A Hybrid Domain Block Equalizer for Single-Carrier Modulated Systems

Poor performance in the presence of multipath with long delay spread has been considered as one of the main weaknesses of most single carrier modulated systems, including ATSC (advanced television systems committee) system. The introduction of distributed transmission network and single frequency network brings new challenges for the ATSC equalizer design, since the delay spread of a multipath channel under such scenarios becomes significantly longer than the traditional broadcasting practice of using one high power transmitter to cover a wide area, where the multipath distortion is mainly from reflected echoes. An iterative hybrid frequency-time domain equalizer for ATSC system is proposed in this paper based on our block-based interference analysis. The multipath distortion in the received ATSC signal is first tentatively removed with a frequency domain equalizer on a block-by-block basis. However, inter-block and intra-block interferences still exist due to the lack of cyclic structure in the received ATSC signal. A time domain interference cancellation algorithm is then used to cancel the inter-block interference and intra-carrier interference, based on the tentative decisions in time domain after the frequency domain equalization. These two steps are iterated until desired receiver performance is achieved. The proposed equalizer and the subsequent analysis are verified through numerical simulations.     

Response Characterization of Electroactive Polymers as Mechanical Sensors

The characterization of the dynamic response (including transfer function identification) of trilayer polypyrrole (PPy) type conducting polymer sensors is presented. The sensor was built like a cantilever beam with the free end stimulated through a mechanical lever system, which provided displacement inputs. The voltage generated and current passing between the two outer PPy layers as a result of the input was measured to model the output/input behavior of the sensors based on their experimental current/displacement and voltage/displacement frequency responses. We specifically targeted the low-frequency behavior of the sensor as it is a relatively slow system. Experimental transfer function models were generated and verified experimentally for sensors with different dimensions. The models can be used to understand the dynamic behavior and sensing ability of the polymers as mechanical sensors. The effect of the active sensor length on the voltage and current outputs has demonstrated that the shorter is the sensor length, the higher are the voltage output and the current passed for the same mechanical input. Also, their current and voltage responses under an impulse displacement stimulus were experimentally measured to show their dynamic sensing response and to estimate the current and voltage sensing bandwidths. Further, an energy balance method has been proposed to estimate the sensor output. Based on the novel experimental and analytical results, the contribution of this study is the first comprehensive investigation into the response analysis and characterization of the PPy-type conducting polymers as mechanical sensors, to the best of authors' knowledge.     

Benzodithiophene Hole‐Transporting Materials for Efficient Tin‐Based Perovskite Solar Cells

Developing efficient interfacial hole transporting materials (HTMs) is crucial for achieving high‐performance Pb‐free Sn‐based halide perovskite solar cells (PSCs). Here, a new series of benzodithiophene (BDT)‐based organic small molecules containing tetra‐ and di‐triphenyl amine donors prepared via a straightforward and scalable synthetic route is reported. The thermal, optical, and electrochemical properties of two BDT‐based molecules are shown to be structurally and energetically suitable to serve as HTMs for Sn‐based PSCs. It is reported here that ethylenediammonium/formamidinium tin iodide solar cells using BDT‐based HTMs deliver a champion power conversion efficiency up to 7.59%, outperforming analogous reference solar cells using traditional and expensive HTMs. Thus, these BDT‐based molecules are promising candidates as HTMs for the fabrication of high‐performance Sn‐based PSCs.     

Asymptotical Synchronization of Chaotic Lur’e Systems Under Time-Varying Sampling

This paper investigates the problem of sampled-data synchronization of chaotic Lur’e systems with time-varying sampling. A novel Lyapunov functional, which is continuous in time and makes full use of the available information about the sampling pattern, is constructed to synchronize the chaotic Lur’e systems. By using a free-weighting matrix approach and solving a set of linear matrix inequalities (LMIs), a sampled-data controller is obtained. The effectiveness and the validity of the proposed theoretical result are illustrated by two numerical examples.     

Adaptive Ionogel Paint from Room-Temperature Autonomous Polymerization of α-Thioctic Acid for Stretchable and Healable Electronics

Development of a universal stretchable ionic conductor coating on insulating substrates, irrespective of surface chemistry and substrate shapes, is of immense interest for compliant and integrative large-area electronics but has proved to be extremely challenging. Existing methods relying either on the concurrent deposition of polymerizing precursors or on divided formulation and painting processes both suffer from several limitations in terms of adhesion, dehydration, processability, and surface pre-treatment. Here an ionogel paint that is readily prepared from the concentration-induced autonomous ring-opening polymerization of a natural small molecule—α-thioctic acid (TA) at ambient conditions is reported. The presence of ionic liquid prevents polyTA from further depolymerization via forming COOH···OS hydrogen bonds, resulting in ultra-stretchable ionogels with widely tunable mechanical and conductive properties, self-healability, as well as tissue-like strain adaptability. Moreover, owing to its universal adhesion and adjustable rheology, the ionogel paint can be directly coated on diverse substrates with arbitrary shapes (including porous materials, 3D printed frames, and elastic threads) to render them ionic conductivity. Applications of the ionogel-coated substrates as skin-like highly sensitive and durable large-strain sensors are further demonstrated, suggesting the ionogel paint's great potential in the emerging soft and stretchable electronics.     

Bioinspired Supramolecular Slippery Organogels for Controlling Pathogen Spread by Respiratory Droplets

Surface-deposited pathogens are sources for the spread of infectious diseases. Protecting public facilities with a replaceable or recyclable antifouling coating is a promising approach to control pathogen transmission. However, most antifouling coatings are less effective in preventing pathogen-contained respiratory droplets because these tiny droplets are difficult to repel, and the deposited pathogens can remain viable from hours to days. Inspired by mucus, an antimicrobial supramolecular organogel for the control of microdroplet-mediated pathogen spread is developed. The developed organogel coating harvests a couple of unique features including localized molecular control-release, readily damage healing, and persistent fouling-release properties, which are preferential for antifouling coating. Microdroplets deposited on the organogel surfaces will be spontaneously wrapped with a thin liquid layer, and will therefore be disinfected rapidly due to a mechanism of spatially enhanced release of bactericidal molecules. Furthermore, the persistent fouling-release and damage-healing properties will significantly extend the life-span of the coating, making it promising for diverse applications.     

Testing of Synchronizers in Asynchronous FIFO

This paper presents a test method for testing two-D-flip-flop synchronizers in an asynchronous first-in-first-out (FIFO) interface. A faulty synchronizer can have different fault behaviors depending on the input application time, the fault location, the fault mechanism, and the applied clock frequency. The proposed test method can apply the input patterns at different time and generate capture clock signals with different frequency regardless of phase-locked loop (PLL) of the design. To implement the proposed test method, channel delay compensator, delayed scan enable signal generator, launch clock generator, and capture clock generator are designed. In addition, a well-designed calibration method is proposed to calibrate all programmable delay elements used in the test circuits. The proposed test method evolves to several test sections to detect all possible faults of the two-D-flip-flop synchronizers in the asynchronous FIFO interface.     

Cryptanalysis of an extended MQ signature system HTTM

Since Multivatriate Quadratic （MQ）-based Public Key Cryptosystem （MPKC） has been one of the hot research fields of post-quantum cryptography, it becomes important to analyze the security of new MPKC schemes. Wang et al. proposed a novel multivariate signature scheme with Hash-based Tame Transformation and Minus （HTTM） in 2011. For this extended MQ-based signature, we can transform it into an SFLASH variant by splitting and merging HT transformation, and solve an equivalent private key corresponding to the public key of HTTM. Thus, the adversary can forge legitimate signature for any message by using this equivalent private key.     

高压变频器在洗煤厂介质泵上的应用

本文介绍了风光牌高压变频器在新疆伊犁钢铁有限责任公司洗煤厂介质泵的应用情况,对应用案例进行了介绍。结果表明,在洗煤厂介质泵上采用高压变频器具有较高的经济效益和社会效益。     

Hierarchical Ordered Dual‐Mesoporous Polypyrrole/Graphene Nanosheets as Bi‐Functional Active Materials for High‐Performance Planar Integrated System of Micro‐Supercapacitor and Gas Sensor

Planar integrated systems of micro‐supercapacitors (MSCs) and sensors are of profound importance for 3C electronics, but usually appear poor in compatibility due to the complex connections of device units with multiple mono‐functional materials. Herein, 2D hierarchical ordered dual‐mesoporous polypyrrole/graphene (DM‐PG) nanosheets are developed as bi‐functional active materials for a novel prototype planar integrated system of MSC and NH₃ sensor. Owing to effective coupling of conductive graphene and high‐sensitive pseudocapacitive polypyrrole, well‐defined dual‐mesopores of ≈7 and ≈18 nm, hierarchical mesoporous network, and large surface area of 112 m² g^?1, the resultant DM‐PG nanosheets exhibit extraordinary sensing response to NH₃ as low as 200 ppb, exceptional selectivity toward NH₃ that is much higher than other volatile organic compounds, and outstanding capacitance of 376 F g^?1 at 1 mV s^?1 for supercapacitors, simultaneously surpassing single‐mesoporous and non‐mesoporous counterparts. Importantly, the bi‐functional DM‐PG‐based MSC‐sensor integrated system represents rapid and stable response exposed to 10–40 ppm of NH₃ after only charging for 100 s, remarkable sensitivity of NH₃ detection that is close to DM‐PG‐based MSC‐free sensor, impressive flexibility with ≈82% of initial response value even at 180°, and enhanced overall compatibility, thereby holding great promise for ultrathin, miniaturized, body‐attachable, and portable detection of NH₃.