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PlASTIC DEFORMATION BEHAVIOR OF ElECTROFORMED COPPER lINER OF SHAPED CHARGE AT DIFFERENT STRAIN RATES

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Acta Metallurgica Sinica(English letters) 2003年第1期16卷 72-77页

作者： H.Y.Gao W.H.Tian a.l.fan Q.Sun Dept. of Mat. Phys. and Chem. Univ. of Sci. and Technol. Beijing Beijing 100083 China 210 Inst. Beijing 100081 China

The paper deals with different plastic deformation behavior of electroformed copper liner of shaped charge, deformed at high strain rate (about 1×107s-1) and normal strain rate (4×10-4s-1). The crystallographic orientation distribution of grains in recovered slugs which had undergone high-strain-rate plastic deformation during explosive detonation was investigated by electron backscattering Kikuchi pattern technique. Cellular structures formed by tangled dislocations and sub-grain boundaries consisting of dislocation arrays were detected in the recovered slugs. Some twins and slip dislocations were observed in specimen deformed at normal strain rate. It was found that dynamic recovery and recrystallization take place during high-strain-rate deformation due to the temperature rising, whereas the conventional slip mechanism operates during deformation at normal strain rate.

关键词： electroformation electron backscattering Kikuchi pattern cellular dislocation structure ultra-high-strain-rate deformation dynamic recovery and recrystallization

TEM AND EBSP INVESTIGATION ON THE MICROSTRUCTURES OF ElECTROFORMED COPPER lINER AFTER PlASTIC DEFORMATION AT DIFFERENT STRAIN RATES

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TEM AND EBSP INVESTIGATION ON THE MICROSTRUCTURES OF ELECTRO...

Multi-objective quality control method for cold-rolled products oriented to customized requirements

The China-Japan Joint Seminar on Atomic level Characterization-2002

作者： W.H.Tian~1) a.l.fan~1) H.Y.Gao~1) Q.Sun~2) 1)Department of Materials Physics and Chemistry University of Science and Technology Beijing Beijing 100083 China 2)Box No.2413 210 Institute Beijing 100081 China

＜正＞1. Introduction Electroforming technique has been used for fabricating copper liner of shaped charge, which is used as armor penetrator in both commercial and military application,because it makes the materials possible to have ultra-fine grains[1,2].Experimental work has shown that decrease in grain size of the liners of shaped charges can dramatically improve the penetration depth during explosive detonation ***,it is very important to make the plastic deformation mechanism clear in order to understand the relation between microstructure of copper liner and penetration depth during explosive detonation deformation.

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International Journal of Minerals,Metallurgy and Materials 2021年第8期28卷 1332-1342页

作者： Yi-fan Yan Zhi-min lü Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China

To deal with the increasing demand for low-volume customization of the mechanical properties of cold-rolled products, a two-way control method based on mechanical property prediction and process parameter optimization(PPO) has become an effective solution. Aiming at the multi-objective quality control problem of a company's cold-rolled products, based on industrial production data, we proposed a process parameter design and optimization method that combined multi-objective quality prediction and PPO. This method used the multi-output support vector regression(MSVR) method to simultaneously predict multiple quality indices. The MSVR prediction model was used as the effect verification model of the PPO results. It performed multi-process parameter collaborative design and realized the optimization of production process parameters for customized multi-objective quality requirements. The experimental results showed that, compared with the traditional single-objective quality prediction model based on support vector regression(SVR), the multi-objective prediction model could better take into account the coupling effect between process parameters and quality index, the MSVR model prediction accuracy was higher than that of the SVR, and the optimized process parameters were more capable and reflected the influence of metallurgical mechanism on the quality index,which were more in line with actual production process requirements.

关键词： customized production quality control multi-objective prediction multi-output support vector regression process parameter optimization

lake sediment resuspension and caused phosphate release——a simulation study

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Journal of Environmental Sciences 2001年第4期13卷 406-410页

作者： fan, CX Zhang, l Qu, TC Chinese Acad Sci Nanjing Inst Geog & Limnol Nanjing 210008 Peoples R China

Intact sediment cores and wet/dried surficial sediments sampled from the two sublakes in Taihu lake, Meiliang Bay and Wuli lake, were incubated in the laboratory to determine the effects of resuspension on internal phosphorus loading by simulating different resuspension events. Soluble reactive phosphorus (SRP) release from undisturbed core sediment sampled in the Meiliang Bay and Wuli lake in July 1998 was 1.53 mg/m(2) and 2.24 mg/m(2) within 4 days, respectively. However during one hour experimental simulation of resuspension, SRP increased by 0.041 mg/l and 0.077 mg/l in die above cores, which indicate that a typical resuspension event in the take would be accompanied by the release of 10.77 mgSRP/m(2) and 23.1 mgSRP/m(2), respectively. The internal phosphorus loading induced by resuspensian is estimated to be 8 - 10 times greater than the release from undisturbed sediment. SRP release from the dried sediments during simulation of resuspension was mainly dependent on the disturbing intensity. Only when the wind strength gets to certain level, the influence of wind speed on phosphorus release appears significant, indicating that an exchangeable P pool, capable of altering equilibrium conditions in the take areas, is built up under strongly wind-exposed resuspension events.

关键词： sediment resuspension simulation phosphate release Taihu lake

Effect of Pressure on the Nucleation of Diamond with Addition of Oxygen in the Microwave Plasma Chemical Vapor Deposition System

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Chinese Physics letters 1996年第6期13卷 473-476页

作者： WANG Jian-jun lÜfan-xiu Department of Materials Science and Engineering Beijing University of Science and TechnologyBeijing 100083

Effect of oxygen addition on diamond film deposition at higher pressure was *** was found that addition of oxygen suppressed diamond nucleation,and the effect of suppression increased with increasing pressure,and at certain pressure level diamond deposition was completely *** effect due to oxygen addition dominated at the very early stage(nucleation stage),therefore it is still possible to take the advantage of oxygen addition on quality improvement of diamond films by introducing oxygen after the nucleation stage.

关键词： Diamond Oxygen effect

Effect of crystallographic orientation on crack growth behaviour of HSlA steel

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International Journal of Minerals,Metallurgy and Materials 2022年第8期29卷 1532-1542页

作者： Endian fan Yong li Yang You Xuewei lü College of Materials Science and Engineering Chongqing UniversityChongqing 400045China Corrosion and Protection Center University of Science and Technology BeijingBeijing 100083China State Key laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China

In this work,the crack growth behaviours of high strength low alloy(HSlA)steel E690 with three crystallographic orientations(the rolling direction,normal direction,and transverse direction)were investigated and compared from the view of the mechano-electrochemical ef-fect at the crack *** results show that the crack growth of the HSlA steel is controlled by the corrosion fracture at the crack *** vari-ation of crystallographic orientation in E690 steel plate has no influence on the crack tip electrochemical reaction and crack growth mechanism,but changes the crack growth *** the stress loading direction is parallel to the rolling direction and the fracture layer is parallel to the transverse-normal plane,the crack growth rate is the slowest with a value of 0.0185 mm·h^(-1).When the load direction and the fracture layer are parallel to the normal direction and the rolling-transverse plane,respectively,the crack growth rate is the highest with a value of 0.0309 mm·h^(-1).This phenomenon is ascribed to the different microstructural and mechanical properties in the rolling direction,normal direction,and transverse direction of E690 steel plate.

关键词： high strength low alloy steel crystallographic orientation microstructural characteristic crack growth mechanism hydrogen induced cracking

Importance of storage time in mesophilic anaerobic digestion of food waste

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Journal of Environmental Sciences 2016年第7期28卷 76-83页

作者： fan lü Xian Xu liming Shao Pinjing He State Key laboratory of Pollution Control and Resource Reuses Tongji University Institute of Waste Treatment and Reclamation Tongji University Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area Ministry of Housing and Urban–Rural Development of PR China

Storage was used as a pretreatment to enhance the methanization performance of mesophilic anaerobic digestion of food waste. Food wastes were separately stored for 0, 1,2, 3, 4, 5, 7, and 12 days, and then fed into a methanogenic reactor for a biochemical methane potential（BMP） test lasting up to 60 days. Relative to the methane production of food waste stored for 0–1 day（285–308 m l/g-added volatile solids（VSadded））, that after2–4 days and after 5–12 days of storage increased to 418–530 and 618–696 m l/g-VSadded,respectively. The efficiency of hydrolysis and acidification of pre-stored food waste in the methanization reactors increased with storage time. The characteristics of stored waste suggest that methane production was not correlated with the total hydrolysis efficiency of organics in pre-stored food waste but was positively correlated with the storage time and acidification level of the waste. From the results, we recommend 5–7 days of storage of food waste in anaerobic digestion treatment plants.

关键词： Food waste Bio-pretreatment Storage Fermentation Biochemical methane potential Hydrolysates

Stratospheric entry point for upper-tropospheric air within the Asian summer monsoon anticyclone

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Science China Earth Sciences 2017年第9期60卷 1685-1693页

作者： fan QiuJun BIAN JianChun laura l.PAN Key laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China College of Earth Sciences University of Chinese Academy of Sciences Beijing 100049 China National Center for Atmospheric Research Boulder CO 80301 USA

The Asian summer monsoon(ASM) anticyclone isolates upper-tropospheric air within the interior of the anticyclone from the outside. Forward trajectory simulations in previous studies have shown that much of the air within the ASM anticyclone can be trapped for up to two or three weeks, not only laterally but also vertically. Here, we investigate the locations of exit points for upper-tropospheric air trapped within the ASM anticyclone, especially the preferred tropopause-crossing locations, using a 3-dimensional trajectory model. Forward trajectory calculations show two-thirds of the air crosses the tropopause at the southern part of the anticyclone via upward diabatic transport. Furthermore, some air crosses at northern and eastern parts via isentropic shedding, but air crosses rarely through the center of the anticyclone. However, calculations also show that many stratospheric parcels within the anticyclone are traceable from the upper-tropospheric anticyclone. This implies they cannot break through the tropopause directly overhead but instead enter the stratosphere via other entry points.

关键词： Asian summer monsoon anticyclone Tropopause Stratosphere-troposphere exchange Trajectory simulation

Cost effective approach to identify multiple influential spreaders based on the cycle structure in networks

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Science China(Information Sciences) 2023年第9期66卷 184-193页

作者： Wenfeng SHI Shuqi XU Tianlong fan linyuan lü Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of China Institute of Dataspace Hefei Comprehensive National Science Center Department of Physics University of Fribourg Alibaba Research Center for Complexity Sciences Hangzhou Normal University

Identifying influential spreaders has theoretical and practical significance in complex *** centrality methods can efficiently find a single spreader, but it could lead to influence redundancy and high initializing costs when used to identify a set of multiple spreaders. A cycle structure is one of the most crucial reasons for the complexity of a network and the cornerstone of the feedback effect. From this novel perspective, we propose a new method based on basic cycles in networks to identify multiple influential spreaders with superior spreading performance and low initializing costs. Experiments on six empirical networks show that the spreaders selected by the proposed method are more scattered in the network and yield the best spreading performance compared with those on seven well-known methods. Importantly, the proposed method is the most cost effective under the same spreading performance. The cycle-based method has the advantage of generating multiple solutions. Our work provides new insights into identifying multiple spreaders and hence can benefit wide applications in practical scenarios.

关键词： multiple spreaders basic cycle complex network cycle structure spreading dynamics