Surface Of Charge Research Articles

Mass transfer and formation of micro-inclusions in Ti-sapphire grown by the HDC method

The formation mechanism of micro-inclusions in titanium-sapphire crystals grown with the method of horizontal directional crystallization in a gas atmosphere was studied. It has been shown that the micro-inclusions of metallic tungsten and/or molybdenum are mainly formed at the surface of the unmelted charge. The thermodynamic analysis of the possible reactions of Mo and W among the charge components, the products of charge dissociation, and the components of the technological atmosphere was carried out. It is shown that CO2, CO, H2O, as well as suboxides of Al and Ti, can serve both as oxidizers of Mo and W and as reducing agents of their condensed oxides. The mechanism of mass transfer within which gaseous Mo and W oxides are reduced on the charge surface to form metal micro-particles was proposed. These particles further fall into the melt and then are transported with convective flows to the crystallization front and embedded into the crystal as micro-inclusions.

Achieving overall rejection of pharmaceuticals and personal care products of different polarities by controlling interlayer charging environment of graphene oxide membrane using carbon quantum dots

To realize overall rejection of numerous pharmaceuticals and personal care products (PPCPs) with varieties in hydrophilicity (dissolubility giving either negative or positive charges and non-dissolubility) and hydrophobicity, a diverse interlayer charging environment was controlled by intercalating two-dimensional carbon quantum dot (CQD)-like nanoparticles into graphene oxide membrane (GOM). It was found that ethylenediamine-added sucrose-derived CQD with a positively charged surface in aqueous solution is appropriate for such a purpose because of the strong electrostatic attraction by the graphene oxide (GO) surface of opposite charge. The CQD contains plenty of pyridine groups of stronger basicity and pyrrole groups of weaker basicity, which contribute majorly to anchoring the CQD onto GO surface and to donating positive charges in GOM interlayer, respectively. This unique membrane design strategy allows coexisting of both negatively and positively charged groups in a slightly expanded hydrophilic interlayer space of GOM. As the result, not only rejections were promoted for the negatively dissociative PPCPs (from 77 % to all more than 86%) and neutral PPCPs (from 25 % to all more than 56%) but also rejections of the positively dissociative PPCPs became remarkable (from null to all more than 56%). The research result provides a promising methodology of changing chemical environment of a simpler membrane material other than nanofiltration or reverse osmosis to achieve an all-together rejecting effect toward PPCPs of various polarities.

Rapid detection for the surface and hidden crack of solid propellant motor charge using laser arrays scanning thermography (LAsST)

Laser arrays scanning thermography (LAsST) was introduced to detect the surface and hidden cracks of solid propellant motor charge. A series of simulated surface cracks of solid propellant charge was prepared and detected by LAsST. The thermal-wave response signal is reconstructed by truncation pseudo-static matrix reconstruction (TC-PSMR), and then, the thermal image sequence similar to the impulse response is reconstructed. The principle of characteristic extraction algorithms [such as Fast Fourier transform (FFT), principal component analysis (PCA), and partial least squares regression (PLSR)] are introduced and employed to obtain the feature images from the thermal-wave response. The morphological matrix is used to denoise the processed image. The experimental results demonstrated that the defects of the PLSR image and FFT phase image are more obvious, and the image noise after morphological matrix processing is significantly reduced. Meanwhile, the LAsST approach can enable rapid detection for the surface and hidden cracks of solid propellant motor charge.

Brownian loops and the central charge of a Liouville random surface

We explore the geometric meaning of the so-called zeta-regularized determinant of the Laplace–Beltrami operator on a compact surface, with or without boundary. We relate the (−c/2)th power of the determinant of the Laplacian to the appropriately regularized partition function of a Brownian loop soup of intensity c on the surface. This means that, in a certain sense, decorating a random surface by a Brownian loop soup of intensity c corresponds to weighting the law of the surface by the (−c/2)th power of the determinant of the Laplacian. Next, we introduce a method of regularizing a Liouville quantum gravity (LQG) surface (with some matter central charge parameter c) to produce a smooth surface. And we show that weighting the law of this random surface by the (−c′/2)th power of the Laplacian determinant has precisely the effect of changing the matter central charge from c to c+c′. Taken together with the earlier results, this provides a way of interpreting an LQG surface of matter central charge c as a pure LQG surface decorated by a Brownian loop soup of intensity c. Building on this idea, we present several open problems about random planar maps and their continuum analogs. Although the original construction of LQG is well defined only for c≤1, some of the constructions and questions also make sense when c>1.

Сопоставление численных моделей динамики электрически заряженных газовзвесей с массовой и поверхностной плотностями зарядов для различных дисперсностей частиц

The purpose of the study was to mathematically model the dynamics of inhomogeneous electrically charged media, such as that of gas suspensions, i.e., solid particles suspended in a gas. The mathematical model implemented a continuum approach to modeling the dynamics of inhomogeneous media, which implies taking into account intercomponent heat transfer and momentum exchange. The carrier medium was described as a viscous, compressible, heat-conducting gas, the equations of the model were supplemented with initial and boundary conditions, and the system of the equations was integrated by an explicit finite-difference method. To obtain a monotonic grid function, a nonlinear scheme for correcting the numerical solution was used. The mathematical model was supplemented with the Poisson equation describing the electric field, which is formed by electrically charged disperse inclusions. The Poisson equation was integrated by finite-difference methods on a gas-dynamic grid. The flow of a gas suspension caused by the motion of dispersed particles under the action of the Coulomb force was studied numerically. Flows of gas suspensions with surface and mass densities of electric charge were modeled. For the surface charge density model, the Coulomb force acting on the unit mass of the gas suspension increases with a decrease in the dispersion of particles. For the mass charge density, the dispersion of particles does not affect the specific Coulomb force acting on the particles. The intensity of the gas suspension flow increases with decreasing particle size, both for the mass and surface models of charge density. For the surface charge density model, as the particle size decreases, the intensity of the gas pressure drop in the emerging gas suspension flow increases more than when modeling the gas suspension dynamics with a mass distribution of the electric charge density

Engineered defect-rich TiO2/g-C3N4 heterojunction: A visible light-driven photocatalyst for efficient degradation of phenolic wastewater

Photocatalytic technology has been considered as an effective way for pollutants removal. Considering that the nature of the photodegradation of pollutants is the free radical reaction on the surface of the catalyst, promoting the generation of free radicals is a direct and effective way to facilitate the mineralization of pollutants. Unfortunately, the shortcomings strongly limit its photocatalytic activity such as insufficient sunlight utilization, small catalytic surface and rapid recombination of charge. Here, a heterostructure of defect-rich TiO2 nanoparticles anchored in g-C3N4 was fabricated by a synchronous compound process. This heterostructure (4TiO2/g-C3N4) exhibits an enhanced visible light absorption due to its narrow band gap energy of 2.27 eV. Therefore, it possesses an outstanding photocatalytic activity for the degradation of phenol (1.63 × 102 μmol g−1 h−1), p-nitrophenol (1.15 × 102 μmol g−1 h−1), o-cresol (1.43 × 102 μmol g−1 h−1) and p-cresol (1.45 × 102 μmol g−1 h−1). The calculated quantum yields of 4TiO2/CN for pollutants degradation are 1.29 × 10−6 for phenol, 9.10 × 10−7 for p-nitrophenol, 1.14 × 10−6 for o-cresol and 1.15 × 10−6 for p-cresol, respectively. By utilizing the periodic topology of MOFs, this work provides an improved approach for constructing TiO2/g-C3N4 heterojunctions with enhanced degradation of robust organic pollutants.

Formation of converging cylindrical detonation front

Purpose. To develop a laser method for initiating a converging cylindrical front of a detonation wave and a method for calculating the kinematic parameters of the cylindrical shell walls, accelerated by the pressure of the detonation products of an external explosive charge. Methodology. An experimental technology for the manufacture of a photosensitive explosive composite and an experimental technique for igniting the surface of its layer with an extended laser beam without the use of a fiber-optic cable are used. The results of simulation modeling the Monte Carlo method were used to study the effect of illumination on the process of ignition of explosives by laser pulsed radiation. For the selected type of photosensitive explosive composite, its explosive and optical characteristics, the distance from the surface of the explosive charge to the lens scattering the laser beam, and taking into account the total area of the expanded beam, the regularities of the distribution of the radiation energy density over the vertical and horizontal sections of the laser beam were studied. Findings. The analysis of the scientific and technical level of methods of shock-wave processing of materials in the region of ultrahigh pressures from the point of view of the fundamental value of the cumulation of energy in the waves of a converging cylindrical detonation and shock front is carried out. Physicomathematical modeling was carried out and the regularities of pressure increase in the wave front were established in the process of approaching the shell walls to the axis. The scientific results of modeling converging cylindrical shells under the influence of the pressure of the explosion products have been analyzed. A method for laser initiation of a converging cylindrical front of a detonation wave has been developed, and a method for calculating the kinematic parameters of the converging walls of a cylindrical shell has been proposed. Originality. A technique has been developed for determining the energy characteristics of an expanded laser beam, calculating the laser radiation energy required to initiate detonation simultaneously on the entire lateral cylindrical surface of a photosensitive explosive composite. The idea of technical implementation of the cumulation of converging cylindrical detonation and shock waves was developed further. A technique has been developed for the numerical determination of the change in the internal average compression rate of the shell during the movement of its walls towards the axis for various ratios of its external radius to the wall thickness and taking into account the increase in pressure in the converging detonation front. Practical value. For the first time, a method for laser initiation of a converging cylindrical front of a detonation wave was developed and a device was tested that forms a converging cylindrical front of a detonation wave and a corresponding shock front in the material under study by the impact of a metal shell converging to the axis. The core of the device is a laser explosive initiation system that uses light-sensitive explosive composites to initiate an explosive charge.

Cathode-Electrolyte Interphase in Lithium Batteries Revealed by Cryogenic Electron Microscopy

Summary Cathode electrolyte interphase (CEI), the intimate coating layer formed on the positive electrode, has been thought to be critical. However, many aspects of CEI remain unclear. This originates from the lack of effective tools to characterize structural and chemical properties of these sensitive interphases at nanoscale. Here, we develop a protocol to preserve the native state and directly visualize the interface on the positive electrode using cryogenic electron microscopy. We find that under normal operation conditions, there does not exist an intimate coating layer at the single-particle level in carbonate-based electrolyte. However, upon brief external electrical shorting, a solid-electrolyte interphase, which usually forms on anodes, could form on cathodes and be electrochemically converted into a stable, conformal CEI in situ. The conformal CEI helps improve Coulombic efficiency and overall capacity retention of the battery. This generates a different perspective of CEI in commercial carbonate-based electrolytes than previously understood.

Optimal Sizing, Selection, and Techno-Economic Analysis of Battery Storage for PV/BG-based Hybrid Rural Electrification System

The focus of the paper is on the renewable energy-based rural electrification system. Two concepts have been used in finding solutions to the issues related to this micro-grid system. The first is the best fitted model of hybrid configuration system, which utilizes village-owned resources, such as abundant biomass and solar irradiation. The second is that observed improved performance in terms of system sizing, techno-economic performance, and environmental stability of the hybrid model over different power storage backup media. The practical aspects and suggestion over the hybrid village electrification system have been presented through a case study of Korkadu village, Puducherry state, India. A comparative analysis of the hybrid model has been made with different power storage backup systems, namely the solid-state battery (lead acid-ASM battery, Li-ion-ASM battery) and flow battery (Redflow ZBM2 battery) arrangement. The result revealed hybrid rural electrification system with LI battery as the most favourable choice of the electrification system to the village, considering that its economic factor includes the total net present cost, cost of energy are found to be lowest. The technical parameters of power production capacity surface and battery state of charge were observed to be optimum with reduction in the environmental pollution parameter (GHS emission) value.

Numerical simulation of the metal bridge foil explosion plasma ignition of B/KNO3

Plasma ignition technology utilizes the plasma generated by an electrical explosion of a metal bridge foil under the action of a pulsed current to ignite an ignition charge. The plasma generated by the electrical explosion of a metal array bridge foil can be superimposed and converged to improve the energy utilization efficiency of the electrical explosion process and enhance the ignition capability. A multiphase-flow numerical calculation model of the electrical explosion plasma-ignition process was established, and numerical simulations were carried out. In the simulations, a plasma state equation that considers changes in the number of particles and the Coulomb interactions between particles was employed, and the Arrhenius law, which describes the exothermic heat of the ignition charge, was used. The ignition mechanism of the ignition charge under the action of plasma was analyzed, and the influences of the bridge foil structural characteristics on the ignition effect of the ignition charge were examined. The results of the calculations show that the plasma region, the plasma jet, and the pressure shock wave do not reach the ignition surface of the ignition charge when it is ignited. The ignition of the ignition charge is due to the thermal radiation process of the plasma. Compared to a single bridge foil, a metal array bridge foil has a larger plasma radiation region after an electrical explosion, and the ignition charge absorbs more energy from the plasma radiation, which is more favorable for ignition.

Control of metal heat treatment process in a furnace using a diagnostic system based on batch heat capacity

A method for determining the time at which ingots heated in a furnace achieve a predetermined thermal state is proposed, based on a real-time determination of the average heat flux density on the surface of a metal charge and the corresponding heat content increase relative to the initial state. An appropriate heating control algorithm is described, and the calculation results are presented for the example of a bogie hearth furnace.

Flash Radiographic Study of Detonation Propagation in Semi-Ring Charges of TATB

Flash radiography was used to study the propagation of detonation in semi-ring charges of plastic bonded TATB with an inner steel shell when initiating normal detonation along a line on the outer surface of the charge. The shape of the detonation wave front at different times was determined. The shape of the front was found to be influenced by a layer of RDX based plastic bonded explosive placed on the surface of the main charge and having a detonation velocity ≈10% higher than that of TATB. It is shown that the position and shape of the detonation wave front in a cylindrical TATB charge is not described by the laws of geometric optics (Huygens principle) due to the features of detonation initiation in the initial section and the presence of the steel shell.

SIGNIFICANCE OF SOIL DEVELOMENT AND IRON OXIDES CONTENT ON PROPERTIIES OF PERMENANT CHARGE ON CLAY SURFACES IN SOME SELECTED SOILS FROM NORTHERN IRAQ

The study was conducted on nine clay samples collected from three different soils of northern Iraq (Mukhmour, Shikhan and Zakho) which varied in climatic conditions (precipitations and temperatures).Permanent surface charge on clay surfaces was measured through adsorption of lithium chloride experience before and after removing iron oxides. Results showed that the highest values of permanent negative charge on clay surfaces before removing iron oxides was found in Mukhmour soil with average 34.5 C.mol. kg-1. clay, while the lowest values appeared in clay fraction of Zakho soil (18.1 C.mol. kg-1. clay), but in Shikhan soil,the negative charge values was at average of (20.0 C.mol. kg-1 clay). The highest stability of negative surface charge was found at pH between values (3-5). The distribution of negative charges within soil profiles showed an increase in values with depth and in all studied soils. Results also reveals very low positive surface charge compared with negative surface charge. However, the results of the lithium chloride adsorption experiment have indicated that the removal of iron oxides from clay fraction had a clear effect on increasing in the values of negative surface charge in all study soils.The rates of increase associated mainly with the iron oxides content of the clay fractions but the impact of removing iron oxides on the values of positive surface charge were minor and had no clear behavior. From the above study it can be concluded that the variations in the values of surface of clay surface charge clearly reflects the levels of weathering and the degrees of soil development.

Liposomal formulations of carboplatin injected by convection-enhanced delivery increases the median survival time of F98 glioma bearing rats

BackgroundEffectiveness of chemotherapy for treating glioblastoma (GBM) brain tumors is hampered by the blood–brain barrier which limits the entry into the brain of most drugs from the blood. To bypass this barrier, convection-enhanced delivery (CED) was proposed to directly inject drugs in tumor. However, the benefit of CED may be hampered when drugs diffuse outside the tumor to then induce neurotoxicity. Encapsulation of drugs into liposome aims at increasing tumor cells specificity and reduces neurotoxicity. However, the most appropriate liposomal formulation to inject drugs into brain tumor by CED still remains to be determined. In this study, four liposomal carboplatin formulations were prepared and tested in vitro on F98 glioma cells and in Fischer rats carrying F98 tumor implanted in the brain. Impact of pegylation on liposomal surface and relevance of positive or negative charge were assessed.ResultsThe cationic non-pegylated (L1) and pegylated (L2) liposomes greatly improved the toxicity of carboplatin in vitro compared to free carboplatin, whereas only a modest improvement and even a reduction of efficiency were measured with the anionic non-pegylated (L3) and the pegylated (L4) liposomes. Conversely, only the L4 liposome significantly increased the median survival time of Fisher rats implanted with the F98 tumor, compared to free carboplatin. Neurotoxicity assays performed with the empty L4′ liposome showed that the lipid components of L4 were not toxic. These results suggest that the positive charge on liposomes L1 and L2, which is known to promote binding to cell membrane, facilitates carboplatin accumulation in cancer cells explaining their higher efficacy in vitro. Conversely, negatively charged and pegylated liposome (L4) seems to diffuse over a larger distance in the tumor, and consequently significantly increased the median survival time of the animals.ConclusionsSelection of the best liposomal formulation based on in vitro studies or animal model can result in contradictory conclusions. The negatively charged and pegylated liposome (L4) which was the less efficient formulation in vitro showed the best therapeutic effect in animal model of GBM. These results support that relevant animal model of GBM must be considered to determine the optimal physicochemical properties of liposomal formulations.

Efficiency relationship between initiation of HNS-IV and nanosecond pulsed laser-driven flyer plates of layered structure

AbstractThree types of multilayer flyer energy conversion elements (MFECEs) through integrating different laser pulse absorption/ablation layer of nano-film materials into a laser-driven flyer plates between thermal barrier of alumina and transparent substrate have been investigated in this study. The relationships among the velocity of flyer plates, initiation performance of hexanitrostilbene (HNS-IV), and initiation energy were analyzed, comparing with single-layer Al flyer plate. The photonics Doppler velocimetry and James criterion were utilized in the experiments to characterize the velocity of flyer plates and shock initiation of laser-driven flyer detonator, respectively. The surface reflectivity measurements of the Al, C/Al and Mg/Al layers were performed using laser reflectivity. HNS-IV without initiation was analyzed by scanning electron microscope and energy dispersive spectrometer. Caused by aluminum/alumina/aluminum (Al/Al2O3/Al) flyer plate, the residual fragments were found in the pit on the surface of charge. The results obtained were shows that three types of multilayer flyer plates can initiate HNS-IV successfully under the lower laser pulse energy, although all four kinds of flyer plates have successfully initiated HNS-IV with laser pulse energy in the range of 53.80–166.80 mJ. Changing the ablation layer structure and adding thermal insulation layer to the multilayer flyer plates, reduces the shock initiation laser pulse energy of HNS-IV to 53.80 mJ. The laser-driven flyer detonator has significant advantages in providing safety and reliability, especially in a strong electromagnetic environment. The MFECEs of laser-driven flyer detonator exhibited a high level of integration and proved to have promoted laser-driven energy coupling rate, which can significantly be used to improve the performance of the laser-driven flyer detonator in military and civilian applications.

Electrochemical Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy: Bonding, Structure, and Ion-Pairing of the Positive Charge Bearing Pyridinium Ring Terminated Monolayer at Smooth Gold Electrode

Electrode potential effect on the molecular structure of adsorbed species at an interface is one of the most important issues in physical electrochemistry. In this study, shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) was used to probe the electrochemical potential effect on bonding with surface, ion-pairing, and molecular structure of a positive charge bearing self-assembled monolayer formed from N-(6-mercapto)hexylpyridinium (MHP) at a smooth gold electrode in aqueous perchlorate solutions. In situ electrochemical SHINERS results show that the Au–S stretching frequency exhibits near linear blue-shift as the electrode potential was tuned to more positive values. The frequency tuning rate was found to be as high as 18.6 ± 0.9 cm–1/V. Analysis of ion-pairing at the interface revealed a decrease in intensity of the vibrational spectrum of electrostatically attracted perchlorate anions as the electrode potential shifts progressively to more negative values. Spectroscopic evidence for poten...

ESTUDO DO PERFIL TÉRMICO DE FORNOS DO TIPO "CAIPIRA" UTILIZADOS PELO SETOR DE CERÂMICA VERMELHA EM PARELHAS NA REGIÃO DO SERIDÓ, RN1

RESUMO Este trabalho teve como objetivo caracterizar o perfil térmico de fornos tipo "caipira" utilizados pelo setor de cerâmica vermelha em Parelhas, na região do Seridó, RN, visando propor intervenções estruturais que possam colaborar para aumentar a produtividade e qualidade dos produtos, otimizar o consumo de madeira e mitigar as perdas durante o processo de queima. O trabalho foi desenvolvido na Cerâmica Esperança, na cidade de Parelhas, RN. Foram realizados quatro tratamentos com três repetições, sendo a argila o parâmetro utilizado como referência para distinguir os tratamentos. Foram monitorados a quantidade da lenha, a qualidade da telha e o tempo de cada queima. Foram aferidas temperaturas em 15 pontos marcados na superfície da carga enfornada, em intervalos de 30 min a partir do pré-aquecimento até o final da queima, utilizando um pirômetro de mira a laser. Os resultados indicaram que a madeira utilizada como lenha apresentou densidade sem diferença significativa entre os tratamentos, umidade dentro dos padrões permitidos e consumo heterogêneo, enquanto a argila teve pouca retração linear quando submetida ao fogo e o forno, perfil térmico heterogêneo. O parâmetro do fio, que é utilizado como referência para o controle da queima, foi significativo, embora com oscilações diferenciadas, razão por que não deve ser o único critério para finalização do processo de queimas. A parte central do forno foi a área que atingiu maiores temperaturas de maneira homogênea, com maior concentração de produtos de primeira qualidade; a curva de temperatura ideal foi do tratamento 1, com uma média de 18,66% de produto de primeira qualidade, com temperatura de 100 °C a 400 °C.

Specific ion effects on the self-assembly of ionic surfactants: a molecular thermodynamic theory of micellization with dispersion forces.

The self-assembly of amphiphilic molecules is a key process in numerous biological and chemical systems. When salts are present, the formation and properties of molecular aggregates can be altered dramatically by the specific types of ions in the electrolyte solution. We present a molecular thermodynamic model for the micellization of ionic surfactants that incorporates quantum dispersion forces to account for specific ion effects explicitly through ionic polarizabilities and sizes. We assume that counterions are distributed in the diffuse region according to a modified Poisson-Boltzmann equation and can reach all the way to the micelle surface of charge. Stern layers of steric exclusion or distances of closest approach are not imposed externally; these are accounted for through the counterion radial distribution profiles due to the incorporation of dispersion potentials, resulting in a simple and straightforward treatment. There are no adjustable or fitted parameters in the model, which allows for a priori quantitative prediction of surfactant aggregation behavior based only on the initial composition of the system and the surfactant molecular structure. The theory is validated by accurately predicting the critical micelle concentration (CMC) for the well-studied sodium dodecyl sulfate (SDS) surfactant and its alkaline-counterion derivatives in mono- and divalent salts, as well as the molecular structure parameters of SDS micelles such as aggregation numbers and micelle surface potential.

Preparation of Biocompatible Carboxymethyl Chitosan Nanoparticles for Delivery of Antibiotic Drug

Objective. To prepare biocompatible ciprofloxacin-loaded carboxymethyl chitosan nanoparticles (CCC NPs) and evaluate their cell specificity as well as antibacterial activity against Escherichia coli in vitro. Methods. CCC NPs were prepared by ionic cross-linking method and optimized by using Box-Behnken response surface method (BBRSM). Zeta potential, drug encapsulation, and release of the obtained nanoparticles in vitro were thoroughly investigated. Minimum inhibitory concentration (MIC) and killing profiles of free or ciprofloxacin-loaded nanoparticles against Escherichia coli were documented. The cytotoicity of blank nanoparticles and cellular uptake of CCC NPs were also investigated. Results. The obtained particles were monodisperse nanospheres with an average hydrated diameter of 151 ± 5.67 nm and surface of charge −22.9 ± 2.21 mV. The MICs of free ciprofloxacin and CCC NPs were 0.16 and 0.08 μg/mL, respectively. Blank nanoparticles showed no obvious cell inhibition within 24 h, and noticeable phagocytosis effect was observed in the presence of CCC NPs. Conclusion. This study shows that CCC NPs have stronger antibacterial activity against Escherichia coli than the free ciprofloxacin because they can easily be uptaken by cells. The obtained CCC NPs have promising prospect in drug delivery field.

Enzyme Substrates Protective Encapsulation within Polymeric Microspheres

Determination of enzymes activity is an important task of analytical and biomedical oriented fluorimetry. Despite of a long track record of application, there is still some room for improvements in this field. In the case of hydrolases, spontaneous decomposition of substrate leads to substantial errors in determination of enzyme activity. An innovative and effective approach is proposed allowing protection of enzyme substrate within the lipophilic moiety of polyacrylate microspheres. It is shown that the introduction of substrate into microspheres is not only an effective method of prevention of unwanted spontaneous process, but also does not disturb the availability of substrate for enzymatic hydrolysis. The effect of presence of proteins in the sample on fluorimetric responses was studied. In contrary to previous studies related to application of lipophilic polymers in biomedical analysis, it is shown that the presence of bovine serum albumins enhances the sensitivity of fluorimetric determination. It is shown that this surprising effect is related to adsorption of proteins on the microspheres surface and change of surface charge of polymer.