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Probabilistic Control Volume Method for Evaluating the Effects of Notch Size and Loading Type on Fatigue Life

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Acta Mechanica Solida Sinica 2020年第2期33卷 141-149页

作者： Chunming Li Zheng Hu Chengqi Sun Qingyuan song Wanhao Zhang China North Vehicle Research Institute Beijing 100072China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China

The probabilistic control volume method has great prospects in correlating the effects of specimen size,notch and loading type on fatigue life or fatigue *** this work,the effects of notch size and loading type on fatigue life are investigated by using the probabilistic control volume *** bending and axial loading fatigue te«t«are at first performed on the hourglass specimen,circumferential V-notch specimen and V-notch plate specimen of 30CrMnSiA *** results indicate that the notch reduces the fatigue strength of specimens in terms of nominal stress amplitude while in terms of local stress amplitude,the notch specimen could endure higher fatigue ***,the probabilistic control volume method is used to evaluate the effects of notch size and loading type on fatigue *** is shown that the probabilistic control volume method correlates well the effects of notch size and loading type on fatigue life,even for the local stress of the notch root exceeding the yield stress of the material.

关键词： 30CrMnSiA steel Notch size Loading type Fatigue life Control volume method

Unraveling the threshold stress of structural rejuvenation of metallic glasses via thermo-mechanical creep

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Science China(Physics,Mechanics & Astronomy) 2022年第6期65卷 101-109页

作者： Gan Ding Feng Jiang Xuan song LanHong Dai MinQiang Jiang State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

The competition between physical aging and structural rejuvenation determines the physical and mechanical properties of glassy ***,the rejuvenation-aging boundary must be identified *** this work,we unravel a stress boundary to distinguish rejuvenation from aging via the thermo-mechanical creep of a typical Zr-based metallic *** crept glasses were rejuvenated into high-enthalpy disordered states when the applied stress exceeded a threshold that was numerically close to the steady-state flow stress;otherwise,the glasses were aged.A theoretical model for glass creep was adopted to demystify the observed stress threshold of *** model revealed that the thermo-mechanical creep beyond the threshold stress could activate sufficient shear transformations to create a net free volume,thus leading to structural ***,we derived the analytical expressions for the threshold and flow *** stresses can act as the rejuvenation-aging boundary,which is well supported by experimental creep *** present work procures a deeper understanding of the rejuvenation mechanism of glasses and provides useful implications for abstaining from glass aging.

关键词： metallic glass thermo-mechanical creep threshold stress shear transformations rejuvenation-aging boundary

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Aeroacoustic and aerodynamic optimization of propeller blades

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Chinese Journal of Aeronautics 2020年第3期33卷 826-839页

作者： Peixun YU Jiahui PENG Junqiang BAI Xiao HAN Xiang song School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Unmanned System Research Institute Northwestern Polytechnical UniversityXi’an 710072China

It is of great significance to develop a high-efficiency and low-noise propeller optimization method for new-generation propeller aircraft *** with free form deformation method,dynamic mesh interpolation technology,optimization algorithm,surrogate model,aerodynamic calculation and aeroacoustic prediction model module,the integrated aerodynamic and aeroacoustic design method of propeller is *** optimization design for the six-blade propeller is carried *** non-reduction in efficiency,thrust coefficient and the minimum of aerodynamic noise is treated as the optimization design *** spatial vorticity distribution of the propeller before and after the design is also analyzed by using unsteady computational fluid dynamics *** results show that the optimized propeller can effectively reduce the aerodynamic noise *** maximum total sound pressure level can be reduced by 5 dB without reducing its aerodynamic *** developed method has good application potential in low-noise optimization design of propeller and other rotating machinery.

关键词： Aeroacoustic Aerodynamic Dynamic mesh interpolation technology Free form deformation method Optimization algorithm Propeller Sound pressure level Surrogate model

Constructing graphene nanosheet-supported FeOOH nanodots for hydrogen storage of MgH2

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International Journal of Minerals,Metallurgy and Materials 2022年第7期29卷 1464-1473页

作者： Mengchen song Liuting Zhang Jiaguang Zheng Zidong Yu Shengnan Wang School of Energy and Power Jiangsu University of Science and TechnologyZhenjiang 212003China Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621999China

Novel graphene-supported FeOOH nanodots(FeOOH NDs@G)were successfully prepared by a facile hydrothermal method and doped into MgH_(2)through mechanical ***_(2)with 10wt%FeOOH NDs@G began to release hydrogen at 229.8℃,which is106.8℃ lower than that of pure MgH_(2).The MgH_(2)-10wt%FeOOH NDs@G composite could reversibly absorb 6.0wt%hydrogen at 200℃ under a 3.2 MPa hydrogen pressure within 60 *** the addition of FeOOH NDs@G,the dehydrogenation and hydrogenation activation energy of MgH_(2)was decreased to 125.03 and 58.20 kJ·mol^(-1)(156.05 and 82.80 kJ·mol^(-1)for pure MgH_(2)),***,the hydrogen capacity of the FeOOH NDs@G composite retained 98.5%of the initial capacity after 20 cycles,showing good cyclic *** catalytic action of FeOOH NDs@G towards MgH_(2)could be attributed to the synergistic effect between graphene nanosheets and in-situ formed Fe,which prevented the aggregation of Mg/MgH2 particles and accelerated the hydrogen diffusion during cycling,thus enabling the Mg H_(2)-10wt%FeOOH NDs@G composite to exhibit excellent hydrogen storage performance.

关键词： hydrogen storage MgH_(2) FeOOH NDs@G catalysis

Novel broad spectral response perovskite solar cells:A review of the current status and advanced strategies for breaking the theoretical limit efficiency

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Journal of Materials Science & Technology 2023年第9期140卷 33-57页

作者： Bin Liu Yuqi Wang Yanjie Wu Biao Dong Hongwei song State Key Laboratory on Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

Perovskite solar cells(PSCs)have revolutionized photovoltaic *** power conversion efficiency(PCE)of PSCs has now reached 25.7%,which is comparable to current state-of-the-art silicon-based ***,PSCs can only utilize light of 300-850 nm,resulting in wasted near-infrared(NIR)light,which occupies 45%-50%of entire solar spectrum,which is one of the main reasons limiting the development of *** strategies to broaden NIR spectroscopy to break the theoretical limit efficiency of PSCs have recently attracted extensive *** review firstly outlines theoretical basis for improving the NIR spectroscopy,then systematically summarizes some key strategies and research progress to improve NIR spectroscopy of *** firstly provided a comprehensive overview of historical research experiments on narrow-gap perovskite absorber layers,rare earth up-conversion,tandem devices,and integrated perovskite/organic solar cells and given constructive suggestions for exceeding limit efficiency of ***,based on the development status of PSCs with NIR utilization,the current issues,solutions and future development directions of important aspects to improve NIR utilization of PSCs are systematically *** review lays the foundation for the efficiency of PSCs beyond the Shockley-Queisser limit,and provides a certain development prospect.

关键词： Organic materials Up-conversion materials Perovskite solar cells Tandem cells Integrated perovskite/organic heterojunction solar cells

Research Advances on AI-Powered Thermal Management for Data Centers

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Tsinghua Science and Technology 2022年第2期27卷 303-314页

作者： Hui Liu AbdusSalam Aljbri Jie song Jinqing Jiang Chun Hua the School of Metallurgy Northeastern UniversityShenyang 110819China the Software College Northeastern UniversityShenyang 110169China the College of Computer Science and Technology Inner Mongolia University for NationalitiesTongliao 010021China

Given the complex nature of data centers’thermal management,which costs too many resources,processing time,and energy consumption,thermal awareness and thermal management powered by artificial intelligence(AI)are the targeted *** addition to a few research on AI techniques and models,other strategies have also been introduced in recent *** center models,including cooling,thermal,power,and workload models,and their relationship are factors that need to be understood in the optimal thermal management *** approaches have been proposed to help validate new models or methods used for scheduling and consolidating processes and virtual machines(VMs),hotspot identification,thermal state estimation,and power usage ***-powered thermal optimization leads to improved process scheduling and consolidation of VMs and eliminates the hotspot from *** present,research on AI-powered thermal control is still in its *** paper concludes with four issues in thermal management,which will be the scope of further research.

关键词： data center thermal management artificial intelligence heuristic metaheuristic

Intervalence charge transfer of Cr^(3+)-Cr^(3+) aggregation for NIR-Ⅱ luminescence

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Light(Science & Applications) 2023年第8期12卷 1686-1695页

作者： Shengqiang Liu Jingxuan Du Zhen song Chonggeng Ma Quanlin Liu Beijing Municipal Key Laboratory of New Energy Materials and Technologies School of Materials Sciences and EngineeringUniversity of Science and Technology BeijingBeijing 100083China School of Optoelectronic Engineering&CQUPT-BUL Innovation Institute Chongqing University of Posts and TelecommunicationsChongqing 400065China

The increasing demand for high-contrast biological imaging,non-destructive testing,and infrared night vision can be addressed by the development of high-performance NIR light-emitting *** lanthanide(Ln^(3+))with sharp-line multiplets and isolated Cr^(3+)with NIR-I emission,this study reports the first-ever NIR-Ⅱ broadband luminescence based on the intervalence charge transfer(IVCT)of Cr^(3+)-Cr^(3+)aggregation in gallate *** particular,LaMgGa11O19:0.7Cr^(3+)exhibits dual-emission(NIR-I,890 nm and NIR-Ⅱ,1200 nm)with a full width at half maximum(FWHM)of 626 nm under 450 nm blue LED ***,this dual-emission exhibits anti-thermal quenching behavior(432%@290 K),attributed to the energy transfer among multiple Cr^(3+)*** absorption spectra,lifetimes decay(2.3 ms),and electron paramagnetic experiments reveal the NIR-Ⅱ luminescence of the Cr^(3+)-Cr^(3+)→Cr^(2+)-Cr^(4+)IVCT *** application of LaMgGa_(11)O_(19)∶0.7Cr^(3+)in NIR-Ⅱ biological imaging as an optical contrast agent,non-destructive testing,and night vision is *** work provides new insights into broadband NIR-Ⅱ luminescence under UV-NIR excitation based on the IVCT of Cr^(3+)-Cr^(3+)aggregation.

关键词： transition. materials. luminescence

Antitumor effects of mutant endostatin are enhanced by Bcl-2 antisense oligonucleotides in UM-UC-3 bladder cancer cell line

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Chinese Medical Journal 2013年第15期126卷 2834-2839页

作者： REN Ming-hua YU Jing-song song Er-lin ZHANG Cheng MA Li JIAO zhi-xing ZHAO Wei-ming SHAN Yu-juan NI Shao-bin Harbin Med Univ Affiliated Hosp 1 Dept Urinary Surg Harbin 150001 Heilongjiang Peoples R China Chinese Peoples Liberat Army Hosp 211 Dept Urinary Surg Harbin 150080 Heilongjiang Peoples R China Harbin Inst Technol Food Sci & Engn Sch Harbin 150090 Heilongjiang Peoples R China

Background Endostatin is a potent inhibitor of tumor angiogenesis. In the preliminary studies, we developed a mutant endostatin containing Arg-Gly-Asp-Arg-Gly-Asp （RGDRGD） sequences. In this study, we compared the antitumor effects of mutant endostatin and Bcl-2 antisense oligonucleotides both in combination and individually. Methods The artificially synthesized Bcl-2 ASODN （antisense oligonucleotides） included a translation-initiation site and was transfected into the bladder cancer cells by Lipofectamine. Cell growth was investigated by the tumor cell growth chart, MTT assay, caspase-3 activity detection assay, AO/EB fluorescein stain, and the annexin V-FITC apoptosis detection assay. In the in vivo study, UM-UC-3 bladder cancer cells were subcutaneously implanted into nude mice and the growth of tumor was examined. The ultrastructure of the tumor tissues in the treated and control groups were observed. Results The cell growth chart showed that the cell population of the treated combination group decreased by 52.04% compared to the control group. The inhibition rate of the treated combination group was （79.66＋6.79）%, whereas those of the individual ASODN and ES groups were （53.39＋3.22）% and （50.22＋5.46）% respectively. In the caspase-3 activity detection using AO/EB fluorescein stain and annexin V-FITC apoptosis detection assay, the co-inhibitory effect was higher than the individual inhibitory effects （P〈0.05）. There were significant differences in the inhibition of the solid tumor growth in the in vivo study. Conclusions Our findings indicated that Bcl-2 antisense oligonucleotides enhance the antitumor effects of mutant endostatin both in vitro and in vivo. We noted the synergistic effects of Bcl-2 antisense oligonucleotides combined with mutant endostatin.

关键词： endostatin Bcl-2 antisense oligonucleotides Arg-Gly-Asp

A model predictive control strategy with switching cost functions for cooperative operation of trains

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Science China(Information Sciences) 2023年第7期66卷 224-236页

作者： Zixuan ZHANG Haifeng song Hongwei WANG Ling LIU Hairong DONG State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University School of Electronic and Information Engineering Beihang University Beijing National Railway Research and Design Institute of Signal and Communication

The cooperative control of trains is proposed as an innovative method for further improving operation efficiency. Model predictive control(MPC) has been widely discussed for multiple trains because it can handle the challenges posed by the cooperative control problem, such as complex constraints. In real situations, multiple objectives, such as comfort and safety, must be considered when controlling multiple trains with MPC, and the total objective may change during operation, affecting control performance. In this paper, a distributed structure based on switching cost function model predictive control(ScMPC) for multiple trains in a switching situation is given, where the cost functions of the train control problem change with the variable demand of cooperative operation. Furthermore, the feasibility of the proposed method and stability of the closed-loop system are proved to guarantee the stable operation of the controlled ***, the control method’s effectiveness is verified. Three kinds of cost functions are given, and their control performance is compared to show the effect of different weights and the advantage of ScMPC.

关键词： cooperative control switching cost functions model predictive control automatic train operation railway train