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Advancing electrochemical drilling process via coupling of flow field and electric field in pulsating state generated by a novel tube tool

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Chinese Journal of Aeronautics 2024年第4期37卷 542-555页

作者： Liang cheng Xiaolei CHEN Zhisen YE Yongjun ZHANG State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment Guangdong University of TechnologyGuangzhou 510006China Guangdong Key Laboratory of Advanced Manufacturing Technology of Marine Energy Equipment Guangdong University of TechnologyGuangzhou 510006China Guangzhou Key Laboratory of Nontraditional Machining and Equipment Guangdong University of TechnologyGuangzhou 510006China

This paper introduces an improvement to electrochemical drilling process by coupling flow field and electric field in pulsating state. A novel tube with half-wedged shape at the end(HW-tube) is prepared, with both sidewall and wedged part of the HW-tube insulated. Only the flat part is utilized to provide electric field for electrochemical drilling. By rotating the HW-tube, both flow field and electric field in pulsating state are generated, alternating in different positions within the inter-electrode gap(IEG). The pulsating flow field enhances the mass transfer process, while pulsating electric field disperses material dissolution process and distribution of electrolytic byproducts. Both pulsating fields are coupled at the same frequency, further enhancing the electrochemical drilling process. Simulation results indicate that both flow field and electric field in pulsating state are generated. Compared to the traditional tube, the HW-tube significantly reduces the number of residual particles in IEG, and this number is further reduced by increasing the rotation speed. Experimental results reveal that the surface quality and dimensional uniformity of small hole are improved with HW-tube. With feed rate of 2.22 mm/min, a small hole with diameter of 1.52± 0.017 mm is drilled, resulting in a surface roughness of 0.331 μm.

关键词： Small holes Electrochemical drilling Tools Pulsating flow field Pulsating electric field

The evolutionary trajectory of the rural settlements in Southern Jiangsu in the past 20 years:From the perspective of urbanization and land use

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Journal of Geographical Sciences 2024年第8期34卷 1615-1635页

作者： CHEN Feiyu CHEN cheng Key Laboratory of Watershed Geographic Sciences Nanjing Institute of Geography and LimnologyCASNanjing 210008China Nanjing College University of Chinese Academy of SciencesNanjing 211135China

For a long time,due to lack of accurate data covering large areas,it is difficult to capture the continuous spatial evolutionary trajectory of rural settlements shaped by rapid urbanization and rural land use *** fill this gap,based on theoretical analysis this paper systemically detected the changing characteristics of scale,spatial morphology,distribution,and land use pattern of rural settlements in Southern Jiangsu in the past 20 years depending on the data of land resource survey in 2009 and *** study suggests that the total area and per capita size of rural settlements declined by 30%and 2%respectively as a result of rural land consolidation and the influx of enormous immigrants from underdeveloped *** spatial density and average shape index dropped by 14%and 44%respectively in the recent decade,indicating an evident trend of decentralization in spatial distribution,and regularization in the spatial ***,residential land within rural settlements decreased by 33%over the past decade while the land for industry and commercial service steadily increased,demonstrating that the function for manufacturing and diversified services had been *** the emerging issue of the aging population and new business opportunities in rural Southern Jiangsu,rural settlements regeneration might be the focus offutureresearch.

关键词： rural settlements spatial morphology land use Southern Jiangsu

A new scheme of PM_(2.5)and O_(3) control strategies with the integration of SOM,GA and WRF-CAMx

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Journal of Environmental Sciences 2024年第4期138卷 249-265页

作者： Wenjiao Duan Xiaoqi Wang Shuiyuan cheng Ruipeng Wang Key Laboratory of Beijing on Regional Air Pollution Control Faculty of Environment and LifeBeijing University of TechnologyBeijing 100124China

Previous air pollution control strategies didn’t pay enough attention to regional collaboration and the spatial response sensitivities,resulting in limited control effects in *** study proposed an effective PM_(2.5)and O_(3) control strategy scheme with the integration of Self-Organizing Map(SOM),Genetic Algorithm(GA)and WRF-CAMx,emphasizing regional collaborative control and the strengthening of control in sensitive *** scheme embodies the idea of hierarchical management and spatial-temporally differentiated management,with SOM identifying the collaborative subregions,GA providing the optimized subregion-level priority of precursor emission reductions,and WRF-CAMx providing response sensitivities for grid-level priority of precursor emission *** Beijing-Tianjin-Hebei and the surrounding area(BTHSA,“2+26”cities)as the case study area,the optimized strategy required that regions along Taihang Mountains strengthen the emission reductions of all precursors in PM_(2.5)-dominant seasons,and strengthen VOCs reductions but moderate NOx reductions in O_(3)-dominant *** spatiotemporally differentiated control strategy,without additional emission reduction burdens than the 14th Five-Year Plan proposed,reduced the average annual PM_(2.5)and MDA8 O_(3) concentrations in 28 cities by 3.2%-8.2% and 3.9%-9.7% respectively in comparison with non-differential control strategies,with the most prominent optimization effects occurring in the heavily polluted seasons(6.9%-18.0%for PM_(2.5)and 3.3%-14.2% for MDA8 O_(3),respectively).This study proposed an effective scheme for the collaborative control of PM_(2.5)and O_(3) in BTHSA,and shows important methodological implications for other regions suffering from similar air quality problems.

关键词： PM_(2.5)and O_(3)control SOM GA WRF-CAMx Bionic algorithm Machine learning

Analysis of piezoelectric semiconductor fibers under gradient temperature changes

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 311-320页

作者： Shuangpeng LI Ruoran cheng Nannan MA Chunli ZHANG Department of Engineering Mechanics Zhejiang UniversityHangzhou 310027China

Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor *** fiber-like structures have wide applications in multi-functional semiconductor *** this paper,a one-dimensional(1D)theoretical model is established to describe the piezotronic responses of a PS fiber under gradient temperature *** theoretical model aims to explain the mechanism behind the resistance change caused by such gradient temperature *** results demonstrate that a gradient temperature change significantly affects the physical fields within the PS fiber,and can induce changes in its surface *** provides important theoretical guidance on the development of piezotronic devices that are sensitive to temperature effects.

关键词： piezoelectric semiconductor(PS)fiber one-dimensional(1D)model piezotronic effect gradient temperature change

An anonymous authentication and secure data transmission scheme for the Internet of Things based on blockchain

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Frontiers of Computer Science 2024年第3期18卷 183-197页

作者： Xingxing CHEN Qingfeng cheng Weidong YANG Xiangyang LUO State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou Institute of Information Science and TechnologyZhengzhou 450001China Henan Key Laboratory of Grain Photoelectric Detection and Control Henan University of TechnologyZhengzhou 450001China Henan Province Key Laboratory of Cyberspace Situation Awareness Zhengzhou Institute of Information Science and TechnologyZhengzhou 450001China

With the widespread use of network infrastructures such as 5G and low-power wide-area networks,a large number of the Internet of Things(IoT)device nodes are connected to the network,generating massive amounts of ***,it is a great challenge to achieve anonymous authentication of IoT nodes and secure data *** present,blockchain technology is widely used in authentication and s data storage due to its decentralization and ***,Fan et *** a secure and efficient blockchain-based IoT authentication and data sharing *** studied it as one of the state-of-the-art protocols and found that this scheme does not consider the resistance to ephemeral secret compromise attacks and the anonymity of IoT *** overcome these security flaws,this paper proposes an enhanced authentication and data transmission scheme,which is verified by formal security proofs and informal security ***,Scyther is applied to prove the security of the proposed ***,it is demonstrated that the proposed scheme achieves better performance in terms of communication and computational cost compared to other related schemes.

关键词： Internet of Things blockchain authentication data transmission

Selection Method for New Energy Output Guaranteed Rates Considering Optimal Energy Storage Configuration

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 539-547页

作者： Xin cheng Tong Wu Wei Yao Yan Yang Guangdong Power Grid Corporation Guangzhou 510620China State Key Laboratory of Advanced Electromagnetic Engineering and Technology and School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The output of new energy represented by wind power and photovoltaic power features volatility and randomness. It is a practical approach to use the guaranteed rate with statistical characteristics to analyze the output coefficient of new energy. However, there is a lack of analysis and demonstration on the value of the new energy output guaranteed rate. To solve this problem, a selection method for the new energy output guaranteed rate considering optimal energy storage configuration is proposed. First, the influence of the new energy output guaranteed rate on the new energy output coefficient is analyzed. Secondly, with the goal of minimizing the comprehensive costs, an optimal configuration model of energy storage based on the output guaranteed rate of new energy is constructed, and particle swarm optimization is used for the optimization solution. Then, according to the optimal energy storage configuration results under different guaranteed rates, a reasonable new energy output guaranteed rate is determined by maximizing the comprehensive benefits obtained from energy storage. Finally, an example applied to the power grid in an area of Guangdong in Southern China is provided to illustrate the effectiveness of the proposed method.

关键词： Energystorage optimization guaranteed output guaranteed rate new energy consumption

Visual experimental study of nanofluids application to promote CO_(2) absorption in a bubble column

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Chinese Journal of Chemical Engineering 2024年第3期67卷 228-237页

作者： Shangyuan cheng Guisheng Qi Yuliang Li Yixuan Yang Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering North University of ChinaTaiyuan 030051China

The addition of dispersed-phase nanoparticles in the liquid phase can enhance the gas-liquid transfer process as the suspended nanoparticles affect the transfer process inside the fluid through microdisturbance or micro-convection *** this article,a high-speed digital camera was used to visualize the bubble behavior of CO_(2) in pure water and nanofluids to examine the effects of CO_(2) gas flow rate,nanoparticle solid content and type on the bubble behavior in the *** CO_(2) absorption performance in three water-based nanofluids were compared in a *** the mass transfer characteristics during CO_(2) bubble absorption and the reasons for the enhanced gas-liquid mass transfer effect of nanoparticles were *** results showed that the presence of nanoparticles affected the formation process of bubbles in the fluid,shortened the bubble detachment time,reduced the detachment diameter,effectively increased the gas-liquid contact area,and improved the bubbles detachment *** system with MCM-41 corresponded to a higher overall mass transfer *** MCM-41 contained surfactant that enhanced foaming behavior in *** prevented the transfer of CO_(2) to some extent,and the CO_(2) absorption by uncalined MCM-41/H_(2)O was 5.34%higher than that by pure *** with SiO_(2) nanoparticles with the same particle size and the same composition,MCM-41 had a higher adsorption capacity and better hydrophilicity due to its larger specific surface area and rich porous structure,which was more favorable to accelerate the collision between nanoparticles and CO_(2) bubbles to cause *** the condition of 0.1%(mass)solid content,the enhancement of CO_(2) absorption process by MCM-41 nanoparticles was more significant and improved by 16.9%compared with pure water.

关键词： Nanofluids CO_(2) absorption Mass transfer MCM-41 Bubble column

Magnetic-field-assisted triboelectric nanogenerator for harvesting multi-directional wave energy

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Nano Research 2024年第8期17卷 7144-7152页

作者： Mengru Ding Jianlong Wang Da Zhao Hengyu Li Xiaojun cheng Jianming Wen Zhong Lin Wang Tinghai cheng Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of SciencesBeijing 101400China School of Nanoscience and Engineering University of Chinese Academy of SciencesBeijing 100049China Guangzhou Institute of Blue Energy Guangzhou 510555China College of Engineering Zhejiang Normal UniversityJinhua 321004China School of Materials Science and Engineering Georgia Institute of TechnologyAtlantaGA 30332-0245USA

Ocean wave energy is a significant and promising source of renewable ***,the energy harvesting is challenging due to the multi-directional nature of *** paper proposes a magnetic-field-assisted triboelectric nanogenerator(MFATENG)for harvesting multi-directional wave *** incorporating a magnetic field,the planar motion of the pendulum is converted into spatial motion,increasing the triggering of multilayered TENG(M-TENG)and enhancing the output energy of the *** results demonstrate that the output energy of the MFA-TENG is increased by 73%by utilizing the magnetic ***,a spring model based on the origami-structured M-TENG is established to analyze the effect of different equivalent stiffnesses on the performance of the M-TENG,aiming to obtain optimal output *** results showcase the impressive output performance of the M-TENG,generating outputs of 250 V,18μA,and 255 ***,the proposed MFA-TENG effectively harvests multi-directional wave energy under water-wave driven *** study significantly enhances the ability of the MFA-TENG to harvest multi-directional wave energy and presents a promising approach for self-powered marine monitoring in the future.

关键词： triboelectric nanogenerator magnetic-field-assisted spring model multi-directional wave energy

Intelligent gold nanocluster for effective treatment of malignant tumor via tumor-specific photothermal–chemodynamic therapy with AIE guidance

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National Science Review 2024年第5期11卷 326-342页

作者： Feng Liu Tianfeng Yang Xiaowei Chang Li Chen cheng cheng Xiuhong Peng Haihu Liu Yanmin Zhang Xin Chen School of Energy and Power Engineering Xi'an Jiaotong University Department of Chemical Engineering Shaanxi Key Laboratory of Energy Chemical Process IntensificationInstitute of Polymer Science in Chemical Engineering School of Chemical Engineering and Technology Xi'an Jiaotong University School of Pharmacy Health Science Center Xi'an Jiaotong University

Precise and efficient therapy of malignant tumors is always a challenge. Herein, gold nanoclusters co-modified by aggregation-induced-emission（AIE） molecules, copper ion chelator（acylthiourea） and tumor-targeting agent（folic acid） were fabricated to perform AIE-guided and tumor-specific synergistic therapy with great spatio-temporal controllability for the targeted elimination and metastasis inhibition of malignant tumors. During therapy, the functional gold nanoclusters（Au NTF） would rapidly accumulate in the tumor tissue due to the enhanced permeability and retention effect as well as folic acid-mediated tumor targeting, which was followed by endocytosis by tumor cells. After that, the overexpressed copper ions in the tumor cells would trigger the aggregation of these intracellular Au NTF via a chelation process that not only generated the photothermal agent in situ to perform the tumor-specific photothermal therapy damaging the primary tumor, but also led to the copper deficiency of tumor cells to inhibit its ***, the copper ions were reduced to cuprous ions along with the chelation, which further catalysed the excess H2O2in the tumor cells to produce cytotoxic reactive oxygen species, resulting in additional chemodynamic therapy for enhanced antitumor efficiency. The aggregation of Au NTF also activated the AIE molecules to present fluorescence, which not only imaged the therapeutic area for real-time monitoring of this tumor-specific synergistic therapy, but also allowed us to perform near-infrared radiation at the correct time point and location to achieve optimal photothermal therapy. Both in vitro and in vivo results revealed the strong tumor elimination, effective metastasis inhibition and high survival rate of tumor-bearing mice after treatment using the Au NTF nanoclusters, indicating that this AIE-guided and tumor-specific synergistic strategy could offer a promising approach for tumor therapy.

关键词： AIE-guided precise tumor treatment copper-dependent photothermal therapy copper-triggered chemodynamic therapy primary tumor elimination copper-plunder-induced metastasis inhibition