Review of methodological and experimental LIBS techniques for coal analysis and their application in power plants in China

Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical spectroscopy technique. This review presents the main recent developments in China regarding the implementation of LIBS for coal analysis. The paper mainly focuses on the progress of the past few years in the fundamentals, data pretreatment, calibration model, and experimental issues of LIBS and its application to coal analysis. Many important domestic studies focusing on coal quality analysis have been conducted. For example, a proposed novel hybrid quantification model can provide more reproducible quantitative analytical results; the model obtained the average absolute errors (AREs) of 0.42%, 0.05%, 0.07%, and 0.17% for carbon, hydrogen, volatiles, and ash, respectively, and a heat value of 0.07 MJ/kg. Atomic/ionic emission lines and molecular bands, such as CN and C₂, have been employed to generate more accurate analysis results, achieving an ARE of 0.26% and a 0.16% limit of detection (LOD) for the prediction of unburned carbon in fly ashes. Both laboratory and on-line LIBS apparatuses have been developed for field application in coal-fired power plants. We consider that both the accuracy and the repeatability of the elemental and proximate analysis of coal have increased significantly and further efforts will be devoted to realizing large-scale commercialization of coal quality analyzer in China.     

Assessment of LIBS for Spectrochemical Analysis: A Review

Abstract

This review assesses the applications of laser-induced breakdown spectroscopy (LIBS) for the analysis of a variety of samples, including biomaterials (teeth, nail, hair, gallstones, and kidney stones, etc.), food materials (fruits and vegetables, milk, salt, nutritional supplements, etc.), medicinal plants, industrial waste, liquid samples, etc. In addition, for the first time the identification of cholesterol and pigment stones was performed on the basis of atomic lines of different elements and molecular bands of C₂ molecules present in the LIBS spectra of gallstones. Chemometric techniques such as principal component analysis (PCA) was also applied to LIBS data for rapid identification/classification of different gallstone samples. LIBS analysis of toxic/heavy elements present in vegetables (spinach, tomato) and rice is also presented in this review. It was observed that vegetables grown near industrial areas are rich in several toxic metals like Pb and Cr. The wastewater samples from different industries were also analyzed by recording their spectra using a liquid jet. These results clearly demonstrate the ability of LIBS technique as an instant monitoring device to detect heavy metals present in liquid samples. Finally, this review shows that LIBS is a versatile analytical technique with unlimited applications.     

Cold nuclear fusion

Recent accelerator experiments on fusion of various elements have clearly demonstrated that the effective cross-sections of these reactions depend on what material the target particle is placed in. In these experiments, there was a significant increase in the probability of interaction when target nuclei are imbedded in a conducting crystal or are a part of it. These experiments open a new perspective on the problem of so-called cold nuclear fusion.     

虚拟仪器在核技术实验教学中的应用探索

核技术与核安全是一门实践性很强的学科,实验教学是核技术专业人才培养的关键环节.本文介绍了传统核技术相关实验教学的现状,探讨了基于虚拟仪器的核技术实验教学的特点,开发了的一套基于Lab VIEW的位置灵敏探测器虚拟实验教学系统,表明了虚拟仪器在核技术实验教学中应用的可行性,为缓解实验室压力提供了新的实验方法.     

A new scenario for the application of very intense lasers to nuclear fusion

The ponderomotive motion of a charged particle inside a Terawatt-Petawatt laser pulse is studied. Based on a very simple classical model to account for the Coulomb repulsion, the possibility of nuclear collisions in the keV-MeV range is shown. Also, a simple analytical expression for the minimum internuclear distance is given. Since this range of energies is significant to trigger nuclear fusion reactions, this may result in an alternative approach to controlled fusion based on a non-thermalized plasma. The proposed system works for the deuterontriton fusion reaction, but is more appropriate for other reactions like the proton-⁷Li reaction, and also like the ecologically clean, boron-¹¹B reaction.     

激光核聚变光学元件超精密加工技术的研究

论述了脆性材料延性加工机理。应用超精密加工技术解决了激光核聚变光学元件的大批量加工问题。研究了平面光学元件、KDP晶体和方形透镜超精密加工技术,给出了这三类光学元件超精密加工的工艺过程、机床设计准则和最佳工艺参数。     

Recent progress on the application of LIBS for metallurgical online analysis in China

Recent progress on the application of laser-induced breakdown spectroscopy (LIBS) for metallurgical analysis particularly achieved by Chinese research community is briefly reviewed in this article. The content is mainly focused on the progress in experimental research and calibration methods toward LIBS applications for metallurgical online analysis over the past few years. Different experiment setups such as single-pulse and double-pulses LIBS schematics are introduced. Various calibration methods for different metallic samples are presented. Quantitative results reported in the literature and obtained in the analysis of various samples with different calibration methods are summarized. At the last section of this article, the difficulties of LIBS application for molten metal analysis in a furnace are discussed.     

核聚变中的核物理问题

采用标准的量子力学方位阱加库伦位垒,计算了氘-氘聚变截面。给出了0．2～280keY能区内的截面数据。与实验符合得很好。此模型说明了不可用Breit-Wigner公式来讨论轻核聚变反应。将此模型运用于束缚态带电粒子之间的核反应。可以解释一系列“异常现象”。并展现了开发不带强放射性的聚变能的前景。     

From lightning to nuclear fusion

Topological defects are common in many everyday systems. In general, they appear if a symmetry is broken at a rapid phase transition. In this article, I explain why it is believed that they should have also been formed in the early universe and how that would have happened. If topological defects are found, this will provide a way to study observationally the first fractions of a second after the Big Bang, but their apparent absence can also tell us many things about the early universe.     

Beta-delayed neutron spectra for application in reactor technology,nuclear physics and astrophysics

Recent developments in ß-delayed neutron (DN) spectroscopy are reviewed, and the importance of DN energy spectra for various problems in reactor physics, nuclear physics and astrophysics is discussed.     

Deuterium transport and isotope effects in type 316L stainless steel at high temperatures for nuclear fusion and nuclear hydrogen technology applications

We present the first complete data set for the permeability, diffusivity, and solubility of both deuterium and hydrogen in 316L stainless steel (316L SS) obtained over a wide temperature range of 350–850 °C that accommodates both nuclear fusion and nuclear hydrogen technology applications. The deuterium results were also compared with the hydrogen results to estimate the isotope effect. The isotope effect ratio for diffusivity was different from the classical prediction. Furthermore, some of our results were compared with the results previously reported for 316 SS. Results and discussion are presented with an emphasis on the deuterium permeation and isotope effects.     

Search for cold nuclear fusion in palladium-deuteride

We searched for protons generated in cold D fusion reactions in Pd cathodes doped electrolytically with D. The applied experimental technique allowed the detection of proton production rates exceeding 0.074 s^–1 per cm³ cathode material (or 3.1·10^–24 s^–1 per D pair). Our results do not confirm fusion rates such like those recently reported.     

核对称轴不同相对取向对熔合动力学的影响

计算了核对称轴不同相对取向时的熔合位垒.基于双核模型观念，考虑了熔合与准裂变的竞争，通过数值法求解主方程，计算了⁷⁶Ge+²⁰⁸Pb，⁴⁸Ca+²⁴⁴Pu核对称轴不同相对取向对熔合概率的影响，探索了最有利于超重元素合成的弹靶相对取向.取向不同时，对熔合反应的影响较大，计算结果表明弹靶碰撞为腰对腰时，更有利于发生熔合反应. 关键词： 超重元素 熔合概率 变形核 方向角度     

Incomplete fusion and nuclear equation of state

A microscopic model based on the molecular dynamics concept was applied to study linear momentum transfer in nuclear reactions for a range of incident energies and several systems. It appears that this quantity is sensitive to the incompressibility of nuclear matter. The comparison of the model calculation with a substantial body of data favors a soft equation of state (K=200MeV).     

Time-dependent nuclear measurements of mix in inertial confinement fusion

The first time-dependent nuclear measurements of turbulent mix in inertial confinement fusion have been obtained. Implosions of spherical deuterated-plastic shells filled with pure 3He gas require atomic-scale mixing of the shell and gas for the D-3He nuclear reaction to proceed. The time necessary for Rayleigh-Taylor (RT) growth to induce mix delays peak nuclear production time, compared to equivalent capsules filled with a D2-3He mixture, by 75+/-30 ps, equal to half the nuclear burn duration. These observations indicate the likelihood of atomic mix at the tips of core-penetrating RT spikes.     

A theory of cold nuclear fusion in deuterium-loaded palladium

Deuterium gas compressed in a palladium lattice is considered to form a quantum plasma of bosons leading to significant screening of the Coulomb potential between deuterium ions. The resulting enhancement of the quantum mechanical tunnelling probability adequately explains the recently observed cold fusion rates.     

Review of Japanese fusion program and role of inertial fusion

The high compression of 600 times liquid density and the recent fast heating of a compressed core to 1-keV temperature have provided proof-of-principle of the fast ignition concept, and these results have significantly contributed to approve first phase of the Fast Ignition Realization EXperiment (FIREX) project. The goal of FIREX-I is to demonstrate fast heating of a fusion fuel up to the ignition temperature of 5–10 keV. Although the fuel size of FIREX-I is too small to ignite, sufficient heating will provide the scientific viability of ignition-and-burn by increasing the laser energy thereby the fuel size. Based on the result of FIREX-I, the decision of the start of FIREX-II to achieve ignition-and-burn can be made. The FIREX program is under the collaboration of the Institute of Laser Engineering and the National Institute for Fusion Science.     

基于多信号融合技术的武器系统综合检查仪的研制与实现

根据国内目前先进军用飞机武器系统的测试需求,采用PCI平台和虚拟仪器控制技术开发了一套新型武器系统综合检查仪。该检查仪采用独特的设计方法,硬件上采用扩展性良好的一体化PCI工控机,同时用各种适配电路对众多的武器信号分类,进行归一化处理和融合,软件上进行模块化设计。应用结果表明,该武器系统综合检查仪运行稳定可靠,测试效率高,具有很强的实用性和推广价值。     

彩色融合技术在军事中的应用

采用基于l空间的色彩传递理论实现实时的红外与可见光彩色融合技术,并介绍了自行研制的红外与微光彩色融合系统的组成和工作流程。介绍了彩色融合技术在军事中的典型应用:夜间狙击手探测和伪装车辆探测,并给出了实验图像。设计了一种图像中目标探测性的主观评价方法,并对两组实验图像进行了评价。实验结果表明,彩色融合技术能够大大提高军事目标的探测性。