Wyniki wyszukiwania - Biblioteka Nauki

1

NO2 optical fibre sensor based on porous glass probe

100%

Dorosz D. , Procyk B.

Molecular and Quantum Acoustics

|

2008

|

tom Vol. 29

65-72

EN

Nitrogen dioxide optical fibre sensor based on nanoporous glass probe was obtained. As a sensor probe glasses from the Na2O-B2O3-SiO2 system modified with TiO2 and ZrO2 and Al2O3 have been made. Porous glasses based on silica posses very good thermal and chemical durability, they are also transparent in the wide of spectrum range. It makes also possibility of use this kind of material as an optical sensor element, operating in hard working conditions. The presented design consists in the spectroscopic changes caused by the specific coloration reactions between NO2 and organic reagents placed in the nanopores. The presented different sensing reagents are compared and allow to achieve ppb NO2 level detection. High specific surface area (200 m2/g) and stable pores distribution in the size of obtained glasses assured good repeatability of the sensor.

2

The photoluminescent properties of CdS clusters of different size in porous glasses

80%

Rysiakiewicz-Pasek E. , Polańska J. , Gevelyuk S. A. , Doycho I. K. , Mak V. T. , Zhukov S. A.

Optica Applicata

|

2008

|

tom Vol. 38, nr 1

93-100

EN

CdS nanoclusters were formed in the porous glass matrix by sequential chemical deposition from liquid-vapor phase and their chemical content was investigated. The room temperature photoluminescence spectra of specimens excited with a 235 nm wavelength had typical narrow peaks at 400 nm. The peaks can be explained by quantum effects for charge carriers confined inside the small-size (radius of the order of several nanometers) clusters. At the same time the luminescence spectra of the same specimens, but excited with a xenon lamp at 77 K, had peaks at ~700 nm that approximately corresponded to the band gap of the crystalline CdS. The possibility of the crystallites existence follows from the size distribution of voids in the porous glass matrix and is confirmed by the X-ray spectra typical of the wurtzite structure. The peculiarities of the observed luminescence spectra are explained by the energetic diagram of CdS in the configurational space.

3

The influence of preparation technology on phase transitions in NaNO2 embedded into porous glass

80%

Rysiakiewicz-Pasek E. , Jagus P.

Optica Applicata

|

2008

|

tom Vol. 38, nr 1

101-107

EN

The dielectric properties of sodium nitrite embedded into porous glasses with the average pore diameter of 45 nm and 320 nm have been studied. The samples were obtained by immersion of empty porous glass into the melted NaNO2 and then they stayed there for 24 and 8 hours. The sequence of phase transitions (PT) from the paraelectric phase to the sinusoidal antiferroelectric phase and to the ferroelectric phase has been observed in these nanocomposite materials on cooling. It is shown that due to the size effect, the temperatures of these PTs are lower than in bulk NaNO2

4

Redukcja zanieczyszczeń węglowodorowych ze środowiska wodnego przy wykorzystaniu szkła porowatego

80%

Macuda J. , Procyk B. , Rogowska-Kwas R. , Zawisza L.

Wiertnictwo, Nafta, Gaz

|

2004

|

tom R. 21/1

239-245

PL

Substancje ropopochodne ze względu na swoje właściwości są bardzo szkodliwe dla środowiska, zwłaszcza gruntowo-wodnego. W przypadku wystąpienia awarii połączonej z niekontrolowanym wyciekiem do środowiska, część węglowodorów udaje się usunąć, ale zdecydowana większość infiltruje do gruntu, a następnie do wód podziemnych i powierzchniowych. Powodują one zmiany organoleptyczne wody, działają toksycznie na faunę i florę, kumulują się w tkankach organizmów żywych oraz stwarzają duże trudności przy uzdatnianiu wody. W artykule przedstawiono właściwości fizykochemiczne modyfikowanych szkieł porowatych z układu Na2O-B2O3-SiO3 oraz wyniki badań ich wykorzystania do usuwania węglowodorów ze środowiska wodnego. Na podstawie uzyskanej redukcji zanieczyszczeń w próbach laboratoryjnych można stwierdzić, że szkła porowate mogą być stosowane jako adsorbenty i wykorzystywane do likwidacji zanieczyszczeń węglowodorowych z wód podziemnych i powierzchniowych.

EN

Owing to their properties, oil products are very noxious for the environment, soil and water in particular. In the case of a break-down accompanied by an uncontrollable seepage to the environment, part of hydrocarbons can by removed, but most of them infiltrate the soil, ground- and surface waters. This results in organoleptic changes of water, toxication of flora and fauna and accumulation in the tissues of living organisms. Besides, such situations create serious problems with water treatment. Physicochemical properties of modified porous glasses Na2O-B2O3-SiO2 are presented and the results of their application to the removal of hydrocarbons from the water environment are discussed. It can be stated from the laboratory results of contamination reduction that porous glasses can be used as adsorbents for fighting hydrocarbon contaminations in ground- and surface waters.

5

Inverse gas chromatographic studies on porous glass

80%

Rueckriem M. , Hahn T. , Enke D.

Optica Applicata

|

2012

|

tom Vol. 42, nr 2

295-306

EN

Porous glass is a well suitable system for the exploration of new characterization techniques due to adjustable texture properties and the possibility to "tailor-made" the surface chemistry. In this study porous glass beads were utilized as model system for the evaluation of inverse gas chromatography (IGC). Mesoporous glass beads with 10 and 20 nm pore size and macroporous glass beads with 50 nm pore size were synthesized and modified by thermal treatment and chemical reaction with hexamethyldisilazane (HMDS), ethyl-, propyl-, butyl- and octyldimethylchlorosilane. The correlations between the textural properties and the dispersive surface energy were investigated by means of the IGC technique. Furthermore dependences between surface chemistry and surface energy were pointed out on the basis of IGC measurements.

6

Aggregation of dyes in porous glass

80%

Tyurin O. V. , Bercov Y. M. , Zhukov S. O. , Levitskaya T. F. , Gevelyuk S. A. , Doycho I. K. , Rysiakiewicz-Pasek E.

Optica Applicata

|

2010

|

tom Vol. 40, nr 2

311--321

EN

The research examines the interaction of dye molecules with their dimers (H aggregates) and the more complex formations (J aggregates) developing in porous glass. The use of porous glass when dealing with dye aggregation has resulted in obtaining photoluminescence dimers of the J aggregating dye, the formation of which is difficult under normal conditions. In addition, the porous glass matrix contributes to a substantial reduction in the interaction of photoexcited states of both a molecular and an aggregated dye, thus helping maximize the luminescence efficiency of porous glass-distributed dyes.

7

Porous glasses with sodium nitrite impregnations

80%

Rysiakiewicz-Pasek E. , Poprawski R. , Urbanowicz A. , Mączka M.

Optica Applicata

|

2005

|

tom Vol. 35, nr 4

769-774

EN

The properties of sodium nitrite introduced in porous glasses have been investigated. SEM graphs indicate existence of sodium nitrite inside glass pores. It has been shown that FTIR and Raman spectra are similar for bulk sodium nitrite and sodium nitrite embedded into porous glass. The nature of FTIR and Raman bands has been determined. The size-effect of sodium nitride introduced into porous glass was observed on the basis of dielectric measurements.

8

Application of modified porous glasses Al2O3 for hydrocarbon contamination sorption

80%

Procyk B. , Rogowska-Kwas R. , Reben M. , Lisiecki M. , Macuda J. , Dorosz D.

Optica Applicata

|

2005

|

tom Vol. 35, nr 4

775-781

EN

Tests on glass texture were made in order to establish the size of porous space in modified glasses Al2O3 from the system Na2O-B2O3-SiO2 after extraction of dissolved boron phase during chemical treatment. A difference was observed in the size and volume of mezo- and micropores in 0.6% and 0.3% Al2O3 glasses depending on temperature of heating. Accounting for the difference of glass structure attempts were made to use them for the selective sorption of hydrocarbons dissolved in water. It follows from the obtained results that differences in hydrocarbon removal are as much as tens of percent. The efficiency of removal is conditioned by the type of glass and grain size of glass applied for sorption.

9

Porous glasses as a substrate for sensor elements

70%

Evstrapov A. , Esikova N. , Rudnitskaya G. , Antropova T. V.

Optica Applicata

|

2010

|

tom Vol. 40, nr 2

333--340

EN

The properties of porous glasses are determined by optical spectroscopy and high-resolution microscopy at different stages of immunoglobulin immobilization and after immune reaction. The influence of duration and temperature of drying between surface activation and silanization is studied. The quantity of protein immobilized on the porous glass surface is estimated by the Coomassie method. Various ways of surface silanization with the use of toluene and acetone are compared. The possibility of fabricating a microsensor element based on the porous glass for microchip is presented.

10

PALS investigations of matrix Vycor glass doped with molecules of luminescent dye and silver nanoparticles. Discrepancies from the ETE model

70%

Gorgol M. , Jasińska B. , Reisfeld R.

Nukleonika

|

2015

|

tom Vol. 60, No. 4, part 1

717--720

EN

A thermal stability of three materials: undoped reference Vycor glass, glass filled with ROT-305 red dye, and silver nanoparticles was investigated by positron annihilation lifetime spectroscopy (PALS) in a broad temperature range (from 93 to 473 K). The attempt of pore size calculations from the ortho-positronium lifetime data was performed using the extended Tao-Eldrup (ETE) model. Below room temperature, a significant decrease in lifetime values of the longest-lived component was found for all the samples. This effect could not be explained by thermal shrinkage of the material and is probably caused by interaction of -Ps with a Vycor glass matrix. The greatest discrepancy from the ETE model predictions was observed for the reference glass. Doping the base material with dye molecules and silver nanoparticles resulted in similar small decrease in this discrepancy. After reheating the samples to the room temperature, the PALS components returned to the initial values. In the temperature range of 293–473 K, quite good agreement between PALS results and the ETE model predictions was observed for the reference glass and the glass incorporated with dye molecules. The observed small discrepancy in this range could possibly be partly explained by thermal expansion of the material. For the glass doped with silver nanoparticles, a significant change in PALS parameters was observed in the temperature range from 403 to 473 K.

11

Nature of gas sensitivity of dyes on the base of Sn(IV) complexes

70%

Doycho I. K. , Gevelyuk S. A. , Lepikh J. I. , Rysiakiewicz-Pasek E.

Optica Applicata

|

2019

|

tom Vol. 49, nr 3

427--436

EN

Sensitivity of dyes on the base of 4-valence tin complexes to the composition of environment was researched. It has been found out that such dyes by themselves keep stability and inactivity to the composition of atmosphere. However, the photoluminescence properties of the nanostructures on their base can differ sufficiently depending on conditions of their formation. So the glow intensity of the nanoparticle ensembles of dyes having amine substitute in the hydrazonic fragment depends on the concentration of solution which was used during their formation. Optimal concentration exists and its excess leads to weak luminescence due to concentration quenching. Thus, if the nanoparticle ensemble, which was formed at the optimal concentration will be placed into ammonium atmosphere, it will be equivalent to formation of this ensemble by inflated concentration of the saturated solution. So photoluminescence of such system will be weak. Thereby reduced glow intensity will keep sufficiently long time due to the appearance of leakage channels in the form of bridge bonds. In such manner one can register the presence of ammonium in the environment. Initial intensity of luminescence may be re-established by removing extraneous gas with the aid of the short-time low-temperature anneal. In addition, the ligand in the coordination set of the dye plays a part of an interstitial impurity, so its presence leads to certain distribution of the charges in the system. It has been estimated experimentally that less intensive glow corresponds to the charge distribution in the system with the one-dentant ligand, namely by higher content of chlorine ions than in the case of bi-dentant one. This difference is more evident for dyes having hydroxyl substitute in the hydrazonic fragment. Thus, if the nanoparticle ensemble of such dye having a bi-dentant ligand will be placed into the atmosphere containing hydrogen chloride vapours, it changes the charge distribution to the typical one for the dye having one-dentant ligand artificially. It also will lead to weakening of the glow of the system. Initial intensity of luminescence may be re-established by removing the extraneous gas again with the aid of the anneal by the same conditions. The usage of specified properties makes it possible to construct reliable and responsive detectors of ammonium or hydrogen chloride vapours by the change of the detecting element in the known luminescence gas sensors to the nanoparticle ensemble of an appropriate dye.

12

Morphology of porous glasses. Colloid-chemical aspect

60%

Antropova T.

Optica Applicata

|

2008

|

tom Vol. 38, nr 1

5-16

EN

A summarizing of the results of complex study of pore morphology of porous glasses has been carried out taking into consideration the dissolved secondary silica state in the systems alkali borosilicate glass - a leaching solution. An influence of the composition and phase structure of an initial glass, and their leaching conditions, on the colloid-chemical characteristics of the porous glasses has been shown. The polymodal micro porous substructure and meso porous one, the size and a form of the pores and secondary silica particles as well as the fractal dimensions of their aggregates, the coefficients of structural resistance and tortuosity of the pores has been discussed.

13

Effect of antibiotic insertion on photoluminescent properties of silicate porous glasses used in ophthalmologic prostheses

60%

Rysiakiewicz-Pasek E. , Gevelyuk S. A. , Doycho I. K. , Prokopovich L. P. , Safronsky E. D.

Optica Applicata

|

2003

|

tom Vol. 33, nr 1

33-39

EN

The selection of silica porous glass being the most suitable material for manufacturing of the actuated scleral part of the eye prosthesis has been justified. The model explaining the photoluminescence intensity oscillations of porous glass during the effusion of the antibiotic out of the glass has been proposed. Multiple usage of the antibiotic has been found to lead to the etching effect of the porous glass and a method of minimization of the effect has been presented.

14

Physical adsorption in porous glasses

60%

Ovechko V. , Dmytruk A. , Mygashko V.

Optica Applicata

|

2003

|

tom Vol. 33, nr 1

41-44

EN

We have presented the results of our investigation concerning adsorption in porous glass (PG). Chemical adsorption of gas molecules is due to indicator substances which were deposited from solution on the surface of pores. Physical adsorption of organic molecules is due to OH-adsorption centres which are always arranged on the surface of PG at room temperature. Adsorption processes were investigated with infrared spectroscopy.

15

Evaluation of thin Ta(N) film integrity deposited on porous glasses

60%

Shamiryan D. , Baklanov M. R. , Yanovitskaya A. V. , Zverev A. V. , Tőkei Z. , Iacopi F. , Maex K.

Optica Applicata

|

2003

|

tom Vol. 33, nr 1

91-96

EN

Porous glasses are widely used in microelectronics as inter-metal dielectrics with low dielectric constant (so-called low-k dielectrics). At the same time copper is used as a metal because of its low resistivity. Combination of Cu and low-k requires a barrier to prevent Cu diffusion into a low-k dielectric. Integrity of such a barrier becomes an issue when porous glass is used as a low-k dielectric. The barrier should be as thin as possible and fully dense at the same time. Using solvent (toluene) penetration through a barrier (tantalum nitride in our case, which is non-stoichiometric, hence denoted as Ta(N)) and adsorption in porous glass as a barrier integrity probe, we show that barrier integrity depends not only on porous structure of the glass, but also on its chemical composition (namely on carbon content). Glasses with high carbon content are easier to seal with Ta(N) barrier. With help of Monte Carlo simulations, we speculate that different chemical composition of the porous glass results in different surface diffusion during barrier deposition. Different surface diffusion, in turn, results in different integrity of the porous barrier.

16

Small doses γ-irradiation effect on the photoluminescence properties of porous glasses

60%

Doycho I. K. , Gevelyuk S. A. , Kovalenko M. P. , Prokopovich L. P. , Rysiakiewicz-Pasek E.

Optica Applicata

|

2003

|

tom Vol. 33, nr 1

55-65

EN

The g-irradiation effect on the photoluminescence of various types of porous silica glasses and on its change during a half-year storage has been studied. It has been revealed that the photoluminescence intensity of glasses with fine matrix and almost complete absence of silica gel does not change when irradiated at applied doses, but a long-wave shift of its maximum position is observed. The increase in photoluminescence intensity appeared to be the most stable in glasses with the thick-wall matrix. The model which explains apparent changes in photo-luminescent properties and also allows us to draw conclusions about some features of various types of porous silicate glasses structure has been presented.

17

Effect of restricted geometry on structural phase transitions in KH2PO4 and NH4H2PO4 crystals

60%

Tarnavich V. , Korotkov L. , Karaeva O. , Naberezhnov A. , Rysiakiewicz-Pasek E.

Optica Applicata

|

2010

|

tom Vol. 40, nr 2

305--309

EN

The dielectric response of crystalline NH4H2PO4 and KH2PO4–SiO2 and NH4H2PO4–SiO2 composites prepared by embedding salts into porous glasses with the average pore diameter of 320 nm has been studied at the temperature range of 85–300 K. An increase of the structure phase transition temperatures in embedded salts has been observed, which is supposedly due to tensile deformations of embedded crystalline particles. The antiferroelectric phase transition in confined ADP particles becomes diffuse in the temperature region around 10 K.

18

Spectral characteristics and structure of porous glasses

60%

Evstrapov A. , Esikova N. , Antropova T. V.

Optica Applicata

|

2005

|

tom Vol. 35, nr 4

753-759

EN

The paper presents a method for the size estimation of scattering structures in porous glasses, being based on measurements of both the sample reflection and transmission. Analysis of the transmission spectra allows us to estimate the contribution of absorption and scattering to light extinction and to choose a wave range where the characteristics of a medium can be determined by means of simple and effective models. Optical characteristics of the highly light scattering samples can be obtained with use of the Gurevich-Kubelka-Munk method.

19

Changes in cell numbers and the ATP content in immobilized yeast cells during the continuous ethanol fermentation

60%

Paterczyk J. , Trzcinska M. , Sieliwanowicz B.

|

nr 4

20

Pore size determination by positron annihilation lifetime spectroscopy

51%

Jasińska B. , Dawidowicz A. L. , Goworek T. , Wawryszczuk J.

Optica Applicata

|

2003

|

tom Vol. 33, nr 1

7-12

EN

Two Vycor glasses were investigated using PALS method. The model of pick-off annihilation in cylindrical free volume was applied to evaluate the pore radii. The o-Ps mean lifetime value in the pores changed from 6.5 to 40 ns in one glass, while from 13 to 51 ns in the other (softer) one. The determined pore radii, using a cylindrical shape model, were from 0.5 to 1.4 nm and from 0.7 to 1.6 nm, respectively.