Stack Options Research Articles

2D CrSBr Enables Magnetically Controllable Exciton‐Polaritons in an Open Cavity

Abstract 2D van der Waals (vdW) layered materials exhibit significant exciton binding energy and versatile stacking options, making them ideal for room‐temperature exciton‐polariton devices used in low‐threshold lasing, nonlinear optical switching, and quantum computing. However, most existing systems depend on external optical microcavities coupled with single monolayers, leading to limited controllability and increased costs. Here, external cavity‐free vdW magnet CrSBr crystals are presented that feature magnetically controllable self‐hybridized exciton‐polaritons that remain stable up to room temperature. The ultrastrong exciton‐photon coupling suppresses donor‐, phonon‐, and defect‐related emissions. Furthermore, the exciton‐polariton dispersion and emission spectra can be effectively controlled by adjusting the magnetic field, temperature, and CrSBr thickness. This vdW exciton‐polariton material platform, demonstrating remarkable magnetic responsiveness in open cavity configurations under ambient conditions, paves the way for the development of compact, fast, and low‐loss spin, quantum, and magneto‐photonic devices.

First-principles study on interfacial property in MgB2-based reactive hydride composites

The underlying physico-chemical interactions between transition metal-based boride particles that formed during the dehydrogenation process and MgB2 in 2LiBH4+MgH2 reactive hydride composite at the atomic scale are still unknown. In this work, the properties of the TiB2/MgB2 interface were investigated by first-principles calculations utilizing density functional theory (DFT). Taking the two terminations of both MgB2 and TiB2 as well as four different stacking sequences into account, energies of the TiB2 and MgB2 (0001) surfaces as well as the work of adhesion and the electronic structure of the interfaces were studied. The results show that the interface between the B-terminated MgB2 (0001) surface and the Ti-terminated TiB2 (0001) surface is the energetically most favorable among all four stacking options and possesses the largest work of adhesion. Our results further show that the TiB2 particles possess good nucleation potency for MgB2 particles from the thermodynamic perspective.

An End-To-End LwM2M-Based Communication Architecture for Multimodal NB-IoT/BLE Devices.

The wireless Internet of Things (IoT) landscape is quite diverse. For instance, Low-Power Wide-Area Network (LPWAN) technologies offer low data rate communication over long distance, whereas Wireless Personal Area Network (WPAN) technologies can reach higher data rates, but with a reduced range. For simple IoT applications, communication requirements can be fulfilled by a single technology. However, the requirements of more demanding IoT use cases can vary over time and with the type of data being exchanged. This is pushing the design towards multimodal approaches, where different wireless IoT technologies are combined and the most appropriate one is used as per the need. This paper considers the combination of Narrow Band IoT (NB-IoT) and Bluetooth Low Energy (BLE) as communication options for an IoT device that is running a Lightweight Machine to Machine/Constrained Application Protocol (LwM2M/CoAP) protocol stack. It analyses the challenges incurred by different protocol stack options, such as different transfer modes (IP versus non-IP), the use of Static Context Header Compression (SCHC) techniques, and Datagram Transport Layer Security (DTLS) security modes, and discusses the impact of handover between both communication technologies. A suitable end-to-end architecture for the targeted multimodal communication is presented. Using a prototype implementation of this architecture, an in-depth assessment of handover and its resulting latency is performed.

PROBE: A Placement, Routing, Back-End-of-Line Measurement Utility

In advanced technology nodes, correctly choosing among available back-end-of-line (BEOL) stack options is important to meet stringent design quality of results requirements. However, it is nontrivial to evaluate BEOL stack options since the routing outcomes highly depend on the input design (e.g., netlist, placement, etc.). In this paper, we propose a systematic framework to measure routing capacity of a BEOL stack as well as inherent capability of routers. Based on our experimental results, we observe consistent results across mesh-like placement and placements from various placers. Also, our proposed framework enables new insights into important questions regarding BEOL stack options. Using our framework, we further study the relation between the routing hotspot size and routing failure empirically. Lastly, we present an analytical study based on exponentiation of a Markov transition matrix about the impact of design size on routing failure.

First Ply Failure Loads of Composite Conoidal Shell Roofs with Varying Lamination

A number of industrial structures need large column free open spaces. Though the conoidal shells are doubly curved they are singly ruled too and are easy to fabricate and thus preferred in the industry. The laminated composites are well established today and there is a relevant question regarding the performance of different stacking options when the laminates are used to fabricate structural units. First ply failure analysis of conoidal shells are missing in the literature. This article uses the finite element method to evaluate relative performances of conoidal shells with varying laminations in terms of their first ply failure loads.

Current State of Technology of Fuel Cell Power Systems for Autonomous Underwater Vehicles

Autonomous Underwater Vehicles (AUVs) are vehicles that are primarily used to accomplish oceanographic research data collection and auxiliary offshore tasks. At the present time, they are usually powered by lithium-ion secondary batteries, which have insufficient specific energies. In order for this technology to achieve a mature state, increased endurance is required. Fuel cell power systems have been identified as an effective means to achieve this endurance but no implementation in a commercial device has yet been realized. This paper summarizes the current state of development of the technology in this field of research. First, the most adequate type of fuel cell for this application is discussed. The prototypes and design concepts of AUVs powered by fuel cells which have been developed in the last few years are described. Possible commercial and experimental fuel cell stack options are analyzed, examining solutions adopted in the analogous aerial vehicle applications, as well as the underwater ones, to see if integration in an AUV is feasible. Current solutions in oxygen and hydrogen storage systems are overviewed and energy density is objectively compared between battery power systems and fuel cell power systems for AUVs. A couple of system configuration solutions are described including the necessary lithium-ion battery hybrid system. Finally, some closing remarks on the future of this technology are given.

Spatial and temporal thermal characterization of stacked multicore architectures

Three-dimensional integration provides a new way of performance growth for microprocessor architectures. While a recent studies report promising performance improvement numbers, majority of the processor stacking options are thermally-limited. Elevated stack temperatures have significant effect on the overall energy efficiency and reliability of the processor; they also limit the potential peak performance improvement from the 3D implementation. Thermal characteristics of 3D stacks differ from 2D processors in various ways including: the nature of heat dissipation throughout the stack, thermal conductivity of the 3D structures such as micro-C4 layers, and hotspot interactions among layers. The intensity of the corresponding thermal problems is highly dependent on the 3D technology, processor and stack parameters. In this study we focus on spatial and temporal thermal characteristics of 3D multicore architectures using high-fidelity technology and processor models. Our experimental results highlight the need for integrating detailed thermal models in the design flow, starting with the early design stages. In addition, the reduced time constants and elevated on-chip temperatures indicate faster response time requirements for dynamic thermal management in processor stacking options.

Licklider Transmission Protocol (LTP)-Based DTN for Cislunar Communications

Delay/disruption-tolerant networking (DTN) technology offers a new solution to highly stressed communications in space environments, especially those with long link delay and frequent link disruptions in deep-space missions. To date, little work has been done in evaluating the performance of the available “convergence layer” protocols of DTN, especially the Licklider Transmission Protocol (LTP), when they are applied to an interplanetary Internet (IPN). In this paper, we present an experimental evaluation of the Bundle Protocol (BP) running over various “convergence layer” protocols in a simulated cislunar communications environment characterized by varying degrees of signal propagation delay and data loss. We focus on the LTP convergence layer (LTPCL) adapter running on top of UDP/IP (i.e., BP/LTPCL/UDP/IP). The performance of BP/LTPCL/UDP/IP in realistic file transfers over a PC-based network test bed is compared to that of two other DTN protocol stack options, BP/TCPCL/TCP/IP and BP/UDPCL/UDP/IP. A statistical method of t-test is also used for analysis of the experimental results. The experiment results show that LTPCL has a significant performance advantage over Transmission Control Protocol convergence layer (TCPCL) for link delays longer than 4000 ms regardless of the bit error rate (BER). For a very lossy channel with a BER of around 10-5, LTPCL has a significant goodput advantage over TCPCL at all the link delay levels studied, with an advantage of around 3000 B/s for delays longer than 1500 ms. LTPCL has a consistently significant goodput advantage over UDPCL, around 2500-3000 B/s, at all levels of link delays and BERs.

Gate Stack Influence on GIFBE in nFinFETs

The aim of this work is to study for the first time the gate induced floating body effect (GIFBE) of triple gate nFinFETs devices with different gate stack options for working function (WF) engineering. Based on electrical characterizations it is shown that the presence of a cap layer like Dy2O3 increases EOT and reduces the gate effective WF which decrease VFB and VT. As a consequence the transconductance also decreases and a positive shift of the onset of the GIFBE is observed both at room and at high temperature.