基于Lucene对文件全文检索的研究与应用

分析了Lucene的原理,针对Lucene的IndexReader、IndexSearcher、IndexWriter、Directory的各种不足,研究了不同优化方案,并通过重写源码中的QueryParser限制效率低下的通配符查询及模糊查询,提高了搜索响应速度,最后,文章研究了Lucene的多个应用领域.     

The Best of Both Worlds:Supply and Demand China''''s Role as a Source of Refractory Minerals for Global Markets

China has long been recognised as an importantsource of refractory raw materials for refractorymarkets worldwide. Bauxite, magnesia, fused a-lumina, and refractory clays in particular, havemaintained China' s strong position as the world'sleading supplier of these mineral. However, im-portant changes have taken place in the structure of     

Saddlepoint approximation based structural reliability analysis with non-normal random variables

The saddlepoint approximation (SA) can directly estimate the probability distribution of linear performance function in non-normal variables space. Based on the property of SA, three SA based methods are developed for the structural system reliability analysis. The first method is SA based reliability bounds theory (RBT), in which SA is employed to estimate failure probability and equivalent normal reliability index for each failure mode firstly, and then RBT is employed to obtain the upper and the lower bo...     

中学英语教学刍议

在中学英语教学中,要正确认识语言知识与语言运用能力的辩证关系,以高素质的教师为中间媒介,促进学生在掌握语言知识的前提下,向语言运用能力转化。同时,要克服听说读写脱节的问题,加强听说读写技能各个环节的训练,发挥最大的整体效应。     

中印重点垂直行业促进自动化的增长

当前,在一些重要的发展中国家,重点垂直行业很大程度带动了自动化市场的迅速增长。让我们看一下中国和印度这两个亚太区最重要国家的垂直行业情况,不难发现在自动化应用水平方面,很多垂直行业之间都有相似之处。例如在过程自动化市场,中国和印度最大的自动化用     

触头感应钎焊钎着率的研究

针对接触器触头的感应钎焊，研究了感应钎焊温度及钎焊间隙对钎着率的影响。找出了感应钎焊温度及钎焊间隙对钎着率的影响规律。研究表明钎焊温度、钎焊间隙的最佳配合是获得高钎着率的重要条件。     

Summarization on variable liquid thrust rocket engines

The technology actuality and development trend of variable thrust rocket engines at home and abroad are summarized. Key technologies of developing variable thrust rocket engines are analyzed. Development advices on developing variable thrust rocket engines that are adapted to the situation of our country are brought forward.     

Monaural Speech Separation Using Dual-Output Deep Neural Network with Multiple Joint Constraint

Monaural speech separation is a significant research field in speech signal processing. To achieve a better separation performance, we propose three novel joint-constraint loss functions and a multiple joint-constraint loss function for monaural speech separation based on dual-output deep neural network(DNN). The multiple joint-constraint loss function for DNN separation model not only restricts the ideal ratio mask(IRM) errors of the two outputs, but also constrains the relationship of the esti...     

On the tension necking of copper single crystal specimen under slip deformation mechanism

The tension necking of FCC copper single crystal specimen with a square cross section was analyzed under the slip deformation mechanism. The actual clamp manner of the specimen was modeled by setting correlative boundary condition,and the small angle deflection between tension loading axis and crystallography axis [100] was taken into account. The finite deformation numerical analysis of three-dimensional necking deformation for the specimen was performed by apply-ing crystal plasticity theory associated with a numerical algorithm suggested by the first author. According to the comparison with experimental observation,the fact was confirmed that the numerical results could describe the loading elongation curve of the copper single crystal specimen under large strain tension reasonably,and the method could be used to investigate the necking characteristic in neck shape and the effect due to the small angle deflection. Further,the investigation into the influence of specimen cross-section shape on necking was also performed;the results on mechanical response and neck profile evolution obtained through modeling of cylindrical specimen were compared with those obtained with square cross-section specimen.     

Noise Analysis of Analog Correlator

A noise model for the analog correlator used in the ultra wideband receivers is proposed due to lack of simulation capability on noise performance of the correlator in current EDA tools.The analog correlator circuit is divided into several parts to calculate the equivalent noise sources respectively.The ideal impulse generators,instead of the noise sources,are then applied to obtain the time varying transfer functions.Fourier transforms are carried out to explore the relationship between the noise input and output in frequency domain for each part.Then the symmetrical noise sources are grouped together and the periodicity of the circuit is utilized to further simplify the model.This model can be used to evaluate noise performance of the correlator.