Andreev reflection at the interface with an oxide in the quantum Hall regime

Quantum Hall/superconductor junctions have been an attractive topic as the two macroscopically quantum states join at the interface. Despite longstanding efforts, however, experimental understanding of this system has not been settled yet. One of the reasons is that most semiconductors hosting high-mobility two-dimensional electron systems (2DES) usually form Schottky barriers at the metal contacts, preventing efficient proximity between the quantum Hall edge states and Cooper pairs. Only recently have relatively transparent 2DES/superconductor junctions been investigated in graphene. In this study, we propose another material system for investigating 2DES/superconductor junctions, that is ZnO-based heterostrcuture. Due to the ionic nature of ZnO, a Schottky barrier is not effectively formed at the contact with a superconductor MoGe, as evidenced by the appearance of Andreev reflection at low temperatures. With applying magnetic field, while clear quantum Hall effect is observed for ZnO 2DES, conductance across the junction oscillates with the filling factor of the quantum Hall states. We find that Andreev reflection is suppressed in the well developed quantum Hall regimes, which we interpret as a result of equal probabilities of normal and Andreev reflections as a result of multiple Andreev reflection at the 2DES/superconductor interface.Comment: 18 pages, 8 figure

Narita Tohl's Contribution to the Development of Character Design <Articles>

Currently, we are surrounded by numerous manga, anime and television game characters. This paper explicates the influence of character design development on character properties by focusing on a character created by Narita Tohl (1929- 2002), Kaiju. In ancient times, the kaiju symbolized a creature that transcended all human knowledge because it was a combination of animal parts; the ancient people believed animals were formidable. However, the current combinations used to depict the kaiju do not represent the supernatural abilities of the creature because people today do not believe in the power of animals. Designers before Narita had defined kaiju as a living creature and created using those combinations because they believed a realistic kaiju should have a body comprising known animal parts. By contrast, Narita defined kaiju as an unknown animal, and therefore his kaiju design incorporated inanimate and abstract forms. Thus, Narita freed the kaiju design from the restriction of using known animal parts. By means of this liberation, the symbolic form of kaiju, prevalent during the ancient times, was restored. Thus, the character design development by Narita changed the property of the character

Andreev Reflection at the Interface with an Oxide in the Quantum Hall Regime

Quantum Hall/superconductor junctions have been an attractive topic as the two macroscopically quantum states join at the interface. Despite longstanding efforts, however, experimental understanding of this system has not been settled yet. One of the reasons is that most semiconductors hosting high-mobility two-dimensional electron systems (2DES) usually form Schottky barriers at the metal contacts, preventing efficient proximity between the quantum Hall edge states and Cooper pairs. Only recently have relatively transparent 2DES/superconductor junctions been investigated in graphene. In this study, we propose another material system for investigating 2DES/superconductor junctions, that is ZnO-based heterostructure. Due to the ionic nature of ZnO, a Schottky barrier is not effectively formed at the contact with a superconductor MoGe, as evidenced by the appearance of Andreev reflection at low temperatures. With applying magnetic field, while clear quantum Hall effect is observed for ZnO 2DES, conductance across the junction oscillates with the filling factor of the quantum Hall states. We find that Andreev reflection is suppressed in the well developed quantum Hall regimes, which we interpret as a result of equal probabilities of normal and Andreev reflections as a result of multiple Andreev reflection at the 2DES/superconductor interface

Empirical Investigation of Neural Symbolic Reasoning Strategies

Neural reasoning accuracy improves when generating intermediate reasoning steps. However, the source of this improvement is yet unclear. Here, we investigate and factorize the benefit of generating intermediate steps for symbolic reasoning. Specifically, we decompose the reasoning strategy w.r.t. step granularity and chaining strategy. With a purely symbolic numerical reasoning dataset (e.g., A=1, B=3, C=A+3, C?), we found that the choice of reasoning strategies significantly affects the performance, with the gap becoming even larger as the extrapolation length becomes longer. Surprisingly, we also found that certain configurations lead to nearly perfect performance, even in the case of length extrapolation. Our results indicate the importance of further exploring effective strategies for neural reasoning models.Comment: This paper is accepted as the findings at EACL 2023, and the earlier version (non-archival) of this work got the Best Paper Award in the Student Research Workshop of AACL 202

Do Deep Neural Networks Capture Compositionality in Arithmetic Reasoning?

Compositionality is a pivotal property of symbolic reasoning. However, how well recent neural models capture compositionality remains underexplored in the symbolic reasoning tasks. This study empirically addresses this question by systematically examining recently published pre-trained seq2seq models with a carefully controlled dataset of multi-hop arithmetic symbolic reasoning. We introduce a skill tree on compositionality in arithmetic symbolic reasoning that defines the hierarchical levels of complexity along with three compositionality dimensions: systematicity, productivity, and substitutivity. Our experiments revealed that among the three types of composition, the models struggled most with systematicity, performing poorly even with relatively simple compositions. That difficulty was not resolved even after training the models with intermediate reasoning steps.Comment: accepted by EACL 202

Quinolizidines. XX. Racetnic and Chiral Syntheses of the Alangium Alkaloids 9-Demethylprotoemetinol and 10-Demethylprotoemetinol(Organic,Chemical)

The synthesis of (±)-9-demethylprotoemetinol [(±)-3d] was accomplished by LiAlH_4 reduction of the tricyclic ester (±)-5 and subsequent debenzylation of the resulting tricyclic-alcohol (±)-10. Acetylation of (±)-3d with acetic anhydride and pyridine gave the diacetate (±)-11. The same sequence of reactions starting with (-)-5 afforded (-)-9-demethylprotoemetinol [(-)-3d] and the diacetate (-)-11 through (-)-10. Parallel synthetic routes starting with the isomeric tricyclic esters (±)-9 and (-)-9 produced (±)- and (-)-10-demethylprotoemetinols [(±)-4d and (-)-4d] and the corresponding diacetates [(±)-13 and (-)-13] through (±)-12 and (-)-12, respectively. The correctness of the structure and absolute stereochemistry of an Alangiutn alkaloid inferred to be 10-demethylprotoemetinol was confirmed by a direct comparison of its diacetate with synthetic (-)-13

Hepatitis B virus core promoter mutations G1613A and C1653T are significantly associated with hepatocellular carcinoma in genotype C HBV-infected patients

<p>Abstract</p> <p>Background</p> <p>Hepatitis B virus (HBV) is a major cause of hepatocarcinogenesis.</p> <p>To identify mutations relevant to hepatocellular carcinoma (HCC) development, we compared the full genome sequences of HBV from the sera of patients with and without HCC.</p> <p>Methods</p> <p>We compared the full genome sequences of HBV isolates from 37 HCC patients (HCC group 1) and 38 patients without HCC (non-HCC group 1). We also investigated part of the core promoter region sequences from 40 HCC patients (HCC group 2) and 68 patients without HCC. Of the 68 patients who initially did not have HCC, 52 patients remained HCC-free during the follow-up period (non-HCC group 2), and 16 patients eventually developed HCC (pre-HCC group 2). Serum samples collected from patients were subjected to PCR, and the HBV DNA was directly sequenced.</p> <p>Results</p> <p>All patients had genotype C. A comparison of the nucleotide sequences of the HBV genome between HCC group 1 and non-HCC group 1 revealed that the prevalence of G1613A and C1653T mutations in the core promoter region was significantly higher in the HCC group. These mutations tended to occur simultaneously in HCC patients. Multivariate analysis with group 2 revealed that the presence of HCC was associated with aging and the double mutation. Future emergence of HCC was associated with aging and the presence of a single G1613A mutation.</p> <p>Conclusions</p> <p>G1613A and C1653T double mutations were frequently found in patients with HCC. A single G1613A mutation was associated with future emergence of HCC. These mutations may serve as useful markers in predicting HCC development.</p