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Influence of erbium on structural,and ch.r.ed particles,photons,and neutrons shielding properties of Ba_(1-x)Er_(x)SnO_(3) perovskite ceramics

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Journal of rare Earths 2024年第4期42卷 724-732页

作者： M.K.h.hamad Nidal Dwaikat M.h.A.Mh.r.b M.I.Sayyed r.M.hamad Y.S.M.Alajerami M.A.Almessiere Gameel Saleh Ahmad hussein Alomari K.A.Ziq Department of Basic Sciences School of Social and Basics SciencesAl Hussein Technical UniversityKing Abdullah II St 242Amman11831Jordan Department of Physics College of Engineering and PhysicsInterdisciplinary Research Center for Advanced MaterialsKing Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Department of Physics College of ScienceImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia Basic and Applied Scientific research Center Imam Abdulrahman Bin Faisal UniversityP0.Box 1982Dammam31441Saudi Arabia Department of Physics Faculty of ScienceIsra UniversityAmman11622Jordan Department of Nuclear Medicine research Institute for Research and Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityPo.Box 1982Dammam31441Saudi Arabia Medical Imaging Department Applied Medical Sciences FacultyAl Azhar University-Gaza CityPo.Box 1277Palestine Department of Biophysics Institute for Research and Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityPo.Box1982Dammam 31441Saudi Arabia Department of Biomedical Engineering College of EngineeringImam Abdulrahman Bin Faisal UniversityPo.Box 1982Dammam31441Saudi Energy&Minerals regulatory Commission Amman11821Jordan

Five perovskite ceramics samples of Ba_(1-x)Er_(x)SnO_(3) with x=0.00,0.05,0.10,0.15,and 0.20 were synthesized using the conventional solid-state reaction *** prepared samples were ch.r.cterized by X-ray diffraction(XrD),Fourier transforms infrared(FTIr),and UV-Vis *** shielding properties against ionizing radiation were also *** XrD analysis shows the perovskite cubic structure as the major phase in all *** FTIr reveals a distinctive band around 614-620 cm^(-1) ascribed to the antisymmetric O-Sn-O ***-Vis spectroscopy was used to determine the bandgap according to diffuse reflectance,and the results display a fixed enhancement in the bandgap from 3.2 to 3.3 eV for all ***-ray shielding properties of the synthesized samples were experimentally measured and compared with XCOM computational *** relative differences(Δ,%)between experimental and theo retical values are low and fall within the 0.446%-7.10%*** addition of Er leads to the enhanced density,neutron,and gamma shielding *** contrast,ch.r.ed particles’shielding parameters gradually reduce with.r.sing Er *** results suggest that Ba_(1-x)Er_(x)SnO_(3) samples can be used in different radiation shielding applications.

关键词： Perovskite Ceramics Gamma ray shielding Mass stopping power rare earths

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生物化学简明教程

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作者： (美)马休兹.h.r.等

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印度h.r.talyangar地区晚中新世猪类化石新材料

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古脊椎动物学报（中英文） 2024年第1期62卷 69-84页

作者： Anek r.SANKhYAN Olivier ChAVASSEAU 古生物研究会古马尔温174021印度喜马偕尔邦法国普瓦蒂埃大学法国国家科学研究中心UMR 7262普瓦蒂埃市86073

描述了印度北部比拉斯布尔区喜马偕尔邦h.r.talyangar地区中西瓦利克的猪类化石上、下颌及牙齿材料。h.r.talyangar地区以晚中新世动物群、古人类和其他灵长类动物的多样性而闻名。研究材料为作者之一(ArS)在该地区多次野外季采集的猪... 详细信息

描述了印度北部比拉斯布尔区喜马偕尔邦h.r.talyangar地区中西瓦利克的猪类化石上、下颌及牙齿材料。h.r.talyangar地区以晚中新世动物群、古人类和其他灵长类动物的多样性而闻名。研究材料为作者之一(ArS)在该地区多次野外季采集的猪类化石;猪类化石地点和最近报道的长鼻类化石地点(含古猿化石地点)均被绘制在地图上。这些化石地点广泛分布于Makkan Khad到Sir Khad区域内的“Lower Alternations”层和“Upper Alternations”层。猪类化石被鉴定为3个属:原河猪属Propotamochoerus(***)、河马齿河猪属hippopotamodon(***)和云南猪属Yunnanochoerus(***)。Propotamochoerus hysudricus为中西瓦利克最常见的化石猪类,新发现的Yunnanochoerus dangari进一步证明这种古猪类化石仅在h.r.talyangar地区有少量遗存。h.r.talyangar地区新发现的猪类化石组成与巴基斯坦的Nagri动物群相近。基于猪类化石进行的Potwar高原年代地层学对比表明,h.r.talyangar地区的“Lower Alternations”层的年龄范围为~10–9 Ma,与最新的磁极性地层学年代范围很接近。

关键词：中西瓦利克晚中新世猪超科云南猪属原河猪属河马齿河猪属

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Atomistic Investigation of Shock-Induced Amorphization within Micro-shear Bands in hexagonal Close-Packed Titanium

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Acta Metallurgica Sinica(English Letters) 2024年第9期37卷 1590-1600页

作者： Z.C.Meng K.G.Wang T.Ali D.Li C.G.Bai D.S.Xu S.J.Li A.h.Feng G.J.Cao J.h.Yao Q.B.Fan h.Wang r.Yang Institute of Metal research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Interdisciplinary Centre for Additive Manufacturing(ICAM) School of Materials and ChemistryUniversity of Shanghai for Science and TechnologyShanghai 200093China School of Materials Science and Engineering Tongji UniversityShanghai 201804China Key Laboratory for Light-Weight Materials Nanjing Tech UniversityNanjing 210009China National Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China

The mechanical response of a single crystal titanium sample against(0001)α surface impact was investigated using molecular dynamics ***,non-uniform plastic deformation was observed in the *** high strain rates,amorphization occurred near the edge of the contact region wh.r. severe shear strain induced a large number of stacking faults(SFs)and *** contrast,the central part of the contact region underwent less deformation with significantly fewer ***,instead of amorphization by consuming SFs and dislocations,th.r. was a gradual increase in the density of dislocations and SFs during the process of *** local amorphous regions eventually grew into shear bands.

关键词： Shock compression Amorphization Shear band Titanium Molecular dynamics

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王奎仁石：一种铅的氯化物-亚硒酸盐新矿物

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矿物学报 2024年

作者：杨和雄谷湘平谢先德彭捷 r.B.Gibbs r.T.Downs 亚利桑那大学地球科学系江西应用科技学院光华宝石与矿物资源学院中南大学地球科学与信息物理学院中国科学院地球化学研究所矿物学与成矿学重点实验室/广东省矿物物理与材料重点实验室美国蒙特利市CuestaVista大道24号

王奎仁石（wangkuirenite），理想式Pb3Cl2(Se4+O3)2，发现于意大利撒丁岛巴库鲁奇（Baccy rucci）铅-砷老矿山。该新矿物以板状或叶片状晶体产出，与其共生的矿物有兰硒铜矿、沃兰迪石、硒铅矾、铅矾和石英。王奎仁石在透射光下为很淡... 详细信息

王奎仁石（wangkuirenite），理想式Pb3Cl2(Se4+O3)2，发现于意大利撒丁岛巴库鲁奇（Baccy rucci）铅-砷老矿山。该新矿物以板状或叶片状晶体产出，与其共生的矿物有兰硒铜矿、沃兰迪石、硒铅矾、铅矾和石英。王奎仁石在透射光下为很淡的黄色，晶体透明、具玻璃光泽，条痕为白色，性脆，其摩氏硬度约为3。沿（001）面的解理完全，未观察到有双晶或裂理。计算密度为6.48 g/cm3。根据电子探针分析结果和基于每个单元中有8个（O+Cl）原子获得王奎仁石的经验化学式为Pb3.01Cl1.96(Se1.00O3.02)2。王奎仁石是与人工合成Pb3Cl2（Se O3）2相对应的天然矿物，与人工合成的Pb3Br2（SeO3）2和Pb3I2（SeO3）2具有相同的晶体结构。王奎仁石属单斜晶系，空间群为C2/c，晶胞参数为a=13.4266（4）,b=5.5826（2）,c=13.0024（4）?，β=94.287（2）o，V=971.87（5）?3,Z=4。王奎仁石晶体结构的特点具有平行于（001）面的Pb2+-(Se4+O3)2–结构层，层间靠阴离子Cl-相互连结起来。结构中一个非对称的单元内，存在有两种不同位置的的Pb2+阳离子（Pb1和Pb2）、一个(Se4+O3)2-阴离子团和一个Cl-阴离子。该Se4+阳离子与3个O原子相结合，形成(Se4+O3)2-三次配位。两个Pb1和Pb2均为8次配位，分别为[PbCl2O6]和[PbCl3O5]，阴离子O和Cl围绕Pb1和Pb2的分布表明，它们的6s2孤对电子是惰性的。王奎仁石是迄今记录到的6个铅的氯化物-亚硒酸盐矿物中的一个成员，在结构和成分上它与萨拉巴斯石[sarrabusite,Pb5CuC l4（SeO3）4]紧密相关。

关键词：王奎仁石铅-氯化物-亚硒酸盐新矿物巴库鲁奇意大利

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Carbon dioxide enrichment affected flower numbers transiently and increased successful post-pollination development stably but without altering final acorn production in mature pedunculate oak (Quercus robur L.)

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Journal of Forestry research 2024年第4期35卷 1-12页

作者： ryan McClory rich.r. h.Ellis Martin Lukac Jo Clark Carolina Mayoral Kris M.h.r. Andrew r.G.Plackett A.rob MacKenzie School of Agriculture Policy and DevelopmentUniversity of ReadingAgricultureEarley GateWhiteknights RoadPO Box 237Reading RG66EUUK Faculty of Forestry and Wood Sciences Czech University of Life Sciences PraguePrague 165000Czechia Future Trees Trust Harwell Innovation CentreBuilding 173Curie AvenueHarwellOxford OX110QGUK Birmingham Institute of Forest research University of BirminghamEdgbastonBirmingham B152TTUK School of Biosciences University of BirminghamEdgbastonBirmingham B152TTUK School of Geography Earth and Environmental SciencesUniversity of BirminghamEdgbastonBirmingham B152TTUK

Acorn production in oak(Quercus spp.)shows considerable inter-annual variation,known as masting,which provides a natural defence against seed predators but a highly-variable supply of acorns for uses such as in commercial tree planting each *** emissions of greenhouse gases have been very widely reported to influence plant growth and seed or fruit size and quantity via the‘fertilisation effect’that leads to enhanced *** examine if acorn production in mature woodland communities will be affected by furth.r.increase in CO_(2),the contents of litter traps from a Free Air Carbon Enrichment(FACE)experiment in deciduous woodland in central England were analysed for numbers of flowers and acorns of pedunculate oak(Quercus robur L.)at different stages of development and their predation levels under ambient and elevated CO_(2) ***-annual variation in acorn numbers was considerable and cyclical between 2015 and 2021,with the greatest numbers of mature acorns in 2015,2017 and 2020 but almost none in *** numbers of flowers,enlarged cups,immature acorns,empty acorn cups,and galls in the litter traps also varied amongst years;comparatively high numbers of enlarged cups were recorded in 2018,suggesting *** at this site is a fruit maturation masting species(i.e.,the extent of abortion of pollinated flowers during acorn development affects mature acorn numbers greatly).raising the atmosph.r.c CO_(2) concentration by 150μL L^(−1),from early 2017,increased the numbers of immature acorns,and all acorn evidence(empty cups+immature acorns+mature acorns)detected in the litter traps compared to ambient controls by 2021,but did not consistently affect the numbers of flowers,enlarged cups,empty cups,or mature *** number of flowers in the elevated CO_(2) plots’litter traps was greater in 2018 than 2017,one year after CO_(2) enrichment began,wh.r.as numbers declined in ambient *** with CO_(2) also increased the number o

关键词： Quercus robur L. Acorns Masting Pedunculate oak Carbon dioxide

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reflections on four decades of physical activity epidemiology

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Journal of Sport and health Science 2024年第5期13卷 608-610页

作者： Barbara Sternfeld David r.Jacobs Jr. Division of research Kaiser Permanente Northern CaliforniaOaklandCA 94610USA Division of Epidemiology and Community health School of Public HealthUniversity of MinnesotaMinneapolisMN 55454USA

In 1985,Public health.r.ports published a series of papers prepared for a workshop sponsored by the Centers for Disease Control and Prevention(CDC).1 Building on the seminal work of Jeremy Morris and ralph Paffenbarger Jr.,who were among the first to use epidemiological methods to study physical activity(PA),2,3 the workshop itself was the result of a growing scientific understanding of the importance of“physical fitness and exercise for improving the health of the public”.

关键词： semi workshop ralph

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Novel synthesis of stabilized Bi_(1-x-y)Gd_(x)Dy_(y)O_(1.5) solid electrolytes with enhanced conductivity for intermediate temperature solid oxide fuel cells(SOFCs)

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Journal of rare Earths 2024年第10期42卷 1903-1911页

作者： Ahmed h.Ibrahim Yehia M.Abbas h.A.Ayoub Marwa h.Ali Mustafa Aldoori Materials Science Laboratory Physics DepartmentFaculty of ScienceSuez Canal University41522IsmailiaEgypt Ministry of high.r.Education and Scientific research Aliraqia University10011BaghdadIraq

h.r.in,we report the synthesis of a Dy-Gd co-doped cubic phase-stabilized Bi_(2)O_(3) solid electrolyte system via solid-state processing under atmosph.r.c *** with Dy^(3+) and Gd^(3+) has been observed to significantly enhance the densification process during sintering for stabilization purposes,th.r.by improving the electrical properties of δ-Bi_(2)O_(3)-type *** synthesized ceramics were ch.r.cterized using X-ray diffraction(XrD),field emission scanning electron microscopy-energy dispersive X-ray spectroscopy(FESEM-EDX),th.r.al gravimetry/differential th.r.al analysis(TG/DTA),and the four-point probe technique(4PPT).XrD analysis reveals that the samples Bi_(1-x-y)Gd_(x)Dy_(y)O_(1.5)(y=0.05/x=0.05,0.10,0,15,and 0.20,and x=0.05/y=0.10,0.15,and 0.20) exhibit a stable face-centered cubic δ-phase and a mixed-phase crystallographic *** XrD analysis of the stabilized δ-phase suggests that the prepared oxides show a face-centered cubic(FCC) structure with a space group of *** micrographs reveal that the composition Bi_(0.90)Gd_(0.05)Dy_(0.05)O_(1.5) has no significant ***,an evident increase in the pore formation is observed as the amount of Gd_(2)O_(3) increases until it reaches 20%.This finding suggests that dense pellets are formed during the sintering process at 900-1000℃.The DTA analyses were performed to verify the phase stability,which agrees with the XrD *** electrochemical performance of the synthesized Dy-Gd co-doped Bi_(2)O_(3)solid electrolyte system was evaluated and analyzed in detail by using the electrochemical impedance spectroscopy(EIS) technique,Based on EIS and conductivity measurements,Bi_(0.75)Gd_(0.20)Dy_(0.05)O_(1.5) exhibits the lowest activation energy of 0.519 eV and the highest conductivity value of 0.398 S/cm at 627℃compared to the oth.r.samples;this composition can be used as a solid electrolyte for intermediatetemperature solid oxide fuel cells(SOFCs).

关键词： Solid oxide fuel cells(SOFCs) rare earths Solid-state processing rietveld Fast Fourier transform(FFT) Electrochemical impedance spectroscopy(EIS)

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Multidimensional images and aberrations in STEM

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Chinese Physics B 2024年第9期33卷 68-74页

作者： Eric r.hoglund Andrew r.Lupini Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN 37831United States

recent advances in scanning transmission electron microscopy(STEM)have led to increased development of multidimensional STEM imaging modalities and novel image reconstruction *** interest arises because the main electron lens in a modern transmission electron microscope usually has a diffraction-space information limit that is significantly better than the real-space resolution of the same *** state-of-affairs is sometimes sh.r.d by oth.r.scattering methods in modern physics and contributes to a broader excitement surrounding multidimensional techniques that scan a probe while recording diffraction-space images,such as ptychography and scanning nano-beam ***,the contrasting resolution in the two spaces raises the question as to what is limiting their effective ***,we examine this paradox by considering the effects of aberrations in both image and diffraction planes,and likewise separate the contributions of pre-and post-sample *** consideration provides insight into aberration-measurement techniques and might also indicate improvements for super-resolution techniques.

关键词： scanning transmission electron microscopy (STEM) aberrations

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不同结构AlGaN基深紫外发光二极管性能研究

不同结构AlGaN基深紫外发光二极管性能研究

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作者： ALMAZrOI SALWA SAAD h 北京化工大学

学位级别：硕士

基于AlGaN材料的深紫外发光二极管(DUV LED)具有体积小、能耗低、工作电流小、亮度高和发光响应速度快等优点,发光具有很强的杀菌效果,是汞灯的理想替代品,广泛地用于生物研究和污水处理领域。同时也可以为生物实验室、实验用器具及医... 详细信息

基于AlGaN材料的深紫外发光二极管(DUV LED)具有体积小、能耗低、工作电流小、亮度高和发光响应速度快等优点,发光具有很强的杀菌效果,是汞灯的理想替代品,广泛地用于生物研究和污水处理领域。同时也可以为生物实验室、实验用器具及医院手术室、医疗器具等消毒,在微制造技术和环境科学领域也大有可为,而且还可以用于制造侦测有毒粒子的传感器。由于其很容易与晶体管和集成电路配套使用,是近几年来迅速崛起的半导体光电器件。然而由于材料极化特性、器件结构等一系列因素,导致器件的性能难以与同族材料制备的可见光LED比拟,严重阻碍了其产业化进程。针对上述难题,本论文设计构建了系列DUV LED器件结构,并采用APSYS软件,研究了有源区结构、电子阻挡层结构及p型区结构对器件性能的影响机理,并对器件结构进行了优化设计,获得了以下研究成果。(1)深入研究了有源区结构对器件性能的影响,研究发现在一定范围内增加量子阱(QW)和量子阱势垒(QB)层厚度可以提高载流子注入效率和辐射复合效率,提升内部量子效率(IQE)和总功率。然而,超过一定阈值后,由于量子限制stark效应,导致IQE下降。在本工作中,当QW和QB的厚度分别为3.50、10.00 nm时,器件性能最佳。I-V曲线显示,QW和QB厚度的增加,对器件开启电压几乎没有影响。该研究强调了材料组成、能带对齐和厚度在器件性能优化方面的重要性。优化QW和QB层的厚度可以极大地提高内部量子效率(IQE)和LED总功率。(2)探讨了超晶格电子阻挡层(SL-EBL)对AlGaN DUV LED性能的影响。深入研究了SL-EBL厚度对器件功能的影响,揭示了结构参数和LED性能之间微妙的关系。研究表明,SL-EBL厚度的变化对AlGaN DUV LED的效率有重大影响,随着SL-EBL厚度的增加,IQE和总LED功率均呈现出一致的降低。在所有结构中,较薄的SL-EBL厚度为1.00 nm时可实现最佳性能。此外,分析还探讨了SL-EBL结构和不同铝(Al)组分对SL-EBL性能的影响。对带隙能量的检查显示,较大的SL-EBL层导致导带和价带边缘发生显著变化,表明载流子限制增强,载流子迁移性降低。通过优化SL-EBL结构,可以达到更高的IQE,达到68.37%,强调了精心设计和组成在提高LED性能中的重要性。(3)研究探讨了p型层内Al化合物浓度的变化对器件特性的影响。审查了AlGaN DUV LED的Al比例与效率之间的相关性,以及它们各自的厚度。在优化Al浓度之后,确定了7).(6./7).(6.的配置,第一层厚度为10 nm,第二层厚度为10 nm,可以实现72.12%的内部量子效率(IQE)。该配置在注入电流为500 A/m时,还可实现144.24 W/m的输出功率。

关键词： AlGaN 发光二极管有源区 EBL AlGaN器件结

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