ABSTRACT
We describe a search for gravitational waves from compact binaries with at least one component with mass $0.2$–$1.0 \, \mathrm{M}_\odot$ and mass ratio q ≥ 0.1 in Advanced Laser ...Interferometer Gravitational-Wave Observatory (LIGO) and Advanced Virgo data collected between 2019 November 1, 15:00 utc and 2020 March 27, 17:00 utc. No signals were detected. The most significant candidate has a false alarm rate of $0.2 \, \rm {yr}^{-1}$. We estimate the sensitivity of our search over the entirety of Advanced LIGO’s and Advanced Virgo’s third observing run, and present the most stringent limits to date on the merger rate of binary black holes with at least one subsolar-mass component. We use the upper limits to constrain two fiducial scenarios that could produce subsolar-mass black holes: primordial black holes (PBH) and a model of dissipative dark matter. The PBH model uses recent prescriptions for the merger rate of PBH binaries that include a rate suppression factor to effectively account for PBH early binary disruptions. If the PBHs are monochromatically distributed, we can exclude a dark matter fraction in PBHs $f_\mathrm{PBH} \gtrsim \, 0.6$ (at 90 per cent confidence) in the probed subsolar-mass range. However, if we allow for broad PBH mass distributions, we are unable to rule out fPBH = 1. For the dissipative model, where the dark matter has chemistry that allows a small fraction to cool and collapse into black holes, we find an upper bound fDBH < 10−5 on the fraction of atomic dark matter collapsed into black holes.
In this paper a novel solder-based die-to-die or wafer-to-wafer interconnect approach is introduced. This technique allows for microbump interconnects with different diameters on a single die and ...allows for pitch scaling down to 5μm A metal damascene process is used to create the metal pad layers for soldering. Solder μm bumps are created by semiadditive electroplating. After embedding the solder μbumps in a partially cured polymer, the wafer surface is planarized and the solder surface is exposed. This results in flat die surfaces of the die before bonding. Using a thermo-compression bonding process these flat surfaces can be aligned, the solder reacts with the metal pad to form a solder joint and the polymer can bond and cure to ensure a void less underfill layer for mechanical strength and increased reliability. The selection of suitable metals and polymers as well as the different process steps together with reliability data will be discussed in detail. Electrical yield and quality of bonding is demonstrated using imec 5μm pitch PTCU/W test vehicle for die to wafer bonding.
The conversion of
n-hexane and 2,2,4 triMe-pentane was studied at 723
K on a USY-zeolite (Si/Al: frame=30; bulk=2.7) in an electrobalance reactor with external recirculation. The influence of the ...coke content on the reaction paths involved in the conversion of paraffinic model components was evaluated. Coke formation from propylene and i-butene, the main olefinic products formed during the conversion of the two paraffinic model components, was investigated.
Under the conditions used, an increase in the molar H/C ratio of the products as a function of coke yield can be observed due to hydride transfer reactions with coke. Coke molecules cannot be considered as being inert with respect to the cracking reactions and their formation leads to the occurrence of reactions that can strongly influence the catalyst performance. In particular, the potential of coke molecules to form highly delocalized carbenium ions and their ability to act as hydride donor towards surface carbenium ions provides reaction paths to paraffinic reaction products.
The effect of coke is not identical for all the elementary reactions involved in the conversion of the paraffinic model components.
The Einstein Telescope (ET), the European project for a third-generation gravitational-wave detector, has a reference configuration based on a triangular shape consisting of three nested detectors ...with 10 km arms, where in each arm there is a `xylophone' configuration made of an interferometer tuned toward high frequencies, and an interferometer tuned toward low frequencies and working at cryogenic temperature. Here, we examine the scientific perspectives under possible variations of this reference design. We perform a detailed evaluation of the science case for a single triangular geometry observatory, and we compare it with the results obtained for a network of two L-shaped detectors (either parallel or misaligned) located in Europe, considering different choices of arm-length for both the triangle and the 2L geometries. We also study how the science output changes in the absence of the low-frequency instrument, both for the triangle and the 2L configurations. We examine a broad class of simple `metrics' that quantify the science output, related to compact binary coalescences, multi-messenger astronomy and stochastic backgrounds, and we then examine the impact of different detector designs on a more specific set of scientific objectives.
