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New formula for predicting the plastic buckling pressure of steel torispherical heads under internal pressure

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第8期25卷 618-630页

作者： Sheng YE Keming li Jinyang ZHENG shan SUN Institute of Process Equipment Zhejiang UniversityHangzhou 310027China Engineering Research Center for High Pressure Process Equipment and Safety of Ministry of Education Hangzhou 310027China State Key Laboratory of Fluid Power and Mechatronic Systems Hangzhou 310058China

Thin-walled torispherical heads under internal pressure can fail by plastic buckling because of compressive circumferential stresses in the head ***,existing formulas still have limitations,such as complicated expressions and low accuracy,in determining buckling *** this paper,we propose a new formula for calculating the buckling pressure of torispherical heads based on elastic-plastic analysis and experimental ***,a finite element(FE)method based on the arc-length method is established to calculate the plastic buckling pressure of torispherical heads,considering the effects of material strain hardening and geometrical *** buckling pressure results calculated by the FE method in this paper have good consistency with those of BOSOR5,which is a program for calculating the elastic-plastic bifurcation buckling pressure based on the finite difference energy ***,the effects of geometric parameters,material parameters,and restraint form of head edge on buckling pressure are ***,a new formula for calculating plastic buckling pressure is developed by fitting the curve of FE results and introducing a reduction factor determined from experimental ***,based on the experimental results,we compare the predictions of the new formula with those of existing *** is shown that the new formula has a higher accuracy than the existing ones.

关键词： Torispherical head Plastic buckling Elastic-plastic analysis Prediction formula Finite element method

Influence of ammonium sulfate on the corrosion behavior of AZ31 magnesium alloy in chloride environment

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Journal of Magnesium and Alloys 2024年第3期12卷 1082-1101页

作者： Feng Ge Zhongyu cui Yue liu li Lei Xin Wang Hongzhi cui School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China Beijing National Innovation Institute of lightweight Ltd.Beijing 101499China

Electrochemical corrosion of AZ31 magnesium alloy in the NH_(4)^(+)-SO_(4)2−-Cl−environment is *** of NH_(4)^(+)overshadows that of Cl−as the(NH_(4))_(2)SO_(4) concentration is 0.005 M or higher,yielding an evolution from localized corrosion to uniform *** effect of NH_(4)^(+)can be attributed to that(i)NH_(4)^(+)dissolves the inner MgO and hinders the precipitation of Mg(OH)_(2) and(ii)the buffering ability of NH_(4)^(+)provides H+,enhances the hydrogen evolution,and expedites the corrosion *** latter is demonstrated as the dominant factor with the results in unbuffered and buffered *** severe corrosion and hydrogen process in NH_(4)^(+)-containing solution results in a high Hads coverage and yields an inductive loop within the low ***,SO_(4)^(2−)is helpful in generating cracked but partially protective corrosion products,while Cl−could broaden the corrosion area beneath the corrosion product.

关键词： Magnesium alloy Ammonium corrosion Electrochemical kinetic parameter Anodic dissolution.

Fault diagnosis of a marine power-generation diesel engine based on the Gramian angular field and a convolutional neural network

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 470-482页

作者： Congyue li Yihuai HU Jiawei JIANG Dexin cui Merchant Marine College Shanghai Maritime UniversityShanghai 201306China School of Mechanical and Energy Engineering Shanghai Technical Institute of Electronics&InformationShanghai 201411China

Marine power-generation diesel engines operate in harsh *** vibration signals are highly complex and the feature information exhibits a non-linear *** is difficult to extract effective feature information from the network model,resulting in low fault-diagnosis *** address this problem,we propose a fault-diagnosis method that combines the Gramian angular field(GAF)with a convolutional neural network(CNN).Firstly,the vibration signals are transformed into 2D images by taking advantage of the GAF,which preserves the temporal *** raw signals can be mapped to 2D image features such as texture and *** integrate the feature information,the images of the Gramian angular summation field(GASF)and Gramian angular difference field(GADF)are fused by the weighted average fusion ***,the channel attention mechanism and temporal attention mechanism are introduced in the CNN model to optimize the CNN learning *** the concept of residuals in the attention mechanism improves the feasibility of ***,the weighted average fused images are fed into the CNN for feature extraction and fault *** validity of the proposed method is verified by experiments with abnormal valve *** average diagnostic accuracy is 98.40%.When−20 dB≤signal-to-noise ratio(SNR)≤20 dB,the diagnostic accuracy of the proposed method is higher than 94.00%.The proposed method has superior diagnostic ***,it has a certain anti-noise capability and variable-load adaptive capability.

关键词： Multi-attention mechanisms(MAM) Convolutional neural network(CNN) Gramian angular field(GAF) Image fusion Marine power-generation diesel engine Fault diagnosis

OIP5 Interacts with NCK2 to Mediate Human Spermatogonial Stem Cell Self-Renewal and Apoptosis through Cell Cyclins and Cycle Progression and Its Abnormality Is Correlated with Male Infertility

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Research 2024年第1期2023卷 455-469页

作者： Yinghong cui Wei Chen li Du Zuping He The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province The Research Center of Reproduction and Translational Medicine of Hunan ProvinceHunan Normal University School of MedicineChangsha 410013HunanChina

Spermatogonial stem cells(SSCs)have important applications in both reproduction and regenerative ***,specific genes and signaling transduction pathways in mediating fate decisions of human SSCs remain ***,we have demonstrated for the first time that OIP5(Opa interacting protein 5)controlled the self-renewal and apoptosis of human *** sequencing identified that NCK2 was a target for OIP5 in human SSCs,and interestingly,OIP5 could interact with NCK2 as shown by Co-IP(co-immunoprecipitation),IP-MS(mass spectrometry),and GST pulldown ***2 silencing decreased human SSC proliferation and DNA synthesis but enhanced their ***,NCK2 knockdown reversed the influence of OIP5 overexpression on human ***,OIP5 inhibition decreased the numbers of human SSCs at S and G2/M phases,while the levels of numerous cell cycle proteins,including cyclins A2,B1,D1,E1 and H,especially cyclin D1,were remarkably ***,whole-exome sequencing of 777 patients with nonobstructive azoospermia(NOA)revealed 54 singlenucleotide polymorphism mutations of the OIP5 gene(6.95%),while the level of OIP5 protein was obviously lower in testes of NOA patients compared to fertile ***,these results implicate that OIP5 interacts with NCK2 to modulate human SSC self-renewal and apoptosis via cell cyclins and cell cycle progression and that its mutation and/or lower expression is correlated with *** such,this study offers novel insights into molecular mechanisms underlying the fate determinations of human SSCs and the pathogenesis of NOA,and it provides new targets for treating male infertility.

关键词： OIP5 Apoptosis reversed

Vibration harmonic suppression technology for electromagnetic vibrators based on an improved sensorless feedback control method

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Frontiers of Information Technology & Electronic Engineering 2024年第3期25卷 472-483页

作者： Wei li Junning cui Xingyuan BIAN limin ZOU Centerof Ultra-precision Optoelectronic Instrument Engineering Harbin Institute of TechnoogyHarbin 0080China Key Lab of Ultra-precision Intlligent Instrumentation(Harbin Institute of Technology).Ministry of Industry and Information Technology Harbin 150080China

To realize low harmonic distortion of the vibration waveform output from electromagnetic vibrators,we propose a vibration harmonic suppression technology based on an improved sensorless feedback control *** changing the original driving circuit,the alternating current(AC)equivalent resistance of the driving coil is used to obtain high-precision vibration velocity information,and then a simple and reliable velocity feedback control system is *** the study of the effect of different values of key parameters on the system,we have achieved an effective expansion of the velocity characteristic frequency band of low-frequency vibration,resulting in an enhanced harmonic suppression capability of velocity feedback *** present extensive experiments to prove the effectiveness of the proposed method and make comparisons with conventional control *** the frequency range of 0.01-1.00 Hz,without using any sensors,the method proposed in this study can reduce the harmonic distortion of the vibration waveform by about 40%compared to open-loop control and by about 20%compared to a conventional sensorless feedback control method.

关键词： Vibration calibration Electromagnetic vibrators Harmonic suppression Sensorless control method Velocity feedback control

Distributed user pairing and effective computation offloading in aerial edge networks

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Chinese Journal of Aeronautics 2024年第4期37卷 378-390页

作者： Wei liANG Shuhui WEN lixin li Jingjing cui School of Electronics and Information Northwestern Polytechnical UniversityXi’an CN710072China The State Key Laboratory of Integrated Services Networks Xidian UniversityXi’an CN710126China School of Electronics and Computer Science University of SouthamptonSouthampton SO167NSUK

Future Sixth-Generation (6G) mobile communication networks extremely require the global connectivity and the ground Base Stations (BSs) are difficult to develop in some specific areas,such as mountainous ***,the aerial networks are the key framework for the future communications,in which the aerial vehicle could act as the access ***,Mobile Edge Computing (MEC) is also essential to enhance the data processing capabilities of aerial *** this paper,we study a comprehensive communication-computation resource management problem for jointly optimizing user pairing,power and time allocation in the MEC aided Cognitive Radio (CR) aerial networks,namely CR-MEC aerial ***,this multilevel optimization problem could be decomposed into the user pairing and power allocation as well as time allocation *** the conceived CR-MEC aerial networks,we propose a User Pairing and Computation Offloading Management Algorithm (UPCOMA) based on three-sided matching theory,aiming to minimize the system’s energy *** the first step of UPCOMA,multiple Primary Users (PUs) and Cognitive Users (CUs) on the ground negotiate to each other with the suitable power allocation coefficients and construct the stable user ***,the stable user pairs would match to a high altitude platform who act as the base station,which is for appropriately allocating Transmission Time Slots (TSs) at the second step of ***,a hybrid offloading mode is proposed in our conceived networks in order to support ground users to offload their tasks adaptively according to their individual ***,the simulation results reveal that the relative performance of UPCOMA is close to that of the Brute-Force Search Algorithm (BFSA) with low ***,the hybrid offloading mode with less energy consumption supports much more ground user pairs to offload tasks compared to the binary mode.

关键词： Aerial edge computing Binary offloading Cognitive radio Hybrid offloading Resource management

Microlensing bias on the detection of strong lensing gravitational wave

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 156-165页

作者： Xikai shan Xuechun Chen Bin Hu Guoliang li Institute for Frontier in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Department of Astronomy Beijing Normal UniversityBeijing 100875China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China

Identifying strong lensing gravitational wave(SLGW)events is of utmost importance in astrophysics as we approach the historic first detection of SLGW amidst the growing number of gravitational wave(GW)***,one crucial method for identifying SLGW signals involves assessing the overlap of parameters between two ***,the distribution of discrete matter,such as stars and sub-halos,within the strong lensing galaxy can imprint a wave optical(WO)effect on the SLGW *** frequency dependent imprints introduce biases in parameter estimation and impact SLGW *** this study,we assess the influence of the stellar microlensing field embedded in a strong lensing *** findings demonstrate that the WO effect reduces the detection efficiency of SLGW by 5%-50%for various false alarm probabilities per pair(FAPper pair).Specifically,at an FAPper pairof 10^(-5),the detection efficiency decreases from~10%to~5%.Consequently,the presence of the microlensing field can result in missing half of the strong lensing ***,the microlensing WO effect introduces a noticeable bias in intrinsic parameters,particularly for chirp mass and mass ***,it has tiny influence on extrinsic *** all parameters,~30%of events exhibit a 1σparameter bias,~12%exhibit a 2σparameter bias,and~5%exhibit a 3σparameter bias.

关键词： gravitational wave gravitational strong lensing gravitational micro lensing wave optical effect

Experimental investigation of spectral evolution in flash radiation by hypervelocity impact on aluminum plates

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Defence Technology（防务技术） 2024年第7期37卷 96-110页

作者： Xing Chen Yonggang Lu Zhiwen li Zhonghua cui Institute of Systems Engineering China Academy of Engineering PhysicsMianyang 621900SichuanChina Chongqing Qianwei Technology Group Co. LtdChongqing 401121China

In this study,a series of hypervelocity impact tests were carried out based on a two-stage light gas gun,and the sequence spectrum and radiation evolution data of the impact products under different impact conditions were *** diameter of the projectile is 3-5 mm,the impact velocity is 3.13-6.58 km/s,and the chamber pressure is 0.56-990 *** spectrum of ejected debris cloud in the 250-310 nm band were obtained using a transient spectral measurement system and a multi-channel radiometer measurement *** test results reveal that the flash radiation intensity increases as a power function with the kinetic energy of the ***,the peak value of the line spectrum decreases as the chamber vacuum degree increases,while the radiation width gradually *** line spectrum in the spectral characterization curve corresponds to the ejected debris clouds splitting phase,which does not produce significant line spectrum during material fragmentation and is dominated by the continuum spectrum produced by blackbody *** will appear one or three characteristic peaks in the flash radiation time curve,the first and second peaks correspond to the penetration phase and the third peak corresponds to the expansion phase of the ejected debris clouds on the time scale,the first and second peaks are more sensitive to the chamber vacuum degree,and when the pressure is higher than 99 Pa,the first and second characteristic peaks will *** radiant heat attenuation of the flash under different impact conditions is significantly different,the attenuation exponent has a power function relationship with the impact velocity and the chamber vacuum degree,while the attenuation exponent has a linear relationship with the diameter of the projectile,the specific expression of the attenuation exponent is obtained by *** findings from this research can serve as a valuable reference for remote diagnostic technologies based on flash radiation characte

关键词： Hypervelocity impact Flash radiation Evolution Spectral characteristics Damage evaluation

Facet effects on bimetallic ZnSn hydroxide microcrystals for selective electrochemical CO2 reduction

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Green Energy & Environment 2024年第8期9卷 1314-1320页

作者： liu Han Cheng-wei Wang shan-shan Luo Ying-tang Zhou Bing li Ming liu School of Chemistry and Chemical Engineering Harbin Institute of Technology National Engineering Research Center for Marine Aquaculture Marine Science and Technology CollegeZhejiang Ocean University

Employing crystal facets to regulate the catalytic properties in electrocatalytic carbon dioxide reduction reaction（eCO2RR） has been well demonstrated on electrocatalysts containing single metals but rarely explored for bimetallic systems. Here, we synthesize Zn Sn（OH）6（ZSO）microcrystals（MCs） with distinct facets and investigate the facet effects in eCO2RR. Electrochemical studies and in situ Fourier Transform Infrared Spectroscopy（in situ-FTIR） reveal that ZSO MCs produce mainly C1 products of HCOOH and CO. The {111} facet of the ZSO MCS exhibits higher selectivity and faradaic efficiency（FE） than that of the {100} facet over a wide range of potentials（-0.9 V ～-1.3 V versus RHE）. Density Functional Theory（DFT） calculations elucidate that the {111} facet is favorable to the adsorption/activation of CO2molecules,the formation of intermediate in the rate-determining step, and the desorption of C1 products of CO and HCOOH molecules.

关键词： ZnSn(OH) 6 Crystal facets Electrochemical carbon dioxide reduction C1 product Density functional theory