We report on the generation of a high energy and long pulse for pumping optical parametric chirped-pulse amplification (OPCPA) by a high-birefringence photonic crystal fibre (HB-PCF) and a laser-diode-pumped regen...
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We report on the generation of a high energy and long pulse for pumping optical parametric chirped-pulse amplification (OPCPA) by a high-birefringence photonic crystal fibre (HB-PCF) and a laser-diode-pumped regenerative chirped pulse amplifier. Using the femtosecond pump pulse centred at 815 nm, a 1064 nm soliton pulse is produced in the HB-PCF. After injecting it into an Nd:YAG regenerative amplifier with the glass etalons, a narrow-band amplified pulse with an energy of -4 mJ and a duration of 235 ps is achieved at a repetition rate of 10 Hz, which is suitable for being used as a pump source in the 800 nm OPCPA system.
In this work,NH_(2)-substituted oxazoles and NO_(2)/NF_(2)/NHNO_(2)-substituted ethylenes/acetylenes were designed and used as dienes and dienophiles,respectively,in order to develop new bridge-ring insensitive high e...
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In this work,NH_(2)-substituted oxazoles and NO_(2)/NF_(2)/NHNO_(2)-substituted ethylenes/acetylenes were designed and used as dienes and dienophiles,respectively,in order to develop new bridge-ring insensitive high energy compounds through the Diels-Alder reaction between *** reaction type,reaction feasibility and performance of reaction products were investigated in detail *** results showed that dienes most possibly react with dienophiles through the HOMO-diene controlled normal Diels-Alder reaction at relatively low energy *** could react with the designed dienes much more easily than other dienophiles,and was employed to further design 29 new bridge-ring energetic *** to high heat of formation,density and oxygen balance,all designed bridge-ring energetic compounds have outstanding detonation performance,16 of them have higher energy than HMX(1,3,5,7-tetranitro-1,3,5,7-tetrazocine)and 2 others even possess comparative energy with the representative of high energy compounds CL-20(2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane).The predicted average h50 value of these bridge-ring energetic compounds is 83 cm,showing their low impact *** NH2 groups could obviously impel the proceeding of Diels-Alder reactions,but would slightly decrease the energy and sensitivity *** all,the new designed bridge-ring compounds have both high energy and low sensitivity,and may be produced through Diels-Alder reactions at relatively low energy *** paper may be helpful for the theoretical design and experiment synthesis of new advanced insensitive high energy compounds.
When a high energy nanosecond(ns)laser induces breakdown in the air,the plasma density generated in the rarefied atmosphere is much smaller than that at normal *** is associated with a relatively lower absorption coef...
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When a high energy nanosecond(ns)laser induces breakdown in the air,the plasma density generated in the rarefied atmosphere is much smaller than that at normal *** is associated with a relatively lower absorption coefficient and reduces energy loss of the laser beam at low *** this paper,the general transmission characterizations of a Joule level 10 ns 1064 nm focused laser beam are investigated both theoretically and experimentally under different *** evolution of the electron density(n_(e)),the changes in electron temperature(T_(e))and the variation of laser intensity(I)are employed for numerical analyses in the simulation *** experiments,four optical image transfer systems with focal length(f)of 200 mm are placed in a chamber and employed to focus the laser beam and produce plasmas at the *** results suggest that the transmittance increases obviously with the decreasing pressure and the plasma channels on the transmission path can be observed by the *** simulation results agree well with the experimental *** numerical model presents that the maximum n_e at the focus can reach 10^(19)cm^(-3),which is far below the critical density(n_(c)).As a result,the laser beam is not completely shielded by the plasmas.
Insulating ceramics are applied to modern manufacturing industries for their improved material *** they are the difficult-to-machine materials because of their high rigidity,high brittleness and non-electrical conduct...
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Insulating ceramics are applied to modern manufacturing industries for their improved material *** they are the difficult-to-machine materials because of their high rigidity,high brittleness and non-electrical conductivity.A new method which employs a high energy capacitor for electric discharge machining of insulating ceramics efficiently is presented in this paper,and the single discharge experiments have been carried *** process uses the high voltage,large capacitor and high discharge energy,it is able to effectively machine insulating ceramics,and the single discharge crater volume of insulating ceramics can reach 17.63 *** effects of polarity,peak voltage,capacitance,current-limiting resistance,tool electrode feed,tool electrode section area and assisting electrode thickness on the process performance such as the single discharge crater volume,the tool wear ratio and the assisting electrode wear ratio have been *** microstructure of the discharge crater is examined with a scanning electron microscope(SEM).The results show that the discharge craters have sputtering appearance,the insulating ceramic materials are mostly removed by spalling,in the center region of the discharge some materials are removed by melting and vaporization,and the material removal is enhanced with the machining parameters increasing.
作者:
Wei WangINPAC
Shanghai Key Laboratory for Particle Physics and Cosmology MOE Key Laboratory for Particle Physics Astrophysics and Cosmology School of Physics and Astronomy Shanghai JiaoTong University Shanghai 200240 China
I discuss the production mechanism of hidden-flavored hadrons at high energy. Using e+e-collisions and light-meson pair production in high energy exclusive processes, I demonstrate that hidden quark pairs do not nece...
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I discuss the production mechanism of hidden-flavored hadrons at high energy. Using e+e-collisions and light-meson pair production in high energy exclusive processes, I demonstrate that hidden quark pairs do not necessarily participate in short-distance hard scattering. Implications are then explored in a few examples. Finally, I discuss the production mechanism of X(3872) in hadron collisions, where some misunderstandings have arisen in the literature.
We report on frequency doubling of high-energy,high repetition rate ns pulses from a cryogenically gas cooled multi-slab ytterbium-doped yttrium aluminum garnet laser system,Bivoj/DiPOLE,using a type-I phase matched l...
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We report on frequency doubling of high-energy,high repetition rate ns pulses from a cryogenically gas cooled multi-slab ytterbium-doped yttrium aluminum garnet laser system,Bivoj/DiPOLE,using a type-I phase matched lithium triborate *** achieved conversion to 515 nm with energy of 95 J at repetition rate of 10 Hz and conversion efficiency of 79%.high conversion efficiency was achieved due to successful depolarization compensation of the fundamental input beam.
A diode pumped high energy Yb∶YAG rod regenerative amplifier was demonstrated with a maximum energy of22.3 m J,excellent energy stability(~0.8%root mean square),and beam quality(M2<1.2)at 10 Hz repetition *** the bes...
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A diode pumped high energy Yb∶YAG rod regenerative amplifier was demonstrated with a maximum energy of22.3 m J,excellent energy stability(~0.8%root mean square),and beam quality(M2highest energy so far obtained by a Yb∶YAG rod regenerative amplifier.
The deuteron breakup on heavy targets has been investigated in the framework of an improved quantum molecular dynamics model,focusing on the production of neutrons near zero *** experimental differential cross section...
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The deuteron breakup on heavy targets has been investigated in the framework of an improved quantum molecular dynamics model,focusing on the production of neutrons near zero *** experimental differential cross sections of neutron production in the 102 MeV d+C reactions were reproduced by *** on the consistency between the model prediction and experiment,the feasibility of producing a neutron beam through the breakup of deuteron on a carbon target was *** of the nucleon Fermi motion inside the deuteron,the energy spectrum of the inclusive neutron near 0°in the laboratory exhibits considerable energy broadening in the main peak,whereas the long tail on the low-energy side is *** coincidentally measuring the accompanying deuteron breakup proton,the energy of the neutron can be tagged with an intrinsic uncertainty of approximately 5%(1σ).The tagging efficiency of the accompanying proton on the forward-emitted neutron can reach 90%,which ensures that the differential cross section in the(d,np)channel remains two orders higher than that in(p,n)after considering the measurement of accompanying *** enables the application of a well-defined energy neutron beam in an event-by-event scheme.
Increasing the energy density of conventional lithium-ion batteries(LIBs)is important for satisfying the demands of electric vehicles and advanced *** is considered as one of the most-promising anodes to replace the t...
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Increasing the energy density of conventional lithium-ion batteries(LIBs)is important for satisfying the demands of electric vehicles and advanced *** is considered as one of the most-promising anodes to replace the traditional graphite anode for the realization of high-energy LIBs due to its extremely high theoretical capacity,although its severe volume changes during lithiation/delithiation have led to a big challenge for practical *** contrast,the co-utilization of Si and graphite has been well recognized as one of the preferred strategies for commercialization in the near *** this review,we focus on different carbonaceous additives,such as carbon nanotubes,reduced graphene oxide,and pyrolyzed carbon derived from precursors such as pitch,sugars,heteroatom polymers,and so forth,which play an important role in constructing micrometersized hierarchical structures of silicon/graphite/carbon(Si/G/C)composites and tailoring the morphology and surface with good structural stability,good adhesion,high electrical conductivity,high tap density,and good interface chemistry to achieve high capacity and long cycling stability *** first discuss the importance and challenge of the co-utilization of Si and ***,we carefully review and compare the improved effects of various types of carbonaceous materials and their associated structures on the electrochemical performance of Si/G/C *** also review the diverse synthesis techniques and treatment methods,which are also significant factors for optimizing Si/G/C ***,we provide a pertinent evaluation of these forms of carbon according to their suitability for *** also make far-ranging suggestions with regard to the selection of proper carbonaceous materials and the design of Si/G/C composites for further development.
A high-energy,alignment-insensitive,injection-seeded Q-switched Ho:yttrium aluminum garnet(YAG)singlefrequency laser is *** the slave Q-switched laser and the seed laser are Ho:YAG ring lasers based on a pair of corne...
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A high-energy,alignment-insensitive,injection-seeded Q-switched Ho:yttrium aluminum garnet(YAG)singlefrequency laser is *** the slave Q-switched laser and the seed laser are Ho:YAG ring lasers based on a pair of corner cubic *** seed laser has an available power of 830 mW at 2096.667 *** 100 Hz,the Q-switched Ho:YAG laser provides a single-frequency pulsed output using injection-seeded *** 7.3 mJ single-frequency pulse energy from the slave laser has a pulse width of 161.2 ns and is scaled to 33.3 mJ after passing through the Ho:YAG single-pass *** to the measurement results of the heterodyne beating technique,the single-frequency pulse has a half-width of 4.12 MHz.
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