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1.
给出了高能脉冲X射线能谱测量的基本原理及实验结果.采用Monte-Carlo程序计算了高能光子在能谱仪中每个灵敏单元内的能量沉积,利用能谱仪测量了"强光Ⅰ号"加速器产生的高能脉冲X射线不同衰减程度下的强度,求解得到了具有时间分辨的高能脉冲X射线能谱,时间跨度57ns,时间步长5ns,光子的最高能量3.0MeV,平均能量1.04MeV,能量在0.2—0.9MeV之间的光子数目最多,占46.5%.也利用二极管的电压电流波形理论计算了光子的能谱,并与利用能谱仪测得的能谱进行了比较,两种方法所得结果基本一致. 相似文献
2.
Since the energy density of high energy laser can be extremely high and destructive, it is difficult to directly measure the laser energy with custom methods. A volume absorption method directly using water as absorption substance is introduced. In the energy meter, water is pumped into an absorption cavity sealed by a quartz window, and energy increment of water by laser is calculated. The new energy meter has excellent power and energy linearity and is almost not affected by power, energy and flow, its relative deviation to norm middle-power energy meter is 1.9 %, which infers that the new energy meter can measure higher laser energy and maintain higher precision as well. 相似文献
3.
根据原电子射程表达式和金属的有效真二次电子发射系数表达式,推导出金属的高能有效真二次电子发射系数与入射能量、能量幂次的关系式;并根据金属的高能有效真二次电子发射系数与金属的高能二次电子发射系数的关系,推导出金属的高能二次电子发射系数与入射能量、能量幂次的关系式。用实验数据计算出高能原电子轰击在金或银上时原电子入射能量幂次n,采用实验数据证实高能二次电子发射系数与原电子入射能量和能量幂次三者的关系,对结果进行讨论并得出结论:当高能原电子轰击在同一块金属上时,高能二次电子发射系数与原电子入射能量的n-1次幂之积近似为一常数。 相似文献
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5.
The process of amorphous silica clusters impact on a crystal silicon substrate is studied by molecular dynamics simulation,
focusing on the energy transfer between clusters and the substrate under different impact conditions such as cluster size,
impact velocity, and incidence angle. The impact process is divided into cluster deformation stage, cluster resilience stage,
and cluster rebound stage according to the courses of energy change during the impact process. The simulation elucidates that
the time of impact process of every cluster is only related to cluster size and is independent of impact velocity and incidence
angle. The translational energy loss of the cluster and the potential energy increment of the substrate during cluster deformation
stage, and the dissipation energy of system are independent of cluster size under the same impact energy and incidence angle.
And the translational energy loss of the cluster during cluster rebound stage changes from energy absorption to energy release
after the incidence angle becomes more than 60°. The rotational energy of the cluster may be omitted when the incidence angle
is less than 15°. The ratios of the rotational energy increment of the cluster, the kinetic energy increment, and the potential
energy increment of the substrate to the translational energy loss of the cluster are obviously influenced by impact conditions.
And the ratios of the increment of the other categories of energy to the translational energy loss of the cluster are not
sensitive to impact conditions. 相似文献
6.
In this paper, the principle of adjusting the proton energy from the linear accelerator with energy adjusting cavities is proposed. The requirements to energy adjusting cavities for tuning the proton energy efficiently and continually are studied. The energy range adjustable and the energy spread are calculated for 35 MeV proton linac which is in the course of construction at the Institute of High Energy Physics, as an example. The energy spread as a function of electric parameters of energy adjusting cavities are also discussed. A specific and economical method to supply rf power to energy adjusting cavities is presented. 相似文献
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8.
高能激光能量计校准方法研究 总被引:4,自引:3,他引:1
给出了一种绝对式高能激光能量计光电校准方法.该方法以大功率灯作为校准光源,通过测量灯两端的电压以及电流获得电能值,去掉灯所消耗的热能,得到灯所发出的光能.所设计平板能量计将大功率灯密封在高能激光能量计内,光能全部被能量计吸收.根据能量计输出值以及光能值便可实现能量计光电校准.结果表明,能量计光电校准不确定度约为1.5%. 相似文献
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10.
理论分析了收集极中运动电子的失能机制和电子能量对电子束能量沉积的影响,用蒙特卡罗方法计算了不同能量下入射电子的能量沉积分布,分析了电子能量对电子束在收集极中能量沉积的影响,并据此提出了提高收集极耐电子束轰击能力的两种途径。结果表明:激发和电离是收集极中入射电子的主要失能机制;电子的能量越高,在材料中的穿透能力越强,收集极中被收集电子束的最大能量沉积密度越低。综合考虑束流密度分布对能量沉积的影响,可通过两种途径来提高收集极耐电子束轰击的能力:一是通过结构设计增大电子束的收集面积,减小收集极上被收集电子束的束流密度;二是设计高阻抗器件,增大被收集电子束的电子能量,减小收集极上被收集电子束的束流密度。 相似文献
11.
为了研究 MeV能量离子在生物样品中的能量损失与能量离散, 分别使用1.0, 1.8和2.8 MeV质子和4.5 MeV氦离子分别辐照不同质量厚度的洋葱内表皮膜。 当质子穿过该生物样品后, 可以利用透射能谱测量透射离子的能量损失和能量离散。 实验结果显示, 在以上的生物样品中, MeV能量离子的能量损失值和TRIM程序模拟的结果相吻合, 但是透射离子的能量离散值却与TRIM程序模拟结果有很大的不同。 结合生物样品的结构不均匀的特性, 对Bohr能量离散理论进行了修正, 并发现修正后的Bohr能量离散理论计算结果与实验值符合得很好。 相似文献
12.
基于靶背鞘层加速机制(TNSA)产生的质子束具有宽能谱的特性,限制了其应用范围。为了产生准单能质子束,研究了基于直线加速器射频腔结构的质子能谱优化方法。在给定射频腔电压和频率情况下,计算了腔间距随优化能量的变化关系,并针对不同优化能量设计了不同大小的腔间距和腔数。在给定腔数情况下,发现只在某个能量附近可以获得单能性最好的单能峰。对能量接受范围进行了分析,要实现最终2%的能散,进入射频腔的质子束能散不能大于15%,并分析了射频腔频率对能量接受范围的影响。最后对PIC模拟得到的半高全宽为15%的一个能谱进行优化,获得了谱宽小于2%的准单色质子能谱。
. 相似文献
13.
采用线性组合算符法和幺正变换法研究温度对抛物型量子阱中极化子基态能和基态结合能的影响. 通过理论推导得到极化子基态能和基态结合能的表达式. 结合量子统计力学中平均声子数的表达式, 得到极化子基态能量和基态结合能与温度的函数关系. 在不同温度下, 分别讨论了极化子基态能量和基态结合能与电子-声子耦合强度和阱宽的关系, 阱深取不同值时讨论了极化子基态能和基态结合能随温度的变化规律. 计算结果表明, 极化子的基态能量和基态结合能都是温度的递增函数. 相似文献
14.
Electric ignition energy evaluation and the energy distribution structure of energy released in electrostatic discharge process
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Ignition energy is one of the important parameters of flammable materials, and evaluating ignition energy precisely is essential to the safety of process industry and combustion science and technology. By using electric spark discharge test system, a series of electric spark discharge experiments were conducted with the capacitor-stored energy in the range of 10 J, 100 J, and 1000 J, respectively. The evaluation method for energy consumed by electric spark, wire, and switch during capacitor discharge process has been studied respectively. The resistance of wire, switch, and plasma between electrodes has been evaluated by different methods and an optimized evaluation method has been obtained. The electric energy consumed by wire, electric switch, and electric spark-induced plasma between electrodes were obtained and the energy structure of capacitor-released energy was analyzed. The dynamic process and the characteristic parameters(the maximum power, duration of discharge process) of electric spark discharge process have been analyzed. Experimental results showed that, electric spark-consumed energy only accounts for 8%–14% of the capacitor-released energy. With the increase of capacitor-released energy, the duration of discharge process becomes longer, and the energy of plasma accounts for more in the capacitor-released energy. The power of electric spark varies with time as a damped sinusoids function and the period and the maximum value increase with the capacitor-released energy. 相似文献
15.
Masahiro Hotta 《Physics letters. A》2008,372(35):5671-5676
In this Letter, a protocol called quantum energy distribution (QED) is proposed in which multi-parties can simultaneously extract positive energy on average from spin chains by use of common secret keys shared by an energy supplier. QED is robust against impersonation. An adversary, who does not have common secret keys and attempts to get energy, cannot obtain but give energy to spin chains. Total amount of energy transfer gives a lower bound of residual energy of a local cooling process by the energy supplier. 相似文献
16.
This paper establishes a new formulation of the energy exchanges between the different parts of total energy. The decomposition uses the Reynolds averaging. This leads to a ternary decomposition of kinetic energy into the turbulence kinetic energy, the mean kinetic energy and the mixed kinetic energy, acting as an exchange term between the mean and turbulent motion. The formulation is then extended to distinguish a mean and fluctuating density part of each part of total energy. The formulation thus includes the mean density turbulence kinetic energy, product of the mean density and the half-trace of the velocity fluctuation correlation tensor. Its evolution equation is given in the spectral domain. 相似文献
17.
采用微正则系综理论和嵌入原子模型计算了原子数为16-152之间7个Aun团簇碰撞合并过程。结果表明:碰撞能量大于0.3eV时,团簇处于熔融态,碰撞能量是合并过程的主导因素,碰撞能量小于0.3eV时,团簇处于凝固态,碰撞能量和结合能共同影响合并过程;碰撞能量小于0.1eV时,在结合能作用下,团簇结构随碰撞能量增加发生变化,其中壳层结构势能较低,稳定性较好。 相似文献
18.
In the classical
Peierls--Nabarro (P-N) theory of dislocation,
there is a long-standing contradiction that the stable configuration
of dislocation has maximum energy rather than minimum energy. In
this paper, the dislocation energy is calculated rigorously in the
context of the full lattice theory. It is found that besides the
misfit energy considered in the classical P-N theory, there is an
extra elastic strain energy that is also associated with the
discreteness of lattice. The contradiction can be automatically
removed provided that the elastic strain energy associated with the
discreteness is taken into account. This elastic strain energy is
very important because its magnitude is larger than the misfit
energy, its sign is opposite to the misfit energy. Since the elastic
strain energy and misfit energy associated with discreteness cancel
each other, and the width of dislocation becomes wide in the lattice
theory, the Peierls energy, which measures the height of the
effective potential barrier, becomes much smaller than that given in
the classical P-N theory. The results calculated here agree with
experimental data. Furthermore, based on the results obtained, a
useful formula of the Peierls stress is proposed to fully include
the discreteness effects. 相似文献
19.
The Acoustic Energy Flow Boundary Element Method (AEFBEM) is developed to predict the acoustic energy density and intensity of an engineering system. Up to now, the acoustic energy flow model has been used only for analysis of high frequencies or radiation noise because of plane wave and far-field assumptions. In this research, a new energy flow governing equation that can consider the near field acoustic energy term and spherical wave characteristics is derived successfully to predict the acoustic energy density and intensity of a system in the medium-to-high frequency range. A near field term of acoustic energy in spherical coordinate is added to the relationship between energy density and energy flow. But with the far-field assumption, this term vanishes, so the relationship between energy density and energy flow becomes the same as that of the plane wave. By considering the near field energy term without far-field assumption, the energy density at medium frequencies can be estimated. However, the governing equation has to be numerically manipulated for use in the analysis of complex structures; therefore, the Boundary Element Method (BEM) is implemented. AEFBEM is a numerical analysis method formulated by applying the boundary element method to an acoustic energy flow governing equation. It is very powerful in predicting the acoustic energy density and intensity of complex structures in medium-to-high frequency ranges, and can analyze interior noise and radiating sound. To verify its validity, several numerical results are provided. BEM and AEFBEM were compared with respect to energy density, and the results from both methods were similar. 相似文献
20.
An energy transfer mechanism in high-temperature supersonic turbulent flow for variable specific heat (VSH) condition through turbulent kinetic energy (TKE), mean kinetic energy (MKE), turbulent internal energy (TIE) and mean internal energy (MIE) is proposed. The similarities of energy budgets between VSH and constant specific heat (CSH) conditions are investigated by introducing a vibrational energy excited degree and considering the effects of fluctuating specific heat. Direct numerical simulation (DNS) of temporally evolving high-temperature supersonic turbulent channel flow is conducted at Mach number 3.0 and Reynolds number 4800 combined with a constant dimensional wall temperature 1192.60 K for VSH and CSH conditions to validate the proposed energy transfer mechanism. The differences between the terms in the two kinetic energy budgets for VSH and CSH conditions are small; however, the magnitude of molecular diffusion term for VSH condition is significantly smaller than that for CSH condition. The non-negligible energy transfer is obtained after neglecting several small terms of diffusion, dissipation and compressibility related. The non-negligible energy transfer involving TIE includes three processes, in which energy can be gained from TKE and MIE and lost to MIE. The same non-negligible energy transfer through TKE, MKE and MIE is observed for both the conditions. 相似文献