An analytical approach to determine conventional S−N curves from accelerated-fatigue data

This paper describes an analytical method of obtaining conventional S?N curves from the accelerated-fatigue tests, namely the generalized Prot accelerated-fatigue-testing technique in which the stress amplitude increases linearly with respect to cycle. Miner's cumulative-damage theory was applied and an expression for the sum of a series of natural numbers raised to a certain nonintegral power was developed to achieve this. The agreement between analytical prediction and experimental verification is quite reasonable.     

Übererlaubter Positronenzerfall von K38m,Sc42 und Ti43

The maximum energies and the half-lives of three shortlived β⁺-activities nearA=40 have been measured with a scintillation detector. The maximum β⁺-energies of 5.00±0.07 MeV (K^38m), 5.32±0.10 MeV (Sc⁴²) and 5.81±0.15 MeV (Ti⁴³) are in agreement with the predictions of a semiempirical formula.     

Synthesis and characteristics of bis(2,4-dimethyl-8-quinolinolato)(triphenylsilanolato)aluminum (III): A potential hole-blocking material for the organic light-emitting diodes

A new five-coordinated bis(2,4-dimethyl-8-quinolinolato)(triphenylsilanolato)aluminum (III) (24MeSAlq) material, having bulky substituents, was prepared in one-step reaction and was characterized. The photoluminescent (PL) spectrum of 24MeSAlq shows the largest hypsochromic shift exhibiting the maximum wavelength at the peak of 461 nm among the blue-emitting q₂AlOR-type complexes (q = 8-quinolinolato ligand and OR = aryloxy or alkoxy ligand) reported. The deep blue device composed of ITO/2-TNATA (60 nm)/NPB (15 nm)/24MeSAlq (20 nm)/Alq₃ (45 nm)/LiF (1 nm)/Al (100 nm), which uses 24MeSAlq as a hole-blocking layer and applies a principle efficiently confining an exciton recombination zone into a hole transporting layer, shows the maximum electroluminescent (EL) at the peak of 446 nm originating from the NPB emissive layer. This is attributed to an excellent hole-blocking property due to the high HOMO (highest occupied molecular orbital) energy level (6.14 eV).     

Spin sublevel-selective and position-dependent isotope effects in T1(ππ*) → S0 intersystem crossing of polycyclic para-diazines

ODMR measurements are combined with phosphorescence quantum yield data to show that deuterium isotope effects on the nonradiative decay rates of quinoxaline and dibenzoquinoxaline are spin sublevel-selective as well as position-dependent.     

Vibronic coupling and polyatomic spectra

A theoretical account of the vibronic intensity borrowing in polyatomic spectra is described and applied to the 3200 Å n → π^* absorption of pyrazine and the 3700 Å π → π^* absorption of pyrene. It is shown that the asymmetry between absorption and emission, as well as the frequency of the inducing mode in the lowest excited singlet state, are correctly predicted for both of these systems.     

CO2 laser induced reactions of trichloroethylene

The pressure and laser-power dependence of the product distributions in the TEA CO₂ laser induced decomposition of trichloroethylene were studied. At moderate pressures molecular elimination of HCl to give CClCCl via intermolecular energy transfer was found to be the major reaction path. At low pressures a pure laser-induced CCl bond fission to give CHCCl was found to be the primary, reaction step.     

Das Verhalten von Oberfläche zu Oberflächendruck von Fettsäure-Einzelschicten auf Mehrfachkomponenten-Substraten

Ohne Zusammenfassung     

Gravitational radiation from a binary system

It is shown that the gravitational radiation energy flux from a quasiperiodic binary system is given by the quadrupole formula contribution plus a nonlinear contribution which has been neglected in the past. The latter is found to depend on both the intensity of the gravitational field and the history of the radiating system. For PSR 1913+16, the nonlinear contribution to the energy flux may be neglected relative to that of the quadrupole formula.     

THE EFFECT OF ALA AND RADIATION ON PORPHYRIN/HEME BIOSYNTHESIS IN ENDOTHELIAL CELLS

To study porphyrin biosynthesis in human microvascular endothelial cells, HMEC-1 cells, a transformed human microvascular endothelial cell line, were incubated with 5-aminolevulinic acid (ALA), the precursor of endogenous porphyrins, and porphyrin accumulation was measured spectro-fluorometrically. The HMEC-1 cells accumulated porphyrin in a concentration-related and a time-dependent fashion. Protoporphyrin was the predominant porphyrin accumulated in the cells. The effect of light on protoporphyrin accumulation was evaluated by exposing the ALA-loaded HMEC-1 cells to ultraviolet-A (UVA) and blue light, followed by another incubation with ALA for 2–24 h. Enhancement of protoporphyrin accumulation in irradiated HMEC-1 cells was observed 2–24 h after irradiation, which was associated with a decrease in ferrochelatase protein and activity. Porphyrin accumulation from ALA after irradiation was significantly decreased when catalase (750–3000 U/mL, 29.3–44.3% suppression) or superoxide dismutase (270 U/mL, 36.4% suppression) was present during irradiation. These data demonstrate that HMEC-1 cells were capable of porphyrin biosynthesis, and that exposure of protoporphyrin-containing HMEC-1 cells to UVA and blue light, which includes the Soret band spectrum, decreased the ferrochelatase activity and its protein. These changes were mediated, at least in part, by reactive oxygen species.