Crystallization of 2D Hybrid Organic–Inorganic Perovskites Templated by Conductive Substrates

2D hybrid organic–inorganic perovskites are valued in optoelectronic applications for their tunable bandgap and excellent moisture and irradiation stability. These properties stem from both the chemical composition and crystallinity of the layer formed. Defects in the lattice, impurities, and crystal grain boundaries generally introduce trap states and surface energy pinning, limiting the ultimate performance of the perovskite; hence, an in-depth understanding of the crystallization process is indispensable. Here, a kinetic and thermodynamic study of 2D perovskite layer crystallization on transparent conductive substrates are provided—fluorine-doped tin oxide and graphene. Due to markedly different surface structure and chemistry, the two substrates interact differently with the perovskite layer. A time-resolved grazing-incidence wide-angle X-ray scattering (GIWAXS) is used to monitor the crystallization on the two substrates. Molecular dynamics simulations are employed to explain the experimental data and to rationalize the perovskite layer formation. The findings assist substrate selection based on the required film morphology, revealing the structural dynamics during the crystallization process, thus helping to tackle the technological challenges of structure formation of 2D perovskites for optoelectronic devices.     

Efficient Parallelization of Polyphase Arbitrary Resampling FIR Filters for High-Speed Applications

This article describes a method for increasing the sampling rate of efficient polyphase arbitrary resampling FIR filters. An FPGA proof of concept prototype of this architecture has been implemented in a Xilinx Kintex-7 FPGA which is able to convert the sampling rate of a signal from 500 MHz to 600 MHz. This article compares this new architecture with other best known efficient resampling architectures implemented on the same FPGA. The area usage on the FPGA shows that our proposed implementation is very proficient in high bandwidth applications without requiring significantly more resources on the FPGA. A theoretical calculation of the resampling error introduced on a modulated data stream is provided to evaluate the new architecture against other existing resampling architectures.     

Une architecture massivement parallèle intégrée

This paper presents a new massively parallel MIMD architecture, halfway between the Connection Machine and hypercubes based on 32-bit processors. It is built from specific 8-bit processors arranged in a 2-D grid and communicating by message transfers. We discuss the communication problems, the instruction set of the basic processing unit, the programmation of the whole array and the use of a high level data-flow language.     

Large modulation depth, single-moded quantum well waveguide modulator operating around 1.57 mu m

The performance of long wavelength single-mode waveguide modulators suitable for monolithic integration with a quantum well laser is reported. The device operated between 1.560 mu m and 1.570 mu m. The guiding layer was formed by a 0.27 mu m quaternary layer at the centre of which were four 50 AA In/sub 0.53/Ga/sub 0.47/As quantum wells separated by 100 AA InP barrier layers. Lateral confinement was obtained by etching ridges in the top InP contact layer. For devices of 500 mu m length, a modulation depth of 19 dB was obtained at a wavelength of 1.568 mu m with a reverse bias voltage of only 3 V and an internal loss of 2.5 dB.<>     

Dynamics of the transient buildup of emission inNd3+-doped fiber lasers

The two-stage process of the transient buildup of emission in Nd ⁴⁺-doped fiber lasers is described both experimentally and theoretically. After switching on the pump, spontaneous emission increases first until the gain becomes sufficient to compensate for the cavity losses; the laser field then develops and reaches the steady state after more or less regular oscillations. During this second stage, an almost chaotic spiking is obtained either for high pumping rates and/or at low temperatures. The whole set of these dynamical scenarios is not described under the usual assumptions of uniform cavity losses over the whole field spectrum and of pure homogeneous broadening for the transition line, but rather a modified form of the Maxwell-Bloch equations which retains some frequency dependence for the losses in the cavity and the inhomogeneous broadening as well is proposed     

继电器触点回跳消除电路

半导体技术的进展已使集成电路(IC)能够取代很多机械式继电器,但在任意极性的高电压大电流电路中,继电器仍然占据主导地位.然而,这类继电器的触点回跳会给下游电路带来麻烦.解决触点回跳的一种办法是把继电器与一个热插拔控制器结合起来.     

Exploring time series retrieved from cardiac implantable devices for optimizing patient follow-up

Current cardiac implantable devices (IDs) are equipped with a set of sensors that can provide useful information to improve patient follow-up and prevent health deterioration in the postoperative period. In this paper, data obtained from an ID with two such sensors (a transthoracic impedance sensor and an accelerometer) are analyzed in order to evaluate their potential application for the follow-up of patients treated with a cardiac resynchronization therapy (CRT). A methodology combining spatiotemporal fuzzy coding and multiple correspondence analysis (MCA) is applied in order to: 1) reduce the dimensionality of the data and provide new synthetic indexes based on the "factorial axes" obtained from MCA; 2) interpret these factorial axes in physiological terms; and 3) analyze the evolution of the patient's status by projecting the acquired data into the plane formed by the first two factorial axes named "factorial plane." In order to classify the different evolution patterns, a new similarity measure is proposed and validated on the simulated datasets, and then, used to cluster observed data from 41 CRT patients. The obtained clusters are compared with the annotations on each patient's medical record. Two areas on the factorial plane are identified, one being correlated with a health degradation of patients and the other with a stable clinical state.     

爱特梅尔基于ARM Cortex-M3微控制器嵌入信号完整性解决方案

由于低功耗领域(手持式或工业应用)的消费者要求产品在更小的PCB尺寸上提供更高的性能,故工程师必须提高这些应用产品的电路密度,经常需要设计带有公用电源轨的数字、模拟和传感器电路,以节省空间,并满足EMI要求.     

Une nouvelle architecture de gestion de réseaux DiffServ basée sur la technologie de réseau actif et la gestion à base de règles

The objective of this work is to propose an architectural solution to the very complex problem of DiffServ network management and control. Despite the fact that DiffServ offers a scalable QoS provisioning solution, it introduces a high complexity in term of its deployment due to the number of complex configurations to perform in the highly distributed and heterogeneous network environment. The proposed solution aims to take benefit from the scalability and flexibility properties of Active Network technology for distributing the control in large scale as well as the autonomic property of Policy Based Management to automate the distribution of these tasks in the operator network. This solution constitutes an alternative to the client/server approach generally used.     

Large-scale biomedical image analysis in grid environments

This paper presents the application of a component-based Grid middleware system for processing extremely large images obtained from digital microscopy devices. We have developed parallel, out-of-core techniques for different classes of data processing operations employed on images from confocal microscopy scanners. These techniques are combined into a data preprocessing and analysis pipeline using the component-based middleware system. The experimental results show that: 1) our implementation achieves good performance and can handle very large datasets on high-performance Grid nodes, consisting of computation and/or storage clusters and 2) it can take advantage of Grid nodes connected over high-bandwidth wide-area networks by combining task and data parallelism.