Determination of 5-methoxypsoralen in suntan cosmetics

A method for the determination of 5-methoxypsoralene in suntan-cosmetics is described. After liquid chromatographic clean-up, the final extract is screened by twodimensional thin layer chromatography. For positive extracts 5-methoxypsoralene is analysed quantitatively by capillary gas chromatography, using 5-alpha-cholestane as an internal standard and flame ionization detection (FID). The results were confirmed by gas chromatography-mass spectrometry (GC-MS). The recoveries for suntan-cosmetics of emulsion type were 70% and for tanning oils 90%. Detection limits of the method were 0,1 to 0,5 mg/kg, depending on the sample type. By application of this method 5-methoxypsoralene was detected in 6 of the 21 cosmetic products at levels up to 28 mg/kg.     

Semiconductor laser amplifier as optical switching gate

The properties of a semiconductor laser amplifier as optical switching gate are investigated. Particular attention is paid to gain, contrast ratio, and switching time of the device. These properties are studied experimentally and theoretically with respect to the injection current, optical input power, and cavity resonances. The experimental arrangements and the theoretical method are described. As an example of the various applications of semiconductor laser amplifier gates, packet switching experiments with self-routing, employing cascaded switching gates, are reported. In a theoretical analysis the restrictions that the properties of semiconductor laser amplifier gates impose on a larger switching system consisting of many such gates are investigated     

Designing the MPC105 PCI bridge/memory controller

The MPC105 peripheral component interconnection bridge/memory controller provides a platform-specification-compliant bridge between Power PC microprocessors and the PCI bus. With it, designers can create systems using peripherals already designed for a variety of standard PC interfaces. This bridge chip also integrates a secondary cache controller and high-performance memory controller that supports DRAM or synchronous DRAM and ROM or flash ROM     

Radiation effects on insulators for superconducting fusion magnets

Fibre-reinforced plastics (FRPs) are candidate materials for the insulation of superconducting magnet coils in future fusion reactors. This paper reports on a test programme performed to assess the mechanical properties of these materials and to obtain information on the damage and fracture mechanisms. Different types of FRPs (epoxies and poly- and bismaleimides as resins; two- and three-dimensional E-, S- or T-glass fabrics as reinforcements) were irradiated at room temperature by 2 MeV electrons and ⁶⁰Co-gamma rays up to 1.8 × 10⁸ Gy and by different reactor spectra up to a neutron fluence of 1 × 10²³ m⁻² (E > 0.1 MeV) at room temperature, 80 K or 5 K. Mechanical tests in tension as well as in the intralaminar crack opening and shear mode were carried out on the irradiated samples at 77 K. After low temperature irradiation, half of the samples were subjected to a warm-up cycle to room temperature before testing at 77 K. Results on the influence of different radiation sources and annealing cycles on the mechanical properties of these materials will be discussed.     

实现短流程钢铁企业最佳业绩中人的因素

德国巴登钢铁公司（BSW）炼钢厂有2座80t电炉，2座钢包炉和2台5流连铸机，由于BSW的生产和管理人员具有高的素质，精心保养设备，保持高生产率，从而降低生产成本。去年BSW炼钢厂生产140多万t质量合格钢坯。全员劳动生产率超过2000t钢／人·年。     

Thermal lens and beam properties in multiple longitudinally diodelaser pumped Nd:YAG slab lasers

The focal length of the thermal lens and the beam quality factor (beam propagation factor) M² for a multiple longitudinally diode pumped slab laser is deduced for pump and output powers up to 16 and 4.5 W, respectively. Due to the geometry of the arrangement, a stronger thermal lens is observed in the plane with the larger pump spot radius as predicted by an analytical model for slab geometries. In addition, the second stable zone of an asymmetric resonator is found to be advantageous for improved beam properties at high output powers     

Untersuchung des einflusses molekularer parameter auf morphologie und eigenschaften von polyethylenen niedriger dichte

Based on the example of PE-LD grades and on model substances obtained by preparative fractionation (fractions in the molecular weight range M?_w = 1.2 ? 390·10⁴ g/mol), comprehensive investigations regarding the problems of structure/properties have been carried out. The correlations of M?_w with 15 physical and application technological perameters have been investigated taking into account the reaction mechanism during the manufacturing of PE-LD in the tubular and agitated autoclave reactor, resulting in the formation of so-called primary structure perameters M?_n, M?_w, molar mass distribution, short chain branching and long chain branching. For the interpretation of the results, among other factors, also the morphological conditions have been taken into consideration, which in connection with the molecular parameters reveal — for specific M?_w-ranges — strong changes and saturation ranges, resp., for the physical and application technological properties.     

Preparation and properties of high molecular weight poly(1-germa-) or poly(1-sila-cis-pent-3-enes)

High molecular weight poly(1,1-dimethyl-1-germa-cis-pent-3-ene), poly(1,1-diphenyl-1-germa-cis-pent-3-ene), poly(1,1-dimethyl-1-sila-cis-pent-3-ene), and poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene) have been prepared. The thermal stability of these polymers is found to increase with their molecular weight.