bluuebunny/crossref_metadata_2025 huggingface dataset:
Physics Teacher Professional Learning
Authors: McLoughlin Eilish , Sokolowska Dagmara
Published: March 2023

This chapter presents an overview of the current situation of physics teacher professional learning, encompassing pre-service teachers at the start of their teaching careers and throughout the lifetime of their teaching careers. We outline the needs and opportunities for teacher professional learning in several educational systems, including the transnational mobility program offered to teachers in Europe. We reflect on the frameworks for teacher professional learning that support teachers to develop their general pedagogical content knowledge and specialized content knowledge for teaching physics. We explore the strategies for reflective, collaborative interaction between teachers and researchers, focused on reinforcing teacher's confidence in teaching physics and developing their competencies for long-life learning. Overall, this chapter explores the state-of-the-art of teacher professional development and how these strategies can be utilized to support physics teachers in designing teaching and learning activities that address the needs of future physics learners.
Research on the Development of Faculty, Graduate Teaching Assistants, and Undergraduate Learning Assistants
Authors: Otero Valerie K. , Alicea-Muñoz Emily
Published: March 2023

This chapter explores the literature that investigates how physics instructors are supported when building learning environments that capitalize on research-based instructional strategies. The research demonstrates the value of real-time, context-specific, faculty development models that explicitly build on their knowledge and experience. Similarly, the research on Graduate Teaching Assistants highlights the value of their training being situated in teaching practice and the value of Graduate Teaching Assistants feeling like a part of the instructional team, in partnership with faculty members who lead a course. The Learning Assistant model is presented in this chapter as a real-time, context-specific solution to faculty development, where Learning Assistants, Graduate Teaching Assistants, and faculty members serve on an instructional team that is supported by LA program staff in their mission to improve their instruction and increase student voice in the classroom.
Mechanomemory in protein diffusivity of chromatin and nucleoplasm after force cessation
Authors: Rashid Fazlur , Liu Wenjie , Wang Qianchun , Ji Baohua , Irudayaraj Joseph , Wang Ning
Published: March 2023

It is known that external mechanical forces can regulate structures and functions of living cells and tissues in physiology and diseases. However, after cessation of the force, how structures are altered in response to the dynamics of the chromatin and molecules in the nucleoplasm remains elusive. Here, using single-molecule imaging approaches, we show that exogenous local forces via integrins applied for 2 to 10 min decondensed the chromatin and increased chromatin and nucleoplasm protein mobility inside the nucleus, leading to elevated diffusivity of single protein molecules in the nucleoplasm, tens of minutes after the cessation of force. Diffusion experiments with fluorescence correlation spectroscopy in live single cells show that the mechanomemory in chromatin and nucleoplasm protein diffusivity was regulated by nuclear pore complexes. Protein molecular dynamics simulation recapitulated the experimental findings in live cells and showed that nucleoplasm protein diffusivity was regulated by the number of nuclear pore complexes. The mechanomemory in elevated protein diffusivity of the nucleoplasm after force cessation represents a physical process that reverses protein–protein condensation in phase separation via unjamming of the chromatin. Our findings of mechanomemory in chromatin and nucleoplasm protein diffusivity suggest that the effect of force on the nucleus remains tens of minutes after force cessation and thus is more far-reaching than previously anticipated.
Dissection of complement and Fc-receptor-mediated pathomechanisms of autoantibodies to myelin oligodendrocyte glycoprotein
Authors: Mader Simone , Ho Samantha , Wong Hoi Kiu , Baier Selia , Winklmeier Stephan , Riemer Carolina , Rübsamen Heike , Fernandez Iris Marti , Gerhards Ramona , Du Cuilian , Chuquisana Omar , Lünemann Jan D. , Lux Anja , Nimmerjahn Falk , Bradl Monika , Kawakami Naoto , Meinl Edgar
Published: March 2023

Autoantibodies against myelin oligodendrocyte glycoprotein (MOG) have recently been established to define a new disease entity, MOG-antibody-associated disease (MOGAD), which is clinically overlapping with multiple sclerosis. MOG-specific antibodies (Abs) from patients are pathogenic, but the precise effector mechanisms are currently still unknown and no therapy is approved for MOGAD. Here, we determined the contributions of complement and Fc-receptor (FcR)-mediated effects in the pathogenicity of MOG-Abs. Starting from a recombinant anti-MOG (mAb) with human IgG1 Fc, we established MOG-specific mutant mAbs with differential FcR and C1q binding. We then applied selected mutants of this MOG-mAb in two animal models of experimental autoimmune encephalomyelitis. First, we found MOG-mAb-induced demyelination was mediated by both complement and FcRs about equally. Second, we found that MOG-Abs enhanced activation of cognate MOG-specific T cells in the central nervous system (CNS), which was dependent on FcR-, but not C1q-binding. The identification of complement-dependent and -independent pathomechanisms of MOG-Abs has implications for therapeutic strategies in MOGAD.
Teachers gaining awareness of L2 pragmatics by means of an asynchronous professional development module
Authors: Cohen Andrew D. , Knight Stephanie W.P. , Sykes Julie M.
Published: March 2023

While teacher education is a crucial element to ensuring that second language (L2) pragmatics gains traction in classrooms and curricula, it would appear that teacher development programs provide only modest focus in this area. This chapter reports on findings from a preliminary case study in which three Spanish teachers accessed an asynchronous teacher education online module aimed at heightening their awareness of L2 pragmatics and the important role that it can play in language instruction. The results indicate that asynchronous professional development (PD) materials provide teachers with resources which they can access conveniently for the purpose of gaining insights into lesson sequencing, identification of key content and development of strategies for teaching L2 pragmatics in the classroom.
Teachers’ awareness, knowledge and attitudes towards instruction in L2 pragmatics
Authors: Glaser Karen
Published: March 2023

Despite its crucial contribution to second/foreign language (L2) competence, pragmatics has still not gained a fixed place in many language teacher training programs. To address this, a workshop for in-service primary English as a Foreign Language (EFL) teachers was conducted to raise awareness of L2 pragmatics and to present suggestions for teaching it in the classroom. This chapter documents the contents of this professional training course and presents insights into the participants’ expectations and perceptions of the workshop, as well as their knowledge and attitudes towards the teaching of L2 pragmatics. Data was collected by means of questionnaires at the beginning and end of the workshop. In addition to presenting the results, the chapter discusses implications for teacher education to help bring pragmatics into the L2 classroom on a wider scale.
Skill acquisition based approach to teaching L2 pragmatics
Authors: Nguyen Thi Thuy Minh , Pham Thi Thanh Thuy
Published: March 2023

Skill Acquisition Theory describes second language (L2) learning as a gradual transition from effortful use to more automatic use of L2 knowledge, as a result of deliberate and systematic practice. In this chapter, we address the skill-acquisition based approach to teaching L2 pragmatics by first presenting the theory and its constructs of declarative knowledge, proceduralisation and automatisation and reviewing existing instructional L2 pragmatics research that lends support to the theory. We then illustrate how the theory can be applied to design L2 pragmatic instruction by reporting an empirical study into the role of feedback and revision in teaching emails of complaints. Based on the discussion of the findings, we end by drawing implications for pragmatics pedagogy and recommend topics for further research.
Vector-tensor gravity from a broken gauge symmetry
Authors: Chagoya Javier , Sabido Miguel , Silva-García A
Published: March 2023

In this paper we present a Yang-Mills type gauge theory of vector-tensor gravity, where the tetrad, the spin connection and vector field are identified with components of the gauge field. This setup leads to a theory that in flat spacetime is contained in Generalized Proca theories, while in curved spacetime is closely related to beyond Generalized Proca. We solve for static and spherically symmetric space-time and show that there are two branches of solutions, one where the metric is asymptotically Schwarzschild even though there is a cosmological constant in the action, and another one where the metric is asymptotically (anti-)de Sitter. Also, we study the effect of the vector field on homogeneous and isotropic spacetimes, finding that it contributes to the accelerated expansion of the spacetime.
Enhanced energy storage performance in polypropylene-acrylic acid grafted polypropylene-ZrO2 ternary nanocomposites
Authors: Liu Wenfeng , Liu Hongbo , Cheng Lu , Li Shengtao
Published: March 2023

To improve the energy storage density while maintaining low dielectric loss is crucial for the miniaturization of capacitors. In the present study, we proposed a ternary nanocomposite system comprised of polypropylene (PP), acrylic acid grafted PP (PP-g-AA), and nano-ZrO2. The PP-g-AA was firstly prepared by a free radical grafting with the proportion fixed to 50 wt%, and the content of nano-ZrO2 ranged from 0.5 wt% to 5 wt% to tailor the ternary composite. The transmission electron microscope observation showed that PP-g-AA could significantly benefit the dispersion of nanoparticles and the differential scanning calorimetry results indicated the superior compatibility of the ternary nanocomposites. Accordingly, with the optimum nano-ZrO2 content of 0.5 wt%, the ternary nanocomposites achieved the permittivity of 2.7 and DC breakdown strength of 456.2 kV mm−1, resulting in the enhanced energy density of 2.77 J cm−3 which was 60% higher than neat PP, while the dielectric loss was kept lower than 0.003. Moreover, even at the temperature of 120 °C, the ternary nanocomposites maintained a high-performance energy storage density of 2.28 J cm−3 (with energy storage efficiency above 90%), which was 670% of the neat PP.
Dynamic reactions of defects in ion-implanted 4H-SiC upon high temperature annealing
Authors: Liu Xinghua , Ren Fang-Fang , Wang Zhengpeng , Sun Xinyu , Yang Qunsi , Wang Yiwang , Ye Jiandong , Chen Xiufang , Xu Wei-Zong , Zhou Dong , Xu Xiangang , Zhang Rong , Lu Hai
Published: March 2023

Single-photon emitters based on intrinsic defects in silicon carbide (SiC) are promising as solid-state qubits for the quantum information storage, whereas defect engineering in a controllable manner still remains challenging. Herein, the thermally-driven defect dynamic reaction in the ion implanted 4H-SiC has been exploited through the optical emission spectra of defects. For the heavy-ion (Si or Ar) implanted samples with abundant Frenkel pairs, the silicon vacancies (VSi) are energetically converted into the carbon antisite-vacancy pair (CSi-VC) upon annealing till 1300 °C for 30 min, accompanied with the gradual lattice recovery and local strain relaxation. The further temperature elevation dissociates the metastable CSi-VC into carbon antisite (CSi) and carbon vacancy (VC), as supported by the consequent quenching of the (CSi-VC)-related emission at 700 nm. Thus, the whole defect reaction is probed as the vacancy interconversion from VSi to VC with the byproduct of stacking faults. In contrast, the intermediate CSi-VC complexes are not energetically favorable during the annealing of the H-implanted sample, which results from the negligible generation of Frenkel pairs, as supported by the x-ray diffraction patterns and Raman scattering analysis. These findings provide guidance for defect engineering in SiC toward the creation of reliable single photon emitters.
The cumulant Green’s functions method for the Hubbard model
Authors: Lira R N , Riseborough P S , Silva-Valencia J , Figueira M S
Published: March 2023

We use the cumulant Green’s functions method (CGFM) to study the single-band Hubbard model. The starting point of the method is to diagonalize a cluster (‘seed’) containing N correlated sites and employ the cumulants calculated from the cluster solution to obtain the full Green’s functions for the lattice. All calculations are done directly; no variational or self-consistent process is needed. We benchmark the one-dimensional results for the gap, the double occupancy, and the ground-state energy as functions of the electronic correlation at half-filling and the occupation numbers as functions of the chemical potential obtained from the CGFM against the corresponding results of the thermodynamic Bethe ansatz and the quantum transfer matrix methods. The particle-hole symmetry of the density of states is fulfilled, and the gap, occupation numbers, and ground-state energy tend systematically to the known results as the cluster size increases. We include a straightforward application of the CGFM to simulate the singles occupation of an optical lattice experiment with lithium-6 atoms in an eight-site Fermi-Hubbard chain near half-filling. The method can be applied to any parameter space for one, two, or three-dimensional Hubbard Hamiltonians and extended to other strongly correlated models, like the Anderson Hamiltonian, the t − J, Kondo, and Coqblin-Schrieffer models.
A review on the size-dependent bulking, vibration and, wave propagation of nanostructures
Authors: Wang Jing , Yu Yanglan , Zhao Xiang , Sun Jianqiang , Wang Yuxing , Zhu Hongjun
Published: March 2023

Size effect is a typical characteristic of micro-/nano-materials, which can contribute to a variety of size-dependent behaviors, phenomena, and properties, such as stiffness softening, deformation springback, etc. The intrinsic causes of size effects are micro-structural properties of materials, and the sensitivity of microstructural properties of materials is closely related to the smallest structural unit of the crystal, crystal defects and geometric dimensions, and is heavily influenced by the material’s field conditions. The modeling method based on non-local theory and gradient theory in the model is not only consistent with experimental and molecular dynamics simulation results, but also provides a solid explanation for the size effect underlying ‘softening’ and ‘hardening’ behaviors. Taking this as a basic point, this paper further considers the real working environment of materials, and systematically reviews the static and dynamic mechanical behavior cases of various nano-structures, mainly involving bulking, vibration and wave propagation of micro-beams and plates under different theories. A description and discussion of the differences in mechanical properties resulting from size effects under various theoretical frameworks and three key bottleneck problems are provided: the selection of kernel functions, the determination of size parameters, and the physical meaning of boundary conditions at higher orders. A summary is provided of the possible avenues and potentials for size effect models in future research. Many studies have shown that size parameters have a significant impact on the mechanical behavior of micro-/nano-structures, and these effects will increase as the size of the structure decreases. Nevertheless, different theories have varying scopes of application and size effects, and further research is needed to develop a unified size-dependent theory with universal applicability. A major focus of this paper is on the size effect of micro-/nano-structures, as well as provides the necessary data support to resolve the bottleneck problem associated with the size effect in the processing and manufacturing industries, and realizes the design and optimization of micro-scale parts based on their size.
Thermographic 3D particle tracking velocimetry for turbulent gas flows
Authors: Stelter Moritz , Martins Fabio J W A , Beyrau Frank , Fond Benoît
Published: March 2023

Turbulent flows are characterized by diverse and unsteady three-dimensional (3D) features that require 3D measurements to study. In case of non-isothermal flows, combined 3D measurements of temperature and velocity are necessary. In this paper, a thermographic 3D particle tracking velocimetry (thermographic 3D-PTV) concept is introduced for simultaneous 3D temperature and velocity measurements in turbulent gas flows. It is based on sub-micron thermographic phosphor particles seeded into the flow as flow tracers with low response times of a few microseconds. To obtain each tracer’s position and velocity, the measurement region is illuminated volumetrically using a double-pulse green laser and Mie-scattered light is imaged by four double-frame cameras. Following the pinhole model-based calibration of all cameras, 3D particle positions are computed for both laser pulse-times using a fast minimum line of sight reconstruction code. Three-component velocities are derived from tracking individual particles between these time steps. For simultaneous 3D thermometry, temperature dependent luminescence emissions from the same phosphor particles are exploited. These emissions are excited using a UV laser synchronized with the first green laser pulse and imaged using two cameras equipped with spectral filters for ratiometric phosphor thermometry. As a result, instantaneous 3D fields of discrete temperature and velocity measurements are obtained throughout the volume. The concept is demonstrated in a turbulent heated gas jet emerging from a circular nozzle at a particle image concentration of 0.005 particle per pixel, where the symmetry of the velocity and temperature distributions about the jet axis is successfully reconstructed.
Sound field separation technique for nonplanar sources based on field prediction by using statistically optimized near-field acoustic holography
Authors: Cheng Wei , Ou Kai , Song Chao , Chen Shuang , Chen Xuefeng , Gao Lin , Wang Jun , Zhao Yanan , Yang Mingsui
Published: March 2023

For the sound field of cylindrical or compact sources, the current sound field separation technique (FST) based on statistically optimized near-field acoustic holography (SONAH) uses planar wave for separation, and the effects of different wave functions have not yet been studied. However, the non-conformal problem between the hologram surface and the sound sources commonly has a risk of accuracy reduction. Here, an FST for nonplanar sources based on SONAH is proposed to solve this problem. First, considering that field prediction of near-field acoustic holography will attenuate errors, noise immunity of the FST is effectively improved in a noisy environment by moving the reconstruction surface to the prediction area. Subsequently, the appropriate conformal wave function is determined by combining the shape of the sound source and is substituted into the improved method in the first step to separate the free-field sound pressure. Finally, simulations, experiments using loudspeakers, and a cylindrical experiment platform prove the effectiveness of the proposed method, which can greatly improve the adaptability and reliability of the FST in nonplanar sound sources in mechanical systems.
2D Bi2Te3/Si heterostructure with high thermoelectric power factor enabled by interface regulated carrier injection
Authors: Chen Lili , Zhu Beibei , Chen Jiayi , Xing Shanshan , Tao Li
Published: March 2023

It has been highly demanded to optimize the charge carrier concentration in 2D Bi2Te3 to achieve enhanced thermoelectric performance. This work reveals that, constructing 2D Bi2Te3/Si heterostructure with tuned interfacial electronic band structure can meet the above needs. When the work function in Si substrate is decreased from 4.6 to 4.06 eV, the charge carrier concentration and electron effective mass are increased simultaneously. Consequently, the electrical conductivity of 2D Bi2Te3 on n++-Si has reaches up to 1250 S·cm−1, which is 90% higher than the counterpart on SiO2/Si substrate, although the Seebeck coefficient in these two samples is around −103 μV·K−1. The resultant power factor of 2D Bi2Te3/n++-Si heterostructure is 13.4 μW·cm−1·K−2, which is one of the best values among similar studies ever reported. This work demonstrates a facile way to improve thermoelectric properties via interfacial engineering in a heterostructure.
Enhancing optical characteristics of mediator-assisted wafer-scale MoS2 and WS2 on h-BN
Authors: Chiu Sheng-Kuei , Li Ming-Chi , Ci Ji-Wei , Hung Yuan-Chih , Tsai Dung-Sheng , Chen Chien-Han , Lin Li-Hung , Watanabe Kenji , Taniguchi Takashi , Aoki Nobuyuki , Hsieh Ya-Ping , Chuang Chiashain
Published: March 2023

Two-dimensional (2D) materials and their heterostructures exhibit intriguing optoelectronic properties; thus, they are good platforms for exploring fundamental research and further facilitating real device applications. The key is to preserve the high quality and intrinsic properties of 2D materials and their heterojunction interface even in production scale during the transfer and assembly process so as to apply in semiconductor manufacturing field. In this study, we successfully adopted a wet transfer existing method to separate mediator-assisted wafer-scale from SiO2/Si growing wafer for the first time with intermediate annealing to fabricate wafer-scale MoS2/h-BN and WS2/h-BN heterostructures on a SiO2/Si wafer. Interestingly, the high-quality wafer-scale 2D material heterostructure optical properties were enhanced and confirmed by Raman and photoluminescence spectroscopy. Our approach can be applied to other 2D materials and expedite mass production for industrial applications.
Coupling the COST reference plasma jet to a microfluidic device: a new diagnostic tool for plasma-liquid interactions
Authors: Bissonnette-Dulude Julien , Coulombe Sylvain , Gervais Thomas , Reuter Stephan
Published: March 2023

Plasma-liquid interaction processes are central to plasma applications in medicine, environment, and material processing. However, a standardized platform that allows the study of the production and transport of plasma-generated reactive species from the plasma to the liquid is lacking. We hypothesize that use of microfluidic devices would unlock many possibilities to investigate the transport of reactive species in plasma-treated liquids and, ultimately, to measure the effects of these species on biological systems, as microfluidics has already provided multiple solutions in medical treatment investigations. Our approach combines a capacitively coupled RF plasma jet known as the COST reference plasma jet with simple 3D printed microfluidic devices. This novel pairing is achieved by carefully controlling capillary effects within the microfluidic device at the plasma-liquid interaction zone. The generation and transport of reactive species from the plasma to the liquid inside the microfluidic device are analyzed using a colorimetric hydrogen peroxide concentration assay. A capillary flow model is provided to explain the two main regimes of operations observed in the device and their merits are discussed. Overall, the proposed plasma-microfluidic prototype shows great potential for the fundamental study of plasma-liquid interactions and opens the way to the use of standard microfluidic devices with plasma sources developing a plasma column or a plasma plume.
A 3D dislocated re-entrant structure with compression-twist coupling effect
Authors: Chen Xuan , He Tengwu , Hu Yandong , Feng Miaolin
Published: March 2023

Compression-twist metamaterials are artificially designed materials which can realize transformation from axial compressing to twist loading. In this study, a new dislocation design of the 2D re-entrant hexagonal structure is proposed with the compression-shear coupling effect. Through orthogonal assembling, its 3D dislocation re-entrant structure is successfully obtained that exhibits compression-twist coupling effect. A theoretical model is built to clarify the deformation mechanisms of the novel structures, and relevant analyses indicate that the compression-twist coupling effects can be tuned by tailoring structure’s geometric parameters with a wide range of adjustable twist angles. Besides, the experiments and numerical simulations are also performed to verify our developed theoretical model, and finally more feasible structure designs are extended with compression-twist coupling effect based on the re-entrant structure. The novel 3D material structure with excellent compression-twist coupling effects provides new ideas for the design of compression-twist metamaterials.
Development of superconducting model dipole magnets beyond 12 T with a combined common-coil configuration
Authors: Wang Chengtao , Wang Yingzhe , Shi Jinrui , Feng Ze , Li Chunyan , Wang Juan , Kang Rui , Li Wei , Feng Ao , Yang Huan , Liu Zhongxiu , Zhou Jin , Chen Xin , Xu Qingjin
Published: March 2023

The superconducting magnet group at IHEP (the Institute of High Energy Physics, Chinese Academy of Sciences, China) has been engaging in the R&D of high field accelerator magnets since 2014 for the pre-study of the next-generation high energy particle accelerators like CEPC-SPPC (Circular Electron Positron Collider-Super Proton Proton Collider), FCC (Future Circular Collider), etc. A superconducting model dipole magnet named LPF1 was first fabricated with NbTi and Nb3Sn in a combined common-coil configuration in 2017 and tested in 2018, a main field of 10.23 T was reached within two 10 mm apertures. The magnet was reassembled with higher pre-stress in 2019 to investigate the influence of the pre-stress loading level on the performance of common-coil dipole magnets. The main field of this upgraded magnet named LPF1-S was increased to 10.71 T within two 12 mm apertures. By improving the key processing technologies in Rutherford cable fabrication, coil winding, Nb3Sn & NbTi splices soldering and coil impregnation, the recently fabricated model dipole magnet named LPF1-U attained a 12.47 T main field in two 14 mm apertures in 2021. To fully take advantage of Nb3Sn and NbTi superconductors in different field regions, LPF1-U was still designed and developed with a combined coil configuration with Nb3Sn for the inner two coils and NbTi for the outer four coils. Additionally, graded coil topology and different coil LSS (length of straight section) settings were adopted in the optimization of LPF1-U layouts. Bladder and key technology was used for the support structure, and fiber optic sensors based on FBG (fiber Bragg grating) were utilized to monitor the stress distribution and variation in the structures and coils through the whole process from magnet assembly to cool-down and excitation. During the performance test, a relatively large number of trainings were carried out and LPF1-U became more stable after the thermal cycle. A peak field of 12.7 T in the coils (12.47 T main field in apertures) corresponds to an operating current of 6865 A and a load line ratio of 90% was finally attained. It is worth mentioning that LPF1-U is the first hybrid—Nb3Sn, NbTi—common coil dipole magnet that has achieved a main field of more than 12 T in two apertures. The design, fabrication and performance analysis of the LPF series dipole magnets are presented in this paper.
One-way acoustic beam splitting in spatial four-waveguide couplers designed by adiabatic passage
Authors: Tang Shuai , Wu Jin-Lei , Lü Cheng , Yao Jiabao , Wang Xiaosai , Song Jie , Jiang Yongyuan
Published: March 2023

In this work, we introduce quantum-mechanical adiabatic passage into the design of spatial acoustic four-waveguide (WG) couplers. Thanks to the agreement in form between the Schrödinger equation in quantum mechanics and the coupled-mode equation of classical wave, the behavior of propagating wave in coupled WGs is capable of mapping to quantum states driven by external fields. By coupling the input and output WGs with a mediator WG in space, an apparent beam splitting is realized and the ratio of intensity can be customized arbitrarily by altering the space-dependent coupling strengths. Moreover, a one-way propagation feature is exhibited in the spatial coupler when an appropriate loss is introduced in the mediator WG owing to the existence of dark state. This work builds a bridge between quantum adiabatic technology and acoustic beam splitter, which may have potential applications in acoustic communication, filtering and detection.
Self-focusing of a q-gaussian laser beam under the influence of an exponential plasma density ramp in plasma
Authors: Butt Anees Akber , Kant Niti , Thakur Vishal
Published: March 2023

The goal of the current manuscript is to investigate how a plasma density ramp affects the ability of a q-Gaussian laser beam (q-GLB) to self-focus in plasma. The laser beam exhibits oscillatory self-focusing and defocusing behaviour with increasing distance of propagation. We used an exponential plasma density ramp to combat this defocusing tendency, allowing the particular laser beam to achieve a minimal spot size and nearly retain it up to several Rayleigh lengths. In addition to that, it has been observed that self-focusing increases with increasing q-values and the laser intensity. However, the lower values of q suggest strong self-focusing. By warily selecting the plasma and laser parameters, the density ramp could play a key role in the self-focusing of q-Gaussian laser. Self-focusing is seen to become stronger as propagation distance increases and the q-parameter affects the behaviour of the beam-width parameter in the plasma as shown.
Towards ordered Si surface nanostructuring: role of an intermittent ion beam irradiation approach
Authors: Rakhi  , Muñoz-García Javier , Cuerno Rodolfo , Sarkar Subhendu
Published: March 2023

The dynamical characteristics of surface nanopatterning using low-energy ion beams remains a central theme within ion beam sputtering. Most previous studies have focused on nanostructure evolution by bombarding surfaces using a continuous ion beam. Here, we study the effect of sputtering from an intermittent ion beam on nanopatterning of a Si surface, using a 900 eV or (mostly) 500 eV Ar+ ion beam at an incident angle of 67°, up to a total fluence of 10 × 1019 ions cm−2. Nanoripples are predominantly found on the irradiated surfaces, alongside a hierarchical triangular morphology at the lower energy condition. Ripple ordering is superior for intermediate values of the sputtering interval used in the intermittent sputtering approach. The area of the triangular structures also depends on the intermittent sputtering time intervals. At larger length scales than the ripple wavelength or the triangular structures, all surfaces display strong height fluctuations with a well-defined roughness exponent. Our results can be rationalized via known properties of the nonlinear regime of evolution for surfaces that become amorphous under irradiation and relax stress via ion-induced viscous flow, as borne out from numerical simulations of a continuum model previously proven to provide a significant description of the present class of experiments.
Effects of light size and intensity on photoconductive effect-based optically-induced dielectrophoresis for three-dimensional manipulation
Authors: Yang Huanzhou , Wang Zuobin
Published: March 2023

This study aims to study the effect of light size and intensity on photoconductive effect-based optically-induced dielectrophoresis (ODEP) for three-dimensional manipulation of cells. HL-7702 cells and SMMC-7721 cells in sucrose solution were manipulated three-dimensionally by ODEP. We found that the ODEP force generated by the three-dimensional non-uniform electric field will form a three-dimensional space, and the positive ODEP force will attract the cells near the space into it. When the number of cells is large, the three-dimensional stacking phenomenon will occur, that is, the three-dimensional assembly of cells. When the size of the light spot is similar to that of the cell, the projector with weak light intensity can only manipulate a single cell, while the laser with higher light intensity can carry out cell three-dimensional assembly. When the light intensity is similar, the larger size of light can produce larger a three-dimensional assembly space. So the cell three-dimensional manipulation by ODEP is achieved only when the photoconductive effect induced by the light pattern reaches the required intensity. The three-dimensional manipulation of cells by ODEP is from plane to stereo, and its realization is related to the light size and the photoconductive layer resistance determined by light intensity. And the three-dimensional space of assembling cells is related to the light size and intensity, and the larger and stronger the light, the larger the space.
The comparison of two-term Boltzmann approximation and Monte-Carlo solutions for e+Ar0 plasma
Authors: Tereshonok Dmitry , Chernyshev Timofey , Abramov Artem G , Ugryumov Aleksandr V
Published: March 2023

In this paper, we examine the energy distribution function of electrons in the case of a very weakly ionized argon plasma at sub-atmospheric pressure and external electric field using Boltzmann kinetic equation. We consider a spatially uniform model because our primary interest is the behavior of the collisional part of the equation. The purpose of the study is to compare two different numerical approaches: a deterministic one (using two-term local non-stationary approximation) and a stochastic approach (using the Monte Carlo method) over a wide range of reduced electric fields. We compare steady-state and time-dependent solutions, isotropic and anisotropic parts of the electron energy distribution function, and reaction constants. The research will also help to identify any limitations and challenges of these methods.
Modern methods of evaluation of metrological indicators of channels for measurement and processing of diagnostic values of traction power supply
Authors: Yakubov M , Sulliev A , Sanbetova A
Published: March 2023

This paper considers the matters of estimating errors in measuring and processing diagnostic values of power facilities of power supply of high-speed railways. An information model of the channel for measuring and processing measuring information has been developed, which makes it possible to analyze measurement errors against the background of disturbing external influences, time sampling and coding, signal comparison devices with settings for the lower and upper boundaries of the zone of normal values, as well as obtaining mathematical expectations, standard deviations and other numerical characteristics defining the regression analysis. Permissible error values of the measured parameters are determined for a given confidence level.
Study on a creation of highly ionized cold plasma at atmospheric pressure in the air
Authors: Balitsky V E , Muzafarov Sh , Kilichov O G , Togaev B K , Ruzikulov Z Z
Published: March 2023

This article analyzes the existing ways of creating cold plasma at atmospheric pressure directly into atmospheric air. Research areas listed turns out to be very valuable from a practical point of view, since allows you to create in the plasma gas enough intense ultraviolet radiation, as well as high concentration of physically and biochemically active particles (metastable atoms and molecules, radicals, ozone and other reactive compounds) relatively small specific energy costs. Further in the article, a theoretical comparative analysis of the processes of ozone electrosynthesis in electric sinusoidal and pulsed electric fields is given. The revealed advantage of pulsed electric fields is confirmed by the results of experimental studies
Simulation of linear asynchronous electric drive of slow-speed mechanisms of agricultural complex
Authors: Yunusov R F , Imomnazarov A B , Sattarov N E , Akbarov D A , Abduganiev A A
Published: March 2023

The agro-industrial complex includes a system of enterprises - the production of means of production for agricultural enterprises and various industries, as well as the sphere of processing, transportation and marketing of raw materials and finished products. The development of rational electric drives corresponding to the drive characteristics of production machines solves the problem of energy and resource saving. The methods are determined by the tasks to be solved in the study of an asynchronous electric drive motor.
Operating indicators in diesels with reduced heat and energy losses
Authors: Ismatov J , Aripdjanov M , Mirzaabdullaev J , Tillahodjaev R , Mirzaev A , Viarshyna H
Published: March 2023

The foregoing explains the experimentally established fact that in a heat-insulated diesel engine, diffusion combustion is of great importance - both in terms of the share of heat release and the duration of combustion. To compensate for the decrease in the efficiency of a thermally insulated diesel engine due to an increase in the duration of combustion, the injection advance is increased. The economic effect achieved in this way by increasing the maximum cylinder pressure cannot be considered due to thermal insulation. For typical compression end temperatures in a thermally insulated diesel engine, diffusion combustion, especially in the near-wall layers, is limited by transfer processes. This fact, in addition to the need to eliminate re-enriched zones in the near-wall layers, urgently requires additional turbulization of the working fluid during mixture formation and combustion in thermally insulated engines. The difficulty in solving this problem lies in the fact that one of the most important turbulence generators is the intake process, and one of the most effective solutions is special intake channels. However, the averaged motion and turbulence in the combustor decay significantly during compression. This process is enhanced in a thermally insulated diesel engine due to an increase in the molecular viscosity of the air. The same applies to the generation of turbulence at the end of compression-beginning of expansion. Thus, turbulization of the charge in the combustion chamber of a thermally insulated diesel engine is an urgent problem.
Study on selection of high yield cherry tomatoes varieties
Authors: Egamberdiyev S Y , Yunusov A S
Published: March 2023

Tomato is one of the main vegetable crops grown in greenhouses. It is grown in winter greenhouses in different autumn-winter, winter-spring, and transient and extended periods. This research aimed at researching high yield cherry tomatoes varieties. In this research, the study of tomato variety was done using “Methodology of state variety testing of agricultural crops”, “Methodology of field experiment” (Dospekhov A.B.), “Methodology of experimental work in vegetable growing and melon growing”, and “Guidelines for breeding varieties and hybrids of tomato for open and protected ground”. It was found that the length of the main stem of the tested hybrids increased from 25 to 104 cm on average 62 days after germination, and it was increased from 37 cm to 220 cm on the 80th day of observation. According to the results of 117 days of the observation, the samples were ranged from 48 cm to 269 cm. The pertinent results showed that a relatively high tasting score, which was 9.8 points, were observed in Honey cascade, 1000 N2 tomato and Balcony Yellow F1.
Description of the status of supply of hums and nutrient elements of desert pasture soils based on geoinformation systems
Authors: Namozov N , Saidova M , Kadyrova D , Rasulov Kh , Tursinbaev M
Published: March 2023

It is vitally important to increase the productivity of the degraded and low-fertility sandy desert soils in the world. In particular, special attention is being paid to the use of modern technologies aimed at quickly and qualitatively identifying the changes occurring in sandy desert soils, eliminating the negative effects of desert soils, and preventing the accelerated degradation processes in pastures through a comprehensive study of soil properties. In this research, GIS software was used to map humus and nutrient elements of desert pasture soils. The results showed that the amount of mobile phosphorus in sandy desert soils fluctuated in the range of 10-40 mg/kg in Nurota district, while in Konimekh district this indicator changed in the range of 17-40 mg/kg.
Septoria (Septoria pistaciae Desm.) pathogen infecting pistachio nuts in Uzbekistan and its biological characteristics
Authors: Nazarova O , Khujaev O , Jumanazarov G
Published: March 2023

This article introduces the results of research on the harmful effects of septoria, a fungal plant pathogen infecting pistachio, on pistachio fruit weight and yield. In recent years, there has been an increase in the negative effects of various diseases on the pistachio crop. Therefore, maintaining their yield and developing modern disease control measures remains one of our main goals. The measures to combat this disease and the effectiveness of the most suitable chemical preparations are presented below.
Planting rate of Sudan grass photosynthetic activity and dependence on the period of harvest
Authors: Mirsharipova G K , Mustafakulov D M
Published: March 2023

Since plants absorb solar energy with the help of their leaves, it is important to create plantations where the leaf area is optimal, which can be achieved by correctly determining the planting rate of crops and ensuring optimal thickness of seedlings. The objective of this research is to determine and justify optimum planting rate, which ensures a high yield of bluegrass in the saline soils of the Syrdarya region. During the research experiment, field experiments were conducted on the basis of “Methodology of State variety testing of agricultural crops” and “Methods of conducting field experiments”. The results showed that the leaf surface increased by 4.6 thousand m2/ha when the planting rate was 25 kg/ha, and it was noted that when the planting rate increased to 30 kg/ha, the leaf surface decreased by 0.7 thousand m2/ha compared to the previous option. Moreover, the total green yield was 65.6 and 2.7 q/ha compared to the yield obtained in the tuber phase.
Study of a mobile electric installation for the destruction of permanent rhizous weeds
Authors: Tashpulatov N T
Published: March 2023

This article presents the results of theoretical and experimental studies on the destruction of perennial rhizomatous weeds using the electric method. The biological features, vegetation, growth and development of weeds humai and pygmy beetle as an object of processing have been studied. The layout of the equipment for the installation for electropulse processing, the procedure for implementing the work process and the results of sexual research are described.
The content of phosphorus forms in calcareous irrigated serozems of the Tashkent region of Uzbekistan
Authors: Bairov A J , Juraev Sh A , Abdurakhmonov N Y , TNuriddinova Kh
Published: March 2023

In most cases, the irrigated soils of Uzbekistan provide low forms of phosphorus assimilated by plants due to their high fixation. Therefore, the bioavailability of P is one of the main factors limiting the yield of crops. The study aimed to identify the transformation of phosphorus in irrigated gray soils under the influence of the type of land use, age of development, and climate (location above sea level). For this purpose, the content of inorganic and organic pools of P was studied according to the Hedley method. The highest Pt values were noted in the soil of the Parkent region, where the amount of precipitation significantly exceeds that in other studied areas, as well as in the winterwheat-repeatedcrops-cotton (WW-RC-C) land use type with long-term use of high P fertilizer rates. In the studied soils, the share of Pi was 89-91%, while the share of Po was 9-11% of Pt. In the accumulation of labile P, in contrast to the accumulation of Pt, the greater availability of atmospheric precipitation and the WW-V type of land use, where the content of labile P. was significantly higher than in other studied soils. The obtained results indicate the need for individual consideration of the control of phosphorus nutrition of plants on soils used in various types of land use, their geographical location (altitude above sea level), and the age of development for agriculture, depending on the phosphate state of soils.
Mathematical processing of the influence of cotton storage conditions on yarn quality indicators
Authors: Ismatova M , Yuldasheva M
Published: March 2023

In this article, the qualitative indicators of yarn obtained from cotton fiber stored in a bundle of small sizes and volume were considered in order to determine its quality by processing the results of a full factorial experiment. Attention was also paid to the time spent on the experiment and the equipment used. Based on this and assuming the presence of a paired influence between the factors, the central compositional rototable planning of the experiment of the second order was adopted. The experimental study was planned to be carried out in two stages. A full-factorial experimental study was carried out on a small-sized spinning machine “Shirley” JSC “Scientific Center Pakhtasanoat” and yarn T-19.5 tex was produced. To determine the physical and mechanical properties of the threads, modern equipment of the testing laboratory “CentexUz” at TITLI was used. The results of a full-factorial experiment on the production of yarn from cotton fibers in a bundle of small sizes or volume are shown in tables 1-5, based on the results of the experiment, regression coefficients were found and equations were drawn up. According to the results, the threads of the 6th variant in terms of indicators were recognized as the best option.
Prospects for the development of fruit and vegetable production
Authors: Beglaev U , Dehkonova N , Rozikov J , Isakhanov M
Published: March 2023

Fruit and vegetable clusters are highly effective in finding and introducing innovations suitable for our regions and climate. This research intends to conduct an econometric analysis of the influence of factors on the productivity of vegetable products and fruit products. In this research, influence of factors on the level of productivity of vegetable products was analyzed. The results showed that the productivity index in 2022 was expected to be 249.8 q/ha, and it is predicted to be 10.5 q/ha or 4.4% more than the indicator in 2021. This increase was influenced by the increase in labor costs and fuel and lubricants consumption forecasts in 2022 was foreseen to increase from 6.8 percent to 12.6 than 2021.