Universal features in the photoemission spectroscopy of high-temperature superconductors.

The energy gap for electronic excitations is one of the most important characteristics of the superconducting state, as it directly reflects the pairing of electrons. In the copper-oxide high-temperature superconductors (HTSCs), a strongly anisotropic energy gap, which vanishes along high-symmetry directions, is a clear manifestation of the d-wave symmetry of the pairing. There is, however, a dramatic change in the form of the gap anisotropy with reduced carrier concentration (underdoping). Although the vanishing of the gap along the diagonal to the square Cu-O bond directions is robust, the doping dependence of the large gap along the Cu-O directions suggests that its origin might be different from pairing. It is thus tempting to associate the large gap with a second-order parameter distinct from superconductivity. We use angle-resolved photoemission spectroscopy to show that the two-gap behavior and the destruction of well-defined electronic excitations are not universal features of HTSCs, and depend sensitively on how the underdoped materials are prepared. Depending on cation substitution, underdoped samples either show two-gap behavior or not. In contrast, many other characteristics of HTSCs, such as the dome-like dependence of on doping, long-lived excitations along the diagonals to the Cu-O bonds, and an energy gap at the Brillouin zone boundary that decreases monotonically with doping while persisting above (the pseudogap), are present in all samples, irrespective of whether they exhibit two-gap behavior or not. Our results imply that universal aspects of high- superconductivity are relatively insensitive to differences in the electronic states along the Cu-O bond directions.

Electronic phase diagram of high-temperature copper oxide superconductors.

In order to understand the origin of high-temperature superconductivity in copper oxides, we must understand the normal state from which it emerges. Here, we examine the evolution of the normal state electronic excitations with temperature and carrier concentration in Bi(2)Sr(2)CaCu(2)O(8+δ) using angle-resolved photoemission. In contrast to conventional superconductors, where there is a single temperature scale T(c) separating the normal from the superconducting state, the high-temperature superconductors exhibit two additional temperature scales. One is the pseudogap scale T(∗), below which electronic excitations exhibit an energy gap. The second is the coherence scale T(coh), below which sharp spectral features appear due to increased lifetime of the excitations. We find that T(∗) and T(coh) are strongly doping dependent and cross each other near optimal doping. Thus the highest superconducting T(c) emerges from an unusual normal state that is characterized by coherent excitations with an energy gap.

Big Data-Artificial Intelligence Fusion Technology in Education in the Context of the New Crown Epidemic.

This article presents an in-depth study and analysis of the application of big data-artificial intelligence fusion technology to the field of education in the context of the New Crown epidemic. Since the outbreak of the New Crown epidemic, there is a need to understand the channels for solving the demands of productive life during the epidemic, and the main way to solve these problems is to apply the Internet, big data, and artificial intelligence. Therefore, exploring the application of big data-artificial intelligence fusion technology in education in the context of the New Crest pneumonia epidemic is a top priority for reform and development nowadays. This study uses the paradigm narrow shift analysis framework to verify whether Computer Aided Instructional design, multimedia instructional design, and informational instructional design produce migration. For the intelligent stage of instructional design, the inevitability of the change in basic assumptions of instructional design in the context of artificial intelligence (AI) is first explained in terms of the opportunities brought by AI to education and teaching, the problems of the original information-based instructional design itself, and the many challenges it faces. On this basis, we also use the change in basic assumptions analysis framework to explain the content of intelligent instructional design by using the four elements of beliefs, values, symbols, and paradigms promised by the members of the community, verify that it has shifted, and build a change in the basic assumptions model from multimedia instructional design to information-based instructional design to intelligent instructional design. The article gives three countermeasures to solve the problem, that is, raising awareness, improving the plan, and strengthening the drill. To ensure the smooth implementation of the emergency management of national covid control program (NCCP), higher education institutions should further strengthen the construction efforts of specialized psychological counseling teams, build an early warning mechanism for psychological problems of the NCCP epidemic in higher education institutions, and a multilevel supervision system.

Denoising and feature extraction in photoemission spectra with variational auto-encoder neural networks.

In recent years, distinct machine learning (ML) models have been separately used for feature extraction and noise reduction from energy-momentum dispersion intensity maps obtained from raw angle-resolved photoemission spectroscopy (ARPES) data. In this work, we employ a shallow variational auto-encoder neural network to demonstrate the prospect of using ML for both denoising of as well as feature extraction from ARPES dispersion maps.

Expression of heat shock protein 70 and Annexin A1 in serum of patients with acutely severe traumatic brain injury.

Trends of early expression levels of heat shock protein 70 (Hsp70) and Annexin A1 (ANXA1) in serum of patients with acutely severe traumatic brain injury and the effects on clinical prognosis were investigated. Eighty-four patients with severe traumatic brain injury admitted to Binzhou Center Hospital from June 2014 to July 2017 were selected as the experimental group. Glasgow coma scale and acute physiology and chronic health evaluation II (APACHE II) score were obtained after admission. A further 75 healthy subjects were selected as the control group. Serum expression of Hsp70 and ANXA1 in the two groups was detected by enzyme-linked immunosorbent assay on the 1st, 2nd, 3rd and 4th day after admission. The receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of Hsp70 and ANXA1 for the death of patients with acutely severe traumatic brain injury. Compared with the control group, expression of Hsp70 in the experimental group was significantly increased on the 1st, 2nd, 3rd and 4th day after admission (P<0.05), while expression of ANXA1 was significantly decreased (P<0.05). Expression levels of serum Hsp70 in the experimental group reached the peak on the 3rd day after admission, and the difference was statistically significant compared with the 1st, 2nd and 4th day (P<0.05). Expression of ANXA1 was the lowest on the 3rd day, and the difference was statistically significant compared with the 1st, 2nd and 4th day (P<0.05). The ROC curve analysis showed that the area under the curve of serum Hsp70 and ANXA1 was, respectively, 0.721 (95% CI: 0.611-0.829) and 0.684 (95% CI: 0.569-0.799). In conclusion, Hsp70 and ANXA1 may be involved in the occurrence and progression of acutely severe traumatic brain injury. The detection of serum Hsp70 and ANXA1 has certain diagnostic value for the death of patients with acutely severe traumatic brain injury.

Immunology, Treatment and Public Health Aspects of Subarachnoid Hemorrhage.

BACKGROUND: We aimed to explore the treatment and safety of subarachnoid hemorrhage. METHODS: A retrospective analysis was applied on 137 patients with subarachnoid hemorrhage treated in Binzhou Central Hospital, Bingzhou, China from March 2015 to October 2018. Seventy cases with interventional embolization of intracranial aneurysms were divided as the observation group, and 67 cases with craniotomy for aneurysm clipping were divided as the control group. The changes of immune globulins before and after surgery, CD4+, CD8+, NIHSS scores, BI scores, the total effective rate of subarachnoid hemorrhage, the total length of postoperative hospital stay and conditions of postoperative complications as well as 30-day survival were compared between the two groups. RESULTS: The levels of Ig G, Ig M, Ig A, and CD4+ after surgery in the observation group were significantly lower than those before surgery (P<0.05), but significantly higher than those in the control group (P<0.05); the total time of postoperative hospitalization in the observation group was shorter than that in the control group (P<0.05). The incidence of intracranial infection and cerebral vasospasm in the observation group was significantly lower than that in the control group (P<0.05). The NIHSS score of the observation group was significantly lower than that of the control group (P<0.05), and the BI score was significantly higher than that of the control group (P<0.05). CONCLUSION: Patients with subarachnoid hemorrhage undergoing interventional embolization of aneurysms can reduce the impact on immune function, decrease the adverse reactions caused by treatments, shorten the length of hospital stay and fully improve the efficacy.