The 21st International Conference on Global Research and Education, Inter-Academia 2024, continues the series organised by the Central European university community, primarily from Poland, Hungary, the Slovak Republic, and the Czech Republic, in collaboration with the Shizuoka University in Japan. Since 2002, the conference has been held annually in autumn, fostering enduring collaborations in critical domains of scientific and technological advancement alongside promoting excellence in higher education. 

Focusing on the most rapidly developing areas of mechatronics, this issue offers an in-depth discussion of the physics applied in modern materials engineering, particularly in the fields of inorganic semiconductors, carbon and polymeric materials, inorganic glasses, crystalline materials, and metamaterials. Furthermore, it encompasses subjects pertaining to system control, metrology and nanometrology, robotics, biomedical engineering, photonics, and micromachined micro-electromechanical systems. An  international  consortium  of   prominent  researchers from 11 countries has compiled the collection of articles. 

The proceedings are designed as an essential reference resource for academic, governmental, and industrial research and development sectors in the future. Moreover, we aspire for this volume to serve as the definitive reference for the global community in the field of mechatronics.

This issue includes 57 meticulously chosen contributions presented at the 21st International Conference Inter-Academia 2024,  hosted  by  Warsaw  University of Technology from September 4 to 6, 2024 in Warsaw and Pułtusk, Poland.

We express our appreciation to all authors for their contributions to this volume.

Ryszard Jabłoński

Roman Szewczyk

Anna Ostaszewska-Liżewska

Gerard Cybulski

Guest Editors 

The  paper of  the  month,  chosen  by  the Editor-in-Chief,  is  "Excitation of waves in a dispersive medium. Example of flow of a bubbly liquid"  by A. Perelomova;

DOI: 10.12693/APhysPolA.146.135

The paper by Perelomova concerns the excitation of waves in a dispersive medium, where the factor causing dispersion is the presence of bubbles. It is a theoretical study of the underlying one-dimensional equations that involve a moving exciter and the resulting dispersive waves. The Author clearly states what aspects of these equations have not been studied in enough detail and presents the solutions in these cases. An interesting discussion of mutual interaction of sound waves and entropy waves is given. It is shown, in particular, that the interaction can reduce the overall density by enlarging the bubbles. This is somewhat similar to isobaric acoustic heating.

I recommend this paper to all physicists interested in fluid mechanics and related phenomena.

The Editor-in-Chief

The proceedings volume contains selected papers presented during the 14th Symposium of Magnetic Measurements and Modelling "SMMM'2023", which took place in Zakopane (Poland), October 16–18, 2023. The Symposium was organized by the Częstochowa Branch of the Polish Society of Theoretical and Applied Electrical Engineering (PTETiS) in cooperation with the Faculty of Electrical Engineering of the Częstochowa University of Technology and the Institute of Metrology and Biomedical Engineering, Faculty of Mechatronics, Warsaw University of Technology.

The Symposium has emerged as a continuation of the Symposia of Magnetic Measurements held previously. The 14^th Symposium of Magnetic Measurements & Modelling provided an excellent opportunity for scientists and engineers dealing with magnetic measurements and modelling of magnetic properties to present and discuss the results of their research. The scope of the Symposium has been extended to include modelling of properties and applications of magnetic materials and covered the following topics: measurements of magnetic quantities, indirect measurements of physical quantities using magnetic measurements, measurement techniques in a high-frequency range, nondestructive evaluation of materials, modelling of magnetic properties, magnetocaloric and magnetomechanical effect, structure and properties of magnetic materials, sensors and actuators, magnetic circuits in electrical machines, mechatronics systems.

Over 30 people from domestic and foreign academic centres, research institutes and industry participated in the Symposium, including:

• Professor Marcos Flavio de Campos, UFF — Federal Fluminense University (Brasil);


• Professor Peter Kollár, Pavol Jozef Šafárik University in Košice (Slovakia);


• Professor Branko Koprivica, University of Kragujevac (Serbia);


• Łukasz Mierczak, PhD, Brockhaus Measurements (Germany);


• Professor Denisa Olekšáková, Technical University of Košice (Slovakia);


• Professor Zdenek Roubal, Brno University of Technology (Czech Republic).

During the Symposium, 7 sessions were organized and 28 presentations were presented. In the plenary session, two invited talks were given:

1. Ł. Mierczak, "Advanced measurement technologies for magnetic materials used in automotive applications",


2. M.F. de Campos, J.A. de Castro, "Comparative view of coercivity mechanisms in soft and hard magnetic materials".

The Organizing Committee would like to express its gratitude to all participants for the high-level presentation of their research, which concerned the scientific and engineering aspects of measurement and modelling the properties of soft magnetic materials. 

Jan Szczygłowski

Mariusz Najgebauer

Chair of the Conference

The  paper of  the  month,  chosen  by  the Editor-in-Chief,  is  "Optimum Heat Treatment Conditions Determination for Mg-Diffused MgB₂"  by Ö. Çiçek and K. Yakinci;

DOI: 10.12693/APhysPolA.145.324

Superconducting materials with high transition temperatures are intensively studied. One of them, magnesium diboride MgB₂ is one of them. It is a light weight superconducting material, it is relatively easy and cheap to obtain, therefore it has been extensively studied in recent years. Many applications of this material are possible due to its high transition temperature and other properties.  

The present paper discusses the production of MgB₂ by the Mg diffusion method. Extensive studies of the material microstructure were performed with the help of SEM and XRD. Also, the magnetic properties were determined and are presented in detail.

The results on the heat treatment for the production of MgB₂ in the presented method can be very helpful for many applications.

The editor recommends this paper to all readers interested in the technology of materials, superconductors in particular.

The Editor-in-Chief

The  paper of  the  month,  chosen  by  the Editor-in-Chief,  is  "Designing a Novel Trigonal Silicon Material: First-Principles Calculations"  by Q. Fan, Y. Li, R. Yang, X. Yu, and S. Yun;

DOI: 10.12693/APhysPolA.145.273

Silicon is one of the most studied materials due to its applications in the electronic industry. Silicon crystals can come in many allotropic types, two allotropes exist at room temperature: amorphous and crystalline with the diamond structure. Many other allotropes have been synthesized. Using first-principles density functional theory (DFT)  the  paper  predicts a new silicon allotrope called Tri-Si18. The atomic structure of Tri-Si18 belongs to the space group P3221 (trigonal crystal system), the unit cell contains 18 Si atoms and consists of five- and six-membered rings. A comprehensive study of structural, energetic, mechanical, electronic and thermal properties of this structure is presented in the paper and the system is shown to be stable. Mechanical, electrical and thermal properties of such crystals are found. The calculated electronic properties show that the system is an indirect band gap semiconductor with the energy gap of 1.77 eV.

All these properties of the novel silicon allotrope are very attractive. I am looking forward to the time when this form of silicon will be synthesized.

The Editor-in-Chief

The  paper of  the  month,  chosen  by  the Editor-in-Chief,  is  "Spin–Orbit Coupled Dynamics of Ferromagnetic Spinor Bose–Einstein Condensate"  by Qiang Zhao;

DOI: 10.12693/APhysPolA.145.162

Studies of Bose-Einstein condensates entered a new era. While the most fundamental properties of the condensates are known, researchers are iterested more in specific problems. Ferromagnetic condensates, containing polarized atoms with spin-1, are the subject of many recent studies. A characteristic feature of such condensates is that not only atoms with the same spin interact with each other, but the interaction between atoms with different spin components with possible spin exchange is crucial.

This paper delves into the dynamics of a spin-1 ferromagnetic spinor Bose-Einstein condensate. This should be contrasted with other studies that concentrate on static characteristics, like the shape of the ground state. Another novel feature of the present paper is a discussion of the role played by the trap shape. It is shown that the condensate dynamics considerably differs between the case of condensates in isotropic and anisotropic traps leading to different steady state structures. Thus, the paper gives a novel view on the dynamics of ferromagnetic condensates and is recommended not only for specialists in the field.

The Editor-in-Chief

The Zakopane School of Physics "Breaking Frontiers: Submicron Structures in Physics and Biology" was held in Zakopane, Poland, from 23 to 27 of May 2023. This conference is a recurrent event of an international range, organized since the mid-1960s and encompassing a wide scope of scientific problems related not only to novel measurement techniques, but also to the application of nuclear physics methods in the study of biomedical materials and condensed phase.

The School is directed to early career scientists: students, Ph.D. students, and adjuncts at the threshold of the scientific career, who can present the results of their work or consult experienced mentors in a pleasant atmosphere. Among the 80 participants, 19 leading specialists in material science, physics, and biology enriched the event with their insightful lectures. The subject matter of this year's meeting included: the applications of novel X-ray techniques, multifunctional materials, magnetic nanostructures, molecular magnets, and the applications of physics in biology and medicine. Two special sessions were organized as part of the event: the first one devoted to measurement possibilities with the use of the X-ray laser in Hamburg (European XFEL), and the second one to the ELI (Extreme Light Infrastructure) research infrastructure.

In addition to the formal scientific program, the School allocated time for informal meetings and discussions, fostering collaboration and the birth of new ideas and friendships. As in previous meetings, valuable conversations and exchanges of opinions took place during scientific sessions, excursions, and shared meals and coffee breaks.

The success of the School was a collective effort. Special acknowledgment goes to the International Advisory Board for its significant input and constructive feedback. The Local Organizing Committee played a crucial role in preparing the conference, and I would like to thank you for your determination, commitment, and patience. Sincere thanks are also extended to all speakers and chairpersons for maintaining session schedules while encouraging lively debates. Gratitude is also expressed to the guest editors, authors, and referees for their dedicated efforts in ensuring that the proceedings accurately reflect the presented content. Special appreciation is reserved for Professor Jan Mostowski for his understanding, assistance, and support in preparing these proceedings.

The ongoing success of this symposia series fills me with optimism and eager anticipation for the forthcoming event in 2025. I hope that the Zakopane School of Physics 2023 has made a meaningful contribution to fostering relationships within the community engaged in interdisciplinary research, transcending the traditional boundaries of physics and biology.

Magdalena Fitta

Chair of the Conference

The  paper of  the  month,  chosen  by  the Editor-in-Chief,  is  "Unusual Strain Resulted from InteractionBetween Permanent Magnets"  by V.I. Nizhankovskiy;

DOI: 10.12693/APhysPolA.145.57

Everybody is familiar with permanent magnets. Small, very strong permanent magnets are used in many devices, from toys to advanced electronic systems. This paper studies basic physical processes taking place in such magnets.

When a magnet is placed in a magnetic field, e.g. in the vicinity of another magnet, magnetic forces lead to stress forces and hence to deformation of the magnet. These deformations were studied in this paper. Experiments were done with cylindrical NdFeB magnets. Magnetostriction and elastic parameters of the magnet, namely the Young modulus and the Poisson ratio, were measured. Also the magnetic field distribution around the magnet was determined. The results of these investigations were used to predict the strain of the NdFeB magnet as a function of the magnetic field. All these experiments were nicely interpreted in the framework of the theory of elasticity. Thus a complete picture of processes taking place in permanent magnets is given.

Everybody who wants to learn what is going on when two strong magnets are placed close to each other should read this paper.

The Editor-in-Chief

The  Special Issue in Memory of Professor Marek Cieplak (1950–2021)

Marek Cieplak, born December 8, 1950, passed away on December 31, 2021. He was a Professor of Physics, a lecturer of summer courses in physics at Rutgers University and Johns Hopkins University in the USA, a member of the Scientific Council of the Institute of Physics of the Polish Academy of Sciences (PAS), initiator of biophysical topics at the Institute of Physics PAS, founder and head of the Laboratory of Biological Physics, spiritus movens of the series of international scientific conferences "Biomolecules and Nanostructures", member of scientific societies and editorial boards of scientific journals such as Journal of Physics: Condensed Matter and Acta Physica Polonica A.

Marek — as a student — got involved in helping Professor Białynicki-Birula to prepare notes for his lecture on quantum mechanics. These notes eventually evolved into a book, which Marek co-authored with Professor Białynicki-Birula and Professor Jerzy Kamiński, many years later. Photos taken from the family resources with permission.

• The special issue collects several articles that aim to symbolically commemorate Marek Cieplak, not only because of his profession. All articles went through the peer review process, and the authors and reviewers deserve thanks.


• The unusual and unique feature of this issue is not only its scientific content, but also the inclusion of several personal recollections. Below are short texts about Marek, as he is remembered by colleagues, former PhD students (now full-fledged scientists) and his friends. The editors appreciate their presence and sharing! It is worth reading these personal recollections because they outline the broader profile of Marek, his human qualities for which he was appreciated. 

The Editors

Marek Cieplak was a man full of passion — both in physics and beyond. You could feel the strength of his personality already as you approached his office, which stood out against the gray and somewhat colorless corridors of the Institute of Physics of the Polish Academy of Sciences — the door was always open, and inside it was filled with flowers, paintings, posters, and figurines. Once you stepped in, Marek would tear himself away from his inseparable computer and bombard you with a vast number of scientific ideas, intertwined with the latest cultural curiosities, books he had read, movies he had seen, or travels, which he was passionate about. Marek's research was just as eclectic — from work on spin glasses, to the analysis of river networks, optimal paths in disordered systems, fluid invasion into the porous media, and the microscopic origins of friction. In the last 25 years, his main focus has been biological physics, in particular numerical models of protein folding and unfolding, interpretation of genetic microarray data or knots and entanglements in biomolecules. We collaborated on many of these subjects, publishing 15 papers together. 

I will miss his energy, passion, and drive to keep moving forward. I am grateful for the time we shared and for the inspiration he brought to our work.
 

Piotr Szymczak

Professor Marek Cieplak, as we all know, was an extraordinary character, a person who always had his own opinion, always had substantive arguments and was able to defend them to the end. This was also Marek's whole life...  and this state of mind was contagious to others — to me certainly. I had the pleasure of being a doctoral student of Professor Cieplak. Marek's knowledge and behavior had a huge impact on my scientific career and on my decision to follow this path. Marek was 110% committed to every doctorate, and he demanded the same! He was at work every day, he came every day to talk about both science and life. His room at the Institute of Physics was full of flowers, paintings and souvenirs brought from his travels around the world, as well as two sports items: a tennis racket and a bicycle. Marek cycled to work whenever he could. His wife and daughters painted the paintings. This room looked like a real museum — it always encouraged me, even when Marek asked rhetorically: "Why don't computers count when it's cold outside, or why don't I have the conscience to freeze them like that?" He did it jokingly, but you could still feel a shiver of fear. Yes, he definitely made sure that the learning progressed and that every moment was well-planned and used. I remember well that before I left for trekking in the Himalayas, he made sure that I had a copy of my data and that I had planned the calculations appropriately so that the computers would not "freeze" during my 3-week trip. On the other hand, after returning I saw how happy he was, not only that the data had been calculated, but that I had returned in one piece. Marek was caring; he was hot-tempered, but he always meant well and strived for objective truth. 

From a scientific point of view, I think it should be strongly emphasized that the topic of non-trivial topology in proteins, which I continue to develop (as do a lot of scientists around the world), was born by accident, but this accident was created by Marek. One day in 2006, just before the holidays, Marek came up with the idea to determine the free energy landscape of proteins from the point of view of mechanical resistance. This idea probably resulted from the fact that at that time single-molecule optical tweezers, which trapped micron-sized silica beads (of diameter range of 0.2-5 m) to exert forces on the system of interest, achieved very high precision in measurements, showing that titin (the protein that makes up our muscles) has a mechanical resistance of about 210 pN. On the other hand, the mechanical resistance of the calcium-binding C2A protein has been found to be much weaker, i.e., the peak force is only of order 60 pN. Marek's goal was to learn the limits of the mechanical strength of proteins and to understand whether this feature correlates with the biological function or perhaps the spatial structure of proteins. 

The idea was brilliant (more on that below), but what was worse, Marek wanted to do it in his own style, i.e., as best as possible. That meant writing a program to stretch (possibly in many direction) all known protein structures deposited in the Protein Structure Database in 2006. At that time, there were over 50 000 structures. This idea was in the style of current big data, although such an approach was not yet used at that time. Marek always did things ahead of his time. So the man had to bite the bullet and rise to the challenge. The idea was also very successful from the point of view of the so-called Go-like model, which Marek created with his PhD student (Professor T.X. Hoang). In the Go-type model that Marek used, two factors played a major role: native contacts (defined based on the geometry of the protein in its native state) and the spatial structure of the protein (alpha-helices, beta hairpins). Therefore, the model performed is ideal for studying mechanical properties, starting from the native structure of the protein. After 6 months of research, it was possible to find proteins whose resistance force was over 1000 pN. It turned out that among these proteins there were proteins with non-trivial topology knotted proteins. Our first reaction was that this must be a mistake — none of us knew or expected knots in the proteins to exist.

There are proteins that show such high mechanical resistance. However, proteins with non-trivial topology show lower resistance, and in such a case the observed force comes from the knot tying, but thanks to that, we were able to find them. Today, the study of non-trivial topologies in proteins has become a separate, dynamic research field at the intersection of biophysics, biochemistry, and mathematics. Marek's works are among the best cited on this topic, and a collection of his works forms the basis of a review entitled "Topology in soft and biological matter" published this year in Physics Reports 1075, 1 (2024).

Joanna Sułkowska

The outstanding role that Professor Marek Cieplak played in theoretical physics, condensed matter physics, and biological physics is beyond dispute. However, I personally believe, and I would like to emphasize, that all these achievements were possible thanks to his exceptional personality.

Marek was a visionary, an inspirer and a titan of hard work, constantly seeking new inspirations with tireless energy, determination and scientific passion, along with many humanistic interests. He was always on the lookout for scientific developments, driven by the energy and determination to bring ideas to fruition. The word that best describes Marek is "passion" and he embodied this spirit, as lively and tireless as a great fire.  

Marek had one mantra that he often repeated and consistently implemented: "Don't give up without a fight!" This was his Golden Thought. He always took the bull by the horns. I remember him as a person for whom nothing was too difficult to at least try. That is why he had a remarkable ability to motivate colleagues to push beyond their limits.

He was the initiator of introducing biological physics at the Institute of Physics of the Polish Academy of Sciences. Fueled by Marek's enthusiasm and determination, in 2004 we began our activity as a small Biological Physics Group SL-1.5. Our first challenge was to secure funding and set up experimental laboratories. We acquired space in an old transformer station and storage area at our Institute, where I started building laboratories equipped with the essentials to commence experimental work, with great support from Marek. Over time, many people joined the group, new topics emerged, including nanotechnology, and our group was upgraded to the Laboratory of Biological Physics SL-4. However, we still needed significant changes and investments, as our initial setup was quite basic.

I must emphasize that Marek's tireless enthusiasm for taking on risky initiatives was one of the strongest motivational impulses I have ever experienced. I am certain that the energy derived from daily interactions with Marek was vital in undertaking such ambitious projects. It ultimately led me to establish a consortium to create seventeen new laboratories in Poland, including our own microspectroscopy laboratory and a second computer cluster for Marek's group within the POIG ERDF NanoFun Project. 

One of the most significant contributions by Marek to sharing high-level science with society is the "Biomolecules and Nanostructures" (BioNano) conference series. Marek envisioned this event as an opportunity for scientific friends to meet and discuss topics in an informal atmosphere. It resembled a group retreat, yet extended to around one hundred participants in a secluded area, far from large cities. The great success of these conferences stemmed from the fact that Marek's friends and collaborators from all over the world came together to meet him in person. He deeply valued his scientific friendships.

Over the years, we have transformed the meeting from an extended group retreat called the "Workshop on Structure and Function of Biomolecules" (2004, 2006) into an international scientific conference series "Biomolecules and Nanostructures" (2011, 2013, 2015, 2017, 2019), while maintaining the informal character of the meetings. The broader framework of the BioNano conferences also aligned with Marek's further involvement in nanobiotechnology studies. The venues changed, always close to nature and often in spartan accommodation, but the priority was still on the quality of the lectures and scientific discussions, fostering connections and collaboration among attendees rather than focusing on comfort. The conference grew, and Marek remained close to and engaged with the participants.  

The great added value of the BioNano conferences lay in crossing barriers between the exact and natural sciences and the humanities — this was interdisciplinarity and multidisciplinarity in the best sense of the word. The opening lectures led the audience from linguistic methodology to molecular biology and from fundamental physics to physiology and evolution. This was made possible because, in addition to his great commitment to scientific matters, Marek moved us with his humanistic sensitivity. He often noticed little things that helped us feel more integrated with the world.  

Marek was also always accompanied by his family. It was truly remarkable that despite his immense commitment to his professional career, he always maintained close ties with his loved ones.  

Professor Marek Cieplak exemplified a rare combination of great ambition and versatile competencies, constantly seeking new inspirations. I remember him sitting in his armchair, going through the latest issues of Nature or Science, selecting topics that were new to him and to which he could apply the methods he had developed in order to join a new field.  

Marek was always "on the ball", catching everything and hitting the mark. He will remain in my deepest memories.  

Anna Niedźwiecka

The 11th Workshop on Quantum Chaos and Localisation Phenomena was held in Warsaw, Poland, on May 25–26, 2023, at the Institute of Physics of the Polish Academy of Sciences. Although the end of the COVID-19 coronavirus pandemic was announced, due to its long-lasting effects and existing threats, the meeting was again fully virtual and took place on the ZOOM platform. The Workshop was organized by the Institute of Physics of the Polish Academy of Sciences, the Center for Theoretical Physics of the Polish Academy of Sciences, and the Foundation "Pro-Physica". The first of these biennial workshops was organized in 2003. Selected articles from the invited lectures, starting from the second Workshop, were published in Acta Physica Polonica A [1–9]. The main objectives of the Workshops are to assess achievements and formulate directions for new research on quantum chaos and localisation phenomena.

The Workshop gathered 30 officially registered participants from Afghanistan, China, the Czech Republic, France, Germany, Israel, Poland, Sweden, the United Kingdom, and the USA, representing experimental and theoretical physicists. Additionally, about 20 participants, mainly Ph.D. students and doctors, had the opportunity to join the Workshop via the ZOOM platform. The lectures were also attended by non-registered researchers and Ph.D. students of the Institute of Physics and the Center for Theoretical Physics on the Institute's YouTube channel. During the meeting, 18 invited lectures and 3 posters were presented. The presentations focused on the following topics: quantum chaos and non-linear classical systems, quantum and microwave graphs and billiards, localisation phenomena, topological effects, and physics of low-dimensional systems. In talks and poster presentations, theoretical and experimental problems from various fields of solid state, atomic and molecular, mathematical and statistical physics were discussed. It is noteworthy to mention that although most of the lectures were devoted to the theory of quantum chaos and many-body systems, there were also very interesting new topics, such as topological effects, chiral ensembles, and — for the first time — applications of chaotic systems to modelling metamaterials. The meeting was held online, so scientific discussions that traditionally took place during coffee breaks and social events, this time took place between lectures and during visits to the "rooms" where the posters were displayed.

On behalf of the organizers, we would like to express our gratitude to all the speakers and the authors of poster presentations for their contribution to the success of the Workshop.

We present Proceedings of the 11th Workshop on Quantum Chaos and Localisation Phenomena, in which 11 invited articles of the Workshop participants are published.

The workshop organizers acknowledge the financial support of the Ministry of Education and Science under the program "Doskonała nauka II" under the contract KONF/SN/00702023/01.

Szymon Bauch
Leszek Sirko

Editors of the Proceedings

[1] L. Sirko, S. Bauch, Acta Phys. Pol. A 109 (1), (2006)

[2] L. Sirko, S. Bauch, Acta Phys. Pol. A 112 (4), (2007)

[3] L. Sirko, S. Bauch, Acta Phys. Pol. A 116 (5), (2009)

[4] L. Sirko, S. Bauch, Acta Phys. Pol. A 120 (6-A), (2011)

[5] L. Sirko, S. Bauch, Acta Phys. Pol. A 124 (6), (2013)

[6] L. Sirko, S. Bauch, Acta Phys. Pol. A 128 (6), (2015)

[7] L. Sirko, S. Bauch, Acta Phys. Pol. A 132 (6), (2017)

[8] L. Sirko, S. Bauch, Acta Phys. Pol. A 136 (5), (2019)

[9] S. Bauch, L. Sirko, Acta Phys. Pol. A 140 (6), (2021)

The works included in this special issue were presented during the fourth edition of the international scientific conference "Application of Physics in Mechanical and Materials Engineering" — APMME 2023. This conference took place on June 29, 2023 in Częstochowa. The conference was organized, as usual, by the Department of Mechanics and Fundamentals of Machine Design at the Faculty of Mechanical Engineering and Computer Science at the Czestochowa University of Technology. This year, the scientific meeting of APMME was held in conjunction with the International Exhibition of Innovation — IEI 2023. The honorary patronage over the conference and exhibition was taken by the Rector of the Czestochowa University of Technology, Professor Norbert Sczygiol. 

On behalf of the Scientific and Organizational Committee of the APMME 2023 conference, we would like to thank the Rector of the Czestochowa University of Technology for his honorary patronage over the conference. We would also like to thank the Dean of the Faculty, Professor Małgorzata Klimek, for significant help in organizing the conference. Our warm words of thanks go to all participants who kindly responded to the invitation of the Organizing Committee of the APMME 2023 conference. We would like to express our special thanks to the keynote and invited speakers. 

The APMME conference has been an international conference for two years and has become a permanent fixture in the calendar of important conferences in our country. During the meeting, participants from Poland and abroad could present and discuss the latest achievements in the field of broadly understood applications of physics in mechanical and materials engineering. Over seventy participants from Poland, Bulgaria, Canada, China, Czech Republic, India, Malaysia, Romania, Taiwan, and Turkey have registered for the APMME 2023 conference. Participants presented their works at plenary sessions and in a poster session. The conference papers submitted to the Scientific Committee were reviewed and sent for approval to the Publishing Team of Acta Physica Polonica A.

The Guest Editors would like to thank the Editorial Staff for their effort and help in preparing this issue.

Wojciech Sochacki
Sebastian Garus
Marcin Nabiałek
Paweł Kwiatoń

Guest Editors

The  paper of  the  month,  chosen  by  the Editor-in-Chief,  is  "Micro and Nanocrystalline LuPO₄(Ln³⁺: Nd, Pr) —Morphology, Luminescence and Inter-ionic Interplays"   by  O. Bezkrovna, P. Zdeb, O. Bezkrovnyi, R. Lisiecki, and P.J. Dereń;

DOI: 10.12693/APhysPolA.144.263

In recent years nanomaterials have been studied extensively because of their broad range of possible applications. One of the areas of applications is in biology and biomedicine, where optically active nanomaterial materials are of special interest since they provide the possibility of building various sensors. The authors of this paper studied lutetium phosphate nanoparticles, the choice of phosphates was based on their low toxicity. Also, these nanoparticles can be used as stable matrices for the introduction of luminescent ions. The paper describes the optimized synthesis process of nano- and micro-sized luminescent LuPO₄ materials and their doping with Pr³⁺ and Nd³⁺ ions. Furthermore, selective excitation of Pr³⁺ and Nd³⁺ ions in co-doped materials is investigated and the luminescence properties of synthesized materials are studied. The physical mechanism of the luminescence process is investigated by the authors.

The paper presents high-level research in the subject of synthesis and photophysical and physicochemical investigation of optically active inorganic nanomaterials. I recommend it to all readers interested in nanotechnology and the physics of nanomaterials.

The Editor-in-Chief

The  paper of  the  month,  chosen  by  the Editor-in-Chief,  is  "On Weyl Nodes in Ferromagnetic Weyl Semimetal"   by  U.P. Tyagi and P. Goswami;

DOI: 10.12693/APhysPolA.144.197

Crystals with non-trivial topological properties are one of the most interesting and intensively studied systems in condensed matter physics. Weyl semimetals are one of them. They are not only interesting from the point of view of basic physics but also it is expected that they can be used in fast electronics. In the present paper a simple model of ferromagnetic Weyl semimetal is studied. In spite of being simple, the model takes into account all essential ingredients of such systems: the tunneling effect, exchange field leading to ferromagnetism, chirality of the Weyl nodes and the shift of the nodes. The presence of the Weyl points of opposite chirality has been shown in the band structure. Also the Berry curvature and the anomalous Hall conductivity have been found. In addition, it has been shown that interaction with light can change the topological states, this can even lead to emergence of a novel phase with broken time reversal symmetry. This relatively simple model shows a variety of nontrivial properties that can exist in crystals. The present paper significantly broadens our knowledge about these important modern materials.

The Editor-in-Chief

The  paper of  the  month,  chosen  by  the Editor-in-Chief,  is  "Application of Polarizing Optical Microscopy   in   Investigation  of  Crystallization   Kinetics  from  Smectic  C^∗_A  Phase"   by  A. Deptuch, A. Lelito and M. Urbańska;

DOI: 10.12693/APhysPolA.144.93

Liquid crystals are a very interesting class of materials exhibiting a variety of unexpected physical properties. Although studied for over one hundred years their properties are still not fully explored. The present paper deals with the crystallization process, both isothermal and non-isothermal of a compound, which exhibits the smectic synclinic C^∗ and smectic anticlinic C^∗_A phases. With the help of polarization microscopy the authors found a large hysteresis, in the phase transition between the two phases. This phase transition is shifted during cooling almost below the melting temperature of a crystal phase. Thus, the studied compound is an example of liquid crystalline mixtures that exhibit the vitrified syn-clinic Sm C^∗ phase instead of anti-clinic Sm C^∗_A.
In a nice experiment the authors show one more example of complexity and also the beauty of liquid crystals.

The Editor-in-Chief

The paper of the month, chosen by the Editor-in-Chief, is "Investigation of the Teapot Effect" by Ali Kibar;  

DOI: 10.12693/APhysPolA.144.26

Physics is not only about abstract things or exotic materials, physics helps to understand every-day effects as well. Some of such effects can easily be explained, some others are rather hard. Spilling liquid from a teapot is one of such hard everyday effects. It is generally known that sometimes the liquid flowing out of a spout adheres to the outer part of it instead of flowing directly downwards. This is the teapot effect discussed in the paper.

The effect is not easy to explain since many factors contribute to the behavior of the liquid flowing out of a spout. Liquid viscosity, capillary adhesive force, ambient pressure are among the most important factors that determine the character of the flow.

All relevant hydrodynamic effects are considered in this paper. Physical analysis led to hydrodynamic equations that were solved numerically on a huge mesh. The results are illustrated by experiments with liquids flowing out of teapots having spouts covered by hydrophobic and hydrophilic surfaces. I enjoyed the experimental part of the paper – photographs of a liquid pouring out of a teapot illustrate well many aspects of effects taking place.

I strongly recommend reading this paper, I enjoyed the application of advanced physical methods to discuss an every-day effect.

The Editor-in-Chief

Preface 

In 1952, an unknown student from the Mechanical Technical High School in Rzeszów, a provincial city, took first place (along with two other participants) in the First Physics Olympiad – a prestigious contest organized by the Polish Physical Society. Apart from the great splendor that befell this young student, the victory allowed him to avoid mandatory (due to the regulations of that time) employment in one of the local factories and opened the route for him to study at the University of Warsaw. There, he quickly came under the guidance of outstanding theoreticians led by Professor Leopold Infeld. This is how the successful scientific career of Professor Iwo Białynicki-Birula began, as well as that of all his students and collaborators, who for decades have been continuously drawing on his incredible intuition, brilliance, and kindness. Just as physics and the world have been changing over the past 70-years, the memories of his students who came under his mentorship are surely diverse. However, what definitely unites them all is the belief in the incredibly profound physical intuition of Our Professor, which he constantly expresses in one of his most beloved sayings: Przyroda jest łaskawa (eng. Nature is kind). Indeed, striking is his readiness to undertake risky and sometimes slightly controversial research directions. Who else, if not the Professor, would have dared to question the validity of the widely used Feynman's proof [1] or to construct a consistent formulation of a nonlinear correction to, by definition linear, quantum mechanics [2, 3]? Only the Professor and his wife, Professor Zofia Białynicka-Birula, could envision and later prove that photons can undergo splitting in an external magnetic field [4] or that the uncertainty principle, similar to that of massive particles, can also be formulated for quanta of light [5, 6]. Once, for purely bureaucratic reasons, I asked the Professor what I should put in the "scientific interests of the supervisor" section of a certain form. Without hesitation and with full conviction he answered: Theoretical Physics. Although quantum electrodynamics is his greatest passion, his horizons extend to all corners of contemporary physics, where he always finds interesting questions that are still awaiting answers.  

On the occasion of Professor Iwo Białynicki-Birula's 90th birthday, I invite everyone to read this special issue of Acta Physica Polonica A, in which his students, collaborators, and friends publish scientific papers from their respective fields of expertise. The richness of the topics covered and references to the Professor's scientific activities once again demonstrate how versatile and respected a scientist he is.

Happy Birthday, Master!

Guest Editor:

Tomasz Sowiński

Bibliographic information regarding the Special Issue

Title: Acta Physica Polonica A: Special issue in honor of scientific achievements of Professor Iwo Białynicki-Birula on his 90th birthday

Guest editor: Tomasz Sowiński

Publisher: Institute of Physics of the Polish Academy of Sciences

Volume: 143             

Number of pages: S1-S200             

Publication date: 2023                

Doi: 10.12693/APhysPolA.143.S0

The paper of the month, chosen by the Editor-in-Chief, is "Estimation of Jiles-Atherton Parameters of Toroidal Cores using MATLAB/Simulink" by Š. Gans, J. Molnár, D. Kováč;  

DOI: 10.12693/APhysPolA.143.389

A ferromagnetic toroidal core of iron powder was studied experimentally and numerically. Hysteresis loops, major and several minor ones were detected and measured with the help of a special setup. A genetic-type algorithm was developed and used to fit parameters of a model of ferromagnetic hysteresis. Experiment and theory supported by numerical modelling lead to a proper description and deep understanding of complicated processes that take place in the studied magnetic material.

The Editor-in-Chief

The paper of the month, chosen by the Editor-in-Chief, is "Role of Multi-Walled Carbon Nanotube Addition in Superconducting Properties of Bi_{2}Sr_{2}CaCu_{2}O_{8+s} Glass–Ceramic Superconductors" by K. Yakinci and Ö. Çiçek;

DOI:10.12693/APhysPolA.143.298

High-temperature superconductors play an important role in various areas of physics and technology. One of the directions of improving the quality of these materials is the creation of artificial defects, e.g. by doping. In this way, the value of the critical current can be increased. In this paper, the authors prepared the samples by the conventional glass–ceramic route. They showed that the addition of carbon nanotubes can change the critical current density by up to about 30% without significant morphological change of the material. This research makes a step forward toward better superconductive materials.

The Editor-in-Chief

The 20th National Conference on Superconductivity "New Phases, Concepts, and Advances" was held in Lublin from 22nd to 26th May 2022 as a fully in-person event. The conference was organized jointly by Marie Curie-Skłodowska University, the Lublin Branch of the Polish Physical Society, and the Technical University of Lublin. Former conferences in this series were devoted initially to high-temperature superconductivity and later on, they have included several related phenomena, for example: colossal magnetoresistance, strongly correlated systems, spin and charge ordering, unconventional superconductivity, and other emergent phenomena.

This Conference focussed on topics such as high-temperature superconductors and other highly correlated systems, synergy of magnetism with superconductivity in hybrid structures, critical phenomena in superconductors and superfluids, exotic quasiparticles in topological states of matter, dynamic effects in non-equilibrium superconducting structures, and applications of conventional and unconventional superconductors. The Conference was attended by 76 participants. The opening talk was delivered by Professor Wiesław I. Gruszecki, Vice-Rector of M. Curie-Skłodowska University, who addressed important aspects concerning the retina of the human eye (Dlaczego warto zadbać, aby żółta plamka w naszym oku była naprawdę żółta). Three plenary lectures were delivered by the Professors: Józef Spałek (A brief perspective in high temperature superconductivity), Marta Z. Cieplak (Interplay of various order parameters and disorder in iron chalcogenides), and Tomasz Dietl (Exchange interactions in magnetically doped semiconductors). Also, 20 invited lectures, 23 brief contributed talks, and 23 posters were presented. The list of all presentations, along with their abstracts and a detailed time-frame, is available on the conference webpage (see sites.google.com/view/kkn2022).

We would like to thank all the attendees for their participation and for creating an exciting scientific atmosphere during the Conference. The next event of this series will be organized by colleagues from Cracow.

Tadeusz Domański
Nicholas Sedlmayr
Karol I. Wysokiński

Guest Editors

The paper of the month, chosen by the Editor-in-Chief, is "In-Plane Optical Anisotropy of [001]-Oriented Asymmetrical Quantum Wells" by Djanelidze and E. Tsitsishvili; 

DOI:10.12693/AphysPolA.143.30

Despite of the fact that the optical anisotropy in quantum wells has been investigated theoretically and experimentally for many years the authors present an interesting theoretical approach to calculating optical anisotropy in asymmetric quantum wells. The analysis starts from basic symmetry considerations that lead to the appearance of anisotropy caused by asymmetry of the quantum well. Next the formulated model is applied to the in-plane optical anisotropy of [001] zinc blende quantum wells. It is shown that the asymmetry should result in the mixing of light- and heavy hole states. The paper contributes to the understanding of the role of symmetry breaking in quantum wells.

The Editor-in-Chief

The papers included in this volume of Acta Physica Polonica A are a contribution to the XIII International Conference on Ion Implantation and Other Applications of Ions and Electrons ION 2022, which was held in Kazimierz Dolny, Poland, on June 27-30, 2022. The Conference was organized by Maria Curie-Skłodowska University in Lublin in cooperation with the Lublin University of Technology and the Polish Physical Society.

The Conference was attended by 44 participants from Belarus, Germany, Poland, South Africa, and Ukraine, who had the opportunity to meet in a friendly atmosphere in the beautiful historic town of  Kazimierz Dolny to exchange experience in the eld of ion implantation and the application of electron beams and plasma. The idea of the biennial ION Conferences was stimulated by the permanent interest in ion beam methods, which started from fundamental studies in ion and plasma physics and have established themselves as the standard techniques for material modication and characterization. A wide range of topics was addressed during the ION 2022 Conference, including inter alia: ion beam modication of semiconductors, metals, insulators, and polymers, microstructural investigations of ion-implanted and swift heavy ion-irradiated materials, tribological properties of metallic and ceramic plasma-deposited coatings, computer simulations of post-implantation damage and ionization processes in ion sources. The diversity of topics was a great advantage for the participants of the Conference because it oered new approaches to solving scientic and technological problems.

During the four days of plenary sessions, 14 invited talks and 2 special lectures were given, reviewing actual topics of interest to the participants. The ION 2022 Conference also featured 13 oral presentations and 27 poster contributions with detailed information. Nine persons participated in the Young Scientists Contest.

We would like to thank everyone who contributed to the organization of our Conference in the dicult year of 2022. Special thanks are due to Mr. Janusz Filiks, Dr. Andrzej Droździel, and Dr. Krzysztof Pyszniak for their work, as well as to Dr. Wolfgang Skorupa for giving us a traditional organ concert in the Fara church in Kazimierz Dolny.

Guest Editor:

Marcin Turek
Jerzy Żuk

This issue of Acta Physica Polonica A includes some of the presentations given at the 50th International School & Conference on the Physics of Semiconductors “Jaszowiec 2022”. The program of this jubilee event was special. In addition to regular sessions, it included a reminiscence session on the most  important achievements in the field of semiconductor physics over past years in the institutions organizing the Conference, which are:

• Institute of Physics of the Polish Academy of Sciences,
• Faculty of Physics (Institute of Experimental Physics and Institute of Theoretical Physics), University of Warsaw,
• Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology,
• Institute of High Pressure Physics of the Polish Academy of Sciences,
• Łukasiewicz Research Network — Institute of Microelectronics and Photonics.

The program also included a session devoted to the history of two companies that developed key semiconductor technologies in Poland, i.e., VIGO Photonics and AMMONO. As every year, outstanding world experts in the broad field of semiconductor physics, working both in foreign research centers (51 participants from 19 countries) and in Poland (211 participants from 11 scientific institutions and 8 companies), took part in “Jaszowiec 2022”. The topics of the Conference focused mainly on semiconductor nanostructures, two-dimensional (2D) materials, topological states of matter, spintronics, nanophotonics, quantum computing and quantum information processing, synthesis and characterization of semiconductor materials and electron devices. The Tutorial Session (School), addressed mainly to MSc students, PhD students, and young scientists, traditionally preceded the Conference, and this year it covered the subjects of 2D materials, quantum bits, non-linear spectroscopy, and photovoltaics.

We would like to express our gratitude to the members of the Program and the Advisory Committees for their wonderful work and contribution to the success of the jubilee “Jaszowiec 2022”. The most heartfelt thanks go to Anna Reszka and the Organizing Committee led by her, who made “Jaszowiec 2022” run smoothly and retain its magical atmosphere of a friendly scientific meeting. We also address special acknowledgments to Tomasz Jakubczyk, chairman of the Tutorial Session.  Finally, we would like to thank all the sponsors of the Conference: the Ministry of Education and Science, the Polish Academy of Science, the U.S. Army Combat Capabilities Development Command, and institutions organizing “Jaszowiec”, as well as commercial sponsors: COMEF, Technolutions, EDVAC, LABIS, Dr. Eberl MBE-Komponenten GmbH, and nextnano GmbH, for their financial and material support.

Guest Editors: 

Agnieszka Wołoś
Maria Kamińska
Aneta Drabińska

Dear Author, don't worry, all articles published so far in Acta Physica Polonica A can be found at ICM (Interdisciplinary Centre for Mathematical and Computational Modelling UW).

In addition, all articles are available at the National Library, Poland.