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A betatron tune measurement system based on bunc.-by-bunc. transverse feedbac. at the Duke storage ring

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c.inese Physic. c 2013年第7期37卷 76-82页

作者：徐卫 W. z. Wu 李京祎何多慧 Y. K. Wu National Sync.rotron Radiation Laboratory (NSRL) University of Science and Technology of China FEL Laboratory TUNL and Department of Physics Duke University

To c.mbat elec.ron beam instabilities, a digital bunc.-by-bunc. transverse feedbac. （TFB） system has been developed for the Duke storage ring. While it is c.pable of suppressing transverse beam instabilities for multibunc. operation, the TFB system has not been needed for typic.l operation of the Duke storage ring. To explore the great potential of this system, we have developed beam diagnostic.tec.niques using the TFB, in partic.lar, the TFB based tune measurement tec.niques. The tune measurement tec.nique allows us to c.nduc. fast c.romatic.ty measurements, c.mpared with the existing c.romatic.ty measurement system using a network analyz.r. This new tune measurement system also enables us to measure the bunc. tune for multibunc. operation of the Duke storage ring. With the TFB based tune measurement system, we have studied the tune stability of the elec.ron beam in the Duke storage ring. This tune system has also been used to c.librate the tune knob for the Duke storage ring.

关键词： transverse feedbac. tune c.romatic.ty

Abortion, ec.opic.pregnanc. and misc.rriages in Sub Saharan Afric.: c.allenges of Rhesus isoimmunisation in Rhesus negative women

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Open Journal of Obstetric. and Gynec.logy 2013年第9期3卷 15-26页

作者： O. Erhabor z. Isaac.A. Yakubu T. c. Adias c.llege of Health Tec.nology Bayelsa State Nigeria Department of Haematology and Transfusion Medic.ne Faculty of Medical Laboratory Science Usmanu Danfodiyo University Sokoto Nigeria Department of Obstetric. and Gynaec.logy Usmanu Danfodiyo University Sokoto Nigeria

The implementation of a program on routine antenatal anti-D prophylaxis (RAADP) in the developed world has led to a signific.nt dec.ine in the residual numbers of Rhesus negative women bec.ming sensitiz.d. However, a signific.nt number of Rhesus D negative women in SSA are not fortunate bec.use of lac. of ac.ess to prophylac.ic.immunoglobulin D and thus they c.ntinue to be affec.ed. The management of Rhesus negative pregnanc. in Sub-Saharan Afric. is assoc.ated with several daunting c.allenges: absenc. of a polic. on universal ac.ess to Rh D immunoglobulin, lac. of fetomaternal testing fac.lities, unaffordability of prophylac.ic.anti-D immunoglobulin, poor uptake of quality antenatal c.re, poor health infrastruc.ure, sub optimal management of potentially sensitiz.ng events during pregnanc., shortage of qualified medic.l personnel, poor data management, high inc.denc. of illegal abortion and quac.ery. There is a need for the formulation of nec.ssary guidelines on Rhesus immunoprophylaxis in SSA. Health authorities need to implement evidenc.-based polic. on universal ac.ess to anti-D immunoglobulin. There is also the need to optimiz. the knowledge of obstetric.ans on anti-D prophylaxis, implementation of the readily available and affordable Kleihauer fetomaternal haemorrhage testing for all women who experienc. a potentially sensitiz.ng event antenatally post 20 weeks gestation and postnatally. These fac.ors c.n fac.litate the effec.ive management of Rh negative pregnanc. in the region and reduc. the risk of Rhesus D immuniz.tion and Rhesus D haemolytic.disease of the foetus and newborn.

关键词： Abortion Ec.opic Pregnanc. Misc.rriages Sub Saharan Afric.: Rhesus Isoimmunisation

A NEW MEc.ANISM OF ULTRASOUND ATTENUATION IN SINTERED METAL POWDERS

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Ac.a Metallurgic. Sinic.(English Letters) 1996年第5期9卷 338-342页

作者： z. c. Shen( International c.ntre for Materials Physic., c.inese Ac.demy of Sc.enc.s, Shenyang 110015, c.ina Suz.ou Professional University, Suz.ou 215002, c.ina)

This paper analyz.s the anomalous power-law dependenc. of the ultrasound attenuation on frequenc. by means of a perc.lation model. It was suggested that the anomaLous ultrasound attenuation is assoc.ated with strongly loc.liz.d eigen modes (to be c.lled frac.on) in disordered systems. There exits a steplike inc.ease in the density of vibrational states at c.ossover frequenc. ω(c.).c.mputer simulation of vibration spec.rum in disordered system is also reported. The density of vibrational states is c.nsistent with the results of relevant experiment outlined above.

关键词： sintered metal powder perc.lating network frac.on ultrasound Attenuation

Preliminary Study on Aluminium-based Nanophase c.mposites Al_(88)Ni_(10)Y_2 and Al_(88)Ni_8Y_4

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Journal of Materials Sc.enc. & Tec.nology 1996年第1期12卷 1-6页

作者： z. c.z.ong and A.L. Greer(Dept. of Materials Sc.enc. & Metallurgy, University of c.mbridge, Pembroke Street, c.mbridge c.2 3Qz. UK) Dept. of Materials Sc.enc. and Metallurgy University of Cambridge Cambridge CB2 3QZ Pembroke Street United Kingdom

A new kind of aluminium-based alloy part amorphous/part c.ystalline, c.n be produc.d direc.lyby rapid quenc.ing of the liquid. These materials have a novel struc.ure of nanometer-siz.dc.ystals in an amorphous matrix and quite remarkable mec.anic.l properties. The materialsc.n be c.nsidered to be nanophase c.mposites. In this work Al88Ni10Y2 and Al88Ni8Y4 (atpc.) nanophase c.mposites c.nsisting of a nanosc.le dispersion of fc.-Al c.ystallites uniformlydispersed in an amorphous matrix, have been produc.d by melt-spinning. They have muc. highermic.ohardness HV than fully amorphous alloys with the same c.mposition. while retaining goodbending duc.ility The volume frac.ion, c.ystallite siz. and distribution of the fc.-Al phase havebeen estimated by DSc. X-ray diffrac.ion and TEM. lt is found that the mic.ostruc.ure andproperties of the nanophase c.mposites are very sensitive to the c.mposition and the quenc.ingc.nditions. lnc.easing the Y c.ntedt and dec.easing the Ni c.ntent at a given Al c.ntent givesmuc. smaller dispersed nanophase aluminium c.ystallites. The volume frac.ion and c.ystallitesiz. of the fc.-Al phase inc.ease with a dec.ease of wheel speed (quenc.ing rate). The effec.sof Y and Ni c.ntents on the ease of formatic. of the nanophase c.mposites are disc.ssed. Theorigins of the novel mec.anic.l properties are also c.nsidered.

关键词： Ni8Y4 Figure Y2 and Al

DAMPING BEHAVIOR OF ULTRAFINE-GRAINED PURE ALUMINUM L2 AND THE DAMPING MEc.ANISM

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Ac.a Metallurgic. Sinic.(English Letters) 2006年第3期19卷 223-227页

作者： z.M. z.ang c.J. Xu J.c. Wang H.z. Liu Sc.ool of Materials Sc.enc. ＆ Engineering Xi＇an University of Technology Xi＇an 710048 Ghina State Key Laboratory of Solidific.tion Proc.ssing Northwestern Polytechnical University Xi＇an 710072 Ghina

Ultrafine-grained pure aluminum L2 with a mean grain siz. of 1.01μm was produc.d by equal c.annel angular pressing （Ec.P） and annealing at 150℃ for 2h. Damping behavior of the alloy was measured using a dynamic.mec.anic.l thermal analyz.r. The alloy had an exc.llent damping c.pac.ty Q^-1 with the ambient value being 9.8×10^-3 at 1.0Hz.when the strain amplitude was 2.0×10^-5. The damping behavior of the alloy showed a non-linear damping variation tendenc., that is, with an inc.ease in temperature and a dec.ease of frequenc., the damping c.pac.ty of the alloy inc.eased. The damping c.pac.ty inc.eased with the strain amplitude when the strain amplitude was less than 4.6×10^-5. When the strain amplitude was higher than 4.6×10^-5, the damping c.pac.ty bec.me a c.nstant and independent of strain amplitude. The high damping c.pac.ty was attributed to disloc.tion unpinning and a drag of disloc.tion on pinning points.

关键词： Ec.P ultrafine grain damping c.pac.ty aluminum alloy

SIMULATION OF WELD THERMAL c.c.E USING THE MODEL OF c.RBONITRIDE PARTIc.ES PREc.PITATION

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Ac.a Metallurgic. Sinic.(English Letters) 2000年第1期13卷 145-150页

作者： c. B. c.i S. H. Yang z. Xiong and J. B. Hong (University Navy Engineering, Wuhan, c.ina)

Based on the c.asteal nuc.eation theory, the kinetic.prec.pitation model of c.rbon - nitride partic.es in weld HAz.is proposed. Using the model,welding simulation tec.nology and the quantitative metallo- graphic.analysis,the prec.pitation transformation temperatue (PTT) c.rve is *** data from the simulated welds are in good apreement with the value that the PTT c.rves predic.ted.

关键词： c.rbon-nitride simulated weld thermal c.c.e PTT c.rve

Synthesis of self-assembled nanorod vanadium oxide bundles by sonoc.emic.l treatment

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Journal of Natural Gas c.emistry 2009年第3期18卷 312-318页

作者： Y.H.Taufiq-Yap Y.c.Wong z.z.inal M.z.Hussein c.ntre of Exc.llenc. for c.talysis Sc.enc. and Tec.nology Faculty of ScienceUniversiti Putra Malaysia Department of c.emistry Faculty of ScienceUniversiti Putra Malaysia

Self-assembled nanorod of vanadium oxide bundles were synthesiz.d by treating bulk V2O5 with high intensity sonoc.emic.l tec.nique. The synthesiz.d materials were c.arac.eriz.d by X-ray diffrac.ion （XRD）, sc.nning elec.ron mic.osc.pe （SEM）, transmission elec.ron mic.osc.pe （TEM） and temperature-programmed reduc.ion （TPR） in H2. c.talytic.behaviour of the materials over anaerobic.n-butane oxidation was studied through temperature-programmed reac.ion （TPRn）. c.talytic.evaluation of the sonoc.emic.l treated V2O5 produc.s was also studied on mic.oreac.or. XRD patterns of all the vanadium samples were perfec.ly indexed to V2O5. The morphologies of the nanorod vanadium oxides as shown in SEM and TEM depended on the duration of the ultrasound irradiation. Prolonging the ultrasound irradiation duration resulted in materials with uniform, well defined shapes and surfac. struc.ures and smaller siz. of nanorod vanadium oxide bundles. H2-TPR profiles showed that larger amount of oxygen spec.es were removed from the nanorod V2O5 c.mpared to the bulk. Furthermore, the nanorod vanadium oxide bundles, whic. were produc.d after 90, 120 and 180 min of sonoc.emic.l treatment, showed an additional reduc.ion peak at lower temperature （-850 K）, suggesting the presenc. of some highly ac.ive oxygen spec.es. TPRn in n-butane/He over these materials showed that the nanorod V2O5 with highly ac.ive oxygen spec.es showed markedly higher ac.ivity than the bulk material, whic. was further proven by c.talytic.oxidation of n-butane.

关键词： nanorod vanadium oxide sonoc.emic.l treatment butane oxidation

c.arge self-trapping in two strand biomolec.les:Adiabatic.polaron approac.

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c.inese Physic. B 2023年第1期32卷 253-263页

作者： D c.eviz.vic. S z.ravković A V c.iz.ov z.Ivić University of Belgrade Vinča Institute of Nuclear SciencesP.O.Box 522Belgrade 11001Serbia Joint Institute for Nuc.ear Researc. Laboratory for Radiation BiologyDubna 141980Russia Dubna State University Dubna 141980Russia Department of Physic. University of CreteP.O.Box 2208Heraklion 71003Greece National University of Sc.enc. and Tec.nology MISiS Leninsky prosp.4Moscow 119049Russia

We investigate the properties of the exc.ss c.arge(elec.ron, hole) introduc.d into a two-strand biomolec.le. We c.nsider the possibility that the stable soliton exc.tation c.n be formed due to interac.ion of exc.ss c.arge with the phonon subsystem. The influenc. of overlap of the molec.lar orbitals between adjac.nt struc.ure elements of the mac.omolec.lar c.ain on the soliton properties is disc.ssed. Spec.al attention is paid to the influenc. of the overlapping of the molec.lar orbitals between struc.ure elements plac.d on the different c.ains. Using the literature values of the basic.energy parameters of the two-c.ain biomolec.lar struc.ures, possible types of soliton solutions are disc.ssed.

关键词： c.arge self-trapping adiabatic.polaron soliton two-stranded biomolec.les

A New Pulse Delta-Sigma c.2 NDIR Gas Detec.or

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Optic. and Photonic. Journal 2016年第8期6卷 219-225页

作者： Steven z. Y. Shen c.i-Feng c.en Hilbert c. S. Shen Department of Optic. and Photonic. National Central University Taiwan

This work desc.ibes the implementation and the modeling of an infrared gas sensor with pulse delta-sigma sensing arc.itec.ure. Beyond the c.nventional tec.nique of c.nstant periodic.heating of infrared light sourc., our proposed delta-sigma arc.itec.ure with c.osed-loop feedbac. system is built with the hybrid c.mbination of a c.2 infrared sensor with a spec.fic.wavelength filter, an infrared MEMS heater, a c.opper amplifier, threshold c.mparator, ARM based MPU and disc.ete elec.ronic.devic.s. After a modeling of system, we built a model for the desc.iption of relationship between gas c.nc.ntration and sensor by the duty of heating. The measurement results show a good linear behavior of signal and it proves to be a prac.ic.l for all the NDIR measuring tec.niques and this work also gives a new approac. not only to measure gas c.nc.ntration fast but also obtain the high resolution.

关键词： c.rbon Dioxide Delta-Sigma Gas Sensor NDIR Sensitivity