar were obtained.The 70#matrix asphalt was used to prepare two kinds of asphalt mortar with BRA ash and conventional mineral powders fillers.The rutting factor of the two asphalt mortars was tested by dynamic shear test(DSR).Test results show that the ash extracted from BRA has a similar mesoscopic classification with the conventional mineral powder.Still,its fractal dimensions are larger,indicating the particles in BRA ash have more complex shapes and rougher surfaces,which is beneficial for forming structural asphalt and subsequently increasing the rutting factor(G*/sinδ),i e,improving the rutting resistance of the asphalt mortar.

Danggui Shaoyao powder improves hepatic lipid metabolism in atherosclerosis mice via PPARγ-LXRα-ABCA1 pathway regulation

Objective To observe the effects of Danggui Shaoyao powder(DSP)on hepatic lipid metabolism and further explore its mechanism of action by peroxisome proliferator-activated receptor(PPARγ)-liver X receptor(LXRα)-adenosine triphosphate(ATP)-binding cassette transporter A1(ABCA1)pathway regulation.Methods Eight C57BL/6J male mice were selected as the control group,and 24 ApoE^(−/−)male mice were randomly divided into the atherosclerosis model(AS)group,atorvastatin calcium(AC)group,and DSP group(n=8 each group).To establish an AS model,ApoE^(−/−)mice were fed a high-fat diet for 16 weeks.Pathologic changes in the aortic vasculature and liver were identified using Oil Red O staining.Triglyceride(TG),cholesterol(TC),and low-density lipoprotein cholesterol(LDL-C)levels were determined in the livers using a single-reagent GPO-PAP method.Fluorescence quantitative polymerase chain reaction and western blot were used to observe and evaluate the mRNA and protein expression of the PPARγ-LXRα-ABCA1 intermediates in the liver.Results After 16 weeks of a high-fat diet,ApoE−/−mice showed more Oil Red O staining in the aorta and liver compared to the CONT group.Compared to the AS group,the DSP and AC treatment reduced aortic plaque and hepatic lipid deposition to varying degrees.Furthermore,DSP significantly reduced the hepatic lipid area in ApoE^(−/−)mice(P<.001)and decreased the levels of TG,TC,and LDL-C in liver(P<.001,P=.027,P<.001,respectively).DSP also significantly increased the levels of PPARγ,LXRα,ABCA1,and ABCG1 mRNA expression,as well as the PPARγ,LXRα,ABCA1,and ABCG1 protein expression in liver.Conclusion DSP improved hepatic lipid metabolism via PPARγ-LXRα-ABCA1 pathway modulation for AS treatment.

Micro-aluminum powder with bi-or tri-component alloy coating as a promising catalyst:Boosting pyrolysis and combustion of ammonium perchlorate

A novel design of micro-aluminum(μAl)powder coated with bi-/tri-component alloy layer,such as:Ni-P and Ni-P-Cu(namely,Al@Ni-P,Al@Ni-P-Cu,respectively),as combustion catalysts,were introduced to release its huge energy inside Al-core and promote rapid pyrolysis of ammonium perchlorate(AP)at a lower temperature in aluminized propellants.The microstructure of Al@Ni-P-Cu demonstrates that a three-layer Ni-P-Cu shell,with the thickness of~100 nm,is uniformly supported byμAl carrier(fuel unit),which has an amorphous surface with a thickness of~2.3 nm(catalytic unit).The peak temperature of AP with the addition of Al@Ni-P-Cu(3.5%)could significantly drop to 316.2℃ at high-temperature thermal decomposition,reduced by 124.3℃,in comparison to that of pure AP with 440.5℃.It illustrated that the introduction of Al@Ni-P-Cu could weaken or even eliminate the obstacle of AP pyrolysis due to its reduction of activation energy with 118.28 kJ/mol.The laser ignition results showed that the ignition delay time of Al@Ni-P-Cu/AP mixture with 78 ms in air is shorter than that of Al@Ni-P/AP(118 ms),decreased by 33.90%.Those astonishing breakthroughs were attributed to the synergistic effects of adequate active sites on amorphous surface and oxidation exothermic reactions(7597.7 J/g)of Al@Ni-P-Cu,resulting in accelerated mass and/or heat transfer rate to catalyze AP pyrolysis and combustion.Moreover,it is believed to provide an alternative Al-based combustion catalyst for propellant designer,to promote the development the propellants toward a higher energy.

Microstructure evolution and strengthening mechanism of high -performance powder metallurgy TA15 titanium alloy by hot rolling

Hot deformation of sintered billets by powder metallurgy(PM)is an effective preparation technique for titanium alloys,which is more significant for high-alloying alloys.In this study,Ti–6.5Al–2Zr–Mo–V(TA15)titanium alloy plates were prepared by cold press-ing sintering combined with high-temperature hot rolling.The microstructure and mechanical properties under different process paramet-ers were investigated.Optical microscope,electron backscatter diffraction,and others were applied to characterize the microstructure evolution and mechanical properties strengthening mechanism.The results showed that the chemical compositions were uniformly dif-fused without segregation during sintering,and the closing of the matrix craters was accelerated by increasing the sintering temperature.The block was hot rolled at 1200℃ with an 80%reduction under only two passes without annealing.The strength and elongation of the plate at 20–25℃ after solution and aging were 1247 MPa and 14.0%,respectively,which were increased by 24.5%and 40.0%,respect-ively,compared with the as-sintered alloy at 1300℃.The microstructure was significantly refined by continuous dynamic recrystalliza-tion,which was completed by the rotation and dislocation absorption of the substructure surrounded by low-angle grain boundaries.After hot rolling combined with heat treatment,the strength and plasticity of PM-TA15 were significantly improved,which resulted from the dense,uniform,and fine recrystallization structure and the synergistic effect of multiple slip systems.

Ballistic performance of titanium-based layered composites made using blended elemental powder metallurgy and hot isostatic pressing

Metal matrix composites tiles based on Ti-6Al-4V(Ti64)alloy,reinforced with 10,20,and 40(vol%)of either TiC or TiB particles were made using press-and-sinter blended elemental powder metallurgy(BEPM)and then bonded together into 3-layer laminated plates using hot isostatic pressing(HIP).The laminates were ballistically tested and demonstrated superior performance.The microstructure and properties of the laminates were analyzed to determine the effect of the BEPM and HIP processing on the ballistic properties of the layered plates.The effect of porosity in sintered composites on further diffusion bonding of the plates during HIP is analyzed to understand the bonding features at the interfaces between different adjacent layers in the laminate.Exceptional ballistic performance of fabricated structures was explained by a significant reduction in the residual porosity of the BEPM products by their additional processing using HIP,which provides an unprecedented increase in the hardness of the layered composites.It is argued that the combination of the used two technologies,BEPM and HIP is principally complimentary for the materials in question with the abilities to solve the essential problems of each used individually.

Lactose-free milk powder can effectively relieve diarrhea symptoms in weaning SD rats and children

Diarrhea has become the leading cause of illness and death among infants and young children in developing countries.Clinically,patients with diarrhea showed damaged intestinal epithelial villi,usually accompanied by lactase deficiency.In this study,we evaluated the therapeutic effects of lactose-free milk powder on rats and children with diarrhea.Antibiotic-associated diarrhea(AAD)model was established by gavage with antibiotic mixture in SD rats,followed by administration of milk powder containing lactose or not.The results showed that lactose-free milk powder ameliorated A AD-related diarrhea symptoms,and accelerated the recovery from diarrhea.And 16S sequencing results indicated lactose-free milk powder contributed to increase theα-andβ-diversity of intestinal flora,and restore the intestinal microbiota disorder.In conclusion,our data demonstrate that lactose-free milk powder could alleviate diarrhea by restoring gut microbiota and intestinal barrier function.