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Pilot-scale experiments on multilevel contact oxidation treatment of poultry farm wastewater using saran lock carriers under different operation model

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Journal of Environmental Sciences 2019年第3期31卷 336-345页

作者： Tianlong Zheng Peng Li Xiaoyu Ma Xiaohong Sun Chuanfu Wu Qunhui Wang Ming Gao State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Department of Environmental Engineering University of Science and Technology Beijing Xinkai Water Environmental Investment Co.Ltd Beijing Agro-Biotechnology Research Center Beijing Academy of Agriculture and Forestry Sciences

A pilot-scale multilevel contact oxidation reactors system, coupled with saran lock carriers,was applied for the treatment of poultry farm wastewater. The removal efficiencies of CODcr, ammonia, and the total nitrogen as well as the elimination performance of CODcr and total nitrogen along the three-level contact oxidation tanks under six designed operational models were investigated. Based on the performance of the nitrogen removal of the saran lock carriers and the distribution of anoxic–aerobic interspace under the suitable operation model, the mechanism of nitrogen removal of the system was also explored. The results revealed that the intermittent aeration under parallel model is the most suitable operation model, while the removal efficiencies of CODcr, ammonia, and the total nitrogen were 86.86%, 84.04%, and 80.96%, respectively. The effluent concentration of CODcr,ammonia, and the total nitrogen were 55.6 mg/L, 8.3 mg/L, and 12.0 mg/L, which satisfy both the discharge standard of pollutants for livestock and poultry breeding industry(GB18596–2001) and the first grade of the integrated wastewater discharge standard(GB 8978–1996). Moreover, the mechanism for the nitrogen removal should be attributed to the plenty of anoxic–aerobic interspaces of the biofilm and the three-dimensional spiral structure of the saran lock carriers, where the oxygen-deficient distribution was suitable for the happening of the simultaneous nitrification and denitrification process. Therefore, the multilevel contact oxidation tanks system is an effective pathway for the treatment of the poultry farm wastewater on the strength of a suitable operation model and novel carriers.

关键词： multilevel contact oxidation tanks Nitrogen removal Mechanism Operation model Poultry farm wastewater Saran lock carriers

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multilevel Image Thresholding Using Tsallis Entropy and Cooperative Pigeon-inspired Optimization Bionic Algorithm

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Journal of Bionic Engineering 2019年第5期16卷 954-964页

作者： Yiin Wang Guangbin Zhang Xiaofeng Zhang School of Physics and Information Technology Shaanxi Normal UniversityXi'an 710119China

multilevel thresholding is a simple and effective method in numerous image segmentation *** this paper,we propose a new multilevel thresholding method that uses cooperative pigeon-inspired optimization algorithm with dynamic distance threshold(CPIOD)for boosting applicability and the practicality of the optimum thresholding ***,we employ the cooperative be havior in the map and compass operator of the pigeon-inspired optimization algorithm to overcome the"curse of dimensionality"and help the algorithm converge ***,a distance threshold is added to maintain the diversity of the pigeon population and increase the vitality to avoid local *** entropy is used as the objective function to evaluate the optimum thresholds for the considered gray scale *** benchmark images are applied to test the property and the stability of the proposed CPIOD algorithm and three other optimization algorithms in multilevel thresholding *** results of four optimization algorithms show that CPIOD algorithm can not only get higher quality segmentation results,but also has better stability.

关键词： bionic algorithm multilevel thresholding Tsallis entropy pigeon-inspired optimization image segmentation

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A Context Sensitive multilevel Thresholding Using Swarm Based Algorithms

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IEEE/CAA Journal of Automatica Sinica 2019年第6期6卷 1471-1486页

作者： Shreya Pare Anil Kumar Varun Bajaj Girish Kumar Singh PDPM Indian Institute of Information Technology Design and Manufacturing Jabalpur 482005MPIndia Institute of Technology Roorkee Uttarakhand 247667India

In this paper, a comprehensive energy function is used to formulate the three most popular objective functions:Kapur's, Otsu and Tsalli's functions for performing effective multilevel color image thresholding. These new energy based objective criterions are further combined with the proficient search capability of swarm based algorithms to improve the efficiency and robustness. The proposed multilevel thresholding approach accurately determines the optimal threshold values by using generated energy curve, and acutely distinguishes different objects within the multi-channel complex images. The performance evaluation indices and experiments on different test images illustrate that Kapur's entropy aided with differential evolution and bacterial foraging optimization algorithm generates the most accurate and visually pleasing segmented images.

关键词： Color image segmentation Kapur's entropy multilevel thresholding Otsu method swarm based optimization algorithms Tsalli's entropy

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PAM: an efficient power-aware multilevel cache policy to reduce energy consumption of storage systems

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Frontiers of Computer Science 2019年第4期13卷 850-863页

作者： Xiaodong MENG Chentao WU Minyi GUO Long ZHENG Jingyu ZHANG Shanghai Key Laboratory of Scalable Computing and Systems Department of Computer Science & Engineering Shanghai Jiao Tong University Shanghai 200240 China

Energy consumption is one of the most significant aspects of large-scale storage systems where multilevel caches are widely used. In a typical hierarchical storage structure, upper-level storage serves as a cache for the lower level, forming a distributed multilevel cache system. In the past two decades, several classic LRU-based multilevel cache policies have been proposed to improve the overall I/O performance of storage systems. However, few power-aware multilevel cache policies focus on the storage devices in the bottom level, which consume more than 27% of the energy of the whole system [1]. To address this problem, we propose a novel power-aware multilevel cache (PAM) policy that can reduce the energy consumption of high-performance and I/O bandwidth storage devices. In our PAM policy, an appropriate number of cold dirty blocks in the upper level cache are identified and selected to flush directly to the storage devices, providing high probability extension of the lifetime of disks in standby mode. To demonstrate the effectiveness of our proposed policy, we conduct several simulations with real-world traces. Compared to existing popular cache schemes such as PA? LRU, PB-LRU, and Demote, PAM reduces power consumption by up to 15% under different I/O workloads, and improves energy efficiency by up to 50.5%.

关键词： storage system multilevel cache energy consumption I/O performance hint

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Reliability evaluation of modular multilevel converter based on Markov model

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Journal of Modern Power Systems and Clean Energy 2019年第5期7卷 1355-1363页

作者： Liang ZHANG Dan ZHANG Ting HUA Jihong ZHU Gang CHEN Tongzhen WEI Ting YANG School of Power Electric Engineering Nanjing Institute of TechnologyNanjing 211167China State Key Laboratory of Intelligent Technology and Systems Tsinghua UniversityBeijing 100084China School of Electronic Information and Electrical Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Grid Jiangsu Electric Power Company Xuzhou Power Supply Company Xuzhou 221005China Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China

The modular multilevel converter(MMC)is now the most attractive topology for medium and high voltage power conversion applications with several advantages over the traditional voltage source converter(VSC).However,due to a large number of sub-modules(SMs)in the MMC,system reliability is a big challenge in its practical application,where each SM may be considered as a potential point of *** this paper,a reliability evaluation based on the Markov model is proposed for the *** failure rates of the power electronic devices and SMs are firstly ***,the Markov model and the state transition equation of the system are built in detail.A general reliability evaluation function is established,in which the mean time to failure and reliability evaluation of the MMC with redundant SMs are also ***,a practical direct current(DC)distribution example for reliability evaluation is analyzed,and the results verify that the reliability evaluation based on the Markov model could provide a useful reference for project design.

关键词： Modular multilevel converters Reliability evaluation Markov model

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"Chameleon-like" optical behavior of lanthanide-doped fluoride nanoplates for multilevel anti-counterfeiting applications

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Nano Research 2019年第6期12卷 1417-1422页

作者： Wenwu You Datao Tu Renfu Li Wei Zheng Xueyuan Chen CAS Key Laboratory of Design and Assembly of Functional Nanostructures and Fujian Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

Lanthanide-based luminescent anti-counterfeiting materials are widely used in various kinds of ***,the emission color of traditional lanthanide-based luminescent materials usually remains nearly unaltered upon different excitation lights,which may only work for single-level ***,the NaYbF4∶2%Er@NaYF4 core/shell nanoplates (NPs) with "chameleon-like" optical behavior are *** NPs display single-band red or green downshifting (DS) emission upon excitation at 377 or 490 nm,*** 980 nm excitation,the color of upconversion (UC) emission can be finely tuned from green to yellow,and to red with increasing the excitation power density from 0.1 to 4.0 W/cm^*** proposed materials readily integrate the advantages of excitation wavelength-dependent DS single-band emissions and sensitive excitation power-dependent UC multicolor emissions in one and the same material,which has never been reported ***,the proposed NPs exhibit excellent performance as security labels on trademark tag and security ink on painting,thus revealing the great potential of these lanthanide-doped fluoride NPs in multilevel anti-counterfeiting applications.

关键词： lanthanide-doped chameleon-like upconversion downshifting multilevel anti-counterfeiting

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A new multilevel voltage source inverter configuration with minimum number of circuit elements

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Journal of Central South University 2017年第4期24卷 912-920页

作者： Mohammad Reza Jannati Oskuee Masoumeh Karimi Yahya Naderi Sajad Najafi Ravadanegh Seyyed Hossein Hosseini Smart Distribution Grid Research Lab. Electrical Engineering Department Azarbaijan Shahid Madani University Tabriz Iran Faculty of Electrical and Computer Engineering University of Tabriz Tabriz Iran

An advanced configuration for multilevel voltage source converters is proposed. The proposed converter is able to apply asymmetrical DC sources. The configuration of the proposed inverter is well designed in order to provide the maximum number of voltage levels in output terminals using lower number of circuit devices. The authority of the proposed inverter versus the conventional H-bridge cascaded inverter and the most recently introduced ones, is verified with a provided comparison study. The proposed inverter is able to generate the desired voltage levels using a lower number of circuit devices including power semi-conductor switches, IGBTs, diodes, related gate driver circuits of switches and DC voltage sources. As a result, the total cost and installation area are considerably reduced and the control scheme gets simpler. To confirm the feasibility of the proposed multilevel structure, both the simulation and experimental results are provided and compared which shows good agreements.

关键词： multilevel voltage source inverter reduction of circuit components symmetric inverter asymmetric inverter

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Batch process monitoring based on multilevel ICA-PCA

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第8期9卷 1061-1069页

作者： Zhi-qiang GE Zhi-huan SONG State Key Lab of Industrial Control Technology Institute of Industrial Process Control Zhejiang University Hangzhou 310027 China

In this paper, we describe a new batch process monitoring method based on multilevel independent component analysis and principal component analysis (MLICA-PCA). Unlike the conventional multi-way principal component analysis (MPCA) method, MLICA-PCA provides a separated interpretation for multilevel batch process data. Batch process data are partitioned into two levels: the within-batch level and the between-batch level. In each level, the Gaussian and non-Gaussian components of process information can be separately extracted. I2, T2 and SPE statistics are individually built and monitored. The new method facilitates fault diagnosis. Since the two variation levels are decomposed, the variables responsible for faults in each level can be identified and interpreted more easily. A case study of the Dupont benchmark process showed that the proposed method was more efficient and interpretable in fault detection and diagnosis, compared to the alternative batch process monitoring method.

关键词： multilevel Independent component analysis (ICA) Principal component analysis (PCA) Batch process monitoring Non-Gaussian

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multilevel oblique corpectomies as an effective surgical option to treat cervical chordoma in a young girl

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World Journal of Clinical Cases 2014年第3期2卷 57-61页

作者： Roberto Delfini Daniele Marruzzo Roberto Tarantino Nicola Marotta Alessandro Landi Department of Neurology and Psychiatry Division of Neurosurgery University of Rome "Sapienza"

Chordomas are malignant tumors arising from notochordal remnants. They are the most frequent tumors of the spine after plasmacytomas. Only 6% of chordomas are localized to the cervical level. In young patients, chordomas are rare and unpredictable. Despite this, the treatment of choice remains the total resection, as much as possible, followed by proton beam radiation. This case was managed using a precarotid and retrocarotid approach at the same time. The tumor was completely resected with the edges free from disease. The cervical spine was stabilized with an anterior plating C2-C4. Eighteen months after surgery the patient is still free from illness. multilevel oblique corpectomies are an available and safe option for the treatment of upper cervical chordomas.

关键词： Cervical chordoma multilevel oblique corpectomy Surgery RXT Retrocarotid approach

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Isolated Bipolar Modular multilevel DC-DC Converter with Self-balancing Capability for Interconnection of MVDC and LVDC Grids

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CSEE Journal of Power and Energy Systems 2023年第1期9卷 365-379页

作者： Jinmu Lai Xin Yin Yaoqiang Wang Lin Jiang Zia Ullah Xianggen Yin School of Electrical and Information EngineeringZhengzhou UniversityZhengzhou 450001China Department of Electrical Engineering and ElectronicsUniversity of LiverpoolLiverpoolUK State Key Laboratory of Advanced Electromagnetic Engineering and TechnologyHuazhong University of Scienceand TechnologyWuhan 430074China

Bipolar medium-voltage DC(MVDC)and lowvoltage DC(LVDC)grids have the advantages of flexible integration of distributed renewable-energy generation and reliable power *** order to achieve voltage conversion,power transfer,and electrical isolation for bipolar MVDC and LVDC grids,a high-power DC-DC converter is ***,this paper proposes an isolated bipolar modular multilevel DCDC converter(BiMMDC)with power self-balancing capability for interconnection of MVDC and LVDC *** proposed BiMMDC consists of two series connected MMCs in the MV stage to configure a bipolar MVDC interface,and interleaved converters combined with a dual-transformer are designed in the LV stage to configure the bipolar LVDC interface and to provide a self-balancing *** circuits of two series-connected MMCs and a dual-transformer with interleaved converters are *** that,operation principles of the proposed BiMMDC are introduced,considering balanced/unbalanced power transfer of bipolar LVDC grid and monopolar shortcircuit or open-circuit faults at MVDC *** control scheme is also presented for the proposed BiMMDC under different operating ***,a Matlab simulation and controller hardware-in-the-loop(CHIL)evaluation results are provided to validate the feasibility and effectiveness of the proposed typology and its operating performance.

关键词： Bipolar DC-DC converter equivalent circuit modular monopolar operation multilevel self-balancing

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