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Assessment of Deformation of shear Localized chip in High speed Machining

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厦门大学学报（自然科学版） 2002年第S1期41卷 11-12页

作者： T c LEE w s LAU s K cHAN Industrial system Engineering Department Hong Kong Polytechnic UniversityHong Kong Institute of Vocational EducationGolden Tech Machinery Ltd. Hong Kong China Hong Kong China Hong Kong China

As the cutting speed goes higher, the mechanism of chip deformation will be changed significantly, i.e., continuous chip in low cutting speed will shift to serrated chip with shear localization. For the shear localized chip, the parameters used to assess the chip deformation for continuous chip, such as shorten coefficient ξ, shear angle φ and shear strain ε, can not describe the chip deformation correctly or comprehensively. This paper deals.w.th the assessment of chip deformation of shear localization. There are two deformation regions in shear localized chip, one is the chip segment body with relative smaller plastic deformation, another one is the boundary between segments.w.th shear localization, so called shear band. considering the two distinct deformation regions, two parameters are used to define their deformation respectively. According to the analysis of chip formation process, the equations have been deduced to calculate the shear strains of shear band ε, shear strain of chip segment ε 1 and shear rate so that the shear localized chip deformation can be assessed correctly and comprehensively. By use of this assessment, the chip deformation in machining selenium treated stainless steel (sTss) and common stainless steel at various cutting conditions is investigated. The experiment results obtained by the machining of stainless steel prove that: (1) the shear strain and strain rate increase with the increasing of cutting speed; (2) the shear strain in shear band can be over 10 when cutting speed exceeding 200 m/min for both types of stainless steel, and it is much higher than the strain of chip segment. The difference will be enlarged as the cutting speed increasing; (3) As the comparison, the shear strain for the sTss is a little lower than that for JIs304; (4) The stain rate is extremely high (= 2.5×10 5 1/s ). In range of cutting speed less than 180 m/min, the strain rate for sTss is lower than that for JIs304. However, when the cutting speed is higher t

关键词： chip deformation shear localization high speed machining

computational fluid dynamics simulation of the wind flow over an airport terminal building

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Journal of Zhejiang University-science A(Applied Physics & Engineering) 2010年第6期11卷 389-401页

作者： chun-ho LIU Dennis Y.c.LEUNG Alex c.s.MAN P.w.cHAN Department of Mechanical Engineering The University of Hong Kong Hong Kong Observatory

Turbulence in the wake generated by wind flow over buildings or obstacles may produce complex flow patterns in downstream *** include the recirculating flow and wind deficit areas behind an airport terminal building and their potential impacts on the aircraft landing on nearby runways.A computational fluid dynamics(cFD) simulation of the wind flow over an airport terminal building was performed in this study of the effect of the building wake on landing *** normal meteorological conditions,the studied airport terminal building causes limited effects on landing aircraft because most of the aircraft have already landed before entering the turbulent wake *** simulating the approach of a tropical cyclone,additional cFD sensitivity tests.w.re performed to study the impacts of building wake under extreme meteorological *** was found that,in a narrow range of prevalent wind directions.w.th wind speeds larger than a certain threshold value,a substantial drop in wind speed(>3.6 m/s) along the glide path of aircraft was observed in the building *** cFD results also showed that under the most critical situation,a drop in wind speed as large as 6.4 m/s occurred right at the touchdown point of landing aircraft on the runway,an effect which may have a significant impact on aircraft *** study indicated that a comprehensive analysis of the potential impacts of building wake on aircraft operations should be carried out for airport terminals and associated buildings in airfields to ensure safe aviation operation under all meteorological conditions and to facilitate implementation of precautionary measures.

关键词： Aviation safety Building aerodynamics computational fluid dynamics (cFD) k-e turbulence model Tropicalcyclone

Optical spectroscopy study of charge density wave order in sr3Rh4sn13 and(sr0.5ca0.5)3Rh4sn13

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science china(Physics,Mechanics & Astronomy) 2017年第4期60卷 51-56页

作者： w.J.Ban H.E wang c.w.Tseng c.N.Kuo c.s.Lue N.L.wang Institute of Physics Chinese Academy of SciencesBeijing 100190China Department of Physics Cheng Kung UniversityTainan 70101China International center for Quantum Materials School of PhysicsPeking UniversityBeijing 100871China collaborative Innovation center of Quantum Matter Beijing 100871China

we perform optical spectroscopy measurement on single-crystal samples of sr3Rh4sn13 and （sr0.5ca0.5）3Rh4sn13. Formation of cDw energy gap was clearly observed for both single-crystal samples.w.en they undergo the phase transitions. The existence of residual Drude components in σ1（ω） below Tcow indicates that the Fermi surface is only partially gapped in the cDw state. The obtained value of 2A/kBTcow is roughly 13 for both sr3Rh4sn13 and （sr0.5ca0.5）3Rh4sn13 compounds, which is considerably larger than the mean-field value based on the weak-coupling Bcs theory. The measurements provide optical evidence for the strong coupling characteristics of the cDw phase transition.

关键词： charge density wave optical spectroscopy intermetallic compounds

characterization of Fe_3O_4/P(st-MPEO) Amphiphilic Magnetic Polymer Microspheres

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chemical Research in chinese Universities 2002年第4期18卷 458-461页

作者： cHAN ALBERT s. c. YIP c. w. Open Laboratory of chirotechnology and Department of Applied Biology and chemical Technology Open Laboratory of Chirotechnology and Department of Applied Biology and Chemical Technology Hong Kong Polytechnic University Hong Kong P. R. ChinaHong Kong Polytechnic University Hong Kong P. R. China

Amphiphilic magnetic microspheres consisting of styrene and poly(ethylene oxide) macromonomer(MPEO) were prepared by dispersion copolymerization in the presence of Fe_3O_4 magnetic fluid in an ethanol/water medium. The sizes of the magnetic microspheres and their distribution were characterized by means of scanning electron microscopy(sEM). The surface morphology and the average surface roughness of the microspheres.w.re investigated by virtue of atomic force microscopy(AFM). It was found that the microspheres exhibit microscopic phase-separate and the mean square surface roughness of the microspheres increases.w.th increasing MPEO used in the copolymerization. The amphiphilic magnetic microspheres containing 0 4-3 5 mg/g hydroxyl groups could be prepared from MPEO with different concentrations and styrene.

关键词： Amphiphilic magnetic polymer Microsphere copolymerization

Experimental Observation of Bright and Dark solitons Mode-Locked with Zirconia-Based Erbium-Doped Fiber Laser

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chinese Physics Letters 2018年第2期35卷 25-28页

作者： A.M.Markom s.J.Tan H.Haris M.c.Paul A.Dhar s.Das s.w.Harun Faculty of Electrical Engineering Universiti Teknologi MARAMasai 81750Malaysia school of Engineering KDU University CollegeUtropolis GlenmarieShah Alam 40150Malaysia Department of Electrical Engineering University of MalayaKuala Lumpur 50603Malaysia Fiber Optics and Photonics Division CSIR-Central Glass and Ceramic Research InstituteKolkata 700032India

we demonstrate the generation of dark and bright solitons.w.th our homemade zirconia-based erbium-doped fiber and graphene oxide（GO） saturable absorber in anomalous dispersion *** GO is fabricated using an abridged Hummer＇s method,which is combined with polyethylene oxide to produce a composite *** film is sandwiched between two optical ferrules and embedded in the laser cavity to enhance its birefringence and *** self-starting bright soliton is easily generated at pump power of 78 mw with the whole length cavity of 14.7 *** laser produces the bright pulse train with repetition rate,pulse width,pulse energy and central wavelength being 13.9 MHz,0.6 ps,2.74 p J and 1577.46 nm,***,by adding the 10 m of single mode fiber into the laser cavity,dark soliton pulse is *** the formation of dark pulse train,the measured repetition rate,pulse width,pulse energy and central wavelength are 8.3 MHz,20 ns and 4.98 p J and1596.82 nm,*** pulses operate in the anomalous region.

关键词： Zr EDF Experimental Observation of Bright and Dark solitons Mode-Locked with Zirconia-Based Erbium-Doped Fiber Laser

Maneuvering Modeling and simulation of AUV Dynamic systems.w.th Euler-Rodriguez Quaternion Method

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china Ocean Engineering 2013年第3期27卷 403-416页

作者： c.w.chen J.s.Kouh J.F.Tsai Department of science Engineering and Ocean Engineering National Taiwan University

The purpose of this study is to develop maneuvering models and systems of a simulator to improve the motion performance of autonomous underwater vehicles （AUVs） at the preliminary design stages in advance. The AUVs simulation systems based on the standard submarine equations of motion in six-degree-of-freedom （6-DOF） integrated with the Euler-Rodriguez quaternion method for representing singularity-free AUV attitude and time-saving calculation, and with a nonlinear control model for maneuvering and depth control simulations, time-marching in the fourth-order Runge-Kutta scheme. For validation of the simulation codes, results of the IsiMI AUV open-loop tests including turning test and zigzag test as.w.ll as an AUV simulator on the basis of Euler-angle method were used to compare with the quaternion-based AUV simulator. The computational results from the proposed simulator agree well with those from both the IsiMI AUV experiments and the Euler-angle based simulations. Additionally, a new maneuvering procedure, namely ＂put-out＂ was implemented to test directional stability for a large-scale AUV in the proposed AUV simulator that can be considered for vehicles in space as.w.ll as in constrained planes.

关键词： autonomous underwater vehicle (.4 UV) Euler-Rodriguez quaternion hydrodynamics maneuvering systemdynamics

The myth of “minima” and “maxima”,the species of Physalis in the Indian subcontinent

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植物分类学报 2007年第2期45卷 239-245页

作者： Vatsavaya s RAJU c s REDDY K G RAJARAO Department of Botany Kakatiya UniversityWarangal 506009 India Forestry & Ecology Division National Remote Sensing AgencyHyderabad 500008 India Department of Botany Andhra UniversityWaltair 530003 India

The status of the names, Physalis minima L. and P. maxima Mill. (solanaceae), and their alleged presence on the Indian subcontinent are discussed. The issues of nativity and identity of Linnaean Physalis minima are long-debated while the use of the name P. maxima Mill. and its report from India are recent. The available evidence indicates that the name "P. minima L." is misapplied to two different elements, viz., P. angulata L. and P. lagascae Roem. & schult. The name Physalis minima L. may be rejected as nomen confusum, for which the paper provides the primary information. As on today, it is submerged under the synonymy of P. angulata L. The correct name for the widely known P. minima is P. lagascae. The name "P. maxima Mill." applied to the escape and naturalized weed in the Indian subcontinent and els.w.ere is to be substituted by P. pruinosa L., a name misapplied to P. grisea (waterf.) M. Martínez.

关键词：酸浆属植物酸浆值植物分类植物命名

Observation of an EPIR Effect in Nd_(1-x)sr_xMnO_3 ceramics.w.th secondary Phases

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Journal of Materials science & Technology 2013年第8期29卷 737-741页

作者： s.s.chen X.J.Luo D.w.shi H.Li c.P.Yang school of Mathematics and Physics Hubei Polytechnic University Faculty of Physics and Electronic Technology Hubei University

Nd1-xsrxMnO3 （x ： 0.3, 0.5） ceramics containing a secondary phase are synthesized by high-energy ball milling and post heat-treatment method. The 4-wire and 2-wire measuring modes are used to investigate the transport character of the grain/phase boundary （inner interface） and electrode-bulk interface （outer interface）, respectively, and the results indicate that there is a similar nonlinear I-V behaviour for both of the inner and outer interfaces, however, the electric pulse induced resistance change （EPIR） effect can only be observed at the outer interface.

关键词： Electric pulse induced resistance change (EPIR) space charge layer Nonlinearity Manganite High-energy ball milling

controversies in fecal incontinence

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world Journal of Gastroenterology 2025年第3期31卷 113-119页

作者： Andreia Albuquerque satish s c Rao school of Medicine and Biomedical sciences Fernando Pessoa UniversityGondomar 4420-096PortoPortugal Precancerous Lesions and Early cancer Management Research Group RIsE@cI-IPO(Health Research Network) Portuguese Oncology Institute of PortoPorto 4200-072Portugal Division of Gastroenterology and Hepatology Department of Internal MedicineAugusta UniversityAugustaGA 30912United States

Fecal incontinence is a common condition that can significantly impact patients’quality of *** anal sphincter injury and anorectal surgeries are common *** ultrasound and anorectal manometry are important diagnostic tools for evaluating *** are various treatment options,including diet,lifestyle modifications,drugs,biofeedback therapy,tibial and sacral nerve neuromodulation therapy,and *** this editorial,we will discuss current controversies and novel approaches to fecal *** for asymptomatic anal sphincter defects after obstetric anal sphincter injury and in patients.w.th inflammatory bowel disease is not generally recommended,but may be helpful in selected *** Garg incontinence score is a new score that includes the assessment of solid,liquid,flatus,mucous,stress and urge fecal *** tests such as translumbosacral anorectal magnetic stimulation and novel therapies such as translumbosacral neuromodulation therapy are promising diagnostic and treatment options,for both fecal incontinence and *** biofeedback therapy can overcome some limitations of the office-based *** muscle-derived cell implantation of the external anal sphincter has been further studied as a possible treatment *** neuromodulation may be useful in scleroderma,congenital fecal incontinence and inflammatory bowel disease but merits further study.

关键词： Fecal incontinence Endoanal ultrasound Anal sphincter defects Biofeedback Neuropathy sacral neuromodulation