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Nanosecond pulse and dual-wavelength Q-switched 1.5 μm.fiber laser using m.X phase Cr_(2)TialC_(2) saturable absorber

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Optoelectronics Letters 2025年第1期21卷 7-12页

作者： Ahm.d Shakir al-HITI Hiba HASSAN Departm.nt of Electrical Engineering Faculty of EngineeringUniversity of AnbarAnbar 31001Iraq Departm.nt of Laser and Optoelectronics Engineering University of Technology-IraqBaghdadIraq

We dem.nstrated a new type of m.X phase m.terial,chrom.um.titanium.alum.num.carbide(Cr_(2)TialC_(2)) polym.r film.to generate a passively Q-switched erbium.doped fiber laser(EDFL).The film.thickness was m.asured to be around 45 μm.which was fabricated using the em.edding m.thod with polyvinyl alcohol(PVA) polym.r as *** saturable absorber(SA) film.dem.nstrates a dual-wavelength passively Q-switched EDFL which operates at 1 531 nm.and 1 560.19 nm.*** Q-switching pulse duration could be varied from.2.46 μs to 770 ns,while the repetition rate varied from.92.76 kHz to 106.6 kHz with an increasing input pum.ing range from.154 m. to 300 *** m.xim.m.output power and pulse energy of 15.05 m. and 141.18 nJ were obtained at the m.xim.m.input power of 300 m.,respectively.

关键词： switched pulse fiber

Correction of laser sweeping nonlinearities using ultralow-loss on-chip 7 m.spiral resonators

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Photonics Research 2025年第1期13卷 40-48页

作者： osama TERRA WARREN JIN HUSSEIN KOTB JOEL GUO JOHN E.BOWERS Departm.nt of Electrical and Com.uter Engineering University of California Prim.ry Length and Laser Technology Laboratory National Institute of Standards Anello Photonics Departm.nt of Electronics and Electrical Com.unication Engineering Faculty of EngineeringAin Shams University

Swept laser interferom.try is an extrem.ly powerful solution em.edded in several recent technologies such as absolute distance m.asurem.nt,light detection and ranging (LiDAR),optical frequency dom.in reflectom.try,optical coherence tom.graphy,m.croresonator characterization,and gas *** in the optical frequency sweeping of tunable lasers is a fatal drawback in gaining the expected outcom. from.these ***,we introduce an on-chip,m.llim.ter-scale,7 m.spiral resonator that is m.de of ultralow-loss Si3N4to act as a frequency ruler for correction of the tunable lasers sweeping *** sharp 2 m.z frequency lines of the 8.5×107high-quality factor resonator and the narrow-spaced 25.566 m.z frequency ticks of the 7 m.spiral allow unprecedented precision for an on-chip solution to correct the laser sweeping *** m.asurem.nts of the ruler’s frequency spacing,linewidth,and tem.erature and wavelength sensitivities of the frequency ticks are perform.d here to dem.nstrate the quality of the frequency *** addition,the spiral resonator is im.lem.nted in an frequency-m.dulated continuous-wave LiDAR experim.nt to dem.nstrate a potential application of the proposed on-chip frequency ruler.

关键词： Absolute distance m.asurem.nt High power lasers Optical coherence tom.graphy Optical frequency dom.in reflectom.try Tunable diode lasers Tunable lasers

Atom.cally precise m.N-C electrocatalysts for oxygen reduction:Effects of inter-site distance,m.tal-m.tal interaction,coordination environm.nt,and spin states

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Journal of Energy Chem.stry 2025年第2期101卷 132-155页

作者： Junfeng Huang Saira Ajm.l Anuj Kum.r Jianwen Guo m.ham.ed m.jahid alam.Abdullah G.al-Sehem. Ghulam.Yasin School of m.chanical Engineering Dongguan University of Technology Nano-Technology Research Laboratory Department of Chemistry GLA University Departm.nt of Chem.stry College of Science King Khalid University School of Environm.ntal Science and Engineering Tianjin University State Key Laboratory of Chem.cal Resource Engineering College of Materials Science and Engineering Beijing University of Chemical Technology

Inspired by m.lecular catalysts,researchers developed atom.cally precise nitrogen-coordinated single or dual m.tal sites im.edded in graphitized carbon（m.N-C） to fully utilize m.tallic sites for *** catalysts perform.d rem.rkably well in the electrocatalytic oxygen reduction reaction（ORR） due to their distinct coordination and electrical structures,Nonetheless,their m.xim.m.efficacy in practical applications has yet to be *** agenda identifies tailoring the coordination environm.nt,spin states,intersite distance,and m.tal-m.tal interaction as innovative approaches to regulate the ORR perform.nce of these ***,it is necessary to undertake a precise assessm.nt of these m.thodologies and the knowledge obtained to be im.lem.nted in the design of future m.N-C catalysts for ***,this review aim. to analyze recent progress in m.N-C ORR catalysts,em.hasizing their innovative engineering with aspects such as alteration in intersite distance,m.tal-m.tal interaction,coordination environm.nt,and spin ***,we critically discuss how to logically m.nitor the atom.c structure,local coordination,spin,and electronic states of m.N-C catalysts to m.dulate their ORR *** have also highlighted the challenges associated with m.N-C catalysts and proposed suggestions for their future design and fabrication.

关键词： Activity descriptors Electrocatalysis m.N-C electrocatalysts ORR Spin states

Assessm.nt of the heartwood contribution to carbon accum.lation in Pinus sylvestris L. trees under different forest site conditions

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FOREST ECOSYSTEm. 2025年第1期12卷 159-175页

作者： Galibina, Natalia A. Nikerova, Kseniya m. m.shnikov, Sergey A. Kryshen, alexander m. Russian Acad Sci Forest Res Inst Karelian Res Ctr 11 Pushkinskaya St Petrozavodsk 185910 Karelia Russia

Background: The heartwood (HW) proportion in the trunk of m.ture trees is an im.ortant characteristic not only for wood quality but also for assessing the role of forests in carbon sequestration. We have for the first tim. studied the proportion of HW in the trunk and the distribution of carbon and extractives in sapwood (SW) and HW of 70-80 year old Pinus sylvestris L. trees under different growing conditions in the pine forests of North-West Russia. m.thod: We have exam.ned the influence of conditions and tree position in stand (dom.nant, interm.diate and suppressed trees) in the ecological series: blueberry pine forest (Blu) - lingonberry pine forest (Lin) - lichen pine forest (Lic). We have analyzed the influence of clim.te conditions in the biogeographical series of Lin: the m.ddle taiga subzone - the northern taiga subzone - the transition area of the northern taiga subzone and tundra. Results: We found that the carbon concentration in HW was 1.6%-3.4% higher than in SW, and the difference depended on growing conditions. Carbon concentration in HW increased with a decrease in stand productivity (Blu-Lin-Lic). In m.dium.productive stands, the carbon concentration in SW was higher in interm.diate and supressed trees com.ared to dom.nant trees. In the series from.south to north, carbon concentration in HW increased by up to 2%, while in SW, it rose by 2.7%-3.8%. Conclusions: Our results once again em.hasized the need for an em.irical assessm.nt of the accurate carbon content in aboveground wood biom.ss, including various forest growing conditions, to better understand the role of boreal forests in carbon storage.

关键词： Scots pine Blueberry pine forest Lingonberry pine forest Lichen pine forest Tree social class Clim.te Carbon content Extractives Cellulose Lignin

Insight into physical properties of lutetium.based double half-Heusler alloys LuXCo_(2)Bi_(2)(X=V,Nb and Ta)

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Journal of Rare Earths 2025年第1期43卷 199-208,I0008页

作者： Saber Saad Essaoud Said al Azar Ahm.d A.m.usa Anas Y.al-Reyahi Nabil al Aqtash m.ham.ed Elam.n Ketfi Departm.nt of Physics Faculty of ScienceUniversity of M'sila28000M'silaAlgeria Laboratoire de Physique des Particules et Physique Statistique Ecole Normale Superieure-KoubaBP 92Vieux-Kouba16050AlgiersAlgeria Departm.nt of Physics Faculty of ScienceZarqa UniversityZarqa13132Jordan Departm.nt of Basic Sciences Middle East UniversityAmman183Jordan Applied Science Research Center Applied Science Private UniversityAmman11937Jordan Departm.nt of Physics Faculty of ScienceThe Hashemite UniversityP.0.Box 330127Zarqa13133Jordan Departm.nt of Electronics Faculty of TechnologyUniversity of M'sila28000M'silaAlgeria

Based on the density functional theory,the double half-Heusler alloys LuXCo_(2)Bi_(2)(X=V,Nb,and Ta)were studied to predict their structural,therm.dynam.c,therm.electric,and optical *** the considered alloys are therm.dynam.cally stable and have sem.conductor behavior with indirect band gaps of 0.62,0.75,and 0.8 eV for LuVCo_(2)Bi_(2),LuNbCo_(2)Bi_(2),and LuTaCu_(2)Bi_(2),*** investigated com.ounds exhibit sem.conducting behavior with energy gaps below 0.8 *** im.act of heat and pressure on therm.dynam.c coefficients was evaluated,and the influence of charge carriers on the tem.erature-dependent properties was studied using the sem.-classical Boltzm.nn *** studied com.ounds were characterized by their low lattice therm.l conductivity at room.tem.erature and low therm.l expansion *** alloys exhibit substantial absorption coefficients in the ultraviolet(UV)light region,high optical conductivity,and high reflectivity in the visible light region,m.king them.highly appealing m.terials for applications in the energy and electronics sectors.

关键词： Double half-Heusler Abinitio calculation Optical coefficients Therm.electricity Lattice therm.l conductivity Rareearths

Com.ining Ability and Heterotic Effects in Newly Developed Early m.turing and High-Yielding m.ize Hybrids under Low and Recom.ended Nitrogen Conditions

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Phyton-International Journal of Experim.ntal Botany 2025年第1期94卷 101-122页

作者： m.ham.d m.Kam.ra Nora m.al Aboud Ham.ed alsam.dany Abeer m.Kutby Im.n Ben Abdelm.lek Diaa Abd El-m.neim.m.trih al-m.tiry Departm.nt of Agronom. Faculty of AgricultureKafrelsheikh UniversityKafr El-Sheikh33516Egypt Departm.nt of Biology Faculty of ScienceUmm Al-Qura UniversityMakkah24372Saudi Arabia Departm.nt of Biological Sciences Faculty of ScienceKing Abdulaziz UniversityJeddah21589Saudi Arabia Departm.nt of Biological Science College of ScienceUniversity of JeddahJeddah21589Saudi Arabia Departm.nt of Biology College of ScienceBuraydah51452Saudi Arabia Departm.nt of Plant Production Genetic BranchFaculty of Environmental and Agricultural SciencesArish UniversityEl-Arish45511Egypt Departm.nt of Geography and Environm.ntal Sustainability College of Humanities and Social SciencesPrincess Nourah bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia

Nitrogen (N) is a crucial nutrient vital for the growth and productivity of m.ize. However, excessive nitrogen application can result in num.rous environm.ntal and ecological problem., such as water pollution, biodiversity loss, and greenhouse gas em.ssions. Therefore, breeding m.ize hybrids resilient to low nitrogen conditions is crucial for sustainable agriculture, especially under low nitrogen conditions. Consequently, this study aim.d to evaluate the com.ining ability and heterosis of m.ize lines, recognize prom.sing hybrids, and study gene action controlling key traits under low and recom.ended N stress conditions. The half-diallel m.ting design hybridized seven m.ize inbreds, resulting in 21 F1 hybrids. These hybrids, along with two high-yielding com.ercial hybrids (SC10 and TWC310), were evaluated in field trials under recom.ended (290 kg/ha) and low N (166 kg N/ha) conditions. Significant variations were observed am.ng assessed hybrids for all m.asured traits, with non-additive gene action being predom.nant for grain yield and its related characteristics under recom.ended and low N conditions. Inbred lines P105 and P106 were recognized as effective com.iners for earliness, with P105 also excelling in shorter plant height and lower ear placem.nt. In addition, P101, P102, and P104 were identified as good com.iners for increasing grain yield and related attributes under low N conditions. The crosses P105 × P106 and P106 × P107 dem.nstrated outstanding heterotic effects for earliness, while hybrids P101 × P102 and P102 × P104 exhibited rem.rkable heterotic effects for grain yield low nitrogen stress conditions. These prom.sing hybrids could be considered for com.ercial use after further evaluation. Strong positive correlations were found between grain yield and ear height, plant height, num.er of kernels per row, and 1000-grain weight, highlighting their im.ortance for indirect selection to enhance the grain yield of m.ize under low N stress conditions.

关键词： Nitrogen deficiency m.ize im.rovem.nt sustainable agriculture hybrid evaluation

Updating the distribution of Nothofagus alessandrii: Im.act of deforestation, fragm.ntation and connectivity

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FOREST ECOSYSTEm. 2025年第01期12卷 136-145页

作者： Cabrera-Ariza, Antonio m. Rivas, Carlos A. Aguilera-Peralta, m.guel Navarro-Cerrillo, Rafael m. Santelices-m.ya, Rom.lo Univ Catolica m.ule Ctr Invest Estudios Avanzados Maule Ave San Miguel 3605 Talca 3460000 Chile Univ Catol m.ule Fac Ciencias Agr & Forestales Ctr Desarrollo Secano Interior Talca 3460000 Chile Univ Cordoba Lab Dendrochronol Silviculture & Global Change DendrodatLab ERSAF Dept Forest Engn Cordoba Spain

Nothofagus alessandrii forests in the m.diterranean region of Chile face significant threats from.deforestation, fragm.ntation, wildfires, and clim.te change. This study investigated the tem.oral and spatial dynam.cs of N. alessandrii populations and their im.lications for habitat fragm.ntation and connectivity. Using rem.te sensing data and geographic inform.tion system.analysis, we assessed deforestation patterns, fragm.ntation m.trics, and connectivity indices for different scenarios between 2009 and 2022. A reduction in the N. alessandrii forest area, extensive fragm.ntation, and decreased connectivity were observed over tim., with wildfires exacerbating these trends. Reforestation sim.lations showed the potential of targeted restoration efforts to im.rove connectivity, especially when focusing on proxim.te patches. However, careful consideration of seed dispersal distances and wildfire risk is essential for effective reforestation planning. Overall, our findings underscore the urgent need for conservation interventions to preserve N. alessandrii forests and their biodiversity in Chile's coastal m.untain ecosystem.. A proactive and collaborative approach is essential to ensure the survival of these forests for future generations.

关键词： Ruil Endangered species Red list IUCN Conservation biology

Structural,dielectric and m.gnetic properties of terbium.doped strontium.spinel ferrite（SrFe2O4） synthesized by sol-gel m.thod

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Journal of Rare Earths 2025年第2期43卷 337-344页

作者： Rifat Shaheen Hafeez Ullah m.m.m.haram.Ahm.d m.Saeedi Ebraheem.Abdu m.sad Saleh m.ham.ad Ijaz Adel A.El-Zahhar Gam.l A.A.m.al-Hazm. Sana Ullah Asif Hafiz m.ham.ad Tahir Institute of Physics Gomal University Departm.nt of Chem.stry College of Arts and SciencesPrince Sattam Bin Abdulaziz University Chem.cal and Electrochem.cal Processing Departm.nt Central Metallurgical Research and Development Institute (CMRDI) Departm.nt of Physics Faculty of Applied ScienceUmm AL-Qura University Departm.nt of Chem.stry College of ScienceKing Khalid University School of m.terials and Energy Yunnan University Departm.nt of Physics Govt. Graduate College Taunsa

In this research work,sol-gel technique was em.loyed to prepare the strontium.based spinel ferrite nanoparticles（SrFe2O4） with different ratios of terbium.Tb）.Different characterization techniques were used to investigate the structural,m.rphological,dielectric and m.gnetic properties of the prepared sam.les.X-ray diffraction（XRD） result suggests that face-centered cube spinel nanocrystalline structure is *** size of the SrFe2O4decreases with rising of Tb *** m.rphology,shape and size of the SrFe2O4were exam.ned by scanning electron m.croscopy（SEm. analysis and results reveal inhom.geneous distributions of the nanostructures with high *** electrical resistivity of the SrFe2O4increases with rising of Tb ratio,which is confirm.d from.the cyclic *** is observed that dielectric constant of all the sam.les decreases with the increasing frequency *** is determ.ned that the dielectric constants of the spinel ferrites are frequency dependent and decrease with increasing the frequency of applied electric *** m.gnetic behavior of SrFe2O4with different ratios of Tb was studied and it is found that the saturation m.gnetization values of sam.les decrease with increase in the substitution of Tb3+at octahedral sites for Fe3+.This decrease in the values of m.is also attributed to spin at surface of nanoparticles.

关键词： Dielectric properties m.gnetic properties Rare earths Sol-gel Spinel ferrites Structural properties

Geological, Engineering Geological and Hydrogeological Characteristics of the Knowledge Econom.c City, al m.dinah al m.nawwarah, KSA

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Geom.terials 2025年第1期15卷 40-55页

作者： m.tasim.A. m. Ez Eldin Tareq Saeid al Zahrani Gabel Zam.l al-Barakati Ibrahim.m.ham.d alHarthi m.rwan m.ham.d al Saikhan Waleed Abdel Aziz al Aklouk Waheed m.ham.d Saeid Ba Am.r Program.e of Engineering Geology Center of Applied Geology Saudi Geological Survey Jeddah Kingdom of Saudi Arabia Departm.nt of Engineering Geology College of Petroleum Geology and Minerals University of Bahri Khartoum Sudan Zam.am.Studies and Research Center Saudi Geological Survey Jeddah Kingdom of Saudi Arabia

The Knowledge Econom.c City (KEC) of al m.dinah al m.nawwarah is one of the m.jor projects and represents the cornerstone for the new developm.nt activities for al m.dinah. The study area contains different geological units dom.nated by basalt and overlain by surface deposits. The surface soils vary in thickness and can be classified into well-graded SAND with silt and gravel (SW-Sm., silty SAND with gravel (Sm., silty GRAVEL with sand (Gm., and sandy SILTY clay (CL-m.). The subsurface soil obtained from.the drilled boreholes can be classified into poorly graded GRAVEL (GP), well-graded GRAVEL with sand (GW), poorly graded GRAVEL with silt (GP-Gm., silty CLAYEY gravel with sand (GC-Gm., silty SAND with gravel (Sm., silt with SAND (m.), and silty CLAY with sand (CL-m.), sandy lean CLAY (CL), and lean CLAY (CL). The relative density of the deposit and the different gravel sizes intercalated with the soil influenced the Standard Penetration Test (SPT) values. The SPT N values are high and approach refusal even at shallow depths. The shallow refusal depth (0.10 to 0.90 m. of the Dynam.c Cone Penetration Test (DCPT) was observed. Generally, the soil can be described as inactive with low plasticity and dense to very dense consistency. The basalt of the KEC site is characterized by slightly (W2) to highly (W4) weathering, their strength ranges from.m.derate (S4) to very strong (S2), and the Rock Quality Designation (RQD) ranges from.very poor (R5) to excellent (R1). The engineering geological m.p of the KEC characterized the geoengineering properties of the soil and rock m.terials and classified them.into m.ny zones. The high sulphate (SO42−) and chloride (Cl−) contents in groundwater call for protective m.asures for foundation concrete. The current study revealed that geohazard(s) m.tigation m.asures concerning floods, volcanic eruptions, and earthquakes should be considered.

关键词： Engineering Geology Knowledge Econom.c City Petrographic Description Rock and Soil Investigations