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Rare Metals 2024年第4期43卷 1570-1579页

作者： Gang dong Cong Huang Fei-Yang Chen Xue-Qin liu zhen li Xiao-li Su Tao Zeng Yun-Xia Chen Yi-Huang Chen Yang Wang School of Materials Science and Engineering Jingdezhen Ceramic UniversityJingdezhen333403China Faculty of Materials Science and Chemistry China University of GeosciencesWuhan430074China College of Chemistry and Materials Engineering Wenzhou UniversityWenzhou325035China

Given the clean and inexhaustible solar energy from solar light,photocatalytic ammonia synthesis is extremely ***,high electron-hole recombination rates and insufficient active sites severely limited N2 photoreaction ***,we designed and fabricated FeCu alloy nanoparticles anchored on carbon nitride nanosheets with excellent photocatalyt ic ammonia synthesis *** a coupler between Fe and carbon nitride,Cu promotes the separation of photogenerated charge carriers in carbon nitride under solar light irradiation,and renters the semiconductor a forceful electron donor for the Fe active *** accumulated electrons at Fe sites furtherly facilitated the adsorption and activation of the molecular ***,the uniform dispersed FeCu alloy nanoparticles were on carbon nitride nanosheets enhanced the stability of photocataly tic nitrogen reduction reaction,making the artificial photocataly tic ammonia synthesis more sustainable for *** work highlights that a direct electron transfer channel can be used to regulate the photochemical nitrogen fixation network.

关键词： Photocatalytic N_2 fixation Carbon nitride FeCu alloy Active sites Hydrogenation pathway

Deformation and stability of the seawall,considering the strength uncertainty of cement mixing piles

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 483-501页

作者： Yuansheng YU lingling li Xiangmiao KONG Chengyuan li zhen GUO Key Laboratory of Offshore Geotechnics and Material of Zhejiang Province College of Civil Engineering and ArchitectureZhejiang UniversityHangzhou310058China Hainan Institute Zhejiang UniversitySanya572000China Ninghai Highway and Transportation Management Center Ningbo315600China Ninghai Traffic Engineering Construction Management Institute Ningbo315600China

The cement mixing (CM) pile is a common method of improving soft offshore ground. The strength growth of CM piles under complex conditions is affected by many factors, especially the cement and moisture contents, and shows significant uncertainty. To investigate the stochasticity of the early strength of CM piles and its impact on the displacement and stability of a seawall, a series of laboratory tests and numerical analyses were carried out in this study. Vane shear tests were conducted on the cement-solidified soil to determine the relationships between the undrained shear strength s_(u) of the cement soil curing in the seawater and the cement content a_(c), as well as the in situ soil moisture content w. It can be inferred that the 24 h undrained shear strength follows a normal distribution. A numerical model considering the random CM pile strength was established to investigate the deformation of the seawall. Due to the uncertainty of CM pile strength, the displacement of the seawall demonstrates a certain discreteness. The decrease of the mean undrained shear strength of CM piles causes a corresponding increase in the average displacement of the seawall. When the mean strength of CM piles is lower than a certain threshold, there is a risk of instability. Furthermore, the heterogeneity of the strength within an individual CM pile also has an impact on seawall displacement. Attention should be paid to the uncertainty of CM pile strength to control displacement and stability.

关键词： Construction uncertainty Cement mixing(CM)pile Strength of cement soil Seawall stability Random finite element method(RFEM) Monte Carlo simulation(MCS)

Dielectric Constant Calculation of Poly(vinylidene fluoride)Based on Finite Field and Density Functional Theory

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Chinese Journal of Polymer Science 2024年第5期42卷 655-662,I0009页

作者： Yong-Zhi lin Lu-Kun Feng Ya-dong li Chao-Fan Chang Cai-zhen Zhu Ming-liang Wang Jian Xu College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen518055China Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu610041China

In this study,we proposed a novel method that integrates density functional theory(DFT)with the finite field method to accurately estimate the polarizability and dielectric constant of *** approach effectively accounts for the influence of electronic and geometric conformation changed on the dielectric *** validated our method using polyethylene(PE)and polytetrafluoroethylene(PTFE)as benchmark materials,and found that it reliably predicted their dielectric ***,we explored the impact of conformation variations in poly(vinylidene fluoride)(PVDF)on its dielectric constant and *** resulting dielectric constants ofα-andγ-PVDF(3.0)showed excellent agreement with crystalline PVDF in *** findings illuminate the relationship between PVDF’s structural properties and its electrical behavior,offering valuable insights for material design and applications.

关键词： Dielectric constant PVDF Finite field DFT

For LEO Satellite Networks: Intelligent Interference Sensing and Signal Reconstruction Based on Blind Separation Technology

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China Communications 2024年第2期21卷 85-95页

作者： Chengjie li lidong Zhu zhen Zhang The Key Laboratory for Computer Systems of State Ethnic Affairs Commission School of Computer Science and Technology(Southwest Minzu University)Chengdu 610000China National Key Laboratory of Science and Technology on Communications(University of Electronic Science and Technology of China) Chengdu 610000China College of Computer Science(Sichuan University) Chengdu 610000China

In LEO satellite communication networks,the number of satellites has increased sharply, the relative velocity of satellites is very fast, then electronic signal aliasing occurs from time to time. Those aliasing signals make the receiving ability of the signal receiver worse, the signal processing ability weaker,and the anti-interference ability of the communication system lower. Aiming at the above problems, to save communication resources and improve communication efficiency, and considering the irregularity of interference signals, the underdetermined blind separation technology can effectively deal with the problem of interference sensing and signal reconstruction in this scenario. In order to improve the stability of source signal separation and the security of information transmission, a greedy optimization algorithm can be executed. At the same time, to improve network information transmission efficiency and prevent algorithms from getting trapped in local optima, delete low-energy points during each iteration process. Ultimately, simulation experiments validate that the algorithm presented in this paper enhances both the transmission efficiency of the network transmission system and the security of the communication system, achieving the process of interference sensing and signal reconstruction in the LEO satellite communication system.

关键词： blind source separation greedy optimization algorithm interference sensing LEO satellite communication networks signal reconstruction

For Mega-Constellations: Edge Computing and Safety Management Based on Blockchain Technology

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China Communications 2024年第2期21卷 59-73页

作者： zhen Zhang Bing Guo Chengjie li College of Computer Science Sichuan UniversityChengdu 610064China The Key Laboratory for Computer Systems of State Ethnic Affairs Commission School of Computer Science and TechnologySouthwest Minzu UniversityChengdu 610225China National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of ChinaChengdu 611731China

In mega-constellation Communication Systems, efficient routing algorithms and data transmission technologies are employed to ensure fast and reliable data transfer. However, the limited computational resources of satellites necessitate the use of edge computing to enhance secure *** edge computing reduces the burden on cloud computing, it introduces security and reliability challenges in open satellite communication channels. To address these challenges, we propose a blockchain architecture specifically designed for edge computing in mega-constellation communication systems. This architecture narrows down the consensus scope of the blockchain to meet the requirements of edge computing while ensuring comprehensive log storage across the network. Additionally, we introduce a reputation management mechanism for nodes within the blockchain, evaluating their trustworthiness, workload, and efficiency. Nodes with higher reputation scores are selected to participate in tasks and are appropriately incentivized. Simulation results demonstrate that our approach achieves a task result reliability of 95% while improving computational speed.

关键词： blockchain consensus mechanism edge computing mega-constellation reputation management

SAC-Based Computation Offloading for Reconfigurable Intelligent Surface-Aided Mobile Edge Networks

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China Communications 2024年第6期21卷 261-270页

作者： li Bin Qian zhen Fei Zesong School of Computer Science Nanjing University of Information Science&TechnologyNanjing 210044China Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET) Nanjing University of Information Science&TechnologyNanjing 210044 School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China

In this paper,we concentrate on a reconfigurable intelligent surface(RIS)-aided mobile edge computing(MEC)system to improve the offload efficiency with moving user equipments(UEs).We aim to minimize the energy consumption of all UEs by jointly optimizing the discrete phase shift of RIS,UEs’transmitting power,computing resources allocation,and the UEs’task offloading strategies for local computing and *** formulated problem is a sequential decision making across multiple coherent time ***,the mobility of UEs brings uncertainties into the decision-making *** cope with this challenging problem,the deep reinforcement learning-based Soft Actor-Critic(SAC)algorithm is first proposed to effectively optimize the discrete phase of RIS and the UEs’task offloading ***,the transmitting power and computing resource allocation can be determined based on the *** results demonstrate that the proposed algorithm can be trained more stably and perform approximately 14%lower than the deep deterministic policy gradient benchmark in terms of energy consumption.

关键词： MEC RIS soft actor-critic user mobility

Inhibitory effect of schisandrin B on gastric cancer cells in vitro

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World Journal of Gastroenterology 2007年第48期13卷 6506-6511页

作者： Xiao-Ni liu Cheng-Yu Zhang Xiu-dong Jin Yue-zhen li Xue-Zhi zheng li li Department of Physiology Mudanjiang Medical College Mudanjiang 157011 Heilongjiang Province China

AIM： To investigate the inhibitory effect and possible mechanism of action of schisandrin B in SC-B on gastric cancer cells in vitro.METHODS： SC-B consisted of schisandrin B, aloeemodin, and Astragalus polysaccharides. Exponentially growing human gastric cancer SGO7901 cells were divided into six treatment groups：（1） control group （RPMI 1640 medium）; （2） negative control group （2% DMSO）; （3） positive control group （50 mg/L 5-Fluorouracil, 5-FU）; （4） low-dose group （LSC, final concentration of schisandrin B, 25 mg/L）, （5） moderate-dose group （MSC, final concentration of schisandrin B, 50 mg/L）; （6） highdose group （HSC, final concentration of schisandrin B, 100 mg/L）. Follow-up was done at 12-48 h. An MTT （Methylthiazolyldiphenyl-tetrazolium bromide） assay was used to examine the inhibitory effect of SOB on gastric cancer cells. The mitosis index was assessed using an inverted microscope. Flow cytometry was used to visualize the cell cycle. An RT-PCR （Reverse transcription-Polymerase chain reaction） -based assay was used to detect mRNA expression for cyclin D1 and glyceraldehyde-3-phosphate dehydrogenase （GAPDH）.RESULTS： The MTT assay showed that the number of living cells in the LSC, MSC and HSC groups was significantly smaller than that in the DMSO-treated group （P 〈 0.05） at 12-48 h. The inhibitory rate （IR） of the LSC group was 41.15% ± 3.86%, 59.24% ± 5.34% and 69.93% ± 7.81% at 12, 24 and 48 h, respectively. The IR of the MSC group was 42.82% ± 4.94%, 62.68% ± 7.58% and 71.79% ± 8.12% at 12, 24 and 48 h, respectively. The IR of the HSC group was 37.50% ± 3.21%, 40.34% ± 2.98% and 61.99% ± 4.88% at 12, 24 and 48 h, respectively. These results suggested that a moderate dosage had the most obvious inhibitory efficacy at 48 h. Compared to the DMSO group, the mitosis index of the LSC, MSC, HSC groups was greatly decreased （P 〈 0.05） at all time points. Any dose of SC-B suppressed mitosis within 12-48 h. Compared to the DMSO group, the percentage of cells in the

关键词： Aloe-emodin Astragalus polysaccharides Cell cycle Cyclin D1 Gastric cancer Schisandrin B

Improved Approximation Schemes for Early Work Scheduling on Identical Parallel Machines with a Common Due Date

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Journal of the Operations Research Society of China 2024年第2期12卷 341-350页

作者： Wei-dong li School of Mathematics and Statistics Yunnan UniversityKunming650504YunnanChina

We study the early work scheduling problem on identical parallel machines in order to maximize the total early work,i.e.,the parts of non-preemptive jobs that are executed before a common due *** preprocessing and constructing an auxiliary instance which has several good properties,for any desired accuracy,we propose an efficient polynomial time approximation scheme with running time O(f(1/ε)n),where n is the number of jobs and f(1/ε)is exponential in 1/ε,and a fully polynomial time approximation scheme with running time O(1/ε^(2m+1)+n)when the number of machines is fixed.

关键词： Scheduling Early work Polynomial time approximation scheme Effcient polynomial time approximation scheme Fully polynomial time approximation scheme

Molecular Chain Flexibility and Dielectric Loss at High-Frequency:Impact of Ester Bond Arrangement in Poly(ester imide)s

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Chinese Journal of Polymer Science 2024年第8期42卷 1122-1133页

作者： Ya-dong li Hong li Lu-Kun Feng Feng Bao Ming-liang Wang Cai-zhen Zhu Zhao-Hui zheng Xiao-Bin Ding Jian Xu Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100081China Institute of Low-Dimensional Materials Genome Initiative College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China

The evolution of high-frequency communication has accentuated the significance of controlling dielectric properties in polymer ***,it has been theorized that rigid molecular chains lead to lower dielectric ***,the validity of this proposition at high frequencies remains *** scrutinize the correlation between chain flexibility and dielectric properties,we synthesized six poly(ester imide)s(PEIs)with systematically varied molecular chain flexibilities by modifying the ester's substitution on the aromatic *** introduction of ester bonds bestowed all PEI films with a low dielectric dissipation factor(D_(f)),ranging from 0.0021 to 0.0038 at 10 GHz in dry *** dry D_(f)displayed a pattern consistent with volume polarizability(P/V).Unexpectedly,PI-mmm-T,featu ring the most flexible molecular chain,exhibited the lowest dielectric loss under both dry(0.0021@10 GHz)and hygroscopic(0.0029@10 GHz)***,the observed increase in D_(f)after humidity absorption suggests that the high dielectric loss of PEI in applications may be attributed to its hygroscopic *** simulations and characterization of the aggregation structure revealed that the smaller cavities within flexible molecular chains,after close stacking,impede the entry of water *** sacrificing high-temperature resistance,the precursor exhibited enhanced solubility properties and could be processed into high-quality *** research unveils new insights into the relationship between flexibility and highfrequency dielectric loss,offering innovative perspectives on synthesizing aromatic polymers with exceptional dielectric properties.

关键词： 5G communications Poly(ester imide)s Molecular chain flexibility Dielectric properties Humidity absorption

A state-of-the-art review of the development of self-healing concrete for resilient infrastructure

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 151-169页

作者： dong LU Xi JIANG Yao ZHANG Shaowei ZHANG Guoyang LU zhen LENG Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China Laboratory of Fire Safety School of Safety Engineering and Emergency ManagementShijiazhuang Tiedao UniversityShijiazhuang 050043China Department of Architecture and Civil Engineering City University of Hong KongHong Kong 999077China

The brittleness of cement composites makes cracks almost inevitable,producing a serious limitation on the lifespan,resilience,and safety of concrete *** address this brittleness,self-healing concrete has been developed for regaining its mechanical and durability properties after becoming cracked,thereby promising sustainable development of concrete *** paper provides a comprehensive review of the latest developments in self-healing *** begins by summarizing the methods used to evaluate the self-healing efficiency of ***,it compares strategies for achieving healing *** then discusses the typical approaches for developing self-healing ***,critical insights are proposed to guide future studies on the development of novel self-healing *** review will be useful for researchers and practitioners interested in the field of self-healing concrete and its potential to improve the durability,resilience,and safety of concrete infrastructure.

关键词： resilient infrastructure sustainable concrete self-healing cracks