Molecular dynamics simulations and laser kinetic absorption spectroscopy have been used to study the molecular oxygen (O₂) migration in the isolated β chains of human hemoglobin. The insertion of xenon (Xe) atoms into the isolated chains has been found to decrease the time constant of the slowest component of the geminate O₂ rebinding to the protein. This change is caused by a decrease in an intra-protein space available for the O₂ migration after the insertion of the inert gas into the Xe-binding sites of the protein. The molecular dynamics simulations have revealed that during the course of the geminate recombination to the isolated β-chains, the O₂ molecule visits both Xe2 and Xe1 site of the protein. The amino acids involved in the formation of the primary and secondary docking sites of the protein have been determined. The obtained results are important for understanding the mechanism of O₂ binding by both native tetrameric human hemoglobin and artificial oxygen carriers based on heme proteins.

The rates of chemical trapping of singlet oxygen were studied in aerated water, ethanol, and deuterium oxide upon direct excitation of oxygen molecules by radiation of diode and fiber lasers, corresponding to the fundamental (1273 nm) and vibrational (1070 nm) absorption bands of oxygen molecules. As a trap, 1,3- diphenylisobenzofuran was used, which was solubilized in aqueous systems by adding 0.05 M sodium dodecyl sulfate. It is established that, just as in the organic media we have recently studied, in aerated alcohol and aqueous systems the quantum efficiency of the trap oxygenation under laser excitation at 1070 nm is two orders of magnitude lower than that under excitation at 1273 nm. The significance of these data for the use of IR lasers in phototherapy is discussed.

Quantum-chemical modeling of the structure and vibrational states of 4-coordinated Ni-complexes of octaalkylporphyrins (Ni-OAP) in the ground and in a series of (d, d), (π, d) and (π, π) excited states has been carried out. The calculated resonance Raman spectrum (RRS) of Ni(II)-octaethylporphyrin (Ni-OEP) in ³(d_z2, d_x2-y2) configuration is attributed to the experimental spectrum obtained at a delay of ~2 ps after excitation, as well as the spectrum recorded during pulsed nanosecond excitation in the saturation regime. The calculated data indicate the presence in the Ni-OEP solution of a large number of conformers that differ in the amount of macrocycle corrugation, which leads to line broadening in the RRS spectra. It is shown that the absence of spectral signs of ³(π, π*) state in the relaxation kinetics of the electronic excitation energy of Ni-OAP may be due to the fact that, in contrast to the corresponding Cu-, Zn-, and Pd-complexes of porphyrins with large ionic radius of the metal, for them in this state there is no local minimum. The effect of steric crowding for the mono-meso-methyl substituted Ni(II)-ethioporphyrins on the frequencies of structurally sensitive vibrations v₁₀, v₂, v₃, v₄ in the RRS spectra in the ground and excited ³(d_z2, d_x2-y2) state is studied. It is shown that the transition to the electronic configuration ³(d_z2, d_x2-y2) is accompanied by a significant de-crease in the macrocycle corrugation deformation.

Spectral-luminescent characteristics of the solution of 10-phenyl-5,15-di-(4,6-dichloropyrimidinyl)-corrole at 77 K have been studied. It has been found that in the lowest T₁ triplet state of the long-wavelength T1-tautomer, the effective NH-tautomerization occurs, resulting in the phosphorescence being emitted from the short-wavelength T2-tautomer only. It has been found that at 77 K the acid-base equilibrium shifted and a certain fraction of the molecules has been deprotonated. The fluorescence and phosphorescence spectra of the deprotonated form have been identified, and it has been found that the energy gap for the deprotonated form DE(S₁ - Т₁) = 5570 cm^-1 is as large as that one for the free bases. The molecular conformation of NH-tautomers for the series of corroles with different peripheral substitution architecture has been optimized by the density functional theory method, their electronic absorption spectra and the energy gap DE(S₁-T₁) have been calculated. It has been established that an increase in the energy gap DE(S₁-T₁) is due to the increase in the energy mismatch DE(LUMO-LUMO+1), and the observed trend is common for all the types of studied molecular systems: both NH-tautomers of the free base and the deprotonated form. It has been proposed that such a trend is the inherent property of the contracted corrole macrocycle, which has an excess of electron density compared to the porphine.

The key biophysical characteristics of human skin fibroblasts in a free state and as a part of a biomedical cell product (cells with a carrier “Collost” gel) were studied using flow cytometry and fluorescent probes. Data were obtained on the preservation of the intact state of fibroblasts in combination with the carrier, namely, the content of ionized calcium, reactive oxygen species in the cytoplasm of cells and the level of microviscosity of the lipid bilayer of cell membranes. It is shown that the “Collost” gel does not induce oxidative stress in fibroblasts, cell membranes are not damaged and there is no increase in the content of calcium ions in the cytoplasm of fibroblasts, the microviscosity of the lipid bilayer of membranes does not change, which is important for the use of the “Collost” gel carrier for the formation of a biomedical cell product and its subsequent use in cell therapy.

Enhancement by halomethanes (CCl₄, CHBr₃) of photosensitized by Zn-tetraphenylporphin and Zn-tetramethylpyridylporphyrin destruction of protein tryptophanils and lipid peroxidation in isolated erythrocyte membranes has been studied. It is shown that the effect is due to photoinduced electron transfer from Zn-porphyrins to halomethanes with the formation of highly reactive halomethyl radicals. Hydrophilic Zn-tetramethylpyridylporphyrin is more active in halomethane-mediated photosensitization of membrane protein damage, while hydrophobic Zn-tetraphenylporphin is more effective in photosensitizing lipid oxidation.

The aggregation studies of tricationic chlorin photosensitizer (H₂Chl³⁺, PS) and PS interaction with passive delivery vehicles Tween 80 and PVP in aqueous solutions have been carried out by 1D and 2D NMR. It is demonstrated that NMR spectroscopy is a powerful tool to detect both nanoaggregates at about 10^-3 mol/kg and associates formed in H₂Chl³⁺ solution at PS concentration lower by two orders of magnitude. At the same time NMR is able to identify molecular fragments of PS responsible for the aggregation. Addition of solubilizers as Tween 80 and PVP leads to the destruction of PS nanoaggregates and the formation of stable complexes with potential carriers, while the associated forms of the macrocycle studied are presented in a solution. The results obtained are consistent with the data of absorption and fluorescence spectroscopy as well as dynamic light scattering. The molecular complex of water-soluble H₂Chl³⁺ with the PVP macromolecule in aqueous solution is additionally stabilized due to H-bonding of the PS amide NH proton and oxygen atom of the polymer carbonyl group.

We performed quantum chemical modeling of the optimal geometry of naringenin, apigenin and menadione and evaluated their electronic properties and interactions with artificial liposomal membranes using fluorescence probe spectroscopy. The fluorescence analysis demonstrated that the flavonoids and quinones under study strongly interacted with 1,2-dimyristoyl-sn-glycero-3-phosphocholine liposomal membranes. Using the fluorescent probes TMA-DPH and DPH, incorporated in the lipid bilayer, we showed that apigenin and naringenin (5-50 µM) and menadione (50 µM) decreased the microfluidity of the liposomal membrane bilayer at different depths and apigenin rather than menadione and naringenin effectively quenched the fluorescence of these probes TMA-DPH and DPH. Interaction of the studied compounds with the membranes depended on the polarity, volume, geometry and water solubility of the molecules. Using the Laurdan probe we observed that naringenin and menadione dose-dependently transferred the bilayer to a more ordered state, whereas apigenin decreased the order of lipid molecule packing and increased hydration in the region of polar head groups due to incorporation of the effectors into the liposomes. The torsion angle between the rings of the planar menadione and apigenin molecules was equal to 180°, while that of the naringenin molecule was equal to 86.4°, respectively. The cranberry flavonoids in the glycosylated form (25-50 µg/mL) slightly increased the microfluidity of the liposomal membrane in the region of the polar head groups.

Protein tyrosine nitration is considered as one of the types of post-translational modification of proteins, indicating disruptions in metabolic and signaling functions of nitric oxide ^•NO and development of oxidative nitrosative stress. We have considered the non-enzymatic pathway of protein nitration under the action of visible light in the presence of riboflavin and nitrite. Using mass spectrometry method, it is shown that redox processes photosensitized by riboflavin and involving nitrite and tyrosine/tyrosyl residues lead to nitration of tyrosyl residues Tyr-103 and Tyr-146 in polypeptide chain of horse heart myoglobin. Possible role of riboflavin and other natural photosensitizers in modification and damage of proteins in conditions when the body is exposed to intense visible light in the presence of nitrites in the blood is discussed.

Based on spectral-luminescent data and results of quantum-chemical calculations (method MM+) interface phenomena and spectral properties changes of interacting components are analyzed for self-assembling nanoassemblies formed via electrostatic interactions of positively charged tetra-methyl-pyridyl porphyrins (free bases) and negatively charged glutathione stabilized core/shell semiconductor quantum dots AgInS/ZnS/GSH (QD) in water (pH 7.5) at 298 K ambient temperature. In frames of elaborated size-consistent quantum chemical atomistic 3D model of QD we propose the detailed physicochemical subsequence of the processes taking place on QD surface upon interaction with the attached porphyrin molecule, accompanied by a fast formation of Zn-porphyrin complex which is directly fixed on the QD SH surface. The obtained results are the basis of the quantitative analysis of pathways and mechanisms of the excitonic excitation relaxation in nanoassemblies of this type.

In metal-dielectric nanostructures with metal inhomogeneities with the size of about 10-100 nm, strong local concentration of electromagnetic radiation at the frequencies of incident (primary) and emitted (secondary) radiation occurs simultaneously with a considerable growth of nonradiative transitions rate (fluorescence quenching). We report on general principles of using metal-dielectric nanostructures for the enhancement of fluorescence and on experimental implementation of these principles for organic molecules including biomolecules marked with fluorescent labels.

Prototypes of chip systems have been created in the form of nanopillars from DNA complexes with CdSe/CdZnSe/ZnS quantum dots immobilized on a plasmonic gold film using the technology of vacuum deposition and inorganic synthesis. The design of nanopillars and the presence of terminal DNA labeled with Cy3 cyanine dyes makes it possible to carry out the reaction of hybridization of this terminal strand with complementary DNA and to control this process by changing the surface-enhanced Raman scattering (SERS) signal and fluorescence. The effect of molecular recognition of complementary DNA is accompanied by a change in the SERS spectrum, an increase in the fluorescence intensity by a factor of 20, and a decrease in the fluorescence decay time.

A comparison of the longitudinal distributions of the maximal intensity in Bessel light beams (BLB) of different orders with analogical distributions in Gaussian and Laguerre-Gaussian light beams of the corresponding orders is made. The concept of the “dangerous zone” of the BLB is introduced and the method for determining its length is proposed. The maximum value of the intensity I0 of the initial Gaussian or Laguerre-Gaussian light beam is initially chosen not to exceed the optical damage threshold of the optical elements and objects used. The “dangerous zone” of the BLB is a region of space behind the axicon, in which the maximum intensity value in the BLB exceeds I₀. The length of the “dangerous zone” is taken to be the largest distance z_K behind the axicon, for which the maximum intensity in the cross section of the BLB is equal to I₀. Additionally, the distance z_E from the axicon is determined, at which the intensity values on the BLB's axis and in its peripheral annular field are aligned. In this cross section the maximum intensity values in the BLB of the 0th, 1st, and 2nd orders are guaranteed to be less than I₀, but the transverse size of the light beam is not yet too large. With the help of mathematical modeling methods the relative (in units of the BLB's existence length z_wI) values z_E and z_K for the zero and higher (from the first to the ninth) orders of the BLB are calculated. It is shown that when designing optical systems using the conical geometry of the BLB, it is advisable to place objects with low optical damage threshold at distances greater than z_K, and the most energy efficient for the same given radius of the initial Laguerre-Gaussian beam in terms of the level I₀/e² is the 1st order BLB in the region from z_K to z_E.

Random lasing was achieved in CdS and Zn_0.65Cd_0.35Se micropowders at optical pump levels of 0.1-2 MW/cm² with N₂-laser radiation at the wavelength of 337 nm. The values of the random generation thresholds were 820 kW/cm² for CdS micropowder and 740 kW/cm² for Zn_0.65Cd_0.35Se micropowder. The introduction of Ca(Al_0.1Ga_0.9)₂S₄:Eu²⁺ and Ca₄Ga₂S₇:Eu²⁺ chalcogenides into the mixture to micropowders of CdS and Zn_0.65Cd_0.35Se solid solutions led in both cases to a drop in the random generation threshold to 520 and 550 kW/cm², respectively, as well as to the appearance of the structure of laser radiation lines and an increase in their intensity. This may be caused by an increase in the number of feedback loops due to the introduction of additional scatterers.

We performed experimental studies of iron oxyhydroxide nanostructures formation process by low- temperature plasma electrolysis, including spectroscopic investigation of glow discharge plasma at atmospheric pressure between a metal electrode and liquid. The results of characterization of the structure and composition of the formed nanoparticles are under discussion.

The effect of the properties of granular materials (catalyst ZnO, sea salt NaCl) and plant seeds during their treatment in plasma of dielectric barrier discharge (DBD) on the combustion mode and discharge power was investigated. Optical emission spectroscopy methods were used to investigate the discharge spatial structure. Electron, vibrational, and rotational temperatures of plasma averaged over the cross section of the discharge gap were determined from the analysis of intensity distribution in rotationally unresolved spectral bands of (2+) N₂ and (1-) N₂⁺. It was observed a transition from the DBD filamentary mode to the combination of filamentary and surface discharges when the treated materials were presented in the discharge that was accompanied by an increase in the power dissipated in the discharge and the vibrational temperature in the near-electrode region in the vicinity of the material.

The NMR method has been used to study the composition of Scotch pine oleoresin in concentrated and dilute solutions in 8 deuterated solvents and carbon tetrachloride (ССЦ). It has been established that dilute solutions in chloroform-d, methylene chloride-d₂ and acetic acid-d₄ contain significantly less levopimaric acid than the concentrated ones, while the amount of abietic acid increases. It is assumed that the high rate of isomerization of levopimaric acid to abietic acid in dilute solutions at room temperature is due to catalytic reactions associated with the acidic nature of solvents, which must be taken into account when performing NMR-analysis. During the “aging” of oleoresin, reactions with atmospheric oxygen occur with the formation of dehydroabietic acid. Comparative analysis has shown that deuterated benzene is the most acceptable solvent when determining the composition of oleoresin with NMR method.

Research of the composition of phenolic compounds in extracts of leaf blades of cloudberry (Rubus chamaemorus L.) populations of the reserves “Lonno”, “Yelnya”, “Boloto Mokh”, and “Zhada” was conducted. The highest content of phenolic compounds was observed in the female clone of the “Lonno” population and amounted to 651.54±21.64 mg-equiv of gallic acid/g of extract, of which 53.5±15.01 mg-equiv of rutin/g of flavonoid extract. The following phenolic compounds were identified in the extracts with chroma- to-mass spectrometry: quercetin-3-O-xyloside, ellagic acid, quercetin-3-O-glucoside, quercetin-3-O-glucuronide, kaempferol-3-β-D-glucopyranoside, chlorogenic acid, rutin. The content of kaempferol-3-β-D-glucopyranoside, quercetin-3-O-glucoside, ellagic acid, and rutin was determined.

It has been shown that the effect of soil drought at the initial stages of stress development does not cause significant destructive processes in the photosynthetic membranes of barley plant leaves, what has been evidenced by the absence of disturbances in the photochemical activity of photosystems 1 and 2. Moisture deficiency in the soil causes the activation of the adaptation mechanism, which consists in the redistribution of energy between PSs, which minimizes the photodestructive effect. It has been established that in the leaves of barley plants during drought, the non-photochemical quenching of chlorophyll fluorescence, which is to a greater extent its regulated component, is significantly reduced. This is potentially dangerous, since the chloroplasts of such plants will be vulnerable to photooxidative stress under prolonged stress. The suppression of the controlled energy dissipation in the photosynthetic membrane during drought may be the limiting factor determining the resistance of barley plants to such stress.

A comparative study of the spectral-luminescent properties of mono- and tetra-meso-allyloxy-substituted porphyrins has been performed. The efficiency of the photosensitized formation of singlet molecular oxygen by porphyrins has been determined. The regularities of the formation of chlorin and bacteriochlorin structures in the process of radical-chain copolymerization of acrylamide with the investigated porphyrins are considered. The mechanism of their recovery is discussed.

One of the potentially transformative areas of scientific development is to achieve superconductivity at room temperature. Recently, the photochemical synthesis was carried out to prepare carbonaceous sulfur hydride (CSH) systems with room-temperature superconductivity at high pressure. In this work, we present a first-principles study aiming to unravel the photoreaction of sulfur with molecular hydrogen using the time-dependent excited-state molecular dynamics (TDESMD) methodology. Individual TDESMD trajectory provides details about reactions that lead to a number of allotropes of sulfur and their hydrogenated forms. Simulated mass spectra based on an ensemble of TDESMD trajectories provide the distribution of sulfanes along reaction pathways. It is found that the photoreaction starts with ring opening of cyclic S₈, which may then react with two H radicals to form S₈H₂ as a result of the homolytic dissociation of H₂. The sulfur cluster will undergo the elimination of small fragments, which can later recombine into a variety of sulfanes. The most abundant fragments generated along trajectories are H₂S, S₄H₂, and S₈H₂. The final sulfur-bearing products are a mixture of sulfanes with various chains and rings. The mechanistic and conformational information obtained from this work allows us to better understand the photoreaction, and potentially, give insights into the preparation of high T_c materials using similar reactants.

An experimental platform of laser-induced breakdown spectroscopy (LIBS) is used to obtain the spectral information of seven ER8 high-speed train wheel samples with different surface roughnesses; the correlations between their spectral line intensities and the ratios of spectral line intensities to the surface roughnesses of the samples are investigated. The results show that the spectral line intensities of the base element Fe and the alloying elements Cr, Mo, and V, the intensity ratios of ion lines to atomic lines, and the spectral line intensity ratios of alloying elements to base elements are all correlated with the surface roughnesses of the samples to different degrees. In addition, random forest (RF) models with spectral line intensities and spectral line intensities with spectral line intensity ratios as variables are established using the correlations. The study shows that it is feasible to qualitatively analyze the surface roughnesses of high-speed railway wheel materials using laser-induced breakdown spectroscopy with an RF algorithm; this technique can be used to measure and evaluate the surface roughnesses of wheels in the field and provide some basis for the application of LIBS technology to the study of high-speed railway wheels with different surface roughnesses.

The traditional way of measuring blood glucose causes pain and inconvenience to patients. Nearinfrared spectroscopy is a promising noninvasive alternative. However, the prediction accuracy of the currently used quantitative blood glucose model for near-infrared spectroscopy decreases when a patient's physiological state changes. Therefore, we propose an improved sparrow search algorithm (ISSA) to optimize the initial weights and thresholds of extreme learning machines (ELM) in this paper. We used a tent chaotic map to improve the diversity of the SSA population. We also adopted reverse learning to initialize the population and expand the population search range, which further improved the search performance of the SSA. The predicted results of the ISSA-ELM model were more accurate and generalizable than those of the SSA-ELM model. Clarke error grid analysis showed that the proportion of predicted samples falling into the A region was 90%, and the proportion falling into the B area was 10%, which is in accordance with clinical requirements. Therefore, this model has strong potential for application in non-invasive detection of human blood glucose.

A simple, sensitive, and rapid bioanalytical method was developed for the first time for simultaneous es-timation of naproxen sodium (NPX) and diphenhydramine hydrochloride (DPH) in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The isotope-labelled analogs, naproxen 13CD₃ and diphenhydramine D₅ hydrochloric acid, were used as the internal standards. The analytes were extracted from 50 µL of human plasma employing a simple protein precipitation technique. The separation of analytes was carried out on a Zodiac C₁₈ column (50x4.6 mm, 3 µm) using a mixture of HPLC grade acetonitrile and 5 mM ammonium acetate buffer in 0.025% formic acid (60:40, v/v) at a flow rate of 1.0 mL/min. The method showed linearity within the concentration ranges 400 to 120,000 ng/mL for NPX and from 0.80 to 240 ng/mL for DPH with r² > 0.99. The method was validated as per the US FDA guidelines and the results were found to be within the acceptance limits. The method was successfully applied for the pharmacokinetic study of both drugs simultaneously after an oral dose of two caplets, each containing NPX 220 mg and DPH 25 mg under fed conditions in human volunteers. Incurred sample reanalysis was also performed to authenticate the reproducibility of the method.

Carbon dots (CDs) are of great significance for metal ion detection. Herein, CDs without surface functional groups were synthesized through a simple one-step hydrothermal method using 4,4 '-bipyridine as the carbon source. The results showed that the synthesized CDs have good selectivity for Fe³⁺ detection, and the CDs respond well to metal ions as Lewis bases. This detection method is unlikely to be affected by sewage systems because it has excellent sensitivity. The detection range for Fe³⁺ concentrations is between 1.0×10^-8 and 1.0×10² mol/L, and the detection limit is 1.0×10^-8 mol/L.

An extractive visible spectrophotometric procedure has been developed for diazepam (DZ) determination in pure and pharmaceutical forms using methyl orange (MO) and bromophenol blue (BPB) dyes. The proposed method was based on the formation of an ion-pair colored complex between diazepam and indicators via extracting them into chloroform whereby absorbance measured at 411 and 415 nm, respectively. The extracts are intensely colored and very stable at room temperature. The molar absorptivity for DZ-MO and DZ-BPB ion pairs were determined to be 5.3×10³ and 6.66×10³ L/mol • cm, respectively. The stoichiometry of the reaction was found to be 1:1 in all cases and the conditional stability constant (K_f) of the complexes was calculated. The effective range of concentration for an accurate determination as ascertained from Ringbom's plot was obtained at 16.67-50 μg/mL. The proposed method has been applied successfully to the analysis of drug dosage forms and no interference was observed from common excipients present in pharmaceutical formulations. The results obtained by the proposed method were statistically compared by means of the student t-test and by the variance ratio, and F-test with the HPLC method. Here it is shown to be in excellent agreement with the official method.

A chitosan-functionalized magnetic graphene oxide composite was used to preconcentrate, separate, and determine the trace amounts of lead ions (Pb²⁺) in aqueous samples. Graphite furnace atomic absorption spectrometry was applied to determine Pb²⁺ concentration in aqueous solutions. Sodium diethyldithiocarbamate was applied as a chelating agent in this study. Fourier transform infrared spectra, X-ray diffraction, thermogravimetric analysis, vibrating sample magnetometer, and scanning electron microscope were applied to characterize the magnetic properties, surface morphology, and chemical structure of the synthesized composite. Factors that affected extraction efficiency were evaluated and optimized. Under optimal conditions, the linearity limit for the determination of Pb²⁺ ion concentration was 0.70-100.00 μg-L with a correlation coefficient of 0.9981. The quantitation and detection limits were 0.73 and 0.21 μg/L, respectively. The value of the preconcentration factor was found to be 40, and the repeatability coefficient of the proposed method was calculated as 2.58% (RSD%). Further, the isothermal models, kinetic data, and thermodynamic studies were investigated. Overall, the proposed method is an effective technique with many advantages such as high sensitivity, economical procedure, fast and easy separation ability with excellent recovery, and being environmentally friendly to determine trace amounts of Pb²⁺ ions in various aqueous samples.

A theoretical investigation of spatiotemporal dynamics of an intense laser pulse with a q-Gaussian spatial irradiance profile interacting with collisionless plasma has been presented. In particular, the dynamics of pulse width and beam widths of the laser pulse have been investigated in detail. Using variational theory, nonlinear partial differential equation governing the evolution of the pulse envelope has been reduced to a set of coupled ordinary differential equations for the pulse width and beam widths of the laser pulse. The differential equations thus obtained have been solved numerically to envision the interplay between self-focusing and self-compression of the laser pulse.

Laser-induced breakdown spectroscopy (LIBS) technique is employed for quantitative analysis of aluminum samples by different classical machine learning approaches. A Q-switch Nd:YAG laser at a fundamental harmonic of 1064 nm is utilized for the creation of LIBS plasma in order to predict constituent concentrations of the aluminum standard alloys. In the current research, concentration prediction is performed by linear approaches of support vector regression (SVR), multiple linear regression (MLR), principal component analysis (PCA) integrated with MLR (PCA-MLR), and SVR (PCA-SVR), as well as nonlinear algorithms of artificial neural network (ANN), kernelized support vector regression (KSVR), and the integration of traditional principal component analysis with KSVR (PCA-KSVR), and ANN (PCA-ANN). Furthermore, dimension reduction is applied to various methodologies by the PCA algorithm in order to improve the quantitative analysis. The results indicated that the combination of PCA with the KSVR algorithm model had the best efficiency in predicting most of the elements among other classical machine learning algorithms.

Sm³⁺ doped and RE³⁺ (RE = Dy, Er, Gd, La, Nd, Tb) co-doped CaB₆O₁₀ phosphors were prepared at 800°C by the solid-state reaction method. The obtained powders were structurally characterized by X-ray diffraction and Fourier transform infrared analyses. The influences of co-doping rare earth ions on their luminescent properties were also investigated. The emission spectra of the CaB₆O₁₀:Sm³⁺ phosphors consisted of some sharp emission peaks of Sm3+ ions centered at 561, 601, 649, and 708 nm, generating bright orange-red light. The concentration quenching occurred when x equals 0.05 for CaB₆O₁₀:xSm³⁺ phosphor. No remarkable differences were found from excitation spectra of co-doped phosphors CaB₆O₁₀:Sm³⁺, RE³⁺ in contrast with that of phosphor CaB₆O₁₀:Sm³⁺. The introduction of charge compensator RE³⁺ (RE = Dy, Er, Gd, La, Nd, Tb) into the host reduced the luminescence intensity of the CaB₆O₁₀:Sm³⁺ phosphors.

The SrWO₄:RE³⁺ (RE = Eu, Sm, Pr) fluorescent powders are synthesized using a high-temperature solid-state method. The phase structures and morphologies of the fluorescent powders are examined using X- ray diffraction and field-emission scanning electron microscopy, respectively. The results reveal that pure phase SrWO₄ can be prepared via calcination at 900 °C for 4 h and that doping with rare-earth ions has no effect on the crystal phase of the fluorescent powders; SrWO₄ powders doped with three rare earth ions all form spherical-like structures. The luminescence properties of the samples are evaluated using a fluorescence spectrometer, and the excitation and emission spectra of the SrWO₄:RE³⁺ (RE = Eu, Sm, Pr) fluorescent powders are analyzed. The results indicate that SrWO₄:Eu³⁺ fluorescent powder can be effectively excited by ultraviolet light at 395 nm and emit red light at 615 nm when a doping concentration of Eu³⁺ is 7%; Sm³⁺ and Pr³⁺ doped SrWO₄ can emit red light at 650 and 687 nm when excited at 406 nm and 460 nm, respectively, with a doping concentration of 5% each. A W-LED device with SrWO₄:Eu³⁺ pink fluorescent powder and a 395 nm UV chip is successfully assembled. The chromaticity coordinates of the device are (0.3055, 0.3532), exhibiting prominent white light. SrWO₄:RE³⁺ (RE = Eu, Sm, Pr) fluorescent powders are expected to be red fluorescent powders for UV-excited white LEDs.