排序方式: 共有47条查询结果,搜索用时 31 毫秒
1.
A thorough investigation of the systemd~2y(x):dx~2 p(x)y(x)=0with periodic impulse coefficientsp(x)={1,0≤xx_0>0) -η, x_0≤x<2π(η>0)p(x)=p(x 2π),-∞相似文献
2.
在X射线荧光分析中,基本参数法是校正元素间吸收增强效应的数学方法之一。我们使用带有不锈钢窗的~(241)Am59.6keVγ射线作为激发源,用Si(Li)半导体探测器和多道脉冲幅度分析器作为实验手段。采用无标样法,即绝对测量法,因而具有更大的广泛性和实用性。实验中,我们除了考虑元素间的二次、三次荧光吸收增强作用外,对样品中元素 相似文献
3.
Crystal structure and magnetic properties of SmCo-based films deposited on hot Si (1 0 0) substrates
SmCo-based films were deposited on Si (1 0 0) substrates by the rf magnetron sputtering process. The growth conditions are improved for the films deposited on hot Si substrates without the annealing process. The dependence of crystal structure and intrinsic coercivity on substrate temperature is chiefly investigated. It is suggested that TbCu7 type structural films can be obtained with enhanced in-plane magnetic properties with proper substrate temperature. 相似文献
4.
在平面抛物线坐标系中求解二维氢原子的Stark效应 总被引:2,自引:1,他引:1
在平面抛物线坐标系中计算了二维氢原子的Stark效应,得到了计算任意能级的一阶、二阶和三阶修正的普遍公式。 相似文献
5.
An efficient and straightforward strategy for the synthesis of N-(2-haloinden-1-yl)arenesulfonamides from propargylic alcohols and sulfonamides is described. Allenesulfonamide is postulated to be the key intermediate for this tandem transformation. 相似文献
6.
A three-component reaction of indoles, sulfonyl azides and terminal alkynes afforded 3-functionalized indoles in a single step via copper-cascade catalysis. 相似文献
7.
Weiwei Ling Huaiwu Zhang Ying He Yang Wu Kai Yang Yuanxun Li Sheng Li 《Journal of magnetism and magnetic materials》2010,322(7):819-823
The Ni-Cu-Zn ferrites with different contents of Bi4Ti3O12 ceramics (1-8 wt%) as sintering additives were prepared by the usual ceramic technology and sintered at 900 °C to adapt to the low temperature co-fired ceramic (LTCC) technology. The magnetic and dielectric properties of the ferrite can be effectively improved with the effect of an appropriate amount of Bi4Ti3O12. For all samples, the ferrite sintered with 2 wt% Bi4Ti3O12 has relatively high density (98.8%) and permeability, while the ferrite with 8 wt% Bi4Ti3O12 has relatively good dielectric properties in a wide frequency range. The influences of Bi4Ti3O12 addition on microstructure, magnetic and dielectric properties of the ferrite have been discussed. 相似文献
8.
Zhang Yuanxun Li Deyi Zhuang Guisun Zhang Guilin Wang Zhixing Xia Jun 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(3):939-941
This paper deals with the osteoporosis model of New Zealand rabbits in order to study the function of inorganic elements for
women patients with osteoporosis. The thirty cases of iliac crest are collected and determined using neutron activation analysis
(NAA). The results show that the fluorine concentrations in the experimental group are higher than those in control group
and the magnesium concentrations are significantly lower (P<0.001), but the concentrations of K, Na, Ca, Ba, Mn, Sr show no
remarkable difference. Combined with the serum biochemical markers of bone formation and resorption, the physiological functions
of some metal elements in bone are also discussed. 相似文献
9.
Zhang Yuanxun Li Deyi Ma Jixiao Huang Qiren 《Journal of Radioanalytical and Nuclear Chemistry》1997,222(1-2):263-265
Bone mineral density (BMD) determination has been performed in 210 selected Shanghai residents of both sexes of age range 15–50 using Hologic QDR-2000 dual energy X-ray absorptiometry (DEXA). The results showed that in female groups the peak value of L1-L4 BMD was 1.023 g/cm2 at the age of 31–35, but in the male groups it was 0.971 g/cm2 aged 26–30 and the peak period lasted till the group aged 46–50. The similar conclusion has also obtained by further statistics. 相似文献
10.
抛物线坐标系中的二维氢原子及其Runge—Lenz矢量 总被引:1,自引:0,他引:1
证明了二维氢在抛物线坐标系中的本征函数也是二维Runge-Lenz矢量x分量的本征函数,从而找到了二维氢原子在平面坐标系中的本征函数和在平面抛物线坐标系中的本征函数之间的变换矩阵。 相似文献