相干布居囚禁原子钟技术及其进展

分析了相干布居囚禁现象的基本原理,介绍了基于相干布居囚禁现象实现的两种原子钟实验装置的原理和结构,分析了各自的特点,并介绍了它们的研究进展以及应用前景。     

The search for neutrino–antineutrino mixing resulting from Lorentz invariance violation using neutrino interactions in MINOS

We searched for a sidereal modulation in the rate of neutrinos produced by the NuMI beam and observed by the MINOS far detector. The detection of such harmonic signals could be a signature of neutrino–antineutrino mixing due to Lorentz and CPT violation as described by the Standard-Model Extension framework. We found no evidence for these sidereal signals and we placed limits on the coefficients in this theory describing the effect. This is the first report of limits on these neutrino–antineutrino mixing coefficients.     

便携式X荧光分析仪在萤石矿勘查中的应用

在赤峰市林西县水头萤石矿区,利用便携式X荧光分析仪对第四系浅覆盖区进行隐伏萤石矿体探测的有效性试验。通过测量数据分析及与已知矿体的对比证明,在浅覆盖区利用X荧光分析仪勘查隐伏萤石体是有效的。该结论为便携式X荧光仪在勘查隐伏萤石矿体中的应用提供了重要依据。     

The potential of portable luminescence readers in geomorphological investigations: a review

The development of functional portable optically stimulated luminescence (OSL) readers over the last decade has provided practitioners with the capability to acquire luminescence signals from geological materials relatively rapidly, which allows for expedient preliminary chronostratigraphic insight when working with complex depositional systems of late Quaternary age. Typically, when using the portable OSL reader, infrared (IR) or blue post-IR OSL signals are acquired from bulk unprocessed materials, in contrast to regular luminescence dating, which is usually based on measurements on pure quartz or feldspar mineral separates, or on select silt-sized polymineralic portions. To demonstrate the utility of portable OSL measurements, this paper outlines the basic features of portable OSL readers and their constraints. Subsequently, case studies in which the instrument has been used to elucidate cryptostratigraphic variations in sedimentary sequences for geomorphological applications are reviewed. The studies can generally be grouped into three main categories. The first includes studies where the variation of portable OSL reader luminescence signal intensities with depth are plotted to generate profiles that contextualize sediment stratigraphy. In the second group, portable OSL reader luminescence signal intensities are used to interpret sediment processes that shed light on depositional histories. In the last category, luminescence signals from the portable OSL reader are calibrated to approximate numerical burial ages of depositional units. The paper concludes with a discussion of possible future directions. © 2020 John Wiley & Sons, Ltd.     

PC-2000型活性炭氡测量仪

PC--2000型活性炭氡测量仪是由便携式工控机支持的用于测量活性炭吸附氡子体γ的高科技新产品：本文介绍了PC-2000型活性炭氡测量仪的用途、结构、原理、技术性能与使用方法。     

海床式静力触探在黄河口海底土工程特性研究中的应用

海床式静力触探设备工作效率高,能够实现从垂向上对地层的连续探测,数据分辨率较好。通过对黄河口海域3个静力触探孔和1个地质钻孔的分析,将研究区20m以浅地层自上而下划分为粉土、粉质黏土、粉土夹粉砂或粉砂、粉质黏土、粉土五层,静力触探曲线对粉土层中的硬壳层和粉质黏土层中的贝壳夹层等特殊地质现象有很好的反映。对粉质黏土的静力触探参数与物理力学参数进行相关性分析,得到适合该区域的回归方程。采用基于CPT数据的液化判别法,对研究区表层粉土液化可能性进行评判,通过Seed简化法计算的周期应力比(CSR)与Olsen法计算的周期阻力比(CRR)的大小比较,得出当抗震设防烈度为7度时,研究区表层粉土不会液化,当抗震设防烈度为8度时,粉土层将发生液化,计算最大液化深度3.7m。     

A CPT-based model to predict the installation torque of helical piles in sand

Helical piles present a possible alternative to driven displacement piles in the offshore sector. While this type of pile is used widely in the onshore environment, design methods tend to be highly empirical and there is considerable uncertainty around the bearing resistance and the installation resistance required to install large diameter piles necessary to resist uplift. The paper combines a theoretical model for estimating torque resistance from the literature with a cone penetration test (CPT)-based model originally developed to estimate the axial resistance of helical piles and to predict the installation torque required to install piles in sand. The model appears to be able to capture the general installation behavior of piles across a range of scales and in various sand states.     

静力触探实验数据库的建立及土体参数相关性分析

静力触探实验以其连续性、重现性好及可靠性高等优点在现场实验中得到广泛的应用,但目前国内外对于其实验数据的数字化管理及其相关性分析方面的研究仍然较少。借助VBA语言对Excel进行二次开发,建立了静力触探实验数据库。该数据库不但具有信息量大、操作简单、代码开放等特点,而且具有随着库中数据量的丰富,其分析结果可靠性越高的优点。并且以该库中的上海地区18个工程项目的岩土工程勘察的实验数据为基础,分别对静力触探实验比贯入阻力B与土的压缩模量B、固结快剪指标（Ccq、φcq）、以及三轴固结不排水指标（Ccu、φcu）做了相关性分析,得到三组关系式。对这几组关系式的显著性检验的结果表明相关性很好,可为地层条件与上海地区类似的工程设计作为参考依据。     

基于单片机的多功能手持GPS定位仪的设计

介绍基于STC89C52单片机下的GPS信息的接收及输出显示,并利用SD卡对导航数据进行保存。采用GPS模块接收卫星信号,通过串口连接,既可通过单片机处理,然后在TFT彩屏上显示相关信息,也可与PC机通信,通过PC机应用软件显示GPS信息,也可通过PC版灵图电子地图实现实时导航。将SD卡保存的数据经GPSBabel软件转换,在googel earth地图上实现轨迹重现。实际应用效果表明,该设计合理有效,具有很高的实用价值。     

Application of Dynamic Compaction in Highway: A Case Study

The application case of dynamic compaction (DC) is realized in highway. In this paper, the in situ tests for evaluating effectiveness of DC are performed on a liquefiable soil and soft soil interbedding foundation encountered in highway engineering practice. Excess pore pressure, total surface settlement and lateral deformation under DC impact are measured and analysed. The cone penetration test (CPT) and spectral analysis of surface wave (SASW) are used for investigating the compaction effectiveness. The formulation of the predicting improvement depth of the DC is presented according to the pseudo-static mechanics method and is of obvious meaning of soil mechanics compared with Mendard’s formulation. The calculating results of the formulation of improvement depth of the DC are agreement with the measuring results. The investigation results indicate that the DC technique is an effective way for improving liquefiable soil and soft soil interbedding foundation in highway engineering practice.