排序方式: 共有66条查询结果,搜索用时 15 毫秒
11.
本文报导应用激光扫描,在Φ5mm至由60mm的外径上,实现±0.02mm动态测量精度的研究结果。文中对研究原理及精度分析作出简明阐述。 相似文献
12.
13.
The title compound (4,4′-H2bipy)[CdBr4]·H2O 1 has been synthesized via hydrothermal reaction and characterized by X-ray diffraction. The crystal belongs to monoclinic,space group P21/c with a=8.260(3),b=23.926(7),c=9.774(2),β=106.777(9)o,C10H12Br4CdN2O,Mr=608.26,V=1849.4(9)3,Z=4,Dc=2.185 g/cm3,S=1.005,μ(MoKα) =9.814 mm–1,F(000)=1128,R=0.0646 and wR=0.0989. The crystal structure analysis of 1 reveals that the title compound features an isolated structure,based on discrete 4,4′-H2bipy moieties and lattice water molecules which are linked by hydrogen bonds together with tetra-hedral cadmium atoms terminally coordinated by four bromine atoms. 相似文献
14.
<正>1引言考虑如下阻尼板振动方程初边值问题■其中?=(0, a)×(0, b)?R2, T是时间总量,■μ(μ> 0)为阻尼系数,ρ为给定正常数, f (x, y, t)是已知函数,φ1(x, y)和φ2(x, y)是初值函数,ψ1(y, t),ψ2(y, t),ψ3(x, t),ψ4(x, t)和g1(y, t), g2(y, t), g3(x, t), g4(x, t)是边值函数. 相似文献
15.
立几教材中推导台体体积公式的方法不是唯一的 ,因为用体积的割法可求出三棱台的体积 ,因此任意台体体积即可获解 .题 1 已知棱台A′B′C′ ABC中 ,设S△A′B′C′=图 1 方法 1图S1 ,S△ABC =S2 ,高为h .试推导三棱台的体积公式 .解 [方法 1]如图 1,连结AC′ ,AB′ ,CB′ .V台 =VA A′B′C′ VB′ ABC VA B′C′C=13S1 h 13S2 h VA B′C′C.VA B′C′CVB′ ABC=VA B′C′CVA BB′C′=S△B′C′CS△BB′C=B′C′BC ,VA B′C′CVA A′… 相似文献
16.
Ca2-xSrxZn4Ti15O36∶Pr red long decay phosphor was synthesized by high temperature solid state reaction. Photoluminescence property and crystalline and unit cell parameters of the orthorhombic were investigated by fluorescence spectrophotometer and by powder X-ray diffraction, respectively. The emission intensity at 618 nm changes sharply when the concentration of
Sr2+ (x) is less than 0.1 and the emission intensity reaches the maximum when x is equal to 0.007. There is an obviously broad excitation band at 270 nm when x is equal to 0.003 and it disappears gradually when x is over 0.01. The unit cell a parameter of
Ca2-xSrxZn4Ti15O36∶Pr decreases while c parameter increases with the increases of the concentration of the doped
Sr2+. When x is over 0.1 the value of the unit cell parameters a and c become stable. TL peaks of
Ca2Zn4Ti15O36∶Pr, Ca1.993Sr0.007Zn4Ti15O36∶0.002Pr3+,
0.002Na+, are located at 62 ℃, 88 ℃, respectively, which indicates that there are deeper traps in
Ca1.993Sr0.007Zn4Ti15O36∶0.002Pr3+,
0.002Na+. 相似文献
17.
18.
红色长余辉发光材料Ca2Zn4Ti15O36∶Pr3+的合成和发光性质 总被引:4,自引:1,他引:4
分别采用高温固相法和溶胶-凝胶法合成了新型红色长余辉发光材料Ca2Zn4Ti15O36∶Pr. 高温固相法合成Ca2Zn4Ti15O36需要在1200 ℃灼烧96 h才能形成纯物相. 热重分析曲线和X射线衍射分析结果表明 溶胶-凝胶法制得的前驱体在700 ℃灼烧12 h开始形成Ca2Zn4Ti15O36物相; 在1000 ℃灼烧24 h得到Ca2Zn4Ti15O36纯物相; 最佳反应温度为1000 ℃, 激活剂Pr3+的最佳浓度为0.6mol%, 发光强度比高温固相法增强了510%. 相似文献
19.
研究了Cu+,Eu2+共激活的CaS的发光性质及激活剂浓度与荧光性质的关系.Cu+和Eu2+的发射光谱分别在430nm附近及630nm附近,它们是由Cu,Ca-Vs2+中心的离子发射和Eu2+的5d-4f跃迁发射产生的.实验结果表明,Cu+对Eu2+荧光发射有较强的敏化作用,Eu2+对Cu+发射峰值波长和强度也有显著影响;单掺Eu2+或Cu+的荧光粉是良好的农用薄膜红,蓝光转换剂,共掺Eu2+和Cu+的CaS荧光粉作光转换农膜添加剂可望人工模拟叶绿素的吸收光谱,使作物在植物最佳生长作用光谱环境中生长,促使作物早熟或提高作物产量 相似文献
20.
Polarographic catalytic wave of hydrogen——Parallel catalytic hydrogen wave of bovine serum albumin in the presence of oxidants 总被引:1,自引:0,他引:1
A polarographic catalytic hydrogen wave of bovine serum albumin (BSA) at about -1.80 V (vs. SCE) in NH4CI-NH3 · H2O buffer is further catalyzed by such oxidants as iodate, per-sulfate and hydrogen peroxide, producing a kinetic wave. Studies show that the kinetic wave is a parallel catalytic wave of hydrogen, which resulted from that hydrogen ion is electrochemically reduced and chemically regenerated through oxidation of its reduction product, atomic hydrogen, by oxidants mentioned above. It is a new type of poralographic catalytic wave of protein, which is suggested to be named as a parallel catalytic hydrogen wave. 相似文献