Total embedding distributions of Ringel ladders

The total embedding distributions of a graph is consisted of the orientable embeddings and non- orientable embeddings and have been know for few classes of graphs. The genus distribution of Ringel ladders is determined in [Discrete Mathematics 216 (2000) 235-252] by E.H. Tesar. In this paper, the explicit formula for non-orientable embeddings of Ringel ladders is obtained

Does Co-Location Accelerate Knowledge Outflows from FDI? The Role of MMC Subsidiaries' Technology Sourcing Strategies

Despite the strategic importance of the knowledge outflows from FDI for local firms’ competitiveness, no study has focused on the speed at which this phenomenon takes place. However, this issue is crucial since the speed at which firms absorb external knowledge influences the time they need to carry out subsequent innovations, their ability to adapt to external changes and enter new markets, thus ultimately affecting their chances to achieve a competitive advantage. This paper tries to fill this gap, by investigating the temporal patterns of knowledge outflows between foreign subsidiaries and firms located in host-regions. Combining International Business literature with insights on Innovation Strategy, we provide evidence on the timing of this phenomenon, and discuss the role played by multinational firms’ technology sourcing strategies

Arrayed van der Waals Vertical Heterostructures based on 2D GaSe Grown by Molecular Beam Epitaxy

Vertically stacking two dimensional (2D) materials can enable the design of novel electronic and optoelectronic devices and realize complex functionality. However, the fabrication of such artificial heterostructures in wafer scale with an atomically-sharp interface poses an unprecedented challenge. Here, we demonstrate a convenient and controllable approach for the production of wafer-scale 2D GaSe thin films by molecular beam epitaxy. In-situ reflection high-energy electron diffraction oscillations and Raman spectroscopy reveal a layer-by-layer van der Waals epitaxial growth mode. Highly-efficient photodetector arrays were fabricated based on few-layer GaSe on Si. These photodiodes show steady rectifying characteristics and a relatively high external quantum efficiency of 23.6%. The resultant photoresponse is super-fast and robust with a response time of 60 us. Importantly, the device shows no sign of degradation after 1 million cycles of operation. Our study establishes a new approach to produce controllable, robust and large-area 2D heterostructures and presents a crucial step for further practical applications

Fast radio burst energy function in the presence of DMhost\rm DM_{host} variation

Fast radio bursts (FRBs) have been found in great numbers but the physical mechanism of these sources is still a mystery. The redshift evolutions of the FRB energy distribution function and the volumetric rate shed light on revealing the origin of the FRBs. However, such estimations rely on the dispersion measurement (DM)-redshift ($z$) relationship. A few of FRBs detected recently show large excess DM beyond the expectation from the cosmological and Milky Way contributions, which indicates large spread of DM from their host galaxies. In this work, we adopt the lognormal distributed $\rm DM_{host}$ model and estimate the energy function using the non-repeating FRBs selected from the Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB Catalog 1. By comparing the lognormal distributed $\rm DM_{host}$ model to the constant $\rm DM_{host}$ model, the FRB energy function results are consistent within the measurement uncertainty. We also estimate the volumetric rate of the non-repeating FRBs in three different redshift bins. The volumetric rate shows that the trend is consistent with the stellar-mass density redshift evolution. Since the lognormal distributed $\rm DM_{host}$ model increases the measurement errors, the inference of FRBs tracking the stellar-mass density is nonetheless undermined.Comment: 8 pages, 5 figure

First statistical measurement of the Hubble constant using unlocalized fast radio bursts

Fast radio bursts (FRBs) can be used to measure the Hubble constant by employing the Macquart relation. However, at present, only a small number of FRB events are localized to their host galaxies with known redshifts. In this paper, we develop a Bayesian method to statistically measure the Hubble constant using unlocalized FRBs and galaxy catalog data, which makes it possible to constrain cosmological parameters by using a large number of FRB data without known redshift information. Using the six FRB events observed by ASKAP combined with the big bang nucleosynthesis result, we obtain $H_0=71.7^{+8.8}_{-7.4}$ km s$^{-1}$ Mpc$^{-1}$ in the simulation-based case and $H_0=71.5^{+10.0}_{-8.1}$ km s$^{-1}$ Mpc$^{-1}$ in the observation-based case ($68\%$ highest-density interval), assuming different host galaxy population parameters. We also estimate that in the next few years, using thousands of FRBs could achieve a $3\%$ precision on the random error of the Hubble constant.Comment: 9 pages, 3 figure

A robust system model for the photovoltaic in industrial parks considering photovoltaic uncertainties and low-carbon demand response

Against the backdrop of carbon peaking and carbon neutrality initiatives, industrial parks have the potential to mitigate external electricity procurement and reduce carbon emissions by incorporating photovoltaic and energy storage systems. However, the inherent unpredictability in photovoltaic power generation poses notable challenges to the optimal planning of industrial parks. In light of this, the present study proposes a robust planning model for the distribution of photovoltaic and energy storage systems within industrial estates, taking into account uncertainties in photovoltaic output and low-carbon demand response. The primary objective of the model is to minimize the yearly comprehensive cost of the industrial park. It is grounded in the carbon emission flow theory, utilizing dynamic carbon emission factors calculated throughout the year as the pricing basis for real-time electricity rates informed by demand response. Subsequently, historical photovoltaic output data are employed to formulate typical output scenarios and their probability distributions through scenario clustering. These norms and constraints serve to bind the associated uncertainty probabilities. Consequently, a two-stage distribution robust model for the photovoltaic and energy storage system is established, employing a data-driven methodology. The efficacy of the proposed model is substantiated through a case simulation of an industrial park utilizing the CPLEX commercial solver. This approach not only underscores the importance of addressing uncertainties in photovoltaic power generation for industrial park planning but also showcases a practical application of the developed model