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入们篇：数码相机的焦距

数码 2004年第9期 180-182页

作者：李琦 m4

对大多数购买数码相机的消费者来说，最关心的相机指标除了像素以外，镜头的变焦能力应该是另外一个不容置疑的答案。大变焦镜头的数码相机似乎一直很受欢迎，10×甚至更大变焦能力的数码相机更受到一些摄影爱好者的追捧。不过文物古迹... 详细信息

对大多数购买数码相机的消费者来说，最关心的相机指标除了像素以外，镜头的变焦能力应该是另外一个不容置疑的答案。大变焦镜头的数码相机似乎一直很受欢迎，10×甚至更大变焦能力的数码相机更受到一些摄影爱好者的追捧。不过文物古迹产回来，我们在使用数码相机的过程中，真正对数码相机的变焦物尽其用了吗？

关键词：数码相机焦距变焦镜头摄影爱好者像素购买变焦能力对数指标

冠状动脉旁路移植术前对环氧化酶-1抑制性的评估：血小板聚集率与患者自测的对比研究

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麻醉与镇痛 2011年第3期7卷 32-38页

作者： Niels Rahe-meyer, mD, PhD michael Winterhalter, m4 Julia Hartmann Albert Pattison Hartmut Hecker Andreas Calatzis, mD Cristina Solomon, mD 曹晖(译) Department of Anesthesiology Hannover Medical School Hannover Germany Hart Biologicals Hartlepool UK University Hospital munich Munich Germany Institute for Biometry Hannover Medical School Hannover Germany University Hospital munich Munich Germany Department of Hemostasis and Transfusion medicine University Hospital Munich Munich Germany 不详

背景抗血小板治疗导致的血小板功能减退可产生围手术期出血，数项对手术前5日内摄入阿司匹林的影响研究结果不一，有的认为摄入阿司匹林会增加围手术期输血量，而有的认为并无显著影响。本项研究的目的在于对比患者自身报告服药情况与... 详细信息

背景抗血小板治疗导致的血小板功能减退可产生围手术期出血，数项对手术前5日内摄入阿司匹林的影响研究结果不一，有的认为摄入阿司匹林会增加围手术期输血量，而有的认为并无显著影响。本项研究的目的在于对比患者自身报告服药情况与血小板功能测定两种方法评估阿司匹林摄入对围手术期输血需求的影响。方法在一项前瞻性研究中，对100例行冠状动脉旁路移植术的患者，术前5日阿司匹林的摄入进行标准化问卷调查。另外，使用multiplate血小板功能分析仪测定花生四烯酸介导的全血血小板聚集率。结果23例手术前5日内服用阿司匹林的患者中有11例血小板聚集功能异常，77例手术前未服用阿司匹林的患者中有9例血小板功能异常。服用与未服用阿司匹林的患者相比，手术后24小时内胸管引流量及红细胞输注量无显著差别。手术前血小板聚集功能异常的患者（〈51U）所需的血小板输注量（1．1U）显著高于血小板聚集功能正常的患者（0．3U，P=0．001）。结论本研究结果显示全血花生四烯酸诱导血小板聚集率对于血小板相关的凝血功能异常及血小板输注量的预测优于患者自身报告阿司匹林的摄入情况。

关键词：冠状动脉旁路移植术血小板聚集率手术前环氧化酶-1 患者血小板聚集功能异常评估血小板功能分析仪

Frequency-dependent viscoelasticity effects on the wave attenuation performance of multi-layered periodic foundations

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 407-424页

作者： m.SAFI m.VAKILIFARD m.J.mAHmOODI Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of mechanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(LPFs)are numerically examined for their responses to longitudinal and transverse modes in the time and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,comprising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber materials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is modeled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the complex dispersion curves and the identification of the band gaps(BGs),the simulations of wave transmission in the time and frequency domains are performed using the COmSOL *** parametric studies evaluate the effects of the rubber viscoelasticity models on the dispersion curves and the wave transmission for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-mode damping is more sensitive to the viscoelasticity model than its longitudinal *** 6-layer unit-cell LPF exhibits the lowest BG,ranging from 4.8 Hz to 6.5 Hz.

关键词： layered metamaterial periodic foundation complex dispersion curve wave transmission diagram

Engineering of efficient visible light photocatalysts:Ti_(1-x+y)Cu_(x)La_(y)O_(2)(x=0.03;y=0,0.005,0.01) compositions

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Journal of Rare Earths 2024年第3期42卷 497-505,I0003页

作者： S.m.Yakout A.m.Youssef Inorganic Chemistry Department National Research Centre(NRC)El Buhouth StDokkiCairo12622Egypt

In dye-photocatalysis, widening the wavelengths absorption range of catalysts as well as aborting the recombination of the photoexcited charge carriers(electrons-holes pairs) are of paramount *** the current study, we report the photocatalytic characteristics of four compositions composed of TiO_(2),Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders for two harmful dyes(Congo red and methylene blue). The X-ray diffraction technique verified the configuration of mixed anatase and rutile phases in pure TiO_(2)and Ti_(0.97)Cu_(0.03)O_(2)powders while Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders possess anatase phase only. The changes of the band gap structure and dimensions of the unit cell volume of TiO_(2)confirm the substitution of Ti^(4+)sites by Cu^(2+)and La^(3+)ions. Remarkable widening of wavelengths absorption with formation of long absorption tails were found in TiO_(2)(3.13 e V) through insertion of La^(3+)plus Cu^(2+)ions. Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)samples exhibit a visible light band gap of 2.3 and 2.7 e V, respectively. Based on SEm images, incorporation of Cu^(2+)and La^(3+)ions influences the surface morphology of TiO_(2). The resulting Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders present enhanced photocatalytic activity towards Congo red dye degradation compared to pure one under natural solar spectrum. The best Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst exhibits superior photocatalytic activity of 96% for 10 ppm CR dye in 20 min as well as above average photocatalytic efficiency of 63% for 30 ppm CR dye in 120 min. As well, it showed acceptable photodegradation activity of 52% for 30 ppm mB solution in 140 min of sunlight irradiation. The heightened photodegradation efficiency of Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst can be clarified in terms of higher ch

关键词： Semiconductor TiO_(2) Rare earths Congo red methylene blue Solar spectrum Photodegradation

Nonlinear dynamic modeling of planar moving Timoshenko beam considering non-rigid non-elastic axial effects

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 479-496页

作者： m.ABBASI GAVARI m.R.HOmAEINEZHAD Faculty of mechanical Engineering K.N.Toosi University of TechnologyTehran 19991-43344Iran

Due to the importance of vibration effects on the functional accuracy of mechanical systems,this research aims to develop a precise model of a nonlinearly vibrating single-link mobile flexible *** manipulator consists of an elastic arm,a rotary motor,and a rigid carrier,and undergoes general in-plane rigid body motion along with elastic transverse *** accurately model the elastic behavior,Timoshenko’s beam theory is used to describe the flexible arm,which accounts for rotary inertia and shear deformation *** applying Newton’s second law,the nonlinear governing equations of motion for the manipulator are derived as a coupled system of ordinary differential equations(ODEs)and partial differential equations(PDEs).Then,the assumed mode method(Amm)is used to solve this nonlinear system of governing equations with appropriate shape *** assumed modes can be obtained after solving the characteristic equation of a Timoshenko beam with clamped boundary conditions at one end and an attached mass/inertia at the *** addition,the effect of the transverse vibration of the inextensible arm on its axial behavior is *** the axial rigidity,the effect makes the rigid body dynamics invalid for the axial behavior of the ***,numerical simulations are conducted to evaluate the performance of the developed model,and the results are compared with those obtained by the finite element *** comparison confirms the validity of the proposed dynamic model for the *** to the mentioned features,this model can be reliable for investigating the system’s vibrational behavior and implementing vibration control algorithms.

关键词： planar moving Timoshenko beam non-rigid non-elastic axial effect as-sumed mode method(Amm) nonlinear motion analysis

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 543-562页

作者： H.m.FEIZABAD m.H.YAS Department of mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** Hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQm)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQm)

Enhanced quantum resources via two distant atom-cavity systems under the influence of atomic dissipation

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Communications in Theoretical Physics 2024年第2期76卷 62-73页

作者： m Setodeh Kheirabady m K Tavassoly m Rafeie E Ghasemian Laser and Optics Group Faculty of PhysicsYazd UniversityYazd 89195-741Iran Department of Electrical Engineering Faculty of Intelligent Systems Engineering and Data SciencePersian Gulf UniversityBushehrIran

Quantum resources such as entanglement and coherence are the holy grail for modern quantum technologies. Although the unwanted environmental effects tackle quantum information processing tasks, suprisingly these key quantum resources may be protected and even enhanced by the implementation of some special hybrid open quantum systems. Here, we aim to show how a dissipative atom-cavity-system can be accomplished to generate enhanced quantum *** do so, we consider a couple of dissipative cavities, where each one contains two effective two-level atoms interacting with a single-mode cavity field. In practical applications, a classical laser field may be applied to drive each atomic subsystem. After driving the system, a Bell-state measurement is performed on the output of the system to quantify the entanglement and coherence. The obtained results reveal that the remote entanglement and coherence between the atoms existing inside the two distant cavities are not only enhanced, but can be stabilized, even under the action of dissipation. In contrast, the local entanglement between two atoms inside each dissipative cavity attenuates due to the presence of unwanted environmental ***, the local coherence may show the same behavior as the remote ***, the system provides the steady state entanglement in various interaction regimes,particularly in the strong atom-cavity coupling and with relatively large detuning. more interestingly, our numerical analyses demonstrate that the system may show a memory effect due to the fact that the death and revival of the entanglement take place during the interaction. Our proposed model may find potential applications for the implementation of long distance quantum networks. In particular, it facilitates the distribution of quantum resources between the nodes of large-scale quantum networks for secure communication.

关键词： remote entanglement and coherence atomic dissipation steady state entanglement Bell-statemeasurement

Effects of multiple shapes for steady flow with transformer oil+Fe_(3)O_(4)+TiO_(2) between two stretchable rotating disks

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Applied mathematics and mechanics(English Edition) 2024年第2期45卷 373-388页

作者： m.RAHmAN m.TURKYILmAZOGLU Z.mUSHTAQ Department of mathematics Mirpur University of Science and TechnologyMirpur 10250Pakistan Department of mathematics Hacettepe UniversityBeytepeAnkara 06532Turkiye

In this study,we examine the effects of various shapes of nanoparticles in a steady flow of hybrid nanofluids between two stretchable rotating *** steady flow of hybrid nanofluids with transformer oil as the base fluid and Fe_(3)O_(4)+TiO_(2)as the hybrid nanofluid is *** shapes of Fe_(3)O_(4)+TiO_(2)hybrid nanofluids,including sphere,brick,blade,cylinder,and platelet,are *** shape exists in the same volume of a *** leading equations(partial differential equations(PDEs))are transformed to the nonlinear ordinary differential equations(ODEs)with the help of similarity *** system of equations takes the form of ODEs depending on the boundary conditions,whose solutions are computed numerically by the bvp4c mATLAB *** outputs are compared with the previous findings,and an intriguing pattern is discovered,such that the tangential velocity is increased for the rotation parameter,while it is decreased by the stretching values because of the lower *** the reaction rate parameter,the concentration boundary layer becomes shorter,and the activation energy component increases the rate at which mass transfers come to the higher disk but have the opposite effect on the bottom *** ranges of various parameters taken into account are Pr=6.2,Re=2,m=1.0,φ_(1)=φ_(2)=0.03,K=0.5,S=-0.1,Br=0.3,Sc=2.0,α_(1)=0.2,γ=0.1,E_(n)=2.0,and q=1.0,and the rotation factor K is within the range of 0 to 1.

关键词： transformer oil Brinkman number skin friction coefficient double rotating disk Nusselt number Sherwood number

Enhancement of coercivity,permeability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites for memory and high frequency devices

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Journal of Rare Earths 2024年第6期42卷 1128-1135,I0005页

作者： I.Sardar m.D.Hossain m.S.Sikder m.N.I.Khan m.R.Rahman Physics Discipline Khulna UniversityKhulna9208Bangladesh Department of Physics Khulna University of Engineering&TechnologyKhulna9203Bangladesh Department ofComputer Science and Engineering Northern University of Business&Technology KhulnaKhulna9100Bangladesh material Science Division Atomic Energy CentreDhaka1000Bangladesh

Spinel cubic ferrites have huge applications in me mory and high frequency *** the improvement of these modern devices,the magnetic coercivity,permeability,and dielectric properties of a ferrite are the important *** article focuses on improving the magnetic coercivity,magnetic permeability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites,where x=0.00,0.06,and *** X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),field emission scanning electron microscopy(FESEm),energy dispersive X-ray(EDX),vibrating sample magnetometer(VSm),and an impedance analyzer were used to characterize the structural,magnetic,and dielectric properties of the *** XRD patterns indicate the formation of spinel cubic structure of the samples with a secondary peak(EuFeO_(3))for Eu doped *** densities and porosities of the samples follow an inverse trend,where the doped samples’lattice parameters are increased with the increment of rare earth Eu *** FTIR analysis also proves the spinel cubic phase of the *** average grain size of the ferrites is obtained via FESEm images,and it is increased from 121 to 198 *** analysis confirms that doping of the Eu content also changes other hysteresis loop properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ***,the coercivity of the Eu doped samples is greater than that of the mother alloy(x=0.00).The EDX study shows that there is no impurity contamination in the *** permeability and dielectric measurements show an improved quality factor of the Eu-doped samples with low magnetic and dielectric *** dependent resistivity and impedance analysis also show the improved *** the observed properties of the samples,all the investigated ferrites might be strong candidates for potential applications in memory devices,magnetic sensors,and high frequency applications.

关键词： Ferrites Raree arths Coercivity Permeability EDX Resistivity