Detection of K in soil using time-resolved laser-induced breakdown spectroscopy based on convolutional neural networks

One of the technical bottlenecks of traditional laser-induced breakdown spectroscopy (LIBS) is the difficulty in quantitative detection caused by the matrix effect. To troubleshoot this problem, this paper investigated a combination of time-resolved LIBS and convolutional neural networks (CNNs) to improve K determination in soil. The time-resolved LIBS contained the information of both wavelength and time dimension. The spectra of wavelength dimension showed the characteristic emission lines of elements, and those of time dimension presented the plasma decay trend. The one-dimensional data of LIBS intensity from the emission line at 766.49 nm were extracted and correlated with the K concentration, showing a poor correlation of R²_c=0.0967, which is caused by the matrix effect of heterogeneous soil. For the wavelength dimension, the two-dimensional data of traditional integrated LIBS were extracted and analyzed by an artificial neural network (ANN), showing R²_v=0.6318 and the root mean square error of validation (RMSEV)=0.6234. For the time dimension, the two-dimensional data of time-decay LIBS were extracted and analyzed by ANN, showing R²_v=0.7366 and RMSEV=0.7855. These higher determination coefficients reveal that both the non-K emission lines of wavelength dimension and the spectral decay of time dimension could assist in quantitative detection of K. However, due to limited calibration samples, the two-dimensional models presented over-fitting. The three-dimensional data of time-resolved LIBS were analyzed by CNNs, which extracted and integrated the information of both the wavelength and time dimension, showing the R²_v=0.9968 and RMSEV=0.0785. CNN analysis of time-resolved LIBS is capable of improving the determination of K in soil.     

顶板疏水快速回采工作面冲击地压机理 及防治措施

以某矿顶板疏水区下快速回采工作面冲击地压显现为工程背景,采用理论分析、数值模拟和现场监测等方法,研究不同回采速度下过顶板疏水区域时的超前支承压力分布规律,揭示顶板疏水快速回采工作面冲击地压发生机理:顶板富水区疏水后形成增压区与卸压区,当工作面快速回采经过疏水形成的增压区时,应力叠加易超过发生冲击地压的临界值,诱发回采工作面发生冲击。在此基础上提出了疏水增压区针对性的卸压措施以及疏水区域前后回采速度阶段调整的防冲方法。     

下套管技术在井下定向探放水孔中的应用

下套管是煤矿井下定向探放水钻孔施工中非常重要的一项工作,是后续定向钻进及放水能否安全、顺利实施的关键。结合工程实例,通过对下套管技术原理进行分析,提出相应的技术措施,形成一整套行之有效的下套管技术及配套钻具,为今后类似工程施工提供借鉴。     

工程造价咨询管理风险及防范措施

随着中国房地产市场经济的发展,建筑行业在全国的经济结构体系中的作用日益突出,工程造价咨询行业也随之快速发展,工程造价咨询管理企业业务量大幅增加,但管理风险也日益突出。工程项目风险的不确定性,使得工程造价面临各种各样的风险。通过分析咨询管理的风险种类、风险特点及风险产生的原因,提出风险防范流程、防范方法及应对措施,并结合工程实例进行了阐述。     

浅析双相钢空冷器的制造

通过一系列试验研究和对设备长周期运行数据的统计分析,得出了双相钢设备验收时不仅需要考核强度要求,而且应该考核抗腐蚀性能的结论。     

浅谈倘甸招商大厦隔震设计

国内高烈度地区连体结构采用隔震技术的实例较少，针对连体结构采用隔震技术以及上部连体结构设计时遇到的特殊问题作了分析探讨。提出了连体相关楼层楼板满足大震不屈服，连体结构大梁、桁架竖腹杆和斜腹杆满足中震不屈服的性能目标要求。     

浅析铝电解槽废旧阴极的综合利用

我国的电解铝产量大，随之每年就会产生大量的废旧阴极，不恰当地处理废旧阴极会对环境带来了巨大的危害，然而废旧阴极中含有许多工业上有用的物质。本研究将废旧阴极中的有害物质氟化物分解，并将氧化铝、炭、冰晶石、氟化钠等有用物质分离回收，不仅减轻了环境压力，而且还可以回收利用其中的有用物质。     

甘肃：食品安全案件不得以罚代刑

甘肃规定，食品安全监管部门在执法过程中如发现涉嫌犯罪案件应按规定及时做出移送公安机关处理的决定，并在决定做出后的24小时内向同级公安机关移送。     

清水混凝土模板技术应用例析

本文结合某高层住宅建筑施工实例，对混凝土模板施工技术进行了分析和总结，为同类工程提供参考。