A High Capacity All Solid-State Li-Sulfur Battery Enabled by Conversion-Intercalation Hybrid Cathode Architecture

As demands for electrochemical energy storage continue to rise, alternative electrochemistries to conventional Li-ion batteries become more appealing. Here, an intercalation-conversion hybrid cathode that combines intercalation-type VS₂ with conversion-type sulfur chemistry to construct high performance solid-state lithium-sulfur batteries is reported. The layered VS₂ nanomaterial features Li-ion transport channels, metallic conductivity, and active capacity contribution, all of which provide an ideal platform for the solid state S/Li₂S redox couple to unlock its high gravimetric capacity. The S/VS₂/Li₃PS₄ hybrid cathode composite is prepared by a facile, low-cost, and low-energy mechanical blending process. The S/VS₂/Li₃PS₄|Li₃PS₄|Li/In (or Li) all-solid-state cell exhibits sulfur utilization of ≈85%, with a Coulombic efficiency of close to 100%. High areal capacity up to 7.8 mA h cm⁻² with an active material loading (S/VS₂) as high as 15.5 mg cm⁻² is achieved.     

Cu2O Nanocrystal‐Templated Growth of Cu2S Nanocages with Encapsulated Au Nanoparticles and In‐Situ Transmission X‐ray Microscopy Study

Cubic and octahedral Cu₂O nanocrystals and Au–Cu₂O core–shell heterostructures are used as sacrificial templates for the growth of Cu₂S nanocages and Au–Cu₂S core–cage structures. A rapid sulfidation process involving a surface reaction of Cu₂O nanocrystals with Na₂S, followed by etching of the Cu₂O cores with HCl solution for ≈5 sec, results in the fabrication of Cu₂S cages with a wall thickness of 10–20 nm. Transmission electron microscopy characterization reveals the formation of crystalline walls and the presence of ultrasmall pores with sizes of 1 nm or less. Formation of Cu₂O–Cu₂S core–shell structures and their conversion into Cu₂S cages is verified by UV–vis absorption spectroscopy. X‐ray photoelectron spectra further confirm the composition of the cages as Cu₂S. The entire hollowing process via the Kirkendall effect is recorded using in‐situ transmission X‐ray microscopy. After shell formation, continuous ionic diffusion removes the interior Cu₂O. Intermediate structures with remaining central Cu₂O portions and bridging arms to the surrounding cages are observed. The nanocages are also shown to allow molecular transport: anthracene and pyrene penetration into the cages leads to enhanced fluorescence quenching immediately upon adsorption onto the surfaces of the encapsulated gold nanocrystals.     

A Fully Synthesizable Bluetooth Baseband Module for a System‐on‐a‐Chip

Bluetooth is a specification for short‐range wireless communication using the 2.4 GHz ISM band. It emphasizes low complexity, low power, and low cost. This paper describes an area‐efficient digital baseband module for wireless technology. For area‐efficiency, we carefully consider hardware and software partitioning. We implement complex control tasks of the Bluetooth baseband layer protocols in software running on an embedded microcontroller. Hardware‐efficient functions, such as low‐level bitstream link control; host controller interfaces (HCIs), such as universal asynchronous receiver transmitter (UART) and universal serial bus (USB) interfaces; and audio Codec are performed by dedicated hardware blocks. Furthermore, we eliminate FIFOs for data buffering between hardware functional units. The design is done using fully synthesizable Verilog HDL to enhance the portability between process technologies so that our module can be easily integrated as an intellectual property core on system‐on‐a‐chip (SoC) ASICs. A field programmable gate array (FPGA) prototype of this module was tested for functional verification and realtime operation of file and bitstream transfers between PCs. The module was fabricated in a 0.25‐µm CMOS technology, the core size of which was only 2.79 mm×2.80 mm.     

Optimal Lattice-Reduction Aided Successive Interference Cancellation for MIMO Systems

In this letter, we investigated the optimal minimum-mean-squared-error (MMSE) based successive interference cancellation (SIC) strategy designed for lattice-reduction aided multiple-input multiple-output (MIMO) detectors. For the sake of generating the MMSE-based MIMO symbol estimate at each SIC detection stage, we model the so-called effective symbols generated with the aid of lattice-reduction as joint Gaussian distributed random variables. However, after lattice-reduction, the effective symbols become correlated and exhibit a non-zero mean. Hence, we derive the optimal MMSE SIC detector, which updates the mean and variance of the effective symbols at each SIC detection stage. As a result, the proposed detector achieves a better performance compared to its counterpart dispensing with updating the mean and variance, and performs close to the maximum likelihood detector.     

Multi‐band Approach to Deep Learning‐Based Artificial Stereo Extension

In this paper, an artificial stereo extension method that creates stereophonic sound from a mono sound source is proposed. The proposed method first trains deep neural networks (DNNs) that model the nonlinear relationship between the dominant and residual signals of the stereo channel. In the training stage, the band‐wise log spectral magnitude and unwrapped phase of both the dominant and residual signals are utilized to model the nonlinearities of each sub‐band through deep architecture. From that point, stereo extension is conducted by estimating the residual signal that corresponds to the input mono channel signal with the trained DNN model in a sub‐band domain. The performance of the proposed method was evaluated using a log spectral distortion (LSD) measure and multiple stimuli with a hidden reference and anchor (MUSHRA) test. The results showed that the proposed method provided a lower LSD and higher MUSHRA score than conventional methods that use hidden Markov models and DNN with full‐band processing.     

一种超粗化表面处理用于改善沉锡脱油的工艺探讨

沉锡工艺是一种代替传统热风整平的新型环保工艺,但沉锡工艺中的脱油问题一直是难以解决的问题,现通常方法是使用专用耐沉锡油墨或前处理使用超粗化药水处理板面,提高油墨和铜面的结合力,前两种方法的生产成本大大升高;本文根据现有的前处理方式,实验出适合沉锡使用的阻焊前处理方式,并列举该方式的具体应用。     

一个用于能量攫取系统的间歇式可调降压开关电容直流转换器

Energy harvesting systems stimulate the development of power management for low power consumption applications. Improving the converter efficiency of power management circuits has become a significant issue in energy harvesting system design. This paper presents a variable step-down conversion ratio switched capacitor （SC） DC-DC converter to advance the converter efficiency of charge on the stored capacitor in a wireless monitoring system of orthopedic implants. The converter is designed to work at 1 MHz switching frequency and achieves 15 to 2 V conversion. Measurement results show that the converter efficiency can reach 42% including all circuit power consumption, which is much higher than previous work.     

Lightweight and provably secure user authentication with anonymity for the global mobility network

Seamless roaming in the global mobility network (GLOMONET) is highly desirable for mobile users, although their proper authentication is challenging. This is because not only are wireless networks susceptible to attacks, but also mobile terminals have limited computational power. Recently, some authentication schemes with anonymity for the GLOMONET have been proposed. This paper shows some security weaknesses in those schemes. Furthermore, a lightweight and provably secure user authentication scheme with anonymity for the GLOMONET is proposed. It uses only symmetric cryptographic and hash operation primitives for secure authentication. Besides, it takes only four message exchanges among the user, foreign agent and home agent. We also demonstrate that this protocol enjoys important security attributes including prevention of various attacks, single registration, user anonymity, user friendly, no password/verifier table, and use of one‐time session key between mobile user and foreign agent. The security properties of the proposed protocol are formally validated by a model checking tool called AVISPA. Furthermore, as one of the new features in our protocol, it can defend smart card security breaches. Copyright © 2010 John Wiley & Sons, Ltd.