Sökning: "Three dimensional"

Visar resultat 6 - 10 av 1869 avhandlingar innehållade orden Three dimensional.

  1. 6. Three-dimensional structured carbon foam : synthesis and applications

    Författare :Ngoc Tung Pham; Jyri-Pekka Mikkola; Krisztian Kordas; William Siljebo; Dmitry Yu. Murzin; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Carbon foam; melamine foam; absorbent; water purification; heterogeneous catalyst; catalyst support; SpinChem®; rotating bed reactor; water electrolysis; energy conversion;

    Sammanfattning : Recently, due to the unique properties and structures such as large geometric surface area, electrical conductivity and light weight, 3D structured carbon materials have been attracting extensive attention from scientists. Moreover, the materials, which can provide well-defined pathways for reactants to easily access active sites, are extremely useful for energy conversion as well as environmental and catalysis applications. LÄS MER

  3. 7. Three-dimensional Finite Element Computation of Eddy Currents in Synchronous Machines

    Författare :Marguerite Touma Holmberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; synchronous machines; finite element method; eddy currents; three-dimensional;

    Sammanfattning : The thesis deals with the computation of eddy-current losses in the end regions of synchronous machines. Various magnetic and electric vector potential formulations of three-dimensional eddy-current problems are investigated. The equations are discretized by the finite element method with nodal or edge finite elements. LÄS MER

  4. 8. Flash Diffractive Imaging in Three Dimensions

    Författare :Tomas Ekeberg; Janos Hajdu; Keith Nugent; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray; diffraction; mimivirus; three dimensional; phase retrieval; EMC; manifold embedding; CXI; FEL; free-electron laser; single particle; Physics with specialization in Biophysics; Fysik med inriktning mot biofysik;

    Sammanfattning : During the last years we have seen the birth of free-electron lasers, a new type of light source ten billion times brighter than syncrotrons and able to produce pulses only a few femtoseconds long. One of the main motivations for building these multi-million dollar machines was the prospect of imaging biological samples such as proteins and viruses in 3D without the need for crystallization or staining. LÄS MER

  5. 9. Three-Dimensional Computation of Eddy Currents in End regions of Synchronous Generators

    Författare :Marguerite Touma; Sonja Lundmark; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; anisotropic; non-linear; conductor; eddy current; formulation; coil; source; saturated; finite element method; turbogenerator; three-dimensional; potential; laminated; steady state; hydrogenerator; winding;

    Sammanfattning : .... LÄS MER

  7. 10. Three-dimensional ultrasound studies of normal and abnormal ovaries

    Författare :Ligita Jokubkiene; gynekologisk och prenatal ultraljudsdiagnostik Obstetrisk; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; ovary; ovarian follicle; ovarian neoplasms; ultrasonography; three-dimensional imaging; Doppler ultrasound imaging; vascular morphology;

    Sammanfattning : The aims of this work were: 1) to estimate the number of follicles, ovarian volume and power Doppler vascular indices and their changes with age using three-dimensional (3D) transvaginal grey-scale and power Doppler ultrasound in asymptomatic women of fertile age either with natural menstrual cycles or using combined oral contraceptives, and 2) to determine whether tumour vascularity, assessed by 3D power Doppler ultrasound, can help discriminate between benign and malignant ovarian tumours. A group of 303 gynaecologically asymptomatic women, aged 20–39 years with normal menstrual cycles (NMC) and another group of 213 women aged 20–39 years using combined oral contraceptives (COC) were examined using two-dimensional (2D) and 3D transvaginal ultrasound once between cycle day 4 and 8. LÄS MER