Jednostavna eksperimentalna provjera heisenbergovih relacija neodređenosti

We show that the quantum mechanical interpretation of the diffraction of light on a slit, when a wave function is assigned to a photon, can be used for a direct experimental study of Heisenberg\u27s position-momentum and equivalent position-wave vector uncertainty relation for the photon. Results of an experimental test of the position-wave vector uncertainty relation, where the wavelength is used as the input parameter, are given and they very well confirm our approach. The same experimental results can also be used for a test of the position-momentum uncertainty relation when the momentum p0 of a photon is known as the input parameter. We show that a measurement of p0, independent of the knowledge of the value of the Planck\u27s constant, is possible. Using that value of p0, a test of the position-momentum uncertainty relation could be regarded as a method for a direct measurement of the Planck\u27s constant. This is discussed, since the diffraction pattern is also well described by classical electrodynamics in the considered experimental conditions. This approach for testing the Heisenberg\u27s uncertainty relations is very simple and consequently suitable as a quantitative exercise in undergraduate experimental courses, as well as a visual and attractive demonstration of the Heisenberg\u27s uncertainty principle in courses of quantum mechanics.Pokazujemo da se kvantno-mehaničko tumačenje ogiba svjetlosti na pukotini, u kojem smo fotonu pridijelili uobičajenu valnu funkciju, može upotrijebiti za izravnu eksperimentalnu provjeru Heisenbergovih relacija neodređenosti položaj–impuls i ekvivalentnih položaj–valni vektor. Rezultati testiranja relacije neodređenosti položaj–valni vektor, u kojem smo uzeli valnu duljinu lasera kao ulazni parametar, dobro potvrđuju na pristup. Na istovjetan način se može napraviti provjera relacija neodređenosti položaj–impuls ako je impuls p0 laserskih fotona poznat kao ulazni parametar. Dokazujemo da je moguće mjeriti p0 neovisno o poznavanju vrijednosti Plankove konstante. S tako dobivenom vrijednošću p0 opisani eksperiment se može promatrati i kao način mjerenja Plankove konstante. To smo detaljnije pojasnili s obzirom da ogibnu sliku u danim eksperimentalnim uvjetima možemo također odlično opisati i klasičnom elektrodinamikom. Opisani eksperimentalni pristup za provjeru Heisenbergovih relacija neodređenosti je vrlo jednostavan, te je stoga pogodan kao vježba u studentskim praktikumima ali i kao vizualno atraktivna demonstracija na predavanjima iz kvantno-mehaničkih kolegija

A simple experimental checking of Heisenberg's uncertainty relations

We show that the quantum mechanical interpretation of the diffraction of light on a slit, when a wave function is assigned to a photon, can be used for a direct experimental study of Heisenberg's position-momentum and equivalent position-wave vector uncertainty relation for the photon. Results of an experimental test of the position-wave vector uncertainty relation, where the wavelength is used as the input parameter, are given and they very well confirm our approach. The same experimental results can also be used for a test of the position-momentum uncertainty relation when the momentum p_0 of a photon is known as the input parameter. We show that a measurement of p_0, independent of the knowledge of the value of the Planck's constant, is possible. Using that value of p_0, a test of the position-momentum uncertainty relation could be regarded as a method for a direct measurement of the Planck's constant. This is discussed, since the diffraction pattern is also well described by classical electrodynamics in the considered experimental conditions. This approach for testing the Heisenberg's uncertainty relations is very simple and consequently suitable as a quantitative exercise in undergraduate experimental courses, as well as a visual and attractive demonstration of the Heisenberg's uncertainty principle in courses of quantum mechanics

Jednostavna eksperimentalna provjera heisenbergovih relacija neodređenosti

We show that the quantum mechanical interpretation of the diffraction of light on a slit, when a wave function is assigned to a photon, can be used for a direct experimental study of Heisenberg\u27s position-momentum and equivalent position-wave vector uncertainty relation for the photon. Results of an experimental test of the position-wave vector uncertainty relation, where the wavelength is used as the input parameter, are given and they very well confirm our approach. The same experimental results can also be used for a test of the position-momentum uncertainty relation when the momentum p0 of a photon is known as the input parameter. We show that a measurement of p0, independent of the knowledge of the value of the Planck\u27s constant, is possible. Using that value of p0, a test of the position-momentum uncertainty relation could be regarded as a method for a direct measurement of the Planck\u27s constant. This is discussed, since the diffraction pattern is also well described by classical electrodynamics in the considered experimental conditions. This approach for testing the Heisenberg\u27s uncertainty relations is very simple and consequently suitable as a quantitative exercise in undergraduate experimental courses, as well as a visual and attractive demonstration of the Heisenberg\u27s uncertainty principle in courses of quantum mechanics.Pokazujemo da se kvantno-mehaničko tumačenje ogiba svjetlosti na pukotini, u kojem smo fotonu pridijelili uobičajenu valnu funkciju, može upotrijebiti za izravnu eksperimentalnu provjeru Heisenbergovih relacija neodređenosti položaj–impuls i ekvivalentnih položaj–valni vektor. Rezultati testiranja relacije neodređenosti položaj–valni vektor, u kojem smo uzeli valnu duljinu lasera kao ulazni parametar, dobro potvrđuju na pristup. Na istovjetan način se može napraviti provjera relacija neodređenosti položaj–impuls ako je impuls p0 laserskih fotona poznat kao ulazni parametar. Dokazujemo da je moguće mjeriti p0 neovisno o poznavanju vrijednosti Plankove konstante. S tako dobivenom vrijednošću p0 opisani eksperiment se može promatrati i kao način mjerenja Plankove konstante. To smo detaljnije pojasnili s obzirom da ogibnu sliku u danim eksperimentalnim uvjetima možemo također odlično opisati i klasičnom elektrodinamikom. Opisani eksperimentalni pristup za provjeru Heisenbergovih relacija neodređenosti je vrlo jednostavan, te je stoga pogodan kao vježba u studentskim praktikumima ali i kao vizualno atraktivna demonstracija na predavanjima iz kvantno-mehaničkih kolegija

Analysis of pulmonary surfactant by Fourier transform infrared spectroscopy after exposure to sevoflurane and isoflurane

Pulmonary surfactant, consisting primarily of phospholipids and four surfactant-specific proteins, is among the first structures that is exposed to inhalation anesthetics. Consequently, changes of pulmonary surfactant due to this exposure could cause respiratory complications after long anesthetic procedures. Fourier transform infrared (FTIR) spectroscopy was used to explore the effects of two inhalation anesthetics, sevoflurane and isoflurane, on a commercially available pulmonary surfactant. The research was primarily focused on the effect of anesthetics on the lipid component of the surfactant. Four different concentrations of anesthetics were added, and the doses were higher from the low clinical doses typically used. Recorded spectra were analyzed using principal component analysis, and the Student's t-test was performed to confirm the results. The exposure to both anesthetics induced similar changes, consistent with the increase of the anesthetic concentration. The most pronounced effect was on the hydrophilic head group of phospholipids, which is in agreement with the disruption of the hydrogen bond, caused by the anesthetics. A change in the band intensities of CH2 stretching vibrations, indicative of a disordering effect of anesthetics on the hydrophobic tails of phospholipids, was also observed. Changes induced by isoflurane appear to be more pronounced than those induced by sevoflurane. Furthermore, our results suggest that FTIR spectroscopy is a promising tool in studying anesthetic effects on pulmonary surfactant

A simple experimental checking of Heisenberg's uncertainty relations

We show that the quantum mechanical interpretation of the diffraction of light on a slit, when a wave function is assigned to a photon, can be used for a direct experimental study of Heisenberg's position-momentum and equivalent position-wave vector uncertainty relation for the photon. Results of an experimental test of the position-wave vector uncertainty relation, where the wavelength is used as the input parameter, are given and they very well confirm our approach. The same experimental results can also be used for a test of the position-momentum uncertainty relation when the momentum p_0 of a photon is known as the input parameter. We show that a measurement of p_0, independent of the knowledge of the value of the Planck's constant, is possible. Using that value of p_0, a test of the position-momentum uncertainty relation could be regarded as a method for a direct measurement of the Planck's constant. This is discussed, since the diffraction pattern is also well described by classical electrodynamics in the considered experimental conditions. This approach for testing the Heisenberg's uncertainty relations is very simple and consequently suitable as a quantitative exercise in undergraduate experimental courses, as well as a visual and attractive demonstration of the Heisenberg's uncertainty principle in courses of quantum mechanics

Procjena starosti i određivanje spola analizom ljudskog dentina s pomoću Ramanova spektra

Objectives: This study aimed to determine the sex and estimate the age of individuals by analysing Raman spectra obtained from extracted teeth dentine. Material and methods: A total of 25 male and 26 female extracted teeth were collected, disinfected, and fixed in auto acrylate before being cut near the cervical margin. The inclusion criteria were non endodontically treated teeth with the cervical third of the tooth crown preserved. The exposed dentine was recorded using a Raman spectrometer, with 100 scans per dentine site in the spectral range of 3500 to 200 cm -1 and a resolution of 4 cm -1 . Background-corrected, normalized, and decomposed spectra were subjected to principal component analysis using MATLAB 2010 (The MathWorks, Natick, MA, USA). To assess age differences, prominent vibrational bands were observed and statistically analyzed, while sex differentiation employed the T-test on acquired data, exploring vibrational bands with significant intensity differences. Results: The obtained results revealed a segmentation of spectra in the male sample group based on the age of teeth at extraction, with an accuracy of age estimation at 7.0048 years. A similar segmentation was observed in the female sample group, with an accuracy of 9.3863 years. Conclusion: The recorded spectra were organized into datasets and analyzed with principal component analysis, demonstrating the feasibility of sex determination and age estimation using Raman spectra of teeth. Differences in classification accuracy between sexes may be attributed to hormonally-mediated differences in the biochemical composition of dentine between males and females. The findings of this study can provide valuable insights into methods for forensic and anthropological applications.Ciljevi: Ramanovim spektrom željelo se odrediti spol i procijeniti starost pojedinaca analizom dentina iz izvađenih ljudskih zuba. Materijal i metode: Prikupljeno je ukupno 25 izvađenih zuba muškaraca i 26 od žena te su dezinficirani i fiksirani u autoakrilatu prije rezanja blizu cervikalnog ruba. Kriteriji za uključivanje bili su zubi koji nisu endodontski tretirani i s očuvanom cervikalnom trećinom krune. Izloženi dentin snimljen je Ramanovim spektrometrom – učinjeno je 100 skeniranja po mjestu dentina u spektralnom rasponu od 3500 do 200 cm -1 i razlučivošću od 4 cm -1 . Spektri s korekcijom pozadine podvrgnuti su analizi glavnih komponenti s pomoću MATLAB-a 2010 (The MathWorks, Natick, MA, SAD). Da bi se procijenile razlike u dobi, promatrane su i statistički analizirane vibracijske trake, a za diferencijaciju spola koristio se t-test na prikupljenim podatcima, istražujući vibracijske trake sa značajnim razlikama u intenzitetu. Rezultati: Rezultati su pokazali segmentaciju spektara u skupini s uzorcima zuba muškaraca na temelju dobi pri vađenju, s točnošću procjene starosti od 7,0048 godina. Slična segmentacija uočena je u skupini s uzorcima zuba žena, s točnošću od 9,3863 godina. Zaključak: Organizirani skupovi podataka snimljenih spektara podvrgnuti su analizi glavnih komponenti. Zabilježena je korelacija između očitanja Ramanova spektra i kronološke dobi ispitanika. Također je zabilježena korelacija između očitanja Ramanova spektra i biološkog spola. Razlike u točnosti klasifikacije između bioloških spolova pripisane su hormonski posredovanim razlikama u biokemijskom sastavu dentina između muškaraca i žena

Interaction of High Density Lipoprotein with Nicotine – an IR and Raman Study

The direct interaction of high density lipoprotein (HDL) with nicotine, one of the major components of cigarette particulate matter, has been studied here at molecular level. Nicotine affects the vibration modes of HDL due to its embedment within the lipid monolayer. The changes in the positions and intensities of vibration bands in protein and lipid domain of the particle were studied by IR and Raman spectroscopy. Three types of samples were prepared: native HDL sample and two HDL samples with added nicotine. The molecular ratio of nicotine /phospholipids in two samples was 1: 12 and 1: 6. The same types of samples were prepared from liposomes containing phosphatidylcholine, and sphingomyelin with addition of cholesterol. Spectra of liposome samples were used for distinguishing and attribution of lipid bands in spectra of HDL samples, where the majority of changes were observed. The incorporation of nicotine into lipid monolayer induces changes in the lipid bands from the vibrations in acyl chains and head groups of phospholipids. The changes in vibration bands from particular amino acids\u27 residues confirm that nicotine molecule is located within lipid monolayer but close to lipid-protein interface

Interaction of High Density Lipoprotein with Nicotine – an IR and Raman Study

The direct interaction of high density lipoprotein (HDL) with nicotine, one of the major components of cigarette particulate matter, has been studied here at molecular level. Nicotine affects the vibration modes of HDL due to its embedment within the lipid monolayer. The changes in the positions and intensities of vibration bands in protein and lipid domain of the particle were studied by IR and Raman spectroscopy. Three types of samples were prepared: native HDL sample and two HDL samples with added nicotine. The molecular ratio of nicotine /phospholipids in two samples was 1: 12 and 1: 6. The same types of samples were prepared from liposomes containing phosphatidylcholine, and sphingomyelin with addition of cholesterol. Spectra of liposome samples were used for distinguishing and attribution of lipid bands in spectra of HDL samples, where the majority of changes were observed. The incorporation of nicotine into lipid monolayer induces changes in the lipid bands from the vibrations in acyl chains and head groups of phospholipids. The changes in vibration bands from particular amino acids\u27 residues confirm that nicotine molecule is located within lipid monolayer but close to lipid-protein interface

Micro and Nano Structure of Electrochemically Etched Silicon Epitaxial Wafers

Silicon epitaxial wafers, consisting of 280 μm thick n-type substrate layer and 4–5 μm thick epitaxial layer, were electrochemically etched in hydrofluoric acid ethanol solution, to produce porous silicon samples. The resistivity of epitaxial layer was 1 Ω cm, while the substrate was much better conductor with resistivity 0.015 Ω cm. By varying the etching time, the micro- and nano-pores of different sizes were obtained within the epitaxial layer, and on the substrate surface. Due to the lateral etching the epitaxial layer was partially detached from the substrate and could be peeled off. The influence of etching time duration on the optical and structural properties of porous samples was investigated by Raman, infrared and photoluminescence spectroscopy. The samples were analysed immediately after the etching and six months later, while being stored in ambient air. The Raman spectra showed the shift in positions of transversal optical (TO) phonon bands, between freshly etched samples and the one stored in ambient air. Infrared spectra indicated the presence of SiHx species in the freshly etched samples, and appearance of oxidation after prolonged storage. Photoluminescence spectra were very weak in freshly etched samples, but their intensity has increased substantially in six month period. (doi: 10.5562/cca1971