Progress in Data Transmission and Storage for Long Pulse Data Acquisition System

Since the study in the field of fusion has gradually developed toward the long-pulse experiment mode, long-pulse data has gradually become one of the main data types for pulsed experiments in the field of fusion. For long-pulse data, which is a kind of pulse-type data, it will be more difficult to transmit and store than short-pulse data because of its significant characteristics. In addition, in the design of data acquisition and control system (DACS) in fusion field, Experimental Physics and Industrial Control System (EPICS) has now gradually become the main framework of experimental control system to meet the diversity of devices and complexity of subsystems in large experimental system. However, due to the limitation of EPICS, its effectiveness in handling data transmission and storage under high speed data acquisition is not satisfactory. To solve the data transmission and storage under high-speed sampling, this paper proposes a data transmission and storage solution based on TCP/IP protocol and MDSplus database, which is designed with the concept of segmentation, i.e., data generated from experiments longer than 100 seconds are uploaded and stored in a segmented form. Currently, this system has been tested and applied, and the test result shows that the solution is feasible and the overall test system operates stably and reliably.

Intracellular Storage Reduces Stoichiometric Imbalances in Soil Microbial Biomass – A Theoretical Exploration

Microbial intracellular storage is key to defining microbial resource use strategies and could contribute to carbon (C) and nutrient cycling. However, little attention has been devoted to the role of intracellular storage in soil processes, in particular from a theoretical perspective. Here we fill this gap by integrating intracellular storage dynamics into a microbially explicit soil C and nutrient cycling model. Two ecologically relevant modes of storage are considered: reserve storage, in which elements are routed to a storage compartment in proportion to their uptake rate, and surplus storage, in which elements in excess of microbial stoichiometric requirements are stored and limiting elements are remobilized from storage to fuel growth and microbial maintenance. Our aim is to explore with this model how these different storage modes affect the retention of C and nutrients in active microbial biomass under idealized conditions mimicking a substrate pulse experiment. As a case study, we describe C and phosphorus (P) dynamics using literature data to estimate model parameters. Both storage modes enhance the retention of elements in microbial biomass, but the surplus storage mode is more effective to selectively store or remobilize C and nutrients according to microbial needs. Enhancement of microbial growth by both storage modes is largest when the substrate C:nutrient ratio is high (causing nutrient limitation after substrate addition) and the amount of added substrate is large. Moreover, storage increases biomass nutrient retention and growth more effectively when resources are supplied in a few large pulses compared to several smaller pulses (mimicking a nearly constant supply), which suggests storage to be particularly relevant in highly dynamic soil microhabitats. Overall, our results indicate that storage dynamics are most important under conditions of strong stoichiometric imbalance and may be of high ecological relevance in soil environments experiencing large variations in C and nutrient supply.

Controlling Intermolecular H-atom Abstraction with Ultrafast Pump-Push-Probe Spectroscopy

We utilize ultrafast multi-pulse pump-push-probe transient absorption spectroscopy and time-resolved photoluminescence to monitor excited-state H-atom transfer from hydroxylic compounds to the heptazine derivative 2,5,8-tris(4-methoxyphenyl)-1,3,5,6,7,9,9b-heptaazaphenalene (TAHz). The heptazine moiety is structurally related to the monomer unit of the ubiquitous organic polymeric photocatalyst, carbon nitride. We show that TAHz can photochemically abstract an H-atom from water, in addition to generating H2 in aqueous suspensions with photocatalytic activity matching that of carbon nitride. In our multi-pulse experiment, we use resonant pump pulse to photoexcite TAHz to a bright high-lying excited state, and after a relaxation period of roughly 6 ps, we use a NIR (1150 nm) pulse to “push” the chromophore to a higher-lying excited state. When phenol is present, the push induces a persistent decrease (ΔΔOD) in the initial excited-state absorption, indicating the push pulse engenders a divergence in the photochemical branching ratios. In the presence of electron-donating substituted phenols, the magnitude of ΔΔOD diminishes markedly due to the increased excited-state reactivity of the complex accompanied by the cathodic shift in the phenol oxidation potential. Thus, the H-atom abstraction appears to proceed without aid from the additional energy of the push pulse. These results reveal new insight into the branching ratio among unreactive localized heptazine excited states and reactive intermolecular charge transfer states of H-bonded heptazine chromophores. More generally, this work provides new insight into molecular design strategies to control the excited-state photochemistry of aza-aromatic materials toward important reactions such as H-atom abstraction from water.

Inrush Current Effects on SiC-MOSFETs for LLC Converter

We prototyped an LLC converter using SiC-MOSFET and GaN-FET to study the device dependence of the resonant type converter characteristics and high current effects on the devices during the start-up mode.Under steady state operation, no observable difference exists between the SiC-MOSFET and GaN-FET in current and voltage waveforms and energy conversion efficiency is over 96% regardless of the device used.However, significant differences exist during the start-up mode. As for the SiC-MOSFET, the inrush current is at maximum in the first few cycles and gradually decreases to steady state. As for the effects on the device, there are no characteristic changes or current waveform fluctuation during the start-up period even after 50 repetitions.Alternately, in the case of GaN-FET, the maximum inrush current is at the first cycle and decreases rapidly to half only a few cycles later. The multi-pulse experiment shows that a single high current pulse degrades the I-V characteristics of the device and the subsequent pulse current decreases. It is also noted that the degradation could be overcome by a longer interval after the high current, however, no further improvement is seen above a 20 µs interval.

Quantification of Uncoupled Spin Domains in Spin-Abundant Disordered Solids

Materials often contain minor heterogeneous phases that are difficult to characterize yet nonetheless significantly influence important properties. Here we describe a solid-state NMR strategy for quantifying minor heterogenous sample regions containing dilute, essentially uncoupled nuclei in materials where the remaining nuclei experience heteronuclear dipolar couplings. NMR signals from the coupled nuclei are dephased while NMR signals from the uncoupled nuclei can be amplified by one or two orders of magnitude using Carr-Meiboom-Purcell-Gill (CPMG) acquisition. The signal amplification by CPMG can be estimated allowing the concentration of the uncoupled spin regions to be determined even when direct observation of the uncoupled spin NMR signal in a single pulse experiment would require an impractically long duration of signal averaging. We use this method to quantify residual graphitic carbon using 13 C CPMG NMR in poly(carbon monofluoride) samples synthesized by direct fluorination of carbon from various sources. Our detection limit for graphitic carbon in these materials is better than 0.05 mol%. The accuracy of the method is discussed and comparisons to other methods are drawn.

Robot-aided Training of Propulsion During Walking: Effects of Torque Pulses Applied to the Hip and Knee Joints During Stance

The goal of this study is to evaluate the effects of the application of torque pulses to the hip and knee joint via a robotic exoskeleton in the context of training propulsion during walking. Based on our previous biomechanical study, we formulated a set of conditions of torque pulses applied to the hip and knee joint associated with changes in push-off posture, a component of propulsion. In this work, we quantified the effects of hip/knee torque pulses on metrics of propulsion, specifically hip extension (HE) and normalized propulsive impulse (NPI), in two experiments. In the first experiment, we exposed 16 participants to sixteen conditions of torque pulses during single strides to observe the immediate effects of pulse application. In the second experiment, we exposed 16 participants to a subset of those conditions to observe short-term adaptation effects.During pulse application, NPI aligned with the expected modulation of push-off posture, while HE was modulated in the opposite direction. The timing of the applied pulses, early or late stance, was crucial, as the effects were often in the opposite direction when changing timing condition. Extension torque applied at late stance increased HE in both experiments range of change in HE: (1.6 ± 0.3 deg, 7.7 ± 0.9 deg), p < 0.001). The same conditions resulted in a negative change in NPI only in the single pulse experiment — change in NPI for knee torque: −2.9 ± 0.3 ms, p < 0.001, no significant change for hip torque. Also, knee extension and flexion torque during early and late stance, respectively, increased NPI during single pulse application — range of change in NPI: (3.4, 4.2) ± 0.3 ms, p < 0.001). During repeated pulse application, NPI increased for late stance flexion torque — range of change in NPI: (4.5, 4.8) ± 2 ms, p < 0.001), but not late stance extension torque. Upon pulse torque removal, we observed positive after-effects in HE in all conditions. While there were no after-effects in NPI significant at the group level, a responder analysis indicated that the majority of the group increased both NPI and HE after pulse application.

Utilisation of JSI TRIGA Pulse Experiments for Testing of Nuclear Instrumentation and Validation of Transient Models

A pulse experiment model was validated in order to support future pulse experimental campaigns. All pulse experiments data was collected and are publicly available at http://trigapulse.ijs.si/. A comparison of the measured pulse physical parameters (maximal power, total released energy and full width at half maximum) and theoretical predictions (Fuchs-Hansen and the Nordheim-Fuchs models) was made.

Speech Rhythm Convergence as a Social Coalition Signal

Patterns of nonverbal and verbal behavior of interlocutors become more similar as communication progresses. Rhythm entrainment promotes prosocial behavior and signals social bonding and cooperation. Yet, it is unknown if the convergence of rhythm in human speech is perceived and is used to make pragmatic inferences regarding the cooperative urge of the interactors. We conducted two experiments to answer this question. For analytical purposes, we separate pulse (recurring acoustic events) and meter (hierarchical structuring of pulses based on their relative salience). We asked the listeners to make judgments on the hostile or collaborative attitude of interacting agents who exhibit different or similar pulse (Experiment 1) or meter (Experiment 2). The results suggest that rhythm convergence can be a marker of social cooperation at the level of pulse, but not at the level of meter. The mapping of rhythmic convergence onto social affiliation or opposition is important at the early stages of language acquisition. The evolutionary origin of this faculty is possibly the need to transmit and perceive coalition information in social groups of human ancestors. We suggest that this faculty could promote the emergence of the speech faculty in humans.

Polarizability of Aspirin at Terahertz Frequencies Using Terahertz Time Domain Spectroscopy (THz-TDS)

A novel application of terahertz time-domain spectroscopy (THz-TDS) is described for the determination of permittivity and polarizability of organic crystals, as exemplified by measurements with the polymorph I form of crystalline aspirin (acetylsalicylic acid). The coherent nature of the THz pulse experiment, coupled with gated-detection, permits direct measure of differences in the phase angle of the electric field vector after passing through a pellet composed of the aspirin crystals embedded within an inert polymer matrix. An effective media model is used to extract dielectric information for the crystals from the measured time-domain signal that is representative of the entire pellet composition. Polarizability is then obtained for these organic crystals by using the Clausius–Mossotti relationship. Dielectric spectra and polarizability spectra are presented over the 0.3–3 THz frequency range (10–100 cm−1). The average polarizability values measured over the low frequency range (10–20 cm−1) are 22.4 ± 0.3 and 22.4 ± 0.5 Å3 for aspirin crystals embedded within matrixes of polytetrafluoroethylene (PTFE) and polyethylene (PE), respectively.