XRD Peak Intensity Research Articles

Complementary and Alternative Medicine: Impact of Consciousness Energy Healing Treatment on the Cholecalciferol (Vitamin D3)

Cholecalciferol is a steroid hormone (7-dehydroxycholesterol), which helps in the absorption of dietary minerals like zinc, calcium, magnesium, iron, and phosphate and also responsible for other biological activity. In this research study, the influence of the Trivedi Effect®-Consciousness Energy Healing Treatment on the physicochemical and thermal properties of cholecalciferol was evaluated using the modern analytical technique. The cholecalciferol test sample was divided into two parts. One of the test samples was considered as a control sample, which did not receive the Biofield Energy Treatment; whereas, the other part was treated with the Consciousness Energy Healing Treatment remotely by a well-known Biofield Energy Healer, Gopal Nayak and termed as a treated sample. The particle size values in the treated cholecalciferol powder sample were significantly decreased by 78.94% (d10), 26.21% (d50), 22.01% (d90), and 29.04% {D (4,3)}; thus, the specific surface area of the treated cholecalciferol was significantly increased by 174.12% compared to the control sample. The XRD peak intensities and crystallite sizes of the treated cholecalciferol powder sample were significantly altered ranging from -44.37% to 370.49% and -74.48% to 91.52%, respectively; therefore, the average crystallite size of the treated cholecalciferol was significantly decreased by 36.21% compared to the control cholecalciferol. The latent heat of fusion of the treated cholecalciferol was significantly increased by 25.89% compared to the control cholecalciferol. The weight loss was decreased by 1.48%; whereas, the residue amount was significantly increased by 107.02% in the treated sample compared with the control sample. Thus, the Trivedi Effect®-Consciousness Energy Healing Treatment generated a new polymorphic form of cholecalciferol which might offer better solubility, absorption, bioavailability, and be thermally more stable compared with the control sample. Henceforth, the Consciousness Energy Healing Treated cholecalciferol would be more beneficial to maintain the overall quality of life and it would be more useful in designing novel nutraceutical/pharmaceutical formulations for the better therapeutic responses against deficiency of vitamin D, osteoporosis, rickets, cardiovascular diseases, diabetes mellitus, cancer, mental disorders, multiple sclerosis, etc.

Impact of Consciousness Energy Healing Treatment on the Physicochemical and Thermal Properties of an Anticancer Drug 6-Mercaptopurine

Mercaptopurine is an antineoplastic chemotherapy drug is used for the treatment of cancer, Crohn's disease, ulcerative colitis, autoimmune diseases, etc. In this scientific study, the impact of the Trivedi Effect®-Consciousness Energy Healing Treatment on the physicochemical and thermal properties of 6-mercaptopurine was evaluated using the modern analytical technique. The test sample 6-Mercaptopurine powder was divided and named into control and treated sample. The control sample did not receive the Biofield Energy Treatment; whereas, the treated sample received the Biofield Energy Treatment remotely by a well-known Biofield Energy Healer, Gopal Nayak. The particle size values in the treated 6-mercaptopurine sample were significantly decreased by 10.18% (d10), 10.59% (d50), 7.62% (d90), and 9.17% {D(4,3)}; thus, the specific surface area was significantly increased by 10.28% compared to the control sample. The powder XRD peak intensities and crystallite sizes of the treated 6-mercaptopurine were significantly altered ranging from -43.40% to 23.33% and -37.09% to 136.67%, respectively; whereas the average crystallite size was significantly decreased by 11.04% compared with the control sample. The latent heat of evaporation and latent heat of fusion of the treated 6- mercaptopurine were significantly increased by 11.81% and 14.97% compared with the control sample. The total residue amount was significantly increased by 6.44% in the treated sample compared with the control sample. The maximum thermal degradation temperature of the 1st, 2nd, and 3rd peaks of the treated sample was altered by 1.55%, 0.18%, and -1.29% compared with the control sample. It was concluded that the Trivedi Effect®-Consciousness Energy Healing Treatment might have generated a new polymorphic form of 6-mercaptopurine which would offer better solubility, absorption, and bioavailability compared with the control sample. The Biofield Energy Treated 6-mercaptopurine would be more efficacious against acute lymphocytic leukemia, chronic myeloid leukemia, Crohn's disease, ulcerative colitis, and autoimmune diseases.

Optical simulation, characterization and thermal stability of Cr2O3/Cr/Cr2O3multilayer solar selective absorber coatings

Cr2O3/Cr/Cr2O3 multilayered selective solar absorber coating was deposited onto stainless steel substrates using electron beam vacuum evaporation at room temperature. The optical constants of the individual layers were obtained from reflectance measurements fitted by CODE software using the suitable dielectric function model, and showed that both Cr2O3 layers were dielectric in nature, while the Cr layer was semi-transparent due to its low thickness. Then, the experimental reflectance spectrum of the SS/Cr2O3/Cr/Cr2O3solar absorber was successfully simulated using CODE software. It was found that this coating exhibited a good spectral selectivity of 0.82/0.21 at 300 °C. The effect of annealing on the structural, morphological, mechanical and optical properties of the SS/Cr2O3/Cr/Cr2O3 solar absorber was investigated. SEM revealed an increase in Cr2O3 crystal size after annealing at 400 °C for 24 h in air, this leads to a surface smoothing illustrated by a decrease in roughness. The structural investigations of the annealed multilayered coatings showed a decrease in intensity of the stainless steel XRD peak linked to the increase in crystallinity of Cr2O3. Nanoindentation measurements showed that after annealing the samples were more resistant to mechanical solicitations as compared to as-deposited samples. Optical analysis showed that the sample annealed at 400 °C for 24 h exhibited higher absorptivity α = 0.89 and lower emissivity ε at 300 °C = 0.15than the as-deposited sample due to material structuring with temperature, which is promising for mid-to high temperature concentrated solar power applications in air. Coating optimization in CODE also indicated that α could be further improved to 0.916 without increasing emissivity.

Facile preparation of multi-doped TiO2/rGO cross-linked 3D aerogel (GaNF@TGA) nancomposite as an efficient visible-light activated catalyst for photocatalytic oxidation and detoxification of atrazine

The novel Ga, N, F co-doped TiO2@rGO aerogel (GaNF@TGA) nanocomposite was synthesized using a facile chemical method in the presence of ascorbic acid as a reducing agent and cross-linker. The XRD patterns indicated the lower intensity of the anatase XRD peak in doped-sample, which confirmed successful insertion of dopant atoms in the TiO2 lattice. FT-IR and Raman spectra confirmed the successful reduction of GO in the nanocomposite. The SEM and HRTEM images revealed the interconnected porous 3D network structure for the prepared TGA samples. Co-doping TiO2 with Ga, N and F caused considerable red shift in the absorption edge to the visible-light region. TGA catalyst had much higher photocatalytic activity than the plain TiO2 under visible-light irradiation due to the enhanced photogenerated charge separation for oxidation of atrazine (ATZ). The complete degradation of 40 mg/L ATZ was obtained in the photocatalytic oxidation process within 60 min with GaNF@TGA as catalyst. The reaction with OH at the surface of catalyst was the main mechanism contributed in degradation of ATZ in the developed photocatalytic process. The prepared catalyst showed a remarkable stability and simply separation for recycling. The cytotoxicity of fresh and photocatalytic-treated ATZ solutions assessed using the skin fibroblast cells (Hu02) indicated that treating ATZ solution in the developed visible-light photocatalytic reaction under optimum experimental conditions could considerably be detoxified. Accordingly, TGA is an efficient visible-light activated nanocomosite, which can be used as photocatalyts for enhanced degradation and detoxification of the emerging water contaminants.

Effects of precursor pH on structural and optical properties of CdTe quantum dots by wet chemical route

l-cysteine capped CdTe quantum dots (QDs) were synthesized in aqueous solution in open air. In order to improve the crystallinity of the CdTe QDs, synthesis conditions were optimized. Effects of different solution pH were investigated in order to determine the optimum pH for the growth of highly crystalline CdTe QDs. X-ray diffraction patterns (XRD) for all the as-prepared samples displayed a zinc blende crystal structure. The XRD peak intensities were found to increase to a certain pH level. This was accompanied by a general increase in the crystallite sizes (3.01–3.25 nm) of the CdTe QDs as the solution pH was gradually increased from 7 to 12.5. The calculated strain in the CdTe QDs was observed to decrease with an increase in the solution pH level. The morphological studies obtained from scanning electron microscope showed clear changes in the shape of CdTe QDs with various solution pH. The shape of the QDs changed from small spherical to large flower-like and needle-like structures for various solution pH. The optical spectroscopy studies revealed that the photoluminescence emissions were shifted to longer wavelength (545–593 nm) as the pH was increased from 7 to 12.5. The ultraviolet–visible analysis displayed a red shift in the absorption peaks with an increase in the pH levels. The optical band gaps obtained from the Tauc formula displayed an inverse relation with the solution pH which could be due to increase in the QDs’ sizes with increasing pH level.

Antimicrobial efficacy of green synthesized iron oxide nanoparticles

This paper reports experimental details for preparation of poly-dispersed hematite (Fe2O3) nanoparticles using Nyctanthes arbor tristis flower extract at physiological pH and room temperature. The bio-inspired fabricated iron oxide nanomaterial is characterized by XRD patterns which reveal the formation of a high crystalline quality with rhombohedral structure having hematite phase. It is observed that XRD peak intensity is affected by the concentration of precursor. The FT-IR analysis reveals the existence of Fe-O bonding in the synthesized nanoparticles. The FE-SEM analysis reveals the nanostructure which is found to be poly-dispersed bead like agglomerates. The synthesized nanoparticles exhibit potential antimicrobial efficacies against Kleb. pneumoniae and Staph. aureus. Also the minimum inhibitory concentrations of the synthesized nanoparticles have been determined.

Mechanical activation of pyrophyllite ore for aluminum extraction by acidic leaching

A pyrophyllite [Al2Si4O10(OH)2] ore as an alternative source for alumina (Al2O3) was intensively milled for mechanical activation to increase aluminum extraction by acid leaching method. For this purpose, unmilled and milled ore samples were compared to reveal the changes caused by intensive milling. The samples were also leached in HCl solutions to determine whether mechanical activation increased the alumina extraction or not. The milling considerably disrupted XRD peak intensities of the clay minerals found in the ore, except quartz. After milling just for 30 min, peaks of the minerals were not distinguished, suggesting that all are amorphous. Dehydroxylation of the minerals in the unmilled ore was realized to occur at lower temperature ranges and energy consumed for dehydroxylation significantly reduced with prolonged milling. While aluminum recovery by leaching of the unmilled ore was about 12%, it increased to 73.09% as a result of milling the ore for 50 min. It was concluded that as the milling time is extended, energy needed to undergo dehydroxylation due to amorphization continues to decrease and aluminum recovery reaches higher values, suggesting that the clay minerals in the ore can be converted to mechanically activated state.

Efficient Removal of Cadmium Using Edible Fungus and Its Quantitative Fluorimetric Estimation Using (Z)-2-(4H-1,2,4-Triazol-4-yl)iminomethylphenol.

Microbes accumulate heavy metals after adsorption or absorption. This study exhibited that Trametes versicolor can tolerate up to 5 mg/g concentration of cadmium. Change in fungus morphology due to cadmium along with its absorption were analyzed using SEM, XRD, and EDAX. Cadmium absorption usually increased with time, and it was determined quantitatively by a fluorimetry technique using a synthesized imine fluorophore as a specific probe and compared with results obtained from atomic absorption spectroscopy (AAS). The intensity of the cadmium-specific XRD peak gradually increased up to the seventh day, and the absorption by the organisms reduced the concentration of cadmium even from the effluent of the plating industry. After the seventh day, Trametes versicolor absorbed almost 0.300 mg/g concentration of cadmium as visualized under high content screening from the fluorescence appearance of hyphae. Hence it can be concluded that Trametes versicolor may play a key role in reducing cadmium from a contaminated environment.

Characterization of alloy 3033 after exposure to superheated steam at 800°C

Alloy 3033 was evaluated in superheated steam (SHS) at 800°C for a duration of 3000 hours. The SHS was able to simulate the supercritical water (SCW) condition at higher temperatures which no commercial SCW rig is currently capable of reaching. After exposure to the SHS, the weight change and surface oxide formation of Alloy 3033 were analyzed. Alloy 3033 had an initial weight gain after 1000 hours; however, the net weight gain reduced after 2000 and 3000 hours of exposure, suggesting oxide spallation. Formation of both Cr2O3 and MnCr2O4 was observed on the surface after 2000 and 3000 hours of SHS exposure. However, as exposure progressed, the XRD peak intensity ratio of MnCr2O4 to Cr2O3 decreased, in addition to the observation of more exposed Cr2O3. Based on this preliminary investigation, Alloy 3033 may not be suitable for extended use in SHS due to weight loss associated with oxide spallation.

First Principle and Experimental Study for Site Preferences of Formability Improved Alloying Elements in Mg Crystal

Some alloying elements (Al, Er, Gd, Li, Mn, Sn, Y, Zn) were proved recently by calculations or experiments to improve the formability of Mg alloys, but ignoring their site preference in Mg crystals during the calculated process. A crystallographic model was built via first principle calculations to predict the site preferences of these elements. Regularities between doping elements and site preferences were summarized. Meanwhile, in the basis of the crystallographic model, a series of formulas were deduced combining the diffraction law. It predicted that a crystal plane with abnormal XRD peak intensity of the Mg-based solid solutions, compared to that of the pure Mg, prefers to possess solute atoms. Thus, three single-phase solid solution alloys were then prepared through an original In-situ Solution Treatment, and their XRD patterns were compared. Finally, the experiment further described the site preferences of these solute atoms in Mg crystal, verifying the calculation results.

NOT‐INHIBIT Reversible Logic Gate Behavior of g‐C3N4‐Hg2+‐Complexed Nanoparticles

AbstractThe g‐C3N4‐Hg2+ complexed nanoparticles with two fluorescence emission (at 368 and 450 nm) have been synthesized and characterized with scanning electron microscope, transmittance electron microscope, Fourier‐transform infrared spectroscopy, ultraviolet‐ visible spectrophotometer and X‐ray diffraction methods. A decrease in the XRD peak intensity of g‐C3N4‐Hg2+ at 13.4° suggested that Hg2+ ions might be trapped into the in‐plane heptazine holes. Computational studies of g‐C3N4‐Hg2+ nanoparticles confirmed large binding energies for in‐plan‐Hg2+ structures and suggested that the fluorescence quenching (at 368 nm) is caused by the complexation of nanoparticles with Hg2+ ions. Due to the strong affinity between Hg2+ and CN− confirmed by computational studies, the quenched fluorescence emission at 368 nm “OFF” can be completely returned “ON” in the presence of CN− and then efficiently quenched by the addition of Hg2+. The OFF‐ON‐OFF fluorescence cycles have been exploited to design an “INHIBIT” logic gate using Hg2+ and CN− ions. In addition, the second emission peak (at 450 nm) was quenched by Cr2O72− and was not affected by other ions (Hg2+ and CN−) indicating a “NOT” (inverter) logic gate.

Electrical characteristics of dip coated TiO2 thin films with various withdrawal speeds for resistive switching applications

TiO2 thin films were coated on p-Si (100) substrate by sol gel dip coating method by varying the withdrawal speed from 1 cm/min to 4 cm/min. Post-deposition annealing of all the samples were carried out at 500 °C in air ambient. Uniform surface morphology has been observed for all the samples. The intensity of XRD peak corresponding to the anatase phase of TiO2 was found to be increased with the rise in withdrawal speed. The formation of titania was also confirmed by the FTIR study. Capacitance-voltage and current-voltage measurements were carried out by fabricating Al/TiO2/Si metal oxide semiconductor (MOS) structure. Oxide charge density (Qox) was calculated from the shift in flatband voltage and was found to be decreased with the increase in withdrawal speed. Interface trap density (Dit) was estimated to be 2.1 × 10−12 eV−1 cm−2 for withdrawal speed of 1 cm/min. The film deposited at the withdrawal speed of 1 cm/min has shown better bipolar resistive switching behavior with an enhanced resistive window in both the polarities.

Microstructure Evolution in Cast Al-Zn-Mg Alloys Processed by Equal Channel Angular Pressing

In the present work, microstructure development and enhancement in the microhardness of Al-Zn-Mg alloys (with 5, 10, and 15% zinc) during equal channel angular pressing (ECAP) were investigated. Dendritic morphology was observed in the cast condition of all three alloys, and precipitates were situated along the inter-dendritic regions. After homogenization, precipitates in the inter-dendritic regions were uniformly distributed in the aluminum matrix and grain boundaries were developed. After 4 passes in route BC, large reduction in the grain size was observed. X-ray diffractometry showed that MgZn2 precipitate was developed in the ECAP-processed samples. Increase in the intensity of MgZn2 peaks was observed when the quantity of zinc is increased in the material. Also, changes in the intensity of XRD peaks were observed in ECAP-processed samples due to shear deformation. After ECAP, substantial increase in the microhardness was perceived. After four passes, microhardness increased to 109, 67, and 58% from the initial condition in A1, A2, and A3 alloys, respectively. Also, improvement in the microhardness was also observed when the quantity of zinc is increased in the material.

Effect of doping on the properties and photocatalytic performance of titania thin films on glass substrates: Single-ion doping with Cobalt or Molybdenum

TiO2 thin films of varying Co and Mo individual doping levels (0.00–1.00 mol% metal basis) were fabricated on soda-lime-silica glass substrates by spin coating, followed by annealing at 450 °C for 2 h. Mineralogical analyses showed that all of the films were comprised only of anatase and suggested that both Co and Mo formed interstitial solid solutions. For the Co-doped films, the variation in anatase XRD peak intensities indicated three discrete stages of structural and nanostructural development: recrystallization (≤0.05 mol% Co), lattice distortion (0.05–0.60 mol% Co), and precipitation (≥0.60 mol% Co). For the Mo-doped films, Mo consistently enhanced nucleation, recrystallization, and lattice distortion within the solubility limit, which was not reached at 1.00 mol% Mo. Chemical analyses showed that Ti4+/Ti3+, Co3+/Co2+, and Mo5+/Mo4+ (and possibly Mo6+) were present in the films. The formation of non-equilibrium valences was considered in terms of the effects of crystal field stabilization energy (CFSE), intervalence charge transfer (IVCT), and electronegativity. Nanostructural analyses of the Co-doped films showed that, with increasing doping level, the grain size increased at the lowest level, followed by a decrease owing to changes in the structure (lattice destabilization) and nanostructure (localized liquid formation). In contrast, the grain size of the Mo-doped films increased with increasing doping level due to the maintenance of solid solubility, defect formation (and associated enhanced nucleation and recrystallization), and grain growth. Defect formation and charge compensation resulted in lattice contraction, which was confirmed by laser Raman microspectroscopy and resultant destabilization. Optical analyses showed that all of the thin films were flat, smooth, and nanostructurally homogeneous. The band gap data suggested that the governing effect derived from the lattice distortion associated with the lattice incorporation of both dopants. Photocatalytic testing showed that the lowest level of doping for both dopants (0.01 mol%) yielded maximal photocatalytic activity and that the performance decreased with increasing doping levels. This was attributed to the effects of nucleation and recrystallization, semiconducting effect, dopant size effect, and minimal lattice distortion.

Investigation of the Thermodynamic Properties of Surface Ceria and Ceria–Zirconia Solid Solution Films Prepared by Atomic Layer Deposition on Al2O3

The properties of 20 wt % CeO2 and 21 wt % Ce0.5Zr0.5O2 films, deposited onto a γ-Al2O3 by Atomic Layer Deposition (ALD), were compared to bulk Ce0.5Zr0.5O2 and γ-Al2O3-supported samples on which 20 wt % CeO2 or 21 wt % CeO2–ZrO2 were deposited by impregnation. Following calcination to 1073 K, the ALD-prepared catalysts showed much lower XRD peak intensities, implying that these samples existed as thin films, rather than larger crystallites. Following the addition of 1 wt % Pd to each of the supports, the ALD-prepared samples exhibited much higher rates for CO oxidation due to better interfacial contact between the Pd and ceria-containing phases. The redox properties of the ALD samples and bulk Ce0.5Zr0.5O2 were measured by determining the oxidation state of the ceria as a function of the H2:H2O ratio using flow titration and coulometric titration. The 20 wt % CeO2 ALD film exhibited similar thermodynamics to that measured previously for a sample prepared by impregnation. However, the sample with 21 wt % Ce0.5Zr0.5O2 on γ-Al2O3 reduced at a much higher P O 2 and showed evidence for transition between the Ce0.5Zr0.5O2 and Ce0.5Zr0.5O1.75 phases.

Effect of dual modification of HMT and crosslinking on physicochemical properties and digestibility of waxy maize starch

Waxy maize starch was subjected to crosslinking, HMT, crosslinking-HMT and HMT-crosslinking, and physicochemical properties and digestibility were examined. Crosslinked-HMT and HMT-crosslinked starch exhibited lower and higher phosphorus contents than crosslinked starch at the same concentrations of STMP/STPP (99:1, w/w), respectively. A low swelling power, a low paste clarity, a high melting temperature and a low ΔH were observed in crosslinked-HMT starch and HMT-crosslinked starch like crosslinked and/or HMT starch. Crosslinking-HMT and HMT-crosslinking mitigated the reduced XRD peak intensity observed for HMT. Crosslinked-HMT starch effectively produced RS, showing 28.7–41.5% RS in raw starch and 23.3–25.0% in gelatinized starch. The RS proportion of crosslinking-HMT was similar to that of crosslinking in raw starch, but HMT and crosslinking-HMT showed similar RS proportions in gelatinized starch. Crosslinking-HMT advantageously produced RS from both crosslinking and HMT; however, this was not observed in HMT-crosslinking.

Preparation and characterization of ZnS nanoparticles prepared by hydrothermal method

ZnS nanoparticles were prepared by hydrothermal method using zinc nitrate [Zn(NO[Formula: see text] ⋅ 6H2O] and thiourea [SC(NH[Formula: see text]] as sources of Zn[Formula: see text] and S[Formula: see text] ions and cetyltrimethyl ammonium bromide [CH3(CH2)[Formula: see text]N[Formula: see text](CH3)3 ⋅ Br[Formula: see text]; CTAB] as a surface active agent. The structural, surface morphology and optical properties of ZnS nanoparticles as a function of growth temperature were investigated. The studies show that ZnS nanoparticles have high transmittance over 70% in the visible light range of 400–800 nm, and it has a strong green emission band at about 520 nm which originates from the recombination of electrons from the energy level of sulfur vacancies with the holes from the energy level of zinc vacancies. With the increase of the growth temperature, the XRD peak intensity and the size of ZnS nanoparticles increase, while the green emission intensity firstly increases and then decreases.

Effect of lanthanum addition on the fabrication of REBa2Cu3Oy (RE=Gd, Sm and Dy) thin films by metal organic deposition using fluorine-free solutions

The effects of lanthanum (La) additions of 0.5–10 mol% on the superconducting properties and crystal growth of REBa2Cu3Oy (REBCO, RE = Gd, Sm, and Dy) films fabricated by the fluorine-free metal-organic deposition method using 2-ethylhexanate solutions were investigated. La-doped REBCO films showed the decrease in the number density of holes on the film surface and the increase in the XRD peak intensity of the REBCO superconducting phases. La-added GdBCO with La contents of 0.5–3 mol%, and SmBCO and DyBCO films with La contents of 0.5–10 mol% showed improved critical current density (Jc) at the self-magnetic field compared to the pure films. For the GdBCO film, the Jc value at the self-magnetic field increased from 1.32 to 2.38 MA/cm2 upon La addition.

The effect of hydrothermal impregnation of Ni, Co, and Cu on HZSM-5 in the nitrogen oxide removal

The selective catalytic reduction (SCR) of nitrogen oxides on M/ZSM-5 (M = Cu, Ni, Co) catalysts was investigated. The catalysts were prepared using hydrothermal impregnation of the metal chlorides and nitrates on ZSM-5. The catalysts were characterized by nitrogen absorption/desorption, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible diffusion reflection spectroscopy (UV–Vis DRS), temperature-programmed reduction (TPR), N2O chemisorption and ammonia temperature-programmed desorption. The performance tests for SCR of NO were carried out in a fixed-bed reactor from 250 to 400 °C. During the impregnation, part of the aluminum was eliminated from the zeolite framework due to the acidity of the metal salt solution and heating process as indicated by the reduction in the intensity of XRD peaks and variations in the positions of the FTIR vibrational bands. The Cu(Cl)/ZSM-5 catalyst exhibited NO conversions over 90% over the entire temperature range. The other catalysts showed comparable activities, but the catalysts prepared with chloride salt precursors demonstrated higher activity than those based on nitrate as the precursor. Moreover, the TPR reduction peaks of the metal ion in catalysts prepared with chloride precursor were lower, and their UV–Vis absorption bands revealed bathochromic transfers with higher intensities. Concurrent with these changes, the activity of the catalyst increased. The TPR profiles indicated that Cu and Ni both had an oxidation number of +2, whereas Co was present in the oxidation number of +2 and +3. The mass transfer limitation analysis showed that for particles in millimeter size range or larger significant intra-particle mass transfer limitation would be expected.

분무열분해 공정에 의한 평균입도 50 nm 이하의 코발트 산화물 분체 제조에 미치는 공기압력의 영향

본 연구에서는 코발트 염화물(<TEX>$CoCl_2$</TEX>) 용액을 원료로 하여 분무열분해 반응에 의하여 평균입도 50 nm 이하의 코발트 산화물(<TEX>$Co_3O_4$</TEX>) 분말을 제조하였으며 분위기 기체인 공기의 압력 변화에 따른 입자들의 특성 변화를 파악하였다. 공기압력이 <TEX>$0.1kg/cm^2$</TEX>인 경우에는 형성된 액적형태들은 구형이 거의 없었으며 매우 심하게 분열된 상태를 나타내고 있었다. 액적형태를 구성하는 나노 입자들의 평균입도는 약 40 nm이었다. 공기압력이 <TEX>$0.5kg/cm^2$</TEX>으로 증가된 경우에는 액적형태를 구성하는 나노 입자들의 평균입도는 약 35 nm로 감소되었다. 공기압력이 <TEX>$3kg/cm^2$</TEX>으로 증가된 경우에는 액적형태에서 구형의 비율이 현저하게 증가하였고 분열된 정도는 감소하였으며 나노 입자들의 평균입도는 약 30 nm로 감소하였다. 공기압력이 <TEX>$0.1kg/cm^2$</TEX>로부터 <TEX>$1kg/cm^2$</TEX>로 증가하는 경우에는 XRD 피크들의 강도가 거의 변화가 없는 반면 비표면적은 감소함을 나타내었다. 공기압력이 <TEX>$3kg/cm^2$</TEX>로 증가하는 경우에는 XRD 피크들의 강도는 약간 감소하는 반면 비표면적은 증가하고 있었다. When the ambient air pressure was <TEX>$0.1kg/cm^2$</TEX>, there were few spherically formed droplets, which showed very badly fragmented state. The average particle size of the particles constituting the droplet was about 40 nm. When the air pressure increased to <TEX>$0.5kg/cm^2$</TEX>, the ratio of the spherical droplet forms increased, but still showed a state of severe disruption. The average particle size of the particles was reduced to about 35 nm. As the air pressure increased to <TEX>$3kg/cm^2$</TEX>, the ratio of spherical droplet form significantly increased, the degree of fragmentation even further decreased and the average particle size decreased to 30 nm. When the air pressure increased from 0.1 to <TEX>$1kg/cm^2$</TEX>, the XRD peak intensity showed little change, but the specific surface area was decreased. As the air pressure increased to <TEX>$3kg/cm^2$</TEX>, the intensity of XRD peaks showed a little decrease, while the specific surface area increased.