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Tribological and vibrational characteristics of AISI 316L tested at elevated temperature and 600 Torr vacuum

Defence Technology（防务技术） 2019年第1期15卷 58-64页

作者： k.Arul Raj M.p.Arunkumar p.k.c.kanigalpula M.karthikeyan Department of Mechanical Engineering Koneru Lakshmaiah Education Foundation Department of Mechanical Engineering RajaRajeswari College of Engineering

Friction and wear studies enable the investigation of material interaction between two sliding surfaces in contact. In the present investigation, the coefficient of friction and the wear resistance of AISI 316 L parts were studied under self-mating, dry sliding conditions using a pin-on-disc type configuration. The experiments were conducted at vacuum based high temperature pin-on-disc tribometer. The 4 mm diameter pin and 180 mm diameter disc were subjected to varying sliding velocities(0.5, 0.75 and 1.5 m/s) and were operated in 200, 400, 500 and 580 ℃ temperature at 600 Torr vacuum. The variation of specific wear rates with sliding velocities and different environmental conditions was studied. The morphology of sliding/rubbed surfaces was observed using Scanning Electron Microscope. In summary, it was found that a severe to mild wear transition occurred in sliding under operating conditions. Increased wear rates have been observed for 500 and 580 ℃ with increasing sliding velocity. Adhesive wear has been found to be predominant at 500 and 580 ℃ where as de-lamination has been observed at ambient temperature,200 and 400 ℃ in vacuum. The present paper also carried out the numerical analysis of the vibration behavior of AISI 316 L under thermal environment. Results revealed that at high temperature vibrational amplitude and natural frequency is significantly reduced. This can be attributed to the reduction in stiffness of the material at elevated temperatures. This high amplitude vibration during service can lead to high wear rate.

关键词： pin-on-disc Sliding wear Vacuum De-lamination Scanning electron microscope Vibration

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电子束焊接析出硬化cucrZr合金:模拟与实验

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Transactions of Nonferrous Metals Society of china 2020年第8期30卷 2156-2169页

作者： Rajveer SINGH Sachin SINGH p.k.c.kanigalpula J.S.SAINI Department of Mechanical Engineering Thapar Institute of Engineering and TechnologyPatiala-147004PunjabIndia

为了在焊接析出硬化铜铬锆(pH-cucrZr)合金时保持结构的一致性,采用电子束焊接(EBW)工艺。对pH-cucrZr合金零件的EBW过程进行实验研究和数值模拟,建立三维有限元模型,以预测输出响应(焊道熔透和焊道宽度)与EBW输入参数(电子束电流、加... 详细信息

为了在焊接析出硬化铜铬锆(pH-cucrZr)合金时保持结构的一致性,采用电子束焊接(EBW)工艺。对pH-cucrZr合金零件的EBW过程进行实验研究和数值模拟,建立三维有限元模型,以预测输出响应(焊道熔透和焊道宽度)与EBW输入参数(电子束电流、加速电压和焊接速度)之间的函数关系。采用一种具有高斯热分布的圆形、园锥形复合热源模拟EBW过程的深熔焊特性。在Ansys软件中开发用户自定义函数,进行数值模拟。将数值模拟结果与实验结果进行比较,两者吻合较好。所建模型可用于EBW过程中广泛涉及复杂几何形状问题的参数研究。输入电流是对焊道熔透和焊道宽度影响最大的输入参数,其贡献率分别为44.56%和81.13%。

关键词：电子束焊接焊道宽度焊道熔透模拟铜铬锆合金

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Efficient guiding and focusing of intense laser pulse using periodic thin slits

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Matter and Radiation at Extremes 2024年第4期9卷 29-39页

作者： L.Xu T.W.Huang k.Jiang c.N.Wu H.peng p.c.hen R.Li H.B.Zhuo c.T.Zhou Shenzhen key Laboratory of Ultraintense Laser and Advanced Material Technology Center for Intense Laser ApplicationTechnologyand College of Engineering PhysicsShenzhen Technology UniversityShenzhen 518118People’s Republic of China

Slits have been widely used in laser-plasma interactions as plasma optical components for generating high-harmonic light and controlling laser-driven particle ***,we propose and demonstrate that periodic thin slits can be regarded as a new breed of optical elements for efficient focusing and guiding of intense laser *** fundamental physics of intense laser interaction with thin slits is studied,and it is revealed that relativistic effects can lead to enhanced laser focusing far beyond the pure diffractive focusing *** addition,the interaction of an intense laser pulse with periodic thin slits makes it feasible to achieve multifold enhancement in both laser intensity and energy transfer efficiency compared with conventional *** results provide a novel method for manipulating ultra-intense laser pulses and should be of interest for many laser-based applications.

关键词： laser pulse intense

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Effect of Moringa oleifera on semen quality profiles in endangered Teressa goat under tropical humid island ecosystem

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Asian pacific Journal of Reproduction 2024年第2期13卷 89-96页

作者： p.perumal Jai Sunder A.k.De A.k.Nahak D.k.chaurasia T.c.Balamurugan D.Bhattacharya IcAR-central Island Agricultural Research Institute Port Blair-744105Andaman and Nicobar IslandsIndia OUAT-college of Veterinary Science and Animal Husbandry Bhubaneswar-751003OdishaIndia TANUVAS-Veterinary college and Research Institute Salem-636112Tamil NaduIndia

Objective:To investigate the effect of Moringa oleifera leaf extract on semen quality parameters in Teressa goat ***:A total of 25 semen samples from six bucks were selected for the *** of 150×10^(6) were incubated in 0,300,500 and 700μg of leaf extract as groupⅠ,Ⅱ,Ⅲ and Ⅳ,*** stored semen samples were analysed for motility,viability,total sperm abnormalities,plasma membrane,acrosomal and nuclear integrities,seminal plasma intracellular enzymes[aspartate aminotransferase(AST),alanine aminotransferase(ALT)and lactate dehydrogenase(LDH)]and total antioxidant capacity(TAc)and spermatozoa malondialdehyde(MDA)and cholesterol efflux in comparison with the control group(groupⅠ)for up to 72 ***:Moringa oleifera leaf extract(500μg/150×10^(6) spermatozoa)-treated semen had significantly higher motility,viability,plasma membrane,acrosomal and nuclear integrities,and TAc(pcantly lower total sperm abnormalities,AST,ALT,LDH,MDA production and cholesterol efflux compared to those in other Moringa oleifera leaf extract treated(300 or 700μg/150×10^(6) spermatozoa)and control groups at different hours of liquid storage(pparameters and TAc showed an increasing trend and total sperm abnormalities,MDA production,leakage of intra-cellular enzymes and cholesterol efflux showed a decreasing trend from group Ⅰto group Ⅲand then an opposite trend from group Ⅲ to group Ⅳ at different hours of liquid ***:Moringa oleifera leaf extract 500μg/150×10^(6) spermatozoa can be used for liquid semen preservation in Teressa goat at Andaman and Nicobar Islands.

关键词： Moringa oleifera Semen Teressa goat Andaman and Nicobar Islands

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Near resonance vibration isolation on a levered-dual response(LEDAR)coulomb-damped system by differential preloads/offsets in linear springs

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1033-1050页

作者： T.I.TOLUWALOJU c.k.THEIN D.HALIM Department of Mechanical Materials and Manufacturing EngineeringUniversity of Nottingham Ningbo ChinaNingbo 315100Zhejiang ProvinceChina Nottingham Ningbo china Beacons of Excellence Research and Innovation Institute University of Nottingham Ningbo ChinaNingbo 315048Zhejiang ProvinceChina

The levered-dual response(LEDAR)coulomb-damped system attains near resonant vibration isolation by differential preloads/offsets in linear *** takes the advantages of both the preloads/offsets in linear springs and the guiderail friction for realizing different levels of vibration *** isolation capacities are investigated on the strategies with both the horizontal and vertical guiderails,with the horizontal rail only,and without *** compressive preloads generally result in the consumption of most of the initial excitation energy so as to overcome the potential *** isolation onsets at the frequency ratio of 1∓0.095 on the left-hand side(LHS)and the right-hand side(RHS)of the lever are relative to the load plate *** observed near resonant isolation thus makes the LEDAR system a candidate for the isolation of the mechanical systems about resonance while opening a path for simultaneous harvesterisolation functions and passive functions at extreme frequencies.

关键词： lever ratio coulomb damping preload tension/compression isolation band/depth offset potential

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Direct-Seeded Rice: Genetic Improvement of Game-changing Traits for Better Adaption

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Rice science 2024年第4期31卷 417-433页

作者： priyanka NEGI Jagadish RANE Rajendra Sadashiv WAGH Tukaram Jayaram BHOR Dipti Digambar GODSE priyanka JADHAV c.ANILkUMAR Dasari SREEkANTH k.SAMMI REDDY Sharad Ramrao GADAkH k.M.BORAIH c.B.HARISHA p.S.BASAVARAJ Indian council of Agricultural Research(IcAR)-National Institute of Abiotic Stress Management Baramati 413115India Mahatma phule krishi Vidyapeeth Rahuri 413722India IcAR-central Institute for Arid Horticulture Bikaner 334006India IcAR-National Rice Research Institute Cuttack 753006India IcAR-Directorate of Weed Research Jabalpur 482004India Dr.panjabrao Deshmukh krishi Vidyapeeth Akola 444104India

The sustainability of rice production continues to be a subject of uncertainty and inquiry attributed to shifts in climatic conditions. In light of the impending climate change crisis and the high labor and water costs accompanying it, direct-seeded rice(DSR) is unquestionably one of the most practical solutions. Despite its resource and climate-friendly advantages, early maturing rice faces weed competitiveness and seedling establishment challenges. Resolving these issues is crucial for promoting its wider adoption among farmers, presenting it as a more effective sustainable rice cultivation method globally. Diverse traditional and contemporary breeding methods are employed to mitigate the limitations of the DSR approach, leveraging advanced techniques such as speed breeding and genome editing. Focusing on key traits like mesocotyl length elongation, early seedling vigor, root system architecture, and weed competitiveness holds promise for transformative improvements in DSR adaptation at a broader scale within farming communities. This review aims to summarize how these features contribute to increased crop production in DSR conditions and explore the research efforts focusing on enhancing DSR adaptation through these traits. Emphasizing the pivotal role of these game-changing traits in DSR adaptation, our analysis sheds light on their potential transformative impact and offers valuable insights for advancing DSR practices.

关键词： climate change direct-seeded rice aerobic rice early vigor trait

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Drought events influence nutrient canopy exchanges and green leaf partitioning during senescence in a deciduous forest

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Forest Ecosystems 2024年第1期11卷 110-119页

作者： J.Touche c.calvaruso p.De Donato M.-p.Turpault INRAE BEFF-54000NancyFrance UMR 7359 GeoRessourcesFaculte des Sciences-Campus des Aiguillettes54506Vandoeuvre Les NancyFrance EcoSustain Environmental Engineering OfficeResearch and DevelopmentKanfen57330France

The increase in the frequency and intensity of drought events expected in the coming decades in Western Europe may disturb forest biogeochemical cycles and create nutrient deficiencies in *** possible origin of nutrient deficiency is the disturbance of the partitioning of the green leaf pool during the leaf senescence period between resorption,foliar leaching and senesced ***,the effects of drought events on this partitioning and the consequences for the maintenance of tree nutrition are poorly *** experiment in a beech forest in Meuse(France)was conducted to assess the effect of drought events on nutrient canopy exchanges and on the partitioning of the green leaf pool during the leaf senescence *** aim was to identify potential nutritional consequences of droughts for *** nutrient dynamics,including resorption,chemistry of green and senesced leaves,foliar absorption and leaching in mature beech stands from 2012 to 2019 allowed us to compare the nutrient exchanges for three nondry and three dry years(i.e.,with an intense drought event during the growing season).During dry years,we observed a decrease by almost a third of the potassium(k)partitioning to resorption(*** efficiency),thus reducing the k reserve in trees for the next growing *** result suggests that with the increased drought frequency and intensity expected for the coming decades,there will be a risk of potassium deficiency in trees,as already observed in a rainfall exclusion experiment on the same study *** foliar leaching and higher parititioning to the senesced leaves for k and phosphorus(p)were also *** addition,a slight increase in nitrogen(N)resorption efficiency occurred during dry years which is more likely to improve tree *** calcium(ca)negative resorption decreased,with no apparent consequence in our study *** results show that nutrient exchanges in the canopy and the partitioning of the green leaf

关键词： Natural drought Beech forest canopy Resorption Foliar leaching Senesced leaves Nutrition

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HI in High Gas-phase Metallicity Dwarf Galaxy WISEA J230615.06+143927.9

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Research in Astronomy and Astrophysics 2024年第1期24卷 292-299页

作者： Yan Guo c.Sengupta T.c.Scott p.Lagos Y.Luo purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China Institute of Astrophysics and Space Sciences(IA porto) Rua das Estrelas4150-762PortoPortugal

We present resolved Giant Metrewave Radio Telescope H I observations of the high gas-phase metallicity dwarf galaxy WISEA J230615.06+143927.9(z = 0.005)(hereafter J2306) and investigate whether it could be a Tidal Dwarf Galaxy(TDG) candidate. TDGs are observed to have higher metallicities than normal dwarfs. J2306 has an unusual combination of a blue g-r color of 0.23 mag, irregular optical morphology and high-metallicity(12 +log(O/H) = 8.68 ± 0.14), making it an interesting galaxy to study in more detail. We find J2306 to be an H I rich galaxy with a large extended, unperturbed rotating H I disk. Using our H I data we estimated its dynamical mass and found the galaxy to be dark matter(DM) dominated within its H I radius. The quantity of DM, inferred from its dynamical mass, appears to rule out J2306 as an evolved TDG. A wide area environment search reveals J2306 to be isolated from any larger galaxies which could have been the source of its high gas metallicity. Additionally, the H I morphology and kinematics of the galaxy show no indication of a recent merger to explain the *** detailed optical spectroscopic observations of J2306 might provide an answer to how a seemingly ordinary irregular dwarf galaxy achieved such a high level of metal enrichment.

关键词： galaxies:abundances galaxies:dwarf galaxies:irregular radio lines:galaxies radio lines:ISM

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Single atom cu-N-c catalysts for the electro-reduction of cO_(2) to cO assessed by rotating ring-disc electrode

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Journal of Energy chemistry 2024年第1期88卷 169-182,I0004页

作者： S.pérez-Rodríguez M.Gutiérrez-Roa c.Giménez-Rubio D.Ríos-Ruiz p.Arévalo-cid M.V.Martínez-Huerta A.Zitolo M.J.Lázaro D.Sebastián Instituto de carboquímica(cSIc) Miguel Luesma Castán 450018 ZaragozaSpain Instituto de catálisis y petroleoquímica(cSIc) Marie Curie 228049 MadridSpain Synchrotron SOLEIL L’Orme des MerisiersDépartementale 12891190France

The electrochemical cO_(2) reduction reaction(cO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(cu-N-c) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient cO_(2)RR. The electrocatalytic performance of cu-N-c materials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for cO_(2)RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized cu-Nc catalysts are found to be active and highly cO selective at low overpotentials(from -0.6 to -0.8 V ***) in 0.1 M kHcO_(3), while H_(2) from the competitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing cu-N_(4) moieties exhibits a cO_(2)-to-cO turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/cO ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from cO_(2)RR.

关键词： cu-N-c carbon xerogel Rotating ring disc electrode carbon dioxide reduction reaction carbon monoxide

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Bile acid signaling in the regulation of whole body metabolic and immunological homeostasis

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Science china(Life Sciences) 2024年第5期67卷 865-878页

作者： Wei Jia Yitao Li kenneth c.p.cheung Xiaojiao Zheng School of chinese Medicine Hong Kong Baptist UniversityHong KongChina center for Translational Medicine and Shanghai key Laboratory of Diabetes Mellitus Shanghai Sixth People's Hospital Affiliated to Shanghai JiaoTong University School of MedicineShanghai 200233China

Bile acids(BAs)play a crucial role in nutrient absorption and act as key regulators of lipid and glucose metabolism and immune *** the enterohepatic circulation,BAs are synthesized,metabolized,and reabsorbed,with a portion entering the vascular circulation and distributing *** allows BAs to interact with receptors in all major organs,leading to organ-organ interactions that regulate both local and global metabolic processes,as well as the immune *** review focuses on the whole-body effects of BA-mediated metabolic and immunological regulation,including in the brain,heart,liver,intestine,eyes,skin,adipose tissue,and *** BA synthesis and receptor signaling is a promising strategy for the development of novel therapies for various diseases throughout the body.

关键词： bile acid whole body metabolism immunity

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