Influence of electron beam deflection techniques used during the cladding process on the wear and corrosion behaviour of cobalt‐based protective coatings on austenitic stainless steel

The present work aims to improve the wear resistance of the austenitic stainless steel X6CrNiMoTi17‐12‐2. In view of the potential use of this alloy, however, corrosion resistance should be maintained where possible. An electron beam surface treatment (cladding) was performed, and the cobalt‐based alloy Stellite® 12 was used as the wear‐resistant material. The presented results show the effects of several electron beam oscillation figures during the cladding process with regard to layer bonding, microstructure formation and hardness. The surface hardness achieved was 576±18 HV 0.3, almost three times higher than that of the base material (203±3 HV 0.3). The scratch energy density – which represents the resistance to abrasive wear – could be increased by a factor of 1.5. Under abrasive‐adhesive stress loading conditions, the determined wear volume decreased by a factor of almost 5. Based on the corrosion investigations carried out, it was possible to prove that in comparison to the base material, the tendency towards pitting corrosion could be almost completely suppressed.     

Comprehensive concept planning of urban greening based on ecological principles: a case study in Beijing, China

Greenspace is an important part of complex urban ecosystems and provides significant ecosystem services. It benefits urban communities environmentally, esthetically, recreationally and economically. Beijing Province is in north of China, and has a total area of 16,807.8 km² and a population of about 13.8 million. This paper aims to develop a comprehensive conceptual framework for urban greening of Beijing Province based on landscape ecological principles. It attempts to answer how to establish an urban greening plan at the regional, city and neighborhood levels to achieve long-term sustainability. At the regional level, a big natural and semi-natural forest area in the northwest and an ecological buffer belt in the southeast are planned to protect the environmental quality of Beijing and provide habitats for wildlife. At the city level, a green network system of green wedges, parks and green corridors has been proposed. This green network helps to limit future urban expansion, improve urban environmental quality and serve as habitats and migration routes for wildlife. At the neighborhood level, green extensions and connections of riverside greenway, road greenway, parks and vertical greening permeate into the built-up areas. They provide open space close to residential areas and offer places for recreation. This three-level green system constitutes an integrated ecological network for urban sustainable development of Beijing. For future development of Beijing, urban parks, forestry, agriculture, water and infrastructure should be planned and designed in an integrated way. After this greenspace plan is legislated and completely realized, Beijing will develop an interconnected and integrated network of urban greenspaces. It has the prospect of achieving the aim of “Green Olympic City 2008” and the long-term goal of developing Beijing towards an “Eco-City”.     

Antioxidant properties of differently processed spinach products

The effect of variously processed spinach products (whole-leaf, minced and enzymatically liquefied spinach) on lipid oxidation was determined. In an autoxidative methyl linoleate (MeLo) system the inhibition of hydroperoxide formation, measured by HPLC after three days of oxidation, was in descending order: whole-leaf > liquefied > minced spinach. The inhibition of formation of thiobarbituric acid-reactive substances (TBARS) and hexanal by spinach was determined in cooked meatballs with added spinach after two days of storage at 4 degrees C. The formation of TBARS was inhibited by liquefied spinach at 200 g/kg meat; all other spinach products tested at 100 and 200 g/kg were pro-oxidative. The formation of hexanal was inhibited by both minced and liquefied spinach at 100 and 200 g/kg meat. The variously processed spinach products behaved differently when tested for their antioxidant activity (MeLo) or oxidative stability (meatballs). We conclude that the effect of spinach products on lipid oxidation is affected by processing.     

Modeling, simulation, and measurement of nonlinearities in superconducting transmission lines and resonators

A simple phenomenological model of a nonlinear microwave transmission line is suggested. The dissipation of a traveling wave in the line is derived as a function of the microwave power. The phenomenological parameter of nonlinearity is introduced and found from experimental data. Nonlinear phenomena in a half-wavelength resonator, based on a superconducting microstrip line, are studied. The response in the form of output fundamental frequency, third harmonic, and intermodulation signals is found. Simulations based on the model are in good agreement with experimental data. Some problems of YBCO film production technology are discussed in connection with the high-power handling.     

The finite difference method for S-parameter calculation ofarbitrary three-dimensional structures

Describes the application of the finite-difference method for the determination of scattering parameters of passive, arbitrary three-dimensional, lossy structures. Maxwell's equations are solved in the frequency domain by solution of a boundary value problem. The generalized S-parameters can be computed for any one port or two port structure, while dielectric and conductor losses are taken into account. Higher order mode coupling can be considered and different geometries are allowed at the input and output ports. Verification calculations are given and results are presented for typical structures     

Supportive Organizational Climate and Managerial Assessment of MBO Effectiveness

Questionnaire data from 111 managers in a large utility firm showed significant positive relationships between supportiveness of the organizational climate in managers' immediate work groups and their assessment of MBO effectiveness. Climate-MBO effectiveness relationships were moderated by managers' need for independence and the type of work performed, but unaffected by organization level.     

Operation of hybrid current limiter based on high-Tcsuperconducting thin film

A high-Tc superconducting (HTSC) thin film with an inductive shunt was investigated as the model of a hybrid current limiter based on the superconducting-normal state transition. In addition to features previously observed in operation of other current limiters, sharp peaks of rather high frequency were found to appear on the background of a basic low-frequency voltage signal. This is attributed to self-oscillations of temperature and current in the superconductor. The influence of the frequency and magnitude of the circuit current on the character of self-oscillations was experimentally investigated. Qualitative analysis of the conditions for appearance of the self-oscillations under dc and ac conditions was carried out     

Structure quality in deep X-ray lithography applying commercial polyimide-based masks

The structure quality of deep X-ray lithography components strongly depends on the quality of the applied X-ray mask. In this article we compare the results obtained with two different mask types. Sophisticated working masks generated by e-beam lithography, soft X-ray lithography and electroplating of gold absorbers on a titanium mask membrane have been fabricated at the Institute for Microstructure Technology, Research Center, Karlsruhe (FZK/IMT), Germany. Prototype masks generated by e-beam lithography, optical lithography and electroplating of gold absorbers on a polyimide mask membrane have been fabricated by Optnics Precision, Japan, with the aim to offer commercially available low cost masks. Both mask types were applied to pattern PMMA resist layers of 300–750 μm thickness at the 2.5 GeV electron storage ring ANKA, Germany, using comparable process parameters. FZK/IMT masks provide microstructures with significantly better structure quality. The layout area, however, is currently limited to 12 cm², and the Ti mask membrane tends to lead to a slight resist surface attack, such as rounding of the resist edges. Optnics masks provide microstructures with reduced structure quality due to sidewall striations (sidewall roughness up to 2 μm) and thermal distortions (of up to 3–5 μm) which limit the potential scope of applications. They could nevertheless potentially be applied as low quality, low cost X-ray masks. High resolution and high accuracy applications, however, require more sophisticated but also more expensive masks, like the Ti-masks from FZK/IMT.     

UML vs. classical vs. rhapsody statecharts: not all models are created equal

State machines, represented by statecharts or state machine diagrams, are an important formalism for behavioural modelling. According to the research literature, the most popular statechart formalisms appear to be Classical, UML, and that implemented by Rhapsody. These three formalisms seem to be very similar; however, there are several key syntactic and semantic differences. These differences are enough that a model written in one formalism could be ill-formed in another formalism. Worse, a model from one formalism might actually be well-formed in another, but be interpreted differently due to the semantic differences. This paper summarizes the results of an informal comparative study of these three formalisms with the help of several illustrative examples. We present a classification of the differences according to the nature of potential problems caused by each difference. In addition, for each difference we discuss how translation between formalisms can be achieved, if at all.