交直流弱磁场测量装置研究

设计一款基于磁阻传感器的交直流微弱磁场信号测量装置,系统地介绍了测量装置的软硬件设计原理。采用基于ARM 32位处理器的STM32F407控制芯片对传感器采样信号进行数据处理和保存,具有良好的浮点数运算能力。利用傅里叶变换对磁场信号作频谱分析计算信号频率,并利用最小二乘法对实验数据进行拟合,得到线性度较好的磁场强度换算公式。通过交直流磁场标定实验证明了测量装置具有较高的准确度,运行可靠,可应用于监测周围环境的磁场强度。     

Blind separation of fetal electrocardiograms by annealed expectation maximization

This work explores blind source separation of fetal electrocardiograms by annealed expectation maximization (AEM). The AEM method improves the traditional EM method by relaxation under an annealing process, which is recruited to avoid trappings of tremendous spurious local minima within an objective function that inversely measures quantitative performance of a demixing structure. The derived objective function depends on the demixing structure as well as a set of membership vectors that represent missing data toward encoding statistical dependency of retrieved independent sources. Under the annealing process, the derived E and M steps are iteratively performed to search for expectations of membership vectors and minimizers of the objective function. The state number of membership vectors is related to modulate discretization of observations. Its effects on extraction of fetal electrocardiograms and reliability of the AEM method for blind source separation are extensively explored by numerical simulations.     

Test of time reversal invariance with TRINE

The new detector TRINE (time reversal invariance neutron experiment) was developed to test the time reversal invariance in the neutron decay. The precision of former experiments can be improved by one order of magnitude with an improved proton detection, a better background suppression and an angular resolving measurement using multiwire proportional chambers in coincidence with plastic scintillators, and the higher neutron flux and polarization available today. The concept of the detector and the status of the project is discussed.     

空间的相关性演绎 ——探讨藤本壮介非线性思维下的弱建筑

藤本壮介作为日本当代建筑理论与实践探索的先锋人物,对建筑空间与人体行为之间的关系有着独到的设计创见。本文试图从非线性视角探寻其创作原点的由来,进而对设计思想和建筑作品进行深入解读。首先,阐述非线性科学对传统思维模式的颠覆;其次,以传统美学要素"秩序"为切入点,探讨藤本基于深层秩序美学追求的"关系性"建筑观;最后,结合案例从功能、空间、秩序、场所四个方面分析和总结其"弱建筑"设计理念和方法,以期对当代建筑创作思维与表达的多元化发展提供启发。     

预应力管桩不宜施工的地层

本文通过具体的实例,结合自己多年工作经验以及工作中出现问题的处理方法,从不同的专业角度来看待、理解、探讨我们现在所学的专业中难以理解的现象,从中找出那些不适合预应力管桩施工的地层,或者说预应力管桩施工中可能出现难以施工的地层,如何去避免,去解决,或者从源头去消除,使之今后不在类似发生。     

A unified presentation of some urn models

For a sequence ofm urns we investigate how the number of urns satisfying a certain condition (e.g., being empty) evolves in time when after each time unit a ball is thrown. We show for a variety of urn models that this process (suitably normalized) converges weakly to a Gaussian process. The first and third authors’ work was supported by the Austrian Science Foundation FWF, Grant P10187-MAT. The second author was also supported by the Austrian-French project AMADEUS No. 97049. Online publication September 22, 2000.     

弱极化法腐蚀速度测试仪的研制

阐述了弱极化区四点法测定金属腐蚀速度的基本理论,并依据这一理论研制了智能化腐蚀速度测试仪及其电化学传感器。应用该仪器于现场和实验室监测了土壤介质中的不同金属的腐蚀速度     

Slope stability problems of the weak rocks in the Asarsuyu pass of the Anatolian motorway

 The Anatolian motorwaythrough the Asarsuyu Valley passes across landslides formed in amphibolites, metagranites and metadiorites which have been extensively disturbed by past fault movements. The investigations indicated that the instabilities in the valley could affect the proposed motorway. An attempt was made to establish the shear strength values of the 1200×750×130 m Kom Rock Slide using the Hoek and Brown equation. The work indicated that this was not applicable in the highly sheared material along the major fault zones. 28 February 1998 · Accepted: 9 June 1998     

有色观测噪声背景下正弦信号参量估计的互谱Levinson方法

本文从理论上证明了互相关函数的Yule-Walker方程，并在此基础上提出了互谱AR模型参数估计的Levinson递推自满，该自满可有效地克服传统互谱估计的FFT方法和周期图法存在的谱分辩率低、谱估计方差大等缺点，仿真试验表明，该方法还可有效的克服有色观测噪声对测量精度的影响。