Sh. Chadraabal

Nanocrystalline ZnO powder prepared by high energy ball mill

We have obtained zinc oxide (ZnO) in the form of nanocrystallites with crystallite sizes from 46 nm to 3 nm by milling 1.4 micron ZnO powders in the high energy ball mill (HEBM) for the different times: 1, 5 and 8 hours. Crystal structure changes of the ZnO nanocrystallites were studied by x-ray diffraction techniquies. It was established appearance of two new phases: pure zinc (Zn) and cubic zinc oxide (ZnO) among the initial hexagonal zinc oxide phase. From the x-ray patterns by using Scherrer equation have been determined nanocrystallite sizes of samples with the different milling times. Also, by using PCCS with Nanophox we have found particle diameters, their distributions and specific surface area values for each sample. By using Rietveld method are calculated crystal lattice parameters of the hexagonal ZnO, the main phase.

To the problem of development of the green technology for obtaining the high activity CaO oxides

We have carried out experimental investigations of obtaining high activity CaO oxides from the CaCO3-C systems where as a source of the carbon can serve pure graphite and remnant or incompletely burned coals in Thermal power plants ashes. It is shown that the process occurs by self-enhanced thermally chemical reactions and does not require additional energy.

A study of nanoparticle sizes and their distributions aerosols along the road in Ulaanbaatar city

Particle sizes and their distributions of aerosols along the road in Ulaanbaatar city were studied by Photon Cross Correlation Spectroscopy (PCCS) NANOPHOX (Sympatec GmbH, Germany). Mean diameter (x₀), size distribution range, specific surface area (Sv) of aerosol particles are equal to 1.1÷2.5μm, 74nm÷4.0μm and 2.38÷5.43m²/cm³ respectively. On the other hand, particles distribution is Gaussian with density 0.02÷8.15 (q₃lg) in the range of 790nm÷3.8μm. However, nanoparticles with diameters less than 74nm were not observed. The results reveal that samples contain 0.02% (volume persent) ultrafine particles or nanoparticles occur in the range of 74-100nm, 83.73% fine particles (PM2.5) occur in the range of 100nm÷2.4μm and 16.25% coarse particles (PM10) occur in the range of 2.4-4.0μm. It can be concluded that road aerosol sample contain high percent of PM2.5 particles.

A study of crystal structure and particle size of perovskite type La 1−x Cu x MnO 3+δ (x≤0.1) compounds suspended in water

Nanosized La_1-xCu_xMnO₃ (x≤0.1) was synthesized at different temperatures by using heteronuclear complexing method. X-ray diffraction analysis show that sample consists of two phases: La_1-xCu_xMnO₃ (x≤0.1) having R3̅c space group with rhombohedral symmetrical structure and La₂Cu₂O₅ having C2/c space group with monoclinic symmetrical structure. The results show the quantity of La_1-xCu_xMnO₃ increase from 91.22 to 97.62%, while quantity of La₂Cu₂O₅ compound decrease from 8.78 to 2.37% with rising of calcination temperature from 500°C to 900°C. The Photon Cross Correlation Spectroscopy (PCCS) was used to measure size distribution. The results reveal that particle mean diameter increases from (276±4) to (455±5)nm, particle specific surface area (Sv) decreases from 21.84 to 13.29 m²/cm³, particle size distribution equals to 55-761nm and particle surface and volume mean diameter (SMD, VMD) increase from 247 to 459nm.

TOF neutron scattering investigations of crystal structures in K 1−x (NH 4 ) x Cl (x=0.2, 0.8) mixed crystals

TOF neutron diffraction study shows that at the room temperature K<inf>0.2</inf>(NH<inf>4</inf>)<inf>0.8</inf>Cl and K<inf>0.8</inf>(NH<inf>4</inf>)<inf>0.2</inf>Cl compounds form cubic crystal lattices with the corresponding space groups: Fm3m and Pm3m. It was established considerable distortion of hydrogen atoms in these structures from their initial positions 8g.

X-ray diffraction studies of crystal structures and phase transitions in K 1−x (NH4) x Cl mixed salts

Crystal structures and phase transitions of K<inf>1−x</inf> (NH<inf>4</inf>)<inf>x</inf>Cl mixed salts with non-stoichiometric composition x=0.1, 0.2, 0.5, 0.6 and 0.8 have been studied by x-ray diffraction technique. It was established that at the room temperature K<inf>0.8</inf>(NH<inf>4</inf>)<inf>0.2</inf>Cl and K<inf>0.9</inf>(NH<inf>4</inf>)<inf>0.1</inf>Cl compounds have Fm3̅m symmetry and K<inf>0.2</inf>(NH<inf>4</inf>)<inf>0.8</inf>Cl compound has Pm3m, when K<inf>0.5</inf>(NH<inf>4</inf>)<inf>0.5</inf>Cl and K<inf>0.4</inf>(NH<inf>4</inf>)<inf>0.6</inf>Cl compounds consist of two phases with space groups Fm3̅m + Pm3m. Lattice parameters, positions and thermal factors of K, N and CI atoms have been refined using x-ray diffraction study for each mixed crystals.

Crystal structural investigations of Mongolian natural zeolites

We have studied zeolitic rocks discovered in Mongolia using electron microscopy (SEM), X-ray fluorescence (XRF), X-ray diffraction (XRD) methods. SEM, XRF and XRD measurements were carried out in the Max Plank Institute of Stuttgart, Germany. Our samples are collected from Mongolian deposits: Tsagaan tsav, Tushig uul, Urgun deposit, Bayan Zurkh Black Mountain and Mandal ovoo. Firstly, we have made chemical element analysis by using X-ray fluorescence spectroscopy which gives chemical contents of samples from all zeolite deposits. Comparing contents of above 5 deposits samples shows us that zeolite of Tushig Mountain, Dornogobi, is has the highest content of potassium and can be identified in potassium clinoptilolite- K (2.56 at %), others belong to clinoptilolite- Na. The main cations are K,Na,Ca,Mg,Fe,Ti for all the samples from the above mentioned deposits. Also, the (Si Al)/O ratio shows that the Mongolian zeolites have comparatively good qualities. We made X-ray phase analysis study on X-ray powder diffractometer Bruker-Axes D8 and refined the X-ray diffraction spectra by using ≪Match! Crystal Impact≫ program. As a result, we established that these zeolites are Na and K type of clinoptilolite with monoclinic symmetry (C2/m). Finally, the exact crystallochemical formula of clinoptilolites can be written as the next: • (Na<inf>2.02</inf>, K<inf>1.81</inf>, Mg<inf>0.49</inf>, Ca<inf>0.46</inf>, Fe<inf>0.36</inf>)(Al<inf>6.28</inf>O<inf>30.45</inf>) (Si<inf>28.47</inf>O<inf>30.45</inf>)·z·H<inf>2</inf>O for Tsagaan tsav sample. • (K<inf>2.56</inf>, Na<inf>1.69</inf>, Mg<inf>0.64</inf>, Ca<inf>0.47</inf>, Fe<inf>0.78</inf>)(Al<inf>6.39</inf>O<inf>28.15</inf>) (Si<inf>31.17</inf>O<inf>28.15</inf>)·z·H<inf>2</inf>O for Tushig Mountain sample. • (Na<inf>2.34</inf>, K<inf>1.48</inf>, Mg<inf>0.86</inf>, Ca<inf>0.57</inf>, Fe<inf>0.62</inf>)(Al<inf>7</inf>O<inf>29.03</inf>) (Si<inf>29.07</inf>O<inf>29.03</inf>)·z·H<inf>2</inf>O for Urgun deposit sample. • (Na<inf>2.14</inf>, K<inf>1.64</inf>, Mg<inf>0.53</inf>, Fe<inf>0.64</inf>, Ti<inf>0.19</inf>)(Al<inf>6.38</inf>O<inf>28.95</inf>) (Si<inf>30.59</inf>O<inf>28.95</inf>)·z·H<inf>2</inf>O for Bayan Zurh Black Mountain sample. • (Na<inf>3.59</inf>, K<inf>1.17</inf>, Ca<inf>1.17</inf>, Mg<inf>0.68</inf>, Fe<inf>0.30</inf>)(Al<inf>6.58</inf>O<inf>28.90</inf>) (Si<inf>28.65</inf>O<inf>28.90</inf>)·z·H<inf>2</inf>O for Mandalovoo sample.

Crystal structure of Mongolian phosphorite minerals and mechanochemistry

We have carried out crystal structure investigations of natural and mechanochemically activated samples of Burenkhan, Tsakhir uul and Aldarkhan phosphorite deposits (The Nord Mongolia) by X-ray, neutron and synchrotron powder diffraction techniquies.

Rietveld refinement of nanostructural LaMnO 3+δ perovskite-type manganite

The nanostructural LaMnO3+δ perovskite manganite investigated by x-ray diffraction (XRD). Our sample have been synthesized by the amorphous heteronuclear complexing method at 800°C temperature. X-ray diffraction analysis using Rietveld refinement show that our sample is single phase and crystallize in the rhombohedral distorted perovskite structure with R3̅c space group and with lattice parameters of a = b = 0.550 and c =1.334nm. It was established considerable distortion of oxygen atom in the rhombohedral structure from own initial positions 4b. Our results indicate that oxygen excess parameter for LaMnO3+δ is 0.29. We determined the crystallite size 39 – 47 nm of LaMnO3+δ using Scherrer equation from x-ray diffraction pattern.

The x-ray structure and osteostereometric study the sponge bone of Mongols

An X-ray diffraction study of crystal structure of bone apatite of Mongols and its changes and dependence on human ages has been carried out. The FullProt program based on the Rietveld method was used. In apart from separating proteins molecule off each sample was heated at 800°C during 30 minutes. Not depending on this heat treatment of all the samples consist only the fluoric apatite (Ca5(PO4)F) phase. As a result of refinement of the diffractograms it was established variation of parameters of bone apatite crystal structures (the unite cell constants, the coordinates of atoms, Debye-Waller heat factors of atoms, the atom contents and the unite cell volume) on different ways. It is also evident that the Ca1 atomic content increases with aging.