scholarly journals Optical spectroscopic study of Ru and Rh doped Bi12TiO20 crystals

2019 ◽  
Vol 51 (2) ◽  
pp. 219-223
Author(s):  
P. M. Rafailov ◽  
R. Todorov ◽  
V. Marinova ◽  
D. Z. Dimitrov ◽  
M. M. Gospodinov
Keyword(s):  
Near Infrared ◽  
Infrared Region ◽  
Visible Spectral Range ◽  
Oxidation States ◽  
Vibrational Modes ◽  
Spatially Resolved ◽  
Stretching Vibration ◽  
Growth Method ◽  
Polarized Raman ◽  
Top Seeded Solution Growth

Bi12TiO20 (BTO) single crystals in pristine state and doped with ruthenium and rhodium are grown by the top-seeded solution growth method and characterized by optical and Raman spectroscopy. The effect of doping on the vibrational and optical properties is studied. The doped crystals show higher absorption in the visible spectral range and higher transmission in the near infrared region as compared to pristine BTO. The performed spatially resolved polarized Raman measurements reveal no significant doping-induced shift of vibrational modes while differences in the LO/TO intensity ratio of the tetrahedral asymmetric stretching vibration are encountered. The observations are discussed in terms of lattice ordering and dopant oxidation states.

scholarly journals Computed Tomography Imaging Agent Based on Gold Nanoparticles for Internal Iliac Artery Embolization after Endovascular Abdominal Aortic Repair and CCN3 Protection Mechanism

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Siying Pei ◽  
Yao Sun ◽  
Dongxu Fan ◽  
Shuhua Deng ◽  
Haoran Mei ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Near Infrared ◽  
Infrared Region ◽  
Fluorescent Properties ◽  
Protection Mechanism ◽  
Abdominal Aortic ◽  
Infrared Rays ◽  
Growth Method ◽  
Internal Iliac ◽  
Endovascular Abdominal Aortic Repair

Abdominal aortic aneurysm is more stressful and has more complications in many diseases. During treatment and repair, arteriosclerosis, abdominal congestion deposition, and abdominal swelling cannot be eliminated. In this paper, we used the seed growth method to obtain gold nanoparticles (AuNPs) with good morphology and dispersion. The AuNPs of larger aspect ratio synthesized in this experiment moved their longitudinal plasmon resonance absorption peak to the near-infrared region, which provided suitable materials for subsequent experiments and laid the foundation for the photothermal therapy of tumors. Experiments show that near-infrared rays can penetrate into deep tissues to overcome the shortcomings that visible light cannot penetrate abdominal aorta well. AuNPs absorb near-infrared rays, thereby generating heat energy to achieve the purpose of treating tumors. In addition, AuNPs also have fluorescent properties, combined with other forms of imaging methods, to achieve the purpose of multimodal imaging, and improve the diagnostic accuracy of studying the protection mechanism of the nephroblastoma overexpressed (NOV or CCN3) gene.

Darstellung und spektroskopische Charakterisierung von Hexachloroosmat(V) / Preparation and Spectroscopical Characterisation of Hexachloroosmate(V)

1983 ◽  
Vol 38 (6) ◽  
pp. 680-686 ◽  
Author(s):  
W. Preetz ◽  
M. Bruns
Keyword(s):  
Near Infrared ◽  
Bathochromic Shift ◽  
Point Group ◽  
Visible Region ◽  
Infrared Region ◽  
Vibrational Modes ◽  
Resonance Raman Spectrum ◽  
Standard Potential ◽  
Charge Transfer Transitions ◽  
Near Infrared Region

Abstract (TEA)[OSCl6] is formed quantitatively by heating solid trans-(TEA)[OsX4(CO)2] (X = Br, I) in a stream of chlorine at 120 °C, and can be purified by recrystallisation from CH2Cl2 without decomposition. It is reduced immediately by acetone, methanol, Cl-, Br-, I- to give [OsCl6]2-. The standard potential [OsCl6]-/[OsCl6]2- in acetonitrile referred to the saturated mercury-mercurous sulphate electrode is 0.840 V. The IR and Ra bands of (TEA)[OsCl6], assigned according to point group Oh, are shifted to higher frequencies compared with (TEA)2[OsCl6]. The excitation at 488.0 nm gives a resonance Raman spectrum exhibiting 6 overtones of vi and combination tones up to 4ν1 + v5. The electronic absorption spectrum shows five spin-forbidden intraconfigurational transitions coupled with odd vibrational modes in the near infrared region. The spin-allowed 4A2g → 4T2g,4T1g-transitions are observed at 347 and 305 nm. The excited levels can be fitted with the parameters ⊿ = 28500 cm-1, B = 340 cm-1, ξ = 2500 cm-1 , allowing to calculate the nephelauxetic ratio β55 to 0.47. In the visible region extensive charge transfer transitions are observed. Based on the strong oxidizing character of Os(V) there is a bathochromic shift of corresponding bands of [OsCl6]- in relation to [OsCl6]2- of about 6600 cm-1 and to the isoelectronic [ReCl6]2- of about 13700 cm-1, respectively. From πt1u→dt2g the optical electronegativity is calculated to Xopt(Osv) = 2.49.

Effects of chemical composition and temperature of heating on the infrared spectra of Li-saturated dioctahedral smectites. (II) Near-infrared region

Clay Minerals ◽  
2000 ◽  
Vol 35 (5) ◽  
pp. 753-761 ◽  
Author(s):  
J. Madejová ◽  
J. Bujdák ◽  
S. Petit ◽  
P. Komadel
Keyword(s):  
Diffuse Reflectance ◽  
Near Infrared ◽  
Infrared Region ◽  
Hydroxyl Groups ◽  
Overtone Band ◽  
Stretching Vibration ◽  
Structural Hydroxyl ◽  
Near Infrared Region ◽  
Combination Bands ◽  
Ferruginous Smectite

AbstractDiffuse reflectance spectra in the near-infrared region are presented for Li-saturated smectites heated up to 200°C. The smectites included three montmorillonites, an Fe-beidellite and a ferruginous smectite. Unheated samples showed a complex band near 7060 cm-1 assigned to the first overtone of the OH-stretching mode of structural hydroxyl groups and bound H2O. The OH combination bands appeared in the 4600-4300 cm-1 region. Spectra of heated montmorillonites showed an upward shift and splitting of the OH-overtone band into two components near 7170 and 7110 cm-1. The presence of a band near 7170 cm-1, assigned to the overtone of the AlMgLiOH-stretching vibration, implied that local trioctahedral domains were created upon Li(I) fixation in the previously vacant octahedral positions of montmorillonites. The OH combination bands were shifted to higher frequencies and a new band appeared near 4472 cm-1 in the spectra of montmorillonites heated to temperatures in excess of 130°C. No features indicating Li(I) in the structure of Fe-beidellite or ferruginous smectite were observed in the NIR spectra.

scholarly journals Identification of Apple Varieties Using a Multichannel Hyperspectral Imaging System

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5120 ◽  
Author(s):  
Yuping Huang ◽  
Yutu Yang ◽  
Ye Sun ◽  
Haiyan Zhou ◽  
Kunjie Chen
Keyword(s):  
Hyperspectral Imaging ◽  
Spectral Range ◽  
Near Infrared ◽  
Imaging System ◽  
Visible Region ◽  
Infrared Region ◽  
Apple Variety ◽  
Apple Varieties ◽  
Spatially Resolved ◽  
Variety Classification

This paper reports the nondestructive detection of apple varieties using a multichannel hyperspectral imaging system consisting of an illumination fiber and 30 detection fibers arranged at source–detector distances of 1.5–36 mm over the spectral range of 550–1650 nm. Spatially resolved (SR) spectra were obtained for 1500 apples, 500 each of three varieties from the same orchard to avoid environmental and geographical influences. Partial least squares discriminant analysis (PLSDA) models were developed for single SR spectra and spectral combinations to compare their performance of variety detection. To evaluate the effect of spectral range on variety detection, three types of spectra (i.e., visible region: 550–780 nm, near-infrared region: 780–1650 nm, full region: 550–1650 nm) were analyzed and compared. The results showed that the single SR spectra presented a different accuracy for apple variety classification, and the optimal SR spectra varied with spectral types. Spectral combinations had better accuracies for variety detection with best overall classifications of 99.4% for both spectral ranges in the NIR and full regions; however, the spectral combination could not improve the results over the optimal single SR spectra in the visible region. Moreover, the recognition of golden delicious (GD) was better than those of the other two varieties, with the best classification accuracy of 100% for three types of spectra. Overall, the multichannel hyperspectral imaging system provides more spatial-spectral information for the apples, and the results demonstrate that the technique gave excellent classifications, which suggests that the multichannel hyperspectral imaging system has potential for apple variety detection.

Synthesis and optical, magnetic, and electrochemical properties of 5,10,15,20-tetraaryl-5,15-diazaporphyrin — tertiary amine conjugates

2020 ◽  
Vol 24 (01n03) ◽  
pp. 286-297 ◽  
Author(s):  
Keisuke Sudoh ◽  
Yuna Satoh ◽  
Ko Furukawa ◽  
Haruyuki Nakano ◽  
Yoshihiro Matano
Keyword(s):  
Electrochemical Properties ◽  
Tertiary Amine ◽  
Near Infrared ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Electron System ◽  
Infrared Region ◽  
Oxidation States ◽  
Resonance Spectroscopy ◽  
Absorption Bands ◽  
Amine Oxidation

We report on the synthesis and optical, magnetic, and electrochemical properties of nickel(II) and copper(II) complexes of 5,10,15,20-tetraaryl-5,15-diazaporphyrin–tertiary amine (TADAP–TA) conjugates. Metal-templated cyclization reactions of 9-(4-(dimethylamino)phenyl)amino-1-chloro-5-mesityldipyrrin and 9-(4-(diphenylamino)phenyl)amino-1-chloro-5-mesityldipyrrin (mesityl = 2,4,6-trimethylphenyl) with nickel(II) or copper(II) acetate afforded the corresponding metal(II) complexes of TADAP–TA. The 20[Formula: see text], 19[Formula: see text], and 18[Formula: see text] oxidation states of the DAP ring in the TADAP – TAs were reversibly interconvertible by redox reactions. NMR spectroscopy of the 20[Formula: see text] and 18[Formula: see text] Ni-TADAP – TAs revealed their antiaromatic and aromatic characters, respectively, whereas electron paramagnetic resonance spectroscopy of the 19[Formula: see text] Ni-TADAP–TAs showed effective delocalization of an unshared electron spin in the DAP ring. The interconversion between the three oxidation states of TADAP – TAs also caused a distinct change in the optical properties of the DAP [Formula: see text]-electron system. Notably, all the 18[Formula: see text] dications exhibited weak and broad absorption bands in the near infrared region owing to the charge-transfer from the peripheral tertiary amine units (donor) to the cationic DAP center (acceptor). Cyclic voltammetry of TADAP – TAs exhibited the reversible 20[Formula: see text]/19[Formula: see text] and 19[Formula: see text]/18[Formula: see text] redox couples and the irreversible amine oxidation at the periphery. The electrochemical oxidation of the Ni-TADAP–triphenylamine conjugate generated reactive ammoniumyl radicals, which underwent intermolecular coupling to form a polymer of TADAP–TA on the electrode surface.

scholarly journals Synthesis of gold nanorods and their performance in the field of cancer cell imaging and photothermal therapy

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Naseer Ullah Khan ◽  
Jing Lin ◽  
Muhammad Rizwan Younas ◽  
Xukun Liu ◽  
Liming Shen
Keyword(s):  
Gold Nanorods ◽  
Self Assembly ◽  
Photothermal Therapy ◽  
Near Infrared ◽  
Malignant Tumors ◽  
Infrared Region ◽  
Plasmon Band ◽  
Longitudinal Band ◽  
Growth Method ◽  
Unique Shape

AbstractCancer is one of the most common incident in the world, with malignant tumors having a death rate of up to 19%. A new method of treating cancer cells effectively with minimal cytotoxicity is needed. In the field of biomedicine with unique shape-dependent optical properties, gold nanorods (GNRs) have attracted worldwide interest. These nanorods have two distinct plasmon bands. One is transverse plasmon band in the area of visible light, and the other is longitudinal band of plasmons in near infrared region. These specific characters provide promise for the design of new optically active reagents that simultaneously perform light-mediated imaging and photothermal cancer treatment. We begin our review by summarizing the latest developments in gold nanorods synthesis with a focus on seed-mediated growth method. Nanorods spontaneous self-assembly, polymer-based alignment and its applications as a novel agent for simultaneous bioimaging and photothermal cancer therapy are listed in particular.

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