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Improvement of Surface mechanical and Tribological Characteristics of L-PBF Processed Commercially Pure Titanium through Ultrasonic Impact Treatment

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Acta metallurgica Sinica(English Letters) 2024年第6期37卷 1034-1046页

作者： iman Ansarian Reza Taghiabadi Saeid Amini mohammad Hossein mosallanejad Luca Iuliano Abdollah Saboori Department of materials Science and metallurgy Imam Khomeini International University(IKIU)QazvinIran Department of mechanical Engineering University of KashanKashanIran Integrated additive manufacturing Center Department of Management and Production EngineeringPolitecnico di TorinoCorso Duca Degli Abruzzi 2410129TurinItaly

multi-pass ultrasonic impact treatment(UIT)was applied to modify the microstructure and improve the mechanical and tribological characteristics at the near-surface region of commercially pure Ti(CP-Ti)specimens produced by the laser powder bed fusion(L-PBF)*** considerably refined the L-PBF process-related acicular martensites(α′-m)and produced a well-homogenized and dense surface microstructure,where the porosity content of 1-,3-,and 5-pass UITed samples was reduced by 43,60,and 67%,*** UITed samples showed an enhancement in their near-surface mechanical properties up to a depth of about 300μ*** nanoindentation results for the 3-pass UITed sample revealed an increase of about 53,45,and 220%in its nanohardness,H/E_(r),and H_(3)/E_(r)^(2)indices,*** stylus profilometry results showed that performing the UIT removed the L-PBF-related features/defects and offered a smooth *** roughness average(R_(a))and the skewness(R_(sk))of the 3-pass UITed sample were found to be lower than those of the L-PBFed sample by 95 and 223%,*** the UIT also enhanced the material ratio,where the maximum load-bearing capacity(~100%)in as-L-PBFed(as-built)and 3-pass UITed samples was obtained at 60-and 10-µm depths,*** tribological investigations showed that applying the UIT resulted in a significant reduction of wear rate and average coefficient of friction(COF)of *** instance,under the normal pressures of 0.05 and 0.2 mPa,the wear rate and COF of the 3-pass UITed sample were lower than those of the L-PBFed sample by 65 and 58%,and 20 and 17%,respectively.

关键词： Laser powder bed fusion Ultrasonic impact treatment Commercially pure Ti(CP-Ti) Surface mechanical properties Tribological properties

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adult neurogenesis:a real hope or a delusion?

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Neural Regeneration Research 2024年第1期19卷 6-15页

作者： Ghulam Hussain Rabia Akram Haseeb Anwar Faiqa Sajid Tehreem iman Hyung Soo Han Chand Raza Jose-Luis Gonzalez De Aguilar Neurochemicalbiology and Genetics Laboratory(NGL) Department of PhysiologyFaculty of Life SciencesGovernment College UniversityFaisalabadPunjabPakistan Department of Physiology School of MedicineClinical Omics InstituteKyungpook National UniversityDaeguKorea Department of Zoology Faculty of Chemistry and Life SciencesGovernment College UniversityLahorePakistan INSERm U1118Mécanismes Centraux et Péripheriques de la NeurodégénérescenceStrasbourgFranceUniversitéde StrasbourgStrasbourgFrance

adult neurogenesis,the process of creating new neurons,involves the coordinated division,migration,and differentiation of neural stem *** process is restricted to neurogenic niches located in two distinct areas of the brain:the subgranular zone of the dentate gyrus of the hippocampus and the subventricular zone of the lateral ventricle,where new neurons are generated and then migrate to the olfactory *** has been thought to occur only during the embryonic and early postnatal stages and to decline with age due to a continuous depletion of neural stem ***,recent years have seen tremendous progress in our understanding of adult brain neurogenesis,bridging the knowledge gap between embryonic and adult ***,we discuss the current status of adult brain neurogenesis in light of what we know about neural stem *** this notion,we talk about the importance of intra cellular signaling molecules in mobilizing endogenous neural stem cell prolife *** on the current understanding,we can declare that these molecules play a role in targeting neurogenesis in the mature ***,to achieve this goal,we need to avoid the undesired proliferation of neural stem cells by controlling the necessary checkpoints,which can lead to tumorigenesis and prove to be a curse instead of a blessing or hope.

关键词： adult neurogenesis aging brain-derived neurotrophic factor dentate gyrus hippocampus neural stem cells neurotrophic factors Notch oxidative stress stem cells subgranular zone

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Identification of pulse-like ground motions using artificial neural network

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Earthquake Engineering and Engineering Vibration 2022年第4期21卷 899-912页

作者： Ahed Habib iman Youssefi mehmet m.Kunt Department of Civil Engineering Eastern Mediterranean University99628 FamagustaNorth Cyprusvia Mersin 10Turkey

For more than 20 years,the concept of near-fault pulse-like ground motion has been a topic of great interest due to its distinct characteristics,particularly due to directivity or fling effects,which are hugely influenced by the rupture *** unexpected characteristics,along with their effective frequency,energy rate,and damage indices,create a near-fault,pulse-like ground motion capable of causing severe damage to *** of the most common approaches for identifying these ground motions is done by conducting wavelet decomposition of the ground motion time history to extract a pulse signal and eventually categorize an earthquake by comparing the original signal to the residual ***,to overcome the intensive calculations required in this approach,this study proposes using artificial neural networks to identify pulse-like ground motions through classification to predict their pulse period by means of regression ***,the study is intended to evaluate the reliability and accuracy of various artificial neural networks in identifying pulse-like ground motions and predicting their pulse *** general,the results of the study have shown that the artificial neural network can identify pulse-like earthquakes and reliably predict their pulse period.

关键词： pulse-like ground motions near-fault artificial neural network identification

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Classifying moisture sources associated with snowfall in the mountains of Lesotho

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Journal of mountain Science 2024年第6期21卷 1941-1953页

作者： Alexi m.mARINAKI Jennifer m.FITCHETT School of Geography Archaeology and Environmental StudiesUniversity of the WitwatersrandPrivate Bag X3Wits 2050South Africa

An average of eight snowfall events occur each year in the eastern Lesotho *** snowfall events are typically associated with cut-off low(CoLs)systems and mid-latitude ***,the moisture sources of the snowfall are unclassified and *** Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model,an air mass back trajectory model,has been used to evaluate moisture source waters locally in southern Africa and internationally in China and *** study uses HYSPLIT to determine the source moisture of snow in Lesotho.A list of all 82 snowfall events in Lesotho spanning 2017 to 2022 was compiled using the Snow Report SA Instagram page,including the date and location of snowfall.A 72-hour back trajectory for each snowfall event was initiated for both Afriski and the whole of *** amounts to models of moisture source trajectories for 28 and 82 snowfall days,*** air mass pathways are classified according to their frequency per snowfall event,per month in the snow season,per year and for the full *** this,associated moisture source regions and dominant air mass trajectories were *** study reports that the air mass trajectories associated with Afriski and Lesotho as a whole are very *** most common pathway of air mass trajectories transporting snow-bearing moisture to Lesotho was an inland trajectory from the northern regions of southern *** pathway makes up 16.6%of all trajectories reported and is associated with the Angola Low,the Congo Air Boundary and the *** High Pressure.

关键词： Eastern Lesotho Highlands Afriski Snow Cut-off Lows HYSPLIT Synoptic Climatology

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The Triple Helix of innovation as a double game involving domestic and foreign actors

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Journal of Data and Information Science 2024年第1期9卷 82-100页

作者： Eustache mêgnigbêto University of Antwerp Antwerpen 2000Belgium

Purpose:The collaboration relationships between innovation actors at a geographic level may be considered as grouping two separate layers,the domestic and the *** the level of each layer,the relationships and the actors involved constitute a Triple Helix *** paper distinguished three levels of analysis:the global grouping together all actors,the domestic grouping together domestic actors,and the foreign related to only actors from partner ***/methodology/approach:Bibliographic records data from the Web of Science for South Korea and West Africa breakdown per innovation actors and distinguishing domestic and international collaboration are analyzed with game *** core,the Shapley value,and the nucleolus are computed at the three levels to measure the synergy between ***:The synergy operates more in South Korea than in West Africa;the government is more present in West Africa than in South Korea;domestic actors create more synergy in South Korea,but foreign more in West Africa;South Korea can consume all the foreign synergy,which is not the case of West *** limitations:Research data are limited to publication records;techniques and methods used may be extended to other research *** implications:West African governments should increase their investment in science,technology,and innovation to benefit more from the synergy their innovation actors contributed at the foreign ***,the results of the current study may not be sufficient to prove that greater investment will yield benefits from foreign ***/value:This paper uses game theory to assess innovation systems by computing the contribution of foreign actors to knowledge production at an area *** proposes an indicator to this end.

关键词： Triple Helix Game theory Core Shapley value Nucleolus South Korea West Africa

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Complexed amino acid minerals ***-glycinate chelated minerals:Impact on the performance of old laying hens

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Animal Nutrition 2024年第1期16卷 395-408页

作者： marcos J.B.Santos maria C.m.m.Ludke Leandro m.Silva Carlos B.V.Rabello mércia R.Barros Fabiano S.Costa Clariana S.Santos Jamille S.S.Wanderley Department of Animal Science Rural Federal University of PernambucoRecifePEBrazil Department of Veterinary Science Rural Federal University of PernambucoRecifePEBrazil

The present study was to evaluate the effect of trace minerals(Zn,mn,and Cu)from complexed amino acid minerals(ZmCAA)and bis-glycinate chelated minerals(ZmCGly)in laying hen diets on performance,internal and external egg quality,yolk mineral deposition,intestinal morphometry,and bone *** 78 to 98 weeks of age,400 White LSL-Lite strain laying hens were distributed in a randomized design with 4 treatments with 10 replicates per *** were distributed in a 2×2 factorial arrangement using either Zn,mn,and Cu of ZmCAA or ZmCGly source at 2 levels:low(20,20,and 3.5 mg/kg of Zn,mn,and Cu,respectively)or high(40,40,and 7 mg/kg of Zn,mn,and Cu,respectively).The analysis of variance was performed,and in cases where differences were observed,the means were compared using Tukey?s test(Pmineral supplementation had a significant impact on the performance of laying *** fed ZmCAA had higher egg production(P=0.01),egg weight(P=0.02),egg mass(P=0.01),and lower feed conversion ratio(P=0.05)compared to those fed *** ZmCAA supplementation showed higher albumen height(P=0.01),albumen weight(P=0.01),and eggshell thickness(Pmn(Pmetry(PmCAA *** the small intestine,ZmCAA resulted in longer villi(P=0.02)and shorter crypt depth(P=0.01)in the *** and ileum measurements were influenced by the level and source of trace minerals(PmCAA exhibited superior performance,egg quality,deposition of trace minerals in the egg yolk,and bone density compared to hens fed *** this study,older laying hens supplemented with ZmCAA at lower levels demonstrated adequate levels of supplementation.

关键词： Bis-glycinates metal-amino acids Radiodensity Trace minerals

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Oxidized organic molecules in the tropical free troposphere over Amazonia

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National Science Review 2024年第1期11卷 174-184页

作者： Qiaozhi Zha Diego Aliaga Radovan Krejci Victoria A.Sinclair Cheng Wu Giancarlo Ciarelli Wiebke Scholz Liine Heikkinen Eva Partoll Yvette Gramlich Wei Huang markus Leiminger Joonas Enroth Otso per?kyl? Runlong Cai Xuemeng Chen Alkuin maximilian Koenig Fernando Velarde Isabel moreno Tuukka Pet?j? Paulo Artaxo Paolo Laj Armin Hansel Samara Carbone markku Kulmala marcos Andrade Douglas Worsnop Claudia mohr Federico Bianchi Institute for Atmospheric and Earth System Research/Physics University of Helsinki Joint International Research Laboratory of Atmospheric and Earth System Sciences Nanjing University Department of Environmental Science & Bolin Centre for Climate Research Stockholm University Department of Chemistry and molecular Biology University of Gothenburg Institute for Ion and Applied Physics University of Innsbruck Ionicon Analytik GmbH Laboratory for Atmospheric Physics Institute for Physics Research Universidad Mayor de San Andrés Institute of Physics University of Sao Paulo Institute for Geosciences and Environmental Research (IGE) University of Grenoble Alpes Agrarian Sciences Institute Federal University of Uberl?ndia Beijing advanced Innovation Center for Soft matter Science and Engineering Beijing University of Chemical Technology Department of Atmospheric and Oceanic Sciences University of Maryland Aerodyne Research Inc. Department of Environmental System Science ETH Zürich Switzerland and Laboratory of Atmospheric Chemistry Paul Scherrer Institute

New particle formation(NPF) in the tropical free troposphere(FT) is a globally important source of cloud condensation nuclei, affecting cloud properties and climate. Oxidized organic molecules(OOms)produced from biogenic volatile organic compounds are believed to contribute to aerosol formation in the tropical FT, but without direct chemical observations. We performed in situ molecular-level OOms measurements at the Bolivian station Chacaltaya at 5240 m above sea level, on the western edge of Amazonia. For the first time, we demonstrate the presence of OOms, mainly with 4–5 carbon atoms, in both gas-phase and particle-phase(in terms of mass contribution) measurements in tropical FT air from Amazonia. These observations, combined with air mass history analyses, indicate that the observed OOms are linked to isoprene emitted from the rainforests hundreds of kilometers away. Based on particle-phase measurements, we find that these compounds can contribute to NPF, at least the growth of newly formed nanoparticles, in the tropical FT on a continental scale. Thus, our study is a fundamental and significant step in understanding the aerosol formation process in the tropical FT.

关键词： oxidized organic molecules tropical aerosol formation Amazon free troposphere

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Quantitative and Qualitative Responses of Hydroponic Tomato Production to Different Levels of Salinity

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Phyton-International Journal of Experimental Botany 2024年第6期93卷 1311-1323页

作者： Khalid A.Al-Gaadi Ahmed m.Zeyada ElKamil Tola Abdullah m.Alhamdan Khalid A.m.Ahmed Rangaswamy madugundu mohamed K.Edrris Department of Agricultural Engineering College of Food and Agriculture SciencesKing Saud UniversityRiyadh11451Saudi Arabia Precision Agriculture Research Chair Deanship of Scientific ResearchKing Saud UniversityRiyadh11451Saudi Arabia Chair of Dates Industry&Technology Deanship of Scientific ResearchKing Saud UniversityRiyadh11451Saudi Arabia Agricultural Research Centre Agricultural Engineering Research Institute(AEnRI)Giza12619Egypt

From economic and nutritional points of view,tomato is,historically,considered one of the most important *** signiﬁcant yield reduction,most commercial cultivars of tomato crops are sensitive to moderate levels of ***,high levels of salt stress can negatively affect the yield and quality of tomato ***,this study was conducted to evaluate the yield and fruit quality of three tomato cultivars(Forester,Ghandowra-F1,and Feisty-Red)cultivated hydroponically,under three different levels of nutrient solution *** of tomato fruits was performed based on quantity(number and weight of fruits,and total fruit yield),physical quality(color andﬁrmness),and chemical quality(refractometric index“Brix”,pH,EC,K^(+),Na^(+),and NO_(3)-).Experiments were conducted using three salinity levels of the nutrient solution with electrical conductivity values(dSm^(-1))of 2.5(control),6.0,and *** showed that the studied tomato cultivars were signiﬁcantly inﬂuenced by high salinity(9.5 dSm^(-1))in comparison to the low(2.5 dSm^(-1))and medium(6.0 dSm^(-1))levels of *** average,the highest fruit weight per plant of 1944.84 g and total fruit yield of 4.42 kgm^(-2) were observed at the low salinity level;however,no signiﬁcant differences were obtained in the two yield factors(single fruit weight and total fruit yield)for the low and medium salinity *** the other hand,a signiﬁcant reduction in tomato yield(31%)was associated with the high salinity level compared to the yield at low and medium salinity *** of physical quality parameters showed highly signiﬁcant differences among all salinity *** average,the maximum value of color change(1.72)was associated with the medium salinity level,and the maximum value ofﬁrmness(9.61 Ncm^(-1))was recorded at the high salinity *** levels and tomato cultivars introduced signiﬁcant differences in chemical quality parameters;however,no signiﬁcant differences in these

关键词： Quality cultivars yield color ﬁrmness brix

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Comparative analysis of planted and unplanted controls for assessment of rhizosphere priming effect

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Pedosphere 2022年第6期32卷 884-892页

作者： Jian LI per BENGTSON Department of Biology Microbial Ecology GroupLund UniversitySölvegatan 37Lund 22362(Sweden) Key Laboratory of Urban Environment and Health Institute of Urban EnvironmentChinese Academy of Sciences1799 Jimei RoadXiamen 361021(China)

The rhizosphere priming effect(RPE)is increasingly being considered to be an important regulator of soil organic matter(SOm)decomposition and nutrient turnover,with potential importance for the global CO_(2) *** a result,studies on the RPE have rapidly increased in number over the last few *** of these experiments have been performed using unplanted soil as the control,which could potentially lead to incorrect assessment of the ***,we performed a greenhouse experiment to investigate how the choice of control(i.e.,unplanted control and planted control)influenced the quantification of RPE on SOm decomposition and gross nitrogen(N)mineralization,and to link this to differences in microbial and abiotic soil properties between the two *** the planted control,planted seedlings were cut at soil surface 5 d before measurement of the *** RPE on SOm decomposition was positive in pine soil and almost 2-fold higher when calculated from the planted control than from the unplanted *** spruce soil,a negative RPE on SOm decomposition was found when calculated from the planted control,while the RPE was positive when calculated from the unplanted *** RPE on gross N mineralization was found when calculated from the planted control,while a positive RPE of more than 100%was found when calculated from the unplanted *** microbial biomass and growth rate were lower,while the inorganic N content was higher in the unplanted control than in the planted *** microbial community composition and potential enzyme activity in the planted treatment and planted control were similar,but they differed significantly from those in the unplanted *** results showed that the RPE varied widely depending on the choice of control;thus,we suggest that a planted control,in which the aboveground plant parts are removed only a few days before the measurement of RPE,should be used as the control when elucidating the RPE on belowground C and N

关键词： enzyme activity gross nitrogen mineralization microbial community composition nitrogen availability soil organic matter decomposition

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Post-fire recovery of Puya raimondii, vegetation and birds in the puna of Huascarán National Park, perú

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Journal of mountain Science 2024年第1期21卷 20-32页

作者： mery L.SUNI Giovana P.VadILLO César ARANA Enoc JARA-PENA Letty SALINAS m.Estela PONCE Paul m.RAmSAY Plant Physiology Laboratory Faculty of Biological SciencesUniversidad Nacional Mayor de San MarcosLima 15081Peru Natural History museum Universidad Nacional Mayor de San MarcosLima 15072Peru Applied Phytology Laboratory Faculty of Biological SciencesUniversidad Nacional Mayor de San MarcosLima 15081Peru Department of Statistics Faculty of Mathematical SciencesUniversidad Nacional Mayor de San MarcosLima 15081Peru Department of Chemical and Biological Sciences Universidad de las Américas PueblaSan Andrés Cholula CP Cholula CP 72810Mexico

A large fire of 233 ha in Huascarán National Park in peru provided an opportunity to compare plant and bird responses in burned and nearby unburned zones of the puna. Heights and live diameters of flagship Puya raimondii rosettes(assigned to four broad developmental phases), plant communities(66 species in 24 families and nine growth forms) and bird communities(77 species in six trophic guilds) were monitored after the fire. Although no mortality was observed, Puya raimondii plants were affected by the fire, losing approximately 60% of their photosynthetic area across all developmental phases, but recovered quickly during the first two years after fire. The comparison of Puya rosette recovery after fire was complicated by the changes in live rosette diameter for unburned plants, which showed plasticity of photosynthetic area linked to seasonal and annual fluctuations in precipitation in this relatively dry environment(decreased by 26% for mature adult plants over the study period). Fire caused an immediate change in the density, biomass and composition of vegetation. Although the species present remained similar, their abundances changed significantly immediately after the fire, with notable reductions in dominant tussock grasses. This provided opportunities for other plants, resulting in higher postfire diversity of plant species, genera, families and growth forms. In turn, the changes in vegetation after fire affected the composition of birds according to their trophic guild. Granivores largely disappeared,generalists were mostly unaffected, and other guilds showed a more complex response. As the vegetation recovered, most displaced birds returned within approximately one year.

关键词： Burning Plant biomass Trophic guilds Andes Giant rosette plants

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