先进的具高出力的核电汽轮机

介绍了西门子设计制造先进大功率核电汽轮机的长期运行经验,并发展半速饱和蒸汽核电汽轮机,功率达1700MW,末级长叶片高度为1829mm,从设计、工艺、材料选择等方面论述了提高机组出力、提高机组效率、减少腐蚀的方法,其中包括套装叶轮设计、3DSTM叶片技术、高压透平和低压透平等。     

Ehlers-Danlos syndrome type II in pregnancy

The Allen test was performed by four physician examiners on 200 hands of healthy volunteers. Positive results were found in 5.5% of hands. There was not a single case in which all four observers agreed. Considerable inter-observer disagreement is associated with the Allen test.     

Reaktionen beim Aufblasen von Kohlendioxid auf Fe-C-Cr-Schmelzen unter Vakuum

Abbrandverhalten der Begleitelemente. Entkohlungsgeschwindigkeit. Frischmittelausnutzung. Eindringtiefe eines Luftstrahls in Wasser. Chromverschlackung.     

Three write heads are as good ask

Nondeterministic one-wayk-head writing finite automata are investigated. It is shown that 3-head automata with one read-write head followed by two read-only heads are as powerful as any multihead automaton. Furthermore, a new way to detect a coincidence of heads is introduced, which has as a consequence that it makes no difference, whether the heads make stationary moves ore-moves.This research was done while the author visited the Department of Mathematics, University of California at Santa Barbara.The work was supported in part by the National Science Foundation under Grant MCS 77-11360 and by the German Academic Exchange Service under NATO Research Grant 430/402/777/9.     

Endogenous oestrogen state in women with postmenopausal bleeding (author's transl)

The endogenous oestrogen state in 52 women (33 with endometrial carcinoma and 19 with benign conditions of the endometrium) was assessed ny means of histological examinations of vaginal swabs and of radio-immunological determinations of 17 beta-oestradiol. Considering their age, these women displayed an oestrogen activity far exceeding that found in previous studies. There was no difference between the oestrogen levels in women with carcinoma and the other patients. Furthermore, it was stiking that in the same group of women the examined parameters frequently showed different results. Consequently, a diagnosis based solely on the investigation of one parameter must frequently be misleading.     

The Metrology Light Source of PTB – a Source for THz Radiation

The Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute, operates the low-energy electron storage ring Metrology Light Source (MLS) in Berlin-Adlershof in close cooperation with the Helmholtz-Zentrum Berlin (HZB). The MLS is designed and prepared for a low-α machine optics mode based on a sextupole and octupole correction scheme, for the production of coherent synchrotron radiation in the far-IR and THz region. In our contribution we present commissioning results, which clearly indicate that the MLS, in combination with dedicated beamlines, offers intense, stable, and well-focused THz radiation. We discuss the planned use of the MLS for metrology in the THz spectral range.     

Nanoimprint lithography for high-efficiency thin-film silicon solar cells

We demonstrate high-efficiency thin-film silicon solar cells with transparent nanotextured front electrodes fabricated via ultraviolet nanoimprint lithography on glass substrates. By replicating the morphology of state-of-the-art nanotextured zinc oxide front electrodes known for their exceptional light trapping properties, conversion efficiencies of up to 12.0% are achieved for micromorph tandem junction cells. Excellent light incoupling results in a remarkable summed short-circuit current density of 25.9 mA/cm(2) for amorphous top cell and microcrystalline bottom cell thicknesses of only 250 and 1100 nm, respectively. As efforts to maximize light harvesting continue, our study validates nanoimprinting as a versatile tool to investigate nanophotonic effects of a large variety of nanostructures directly on device performance.     

Grid indentation analysis of composite microstructure and mechanics: Principles and validation

Several composites comprise material phases that cannot be recapitulated ex situ, including calcium silicate hydrates in cementitous materials, hydroxyapatite in bone, and clay agglomerates in geomaterials. This requirement for in situ synthesis and characterization of chemically complex phases obviates conventional mechanical testing of large specimens representative of these material components. Current advances in experimental micro and nanomechanics have afforded new opportunities to explore and understand the effect of thermochemical environments on the microstructural and mechanical characteristics of naturally occurring material composites. Here, we propose a straightforward application of instrumented indentation to extract the in situ elastic properties of individual components and to image the connectivity among these phases in composites. This approach relies on a large array of nano to microscale contact experiments and the statistical analysis of the resulting data. Provided that the maximum indentation depth is chosen carefully, this method has the potential of extracting elastic properties of the indented phase which are minimally affected by the surrounding medium. An estimate of the limiting indentation depth is provided by asssuming a layered, thin film geometry. The proposed methodology is tested on a “model” composite material, a titanium-titanium monoboride (Ti–TiB) of various volumetric proportions. The elastic properties, volume fractions, and morphological arrangement of the two phases are recovered. These results demonstrate the information required for any micromechanical model that would predict composition-based mechanical performance of a given composite material.