Zu einem Phänomen der Lochkorrosionsbegrenzung bei hochlegierten Sonderedelstählen und NiCrMo-Legierungen in Chloridlösungen

On a phenomenon of the limitation of pitting corrosion at high alloyed special stainless steels and NiCrMo-alloys in chloride solutions Testing the pitting corrosion resistance of high alloyed special stainless steels and NiCrMo-alloys in chloride solutions there was observed a limitation of the pitting corrosion range toward more positive potentials. Above this limitation, the so-called pitting corrosion limitation potential, the pit initiation by all means is prevented, but the growth of pits which had been initiated before in the pitting corrosion range not necessarily comes to a stop. Therefore current density-potential curves which are obtained by downward polarization after an initial potential jump into the transpassive region and chronopotentiostatic tests are more suitable to investigate this phenomenon than cyclic polarization measurements and potentiostatic alteration tests. There is indicated a dependence of this phenomenon on temperature. The phenomenon of a limitation of the pitting corrosion range toward more positive potentials has been found until now at alloy 926, alloy 31, alloy 28, alloy 59 and alloy C-276.     

方便显示器升级的复合型VGA编码器／解码器

较老式的计算机系统通过4根75Ω同轴电缆把RGB(三原色)视频和复合同步信号输送到150英尺外的RGB彩色监视器。如需升级,用于替换的VGA视频卡可直接驱动VGA监视器的内部端接部件带来的75Ω负载。但是,VGA标准使用单独的水平和垂直正向同步信号。向原始电缆添加一根额外的同轴电缆来承载单独的同步信号,这是一种困难并且成本很高的建议。一个明显的解决方案就是把单独的同步信号组合到一种复合格式中。图1中的组合器电路很简单,成本很低,并且可用随时供货的备件来迅速组装。     

Uncertainty in Quantitative Electron Probe Microanalysis

Quantitative electron probe analysis is based on models based on the physics or x-ray generation, empirically adjusted to the analyses of specimens of known composition. Their accuracy can be estimated by applying them to a set of specimens of presumably well-known composition.     

The microscopy cell (MicCell), a versatile modular flowthrough system for cell biology, biomaterial research, and nanotechnology

We describe a novel microfluidic perfusion system for high-resolution microscopes. Its modular design allows pre-coating of the coverslip surface with reagents, biomolecules, or cells. A poly(dimethylsiloxane) (PDMS) layer is cast in a special molding station, using masters made by photolithography and dry etching of silicon or by photoresist patterning on glass or silicon. This channel system can be reused while the coverslip is exchanged between experiments. As normal fluidic connectors are used, the link to external, computer-programmable syringe pumps is standardized and various fluidic channel networks can be used in the same setup. The system can house hydrogel microvalves and microelectrodes close to the imaging area to control the influx of reaction partners. We present a range of applications, including single-molecule analysis by fluorescence correlation spectroscopy (FCS), manipulation of single molecules for nanostructuring by hydrodynamic flow fields or the action of motor proteins, generation of concentration gradients, trapping and stretching of live cells using optical fibers precisely mounted in the PDMS layer, and the integration of microelectrodes for actuation and sensing.     

Analyse flüchtiger Inhaltsstoffe des Holunders

European Food Research and Technology - Die Analyse und Identifizierung von Aromastoffen mittels GC/MS-Technik aus Holunderbeeren und -blüten wird beschrieben. Durch Extraktion mit...     

Analysis of the Survivability of GaN Low-Noise Amplifiers

This paper presents a detailed analysis of the stressing mechanisms for highly rugged low-noise GaN monolithic-microwave integrated-circuit amplifiers operated at extremely high input powers. As an example, a low-noise amplifier (LNA) operating in the 3-7-GHz frequency band is used. A noise figure (NF) below 2.3 dB is measured from 3.5 to 7 GHz with NF<1.8 dB between 5-7 GHz. This device survived 33 dBm of available RF input power for 16 h without any change in low-noise performance. The stress mechanisms at high input powers are identified by systematic measurements of an LNA and a single high electron-mobility transistor in the frequency and time domains. It is shown that the gate dc current, which occurs due to self-biasing, is the most critical factor regarding survivability. A series resistance in the gate dc feed can reduce this gate current by feedback, and may be used to improve LNA ruggedness     

Synthesis of Aminopyridazines from Aminocyclopropenylium Salts and Diazomethyl Compounds [1]

Amino-substituted cyclopropenylium salts ( 11a,b ) react with diazomethyl compounds ( 12a-i ) in dichloromethane or acetonitrile in the presence of a base (ethyldiisopropylamine, 1,5-diazabicyclo[4.3.0] non-5-ene) to form 4-aminopyridazines ( 13a-i ) specifically. The reaction is interpreted in terms of an initial electrophilic diazoalkane substitution to give diazomethylcyclopropenes ( 11 + 12 → 14 ) which undergo a [1.5]-cyclisation to form the betaines 16 which, in turn, isomerise with opening of the bridging bond to give the aminopyridazines 13 . In a similar manner, the tris[amino] cyclopropenylium salts 8a,b and 10a-c are converted to the 3,4,5-tris[amino]-pyridazines ( 21a-k ) by treatment with diazomethyl compounds ( 12a, c-f ).     

Trypsin inhibitor activity of soybean as affected by genotype and fertilisation

The presence of protease inhibitors in soybean prohibits the utilisation of the raw beans for food and feed. However, little information is available about environmental influences and the effects of nitrogen and sulphur supply on the antinutritional constituents of soybean. As these factors may influence protease inhibitors, soybean genotypes segregated according to the presence or absence of the Kunitz trypsin inhibitor have been evaluated for trypsin inhibitor activity (TIA) in field trials. TIA was affected significantly by environment (geographical location), fertilisation treatment and genotype. Environmental means of TIA were between 69.5 and 104.8 mg g^?1. Nitrogen application, which caused an increase in seed protein content, resulted in a reduction in TIA by about 15% as compared with the control. Remarkably, simultaneous application of nitrogen and sulphur in the form of ammonium sulphate had a similar reductive effect on TIA to that of nitrogen application alone, although soybean protease inhibitors are rich in sulphur amino acids. Significant genetic variation in TIA was found both within the genotype class with the Kunitz inhibitor present as well as within the class lacking this inhibitor. The results suggest that TIA of soybean may be modified considerably by genetic improvement and appropriate agronomic management. Copyright © 2003 Society of Chemical Industry