Microsecond Range Research Articles

Superconducting flux qubit with ferromagnetic Josephson π-junction operating at zero magnetic field

Conventional superconducting flux qubits require the application of a precisely tuned magnetic field to set the operation point at half a flux quantum through the qubit loop, which complicates the on-chip integration of this type of device. It has been proposed that by inducing a π-phase shift in the superconducting order parameter using a precisely controlled nanoscale-thickness superconductor/ferromagnet/superconductor Josephson junction, commonly referred to as π-junction, it is possible to realize a flux qubit operating at zero magnetic flux. Here, we report the realization of a zero-flux-biased flux qubit based on three NbN/AlN/NbN Josephson junctions and a NbN/PdNi/NbN ferromagnetic π-junction. The qubit lifetime is in the microsecond range, which we argue is limited by quasiparticle excitations in the metallic ferromagnet layer. Our results pave the way for developing quantum coherent devices, including qubits and sensors, that utilize the interplay between ferromagnetism and superconductivity.

Design of a High-Power Nanosecond Electromagnetic Pulse Radiation System for Verifying Spaceborne Detectors

The Spaceborne Global Lightning Location Network (SGLLN) serves the purpose of identifying transient lightning events occurring beneath the ionosphere, playing a significant role in detecting and warning of disaster weather events. To ensure the effective functioning of the wideband electromagnetic pulse detector, which is a crucial component of the SGLLN, it must be tested and verified with specific signals. However, the inherent randomness and unpredictability of lightning occurrences pose challenges to this requirement. Consequently, a high-power electromagnetic pulse radiation system with a 20 m aperture reflector is designed. This system is capable of emitting nanosecond electromagnetic pulse signals under pre-set spatial and temporal conditions, providing a controlled environment for assessing the detection capabilities of SGLLN. In the design phase, an exponentially TEM feed antenna has been designed firstly based on the principle of high-gain radiation. The feed antenna adopts a pulser-integrated design to mitigate insulation risks, and it is equipped with an asymmetric protective loading to reduce reflected energy by 85.7%. Moreover, an innovative assessment method for gain loss, based on the principle of Love’s equivalence, is proposed to quantify the impact of feed antenna on the radiation field. During the experimental phase, a specialized E-field sensor is used in the far-field experiment at a distance of 400 m. The measurements indicate that at this distance, the signal has a peak field strength of 2.2 kV/m, a rise time of 1.9 ns, and a pulse half-width of 2.5 ns. Additionally, the beamwidth in the time domain is less than 10°. At an altitude of 500 km, the spaceborne detector records a signal with a peak field strength of approximately 10 mV/m. Particularly, this signal transformed into a nonlinear frequency-modulated signal in the microsecond range across its frequency spectrum, which is consistent with the law of radio wave propagation in the ionosphere. This study offers a stable and robust radiation source for verifying spaceborne detectors and establishes an empirical foundation for investigating the impact of the ionosphere on signal propagation characteristics.

Synthesis of low-dimensional metal halide CsAgCl2 for X-ray scintillation applications

Low-dimensional metal halides, which possess efficient luminescent properties, have garnered significant interest in the fields of optoelectronics and radiation detection. This study introduces novel lead-free silver-based metal halide material, CsAgCl2 microcrystals (MCs). These MCs have a one-dimensional atomic chain structure and a unique [AgCl5]4- tetragonal shared triangular configuration. CsAgCl2 MCs exhibit excellent performance as X-ray scintillators due to their bright broadband yellow emission and fast decay time in the microsecond range. The large Stokes shift of 350 nm is produced by self-trapped exciton emission. In X-ray scintillation applications, CsAgCl2 MCs demonstrate a high light yield of 13280 photons/MeV and a wide range of linear scintillation response. It is noteworthy that the CsAgCl2 MCs maintain good stability under both atmospheric conditions and continuous X-ray irradiation. The sample was used in an X-ray imaging screen, which clearly presented the X-ray projection image of a wooden stick. As a result, this research not only contributes to the collection of lead-free metal halide scintillators but also indicates that CsAgCl2 MCs have a wide range of future applications and potential in areas such as medical imaging, scientific research, and diagnostic and detection technologies.

The Effects of Bipolar Cancellation Phenomenon on Nano-Electrochemotherapy of Melanoma Tumors: In Vitro and In Vivo Pilot.

The phenomenon known as bipolar cancellation is observed when biphasic nanosecond electric field pulses are used, which results in reduced electroporation efficiency when compared to unipolar pulses of the same parameters. Basically, the negative phase of the bipolar pulse diminishes the effect of the positive phase. Our study aimed to investigate how bipolar cancellation affects Ca2+ electrochemotherapy and cellular response under varying electric field intensities and pulse durations (3-7 kV/cm, 100, 300, and 500 ns bipolar 1 MHz repetition frequency pulse bursts, n = 100). As a reference, standard microsecond range parametric protocols were used (100 µs × 8 pulses). We have shown that the cancellation effect is extremely strong when the pulses are closely spaced (1 MHz frequency), which results in a lack of cell membrane permeabilization and consequent failure of electrochemotherapy in vitro. To validate the observations, we have performed a pilot in vivo study where we compared the efficacy of monophasic (5 kV/cm × ↑500 ns × 100) and biphasic sequences (5 kV/cm × ↑500 ns + ↓500 ns × 100) delivered at 1 MHz frequency in the context of Ca2+ electrochemotherapy (B16-F10 cell line, C57BL/6 mice, n = 24). Mice treated with bipolar pulses did not exhibit prolonged survival when compared to the untreated control (tumor-bearing mice); therefore, the bipolar cancellation phenomenon was also occurrent in vivo, significantly impairing electrochemotherapy. At the same time, the efficacy of monophasic nanosecond pulses was comparable to 1.4 kV/cm × 100 µs × 8 pulses sequence, resulting in tumor reduction following the treatment and prolonged survival of the animals.

Spectral selectivity of luminescence of a copper ion-exchange layer in sodium-potassium-magnesium silicate glass

The bright luminescence of the copper ion-exchange layer in glass has potential applications as a converter of electric spark and corona discharge radiation in devices for the rapid analysis of metals because of its selectivity. The selectivity of the luminescence of the copper ion-exchange layer was achieved by the presence of different luminescent centers within it. In this work, the copper monomers, Cu+-Cu+ monovalent dimers, and Cun molecular clusters were formed in an ion-exchange layer of sodium-potassium-magnesium silicate glass (SiO2-Na2O-CaO-MgO-Al2O3-K2O-Fe2O3). The luminescence of the copper ion exchange layer was characterized by steady-state spectroscopy and time-resolved spectroscopy. Molecular copper clusters Cun exhibited luminescence in the nanosecond range, and Cu+ monomers and Cu+-Cu+ monovalent dimers in the microsecond range, respectively. At the same time the formation of divalent copper led to a limitation in the duration of ion exchange for the production of luminescent glasses. Heat treatment of the ion-exchange layers led to an increase in the concentration of molecular copper clusters, Cu+-Cu+ monovalent dimers, and Cu2+ divalent monomers.

Evaluating the motional timescales contributing to averaged anisotropic interactions in MAS solid-state NMR

Abstract. Dynamic processes in molecules can occur on a wide range of timescales, and it is important to understand which timescales of motion contribute to different parameters used in dynamics measurements. For spin relaxation, this can easily be understood from the sampling frequencies of the spectral-density function by different relaxation-rate constants. In addition to data from relaxation measurements, determining dynamically averaged anisotropic interactions in magic-angle spinning (MAS) solid-state NMR allows for better quantification of the amplitude of molecular motion. For partially averaged anisotropic interactions, the relevant timescales of motion are not so clearly defined. Whether the averaging depends on the experimental methods (e.g., pulse sequences) or conditions (e.g., MAS frequency, magnitude of anisotropic interaction, radio-frequency field amplitudes) is not fully understood. To investigate these questions, we performed numerical simulations of dynamic systems based on the stochastic Liouville equation using several experiments for recoupling the dipolar coupling, chemical-shift anisotropy or quadrupolar coupling. As described in the literature, the transition between slow motion, where parameters characterizing the anisotropic interaction are not averaged, and fast motion, where the tensors are averaged leading to a scaled anisotropic quantity, occurs over a window of motional rate constants that depends mainly on the strength of the interaction. This transition region can span 2 orders of magnitude in exchange-rate constants (typically in the microsecond range) but depends only marginally on the employed recoupling scheme or sample spinning frequency. The transition region often coincides with a fast relaxation of coherences, making precise quantitative measurements difficult. Residual couplings in off-magic-angle experiments, however, average over longer timescales of motion. While in principle one may gain information on the timescales of motion from the transition area, extracting such information is hampered by low signal-to-noise ratio in experimental spectra due to fast relaxation that occurs in the same region.

Comparative Effectiveness of Different Er:YAG Laser-Activated Irrigation Systems on Removing Calcium Hydroxide from Simulated Internal Root Resorption Cavities at Different Root Levels.

Objective: To investigate the effectiveness of Er:YAG laser-activated irrigation (LAI) with a short pulse duration for removing calcium hydroxide (CH) from simulated internal root resorption (IRR) cavities at three root levels. Background: Pulse duration is an important parameter during LAI, which ensures the efficiency of irradiation and the corresponding activation process. Short pulses in the range of a few microseconds enable rapid expansion and successive implosion of irrigants, resulting in distinct fluid movement. There have been few reports on CH removal efficacy from IRR cavities of different LAI systems, including those using short pulse duration. Methods: IRR cavities (1.6 mm diameter) were created at the apical, middle, and coronal root levels in 60 mandibular premolars and filled with a radiopaque CH paste. Samples were assigned to the following irrigation groups (n = 12, each): (1) LAI(P)-F, a prototype laser device that operates with short pulse duration (Morita Manufacturing) with a flat tip; (2) LAI(EA)-F, the ErwinAdverl laser device (Morita Manufacturing) with a flat tip; (3) LAI(EA)-T, the ErwinAdverl laser device with a tapered tip; (4) PIPS-T, the Lightwalker laser device (Fotona) with a tapered tip; and (5) SI, the syringe irrigation group. The laser tips were fixed at the canal entrance. The remaining CH volume and surface area were assessed in IRR cavities using micro-computed tomography and scanning electron microscopy, respectively. Data were statistically analyzed utilizing one-way analysis of variance and Tukey's test at 5% significance level. Results: The LAI(P)-F and PIPS-T groups exhibited the highest CH removal rates at three different levels (p < 0.05). The LAI(EA)-F group had a significantly better efficacy of CH removal compared with the LAI(EA)-T group at the middle level (p < 0.05). Conclusion: The LAI(P)-F and PIPS-T groups demonstrated superior efficiency in removing CH from simulated IRR cavities.

High-speed continuous X-ray imaging method based on SiPM auto-encoding detector

High-speed X-ray imaging can be used to observe the internal evolution of objects in the microsecond range. However, obtaining data and processing images continuously are difficult when the speed of X-ray imaging is more than one million frames per second (fps). The novel method of high-speed X-ray imaging, which is based on a SiPM auto-encoding detector, was proposed. The different response to X-ray is realized by adjusting the bias voltage of different pixels to encode the analog signals. The analog signals from multiple SiPM pixels are simplified into a single signal. In this way, SiPM is constructed as the SiPM auto-encoding detector, which greatly reduces the amount of analog signals to be sampled for each frame of X-ray image, and then the image is reconstructed in the upper computer. The feasibility of the imaging method was verified by coupling the pixelated SiPM and lutetium-ytterbium scintillation crystals to construct a SiPM auto-encoding detector. Six patterns were exposed when pulsed X-rays were performed at frequencies of 100 and 500 kHz. Then, the number of image pixels was compressed from 16 to 4. The peak signal-to-noise ratio of the reconstructed images was above 41, and the structural similarity was above 0.99. Experimental results demonstrated that the speed of continuous X-ray imaging reached 500, 000 fps for six kinds of 4 × 4 pixel patterns. This method can be applied to improve the speed of high-speed continuous X-ray imaging.

White-green photoluminescence of manganese(II) complexes with pyrazolo[1,5-a][1,10]phenanthroline-3-carbonitrile

Five manganese(II) complexes with a bidentate pyrazolo[1,5-a][1,10]phenanthroline-3-carbonitrile ligand (L) have been prepared and their structures have been determined. The anion effect on the structural diversity of the complexes has been studied using manganese(II) salts with different anions such as Cl¯, ClO4¯, and Ts¯. A reaction between manganese(II) chloride and L in organic solvents leads to complexes [MnL2Cl2]·xCH2Cl2 (1) and [Mn2L2(H2O)Cl4]·L (2), the use of manganese(II) tosylate in the rection yields in [MnL(H2O)3Ts]Ts·L·H2O (3) and [MnL(H2O)3Ts]Ts (4), and finally, in the case of manganese(II) perchlorate [MnL2(H2O)2](ClO4)2·L (5) is formed. According to the single-crystal X-ray analysis the coordination environment of the Mn(II) ions in the complexes is a distorted octahedron with MnN4Cl2 (1), MnN2O4 (3) and MnN4O2 (5) chromophores; the complex 2 is binuclear, in which two manganese atoms have different coordination geometries – distorted octahedron (MnN2Cl3O) and square pyramid (MnN2Cl3). Chloride ions are coordinated anions; perchlorate ions are in the outer coordination sphere. Tosylate ions can play both coordinating and non-coordinating roles in complexes. X-ray analysis shows that in 2 and 5 one molecule of L has no bonds with manganese atoms, and reveals only intermolecular interactions through π-π stacking. This leads to the formation of cocrystals [Mn2L2(H2O)Cl4]·L or [MnL2(H2O)2](ClO4)2·L, that affects the photophysical properties of these compounds. In order to compare the effect of L coordination on the photoluminescence properties of manganese(II) complexes, the complexes [Mn(phen)3](ClO4)2·xSolv with unsubstituted 1,10-phenanthroline have been synthesized. In contrast to [MnL2(H2O)2](ClO4)2·L, the 1,10-phenanthroline-based compound [Mn(phen)3](ClO4)2·H2O has no emission. Complexes 1, 3, 4 and 5 exhibit a white-green emission in the microsecond range with maxima at 530–565 nm in the solid state, and the photoluminescence properties of 5 are studied in solution.

Photophysics of singlet oxygen generation in chitosan films with viburnum fruit extract (Viburnum opulus L.) under the influence of plasmons on a modified titanium surface

Subject of study. This study investigates the luminescence spectral and kinetic features of singlet oxygen generation in chitosan microfilms (10 µm thick) embedded with an extract of viburnum fruit (Viburnum opulus L.). These films were deposited on both glass and gold film (80 µm thick), with the gold film electrochemically deposited on a rough, modified titanium surface. Aim of study. The aim was to determine the primary photophysical patterns of singlet oxygen dynamics in chitosan films containing viburnum fruit extract, following pulsed monochromatic photoexcitation by a structured titanium surface coated with electrochemically deposited gold. Method. The films were investigated in the visible and near-infrared regions using fluorescence techniques. The luminescence lifetime of Viburnum opulus L. flavonoids in the nanosecond range was measured using multichannel photon counting with a picosecond diode. The lifetime of the flavonoid triplet states and singlet oxygen phosphorescence in the studied extract in the microsecond range under excitation by a pulsed xenon lamp were also recorded. Main results. Long-lived delayed annihilation fluorescence of Viburnum opulus L. flavonoid molecules in the 590 nm spectral region, along with luminescence at 1272 nm attributable to singlet molecular oxygen, were observed. A comprehensive kinetic analysis was performed, considering the rate constants of photophysical processes involving singlet oxygen in films with viburnum fruit extract on rough gold surfaces under conditions of sample saturation with molecular oxygen. Stable generation of singlet oxygen was achieved in the chitosan microfilms containing viburnum fruit extract. Practical significance. The findings of this study can be applied to biological methods for cancer treatment.

X-ray photoelectron spectroscopy and NIR self-quenching emission behavior in Ho3+ doped YOF and V-YOF

Stoichiometric (YOF) and non-stoichiometric yttrium oxyfluoride (Y7O6F9) also known as the vernier phase (V-YOF) were investigated for possible optical applications. Both structures were prepared from a single source through the pyrolysis method. The V-YOF and YOF structures decomposed at 900 °C and 950 °C, respectively. X-ray photoelectron spectroscopy revealed four different yttrium sites in the V-YOF structure. The visible holmium ions emission doped in both consisted of three regions due to the 5S2,5F4 → 5I8, 5F5 → 5I8, and 5S2,5F4 → 5I7 transitions. The YOF structure's visible lifetime was also longer than in the V-YOF structure. The near-infrared photoluminescence emission originated from 5S2,5F4 → 5I6, 5I6 → 5I8 in both structures. The 5S2,5F4 → 5I6 near-infrared lifetimes for both decreased, indicating an energy transfer process. The 5I6 → 5I8 lifetime in both fluctuated due to the possibility of self-quenching through photon-trapping processes. The lifetimes were in the microseconds range.

Effects of Pulsed Electric Field on Meat Tenderization and Microbial Decontamination: A Review.

This review sought to categorize studies on meat tenderization and safety through pulsed electric field (PEF) treatment, with a particular focus on reconciling conflicting findings regarding the tenderization effect (i.e., the primary outcome of PEF treatment) and to discuss the underlying mechanisms of these effects. While the tenderization effect may vary depending on the homogeneity of PEF treatment and variations in the conditions of texture measurements, the protein associated with tenderization was degraded by PEF treatment in most studies. PEF technology enables the delivery of a high voltage for a brief duration, typically in the microsecond range, making it a non-thermal technology. One of the distinct advantages of PEF is its ability to preserve the freshness of meat due to its exceptionally short treatment time. While PEF studies have traditionally centered on pasteurizing liquid foods, research on its application to meat is steadily expanding. Therefore, this review aims to elucidate the mechanisms of PEF and provide current insights into the applications of this technology for meat tenderization and microbial inactivation.

Microsecond dynamics control the HIV-1 Envelope conformation.

The HIV-1 Envelope (Env) glycoprotein facilitates host cell fusion through a complex series of receptor-induced structural changes. Although remarkable progress has been made in understanding the structures of various Env conformations, microsecond timescale dynamics have not been studied experimentally. Here, we used time-resolved, temperature-jump small-angle x-ray scattering to monitor structural rearrangements in an HIV-1 Env SOSIP ectodomain construct with microsecond precision. In two distinct Env variants, we detected a transition that correlated with known Env structure rearrangements with a time constant in the hundreds of microseconds range. A previously unknown structural transition was also observed, which occurred with a time constant below 10 μs, and involved an order-to-disorder transition in the trimer apex. Using this information, we engineered an Env SOSIP construct that locks the trimer in the prefusion closed state by connecting adjacent protomers via disulfides. Our findings show that the microsecond timescale structural dynamics play an essential role in controlling the Env conformation with impacts on vaccine design.

Synthesis and photoluminescence properties of high color purity red emitting Li2MgTi3O8:Eu3+ phosphors for warm W-LEDs

In search of efficient and suitable phosphors for white light emitting diodes (w -LEDs), herein, we report Li2MgTi3O8:Eu3+ as red phosphors that are low-cost eco-materials synthesized by solid-state reaction method. XRD patterns confirm the crystallinity and phase purity of the as-prepared phosphors with the successful incorporation of Eu3+ ions. FTIR, FE-SEM and TEM were used to understand the functional groups and morphology of prepared samples respectively. The band gap energy calculated from DRS showed Burstein–Moss effect. Under 398 nm excitation, intense red emission was recorded at 615 nm and lifetime values were in microsecond range. The prepared phosphor possesses quantum efficiency of 31.74%, good thermal stability with an activation energy of 0.254 eV and exhibit warm red emission with 100% color purity. Therefore, the obtained results suggests that the prepared Li2MgTi3O8:Eu3+ phosphors can be considered as an appropriate candidate for the red component in w- LEDs.

Synthesis of Bimetallic Gold-Silver Nanoclusters and Its Application as Pb (II) Sensing Based on Fluorescence Technique

Much research has been done on gold nanoclusters stabilized by biomolecules because of their remarkable fluorescence properties and potential biological applications. Here, we synthesize bimetallic gold-silver nanoclusters in a protein template using Galvanic Exchange (GE) Method. The samples were analyzed using UV-visible spectroscopy, a fluorolog (fluorescence spectrometer), and a lifetime kit using Time-Correlated Single-Photon Counting method. It is found that the bimetallic gold-silver nanoclusters emit bright red fluorescence with a long fluorescence lifetime in the range of microseconds. The bimetallic gold nanoclusters were used for Pb (II) detection using fluorescence technique. The fluorescence intensity of nanoclusters increased as the concentration of added Pb (II) increased. This work suggests that bimetallic gold-silver nanoclusters can be used for Pb detection with a detection limit of 15 nmol/L and this sensing will contribute to providing clean water without Pb contamination.

Descriptive molecular pharmacology of the δ opioid receptor (DOR): A computational study with structural approach.

This work focuses on the δ receptor (DOR), a G protein-coupled receptor (GPCR) belonging to the opioid receptor group. DOR is expressed in numerous tissues, particularly within the nervous system. Our study explores computationally the receptor's interactions with various ligands, including opiates and opioid peptides. It elucidates how these interactions influence the δ receptor response, relevant in a wide range of health and pathological processes. Thus, our investigation aims to explore the significance of DOR as an incoming drug target for pain relief and neurodegenerative diseases and as a source for novel opioid non-narcotic analgesic alternatives. We analyze the receptor's structural properties and interactions using Molecular Dynamics (MD) simulations and Gaussian-accelerated MD across different functional states. To thoroughly assess the primary differences in the structural and conformational ensembles across our different simulated systems, we initiated our study with 1 μs of conventional Molecular Dynamics. The strategy was chosen to encompass the full activation cycle of GPCRs, as activation processes typically occur within this microsecond range. Following the cMD, we extended our study with an additional 100 ns of Gaussian accelerated Molecular Dynamics (GaMD) to enhance the sampling of conformational states. This simulation approach allowed us to capture a comprehensive range of dynamic interactions and conformational changes that are crucial for GPCR activation as influenced by different ligands. Our study includes comparing agonist and antagonist complexes to uncover the collective patterns of their functional states, regarding activation, blocking, and inactivation of DOR, starting from experimental data. In addition, we also explored interactions between agonist and antagonist molecules from opiate and opioid classifications to establish robust structure-activity relationships. These interactions have been systematically quantified using a Quantitative Structure-Activity Relationships (QSAR) model. This research significantly contributes to our understanding of this significant pharmacological target, which is emerging as an attractive subject for drug development.

Luminescent Behavior of Zn(II) and Mn(II) Halide Derivatives of 4-Phenyldinaphtho[2,1-d:1',2'-f][1,3,2]dioxaphosphepine 4-Oxide and Single-Crystal X-ray Structure Determination of the Ligand.

The two enantiomers of chiral phosphonate 4-phenyldinaphtho[2,1-d:1',2'-f][1,3,2]dioxaphosphepine 4-oxide, O=PPh(BINOL), were synthesized from the proper 1,1'-bi-2-naphtol (BINOL) enantiomer and characterized. The structure of the (S)-enantiomer was elucidated by means of single-crystal X-ray diffraction. The reaction with anhydrous ZnBr2 afforded complexes having the general formula [ZnBr2{O=PPh(BINOL)}2] that showed intense fluorescence centered in the near-UV region rationalized on the basis of TD-DFT calculations. The corresponding Mn(II) complexes with the general formula [MnX2{O=PPh(BINOL)}2] (X = Cl, Br) exhibited dual emission upon excitation with UV light, with the relative intensity of the bands dependent upon the choice of the halide. The highest energy transition is comparable with that of the Zn(II) complex, while the lowest energy emission falls in the red region of the spectrum and is characterized by lifetimes in the hundreds of microseconds range. Although the emission at lower energy can also be achieved by direct excitation of the metal center, the luminescence decay curves suggest that the band in the red range is possibly derived from BINOL-centered excited states populated by intersystem crossing.

Особенности применения установок Плазменный фокус в радиационном и космическом материаловедении

The features of the use of Plasma Focus (PF) devices in the field of radiation and space materials science related to the specific generation of several types of radiation in the working chambers of the PF are considered. It is noted that the main role in the damage and modification of the structural state of the surface layers of materials irradiated in the cathode zone of the PF working chamber is played by powerful pulsed beams of working gas ions and flows of high-temperature plasma in the nano- and microsecond range of pulse duration. It is shown that in addition to the common combined beam-plasma effect on a target sample, PF installations allow the possibility of separate irradiation of the target material with ion and plasma flows. Three methods for separating pulsed flows of hot plasma and fast ions in space and time in a PF installation, described in the literature, are presented. It is noted that PF installations are a promising tool for solving fundamental and applied problems in radiation and space materials science, including for simulation experiments focused on problems of thermonuclear energy and aerospace engineering. It is also indicated that hard X-ray pulses with a duration in the nanosecond range, arising from pulsed discharges in the PF chamber, can be used for diagnosing fast processes, in particular for non-destructive flaw detection of machines and mechanisms during their operation.

Effective networking: Enabling effective communications towards 6G

The realization of envisioned 6G use cases involving holographic and multi-sensory communications demand terabits per second data rates and latencies in the range of microseconds for an immersive experience. Concurrently, 6G’s hyper-intelligent IoT use cases require extremely low-latency and reliable communications at the network edge. To address these requirements, communications should be tailored to end-user goals. To this end, we study communication effectiveness, where a sender and receiver harness their computing capabilities and artificial intelligence, to maximize the impact of transmitted messages while sending fewer bits. On our model, the messages can get shorter as locally accumulated knowledge increases the targeted effect of the message. Hence, we describe a framework in which the accumulated knowledge can be aggregated and shared in a distributed manner. On a real-life use case, we showcase the potential reduction in the number of bits transmitted owing to the transferred accumulated knowledge. Finally, we explore future research directions in effective communications, considering technical, economical, and privacy considerations.

Pushing the heterometal doping limit while preserving long-lived charge separation in a Ti-based MOF photocatalyst

This study explores the nature, dynamics, and reactivity of the photo-induced charge separated excited state in a Fe3+-doped titanium-based metal organic framework (MOF), xFeMIL125-NH2, as a function of iron concentration. The MOF is synthesized with doping levels x = 0.5, 1 and 2 Fe node sites per octameric Ti-oxo cluster and characterized by powder x-ray diffraction, UV-vis diffuse reflectance, atomic absorption, and steady state Fe K-edge X-ray absorption spectroscopy. For each doping level, time-resolved X-ray transient absorption spectroscopy studies confirm the electron trap site role of the Fe sites in the excited state. Time scan data reveal multiexponential decay kinetics for the charge recombination processes which extend into the microsecond range for all three concentrations. A series of dye photodegradation studies, based on the oxidative decomposition of Rhodamine B, demonstrates the reactivity of the charge separated excited state and the photocatalytic capacity of these MOF materials compared to traditional heterometal-doped semiconductor photocatalysts.