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A series of Eu²⁺- and Mn²⁺-coactivated CaAl2Si2O8 phosphors have been synthesized at 1400 °C under a reduced atmosphere and their luminescence properties have been investigated as a function of activator and coactivator concentrations. We have discovered that energy transfers from Eu²⁺ to Mn²⁺ by directly observing significant overlap of the excitation spectrum of Mn²⁺ and the emission spectrum of Eu²⁺ as well as the systematic relative decline and growth of emission bands of Eu²⁺ and Mn²⁺, respectively. The critical distance and average separation of Eu²⁺ and Mn²⁺ have also been calculated. By utilizing the principle of energy transfer, we have also demonstrated that with appropriate tuning of activator content CaAl2Si2O8:Eu²⁺,Mn²⁺ phosphors exhibit great potential to act as a phosphor for white-light ultraviolet light-emitting diodes (UVLEDs).

Rate coefficients of the reaction O(³P) + HCl in the temperature range 1093−3197 K were determined using a diaphragmless shock tube. O atoms in the ground electronic ³P states were generated either by photolysis of SO2 with a KrF excimer laser at 248 nm or by pyrolysis of N2O with the shock wave. Their concentrations were monitored via atomic resonance absorption excited by emission from a microwave-discharged mixture of O2 and He. Rate coefficients determined in this work show non-Arrhenius behavior, with values consistent with previously reported measurements for T < 1486 K; they fit well with the equation k1(T) = (9.27 ± 0.03) × 10^-24 T ^3.67±0.18 exp[−(1030 ± 160)/T] cm³ molecule^-1 s^-1; listed errors represent one standard deviation in fitting. Theoretical calculations at the CCSD(T)/6-311+G(d, p) level locate a bent ³A‘ ‘ (TS1) and a linear ³A‘ (TS3) transition state characterized previously. On the basis of the results computed by CCSD(T)/ 6-311+G(3df,2p)//CCSD(T)/6-311+G(d,p), the rate coefficients predicted with conventional transition-state theory, including Eckart-tunneling corrections and with variational transition-state theory including zero- and small-curvature tunneling corrections, all agree satisfactorily with experimental observations.

Rate coefficients of reactions (1) CH3S + NO2 and (2) C2H5S + NO2 were determined using laser photolysis and laser-induced fluorescence. CH3S and C2H5S radicals were generated on photolysis of CH3SSCH3 and C2H5SSC2H5, respectively, with a KrF excimer laser at 248 nm. Their concentrations were monitored via fluorescence excited by emission from a dye laser at 371.4 nm (for CH3S) or 410.3 nm (for C2H5S) pumped with a pulsed XeCl excimer laser at 308 nm. Our measurements show that k1 (297 K) = (1.01 ± 0.15) × 10^-10 cm³ molecule^-1 s^-1 is similar to a value reported by Balla et al. and approximately 50% greater than other previously reported values; listed errors represent 95% confidence limits. Reaction 1 has a negative activation energy:  k1 = (4.3 ± 1.3) × 10^-11 exp[(240 ± 100)/T] cm³ molecule^-1 s^-1 for T = 222−420 K. Reaction 2 has a rate coefficient similar to reaction 1 at room temperature:  k2 (296 K) = (1.05 ± 0.16) × 10^-10 cm³ molecule^-1 s^-1 but has a small positive activation energy with k2 = (2.4 ± 0.7) × 10^-10 exp[−(210 ± 80)/T] cm³ molecule^-1 s^-1 for T = 223−402 K. The temperature dependence of k2 is determined for the first time. Reactions of NO2 with HS, CH3S, and C2H5S are compared.

We used a monoclonal antibody to a high molecular weight glycoprotein of the milk fat globule membrane to study at the ultrastructural level the sites of accumulation of immunoreactive material in breast tumors. By light microscopy, the antigen was found only on the luminal membrane of normal resting or lactating breast cells. In tumors, antigen could be found in the cytoplasm. We used the avidin-biotin-peroxidase complex immunoperoxidase technique to localize the site of cytoplasmic accumulation of immunoreactive material in breast tumors. This technique showed that antigen is found on the membrane of cytoplasmic vesicles. Some of these vesicles were collapsed and gave rise to what appeared to be clumps of free cytoplasmic immunoreactive material. We have also documented that in some tumors the entire cytoplasmic membrane bears antigen, whereas in other tumors only areas of cytoplasmic membrane that form microscopic lumina express antigen.