Quark Potential in a Quark-Meson Plasma

We investigate quark potential by considering meson exchanges in the two flavor Nambu--Jona-Lasinio model at finite temperature and density. There are two kinds of oscillations in the chiral restoration phase, one is the Friedel oscillation due to the sharp quark Fermi surface at high density, and the other is the Yukawa oscillation driven by the complex meson poles at high temperature. The quark-meson plasma is strongly coupled in the temperature region $1\le T/T_c \lesssim 3$ with $T_c$ being the critical temperature of chiral phase transition. The maximum coupling in this region is located at the critical point.Comment: 8 pages and 8 figure

Transport-theoretical Description of Nuclear Reactions

In this review we first outline the basics of transport theory and its recent generalization to off-shell transport. We then present in some detail the main ingredients of any transport method using in particular the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) implementation of this theory as an example. We discuss the potentials used, the ground state initialization and the collision term, including the in-medium modifications of the latter. The central part of this review covers applications of GiBUU to a wide class of reactions, starting from pion-induced reactions over proton and antiproton reactions on nuclei to heavy-ion collisions (up to about 30 AGeV). A major part concerns also the description of photon-, electron- and neutrino-induced reactions (in the energy range from a few 100 MeV to a few 100 GeV). For this wide class of reactions GiBUU gives an excellent description with the same physics input and the same code being used. We argue that GiBUU is an indispensable tool for any investigation of nuclear reactions in which final-state interactions play a role. Studies of pion-nucleus interactions, nuclear fragmentation, heavy ion reactions, hyper nucleus formation, hadronization, color transparency, electron-nucleus collisions and neutrino-nucleus interactions are all possible applications of GiBUU and are discussed in this article.Comment: 173 pages, review article. v2: Text-rearrangements in sects. 2 and 3 (as accepted for publication in Physics Reports

Fabrication of a multilayer spiral coil by selective bonding, debonding and MEMS technologies

For the further miniaturization of integrated circuits, the integration of passive components on the chip is one approach. In DC-DC converter applications, the integration of the inductor with high inductivity is one problem. This paper addresses this problem by proposing a new technique for fabricating a multilayer spiral coil that is also useful as part of electromagnetic MEMS (Micro-Electro-Mechanical Systems) actuators. The multilayer coil is made by stacking separately fabricated coil layers and joining them with a selective bonding and debonding technique

Low-temperature wafer bonding using solid-liquid inter-diffusion mechanism

The low temperature joining of semiconductor substrates on wafer level by solid-liquid inter-diffusion bonding using the Cu/Ga and Au/In systems is investigated regarding the bonding parameters and their influence on bond interface properties. The focus is on temperature dependence and composition of interface. In the case of Cu/Ga bonding, a phase transition from CuGa2 to Cu9Ga4 was found to be primarily responsible for an increase in bonding strength. After the temperature treatment of 90°C, a shear strength of up to 90 MPa could be achieved. Furthermore, the combination of Au and In with composition ratios suitable for AuIn2 and AuIn intermetallic phase formation was investigated. In the case of AuIn shear strength, 96 MPa was achieved using a bonding temperature of 200°C

The biological actions of 11,12-epoxyeicosatrienoic acid in endothelial cells are specific to the R/S-enantiomer and require the G(s) protein

Cytochrome P450-derived epoxides of arachidonic acid [i.e., the epoxyeicosatrienoic acids (EETs)] are important lipid signaling molecules involved in the regulation of vascular tone and angiogenesis. Because many actions of 11,12-cis-epoxyeicosatrienoic acid (EET) are dependent on the activation of protein kinase A (PKA), the existence of a cell-surface G(s)-coupled receptor has been postulated. To assess whether the responses of endothelial cells to 11,12-EET are enantiomer specific and linked to a potential G protein-coupled receptor, we assessed 11,12-EET-induced, PKA-dependent translocation of transient receptor potential (TRP) C6 channels, as well as angiogenesis. In primary cultures of human endothelial cells, (+/-)-11,12-EET led to the rapid (30 seconds) translocation a TRPC6-V5 fusion protein, an effect reproduced by 11(R),12(S)-EET, but not by 11(S),12(R)-EET or (+/-)-14,15-EET. Similarly, endothelial cell migration and tube formation were stimulated by (+/-)-11,12-EET and 11(R),12(S)-EET, whereas 11(S),12(R)-EET and 11,12-dihydroxyeicosatrienoic acid were without effect. The effects of (+/-)-11,12-EET on TRP channel translocation and angiogenesis were sensitive to EET antagonists, and TRP channel trafficking was also prevented by a PKA inhibitor. The small interfering RNA-mediated downregulation of G(s) in endothelial cells had no significant effect on responses stimulated by vascular endothelial growth or a PKA activator but abolished responses to (+/-)-11,12-EET. The downregulation of G(q)/11 failed to prevent 11,12-EET-induced TRPC6 channel translocation or the formation of capillary-like structures. Taken together, our results suggest that a G(s)-coupled receptor in the endothelial cell membrane responds to 11(R),12(S)-EET and mediates the PKA-dependent translocation and activation of TRPC6 channels, as well as angiogenesis

Influence of test speed on the bonding strength of glass frit bonded wafers

Wafer bonding is a key technology in the manufacturing of micro electro mechanical systems (MEMS). It describes various techniques of joining two wafers with or without thin intermediate layers on industrial scale. Thereby, glass frit bonding is used in a wide range of applications, especially for the encapsulation of surface mechanical sensors like gyroscopes and acceleration sensors. The strength of the bonded interface directly affects the reliability of glass frit bonded MEMS devices. Therefore, it has to be detemined experimentally. The fracture toughness and the shear strength are suitable values to characterize the bonding strength. They enable the comparison of different bonding technologies and process parameters during bonding as well as an estimation of lifetime for the whole microsystem. Because of the requirements of quality control during the manufacturing of micro systems, a large number of MEMS devices and test structures have to be characterized. To optimize the yield and provide adequate and reliable material properties, the influence of the testing speed on the micro chevron measurement and the shear test has to be analyzed

Structure and thermoelectric properties of PbTe films deposited by thermal evaporation method

Lead telluride (PbTe) thin films have been deposited on SiO2 substrate using thermal evaporation method. The structure of the films was found to have a face-centered cubic (fcc) with predominant grain growth in the (200) direction for both as-deposited and annealed samples up to 350 °C in vacuum for 1 h. The in-plain electrical resistivity and Hall measurements via van der Pauw method as a function of annealed temperatures were measured. It was found that increasing the annealing temperature led to increase in grain size, which in turn caused decrease of electrical resistivity and increase of Seebeck coefficient. The high power factor of 141.0 μWm-1K-2 was obtained for the annealed samples at 350 °C in vacuum for 1 h

Multi-wafer bonding technology for the integration of a micromachined Mirau interferometer

The paper presents the multi-wafer bonding technology as well as the integration of electrical connection to the z-scanner wafer of the micromachined array-type Mirau interferometer. A Mirau interferometer, which is a key-component of optical coherence tomography (OCT) microsystem, consists of a microlens doublet, a MOEMS Z-scanner, a focus-adjustment spacer and a beam splitter plate. For the integration of this MOEMS device heterogeneous bonding of Si, glass and SOI wafers is necessary. Previously, most of the existing methods for multilayer wafer bonding require annealing at high temperature, i.e., 1100 degrees C. To be compatible with MEMS devices, bonding of different material stacks at temperatures lower than 400 degrees C has also been investigated. However, if more components are involved, it becomes less effective due to the alignment accuracy or degradation of surface quality of the not-bonded side after each bonding operation. The proposed technology focuses on 3D integration of heterogeneous building blocks, where the assembly process is compatible with the materials of each wafer stack and with position accuracy which fits optical requirement. A demonstrator with up to 5 wafers bonded lower than 400 degrees C is presented and bond interfaces are evaluated. To avoid the complexity of through wafer vias, a design which creates electrical connections along vertical direction by mounting a wafer stack on a flip chip PCB is proposed. The approach, which adopts vertically-stacked wafers along with electrical connection functionality, provides not only a space-effective integration of MOEMS device but also a design where the Mirau stack can be further integrated with other components of the OCT microsystem easily

Mechanical characterization of glass frit bonded wafers

Wafer bonding is a key technology in the manufacturing of microelectronic and micromechanical systems on industrial scale. Especially glass frit bonding is often used for t he encapsulation of MEMS devices on wafer level. To ensure the reliability of these bonds and to prevent critical failure of the systems, characteristic mechanical properties of the bonded interface are required. The fracture toughness and the shear strength are suitable values to characterize the bonding strength and can be determined by micro chevron and shear testing. They depend on the bonding parameters as well as the test speed. Due to the correlation between measured bonding strength and test speed a maximum test speed has to be identified to obtain reliable failure criteria regarding the fracture toughness and the shear strength

Vertical integration of array-type miniature interferometers at wafer level by using multistack anodic bonding

In this work, vertical integration of miniaturized array-type Mirau interferometers at wafer level by using multi-stack anodic bonding is presented. Mirau interferometer is suitable for MEMS metrology and for medical imaging according to its vertical-, lateral- resolutions and working distances. Miniaturized Mirau interferometer can be a promising candidate as a key component of an optical coherence tomography (OCT) system. The miniaturized array-type interferometer consists of a microlens doublet, a Si-based MEMS Z scanner, a spacer for focus-adjustment and a beam splitter. Therefore, bonding technologies which are suitable for heterogeneous substrates are of high interest and necessary for the integration of MEMS/MOEMS devices. Multi-stack anodic bonding, which meets the optical and mechanical requirements of the MOEMS device, is adopted to integrate the array-type interferometers. First, the spacer and the beam splitter are bonded, followed by bonding of the MEMS Z scanner. In the meanwhile, two microlenses, which are composed of Si and glass wafers, are anodically bonded to form a microlens doublet. Then, the microlens doublet is aligned and bonded with the scanner/spacer/beam splitter stack. The bonded array-type interferometer is a 7- wafer stack and the thickness is approximately 5mm. To separate such a thick wafer stack with various substrates, 2-step laser cutting is used to dice the bonded stack into Mirau chips. To simplify fabrication process of each component, electrical connections are created at the last step by mounting a Mirau chip onto a flip chip PCB instead of through wafer vias. Stability of Au/Ti films on the MEMS Z scanner after anodic bonding, laser cutting and flip chip bonding are discussed as well