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Number of results: 14
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Abstract

W roku 1887 Henryk Siemiradzki namalował obraz zatytułowany Chopin w salonie księcia Antoniego Radziwiłła w roku 1829. Obraz przedstawia scenę, w której gry Chopina słuchają członkowie rodziny książęcej oraz zaproszeni goście, wśród których znajduje się znany badacz przyrody Alexander von Humboldt. Siemiradzki opracował kompozycję obrazu na podstawie tekstu poznańskiego nauczyciela Marcelego Antoniego Szulca z roku 1873. Jednakże tekst Szulca jest autoryzowanym tłumaczeniem opowiadania napisanego przez niemiecką pisarkę Elise Polko w roku 1868. Obraz Siemiradzkiego był pokazywany w niektórych krajach europejskich w latach 1887–1892. W następnych latach znane były tylko kopie jego fotograwiury. Przez 106 lat obraz był uważany za zaginiony, aż pojawił się ponownie w roku 1998 w Nowym Jorku. Przeprowadzono analizę biograficzną okresów, w których Chopin, Humboldt i Radziwiłł mogli się spotkać jednocześnie. Jako miejsca spotkania tych osób rozpatrzono rezydencje księcia Radziwiłła w Berlinie, Poznaniu i Antoninie oraz Warszawę.
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Authors and Affiliations

Andrzej B. Więckowski
1

  1. Instytut Fizyki, Wydział Fizykii Astronomii, Uniwersytet Zielonogórski, Zielona Góra; Instytut Fizyki Molekularnej PAN,Poznań
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Abstract

The aim of the study was to analyse mechanical properties and microstructure of joints obtained using friction stir welding (FSW) technology. The focus of the study was on overlap linear FSW joints made of 1.4541 DIN 17441 steel sheets with thickness of 1.2 mm. Tools used during friction stir welding of steel joints were made of W-Re alloy. The joints were subjected to visual inspection and their load bearing capacity was evaluated by means of the tensile strength test with analysis of joint breaking mechanism. Furthermore, the joints were also tested during metallographic examinations. The analysis performed in the study revealed that all the samples of the FSW joints were broken outside the joint area in the base material of the upper sheet metal, which confirms its high tensile strength. Mean load capacity of the joints was 15.8 kN. Macroscopic and microscopic examinations of the joints did not reveal significant defects on the joint surface and in the cross-sections.

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Authors and Affiliations

W. Więckowski
P. Lacki
J. Adamus
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Abstract

The paper is intented to show a new, state space, discrete, non integer order model of a one-dimensional heat transfer process. The proposed model derives directly from time continuous, state space model and it uses the discrete Grünwald-Letnikov operator to express the fractional order difference with respect to time. Stability and spectrum decomposition for the proposed model are recalled, the accuracy and convergence are analyzed too. The convergence of the proposed model does not depend on parameters of heater and measuring sensors. The dimension of the model assuring stability and predefined rate of convergence and stability is estimated. Analytical results are confirmed by experiments.

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Authors and Affiliations

K. Oprzędkiewicz
K. Dziedzic
Ł. Więckowski
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Abstract

The iconic discovery in 1912 of X-ray diffraction by crystals has revolutionized physics, chemistry, biology, and ultimately also life sciences, by providing a powerful method for structural characterization of drugs and drug targets used in molecular medicine. The first X-ray diffraction was recorded by an assistant (Walter Friedrich) and PhD student (Paul Knipping) under the instruction of a theoretician Max (later von) Laue, who two years later was the sole recipient of a Nobel Prize (with the award ceremony in 1920) awarded for this discovery. The experimental setup, now on display in Deutsches Museum München, is labeled “the original Laue apparatus”, which is doubly incorrect: Laue himself never experimented with it, and it has a number of reconstructed parts due to loss, or even theft in the Museum itself. Also, the “first X-ray diffraction photograph” is enshrouded in a mist of ambiguity. Laue’s Nobel medal was deliberately dissolved in aqua regia to evade identification and confiscation by the Nazis. A replica was minted but it has been lost without a trace. The distorted (embellished) account of this fundamental discovery makes one wonder: is it acceptable to repeat narrations about scientific achievements with some departure from the historical truth? We answer “reluctantly yes”, with the caveat that all possible effort should be expended to rectify the picture. And this article is trying to achieve exactly this, with respect to one discovery in physics.
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Authors and Affiliations

Kamil F. Dziubek
1
Mariusz Jaskólski
2 3
ORCID: ORCID
Andrzej B. Więckowski
4 5

  1. Europejskie Laboratorium Spektroskopii Nieliniowej LENS, Sesto Fiorentino (Florencja), Włochy
  2. Instytut Chemii Bioorganicznej PAN
  3. Wydział Chemii, Uniwersytet im. Adama Mickiewicza w Poznaniu
  4. Wydział Fizyki i Astronomii, Uniwersytet Zielonogórski, Zielona Góra
  5. Instytut Fizyki Molekularnej PAN, Poznań

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