bluuebunny/crossref_metadata_2025 huggingface dataset:
Technology of obtaining liquid complex fertilizers in the presence of monoethanolamine based on phosphorites of the Central Kyzylkum
Authors: Sherkuziev Doniyor , Zokirov Solijon
Published: June 2023

The possibility of producing liquid fertilizers based on nitric acid processing of washed dried concentrate in the presence of monoethanolamine is shown. On the basis of nitric acid extract and monoethanolamine, liquid complex fertilizers with stimulating activity were obtained, composition: P2O5tot. - 10-11%, CaOtot. - 6-7%, Ntot. 12-13% and K2O-5-6%. They contribute to the acceleration of plant growth by 10- 12 days and an increase in yield by an average of 8-10% compared to the control variant. It can be concluded that they can be recommended as liquid complex fertilizers for drip application.
Obtaining swelling hydrogels to improve fertility and the benefit of retaining sandy soils
Authors: Akhmedov Ulug , Tanatarov Otkirbay , Usmonova Aziza , Abramatov Makhamadi
Published: June 2023

The article provides information on the preparation of polyelectrolytes and swelling polymeric hydrogels with different specified properties. The analysis of domestic and foreign scientific literatures is presented. Particular attention of researchers is paid to rare cross-linked polyelectrolytes, the so-called supermoisture absorbents or hydrogels. Thanks to a complex of variable unique properties, supermoisture absorbents have found the widest application on the world market in medicine, industry, agriculture, and in solving water and environmental problems.
Methods for determining the rate of corrosion with the application of a corrosion inhibitor produced on the basis of secondary raw materials
Authors: Panoev Erali , Dustov Khamro
Published: June 2023

This article describes the synthesis technology of a new corrosion inhibitor based on formalin, thiosemicarbazide, and orthophosphoric acid, as well as the method of determining the corrosion rate of the synthesized corrosion inhibitor by polarization resistance and gravimetric method. The effectiveness of the synthesized corrosion inhibitor against corrosion caused by the acid in the mixture of gases from mines in gas treatment plants has been reflected in the results of research and testing. Also, the effectiveness of the corrosion inhibitor and the braking coefficient were determined.
Development of environmentally sustainable solutions to provide greenhouse production with alternative energy
Authors: Dolgikh Pavel P.
Published: June 2023

The paper presents scientific and technical solutions to improve the efficiency of greenhouse irradiators used in growing plants in the light culture of industrial greenhouses. The author's technology is described, which makes it possible to regulate the energy flows of the irradiation system during the growing process. The results are given that determine the rational temperature range of the air flow 32÷38°С, created by a greenhouse irradiator, for the needs of heating an industrial greenhouse. It has been established that a decrease in the lamp temperature in the voltage range on the greenhouse irradiator of 198÷220 V for every 1°C leads, on average, to an increase in the PAR value by 2.5 mW/cm2. Dependences of the radiation force distribution as a function of the air flow velocity and PAR as a function of the lamp temperature are obtained. The regularities of influence of network operation modes and lamp temperature on the efficiency of the irradiation system as a whole are determined. Taking into account the experimental data obtained, a technological scheme of irradiation in an industrial greenhouse was developed and the principle of its operation with a greenhouse irradiator with a forced cooling function was described.
Evaluation of the degree of shredding and granulometric composition of roughage by the disk working body of the shredder
Authors: Tumanova Marina , Kotelevskaya Elena , Zhigailov Fedor
Published: June 2023

The article discusses theoretical and experimental studies of the evaluation of the degree of shredding and granulometric composition of roughage by the disk working body of the shredder. The article gives a constructive-technological scheme of a shredder with a disk working body. The paper also presents the results of the research.
Energy-efficient asynchronous electric drive as a means of increasing the reliability and energy efficiency of pumping plants in the urban water supply system
Authors: Pulatov Abror , Shamiev Murat , Mirsaidov Ulugbek
Published: June 2023

The article discusses the issues of improving energy efficiency and reliability of the pumping plant for buildings and structures’ water supply. An example of the operation of a pumping plant energy-efficient asynchronous electric drive is given. The optimal pump control algorithms are considered.
Distribution of fish in the subarctic lake
Authors: Chemagin Andrey A.
Published: June 2023

The paper studies fish population of an isolated lake in the subarctic zone. The study of the features of distribution of fish, the assessment of their abundance and size structure were carried out by the echometric method using hydroacoustic complexes and geoinformation systems. The research found out that the fish population is represented by 4 species of fish: roach, perch, pike and peled, with the absolute dominance of cyprinids. Their share of the total number of fish in the reservoir was >80%. Features of the horizontal distribution of fish are mainly due to trophic-defensive behavior (concentration of juveniles in the littoral), where it is possible to use macrophytes as shelters from visually oriented predators - perch and pike. In the horizons of the water column with depths <5 and >5 m, 72.4 and 27.6% of fish from their total abundance in the reservoir were recorded, the average density of fish at the considered horizons was 2149 and 398 ind. / ha. In the vertical aspect, the distribution of fish is determined by both trophic-defensive (concentration of juveniles in the littoral) and thermoregulatory behavior (concentration of peled on the drope of depth in the profundal zone).
Urbanization as an ecological phenomenon
Authors: Lomskov Mikhail A. , Pimenov Nikolay V. , Ivannikova Regina F. , Konovalov Alexander M. , Tishchenko Alexander S.
Published: June 2023

In this article authors discuss the main ecological aspects of the urbanization process. In particular, such phenomena as anthropogenic transformation of the environment, which is the basis of all further transformations forming urban areas, are analyzed. In addition, the processes of anthropogenic change of organisms, for example, cultivation and domestication, are considered. Unfortunately, in modern science, the process of urbanization is usually considered from economic, social, and cultural positions, often without affecting the environmental component. This fact is a significant omission, especially in the context of an increase in the number of natural landscapes transformed by human.
Diversity of the vegetation cover of the zone of potential influence of the Nizhneboguchanskaya HPP (Lower Angara region)
Authors: Krivobokov Leonid V. , Danilina Dilshad M. , Konovalova Mariya E. , Shestak Kira V. , Moskalchenko Svetlana A.
Published: June 2023

Active economic development of the Lower Angara zone requires the creation of a scientific basis for long-term monitoring of the state of natural ecosystems. The paper gives an assessment of the diversity of vegetation cover in the zone of potential influence of the Nizhneboguchanskaya HPP. An analysis of its typological structure on a landscape-ecological basis is given. The results of the DCA ordination and the interpretation of the leading axes of variation demonstrated the presence of four distinct groups of forest types that form ecological series according to the leading factors - the richness and hydrothermal regimes of soils. The dendrogram of forest types in the study area reflects the floristic integrity of the identified groups of forest types and the floristic relationships between them.
Intracenotic patterns in damage of Abies sibirica Ledeb.-dominated stands by infectious diseases in the south of Central Siberia
Authors: Melnichenko Natalia , Tatarintsev Andrey
Published: June 2023

Abies sibirica Ledeb.-dominated stands degradation is of special concern. Nevertheless, insufficient attention is paid to the role of pathogens in this process. The aim of the present study is to assess the coenotic role of infectious diseases in fir-dominated stands in the south of Central Siberia. The research was based on a forest pathological examination conducted in A. sibirica-dominated forest stands in the Krasnoyarsk Krai. The cenotic role of the identified diseases is unequal. Stem decay and fir broom rust are typical diseases that weaken trees and induce rotten windsnap accumulation. Fir broom rust randomly affects trees of different age and size. The prevalence of fir broom rust in the studied fir stands reached 10% or more. The most hazard diseases in the studied stands are bacterial soft rot and root rot. Bacterial soft rot damages up to 20% of trees and causes their gradual dieback. The main cause of tree mortality in fir-dominated stands is root rot. The root rot-causing fungi lead to rapid dieback of trees of different cenotic status. In synergy with other factors, root rot acts as a significant endogenous factor in the current reorganization of coniferous forest ecosystems in the south of Central Siberia.
Diversity of birds of prey belonging to the Accipitridae family in the eastern part of the Kugitang Range
Authors: Mamarajabov Saydmurot N. , Ochildiev Otabek Sh.
Published: June 2023

This article provides information on the study history, conservation measures, status, and meeting places of the birds of prey belonging to the Accipitridae family found in the eastern part of the Kugitang mountain. In the introduction, the relevance of the topic, the methods of research, and the results and discussion of the study of the researched predator species are described. Proposals for the protection of these species are given in the concluding part of the article.
Sign Language Interpretation using Ensembled Deep Learning Models
Authors: Khanna Samarth , Nagpal Kabir
Published: June 2023

Communication is an integral part of our day-to-day lives. People experiencing difficulty in speaking or hearing often feel neglected in our society. While Automatic Speech Recognition Systems have now progressed to the purpose of being commercially viable, Signed Language Recognition Systems are still in the early stages. Currently, all such interpretations are administered by humans. Here, we present an approach using ensembled architecture for the classification of Sign Language characters. The novel ensemble of InceptionV3 and ResNet101 achieved an accuracy of 97.24% on the ASL dataset.
An Object Detection Approach for Automated Detection of Groove Line in Tube Yoke
Authors: Kulkarni Uday , Naregal Kiran , Farande Vishal , Guttigoli Soumya , Angadi Apoorva , Ujwane Raunak
Published: June 2023

Deep Neural Networks are designed explicitly for visionbased applications. They have become a standard method for image classification, object detection, real-time processing capabilities, and other computer vision tasks. With the intervention of human beings, it is challenging for businesses to verify that the product is appropriately created without any glitches, as this could result in human errors due to a lack of training, which could further cause losses and several complications. Thus, there is a need for a machine learning-based solution that improves work efficiency and accuracy in identifying processed and unprocessed parts. Machine Learning models have several advantages over human intervention in tasks, including consistency, speed, scalability, costeffectiveness, and improvement over time. These advantages can help organizations improve their operations and achieve better outcomes. To do this, we propose an approach that involves building a model using an object detection method, You Only Look Once (YOLO), which is then deployed on a Raspberry Pi and integrated with the assembly line to carry out the task of validating the processed parts by achieving 98% accuracy.
Road Pothole Detection System
Authors: Lincy A. , Dhanarajan G. , Sanjay Kumar S. , Gobinath B.
Published: June 2023

A pothole is an open crack developed on roads owing to varied climatic situations and exposure to heavy-load trucks. Potholes are acting as one of the major causes of accidents and economic loss in the repair of vehicles. Hence this paper proposes a pothole detection system that assists drivers in avoiding potholes on the road by providing prior warnings using the YOLOV7 machine learning technique. The warning can be like a buzzer while the vehicle approaches a pothole. This concept can be expanded to create vehicles that detect humps and other road irregularities. The application depicted in this work effectively reduces the problem of increasing accidents caused by potholes by ensuring accuracy in real-time of about 94.5% at efficient complexity than state-of-art approaches.
Decentralized Malware Attacks Detection using Blockchain
Authors: Sheela S. , Shalini S. , Harsha D. , Chandrashekar V.T. , Goyal Ayush
Published: June 2023

This research introduces an approach to detect malware attacks using blockchain technology that integrates signature-based and behavioralbased methods. The proposed system uses a decentralized blockchain network to share and store malware signatures and behavioral patterns. This enables faster and more efficient detection of new malware files. The signature-based method involves storing the signatures in the blockchain and the sharing of the signature of malware files among the user nodes of the p2p blockchain network, while the behavioral-based approach analyzes the behavior and actions of files in a separate virtualized environment to identify suspicious patterns. This system addresses the limitations of conventional signature-based methods, which can be evaded by polymorphic malware, and behavioral-based methods, which may generate false positives. The results of the evaluation indicate that the proposed system achieves high detection rates while maintaining low false positives. Overall, the proposed system offers an effective and efficient approach to malware detection by utilizing the strengths of both signature-based and behavioral-based methods and utilizing the security and transparency benefits of blockchain technology.
Sehnenrupturen an der entzündlich rheumatischen Hand
– Bewährtes und Neues im operativen Umgang
Authors: Arnold Ingo
Published: June 2023

Die verbesserten medikamentösen Möglichkeiten einer nachhaltigen
Entzündungskontrolle hat im Bereich der Hand zu einem deutlichen
Rückgang notwendiger rheumaorthopädischer Operationen im
Zusammenhang mit Sehnenrupturen geführt. Ausgehend von einer
ungefähren Remissionsrate von 55–60% bei RA Patienten
besteht dennoch weiterhin die Notwendigkeit einer sorgfältigen Kontrolle
insbesondere auch der Sehnen im Bereich von Händen und
Füßen, auch weil einzelne Gelenke sich gegenüber
ansonsten systemisch gut wirksamen Remissionsinduktoren als
therapierefraktär erweisen können („rebellisches
Gelenk“). Durch eine Verbesserung primärer Sehnennahttechniken
z. B. durch eine Erhöhung der Anzahl an Kernnähten
(Stränge) haben sich auch bei Rheumapatienten die Möglichkeiten
einer direkten Reparatur optimiert. In der Mehrzahl der Fälle handelt es
sich allerdings um protrahierte Verläufe mit postprimären
Sehnenrupturen, sodaß die Defektsituation dann keine primäre
Naht mehr zuläßt und profunde Kentnisse im Umgang mit
Sehenkopplungs- und Transfertechniken erfordert. Im Bereich der
Beugesehnenchirurgie sollte der Rheumaorthopäde zukünftig von
den jüngeren Erfahrungen aus der Handchirurgie hinsichtlich neuer
Nahttechniken und frühfunktioneller Nachbehandlungskonzepte profitieren
können.
Expert Review on Contemporary Management of Common Benign Pleural Effusions
Authors: Porcel José M.
Published: June 2023

Heart failure (HF) and cirrhosis are frequently associated with pleural effusions (PEs). Despite their apparently benign nature, both HF-related effusions and hepatic hydrothorax (HH) have poor prognosis because they represent an advanced stage of the disease. Optimization of medical therapy in these two entities involve not only the use of diuretics, but also other pharmacological therapies. For instance, all HF patients with reduced or mildly reduced left ventricular ejection fraction can benefit from angiotensin receptor–neprilysin inhibitors, beta blockers, mineralocorticoid receptor antagonists, and sodium-glucose cotransporter 2 inhibitors. Conversely, it is better for HH patients to avoid nonselective beta blockers. Refractory cardiac- and cirrhosis-related PEs are commonly managed by iterative therapeutic thoracentesis. When repeated aspirations are needed, thereby diminishing quality of life, the insertion of an indwelling pleural catheter (IPC) may be warranted. However, in selected HH patients who are diuretic-resistant or diuretic-intractable, placement of transjugular intrahepatic portosystemic shunts should be considered as a bridge to liver transplantation, whereas in transplant candidates the role of IPC is debatable. Another benign condition, pleural tuberculosis (TB) is a serious health problem in developing countries. Diagnostic certainty is still a concern due to the paucibacillary nature of the infection, although the use of more sensitive nucleic acid amplification tests is becoming more widespread. Its treatment is the same as that of pulmonary TB, but the potential drug interactions between antiretroviral and anti-TB drugs in HIV-coinfected patients as well as the current recommended guidelines for the different types of anti-TB drugs resistance should be followed.
The Global Burden of Pleural Diseases
Authors: Vakil Erik , Taghizadeh Niloofar , Tremblay Alain
Published: June 2023

Pleural diseases include a spectrum of disorders broadly categorized into pneumothorax and pleural effusion. They often cause pain, breathlessness, cough, and reduced quality of life. The global burden of diseases reflects regional differences in conditions and exposures associated with pleural disease, such as smoking, pneumonia, tuberculosis, asbestos, cancer, and organ failure. Disease burden in high-income countries is overrepresented given the availability of data and disease burden in lower-income countries is likely underestimated. In the United States, in 2016, there were 42,215 treat-and-discharge visits to the emergency room for pleural diseases and an additional 361,270 hospitalizations, resulting in a national cost of $10.1 billion.
Adaptive agency: the satire genre and the motives behind its use in the era of social media in China
Authors: Xi Yipeng
Published: June 2023

Unlike previous studies analyzing the effect of being exposed to satire, this study adopts a meta-discursive approach to explore the generic features of Chinese satire and the underlying motives and reference frames behind satire use. Drawing on the satire scripts collected from 33 stand-up comedians, I integrated computer-aided topic modeling, discursive historical analysis, and semi-structured interviews to examine how the satirical target is constructed as well as the rationales behind the uses of satire. My findings suggest that most of the Chinese satire analyzed is related to micropolitics in personal social circles, such as gender norms, parent-child relationships, and employment conflicts. These satirical thoughts originate from the satirist’s aversion to inconsistency between words and actions, the release of past trauma, and the performative presentation of morality. I further argue that these reference frames consistently manifest an adaptive agency that satirists simultaneously adapt to the rules while also reestablishing norms in an unconventional way.
Ultra-high-speed camera with laser-induced fluorescence characterizes hypersonic nitric oxide
Authors: Liebendorfer Adam
Published: June 2023

Experimental approach validates industry-standard simulations for tracking thermochemical byproducts at speeds faster than Mach 5.
Allosteric communication between ACE2 active site and binding interface with SARS-CoV-2
Authors: Mugnai Mauro L. , Thirumalai D.
Published: June 2023

SARS-CoV-2, the virus causing COVID-19, initiates cell invasion by deploying a receptor binding domain (RBD) to recognize the host transmembrane peptidase angiotensin-converting enzyme 2 (ACE2). Numerous experimental and theoretical studies have adopted high-throughput and structure-guided approaches to (i) understand how the RBD recognizes ACE2, (ii) rationalize, and (iii) predict the effect of viral mutations on the binding affinity. Here, we investigate the allosteric signal triggered by the dissociation of the ACE2-RBD complex. To this end, we construct an Elastic Network Model (ENM), and we use the Structural Perturbation Method (SPM). Our key result is that complex dissociation opens the ACE2 substrate-binding cleft located away from the interface and that fluctuations of the ACE2 binding cleft are facilitated by RBD binding. These and other observations provide a structural and dynamical basis for the influence of SARS-CoV-2 on ACE2 enzymatic activity. In addition, we identify a conserved glycine (G502 in SARS-CoV-2) as a key participant in complex disassembly.
Evaluation of a new calibration method for bilirubinometers measurements
Authors: Faramawy Samaa M.
Published: June 2023

Although bilirubin meters are still continuously widely used to screen neonatal jaundice worldwide, they still need a metrological calibration method to evaluate the measurement accuracy of these kinds of devices. In this article, the author describes a new calibration method for evaluation of the bilirubinometers measurements and evaluates the results with one of the most common statistical metrological techniques to establish and evaluate the calibration method; the techniques are x̄ and R control charts. The method mainly depends on establishing a correlation between two units, the bilirubin unit (mg/dl) and one of the metrological standard SI units, the irradiance (W/cm2), experimentally to achieve the calibration method. The study results showed that the estimated correlation coefficient of irradiance response to the bilirubinometer under test was around 0.80, which is a primary indication that the method is a considerably valid technique. In addition, the calibration method was evaluated by the statistical parameters x̄ and R control charts, and the results concluded that the variability calibration process is stable, controlled, and hence could be promisingly utilized to evaluate various bilirubinometers with satisfied accuracy and precision in measurements.
Cylindrical first-order superintegrability with complex magnetic fields
Authors: Kubů Ondřej , Šnobl Libor
Published: June 2023

This article is a contribution to the study of superintegrable Hamiltonian systems with magnetic fields on the three-dimensional Euclidean space E3 in quantum mechanics. In contrast to the growing interest in complex electromagnetic fields in the mathematical community following the experimental confirmation of its physical relevance [Peng et al., Phys. Rev. Lett. 114, 010601 (2015)], they were so far not addressed in the growing literature on superintegrability. Here, we venture into this field by searching for additional first-order integrals of motion to the integrable systems of cylindrical type. We find that already known systems can be extended into this realm by admitting complex coupling constants. In addition to them, we find one new system whose integrals of motion also feature complex constants. All these systems are multiseparable. Rigorous mathematical analysis of these systems is challenging due to the non-Hermitian setting and lost gauge invariance. We proceed formally and pose the resolution of these problems as an open challenge.
Explicit nondegeneracy conditions of KAM tori for the planar N-point vortex systems
Authors: Xiong Xuanqing , Liu Qihuai
Published: June 2023

In this paper, we give an explicit nondegeneracy condition for the existence of Kolmogorov-Arnold-Moser (KAM) tori of an N-point vortex system on the plane by using the method of reduction via generalized Jacobi coordinates and matrix theory. Furthermore, by constructing a series of canonical transformations to reduce the degree of freedom of the Hamiltonian, we obtain a new simplified Hamiltonian system. Finally, we give the equivalent relationship between the relative equilibrium point of the original system and the equilibrium point of the new system.
Clean three-level direct-phonon injection terahertz quantum cascade laser
Authors: Wang Li , Lin Tsung-Tse , Wang Ke , Hirayama Hideki
Published: June 2023

For terahertz quantum cascade lasers employing the nonalignment injection scheme via direct-phonon resonance, this study presents the crucial effect of parasitic absorption in the narrow module architecture based on only two quantum wells. The optical gain can be restricted to small (or negative) values even at the low temperature. To address this issue, a suppression strategy by increasing the injection energy is used to isolate the relevant levels. The feasibility of this strategy is experimentally demonstrated by observing lasing at 194 K.
Measurement of the bonding energy via non-planar direct bonding
Authors: Birckigt Pascal , Rothhardt Carolin , Harnisch Gerd , Risse Stefan , Zeitner Uwe D.
Published: June 2023

An accurate measurement of the bonding energy of an interface is important in many areas of applied research. We present a novel method for measuring the bonding energy, which is based on the principle of non-planar direct bonding, i.e., direct bonding of originally planar wafers onto non-planar substrates. We discuss in detail the advantages and disadvantages compared to the commonly used double cantilever beam method. To demonstrate the practical relevance, by using the example of glass wafers, the evolution of the bonding energy during different de-bonding steps is investigated, focusing on how the surface shape variations and the surface roughness affects water stress corrosion. We find that the bonding energy in the corroded state is not affected by the original surface shape variations and mid-spatial frequency range roughness, anymore. A molecular mechanism to explain this phenomenon is proposed.
Impact of edge biasing on the cross-field transport and power spectra
Authors: Shankar Vijay , Bisai N. , Raj Shrish , Sen A.
Published: June 2023

The impact of positive and negative edge biasing on the interchange plasma turbulence in the edge and scrape-off layer (SOL) regions of a tokamak is assessed by comparing numerical simulation results with and without any biasing. The concomitant modifications in the radial transport and power spectra are also analyzed. It is found that a positive bias shifts the peak of the ky-spectra toward a lower ky value in the edge region, but no such shift takes place in the SOL region. A negative bias produces a negligible shift. The heat and particle fluxes in the edge region are seen to increase with the radial electric field shear in the region where a flow reversal takes place. Elsewhere, the fluxes decrease with an increase in the shear. The heat and particle loads per unit time on the limiter/divertor material plates decrease with the biasing voltages in comparison to those w/o biasing, but the load intensities increase. It is found that the blob fraction decreases with the radial electric field shear, but at lower radial positions around the biasing region, it increases from −16 to +64 V.
Argon, neon, and nitrogen impurity transport in the edge and SOL regions of a tokamak
Authors: Raj Shrish , Bisai N. , Shankar Vijay , Sen A.
Published: June 2023

Numerical simulations of the interchange plasma turbulence in the presence of medium-Z impurities (N2, Ne, and Ar) seeding have been performed using BOUT++. These simulation results are used to study the impurity transport mechanism in the edge and scrape-off layer (SOL) regions. An analytical relation for the impurity ion density with the vorticity, sources and sinks, and mass to charge ratio has also been derived. Simulation shows that Ar+ moves more strongly inward compared to N+ and Ne+ that has been verified from the analytical relation. The most abundant species move in both the inward and outward directions, but on average, they mainly move outward. These behaviors have been confirmed using cross-correlation techniques. The inward transport or negative flux of the impurity ions is found directly associated with the monopolar density holes in the presence of the electron temperature gradient, whereas the outward transport is associated with the plasma blobs. The inward impurity transport has been analyzed using hole fraction analysis. The percentages of Ar+, Ne+, and N+ ions of their total impurity densities transported inward mainly through the avalanche events of the turbulent plasma are presented.
Influences of processing temperatures on the nature of polarization phenomena in 85% (Bi0.5Na0.5)TiO3-15%BaTiO3 with different strategies of bismuth oxide non-stoichiometry
Authors: Fan Zhongming , Randall Clive A.
Published: June 2023

Adding excessive metal oxide doping to a powder batch is a known way to compensate for the loss of volatile cation species during high temperature sintering. An important case in the piezoelectric ceramics is the bismuth oxide in the lead-free ferroelectric ceramic bismuth sodium titanate (BNT). Building from the earlier knowledge about excessive bismuth oxide's influences on the properties of BNT, we further note that varying the sintering temperature can both control the distribution of excessive Bi3+ and impact the relaxor/normal ferroelectric behaviors and corresponding phase transition. In addition to the nature of polarization, the sintering temperature also significantly manipulates the electrical conductivity. A hypothetical mechanism for the resistive grain boundary is proposed, based on inferences from electrical—microstructure—processing relations in 85% Bi0.5Na0.5TiO3-15% BaTiO3 with batched Bi2O3 excess and acceptor Mg2+ in a co-doped strategy.
Microsphere-assisted enhanced photothermal lens detection integrated with digital holographic microscopy for 3D particle sensing and thermal diffusivity measurement
Authors: Kabi S. , Moradi A. R. , Cabrera H.
Published: June 2023

In this paper, we show that by extending the concept of “microsphere-assisted imaging” into thermal lens (TL) detection, enhancement of photothermal detection is achieved. Furthermore, by integration of TL detection and digital holographic microscopy (DHM), we provide simultaneous measurement of photothermal properties as well as complementary imaging of the sample. Simultaneous acquisition of photothermal properties and imaging is essential for characterization of a variety of samples in biochemistry, material science, and process technologies. TL is a sensitive methodology to detect low concentrations of analytes in low-loss samples, and DHM in the transmission mode is an effective technique for label-free, non-contact, and real-time imaging and measurement of phase objects, such as biomaterials. We demonstrate the usefulness of the TL-DHM integrated system by applying it for acquisition of photothermal maps of samples as well as obtaining their morphometrical information. Additionally, we measure the thermal diffusivity of polydimethylsiloxane because of the focusing effect of polystyrene microspheres. The system has the potential to be applied for a variety of objects including bio-samples and may be proposed as a bench-top characterization device.
TimeSOAP: Tracking high-dimensional fluctuations in complex molecular systems via time variations of SOAP spectra
Authors: Caruso Cristina , Cardellini Annalisa , Crippa Martina , Rapetti Daniele , Pavan Giovanni M.
Published: June 2023

Many molecular systems and physical phenomena are controlled by local fluctuations and microscopic dynamical rearrangements of the constitutive interacting units that are often difficult to detect. This is the case, for example, of phase transitions, phase equilibria, nucleation events, and defect propagation, to mention a few. A detailed comprehension of local atomic environments and of their dynamic rearrangements is essential to understand such phenomena and also to draw structure–property relationships useful to unveil how to control complex molecular systems. Considerable progress in the development of advanced structural descriptors [e.g., Smooth Overlap of Atomic Position (SOAP), etc.] has certainly enhanced the representation of atomic-scale simulations data. However, despite such efforts, local dynamic environment rearrangements still remain difficult to elucidate. Here, exploiting the structurally rich description of atomic environments of SOAP and building on the concept of time-dependent local variations, we developed a SOAP-based descriptor, TimeSOAP (τSOAP), which essentially tracks time variations in local SOAP environments surrounding each molecule (i.e., each SOAP center) along ensemble trajectories. We demonstrate how analysis of the time-series τSOAP data and of their time derivatives allows us to detect dynamic domains and track instantaneous changes of local atomic arrangements (i.e., local fluctuations) in a variety of molecular systems. The approach is simple and general, and we expect that it will help shed light on a variety of complex dynamical phenomena.
Convolutional neural network-based pose mapping estimation as an alternative to traditional hand–eye calibration
Authors: Zhou Kuai , Huang Xiang , Li Shuanggao , Li Gen
Published: June 2023

The vision system is a crucial technology for realizing the automation and intelligence of industrial robots, and the accuracy of hand–eye calibration is crucial in determining the relationship between the camera and robot end. Parallel robots are widely used in automated assembly due to their high positioning accuracy and large carrying capacity, but traditional hand–eye calibration methods may not be applicable due to their limited motion range and resulting accuracy problems. To address this issue, we propose using a pose, nonlinear mapping estimation method to solve the hand–eye calibration problem and have constructed a 1-D pose estimation convolutional neural network (PECNN) with excellent performance, through experiments and discussions. The PECNN achieves an end-to-end mapping of the variation of the target object pose to the variation of the robot end pose. Our experiments have shown that the proposed hand–eye calibration method has high accuracy and can be applied to the automated assembly tasks of vision-guided parallel robots. Moreover, the method is also applicable to most parallel robots and tandem robots.
Experimental investigation on “glow flow” phenomenon during current-zero period between transverse magnetic contacts
Authors: Jiang Yuzi , Xiu Shixin , Wei Leming , Liu Shiqi , Yang Yu , Guo Meiqin
Published: June 2023

The inter-electrode state of the transverse magnetic field contact during the current-zero period is determined by the evolution of the arcing process. It has an important effect on whether the vacuum switch can be successfully broken. In this paper, a series of contacts were subjected to arcing and fixed gap distance experiments. The results show that a special inter-electrode phenomenon (glow flow) appears during the current-zero period when the current exceeds the threshold for the transition from diffused to constricted state of the vacuum arc. The mechanism behind the formation of this phenomenon was elucidated through an analysis of multiple sets of experimental results. It is found that the inter-electrode phenomenon arises from the disruption of the equilibrium process between the pressure from the arc column plasma and the anode vapor flux on the near-anode side at the current-zero. The copper vapor falls and is ionized by collisions with heat-emitting electrons. The experimental results and theoretical analysis also show that this phenomenon has a time interval with the reignition phenomenon. When this phenomenon is intense to a certain degree, the reignition will occur with high probability. The observation and theoretical analysis results of this paper are relatively consistent with the research results of other scholars, which can help to improve the vacuum arc characteristics and interrupting mechanism. This can provide a basis for improving the arc extinction performance of the vacuum switch.
Dual hydrodynamic trap based on coupled stagnation point flows
Authors: Boyd Jarrett , Hepner Gram , Ujhazy Maxwell , Bliss Shawn , Tanyeri Melikhan
Published: June 2023

Recent advancements in science and engineering have allowed for trapping and manipulation of individual particles and macromolecules within an aqueous medium using a flow-based confinement method. In this work, we demonstrate the feasibility of trapping and manipulating two particles using coupled planar extensional flows. Using Brownian dynamics simulations and a proportional feedback control algorithm, we show that two micro/nanoscale particles can be simultaneously confined and manipulated at the stagnation points of a pair of interconnected planar extensional flows. We specifically studied the effect of strain rate, particle size, and feedback control parameters on particle confinement. We also demonstrate precise control of the interparticle distance by manipulating the strain rates at both junctions and particle position at one of the junctions. We further discuss the advantages and limitations of the dual hydrodynamic trap in comparison to existing colloidal particle confinement methods and outline some potential applications in polymer science and biology. Our results demonstrate the versatility of flow-based confinement and further our understanding of feedback-controlled particle manipulation.
Transfer-learned potential energy surfaces: Toward microsecond-scale molecular dynamics simulations in the gas phase at CCSD(T) quality
Authors: Käser Silvan , Meuwly Markus
Published: June 2023

The rise of machine learning has greatly influenced the field of computational chemistry and atomistic molecular dynamics simulations in particular. One of its most exciting prospects is the development of accurate, full-dimensional potential energy surfaces (PESs) for molecules and clusters, which, however, often require thousands to tens of thousands of ab initio data points restricting the community to medium sized molecules and/or lower levels of theory (e.g., density functional theory). Transfer learning, which improves a global PES from a lower to a higher level of theory, offers a data efficient alternative requiring only a fraction of the high-level data (on the order of 100 are found to be sufficient for malonaldehyde). This work demonstrates that even with Hartree–Fock theory and a double-zeta basis set as the lower level model, transfer learning yields coupled-cluster single double triple [CCSD(T)]-level quality for H-transfer barrier energies, harmonic frequencies, and H-transfer tunneling splittings. Most importantly, finite-temperature molecular dynamics simulations on the sub-μs time scale in the gas phase are possible and the infrared spectra determined from the transfer-learned PESs are in good agreement with the experiment. It is concluded that routine, long-time atomistic simulations on PESs fulfilling CCSD(T)-standards become possible.
Field-programmable-gate-array-based digital frequency stabilization of low-phase-noise diode lasers
Authors: Avalos Victor , Nie Xiaoyu , Yang Anbang , He Canming , Kumar Sunil , Dieckmann Kai
Published: June 2023

We present the comparison of a field-programmable-gate-array (FPGA) based digital servo module with an analog counterpart for the purpose of laser frequency stabilization to a high-finesse optical cavity. The transfer functions of both the digital and analog modules for proportional–integral–derivative control are measured. For the lasers stabilized to the cavity, we measure the singe-sideband power spectral density of fast phase noise by means of an optical beat with filtered light transmitted through the cavity. The comparison between the digital and analog modules is performed for two low-phase-noise diode lasers at 1120 and 665 nm wavelengths. The performance of the digital servo module compares well to the analog one for the lowest attained levels of 30 mrad for the integrated phase noise and 10−3 for the relative noise power. The laser linewidth is determined to be in the sub-kHz regime, only limited by the high-finesse cavity. Our work exploits the versatility of the FPGA-based servo module (STEMlab) when used with open-source software and hardware modifications. We demonstrated that such modules are suitable candidates for remote-controlled low-phase-noise applications in the fields of laser spectroscopy and atomic, molecular, and optical physics.
Derivation of an improved smoothed particle hydrodynamics model for establishing a three-dimensional numerical wave tank overcoming excessive numerical dissipation
Authors: Colagrossi Andrea
Published: June 2023

This paper presents an improved smoothed particle hydrodynamics (SPH) model through a rigorous mathematical derivation based on the principle of virtual work, aiming at establishing a three-dimensional numerical wave tank overcoming excessive numerical dissipation that has been usually encountered in traditional SPH models in practical applications. In order to demonstrate the accuracy and convergence of the new scheme, the viscous damping of a standing wave is first investigated as a quantitative validation, with particular attention on emphasizing (1) its physical rationality with respect to energy conservation and (2) its ability to alleviate wave over-attenuation even using fewer neighbors compared with the traditional δ-SPH model. Subsequently, several fully three-dimensional engineering problems, with respect to water wave propagation and the interaction with structures, are investigated to demonstrate the effectiveness of the new scheme in alleviating wave over-attenuation. It is demonstrated that the present model can be performed with relatively few neighbors (i.e., higher computational efficiency) to obtain accurate and convergent numerical results for those SPH simulations involving long-term and long-distance water wave propagation.
Polytropic representation of non-isotropic kinetic pressure tensor for non-ideal plasma fluids in relativistic jets
Authors: Cremaschini Claudio
Published: June 2023

Non-ideal fluids are likely to be affected by the occurrence of pressure anisotropy effects, whose understanding for relativistic systems requires knowledge of the energy–momentum tensor. In this paper, the case of magnetized jet plasmas at equilibrium is considered, in which both microscopic velocities of constituent particles and the continuum fluid flow are treated as relativistic ones. A theoretical framework based on covariant statistical kinetic approach is implemented, which permits the proper treatment of single-particle and phase-space kinetic constraints and, ultimately, the calculation of the system continuum fluid fields associated with physical observables. A Gaussian-like solution for the kinetic distribution function (KDF) is constructed, in which the physical mechanism responsible for the generation of temperature anisotropy is identified with magnetic moment conservation. A Chapman–Enskog representation of the same KDF is then obtained in terms of expansion around an equilibrium isotropic Juttner distribution. This permits the analytical calculation of the fluid 4-flow and stress–energy tensor and the consequent proof that the corresponding kinetic pressure tensor is non-isotropic. As a notable result, the validity of a polytropic representation for the perturbative non-isotropic pressure contributions is established, whereby directional pressures exhibit specific power-law functional dependences on fluid density.
High electric field characteristics of GaAsSb photodiodes on InP substrates
Authors: Jung H. , Lee S. , Liu Y. , Jin X. , David J. P. R. , Krishna S.
Published: June 2023

Low noise avalanche photodiodes (APDs) detecting 1550 nm wavelength play a crucial role in optical communication and LiDAR systems. These APDs utilize a separate absorption, charge, and multiplication (SACM) architecture with an absorber for 1400–1650 nm detection and a low noise, high gain multiplier that can be independently optimized for a high signal-to-noise ratio. Recently, GaAs0.5Sb0.5/Al0.85Ga0.15As0.56Sb0.44 SACM APDs have demonstrated ultra-high gain and extremely low noise, possibly improving sensitivity over Si and InGaAs/InP commercial APDs. This accomplishment was achieved using a GaAsSb absorber instead of a conventional InGaAs absorber, mitigating band discontinuities between the absorber and the multiplier. However, further optimization is required to reduce noise due to tunneling and impact ionization from the GaAsSb absorber, which occurs at a high electric field region. This paper focuses on the study of the high-field characteristics of GaAsSb photodiodes (PDs). The tunneling phenomenon is analyzed through current density-voltage measurements, and the impact ionization behavior is evaluated by measuring the multiplication of p-i-n GaAsSb PDs. The result suggests that when designing a SACM APD with a GaAsSb absorber, the electric field in the absorber can be increased to 175 kV/cm without the detrimental effects of ionization occurring in the absorber. The findings from this investigation will assist in optimizing GaAsSb-based SACM APDs and promoting further advancements in the 1550 nm APD technology.
Stabilization of low-threshold two-plasmon parametric decay instability at oblique incidence of a microwave pump beam onto the plasma
Authors: Gusakov E. Z. , Popov A. Yu.
Published: June 2023

It is shown that with an oblique incidence of a pump microwave in X2-mode electron cyclotron plasma heating (ECRH) experiments, the threshold power of a parametric decay instability (PDI) leading to excitation of two trapped upper hybrid waves increases and the anomalous absorption level decreases. It is proposed to use a small pump beam tilt along the magnetic field to suppress this most dangerous PDI, often observed in the X2-mode ECRH experiments.