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Atomic Layers of Ruthenium Oxide Coupled with Mo2TiC2Tx MXene for Exceptionally High Catalytic Activity Toward Water Oxidation
No full textProgress in acidic water splitting has remained limited because of low oxygen evolution reaction (OER) activities, sluggish reaction kinetics, and severe catalyst degradation. Thus, a highly active and durable OER catalyst is required for the commercialization of acidic water electrolyzers. Here, we report t-phase ruthenium oxide atomic layers implanted on Mo2TiC2Tx MXene (RAL-M) as a model electrocatalyst for the OER in acidic media, which exhibits a remarkable mass activity (6.2 A mg???1), excellent turnover frequency (TOF; 2.4 s???1), and negligible loss of durability after 22 h in a two-electrode cell configuration. The mass activity and TOF of RAL-M are 150 times (RuO2-Premetek Co.) and 540 times (RuO2-Sigma-Aldrich) greater than the industrially adopted electrocatalysts at pH 0.48. Computational calculations show that the ruthenium active sites of RAL-M have a strong affinity to oxygen species (e.g., OH*, O*, and OOH*), which efficiently adapts water dissociation and favors both the adsorbate evolution and lattice oxygen mechanistic pathways to accelerate the OER
A Phosphorofluoridate-Based Multifunctional Electrolyte Additive Enables Long Cycling of High-Energy Lithium-Ion Batteries
No full textNi-rich layered oxides are regarded as key componentsfor realizingpost Li-ion batteries (LIBs). However, high-valence Ni, which actsas an oxidant in deeply delithiated states, aggravates the oxidationof the electrolyte at the cathode, causing cell impedance to increase.Additionally, the leaching of transition metal (TM) ions from Ni-richcathodes by acidic compounds such as Bronsted-acidic HF producedthrough LiPF6 hydrolysis aggravates the structural instabilityof the cathode and renders the electrode-electrolyte interfaceunstable. Herein, we present a multifunctional electrolyte additive,bis(trimethylsilyl) phosphorofluoridate (BTSPFA), to attain enhancedinterfacial stability of graphite anodes and Ni-rich cathodes in Li-ioncells. BTSPFA eliminates the corrosive HF molecules by cleaving silylether bonds and enables the formation of a polar P-O- and P-F-enrichedcathode electrolyte interface (CEI) on the Ni-rich cathode. It alsopromotes the creation of a solid electrolyte interphase composed ofinorganic-rich species, which suppresses the reduction of the electrolyteduring battery operation. The synergistic effect of the HF scavengingability of BTSPFA and the stable BTSPFA-promoted CEI effectively suppressesthe TM leaching from the Ni-rich cathode while also preventing unwantedTM deposition on the anode. LiNi0.8Co0.1Mn0.1O2/graphite full cells with 1 wt % BTSPFA exhibitedan enhanced discharge capacity retention of 79.8% after 500 cyclesat 1C and 45 & DEG;C. These unique features of BTSPFA are useful forresolving the interfacial deterioration issue of high-capacity Ni-richcathodes paired with graphite anodes
Genomic characteristics of triple negative apocrine carcinoma: a comparison to triple negative breast cancer
No full textApocrine carcinoma is a rare breast cancer subtype. As such, the genomic characteristics of apocrine carcinoma with triple negative immunohistochemical results (TNAC), which has been treated as triple negative breast cancer (TNBC), have not been revealed. In this study, we evaluated the genomic characteristics of TNAC compared to TNBC with low Ki-67 (LK-TNBC). In the genetic analysis of 73 TNACs and 32 LK-TNBCs, the most frequently mutated driver gene in TNAC was TP53 (16/56, 28.6%), followed by PIK3CA (9/56, 16.1%), ZNF717 (8/56, 14.3%), and PIK3R1 (6/56, 10.71%). Mutational signature analysis showed enrichment of defective DNA mismatch repair (MMR)-related signatures (SBS6 and SBS21) and the SBS5 signature in TNAC, whereas an APOBEC activity-associated mutational signature (SBS13) was more prominent in LK-TNBC (Student's t test, p < 0.05). In intrinsic subtyping, 38.4% of TNACs were classified as luminal A, 27.4% as luminal B, 26.0% as HER2-enriched (HER2-E), 2.7% as basal, and 5.5% as normal-like. The basal subtype was the most dominant subtype (43.8%) in LK-TNBC (p < 0.001), followed by luminal B (21.9%), HER2-E (21.9%), and luminal A (12.5%). In the survival analysis, TNAC had a five-year disease-free survival (DFS) rate of 92.2% compared to 59.1% for LK-TNBC (P = 0.001) and a five-year overall survival (OS) rate of 95.3% compared to 74.6% for LK-TNBC (P = 0.0099). TNAC has different genetic characteristics and better survival outcomes than LK-TNBC. In particular, normal-like and luminal A subtypes in TNAC have much better DFS and OS than other intrinsic subtypes. Our findings are expected to impact medical practice for patients diagnosed with TNAC. Breast cancer: Genomic characteristics of rare subtype examinedA comparative study reveals the distinctive genomic and clinical characteristics of a rare form of breast cancer, with implications for treatment. Apocrine carcinoma accounts for 1-4 percent of breast cancer cases. The molecular characteristics of a subtype known as triple negative apocrine carcinoma (TNAC) remain unclear. Ji-Yeon Kim at Sungkyunkwan University School of Medicine, Seoul, South Korea, and co-workers conducted genomic analysis on tumor samples taken from 73 TNAC patients. They compared the results to samples from 32 triple negative breast cancer (TNBC) in which the low expression of Ki-67, a marker protein for cancer proliferation, was similar to the TNAC patients. TNAC patients had different genetic mutations and a better survival outcome than TNBC patients with low Ki-67. Therefore, early-stage TNAC may not require chemotherapy after surgery. Further research into TNAC genomic characteristics is warranted
Effect of black level and color gamut on display brightness
No full textThis study investigates the effect of the black level and color gamut on the overall display brightness using a psychophysical experiment. Two stimuli with different color gamut were matched until the overall brightness appeared the same by controlling the peak display luminance. Three experimental sessions were conducted with varying black levels and color gamut. The results indicate that the effect of the color gamut on perceived brightness was significant, unlike that of the black level. The matched luminance increased by 6% to 8% as the color gamut widened from sRGB to DCI-P3. The equivalent luminance prediction models were tested using the average stimuli luminance, exhibiting poor performances
Population of Merging Compact Binaries Inferred Using Gravitational Waves through GWTC-3
No full textWe report on the population properties of compact binary mergers inferred from gravitational-wave observations of these systems during the first three LIGO-Virgo observing runs. The Gravitational-Wave Transient Catalog 3 (GWTC-3) contains signals consistent with three classes of binary mergers: binary black hole, binary neutron star, and neutron star-black hole mergers. We infer the binary neutron star merger rate to be between 10 and 1700 Gpc-3 yr-1 and the neutron star-black hole merger rate to be between 7.8 and 140 Gpc-3 yr-1, assuming a constant rate density in the comoving frame and taking the union of 90% credible intervals for methods used in this work. We infer the binary black hole merger rate, allowing for evolution with redshift, to be between 17.9 and 44 Gpc-3 yr-1 at a fiducial redshift (z = 0.2). The rate of binary black hole mergers is observed to increase with redshift at a rate proportional to o1 + z thorn kappa with kappa = 2.9+1.7 -1.8 for z less than or similar to 1. Using both binary neutron star and neutron star-black hole binaries, we obtain a broad, relatively flat neutron star mass distribution extending from 1.2+0.1-0.2to 2.0+0.3 -0.3 M circle dot. We confidently determine that the merger rate as a function of mass sharply declines after the expected maximum neutron star mass, but cannot yet confirm or rule out the existence of a lower mass gap between neutron stars and black holes. We also find the binary black hole mass distribution has localized over-and underdensities relative to a power-law distribution, with peaks emerging at chirp masses of 8.3+0.3-0.5 and 27.9+1.9 -1.8 M circle dot. While we continue to find that the mass distribution of a binary's more massive component strongly decreases as a function of primary mass, we observe no evidence of a strongly suppressed merger rate above approximately 60M circle dot, which would indicate the presence of a upper mass gap. Observed black hole spins are small, with half of spin magnitudes below chi i approximate to 0.25. While the majority of spins are preferentially aligned with the orbital angular momentum, we infer evidence of antialigned spins among the binary population. We observe an increase in spin magnitude for systems with more unequal-mass ratio. We also observe evidence of misalignment of spins relative to the orbital angular momentum
Tunable voltage polarity-dependent resistive switching characteristics by interface energy barrier modulation in ceria-based bilayer memristors for neuromorphic computing
No full textSynaptic characteristics with tunable dependence on the voltage polarity are demonstrated in ceria (CeO2) and Gd-doped ceria (GDC) bilayer memristors with respect to their stacking orders. Both Pt/GDC/CeO2/Pt and Pt/ CeO2/GDC/Pt memristors with different oxide stacking orders exhibit analog, linear, and symmetric synaptic weights for potentiation and depression, paired-pulse facilitation, and short- and long-term plasticity (STP and LTP, respectively). Potentiation and depression behaviors are highly linear and symmetric thanks to the stacking of more oxygen-deficient GDC layer with CeO2, which facilitates the redistribution of oxygen vacancies for analog resistance change. These memristors have opposite dependence of synaptic weight updates on the polarity of potentiation and depression voltages for the stacking order of CeO2 and GDC, which are consistently interpreted by voltage-driven energy barrier modulation at the interface between CeO2 and GDC or with Pt electrodes via oxygen vacancy redistribution. Recognition simulation with modified handwritten digits patterns using a two-layer perceptron neural network exhibits accuracy of approximately 88% with achieved dynamic range, linearity, symmetry, and precision states. These synaptic characteristics are also demonstrated in a 32 x 32 crossbar array of GDC-top memristors. This verifies the potential of bilayer memristors for application in artificial synapse networks in neuromorphic computing systems
Effects of the nozzle-to-nozzle distance on the performance of the water condensation growth-based virus aerosol concentrator
No full textEfficient collection of airborne viruses is crucial for monitoring and preventing the spread of respiratory diseases. The laminar flow water condensation-based growth tube collector (GTC) is a microbial sampler extensively used to collect virus aerosol particles owing to its high recovery of viable viruses. The GTC involves multiple nozzles and eight tubes for sampling flow rates of 6???8 L per minute (LPM). To allow the GTC to operate at a higher flow rate, optimizing GTC performance through investigation of the effects of nozzle-to-nozzle distance is essential. Herein, we examined these effects on the collection efficiency and viability of airborne MS2 viruses collected by the growth-based virus aerosol concentrator (GVC), which is a lab-made single-tubed GTC, at flow rates of up to 6 LPM per tube. The flow interactions between adjacent jets were analyzed by observing the particle deposition patterns. The collection efficiencies of MS2 virus aerosol particles and the enrichment ratio of the GVC increased with increasing nozzle-to-nozzle distance. The infectious virus concentration relative to that in the virus suspension (RIVC) ranged from 0.0093 to 0.095 for 5 min of sampling. At flow rates of 1 and 6 LPM, the RIVC decreased as the nozzle-to-nozzle distance decreased, which may be ascribed to the higher shear stress at shorter nozzle-to-nozzle distances applied to the viruses collected through the cross-flows driven by adjacent jets. These measured RIVC values are much larger than those collected by the BioSampler. These findings can provide important insights into optimizing multiple nozzles in high-flow-rate GTCs
Semi-parametric contextual bandits with graph-Laplacian regularization
No full textNon-stationarity is ubiquitous in human behavior and addressing it in the contextual bandits is challenging. Several works have addressed the problem by investigating semi-parametric contextual bandits and warned that ignoring non-stationarity could harm performances. Another prevalent human behavior is social interaction which has become available in a form of a social network or graph structure. As a result, graph-based contextual bandits have received much attention. In this paper, we propose SemiGraphTS, a novel contextual Thompson-sampling algorithm for a graph-based semi-parametric reward model. Our algorithm is the first to be proposed in this setting. We derive an upper bound of the cumulative regret that can be expressed as a multiple of a factor depending on the graph structure and the order for the semi-parametric model without a graph. We evaluate the proposed and existing algorithms via simulation and real data example
Experimental study on 3D printed heat pipes with hybrid screen-groove combined capillary wick structure
No full textThe integration of heat pipes as a passive thermal management system for nuclear reactors has been proposed as it provides the advantages of compact design, reliability, efficient heat transfer performance, and enhanced safety. Applying the heat pipe to a nuclear reactor without collision between systems and achieving efficient long-distance heat transfer requires the manufacturing of heat pipes with a high degree of freedom. Using threedimensional (3D)-printing technology can be a solution for fabricating complex or bent capillary wick heat pipes into an integrated geometry. The study involves the production of a heat pipe using metal 3D-printing technology and an experimental study conducted for thermal performance evaluation. The heat pipe includes a combination of a screen-groove wick in the evaporator section, a groove wick in the adiabatic and condenser sections, and a bent wick structure in the middle. By using 3D printing technology, it is possible to create a heat pipe that has a complex wick design, a consistent porous structure and remains undistorted during the manufacturing process. The surface roughness of the 3D-printed heat pipe was 17 to 1700 times higher than the commercial stainlesssteel pipe, which has the benefit for enhance capillary performance. The experimental results showed that the 3D-printed heat pipe can achieve high effective thermal conductivity up to 25.7 kW/m-K and showed 24.2% lower thermal resistance compared to the conventionally manufactured heat pipe. Furthermore, it can be successfully operated at various inclination angles