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AN EME BliND SOURCE SEPARATION ALGORITHM BASED ON GENERAliZED EXPONENTIAL FUNCTION

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Journal of Electronics(China) 2008年第2期25卷 262-267页

作者： miao hao li Xiaodong Tian Jing Institute of Acoustics Chinese Academy of Sciences Beijing 100190 China

This letter investigates an improved blind source separation algorithm based on Maximum Entropy （ME） criteria. The original ME algorithm chooses the fixed exponential or sigmoid ftmction as the nonlinear mapping function which can not match the original signal very well. A parameter estimation method is employed in this letter to approach the probability of density function of any signal with parameter-steered generalized exponential function. An improved learning rule and a natural gradient update formula of unmixing matrix are also presented. The algorithm of this letter can separate the mixture of super-Gaussian signals and also the mixture of sub-Gaussian signals. The simulation experiment demonstrates the efficiency of the algorithm.

关键词： Blind source separation Maximum Entropy (ME) Generalized exponential function

STDNet: A Spatio-Temporal Decomposition Neural Network for Multivariate Time Series Forecasting

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Tsinghua Science and Technology 2024年第4期29卷 1232-1247页

作者： Zhuolun Jiang Zefei Ning hao miao li Wang College of Computer Science and Technology(College of Data Science) Taiyuan University of TechnologyJinzhong 030600China

Long-term multivariate time series forecasting is an important task in engineering applications. It helps grasp the future development trend of data in real-time, which is of great significance for a wide variety of fields. Due to the non-linear and unstable characteristics of multivariate time series, the existing methods encounter difficulties in analyzing complex high-dimensional data and capturing latent relationships between multivariates in time series, thus affecting the performance of long-term prediction. In this paper, we propose a novel time series forecasting model based on multilayer perceptron that combines spatio-temporal decomposition and doubly residual stacking, namely Spatio-Temporal Decomposition Neural Network (STDNet). We decompose the originally complex and unstable time series into two parts, temporal term and spatial term. We design temporal module based on auto-correlation mechanism to discover temporal dependencies at the sub-series level, and spatial module based on convolutional neural network and self-attention mechanism to integrate multivariate information from two dimensions, global and local, respectively. Then we integrate the results obtained from the different modules to get the final forecast. Extensive experiments on four real-world datasets show that STDNet significantly outperforms other state-of-the-art methods, which provides an effective solution for long-term time series forecasting.

关键词： time series forecasting multivariate time series spatio-temporal decomposition

Electron engineering of nickel phosphide for Ni^(δ+) in electrochemical nitrate reduction to ammonia

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Nano Research 2024年第6期17卷 4864-4871页

作者： Jie Hu hao Huang miao Yu Shuang Wang Jinping li College of Environmental Science and Engineering Taiyuan University of TechnologyJinzhong 030600China School of Sustainable Energy Materials and Science Jinhua Advanced Research InstituteJinhua 321000China Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization Taiyuan University of TechnologyTaiyuan 030024China

The electrochemical reduction of nitrate to ammonia(ENRA)provides an efficient approach to remove nitrate pollution and achieve ammonia production ***,inspired by bio-enzyme in denitrifying bacteria,a carbon-coated nickel phosphide(NiPC)nanosheet derived from metal-organic frameworks(MOFs)is proposed as an efficient catalyst for *** electron engineering,controllable Ni^(δ+)in nickel phosphide is achieved by regulating the degree of phosphating,which enhances its activity for the hydrogenation of *** the result,Niδ+becomes one of dominating factors determining the efficiency of the ENRA reaction in nickel *** optimal NiPC catalyst exhibits impressive property toward ENRA:NH_(4)^(+)Faraday efficiency of 96.68%,NH4+selectivity of 99.04%,and nitrate conversion rate of 90.43%under low nitrate concentration(200 mg·L^(−1)).This work opens a new avenue for the design of next-generation catalysts through electron engineering for ENRA.

关键词： electron engineering transition metal phosphide nitrate reduction ammonia production metal-organic frameworks

Mitigating set-stuck failure in 3D phase change memory: substituting square pulses with surge pulses

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Science China(Information Sciences) 2024年第5期67卷 295-301页

作者： Ninghua li Wang CAI Jun XIANG hao TONG Weiming CHENG Xiangshui miao School of Integrated Circuits Huazhong University of Science and Technology Hubei Yangtze Memory Laboratories Hubei Institute of Measurement and Testing Technology

In the devices that integrate phase change memory(PCM) and ovonic threshold switching(OTS),the OTS threshold voltage often surpasses the RESET operation voltage of PCM. The conventional application of square pulses hinders the successful completion of the SET operation in these integrated devices. To address this challenge, a novel pulse called the surge pulse is introduced, which comprises a high amplitude pulse for OTS activation and a low amplitude pulse for PCM operation. By employing COMSOL simulation,the operational effectiveness of both square pulses and surge pulses is validated. Test results reveal that using a square pulse to operate the integrated device accelerates the occurrence of SET-stuck failure(SSF).In contrast, the surge pulse enables the integrated device to operate for at least 1000 cycles while preserving the essential cyclic characteristics. Additionally, an investigation into the overshoot component of the surge pulse is conducted, revealing that an increase in overshoot amplitude and pulse width also accelerates the emergence of SSF. By applying the theory of ion migration induced by the electric field, the root cause of SSF in integrated devices is explained, and the accuracy of the theory is validated through the application of a reverse pulse. In summary, this study elucidates the rationality of replacing the square pulse with a surge pulse, presenting a superior approach for operating PCM and OTS integrated devices.

关键词： surge pulse phase change memory (PCM) integration SET-stuck failure (SSF) square pulse

Constructing extrinsic oxygen vacancy on the surface of photocatalyst as CO_(2)and electrons reservoirs to improve photocatalytic CO_(2)reduction activity

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Journal of Environmental Sciences 2024年第6期140卷 37-45页

作者： Zaiyong Jiang hao li Zhimin Yuan Zheng Wang Maohong Fan Wenkang miao Hong He State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China School of Chemistry&Chemical Engineering and Environmental Engineering Weifang UniversityWeifangShandong 261061China Departments of Chemical and Petroleum Engineering University of WyomingLaramieWY 82071USA Materials Genome Institute Shanghai UniversityShanghai 200444China

Constructing own oxygen vacancies in the photocatalysts is a very promising method to improve their photocatalytic CO_(2)reduction ***,some catalysts have excellent stabilities,making it difficult for them to construct their own oxygen *** simplify the above difficulty of stable photocatalysts,constructing extrinsic oxygen vacancies on their surface as a novel idea is ***,a stable TiO_(2)nanosheet is chosen as a research object,we uniformly deposited BiOCl quantum dots on their surface via a simple adsorption-deposition *** is found that BiOCl quantum dots are able to simultaneously self-transform into defective BiOCl with many oxygen vacancies when the photocatalyst is performed photocatalytic CO_(2)*** extrinsic oxygen vacancies can act as“CO_(2)and photo-generated electrons reservoirs”to improve CO_(2)capture and accelerate the separation of photogenerated electrons and *** the above reasons,the modified TiO_(2)showed obvious enhancement of photocatalytic CO_(2)reduction compared to pristine TiO_(2)and *** work may open a new avenue to broaden the use of oxygen vacancies in the process of photocatalytic CO_(2)reduction.

关键词： Oxygen vacancy BiOCl Photocatalyst CO_(2)reduction TiO_(2)

Performance evaluation of the effect of humic acid on Anammox granular sludge:Apparent morphology,nitrogen removal and microbial community

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Journal of Environmental Sciences 2024年第10期144卷 148-158页

作者： Wenhui Huang Peiling Xu Xiang li Yong Huang hao Sun Wei li Mao Zhang miao Shi Yan Yuan School of Environmental Science and Engineering Suzhou University of Science and TechnologySuzhou 215009China Suzhou Hongyu Environmental Technology Company limited by Shares Suzhou 215011China Suzhou Tianjun Environmental Technology limited Company Suzhou 215011China Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment Suzhou University of Science and TechnologySuzhou 215009China

Humic acid(HA)is a typical refractory organicmatter,so it is of great significance to investigate its effect on the performance of Anammox granular *** the dosage ofHA≤50 mg/L,HA promotes the total nitrogen removal rate(NRR)to 1.45 kg/(m^(3)·day).When HA was between 50 and 100 mg/L,the NRR of Anammox was *** this time,the adsorption of HA causes the sludge to gradually turn fromred to brown,but the activities of heme and enzymes showed that its capacitywas not *** HA levels reached 250 mg/L,the NRR dropped to 0.11 kg/(m3·day).Moderate HA levels promoted the release of extracellular polymeric substance(EPS),but excessive HA levels lead to a decrease in EPS *** inhibited Anammox activity,which indirectly hindered the transmission of substrate and accumulated substrate *** HA promoted the increase of heterotrophicmicrobial abundance in Anammox system,the microbial diversity decreased *** the increase of HA concentration,the abundance of Candidatus_Brocadia,the main functional microorganism of Anammox system,decreased gradually,while the abundance of Candidatus_Kuenenia increased gradually.

关键词： Anammox Landfill leachate Humic acid Heme Microbial community Enzyme activity

A Fault Detection Method for Electric Vehicle Battery System Based on Bayesian Optimization SVDD Considering a Few Faulty Samples

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Energy Engineering 2024年第9期121卷 2543-2568页

作者： miao li Fanyong Cheng Jiong Yang Maxwell Mensah Duodu hao Tu School of Electronics and Electrical Engineering Anhui Polytechnic UniversityWuhu241000China

Accurate and reliable fault detection is essential for the safe operation of electric *** vector data description(SVDD)has been widely used in the field of fault ***,constructing the hypersphere boundary only describes the distribution of unlabeled samples,while the distribution of faulty samples cannot be effectively described and easilymisses detecting faulty data due to the imbalance of sample ***,selecting parameters is critical to the detection performance,and empirical parameterization is generally timeconsuming and laborious and may not result in finding the optimal ***,this paper proposes a semi-supervised data-driven method based on which the SVDD algorithm is improved and achieves excellent fault detection *** incorporating faulty samples into the underlying SVDD model,training deals better with the problem of missing detection of faulty samples caused by the imbalance in the distribution of abnormal samples,and the hypersphere boundary ismodified to classify the samplesmore *** Bayesian Optimization NSVDD(BO-NSVDD)model was constructed to quickly and accurately optimize hyperparameter *** the experiments,electric vehicle operation data with four common fault types are used to evaluate the performance with other five models,and the results show that the BO-NSVDD model presents superior detection performance for each type of fault data,especially in the imperceptible early and minor faults,which has seen very obvious ***,the strong robustness of the proposed method is verified by adding different intensities of noise in the dataset.

关键词： Fault detection vehicle battery system lithium batteries fault samples

Structural and Luminescent Properties of Mg_(0.25-x)Al_(2.57)O_(3.79)N_(0.21):xMn^(2+)Green-Emitting Transparent Ceramic Phosphor

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Journal of Wuhan University of Technology(Materials Science) 2024年第3期39卷 533-540页

作者：郝留成 miao Xiaojun li Kai ZHONG Jianying 涂兵田 YANG Zhangfu 王皓 Pinggao Group Co. LtdPingdingshan 467001China State Key Lab of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 430070China School of Materials Science and Engineering Anhui University of Science and TechnologyHuainan 232001China

A series of spinel-type Mg_(0.25-x)Al_(2.57)O_(3.79)N_(0.21):xMn^(2+)(MgAlON:xMn^(2+))phosphors were synthesized by the solid-state reaction *** transparent ceramic phosphors were fabricated by pressureless sintering followed by hot-isostatic pressing(HIP).The crystal structure,luminescence and mechanical properties of the samples were systematically *** transparent ceramic phosphors with tetrahedrally coordinated Mn^(2+)show strong green emission centered around 515 nm under blue light *** the Mn^(2+)concentration increases,the crystal lattice expands slightly,resulting in a variation of crystal field and a slight red-shift of green emission *** weak absorption peaks in the transmittance spectra originate from the spin-forbidden ^(4)T_(1)(^(4)G)→^(6)A_(1) transition of Mn^(2+).The decay time was found to decrease from 5.66 to 5.16 ms with the Mn^(2+)*** present study contributes to the systematic understanding of crystal structure and properties of MgAlON:xMn^(2+)green-emitting transparent ceramic phosphor which has a potential application in high-power light-emitting diodes.

关键词： transparent ceramic phosphor green emission MgAlON photoluminescence

A statistical damage-based constitutive model for shearing of rock joints in brittle drop mode

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International Journal of Mining Science and Technology 2024年第8期34卷 1041-1058页

作者： Xinrong liu Peiyao li Xueyan Guo Xinyang Luo Xiaohan Zhou Luli miao Fuchuan Zhou hao Wang School of Civil Engineering Chongqing UniversityChongqing 400045China National Joint Engineering Research Center of Geohazards Prevention in The Reservoir Areas(Chongqing) Chongqing 400045China Key Laboratory of New Technology for Construction of Cities in Mountain Area(Chongqing University) Ministry of EducationChongqing 400045China Chongqing Vocational Institute of Engineering Chongqing 402260China

Some rock joints exhibit significant brittleness,characterized by a sharp decrease in shear stress upon reaching the peak ***,existing models often fail to accurately represent this behavior and are encumbered by numerous parameters lacking clear mechanical *** study presents a new statistical damage constitutive model rooted in both damage mechanics and statistics,containing only three model *** proposed model encompasses all stages of joint shearing,including the compaction stage,linear stage,plastic yielding stage,drop stage,strain softening stage,and residual strength *** derive the analytical expression of the constitutive model,three boundary conditions are *** data from both natural and artificial rock joints is utilized to validate the model,resulting in average absolute relative errors ranging from 3%to 8%.Moreover,a comparative analysis with established models illustrates that the proposed model captures stress drop and post-peak strain softening more effectively,with model parameters possessing clearer mechanical ***,parameter analysis is conducted to investigate the impacts of model parameters on the curves and unveil the relationship between these parameters and the mechanical properties of rock ***,the proposed model is straightforward in form,and all model parameters can be obtained from direct shear tests,thus facilitating the utilization in numerical simulations.

关键词： Rock joints Brittle rock Direct shear test Damage-based constitutive model Parameters analysis