Absorption spectroscopy

Silver nanoparticles (Ag NPs) were synthesized and characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and absorption spectroscopy. Using Debye-Scherrer’s formula and the result of the XRD spectrum, the size of the Ag NPs was estimated at approximately 8 nm.

7p viengfa 28-10-2024 0 0   Download

Silver nanoparticles (Ag NPs) with a size of around 9 nm were fabricated and quantified through fluorescence quenching of rhodamine B (RhB). A series of solutions composed of RhB with various concentrations of Ag NPs ranging from 0.09 pM to 0.98 pM were prepared, and optical properties were investigated by absorption and fluorescence spectroscopies.

8p viengfa 28-10-2024 2 1   Download

The aim of this study was to design and characterize a NdFeO3-based photocatalyst prepared by sol-gel method for treatment of oily wastewater. Different characterization techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), UV–vis spectrophometer were used to elucidate the structure, morphology, surface functional groups, and optical absorption properties of the prepared NdFeO3 photocatalyst.

6p vikwong 29-09-2024 2 1   Download

The shift in Raman and change in absorption spectra are evidence that would relate to the structure change or disorder and impurity in the samples. From the above results, a critical substituent content at which the structural phase change takes place is shown.

7p tamynhan8 04-11-2020 14 2   Download

This indicates that the Ce ion has an effect on the structure of ZnWO4 and suggests a solubility limit of Ce in ZnWO4 ceramics. In addition, we also calculated the Raman active modes by using group theory and we received 18 modes in Raman active and 16 modes in IR active. The absorption measurement indicates the band gap of ZnWO4 decreases with increasing Y content. The reasons for the above changes are discussed in this presentation.

5p tamynhan8 04-11-2020 17 1   Download

Borotellurite glasses were prepared by melt quenching technique. Amorphous nature of samples was confirmed through X-ray diffraction (XRD) patterns. Effect of B2O3 content on the structure of glass network was studied through Fourier-transform infrared spectroscopy (FTIR) spectra. Optical band gap and Urbach energy were found from analysis of optical absorption spectra. Thermal studies were carried out by using Differential thermal analyzer (DTA) measurements.

8p tamynhan6 14-09-2020 14 2   Download

The CdSe, type-II CdSe/CdTe core/shell and type-II/type-I CdSe/CdTe/ZnS core/shell/shell quantum dots (QDs) were successfully synthesized in a noncoordinating solvent. The phonon characterizations, optical properties and structures of the synthesized QDs were characterized by Raman scattering (RS) spectra, photoluminescence (PL) spectroscopy, PL-decay lifetime, absorption spectroscopy (Abs), and X-ray diffraction (XRD).

11p tamynhan6 14-09-2020 15 2   Download

The presence of heterocyclic moiety in diverse compounds, strongly indicative of the desired effect on physiological activity, and it reflects on efforts to find useful synthetic drugs.

12p tocectocec 25-05-2020 16 1   Download

Bài giảng Phương pháp quang phổ hấp thụ nguyên tử (Atomic Absorption Spectroscopy AAS) nêu lên nguyên tắc đo ASS, cấu tạo máy quang phổ hấp thụ nguyên tử, bộ phận tán sắc, máy thu nhận tín hiệu, chọn các thông số của máy thật tối ưu.

28p maiyeumaiyeu09 16-09-2016 378 70   Download

Mục tiêu nghiên cứu của luận án: Chế tạo hai hệ xúc tác CS và MCS, đặc trưng các xúc tác bằng các phương pháp hóa lý hiện đại, trong đó sử dụng phương pháp phổ hấp thụ tia X (X-Ray Absorption Spectroscopy - viết tắt là XAS) - phương pháp phân tích cấu trúc mới, hiện đại, để đặc trưng sâu hệ thống liên kết trong xúc tác.

184p change12 30-06-2016 99 9   Download

Mục tiêu nghiên cứu của luận án: Chế tạo hai hệ xúc tác CS và MCS, đặc trưng các xúc tác bằng các phương pháp hóa lý hiện đại, trong đó sử dụng phương pháp phổ hấp thụ tia X (X-Ray Absorption Spectroscopy – viết tắt là XAS) – phương pháp phân tích cấu trúc mới, hiện đại, để đặc trưng sâu hệ thống liên kết trong xúc tác;... Sau đây là bản tóm tắt của luận án.

26p change00 05-05-2016 77 5   Download

Methanol:coenzyme M methyltransferase from methanogenic archaea is a cobalamin-dependent enzyme composed of three different subunits: MtaA, MtaB and MtaC. MtaA is a zinc protein that catalyzes the methylation of coenzyme M (HS-CoM) with methylcob(III)alamin. We report zinc XAFS (X-ray absorption fine structure) results indicating that, in the absence of coenzyme M, zinc is probably coordinated by a single sulfur ligand and three oxygen or nitrogen ligands. In the presence of coenzyme M, one (N/O)-ligand was replaced by sulfur, most likely due to ligation of the thiol group of coenzyme M....

7p research12 01-06-2013 52 5   Download

Although of major impact in terms of biological and environmental haz-ards, interactions of actinide cations with biological molecules are only par-tially understood. Human serum transferrin (Tf) is one of the major iron carriers in charge of iron regulation in the cell cycle and consequently con-tamination by actinide cations is a critical issue of nuclear toxicology. Combined X-ray absorption spectroscopy (XAS) and near infrared absorp-tion spectrometry were used to characterize a new complex between Tf and Np (IV) with the synergistic nitrilotriacetic acid (NTA) anion....

0p awards 06-04-2013 49 3   Download

Owing to theuseof porphyrins inphotodynamic therapy for the treatment of malignant tumors, and the preferential interaction of lectins with tumor cells, studies on lectin– porphyrin interactionareof significant interest. In this study, the interaction of several free-base and metalloporphyrins withMomordica charantia(bitter gourd) lectin (MCL) was investigated by absorption spectroscopy. Difference absorp-tion spectra revealed that significant changes occur in the Soret band region of the porphyrins on binding to MCL....

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Escherichia coliflavorubredoxin (FlRd) belongs to the family of flavodiiron proteins (FDPs), microbial enzymes that are expressed to scavenge nitric oxide (NO) under anaerobic conditions. To degrade NO, FlRd has to be reduced by NADH via the FAD-binding protein flavorubredoxin reduc-tase, thus the kinetics of electron transfer along this pathway was investi-gated by stopped-flow absorption spectroscopy.

10p galaxyss3 21-03-2013 25 4   Download

Native and Ca 2+ -depleted light-harvesting–reaction center core complexes (LH1–RC) from the photosynthetic bacterium Thermochromatium(Tch.) tepidum exhibit maximal LH1–Qy absorption at 915 and 889 nm, respec-tively. To understand the structural origins of the spectral variation, we performed spectroscopic and structure modeling investigations.

11p vinaphone15 27-02-2013 51 4   Download

NMR is an experiment in which the resonance frequencies of nuclear magnetic systems are investigated. NMR always employs some form of magnetic field (usually a strong externally applied field B0) NMR is a form of both absorption and emission spectroscopy, in which resonant radiation is absorbed by an ensemble of nuclei in a sample, a process causing detectable emissions via a magnetically induced electromotive force.

20p qdung92ct 03-07-2012 113 10   Download

Deviations from Beer’s law (i.e. deviations from the linearity of absorbance vs. concentration): – Intermolecular interactions at higher concentrations – Chemical reactions (species having different spectra) – Peak width/polychromatic radiation Beer’s law is only strictly valid with single-frequency radiation Not significant if the bandwidth of the monochromator is less than 1/10 of the half-width of the absorption peak at halfheight.

0p qdung92ct 03-07-2012 72 4   Download