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A review of recent advances in the effects of surface and interface properties on marine propellers

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Friction 2024年第2期12卷 185-214页

作者： manfu zhu Liran ma State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

marine propellers are important propulsion devices for both surface ships and underwater *** severe environmental problems have required further performance enhancement for ***,traditional methods to improve propeller performances through geometrical and structural optimizations have been extensively investigated,while the underlying mechanisms of the effects of surface and interface properties on marine propellers are still far from being fully *** paper presented a comprehensive review of recent advances in the effects of surface and interface properties,such as surface roughness and surface wettability,on marine propellers with an emphasis on the significant improvements in both hydrodynamic and cavitation performances,hoping to arouse more in-depth investigations in the field of surface/interface science and technologies on marine propellers,and also promote the state-of-the-art technologies,such as superlubricity technology,into practical applications.

关键词： marine propellers hydrodynamics cavitation surface roughness surface wettability

High-speed flexible near-infrared organic photodiode for optical communication

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National Science Review 2024年第03期11卷 227-238页

作者： Yu zhu Hongbin Chen Ruiman Han Hao Qin Zhaoyang Yao Hang Liu Yanfeng ma Xiangjian wan Guanghui Li Yongsheng Chen The Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer materials Institute of Polymer ChemistryTianjin Key Laboratory of Functional Polymer Materials College of Chemistry and Renewable Energy Conversion and Storage Center(RECAST) Nankai University State Key Laboratory of Elemento-Organic Chemistry Nankai University

Optical communication is a particularly compelling technology for tackling the speed and capacity bottlenecks in data communication in modern society. Currently, the silicon photodetector plays a dominant role in high-speed optical communication across the visible-near-infrared spectrum. However, its intrinsic rigid structure, high working bias and low responsivity essentially limit its application in next-generation flexible optoelectronic devices. Herein, we report a narrow-bandgap non-fullerene acceptor（NFA） with a remarkable π-extension in the direction of both central and end units（CH17） with respect to the Y6 series, which demonstrates a more effective and compact 3D molecular packing, leading to lower trap states and energetic disorders in the photoactive film. Consequently, the optimized solution-processed organic photodetector（OPD） with CH17 exhibits a remarkable response time of 91 ns（λ = 880 nm） due to the high charge mobility and low parasitic capacitance, exceeding the values of most commercial Si photodiodes and all NFA-based OPDs operating in self-powered mode. More significantly, the flexible OPD exhibits negligible performance attenuation（maintains 96% of its initial performance even after 550 h of indoor exposure. Furthermore, the high-speed OPD demonstrates a high data transmission rate of 80 MHz with a bit error rate of 3.5 × 10-4, meaning it has great potential in next-generation high-speed flexible optical communication systems.

关键词： flexible organic photodetector high-speed NIR organic photodetector optical communication light fidelity narrow-bandgap non-fullerene acceptors

Two-Dimensional Metallophthalocyanine Nanomaterials for Electrocatalytic Energy Conversion

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Energy & Environmental materials 2024年第4期7卷 364-385页

作者： Xinqi wang Shaohui Sun Jiahao Yao Hao wan Renzhi ma Wei ma School of Chemical Engineering and Zhongyuan Critical Metals Laboratory Zhengzhou University Research Center for materials Nanoarchitectonics (maNA) National Institute for Materials Science (NIMS)

Crowing energy demand drives the rapid development of clean and reliable energy *** the past years,the exploration of novel materials with considerable efficiency and durability has drawn attention in the area of elec... 详细信息

关键词： conjugated nanostructure electrocatalysis 2D metallophthalocyanines

Measuring Financial Systemic Risk:Net Liability Clearing Mechanism and Contagion Effect

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Journal of Systems Science & Complexity 2024年第3期37卷 1114-1146页

作者： ma Jiali zhu Shushang LI Duan College of Big Data Statistics Guizhou University of Finance and EconomicsGuiyang 550025China School of Business Sun Yat-Sen UniversityGuangzhou 510275China School of Data Science City University of Hong KongHong Kong 999077China

Following the framework of E-N model(Eisenberg and Noe,2001),the authors consider a new clearing mechanism based on net liabilities among financial institutions since the liabilities between the counterparties should be deducted accordingly when clearing in *** the basis for systemic risk measurement,similar to the original E-N model,the authors first establish some good properties for the clearing payment vector according to a more general ***,the authors investigate how risk spreads among institutions through the liability network forming the risk contagion ***,the authors illustrate with a specific example that the original E-N clearing mechanism may misidentify the systemic important institutions,and theoretically show that it may also overestimate the risk compared with the netting clearing mechanism.

关键词： Clearing mechanism contagion net liability network systemic risk

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machine learning assisted adsorption performance evaluation of biochar on heavy metal

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Frontiers of Environmental Science & Engineering 2024年第5期18卷 29-42页

作者： Qiannan Duan Pengwei Yan Yichen Feng Qianru wan Xiaoli zhu Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity College of Urban and Environmental SciencesNorthwest UniversityXi’an710127China Department of Environment Science Shaanxi Normal UniversityXi’an710062China

Heavy metals(HMs)represent pervasive and highly toxic environmental pollutants,known for their long latency periods and high toxicity levels,which pose significant challenges for their removal and ***,the removal of heavy metals from the environment is crucial to ensure the water *** materials,known for their intricate pore structures and abundant oxygen-containing functional groups,are frequently harnessed for their effectiveness in mitigating heavy metal ***,conventional tests for optimizing biochar synthesis and assessing their heavy metal adsorption capabilities can be both costly and *** address this challenge,this paper proposes a data-driven machine learning(ML)approach to identify the optimal biochar preparation and adsorption reaction conditions,with the ultimate goal of maximizing their adsorption *** utilizing a data set comprising 476 instances of heavy metal absorption by biochar,seven classical integrated models and one stacking model were trained to rapidly predict the efficiency of heavy metal adsorption by *** predictions were based on diverse physicochemical properties of biochar and the specific adsorption reaction *** results demonstrate that the stacking model,which integrates multiple algorithms,allows for training with fewer samples to achieve higher prediction accuracy and improved generalization ability.

关键词： machine learning Biochar Heavy metal Adsorption efficiency

An Innovation of Evaluation and Design of Vehicle Acceleration Sound Based on EEG Signals

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Journal of Bionic Engineering 2024年第1期21卷 344-361页

作者： Liping Xie XinYou Lin wan Chen Zhien Liu Yawei zhu College of Mechanical Engineering&Automation Fuzhou UniversityFuzhou 350108China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of TechnologyWuhan 430070China

There is a bottleneck in the design of vehicle sound that the subjective perception of sound quality that combines multiple psychological factors fails to be accurately and objectively ***,EEG signals are introduced in this paper to investigate the evaluation and design method of vehicle acceleration sound with powerful sound ***,the experiment of EEG acquisition and subjective evaluation under the stimulation of powerful vehicle sounds is conducted,respectively,then three physiological EEG features of PSD_β,PSD_γand DE are constructed to evaluate the vehicle sounds based on the correlation analysis ***,the Adaptive Genetic Algorithm(AGA)is proposed to optimize the Elman model,where an intelligent model(AGA–Elman)is constructed to objectively predicate the perception of subjects for the vehicle sounds with powerful sound *** results demonstrate that the error of the constructed AGA–Elman model is only 2.88%,which outperforms than the traditional BP and Elman model;Finally,two vehicle acceleration sounds(Design1 and Design2)are designed based on the constructed AGA–Elman model from the perspective of order modulation and frequency modulation,which provide the acoustic theoretical guidance for the design of vehicle sound incorporating the EEG signals.

关键词： EEG signal Brain activity analysis Vehicle sound design Adaptive genetic algorithm-Elman model

Copper Catalyzed Enantioconvergent Nucleophilic Substitutions

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Chinese Journal of Chemistry 2024年第10期42卷 1161-1174页

作者： Chunxi Huang Zilong wan Aoping zhu Caiyou Chen College of Chemistry and Molecular Sciences Wuhan UniversityWuhanHubei 430072China Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules and College of Chemistry and Chemical Engineering Hubei UniversityWuhanHubei 430062China

As a versatile earth-abundant transition metal,Cu has long been widely applied in the C—C and C—X bond forming *** for now,low-valent Cu(Ⅰ)is known to reduce the redox active electrophiles via an SET pathway to give the corresponding radical and Cu(Ⅱ)*** resulting Cu(Ⅱ)species can interact with the radical via the out-sphere pathway,affording the coupling ***,Cu(Ⅱ)can trap the radical through the inner-sphere process to generate Cu(Ⅲ)species and then realize challenging bond formations due to the facile reductive elimination of Cu(Ⅲ)*** copper catalysis has been widely applied in arylations of various nucleophiles,copper-catalyzed enantioconvergent nucleophilic substitutions of racemic alkyl electrophiles have been less explored,likely due to the difficulties in overcoming the reduction potential of alkyl electrophiles,elimination of side reactions,and enantiomeric *** order to overcome the high reduction potential of alkyl electrophiles,the photo-induced strategy has been developed under mild *** alternative strategy with new anionic tridentate ligands has also been reported in this *** review summarizes recent developments in copper-catalyzed enantioconvergent nucleophilic substitutions of alkyl electrophiles by various nucleophiles to realize C—N,C—C,C—B,C—P and C—O bond formations and their brief mechanistic studies.

关键词： Enantioconvergent Nucleophilic substitution Copper Radical reactions Photocatalysis Asymmetric catalysis

Health-oriented strategies are needed to optimize China’s 2025 clean air action plan

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Science Bulletin 2024年第13期69卷 2007-2008页

作者： Tao Xue Ning Kang Wei wan Tong zhu Institute of Reproductive and Child Health/National Health Commission Key Laboratory of Reproductive Health and Department of Epidemiology and Biostatistics/Ministry of Education Key Laboratory of Epidemiology of major Diseases(PKU) School of Public HealthPeking University Health Science CentreBeijing 100191China State Environmental Protection Key Laboratory of Atmospheric Exposure and Health Risk management Center for Environment and HealthPeking UniversityBeijing 100871China Advanced Institute of Information Technology Peking UniversityHangzhou 311215China Clean Air Asia Beijing 100600China College of Environmental Sciences and Engineering Peking UniversityBeijing 100871China

Recently,China’s State Council issued the Continuous Improvement of Air Quality Action Plan(hereafter,the third action plan),which follows the Air Pollution Prevention and Control Action Plan(2013–2017)(hereafter,the first action plan)and the Three-Year Action Plan for Winning the Blue Sky Defense Battle(2018–2020)(hereafter the second action plan).The first two action plans yielded nationwide health benefits[1–3],from improving lung function[4]to saving medical expenditures[5].Based on our previous estimates[6],due to reductions in the fine particulate matter(PM2.5)level,implementation of the first and second action plans was expected to increase life expectancy by 2.11 and 3.68 months.

关键词： action hereafter nationwide

Review on heat-to-power conversion technologies for hypersonic vehicles

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Chinese Journal of Aeronautics 2024年第5期37卷 148-179页

作者： Yinke QI Xiaofeng ma Peixue JIANG Yinhai zhu Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Beijing Key Laboratory of CO_(2)Utilization and Reduction Technology Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China

Hypersonic vehicles have enormous military and economic value,while their power and thermal protection demands will increase substantially with the rise in mach number and *** the tremendous high-quality heat on the vehicle surface and engine wall into electrical energy through heat-to-power technologies will not only play a role in thermal protection,but also supply power for the *** paper provides a comprehensive review of heat-to-power conversion technologies on hypersonic vehicles,including the indirect conversion of Brayton and Rankine cycles,direct conversion of thermoelectric materials,and combined *** the open Brayton cycle with hydrocarbon fuel as the working fluid,the Power-to-Weight Ratio(PWR)can achieve the highest,at around 1.8,due to the high PWR of the hydrocarbon fuel turbine and the few components of the ***,its work capacity is limited by the flow rate of the supplied *** closed Brayton cycle can maintain a relatively high PWR,ranging from 0.2 to 0.8,while achieving relatively high output power and conversion *** Rankine cycle has a higher PWR,its range is close to that of the closed Brayton cycle,peaking at about *** thermoelectric materials technology has a small power generation level,making it more suitable for scenarios with low power *** review provides a basis for selecting and developing heat-to-power conversion technologies on hypersonic vehicles.

关键词： Hypersonic vehicles Heat-to-power conversion Brayton cycle Rankine cycle Thermoelectric materials

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