System simulation and realization of a resonant inverter with afield-controlled thyristor

The design, simulation, and realization of a single-ended quasi-resonant inverter (SEQRI) for induction heating applications are described. A novel power device, the field-controller thyristor (FCT), is used as a switching device. Full understanding and a proper realization of the circuit is obtained by accurate simulation with a software tool combining circuit and two-dimensional device simulation. With the use of combined circuit/device simulation, the operation of the system is predicted accurately. Comparison with experimental data showed excellent agreement. It is verified that a 15 A/1700 V FCT is an appropriate switching device for a SEQRI fed from a 220 V mains and delivering an output power of 1 kW     

3D optimization of average torque of electrostatic micromotors

The paper presents a technique to optimize electrostatic micromotors. The finite element technique is combined with different types of optimization strategies, one of them, a version of the evolution strategy is discussed. It further involves an automated generation of 3D meshes where the dimensions and rotor positions of the motor models can be chosen arbitrarily. It also involves constructing equivalent circuit models for the electrostatic motors. Both, the automated 3D mesh generation and the construction of the equivalent circuit model are treated in detail in this paper. The possibilities of producing powerful tools in the field of optimization are described, but also some warnings and limitations concerning the automated optimization are mentioned.     

高效低成本的硅双极GSM双频PA模块

提出了在单个陶瓷基底上利用硅射频Ic双极芯片技术设计PA模块的方法和测试数据.得到的数据表明利用硅技术生产出的产品性能可与现有GaAs技术产品相媲美.     

Development of Silica Aerogel Cerenkov Detectors

Recently silica aerogel has been employed as a Cerenkov radiator. This solid material can be produced with a refractive index of 1.01-1.10, thus complementing the refractive indices easily obtained with gases and liquids. It is very well suited for identification of particles having momenta of about one or a few GeV/c. Examples of efficient detectors with active surfaces of about 0.1 m2 using light collection system constructed from mirrors and diffusing walls are given. With a refractive index of 1.03 and an aerogel thickness of 9 cm, signals of about 6 photoelectrons have been obtained for ? = 1 particles.     

Malignant tumor and atherosclerotic plaque diagnosis usinglaser-induced fluorescence

A review of tissue diagnostics using laser-induced fluorescence is given with illustrations chosen from work performed by the authors' group. Two major topics are considered: the demarcation of malignant tumors from normal surrounding tissue and the identification of atherosclerotic regions in arteries. Specific fluorescence from injected agents and tissue natural autofluorescence are discussed. Steady-state and time-resolved fluorescence can be utilized. Original data showing immunity to blood interference in artery monitoring are presented. Imaging techniques for diseased tissue real-time visualization are discussed and illustrated     

Energy security policies in EU-25—The expected cost of oil supply disruptions

A framework for analyzing the impact on the expected cost of oil disruption by energy policies in EU-25 is developed. The framework takes into account how energy policies affect the oil market, the expected oil price increase, and the disruption costs. OPEC's strategic behavior is modelled as a dominant firm, and the model includes price interdependence between different energy commodities to better estimate the cost of an oil disruption. It is found that substituting pellets for oil in households and using imported sugar cane ethanol are cost-efficient policies if greenhouse gas benefits are included. Domestically produced wheat ethanol is not found to be cost-efficient even if both the expected cost of oil disruption and greenhouse gas benefits are included, the same also holds for hybrid vehicles. The gross expected economic gain of the policies is found to be between 9 and 22 €/bbl oil replaced.     

Genetic effects on stillbirth and calving difficulty in Swedish Holsteins at first and second calving

In Swedish Holstein dairy cattle, genetic effects on stillbirth and calving difficulty were studied in 411,409 first- and 281,193 second-calvers. A linear single-trait sire-maternal grandsire model and a threshold model using a Gibbs sampling technique were used to analyse calving data from 1985 to 1996. In first calving when using the linear model, the heritability of stillbirth on the visible scale was 4% for the direct effect and 3% for the maternal effect. For calving difficulty it was 6% and 5% for direct and maternal effects, respectively. In second calving the corresponding heritabilities for the two traits were considerably lower, less than 1%. Adjusting for calving difficulty in linear analysis of stillbirth halved the heritabilities for the direct and maternal effects in first calving. When using a threshold model, heritabilities for stillbirth in first-calvers were 12% and 8% for direct and maternal effects, respectively, and for calving difficulty they were 17% and 12%. At second calving corresponding heritabilities were 2 to 4% for stillbirth and 4 to 7% for calving difficulty. The correlation between direct and maternal effects was around -0.1, irrespective of whether the linear or the threshold model was used for first-calvers. The genetic correlations between bulls' EBV from first and second calving were 0.4 to 0.5 for direct and maternal effects in stillbirth, whereas they were 0.6 to 0.7 for calving difficulty. In first-calvers there was a substantial genetic variation in both traits, expressed by differences between breeding values of bulls, despite fairly low heritability. The results obtained in this study suggest that first-parity records should preferably be used for genetic evaluation of bulls for calving performance. In such routine evaluations both stillbirth and calving difficulty, and both direct and maternal effects, should be included.