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Journal of Energy Chemistry 2022年第5期31卷 603-611页

作者： Zhenchuan tian Dukjoon Kim School of Chemical Engineering Sungkyunkwan UniversitySuwon 16419Republic of Korea

Poly(vinyl alcohol)/poly(ethylene glycol)(PVA/PEG) semi-interpenetrating networks(s-IPN) were synthesized for the application of solid electrolyte membranes of lithium metal batteries. Thermal, mechanical and dimensional stability, lithium-ion conductivity, interfacial compatibility, and cell performance were evaluated to assure their application. As this s-IPN structure suppressed the crystallinity by formation of network structure, both the lithium-ion conductivity and mechanical strength were simultaneously enhanced. The PVA/PEG-3s-IPN showed the highest lithium-ion conductivity of 3.26 × 10^(-4)S cm^(-1)in a wide electrochemical window(5.8 V vs. Li/Li^(+)), maintaining the robust solid-state with the tensile strength beyond 16.2 MPa at room temperature. The synthesized solid electrolyte membranes exhibited quite high specific capacity over 122 m Ah g^(-1)at 0.1 C from Li|PVA/PEG-3s-IPN|LiFePO_(4) cell and the long-term stable lithium stripping/plating performance for 1000 cycles from Li symmetric cell.

关键词： Solid polymer electrolyte Lithium battery Semi-IPN Lithium-ion conductivity

Learning a discriminative high-fidelity dictionary for single channel source separation

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Journal of Systems Engineering and Electronics 2021年第5期32卷 1097-1110页

作者： tian Yuanrong WANG Xing School of Electronic Countermeasure National University of Defense TechnologyHefei 230037China Institute of Aeronautics Engineering Air Force Engineering UniversityXi’an 710038China

Sparse-representation-based single-channel source separation,which aims to recover each source’s signal using its corresponding sub-dictionary,has attracted many scholars’*** basic premise of this model is that each sub-dictionary possesses discriminative information about its corresponding source,and this information can be used to recover almost every sample from that ***,in a more general sense,the samples from a source are composed not only of discriminative information but also common information shared with other *** paper proposes learning a discriminative high-fidelity dictionary to improve the separation *** innovations are ***,an extra sub-dictionary was combined into a conventional union dictionary to ensure that the source-specific sub-dictionaries can capture only the purely discriminative information for their corresponding sources because the common information is collected in the additional ***,a task-driven learning algorithm is designed to optimize the new union dictionary and a set of weights that indicate how much of the common information should be allocated to each ***,a source separation scheme based on the learned dictionary is *** results on a human speech dataset yield evidence that our algorithm can achieve better separation performance than either state-of-the-art or traditional algorithms.

关键词： single channel source separation sparse representation dictionary learning discrimination high-fidelity

Improving meta-learning model via meta-contrastive loss

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Frontiers of Computer Science 2022年第5期16卷 107-113页

作者： Pinzhuo tian Yang GAO Department of Computer Science and Technology Nanjing UniversityJiangsu 210023China

Recently,addressing the few-shot learning issue with meta-learning framework achieves great *** we know,regularization is a powerful technique and widely used to improve machine learning ***,rare research focuses on designing appropriate meta-regularizations to further improve the generalization of meta-learning models in few-shot *** this paper,we propose a novel metacontrastive loss that can be regarded as a regularization to fill this *** motivation of our method depends on the thought that the limited data in few-shot learning is just a small part of data sampled from the whole data distribution,and could lead to various bias representations of the whole data because of the different sampling ***,the models trained by a few training data(support set)and test data(query set)might misalign in the model space,making the model learned on the support set can not generalize well on the query *** proposed meta-contrastive loss is designed to align the models of support and query sets to overcome this *** performance of the meta-learning model in few-shot learning can be *** experiments demonstrate that our method can improve the performance of different gradientbased meta-learning models in various learning problems,e.g.,few-shot regression and classification.

关键词： meta-learning few-shot learning metaregularization deep learning

Transformation between polar and rectangular coordinates of stiffness and dampness parameters in hydrodynamic journal bearings

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Friction 2021年第1期9卷 201-206页

作者： Zhuxin tian Yu HUANG School of Mechanical Engineering Hubei University of Arts and ScienceXiangyang 441053China State Key Lab of Digital Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The stiffness and dampness parameters of journal bearings are required in rectangular coordinates for analyzing the stability boundary and threshold speed of oil film *** solving the Reynolds equation,the oil film force is always obtained in polar coordinates;thus,the stiffness and dampness parameters can be easily obtained in polar ***,the transformation between the polar and rectangular coordinates of journal bearing stiffness and dampness parameters is discussed in this study.

关键词： coordinate transformation stiffness parameters dampness parameters hydrodynamic journal bearings

Modeling the Wettability of Microstructured Hydrophobic Surface Using Multiple-relaxation-time Lattice Boltzmann Method

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Journal of Bionic Engineering 2022年第5期19卷 1460-1471页

作者： Lei tian Liuchao Qiu College of Water Resources and Civil Engineering China Agricultural UniversityBeijing 100083China

Wetting properties are significant for a hydrophobic surface and normally characterized by the equilibrium contact *** this manuscript,a mesoscopic method based on multiphase multiple-relaxation-time Lattice Boltzmann method has been presented and applied to simulate the contact angle at three-phase interfaces of a solid surface with micro-pillar *** influence of different parameters including pillar height,pillar width,inter-pillar spacing,intrinsic contact angle and the volume of the liquid drop on the equilibrium contact angle has been comprehensively *** effect of geometry parameters of the micro-pillar structure on the wetting transition from Cassie–Baxter state to Wenzel state has also been *** results indicate that when the inter-pillar spacing is less than a certain value or the pillar height is greater than a certain value,the contact form between the droplet and the surface satisfies the Cassie–Baxter *** the contact form satisfies the Cassie–Baxter state,the contact angle gradually increases with the increase of the inter-pillar spacing;the contact angle does not change significantly with the pillar height;the contact angle gradually decreases and approaches the intrinsic contact angle with the pillar width ***,the contact angle increases with the increase of the intrinsic contact angle,and the contact angle is not sensitive to the change of droplet volume when the droplet volume is between 0.5 and10μl.

关键词： Bioinspired hydrophobic surface Wettability Cassie-Baxter state Wenzel state Lattice Boltzmann method Mesoscale simulation

Simulation of Cement Hydration and Porous Structures by the Hydration-Pixel Probability Model

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Journal of Wuhan University of Technology(Materials Science) 2023年第5期38卷 1044-1055页

作者： tian Cong WEI Xiaosheng School of Civil Engineering Architecture&The EnvironmentHubei University of TechnologyWuhan 430072China School of Civil and Hydraulic Engineering Huazhong University of Science and TechnologyWuhan 430072China

This research proposes a new pixel-based model called the hydration-pixel probability model which aims to simplify cement hydration as a probability *** hydration capacity of cement,the solution within pores,and the difiusion of solid particles are represented by three probability functions derived from experimental data obtained through electrical resistivity and hydration heat *** principle of the model is relatively simple,and the parameters have clear physical *** this research,the porous structures of difierent cement pastes with w/c ratios of 0.3,0.4,and 0.5 are *** results indicate that the porosity of the cement paste decreases during the first few hours,followed by a rapid decline,and eventually reaches a steady *** porosity of the paste decreases as w/c ratio decreases,and the rate of decrease is more rapid in the early *** to the porosity curves,the average degree of hydration and depth of hydration can be *** simulation results show that the hydration degree of paste composed of irregular particles is higher than that of the paste composed of round *** trend in the development of the average hydration depth is similar to that of the average hydration *** analyzing the average growth rate of the hydration depth,it is observed that there are two peaks in the curves,which correspond to the three characteristic points in the electrical resistivity test.

关键词： cement hydration model porosity hydration degree simulation

Deep belief network-hidden Markov model based nonlinear equalizer for VCSEL based optical interconnect

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Science China(Information Sciences) 2020年第6期63卷 155-163页

作者： Fukui tian Chuanchuan YANG State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University

The data center has developed rapidly over the past few years, leading to the demand for high speed data transmission. Vertical cavity surface emitting lasers(VCSELs) based optical interconnect is evolving to 100 Gb/s and beyond, which makes nonlinear distortions difficult to be compensated or equalized by conventional equalizers. Moreover, the challenge becomes very complicated for conventional equalizers because of the presence of inter-symbol interference(ISI) together with the nonlinear distortions. So many neural network based DSP algorithms such as artificial neural network(ANN) have been proposed to mitigate the distortions. However, ANN has the limitations that sample's relevant information is not considered,leading to degradation in ANN's performance and high computational complexity. In this paper, in order to maintain an excellent capability of mitigating nonlinear distortions like other neural network based equalizers while considering the sample's relevant information to reduce the computational complexity, we propose a deep belief network-hidden Markov model(DBN-HMM) based nonlinear equalizer which is tested in a PAM-4 modulated VCSEL and multimode fiber(MMF) optical interconnect link experimentally. The BER performance can be greatly improved compared with conventional DSP algorithms. In addition, the computational complexity of DBN-HMM based equalizer can be about 41% lower than that of ANN based method with a similar BER performance.

关键词： short-range optical interconnect vertical cavity surface emitting laser(VCSEL) nonlinear equalizer deep belief network(DBN) hidden Markov model(HMM)

Designing and optimizing a parallel neural network model for predicting the solubility of diosgenin in n-alkanols

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Chinese Journal of Chemical Engineering 2021年第1期34卷 288-294页

作者： Huichao Lv Dayong tian School of Chemical&Environmental Engineering Anyang Institute of TechnologyAnyang 455000China

Accurate estimation of the solubility of a chemical compound is an important issue for many industrial proce *** overcome the defects of some thermodynamic models and simple correlations,a parallel neural network(PNN) model was conceived and optimized to predict the solubility of diosgenin in seven n-alkanols(C_(1)-C_(7)).The linear regression analysis of the parity plots indicates that the PNN model can give more accurate descriptions of the solubility of diosgenin than the ordinary neural network(ONN) *** comparison of the average root mean square deviation(RMSD) shows that the suggested model has a slight advantage over the thermodynamic NRTL model in terms of the calculating ***,the PNN model can reflect the effects of the temperature and the chain length of the alcohol solvent on the solution behavior of diosgenin correctly and can estimate its solubility in the n-alkanols with more carbon atoms.

关键词： Solubility Diosgenin Parallel neural network model NRTL model

Stabilization of Continuous-Time Systems Against Stochastic Network Uncertainties:Fundamental Variance Bounds

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Journal of Systems Science & Complexity 2021年第5期34卷 1858-1878页

作者： QI tian CHEN Jie School of Automation Science and Engineering Key Laboratory of Autonomous Systems and Networked ControlSouth China University of TechnologyGuangzhou 510640China Department of Electrical Engineering City University of Hong KongHong KongChina

This paper studies the stabilizability and stabilization of continuous-time systems in the presence of stochastic multiplicative *** authors consider multi-input,multi-output(MIMO)linear time-invariant systems subject to multiple static,structured stochastic uncertainties,and seek to derive fundamental conditions to ensure that a system can be stabilized under a mean-square *** the stochastic control framework,this problem can be considered as one of optimal control under state-or input-dependent random noises,while in the networked control setting,a problem of networked feedback stabilization over lossy communication *** authors adopt a mean-square small gain analysis approach,and obtain necessary and sufficient conditions for a system to be meansquare stabilizable via output *** single-input,single-output(SISO)systems,the condition provides an analytical bound,demonstrating explicitly how plant unstable poles,nonminimum phase zeros,and time delay may impose a limit on the uncertainty variance required for mean-square *** MIMO minimum phase systems with possible delays,the condition amounts to solving a generalized eigenvalue problem,readily solvable using linear matrix inequality optimization techniques.

关键词： Mean-square small gain theorem multiplicative stochastic uncertainty networked control

Corrections of Original CFPREV Control in LCC-HVDC Links and Analysis of Its Inherent Plateau Effect

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CSEE Journal of Power and Energy Systems 2022年第1期8卷 10-16页

作者： Dachuan tian Xiaofu Xiong College of Automation Chongqing University of Posts and TelecommunicationsChongqing 400065China School of Electrical Engineering Chongqing UniversityChongqing 400044China

The most effective approach to suppressing the first commutation failure(CF)of the LCC-HVDC link at fault inception is to advance firings of the inverter,and the commutation failure prevention(CFPREV)control is the most commonly used method in practical ***,it is discovered in this study that there exist a few serious defects in its original scheme,and thus targeted vital corrections were ***,an interesting phenomenon termed the plateau effect,which states that an excessive advancement of firings will contrarily and inevitably lead to more commutation failures,is also revealed and *** turns out that the inherent commutation dents of the Graetz bridge should be primarily responsible,which bridges the knowledge gap and further enhances the cognition of the limitation of CFPREV control,and it may also be conducive to the design of related control *** results then validate the necessity of these presented corrections and confirm the existence of the plateau effect.

关键词： Commutation failure CFPREV LCC-HVDC transmission plateau effect