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Showing papers by "Southeast University published in 2017"


Journal ArticleDOI
TL;DR: This work combines the autoencoder, deconvolution network, and shortcut connections into the residual encoder–decoder convolutional neural network (RED-CNN) for low-dose CT imaging and achieves a competitive performance relative to the-state-of-art methods in both simulated and clinical cases.
Abstract: Given the potential risk of X-ray radiation to the patient, low-dose CT has attracted a considerable interest in the medical imaging field. Currently, the main stream low-dose CT methods include vendor-specific sinogram domain filtration and iterative reconstruction algorithms, but they need to access raw data, whose formats are not transparent to most users. Due to the difficulty of modeling the statistical characteristics in the image domain, the existing methods for directly processing reconstructed images cannot eliminate image noise very well while keeping structural details. Inspired by the idea of deep learning, here we combine the autoencoder, deconvolution network, and shortcut connections into the residual encoder–decoder convolutional neural network (RED-CNN) for low-dose CT imaging. After patch-based training, the proposed RED-CNN achieves a competitive performance relative to the-state-of-art methods in both simulated and clinical cases. Especially, our method has been favorably evaluated in terms of noise suppression, structural preservation, and lesion detection.

1,161 citations


Journal ArticleDOI
TL;DR: The purpose of this review is to convey the fundamentals of droplet microfluidics, a critical analysis on its current status and challenges, and opinions on its future development.
Abstract: Droplet microfluidics generates and manipulates discrete droplets through immiscible multiphase flows inside microchannels Due to its remarkable advantages, droplet microfluidics bears significant value in an extremely wide range of area In this review, we provide a comprehensive and in-depth insight into droplet microfluidics, covering fundamental research from microfluidic chip fabrication and droplet generation to the applications of droplets in bio(chemical) analysis and materials generation The purpose of this review is to convey the fundamentals of droplet microfluidics, a critical analysis on its current status and challenges, and opinions on its future development We believe this review will promote communications among biology, chemistry, physics, and materials science

990 citations


Journal ArticleDOI
TL;DR: A comprehensive survey of mmWave communications for future mobile networks (5G and beyond) is presented, including an overview of the solution for multiple access and backhauling, followed by the analysis of coverage and connectivity.
Abstract: Millimeter wave (mmWave) communications have recently attracted large research interest, since the huge available bandwidth can potentially lead to the rates of multiple gigabit per second per user Though mmWave can be readily used in stationary scenarios, such as indoor hotspots or backhaul, it is challenging to use mmWave in mobile networks, where the transmitting/receiving nodes may be moving, channels may have a complicated structure, and the coordination among multiple nodes is difficult To fully exploit the high potential rates of mmWave in mobile networks, lots of technical problems must be addressed This paper presents a comprehensive survey of mmWave communications for future mobile networks (5G and beyond) We first summarize the recent channel measurement campaigns and modeling results Then, we discuss in detail recent progresses in multiple input multiple output transceiver design for mmWave communications After that, we provide an overview of the solution for multiple access and backhauling, followed by the analysis of coverage and connectivity Finally, the progresses in the standardization and deployment of mmWave for mobile networks are discussed

887 citations


Journal ArticleDOI
TL;DR: The selection of appropriate biomaterials and fabrication methods to prepare novel injectable hydrogels for cartilage and bone tissue engineering are described and the biology of Cartilage and the bony ECM is summarized.
Abstract: Tissue engineering has become a promising strategy for repairing damaged cartilage and bone tissue Among the scaffolds for tissue-engineering applications, injectable hydrogels have demonstrated great potential for use as three-dimensional cell culture scaffolds in cartilage and bone tissue engineering, owing to their high water content, similarity to the natural extracellular matrix (ECM), porous framework for cell transplantation and proliferation, minimal invasive properties, and ability to match irregular defects In this review, we describe the selection of appropriate biomaterials and fabrication methods to prepare novel injectable hydrogels for cartilage and bone tissue engineering In addition, the biology of cartilage and the bony ECM is also summarized Finally, future perspectives for injectable hydrogels in cartilage and bone tissue engineering are discussed

782 citations


Journal ArticleDOI
TL;DR: Ti2 O3 nanoparticles with high performance of photothermal conversion are demonstrated for the first time and shows potential use in seawater desalination and purification.
Abstract: Ti2 O3 nanoparticles with high performance of photothermal conversion are demonstrated for the first time. Benefiting from the nanosize and narrow-bandgap features, the Ti2 O3 nanoparticles possess strong light absorption and nearly 100% internal solar-thermal conversion efficiency. Furthermore, Ti2 O3 -nanoparticle-based thin film shows potential use in seawater desalination and purification.

755 citations


Journal ArticleDOI
TL;DR: This paper provides an overview of the existing multibeam antenna technologies which include the passiveMultibeam antennas (MBAs) based on quasi-optical components and beamforming circuits, multibeams phased-array antennas enabled by various phase-shifting methods, and digital MBAs with different system architectures.
Abstract: With the demanding system requirements for the fifth-generation (5G) wireless communications and the severe spectrum shortage at conventional cellular frequencies, multibeam antenna systems operating in the millimeter-wave frequency bands have attracted a lot of research interest and have been actively investigated. They represent the key antenna technology for supporting a high data transmission rate, an improved signal-to-interference-plus-noise ratio, an increased spectral and energy efficiency, and versatile beam shaping, thereby holding a great promise in serving as the critical infrastructure for enabling beamforming and massive multiple-input multiple-output (MIMO) that boost the 5G. This paper provides an overview of the existing multibeam antenna technologies which include the passive multibeam antennas (MBAs) based on quasi-optical components and beamforming circuits, multibeam phased-array antennas enabled by various phase-shifting methods, and digital MBAs with different system architectures. Specifically, their principles of operation, design, and implementation, as well as a number of illustrative application examples are reviewed. Finally, the suitability of these MBAs for the future 5G massive MIMO wireless systems as well as the associated challenges is discussed.

737 citations


Journal ArticleDOI
TL;DR: The proposed reprogrammable hologram may be a key in enabling future intelligent devices with reconfigurable and programmable functionalities that may lead to advances in a variety of applications such as microscopy, display, security, data storage, and information processing.
Abstract: Metasurfaces have enabled a plethora of emerging functions within an ultrathin dimension, paving way towards flat and highly integrated photonic devices. Despite the rapid progress in this area, simultaneous realization of reconfigurability, high efficiency, and full control over the phase and amplitude of scattered light is posing a great challenge. Here, we try to tackle this challenge by introducing the concept of a reprogrammable hologram based on 1-bit coding metasurfaces. The state of each unit cell of the coding metasurface can be switched between ‘1’ and ‘0’ by electrically controlling the loaded diodes. Our proof-of-concept experiments show that multiple desired holographic images can be realized in real time with only a single coding metasurface. The proposed reprogrammable hologram may be a key in enabling future intelligent devices with reconfigurable and programmable functionalities that may lead to advances in a variety of applications such as microscopy, display, security, data storage, and information processing. Realizing metasurfaces with reconfigurability, high efficiency, and control over phase and amplitude is a challenge. Here, Li et al. introduce a reprogrammable hologram based on a 1-bit coding metasurface, where the state of each unit cell of the coding metasurface can be switched electrically.

737 citations


Journal ArticleDOI
21 Jul 2017-Science
TL;DR: Trimethylchloromethyl ammonium trichloromanganese(II), an organic-inorganic perovskite ferroelectric crystal processed from aqueous solution, has a large d33 of 185 picocoulombs per newton and a high phase-transition temperature of 406 kelvin (K) (16 K above that of BTO), which makes it a competitive candidate for medical, micromechanical, and biomechanical applications.
Abstract: Molecular piezoelectrics are highly desirable for their easy and environment-friendly processing, light weight, low processing temperature, and mechanical flexibility. However, although 136 years have passed since the discovery in 1880 of the piezoelectric effect, molecular piezoelectrics with a piezoelectric coefficient d33 comparable with piezoceramics such as barium titanate (BTO; ~190 picocoulombs per newton) have not been found. We show that trimethylchloromethyl ammonium trichloromanganese(II), an organic-inorganic perovskite ferroelectric crystal processed from aqueous solution, has a large d33 of 185 picocoulombs per newton and a high phase-transition temperature of 406 kelvin (K) (16 K above that of BTO). This makes it a competitive candidate for medical, micromechanical, and biomechanical applications.

644 citations


Journal ArticleDOI
TL;DR: Zhao et al. as mentioned in this paper presented a certified 17% efficient tin and lead perovskite solar cell, which is integrated as the lowbandgap component of a tandem device with 21% efficiency.
Abstract: Tandem solar cells using only metal-halide perovskite sub-cells are an attractive choice for next-generation solar cells. However, the progress in developing efficient all-perovskite tandem solar cells has been hindered by the lack of high-performance low-bandgap perovskite solar cells. Here, we report efficient mixed tin–lead iodide low-bandgap (∼1.25 eV) perovskite solar cells with open-circuit voltages up to 0.85 V and over 70% external quantum efficiencies in the infrared wavelength range of 700–900 nm, delivering a short-circuit current density of over 29 mA cm−2 and demonstrating suitability for bottom-cell applications in all-perovskite tandem solar cells. Our low-bandgap perovskite solar cells achieve a maximum power conversion efficiency of 17.6% and a certified efficiency of 17.01% with a negligible current–voltage hysteresis. When mechanically stacked with a ∼1.58 eV bandgap perovskite top cell, our best all-perovskite 4-terminal tandem solar cell shows a steady-state efficiency of 21.0%. All-perovskite tandem solar cells hold the promise of high efficiencies whilst safeguarding the ease of fabrication intrinsic to perovskites. Here, Zhao et al. present a certified 17% efficient tin and lead perovskite solar cell, which is integrated as the low-bandgap component of a tandem device with 21% efficiency.

590 citations


Journal ArticleDOI
TL;DR: This work introduces a recurrent deep neural network for real-time financial signal representation and trading and proposes a task-aware backpropagation through time method to cope with the gradient vanishing issue in deep training.
Abstract: Can we train the computer to beat experienced traders for financial assert trading? In this paper, we try to address this challenge by introducing a recurrent deep neural network (NN) for real-time financial signal representation and trading. Our model is inspired by two biological-related learning concepts of deep learning (DL) and reinforcement learning (RL). In the framework, the DL part automatically senses the dynamic market condition for informative feature learning. Then, the RL module interacts with deep representations and makes trading decisions to accumulate the ultimate rewards in an unknown environment. The learning system is implemented in a complex NN that exhibits both the deep and recurrent structures. Hence, we propose a task-aware backpropagation through time method to cope with the gradient vanishing issue in deep training. The robustness of the neural system is verified on both the stock and the commodity future markets under broad testing conditions.

522 citations


Journal ArticleDOI
30 Jan 2017-Sensors
TL;DR: A deep neural network structure named Convolutional Bi-directional Long Short-Term Memory networks (CBLSTM) has been designed here to address raw sensory data and is able to outperform several state-of-the-art baseline methods.
Abstract: In modern manufacturing systems and industries, more and more research efforts have been made in developing effective machine health monitoring systems. Among various machine health monitoring approaches, data-driven methods are gaining in popularity due to the development of advanced sensing and data analytic techniques. However, considering the noise, varying length and irregular sampling behind sensory data, this kind of sequential data cannot be fed into classification and regression models directly. Therefore, previous work focuses on feature extraction/fusion methods requiring expensive human labor and high quality expert knowledge. With the development of deep learning methods in the last few years, which redefine representation learning from raw data, a deep neural network structure named Convolutional Bi-directional Long Short-Term Memory networks (CBLSTM) has been designed here to address raw sensory data. CBLSTM firstly uses CNN to extract local features that are robust and informative from the sequential input. Then, bi-directional LSTM is introduced to encode temporal information. Long Short-Term Memory networks(LSTMs) are able to capture long-term dependencies and model sequential data, and the bi-directional structure enables the capture of past and future contexts. Stacked, fully-connected layers and the linear regression layer are built on top of bi-directional LSTMs to predict the target value. Here, a real-life tool wear test is introduced, and our proposed CBLSTM is able to predict the actual tool wear based on raw sensory data. The experimental results have shown that our model is able to outperform several state-of-the-art baseline methods.

Journal ArticleDOI
TL;DR: This paper presents a comprehensive overview of the emerging studies on DL-based physical layer processing, including leveraging DL to redesign a module of the conventional communication system and replace the communication system with a radically new architecture based on an autoencoder.
Abstract: Machine learning (ML) has been widely applied to the upper layers of wireless communication systems for various purposes, such as deployment of cognitive radio and communication network. However, its application to the physical layer is hampered by sophisticated channel environments and limited learning ability of conventional ML algorithms. Deep learning (DL) has been recently applied for many fields, such as computer vision and natural language processing, given its expressive capacity and convenient optimization capability. The potential application of DL to the physical layer has also been increasingly recognized because of the new features for future communications, such as complex scenarios with unknown channel models, high speed and accurate processing requirements; these features challenge conventional communication theories. This paper presents a comprehensive overview of the emerging studies on DL-based physical layer processing, including leveraging DL to redesign a module of the conventional communication system (for modulation recognition, channel decoding, and detection) and replace the communication system with a radically new architecture based on an autoencoder. These DL-based methods show promising performance improvements but have certain limitations, such as lack of solid analytical tools and use of architectures that are specifically designed for communication and implementation research, thereby motivating future research in this field.

Journal ArticleDOI
TL;DR: In this article, spontaneous parity and topological edge states are observed in a photonic non-Hermitian system with a quantum walk interferometer, where topological parity is achieved by time symmetry breaking.
Abstract: Spontaneous parity–time-symmetry breaking and topological edge states are observed in a photonic non-Hermitian system — a quantum walk interferometer.

Journal ArticleDOI
TL;DR: The TODIM (an acronym in Portuguese of interactive and multi-criteria decision making) technique is extended to solve MCGDM problems within the context of interval type-2 fuzzy sets (IT2FSs) and presented its application to green supplier selection problem.

Journal ArticleDOI
TL;DR: A spatial basis expansion model (SBEM) is built to represent the UL/DL channels with far fewer parameter dimensions, which significantly reduces the training overhead and feedback cost and enhances the spectral efficiency.
Abstract: This paper proposes a unified transmission strategy for multiuser time division duplex (TDD)/frequency division duplex (FDD) massive multiple-input–multiple-output (MIMO) systems, including uplink (UL)/downlink (DL) channel estimation and user scheduling for data transmission. With the aid of antenna array theory and array signal processing, we build a spatial basis expansion model (SBEM) to represent the UL/DL channels with far fewer parameter dimensions. Hence, both the UL and DL channel estimations of multiusers can be carried out with a small amount of training resource, which significantly reduces the training overhead and feedback cost. Meanwhile, the pilot contamination problem in the UL training is immediately relieved by exploiting the spatial information of users. To enhance the spectral efficiency, we also design a greedy user scheduling scheme during the data transmission period. Compared with existing low-rank models, the newly proposed SBEM offers an alternative for channel acquisition without the need for channel statistics and can be applied to both TDD and FDD systems. Various numerical results are provided to corroborate the proposed studies.

Journal ArticleDOI
TL;DR: In this paper, the authors expose a link between electron-vibrations coupling and non-radiative recombinations, derive a new limit for the efficiency of organic solar cells, and redefine their optimal optical gap.
Abstract: The conversion efficiency of organic solar cells suffers from their low open-circuit voltages. Here, the authors expose a link between electron-vibrations coupling and non-radiative recombinations, derive a new limit for the efficiency of organic solar cells, and redefine their optimal optical gap.

Journal ArticleDOI
TL;DR: A better understanding of the mutual interactions of the microbiota and host immune system, would shed light on the endeavors of disease prevention and broaden the path to the discovery of immune intervention targets for disease treatment.
Abstract: A vast diversity of microbes colonizes in the human gastrointestinal tract, referred to intestinal microbiota. Microbiota and products thereof are indispensable for shaping the development and function of host innate immune system, thereby exerting multifaceted impacts in gut health. This paper reviews the effects on immunity of gut microbe-derived nucleic acids, and gut microbial metabolites, as well as the involvement of commensals in the gut homeostasis. We focus on the recent findings with an intention to illuminate the mechanisms by which the microbiota and products thereof are interacting with host immunity, as well as to scrutinize imbalanced gut microbiota (dysbiosis) which lead to autoimmune disorders including inflammatory bowel disease (IBD), Type 1 diabetes (T1D) and systemic immune syndromes such as rheumatoid arthritis (RA). In addition to their well-recognized benefits in the gut such as occupation of ecological niches and competition with pathogens, commensal bacteria have been shown to strengthen the gut barrier and to exert immunomodulatory actions within the gut and beyond. It has been realized that impaired intestinal microbiota not only contribute to gut diseases but also are inextricably linked to metabolic disorders and even brain dysfunction. A better understanding of the mutual interactions of the microbiota and host immune system, would shed light on our endeavors of disease prevention and broaden the path to our discovery of immune intervention targets for disease treatment.

Journal ArticleDOI
27 Jul 2017-ACS Nano
TL;DR: Graphene electronic tattoo sensors that are made of graphene are reported, which have been successfully applied to measure electrocardiogram (ECG), electromyogram (EMG), electroencephalogram (EEG), skin temperature, and skin hydration.
Abstract: Tattoo-like epidermal sensors are an emerging class of truly wearable electronics, owing to their thinness and softness. While most of them are based on thin metal films, a silicon membrane, or nanoparticle-based printable inks, we report sub-micrometer thick, multimodal electronic tattoo sensors that are made of graphene. The graphene electronic tattoo (GET) is designed as filamentary serpentines and fabricated by a cost- and time-effective “wet transfer, dry patterning” method. It has a total thickness of 463 ± 30 nm, an optical transparency of ∼85%, and a stretchability of more than 40%. The GET can be directly laminated on human skin just like a temporary tattoo and can fully conform to the microscopic morphology of the surface of skin via just van der Waals forces. The open-mesh structure of the GET makes it breathable and its stiffness negligible. A bare GET is able to stay attached to skin for several hours without fracture or delamination. With liquid bandage coverage, a GET may stay functional on...

Journal ArticleDOI
Zhuyuan Wang1, Shenfei Zong1, Lei Wu1, Dan Zhu1, Yiping Cui1 
TL;DR: Focusing on several basic elements in SERS immunoassays, typical structures of SERS nanoprobes, productive optical spectral encoding strategies, and popular immunoASSay platforms are highlighted, followed by their representative biological applications in the last 5 years.
Abstract: Owing to their excellent multiplexing ability, high sensitivity, and large dynamic range, immunoassays using surface-enhanced Raman scattering (SERS) as the readout signal have found prosperous applications in fields such as disease diagnosis, environmental surveillance, and food safety supervision. Various ever-increasing demands have promoted SERS-based immunoassays from the classical sandwich-type ones to those integrated with fascinating automatic platforms (e.g., test strips and microfluidic chips). As recent years have witnessed impressive progress in SERS immunoassays, we try to comprehensively cover SERS-based immunoassays from their basic working principles to specific applications. Focusing on several basic elements in SERS immunoassays, typical structures of SERS nanoprobes, productive optical spectral encoding strategies, and popular immunoassay platforms are highlighted, followed by their representative biological applications in the last 5 years. Moreover, despite the vast advances achieved ...

Journal ArticleDOI
TL;DR: In vitro and in vivo experiments disclose that Ti3C2-DOX shows enhanced biocompatibility, tumor specific accumulation, and stimuli-responsive drug release behavior and achieve effective cancer cell killing and tumor tissue destruction through photothermal/photodynamic/chemo synergistic therapy.
Abstract: Ti3C2 MXene is a new two-dimensional material exhibiting a variety of novel properties including good photothermal effect, and the capability of Ti3C2 for multimodal tumor therapy is in urgent need of development. Herein, ultrathin Ti3C2 MXene nanosheets (∼100 nm) have been synthesized by supplying additive Al3+ to avoid Al loss and employed as a photothermal/photodynamic agent for cancer therapy. The as-obtained nanosheets exhibit outstanding mass extinction coefficient (28.6 Lg–1 cm–1 at 808 nm), superior photothermal conversion efficiency (∼58.3%), and effective singlet oxygen generation (1O2) upon 808 nm laser irradiation. Based on these Ti3C2 nanosheets, a multifunctional nanoplatform (Ti3C2-DOX) is established via layer-by-layer surface modification with doxorubicin (DOX) and hyaluronic acid (HA). In vitro and in vivo experiments disclose that Ti3C2-DOX shows enhanced biocompatibility, tumor specific accumulation, and stimuli-responsive drug release behavior and achieve effective cancer cell killing...

Journal ArticleDOI
TL;DR: When dealing with uncertainties, it is shown that DUEA has a different but complementary mechanism to widely used robust control and adaptive control and other promising methods such as internal model control and output regulation theory.
Abstract: This paper gives a comprehensive overview on disturbance/uncertainty estimation and attenuation (DUEA) techniques in permanent-magnet synchronous motor (PMSM) drives. Various disturbances and uncertainties in PMSM and also other alternating current (ac) motor drives are first reviewed which shows they have different behaviors and appear in different control loops of the system. The existing DUEA and other relevant control methods in handling disturbances and uncertainties widely used in PMSM drives, and their latest developments are then discussed and summarized. It also provides in-depth analysis of the relationship between these advanced control methods in the context of PMSM systems. When dealing with uncertainties, it is shown that DUEA has a different but complementary mechanism to widely used robust control and adaptive control. The similarities and differences in disturbance attenuation of DUEA and other promising methods such as internal model control and output regulation theory have been analyzed in detail. The wide applications of these methods in different ac motor drives (in particular in PMSM drives) are categorized and summarized. Finally, the paper ends with the discussion on future directions in this area.

Posted Content
TL;DR: In this article, a novel CSI sensing and recovery network that learns to effectively use channel structure from training samples is proposed. But, the CSI reconstruction quality is not significantly improved compared with existing compressive sensing (CS)-based methods.
Abstract: In frequency division duplex mode, the downlink channel state information (CSI) should be conveyed to the base station through feedback links so that the potential gains of a massive multiple-input multiple-output can be exhibited. However, the excessive feedback overhead remains a bottleneck in this regime. In this letter, we use beep learning technology to develop CsiNet, a novel CSI sensing and recovery network that learns to effectively use channel structure from training samples. In particular, CsiNet learns a transformation from CSI to a near-optimal number of representations (codewords) and an inverse transformation from codewords to CSI. Experiments demonstrate that CsiNet can recover CSI with significantly improved reconstruction quality compared with existing compressive sensing (CS)-based methods. Even at excessively low compression regions where CS-based methods cannot work, CsiNet retains effective beamforming gain.

Journal ArticleDOI
TL;DR: It is shown that modified exosomes, with rabies virus glycoprotein fused to exosomal protein lysosome-associated membrane glycop Protein 2b (Lamp2b), could efficiently deliver miR-124 to the infarct site and suggests that RVG-exosomes can be utilized therapeutically for the targeted delivery of gene drugs to the brain, thus having great potential for clinical applications.
Abstract: The intrinsic ability of neurogenesis after stroke has been proven weak, which results in insufficient repair of injury in the nerve system. Recent studies suggest multiple microRNAs (miRNAs) are involved in the neuroremodeling process. Targeted miRNAs delivery for amplification of neurogenesis is promising in promoting the prognosis after ischemia. Here, we showed that modified exosomes, with rabies virus glycoprotein (RVG) fused to exosomal protein lysosome-associated membrane glycoprotein 2b (Lamp2b), could efficiently deliver miR-124 to the infarct site. Systemic administration of RVG-exosomes loaded with miR-124 promoted cortical neural progenitors to obtain neuronal identity and protect against ischemic injury by robust cortical neurogenesis. Our study suggests that RVG-exosomes can be utilized therapeutically for the targeted delivery of gene drugs to the brain, thus having great potential for clinical applications.

Journal ArticleDOI
TL;DR: A novel Sb@C nanosphere anode with biomimetic yolk-shell structure for Li/Na-ion batteries via a nanoconfined galvanic replacement route and maintains a reversible capacity of approximate 280 mAh g-1 at 1000 mA g- 1 after 200 cycles.
Abstract: In the current research project, we have prepared a novel Sb@C nanosphere anode with biomimetic yolk–shell structure for Li/Na-ion batteries via a nanoconfined galvanic replacement route. The yolk–shell microstructure consists of Sb hollow yolk completely protected by a well-conductive carbon thin shell. The substantial void space in the these hollow Sb@C yolk–shell particles allows for the full volume expansion of inner Sb while maintaining the framework of the Sb@C anode and developing a stable SEI film on the outside carbon shell. As for Li-ion battery anode, they displayed a large specific capacity (634 mAh g–1), high rate capability (specific capabilities of 622, 557, 496, 439, and 384 mAh g–1 at 100, 200, 500, 1000, and 2000 mA g–1, respectively) and stable cycling performance (a specific capacity of 405 mAh g–1 after long 300 cycles at 1000 mA g–1). As for Na-ion storage, these yolk–shell Sb@C particles also maintained a reversible capacity of approximate 280 mAh g–1 at 1000 mA g–1 after 200 cycles.

Journal ArticleDOI
TL;DR: In this paper, the benefits, challenges, and prospects of biomass-based chemical looping technologies in various configurations have been discussed in-depth to provide important insight into the development of innovative BECCS technologies based on chemical loops.
Abstract: Biomass is a promising renewable energy resource despite its low energy density, high moisture content and complex ash components The use of biomass in energy production is considered to be approximately carbon neutral, and if it is combined with carbon capture technology, the overall energy conversion may even be negative in terms of net CO2 emission, which is known as BECCS (bioenergy with carbon capture and storage) The initial development of BECCS technologies often proposes the installation of a CO2 capture unit downstream of the conventional thermochemical conversion processes, which comprise combustion, pyrolysis or gasification Although these approaches would benefit from the adaptation of already well developed energy conversion processes and CO2 capture technologies, they are limited in terms of materials and energy integration as well as systems engineering, which could lead to truly disruptive technologies for BECCS Recently, a new generation of transformative energy conversion technologies including chemical looping have been developed In particular, chemical looping employs solid looping materials and it uniquely allows inherent capture of CO2 during the conversion of fuels In this review, the benefits, challenges, and prospects of biomass-based chemical looping technologies in various configurations have been discussed in-depth to provide important insight into the development of innovative BECCS technologies based on chemical looping

Journal ArticleDOI
TL;DR: This work reports the first single-atom bifunctional eletrocatalyst, namely, isolated nickel atom supported on β12 boron monolayer (Ni1/β12-BM), to achieve overall water splitting, and exhibits remarkable electrocatalytic performance.
Abstract: Nanosheet supported single-atom catalysts (SACs) can make full use of metal atoms and yet entail high selectivity and activity, and bifunctional catalysts can enable higher performance while lowering the cost than two separate unifunctional catalysts. Supported single-atom bifunctional catalysts are therefore of great economic interest and scientific importance. Here, on the basis of first-principles computations, we report a design of the first single-atom bifunctional eletrocatalyst, namely, isolated nickel atom supported on β12 boron monolayer (Ni1/β12-BM), to achieve overall water splitting. This nanosheet supported SAC exhibits remarkable electrocatalytic performance with the computed overpotential for oxygen/hydrogen evolution reaction being just 0.40/0.06 V. The ab initio molecular dynamics simulation shows that the SAC can survive up to 800 K elevated temperature, while enacting a high energy barrier of 1.68 eV to prevent isolated Ni atoms from clustering. A viable experimental route for the synth...

Journal ArticleDOI
TL;DR: The direct growth of high-quality van der Waals epitaxial growth of large-scale WSe2/SnS2 vertical bilayer p–n junctions on SiO2/Si substrates is reported, with the lateral sizes reaching up to millimeter scale.
Abstract: High-quality two-dimensional atomic layered p–n heterostructures are essential for high-performance integrated optoelectronics. The studies to date have been largely limited to exfoliated and restacked flakes, and the controlled growth of such heterostructures remains a significant challenge. Here we report the direct van der Waals epitaxial growth of large-scale WSe2/SnS2 vertical bilayer p–n junctions on SiO2/Si substrates, with the lateral sizes reaching up to millimeter scale. Multi-electrode field-effect transistors have been integrated on a single heterostructure bilayer. Electrical transport measurements indicate that the field-effect transistors of the junction show an ultra-low off-state leakage current of 10−14 A and a highest on–off ratio of up to 107. Optoelectronic characterizations show prominent photoresponse, with a fast response time of 500 μs, faster than all the directly grown vertical 2D heterostructures. The direct growth of high-quality van der Waals junctions marks an important step toward high-performance integrated optoelectronic devices and systems. Growth of large area and defect-free two-dimensional semiconductor layers for high-performance p–n junction applications has been a great challenge. Yang et al. prepare millimeter-scaled WSe2/SnS2 vertical heterojunctions by two-step van der Waals epitaxy, which show excellent optoelectronic properties.

Journal ArticleDOI
TL;DR: This paper considers the trajectory tracking of a marine surface vessel in the presence of output constraints and uncertainties, and an asymmetric barrier Lyapunov function is employed to cope with the output constraints.
Abstract: In this paper, we consider the trajectory tracking of a marine surface vessel in the presence of output constraints and uncertainties. An asymmetric barrier Lyapunov function is employed to cope with the output constraints. To handle the system uncertainties, we apply adaptive neural networks to approximate the unknown model parameters of a vessel. Both full state feedback control and output feedback control are proposed in this paper. The state feedback control law is designed by using the Moore–Penrose pseudoinverse in case that all states are known, and the output feedback control is designed using a high-gain observer. Under the proposed method the controller is able to achieve the constrained output. Meanwhile, the signals of the closed loop system are semiglobally uniformly bounded. Finally, numerical simulations are carried out to verify the feasibility of the proposed controller.

Journal ArticleDOI
Wei Gu1, Jun Wang1, Shuai Lu1, Zhao Luo1, Chenyu Wu1 
TL;DR: In this paper, an optimal operation model for an integrated energy system (IES) combining the thermal inertia of a district heating network (DHN) and buildings to enhance the absorption of wind power is proposed.

Journal ArticleDOI
TL;DR: The developed field modulation theory not only unifies the principle analysis of a large variety of electrical machines, including conventional dc machine, induction machine, and synchronous machine which are just special cases of the general field modulated machines, thus eliminating the problem of the machine theory fragmentation, but also provides a powerful guidance for inventing new machine topologies.
Abstract: This paper proposes a general field modulation theory for electrical machines by introducing magnetomotive force modulation operator to characterize the influence of short-circuited coil, variable reluctance, and flux guide on the primitive magnetizing magnetomotive force distribution established by field winding function multiplied by field current along the airgap peripheral. Magnetically anisotropic stator and rotor behave like modulators to produce a spectrum of field harmonics and the armature winding plays the role of a spatial filter to extract effective field harmonics to contribute the corresponding flux linkage and induce the electromotive force. The developed field modulation theory not only unifies the principle analysis of a large variety of electrical machines, including conventional dc machine, induction machine, and synchronous machine which are just special cases of the general field modulated machines, thus eliminating the problem of the machine theory fragmentation, but also provides a powerful guidance for inventing new machine topologies.