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From the Solar Wind to the Magnetospheric Substorm

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空间科学学报 2005年第5期25卷 397-405页

作者： e.A.Ponomarev P.A.Sedykh O.V.Mager Institute of Solar-Terrestrial Physics Siberia Branch Russian Academy of Sciences Irkutsk 664033 RussiaInstitute of Solar-Terrestrial PhysicsSiberia Branch Russian Academy of Sciences Irkutsk 664033 RussiaInstitute of Solar-Terrestrial PhysicsSiberia Branch Russian Academy of Sciences Irkutsk 664033 Russia

This paper gives a brief outline of the progression from the first substorm model developed in Ref.[4] and [8] based on Kennel's ideas[3], to the present views about the mechanism by which solar wind kinetic energy is converted to electromagnetic energy at the Bow Shock and by which this energy is transferred to the magnetosphere in the form of current; about the transformation of the energy of this current to gas kinetic energy of convecting plasma tubes, and, finally, the back transformation of gas kinetic energy to electromagnetic energy in secondary magnetospheric MHD generators. The questions of the formation of the magnetospheric convection system, the nature of substorm break-up, and of the matching of currents in the magnetosphere-ionosphere system are discussed.

关键词：太阳风磁场亚暴地球磁层 MHD

Diffractive Multi-beam Ultra-fast Laser Micro-processing Using a Spatial Light Modulator(Invited Paper)

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中国激光 2009年第12期36卷 3093-3115页

作者： Walter Perrie S. P. edwardson e. Fearon G. Dearden K. G. Watkins Laser Group Department of EngineeringUniversity of LiverpoolBrownlow Street

Multi-beam ultra-fast laser parallel microprocessing using spatial light modulation is demonstrated in this *** multi-beam patterns are generated with a spatial light modulator(SLM),which is driven by computer generated holograms(CGHs).The CGHs calculated by appropriate algorithms are displayed on the SLM to split an input laser beam to a number of beamlets and digitally manipulate their positions and *** undesired damage by the energetic zero order beam can be avoided by either installing a 4f optical system to block the zero order at the Fourier plane or adding a Fresnel zone lens on the CGH to defocus the zero order at the processing *** surface ablation of materials using multi-beam patterns synchronised with a scanning galvanometer system shows flexible and high throughput parallel *** tightly focusing the diffractive beams with an objective into transparent materials,high speed dynamic femto-second laser two-dimensional(2D) and three-dimensional(3D) internal structuring is also *** results demonstrate the high precision micro-processing with higher efficiency,showing the potential for ultra-fast laser parallel processing in real industrial applications.

关键词：多波束超快速激光数字处理光学系统傅里叶平面

effect of Ringer's Solution on Wear and Friction of Stainless Steel 316L after Plasma electrolytic Nitrocarburising at Low Voltages

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Journal of Materials Science & Technology 2011年第10期27卷 906-912页

作者： N.Afsar Kazerooni M.e.Bahrololoom M.H.Shariat F.Mahzoon T.Jozaghi Department of Materials Science and engineering Shiraz University

A plasma electrolytic nitrocarburising （PeN/C） process was performed on stainless steel 316L to improve the surface properties for using as medical implants. A bath was optimised to reduce the required voltage to 150 volts. Aqueous urea-based solutions with 10% NH4Cl were prepared with slightly different amounts of Na2CO3 to optimise the electrolyte composition. The surface and the cross-section morphologies were studied by scanning electron microscopy. The microstructure and the chemical composition of samples were investigated by X-ray diffraction （XRD） and energy dispersive X-ray （eDX） techniques. The microstructure of the outer layer of the coatings was found to be a complex oxide containing Cr and Fe. The wear properties of the samples were examined by using a pin on disk wear test with Ringer＇s solution and were compared with their wear properties in the ambient atmosphere. The Ringe（s solution acted as a lubricant, reducing friction coefficient. Hardness and roughness were also studied. The bath with the composition of 10% NH4CI and 3% Na2CO3 exhibited the best tribological properties. The results showed that the tribological properties of treated samples were improved and the wear mechanism was abrasion of the pin.

关键词： Plasma electrolytic nitrocarburising Ringer's solution Tribological properties

A diagnosis with a twist:Ultrasonographic sensitivity and predictors of pediatric ovarian torsion within a large pediatric hospital

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World Journal of emergency Medicine 2022年第3期13卷 229-231页

作者： Mark K.Hewitt Jesse e.Marshall-Sheppard April J.Kam Department of Medicine Division of Emergency MedicineMcMaster UniversityHamilton L8S 4L8Canada Department of Family Medicine University of TorontoToronto M5S1A1Canada Department of Pediatrics Division of Pediatric Emergency MedicineMcMaster UniversityHamilton 8S 4L8Canada

The diagnosis of ovarian torsion(OT)in girls is challenging compared to that of testicular torsion in boys for many reasons,but it behooves the medical community to continue to strive to better identify this uncommon but clinically important pathology^([1]) OT occurs when the ovary and associated structures rotate around its vascular pedicle,leading to eventually irreversible necrosis.^([2,3])Studies attempting to identify clinical features for early diagnosis have not reached a consensus on the best clinical predictors of this condition,making radiographic imaging of the ovaries even more crucial.^([4,5])

关键词： diagnosis pediatric torsion

Performance of large-diameter pneumatic down-the-hole (DTH) hammers: A focus on influences of the hammer structure

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Petroleum Science 2023年第4期20卷 2399-2412页

作者： Pin-Lu Cao Hong-Yu Cao Jin-e Cao Cheng-Da Wen Bao-Yi Chen Shan-Shan Yao College of Construction engineering Jilin UniversityNo.938 Ximinzhu StrChangchunJilin130061China

Pneumatic down-the-hole (DTH) hammer has been extensively used in air drillings through hard and ultra-hard geological formations. Numerical modeling can offer close observation on the working behaviors by visualizing internal pressure status as well as provide reliable performance predictions for large-diameter DTH hammers to which conventional empirical and experimental approaches cannot be applied. In this study, CFD simulations coupled with dynamic meshing are utilized to simulate the air flow and piston movement inside the large-diameter DTH hammers. The numerical modeling scheme is verified against a theoretical model published in literature. effects of structural parameters on hammer performance, including piston mass, piston upper-end diameter, piston groove diameter, and lengths of intake and exhaust stroke in both front and rear chambers, are analyzed in detail by virtue of sets of numerical simulations. The simulations suggest that changing the intake stroke of front chamber has a negligible influence on hammer performance while increasing the piston groove would lower all the four indicators of hammer performance, including impact energy, impact frequency, maximum stroke, and air consumption rate. Changing the other structural parameters demonstrates mixed effects on the performance indicators. Based on the numerical simulations, a large GQ-400 DTH hammer has been designed for reduced air consumption rate and tested in a field drilling practice. The air drilling test with the designed hammer provided a penetration rate 1.7 times faster than that of conventional mud drilling.

关键词： Pneumatic down-the-hole(DTH)hammer Computational fluid dynamics Dynamic mesh Gas turbulent flow Piston impact performance

Modeling of nonlinear envelope solitons in strongly coupled dusty plasmas:Instability and collision

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Chinese Physics B 2015年第3期24卷 237-247页

作者： S.K.el-Labany e.F.el-Shamy W.F.el-Taibany N.A.Zedan Department of Physics Faculty of ScienceDamietta University Department of Physics College of ScienceKing Khalid University Department of Physics College of Science for Girls in AbhaKing Khalid University

Modeling of instability and collision of nonlinear dust-acoustic（NDA） envelope solitons in strongly coupled dusty plasmas（SCDPs） is theoretically investigated. The SCDPs consists of strongly correlated negatively variable-charged dust grains and weakly correlated Boltzmann electrons and ions. Using the derivative expansion perturbation technique, a nonlinear Schr dinger-type（NLST） equation for describing the propagation of NDA envelope solitons is derived. Moreover,the extended Poincar′e–Lighthill–Kuo（ePLK） method is employed to deduce the analytical phase shifts and the trajectories after the collision of NDA envelope solitons. In detail, the results show that both modulation instability and phase shift after collision of NDA envelope solitons will modify with the increase in the effects of the viscosity, the relaxation time, and the dust charge fluctuation. Crucially, the modeling of dust-acoustic envelope solitons collision, as reported here, is helpful for understanding the propagation of NDA envelope solitons in strongly coupled dusty plasmas.

关键词： dust acoustic wave envelopes modulational instability head-on collision polarization effects

experimental determination of interfacial energies for Ag_2Al solid solution in the CuAl_2-Ag_2Al system

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Chinese Physics B 2009年第9期18卷 3952-3959页

作者： Ocak Y Akbulut S Keslioglu K Marasl1 N ad1rl1 e Kaya H Department of Physics Faculty of Arts and SciencesErciyes University Department of Physics Institute of Science and TechnologyErciyes University Department of Physics Faculty of Arts and SciencesNigde University Department of Science education Education FacultyErciyes University

The equilibrated grain boundary groove shapes of solid solution Ag2Al in equilibrium with an AI-Cu-Ag liquid were observed from a quenched sample with a radial heat flow apparatus. The Gibbs Thomson coefficient, solid liquid interfacial energy and grain boundary energy of the solid solution Ag2Al have been determined from the observed grain boundary groove shapes. The thermal conductivity of the solid phase and the thermal conductivity ratio of the liquid phase to solid phase for Ag2Al-28.3 at the %CuAl2 alloy at the melting temperature have also been measured with a radial heat flow apparatus and Bridgman type growth apparatus, separately.

关键词： solid-liquid interfaces metals and alloys surface energy thermal conductivity

Vapor transport growth of MoS2 nucleated on SiO2 patterns and graphene flakes

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Nano Research 2016年第11期9卷 3504-3514页

作者： Toma Stoica Mihai Stoica Martial Duchamp Andreas Tiedemann Siegfried Mantl Detlev Orutzmacher Dan Buca Beata e. Kardynal Peter Grunberg Institute 9 (PGI 9) andJARA-Fundamentals of Future Information Technologies Forschungszentrum Julich Julich 52425 Germany National Institute of Materials Physics Magurele Bucharest 077125 Romania Institute of Physical Chemistry 'llie Murgulescu' of the Romanian Academy Bucharest 060021 Romania Peter Grunberg Institute 5 (PGI 5) and JARA-Fundamentals of Future Information Technologies Forschungszentrum Julich Julich 52425 Germany

Vapor transport growth of atomically thin MoS2 layers on patterned substrates is investigated, as it is a step towards the self-aligned growth and formation of heterojunctions, which could be useful in future applications. enhanced formation of MoS2 flakes at the pattern edges is observed on both the substrates examined, namely, patterned thermal SiO2 on Si（100） and graphene flakes on SiO2. The diffusion driven growth leads to the formation of MoS2 monolayers （MLs） with sizes of tens of micrometers around the edges of SiO2 patterns. The growth mode and the optical quality of the MoS2 flakes can be controlled by varying the substrate temperature. Besides the lateral growth, 3R-type pyramids are obtained on prolonging the growth. Lateral MoS2-graphene heterostructures are obtained by using graphene flakes on SiO2 as a substrate.

关键词： MoS2 localized nucleation andgrowth graphene two-dimensional (2D)heterostructures

Improving BRICS’s public health and wellness through physical activity

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Journal of Sport and Health Science 2019年第6期8卷 503-504页

作者： Barbara e.Ainsworth Fuzhong Li J.Larry Durstine School of Kinesiology Shanghai University of SportShanghai 200438China College of Health Solutions Arizona State UniversityPhoenixAZ 85004USA Oregon Research Institute OR 97403USA Department of exercise Science The University of South CarolinaColumbiaSC 29208USA

In 2009,Professor Steven Blair predicted that physical inactivity would be the greatest public health issue of the 21st century.~1 A public health problem is one that affects the health,function,and well-being of a la... 详细信息

关键词： greatest function BRICS