混合表面活性剂-铬天青S与铜显色反应研究及应用

在曲拉通X-100(TritonX-100)和乳化剂(OP)存在下,基于Cu2+-铬天青S(CAS)的显色反应,建立了分光光度法测定微量铜的新方法.通过Cu2+与CAS-Triton X-100-OP形成灵敏度较高的多元配合物,来测量铜含量.络合物的最大吸收波长为618nm,表观摩尔吸光系数为ε=6.62×105L·m...     

Pr0．45（Ca1-xSrx）0．55MnO3体系调带宽引起的磁相变及电输运性质转变

采用固相法制备了Pr0．45（Ca1-xSrx）0．55MnO3（x=0．0,0．2,0．4,0．6,0．8,1．0）多晶样品．通过测量样品的X射线衍射（XRD）谱、磁化强度-温度（M～T）曲线、电阻率-温度（ρ～T）曲线,研究了Sr^2＋替代Ca^2＋对Pr0．45Ca0．55MnO3体系磁性和电性的影响．实验发现：...     

从开普勒定律到万有引力定律

从椭圆轨道出发,推导出了万有引力定律.     

在大学物理中讲授纵波的一点尝试

采用小球弹簧链模型和相对形变,以便于理解纵波的基本性质.     

关于渐近非扩张映射的Cesàro意义下的修正Ishikawa迭代(英文)

设E是一致凸Banach空间,且具有一致Gteaux可微范数,C是E的一个非空闭凸子集,T是渐近非扩张映射.对于任意x∈C,本文引入Cesàro意义上的修正Ishikawa迭代:x0=x∈C,yn=γnun+δnxn+(1-γn-δ)n+11∑j=0nTjxn,xn+1=μnvn+αnγf(xn)+βnxn+[(1-μn-βn)I-αnA]n+11∑j=0nTjyn,n≥0在适当的条件下证明此迭代序列的强(弱)收敛性.     

Synthesis and mesomorphic properties of trifluorobenzoate liquid crystal

Four series of trifluorobenzoate liquid crystals have been synthesized. Their phase transition temperatures have been also measured by texture observation in a polarizing microscope and confirmed by DSC. The influence of the lateral fluoro-substitution and triple bond has been also discussed.     

液体速凝剂的制备及性能

通过对多种市售有碱和无碱液体速凝剂产品的性能分析,分析总结了行业上速凝剂产品存在的不足之处。自制了一种无碱和一种有碱速凝剂产品,研究了不同辅料对速凝剂体系的协同增效作用,研究了环境温度、湿度、用水量、水泥种类等测试条件对速凝剂凝结时间的影响,总结了速凝剂在应用过程的注意事项及调整产品适应性的方法。     

一个大气氧压下Y_（0．9）Ca_（0．1）Ba_2Cu_4O_8掺Ag_2O复

在一个大气压的流动氧气氛中，通过重复烧结，合成了具有良好超导特性的Ｙ０．９Ｃａ０．１Ｂａ２ＣＵ４Ｏ８＋１０％ＷｔＡｇ２Ｏ复合块材．采用ＸＲＤ和ＳＥＭ技术对样品的结构分析表明：固相ＡＳ。Ｏ的加入对Ｙ０．９Ｃａ０．１Ｂａ２Ｃｕ４Ｏ８的相结构形成具有与熔融银添加法完全类似的加速作用；发现了存在于样品内部的Ａｇ偏聚和异常结构分布；探讨了不同掺Ａｇ２Ｏ工艺对样品结构和性能的影响．     

NON-NEGATIVE SOLUTIONS FOR A CLASS OF NON-POSITONE PROBLEMS

1IntroduInthispaperwestudyill(.)(l}xlsl(.)ll(:()noTI-1)ega,t]v(3s(>1lltionsfort,h(i1,woilo]lit,boundaryvalueproblemsu\ry;l;(:i.t>(v,>\,:t),:j:=fti-i'...ifn(j)>l),A>0isdcollstanta,f,dj'e(!'l,.,ti,fi<,,f(())<0(l.:i)111.of)i(lfllsifs{.1.l:)-(.I.2)havel,ecnsi…     

BOUND POLARONS IN ASYMMETRIC QUANTUM WELLS IN AN ELECTRIC FIELD

We have proposed the Hamiltonian of a polaron bound to a donor impurity in semiconductor quantum wells (QWs) in the presence of an electric field. The couplings of an electron with the confined bulk like longitudinal optical (L₀) phonons, halfspace L₀ phonons and interface phonons are considered. In particular, the interaction of the impurity with the various phonon modes is also included. We have calculated the ionization energy of a bound polaron in Al_xl Ga_1-xl As/GaAs/Al_xr Ga_1-xr As asymmetric and symmetric QWs. Results are obtained as a function of the barrier height (or equivalently of Al concentration x),the well width, the electric field intensities and the position of impurity in the QWs. Our numerical calculations show clearly that the interaction between the impurity and the phonon field plays an important role in screening the Coulomb interaction. It is shown that for at hin well (＜12nm), the cumulative effects of the electronphonon coupling and the impurityphonon coupling can contribute appreciably to the donor ionization energy and polarizability.