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Cobalt(Ⅲ)hydride HAT mediated enantioselective intramolecular hydroamination access to chiral pyrrolidines

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science China Chemistry 2024年第6期67卷 2002-2008页

作者： Qi Meng Tao Qin Huanran Miao ge Zhang Qian Zhang Jilin Province Key laboratory of Organic Functional Molecular Design&synthesis Department of ChemistryNortheast Normal UniversityChangchun130024China state Key laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai200032China

Enantioenriched pyrrolidines and derivatives are ubiquitous substructures in compounds of importance to medicinal and biological ***,we report an efficient cobalt-catalyzed intramolecular asymmetric hydroamination reaction that produces chiral pyrrolidines with good to excellent yield and *** with previously reported radicalinvolved methodologies for enantioenriched pyrrolidines,these conditions feature two elegant versatilities,enabling(1)the use of cobalt-catalyzed hydrogen atom transfer(HAT)to generate organocobalt intermediates that bring radical reaction to organometallic chemistry,and(2)enantioselective intramolecular C-N bond forging through an s_(N)2-like displacement involving dynamic kinetic resolution(DKR).This approach provides a new alternative and efficient methodology for enantioselective radical-involved C-N bond construction that can be used in the synthesis of both chiral pyrrolidines and homologous nitrogen heterocycles.

关键词： asymmetric catalysis radical hydroamination cobalt catalysis hydrogen atom transfer

Energy consumption optimization for edge computing-supported cellular networks based on optimal transport theory

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science China(Information sciences) 2024年第2期67卷 201-218页

作者： Xiangyu lV Xiaohu ge Yi ZHONg Qiang lI Yong XIAO school of Electronic Information and Communications Huazhong University of Science and Technology

With advancements in mobile communication technologies, there have been multiple user device(UD) connections to cellular networks. Because of changes in the spatial distribution of UDs and application requirements, the traditional offloading mechanism based on the nearest distance will result in heavy loads for some base stations(Bss). Because there is a high-order relationship between the energy consumption of the Bs processing tasks and the number of computing tasks, the traditional offloading mechanism will result in high energy consumption, and UD’s offloading decision must be dynamically adjusted. The offloading decision of UDs is optimized based on detailed information about various parameters associated with a network from the standpoint of distribution. This information includes details regarding the spatial distribution of UDs,application requirements, and the offloading period of computing tasks. Based on optimal transport theory,an energy consumption optimization algorithm is suggested to lower the total amount of energy consumed by the offloading process of UDs’ computing tasks by reasonably planning the offloading Bss of the UDs in the networks. The simulation results show that the proposed offloading mechanism based on energy consumption optimization reduces the total energy consumption of the offloading process by 28.09% when compared to the traditional offloading mechanism, and the traffic managed by each Bs is balanced.

关键词： optimal transport theory edge computing energy consumption reduction dynamic voltage frequency scaling

Constructal design of a rectangular parallel phase change microchannel in a three-dimensional electronic device

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science China(Technological sciences) 2024年第5期67卷 1381-1390页

作者： ZHANg JiWen FENg HuiJun CHEN lingen ge Yanlin Institute of Thermal science and Power Engineering Wuhan Institute of TechnologyWuhan430205China College of Power Engineering Naval University of EngineeringWuhan430033China Hubei Provincial Engineering Technology Research Center of green Chemical Equipment Wuhan430205China school of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan430205China

Based on constructal theory,a rectangular parallel phase change microchannel model in a three-dimensional electronic device(TDED)is established with R134a as the cooling *** on the minimization of a complex function(CF)composed of linear weighting sum of maximum temperature difference and pumping power consumption,constructal design of the TDED is conducted first;and then,maximum temperature difference and pumping power consumption are minimized by non-dominated sorting genetic algorithm-II *** results reveal that there exist an optimal mass flow rate(0.0012 kg/s)and a quadratic optimal aspect ratio(AR)(0.39)of the microchannel which lead to quadratic minimum CF(0.817).Compared with the original value,the CF after optimization is reduced by 18.34%.Reducing the inlet temperature of cooling fluid and microchannel number appropriately can help to enhance the overall performance of *** using the artificial neural network and genetic algorithms in the toolboxes of Matlab software,the optimal AR gained in the Pareto solution set is located between 0.2–*** smallest deviation index among three discussed strategies is 0.346,and the corresponding optimal AR is 0.413,which is selected as the optimal design strategy of the microchannel in the TDED under multiple *** findings in this study can serve as theoretical guides for thermal designs of electronic devices.

关键词： constructal theory parallel microchannel evaporation phase change three-dimensional electronic device multi-objective optimization artificial neural network

Energy and exergy analyses and optimizations for two-stage TEC driven by two-stage TEg with Thomson effect

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science China(Technological sciences) 2024年第4期67卷 1077-1093页

作者： CHEN lingen ge Yanlin FENg HuiJun REN TingTing Institute of Thermal science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China Hubei Provincial Engineering Technology Research Center of green Chemical Equipment Wuhan 430205China school of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China

Based on the non-equilibrium thermodynamics and energy and exergy analyses,a thermodynamic model of two-stage thermoelectric(TE)cooler(TTEC)driven by two-stage TE generator(TTEg)(TTEg-TTEC)combined TE device is established with involving Thomson effect by fitting method of variable physical parameters of TE *** total number of TE elements as constraint,influences of number distributions of TE elements on three device performance indictors,that is,cooling load,maximum COP and maximum exergetic efficiency,are *** number distributions of TE elements are optimized with three maximum performance indictors as the objectives,*** of hot-junction temperature of TTEg and coldjunction temperature of TTEC on optimization results are analyzed,and difference between optimization results corresponding to three performance indicators are *** performance intervals and optimal variable intervals are *** of Thomson effect on three general performance indicators,three optimal performance indicators and optimal variables are comparatively *** effect reduces three general performance indicators and three optimal performance indicators of *** hot-and cold-junction temperatures of TTEg and TTEC are 450,305,325 and 295 K,respectively,Thomson effect reduced maximum cooling load,maximum COP and maximum exergetic efficiency from 9.528 W,9.043×10^(-2)and2.552%to 6.651 W,6.286×10^(-2)and 1.752%,respectively.

关键词： non-equilibrium thermodynamics cooling load COP exergetic efficiency combined thermoelectric device performance optimization

An Analytical Method for Delineating Feasible Region for PV Integration Capacities in Net-zero Distribution systems Considering Battery Energy storage system Flexibility

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Journal of Modern Power systems and Clean Energy 2024年第2期12卷 475-487页

作者： shida Zhang shaoyun ge Hong liu guocheng Hou Chengshan Wang school of Electrical and Information Engineering Tianjin UniversityTianjin 300072China

To provide guidance for photovoltaic(PV)system integration in net-zero distribution systems(Dss),this paper proposes an analytical method for delineating the feasible region for PV integration capacities(PVICs),where the impact of battery energy storage system(BEss)flexibility is ***,we introduce distributionally robust chance constraints on network security and energy/carbon net-zero requirements,which form the upper and lower bounds of the feasible ***,the formulation and solution of the feasible region is *** resulting analytical expression is a set of linear inequalities,illustrating that the feasible region is a polyhedron in a high-dimensional space.A procedure is designed to verify and adjust the feasible region,ensuring that it satisfies network loss constraints under alternating current(AC)power *** studies on the 4-bus system,the IEEE 33-bus system,and the IEEE 123-bus system verify the effectiveness of the proposed *** is demonstrated that the proposed method fully captures the spatio-temporal coupling relationship among PVs,loads,and BEsss,while also quantifying the impact of this relationship on the boundaries of the feasible region.

关键词： Net-zero distribution system photovoltaic(PV)integration capacity feasible region battery energy storage system(BEss).

Carbon efficiency modeling and optimization of solar-powered cellular networks

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science China(Information sciences) 2024年第5期67卷 228-243页

作者： Yuxi ZHAO Xiaohu ge Wen YAN Tao HAN Yi ZHONg school of Electronic Information and Communications Huazhong University of Science and Technology Huawei Technology Co. Ltd.

As wireless communication traffic experiences rapid growth, the carbon emissions caused by the communication industry are also on the rise. To achieve “carbon neutrality”, researchers are considering the use of renewable energy sources to power cellular networks, thereby reducing carbon emissions. However, a challenge arises when using renewable energy, specifically owing to the unpredictable nature of both the energy consumption of the cellular network and the power generation from renewable sources. This inconsistency results in low renewable energy utilization and reduced carbon efficiency. Herein, we construct a carbon efficiency model of solar-powered cellular networks using practical data from solar radiation. We propose a mechanism that alternately optimizes the performance of the renewable energy network and the cellular network. This approach is based on convex optimization theory and the Dinkelback algorithm, and it leads to the design of a carbon efficiency optimization algorithm. This algorithm aims to improve the carbon efficiency of cellular networks and reduce their carbon emissions. simulation results demonstrate that our optimization scheme yields a maximum improvement of 2.56 × 108bps/g in the carbon efficiency of the cellular network as compared to conventional power allocation schemes such as the traditional water filling method and heuristic energy sharing and charge/discharge algorithms.

关键词： cellular networks renewable energy carbon efficiency convex optimization theory dinkelbach

Constructal design of printed circuit recuperator for s-CO_(2)cycle via multi-objective optimization algorithm

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science China(Technological sciences) 2024年第1期67卷 285-294页

作者： DAN Zhisong FENg HuiJun CHEN lingen lIAO NaiBing ge Yanlin Institute of Thermal science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China College of Power Engineering Naval University of EngineeringWuhan 430033China Hubei Provincial Engineering Technology Research Center of green Chemical Equipment Wuhan 430205China school of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China AECC Hunan Aviation Powerplant Research Institute Zhuzhou 412002China

Based on a constructal theory,the structure design of a printed circuit recuperator with a semicircular heat transfer channel for supercritical CO_(2)cycle is carried ***,a complex function composed of weighted sum of the reciprocal of total heat transfer rate and total pumping power consumption is regarded as an optimization objective,and total volumes of the recuperator and heat transfer channel are regarded as *** optimal heat transfer channel radius and minimum complex function of the recuperator are *** turns out that heat transfer rate,pumping power consumption,and complex function under the optimal construct of recuperator are reduced by 15.10%,82.44%,and 32.33%,*** exists the optimal single plate channel number which results in the double minimum complex ***,for the purpose of minimizing the reciprocal of heat transfer rate and pumping power consumption,NsgA-II algorithm is used to achieve multi-objective optimization,and the minimum deviation index derived by the decision-making methods is 0.076,which can be taken as multi-objective optimal design scheme for printed circuit recuperator with semicircular heat transfer *** findings presented here can serve as theoretical recommendations for the structure design of printed circuit recuperator.

关键词： constructal theory supercritical CO_(2)cycle printed circuit heat exchanger heat transfer rate pumping power consumption multi-objective optimization

Optimal Control of service Rates of Discrete-Time(s,Q)Queueing-Inventory systems with Finite Buffer

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Journal of systems science and systems Engineering 2024年第3期33卷 261-280页

作者： l.Iniya B.sivakumar g.Arivarignan school of Mathematics Madurai Kamaraj UniversityMaduraiTamilnaduIndia Department of statistics Manonmaniam Sundaranar UniversityTirunelveliTamilnaduIndia

This article,we develop an optimal policy to control the service rate of a discrete time queueing-inventory system with finite *** customers arrive according to a Bernoulli process and the service time for the customers are *** the buffer size attains its maximum,any arriving new customers are considered to be *** customers are served one by one according to FCFs rule and each customers request random number of *** inventory is replenished according to a(s,Q)inventory policy with geometric lead *** main objectives of this article are to determine the service rates to be employed at each slot so that the long run expected cost rate is minimized for fixed inventory level and fixed buffer size and to minimize the expected waiting time for a fixed inventory level and fixed buffer *** problems are modelled as Markov decision *** establish the existence of a stationary policy and employ linear programming method to find the optimal service *** provide some numerical examples to illustrate the behaviour of the model.

关键词： Queueing-inventory system discrete time batch demand-Markov decision process

A local-global Attention Fusion Framework With Tensor Decomposition for Medical Diagnosis

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IEEE/CAA Journal of Automatica sinica 2024年第6期11卷 1536-1538页

作者： Peishu Wu Han li liwei Hu Jirong ge Nianyin Zeng Department of Instrumental and Electrical Engineering Xiamen UniversityFujian 361005China Key Research laboratory of Osteoporosis syndrome genomics Fujian Academy of Chinese Medical SciencesFuzhou 350003China

Dear Editor,In this letter,a novel hierarchical fusion framework is proposed to address the imperfect data property in complex medical image analysis(MIA)*** particular,by combining the strengths of convolutional neural networks(CNNs)and transformers,the enhanced feature extraction,spatial modeling,and sequential context learning are realized to provide comprehensive insights on the complex data *** of information in different level is enabled via a multi-attention fusion mechanism,and the tensor decomposition methods are adopted so that compact and distinctive representation of the underlying and high-dimensional medical image features can be accomplished[1].It is shown from the evaluation results that the proposed framework is competitive and superior as compared with some other advanced algorithms,which effectively handles the imperfect property of inter-class similarity and intra-class differences in diseases,and meanwhile,the model complexity is reduced within an acceptable level,which benefits the deployment in clinic *** has assumed a pivotal role in numerous critical clinical scenarios,where sophisticated image analysis techniques have proven instrumental in augmenting medical decision-making,facilitating individualized therapeutic interventions,and enhancing patient prognostication[2]−[4].

关键词： handle image property