共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
3.
Highly monodispersed colloidal silica spheres in sub-micrometra size with distribution standard deviation less than 5% were synthesized by a chemical method.Using the self-crystallization of the silica spheres,we successfully obtained the three-dimensional close-packed face-centred-cubic silica matrices and artificial opals.Then,a colloidal photonic crystal embedded with CdS quantum dots (QDs) was also chemically prepared by using artificial opals as a template.A reflection spectra study reveals that both artificial opals with and without CdS QDs possess (111) directional photonic bandgap features. 相似文献
4.
Nucleon-χcJ dissociation cross sections are calculated in a constitutent interexchange model in which quark-quark potential is derived from the Buchmueller-Tye quark-anti-quark potential.These new cross sections for dominant reaction channels depend on the centre-of-mass energy of the nucleon and the charmonium. 相似文献
5.
6.
7.
Dirac‘s method which itself is for constrained Boson fields and particle systems is followed and developed to treat Dirac fields in light-front coordinates. 相似文献
8.
用等效F—P方法研究微腔激光器DBR腔的特性 总被引:1,自引:1,他引:0
采用等效F-P腔方法对VCSEL中上、下两个DBR构成的微腔进行了研究,计算并讨论了不同周期数的DBR对微腔结构的反射率的影响。结果表明,激射波长两侧存在对称的反射率峰值。随着上下层DBR周期数的增加:峰值带逐渐变平、变宽;中心波长的凹隐逐渐变细、变窄;考虑吸收损耗,中心波长反向率逐渐增加。 相似文献
9.
10.
在单、双迭代(包含三重激发微扰校正)耦合簇CCSD(T)理论水平下,采用cc-pvtz/Na、aug-cc-pvqz/He并加{3s3p2d1f}集的键函数组成的大基组,计算了He-Na2体系819个构型的相互作用能.通过对96个参数的解析表示的拟合,得到了体系的三维势能面.结果表明在Na2处于基态时该势能面上存在2个势阱,分别对应于线型和T型构型,阱深分别为1.58 cm-1,1.77 cm-1.整个势能面呈现出弱的角度各向异性.讨论了Na-Na键长变化对相互作用能的影响. 相似文献
11.
HL-2A是在原德国ASDEX基础上改进的大型托卡马克装置,该装置带有上下两组偏滤器线圈。从目前的HL-2A的改进方案看,其几何尺寸、磁场位形和物理参数大体和ASDEX相似,只是环向磁场、等离子体电流及拉长比稍有不同。由于未来的HL-2A装置上带有偏滤器,而我们以前的位形计算大多在没有偏滤器位形的HL-1及HL-1M上进行的,所以开展有关HL-2A位形的物理研究及相关的数值计算和程序设计是很重要的工作。 相似文献
12.
13.
利用Au-Si面垒探测器是灵敏区前的死层作为靶物质,研究了Hn^+(n≤7,250keV/p-450keV/p)团簇的其中的能损,得到能损比Rn〉1,且随团簇大小n和平均每核子能量增加而增大。 相似文献
14.
15.
16.
首次构造了放热反应Sr+CH3I的LEPS势能面,并进行了准经典轨线计算。重点计算了该反应产物平动能、振动能、转动能分布和转动取向与碰撞能的关系。其他方面如在更广碰撞能范围内的反应截面以及产物振动分布也做了研究,以便与相应的实验结果相比较—反应截面、产物振动分布与实验吻合。计算结果表明,随着碰撞能的增加,产物转动取向逐渐增强;平动能、转动能、振动能均增加,但平动能占总可用资能的比例下降。 相似文献
17.
18.
Calculation of Cross Section of Radiative Halo—Neutron Capture by ^12C at Stellar Energy with the Asymptotic Normalization Coefficient Method 下载免费PDF全文
The cross section of the direct neutron capture reaction 12C(n,γ)^13C(1/2^ ) is calculated with the asymptotic normalization coefficient method.The result is in good agreement with a recent experiment at low energy,An enormous enhancement of cross section is found for this direct neutron capture in which a p-wave neutron is captured into an 2s1/2 orbit with neutron halo.The possible effect of the neutron halo structure presented in this reaction on the s-precess in astrophysics is discussed in general. 相似文献
19.
地球上真有一个叫"黑洞"的地方,在印度的加尔各答.那是一栋建筑内的一间石砌的囚室,英国殖民者用来关押犯人,通常可以关押3~4人.1757年围绕这栋建筑发生了一场可怕的战斗.武装的印度民众与英军进行了血战.战斗结束后,死伤惨重的胜利者愤怒地把146名战败者塞进了这间囚室,关押了10个小时.第二天早晨,只有23名俘虏从"黑洞"中活着出来[1,2]. 相似文献
20.
Stability of Crystal Growth Face and Dissolution Face in Crystallization from Solution under Microgravity 总被引:1,自引:0,他引:1
The stability of the shapes of crystal growth face and dissolution face in a two-dimensional mathematical model of crystal growth from solution under microgravity is studied.It is proved that the stable shapes of crystal growth face and dissolution face do exist,which are suitably shaped curves with their upper parts inclined backward properly.The stable shapes of crystal growth faces and dissolution faces are calculated for various values of parameters,Ra,Pr and Sc.It is shown that the stronger the convection relative to the diffusion in solution is,the more backward the upper parts of the stable crystal growth face and dissolution face are inclined.The orientation and the shape of dissolution face hardly affect the stable shape of crystal growth face and vice versa. 相似文献