The luminescence of nanocrystalline ZnS-Mn powder obtained by the method of self-propagating high-temperature synthesis is studied. The luminescence was excited by the chemical reaction of recombination of hydrogen atoms on the surface. There is described the technique of synthesis and ZnS-Mn characteristics obtained using X-ray diffraction analysis and EPR spectra, and also non-stationary luminescent methods for studying elementary acts of interaction of hydrogen with a surface. The mechanisms of reaction of recombination of H-atoms on the surface are established, and a mechanism is developed for the excitation of heterogeneous chemiluminescence of nanocrystalline ZnS-Mn by atomic hydrogen. Criteria for sensors of atoms in gases are determined. It is shown that the synthesized ZnS-Mn samples can be used to construct highly sensitive inertialess chemiluminescent sensors for detecting hydrogen atoms in gases.

We have synthesized new cyano-bridged hetero-metallic polymeric complexes [M(NH₃)(2mpz)Ni(CN)₄] ·nH₂O in the powder form for the first time. Their structures were determined by elemental and spectral (infrared and Raman) analyses. In the complexes, the center of the nickel atom binds with four cyano ligands and shows a square planar geometry. In addition, the metal atoms (Cu(II) or Zn(II)) are linked to the ring nitrogen atom of one 2mpz ligand, one ammonia ligand, and four bridging cyano groups and show a distorted octahedral geometry. The spectral features suggest that these complexes are similar to each other and their structures consist of |M – Ni(CN)4|∞ type polymeric layers with the ligands (2mpz and ammonia) bound to the metal atom (M).

The long-wave edge of the fundamental absorption band of β-Ga₂O₃ thin films obtained by the method of radio-frequency ion-plasma sputtering is studied. It is shown that during annealing offilms in oxygen, argon, and hydrogen, the edge of the interzone absorption is well approximated by the Urbach empirical rule. To analyze the experimental results, the model of a heavily doped or defective semiconductor in the quasiclassical approximation was used. The use of this model allowed determining the radius of the basic electronic state a, the shielding radius rs, and the root-mean-square potential А.

High-purity fused silica has been implanted with 60-keV helium ions at the fluence of 1.5 • 10¹⁷ cm^-2. The effects of helium-ion implantation on optical properties of silica samples before and after helium implantation have been investigated by infrared (IR), photoluminescence (PL), and ultraviolet-visible (UV-vis) spectrophotometer. After helium-ion implantation, X-ray photoelectron spectroscopy (XPS) results indicate that Si 2p peak is shifted to higher binding energy. An obvious PL band at 500 nm is observed, and the PL intensity is significantly decreased. However, the intensity of IR and optical absorption is increased greatly by ion implantation. A mechanism for the effects of helium implantation on optical properties of fused silica is discussed.

The process of spin-selective quenching of a triplet (T) exciton by a fixed spin doublet (D) center in an organic semiconductor nanoparticle (anthracene, tetracene, MEH-PPV) was studied. Random walks of the T-exciton in a spherical nanovolume of a crystal or polymer globule were modeled on the basis of solution of the Neumann boundary diffusion condition. Time dependences of the non-selective on spin quenching rate of T-excitations for different values of geometric and diffusion parameters were calculated. The account of the spin dynamics of T-D-pair reagents allowed calculating magnetic field effects of T-D-quenching rate, which showed a strong influence of the nanoparticles size and initial position of the T-exciton and doublet sink on the absolute value of the effect. The obtained radial dependences of the magnetic field modulation of the quenching efficiency can be approximated by a superposition of two exponents.

The effect of the interpulse interval and the number of doubled laser pulses on the targeted formation ofthe component and charge composition of the laser plasma under the influence of doubled laser pulses on a target made of AD1 aluminum alloy (LSS-1 spectrometer) was studied. It is shown that when using he interpulse interval of 7-16 ps, the concentration of Al ions and the products of their interaction with oxygen and nitrogen in the air increases by several orders in comparison with the zero interval. The highest intensity of the bands of AlO suboxide and AlN molecules is observed at 40-50 sequential double pulses in a series. With an increase in the number of pulses in a series the intensity of the bands decreases that is connected with worsening of the interaction of Al atoms and ions with air molecules and atoms at the output from the micro nozzle with a change in the depth and shape of the microchannel. The temperature in the region of the plasma with the maximum content of Al III of ~ 22000-30000 K was estimated. To determine the temperature in the region of AlO formation, the ratio of the intensities of the AlO bands at 486.9/484.12 nm was used. An expression is obtained for determining the temperature of the region corresponding to the maxima of AlO formation. The established temperature range of4700-7000 K is slightly higher than the optimal dissociation temperature for AlO (4400 K). To obtain Al aerosols and products formed during the interaction of aluminum ions with oxygen and nitrogen in the air, a closed glass cell was used, where an aluminum target was placed. The size of the primary particles of aluminum oxide Al₂O₃ obtained at pulse energy of 53 mJ, estimated using high-resolution electron microscopy, is mainly 30-40 nm. The particles are assembled in agglomerates. The possibility of practical obtaining of activated Al₂O₃ nanopowders by irradiating the target with successive series of 50 double pulses per point for 10 min in a closed bottle is considered. Using Raman spectroscopy, the possibility of obtaining active forms of aluminum oxides and their interaction products with oxygen and nitrogen of air in a laser plasma, deposited on a glass surface in a closed cell is shown.

By the method of high-frequency repetitively pulsed f ~ 10-15 kHz laser action with a wavelength l = 1.064 fim and a power density q = 150 MW/cm² on zinc oxide ceramics doped with manganese oxide at a pressure in the vacuum chamber p = 2.7 Pa there were obtained nanostructured thin films on a silicon substrate. The surface morphology and the elemental composition of the obtained films were studied using atomic force microscopy; scanning electron microscopy, and X-ray spectral microanalysis. The features of the transmission spectra in visible, near and middle IR regions are revealed. The analysis of the electrophysical properties of the ZnO+2% MnO₂/Si heterostructure was carried out.

The values of electron concentrations and electron energy distribution functions in a short discharge gap between a rectangular hollow cathode and a mesh anode were obtained by the single probe method. It was established that the distributions of electrons are not Maxwell ones with an excess of high-energy electrons, the proportion of which decreases with a distance from the cathode.

A study of the component composition ofplasma jets generated by a dielectric barrier discharge in helium and air at atmospheric pressure was carried out by the methods of emission and absorption spectroscopy. The concentration of the main bactericidal component of the air plasma jet (ozone) was determined using both IR and UV absorption spectroscopy that increases the reliability of measurements. When studying an effect ofplasma jets on Staphylococcus aureus bacteria it was established that an air jet has a better inactivating effect compared to a helium one.

An absorption spectroscopy method is proposed for estimating hydroxyl concentration behind the reflected shock wave front without lasers and high-resolution spectrometers. The scheme of the method realization is shown, and the possibility of its usage in experiments with shock tubes is demonstrated. Temporal profiles of hydroxyl concentration are obtained in the induction period of self-ignition of a stoichiometric hydrogen-air mixture behind the reflected shock wave front.

The emission spectra of argon behind the front of a strong shock wave are studied in the range of shock wave velocities of 4.6-8.3 km/s and pressures before a wave front of 0.25-5.00 Torr are presented. Time-integrated sweeps of radiation in a wide spectral range from ultraviolet to infrared (190—1100 nm) as well as time dependences of the intensity of argon radiation at wavelengths of 420, 532.8, and 740 nm are obtained. Three characteristic stages of temporal evolution of line emission are defined. The dependence of the duration of the emission of lines and its intensity on the initial pressure of gas and velocity of shock wave is established. Data are obtained on intensity of background radiation, which can be used to separate intensity of certain lines of argon atom from the total radiation.

The excitation of atoms (molecules) of a rarefied gas by stationary broadband optical radiation in a thin cell, the inner thickness of which is many times smaller than its transverse size, is studied theoretically. The features of optical pumping and transit-time relaxation of atomic particles in such cells open new possibilities for ultra-high resolution spectroscopy. The conditions are analyzed under which narrow high-contrast sub-Doppler fluorescence resonances arise at the central frequencies of spontaneous transitions from optically excited atomic (molecular) quantum levels.

As a type of water reducer, polycarboxylate superplasticizers (PCEs) has been widely used in the concrete industry. The concentration and molecule weight of PCEs have a profound impact on the performance of fresh concrete. Based on ¹H low-field nuclear magnetic resonance (NMR) spectroscopy, this paper developed a novel method for the determination of the concentration and characterization of the molecule weight of PCEs. Five types of PCEs with various ether to acid ratios (3:1 to 5:1) and functional groups were syn-thetized in laboratory conditions, and their molecular structures were characterized by size exclusion chromatography. PCE solutions with concentrations from 0 to 40% were measured using the Carr-Purcell-Meiboom-Gill sequence by ¹Н low-field NMR. The results showed that the T₂ value of the main peak has a linear relation with the PCE concentration. The signal intensity of peaks whose T₂ values are smaller than 10 ms of the PCE solutions with a concentration of 20% is linearly correlated to the molecule weight of PCEs.

Novel tellurium(IV), tantalum(V), selenium(IV), and niobium(V) urate complexes were prepared with molar ratios 1:1 and 2:1 (metal:ligand). The uric acid (H₄UA) ligand was reacted with TeCU, TaCf, SeCl₄, and NbCf metal chlorides in the presence of NaOH to yield mononuclear and binuclear complexes. The mononuclear tellurium (IV) and tantalum(V) complexes formulas [Te(H₃UA)(H₂O)₃(Cl)]-2Cl-2H₂O (I) and [Ta(H₃UA)(H₂O)2(Cl)₂]-2Cl-₄H₂O (II), as well as binuclear selenium(IV) and niobium(V) complexes [Se₂(H₂UA)(Cl)₄] 2Cl 4H₂O (III) and [Nb₂(H₂UA)(Cl)s]-3H₂O (IV), were obtained in the presence of NaOH at pH 8-9. The metal complexes were characterized by elemental analyses, FTIR, ¹H-NMR, electronic, conductivity, and thermal analyses. In the case of mononuclear complexes, the coordinating sites are the pyrimidine carbonyl oxygen atom of C(6)=O group and imidazole nitrogen of deprotonated N(7)-H. In addition to these coordinating sites, the pyrimidine carbonyl oxygen atom of C(2)=O and pyrimidine nitrogen of deprotonated N(3)-H are involved in coordination in binuclear complexes. The metal urate complexes exhibited six-coordinate geometries, while the binuclear selenium is four-coordinate. The antibacterial and anticancer activities of the urate complexes were investigated. No antibacterial activity was observed in any treatments, except for gram-negative Klebsiella, which showed a slight effect. The metal complexes showed high proportions of cell viability percentage after treatment in both colorectal adenocarcinoma (Caco-2) and breast cancer (MCF-7) cell lines using the neutral red uptake assay.

The speciation of extracted chromium from ZSM-5 into an ionic liquid (IL) was studied using X-ray absorption near-edge structure (XANES) spectroscopy. The main adsorbed chromium species in ZSM-5 were Cr(VI)-HA (Cr(VI) chelated with humic acids (HAs)) (57%), Cr(VI)_ads (Cr(VI) adsorbed on ZSM-5) (33%), and Cr(III)-HA (Cr(III) chelated with HA) (10%). In this work, l-butyl-3-methylimidazolium chloride ([C₄mim]Cl), was used as the IL to extract the chromium compounds from ZSM-5. Experimentally, approximately 75% of the chromium compounds were extracted within 30 min at 343 K. Combining the chromium extraction efficiency and component fitting results of the XANES spectra, almost all of Cr(VI)-HA was extracted into [C₄mim]Cl. Following extraction, 34.5% of the Cr(VI) compounds were reduced to form Cr(III)-HA and Cr(III) ions. The Cr-O bond distance of Cr compounds was 1.69 A in [C₄mim]Cl as shown by X-ray absorption fine structure (EXAFS) spectroscopy. ¹H nuclear magnetic resonance (NMR) showed that the reduction and extraction of Cr(VI) compounds were affected by [C₄mim]⁺. The non-extractable chromium species in ZSM-5 were Cr(VI)_ads (9%), Cr(III)-HA (10.8%), and Cr(III)_ads (5.2%). The fraction of Cr(VI) was decreased greatly because of the use of [C4mim]Cl as the extractant.

The capabilities offilament-induced breakdown spectroscopy for the analysis of the elemental composition of water aerosols were estimated. The diameter of water aerosol droplets in the atmosphere was 0.8-2.0 pm. The emission lines of the chemical elements were excited by filamentation offemtosecond laser pulses (60 fs, 800 nm, 4.4 mJ) in the weak focusing mode by a lens with a focal length of 500 mm. The obtained limits of detection for Al (396.15 nm), Ba (553.35 nm), Ca (422.67 nm), Mg (285.21 nm), Na (588.99 nm), and Mn (403.08 nm) in a water aerosol were 12.1, 41.7, 10.0, 7.3, 0.7, and 32.2 mg/L, respectively.

There have been severe challenges in the security inspection of controlled hazardous liquids in public places in recent years. To further meet the practical requirements of the front line of security inspection, we designed and developed a hazardous liquid detector on the basis of the fusion of Raman spectroscopy, dielectric constant, and heat conduction. The design ideas and methods for the whole system, as well as its hardware and software platforms, are expounded emphatically. Several inflammable and explosive hazardous liquids, including gasoline, methanol, acetonitrile, and toluene, as well as water, were selected as samples and sealed in transparent and opaque containers to test the performance of the instrument. As shown by the experimental results, the three subsystems can quickly and non-destructively detect the corresponding samples without false positives or false negatives. The instrument has various detection functions that overcome the single technical defects and has broad application prospects.

Ihe realization of logical operations for images using an accumulated echo hologram in the presence of external spatially inhomogeneous electric fields is considered. It is shown that the photon echo locking effect allows controlling the type of logical operations (from uniting the sets to their symmetric difference and superposition) by varying the values of gradients of external spatially inhomogeneous electric fields.

We propose a method of the sum decomposition for Gaussian functions which allows expanding of the experimental photoluminescence spectrum into individual Gaussian emission bands. The decomposition process is carried out on the basis of a single experimental measurement. Meanwhile, the calculation of the Gaussian parameters (amplitude, maximum location, and half-width of the spectrum) is performed using three experimental points. The method was tested in the analysis of the photoluminescence spectra of ZnS:Mn crystals where individual emission bands were revealed by the proposed method as well as by the Alentsev-Fock and derivative spectroscopy methods.

We describe the design of an automated laboratory goniophotometer CHERRY (Chlorophyll Estimation and Reflectance Registration sYstem) intended for measuring the spectral reflectance coefficients of coniferous needles in the spectral range 400-2500 nm and the quantitative analysis of the content of colored pigments in needles in the spectral range 400-700 nm. The CHERRY goniophotometer permits to carry out two types of measurements: goniometric ones, in which the spectral reflectance is measured from the test sample in the vertical direction, as well as photometric ones, in which the transmittance of the direct radiation passed through a cuvette with a pigment solution is measured. The spectral reflectance measurements of spruce needles (Picea abies) in the spectral range 400-700 nm showed differences up to 15 % by employing extended or quasi-parallel sources. The vegetation index Vog2 for healthy needles is varied from -0.45 to -0.34 for different types of the sample location and from -0.42 to -0.39 for different orientations of the polarizer for the selected way of placing the sample. A relative deviation of the measured spectral reflectance in the spectral range 470-770 nm up to 5 % for 2 hours of measurements confirms the influence of the lab radiation source on the spectral reflectance of the needles. Quantitative measurements show that the sample of healthy needles contains 30 % more of the studied pigments than the sample of needles from a tree in a state of stress.

We investigated the luminescence intensity of a Nd³⁺:Y3Al₃O₁₂ laser crystal excited by the radiation of a blue LED with λ » 454 нм, simulating the ultraviolet part of the solar spectrum, before and after using of a spectral converter based on the Ce³⁺: Y₃Al₃O₁₂ phosphor. It was found that while we used such a phosphor, the luminescence intensity of Nd³⁺: Y₃Al₃O₁₂ at λ » 1064 nm was approximately three times higher than without it. Thus, yttrium-aluminum garnet crystals doped with cerium ions are promising luminophores for the introduction in quanthrons of solar-pumped neodymium lasers for increasing their efficiency.

We proposed an algorithm for separating the overlapping spectral components using the Tikhonov weighted regularization method is proposed. The use of the weighting function allows one to significantly reduce the regularization parameters and separate closely spaced spectral lines. The problem of the appearance of spurious oscillations in a sparse solution is solved by an iterative algorithm for correcting the main matrix. To determine the regularization parameter that provides the maximum resolution of the method, the posterior minimum threshold algorithm is used. The use of the algorithm fundamentally improves the quality of spectra processing and increases the information content of the spectroscopic methods. The efficiency of the proposed algorithm is shown on examples of processing the model and experimental Moss-bauer spectra.

We have obtained and investigated new photosensitive polymeric film composites based on oligo-N-glyci-dylcarbazole oligomer with additives of azobenzene dyes, i.e. azobenzene derivatives with a glycidyl group in their structure. It was shown that the created composites exhibit photovoltaic properties when they are irradiated within the absorption range of the azobenzene dyes. The mechanism and features of the photovoltaic effect in the investigated film composites are discussed.

The present work aims to focus on the synthesis and spectral studies of the charge-transfer interaction between the nitro organic acceptors molecules [e.g., 2,4,6-trinitrophenol (PA), 4-nitrophenol (4-NP), 4-nitroacetophenone (4-NAP), and m-dinitrobenzene (m-DNB)] with triamterene (TM) drug donors, which have many applications in industry, biology, and chemistry. The CT complexes of PA and 4-NP are formed by the association of electron-deficient and electron-rich moieties, held together by the weak force of attraction through a hydrogen bond. These molecules have been explored through the FTIR and Raman spectroscopic techniques. The speculated 1:1 or 1:2 structures of the complexes [(TM)(PA)], [(TM)(4-NP)₂], [(TM)(4-NAP)₂], and [(TM)(m-DNB)₂] determined by microanalytical and theoretical analyses shows that the interaction occurs through a H₂N⁺–H···O⁻ (O----H)(O-H----NH₂) bond or by n-p* regarding 4-NAP and m-DNB complexes. The thermogravimetric technique was utilized to determine the thermostability of the synthesized charge-transfer complexes by making comparisons to their constituents. The computational study has been carried out on the studied molecule, which has the most stable conformer using density functional theory (DFT). A comparative study of electronic and vibrational spectroscopy has been done with that of experimental results. The experimentally obtained structure was compared with an optimized structure for various parameters, such as bond length, bond angles, oscillator strength, dipole moment, and molecular electrostatic potential is predicted theoretically. The energy band gap from HOMO-to-LUMO was theoretically estimated using (B3LYP/6-311 + +G(d,p) level) from frontier molecular orbital energies, and the outcome data are employed to characterize the chemical structures of the synthesized complexes based on molecular properties.

Fluorescent carbon nanodots were synthetized from garlic peels as optical nanobiosensors for an anti-leishmaniotic stibogluconate drug. The characterization techniques for the synthetized carbon nanodots confirmed its thermal stability, nanosize in the range 2—14 nm, amorphous nature, and the presence of C—O functional groups. The optical sensor, based on the fluorescent nature of carbon nanodots, was developed for the drug nanobiosensor in dosage form and in human biological fluids. The drug was digested to release a pentavalent antimony cation that quenches the fluorescence intensity of carbon nanodots. The extraction method was performed through ion pairing with trinonylamine. The optical sensing was extended to the in vivo analysis of stibogluconate in real human plasma. The sensing of stibogluconate was found to be linear over the range 0.01-0.10 µg/mL with percentage recoveries of 99.25±1.86, and 99.624±1.33 in vials with spiked plasma and in spiked urine.

A microwave-assisted, chemoselective synthesis of novel antitumor and antimicrobial (3E)-5-hydroxy-1-isopropyl-3-[(5-methyl-2-thienyl)methylene]-5-phenylpyrrolidin-2-one has been achieved via the solvent-free one-pot reaction of (3E)-3-[(5-methyl-2-thienyl)methylene]-5-phenylfuran-2(3H)-one with isopropylamine. The product is obtained in significant purity and yield under ecofriendly reaction conditions. The microwave technique surpasses conventional thermal heating approaches by accelerating the reaction in a clean, ecofriendly manner that avoids the use of organic or toxic solvents. The structural formula of the product is confirmed by crystallographic and spectroscopic characterization. X-ray single crystal diffraction reveals that the compound crystallizes in an orthorhombic centrosymmetric crystal form, with unambiguous assignment of the E-configuration for the C3-Cthienyl bond. The synthesized molecules have two centers of chirality in the hydroxypyrrolidin-2-one ring: 1) the carbon atom attached to nitrogen, the hydroxyl group, and the phenyl ring; 2) the nitrogen atom attached to the carbonyl carbon R3 group, the chiral carbon in the ring, and the covalent bond bearing the lone pair of electrons. The molecular geometry is also optimized using density functional theory calculations, and the results obtained are in good agreement with the experimental data. Evaluation of the biological and medicinal activity of the compound affords similar results to the reference data in antitumor treatment of human colon and breast cells, which can be attributed to the presence of the hydroxyl group, the heterocyclic motifs, and sulfur. Calculation of the molecular electrostatic potential locates the most electrophilic site near the hydroxyl group attached to the heterocyclic ring, which is consistent with the bioactivity results. The frontier molecular orbitals are also determined, finding that the energy difference between highest occupied molecular orbital and lowest unoccupied molecular orbital is -0.15228 eV. A mechanism is proposed in which an intramolecular nucleophilic attack occurs on the carbonyl carbon by the lone pair of electrons on the nitrogen atom, leading to ring closure with proton transfer to oxygen and final formation of the hydroxyl group.

A sensitive and accurate stability-indicating spectrofluorimetric method was created and validated for the determination of Cefdinir (CEF), a third-generation cephalosporin drug, via its acid and alkali-induced degradation products. The drug was determined via its acid-induced degradation products at 408 nm using an excitation wavelength of 292 nm, and via its alkali-induced degradation products at 458 nm after excitation at 330 nm. Linearity was achieved in the ranges 0.7—7.0 and 0.03-0.30 µg/mL for the acid-induced and alkali-induced degradation products, respectively. The investigation of degradation pathways was achieved using IR and LC/MS/MS. The technique was also validated by the International Conference on Harmonization Guidelines. The proposed technique was effectively implemented with excellent accuracy and precision to determine CEF in bulk powder and pharmaceutical dosage forms. The final results obtained by the application of the spectrofluorimetric method excellently agreed with the reported HPLC method.

A UV-Vis spectrophotometry method was developed for the determination of metoclopramide hydrochloride in pure and several pharmaceutical preparations, such as Permosan tablets, Meclodin syrups, and Plasil ampoules. The method is based on the diazotization reaction of metoclopramide hydrochloride with sodium nitrate and hydrochloric acid to yield the diazonium salt, which is then reacted with 3,5-dimethyl phenol in the presence of sodium hydroxide to form a yellow azo dye. Calibration curves were linear in the range from 0.3 to 6.5 µg/mL, with a correlation coefficient of 0.9993. The limits of detection and quantification were determined and found to be 0.18 and 0.61 µg/mL, respectively. Accuracy and precision were also determined by calculating the relative error, relative standard deviation, and recoveries. No interference was found from additive substances in pharmaceutical preparations. The proposed method has been successfully applied to determine metoclopramide hydrochloride concentrations in different pharmaceutical formulation samples.

Hepatitis infections represent a major health concern worldwide. Numerous computer-aided approaches have been devised for the early detection of hepatitis. In this study, we propose a method for the analysis and classification of cases of hepatitis-B virus (HBV), hepatitis-C virus (HCV), and healthy subjects using Raman spectroscopy and a multi-scale convolutional neural network (MSCNN). In particular, serum samples of HBV-infected patients (435 cases), HCV-infected patients (374 cases), and healthy persons (499 cases) are analyzed via Raman spectroscopy. The differences between Raman peaks in the measured serum spectra indicate specific biomolecular differences among the three classes. The dimensionality of the spectral data is reduced through principal component analysis. Subsequently, features are extracted, and then feature normalization is applied. Next, the extracted features are used to train different classifiers, namely MSCNN, a single-scale convolutional neural network, and other traditional classifiers. Among these classifiers, the MSCNN model achieved the best outcomes with a precision of 98.89%, sensitivity of 97.44%, specificity of94.54%, and accuracy of94.92%. Overall, the results demonstrate that Raman spectral analysis and MSCNN can be effectively utilized for rapid screening of hepatitis B and C cases.

A novel tridentate bisoxime chemosensor HL has been developed as a two-in-one platform for colorimetric recognition of Cu²⁺ (from blue to green), and fluorescent recognition of Cu²⁺ fluorescence quenching) and Zn²⁺ (fluorescence enhancement) in aqueous solution (CH₃OH/H₂O, 9:1, v/v). The UV-Vis and fluorescent spectra, IR, NMR, and density functional theory (DFT) calculations indicate that the recognition mechanism for quenching the fluorescence of the HL sensor for Cu²⁺ is a photoinduced electron transfer process (PET) between the recognition group (phenolic hydroxyl group and Schiff-base group) of the sensor and the signal reporter group (benzene ring), and the enhanced fluorescence recognition mechanism of the HL sensor for Zn²⁺ is of its hindered PET process.

A compact desktop near-infrared spectrometer with near-infrared spectrum acquisition software was developed based on fixed grating type fiber optic spectrometer with MEMS technology. The light source stability, baseline stability, instrument signal-to-noise ratio, and dark current drift are four important indicators for the performance test and evaluation of the spectral system. The test results show that the light source reaches a stable state after being warmed up for 2 s. The standard deviation of 100 %T line of1200-1550 nm instrument is less than 0.0003, and the signal-to-noise ratio is 3000:1. The dark current relative standard deviation fluctuates between 0.0019 and 0.0035. Based on 88 samples of the crushed material of lumber for wood cellulose and lignin contents, the quantitative calibration model was established using multiple scatter correction spectra pretreatment method set up after the correction model of cellulose and lignin. Root mean square errors of calibration set of cellulose and lignin are 0.6096 and 0.9572%, respectively. Root mean square errors of prediction set of cellulose and lignin are 1.2884 and 1.7712% respectively. The experimental results show that the developed small NIR spectrometer has a stable working state, and the prediction results for cellulose and lignin content based on the calibration model for powdery wood samples verify that the small NIR spectrometer has a high detection accuracy and can be used in the rapid detection of common materials.