Observation and Analysis of VLF Nocturnal Multimode Interference Phenomenon based on Waveguide Mode Theory

Very low frequency(VLF)signals are propagated between the ground-ionosphere.Multimode interference will cause the phase to show oscillatory changes with distance while propagating at night,leading to abnormalities in the received VLF signal.This study uses the VLF signal received in Qingdao City,Shandong Province,from the Russian Alpha navigation system to explore the multimode interference problem of VLF signal propagation.The characteristics of the effect of multimode interference phenomena on the phase are analyzed according to the variation of the phase of the VLF signal.However,the phase of VLF signals will also be affected by the X-ray and energetic particles that are released during the eruption of solar flares,therefore the two phenomena are studied in this work.It is concluded that the X-ray will not affect the phase of VLF signals at night,but the energetic particles will affect the phase change,and the influence of energetic particles should be excluded in the study of multimode interference phenomena.Using VLF signals for navigation positioning in degraded or unavailable GPS conditions is of great practical significance for VLF navigation systems as it can avoid the influence of multimode interference and improve positioning accuracy.

Experimental research and energy analysis of a new type of dry ice powder pneumatic rock breaking technology

When the traditional drill and blast method is applied to rock crushing projects,it has strong vibration,loud noise and dust pollution,so it cannot be used in densely populated areas such as urban public works.We developed a supercritical CO_(2)true triaxial pneumatic rock-breaking experimental system,and conducted laboratory and field tests of dry ice powder pneumatic rock-breaking.The characteristics of the blast-induced vibration velocity waveform and the evolution of the vibration velocity and frequency with the focal distance were analyzed and discussed.The fracturing mechanism of dry ice powder pneumatic rock breaking is studied.The research results show that:(1)The vibration velocity induced by dry ice powder pneumatic rock breaking decays as a power function with the increase of the focal distance;(2)The vibration frequency caused by dry ice powder pneumatic rock breaking is mainly distributed in 1–120 Hz.Due to the dispersion effect,the dominant frequency of 10–30 Hz appears abnormally attenuated;(3)The traditional CO_(2)phase change fracturing energy calculation formula is also applicable to dry ice pneumatic rock breaking technology,and the trinitrotoluene(TNT)equivalent of fracturing energy is applicable to the Sadovsky formula;(4)Dry ice powder pneumatic rock breaking is shock wave and highenergy gas acting together to fracture rock,which can be divided into three stages,among which the gas wedge action of high-energy gas plays a dominant role in rock mass damage.

Numerical analysis of matrix swelling and its effect on microstructure of digital coal and its associated permeability during CO_(2)-ECBM process based on X-ray CT data

Matrix swelling effect will cause the change of microstructure of coal reservoir and its permeability,which is the key factor affecting the engineering effect of CO_(2)-ECBM technology.The Sihe and Yuwu collieries are taken as research objects.Firstly,visualization reconstruction of coal reservoir is realized.Secondly,the evolution of the pore/fracture structures under different swelling contents is discussed.Then,the influence of matrix phase with different swelling contents on permeability is discussed.Finally,the mechanism of swelling effect during the CO_(2)-ECBM process is further discussed.The results show that the intra-matrix pores and matrix-edge fractures are the focus of this study,and the contacting area between matrix and pore/fracture is the core area of matrix swelling.The number of matrix particles decreases with the increase of size,and the distribution of which is isolated with small size and interconnected with large size.The swelling effect of matrix particles with larger size has a great influence on the pore/fracture structures.The number of connected pores/fractures is limited and only interconnected in a certain direction.With the increase of matrix swelling content,the number,porosity,width,fractal dimension,surface area and volume of pores/fractures decrease,and their negative contribution to absolute permeability increases from 0.368% to 0.633% and 0.868%-1.404%,respectively.With the increase of swelling content,the number of intra-matrix pores gradually decreases and the pore radius becomes shorter during the CO_(2)-ECBM process.The matrix continuously expands to the connected fractures,and the width of connected fractures gradually shorten.Under the influence of matrix swelling,the bending degree of fluid flow increases gradually,so the resistance of fluid migration increases and the permeability gradually decreases.This study shows that the matrix swelling effect is the key factor affecting CBM recovery,and the application of this effect in CO_(2)-ECBM process can be discussed.

Elemental composition x-ray fluorescence analysis with a TES-based high-resolution x-ray spectrometer

The accurate analysis of the elemental composition plays a crucial role in the research of functional materials.The emitting characteristic x-ray fluorescence(XRF)photons can be used for precisely discriminating the specified element.The detection accuracy of conventional XRF methodology using semiconductor detector is limited by the energy resolution,thus posing a challenge in accurately scaling the actual energy of each XRF photon.We adopt a novel high-resolution x-ray spectrometer based on the superconducting transition-edge sensor(TES)for the XRF spectroscopy measurement of different elements.Properties including high energy resolution,high detection efficiency and precise linearity of the new spectrometer will bring significant benefits in analyzing elemental composition via XRF.In this paper,we study the Ledge emission line profiles of three adjacent rare earth elements with the evenly mixed sample of their oxide components:terbium,dysprosium and holmium.Two orders of magnitude better energy resolution are obtained compared to a commercial silicon drift detector.With this TES-based spectrometer,the spectral lines overlapped or interfered by background can be clearly distinguished,thus making the chemical component analysis more accurate and quantitative.A database of coefficient values for the line strength of the spectrum can then be constructed thereafter.Equipped with the novel XRF spectrometer and an established coefficient database,a direct analysis of the composition proportion of a certain element in an unknown sample can be achieved with high accuracy.

Energy-dispersive X-ray Spectroscopy for the Quantitative Analysis of Pyrite Thin Specimens

To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantitative analysis of pyrite materials.Additionally,the k factor of pyrite is calculated experimentally.To develop an appropriate non-standard quantitative analysis model for pyrite materials,the experimentally calculated k factor is compared with that estimated from the non-standard quantitative analytical model of the instrument software.The experimental findings demonstrate that the EDS attached to a TEM can be employed for precise quantitative analysis of micro-and nanoscale regions of pyrite materials.Furthermore,it serves as a reference for improving the results of the EDS quantitative analysis of other sulfides.

X-ray Manifestations of Pneumoconiosis Patients and Differential Analysis with Pulmonary Tuberculosis

[Objectives]This study was conducted to explore the X-ray manifestations of pneumoconiosis patients and differentiation from pulmonary tuberculosis.[Methods]Retrospective analysis was conducted on 103 patients who underwent lung examinations,including 47 cases of pneumoconiosis and 56 cases of pulmonary tuberculosis.The differences in nodule characteristics and accompanying cavity sign between pneumoconiosis and pulmonary tuberculosis were compared.[Results]The X-ray manifestations of pneumoconiosis patients mainly included various forms of lung images,which were uneven in density,and had blurry edges,and sometimes thickening of lung markings and reduction of lung volume could be observed.The acinar nodules observed in X-ray films of patients with hematogenous disseminated pulmonary tuberculosis appeared petal like.The uniformity of nodule appearance such as nodule distribution,nodule density,and nodule size was significantly lower in pneumoconiosis than in hematogenous disseminated pulmonary tuberculosis,showing a statistical significance(P<0.05).The diameter of cavities in patients with pneumoconiosis accompanied by cavity sign[(0.64±0.13 vs 3.37±0.95)cm]was lower than that in patients with secondary pulmonary tuberculosis accompanied by cavity sign.There was a significant difference in the thickness of the cavity wall between the two diseases,and patients with pneumoconiosis accompanied by cavity sign had a higher rate of thick wall cavities(>3 mm).The X-ray manifestations of pneumoconiosis and tuberculosis were relatively similar,but the distribution,density and size of nodules in pneumoconiosis were relatively uneven,and the patients accompanied by cavity sign had smaller cavity diameter and higher rate of thick-walled cavities.[Conclusions]This study provides a reference for the clinical differential diagnosis of pneumoconiosis and pulmonary tuberculosis.

Research Hotspot and Trend Analysis of Wuling Powder Based on CiteSpace

[Objectives]This study was conducted to systematically present the research and development status of Wuling Powder over the years, and comprehensively analyze the hot spots and trends of Wuling Powder in the treatment of diseases, so as to provide reference for scholars in this field in the future. [Methods] China National Knowledge Network(CNKI) database was used as the literature retrieval source to search the literature related to Wuling Powder in the treatment of nephropathy, and then the data visualization analysis was carried out by using the software citespace.5.7.R2. [Results] Through accurate retrieval, a total of 204 effective literatures were included. It was found that domestic research on the treatment of nephropathy by Wuling Powder was on the rise. From the analysis of knowledge graph, it was concluded that after long-term research and development, a relatively concentrated core research group had been formed in China, which mainly focused on "Wuling Powder", "chronic kidney disease" and "diabetic nephropathy". [Conclusions] The research on the treatment of nephropathy by Wuling Powder shows a good development trend, and the research content is constantly enriched, and this research is still the current and future research hotspot.

Chemical Analysis of Hydroxyapatite Artificial Bone Powders by Energy Dispersive X-Ray Fluorescence Spectrometry(EDXRF)

Stoichiometric hydroxyapatite(HA)nanoparticles were synthesized by a wet chemical method.Calcium nitrate tetra hydrate used as calcium source and dibasic ammonium phosphate used as phosphorous source.Calcium nitrate tetra hydrate and dibasic ammonium phosphate solutions were prepared by dissolving the salts in distilled water.Stoichiometric hydroxyapatite nanoparticles used by artificial bone powders and synthesized by a wet chemical method were analyzed using EDXRF method.The concentrations of K,Ca,Ti,V,Cr,Fe,Ni,Cu,Sr and Pb for artificial bone powders have been determined.Besides,Calcium contents were evaluated according to the agitation time and temperature in the production process.

Use of high-resolution X-ray computed tomography and 3D image analysis to quantify mineral dissemination and pore space in oxide copper ore particles

Mineral dissemination and pore space distribution in ore particles are important features that influence heap leaching performance. To quantify the mineral dissemination and pore space distribution of an ore particle, a cylindrical copper oxide ore sample (I center dot 4.6 mm x 5.6 mm) was scanned using high-resolution X-ray computed tomography (HRXCT), a nondestructive imaging technology, at a spatial resolution of 4.85 mu m. Combined with three-dimensional (3D) image analysis techniques, the main mineral phases and pore space were segmented and the volume fraction of each phase was calculated. In addition, the mass fraction of each mineral phase was estimated and the result was validated with that obtained using traditional techniques. Furthermore, the pore phase features, including the pore size distribution, pore surface area, pore fractal dimension, pore centerline, and the pore connectivity, were investigated quantitatively. The pore space analysis results indicate that the pore size distribution closely fits a log-normal distribution and that the pore space morphology is complicated, with a large surface area and low connectivity. This study demonstrates that the combination of HRXCT and 3D image analysis is an effective tool for acquiring 3D mineralogical and pore structural data.

Quantitative energy-dispersive X-ray fluorescence analysis for unknown samples using full-spectrum least-squares regression

The full-spectrum least-squares(FSLS) method is introduced to perform quantitative energy-dispersive X-ray fluorescence analysis for unknown solid samples.Based on the conventional least-squares principle, this spectrum evaluation method is able to obtain the background-corrected and interference-free net peaks, which is significant for quantization analyses. A variety of analytical parameters and functions to describe the features of the fluorescence spectra of pure elements are used and established, such as the mass absorption coefficient, the Gi factor, and fundamental fluorescence formulas. The FSLS iterative program was compiled in the C language. The content of each component should reach the convergence criterion at the end of the calculations. After a basic theory analysis and experimental preparation, 13 national standard soil samples were detected using a spectrometer to test the feasibility of using the algorithm. The results show that the calculated contents of Ti, Fe, Ni, Cu, and Zn have the same changing tendency as the corresponding standard content in the 13 reference samples. Accuracies of 0.35% and 14.03% are obtained, respectively, for Fe and Ti, whose standard concentrations are 8.82% and 0.578%, respectively. However, the calculated results of trace elements (only tens of lg/g) deviate from the standard values. This may be because of measurement accuracy and mutual effects between the elements.

MULTI-PEAK MATCH INTENSITY RATIO METHOD OF QUANTI-TATIVE X-RAY DIFFRACTION PHASE ANALYSIS

A new method for quantitative phase analysis is proposed by using X-ray diffraction multi-peak match intensity ratio. This method can obtain the multi-peak match intensity ratio among each phase in the mixture sample by using all diffraction peak data in the mixture sample X-ray diffraction spectrum and combining the relative intensity distribution data of each phase standard peak in JCPDS card to carry on the least square method regression analysis. It is benefit to improve the precision of quantitative phase analysis that the given single line ratio which is usually adopted is taken the place of the multi-peak match intensity ratio and is used in X-ray diffraction quantitative phase analysis of the mixture sample. By analyzing four-group mixture sample, adopting multi-peak match intensity ratio and X-ray diffraction quantitative phase analysis principle of combining the adiabatic and matrix flushing method, it is tested that the experimental results are identical with theory.

Comparative Analysis of the Multi-Frequency Bio-impedance and Dual-energy X-ray Absorptiometry on Body Composition in Obese Subjects

To examine accuracy of body composition predicted by the Multi-Frequency Bioelectric Impedance Analysis （MF-BIA） compared with the Dual-energy X-ray Absorptiometry （DXA） in adults with obese. We measured body composition of 749 adults with obese both by the MF-BIA and DXA. The Lin＇s concordance correlation and the Bland-Altman plots were used to examine the consistency. The concordance correlation coefficient of %BF between the MF-BIA and DXA in men and women was 0.560, and 0.669, respectively. Compared with the DXA, the MF-BIA significantly underestimated %BF by 4.33% in men （P 〈 0.001）, however overestimated %BF by 0.50% in women （P 〈 0.001）. After corrected by the correction equations established in this study, the differences were significantly decreased. Therefore, the MF-BIA （TANITA MC-180） may need to be corrected in estimating body composition for adults with obese.

Fabrication of Ti_2AlC by Spark Plasma Sintering from Elemental Powders and Thermodynamics Analysis of Ti-Al-C System

A ternary-layered carbide Ti2AlC material could be synthesized by spark plasma sintering（SPS） technology using elemental powder mixture of Ti, Al and active carbon. By means of XRD and SEM, phases were identified and microscopically evaluated. The experimental results show that the main phase in the product was fully crystallized Ti2AlC with small particle size when sintered at 1200℃. The synthesis temperature of SPS was 200-400℃ lower than that of hot pressing （HP） or hot isostatic pressing （HIP）. Through thermodynamics calculations, the mechanism of Ti2AlC was studied by calculating changes of Gibbs free energy of reactions.

Elemental and proximate analysis of coal by x-ray fluorescence assisted laser-induced breakdown spectroscopy

Although laser-induced breakdown spectroscopy(LIBS),as a fast on-line analysis technology,has great potential and competitiveness in the analysis of chemical composition and proximate analysis results of coal in thermal power plants,the measurement repeatability of LIBS needs to be further improved due to the difficulty in controlling the stability of the generated plasmas at present.In this paper,we propose a novel x-ray fluorescence(XRF) assisted LIBS method for high repeatability analysis of coal quality,which not only inherits the ability of LIBS to directly analyze organic elements such as C and H in coal,but also uses XRF to make up for the lack of stability of LIBS in determining other inorganic ash-forming elements.With the combination of elemental lines in LIBS and XRF spectra,the principal component analysis and the partial least squares are used to establish the prediction model and perform multi-elemental and proximate analysis of coal.Quantitative analysis results show that the relative standard deviation(RSD) of C is 0.15%,the RSDs of other elements are less than 4%,and the standard deviations of calorific value,ash content,sulfur content and volatile matter are 0.11 MJ kg,0.17%,0.79% and 0.41%respectively,indicating that the method has good repeatability in determination of coal quality.This work is helpful to accelerate the development of LIBS in the field of rapid measurement of coal entering the power plant and on-line monitoring of coal entering the furnace.

In vivo evaluation and mechanism prediction of anti-diabetic foot ulcer based on component analysis of Ruyi Jinhuang powder

BACKGROUND Diabetes is a metabolic disease with a high complication rate.Diabetic foot ulcers(DFUs)seriously affect the quality of life of patients.A total of 15%-20%of diabetic patients develop DFUs,which heal with difficulty over a long time and can result in amputation and disability.Traditional Chinese medicine has a unique effect in the treatment of skin ulcerative diseases.Ruyi Jinhuang powder(RHP)is one of the classic prescriptions in traditional Chinese medicine and is widely used in clinical practice.AIM To verify the ability of RHP to promote wound healing by electron microscopy analysis in animal models and hematoxylin-eosin(HE)staining.The effective components of RHP were extracted and identified by gas chromatography-mass spectrometry(GC-MS),and the obtained chemical components were analyzed by network pharmacology methods to predict its therapeutic mechanism.METHODS Sprague Dawley rats were injected with streptozotocin to establish the DFU model.HE staining was used to observe the wound tissue under an electron microscope.The chemical constituents of RHP were extracted first by supercritical fluid extraction and alcohol extraction,and then,GC-MS and ultra-performance liquid chromatography–MS were used to separately identify the chemical constituents.In addition,the"herb-component-target"link was established through the Traditional Chinese Medicine Systems Pharmacology database to obtain the target information,and the molecular docking of important components and key targets was performed in Discovery Studio software.Cytoscape software was used to visualize and analyze the relationship between the chemical composition,targets and Traditional Chinese Medicine network.RESULTS RHP promoted DFU healing in rats by affecting fibroblasts and nerve cells.A total of 89 chemical components were obtained by GC-MS.Network pharmacological analysis revealed that RHP was associated with 36 targets and 27 pathways in the treatment of DFU,of which the important components were luteolin,trans caryophyllene,ar-turmerone,palmitic acid,methyl palmitate,gallic acid,demethoxycurcumin,berberine,and rheic acid.The key targets were posttranscriptional silencing,topoisomerase II alpha,muscarinic acetylcholine receptor M2,interleukin 6,tumor necrosis factor and retinoic X receptor alpha,and the key pathways were the phosphoinositide 3-kinase-protein kinase B signaling pathway,neuroactive ligand–receptor interactions,and the forkhead box O signaling pathway.CONCLUSION Our results indicated that RHP may play a role in the treatment of DFU through these target pathways by affecting insulin resistance,altering the nervous system and immune system,participating in inflammatory responses and regulating cell proliferation,differentiation and apoptosis through other specific mechanisms.

Impact of Different Grinding Aids on Standard Deviation in X-Ray Fluorescence Analysis of Cement Raw Meal

X-ray fluorescence (XRF) analysis utilizes particle size which is resulted from milling of a material. The milling ensures uniform and fine grained powder. The finer and more uniform the particle size is, the better the result and easier it is for material quality control. To ensure uniformity in particle size and finer powder, a comparative analysis was conducted with different grinding aids and pressed pellet method was used in obtaining analysis results. Pressed pellets of cement raw meal sample milled with different grinding aids (graphite, aspirin and lithium borate) were subjected to XRF. Graphite produced better particle size uniformity with a corresponding standard deviation that made quality control of raw meal easier and better than aspirin and lithium borate.

Thermodynamic analysis on preparation of fibrous NiO precursor powders with oxalate precipitation process

According to the principles of simultaneous equilibrium and mass balance, a series of thermodynamic equilibrium equations of Ni（Ⅱ）-C2O2-4-NH3-NH+4-H2O system at ambient temperature are deduced theoretically and the logarithm concentration versus pH value（lg[Ni2+]T—pH） diagrams at different solution compositions are drawn. The results show that when pH is above 8.0, nickel ions coordinate with ammonia, the precipitation proceeds slowly accompanying with the release of nickel ions from the multi-coordinated Ni（NH3）2+n（n=1, 2, …, 6） and the morphology of NiO powder precursor is fibrous; when pH is below 8.0, nickel ion directly reacts with C2O2-4 and the morphology of NiO powder precursor is of cubic-shape. Some experiments were made to confirm the relation between the total concentration of nickel ion and pH. It is shown that the thermodynamic mathematical model is correct and the calculated values are basically accurate.

Characteristic Analysis of a Powder Quartz Mine in Yunnan Province

The characteristic study of powder quartz is the basis of the comprehensive utilization of quartz powder resources.In this paper,the characteristic of a powder quartz mine in Yunnan Province is analyzed, through the analysis of X-ray diffraction,chemical composition,SEM analysis of the different samples those purified to different extent,etc.The results indicated that the powder quartz’s whiteness is 81.4, and the main mineral compositions are quartz,clay mineral(mostly kaolinite and illite) and a little of feldspar,and the content of quartz is about 85%。

Application of methods of X-ray diffraction analysis and acoustic emission on research of plastic deformation in steels

Results of researches on plastic deformation of steels were obtained by acoustic emission and X-ray methods.The new numerical-analytical method of the thin structure parameter determination on one diffraction line was offered.It is supposed that with a growth of the deformation the cubic lattice will be transformed in the orthorhombic lattice.It is shown that changes of a condition of crystal structure of austenitic steel occur in four stages and of carbonaceous steel occur in six stages.Existence of two types of acoustic emission sources in carbonaceous steel and one type of acoustic emission source in austenitic steel was proposed.

AN INCREMENTAL METHOD OF X-RAY DIFFRACTION QUANTITATIVE PHASE ANALYSIS OF SAMPLESCONTAINING AMORPHOUS MATERIAL

A new method for quantitative X-ray diffraction phase analysis of a powder misture has been developed according to Popovic's doping method. The weight fraction of amorphous material in the analysed sample is obtained. For a multicomponent system in which (n-2) pure phases are added into an n-phase compnent sample and theweight fractions of all n phases can be determined by the method. The test results of confirmation agree well with the theory.