Application of Heart Rate Acceleration Motion Wireless Sensor Fusion in Individual Special Competitive Sports

Heart rate monitoring is becoming more and more important in the development of modern health industry. At present, wireless sensor network equipment is mainly used to realize the real-time or periodic monitoring of human heart rate, so as to realize the health management of specific people. At the same time, the monitoring and analysis technology of heart rate is also widely used in special competitive sports. Through the real-time monitoring and analysis of athletes’ heart rate, we can feedback and analyze their corresponding competitive state in real time, so as to monitor the sudden state of athletes, and also provide a basis for the improvement of athletes’ later sports level. Based on this, this paper will use a single-chip microcomputer as the central data processing unit of the monitoring system at the hardware level, and inertial sensor and heart rate sensor at the sensor level. The system will design data acquisition module, motion positioning module, low-power module, athlete heart rate acquisition module, and motion state recognition module. Aiming at the low accuracy of traditional heart rate acceleration motion wireless sensor in competitive sports athletes’ heart rate recognition and motion state recognition, this paper innovatively proposes an athlete heart rate recognition algorithm based on acceleration signal, which extracts the frequency-domain characteristics of motion signal. The time-domain and time-frequency characteristics of athletes’ acceleration signal are used to realize the recognition of athletes’ sports state, and the power spectrum cancellation technology is used to realize the accurate detection of athletes’ heart rate. In order to verify the advantages of the hardware system and algorithm in this paper, three sports with quiet, dynamic, and random dynamic characteristics are selected for experimental verification. The experimental results show that the software algorithm proposed in this paper has obvious accuracy advantages in quiet and dynamic competitive sports compared with the traditional algorithm.

Internal and external catalysis in boronic ester networks

In dynamic materials, the reversible condensation between boronic acids and diols provides adaptability, self-healing ability, and responsiveness to small molecules and pH. Recent work has shown that the thermodynamics and kinetics of bond exchange determine the mechanical properties of dynamic polymer networks. However, prior studies have focused on how structural and environmental factors influence boronic acid–diol binding affinity, and design rules for tuning the kinetics of this dynamic bond are lacking. In this work, we investigate the effects of diol (or polyol) structure and salt additives on the rate of bond exchange, binding affinity, and the mechanical properties of the corresponding polymer networks. To better mimic the environment of polymer networks in our small-molecule model systems, we incorporated proximal amide groups, which are used to conjugate diols to polymers, and included salts commonly found in buffers. Using one-dimensional selective exchange spectroscopy (1D EXSY), we find that both proximal amides and buffering anions induce significant rate acceleration consistent with internal and external catalysis, respectively. This rate acceleration is reflected in the stress relaxation of gels formed using PEG modified with different alcohols, and in the presence of salts containing acetate or phosphate. These findings contribute to the fundamental understanding of the boronic ester dynamic bond and offer new molecular strategies to tune the macromolecular properties of dynamic materials.

Kinetic and Interaction Studies of Adenosine-5′-Triphosphate (ATP) Hydrolysis with Polyoxovanadates

The reactivity of polyoxovanadates towards adenosine-5′-triphosphate (ATP) hydrolysis at pH 2, 4, 6 and 7 is reported. Detailed kinetic investigation of ATP hydrolysis in the presence of polyoxovanadates was performed through multinuclear nuclear magnetic resonance (NMR) spectroscopy. In general, rate acceleration of up to five orders of magnitude was observed in the presence of vanadates compared to spontaneous ATP hydrolysis, with the greatest acceleration observed for reactions carried out at pH 2. Interestingly, the effectiveness of vanadates in promoting ATP hydrolysis decreased as the pH of the reaction solution increased; nevertheless, at pH = 7, the rate increase of one order of magnitude in comparison to blank reactions was still observed. Interactions between vanadate species in solution and ATP were investigated by means of 31P and 51V NMR spectroscopy, and this pointed towards the preferential interaction of vanadium with the phosphate groups rather than other regions of the ATP molecule.

Damage Function of a Quasi-Brittle Material, Damage Rate, Acceleration and Jerk during Uniaxial Compression: Model and Application to Analysis of Trabecular Bone Tissue Destruction

A diversity of quasi-brittle materials can be observed in various engineering structures and natural objects (rocks, frozen soil, concrete, ceramics, bones, etc.). In order to predict the condition and safety of these objects, a large number of studies aimed at analyzing the strength of quasi-brittle materials has been conducted and presented in publications. However, at the modeling level, the problem of estimating the rate and acceleration of destruction of a quasi-brittle material under loading remains relevant. The purpose of the study was to substantiate the function of damage to a quasi-brittle material under uniaxial compression, determine the rate, acceleration and jerk of the damage process, and also to apply the results obtained to predicting the destruction of trabecular bone tissue. In accordance with the purpose of the study, the basic concepts of fracture mechanics and standard methods of mathematical modeling were used. The proposed model is based on the application of the previously obtained differentiable damage function without parameters. The results of the study are presented in the form of plots and analytical relations for computing the rate, acceleration and jerk of the damage process. Examples are given. The predicted peak of the combined effect of rate, acceleration and jerk of the damage process are found to be of practical interest as an additional criterion for destruction. The simulation results agree with the experimental data known from the available literature.

Origin of Salt Effects in SN2 Fluorination Using KF Promoted by Ionic Liquids: Quantum Chemical Analysis

Quantum chemical analysis is presented, motivated by Grée and co-workers’ observation of salt effects [Adv. Synth. Catal. 2006, 348, 1149–1153] for SN2 fluorination of KF in ionic liquids (ILs). We examine the relative promoting capacity of KF in [bmim]PF6 vs. [bmim]Cl by comparing the activation barriers of the reaction in the two ILs. We also elucidate the origin of the experimentally observed additional rate acceleration in IL [bmim]PF6 achieved by adding KPF6. We find that the anion PF6- in the added salt acts as an extra Lewis base binding to the counter-cation K+ to alleviate the strong Coulomb attractive force on the nucleophile F-, decreasing the Gibbs free energy of activation as compared with that in its absence, which is in good agreement with experimental observations of rate enhancement. We also predict that using 2 eq. KF together with an eq. KPF6 would further activate SN2 fluorination.

Remote-controlled exchange rates by photoswitchable internal catalysis of dynamic covalent bonds

The transesterification of boronate esters with diols is tunable over at least 14 orders of magnitude. Rate acceleration is achieved by internal base catalysis, which lowers the barrier for the proton transfer step. Here we report a photoswitchable internal catalyst that tunes the rate of boronic ester/diol exchange over at least 4 orders of magnitude. We employed an acylhydrazone molecular photoswitch, which forms a thermally stable but photoreversible intramolecular H-bond, to gate the activity of the internal base catalyst in 8-quinoline boronic esters. The photoswitch can be cycled repeatedly, with high photostationary states. The intramolecular H-bond is found to be essential to the design of this photoswitchable internal catalyst, as protonating the quinoline with external sources of acid has little effect on the exchange rate.

Can Electric Fields Drive Chemistry for an Aqueous Microdroplet?

Reaction rates of common organic reactions have been reported to increase by one to six orders of magnitude in aqueous microdroplets compared to bulk solution, but the reasons for the rate acceleration are poorly understood. We investigate the role of electric fields at water droplet surfaces that might explain the promotion of unusual reactive chemistry, along with changes in electric field profiles as a function of excess charge to model the electrospray fragmentation process. We find that electric field alignments along free O-H bonds at the surface yield field strength distributions that are ~30 MV/cm larger on average than that found for O-H bonds in the interior of the water droplet, consistent with greater surface reactivity. We emphasize the importance of both nuclear and electronic effects at the surface, and the non-linear coupling of intramolecular solute polarization with intermolecular solvent modes, as a necessary feature for predicting the higher field strengths at water droplet surfaces.

Silica Supported Acids (SiO2-HClO4, SiO2-KHSO4) as Eco-friendly Reusable Catalysts for Bromination of Aromatic and Heteroaromatic Compoundsusing Kbr Under Solvothermal and Solvent-free Conditions

Silica supported nanogreenacids like Si-KHSO4, and Si-HClO4are explored as reusable catalysts for bromination of aromatic and hetero aromatic compounds using KBr under solvothermal, and solvent-free conditions. Reaction times reduced from Reacions under conventional solvothermal protocols conditions required (4 – 6) hours, while ultrasonic assisted reactions only (9 – 12) minutes for completion. But, solvent-free microwave assisted reactions required only (1-5) minutes exhibiting striking rate acceleration compared to the solvothermal and ultrasonic assisted protocols All the reaction protocols afforded fairly good yields of brominated products, which are comparable with existing protocols.