完全判别分析

针对现有的线性判别分析算法中存在的降维舍弃空间的判别信息丢失问题,以及秩空间和零空间的判别信息难以兼顾的问题,本文提出了一种完全判别分析算法.算法通过新构建一个子空间以及其中的判别矩阵,实现了可以充分使用全空间的判别信息;且新空间的维数较低,算法流程简单,计算代价较小.相关实验结果证实了本文算法较传统判别分析算法有更好的性能和效率.     

用于空间技术的刚-挠结合型封装基板

介绍了刚-挠结合型印制电路板封装技术的原理、做法和在空间技术中应用的重要意义。     

Forced-convergence decoding for LDPC-coded modulation

Low-density parity-check(LDPC)-coded modulation has attracted much attention for its outstanding performance in a bandwidth-limited channel.However,it involves relatively high decoding complexity.Owing to different convergence behaviors of variable nodes,the nodes detected early can be deleted from the Tanner graph,which reduces the size of the parity-check matrix iteration by iteration and thus the decoding complexity.In this paper,we propose a new decoding algorithm for LDPC-coded modulation with reduced complexity.In addition,by deleting the converged bits from the modulation constellation and updating the bit metrics of the demapper with the reduced constellation,more accurate estimation of the bits can be achieved.Simulation results show that,compared with conventional decoding schemes,the proposed method not only greatly reduces the overall decoding complexity for LDPC-coded modulation but also significantly improves decoding performance.     

用于PWB、HDI和先进封装的新型无卤基材

近些年来，印制电路板业界对环境保护的要求迅速升温。该公司已经开发并掌握了无卤核心技术。包括树脂体系技术和高填充量控制技术。作为树脂技术。开发了一种新型的树脂体系（RO树脂），它的特点是将大量的氮引入到分子主链结构中：而高填充量控制技术的核心则是开发了一种新的填料界面控制系统（FICS），它能使填料有足够高的分散度。采用这些技术．可以制成符合要求的多种无卤型基材。包括MCL-RO-67G．（下面讨论的TL-A）．用作多层PWB的薄型层压板MCF-4000G（后面将讨论的HD-B），用于高密度互连的增层法基材MCL-E-679F（G）（文章中讨论的HiTg），以及用于先进芯片塑料封装（PKGs）的高Tg层压板和PWB。这些基材有着优异的耐热性，并且很适合于无铅焊锡互连。与通用的基材相比。这些基材对于温度、潮湿和频率有着更好的稳定性。采用这些新型基材使环保型产品的设计、制造变得非常之容易。该公司还正在研发不久的将来所需要的适用于高频、高速、高可靠性PWB基材以及新型封装用基材。     

Variations of the relativistic electron flux after a magnetospheric compression event

On January 21, 2015, a sharp increase of the solar wind dynamic pressure impacted the magnetosphere. The magnetopause moved inward to the region L 8 without causing a geomagnetic storm. The flux of the relativistic electrons in the outer radiation belt decreased by half during this event based on the observations of the particle radiation monitor(PRM) of the fourth of the China-Brazil Earth Resource Satellites(CBERS-4). The flux remained low for approximately 11 d; it did not recover after a small magnetic storm on January 26 but after a small magnetic storm on February 2. The loss and recovery of the relativistic electrons during this event are investigated using the PRM data, medium-and high-energy electron observations of NOAA-15 and the Van Allen Probes, medium-energy electron observations of GOES-13, and wave observations of the Van Allen Probes. This study shows that the loss of energetic electrons in this event is related to magnetospheric compression. The chorus waves accelerate the medium-energy electrons, which causes the recovery of relativistic electrons. The Van Allen Probes detected strong chorus waves in the region L =3–6 from January 21 to February 2. However, the flux of medium-energy electrons was low in the region. This implies that the long-lasting lack of recovery of the relativistic electrons after this event is due to the lack of the medium-energy"seed" electrons. The medium-energy electrons in the outer radiation belt may be a clue to predict the recovery of relativistic electrons.     

多源数据更新空间数据库的方法研究

对如何利用各种来源的地理信息数据,更新城市基础空间数据库的方法进行了研究。在方法中,通过对各种数据源的分析,大体将数据源分为CAD及文本两大类,利用FME技术,分别实现对CAD及文本两大类数据的读取和转换,并结合dwg和xls两个示例,详细介绍了数据处理过程。本方法呈现出开放性、自动化程度高的特点,减少了人工劳动强度,极大地提高了数据库的更新质量及稳定性。     

基于AOP的Web系统权限管理

为了把影响多个模块的行为封装到一个单独的可重用模块中,使系统拥有更好的模块化、可扩展性和可维护性,面向方面编程(AOP:AspectOrientedProgramming)是一种行之有效的方法。介绍了AOP的基本概念并举例说明SpringAOP在Web系统中权限管理开发的具体应用。实践表明,在Web系统中应用AOP后,系统的核心业务逻辑和安全权限逻辑分开,从而使系统的耦合性大大降低且易于扩展。     

The molecular dynamics of neural metabolism during the action potential

Neural information processing is tightly coupled to both energy consumption and derivation from substrates.In this study,the energy function of the neuron during the action potential(AP)is described and analyzed.It has been observed that energy consumption during the AP does not match predictions of the conventional theory of neural energy dynamics.On short time scales,neural energy expenditure shifts between positive and negative phases.During the AP,the energy source switches from neuronal stores(positive expenditure or net consumption)to exploitation of external substrates,specifically the glucose and oxygen carried in cerebral blood(the negative consumption phase).Based on the idea of reductionism,this paper demonstrates how ion channels,membrane pumps and transporters,ionotropic and metabotropic receptor signaling pathways,astrocyte glycolysis and the production lactate,and the glutamate-glutamine cycle all serve to relate cerebral blood flow and neuronal metabolism to neuronal activity and so maintain neuronal energy charge during the AP.     

环氧基材PCB对无铅焊锡装配适应性的研究

讨论了环氧基材PCB对无铅焊锡装配的适应性、铜竭顶的可靠性，证明双氰胺固化的环氧基材不能适直无铅焊锡装配：酚醛树脂固化的环氧基材有解决此问题可能性，但都是PCB制造商们的技术决窍。