Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Non-volatile memory cell having metal nano-particles for trapping charges and fabrication thereof

[[abstract]]A non-volatile memory cell is described. The non-volatile memory cell comprises a substrate, a charge-trapping layer, a gate and a source/drain. The charge-trapping layer comprises an insulating layer and metal nano-particles contained therein, wherein the metal nano-particles are formed with thermal dissociation of an oxide of the same metal. The gate is disposed on the charge-trapping layer, and the source/drain is located in the substrate beside the gate.[[fileno]]2020326060006[[department]]材料科學工程學

Thermosensitive Cationic Magnetic Liposomes for Thermoresponsive Delivery of CPT-11 and SLP2 shRNA in Glioblastoma Treatment

Thermosensitive cationic magnetic liposomes (TCMLs), prepared from dipalmitoylphosphatidylcholine (DPPC), cholesterol, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)]-2000, and didodecyldimethylammonium bromide (DDAB) were used in this study for the controlled release of drug/gene for cancer treatment. After co-entrapping citric-acid-coated magnetic nanoparticles (MNPs) and the chemotherapeutic drug irinotecan (CPT-11) in the core of TCML (TCML@CPT-11), SLP2 shRNA plasmids were complexed with DDAB in the lipid bilayer to prepare TCML@CPT-11/shRNA with a 135.6 ± 2.1 nm diameter. As DPPC has a melting temperature slightly above the physiological temperature, drug release from the liposomes can be triggered by an increase in solution temperature or by magneto-heating induced with an alternating magnetic field (AMF). The MNPs in the liposomes also endow the TCMLs with magnetically targeted drug delivery with guidance by a magnetic field. The successful preparation of drug-loaded liposomes was confirmed by various physical and chemical methods. Enhanced drug release, from 18% to 59%, at pH 7.4 was observed when raising the temperature from 37 to 43 °C, as well as during induction with an AMF. The in vitro cell culture experiments endorse the biocompatibility of TCMLs, whereas TCML@CPT-11 shows some enhancement of cytotoxicity toward U87 human glioblastoma cells when compared with free CPT-11. The U87 cells can be transfected with the SLP2 shRNA plasmids with very high efficiency (~100%), leading to silencing of the SLP2 gene and reducing the migration ability of U87 from 63% to 24% in a wound-healing assay. Finally, an in vivo study, using subcutaneously implanted U87 xenografts in nude mice, demonstrates that the intravenous injection of TCML@CPT11-shRNA, plus magnetic guidance and AMF treatment, can provide a safe and promising therapeutic modality for glioblastoma treatment

Surface-Enhanced Raman Scattering Microchip Fabricated by Femtosecond Laser

We report a surface-enhanced Raman scattering (SERS) microchip that is capable of measuring SERS signals of liquid samples with high sensitivity. The microdevice is an integration of a silicon-based SERS substrate, a multimode optical fiber (MMF), and a microchannel embedded in the photosensitive glass fabricated by the femtosecond laser followed by thermal treatment, wet etching, and annealing. The performance of the SERS microchip is evaluated by measuring rhodamine 6G using a 632.8nm He-Ne laser at 4.3mW excitation power, which reveals that the detection limit is lower than 10 -10M at a 1s short accumulation time

Laser-Treated Substrate with Nanoparticles for Surface-Enhanced Raman Scattering

A rapid and simple approach to fabricate a large area of nanostructured substrate for surface-enhanced Raman scattering (SERS) is reported. Gold nanoparticles ranging from 10to40-‰nm in diameter uniformly distributed on a silicon substrate were obtained by annealing the gold film precoated on the silicon substrate with UV nanosenond (ns) laser pulses. The gold nanoparticles were formed by surface tension of the melted gold layer heated by ns laser pulses. The enhancement factor of the SERS substrate for Rhodamine 6G at 632.8-‰nm excitation was measured to be higher than 105 . The proposed technique provides the opportunity to equip a functional microchip with SERS capability of high sensitivity and chemical stability

Driving Device Comparison for Phase-Change Memory

A study is conducted to investigate the relative advantages of different driving devices for phase-change memory cells using 3-D numerical device simulation. Among various possible choices, p-n diodes and vertical gate-all-around (GAA) metal-oxide-semiconductor field-effect transistors (MOSFETs) are studied in detail as they represent distinct classes of driving devices. Different performance parameters including cell size, current drive, disturb immunity, power dissipation, and scalability are carefully compared. While p-n diodes show superiority in technology nodes with large device dimensions, the scaling process has improved the performance of GAA MOSFETs significantly to outperform that of p-n diodes in extremely scaled technologies