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Identifying user intent through query refinements
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作者 Xiaojuan ZHANG Wei LU 《Chinese Journal of Library and Information Science》 2013年第3期1-14,共14页
Purpose:In this paper,we attempt to use query refinements to identify users' search intents and seek a method for intent clustering based on real world query data.Design/methodology/approach:An experiment has been... Purpose:In this paper,we attempt to use query refinements to identify users' search intents and seek a method for intent clustering based on real world query data.Design/methodology/approach:An experiment has been conducted to analyze selected search sessions from the American Online(AOL) query logs with a two-stage approach.The first stage is to identify underlying intent by combining query co-occurrence information with query expression similarity.The work in the second stage is to cluster identified results by constructing query vectors through performing random walks on a Markov graph.Findings:Average correctness for identifying search intent is 0.74.Precision,recall,F-score values for intent clustering are 0.73,0.72 and 0.71,respectively.The results indicate that combining session co-occurrence information and query expression similarity can further filter noises and our clustering method is more suitable for sparse data.Research limitations:We use the time-out threshold(15-minutc) method to group queries in one session,but a user may have multiple search goals at the same time and the multi-task behavior of a user is hard to capture in a session defined based on time notions.Practical implications:This study provides insights into the ways of understanding users' search intents by analyzing their queries and refinements from a new perspective.The results will help search engine developers to identify user intents.Originality/value:We propose a new method to identify users' search intents by combining session co-occurrence information and query expression similarity,and a new method for clustering sparse data. 展开更多
关键词 Query intent Query refinement Random walk Intent clustering
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REFINEMENTS OF THE FAN-TODD'S INEQUALITIES
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作者 K. K. CHONG Department of Applied Mathematics, The Hong Kong Polytechnic University Hong Kong, China. E-mail:makkchon@inet.po1yu.edu.hk 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2002年第1期75-84,共10页
Refinements to inequalities on inner product spaces are presented. In this respect, inequali-ties dealt with in this paper are: Cauchy’s inequality, Bessel’s inequality, Fan-Todd’s inequality and Fan-Todd’s determ... Refinements to inequalities on inner product spaces are presented. In this respect, inequali-ties dealt with in this paper are: Cauchy’s inequality, Bessel’s inequality, Fan-Todd’s inequality and Fan-Todd’s determinantal inequality. In each case, a strictly increasing function is put for-ward, which lies between the smaller and the larger quantities of each inequality. As a result. an improved condition for equality of the Fan-Todd’s determinantal inequality is deduced. 展开更多
关键词 Cauchy's inequality Bessel's inequality Fan-Todd's inequality Fan-Todd's determinantal inequality refinements of inequalities
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Tensile failure mode transitions from subzero to elevated deformation temperature in Mg-6Al-1Zn alloy
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作者 Hafiz Muhammad Rehan Tariq Umer Masood Chaudry +3 位作者 Jeong-Rim Lee Nooruddin Ansari Mansoor Ali Tea-Sung Jun 《International Journal of Minerals,Metallurgy and Materials》 2026年第1期242-251,共10页
Understanding the temperature dependent deformation behavior of Mg alloys is crucial for their expanding use in the aerospace sector.This study investigates the deformation mechanisms of hot-rolled AZ61 Mg alloy under... Understanding the temperature dependent deformation behavior of Mg alloys is crucial for their expanding use in the aerospace sector.This study investigates the deformation mechanisms of hot-rolled AZ61 Mg alloy under uniaxial tension along rolling direction(RD)and transverse direction(TD)at-50,25,50,and 150℃.Results reveal a transition from high strength with limited elongation at-50℃ to significant softening and maximum ductility at 150℃.TD samples consistently showed 2%-6%higher strength than RD;however,this yield anisotropy diminished at 150℃ due to the shift from twinning to thermally activated slip and recovery.Fractography indicated a change from semi-brittle to fully ductile fracture with increasing temperature.Electron backscattered diffraction(EBSD)analysis confirmed twinning-driven grain refinement at low temperatures,while deformation at high temperatures involved grain elongation along shear zones,enabling greater strain accommodation before material failure. 展开更多
关键词 Mg alloy deformation temperature twinning dynamics grain refinement dynamic recovery fracture mechanics
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Do Higher Horizontal Resolution Models Perform Better?
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作者 Shoji KUSUNOKI 《Advances in Atmospheric Sciences》 2026年第1期259-262,共4页
Climate model prediction has been improved by enhancing model resolution as well as the implementation of sophisticated physical parameterization and refinement of data assimilation systems[section 6.1 in Wang et al.(... Climate model prediction has been improved by enhancing model resolution as well as the implementation of sophisticated physical parameterization and refinement of data assimilation systems[section 6.1 in Wang et al.(2025)].In relation to seasonal forecasting and climate projection in the East Asian summer monsoon season,proper simulation of the seasonal migration of rain bands by models is a challenging and limiting factor[section 7.1 in Wang et al.(2025)]. 展开更多
关键词 enhancing model resolution refinement data assimilation systems section climate model climate projection higher horizontal resolution seasonal forecasting simulation seasonal migration rain bands model resolution
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On hp refinements of independent cover numerical manifold method——some strategies and observations 被引量:3
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作者 ZHANG Ning ZHENG Hong +1 位作者 LI Xu WU WenAn 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2023年第5期1335-1351,共17页
In this paper,strategies are provided for a powerful numerical manifold method(NMM)with h and p refinement in analyses of elasticity and elasto-plasticity.The new NMM is based on the concept of the independent cover,w... In this paper,strategies are provided for a powerful numerical manifold method(NMM)with h and p refinement in analyses of elasticity and elasto-plasticity.The new NMM is based on the concept of the independent cover,which gets rid of NMM's important defect of rank deficiency when using higher-order local approximation functions.Several techniques are presented.In terms of mesh generation,a relationship between the quadtree structure and the mathematical mesh is established to allow a robust h-refinement.As to the condition number,a scaling based on the physical patch is much better than the classical scaling based on the mathematical patch;an overlapping width of 1%–10%can ensure a good condition number for 2nd,3rd,and 4th order local approximation functions;the small element issue can be overcome after the local approximation on small patch is replaced by that on a regular patch.On numerical accuracy,local approximation using complete polynomials is necessary for the optimal convergence rate.Two issues that may damage the convergence rate should be prevented.The first is to approximate the curved boundary of a higher-order element by overly few straight lines,and the second is excessive overlapping width.Finally,several refinement strategies are verified by numerical examples. 展开更多
关键词 independent cover numerical manifold method hp refinement partition of unity higher order element condition number
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REFINEMENTS OF THE MATHIEU INEQUALITY
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作者 王中烈 王兴华 《Chinese Science Bulletin》 SCIE EI CAS 1982年第1期122-,共1页
and c is a positive number. In 1952, L. Berg proved the conjecture. In 1976, P. H. Diananda refined the result
关键词 refined CONJECTURE 田毛
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Technical refinements of the modified central mound breast reduction
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作者 Simon Nicholson Muhammad Adil Abbas Khan Muhammad Riaz 《Plastic and Aesthetic Research》 2018年第9期1-11,共11页
Aim: Common pitfalls with existing breast reduction techniques include poor aesthetic outcome, such as development of a 'boxy' breast shape, and pseudoptosis. Presented here are a series of modifications to th... Aim: Common pitfalls with existing breast reduction techniques include poor aesthetic outcome, such as development of a 'boxy' breast shape, and pseudoptosis. Presented here are a series of modifications to the technique of central mound breast reduction, based on previous work, aimed at ensuring consistent aesthetic results which are maintained in the long-term. Methods: All patients undergoing bilateral breast reduction by the senior author over a 7-year period were included, with outcome data collected prospectively. A detailed description of the technique is offered. Results: One hundred and sixteen patients underwent bilateral breast reduction over the study period. Mean follow-up was 20.6 months. There were no cases of nipple necrosis or infection requiring antibiotics. There was one post-operative haematoma which required surgical evacuation. Three patients developed a degree of fat necrosis which was managed conservatively in two, but required surgical debridement for liquefactive necrosis in one. Results of these breast reductions at the second post-operative year and beyond are presented. Conclusion: The technique described offers benefits of improved predictability, consistency and longevity of aesthetic results over existing techniques. Development of pseudoptosis in particular is effectively delayed. The modifications described have not been shown to increase the rates of surgical complications. 展开更多
关键词 CENTRAL mound BREAST reduction MASTOPEXY technique TECHNICAL REFINEMENT modification
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Design Refinement of Catalytic System for Scale-Up Mild Nitrogen Photo-Fixation 被引量:1
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作者 Xiao Hu Wang Bin Wu +4 位作者 Yongfa Zhu Dingsheng Wang Nian Bing Li Zhichuan J.Xu Hong Qun Luo 《Nano-Micro Letters》 2025年第8期111-170,共60页
Ammonia and nitric acid,versatile industrial feedstocks,and burgeoning clean energy vectors hold immense promise for sustainable development.However,Haber–Bosch and Ostwald processes,which generates carbon dioxide as... Ammonia and nitric acid,versatile industrial feedstocks,and burgeoning clean energy vectors hold immense promise for sustainable development.However,Haber–Bosch and Ostwald processes,which generates carbon dioxide as massive by-product,contribute to greenhouse effects and pose environmental challenges.Thus,the pursuit of nitrogen fixation through carbon–neutral pathways under benign conditions is a frontier of scientific topics,with the harnessing of solar energy emerging as an enticing and viable option.This review delves into the refinement strategies for scale-up mild photocatalytic nitrogen fixation,fields ripe with potential for innovation.The narrative is centered on enhancing the intrinsic capabilities of catalysts to surmount current efficiency barriers.Key focus areas include the in-depth exploration of fundamental mechanisms underpinning photocatalytic procedures,rational element selection,and functional planning,state-of-the-art experimental protocols for understanding photo-fixation processes,valid photocatalytic activity evaluation,and the rational design of catalysts.Furthermore,the review offers a suite of forward-looking recommendations aimed at propelling the advancement of mild nitrogen photo-fixation.It scrutinizes the existing challenges and prospects within this burgeoning domain,aspiring to equip researchers with insightful perspectives that can catalyze the evolution of cutting-edge nitrogen fixation methodologies and steer the development of next-generation photocatalytic systems. 展开更多
关键词 Scale-up Mild nitrogen photo-fixation Design refinements Catalyst system Environmental sustainability
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Point-voxel dual transformer for LiDAR 3D object detection
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作者 TONG Jigang YANG Fanhang +1 位作者 YANG Sen DU Shengzhi 《Optoelectronics Letters》 2025年第9期547-554,共8页
In this paper,a two-stage light detection and ranging(LiDAR) three-dimensional(3D) object detection framework is presented,namely point-voxel dual transformer(PV-DT3D),which is a transformer-based method.In the propos... In this paper,a two-stage light detection and ranging(LiDAR) three-dimensional(3D) object detection framework is presented,namely point-voxel dual transformer(PV-DT3D),which is a transformer-based method.In the proposed PV-DT3D,point-voxel fusion features are used for proposal refinement.Specifically,keypoints are sampled from entire point cloud scene and used to encode representative scene features via a proposal-aware voxel set abstraction module.Subsequently,following the generation of proposals by the region proposal networks(RPN),the internal encoded keypoints are fed into the dual transformer encoder-decoder architecture.In 3D object detection,the proposed PV-DT3D takes advantage of both point-wise transformer and channel-wise architecture to capture contextual information from the spatial and channel dimensions.Experiments conducted on the highly competitive KITTI 3D car detection leaderboard show that the PV-DT3D achieves superior detection accuracy among state-of-the-art point-voxel-based methods. 展开更多
关键词 proposal refinement encode representative scene features point voxel dual transformer object detection LIDAR d object detection generation proposals proposal refinementspecificallykeypoints
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Effects of grain size on the corrosion inhibition and adsorption performance of benzotriazole on carbon steel in NaCl solution 被引量:1
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作者 Panjun Wang Jinke Wang +8 位作者 Yao Huang Xuequn Cheng Zhiwei Zhao Lingwei Ma Shun Wang Ruijie Han Zichang Zhang Dawei Zhang Xiaogang Li 《Journal of Materials Science & Technology》 2025年第14期221-236,共16页
This study investigates the adsorption mechanism,the film formation process,and the inhibition performance of benzotriazole(BTAH)on carbon steels with different grain sizes(i.e.,24.5,4.3,and 0.6μm)in 3.5 wt.%NaCl sol... This study investigates the adsorption mechanism,the film formation process,and the inhibition performance of benzotriazole(BTAH)on carbon steels with different grain sizes(i.e.,24.5,4.3,and 0.6μm)in 3.5 wt.%NaCl solution.The results demonstrate that grain refinement significantly impacts the adsorption and inhibition performance of BTAH on carbon steels.Ultra-refinement of steel grains to 0.6μm improves the maximum inhibition efficiency of BTAH to 90.0%within 168 h of immersion,which was much higher than that of the steels with 24.5μm(73.6%)and 4.3μm grain sizes(81.7%).Notably,grain sizes of 4.3 and 0.6μm facilitate a combination of physisorption and chemisorption of BTAH after 120 h of immersion,as evidenced by the X-ray photoelectron spectroscopy(XPS)results and Langmuir adsorption isotherms,while BTAH adsorbed on carbon steels with a grain size of 24.5μm through physisorption during the 168 h of immersion.Ultra-refinement of grains has beneficial impacts on promoting the formation of a stable and dense corrosion inhibitor film,leading to improved corrosion resistance and the mitigation of non-uniform corrosion.These advantageous effects can be attributed to the higher adsorption energy at grain boundaries(approximately-3.12 eV)compared to grain interiors(ranging from-0.79 to 2.47 eV),promoting both the physisorption and chemisorption of organic corrosion inhibitors.The investigation comprehensively illustrates,for the first time,the effects of grain size on the adsorption mechanism,film formation process,and inhibition performance of organic corrosion inhibitors on carbon steels.This study demonstrates a promising approach to enhancing corrosion inhibition performance through microstructural design. 展开更多
关键词 Carbon steel Corrosion inhibitor Grain refinement MICROSTRUCTURE Adsorption mechanism
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Effect of La on inclusion evolution and solidification structure of 40Cr steel 被引量:1
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作者 Wang-wang Mao Yan-chong Yu +4 位作者 Le-ru Zhang Jin-ling Zhang Wei Yan An-min Zheng She-bin Wang 《Journal of Iron and Steel Research International》 2025年第6期1678-1690,共13页
Rare earth La was introduced into 40Cr steel in industrial experiments to achieve the purpose of modifying inclusions.The impact of La on the inclusion modification was studied,and its influence on the solidification ... Rare earth La was introduced into 40Cr steel in industrial experiments to achieve the purpose of modifying inclusions.The impact of La on the inclusion modification was studied,and its influence on the solidification structure was further investigated.With adding 0.0023%La,the Al_(2)O_(3)·CaO·CaS inclusions were modified to the LaAlO_(3)·CaO·CaS inclusions.Additionally,the morphology tended to be more spherical,and the proportion of small-sized inclusions increased significantly from 77.8%to 93.5%.The large-sized inclusions were almost completely eliminated.Based on experimental results,a dynamical model elucidating the process of inclusion modification by La was developed.Furthermore,the ratio of equiaxed zone of the solidification structure increased from 22.9%to 31.0%,and the average primary dendrite arm spacing decreased significantly from 288.4 to 226.2μm.Two-dimensional lattice mismatch analysis results determined that LaAlO_(3)can serve as an effective heterogeneous nucleation core,leading to solidification structure refinement.The beneficial transformation of inclusions and refinement of solidification structure are conducive to the cold heading process of 40Cr steel. 展开更多
关键词 40Cr steel LA Inclusion modification Structure refinement Dynamical model
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Exceptional grain refinement induced by dispersed MgO particles in TIG-welded AZ31 alloy 被引量:1
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作者 Le Zai Xin Tong +2 位作者 Yun Wang Hao Zhang Xiaohuai Xue 《Journal of Materials Science & Technology》 2025年第2期1-13,共13页
Due to the low content of alloying elements and the lack of effective nucleation sites,the fusion zone(FZ)of tungsten inert gas(TIG)welded AZ31 alloy typically exhibits undesirable coarse columnar grains,which can res... Due to the low content of alloying elements and the lack of effective nucleation sites,the fusion zone(FZ)of tungsten inert gas(TIG)welded AZ31 alloy typically exhibits undesirable coarse columnar grains,which can result in solidification defects and reduced mechanical properties.In this work,a novel welding wire containing MgO particles has been developed to promote columnar-to-equiaxed transition(CET)in the FZ of TIG-welded AZ31 alloy.The results show the achievement of a fully equiaxed grain structure in the FZ,with a significant 71.9%reduction in grain size to 41 μm from the original coarse columnar dendrites.Furthermore,the combination of using MgO-containing welding wire and pulse current can further refine the grain size to 25.6 μm.Microstructural analyses reveal the homogeneous distribution of MgO particles in the FZ.The application of pulse current results in an increase in the number density of MgO(1-2 μm)from 5.16 × 10^(4) m^(-3) to 6.18 × 10^(4) m^(-3).The good crystallographic matching relationship between MgO and α-Mg matrix,characterized by the orientation relationship of[11(2)0]α-Mg//[0(1)1]MgO and(0002)_(α-Mg)//(111)_(MgO),indicates that the MgO particles can act as effective nucleation sites for α-Mg to reduce nucleation undercooling.According to the Hunt criteria,the critical temperature gradient for CET is greatly enhanced due to the significantly increased number density of MgO nucleation sites.In addition,the correlation with the thermal simulation results reveals a transition in the solidification conditions within the welding pool from the columnar grain zone to the equiaxed grain zone in the CET map,leading to the realization of CET.The exceptional grain refinement has contributed to a simultaneous improvement in the strength and plasticity of welded joints.This study presents a novel strategy for controlling equiaxed microstructure and optimizing mechanical properties in fusion welding or wire and arc additive manufacturing of Mg alloy components. 展开更多
关键词 AZ31 alloy TIG welding Columnar-to-equiaxed transition Grain refinement Heterogeneous nucleation
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In-situ observation on dissolution of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions in refining slag 被引量:1
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作者 Yu-die Gu Ying Ren Li-feng Zhang 《Journal of Iron and Steel Research International》 2025年第2期376-387,共12页
The dissolution behavior of complex inclusions in refining slag was studied using confocal laser scanning microscope.Based on the dissolution curve of complex inclusions,the main rate-limiting link of CaO-SiO_(2)-Al_(... The dissolution behavior of complex inclusions in refining slag was studied using confocal laser scanning microscope.Based on the dissolution curve of complex inclusions,the main rate-limiting link of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was the diffusion in the molten slag.The dissolution rate of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was affected by the composition and size of inclusion.The functional relationship between the dimensionless inclusion capacity(Zh)and the dimensionless dissolution rate(Ry)of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was calculated as Ry=2.10×10^(-6)Zh^(0.160),while it was Ry=2.10×10^(-6)Zh^(0.0087)for Al_(2)O_(3)-CaO complex inclusions.On this basis,the complete dissolution time and rate of the complex inclusions were calculated by using the function relation between the Zh and Ry numbers. 展开更多
关键词 INCLUSION Confocal laser scanning microscope Refining slag Dissolution kinetics
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Simultaneous improvement of strength and ductility in a P-doped CrCoNi medium-entropy alloy 被引量:1
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作者 Hangzhou Zhang Guoqiang Sun +2 位作者 Muxin Yang Fuping Yuan Xiaolei Wu 《Journal of Materials Science & Technology》 2025年第6期128-138,共11页
A newly developed P-doped CrCoNi medium-entropy alloy(MEA)provides both higher yield strength and larger uniform elongation than the conventional CrCoNi MEA,even superior tensile ductility to the other-element-doped C... A newly developed P-doped CrCoNi medium-entropy alloy(MEA)provides both higher yield strength and larger uniform elongation than the conventional CrCoNi MEA,even superior tensile ductility to the other-element-doped CrCoNi MEAs at similar yield strength levels.P segregation at grain boundaries(GBs)and dissolution inside grain interiors,together with the related lower stacking fault energy(SFE)are found in the P-doped CrCoNi MEA.Higher hetero-deformation-induced(HDI)hardening rate is observed in the P-doped CrCoNi MEA due to the grain-to-grain plastic deformation and the dynamic structural refinement by high-density stacking fault-walls(SFWs).The enhanced yield strength in the P-doped CoCrNi MEA can be attributed to the strong substitutional solid-solution strengthening by severer lattice distortion and the GB strengthening by phosphorus segregation at GBs.During the tensile deformation,the multiple SFW frames inundated with massive multi-orientational tiny planar stacking faults(SFs)between them,rather than deformation twins,are observed to induce dynamic structural refinement for forming par-allelepiped domains in the P-doped CoCrNi MEA,due to the lower SFE and even lower atomically-local SFE.These nano-sized domains with domain boundary spacing at tens of nanometers can block disloca-tion movement for strengthening on one hand,and can accumulate defects in the interiors of domains for exceptionally high hardening rate on the other hand. 展开更多
关键词 Tensile ductility Dynamic grain refinement Stacking fault energy Strain hardening Phosphorus segregation
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Development and clinical evaluation of a supramolecular acid-enzyme complex for skin exfoliation,sebum control,and pore refinement 被引量:1
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作者 Huwu Zhou Wenrong Zhang +3 位作者 Xuewan Li Rongrong Li Changzhi Dong Lifeng Tang 《Journal of Dermatologic Science and Cosmetic Technology》 2025年第3期37-44,共8页
Background:Enzyme fragility remains a major challenge in research and applications.Free enzymes are highly unstable,inactivated by heat,acid,alkali,or organic solvents,and often lose activity even under optimal storag... Background:Enzyme fragility remains a major challenge in research and applications.Free enzymes are highly unstable,inactivated by heat,acid,alkali,or organic solvents,and often lose activity even under optimal storage conditions.Limiting their use in cosmetics.Few commercial products combine acids and enzymes effectively.Objective:To investigate the physicochemical properties,in vitro exfoliation efficacy,and effects on facial skin parameters of a supramolecular acid-enzyme complex(SAE)composed of mandelic acid(MAN),betaine(BET),and composite enzymes(CE;papain and bromelain),thereby establishing a theoretical foundation for cosmetic applications.Methods:The supramolecular structure was characterized using Fourier transform infrared(FTIR)spectroscopy and proton nuclear magnetic resonance(1H NMR)spectroscopy.Dissolution experiments were conducted to compare the solubility of SAE and CE in aqueous solutions.Enzymatic activity assays evaluated the stabilizing effect of supramolecular deep eutectic technology on enzymes.In vitro exfoliation tests assessed acid-enzyme synergy in keratin removal.A 4-week clinical trial evaluated the efficacy of a 2%SAE essence aqueous solution on facial skin parameters.Results:Dissolution experiments confirmed that supramolecular deep eutectic technology significantly improved enzyme solubility.Enzymatic activity tests demonstrated that this technology effectively preserved protease activity,substantially enhancing its practical applicability.Furthermore,in vitro exfoliation efficacy tests revealed that this technology strengthened the synergistic interaction between acids and enzymes and exhibited superior stratum corneum-removing capability of the SAE.In clinical evaluations of efficacy,after 7 days of using the essence containing SAE,the formulation significantly enhanced cheek gloss(+8.08%),while reducing comedones volume(-16.25%).after 28 days,significantly enhanced cheek hydration(+25.0%,SCH),gloss(+15.93%),and smoothness(−7.78%SEsm),while reducing TEWL(−6.86%),sebum(−15.54%),roughness(+16.24%SEr),and pore metrics(volume:−39.98%;count:−30.64%),and decreased comedones(blackheads:−70.33%;Whiteheads:−52.42%;all p<0.05).Conclusion:The supramolecular acid-enzyme complex demonstrates enhanced stability,improved solubility,and superior exfoliation efficacy compared to free enzymes.Clinical results further confirm its multifunctional benefits,including enhancing skin hydration,sebum regulation,barrier repair,pore refinement,and comedolytic effects.This study provides both theoretical and practical foundations for developing stable acid-enzyme combinations in dermatological applications. 展开更多
关键词 Supramolecular acid-enzyme complex Acid-enzyme synergy Enzymatic stability Cosmetic exfoliation Sebum regulation Pore refinement Comedolytic effects
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A novel fine-grained TiZrCu alloy tailored for marine environment with high microbial corrosion-resistance 被引量:1
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作者 Jiaqi Li Xi Ouyang +8 位作者 Diaofeng Li Hang Yu Yaozong Mao Qing Jia Zhiqiang Zhang Mingxing Zhang Chunguang Bai Fuhui Wang Dake Xu 《Journal of Materials Science & Technology》 2025年第19期315-330,共16页
Titanium alloys,usually known as non-corrodible material,are susceptible to microbiologically influenced corrosion(MIC)in marine environment.While titanium-zirconium(TiZr)alloys have been extensively studied in medica... Titanium alloys,usually known as non-corrodible material,are susceptible to microbiologically influenced corrosion(MIC)in marine environment.While titanium-zirconium(TiZr)alloys have been extensively studied in medical applications,the influence of microorganisms,especially marine microorganisms,on their corrosion behavior has not been explored.In this work,a TiZrCu alloy with a combination of excel-lent mechanical,anti-corrosion,and antibacterial properties was developed by optimizing the Cu content and grain refinement.Its MIC and antibacterial mechanisms against Pseudomonas aeruginosa,a represen-tative marine microorganism,were systematically investigated.5.5 wt%was determined as the optimal copper content.The fine-grained Ti-15Zr-5.5Cu(TZC-5.5FG)alloy maintained high MIC resistance,exhibit-ing a corrosion current of 5.7±0.1 nA/cm^(2) and an antibacterial rate of 91.8% against P.aeruginosa.The mechanism of improved corrosion resistance was attributed to the denser passive film with high TiO2 content and the lower surface potential differenceΔE.The release of Cu^(2+)ions,ΔE,and the generation of ROS are three major factors that contribute to the antibacterial performance of TiZrCu alloys.Com-pared to other available marine metals,TZC-5.5FG alloy exhibited superior comprehensive performance,including excellent mechanical properties and anti-MIC capacity,which make it a promising material for load-bearing applications in marine environment. 展开更多
关键词 Multifunctional titanium-zirconium alloys Grain refinement Microbiologically influenced corrosion resistance Antibacterial mechanism Mechanical property
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Laser additive manufacturing of Ti and Ce co-modified 2195 difficult-to-process aluminum alloy:Grain refinement,cracking suppression and enhanced mechanical properties 被引量:1
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作者 Lixia XI Jiaxing HOU +3 位作者 Juncan XU He LIU Keyu SHI Dongdong GU 《Chinese Journal of Aeronautics》 2025年第8期604-621,共18页
High cracking susceptibility of Al-Li alloys with Ti/Ce B6addition is thoroughly suppressed in laser powder bed fusion(LPBF)processing of Ti/Ce co-modified 2195 alloys at relatively high scan speeds,while the cracking... High cracking susceptibility of Al-Li alloys with Ti/Ce B6addition is thoroughly suppressed in laser powder bed fusion(LPBF)processing of Ti/Ce co-modified 2195 alloys at relatively high scan speeds,while the cracking suppression mechanism and phase formation in these composites are not clarified.In this work,microstructure evolution and mechanical performance of the LPBF-fabricated Ti/Ce co-modified 2195 are investigated to reveal their cracking suppression and strengthening mechanisms.The results show that apparent grain refinement of the composites is ascribed to high supercooling from rapid formation of constitutional supercooling zone in front of solid–liquid interfaces by high-Q-value Ti solute,and heterogeneous nucleation of in situ formed Al3Ti and Al11Ce3precipitates.Their synergistic interactions promote formation of fine equiaxed grains and thus inhibit crack initiation.The composites exhibit high microhardness of 100±5HV0.2,nano-hardness of 1.6±0.1 GPa and elastic modulus of 97±3 GPa,where the elastic modulus increases by 27%and 31%compared to those of LPBF-processed and conventionally manufactured 2195 alloys,respectively.A tensile strength of 336 MPa and an elongation of 3%are obtained from in-situ synchrotron X-ray diffraction measurement.The improved properties are derived from grain refinement and Orowan strengthening.Based on the optimal processing parameter and composition,a bracket component filled with lattice structures is designed and manufactured with good manufacturing quality and processing accuracy. 展开更多
关键词 Laser powder bed fusion Ti/Ce co-modified 2195 alloy Grain refinement Cracking suppression Mechanical property
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Synchronous enhancement of corrosion resistance and mechanical properties of Mg-Zn-Ca alloys by grain refinement using equal channel angular pressing 被引量:1
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作者 Yi-zhuo WANG Xiao-ping LUO +6 位作者 Gang-xiao REN Hong-xia WANG Li-fei WANG Wei-li CHENG Hang LI Xiao-peng LU Kwang-seon SHIN 《Transactions of Nonferrous Metals Society of China》 2025年第6期1772-1786,共15页
To investigate the effect of microstructure evolution on corrosion behavior and strengthening mechanism of Mg-1Zn-1Ca(wt.%)alloys,as-cast Mg-1Zn-1Ca alloys were performed by equal channel angular pressing(ECAP)with 1 ... To investigate the effect of microstructure evolution on corrosion behavior and strengthening mechanism of Mg-1Zn-1Ca(wt.%)alloys,as-cast Mg-1Zn-1Ca alloys were performed by equal channel angular pressing(ECAP)with 1 and 4 passes.The corrosion behavior and mechanical properties of alloys were investigated by optical microscopy(OM),scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),electrochemical tests,immersion tests and tensile tests.The results showed that mechanical properties improved after ECAP 1 pass;however,the corrosion resistance deteriorated due to high-density dislocations and fragmented secondary phases by ECAP.In contrast,synchronous improvement in the mechanical properties and corrosion resistance was achieved though grain refinement after ECAP 4 passes;fine grains led to a significant improvement in the yield strength,ultimate tensile strength,elongation,and corrosion rate of 103 MPa,223 MPa,30.5%,and 1.5843 mm/a,respectively.The enhanced corrosion resistance was attributed to the formation of dense corrosion product films by finer grains and the barrier effect by high-density grain boundaries.These results indicated that Mg-1Zn-1Ca alloy has a promising potential for application in biomedical materials. 展开更多
关键词 Mg−1Zn−1Ca alloy equal channel angular pressing grain refinement corrosion behavior mechanical properties
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Preparation of 7N High-Purity Indium by Vacuum Distillation-Zone Refining Combination
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作者 Tian Qinghua Hu Zhixiang +3 位作者 He Zhiqiang Guo Xueyi Zhu Liu Xu Zhipeng 《稀有金属材料与工程》 北大核心 2025年第8期1947-1955,共9页
High-purity indium finds extensive application in the aerospace,electronics,medical,energy,and national defense sectors.Its purity and impurity contents significantly influence its performance in these applications.Hi... High-purity indium finds extensive application in the aerospace,electronics,medical,energy,and national defense sectors.Its purity and impurity contents significantly influence its performance in these applications.High-purity indium was prepared by combining zone refining with vacuum distillation.Results show that the average removal efficiency of impurity Sb can approach 95%,while the removal efficiency of impurities Sn and Bi can reach over 95%,and the removal efficiency of Si,Fe,Ni,and Pb can reach over 85%.Ultimately,the amount of Sn and Sb impurities is reduced to 2.0 and 4.1μg/kg,respectively,and that of most impurities,including Fe,Ni,Pb,and Bi,is reduced to levels below the instrumental detection limit.The average impurity removal efficiency is 90.9%,and the indium purity reaches 7N9. 展开更多
关键词 INDIUM HIGH-PURITY vacuum distillation zone refining
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Effect of Grain Refinement on Grain Boundary Diffusion Process and Magnetic Properties of Sintered NdFeB Magnets
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作者 Wang Mei Liu Weiming +8 位作者 Peng Buzhuang Wang Qian Wang Fei Zhang Yumeng Gu Xiaoqian Wang Qi Xiao Guiyong Liu Yan Zhu Xinde 《稀有金属材料与工程》 北大核心 2025年第11期2768-2776,共9页
Three types of NdFeB magnets with the same composition and different grain sizes were prepared,and then the grain boundary diffusion was conducted using metal Tb under the same technical parameters.The effect of grain... Three types of NdFeB magnets with the same composition and different grain sizes were prepared,and then the grain boundary diffusion was conducted using metal Tb under the same technical parameters.The effect of grain size on the grain boundary diffusion process and properties of sintered NdFeB magnets was investigated.The diffusion process was assessed using X-ray diffractometer,field emission scanning electron microscope,and electron probe microanalyzer.The magnetic properties of the magnet before and after diffusion were investigated.The results show that the grain refinement of the magnet leads to higher Tb utilization efficiency and results in higher coercivity at different temperatures.It can be attributed to the formation of a deeper and more complete core-shell structure,resulting in better magnetic isolation and higher anisotropy of the Nd_(2)Fe_(14)B grains.This work may shed light on developing high coercivity with low heavy rare earth elements through grain refinement. 展开更多
关键词 sintered NdFeB magnets grain refinement grain boundary diffusion COERCIVITY
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