Performance analysis of a COFDM/FM in-band digital audiobroadcasting system

In this paper, we present a performance analysis of a coded orthogonal frequency division multiplexing DAB system that is power multiplexed over a commercial FM station. We model the mobile channel with a time-frequency scattering function. Results show that the performance of the FM demodulator is crucial, since the level of the residual FM signal has a strong influence on the BER performance of the COFDM system. As with other mobile communication systems, the use of interleaving greatly enhances the performances     

Comparison of separation performance between single and two inlets hydrocyclones

Experimental studies have been carried out about the particle separation performance of single and two inlets hydrocyclones. Two types of hydrocyclones having the same total inlet holes area were examined. Hydrocyclone A (with single inlet hole) and hydrocyclone B (with two inlet holes) were used. An aqueous slurry of silica particles (0.5 wt% with a median diameter of about 2.1 μm) was tested using a 20 mm-diameter hydrocyclone with a 15% underflow ratio. It was found that the optimum flow rate which gives the highest separation performance of the hydrocyclone B is the same flow rate for each inlet. Usage of the hydrocyclone B indicated smaller cut size and higher particle collection efficiency compared to that of the hydrocyclone A, under the same flow rate or same pressure drop conditions. The time of flight model was used to predict the 50% cut size diameter for single inlet hydrocyclone, and the model was modified to the two inlets hydrocyclone. It was found that the calculated results agree well with the experimental results for the hydrocyclone A, and for the hydrocyclone B under the low total flow rates conditions.     

Begrenzung der Rissbreite nach Eurocode 2

Crack width control according to Eurocode 2 – Explanatory notes on factor k _c Reinforced concrete members are designed now according to EC2 [1]. A significant aspect is the determining of the minimum reinforcement area specified in section 7.3.2. Due to the shortened illustrations of the equations (7.1) and (7.2), the mechanical background is difficult to be highlighted. This often results in inaccurate use of the model parameters, which might lead to an unsafe design, particularly for members predominantly reinforced only by the minimum reinforcement. Therefore the mechanical background of the equations (7.1) and (7.2) is focused on in this contribution. Proper discussions and explanations might help the structural engineer in the practical design.     

论我国大城市中高校校园建设的走向

一座城市，尤其是具有悠久文脉的大城市，都会有一些著名的高等学府。本世纪末，随着我国城市化进程加快，城市品质不断提高，城市中原有的大学校园已远远不适应新世纪的教学、科研等多方面需求，形成了近几年高校校园改、扩建的浪潮。本文在我国跨世纪高校校园建设发展的走向，以及高等学府在城市中地位等问题上阐述了自己的观点。     

Optimization of large change tolerances of linear integrated circuits

Optimization of element tolerances is a very important but also time consuming part of integrated circuit design. In this paper an algorithm is presented for the worst case optimal assignment of large change tolerances, in which a significant simplification of the problem is obtained for a class of linear circuits. This is due to taking advantage of the bilinear dependence of the network functions on element values and to some simplifications assumed. The minimal cost of the circuit is the objective function.     

Zwangbeanspruchung massiver Kraftwerks‐Bodenplatten infolge der Hydratationswärme

Thermal restraint due to hydration heat in thick power plant slabs. Within the enlargement of the lignite‐fired power plant Boxberg by the block R, a measurement program was carried out in order to detect the thermal restraint in the thick slab due to the outflow of hydration heat. With the Finite Element Method thermal and mechanical relations during the hardening process were pointed out. Especially the real occurring restraint during the hardening process was investigated under different conditions. By material models depending on the hydration degree, a good agreement between calculation results and measurement was achieved. The results of this investigation were presented consecutively.