检索结果-南通市图书馆

Effects of varying Alx moles on structure and luminescence properties of ZnAl_(x)O_(1.5x+1):0.1 mol%tb^(3+)nanophosphors prepared using citrate sol-gel method

引用

Journal of Rare Earths 2023年第3期41卷 358-364,I0002页

作者： V.M.Maphiri l.t.melato M.R.Mhlongo t.t.Hlatshwayo t.E.Motaung l.F.Koao S.V.Motloung Department of Physics Sefako Makgatho Health Science UniversityP.O.Box 94Medunsa0204South Africa Department of Mathematics Non Destructive Testing and PhysicsVaal University of TechnologyAndries Potgieter BlvdVanderbijlpark1900South Africa Department of Physics University of PretoriaPretoria0002South Africa Department of Chemistry School of Science in the College of Science Engineering and TechnologyUniversity of South AfricaPreller StreetMuckleneuk RidgeCity of TshwaneP.O Box 392UNISA 0003South Africa Department of Chemistry Sefako Makgatho Health Science UniversityP.O.Box 94Medunsa0204South Africa Department of Physics University of the Free State(Qwaqwa Campus)Private Bag X13Phuthaditjhaba 9866South Africa Department of Chemical and Physical Sciences Walter Sisulu UniversityMthathaSouth Africa

Un-doped and ZnAl_(x)O_(1.5x+1):0.1 mol%tb^(3+)(ZAOt)nano-powders were synthesized via citrate sol-gel *** AIx moles were varied in the range of 0.25≤x≤*** X-ray powder diffraction(XRD)data reveal that for xthe prepared samples crystal structure consists of mixed phases of the cubic ZnAl_(2)O_(4) and hexagonal ZnO phases,while for x>1.5 the structure consists of single phase of cubic ZnAl_(2)O_(4).the Raman and Fourier-trans form infrared(FtIR)vibrational spectroscopy show the presence of vibrations emanating ZnAl_(2)O_(4) *** electron microscopy(SEM)and transmission electron microscopy(tEM)show the presence of irregular sphere at x>2.0 attributed to ZnAl_(2)O_(4).the photoluminescence(Pl)spectroscopy reveals emissions from both the host and tb^(3+)*** from tb^(3+)are observed at 382,414,439,458 nm and 489,545,585,621 nm,which were attributed to the^(5)D_(3)→^(7)F_(6,5,4,2) and ^(5^)D_(4)→^(7)F_(6,5,4,3),*** results confirm that the tb^(3+)occupation site depends on the Alx *** International Commission on Illumination(CIE)colour chromaticity shows that the emission colour can be tuned from blue to green by varying the AIx moles.

关键词： Citrate sol-gel ZnAl_(2)O_(4)/ZnO tb^(3+)-doped Al_(x)moles Photoluminescence Rare earths

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Beginning from the end:the presynaptic terminal as a pathomechanism hub in frontotemporal dementia and amyotrophic lateral sclerosis

引用

Neural Regeneration Research 2025年第11期20卷 3217-3218页

作者： laura Huggon Emma l.Clayton UK Dementia Research Institute at King’s College london LondonUK Department of Basic and Clinical Neuroscience Institute of Psychiatry Psychology&NeuroscienceKing’s College LondonLondonUK

Frontotemporal dementia and amyotrophic lateral sclerosis:Frontotemporal dementia(F t D)and amyo t rophic lateral sclerosis(AlS)are neurodegenerative diseases with significant overlapping *** these neurodegenerative diseases affect different neuronal populations(with FtD affecting neurons of the frontal and temporal lobes,and AlS affecting upper and lower motor neurons),these two diseases are complexly *** and AlS exist on a disease spectrum,with shared genetic causes,clinical presentations,and pathologies.

关键词： diseases amyotrophic sclerosis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Generation of brain vascular heterogeneity:recent advances from the perspective of angiogenesis

引用

Neural Regeneration Research 2025年第7期20卷 2013-2014页

作者： Nathanael J.lee Ryota l.Matsuoka Department of Neurosciences Lerner Research InstituteCleveland ClinicClevelandOHUSA Department of Molecular Medicine Cleveland Clinic Lerner College of MedicineCase Western Reserve UniversityClevelandOHUSA

Heterogeneous proper t i es of vascular endothelial cells in the brain:the brain displays large energy dynamics and consumption,and this high level of metabolic demands is fulfilled by a continuous supply of glucose and oxygen through its vascular *** vasculature consists of highly divergent blood vessel branches,giving rise to a dense network of capillaries that supply blood to all cells across the *** elaborated vascular network is thought to develop via angiogenesis,a process in which new blood vessels grow from pre-existing *** capillaries exhibit organotypic features distinct from other tissues and are formed primarily by two major endothelial cell(EC)types:those that form the semi-permeable blood-brain barrier(BBB)and those that develop highly permeable pores known as fenestrae(Matsuoka et al.,2022).the structural and functional differences between BBB and fenestrated vascular ECs represent a fundamental feature of brain vasculature and form the foundation for both brain function and homeostasis.

关键词： angiogenesis homeostasis network

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

the dynamic compensation temperature in a kinetic spin-5/2 Ising model on a hexagonal lattice

引用

Chinese Physics B 2013年第3期22卷 471-480页

作者： mt temizer Aysegl Ozkιlι Department of Physics Bozok University66200 YozgatTurkey Institute of Science Bozok University66200 YozgatTurkey

We present a study of the dynamic behavior of a two-sublattice spin-5/2 Ising model with bilinear and crystal-field interactions in the presence of a time-dependent oscillating external magnetic field on alternating layers of a hexagonal lattice by using the Glauber-type stochastic *** lattice is formed by alternate layers of spins σ=5/2 and S=5/*** employ the Glauber transition rates to construct the mean-field dynamic ***,we investigate the time variations of the average sublattice magnetizations to find the phases in the system and then the thermal behavior of the dynamic sublattice magnetizations to characterize the nature（first-or second-order） of the phase transitions and to obtain the dynamic phase transition（DPt） *** also study the thermal behavior of the dynamic total magnetization to find the dynamic compensation temperature and to determine the type of the dynamic compensation *** present the dynamic phase diagrams,including the dynamic compensation temperatures,in nine different *** phase diagrams contain seven different fundamental phases,thirteen different mixed phases,in which the binary and ternary combination of fundamental phases and the compensation temperature or the l-type behavior strongly depend on the interaction parameters.

关键词： kinetic Ising model dynamic phase transition dynamic compensation temperature

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

DIPOlE POlARIZAtION RElAXAtION AND MOlECUlAR StRUCtURE OF MAIN-AND SIDE-CHAIN lIQUID-CRYStAllINE POlYMERS

引用

Chinese Journal of Polymer Science 1996年第1期14卷 1-18页

作者： t.P.Stepanova l.l.Burshtein Institute of Macromolecular Compounds of Russian Academy of Sciences Bolshoy pr. 31 St. Petersburg 199004 RussiaInstitute of Macromolecular Compounds of Russian Academy of Sciences Bolshoy pr. 31 St. Petersburg 199004 Russia

Molecular mobility in thermotropic polyesters and side-chain polymers with different struc-ture of mesogens and spacers has been studied by dielectrical method in dilutesolutions. the results made it possible to establish the multiplicity of dielectric relaxationtransitions which reflects the small- and large-scale types of molecular motion. It was shownthat dielectric relaxation processes occurring in accordance with local mechanism (relaxationtimes 10^(-9)--10^(-7)s. and the activation energy 10--50kJ/mol) are due to the mobility of kineticchain elements of different length within a monomer units. It was found that the dielectricrelaxation process connected with a large-scale form of molecular motion (relaxation times10^(-5)--10^(-6)s. and the activation energy 100kJ/mol) did not depend on the molecular massbut was infiuenced by factors changing the conformational state of the macromolecule. It isestablished tha the cooperative reorientation mobility of associated mesogenic fragments isthe source of the large-scale process.

关键词： liquid crystal polymers Dielectric polarization Relaxation transitions Dilute solution Aggregation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Fluorescence quenching of eosin upon adsorption by colloidal silver mediated in aqueous solution and reverse micelles

引用

Chinese Journal of Chemistry 1996年第4期14卷 315-320页

作者： Zang, l Shen, t CHINESE ACAD SCI INST PHOTOG CHEMBEIJING 100101PEOPLES R CHINA

the optical effects of the adsorption of eosin on the colloidal sliver particle have been investigated in aqueous solutions. It was found that upon adsorption the fluorescence of eosin was effectively quenched. this was explained as the photoinduced interfacial electron transfer from the excited singlet state of eosin to the silver particle. Decreasing pH of the solution favors the adsorption of eosin and so enhances the fluorescence quenching. For comparison, the fluorescence quenching in reverse micelles was also investigated. the quenching behavior was much different from that mediated in aqueous solution. this was attributed to the unique microenvironment of reverse micelles.

关键词： photoinduced electron transfer eosin reverse micelle

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

the Isentropic Exponent of Single-Ionized Mono-Atomic Plasmas

引用

Plasma Science and technology 2012年第8期14卷 699-701页

作者： K.t.A.l.BURM PlasmAIX for Plasma Research Heimerik 472440 GeelBelgium

the isentropic exponent of single-ionized mono-atomic plasmas in thermal equilib- rium is studied. Its behavior as a function of the ionization degree and temperature is examined for argon and zinc plasmas at two pressures （1 bar and 1 mbar, 1 mPa and 1 Pa）, respectively. the results show that for the two sorts of plasma the isentropic exponent equals typically about 1.1-1.2 within a considerably wide range of the ionization degree （5%-80%）.

关键词： plasma modelling isentropic exponent

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

three-dimensional dynamics of supported pipes conveying fluid

引用

Acta Mechanica Sinica 2017年第6期33卷 1065-1074页

作者： l.Wang t.l.Jiang H.l.Dai Department of Mechanics Huazhong University of Science and Technology Wuhan 430074 China Hubei Key laboratory for Engineering Structural Analysis and Safety Assessment Wuhan 430074 China

this paper deals with the three-dimensional dynamics and postbuckling behavior of flexible supported pipes conveying fluid, considering flow velocities lower and higher than the critical value at which the buckling instability occurs. In the case of low flow velocity, the pipe is stable with a straight equilibrium position and the dynamics of the system can be examined using linear theory. When the flow velocity is beyond the critical value, any motions of the pipe could be around the postbuckling configuration(non-zero equilibrium position) rather than the straight equilibrium position, so nonlinear theory is required. the nonlinear equations of perturbed motions around the postbuckling configuration are derived and solved with the aid of Galerkin discretization. It is found, for a given flow velocity,that the first-mode frequency for in-plane motions is quite different from that for out-of-plane motions. However, the second-or third-mode frequencies for in-plane motions are approximately equal to their counterparts for out-of-plane motions, keeping almost constant values with increasing flow velocity. Moreover, the orientation angle of the postbuckling configuration plane for a buckled pipe can be significantly affected by initial conditions, displaying new features which have not been observed in the same pipe system factitiously supposed to deform in a single plane.

关键词： Pipe conveying fluid three-dimensional dynamics Instability Natural frequency Postbuckling configuration

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

How do quantum numbers generally vary in the adiabatic transformation of an ideal gas?

引用

Chinese Physics B 2011年第10期20卷 305-311页

作者： t. Yarman A. l. Kholmetskii Department of Engineering Okan UniversityAkfirat Istanbul Turkey & Savronik Eskisehir Turkey Department of Physics Belarus State University4 Nezavisimosti Avenue 220030 Minsk Belarus

We continue to analyse the known law of adiabatic transformation for an ideal gas PV5/3=Constant, where P isthe pressure and V is the volume, and following the approach of non-relativistic quantum mechanics which we suggested in a previous work （Yarman et al. 2010 Int. J. Phys. Sci. 5 1524）. We explicitly determine the constant for the general parallelepiped geometry of a container. We also disclose how the quantum numbers associated with molecules of an ideal gas vary through an arbitrary adiabatic transformation. Physical implications of the results obtained are discussed.

关键词： ideal gas adiabatic transformation non-relativistic quantum mechanics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

tuning the particle size,physical properties,and photocatalytic activity of Ag_(3)PO_(4)materials by changing the Ag^(+)/PO_(4)^(3-)ratio

引用

Chinese Physics B 2023年第3期32卷 561-568页

作者： Hung N M Oanh l t M Chung D P thang D V Mai V t Hang l t Minh N V Center for Nano Science and technology Hanoi National University of Education136 Xuan Thuy RoadCau Giay DistrictHanoi 100000Vietnam Department of Physics Hanoi National University of Education136 Xuan Thuy RoadCau Giay DistrictHanoi 100000Vietnam Hanoi University of Mining and Geology Duc Thang WardNorth Tu Liem DistrictHanoi 100000Vietnam Institute of Materials Science Vietnam Academy of Science and Technology18 Hoang Quoc VietHanoi 100000Vietnam Faculty of Basic Sciences Hanoi University of Natural Resources and Environment41 A Phu Dien RoadNorth Tu LiemHanoi 100000Vietnam

this study demonstrates the influence of the Ag^(+)/PO_(4)^(3-)ratio in precursor solution on the crystal structural formation,morphology,physical properties,and photocatalytic performance of a Ag_(3)PO_(4)photocatalyst that is fabricated,using a facile precipitation method,from AgNO_(3)and Na2HPO_(4)·12H_(2)*** material characterizations were carried out using x-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive x-ray spectroscopy(EDX),Brunauer–Emmett–teller(BEt)surface area,Fourier transform infrared(FtIR)absorption,Raman scattering,x-ray photoelectron spectroscopy(XPS),UV-vis absorption,and photoluminescence(Pl).the results show that Ag_(3)PO_(4)crystallizes better when the excess PO_(4)^(3-)content increases,and the lattice parameters decrease slightly,while the crystal diameter and the particle size *** change is also observed in the Raman scattering and FtIR spectra with the increase in the vibration frequency of the[PO_(4)]*** compression of the[PO_(4)]unit was also confirmed in the XPS spectra with the shift of P 2p peaks toward higher binding *** photocatalytic results showed that the samples synthesized from excess PO_(4)^(3-)solution exhibited higher photocatalytic performance compared to the sample with a Ag^(+)/PO_(4)^(3-)ratio of 3:1.A sample prepared from the precursor solution with a Ag^(+)/PO_(4)^(3-)ratio of 3:1.5 was optimal for RhB decomposition under both visible light and natural sunlight,completely decomposing 10 ppm RhB after 15 minutes of xenon lamp irradiation and after 60 minutes under solar light *** is attributed to the high crystallinity,small particle size and low electron–hole recombination rate of the sample.

关键词： morphology photocatalytic Ag^(+)/PO_(4)^(3-)ratio visible light

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：