Top Spin Research Articles

Dipolar induced nonreciprocal magnon hybridization in FeNi/YIG bilayers

We investigated the magnon hybridization behavior in FeNi films, which were deposited on the yttrium-iron garnet (YIG) films by using Brillouin light scattering. Nonreciprocal magnon hybridizations have been detected not only on the mode densities but also the dispersion relations. The perpendicular standing spin wave mode confined in the thickness direction hybridized with the top surface magnetostatic surface spin wave at smaller wave vectors range while hybridized with the bottom surface mode at larger wave vectors range. The dipolar interaction between the FeNi layer and the YIG layer should be the main reason for the nonreciprocal hybridization of the two modes in the FeNi layer. The nonreciprocal hybridization characteristics of FeNi/YIG double-layer magnetic films enrich the nonreciprocal magnon hybridization system and might have potential application in constructing spin wave-based devices.

Binned top quark spin correlation and polarization observables for the LHC at 13.6 TeV

We consider top-antitop quark (tt¯) production at the Large Hadron Collider (LHC) with subsequent decays into dileptonic final states. We use and investigate a set of leptonic angular correlations and distributions with which all the independent coefficient functions of the top-spin-dependent parts of the tt¯ production spin density matrices can be experimentally probed. We compute these observables for the LHC center-of-mass energy 13.6 TeV within the Standard Model at next-to-leading order in the QCD coupling including the mixed QCD weak corrections. We determine also the tt¯ charge asymmetry where we take in addition also the mixed QCD-QED corrections into account. In addition we analyze and compute possible new physics (NP) effects on these observables within effective field theory in terms of a gauge-invariant effective Lagrangian that contains the operators up to mass dimension six that are relevant for hadronic tt¯ production. First, we compute our observables inclusive in phase space. Then, in order to investigate which region in phase space has, for a specific observable, a high NP sensitivity, we determine our observables also in two-dimensional (Mtt¯,cosθt*) bins, where Mtt¯ denotes the tt¯-invariant mass and θt* is the top quark scattering angle in the tt¯ zero-momentum frame. Published by the American Physical Society 2024

Numerical Analysis of Tennis Serve Performance based on Aerodynamic Characteristics

Using the method of computational fluid dynamics, the influence of the spin axis angle of the tennis ball on the pressure distribution, lift coefficient and drag coefficient of the flow field around the tennis ball under three different serving styles, namely, flat stroke, topspin and sidespin, is investigated in depth. The results show that the lift coefficient of the tennis ball is significantly affected by the side spin serve, while the change of the lift coefficient is not obvious in the flat and top spin serves. In addition, for the drag coefficient, both topspin and sidespin serves had a significant effect on it, while the effect of the flat stroke was relatively small. It is worth noting that the changes in the spin axis angle did not lead to significant changes in the static pressure distribution on the surface of the tennis ball and the surrounding flow field under the three different serving styles. This finding is of great academic value and practical guidance for further understanding the hydrodynamic phenomena in tennis and for improving the serve technique.

Properties of the Top Quark

Recent measurements of the properties of the top quark at the CERN Large Hadron Collider are discussed. The results were measured for single and top quark pair production in their final states, including jets with either one or two leptons or only in hadronic final states. Top quark properties include angular correlations, top quark spin correlations, mass, and width. When looking towards the future, top quark properties open new and even interdisciplinary avenues for probing quantum information science.

The Influence of Training Methods and Eye-Hand Coordination Against the Results of Volleyball’s Top Serve Skills

This study aimed to determine: (1) differences in the effect of mass training methods and service distance manipulation methods on the results of volleyball topspin skills and (2) differences in volleyball topspin results with good and low hand-eye coordination. Eye-hand coordination on top spin volleyball skills and (3) training methods and hand-eye coordination on top spin volleyball skills. This research method used an experiment with a 2 x 2 factorial design, with a total of 42 people including coaches from the Citra Dara Volleyball Course Institute. The samples taken from this study were 22 people using a purposive sampling technique. The hand-eye coordination test and the volleyball serve test were used in the research instrument, along with the Russell-Lange volleyball serve test. Data analysis techniques using Anava. The results of this study indicate that: (1) there is a significant difference between the mass training method and the distance manipulation training method in the volleyball top spin results, and (2) there is a significant difference. the result of volleyball peak spin between coaches with high hand-eye coordination and low hand-eye coordination, and (3) training methods and upper server hand-eye coordination affect the results of the game volleyball service.

DIFFERENCES IN KINEMATIC PARAMETERS BETWEEN FIRST AND SECOND SERVES IN TENNIS BY ELITE PLAYERS OF THE GERMAN LEAGUE

The primary goal of this research was to determine the differences in kinematic parameters between the first and second serves in tennis among the elite players of the German league. The sample of respondents in this research consisted of 30 elite male senior players of the German League who have "Leistungklasse" from 1 to 7. The kinematic parameters that were analyzed are: Height of ball impact (KPVUL), Racket speed (KPBRE), Ball speed (KPBLO), The angle at the elbow joint of the arm that hits the ball (KPULZ), Oscillation of the vertical projection of the center of gravity of the body (KPOVP), Jump height (KPVSK), Ball launch height (KPVIL), The point of contact between the ball and the racket "sweetspot" (KPMLR), Ball rotation "Top spin" (KPRLO). The video recording required for kinematic analysis was acquired with two Casio EX-F1 digital cameras at a frequency of 200 images per second. The camera was placed at an angle of 900 in relation to the recording plane, and they were at a distance of 10 m. Space calibration was performed with the help of a calibration frame (200 x 200 cm). We have installed Zepp Tennis Smart Sensor 2.0 in the handle of the Wilson Pro Staff RF97 Autograph racket, using the Zepp Tennis application software. "Kinovea" software was used for service analysis and obtaining kinematic parameters from video recordings. By analyzing the results of the T-test for independent samples, it can be seen that there are statistically significant differences in five of the nine analyzed kinematic parameters : KPBRE – kinematic parameter of racket speed (Sig.=.000), KPBLO – kinematic parameter of ball speed (Sig.=.000), KPULZ – kinematic parameter angle in the elbow joint (Sig.=.000), KPMLR – kinematic parameter point of contact between the ball and the racket (Sig.=.000), as well as a variable KPRLO – kinematic parameter of ball rotation (Sig.=.000). Larger numeric values in variables: KPVUL – kinematic parameter ball impact height, KPOVP – kinematic parameter of oscillation of the vertical projection of the center of gravity of the body, KPVSK – kinematic parameter jump height and KPVIL – kinematic parameter ball impact height, show a difference but it is not enough to be statistically different. Key words: tennis, kinematic analysis, racket speed, Zepp sensor

Quantum entanglement and top spin correlations in SMEFT at higher orders

We present the first analysis of top spin polarizations, toverline{t} spin correlations, and toverline{t} spin entanglement at the LHC in the context of the Standard Model Effective Field Theory, that goes beyond Leading Order QCD accuracy. The complete set of independent dimension-6 operators entering toverline{t} production is identified, and their effects on all top spin observables are extracted at linear and quadratic order in c/Λ2. By comparing results at LO and NLO, we note that the inclusion of higher orders, while not dramatically changing the picture, often amounts to notable numerical differences, that are not fully captured by LO scale variation. We also find that the expected deviations from the SM have an intricate phase space structure, and show up predominantly at large top pT. For this reason, we advocate for the measurement of spin observables differentially or doubly-differentially in the toverline{t} phase-space. We show how the inclusion of present and future top spin measurements will improve global fits to top LHC data, by also addressing the issue of flat directions.

Serve capability level: float serve, jump float serve and jump serve top spin in the proliga final four female players

<em>This research is based on observations in the form of an analysis of the level of difficulty of the service performed by each player depending on the type of service used, such as floating service, jump float, and jumping service top spin. A good service is the direction of the ball to the empty side of the field or between two players. It is intended for when the opponent receives a service in a moving position or creates a misunderstanding between two players because the ball is between the two players. The service above is the type of service that is often done by players from the beginner level to the professional level. However, there are still many professional players who competed in the 2019 proliga, the first round of the women's sector, not all of them know what type of service is most productive. In accordance with the problem formulation, the purpose of this research is to determine the level of ability of floating service, jump float service and jumping service top spin in the final four proliga 2019 women's volleyball. This study uses a survey method with data collection techniques using observations (observations) by judges and document analysis (video). The conclusion from the overall final four women's volleyball matches in the 2019 proliga has a percentage result from each team regarding service ability, namely Service Floating ability with an average number of 38.83 and if presented in the form of a percentage that is 45.24%, Jump Float ability with an average number of 28.88 and if presented in the form of a percentage that is 33.64% and the ability of Jumping service Top Spin with an average number of 18.13 and if presented in the form of a percentage that is 21.12%</em>

The level of service ability in the final four 2019 pro league men's players

<strong><em>This research is based on observations in the form of an analysis of the level of difficulty of the service performed by each player depending on the type of service used, such as floating service, jump float, and jumping service top spin. A good service is the direction of the ball to the empty side of the field or between two players. It is intended for when the opponent receives a service in a moving position or creates a misunderstanding between two players because the ball is between the two players. The service above is the type of service that is often done by players from the beginner level to the professional level. However, there are still many professional players who competed in the 2019 proliga, the first round of the men's sector, not all of them know what type of service is most productive. In accordance with the problem formulation, the purpose of this research is to determine the level of ability of floating service, jump float service and jumping service top spin in the final four proliga 2019 men's volleyball. This study uses a survey method with data collection techniques using observations (observations) by judges and document analysis (video). The conclusion from the research that has been done is that the results of each team regarding service ability are the ability of floating service of 8.88 and if presented in percentage form, it is 11.27%, Jump float service ability is 33.63 and if presented in percentage form, it is 42, 65%, the ability to jump service top spin is 36.33 and if it is presented as a percentage, it is 46.08%. From the discussion, it was concluded that the level of service ability in the 2019 proliga men's volleyball final according to the results of observations and observations through video observations, it was concluded that the Jumping service Top Spin had the highest ability value compared to the service float and jump float of 46.08%. </em></strong>

Influence of expertise level on techniques of applying top and back spins in cue sports

ABSTRACT This study compared the kinematics of upper body and cue stick among players of various skill levels when performing back spin and top spin shots. Twenty-eight male cue sports players were assigned to the novice (n = 10), intermediate (n = 9), or skilled groups (n = 9). The back spin and top spin tests were administrated while kinematic data were recorded using a 3D motion capture system. The results revealed greater upper limb joint ranges of motions (all p < 0.05), maximum angular velocities (all p < 0.05), and cue tip speed in the back spin than top spin shots (p < 0.001). None of joint kinematic or shot performance variables investigated was significantly different among the three skill levels (all p > 0.05). For the head movement, the novice group exhibited greater anteroposterior displacement than the skilled group (p = 0.020). In conclusion, except for the head movement, the upper body and cue stick kinematics did not significantly differ among players with varied skill levels. Greater joint ranges of motions and angular velocities were required to generate a faster cue tip speed for the back spin shots when compared with the top spin shots.

Real time investigation of double magnetic tunnel junction with a switchable assistance layer for high efficiency STT-MRAM

This work reports experimental confirmation of the working principles of a double magnetic tunnel junction (DMTJ) to achieve highly efficient spin-transfer-torque (STT) switching. This concept uses a magnetically switchable assistance layer (ASL) acting as a top perpendicular spin polarizer. The STT-induced switching dynamics were described by macrospin simulations, while the magnetic and electrical properties of the devices were investigated in switching experiments. The reversal dynamics of the storage layer/ASL coupled system were validated by time-resolved measurements of the device resistance during write operation, confirming that the storage layer is subjected to additive STT contributions both from the reference layer and the ASL throughout its parallel-to-antiparallel and antiparallel-to-parallel transitions. The STT efficiency of the ASL-DMTJ was compared to that of single MTJ stacks comprising the same storage layer and no assistance layer. The figure of merit ∆/Ic (stability/critical current) was found to nearly double in devices of 80 and 100 nm diameter, with a smaller 30% increase obtained for 50 nm diameter cells.

Translational-rotational coupling during the scattering of a frictional sphere from a flat surface.

At a macroscopic level, concepts such as "top spin," "back spin," and "rolling" are commonly used to describe the collision of balls and surfaces. Each term refers to an aspect of the coupling of rotational motion during the collision of a spherical particle with a planar surface. In this paper, we explore the mechanisms of energy transfer involving the collision of a rotating sphere and a surface using a model of frictional interactions developed for a granular material. We present explicit analytical treatments for the scattering and derive expressions for two important limiting classes: energy conserving collisions and collisions subject to rapid transverse dissipation.

Effects of Power and Ballistic Training on Table Tennis Players' Electromyography Changes.

The aim of the present study was to analyze the effects of ballistic and power training on table tennis players’ electromyography (EMG) changes. Thirty male table tennis players, who were able to perform top spin strikes properly, were randomly assigned to three groups: power training (PT; n = 10); ballistic training (BT; n = 10); and no training (CON = control group; n = 10). PT and BT were performed 3 times weekly for 8 weeks. Before and after training programs, a one-repetition maximum test (1RM) and the EMG activity of all the subjects’ upper/lower body muscles while performing top spin strokes were analyzed. After training, significant interactions (group × time) were observed in increasing 1RM strength in upper/lower muscles (p < 0.05). However, neither training type had any significant effect on muscle EMG activity. These findings suggest that there should not necessarily be any significant change in the EMG signal after BT and PT despite the increase in muscle strength.

Acquiring Expertise in Precision Sport – What Can We Learn from an Elite Snooker Player?

Snooker can be an attractive life-long physical activity, given its popularity across all age groups in Asia and Europe. However, scientific research on the cueing movement is limited. This case study presented the biomechanical profiles of the cueing movement in an elite male snooker player (age 37 years old, height 173 cm, body mass 70 kg). Kinematics of the upper limb and cue stick, were examined in five selected snooker tasks (warm-up, stun, top spin, back spin, and stop shots) using the Vicon motion capture system. Ground reaction forces and centre of pressure characteristics were recorded using two Kistler force platforms. Results showed that the cueing movement was contributed primarily by elbow flexion/extension and much less wrist flexion/extension. The high degree of cue stick position overlap between the practice swing and final stroke indicated high level of cueing precision. Weight transfer between feet revealed a slight lean towards the left foot throughout the final stroke, confirming that the elite player was able to maintain high stance stability when executing the cueing movement. Results presented in the present study can serve as a reference for practitioners and scientists to detect error, enhance training, and improve performance in snooker. For practical applications, snooker players are advised to stabilise their shoulder during the cueing movement and deliver the cue stick primarily via elbow movements.

Kinematic Analysis of the Racket Position during the Table Tennis Top Spin Forehand Stroke

The present study aims to assess the position of the racket, and racket height with respect to the floor, during the table tennis top spin stroke. A stereophotogrammetric system (Smart-D, BTS, 8 cameras, 550 Hz) was used to track the table tennis racket during cross-court (CC) and long-line (LL) shots. Ten national level players completed ten CC and ten LL top spin strokes responding to a robot machine. The racket motion throughout the shot showed specific technical characteristics: the minimum height of the racket was detected during the backswing phase; racket height at the end of backswing phase (maximal distance racket/table) was higher than the minimum; height at the racket maximum velocity (ball/racket impact) was greater than the net’s height. Furthermore, the maximum height of the racket occurred at the end of the forward swing. No differences in these kinematic variables between CC and LL were found. Conversely, a higher inclination of the racket at the moment of maximum speed was detected in LL vs. CC. From a practical perspective, the present findings suggest that table tennis players need to introduce specific exercises in order to increase the height of the racket during the forehand top spin stroke, to improve its effectiveness.

Development of new 9-ball test protocols for assessing expertise in cue sports

BackgroundThis study aimed to develop new test protocols for evaluating 9-ball expertise levels in cue sports players.MethodsThirty-one male 9-ball players at different playing levels were recruited (recreational group, n = 8; university team, n = 15; national team, n = 8). A 15-ball test was administered to indicate overall performance by counting the number of balls potted. Five skill tests (power control, cue alignment, angle, back spin, and top spin) were conducted to evaluate specific techniques by calculating error distances from pre-set targets using 2D video analysis.ResultsIntra-class correlation analyses revealed excellent intra-rater and inter-rater reliability in four out of five skill tests (ICC > 0.95). Significant between-group differences were found in 15-ball test performance (p < 0.001) and absolute error distances in the angle (p < 0.001), back spin (p = 0.006), and top spin tests (p = 0.045), with the recreational group performing worst while the national team performing best. Greater inter-trial variability was observed in recreational players than the more skilled players (p < 0.005).ConclusionsIn conclusion, the 9-ball test protocols were reliable and could successfully discriminate between different playing levels. Coaches and researchers may employ these protocols to identify errors, monitor training, and rank players.

Effect of ballistic and power training on performance adaptations of élite table tennis players

The purpose of this study was to examine the effects of ballistic and power training on the skills, physical fitness and body composition adaptations of elite table tennis players. Thirty male table tennis players (age: 24 ± 7 years, stature: 175 ± 6 cm, body mass 74 ± 16 kg, percentage of fat mass (%FM) 12 ± 7%, mean ± SD), who were able to perform top spin strike properly, were randomly assigned to three groups: power training (PT), ballistic training (BT) and no training (Control, CON). PT and BT trained 3 times per week for 8 weeks. PT consisted of three sets for six different stations, 60–80% of one repetition maximum (1RM). BT consisted of three sets for five different throwing exercises. Pre- and post-intervention group comparisons were analyzed using a two-way ANOVA with repeated measurements of two factors (group × time). After training, significant interactions were observed in increasing muscle strength, muscle endurance, explosive power, anaerobic power, agility and grip strength regardless of the exercise methods (p 0.05). In conclusion, the results of the present study suggest that physical fitness adaptations can be increased similarly after 8 weeks of power and ballistic training, in table tennis players. So coaches and elite table tennis players can use ballistic and power training to improve their performance without having to worry about the negative impact of their training on their skill and explosive power performance.

The Effects of the Self-Talk Types and Task Complexity on the Accuracy of Forehand Topspin of Advanced Players

The purpose of this study is to determine the effects of the motivational and instructional self-talk and task complexity on the accuracy of forehand top spin of table tennis in advanced players. The 30 male advanced players were divided into 3 groups (2 experimental and 1 control). The task complexity was determined by color of ball and place of table placement. In other words, sequence sending of the ball were changed after two balls and this trend continues. The keywords for motivational self-talk were can do and I correctly recognize, and for Instructional self-talk “pay attention” and Close your paddle. Masters et. al test (2008) was used to measure the accuracy of forehand topspin. After the pre-test, subjects took part in 6 training sessions including 20 trails per session. After 48 hours, they participated in post-test. The data were analyzed by paired-samples t-test, one way ANOVA and Tukey post hoc test. Results showed that there is significant difference between the instructional and motivational self-talk in terms of task complexity. These findings suggested that instructional self-talk is the effective variable in performance of tasks that needs high complex decisions and accuracy.

The influence of auditory information on performance in table tennis

It is well-known that visual information is essential for anticipation in table tennis but it not clarified whether auditory cues are also used. Therefore, we performed two in-situ studies, in which novices (study A) and advanced players (study B) responded to strokes of a real opponent or a ball machine by returning with forehand counters (study A) and forehand top spins (study B) to a given target area on the table. We assessed the parameters “hit quality” and “subjective effort”. In study A, we provided four conditions: normal, a noise-cancelling headphone and earplugs to dampen auditory information, other noise-cancelling headphones and earplugs to remove almost all environmental sounds, and the same head-phones with additional bright noise to remove all sounds. In study B, we performed three tests (irregular play and regular play with an opponent and response to regular balls of a ball machine) under two conditions: normal and noise-cancelling headphones with the additional bright noise. In both studies, no significant differences between all conditions for “hit quality” and “subjective effort” (all p&gt;0.05) were found. We conclude that auditory information, as well as their volume, have no influence on the hit quality in table tennis for novices and advanced players.

DINAMICA PLANTAR EN PRUEBAS DE BALANCE, POTENCIA, VELOCIDAD, Y SERVICIO EN TENISTAS

The objective of this article is to describe the foot dynamics during the service and during the performance of specific tests of power, speed and balance in tennis players and to establish their relationship. A descriptive method was established and 16 athletes were evaluated in power, velocity, balance and top spin services tests. Descriptive measures were performed for the test results and for foot dynamics, and correlated with each other. The results suggest that the center of anteroposterior foot pressure (COP-AP) during the balance tests had an average of -32, the average power during the jump in the service was 165 +35. A relation (r = 0.45) was found between the time in the air and the centimeters jumped, in addition, between the time of the test of speed and the time of the cycle of the race (r = 0.54).