共查询到20条相似文献,搜索用时 31 毫秒
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借助统计学软件S P S S, 介绍对物理试卷质量定量分析的方法. 包括对样本资料绘制成绩分布曲线, 进
行难度、 区分度、 信度及效度, 即分析试卷质量常用的“ 四度”指标的定量计算与分析, 提高广大教师分析试卷的效
率, 准确得到分析结果, 为今后的教学和考试提供科学依据 相似文献
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报道在镁金属蒸气中利用两束激光三光子共振激发原子3snp1P中高里德堡态时,观察到随泵浦激光功率的增强,出现3s4s1S0-3sns1S0、3snd1D2(n≈18~32)偶宇称态偶极禁戒跃迁增强,以及3sns1S0能级移动现象,并解释为光泵过程引起的原子激发态碰撞效应。利用禁戒跃迁首次测定了Mg3sns1S0(n=22~30)能级。 相似文献
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联吡啶以分子水平掺入SiO2凝胶玻璃中,显示出独特的光谱性质。其发射光谱除了正常的S1→S0跃迁产生的中心位于400nm的发射峰外,还出现了中心位于454nm的激基缔合物发射峰。经200℃处理后,联吡啶分子受Si-O网络刚性约束,激基缔合发射峰消失,出现了基于S2→S0辐射跃迁产生的325nm高能级发射峰。至550℃处理后,因联吡啶分子基本进入Si-O三维网络的间隙,发射光谱中只剩下振动结构明显的高能级荧光峰。上述结果为表征有机/无机复合材料微结构演变提供了荧光探针工具。 相似文献
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主要用AM1半经验分子轨道方法对S10、S11和S12的 几何结构进行了计算,并比较了不同构型的稳定性。 相似文献
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Inclusive γ(1S,2S,3S) photoproduction at the future Circular-Electron-Positron-Collider(CEPC)is studied,using the non-relativistic quantum chromodynamics(NRQCD)factorization formalism.Including the contributions from both direct and resolved photons,we present different distributions for the γ(1S,2S,3S) production.Our results suggest that there will be considerable events,implying that well measurements of the T photoproduction can be performed to further study heavy quarkonium physics at electron-positron colliders,in addition to hadron colliders.This supplemental study is very important for clarifying the current situation regarding the heavy quarkonium production mechanism. 相似文献
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V. V. Vladimirsky V. K. Grigor’ev I. A. Erofeev O. N. Erofeeva Yu. V. Katinov V. I. Lisin V. N. Luzin V. N. Nozdrachev V. V. Sokolovsky G. D. Tikhomirov Yu. P. Shkurenko 《Physics of Atomic Nuclei》2006,69(3):493-509
On the basis of experimental data from the 6-m spectrometer of the Institute of Theoretical and Experimental Physics (ITEP, Moscow), an amplitude analysis of 40 553 events of the reaction π ? p → K S K S n induced by a negatively charged pion of energy 40 GeV is performed over a broad momentumtransfer range by using a new procedure. The results for |t| > 0.1 GeV2 are obtained for the first time. In particular, resonances of mass 1700 and 1900 MeV and width 120 MeV are discovered in the D + wave (there were no such resonances for |t| < 0.1 GeV2). In the region of low momentum transfers, the S wave exhibits a structure that lies in the mass region around 1370 MeV and which requires three resonances for its explanation. Two of these (that of mass 1234 ± 6 MeV and width 47 ± 33 MeV and that of mass 1478 ± 6 MeV and width 119 ± 10 MeV) were found in the studies of A. Etkin et al. [Phys. Rev. D 25, 2446 (1982)] and O.N. Baloshin et al. {Yad. Fiz. 43, 1487 (1986) [Phys. At. Nucl. 43, 959 (1986)]}. The third has a mass of 1389 ± 9 MeV and a width of 30 ± 24 MeV. At high momentum transfers, the S wave is found to feature resonances that have the following parameters: M = 1328 ± 8 MeV and Γ = 237 ± 20 MeV, M = 1440 ± 6 MeV and Γ = 121 ± 15 MeV, and M = 1776 ± 15 MeV and Γ = 250 ± 30 MeV. For the D 0 wave, it is found that, in addition to the well-known resonances f 2, a 2, and f′ 2, there appear the following resonances in this wave: a resonance of mass 2005 ± 12 MeV and width 209 ± 32 MeV and a resonance of mass 2270 ± 12 MeV and width 90 ± 29 MeV at low |t| and a resonance of mass 1659 ± 6 and width 152 ± 18 and a resonance of mass 2200 ± 13 MeV and width 91 ± 62 MeV at high |t|. 相似文献
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缄默知识在实际教学中扮演着重要角色. 对于我国现行的渗透式物理S T S教学, 其情境性和实践性的
特点使得教学中的缄默知识更容易与学生头脑中的缄默知识产生共鸣, 这对于教学的有效展开和学生的科学素养
的锻炼都有积极作用. 本文旨在通过探究基于缄默知识理论的物理S T S教学模式, 对于现今S T S教学提出一些建
议和看法 相似文献
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Abstract Two new sulphur are reported in monocristalline rubidiumchloride doped with rubidium and sulphur, and irradiated with X-rays at room temperature. By an extensive comparison with other experimental data on chalcogen centres in alkali halides an interstitial RbCl:S? and a substitutional RbCl:S? 3 model is proposed for these paramagnetic defects. Theoretical calculations confirm the S? ion model for the former. 相似文献
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根据能量方法原理,通过单位力法和卡氏定理分析方法,理论计算得出了给定位移变形条件下沿S弯的弯矩、应力分布.分析表明,沿S弯结构的应力主要由热收缩变形产生,但重力影响也不可忽略,考虑重力影响后沿S弯最大应力较不考虑重力时增大了10%.根据该理论原理编程计算发现,在S弯高度受限的条件下,圆弧段半径越小,结构最大应力越小,实际没计中可根据强度要求结合加工工艺选择合适的圆弧半径.该分析方法为有效优化结构设计提供了理论指导. 相似文献
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联吡啶以分子水平掺入SiO2凝胶玻璃中, 显示出独特的光谱性质. 其发射光谱除了正常的S1→S0跃迁产生的中心位于400 nm的发射峰外, 还出现了中心位于454 nm的激基缔合物发射峰. 经200 ℃处理后, 联吡啶分子受Si-O网络刚性约束, 激基缔合发射峰消失, 出现了基于S2→S0辐射跃迁产生的325 nm高能级发射峰. 至550 ℃处理后, 因联吡啶分子基本进入Si-O三维网络的间隙, 发射光谱中只剩下振动结构明显的高能级荧光峰. 上述结果为表征有机/无机复合材料微结构演变提供了荧光探针工具. 相似文献
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Qibin Li 《Molecular physics》2014,112(7):947-955
The mechanism of sulphur nucleation in S–H2S system is investigated by molecular dynamics simulation with the ReaxFF reactive force field. The results indicate that the nucleation of sulphur requires certain conditions. The nucleus of sulphur will form once the allotropes of sulphur dissolve from polysulphanes. Separate sulphur atoms aggregate into the cluster in the initial stage of nucleation according to the snowball effect. The cluster of nucleation is judged by the average distance of the neighbour sulphur atoms, which is identified as 2.8 Å through a parametric study. The sustainable process of nucleation depends on whether the cluster can overcome its critical state. The formation of the cluster may accelerate its own nucleation/coalescence and H2S decomposition. 相似文献
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S参数是网络分析仪的基本测量参数,它包括了反射系数(驻波系数)、传输系数(或衰减系数)、相位等参数。通过引进射频矢量网络分析仪,可完善和建立本单位射频S参数测试标准,实现S参数量值统一,开展仪器设备和元部件的射频S参数现场及实验室检定。 相似文献
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1 IntroductionThestudyofsulphurbybeam-foilspectroscopyisinterestingfortworeasons.First,thehighcosmicabundanceofsulphurelement,n?.. 相似文献
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O. Arnoult F. Nez L. Julien F. Biraben 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(2):243-256
This article reports the first optical frequency measurement of the 1S–3S transition in hydrogen. The excitation of this transition
occurs at a wavelength of 205 nm which is obtained with two frequency doubling stages of a titanium sapphire laser at 820 nm.
Its frequency is measured with an optical frequency comb. The second-order Doppler effect is evaluated from the observation
of the motional Stark effect due to a transverse magnetic field perpendicular to the atomic beam. The measured value of the
1S1/21\mathrm{S}_{1/2}(F = 1)-3S1/2(F = 1) frequency splitting is 2 922 742 936.729(13) MHz with a relative uncertainty of 4.5 × 10-12. After the measurement of the 1S–2S frequency, this result is the most precise of the optical frequencies in hydrogen. 相似文献
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Pressure-Induced Metallization Accompanied by Elongated S–S Dimer in Charge Transfer Insulator NiS_2 下载免费PDF全文
The insulator-metal transition triggered by pressure in charge transfer insulator NiS2 is investigated by combining high-pressure electrical transport,synchrotron x-ray diffraction and Raman spectroscopy measurements up to40-50 GPa.Upon compression,we show that the metallization firstly appears in the low temperature region at~3.2 GPa and then extends to room temperature at~8.0 GPa.During the insulator-metal transition,the bond length of S-S dimer extracted from the synchrotron x-ray diffraction increases with pressure,which is supported by the observation of abnormal red-shift of the Raman modes between 3.2 and 7.1 GPa.Considering the decreasing bonding-antibonding splitting due to the expansion of S-S dimer,the charge gap between the S-ppπ* band and the upper Hubbard band of Ni-3 d eg state is remarkabl.y decreased.These results consistently indicate that the elongated S-S dimer plays a predominant role in the insulator-metal transition under high pressure,even though the p-d hybridization is enhanced simultaneously,in accordance with a scenario of charge-gap-controlled type. 相似文献