Sökning: "Helium"

Visar resultat 21 - 25 av 124 avhandlingar innehållade ordet Helium.

  1. 21. Heavy helium isotopes : a comprehensive investigation of ⁸He and its unbound subsystem ⁷He

    Författare :Mikael Meister; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; breakup reactions; angular distributions; exotic nuclei; electromagnetic dissociation; 8He; 7He; invariant mass spectra; nuclear structure;

    Sammanfattning : .... LÄS MER

  3. 22. Novel RF MEMS Switch and Packaging Concepts

    Författare :Joachim Oberhammer; KTH; []
    Nyckelord :0-level packaging; adhesive bonding; BCB; benzocyclobutene; bond strength; contact printing; film actuator; glass lid encapsulation; glass lid packaging; helium leak test; hermetic packaging; hermeticity; high isolation switch; low stress silicon nitride; low volt; TECHNOLOGY; TEKNIKVETENSKAP;

    Sammanfattning : Radio-frequency microelectromechanical systems (RF~MEMS) are highly miniaturized devices intended to switch, modulate, filter or tune electrical signals from DC to microwave frequencies. The micromachining techniques used to fabricate these components are based on the standard clean-room manufacturing processes for high-volume integrated semiconductor circuits. LÄS MER

  4. 23. The Radio Frequency Single-Electron Transistor: Noise Properties and its Potential for Detecting Electrons on Helium

    Författare :Serguei Kafanov; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; single electron transistor; Coulomb blockade; SET; radio;

    Sammanfattning : In this thesis the noise in the single electron transistor (SET) has been investigated.The charge sensitivity for the radio frequency single electron transistor(RF-SET) was measured. The demonstrated result is better than the previouslybest reported value both at 40 mK, and at 4.2 K. LÄS MER

  5. 24. Electron-transfer processes in fast ion-atom collisions

    Författare :Kristian Støchkel; Henning Schmidt; Henrik Cederquist; Andreas Wolf; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Electron transfer processes fast ion atom collisions hydrogen helium; Atomic and molecular physics; Atom- och molekylfysik;

    Sammanfattning : The subject of this thesis is experimental studies of electron-transfer processes in ion-atom collisions at velocities significantly higher than typical orbital velocities of electrons in bound states of atoms or molecules. The experimental technique applied combines the high beam intensity of heavy-ion storage rings with a supersonic gas-jet target equipped with a recoil-ion-momentum spectrometer. LÄS MER

  7. 25. Why Faster is Better : On Minor Actinide Transmutation in Hard Neutron

    Författare :Daniel Westlén; Jan Wallenius; Marc Delpech; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; nuclear physics; nuclear engineering; Atomic physics; Atomfysik;

    Sammanfattning : In this thesis, options for efficient transmutation of transuranium elements are discussed. The focus is on plutonium, americium and curium mainly because of their long-term contribution to the radiotoxicity of spent nuclear fuel. Two innovative helium-cooled core designs are proposed, dedicated to the transmutation of actinides. LÄS MER