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Detection and analysis of magnetic particle testing defects on heavy truck crankshaft manufactured by microalloyed medium-carbon forging steel

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Journal of Iron and Steel Research International 2020年第5期27卷 608-616页

作者： Jin-long Lu Guo-guang cheng meng Wu Guo Yang Ju-long Che State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Research and Development Department Xining Special Steel Co.Ltd.Xining 810005QinghaiChina

An unqualifed six-cylinder heavy truck crankshaft has been studied to investigate the cause of magnetic particle testing defects on the rod ***-sized long-striped MnS inclusions are regarded as the major cause for the magnetic particle testing failure because they have been detected in situ under the magnetic particle *** the observation of macroscopic structures of the rod journals and corresponding counterweight blocks,it is found that for the 1#and 3#rod journals,the center metal of the original hot-rolled bar has been extruded to the inboard edge of the rod journals and large-sized long-striped MnS inclusions are exposed on the surface after fash removal,leading to the failure of magnetic particle *** for the 2#rod journal,the center metal of the original bar has not been extruded to the surface and MnS inclusions on the rod journal surface are small in size,few in number,resulting in passing the magnetic particle *** the quality of the hot-rolled bars fuctuates,it is more recommended to apply magnetic particle testing on samples at the center of bars before forging to evaluate the severity of defects caused by the long-striped MnS inclusions for fear of the scrap of the fnal crankshafts.

关键词： Crankshaft Magnetic particle testing MnS inclusion Microalloyed medium-carbon forging steel Defect

Impact of Coastal Radar Observability on the Forecast of the Track and Rainfall of Typhoon Morakot(2009)Using WRF-based Ensemble Kalman Filter Data Assimilation

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Advances in Atmospheric Sciences 2017年第1期34卷 66-78页

作者： jian YUE Zhiyong meng cheng-Ku YU Lin-Wen cheng Laboratory for Climate and Ocean–Atmosphere Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking University Department of Atmospheric Sciences NTU

This study explored the impact of coastal radar observability on the forecast of the track and rainfall of Typhoon Morakot （2009） using a WRF-based ensemble Kalman filter （EnKF） data assimilation （DA） system. The results showed that the performance of radar EnKF DA was quite sensitive to the number of radars being assimilated and the DA timing relative to the landfall of the tropical cyclone （TC）. It was found that assimilating radial velocity （Vr） data from all the four operational radars during the 6 h immediately before TC landfall was quite important for the track and rainfall forecasts after the TC made landfall. The TC track forecast error could be decreased by about 43% and the 24-h rainfall forecast skill could be almost tripled. Assimilating Vr data from a single radar outperformed the experiment without DA, though with less improvement compared to the multiple-radar DA experiment. Different forecast performances were obtained by assimilating different radars, which was closely related to the first-time wind analysis increment, the location of moisture transport, the quasi-stationary rainband, and the local convergence line. However, only assimilating Vr data when the TC was farther away from making landfall might worsen TC track and rainfall forecasts. Besides, this work also demonstrated that Vr data from multiple radars, instead of a single radar, should be used for verification to obtain a more reliable assessment of the EnKF performance.

关键词： radial velocity ensemble Kalman filter observability tropical cyclone track rainfall

On the Growth of Solutions of Second Order Linear Differential Equations with Extremal Coefficients

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Acta Mathematica Sinica,English Series 2013年第2期29卷 365-372页

作者： jian Ren long Peng cheng WU Zheng ZHANG School of Mathematics and Computer Science Guizhou Normal University

In this paper, we consider the differential equation f＂＋ A（z）f＇＋ B（z）f = 0, where A and B= 0 are entire functions. Assume that A is extremal for Yang＇s inequality, then we will give some conditions on B whi... 详细信息

关键词： Entire function deficient value Borel direction order

Satellite remote sensing of volcanic ash cloud in complicated meteorological conditions

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Science China Earth Sciences 2011年第11期54卷 1789-1795页

作者： ZHU Lin LIU jian LIU cheng WANG meng National Satellite Meteorological Center of China Meteorological Administration Beijing 100081 China

Volcanic ash cloud has serious impacts on *** volcanic ash dispersion,it also has a profound and long-term impact on climate and the environment.A new volcanic ash cloud detecting method (SWIR-TIR Volcanic Ash method,STVA) is presented that uses satellite images of Medium Resolution Spectral Imager (MERSI) and Visible and Infrared Radiometer (VIRR) on board the second generation Polar-Orbiting meteorological satellite of China (FY-3A).STVA is applied in detecting Iceland's Eyjafjallajokull volcano *** with the traditional Split Window Temperature Difference method (SWTD),the results show that STVA is more sensitive to volcanic ash cloud than SWTD and can fairly extract volcanic ash information from the background of meteorological cloud and the *** Radiance Index (ARI) and Absorbing Aerosol Index (AAI) derived from Metop-A satellite images are used to validate the performance of *** is shown that STVA provides similar results with ARI and ***-3A/MERSI,VIRR and Terra /MODIS data are used to test STVA and *** is demonstrated that STVA derived from FY-3A satellite data is more effective in complicated meteorological *** study shows great potential of using China's own new generation satellite data in future global volcanic ash cloud monitoring operation.

关键词： FY-3A/MERSI FY-3A/VIRR volcanic ash cloud Split Window Temperature Difference method SWIR-TIR VolcanicAsh method

Bore-center annular shaped charges with different liner materials penetrating into steel targets

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Defence Technology（防务技术） 2019年第5期15卷 796-801页

作者： Wen-long Xu cheng Wang jian-ming Yuan Tao Deng State Key Lab of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Temasek Laboratories Nanyang Technological University50 Nanyang Drive637553Singapore

The bore-center annular shaped charge(BCASC)is a new type of shaped charge which can generate a larger-diameter hole in steel targets than classical shaped *** this paper,the influence of three liner materials,***,nickel and copper,on BCASC formation and penetrating into steel targets was investigated by experiment and numerical *** simulation results were well consistent with the experimental *** study showed that,at 0.50D standoff distance,the axial velocity of the molybdenum projectile was lower than that of the nickel and copper *** nickel and copper projectiles had almost the same head *** absolute values of the radial velocity of the molybdenum projectile head was lower than that of the nickel and copper ***,at 0.75D standoff distance,the absolute values of the radial velocity of the molybdenum projectile head became much greater than that of the nickel and copper projectile *** projectile formed by BCASC with the molybdenum liner had the highest penetration depth of 61.5 mm,which was 10.0%and 21.3%higher than that generated by the copper and nickel projectiles.

关键词： Annular shaped charge Liner material Formation Numerical simulation

Micro/nanodevices for assessment and treatment in stomatology and ophthalmology

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Microsystems & Nanoengineering 2021年第1期7卷 1-19页

作者： An’an Sheng long Lin Jia Zhu jian Zhuang jian Li Lingqian Chang Huanyu cheng The Institute of Single Cell Engineering Beijing Advanced Innovation Center for Biomedical Engineering School of Biological Science and Medical Engineering Beihang University100191 BeijingChina Department of Stomatology Xiang’An Hospital of Xiamen University361100 XiamenChina School of Stomatology North China University of Science and Technology063210 TangshanChina Institute of Plastic Machinery and Plastic Engineering School of Mechanical and Electrical EngineeringBeijing University of Chemical Technology100029 BeijingChina Department of Engineering Science and Mechanics Pennsylvania State UniversityUniversity ParkPA 16802USA.6 School of Biomedical EngineeringResearch and Engineering Center of Biomedical MaterialsAnhui Medical University230032 HefeiChina

Micro/nanodevices have been widely applied for the real-time monitoring of intracellular activities and the delivery of exogenous substances in the past few *** review focuses on miniaturized micro/nanodevices for assessment and treatment in stomatology and *** first summarize the recent progress in this field by examining the available materials and fabrication techniques,device design principles,mechanisms,and biosafety aspects of micro/*** a discussion of biochemical sensing technology from the cellular level to the tissue level for disease assessment,we then summarize the use of microneedles and other micro/nanodevices in the treatment of oral and ocular diseases and conditions,including oral cancer,eye wrinkles,keratitis,and *** with the identified key challenges,this review concludes with future directions as a small fraction of vast opportunities,calling for joint efforts between clinicians and engineers with diverse backgrounds to help facilitate the rapid development of this burgeoning field in stomatology and ophthalmology.

关键词： treatment directions assessment

long-term outcomes of PCI vs. CABG for ostial/midshafl lesions in unprotected left main coronary artery

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Journal of Geriatric Cardiology 2017年第4期14卷 254-260页

作者： cheng-long GUO Xian-Peng YU Bang-Guo YANG meng-meng LI Ji-Qiang HE Quan LI cheng-Xiong GU Shu-Zheng LYU jian-Zeng DONG Department of Cardiology Beijing Anzhen Hospital Capital Medical University Beijing China Department of Cardiac Surgery Beijing Anzhen Hospital Capital Medical University Beijing China

Background There are limited data on long-term （〉 5 years） outcomes of drug-eluting stent （DES） implantation compared with coro- nary artery bypass grafting （CABG） for ostial/rnidshaft left main coronary artery （LMCA） lesions. Methods Of the 259 consecutive pa- tients in Beijing Anzhen Hospital with ostial/midshaff LMCA lesions, 149 were treated with percutaneous coronary intervention （PCI） with DES and 110 were with CABG. The endpoints of the study were death, repeat revascularization, myocardial infarction （MI）, stroke, the composite of cardiac death, and major adverse cardiac and cerebrovascular events （MACCE, the composite of cardiac death, MI, stroke or repeat revascularization）.The duration of follow-up is 7.1 years （interquartile range 5.3 to 8.2 years）. Results There is no significant differ- ence between the PCI and CABG group during the median follow-up of 7.1 years （interquartile range： 5.3-8.2 years） in the occurrence of death （HR： 0.727, 95% CI： 0.335-1.578; P = 0.421）, the composite endpoint of cardiac death, MI or stroke （HR： 0.730, 95% CI： 0.375-1.421; P = 0.354）, MACCE （HR： 1.066, 95% CI： 0.648-1.753; P = 0.801）, MI （HR： 1.112, 95% CI： 0.414-2.987; P = 0.833）, stroke （HR： 1.875, 95% CI： 0.528-6.659; P = 0.331）, and repeat revascularization （HR： 1.590, 95% CI： 0.800-3.161; P = 0.186）. These results remained after multivariable adjusting. Conclusion During a follow-up up to 8.2 years, we found that DES implantation had similar endpoint outcomes compared with CABG.

关键词： Coronary artery bypass graft Drug-eluting stent Percutaneous coronary intervention

A Cation-Driven Approach toward Deep-Ultraviolet Nonlinear Optical Materials

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Research 2023年第3期2023卷 781-791页

作者： Cong Hu meng cheng Wenqi Jin jian Han Zhihua Yang Shilie Pan Research Center for Crystal Materials CAS Key Laboratory of Functional Materials and Devices for Special EnvironmentsXinjiang Technical Institute of Physics&ChemistryCAS40–1 South Beijing RoadUrumqi 830011China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

The design of new materials with special performances is still a great challenge,especially for the deep-ultraviolet nonlinear optical materials in which it is difficult to balance large bandgaps and strong second harmonic generation responses due to their inverse *** variation not only influences the whole structure frameworks but also directly participates in the formation of electronic structures,both of which could lead to the uncontrollability of the properties of the designed ***,a novel approach,aiming at purposeful and foreseeable material designs,is proposed to characterize the role of *** the verification of several series of borates,the influences of cation variation on property changes are explored ***,a feasible strategy of designing deep-ultraviolet nonlinear optical materials by substituting barium for lead has been concluded,which could obviously blue-shift the ultraviolet cutoff edge and maintain the relatively strong second harmonic generation response(more than 2 times of KH2PO4),achieving the property optimization,and especially works efficiently in *** property optimization design strategy and the cation characterization method are not only helpful in exploring nonlinear optical materials but also enlightening in material design and selection.

关键词： materials ultraviolet property

Single transition-metal atoms anchored on a novel Diracdispersiveπ-πconjugated holey graphitic carbon nitride substrate:computational screening toward efficient bifunctional OER/ORR electrocatalysts

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Rare Metals 2024年第8期43卷 3819-3832页

作者： Chun-Yao Fang Xi-Hang Zhang Qiang Zhang Di Liu Xiao-meng Cui Jing-cheng Xu cheng-long Shi meng-Yu Yang College of Science University of Shanghai for Science and TechnologyShanghai 200093China School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai 200093China

Nonprecious-metal-group single-metal-atom catalysts with bifunctional catalytic capabilities toward the oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)are highly sought after in energy-conversion and storage ***,producing renewable and sustainable energy sources remains ***,single-transition metal atoms anchored onπ-πconjugated two-dimensional(2D)graphitic carbon nitride substrates formπ-d conjugated conductive channels that enhance the overall electrocatalytic ***,firstprinciples calculations were carried out to design and demonstrate a novel macropore graphitic carbon nitride(gC_(10)N_(3))as a promising 2D electrocatalyst substrate to support single-transition metal(TM,from Sc to Au).The"donation-acceptance"charge interaction in the TM-N_(2)moiety effectively balances the adsorption strength of oxygenated intermediates in Ni@g-C_(10)N_(3)and Rh@gC_(10)N_3,making them effective bifunctional OER/ORR electrocatalysts with IrO_(2)/Pt-beyond overpotentials being as low as 0.39/0.38 V and 0.54/0.44 V,***,they possess high stability and conductivity and are less susceptible to oxidation and corrosion under working *** guarantees high activity under ambient ***,the origin of the OER/ORR activity of TM@g-C_(10)N_(3) is explained using multilevel descriptors:intrinsic(p,Bader charge,integral crystal orbital Hamilton population(ICOHP),bond length,and d-band center(εd).In particular,for optimal Ni@g-C_(10)N_(3),the clear hybridization between the Ni-d orbital and surface O-p orbital causes the paired electrons to occupy the bonding *** enables OH~*to be adsorbed on the Ni@g-C_(10)N_(3),thereby achieving the highest catalytic performance.

关键词： First-principles calculation Oxygen evolution reaction Oxygen reduction reaction Bifunctional electrocatalysts Single-metal-atom electrocatalysts