Journals
2018 EN
Rensheng Song · Bo Wang · Ying Xie
+5 more
In this study, a non-lithiophilic nickel foam (NF) was transformed into a 3D lithiophilic N-doped graphene/nickel foam (NGNF) scaffold by a simple hydrothermal method. This scaffold can increase the area for Li deposition, improve the poor lithiophilicity of NF, and decrease the overpotential for Li deposition, leading to uniform Li plating/stripping. Thus, the average coulombic efficiency for Li deposition on the NGNF electrode can remain as high as 98.3% over 200 cycles and 98.0% over 100 cycles at current densities of 2 mA cm−2 and 4 mA cm−2, respectively. Even when the Li deposition capacity is increased to as high as 10 mA h cm−2, the cells with NGNF electrodes still exhibit stable cycling performance with a high coulombic efficiency of 98.9% after 84 cycles. Density functional theory (DFT) calculations were performed to achieve a deeper understanding of the interaction between Li atoms and the designed scaffold. In addition, the potential application of the scaffold is further demonstrated by the superior electrochemical performance of an assembled LiFePO4/Li-NGNF full cell under room-temperature and low-temperature conditions.
Royal Society of Chemistry
Journals
2018 EN
Zheng Wang · Lu Wen · Yanna Dou
+1 more
To investigate whether the human anti-thrombospondin type 1 domain-containing 7A (THSD7A) antibody-induced membranous nephropathy (MN) is mediated by activating lectin complement pathway. Automatic biochemical apparatus was used to assess renal function of mice. The serum levels of anti-THSD7A antibodies and complement were tested by using ELISA. The expression level of THSD7A and mannose-binding lectin (MBL) in clinical tissue, and the histological features of MN in mice were examined by immunochemical methods. We found that THSD7A, MBL, and complement expression level from patients with circulating anti-THSD7A antibodies were significantly higher than that in normal group. Furthermore, difference of renal function in anti-THSD7A antibody-containing serum treatment groups and control groups was significant. Meanwhile, human anti-THSD7A autoantibodies activated the complement system and induced the histological features of MN in mice. In conclusion, human anti-THSD7A antibodies induce MN through activating MBL lectin complement pathway in mice.
Journals
2018 EN
Li Yuenan · Wang Dongdong · Wang Jingru
Paralleling with the revolutionary development of the Internet, there has been increasing concern about the copyright infringement of digital media. A central problem in copyright protection is to accurately and efficiently identify the illegal copies of copyrighted contents. Perceptual hash function, which summarises the perceptual characteristics of digital media to a short digest, is a low‐cost solution to this problem. Owing to the easy‐to‐manipulate nature of digital media, a major challenge in designing perceptual hash function is to achieve the robustness against distortion. To tackle this problem, an associative memory‐based hash function is introduced. The proposed work repairs the distortions on local image structures via associative memory‐based de‐noising, in the hope of simulating the self‐correcting mechanism in human memory. The shape invariant descriptors of de‐noised structures are then encoded to binary bits. Experimental results confirm that the proposed work outperforms representative algorithms, and it can achieve an equal error rate of 3.30 × 10 − 3in content identification with only 80 bits.
The Institution of Engineering and Technology
Journals
2018 EN
Xu Bing · Dou Jie · Dou Lei
Due to its flexibility in calculating frequency spectrum, the chirp z‐transform (CZT) has been used in various applications where high‐frequency resolution is desirable, e.g. the acquisition of global positioning system (GPS) signals. However, the CZT is very time consuming when dealing with the very large size of input data. Thus, typically, only 1 ms data is used for GPS signal acquisition. In this Letter, the authors improve the acquisition precision and sensitivity of the CZT‐based acquisition by extending coherent integration time. To reduce computation load, they introduce a down‐sampling operation to the extended data without degrading acquisition performance. Results show that the CZT‐based acquisition with a coherent integration time of 10 ms obtains a frequency error of 5.9 Hz for the carrier‐to‐noise ratio (CNR) of 25 dB‐Hz and can acquire signals with a CNR down to 22 dB‐Hz.
The Institution of Engineering and Technology
Journals
2018 EN
Li Suoping · Sun Hongchun · Dou Zufang
+1 more
The transmission capacity (TC) of the wireless ad‐hoc network is one of the key properties to ensure the quality of network service. The main goal of this study is to explore the mobility of the network to establish a node mobile model with a saturated state and determine the TC and delay for the network based on the bidirectional full‐duplex (BFD) system. Considering the outage probability, packet arrival rate, and failure probability of packet attempting transmission, the node mobility models are established based on the node mobility and network self‐organization. In analysis, this study determines the mobile state, static state, communication state, and outage stat by defining the mobile rule and range of nodes, then the steady‐state probability of each state is obtained by calculating the state transition matrix. After optimising the existing saturated Markov model, the authors determine the network delay and TC based on the mobile nodes, contention window size, maximum number of given packet attempting retransmission, back‐off time and signal‐interference ratio (SIR) etc. The theoretical analysis and numerical simulation show that the TC of the bidirectional ad‐hoc network can be significantly improved by using space resources in two directions, and the introduction of the BFD system is indeed to reduce the network delay.
The Institution of Engineering and Technology
Journals
2018 EN
Dou Gaoqi · He Xianwen · Deng Ran
+2 more
In amplify‐and‐forward relay networks, accurate channel estimation of individual links is essential for coherent reception and optimal design. To acquire the channel state information of individual links, a novel in‐band superimposed training is proposed, where relay superimposes its own training sequence directly on top of the information‐bearing received data. As a result, the training sequences from the source and relay nodes are independent of each other, thus making it more flexible and robust in relay‐training design. However, the proposed training scheme induces extra data interference that degrades the estimation performance. The authors first adopted the detected symbols to mitigate the data‐induced interference during channel estimation. However, the estimation performance is degraded by the symbol detection error and relay propagated noise. To resolve this problem, the interference nulling at the relay is proposed, where some special frequency components of the received data are nulled prior to training superimposition. As a result, both the data‐induced interference and relay propagated noise are totally removed during channel estimation. Simulation results are provided to assess the performance of the proposed schemes.
The Institution of Engineering and Technology
Journals
2018 EN
Dou Liqian · Su Peihua · Zong Qun
+1 more
For an air‐breathing hypersonic vehicle with a variable geometry inlet (AHV‐VGI), a movable translating cowl is used to track the shock on lip conditions to capture enough air mass flow, which can extend the velocity range and be favourable to the acceleration and manoeuvring flight. The authors firstly establish longitudinal dynamics for AHV‐VGI, and consider the lumped disturbances which include the unknown external disturbance, the parameter uncertainties and the uncertainty parts introduced by translating cowl. Then, the dynamic surface control strategy based on a fuzzy disturbance observer (FDO) is proposed for AHV‐VGI control. The control process for AHV‐VGI is divided into two subsystems. For each subsystem, a sliding mode controller is designed, and FDOs are adopted to compensate the lumped disturbances, which can render the disturbance estimate errors convergent. Numerical simulations are presented to illustrate the effectiveness of the proposed method and the advantages of translating cowl.
The Institution of Engineering and Technology
Journals
2018 EN
Ran Chenjian · Sun Shuli · Dou Yinfeng
For multisensor descriptor systems with uncertain noise variances, the weighted measurement fusion (WMF) reduced‐order robust estimators are presented. The multisensor descriptor systems with known upper bounds of uncertain noise variances are defined as the worst‐case conservative multisensor descriptor systems. For the worst‐case conservative multisensor descriptor systems, the WMF reduced‐order conservative Kalman estimators, including filter, predictor and smoother, are obtained, by applying the WMF method and the singular value decomposition method. However, the measurements of the conservative multisensor descriptor systems are unavailable. Replacing these unavailable conservative measurements by the actual and available measurements yields the actual WMF reduced‐order robust estimators. Their robustness is proven by the dynamic error variance system method, i.e. the actual estimation error variances are not greater than those of conservative systems. Two simulation examples of four‐sensor descriptor systems show the effectiveness of the presented algorithms.
The Institution of Engineering and Technology
Journals
2018 EN
Dou Jun · Niu Dongmei · Feng Zhiquan
+1 more
Point set registration is a fundamental problem in many domains of computer vision. In previous work on the registration, the point sets are often represented using Gaussian mixture models and the registration process is represented as a form of a probabilistic solution. For non‐rigid point set registration, however, the asymmetric Gaussian (AG) model can capture spatially asymmetric distributions compared with symmetric Gaussian, and the structural feature of the point sets reserve relatively complete and has important significance in registration. In this work, the authors designed a new shape context (SC) descriptor which combines the local and global structures of the point set. Meanwhile, they proposed a non‐rigid point set registration algorithm which formulates a registration process as the mixture probability density estimation of the AG mixture model, and the method introduce the structural feature by the new SC. Extensive experiments show that the proposed algorithm has a clear improvement over the state‐of‐the‐art methods.
The Institution of Engineering and Technology
Journals
2018 EN
Wang Qing · Chen Hao · Dou Yuyu
+1 more
In this study, an improved phase current control scheme (CCS) for switched reluctance generator is developed and evaluated. The objective of proposed CCS is to find the most efficient operating point according to output power command directly and shorten the online tuning process. The CCS is augmented with an online phase current distributing block (OCDB) and a dynamic firing angle regulator (DFAR). In OCDB, phase current is distributed online to minimise copper loss by maximising the average‐torque–ampere ratio. In DFAR, firing angles are processed according to actual phase current and current command. Improvements in current responses by augmenting DFAR are verified by simulations and experiments. In the end, the proposed CCS is employed in an output power controller for practical applications. Experimental results show that the proposed CCS has good dynamic response and finds the most efficient operating point directly.
The Institution of Engineering and Technology