A novel bits loading algorithm for adaptive modulation OFDM multimode fiber communication system

A novel bits loading algorithm is proposed for adaptively modulated optical OFDM (AMOOFDM) multimode fiber communication system to decrease the system bit error rate (BER) caused by some OFDM subcarriers located at the deep nulls in the high frequency region of multimode fiber. The simulation results show that the performance of the new algorithm is approximate to the optimal algorithm-Greedy algorithm, but its computational complexity is considerably lower, thus the new algorithm is easy to implement. Comparing to fixed bits loading, adaptive bits loading can reduce the system BER effectively.     

A hybrid heuristic ordering and variable neighbourhood search for the nurse rostering problem

This paper is concerned with the development of intelligent decision support methodologies for nurse rostering problems in large modern hospital environments. We present an approach which hybridises heuristic ordering with variable neighbourhood search. We show that the search can be extended and the solution quality can be significantly improved by the careful combination and repeated use of heuristic ordering, variable neighbourhood search and back-tracking. The amount of computational time that is allowed plays a significant role and we analyse and discuss this. The algorithms are evaluated against a commercial Genetic Algorithm on commercial data. We demonstrate that this methodology can significantly outperform the commercial algorithm. This paper is one of the few in the scientific nurse rostering literature which deal with commercial data and which compare against a commercially implemented algorithm.     

原子荧光法测定甘草中汞

利用还原气化的非色散型装置，以湿法消解的方式，对中药甘草中的痕量汞进行了原子荧光测定。研究了影响测定结果的条件，比较了两种玻璃仪器的洗涤方式，并以工作曲线法和加入作图法对照，试验回收率在86．9％－110．8％，误差＜13．1％，得出了满意的分析结果。     

B -值白噪声广义泛函的解析刻画

Banach空间值白噪声广义泛函是一类重要的向量值白噪声广义泛函. 该文建立了Banach空间值白噪声广义泛函的一个解析刻画定理, 并给出了此结果的若干应用.     

变质CH13钢中Ce_2O_3异质核心作用的研究

采用变质处理大大减弱了CH13钢枝晶组织的元素偏析 ,使未变质CH13钢中的晶界碳化物得以消除 ,CH13钢的冲击韧性大大提高。通过热力学计算及二维点阵错配度计算 ,并采用电子探针定量分析等手段 ,证实Ce2 O3型稀土夹杂物可作为CH13钢中初生奥氏体的异质核心 ,细化枝晶组织 ,减弱合金元素偏析     

氨基酸及其衍生物的手性识别研究进展

本文综述了近年来开拓的多种人工受体模型对氨基酸及其衍生物的对映选择性识别性能，并做了相互比较，从中总结出手性识别的几个基本原则，预期了其应用前景。