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PREcIPITATION BEhAVIOR IN A cu-Sn-Ni-Zn-P LEAD FRAME MATERIAL

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Acta Metallurgica Sinica(English Letters) 2003年第3期16卷 155-160页

作者： W.h.Tian c.k.Yan M.Nemoto Department of Materials Physics and chemistry University of Science and Technology BeijiingBeijing 100083ChinaInstitute of Metal ResearchThe Chinese Academy of SciencesShenyang 110016ChinaSasebo National College of Technology Okishin 1-1 Sasebo 857-1193 Japan

Transmission electron microscopy (TEM) observations were carried out for examining the precipitation behavior in a cu-Sn-Ni-Zn-P lead frame material. TEM observations revealed that the precipitate is hexagonal Ni5P2 and the orientation relationship between the cu matrix and Ni$Pi precipitate is (111)fcc//(0001)hcp, [101]fcc//[1120]hcp, where the suffix fcc denotes the cu matrix and hep denotes the hexagonal Ni5P2 precipitate. The Ni5P2 precipitate is ovoidal in shape at the beginning of aging at lower temperature. By prolonging the aging time or increasing the aging temperature, Ni5P2 precipitate grows and shows a rod-like shape. The Ni added cu based lead frame material has a comparative mechanical properties with that of TAMAc15 which has been developed and used in electrical industry.

关键词： lead frame materials mechanical properties atom diffusion precipitate transmission electron microscopy

EFFEcT OF DEEP cOLD TREATMENT ON TWO cASE hARDENING STEELS

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Acta Metallurgica Sinica(English Letters) 2008年第1期21卷 1-7页

作者： c.h.Surberg P.Stratton k.Lingenhle V-Research center of competence for Tribology and Technical Logistics Gmbh DornbirnAustriap The Linde Group UnterschleiβheimGermany Lingenhle Technology Gmbh FeldkirchAustria

Although cold treatments have been used to reduce the retained austenite in the cases of carburised steel for many years, there is little data on deep cold temperatures below -70℃ or treatment times longer than an hour or two. This study set out to determine the effects of such deep cold treatments at temperatures -150℃ for 24 h. The study investigated the effects of deep cold on the microstructure, hardness profile, residual stress and internal oxidation on two typical carburising steels, 16Mncr5 and 21NicrMo2. The study found that for both 16Mncr5 and 21NicrMo2 carburised to a case depth of approximately 0.8 mm, the longer and colder the deep cold treatment, the more the austenite retained in the case was converted to martensite and the harder it became. After low temperature tempering, the hardness difference was smaller, but still significant. In both steels, the case appeared more refined and homogeneous after deep cold treatment. Deep cold treatment had a negligible effect on the core properties of either steel.

关键词： carburised steel Deep cold Retained austenite

Novel AR-based interface for human-robot interaction and visualization

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Advances in Manufacturing 2014年第4期2卷 275-288页

作者： h.c.Fang S.k.Ong A.Y.c.Nee Department of Mechanical Engineering Faculty of EngineeringNational University of Singapore9 Engineering Drive 1Singapore 117576Singapore

Intuitive and efficient interfaces for human- robot interaction （hRI） have been a challenging issue in robotics as it is essential for the prevalence of robots supporting humans in key areas of activities. This paper presents a novel augmented reality （AR） based interface to facilitate human-virtual robot interaction. A number of human-virtual robot interaction methods have been for- mulated and implemented with respect to the various types of operations needed in different robotic applications. A Euclidean distance-based method is developed to assist the users in the interaction with the virtual robot and the spatial entities in an AR environment. A monitor-based visualization mode is adopted as it enables the users to perceive the virtual contents associated with different interaction methods, and the virtual content augmented in the real environment is informative and useful to the users during their interaction with the virtual robot. case researches are presented to demonstrate the successful implementation of the AR-based hRI interface in planning robot pick-and-place operations and path following operations.

关键词： human-robot interaction (hRI) human-robot interface Augmented reality (AR)

Evaluation of microstructure and mechanical properties of Mg-xce-0.5Zn alloys by nano-indentation

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Transactions of Nonferrous Metals Society of china 2010年第7期20卷 1240-1243页

作者： k.c.PARk B.h.kIM Y.h.PARk I.M.PARk Department of Material Science and Engineering Pusan National UniversitySan 30 Jangjeon-dongGeumjeong-guBusan 609-735Korea

The microstructure and mechanical properties of Mg-xce-0.5Zn （x=0.5, 1.5, 2.5, molar fraction, %） alloys were examined using a nano-indentation technique. The alloys were fabricated using a vacuum induction melting method under an argon atmosphere The microstruetures of Mg-xce-0.5Zn alloys mainly consist ofa-Mg and eutectic Mg12ce phase. The volume fraction and size of the eutectic Mgl2ce phase increase with increasing ce contents. Nano-indentation test results show that the indentation hardness and elastic modulus of the eutectic Mg12ce phase are higher than those of the a-Mg matrix. In addition, the mean indentation hardness and elastic modulus of the Mg-xce-0.5Zn alloys increase with the ce addition amount increasing.

关键词： Mg alloys Mg-ce-Zn rare earth microstructure mechanical properties nano-indentation

cryptic species composition and genetic diversity within Bemisia tabaci complex in soybean in India revealed by mtcOI DNA sequence

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Journal of Integrative Agriculture 2015年第9期14卷 1786-1795页

作者： Prasanna h c kanakala S Archana k Jyothsna P Varma R k Malathi V G Division of Vegetable Improvement Indian Institute of Vegetable Research Advanced centre for Plant Virology Division of Plant PathologyIndian Agricultural Research Institute Department of Plant Pathology Jawaharlal Nehru Krishi Vishwavidyalaya

Bemisia tabaci is a cryptic species complex, causing signiifcant loss on many agricultural y important crops worldwide. knowledge on species composition and diversity within B. tabaci complex is critical for evolving sustainable pest management strategies. here we investigate the whitelfy species complex in soybean in major soybean growing states of India. The mitochondrial cytochrome oxidase gene subunit-1 (mtcOI) based phylogenetic relationships established using Bayesian methods indicated the existence of three cryptic species namely Asia I, Asia II 1, and Asia II 7. Al the haplotypes detected in the study could be assigned to these three cryptic species fol owing the species demarcation criteria of 3.5%divergence threshold. Of these, Asia II 1 was found to be predominant with wide spread distribution across the surveyed regions from cool temperate zones to hot and humid tropical plains. On the contrary, cryptic species Asia II 7 showed localized distribu-tion. The Asia II 1 exhibited the highest haplotype diversity and Asia I showed high level of nucleotide diversity. There was a signiifcantly high genetic differentiation among these three cryptic species. The MEAM 1, a dreadful invasive species was not detected in the specimens tested in the current study. The diversity and distribution of three cryptic species is discussed in the light of current knowledge on distribution of whitelfy species in India and yel ow mosaic disease observed during sampling survey.

关键词： whitefly mitochondrial cytochrome oxidase gene subunit-1 AsiaⅠ AsiaⅡ 1 AsiaⅡ 7 begomovirus and yellow mosaic disease

The Formation of Nano-Size SiO_2 Thin Film on an Aluminum Plate with hexamethyldisilazane (hMDSA) and hexamethyldisiloxane (hMDSO)

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Journal of Thermal Science 2003年第1期12卷 89-96页

作者： h.k.Ma E.Zhao k.M.chung c.L.Yeh Dept of Mechanical Engineering National Taiwan UniversityDept of Mechanical Engineering National Taiwan UniversityDept of Mechanical Engineering National Taiwan UniversityDept of Mechanical Engineering Da-Yeh University 112 Taipei Taiwan 10764 China Taipei Taiwan 10764 ChinaTaipei Taiwan 10764 ChinaShan-Jeau Rd Dah-Tsuen Chang-Hwa Taiwan 51505 China

This study is using hMDSA (c6h19NSi2) or hMDSO (c6h18OSi2) vapor into c3h8/air premixed flames to form SiO2 thin film on the surface of an aluminum plate. With the addition of hMDSO or hMDSA to premixed flames, an orange secondary flame or a flame brush appeared and was contributed to the formation of Sio2 particles. Based upon the EDS, XPS and FTIR analysis, it is believed that the synthesized products consist of mainly SiO2 and a small amount of SiO. The pure SiO2 crystal structure, was proved by XRD analysis, which may form from the SiO2 amorphous structure after high temperature (1300c) thermal treatment. The nano-size SiO2 particles, which ranged from 2.5-25 nm, are proved by analysis of the BET and TEM. A 2-D cFD-Rc code with 12 reduced chemical reaction mechanism, based upon the SIMPLER procedure, was successfully employed to predict the flame temperature and both of the SiO2 and SiO concentration profiles. compared with the experimental results, the calculated temperature profiles in the post-flame region are in good agreement with the measured data and observation phenomena.

关键词： nano size thin film SiO2.

Influence of surface treatments on fatigue life of a two-stroke free piston linear engine component using random loading

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第11期7卷 1819-1830页

作者： RAhMAN M.M. ARIFFIN A.k. JAMALUDIN N. hARON c.h.c. Department of Mechanical and Materials Engineering Faculty of Engineering Universiti Kebangsaan Malaysia 43600 UKM Bangi Selangor DE Malaysia

This paper describes the finite element (FE) analysis technique to predict fatigue life using the narrow band frequency response approach. The life prediction results are useful for improving the component design methodology at the very early development stage. The approach is found to be suitable for a periodic loading but requires very large time records to accurately describe random loading processes. This paper is aimed at investigating the effects of surface treatments on the fatigue life of the free piston linear engine’s components. Finite element modelling and frequency response analysis were conducted using computer aided design and finite element analysis commercial codes, respectively. In addition, the fatigue life prediction was carried out using finite element based fatigue analysis commercial code. Narrow band approach was specially applied to predict the fatigue life of the free piston linear engine cylinder block. Significant variation was observed between the surface treatments and untreated cylinder block of free piston engine. The obtained results indicated that nitrided treatment yielded the longest life. This approach can determine premature products failure phenomena, and therefore can reduce time to market, improve product reliability and customer confidence.

关键词： Vibration fatigue Finite element (FE) Power spectral density function Frequency response Surface treatment

VARIATION OF SUBSTRUcTURES OF PEARLITIc hEAT RESISTANT STEEL AFTER hIGh TEMPERATURE AGING

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 477-481页

作者： R.c.Yang k.chen h.X.Feng h.Wang State key Lab. of Advanced Nonferrous Materials Lanzhou University of Technology Lanzhou 730050ChinaState Key Lab. of Advanced Nonferrous Materials Lanzhou University of Technology Lanzhou 730050ChinaState Key Lab. of Advanced Nonferrous Materials Lanzhou University of Technology Lanzhou 730050ChinaState Key Lab. of Advanced Nonferrous Materials Lanzhou University of Technology Lanzhou 730050China

The observations of dislocations, substructures and other microstructural details were conducted mainly by means of transmission electron microscope (TEM) and scanning electron microscope (SEM) for 12crlMoV pearlitic heat-resistant steel. It is shown that during the high temperature long-term aging, the disordered and jumbled phase-transformed dislocations caused by normalized cooling are recovered and rearranged into cell substructures, and then the dislocation density is reduced gradually. Finally a low density linear dislocation configuration and a stabler dislocation network are formed and ferritic grains grow considerably.

关键词： pearlitic heat-resistant steel aging recovery dislocation substructure dislocation cell

A case Study of heat Transfer from hot Runner Mould to the Fix Platen of the Injection-moulding Machine

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厦门大学学报（自然科学版） 2002年第S1期41卷 97-98页

作者： c h Tan k S Lee School of Mechanical & Manufacturing Engineering Department of Mechanical Engineering National University of Singapore Singapore Polytec hnic SingaporeSingapore

In an injection moulding process, the parallelism b et ween the tie bars of the injection moulding machine is very important as it will affect the mould closing and clamping system. In recent years, more and more ho t runner systems are being applied in the moulding industry to save material and decrease the losses of injection pressure. heat transfer from hot runner system from the fixed half which is secured in the fix machine platen could transmit s o much heat that it may cause high temperature differential between the machine fix platen and moving platen. This will cause the tie bar to become unparallel. Part quality will be compromised and the wear of the tie bar will be excessive. Overhaul of the tie bar may be necessary after a short period of time which is c ostly. This raises the need to analyze the heat transfer from the hot runner sys tem to the machine fix platen and the methods of isolating or minimizing the hea t transfer. In this case study, a photo lens article mould was used. The mould w as built with a direct hot runner nozzle system. heat conduction from hot runner and machine screw to machine fix platen were studied based on either using high temperature heat insulating plate put in placed between the mould and the mould ing machine fix platen or drill cooling channels in the front mould clamping pla te. The high temperature insulator is very costly as it is made out of glass re inforced polymer composite material. Experimental results were obtained and anal yzed to find the best method to minimize the unwanted heat transfer using the ch eapest and most effective method.

关键词： injection moulding cooling hot runner system i njection moulding machine platen tie bar