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澳大利亚墨尔本皇家理工大学(RMIT)技术情报硕士学位课程设置 被引量:2
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作者 M.J.赖姆斯顿 李纲 《图书情报知识》 CSSCI 北大核心 1991年第3期49-52,共4页
本文是澳大利亚墨尔本皇家理工大学(RMIT)应用社会科学与传播学院院长M.J.赖姆斯顿向北京第二届情报学研究生教育国际研讨会(1991.3.27—31)提交的论文。现征得作者同意,并经作者亲自修改,由李纲译成中文,在本刊发表,供我国图书馆学情... 本文是澳大利亚墨尔本皇家理工大学(RMIT)应用社会科学与传播学院院长M.J.赖姆斯顿向北京第二届情报学研究生教育国际研讨会(1991.3.27—31)提交的论文。现征得作者同意,并经作者亲自修改,由李纲译成中文,在本刊发表,供我国图书馆学情报学专业研究生教育部门参考。发表时,文字略有删节。 展开更多
关键词 澳大利亚 情报学 教育 课程设置
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构筑可持续生物炭修饰钨酸铋复合光催化剂实现基于增强电荷转移效应的高效水净化
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作者 周恒 张蕊 +5 位作者 岳彩燕 吴旭 严琼 王昊 张衡 马天翼 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第4期169-184,共16页
近年来,全球环境问题日趋严峻,水体中的农药污染愈发严重,亟待解决.光催化作为一种绿色高效的技术,在环境修复领域具有较高的应用价值.然而,光生载流子的快速复合和电荷利用效率低是制约光催化效率的关键问题.生物炭(BC)是一种新兴的碳... 近年来,全球环境问题日趋严峻,水体中的农药污染愈发严重,亟待解决.光催化作为一种绿色高效的技术,在环境修复领域具有较高的应用价值.然而,光生载流子的快速复合和电荷利用效率低是制约光催化效率的关键问题.生物炭(BC)是一种新兴的碳质材料,来源于可持续利用的生物质废物,因其出色的吸附能力在污染物去除方面备受关注.因此,设计并开发功能化改性的BC基复合光催化剂,有望快速修复农药污染,推动高效、可持续的光催化污水净化技术的发展.本文首先以木屑生物质为原料,在厌氧条件下热解制备了不同氮含量掺杂的BC(Nx-BC,x代表尿素与BC的质量比).然后,以乙二醇为溶剂,将Nx-BC与Bi2WO6前驱体溶液混合,通过溶剂热反应制备一系列Bi2WO6/氮掺杂BC复合材料(BWO/Nx-BC),并用于可见光照射下光催化降解毒死蜱(CPs)农药.X射线衍射、扫描电镜、透射电镜和傅里叶红外光谱等结果表明,成功制备了BWO/Nx-BC复合材料.紫外-可见漫反射光谱结果表明,BWO/Nx-BC能有效吸收可见光,结合X射线光电子能谱分析,确定了其导带和价带位置.特别是,氮掺杂后的BWO/N3-BC在电子导电性提高的同时,还保持了良好的吸附性能,有效避免了光生载流子的重组.通过光致发光光谱、时间分辨光致发光光谱、光电流强度曲线和电化学阻抗曲线研究了光催化剂的载流子分离和重组行为.结果表明,BWO/N3-BC表现出较好的光催化降解效率,仅需0.5 h即可降解99.0%的CPs,其降解速率分别是纯BWO和纯N3-BC的2.91倍和12.13倍.BWO/N3-BC复合材料在8次循环使用后仍保持稳定.同时,考虑到真实水体环境的复杂性,本文还系统地探讨了不同操作参数对光催化降解活性的影响.自由基清除实验和电子顺磁共振结果表明,该反应的关键活性物质有•O_(2)^(-)、•OH和h^(+),其中•O_(2)^(-)是最主要的活性物质,并结合实验结果推测了BWO/N3-BC吸附-光降解的协同增效机制.利用高效液相色谱-质谱技术研究了CPs的降解中间体,提出了三种可能的降解途径,并对每种途径进行了详细分析.最后,通过生态毒性试验(大肠杆菌的培养)和毒性评估软件工具对CPs及其中间体的潜在生态毒性进行了系统评估.综上所述,本文通过直接煅烧辅助溶剂热法成功制备了BC基光催化剂,并揭示了其促进CPs光降解的机理,这为环境可持续的光催化循环经济提供了参考,也为光催化技术与废弃生物质高值利用相结合,实现环境修复开辟了新思路. 展开更多
关键词 光催化 生物炭 Bi_(2)WO_(6) 毒死蜱 毒性评价
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王尔义油画作品选登 被引量:1
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作者 王尔义 《安康学院学报》 2024年第2期F0003-F0003,共1页
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Influence of laser parameters on the microstructures and surface properties in laser surface modification of biomedical magnesium alloys
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作者 Chee Ying Tan Cuie Wen Hua Qian Ang 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第1期72-97,共26页
Biodegradable implants from magnesium(Mg)alloys have emerged in the biomedical field especially in the orthopedic and cardiovascular stent applications owing to their low density,high specific strength,excellent machi... Biodegradable implants from magnesium(Mg)alloys have emerged in the biomedical field especially in the orthopedic and cardiovascular stent applications owing to their low density,high specific strength,excellent machinability,good biocompatibility,and biodegradability.The primary shortcoming of Mg-based implants is their low corrosion resistance in the physiological environment,which results in premature mechanical integrity loss before adequate healing and the production of excessive hydrogen gas,which is harmful to the body tissues and negatively affects the biocompatibility of the implant.Laser surface modification has recently received attention because it can improve the surface properties such as surface chemistry,roughness,topography,corrosion resistance,wear resistance,hydrophilicity,and thus cell response to the surface of the material.The composition and microstructures including textures and phases of laser-treated surfaces depend largely on the laser processing parameters(input laser power,laser scan velocity,frequency,pulse duration,pressure,gas circulation,working time,spot size,beam focal position,and laser track overlap)and the thermophysical properties of the substrate(solubility,melting point,and boiling point).This review investigates the impacts of various laser surface modification techniques including laser surface melting,laser surface alloying,laser cladding,laser surface texturing,and laser shock peening,and highlights their significance in improving the surface properties of biodegradable Mg alloys for implant applications.Additionally,we explore how different laser process parameters affect its composition,microstructure,and surface properties in each laser surface modification technique. 展开更多
关键词 BIOCOMPATIBILITY BIODEGRADABILITY Corrosion Implant applications Laser surface modification Magnesium alloys
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Decade Milestone Advancement of Defect-Engineered g-C_(3)N_(4) for Solar Catalytic Applications 被引量:1
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作者 Shaoqi Hou Xiaochun Gao +8 位作者 Xingyue Lv Yilin Zhao Xitao Yin Ying Liu Juan Fang Xingxing Yu Xiaoguang Ma Tianyi Ma Dawei Su 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第4期153-218,共66页
Over the past decade, graphitic carbon nitride(g-C_(3)N_(4)) has emerged as a universal photocatalyst toward various sustainable carbo-neutral technologies. Despite solar applications discrepancy, g-C_(3)N_(4) is stil... Over the past decade, graphitic carbon nitride(g-C_(3)N_(4)) has emerged as a universal photocatalyst toward various sustainable carbo-neutral technologies. Despite solar applications discrepancy, g-C_(3)N_(4) is still confronted with a general fatal issue of insufficient supply of thermodynamically active photocarriers due to its inferior solar harvesting ability and sluggish charge transfer dynamics. Fortunately, this could be significantly alleviated by the “all-in-one” defect engineering strategy, which enables a simultaneous amelioration of both textural uniqueness and intrinsic electronic band structures. To this end, we have summarized an unprecedently comprehensive discussion on defect controls including the vacancy/non-metallic dopant creation with optimized electronic band structure and electronic density, metallic doping with ultraactive coordinated environment(M–N_(x), M–C_(2)N_(2), M–O bonding), functional group grafting with optimized band structure, and promoted crystallinity with extended conjugation π system with weakened interlayered van der Waals interaction. Among them, the defect states induced by various defect types such as N vacancy, P/S/halogen dopants, and cyano group in boosting solar harvesting and accelerating photocarrier transfer have also been emphasized. More importantly, the shallow defect traps identified by femtosecond transient absorption spectra(fs-TAS) have also been highlighted. It is believed that this review would pave the way for future readers with a unique insight into a more precise defective g-C_(3)N_(4) “customization”, motivating more profound thinking and flourishing research outputs on g-C_(3)N_(4)-based photocatalysis. 展开更多
关键词 Defect engineering g-C_(3)N_(4) Electronic band structures Photocarrier transfer kinetics Defect states
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Metabolic-associated fatty liver disease and sarcopenia:A double whammy 被引量:1
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作者 Aditya Viswanath Sherouk Fouda +1 位作者 Cornelius James Fernandez Joseph M Pappachan 《World Journal of Hepatology》 2024年第2期152-163,共12页
The prevalence of metabolic-associated fatty liver disease(MAFLD)has increased substantially in recent years because of the global obesity pandemic.MAFLD,now recognized as the number one cause of chronic liver disease... The prevalence of metabolic-associated fatty liver disease(MAFLD)has increased substantially in recent years because of the global obesity pandemic.MAFLD,now recognized as the number one cause of chronic liver disease in the world,not only increases liver-related morbidity and mortality among sufferers but also worsens the complications associated with other comorbid conditions such as cardiovascular disease,type 2 diabetes mellitus,obstructive sleep apnoea,lipid disorders and sarcopenia.Understanding the interplay between MAFLD and these comorbidities is important to design optimal therapeutic strategies.Sarcopenia can be either part of the disease process that results in MAFLD(e.g.,obesity or adiposity)or a consequence of MAFLD,especially in the advanced stages such as fibrosis and cirrhosis.Sarcopenia can also worsen MAFLD by reducing exercise capacity and by the production of various muscle-related chemical factors.Therefore,it is crucial to thoroughly understand how we deal with these diseases,especially when they coexist.We explore the pathobiological interlinks between MAFLD and sarcopenia in this comprehensive clinical update review article and propose evidence-based therapeutic strategies to enhance patient care. 展开更多
关键词 Metabolic-associated fatty liver disease SARCOPENIA Sarcopenic obesity Lean metabolic-associated fatty liver disease Cardiovascular disease Liver-muscle axis
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Impact of scandium and terbium on the mechanical properties,corrosion behavior,and biocompatibility of biodegradable Mg-Zn-Zr-Mn alloys
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作者 Khurram Munir Jixing Lin +3 位作者 Xian Tong Arne Biesiekierski Yuncang Li Cuie Wen 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第2期546-572,共27页
Magnesium(Mg)-based bone implants degrade rapidly in the physiological environment of the human body which affects their structural integrity and biocompatibility before adequate bone repair.Rare earth elements(REEs)h... Magnesium(Mg)-based bone implants degrade rapidly in the physiological environment of the human body which affects their structural integrity and biocompatibility before adequate bone repair.Rare earth elements(REEs)have demonstrated their effectiveness in tailoring the corrosion and mechanical behavior of Mg alloys.This study methodically investigated the impacts of scandium(Sc)and terbium(Tb)in tailoring the corrosion resistance,mechanical properties,and biocompatibility of Mg–0.5Zn–0.35Zr–0.15Mn(MZZM)alloys fabricated via casting and hot extrusion.Results indicate that addition of Sc and Tb improved the strength of MZZM alloys via grain size reduction and solid solution strengthening mechanisms.The extruded MZZM–(1–2)Sc–(1–2)Tb(wt.%)alloys exhibit compressive strengths within the range of 336–405 MPa,surpassing the minimum required strength of 200 MPa for bone implants by a significant margin.Potentiodynamic polarization tests revealed low corrosion rates of as–cast MZZM(0.25 mm/y),MZZM–2Tb(0.45 mm/y),MZZM–1Sc–1Tb(0.18 mm/y),and MZZM–1Sc–2Tb(0.64 mm/y),and extruded MZZM(0.17 mm/y),MZZM–1Sc(0.15 mm/y),MZZM-2Sc(0.45 mm/y),MZZM-1Tb(0.17 mm/y),MZZM-2Tb(0.10 mm/y),MZZM–1Sc-1Tb(0.14 mm/y),MZZM-1Sc-2Tb(0.40 mm/y),and MZZM–2Sc–2Tb(0.51 mm/y)alloys,which were found lower compared to corrosion rate of high-purity Mg(~1.0 mm/y)reported in the literature.Furthermore,addition of Sc,or Tb,or Sc and Tb to MZZM alloys did not adversely affect the viability of SaOS2 cells,but enhanced their initial cell attachment,proliferation,and spreading shown via polygonal shapes and filipodia.This study emphasizes the benefits of incorporating Sc and Tb elements in MZZM alloys,as they effectively enhance corrosion resistance,mechanical properties,and biocompatibility simultaneously. 展开更多
关键词 Corrosion property In vitro cytotoxicity Magnesium alloys Mechanical property Rare earth elements
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Layer chicken microbiota:a comprehensive analysis of spatial and temporal dynamics across all major gut sections
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作者 Yadav Sharma Bajagai Thi Thu Hao Van +3 位作者 Nitish Joat Kapil Chousalkar Robert J.Moore Dragana Stanley 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2024年第3期1056-1070,共15页
Background The gut microbiota influences chicken health,welfare,and productivity.A diverse and balanced microbiota has been associated with improved growth,efficient feed utilisation,a well-developed immune system,dis... Background The gut microbiota influences chicken health,welfare,and productivity.A diverse and balanced microbiota has been associated with improved growth,efficient feed utilisation,a well-developed immune system,disease resistance,and stress tolerance in chickens.Previous studies on chicken gut microbiota have predominantly focused on broiler chickens and have usually been limited to one or two sections of the digestive system,under con-trolled research environments,and often sampled at a single time point.To extend these studies,this investigation examined the microbiota of commercially raised layer chickens across all major gut sections of the digestive system and with regular sampling from rearing to the end of production at 80 weeks.The aim was to build a detailed picture of microbiota development across the entire digestive system of layer chickens and study spatial and temporal dynamics.Results The taxonomic composition of gut microbiota differed significantly between birds in the rearing and pro-duction stages,indicating a shift after laying onset.Similar microbiota compositions were observed between proven-triculus and gizzard,as well as between jejunum and ileum,likely due to their anatomical proximity.Lactobacil-lus dominated the upper gut in pullets and the lower gut in older birds.The oesophagus had a high proportion of Proteobacteria,including opportunistic pathogens such as Gallibacterium.Relative abundance of Gallibacterium increased after peak production in multiple gut sections.Aeriscardovia was enriched in the late-lay phase compared to younger birds in multiple gut sections.Age influenced microbial richness and diversity in different organs.The upper gut showed decreased diversity over time,possibly influenced by dietary changes,while the lower gut,specifi-cally cecum and colon,displayed increased richness as birds matured.However,age-related changes were inconsist-ent across all organs,suggesting the influence of organ-specific factors in microbiota maturation.Conclusion Addressing a gap in previous research,this study explored the microbiota across all major gut sections and tracked their dynamics from rearing to the end of the production cycle in commercially raised layer chickens.This study provides a comprehensive understanding of microbiota structure and development which help to develop targeted strategies to optimise gut health and overall productivity in poultry production. 展开更多
关键词 Chicken microbiota Gut microbiota Layers Spatial variation Temporal variation
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Application of multi-algorithm ensemble methods in high-dimensional and small-sample data of geotechnical engineering:A case study of swelling pressure of expansive soils
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作者 Chao Li Lei Wang +1 位作者 Jie Li Yang Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第5期1896-1917,共22页
Geotechnical engineering data are usually small-sample and high-dimensional,which brings a lot of challenges in predictive modeling.This paper uses a typical high-dimensional and small-sample swell pressure(P_(s))data... Geotechnical engineering data are usually small-sample and high-dimensional,which brings a lot of challenges in predictive modeling.This paper uses a typical high-dimensional and small-sample swell pressure(P_(s))dataset to explore the possibility of using multi-algorithm hybrid ensemble and dimensionality reduction methods to mitigate the uncertainty of soil parameter prediction.Based on six machine learning(ML)algorithms,the base learner pool is constructed,and four ensemble methods,Stacking(SG),Blending(BG),Voting regression(VR),and Feature weight linear stacking(FWL),are used for the multi-algorithm ensemble.Furthermore,the importance of permutation is used for feature dimensionality reduction to mitigate the impact of weakly correlated variables on predictive modeling.The results show that the proposed methods are superior to traditional prediction models and base ML models,where FWL is more suitable for modeling with small-sample datasets,and dimensionality reduction can simplify the data structure and reduce the adverse impact of the small-sample effect,which points the way to feature selection for predictive modeling.Based on the ensemble methods,the feature importance of the five primary factors affecting P_(s) is the maximum dry density(31.145%),clay fraction(15.876%),swell percent(15.289%),plasticity index(14%),and optimum moisture content(13.69%),the influence of input parameters on P_(s) is also investigated,in line with the findings of the existing literature. 展开更多
关键词 Expansive soils Swelling pressure Machine learning(ML) Multi-algorithm ensemble Sensitivity analysis
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Sandwich structures with tapered tubes as core:A quasi-static investigation
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作者 Xinmei Xiang Dehua Shao +5 位作者 Xin Zhang Umer Sharif Ngoc San Ha Li Xiang Jing Zhang Jiang Yi 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期447-462,共16页
In this article,the experimental and finite element analysis is utilized to investigate the quasi-static compression features of sandwich constructions built with tapered tubes.3D printing technology was utilized to c... In this article,the experimental and finite element analysis is utilized to investigate the quasi-static compression features of sandwich constructions built with tapered tubes.3D printing technology was utilized to create the hollow centers of the tapering tubes,with and without corrugations.The results demonstrate that the energy absorption(EA)and specific energy absorption(SEA)of the single corrugated tapered tube sandwich are 51.6% and 19.8% higher,respectively,than those of the conical tube sandwich.Furthermore,the results demonstrate that energy absorbers can benefit from corrugation in order to increase their efficiency.Additionally,the tapered corrugated tubes'resistance to oblique impacts was studied.Compared to a straight tube,the tapered tube is more resistant to oblique loads and has a lower initial peak crushing force(PCF),according to numerical simulations.After conducting a parametric study,it was discovered that the energy absorption performance of the sandwich construction is significantly affected by the amplitude,number of corrugations,and wall thickness.EA and SEA of DTS with corrugation number of 8 increased by 17.4%and 29.6%,respectively,while PCF decreased by 9.2% compared to DTS with corrugation number of 10. 展开更多
关键词 Sandwich structure Corrugated tube Tapered tube QUASI-STATIC Energy absorption
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An Optimized System of Random Forest Model by Global Harmony Search with Generalized Opposition-Based Learning for Forecasting TBM Advance Rate
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作者 Yingui Qiu Shuai Huang +3 位作者 Danial Jahed Armaghani Biswajeet Pradhan Annan Zhou Jian Zhou 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第3期2873-2897,共25页
As massive underground projects have become popular in dense urban cities,a problem has arisen:which model predicts the best for Tunnel Boring Machine(TBM)performance in these tunneling projects?However,performance le... As massive underground projects have become popular in dense urban cities,a problem has arisen:which model predicts the best for Tunnel Boring Machine(TBM)performance in these tunneling projects?However,performance level of TBMs in complex geological conditions is still a great challenge for practitioners and researchers.On the other hand,a reliable and accurate prediction of TBM performance is essential to planning an applicable tunnel construction schedule.The performance of TBM is very difficult to estimate due to various geotechnical and geological factors and machine specifications.The previously-proposed intelligent techniques in this field are mostly based on a single or base model with a low level of accuracy.Hence,this study aims to introduce a hybrid randomforest(RF)technique optimized by global harmony search with generalized oppositionbased learning(GOGHS)for forecasting TBM advance rate(AR).Optimizing the RF hyper-parameters in terms of,e.g.,tree number and maximum tree depth is the main objective of using the GOGHS-RF model.In the modelling of this study,a comprehensive databasewith themost influential parameters onTBMtogetherwithTBM AR were used as input and output variables,respectively.To examine the capability and power of the GOGHSRF model,three more hybrid models of particle swarm optimization-RF,genetic algorithm-RF and artificial bee colony-RF were also constructed to forecast TBM AR.Evaluation of the developed models was performed by calculating several performance indices,including determination coefficient(R2),root-mean-square-error(RMSE),and mean-absolute-percentage-error(MAPE).The results showed that theGOGHS-RF is a more accurate technique for estimatingTBMAR compared to the other applied models.The newly-developedGOGHS-RFmodel enjoyed R2=0.9937 and 0.9844,respectively,for train and test stages,which are higher than a pre-developed RF.Also,the importance of the input parameters was interpreted through the SHapley Additive exPlanations(SHAP)method,and it was found that thrust force per cutter is the most important variable on TBMAR.The GOGHS-RF model can be used in mechanized tunnel projects for predicting and checking performance. 展开更多
关键词 Tunnel boring machine random forest GOGHS optimization PSO optimization GA optimization ABC optimization SHAP
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Lamellar water induced quantized interlayer spacing of nanochannels walls
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作者 Yue Zhang Chenlu Wang +3 位作者 Chunlei Wang Yingyan Zhang Junhua Zhao Ning Wei 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第2期356-365,共10页
The nanoscale confinement is of great important for the industrial applications of molecular sieve,desalination,and also essential in bio-logical transport systems.Massive efforts have been devoted to the influence of... The nanoscale confinement is of great important for the industrial applications of molecular sieve,desalination,and also essential in bio-logical transport systems.Massive efforts have been devoted to the influence of restricted spaces on the properties of confined fluids.However,the situation of channel-wall is crucial but attracts less attention and remains unknown.To fundamentally understand the mechanism of channel-walls in nanoconfinement,we investigated the interaction between the counter-force of the liquid and interlamellar spacing of nanochannel walls by considering the effect of both spatial confinement and surface wettability.The results reveal that the nanochannel stables at only a few discrete spacing states when its confinement is within 1.4 nm.The quantized interlayer spacing is attributed to water molecules becoming laminated structures,and the stable states are corresponding to the monolayer,bilayer and trilayer water configurations,respectively.The results can potentially help to understand the characterized interlayers spacing of graphene oxide membrane in water.Our findings are hold great promise in design of ion filtration membrane and artificial water/ion channels. 展开更多
关键词 NANOCONFINEMENT Quantized spacing Lamellar water layer MD simulations Entropy force
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Enhancing Green Ammonia Electrosynthesis Through Tuning Sn Vacancies in Sn‑Based MXene/ MAX Hybrids
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作者 Xinyu Dai Zhen‑Yi Du +10 位作者 Ying Sun Ping Chen Xiaoguang Duan Junjun Zhang Hui Li Yang Fu Baohua Jia Lei Zhang Wenhui Fang Jieshan Qiu Tianyi Ma 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第5期154-168,共15页
Renewable energy driven N_(2) electroreduction with air as nitrogen source holds great promise for realizing scalable green ammonia production.However,relevant out-lab research is still in its infancy.Herein,a novel S... Renewable energy driven N_(2) electroreduction with air as nitrogen source holds great promise for realizing scalable green ammonia production.However,relevant out-lab research is still in its infancy.Herein,a novel Sn-based MXene/MAX hybrid with abundant Sn vacancies,Sn@Ti_(2)CTX/Ti_(2)SnC–V,was synthesized by controlled etching Sn@Ti_(2)SnC MAX phase and demonstrated as an efficient electrocatalyst for electrocatalytic N2 reduction.Due to the synergistic effect of MXene/MAX heterostructure,the existence of Sn vacancies and the highly dispersed Sn active sites,the obtained Sn@Ti2CTX/Ti_(2)SnC–V exhibits an optimal NH_(3) yield of 28.4μg h^(−1) mg_(cat)^(−1) with an excellent FE of 15.57% at−0.4 V versus reversible hydrogen electrode in 0.1 M Na_(2)SO_(4),as well as an ultra-long durability.Noticeably,this catalyst represents a satisfactory NH3 yield rate of 10.53μg h^(−1) mg^(−1) in the home-made simulation device,where commercial electrochemical photovoltaic cell was employed as power source,air and ultrapure water as feed stock.The as-proposed strategy represents great potential toward ammonia production in terms of financial cost according to the systematic technical economic analysis.This work is of significance for large-scale green ammonia production. 展开更多
关键词 Green ammonia synthesis N2 electroreduction Renewable energy SN MXene/MAX hybrid
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液氢中固空枝晶生长凝固定量相场法研究 被引量:1
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作者 李超龙 文键 +3 位作者 王磊 厉彦忠 雷刚 屠基元 《西安交通大学学报》 EI CAS CSCD 北大核心 2023年第5期128-135,共8页
为探究固空形成过程中枝晶微结构演化和氧溶质非均匀分布规律,建立了描述固空枝晶生长凝固过程中枝晶形态演化和氧溶质分布的定量相场模型(QPFM),应用该模型对连续冷却条件下的固空单枝晶和多枝晶生长行为特性进行了研究,选择了两条特... 为探究固空形成过程中枝晶微结构演化和氧溶质非均匀分布规律,建立了描述固空枝晶生长凝固过程中枝晶形态演化和氧溶质分布的定量相场模型(QPFM),应用该模型对连续冷却条件下的固空单枝晶和多枝晶生长行为特性进行了研究,选择了两条特殊位置曲线定量表述氧溶质分布规律。结果表明:枝晶形态随初始过冷度增大而变得复杂,二次枝晶臂更为发达;氧溶质质量分数呈现枝晶内部贫氧外部富氧的分布特征,沿一次枝晶臂和二次枝晶臂的轴线形成了氧溶质质量分数较低的脊柱;多枝晶的相互作用破环了枝晶的对称形态;连续冷却条件下,固空枝晶二次枝晶臂随时间增长逐渐粗化、融合,固相率和最大氧溶质质量分数分别持续增长到最大值0.9111和0.8406;枝晶之间的间隙阻碍了氧溶质的扩散,使得氧溶质质量分数由单枝晶时的0.402升至多枝晶时的0.668。研究可为液氢系统的安全使用提供理论指导。 展开更多
关键词 固空枝晶 定量相场法 氧溶质分布 形态演化
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三维非饱和土边坡拟动力稳定性分析初探
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作者 王龙 陈国兴 +3 位作者 胡伟 孙德安 李洁 刘文化 《岩土工程学报》 EI CAS CSCD 北大核心 2023年第9期1859-1867,共9页
边坡在地震作用下极易失稳破坏且通常伴随明显的三维破坏特征,增加边坡阶数并结合抗滑桩等加固措施可有效提高边坡的动稳定性,广泛用于滑坡灾害防治中。基于极限分析上限原理并结合拟动力法,将塑性变形理论扩展至非饱和土中,改进已提出... 边坡在地震作用下极易失稳破坏且通常伴随明显的三维破坏特征,增加边坡阶数并结合抗滑桩等加固措施可有效提高边坡的动稳定性,广泛用于滑坡灾害防治中。基于极限分析上限原理并结合拟动力法,将塑性变形理论扩展至非饱和土中,改进已提出的半解析水平片分法,计算具有非线性分布特征的非饱和土重力、地震惯性力和抗滑桩侧阻力所做外功率和表观黏聚力的功率耗散率,与解析解对比,验证了该方法的合理性。通过算例分析,探究了非饱和土边坡的地震响应规律,揭示了吸力对边坡地震稳定性及抗滑桩加固效果的强化作用。结果表明:吸力对边坡稳定性的贡献可达15%~30%,且与地震动特性密切相关,地震波达到峰值时,吸力效应得到显著加强;水平加速度系数和土体剪切模量对边坡地震稳定性影响较大;地震作用下边坡将出现明显的“浅层”滑动现象。 展开更多
关键词 非饱和土边坡 极限分析 拟动力法 基质吸力 三维效应
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固空枝晶微结构生长演化非等温定量相场模拟研究
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作者 李超龙 文键 +3 位作者 王磊 雷刚 陈强 屠基元 《西安交通大学学报》 EI CAS CSCD 北大核心 2023年第8期46-54,共9页
为了探究热-溶质耦合驱动下固空枝晶生长演化和氧溶质分布规律,建立了非等温定量相场模型,应用该模型研究了不同过冷度及边界热流条件下固空枝晶的形态演化、生长速度、氧溶质分布。结果表明:相比等温模拟,考虑凝固潜热的非等温模拟可... 为了探究热-溶质耦合驱动下固空枝晶生长演化和氧溶质分布规律,建立了非等温定量相场模型,应用该模型研究了不同过冷度及边界热流条件下固空枝晶的形态演化、生长速度、氧溶质分布。结果表明:相比等温模拟,考虑凝固潜热的非等温模拟可以更真实再现固空枝晶的生长过程,氧质量分数峰值相比等温模拟减少了8.5%~14.6%;枝晶的生长速度、最大氧质量分数和初始过冷度呈现正相关性,初始过冷度为4 K时,固液糊状区氧质量分数最大可达到0.401;边界热流的存在可显著改变计算域温度分布进而影响固空枝晶的生长模式;热输入减缓了枝晶的生长,而热提取使枝晶臂生长得更为繁盛粗壮,热提取、热输入条件下的固相率分别是无边界热流时的138%、69%,最大氧质量分数分别是无边界热流时的146%、94%。该研究可增进对液氢中固空枝晶生长行为的理解,为液氢系统的安全使用提供一定的理论指导。 展开更多
关键词 固空枝晶 非等温相场 形态演化 液氢
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Microstructures, mechanical properties, corrosion, and biocompatibility of extruded Mg-Zr-Sr-Ho alloys for biodegradable implant applications 被引量:2
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作者 Faisal Kiani Jixing Lin +3 位作者 Alireza Vahid Khurram Munir Cuie Wen Yuncang Li 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第1期110-136,共27页
In this study,the microstructures,mechanical properties,corrosion behaviors,and biocompatibility of extruded magnesium-zirconiumstrontium-holmium(Mg-Zr-Sr-Ho)alloys were comprehensively investigated.The effect of diff... In this study,the microstructures,mechanical properties,corrosion behaviors,and biocompatibility of extruded magnesium-zirconiumstrontium-holmium(Mg-Zr-Sr-Ho)alloys were comprehensively investigated.The effect of different concentrations of Ho on the microstructural characteristics,tensile and compressive properties,corrosion resistance,and biocompatibility were investigated.The microstructures of the extruded Mg-1Zr-0.5Sr-xHo(x=0.5,1.5,and 4 wt.%)alloys consisted ofα-Mg matrix,fineα-Zr particles,and intermetallic phase particles of Mg_(17)Sr_(2) and Ho_(2)Mg mainly distributed at the grain boundaries.Extensive{1012}tensile twins were observed in the partially recrystallized samples of Mg-1Zr-0.5Sr-0.5Ho and Mg-1Zr-0.5Sr-1.5Ho.Further addition of Ho to 4 wt.%resulted in a complete recrystallization due to activation of the particle stimulated nucleation around the Mg_(17)Sr_(2) particles.The evolution of a rare earth(RE)texture was observed with the Ho addition,which resulted in the weakened basal and prismatic textures.Furthermore,a drastic increase of 200%in tensile elongation and 89%in compressive strain was observed with Ho addition increased from 0.5 to 4 wt%,respectively.The tension-compression yield asymmetry was significantly decreased from 0.62 for Mg-1Zr-0.5Sr-0.5Ho to 0.98 for Mg-1Zr-0.5Sr-4Ho due to the weakening of textures.Corrosion analysis of the extruded Mg-Zr-Sr-Ho alloys revealed the presence of pitting corrosion.A minimum corrosion rate of 4.98 mm y^(−1) was observed in Mg-1Zr-0.5Sr-0.5Ho alloy.The enhanced corrosion resistance is observed due to the presence of Ho_(2)O_(3) in the surface film which reduced galvanic effect.The formation of a stabilized surface film due to the Ho_(2)O_(3) was confirmed through the electrical impedance spectroscopy and XPS analysis.An in vitro cytotoxicity assessment revealed good biocompatibility and cell adhesion in relation to SaOS2 cells. 展开更多
关键词 Mg-Zr-Sr-Ho alloy Mechanical properties CORROSION Cytotoxicity EBSD Electrical impedance spectroscopy Potentiodynamic polarization
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Enhancing Iterative Learning Control With Fractional Power Update Law 被引量:1
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作者 Zihan Li Dong Shen Xinghuo Yu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2023年第5期1137-1149,共13页
The P-type update law has been the mainstream technique used in iterative learning control(ILC)systems,which resembles linear feedback control with asymptotical convergence.In recent years,finite-time control strategi... The P-type update law has been the mainstream technique used in iterative learning control(ILC)systems,which resembles linear feedback control with asymptotical convergence.In recent years,finite-time control strategies such as terminal sliding mode control have been shown to be effective in ramping up convergence speed by introducing fractional power with feedback.In this paper,we show that such mechanism can equally ramp up the learning speed in ILC systems.We first propose a fractional power update rule for ILC of single-input-single-output linear systems.A nonlinear error dynamics is constructed along the iteration axis to illustrate the evolutionary converging process.Using the nonlinear mapping approach,fast convergence towards the limit cycles of tracking errors inherently existing in ILC systems is proven.The limit cycles are shown to be tunable to determine the steady states.Numerical simulations are provided to verify the theoretical results. 展开更多
关键词 Asymptotic convergence convergence rate finiteiteration tracking fractional power learning rule limit cycles
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河流动床阻力影响参数分析及其计算研究
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作者 李琳琪 张红武 +1 位作者 侯琳 李浩博 《水利学报》 EI CSCD 北大核心 2023年第12期1496-1506,共11页
动床阻力计算对河流研究和工程问题解决十分重要。自20世纪中叶起利用现代水力学知识计算动床阻力的方法陆续出现,本文对现有成果进行了分析评述,并对经典的Einstein和钱宁等阻力计算方法进行剖析,发现基于水力半径分割假说建立的动床... 动床阻力计算对河流研究和工程问题解决十分重要。自20世纪中叶起利用现代水力学知识计算动床阻力的方法陆续出现,本文对现有成果进行了分析评述,并对经典的Einstein和钱宁等阻力计算方法进行剖析,发现基于水力半径分割假说建立的动床阻力算法,不适用于研究主要由悬移质输沙强度决定床面形态的水流阻力问题。为此,本文首先选取有代表性的基本物理量,同实测糙率值进行相关性分析,确定出主参数;通过数据分析确定水深和能坡的指数后,运用造床流量下床沙中值粒径公式计算河床比降;基于能坡I计算需体现河床比降主导影响的同时应考虑边岸局部水头损失作用的认识,给出能坡修正式,再引入能体现沙粒和含沙量对动床摩阻的影响的因子,建立了动床阻力计算新方法。大量实测资料验证结果表明,本文公式计算精度高,适用性强。 展开更多
关键词 动床阻力 糙率 冲积河流 黄河 能坡
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Management of metabolic-associated fatty liver disease: The diabetology perspective 被引量:3
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作者 Mohammad Sadiq Jeeyavudeen Shahanas K A Khan +1 位作者 Sherouk Fouda Joseph M Pappachan 《World Journal of Gastroenterology》 SCIE CAS 2023年第1期126-143,共18页
The metabolic syndrome as a consequence of the obesity pandemic resulted in a substantial increase in the prevalence of metabolic-associated fatty live disease(MAFLD)and type 2 diabetes mellitus(T2DM).Because of the s... The metabolic syndrome as a consequence of the obesity pandemic resulted in a substantial increase in the prevalence of metabolic-associated fatty live disease(MAFLD)and type 2 diabetes mellitus(T2DM).Because of the similarity in pathobiology shared between T2DM and MAFLD,both disorders coexist in many patients and may potentiate the disease-related outcomes with rapid progression and increased complications of the individual diseases.In fact,awareness about this coexistence and the risk of complications are often overlooked by both hepatologists and diabetologists.Management of these individual disorders in a patient should be addressed wholistically using an appropriate multidisciplinary team approach involving both the specialists and,when necessary,liaising with dieticians and surgeons.This comprehensive review is to compile the current evidence from a diabetologist's perspective on MAFLD and T2DM and to suggest optimal management strategies. 展开更多
关键词 Metabolic syndrome Metabolic-associated fatty liver disease Type 2 diabetes mellitus Nonalcoholic fatty liver disease Nonalcoholic steatohepatitis Diabetology perspective OBESITY
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