The usual advice given to a first year student is that while the student is reading lectures notes or working with a textbook at home, he has to try to perform the derivations on his own, and even to try to first find...
详细信息
The usual advice given to a first year student is that while the student is reading lectures notes or working with a textbook at home, he has to try to perform the derivations on his own, and even to try to first find his own way to solve the problem example, and only after that to study these details in the source. It is thought, reasonably, that in this way, the study will be effective and the student will acquire good comprehension and obtain new tools which could then be actively used. However, this advice is only a part of more complete and self-consistent advice. This paper presents more complete advice which consists of three parts, of which the first is the advice already considered.
We investigate the impact of quantum well (QW) thickness on efficiency loss in c-plane InGaN/GaN LEDs using a small-signal electroluminescence (SSEL) technique. Multiple mechanisms related to efficiency loss are indep...
详细信息
The quality of Li–solid electrolyte interface is crucial for the performance of solid-state lithium metal batteries, particularly at low stack pressure, but its dynamics during cell operation remain poorly understood...
In this report, we apply a suite of ultrafast spectroscopic techniques and advanced calculations to reveal the interplay between electronic and lattice degrees of freedom in ferroelectric BiFeO3. Using transient sum f...
详细信息
In this report, we apply a suite of ultrafast spectroscopic techniques and advanced calculations to reveal the interplay between electronic and lattice degrees of freedom in ferroelectric BiFeO3. Using transient sum frequency generation spectroscopy, which is sensitive to electronic polarizations, we observe a transient electronic dipole reduction upon optical excitation which recovers at 0.5 and 10 ps timescale. The time-dependent density functional theory calculation reveals that both ligand-metal charge transfer and local excitation transition occurred upon photo excitation. To reveal the nature of electronic dipole restoration, we employ transient extreme ultraviolet (EUV) spectroscopy—an element-specific ultrafast technique that follows charge dynamics of Bi, Fe, and O altogether. The transient EUV dynamics observed both ultrafast free charge carrier relaxation to excitons, as well as polaron formation. However, a timescale comparison suggests that only the polaron formation is responsible for the 0.5 ps electronic dipole restoration, whereas the faster electronic relaxation does not contribute to the ferroelectric property changes. Multireference configuration interaction calculation further corroborates this result by showing both Fe and Bi atoms shift from the ground state equilibrium—leading to the polaron formation. Our result disentangles the multidegrees of freedom in ultrafast ferroelectric modulation and identifies the pivotal motion—a local polaron formation—for the fast ferroelectric recovery. It provides crucial insights on the specific lattice distortion that could modulate properties or phase transitions of condensed matter materials.
The analysis of a system model with special structured properties is presented in this paper. In particular, the analytical and simulation techniques for computing the system response in the context of a descriptor-li...
The analysis of a system model with special structured properties is presented in this paper. In particular, the analytical and simulation techniques for computing the system response in the context of a descriptor-like model is developed. In addition, the stability theorems for this model are also developed. This includes the formulation of both the classical and modern stability methods. The latter method leads to a generalized form of the Liapunov equation. The computational saving associated with using the methods developed here is also discussed.
Investigations on the junctions made between Pb and polycrystalline Bi2Sr2CaCu2O8+x (BSCCO) are reported. The BSCCO surfaces were treated with number of methods including mechanically scraping, plasma sputtering, plas...
详细信息
Investigations on the junctions made between Pb and polycrystalline Bi2Sr2CaCu2O8+x (BSCCO) are reported. The BSCCO surfaces were treated with number of methods including mechanically scraping, plasma sputtering, plasma oxidation, and Br etch before junctions were fabricated. The current-voltage characteristics and dynamic resistance (dV/dI) vs voltage have been measured at both 77K and 4.2K. We observed, among other features, a Pb gap structure similar to that seen in Pb/YBa2Cu3O7-delta junctions, a magnetic dependent supercurrent, an asymmetric I-V curve, and narrow resistance peaks. Properties of junctions prepared in different manners are compared. Both XPS and electrical studies indicated that Br etch is not suitable for the BiSrCaCuO system in spite of its successful application in YBa2Cu3O7-delta.
The concept of an optical fuzzy flip-flop, as an essential and basic component for the effective processing of fuzzy information, is introduced. A design based on the area-encoding technique and a multiple-imaging sys...
详细信息
The concept of an optical fuzzy flip-flop, as an essential and basic component for the effective processing of fuzzy information, is introduced. A design based on the area-encoding technique and a multiple-imaging system is proposed to implement two types of fuzzy J-K flip-flops. (C) John Wiley & Sons, Inc.
This research introduces a deep learning framework that combines convolutional neural networks with autoencoders to improve the diagnostic accuracy of knee osteoarthritis. The study utilized a publicly available datas...
详细信息
Deep learning (DL) and machine learning (ML) models have shown promise in drug response prediction (DRP), yet their ability to generalize across datasets remains an open question, raising concerns about their real-wor...
详细信息
暂无评论