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991.
激光诱导击穿光谱实验装置的参数优化研究 总被引:1,自引:0,他引:1
Zhang L Ma WG Yan XJ Li ZX Hu ZY Zhang YZ Wang L Dong L Yin WB Jia ST 《光谱学与光谱分析》2011,31(9):2355-2360
为了使激光诱导击穿光谱(LIBS)实验装置中的多个关键参数达到最优化设置,以便更好地服务于煤质分析,实验中对这些参数与煤粉等离子体中待测元素发射谱线信噪比间的关系进行了详细研究,并根据信噪比大小来进行最优化参数的选择.实验结果表明,对于本LIBS实验装置,其最优化参数设置是将激光脉冲能量设为120 mJ·Pulse-1... 相似文献
992.
993.
本文旨在探讨条件非线性最优扰动(CNOP)方法在陆面过程模式的参数优化工作方面的扩展应用.使用通用陆面模式(CoLM)和CEOP地面基准站——吉林通榆站退化草地2006年生长季的资料,针对土壤颜色、砂土比例和叶面积指数等关键模式参数,使用感热通量、潜热通量和浅层土壤温湿度作为检测变量,设计了单参数和多参数优化试验.结果表明,CONP扩展方法得到的优化参数提高了CoLM对检测变量的模拟能力,并且多参数的优化结果明显优于单参数的优化结果,在模式模拟偏差较大的土壤湿度方面改进尤为显著,此外,使用了差异进化算法(
关键词:
条件非线性最优扰动(CNOP)
陆面过程模式
参数优化 相似文献
994.
A. MansooriB. Roshanzadeh M. KhalajiS.H. Tavassoli 《Optics and Lasers in Engineering》2011,49(3):318-323
Determination of elemental composition of cement powder plays an important role in the cement and construction industries. In the present paper, Laser induced breakdown spectroscopy (LIBS) is used for measuring the concentration of cement ingredient. Cement powder samples are pressed into pellets. Laser pulses are focused on the surface of pellets. A microplasma is formed in the front of samples. The plasma emission contains information about the elemental composition of the samples. By assumption of local thermodynamic equilibrium (LTE) and using several standard cement samples, a calibration curve is prepared for each element. The major and minor elements of cement such as Ca, Si, K, Mg, Al, Na, Ti, Mn and Sr are qualitatively and quantitatively determined. For verification of LTE conditions, plasma parameters such as plasma electron temperature and electron density are computed. According to the obtained results, the LIBS technique could be a suitable method for determination of elemental composition in the cement production industries. 相似文献
995.
Possible structures and properties of some excited states of Λc+ dynamically generated in the coupled-channel P-wave meson-baryon scattering are studied by solving the Bethe-Salpeter(BS) equation in the framework of the Chiral Unitary Approach. It is shown that both Λc+(2765) and Λc+(2940) could be generated dynamically and could be compound states with multi-configuration molecular-like structures. The couplings of the generated states to various reaction channels are also calculated. Moreover, two highly excited states, Λc+(3024) and Λc+(3134), are predicted. 相似文献
996.
The channel-dependent Argonne Av18 effective two-body interactions (CDEI) which are generated through the lowest order constrained variational (LOCV) calculation for asymmetric nuclear matter with the charge-dependent Av18 bare nucleon–nucleon potential are used to calculate the ground state properties of heavy closed shell nuclei such as 48Ca, 90Zr, 120Sn and 208Pb. The harmonic oscillator basis, and the local density approximation (LDA) are applied to create the relative and the center of mass dependent effective two-body potential. We get more binding with respect to the similar calculation with the Reid types potentials. It is tried to omit the LDA and perform full calculation with the Av18CDEI for light nuclei. The results indicate that the LDA works quite well. It is also shown that in case of heavy closed shell nuclei and unlike our previous report with Reid68Day interaction, the contributions of higher partial waves (J>2) are very important for the calculations with Av18 potential and we get reasonable agreement between our calculated binding energies and RMS radii, with those predicated by the others methods, and the experimental data. Finally, the various aspects of channel and density dependent two-body effective interactions are discussed. 相似文献
997.
C. Degrande J.-M. GérardC. Grojean F. MaltoniG. Servant 《Physics letters. [Part B]》2011,703(3):306-309
We study the phenomenology of same sign top pair production at the LHC in a model-independent way. The complete set of dimension six operators involving two top (or anti-top) quarks is introduced and the connection with all possible t- or s-channel heavy particle exchanges is established. Only in the former case, same and opposite sign top pair production can be related. We find that while current Tevatron data disfavor t-channel models, other production mechanisms are viable and can be tested at the LHC. 相似文献
998.
Hideo Hasegawa 《Physica A》2011,390(8):1486-1503
The thermal entanglement of the Hubbard dimer (two-site Hubbard model) has been studied with the nonextensive statistics. We have calculated the auto-correlation (Oq), pair correlation (Lq), concurrence (Γq) and conditional entropy (Rq) as functions of entropic index q and the temperature T. The thermal entanglement is shown to considerably depend on the entropic index. For q<1.0, the threshold temperature where Γq vanishes or Rq changes its sign is more increased and the entanglement may survive at higher temperatures than for q=1.0. Relations among Lq, Γq and Rq are investigated. The physical meaning of the entropic index q is discussed with the microcanonical and superstatistical approaches. The nonextensive statistics is applied also to Heisenberg dimers. 相似文献
999.
Real-world magnetic resonance imaging of the brain is affected by intensity nonuniformity (INU) phenomena which makes it difficult to fully automate the segmentation process. This difficult task is accomplished in this work by using a new method with two original features: (1) each brain tissue class is locally modeled using a local linear region representative, which allows us to account for the INU in an implicit way and to more accurately position the region's boundaries; and (2) the region models are embedded in the level set framework, so that the spatial coherence of the segmentation can be controlled in a natural way. Our new method has been tested on the ground-truthed Internet Brain Segmentation Repository (IBSR) database and gave promising results, with Tanimoto indexes ranging from 0.61 to 0.79 for the classification of the white matter and from 0.72 to 0.84 for the gray matter. To our knowledge, this is the first time a region-based level set model has been used to perform the segmentation of real-world MRI brain scans with convincing results. 相似文献
1000.