Wyniki wyszukiwania - BazTech

1

Analysis of influence of the shape of cutting insert on change of the parameter value describing the deviation of the profile of surface roughness

Pelc A.

Journal of KONES

|

2018

|

Vol. 25, No. 1

317--323

EN

The article presents the influence of the shape of the cutting insert on the surface roughness of the material after medium-fine turning machining. The analysis of measurements of the Ra parameter describing the arithmetic mean deviation of the surface roughness profile from the centre line of the profile by the mechanical and contact method was made using the Hommel Etamic Waveline 20 profile (Gdynia Maritime University). The tests were carried out on three stainless steel X2CrNiMo17-12-2 / 1.4404 shafts with a diameter of 80 mm, subjected to medium-precision turning machining at a length of 270 mm, using three cutting inserts made of tungsten carbide shaped T – triangular, C – rhombic, W – trigonal manufactured by Pafana. Values of used parameters are turning speed Vc = 150 m/min, depth of cut ap = 2 mm and feed f = 0.2 mm/rev. The parameters have been selected according to the manufacturer’s recommendations. The tests were carried out three times, five measurements on the length of the turned part of the rollers. The first test was made after collecting one layer of material, the second test was carried out after collecting five layers of material, and the third test was made after collecting nine layers of material. The article describes the differences between the used tiles and their effect on surface roughness, presents the results of the research, charts of measurements with averaged values and descriptive statistics of the Ra parameter were presented. It was noted that for all measurements of the Ra parameter, the smallest values were obtained using a W-shaped cutting insert. The Ra parameter using the C and T shaped plates increases with each subsequent measurement. The largest value of the Ra parameter is obtained using the T.

2

Deterministic Meeting of Sniffing Agents in the Plane

Elouasbi S., Pelc A.

Fundamenta Informaticae

|

2018

|

Vol. 160, nr 3

281--301

EN

Two mobile agents, starting at arbitrary, possibly different times from arbitrary locations in the plane, have to meet. Agents are modeled as discs of diameter 1, and meeting occurs when these discs touch. Agents have different labels which are positive integers. Each agent knows its own label, but not the label of the other agent. Agents are equipped with compasses and have synchronized clocks. They make a series of moves. Each move specifies the direction and the duration of moving. This includes a null move which consists in staying inert for some time, or forever. In a non-null move agents travel at the same constant speed, normalized to 1. We assume that agents have sensors enabling them to estimate the distance from the other agent (defined as the distance between centers of discs), but not the direction towards it. We consider two models of estimation. In both models an agent reads its sensor at the moment of its appearance in the plane and then at the end of each move. This reading (together with the previous ones) determines the decision concerning the next move. In both models the reading of the sensor tells the agent if the other agent is already present. Moreover, in the monotone model, each agent can find out, for any two readings in moments t1 and t2, whether the distance from the other agent at time t1 was smaller, equal or larger than at time t2. In the weaker binary model, each agent can find out, at any reading, whether it is at distance less than ρ or at distance at least ρ from the other agent, for some real ρ > 1 unknown to them. Such distance estimation mechanism can be implemented, e.g., using chemical sensors. Each agent emits some chemical substance (scent), and the sensor of the other agent detects it, i.e., sniffs. The intensity of the scent decreases with the distance. In the monotone model it is assumed that the sensor is ideally accurate and can measure any change of intensity. In the binary model it is only assumed that the sensor can detect the scent below some distance (without being able to measure intensity) above which the scent is too weak to be detected. We show the impact of the two ways of sensing on the cost of meeting, defined as the total distance travelled by both agents until the meeting. For the monotone model we show an algorithm achieving meeting at cost O(D), where D is the initial distance between the agents. This complexity is optimal. For the binary model we show that, if agents start at distance smaller than ρ (i.e., when they sense each other initially) then meeting can be guaranteed at cost O(ρ log λ), where λ is the larger label, and that this cost cannot be improved in general. Finally we observe that, if agents start at distance αρ, for some constant α > 1 in the binary model, then sniffing does not help, i.e., the worst-case optimal meeting cost is of the same order of magnitude as without any sniffing ability.

3

Sposoby oddymiania wielostanowiskowych garaży zamkniętych - studium przypadku

Skrzyniowska D., Pelc A., Skrzyniowski A.

Ciepłownictwo, Ogrzewnictwo, Wentylacja

|

2018

|

T. 49, nr 10

412--419

PL

W artykule przedstawiono systemy oddymiania garaży zamkniętych wraz z analizą techniczno-ekonomiczną na przykładzie garażu podziemnego. Opisano dwa rozwiązania wentylacji garaży zamkniętych (wentylacja kanałowa i wentylacja strumieniowa) stosowane jako systemy oddymiania garaży i parkingów podziemnych. W analizie techniczno-ekonomicznej oraz do weryfikacji przyjętych założeń i poprawności działania systemów zastosowano symulację komputerową CFD.

EN

This publication presents solutions used for ventilation in multi-space covered car parks together with techno-economic comparison of such systems based on the example of underground car park with fire and smoke simulation-assisted verification in CFD. In this article s theoretical two solutions of covered car park ventilation (duct and jet ventilation) used as smoke and heat control systems along with polish and foreign regulations for covered car parks are outlined. Additionally the article consists of an analysis of conditionings which affect functioning of such systems and comparison of such systems in technical and economic terms with the use of traditional duct and ductless systems – also called jet ventilation in underground car park. The proving of alternative designs is frequently undertaken by Computational Fluid Dynamics (CFD) analysis.

4

The effect of measurement method for assessing stereometric structure of surface

Pelc A., Starosta R.

Journal of KONES

|

2017

|

Vol. 24, No. 2

177--182

EN

The article presents the influence of measuring methods of surfaces topography evaluation. Surface topography was measured using a mechanical, contact method by Hommel Tester T-8000-R60 profilometer (Gdynia Maritime University) and using the contactless, optical method by Olympus Lext OLS4100 Confocal Laser Scanning Microscope (Gdynia Maritime University). A pattern of roughness grade 4 sample was studied (standards PN-58/M-02425 (Ra=10 μm, Rz=40 μm)). Seven measurements were made on each of devices, resulting in a more accurate stereometric image of the sample surface. The area of the test was 1.5×1.5 mm. The radius of the edge of the blade imaging the surface used in the contact method was 2 μm. In the case of the optical method, the test sample surface was subjected to a laser light 405 nm long. This article describes the principle of used measuring instrument operation and their advantages and disadvantages. The results and descriptive statistics (Mann–Whitney U test, Kolmogorov–Smirnov test) of surface altitude parameters, such as Sa, Sp, Sq, Sv, Sz. There were statistically significant differences in topography values between measurements by T-8000 profilometer and Confocal Laser Scanning Microscope. It was noted that the values of the parameters Sa, Sq are higher with the T-8000 profilometer as a measuring device. The parameters Sp, Sv, Sz have a higher value, when measured on a Confocal Laser Scanning Microscope.

5

Badania izotopowe δ18O, δD oraz δ37Cl w wybranych wodach mineralnych Podkarpacia

Baran I., Baran A., Pelc A., Hałas S., Chmiel S.

Przegląd Geologiczny

|

2015

|

Vol. 63, nr 3

172–-178

EN

The paper presents new results of stable isotope ratios (18O16O, 2H/1H and 37Cl/35Cl) in a few representative mineral waters of the Subcarpathian area. The observed temporal variability of 18O/16O and 2H/1H in waters has thrown a new light onto the origin of these waters. Analysis of 37Cl/35Cl in chlorine ion is indicative of its origin, at least it was possible to exclude a contamination by chloro-organic compounds. The possibility of tracing of migration of this pollution type by simultaneous analysis of chlorine and carbon isotopes is discussed. The results are discussed on the background of geological structures of the aquifers and their hydrogeological conditions.

6

Communication Complexity of Consensus in Anonymous Message Passing Systems

Fusco E. G., Pelc A.

Fundamenta Informaticae

|

2015

|

Vol. 137, nr 3

305--322

EN

We consider the message complexity of achieving consensus in synchronous anonymous message passing systems. Unlabeled processors (nodes) communicate through links of a network. An adversary wakes up some subset of processors at possibly different times and assigns them arbitrary numerical input values. All other processors are dormant and do not have input values. Any message wakes up a dormant processor. The goal of consensus is to have all processors agree on one of the input values. We seek deterministic consensus algorithms using as few messages as possible. As opposed to most of the literature on consensus, the difficulty of our scenario are not faults (we assume that the network is fault-free) but the arbitrary network topology combined with the anonymity of nodes. For n-node networks of unknown topology we show a consensus algorithm using Ώ(n2) messages; this complexity is optimal for this class. We show that if the network topology is known, then the complexity of consensus decreases significantly. Our main contribution is an algorithm that uses Ώ(n2/3 log2 n) messages on any n-node network and we show that some networks require (n log n) messages to achieve consensus.

7

Pochodzenie mineralnych wód chlorkowo-sodowych w rejonie Rzeszowa w świetle badań izotopowych(δ18O i δD, δ13C, δ37CL) i chemicznych

Baran A., Pelc A., Chmiel S., Hałas S.

Przegląd Geologiczny

|

2012

|

Vol. 60, nr 12

657–-664

EN

Several decades ago during exploration for additional resources of tap water a saline water deposit (Cl-Na, J, Fe, B type) has been discovered in the area of Rzeszów hospital park. Nowadays this water is exploited for balneological purposes. In the frame-work of this study for the first time the following stable isotopes: (δ18 i δD, δ13C, δ37Cl) and radiocarbon were determined in order to elucidate the origin of water, its mineralization and quality. Oxygen and hydrogen isotope data leads to conclusion that these waters were formed in a warm pre-Pleistocene period or they are mixture of Miocene seawater with Pleistocene infiltration waters. Carbon isotopic composition (b13= –8.65‰) of bicarbonate is characteristic for deep pore waters occurring in sedimentary rocks, whereas distinctly positive and negative δ37 Cl value rather excludes origin of chlorine ion from an open sea basin. Absence of radiocarbon (in Rzeszów well) indicates no admixture of recent infiltration waters, hence these waters are well preserved from anthropogenic pollution. This is further confirmed by very low concentration of nitrate.

8

Geochemical methods of inference the thermoregulatory strategies in Middle Triassic marine reptiles - a pilot study

Surmik D., Pelc A.

Contemporary Trends in Geoscience

|

2012

|

Vol. 1, iss. 1

87--91

EN

The oxygen stable isotopes investigation to elucidate thermoregulatory strategies in Middle Triassic basal sauropterygians is currently ongoing at University of Silesia and University of Maria Curie-Skłodowska. The results of similar studies on Late Mesozoic marine reptiles indicate that some of fully aquatic reptiles like plesiosaurs or ichthyosaurs could be warm-blooded animals. Our investigation is an important part of the aim of the research project "The Marine and Terrestrial reptiles in the Middle Triassic environmental background of Southern Poland" to solve the thermoregulation issue in basal marine reptiles and show how, and when did homoiothermy evolve in Sauropterygia. Homeothermy and gigantothermy were important physiological adaptations which allowed sauropterygian ancestors to leave the shores and conquer the open seas and oceans.

PL

Badania nad paleofizjologią kopalnych kręgowców ostatnimi laty stały się niezwykle modne. Polegają one na kompilacji danych uzyskanych wieloma komplementarnymi metodami z zakresu fizjologii (badania współczesnych form, zgodnie z zasadą aktualizmu) i geochemii izotopowej. Szczególnie interesujące stały się kwestie gospodarki termicznej u gadów kopalnych, które silnie dyskutowane są w kręgach badaczy dinozaurów (Reid, 1997; Ruben i in., 1996). Badania na izotopach stabilnych tlenu szkliwa zębowego przeprowadzone na obligatoryjnie morskich gadach okresu jurajskiego i kredowego (Bernard i in., 2010; zob. także Motani, 2010) wskazują, że ichtiozaury i plezjozaury późniejszego mezozoiku mogły być zwierzętami stałocieplnymi. Brak obecnie jednoznacznych danych dotyczących gospodarki termicznej bazalnych przedstawicieli gadów morskich z triasu, choć przyjmuje się, że te zamieszkujące nadbrzeżne i marginalne strefy mórz zwierzęta były gadami zmiennocieplnymi (pojkilotermicznymi), podobnie jak współczesny legwan morski, czy też smok z Komodo. Czy przejście z pojkilo- do homojotermii było jedną z adaptacji umożliwiających mezozoicznym gadom morskim ekspansję na otwarte morza? Na pytanie w jaki sposób ewoluowała homojotermia u gadów morskich spróbuje odpowiedzieć projekt badawczy pt. "Gady morskie i lądowe na tle środowiska triasu środkowego południowej Polski", realizowany na Uniwersytecie Śląskim.

9

Oxygen isotope analysis of shark teeth phosphates from Bartonian (Eocene) deposits in Mangyshlak peninsula, Kazakhstan

Pelc A., Hałas S., Niedźwiedzki R.

Mineralogia

|

2011

|

Vol. 42, iss. 1

53--61

EN

We report the results of high-precision (±0.05‰) oxygen isotope analysis of phosphates in 6 teeth of fossil sharks from the Mangyshlak peninsula. This precision was achieved by the offline preparation of CO2 which was then analyzed on a dual-inlet and triple-collector IRMS. The teeth samples were separated from Middle- and Late Bartonian sediments cropping out in two locations, Usak and Kuilus. Seawater temperatures calculated from the δ18O data vary from 23–41oC. However, these temperatures are probably overestimated due to freshwater inflow. The data point at higher temperature in the Late Bartonian than in the Middle Bartonian and suggest differences in the depth habitats of the shark species studied.

10

Wytwarzanie jonów ujemnych z SF₆ za pomocą termoemisyjnego źródła jonów

Pelc A.

Elektronika : konstrukcje, technologie, zastosowania

|

2011

|

Vol. 52, nr 8

77-79

PL

W pracy przedstawione są wyniki badań wytwarzania jonów ujemnych z SF₆. Jony ujemne otrzymywane były przy użyciu nowo skonstruowanego termoemisyjnego, gazowego źródła jonów i analizowane w spektrometrze mas z pojedynczym sektorem magnetycznym. Zaobserwowano aniony SF₅⁻, F⁻, SF₆⁻, SF₄⁻ oraz SF₃⁻ o stosunkach prądów jonowych wynoszących odpowiednio 1000:150:80:10:5:0,5. Ze względów energetycznych jon macierzysty SF₆ może powstać podczas bezpośredniego przyłączenia swobodnego elektronu do molekuły SF₆. Pozostałe jony mogą być wytwarzane zarówno w procesie fragmentacji SF₆⁻ jak też poprzez dysocjację termiczną i następujący po niej wychwyt elektronu przez powstałe fragmenty. Pomiary tła dla jonu F⁻ (po odcięciu dozowania sześciofluorku siarki) sugerują powstawanie HF na ściankach źródła jonów.

EN

Results of studies of the negative ions formation from SF6 are presented in this work. Using the mass spectrometer with magnetic sector field, ions obtained in the thermoemission, gaseous ions source were analyzed. Five ion species: SF₅⁻, F⁻, SF₆⁻, SF₄⁻ and SF₃⁻ with ions currents intensities ratios 1000:150:80:10:5:0,5, respectively, were measured. From the energetic point of view the SF₆⁻ anion can be formed by the direct free electron attachment to the SF₆ molecule. The other ions may be generated both in the fragmentation process of SF₆ and by the thermal dissociation followed by the electron capture to the fragments formed. Background signal from F⁻ (after the gas admission was stopped) suggest HF formation on the wali of ion source.

11

Trochoidalny monochromator energii elektronów

Pelc A.

Elektronika : konstrukcje, technologie, zastosowania

|

2009

|

Vol. 50, nr 1

112-114

PL

Trochoidalny monochromator energii elektronów (TEM) jest szczególnie efektywnym monochromatorem w przypadku wytwarzania wiązek elektronów o niskiej energii. W pracy tej została opisana zasada działania TEM. Przy użyciu skonstruowanego TEM otrzymano wiązkę elektronów o energiach z przedziału od około 0 do 10 eV. Najmniejszy rozrzut energetyczny otrzymanej wiązki elektronowej wynosił 52 meV przy natężeniu prądu elektronowego 3 nA. Przy większym rozrzucie energetycznym - 150 meV, natężenie prądu elektronowego wynosiło 70 nA.

EN

Electron monochromator being operated with an axial (parallel to electron beam) magnetic field is very suitable for the very low energy electron beams. This type of monochromator is called Trochoidal Electron Monochromator (TEM). The principle of operation and tests of the TEM are described in this contribution. Using newly constructed TEM the electron beam with energy range from about 0 to 10 eV was achieved. We achieved maximum electron energy resolution (at FWHM) of 52 meV, with rather small electron current intensity of 3 nA. At lower resolution of 150 meV the electron current intensity was 70 nA, respectively.

12

Spektrometr mas do analizy izotopowej chloru

Pelc A., Hałas S.

Elektronika : konstrukcje, technologie, zastosowania

|

2009

|

Vol. 50, nr 1

21-22

PL

Stosowana obecnie, a jednocześnie najbardziej precyzyjna metoda analizy stosunku izotopowego chloru oparta jest na spektrometrii mas z jonizującą wiązką elektronową (RMS). W metodzie tej chlor z próbki przekonwertowany do postaci chlorometanu (CH₃Cl) jest jonizowany wiązką elektronową i analizowany w sektorze magnetycznym spektrometru mas. Widmo masowe otrzymane tą metodą jest raczej skomplikowane, a stosunek natężeń prądów jonowych najbardziej efektywnie generowanych jonów (masa-52/masa-50) różni się od stosunku izotopowego ³⁷Cl/³⁵Cl. Ponadto tylko ok. 80% wszystkich formowanych w źródle jonów jest użyteczne w analizie (masa 52 i 50). Aby uniknąć tych problemów skonstruowaliśmy spektrometr jonów ujemnych, w którym zostało zmodyfikowane źródło jonów (w porównaniu do IRMS). W nowym typie źródła jony ³⁵Cl⁻ i ³⁷Cl⁻ są generowane z wydajnością zależną od materiału i temperatury katody.

EN

The most precise method of chlorine isotope analysis described to date is based on the isotope ratio mass spectrometry (IRMS) of chlorine quantitatively converted to chloromethane. The IRMS mass spectrum of chloromethane is rather complicated and the ratio of the most abundant peaks (mass-52/mass-50) differs from the isotope ratio. Moreover the electron impact ion source yields only ca. 80% of all ionic species at the useful masses 50 and 52. To overcome these drawbacks, we have devised a negative ion mass spectrometer in which the ion source was modified in comparison to the IRMS. In the type of the ion source the ³⁵Cl⁻ and ³⁷Cl⁻ ions are produced with efficiency dependent on the filament material and its temperature.

13

Impact of Asynchrony on the Behavior of Rational Selfish Agents

Ilcinkas D., Pelc A.

Fundamenta Informaticae

|

2008

|

Vol. 82, nr 1-2

113-125

EN

The behavior of rational selfish agents has been classically studied in the framework of strategic games in which each player has a set of possible actions, players choose actions simultaneously and the payoff for each player is determined by the matrix of the game. However, in many applications, players choose actions asynchronously, and simultaneity of this process is not guaranteed: it is possible that a player learns the action of another player before making its choice. Delays of choices are controled by the adversary and each player can only secure the worst-case payoff over the adversary's decisions. In this paper we consider such asynchronous versions of arbitrary two-person strategic games and we study how the presence of the asynchronous adversary influences the behavior of the players, assumed to be selfish but rational. We concentrate on deterministic (pure) strategies, and in particular, on the existence and characteristics of pure Nash equilibria in such games. It turns out that the rational behavior of players changes significantly if the decision process is asynchronous. We show that pure Nash equilibria often exist in the asynchronous version of the game even if there were no such equilibria in the synchronous game. We also show that a mere threat of asynchrony in the game may make social optimum a rational choice while it was not rational in the synchronous game.

14

Complexity of Searching for a Black Hole

Czyzowicz J., Kowalski D., Markou E., Pelc A.

Fundamenta Informaticae

|

2006

|

Vol. 71, nr 2,3

229-242

EN

A black hole is a highly harmful stationary process residing in a node of a network and destroying all mobile agents visiting the node, without leaving any trace. We consider the task of locating a black hole in a (partially) synchronous network, assuming an upper bound on the time of any edge traversal by an agent. The minimum number of agents capable to identify a black hole is two. For a given graph and given starting node we are interested in the fastest possible black hole search by two agents, under the general scenario in which some subset of nodes is safe and the black hole can be located in one of the remaining nodes. We show that the problem of finding the fastest possible black hole search scheme by two agents is NP-hard, and we give a 9.3-approximation for it.

15

Mass spectrometric investigations of electron attachment to molecules

Pelc A., Sailer W., Scheier P., Märk T. D.

Prace Naukowe Politechniki Warszawskiej. Elektronika

|

2005

|

z. 153

75-78

EN

Low energy electron attachment to nitro compounds (nitromethane, nitroethane and nitrobenzene) in the gas phase is reported in the electron energy range from zero up to about 10 eV with an energy resolution of 120 meV. Dissociative and nondissociative (only in nitrobenzene case) electron attachment were observed. Based on the comparison of the of the abundance of studied ions with CI in the dissociative electron attachment to CCI(4) at 0,8 eV the estimations for the all observed ions were obtained.

16

Leader election in rings with nonunique labels

Dobrev S., Pelc A.

Fundamenta Informaticae

|

2004

|

Vol. 59, nr 4

333--347

EN

We consider the leader election problem in a ring whose nodes have possibly nonunique labels. Every node knows a priori its own label and two integers, m and M, which are, respectively, a lower and an upper bound on the (unknown) size n of the ring. The aim is to decide whether leader election is possible and to perform it, if so. We consider both the synchronous and the asynchronous version of the problem and we are interested in message complexity in both cases. For the synchronous version we present an algorithm using O(n logn) messages and working in time O(M). Moreover, our algorithm uses O(n) messages when all identifiers are distinct. For the asynchronous version we show an Ω(nM) lower bound on message complexity for this problem, and present an algorithm for it using O(nM) messages.

17

Deterministic Computations on a PRAM with Static Processor and Memory Faults

Chlebus E., Gąsieniec L., Pelc A.

Fundamenta Informaticae

|

2003

|

Vol. 55, nr 3,4

285-306

EN

We consider Parallel Random Access Machine ( pram) which has some processors and memory cells faulty. The faults considered are static, i.e., once the machine starts to operate, the operational/faulty status of pram components does not change. We develop a deterministic simulation of a fully operational pram on a similar faulty machine which has constant fractions of faults among processors and memory cells. The simulating pram has n processors and m memory cells, and simulates a pram with n processors and a constant fraction of m memory cells. The simulation is in two phases: it starts with preprocessing, which is followed by the simulation proper performed in a step-by-step fashion. Preprocessing is performed in time O((m/n+ logn)logn). The slowdown of a step-by-step part of the simulation is O(logm).

18

Numerical analysis of peristaltic blood flow in arteries

Paszyński M, Pelc A.

Computer Assisted Mechanics and Engineering Sciences

|

2001

|

Vol. 8, No. 4

513-526

EN

The problem of blood flow in arteries induced by peristaltic waves has been investigated. The methodology of modelling global circulation system has been outlined. Medical measurements required for problem formulation have been presented. Numerical solutions of blood flow in artery based on finite element method have been worked out. The paper presents local model of pulsatile blood flow in the human artery. Modelling of pulsatile flow in cardiovascular system could improve understanding and interpretation of flow measurements in arteries locally as well as ventricular-vascular interaction in healthy patients at rest and while exercising. Results achieved on local models could be generalized to formulate a global model of haemodynamics of cardiovascular system in man. This approach could help identifying physiology of optimal heart work at rest, physical activity and also in pathological conditions as hypertension, cardiac insufficiency, heart defects, coronary heart disease and origin and progression of artherosclerosis as well.

19

Reliable minimum finding comparator networks

Denejko P., Diks K., Pelc A., Piotrów M.

Fundamenta Informaticae

|

2000

|

Vol. 42, nr 3,4

235-249

EN

We consider the problem of constructing reliable comparator networks built from unreliable comparators. In case of a faulty comparator inputs are directly output without comparison. A trivial lower bound of W(logn +k) on the depth of n-input k-fault tolerant sorting network is well known. We are interested in establishing exact lower bounds on the depth of such networks. To this end we consider fairly simple minimum-finding networks. Our main result is the first nontrivial lower bound on depths of networks computing minimum among n > 2 items in the presence of k > 0 faulty comparators. We prove that the depth of any such network is at least max(élogn u+ 2k, logn + klog[logn/( k+1)]). We also describe a network whose depth nearly matches the lower bound.

20

Mass spectrometric investigations of gaseous micro-clusters

Michalak L., Pelc A.

Elektronika : konstrukcje, technologie, zastosowania

|

2000

|

Vol. 41, nr 11

18-22

EN

The production of carbon disulphide and ammonia micro-clusters by adiabatic gas expansion of CS2/Ar mixture or NH3 gas, respectively, is studied by using an electron impact ion source and a double focussing sector mass spectrometer. In adiabatic gas expansion technique a gas expands from a high-pressure gas chamber through a small orifice into vacuum. The structure and the energetic properties of molecules, the gas stagnation pressure and its temperature, the diameter and the shape of the expansion nozzle determine the amount of condensation. In this paper results of measurements of the generation of (CS2)n+ ( <=11) and (NH3)n+ (n <=14) ions versus the stagnation pressure and stagnation temperature are described for a range of operating conditions. The appearance potentials for selected ions and work function for macroscopic samples of CS2 and NH3 are determined.

PL

Jednym ze sposobów wytwarzania klasterów jest adiabatyczne rozprężanie gazów. W metodzie tej gaz znajdujący się w zbiorniku pod wysokim ciśnieniem wypływa przez mały otwór (dyszę) do obszaru niskiego ciśnienia. Zderzenia cząsteczek gazu podczas takiego wypływu mogą prowadzić do kondensacji gazu i wytworzenia klasterów. Wydajność klasteryzacji określona jest przez strukturę i energetyczne własności molekuł, ciśnienie i temperaturę gazu, rozmiary i kształt zastosowanej dyszy. Dla próbek ciekłych maksymalne ciśnienie w zbiorniku ograniczone jest przez prężność ich par. W tym przypadku, w celu otrzymania wiązki o żądanych parametrach i zintensyfikowania procesów zachodzących podczas wypływu stosuje się mieszaninę par badanej cieczy z gazem nośnym (Ar, Ne, N2). Rozróżnia się dwa typy klasyfikacji klasterów: pod względem energii wiązania poszczególnych molekuł w klasterze oraz pod względem rozmiaru klastera. Kiastery typu van der Waalsa (energia wiązania Ew = 0,01- 0,05 eV) zbudowane z n = 2 -13 molekuł zalicza się do tzw. mikroklasterów. W masowo-spektrometrycznych badaniach klasterów opisanych w tej pracy wiązka molekularna zawierająca kiastery wprowadzana jest poprzez przesłonę do źródła jonów, gdzie bombardowana jest wiązką elektronów o określonej energii i natężeniu. Powstałe jony analizowane są kolejno w sektorowych polach elektrycznym oraz magnetycznym podwójnie ogniskującego spektrometru mas. W pracy przedstawiono temperaturowe i ciśnieniowe charakterystyki formowania klasterów (CS2)n+ (n <=11) i ich homologów oraz klasterów (NH3)n+ (n <=14). Zaproponowano tu również możliwe procesy jonizacyjne dla jonów (CS2)n+, które powinny być brane pod uwagę przy interpretacji spektrum masowego zjonizowanych klasterów. Wyznaczono także potencjały pojawiania dla kilku jonów klasterów oraz oszacowano pracę wyjścia elektronu dla makroskopowych próbek CS2 i NH3.