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971.
Ultrasonic absorption studies in the intermediate state of superconducting tin have revealed sharp resonance peaks. Measurements have been made under wide variations of ultrasonic pulse frequencies. The possibility of correlating this study with a model proposed by Claiborne and Einspruch for hard superconducting alloys has been explored.  相似文献   
972.
Heterotrinuclear transition-metal complexes are of interest for the study of long-range magnetic interactions and as model compounds for the investigation of biological electron transport chains. The systems under study here contain paramagnetic Fe111-containing terminal units and a bridging unit with M11=Zn, Cu, Ni, Co, Fe, Mn. The spectroscopic methods applied include Mössbauer, — EPR- and magnetic susceptibility investigations. The spin-Hamiltonian analysis of the measured results yields information about the intramolecular super-exchange interactions among the various magnetic transmition-metal sites. In view of the 7Å separation between the two terminal Fe111 sites, the Fe111...Fe111 exchange coupling of the order ?10cm?1 is large.  相似文献   
973.
The classical problem of testing the equality of the covariance matrices from k ? 2 p-dimensional normal populations is reexamined. The likelihood ratio (LR) statistic, also called Bartlett’s statistic, can be decomposed in two ways, corresponding to two distinct component-wise decompositions of the null hypothesis in terms of the covariance matrices or precision matrices, respectively. The factors of the LR statistic that appear in these two decompositions can be interpreted as conditional and unconditional LR statistics for the component-wise null hypotheses, and their mutual independence under the null hypothesis allows the determination of the overall significance level.  相似文献   
974.
975.
A new theory for incorporating short range order (SRO) in the cluster Bethe lattice method (CBLM) for disordered binary alloys is proposed. It is applied to determine the condition for the appearance of moments in the disordered phase of a narrow-band metal for general values of concentration and SRO parameter. The final result (i) yields all the known limiting conditions exactly and (ii) displays in a transparant form the SRO dependence, indicating the merit of the present approach.  相似文献   
976.
We demonstrate a highly birefringent photonic crystal fiber by utilizing the asymmetric core design. Based on spectral measurements of the polarization mode interfering, we estimate that the fiber has a beat length of about 0.33 mm at 1545 nm.  相似文献   
977.
A generalized EOQ model for deteriorating items is considered here in which the demand rate, deterioration rate, holding cost and ordering cost are all assumed to be continuous functions of time. Shortages are also allowed and are completely backlogged. The planning horizon is finite and the replenishment periods are assumed to be constant. The optimal replenishment policy and the decision rule which minimizes the total system cost are derived. A numerical example is given to illustrate the developed model. Sensitivity analysis is also presented for the given model.  相似文献   
978.
A novel iridoid glucoside, named globularidin, lacking the typical double bond between C(3) and C(4), has been isolated from the whole plant of Globularia alypum by the combination of open column- and high-performance liquid chromatography. The structure of this compound was established by chemical transformation and spectral data.  相似文献   
979.
Pink-brown crystalline alkali-metal trifluoromonosulphatomanganates(III), A2[MnF3(SO4)] (A = NH4, Li, Na or K), have been synthesised in high yields by reacting KMnO4 or MnO(OH) with 40% HF and A2SO4 or by the reaction of MnO(OH) with 40% HF and A2S2O8 (A = NH4 or K). The chemicallly estimated oxidation state of manganese occurs between 2.9 and 3.1, and the room temperature magnetic moments lie in the range 4.0–4.2 BM. (NH4)2[MnF3(SO4)] on being pyrolysed at 340°C yields MnSO4.  相似文献   
980.
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