scholarly journals The Fine Characterization and Potential Photocatalytic Effect of Semiconducting Metal Minerals in Danxia Landforms

Minerals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 554
Author(s):  
Yuxiong Xiao ◽  
Yanzhang Li ◽  
Hongrui Ding ◽  
Yan Li ◽  
Anhuai Lu
Keyword(s):  
Electron Microscopy ◽  
Environmental Effects ◽  
Spatial Relationship ◽  
Environmental Scanning Electron Microscopy ◽  
Optical Microscope ◽  
Element Distribution ◽  
Hunan Province ◽  
Red Beds ◽  
X Ray ◽  
Danxia Landform

The Danxia landform is representative of the Cretaceous continental red sediment. The careful identification and potential environmental effects of minerals in Danxia red beds have yet to be clearly reported. In this work, reddish sandstone samples were collected from Lang Mountain Danxia landform in Xinning, Hunan province, China, and their mineral phases, element distribution, microstructure, and the spatial relationship of different minerals were investigated using polarizing optical microscope, environmental scanning electron microscopy, energy-dispersive X-ray analysis, electron probe microanalysis, micro-Raman spectra, micro- X-ray diffraction, X-ray fluorescence spectroscopy, and high-resolution transmission electron microscopy. The results revealed that iron oxide (mainly hematite) and titanium oxide (mainly anatase) were the dominant minerals in Danxia red layers. Microcrystalline hematite was suggested as being the coloring mineral. Anatase, reported here for the first time in Danxia red beds, constituted the content of titanium in the red layer (0.17–0.57%) and was present in a significantly higher amount than the adjacent limestone formation (0.13%). Over 95% of Fe/Ti oxides served as a cementation agent along the framework of coarse-grain minerals (quartz and feldspar). The hematite and anatase were visible-light-responsive semiconductors, with a band gap of 2.01 eV and 3.05 eV, respectively. Photoelectrochemical experiments were performed on synthetic hematite, anatase, and their coupled material. The inactive hematite displayed an enhanced 23-fold photocurrent at 0.8 V (vs. Ag/AgCl) when coupled with anatase. Furthermore, in a photodegradation experiment using methyl orange dye under simulated sunlight, the coupled material showed decolorizing efficiency 2.4 times that of hematite. The anatase, therefore, prominently improved the photocatalytic activities of hematite. It is proposed that these semiconducting minerals in red beds produce oxygen reactive species and have significant environmental effects, which is of great importance.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

scholarly journals Characterization of a Mahamayuri Vidyarajni Sutra excavated in Lu’an, China

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Liu Liu ◽  
Decai Gong ◽  
Zhengquan Yao ◽  
Liangjie Xu ◽  
Zhanyun Zhu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tang Dynasty ◽  
Optical Microscope ◽  
Lead White ◽  
Scientific Methods ◽  
X Ray ◽  
Micro Raman Spectroscopy ◽  
Scanning Electron

Abstract Historically, sutras played an important role in spreading Buddhist faith and doctrine, and today these remain important records of Buddhist thought and culture. A Mahamayuri Vidyarajni Sutra with polychrome paintings was found inside the cavity on top of the Nanmen Buddhist pagoda, built in the early Tang dynasty (618–627 CE) and located in Anhui Province, China. Textile was found on the preface which is strongly degraded and fragile. Unfortunately, the whole sutra is under severe degradation and is incomplete. Technical analysis based on scientific methods will benefits the conservation of the sutra. Optical microscopy (OM), micro-Raman spectroscopy combined with optical microscope (Raman), scanning electron microscopy in combination with energy dispersive X-ray analysis (SEM–EDS) and Fourier Transform Infrared Spectroscopy (FTIR) were used to characterize the pigment and gilded material, as well as the paper fiber and textile. Pigments such as cinnabar, minium, paratacamite, azurite, lead white were found. Gilded material was identified as gold. A five-heddle warp satin, made of silk, was found as the textile on the preface of the sutra. The sutra’s preface and inner pages were made of paper comprised of bamboo and bark. As a magnificent yet recondite treasure of Buddhism, the sutra was analyzed for a better understanding of the material. A conservation project of the sutra will be scheduled accordingly.

A Simple Method for Controlling the Morphology of CuO Nanostructures by Droplet

2012 ◽  
Vol 535-537 ◽  
pp. 280-283 ◽  
Author(s):  
Hao Ran An ◽  
Feng Shi Cai ◽  
Xue Wei Wang ◽  
Zhi Hao Yuan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscope ◽  
Growth Mechanisms ◽  
X Ray Diffraction ◽  
Simple Method ◽  
Hydrophobic Substrate ◽  
X Ray ◽  
Shape Selective ◽  
Scanning Electron

Different morphology CuO nanostructures, including platelets, flower-like were simply synthesized at 350 °C controlled by droplet on hydrophobic substrate. This is a simple method which does not require any template, catalyst, or surfactant but can control the morphology of CuO from platelets to flowerlike. The morphologies are strongly dependent on the volume of droplet. Scanning electron microscopy (SEM), Optical microscope and X-ray diffraction (XRD) were used to observe the morphology, crystallinity, and chemical composition of the CuO structures. Growth mechanisms for shape selective CuO synthesis were proposed based on these results.

Applications of Environmental Scanning Electron Microscopy in Art Conservation and Archaeology

1990 ◽  
Vol 185 ◽  
Author(s):  
Dusan Stulik ◽  
Eric Doehne
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Micrographs ◽  
New Technology ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Art Conservation ◽  
Pilot Studies ◽  
X Ray ◽  
Scanning Electron

AbstractThe principles of Environmental Scanning Electron Microscopy (E-SEM) are explained and discussed. The performance of the E-SEM compares favorably with the performance of traditional SEM instruments. This new technology has significant advantages in art conservation and archaeology. In this paper we describe several pilot studies which explored potential uses of the E-SEM. Electron micrographs recorded from moist, outgassing, and difficult to coat samples are presented, together with X-ray spectra recorded from uncoated samples of electrically nonconductive materials.

scholarly journals Multi-scale characterization of glaucophane from Chiavolino (Biella, Italy): implications for international regulations on elongate mineral particles

2021 ◽  
Vol 33 (1) ◽  
pp. 77-112
Author(s):  
Ruggero Vigliaturo ◽  
Sabrina M. Elkassas ◽  
Giancarlo Della Ventura ◽  
Günther J. Redhammer ◽  
Francisco Ruiz-Zepeda ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Atomic Scale ◽  
Energy Dispersive ◽  
Mineral Particle ◽  
X Ray ◽  
Mineral Particles ◽  
Particle Population ◽  
Investigation Methods

Abstract. In this paper, we present the results of a multi-analytical characterization of a glaucophane sample collected in the Piedmont region of northwestern Italy. Investigation methods included optical microscopy, powder X-ray diffraction, Fourier-transform infrared spectroscopy, µ-Raman spectroscopy, Mössbauer spectroscopy, electron probe microanalysis, environmental scanning electron microscopy and energy-dispersive X-ray spectroscopy, and scanning/transmission electron microscopy combined with energy-dispersive X-ray spectroscopy and electron energy-loss spectroscopy. In addition to the crystal–chemical characterization of the sample from the mesoscale to the near-atomic scale, we have also conducted an extended study on the morphology and dimensions of the mineral particles. The main finding is that studying the same particle population at different magnifications yields different results for mineral habit, dimensions, and dimensional distributions. As glaucophane may occur as an elongate mineral particle (e.g., asbestiform glaucophane occurrences in California and Nevada), the observed discrepancies therefore need to be considered when assessing potential breathability of such particles, with implications for future regulations on elongate mineral particles. While the sample preparation and particle counting methods are not directly investigated in this work, our findings suggest that different magnifications should be used when characterizing an elongate mineral particle population, irrespective of whether or not it contains asbestiform material. These results further reveal the need for developing improved regulation for elongate mineral particles. We thus propose a simple methodology to merge the datasets collected at different magnifications to provide a more complete description and a better risk evaluation of the studied particle population.

NMR, crystallography, and electron microscopy of nucleoprotein complexes

1996 ◽  
Vol 54 ◽  
pp. 46-47
Author(s):  
F. P. Ottensmeyer
Keyword(s):  
Electron Microscopy ◽  
Nmr Spectroscopy ◽  
Spatial Relationship ◽  
X Ray ◽  
X Ray Crystallography ◽  
Tissue Sections ◽  
Nucleoprotein Complexes ◽  
Nmr Crystallography ◽  
The Relationship ◽  
Major Emphasis

The forte of electron microscopy in biology is its unique ability to elucidate the very diverse structures of biological specimens at a range of sizes, with relationships within tissue sections, between and within cells, subcellular organelles, and macromolecules, for the latter with increasingly finer detail. It is the relationship between molecules that is the essence of biology, and it is here that a major emphasis in effort has been placed in recent years in terms of structure determination, not only in electron microscopy, but also in fields with complementary structural approaches, such as the classical x-ray crystallography and the much more recent NMR spectroscopy. The spatial relationship between nucleic acids and proteins is only one facet of this effort, albeit a most important one.Conventionally electron microscopy has a spatial resolution of about 20 Å in stained biological specimens, but has succeeded with near-atomic resolutions in several cases. NMR spectroscopy per force has to start at atomic dimensions, since its inter-nuclear signals are only available at short range. It builds outward mathematically to molecular dimensions. In the process the technique has permitted the elucidation of detailed interactions, not only between atoms on the same molecule, but in a number of instances between atoms of interacting macromolecules.

Electron Microscopy and X-Ray Microanalysis in Forensic Science

1973 ◽  
Vol 56 (4) ◽  
pp. 930-943
Author(s):  
John L Brown ◽  
James W Johnson
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Chemical Elements ◽  
Optical Microscope ◽  
Forensic Analysis ◽  
Depth Of Focus ◽  
Crystalline Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Abstract The optical microscope has long been an important tool in forensic analysis for the comparison of firearms markings and the examination and identification of other minute bits of evidence. The electron microscope permits the examination of even smaller details and offers analytical capabilities unique to the type of instrument used. The transmission electron microscope can be used to identify very small amounts of crystalline materials through the process of electron diffraction. The scanning electron microscope can frequently supersede the optical microscope because of its superior depth of focus and range of magnification. When it is equipped with an energy dispersive X-ray analyzer, most of the chemical elements in a sample can be determined. Applications of these instruments have provided some interesting and instructive results in forensic analysis.

EFFECT OF Cr3C2 ADDITION ON THE MICROSTRUCTURE AND PROPERTIES OF LASER CLADDING NiCrBSi COATINGS

2019 ◽  
Vol 26 (06) ◽  
pp. 1850207 ◽  
Author(s):  
XUELONG PING ◽  
SHUTING SUN ◽  
FENG WANG ◽  
HANGUANG FU ◽  
JIAN LIN ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Wear Resistance ◽  
Laser Cladding ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nicrbsi Coatings ◽  
Scanning Electron ◽  
Microhardness Tester

In this paper, the enhancement of NiCrBSi coatings by adding Cr3C2 were investigated. The NiCrBSi coatings with different additions of Cr3C2 were produced by laser cladding. The microstructure, hardness and wear resistance of the coatings were studied by optical microscope (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), microhardness tester and M-200 wear tester. It is found that the main phases in the coatings are [Formula: see text]-Ni, Cr[Formula: see text]C6 and Cr7C3, and they also contain a small amount of CrB, Ni4B3 and Ni3Si2. Moreover, with the increase of Cr3C2 addition, the microhardness and wear resistance of coatings are obviously improved. When the addition of Cr3C2 is 20%, the wear resistance of the coating is the best, and the wear resistance of the coating increased by 191.2% than that of the Cr3C2-free coating. The wear resistance of coating decreases when the addition of Cr3C2 reaches 30%.

scholarly journals Influence of phase distribution of converter slag microzones on the occurrence of P

2021 ◽  
Vol 40 (1) ◽  
pp. 40-44
Author(s):  
Chenxiao Li ◽  
Shuai Tong ◽  
Yuekai Xue ◽  
Shuhuan Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Energy Spectrum ◽  
Activity Coefficient ◽  
Phase Distribution ◽  
Converter Slag ◽  
Element Distribution ◽  
X Ray ◽  
Backscattered Electron ◽  
Scanning Electron

Abstract The phase and element distribution of converter slag was analyzed with the backscattered electron (BSE) images of scanning electron microscopy and X-ray energy spectrum. The results show that the Ca and Si are attached in the slag micro-area, while the Fe is present in areas with less Ca and Si. Most of the P appear in areas with more Ca and Si. The content of SiO2 tends to increase with an increase in the CaO content in the slag micro-area. The activity of a CaO increases with an increase in the CaO content in the slag micro-area, while the activity of a FeO increases first and then decreases. In the slag micro-area with an increase in the FeO content, both the mole fraction and the activity coefficient of SiO2 decrease; so, the content of SiO2 decreases gradually.

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