32,881 research outputs found
Transient and steady-state shear banding in a lamellar phase as studied by Rheo-NMR
Flow fields and shear-induced structures in the lamellar (L-alpha) phase of the system triethylene glycol mono n-decyl ether (C10E3)/water were investigated by NMR velocimetry, diffusometry, and H-2 NMR spectroscopy. The transformation from multilamellar vesicles (MLVs) to aligned planar lamellae is accompanied by a transient gradient shear banding. A high-shear-rate band of aligned lamellae forms next to the moving inner wall of the cylindrical Couette shear cell while a low-shear-rate band of the initial MLV structure remains close to the outer stationary wall. The band of layers grows at the expense of the band of MLVs until the transformation is completed. This process scales with the applied strain. Wall slip is a characteristic of the MLV state, while aligned layers show no deviation from Newtonian flow. The homogeneous nature of the opposite transformation from well aligned layers to MLVs via an intermediate structure resembling undulated multilamellar cylinders is confirmed. The strain dependence of this transformation appears to be independent of temperature. The shear diagram, which represents the shear-induced structures as a function of temperature and shear rate, contains a transition region between stable layers and stable MLVs. The steady-state structures in the transition region show a continuous change from layer-like at high temperature to MLV-like at lower temperature. These structures are homogeneous on a length scale above a few micrometers
Metrology of EUV Masks by EUV-Scatterometry and Finite Element Analysis
Extreme ultraviolet (EUV) lithography is seen as a main candidate for
production of future generation computer technology. Due to the short
wavelength of EUV light (around 13 nm) novel reflective masks have to be used
in the production process. A prerequisite to meet the high quality requirements
for these EUV masks is a simple and accurate method for absorber pattern
profile characterization. In our previous work we demonstrated that the Finite
Element Method (FEM) is very well suited for the simulation of EUV
scatterometry and can be used to reconstruct EUV mask profiles from
experimental scatterometric data. In this contribution we apply an indirect
metrology method to periodic EUV line masks with different critical dimensions
(140 nm and 540 nm) over a large range of duty cycles (1:2, ..., 1:20). We
quantitatively compare the reconstructed absorber pattern parameters to values
obtained from direct AFM and CD-SEM measurements. We analyze the reliability of
the reconstruction for the given experimental data. For the CD of the absorber
lines, the comparison shows agreement of the order of 1nm. Furthermore we
discuss special numerical techniques like domain decomposition algorithms and
high order finite elements and their importance for fast and accurate solution
of the inverse problem.Comment: Photomask Japan 2008 / Photomask and Next-Generation Lithography Mask
Technology X
Measurement of spark probability of GEM detector for CBM muon chamber (MUCH)
The stability of triple GEM detector setups in an environment of high
energetic showers is studied. To this end the spark probability in a shower
environment is compared to the spark probability in a pion beam.Comment: 5 pages, 10 figure
Rigorous FEM-Simulation of EUV-Masks: Influence of Shape and Material Parameters
We present rigorous simulations of EUV masks with technological imperfections
like side-wall angles and corner roundings. We perform an optimization of two
different geometrical parameters in order to fit the numerical results to
results obtained from experimental scatterometry measurements. For the
numerical simulations we use an adaptive finite element approach on irregular
meshes. This gives us the opportunity to model geometrical structures
accurately. Moreover we comment on the use of domain decomposition techniques
for EUV mask simulations. Geometric mask parameters have a great influence on
the diffraction pattern. We show that using accurate simulation tools it is
possible to deduce the relevant geometrical parameters of EUV masks from
scatterometry measurements.
This work results from a collaboration between Advanced Mask Technology
Center (AMTC, mask fabrication), Physikalisch-Technische Bundesanstalt (PTB,
scatterometry), Zuse Institute Berlin (ZIB), and JCMwave (numerical
simulation).Comment: 8 pages, 8 figures (see original publication for images with a better
resolution
Biomarkers in Posttraumatic Stress Disorder: Overview and Implications for Future Research
PTSD can develop in the aftermath of traumatic incidents like combat, sexual abuse, or life threatening accidents. Unfortunately, there are still no biomarkers for this debilitating anxiety disorder in clinical use. Anyhow, there are numerous studies describing potential PTSD biomarkers, some of which might progress to the point of practical use in the future. Here, we outline and comment on some of the most prominent findings on potential imaging, psychological, endocrine, and molecular PTSD biomarkers and classify them into risk, disease, and therapy markers. Since for most of these potential PTSD markers a causal role in PTSD has been demonstrated or at least postulated, this review also gives an overview on the current state of research on PTSD pathobiology
Study of the characteristics of GEM detectors for the future FAIR experiment CBM
Characteristics of triple GEM detector have been studied systematically. The
variation of the effective gain and energy resolution of GEM with variation of
the applied voltage has been measured with Fe55 X-ray source for different gas
mixtures and with different gas flow rates. Long-term test of the GEM has also
been performed.Comment: 2 Pages, 6 figure
Recommended from our members
Identification and characterization of a novel extracellular matrix protein nephronectin that is associated with integrin alpha8beta1 in the embryonic kidney.
The epithelial-mesenchymal interactions required for kidney organogenesis are disrupted in mice lacking the integrin alpha8beta1. None of this integrin's known ligands, however, appears to account for this phenotype. To identify a more relevant ligand, a soluble integrin alpha8beta1 heterodimer fused to alkaline phosphatase (AP) has been used to probe blots and cDNA libraries. In newborn mouse kidney extracts, alpha8beta1-AP detects a novel ligand of 70-90 kD. This protein, named nephronectin, is an extracellular matrix protein with five EGF-like repeats, a mucin region containing a RGD sequence, and a COOH-terminal MAM domain. Integrin alpha8beta1 and several additional RGD-binding integrins bind nephronectin. Nephronectin mRNA is expressed in the ureteric bud epithelium, whereas alpha8beta1 is expressed in the metanephric mesenchyme. Nephronectin is localized in the extracellular matrix in the same distribution as the ligand detected by alpha8beta1-AP and forms a complex with alpha8beta1 in vivo. Thus, these results strongly suggest that nephronectin is a relevant ligand mediating alpha8beta1 function in the kidney. Nephronectin is expressed at numerous sites outside the kidney, so it may also have wider roles in development. The approaches used here should be generally useful for characterizing the interactions of novel extracellular matrix proteins identified through genomic sequencing projects
- …