The spectral picture of Bergman Toeplitz operators with harmonic polynomial symbols

In this paper, it is shown that some new phenomenon related to the spectra of Toeplitz operators with bounded harmonic symbols on the Bergman space. On the one hand, we prove that the spectrum of the Toeplitz operator with symbol ${\bar{z}+p}$ is always connected for every polynomial $p$ with degree less than $3$. On the other hand, we show that for each integer $k$ greater than $2$, there exists a polynomial $p$ of degree $k$ such that the spectrum of the Toeplitz operator with symbol ${\bar{z}+p}$ has at least one isolated point but has at most finitely many isolated points. Then these results are applied to obtain a new class of non-hyponormal Toeplitz operators with bounded harmonic symbols on the Bergman space for which Weyl's theorem holds.Comment: 21 page

Essentially normal quotient weighted Bergman modules over the bidisk and distinguished varieties

We introduce a Grassmannian structure for a class of quotient Hilbert modules and attack the polydisc version of Arveson-Douglas conjecture associated to distinguished varieties. More interestingly, we obtain an operator-theoretic characterization of distinguished varieties in the bidisk in terms of essential normality of the quotient modules. As an application, we study the K-homology of the boundary of distinguished variety

Mineralization of organic matter in microbialites and implications for microbialite reservoirs in Member IV of the Leikoupo Formation, Sichuan Basin, China

Microbialites are important reservoirs for oil and gas. The mineralization of organic matter in microbialites during early diagenesis can produce acidic fluids that dissolve carbonate grains, and can also result in an alkaline pore water that precipitates cement. The mineralization of organic matter in microbialites and its effect on microbialite reservoirs have not yet been studied in detail. In this study, quantitative statistical analysis of the two-dimensional spatial occurrence of pores and microbial fabrics, in situ geochemical analysis of specific components (microbial, transitional zone, and fine spar fabrics), and qualitative evaluation of the implications for microbialite reservoirs were undertaken on microbialites from Member IV of the Leikoupo Formation, Sichuan Basin, China. The quantitative statistical analysis shows that pores are spatially associated with microbial fabrics, but porosity has a poor correlation with microbial fabric content. In situ geochemical data indicate that microbialites with different porosities experienced different processes of organic matter mineralization. The processes of organic matter mineralization such as oxidation and nitrate reduction can provide more dissolution micropores than the process related with sulfate reduction, whereas the process of organic matter mineralization related with Fe–Mn oxide reduction results in cementation. Micropores created by organic matter mineralization can act as fluid channels for later dissolution and are important in the development of microbialite reservoirs

Risk-Return Relationship in a Complex Adaptive System

For survival and development, autonomous agents in complex adaptive systems involving the human society must compete against or collaborate with others for sharing limited resources or wealth, by using different methods. One method is to invest, in order to obtain payoffs with risk. It is a common belief that investments with a positive risk-return relationship (namely, high risk high return and vice versa) are dominant over those with a negative risk-return relationship (i.e., high risk low return and vice versa) in the human society; the belief has a notable impact on daily investing activities of investors. Here we investigate the risk-return relationship in a model complex adaptive system, in order to study the effect of both market efficiency and closeness that exist in the human society and play an important role in helping to establish traditional finance/economics theories. We conduct a series of computer-aided human experiments, and also perform agent-based simulations and theoretical analysis to confirm the experimental observations and reveal the underlying mechanism. We report that investments with a negative risk-return relationship have dominance over those with a positive risk-return relationship instead in such a complex adaptive systems. We formulate the dynamical process for the system's evolution, which helps to discover the different role of identical and heterogeneous preferences. This work might be valuable not only to complexity science, but also to finance and economics, to management and social science, and to physics

The Benefits and Costs of Renminbi Internationalization

Despite the increasing recognition that the renminbi (RMB) may eventually become a key global currency, several important questions remain to be answered. This paper analyzes the benefits and costs of the RMB becoming an international currency. The benefits include reduced exchange risk, promotion of the development of the financial market, and expansion of firms in the People's Republic of China. The costs include general costs, which complicate monetary policy and exchange rate policy, and several transitional risks. We argue that the benefits of RMB internationalization should surpass its costs, particularly in the long run, and provide comprehensive policy choices for a sustainable process of RMB internationalization

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

Effect of Cu on the Formation of Reversed Austenite in Super Martensitic Stainless Steel

We investigated the effect of Cu on the formation of reversed austenite in super martensitic stainless steel by using X-ray diffraction (XRD), a transmission electron microscope (TEM) and an energy-dispersive spectrometer (EDS). Our results showed that the microstructure of the steels comprised tempered martensite and diffused reversed austenite after the steels were quenched at 1050 °C and tempered at 550–750 °C. The volume fraction of reversed austenite in the steel with 3 wt.% of Cu (3Cu) was more than that with 1.5 wt.% of Cu (1.5Cu). The transmission electron microscope results revealed that the reversed austenite in 1.5Cu steel mainly had the shape of a thin strip, while that in 3Cu steel had a block shape. The nucleation points and degree of Ni enrichment of reversed austenite in 3Cu steel were higher than those in 1.5Cu steel. The reversed austenite was more likely to grow in ε-Cu enriched regions. Therefore, Cu can promote reversed austenite nucleation and growth. The mechanical properties of 3 Cu steel are obviously better than those of 1.5Cu steel when tempered at 550–650 °C

Recent Advances in Metal-Organic Frameworks and Their Derived Materials for Electrocatalytic Water Splitting

Highly efficient electrocatalysts play important roles in electrochemical water splitting for hydrogen production, including the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Metal-organic frameworks (MOFs) are porous crystalline materials, exhibiting strong potential as precursors for obtaining outstanding electrocatalysts. MOF-based electrocatalysts, including MOFs and MOF-derived electrocatalysts, have become an increasingly important part of catalysts in the field of electrochemical water splitting, but their catalytic performance, especially their activity and stability, still have a lot of room for improvement. In this paper, the preparation strategy of MOF-based electrocatalysts and improvement methods of catalytic properties were reviewed, including morphology-controlled methods and composition-controlled methods. We also focused on the structure-property relationships, which determine the electrocatalytic activity for water splitting reactions. Finally, the challenges and development prospects were discussed for the MOF-based electrocatalysts, which might provide some insight for future applications in electrochemical water splitting

UAV-based emergency treatment plan for flood disasters at the Hongyanhe nuclear power plant

This paper explores the potential of the joint application of unmanned aerial vehicle(UAV)-based the belief-desire-intention (BDI) algorithm constructed for rescue by NetLogo and the flood model of the Hongyanhe Nuclear Power Plant based on the Global Surface Water (GSW) dataset. The study revealed the high potential of the GSW dataset provides useful data for detecting the occurrence of flood events about the Hongyanhe Nuclear Power Plant, the major features are as: the areas affected by the floods in the grid system for emergency treatment at the nuclear power station were: grid area718, 758, 759, 798, 799, and 839;the most affected grid areas were grid areas 758–759 and 798–799; these were the important areas, incorporating the storage area for wastewater, waste liquid and waste solids, the comprehensive office building, and No. 6 shelter. The study also reveals that the success rate of UAV rescue using a single drone was 59.8% (standard deviation 0.1657, standard error 0.0166, 95% Confidence Interval),and there was no significant difference in the results between the two groups(significance of the one-way analysis of variance P = 0.662 > 0.05); the success rate of UAV rescue using two drones was 58.8% (standard deviation 0.1572, standard error 0.0157, 95% Confidence Interval); the simulated time of completing the rescue task using a single drone was 5484.09 (standard deviation 2447.7519, standard error 244.7752, 95% Confidence Interval); and the simulated time of completing the rescue task using two drones was 4679.22 (standard deviation 3109.4676, standard error 310.9468, 95% Confidence Interval). Thus, the rescue efficiency was higher using two drones than using one drone (level of significance from the one-way analysis of variance P = 0.043 < 0.05)