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We present three possible design options of laser plasma acceleration (LPA) for reaching a 100-GeV level energy by means of a multi-petawatt laser such as the 3.5-kJ, 500-fs PETawatt Aquitane Laser (PETAL) at French Alternative Energies and Atomic Energy Commission (CEA). Based on scaling of laser wakefield acceleration in the quasi-linear regime with the normalized vector potential a0 =1.4(1.6), acceleration to 100 (130) GeV requires a 30-m-long plasma waveguide operated at the plasma density n e ≈ 7×10 15 cm-3 with a channel depth Δn/ne = 20%, while a nonlinear laser wakefield accelerator in the bubble regime with a0≥2 can reach 100 GeV approximately in a36/a0-m-long plasma through self-guiding. The third option is a hybrid concept that employs a ponderomotive channel created by a long leading pulse for guiding a short trailing driving laser pulse. The detail parameters for three options are evaluated, optimizing the operating plasma density at which a given energy gain is obtained over the dephasing length and the matched conditions for propagation of relativistic laser pulses in plasma channels, including the self-guiding. For the production of high-quality beams with 1%-level energy spread and a 1π-mm-mradlevel transverse normalized emittance at 100-MeV energy, a simple scheme based on the ionization-induced injection mechanism may be conceived. We investigate electron beam dynamics and effects of synchrotron radiation due to betatron motion by solving the beam dynamics equations on energy and beam radius numerically. For the bubble regime case with a0=4, radiative energy loss becomes 10% at the maximum energy of 90 GeV. 相似文献
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基于Brenner的REBO势函数,利用分子动力学方法模拟了含氢量不同的类金刚石薄膜的纳米压痕过程,依据得到的加载卸载曲线,计算了薄膜的刚度、硬度以及弹性模量.结果表明:类金刚石薄膜的硬度由氢含量和sp3键含量两个因素共同决定;当薄膜中氢含量小于39% 时,薄膜硬度主要取决于sp3键含量,sp3键越多,硬度越高;当薄膜中氢含量达到52%,薄膜硬度则显著下降,此时氢的作用占据主导地位.
关键词:
类金刚石薄膜
分子动力学模拟
纳米压痕
硬度 相似文献
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The β- decaying γ scheme of the neutron-rich nuclide 208Hg has been determined for the first time.The 208 Hg was produced in multi-nucleon transfer reaction taking place in the bombardment of 18O-beam on natural lead target,and the Hg-element products were sepaated with a gas-thermochromatography technique.The γ-ray single and γ-γ coincident spectra were measured.A partial 208 Hg γ scheme was proposed.Twenty-six γ rays were assigned to follow the β- decay of 208Hg.At the same time,a new level structure of the daughter nucleus 208 T1 was constructed,in which three new levels at 1.725MeV.1.652MeV,and 1.362MeV were affirmed.The experimental 208Tl level structure was compared with a shell-model calculation. 相似文献
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本文用量热滴定研究了N-苄基-单氮杂-15-冠-5与稀土(Ⅲ)硝酸盐(La,Ce,Pa,Nd,Sm,En,Gd,Tb,Dy,Ho,Er,Yb)和N-苄基-单氮杂-18-冠-6与稀土(Ⅲ)硝酸盐(La和Ce)在无水乙腈溶液中,298.15K时配位作用的热力学性质、化学计量法表明,所有稀土硝酸盐均与臂式冠醚形成1:1配合物.实验中,由联接的计算机直接算出了配合物 的稳定常数和配位反应的热焓,进而算出了配位自由能和配位熵.从热力学的观点,讨论了冠醚环的尺寸效应、空间构型等对配位稳定性的影响. 相似文献
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该文水解合成并通过煅烧改变晶型,获得了金红石和锐钛矿两种晶型混合的二氧化钛纳米粒子。利用紫外可见分光光度法(UV-Vis)、激光粒度分析(LPSA)、X射线多晶衍射分析(XRD)和冷场发射扫描电镜(SEM)等方法对样品进行了表征。制备了以氧化铟锡(ITO)玻璃为基底的纳米TiO2修饰电极,并研究了晶型对鲁米诺电化学发光(ECL)的增敏作用的影响。结果表明,当粒径较小,经650℃煅烧处理形成混晶时,纳米TiO/ITO修饰电极对鲁米诺电化学发光的增敏效果最明显,为裸电极的7.5倍。 相似文献