Phase Interval Research Articles

Adaptive Phase Estimation with Squeezed Vacuum Approaching the Quantum Limit

Phase estimation plays a central role in communications, sensing, and information processing. Quantum correlated states, such as squeezed states, enable phase estimation beyond the shot-noise limit, and in principle approach the ultimate quantum limit in precision, when paired with optimal quantum measurements. However, physical realizations of optimal quantum measurements for optical phase estimation with quantum-correlated states are still unknown. Here we address this problem by introducing an adaptive Gaussian measurement strategy for optical phase estimation with squeezed vacuum states that, by construction, approaches the quantum limit in precision. This strategy builds from a comprehensive set of locally optimal POVMs through rotations and homodyne measurements and uses the Adaptive Quantum State Estimation framework for optimizing the adaptive measurement process, which, under certain regularity conditions, guarantees asymptotic optimality for this quantum parameter estimation problem. As a result, the adaptive phase estimation strategy based on locally-optimal homodyne measurements achieves the quantum limit within the phase interval of [0,π/2). Furthermore, we generalize this strategy by including heterodyne measurements, enabling phase estimation across the full range of phases from [0,π), where squeezed vacuum allows for unambiguous phase encoding. Remarkably, for this phase interval, which is the maximum range of phases that can be encoded in squeezed vacuum, this estimation strategy maintains an asymptotic quantum-optimal performance, representing a significant advancement in quantum metrology.

Study on structure and viscosity evolution mechanism of titanium-containing iron liquid in full viscosity range

This study aims to investigate the relationship between the viscosity of Fe-4.5wt%C-0.2wt%Ti melt and its liquid structure. The actual experimental results of viscosity measurement reveal that the viscosity range of Fe-4.5wt%C-0.2wt%Ti melt can be segmented into three intervals. Through thermodynamically calculated equilibrium phases and high-temperature confocal experiments, it is observed that the abrupt change in viscosity in the lower temperature range is attributed to the precipitation of the graphite phase. Moreover, differential scanning calorimetry experiments exhibit a distinct phase transition in the liquid phase region. To delve into the atomic structure of the liquid phase region, molecular dynamics simulations are employed. The high-temperature liquid structure of Fe-4.5wt%C-0.2wt%Ti melt predominantly consists of vacancies, atomic clusters with Ti as the core, and atomic clusters with C as the core. Within the high-temperature liquid phase region, the conversion of Free-Fe and C1-Fe to Cx-Fe occurs, resulting in a reduction of free volume and enhanced stability of the cluster. Consequently, the inhomogeneity of the Fe-4.5wt%C-0.2wt%Ti melt increases, and the viscosity exhibits a significant increase with temperature, leading to a variation in the viscosity within the liquid phase interval.

Field Evaluation of Yellow Change and Red Clearance Intervals with Subsequent Permissive Left-Turn Flashing Yellow Arrow Indication

The flashing yellow arrow (FYA) indication has become commonly used for communicating permissive left-turn operations to road users. A conventional signal phasing communicated to left-turning drivers consists of a leading protected phase followed by a permissive phase using a FYA indication, often referred to as protected-permissive. To transition from the protected to the permissive phase, change (steady yellow arrow) and clearance (steady red arrow, all-red) intervals, or only a change interval, may be used. There is no specific guidance on the use of clearance intervals for left turns with protected-permissive phase and FYA indication. In this study, field data were collected from different geographical regions in the United States to evaluate change and clearance intervals with the objective of developing guidance. Video data were recorded at 37 intersections during peak hours, for approximately 142 h, across eight states. Overall, 4,001 observations of vehicles turning left during the change or clearance interval were analyzed. Field observations were evaluated at the approach level to assess left-turn violation rate and violations per cycle as a function of change and clearance interval configuration. At the individual vehicle level, logistic regression was implemented to evaluate the effect of change interval and clearance interval duration, delayed onset of FYA, and regional variation. The results of the analysis at the approach and individual vehicle level were consistent and indicate that: (i) a clearance interval should be included, (ii) delaying the onset of FYA indication with an extension beyond the all-red clearance interval would reduce left-turn signal violations, and (iii) duration of change intervals has a marginal impact on left-turn signal violations.

Meta‐atom design and communication prototype for wideband reconfigurable intelligent surface

AbstractExisting research on reconfigurable intelligent surfaces (RIS) has mainly focused on narrowband applications due to limitations in programmable metasurfaces and field prototype realization. This letter introduces a wideband RIS meta‐atom consisting of a single‐layer frequency selective surface supported by a dogbone‐shaped patch, ensuring a stable linear phase interval around the resonant frequency. A RIS communication prototype is constructed to evaluate its phase bandwidth upper limit and fundamental bandwidth properties. An equivalent circuit model is derived to predesign the wideband RIS meta‐atom, controlled by a varactor, and experimental validation in an anechoic chamber confirms its large bandwidth. Additionally, a wideband RIS‐assisted self‐contained prototype is demonstrated to illustrate the bandwidth characteristics and link gain enhancement at a system level. Test results indicate a researched bandwidth of up to 19.65%, with the 1‐bit RIS board achieving a 3‐dB gain bandwidth of about 8.62%.

Transient conjugate free convection within flexible enclosure having discrete heat source

Transient conjugate free convection in flexible enclosure is examined numerically. Isoflux heat sources are mounted in a left wall of finite thermal conductivity while a right wall is assumed to be hyper-flexible. The finite element method (FEM) is adopted to solve the governing partial differential equations, an arbitrary Lagrangian–Eulerian (ALE) approach inherent in the unstructured mesh. The governing parameters under consideration are: the number of the heat source, [Formula: see text], the thickness of the heat source, [Formula: see text], and the Rayleigh number, [Formula: see text]. It is determined that the development of conjugate convection heat transfer experiences through an initial phase, a transition phase, and a steady state phase. Each phase interval is shifted by adjusting the thickness of the heat source. Higher number and thicker of heat source cases had an ignorant effect on the shape of the flexible wall, but they tend to suppress the heat transfer rate. Increasing the block amplitude by 25% for [Formula: see text] results in reductions of the values of [Formula: see text] to 24%, 20%, and 28% respectively.

Experimental analysis of the TRC benchmark system.

The Tribomechadynamics Research Challenge (TRC) was a blind prediction of the vibration behavior of a thin plate clamped on two sides using bolted joints. Specifically, the natural frequency and damping ratio of the fundamental bending mode were requested as function of the amplitude, starting from the linear regime until high levels, where both frictional contact and nonlinear bending-stretching coupling become relevant. The predictions were confronted with experimental results in a companion paper; the present article addresses the experimental analysis of this benchmark system. Amplitude-dependent modal data was obtained from phase resonance and response controlled tests. In the phase resonance test, a resonant phase lag between response and excitation was ensured via feedback control, and the excitation level was step-wise in-/decreased. In the response controlled test, the response level was kept fixed via feedback control. An original variant of response controlled testing is proposed: Instead of a fixed frequency interval, a fixed phase interval is analyzed. This way, the high excitation levels required outside resonance, which could activate unwanted exciter nonlinearity, are avoided. The consistency of the nonlinear modal testing methods, with each other, and with conventional linear tests at low amplitudes, is carefully analyzed. Comparisons of nonlinear-mode based predictions with direct frequency response curve measurements (at fixed excitation level) serve as additional cross-validation. Overall, these measures have enabled a high confidence in the acquired modal data. The different sources of the remaining uncertainty were further analyzed. A low reassembly-variability but a moderate time-variability were identified. The latter is attributed to some thermal sensitivity of the system. Two nominally identical plates were analyzed, which both have an appreciable initial curvature, and a significant effect on the vibration behavior was found depending on whether the plate is aligned/misaligned with the support structure. Further, a 1:2 nonlinear modal interaction with the first torsion mode was observed, which only occurs in the aligned configurations. All data (time series of nonlinear tests; linear modal properties) and post-processing methods are publicly available.

Use of Mathematical Modeling Tools to Support Decision-Making in Medicine

This research paper focuses on the development of advanced mathematical models for disease diagnosis and prediction, and the subsequent creation of automated systems based on these models. These systems leverage a range of mathematical models and incorporate cutting-edge information technology achievements to provide medical professionals with valuable decision-making support. By amalgamating mathematical rigor and technological innovation, this research endeavors to enhance the accuracy and efficiency of medical diagnoses, thereby improving patient care and healthcare outcomes. This study delves into the persistent need for contemporary information systems, where information plays a crucial role in decision-making. It aims to provide an objective approach to addressing pressing medical challenges, particularly in disease diagnosis and prediction, enhancing the effectiveness of these critical tasks. Automated medical information systems, built on advanced mathematical models, significantly empower physicians. Machine diagnostics, relying on deterministic logic, the phase interval method, and information-probabilistic logic, bolster diagnostic capabilities. Functional entropy enables individuals to handle vague information, aiding decision-making. Assessing imprecision and uncertainty computationally diminishes subjectivity, while employing fuzzy set theory enhances diagnostic modeling. Mathematical models assess diagnostic indicators, and linguistic variables quantify resemblance. The diagnostic model for primary biliary cirrhosis and active hepatitis utilizes a diagnostic table and gradient projection. This comprehensive study advances medical diagnostics through mathematical models and automated systems, addressing critical healthcare challenges.

Decomposing the Spectrum of Ultraluminous X-Ray Pulsar NGC 300 ULX-1

A phase-resolved analysis on the X-ray spectrum of ultraluminous X-ray pulsar (ULXP) NGC 300 ULX-1 is performed with data taken with XMM-Newton and NuSTAR on 2016 December 16. In addition to the classical phase-restricting analysis, a method developed in active galactic nuclei studies is newly employed for ULXP. It has revealed that the pulsation cycle of the source can be divided into two intervals in terms of X-ray variability. This suggests the rotating flow consists of at least two representative emission regions. Furthermore, the new method successfully decomposed the spectrum into an independent pair in each interval. One is an unchanging-component spectrum that can be reproduced by a standard disk model with a km inner radius and a 0.25 ± 0.03 keV peak temperature. The other is the spectrum of the component that coincides with the pulsation. This was explained with a Comptonization of a keV blackbody and exhibited a harder photon index in the brighter phase interval of two. The results are consistent with a picture that the pulsating emission originates from a funnel-like flow formed within the magnetosphere, and the inner flow exhibiting a harder continuum is observed exclusively when the opening cone points to the observer.

Nonlinear phase error correction method based on multi-grayscale coding.

Fringe projection profilometry is a non-contact and highly efficient 3D measurement technique widely used in various applications. However, the nonlinear intensity response of digital projectors affects measurement accuracy. While increasing the number of fringe projections can reduce the errors caused by nonlinear problems, it significantly prolongs the measurement time. In order to improve both accuracy and speed simultaneously, a nonlinear phase error correction method based on multi-grayscale coding is proposed. The intensity response curve of the system is fitted by the grayscale images, and then the grayscale values of the phase-shifting fringe images are corrected to reduce the nonlinear error. In order to reduce the number of fringe projections and speed up the measurement, the multi-grayscale coding method is used to divide the phase interval by the order of the gray values of the same pixel in multiple grayscale images. The experimental results validate the efficacy of the proposed multi-grayscale coding method. An accurate phase calculation is achieved, and a single reconstruction can be achieved with only seven photos. After the nonlinear correction, the phase accuracy of the three-step phase-shifting algorithm is increased by 50.77%, and the reconstruction accuracy of the standard ball is increased by 46.38%.

Improved Deep Reinforcement Learning for Intelligent Traffic Signal Control Using ECA_LSTM Network

Reinforcement learning is one of the most widely used methods for traffic signal control, but the method experiences issues with state information explosion, inadequate adaptability to special scenarios, and low security. Therefore, this paper proposes a traffic signal control method based on the efficient channel attention mechanism (ECA-NET), long short-term memory (LSTM), and double Dueling deep Q-network (D3QN), which is EL_D3QN. Firstly, the ECA-NET and LSTM module are included in order to lessen the state space’s design complexity, improve the model’s robustness, and adapt to various emergent scenarios. As a result, the cumulative reward is improved by 27.9%, and the average queue length, average waiting time, and CO2 emissions are decreased by 15.8%, 22.6%, and 4.1%, respectively. Next, the dynamic phase interval tgap is employed to enable the model to handle more traffic conditions. Its cumulative reward is increased by 34.2%, and the average queue length, average waiting time, and CO2 emissions are reduced by 19.8%, 30.1%, and 5.6%. Finally, experiments are carried out using various vehicle circumstances and unique scenarios. In a complex environment, EL_D3QN reduces the average queue length, average waiting time, and CO2 emissions by at least 13.2%, 20.2%, and 3.2% compared to the four existing methods. EL_D3QN also exhibits good generalization and control performance when exposed to the traffic scenarios of unequal stability and equal stability. Furthermore, even when dealing with unique events like a traffic surge, EL_D3QN maintains significant robustness.

Development of a Thai naming application for clients with aphasia

Background: Aphasia, as brain damage resulting from a stroke, results in language impairment, including speaking, auditory comprehension, reading, and writing. Modern technology enhances self-administered recovery training, allowing clients to restore and improve communication. Objectives: This study developed and assessed the effectiveness of an application on Android mobile devices for language rehabilitation with an emphasis on picture naming. Materials and methods: A small sample research design was conducted with five primary caregivers and five clients with aphasia. The study was divided into two steps: application development and implementation using a single-subject experimental research design. This research design was divided into three phases: (1) Phase A1, a baseline of 2 weeks before applying the training; (2) Phase B, a training period of 6 weeks; and (3) Phase A2, a withdrawal period of 4 weeks. The total study period was 12 weeks. Results: The naming rehabilitation application was assessed by visual graphical data analysis, with differences analyzed at each phase interval. After using the application for six weeks, the naming scores of the participants as clients were measured by the Thai Adaptation of the Western Aphasia Battery test (WAB). Results showed increased naming scores while the clients developed their naming skills using the application. Conclusion: This application enhanced the clients’ naming skills and reduced the time taken to name the words when conducting repetitive stimulation exercises in the form of intensive training combined with various cueing techniques. This application promoted the ability of clients with word-finding difficulties to retrieve words.

Efficacy of Intravaginal Administration of Isosorbide Dinitrate Together with Misoprostol versus Misoprostol Alone in Induction of Labor

Background Cervical ripening is a complex process involving extensive remodeling and dynamic anatomic and physiologic alternations governed by hormonal changes, inflammatory responses, vasodilatory changes, and other biological processes. Prostaglandins, produced both locally in the cervix and uterus as well as originating from the fetal membranes, play a critical role in cervical ripening and uterine contractility by increasing inflammatory mediators in the cervix and inducing cervical remodeling. Objective To assess the adjunctive Role of intravaginal administration of Isosorbide dinitrate in induction of labor. Patients and Methods This randomized controlled clinical trial was conducted at tertiary care hospital at Ain Shams University Maternity hospital (labor ward) and was randomly selected from full term patients attending the labor ward and scheduled for induction of labor. Results Our results revealed that the need to cesarean section was statistically significantly less frequent among Isosorbide dinitrate group. Our results revealed that the duration of induction to active phase interval and the duration of active stage of labor were significantly shorter among Isosorbide dinitrate group than among Control group. Conclusion As evident from the current study, both intravaginal misoprostol and combination of vaginal Isosorbide dinitrate and misoprostol are safe and effective modes of labor induction. Vaginal isosorbide dinitrate and misoprostol is more effective than misoprostol alone in terms of post induction Bishop Score, shorter induction to active phase interval and induction to delivery interval. Thus, the combined use of vaginal isosorbide dinitrate with misoprostol for preinduction cervical ripening at term may prove to be a major therapeutic advance.

Comparison of the cytokine responses to acute strength exercise between oral contraceptive users and naturally cycling women

PurposeCytokines are released as part of an inflammatory reaction in response to strength exercise to initiate muscle repair and morphological adaptations. Whether hormonal fluctuations induced by the menstrual cycle or oral contraceptives affect inflammatory responses to strength exercise remains unknown. Therefore, we aimed to compare the response of cytokines after acute strength exercise in naturally menstruating women and oral contraceptive users.MethodsNaturally menstruating women (MC, n = 13, 24 ± 4 years, weekly strength training: 4.3 ± 1.7 h) and women using a monophasic combined pill (> 9 months) (OC, n = 8, 22 ± 3 years, weekly strength training: 4.5 ± 1.9 h) were recruited. A one-repetition-maximum (1RM) test and strength exercise in the squat (4 × 10 repetitions, 70%1RM) was performed in the early follicular phase or pill free interval. Concentrations of oestradiol, IL-1β, IL-1ra, IL-6, IL-8, and IL-10 were assessed before (pre), directly after (post) and 24 h after (post24) strength exercise.ResultsIL-1ra increased from pre to post (+ 51.1 ± 59.4%, p = 0.189) and statistically decreased from post to post24 (– 20.5 ± 13.5%, p = 0.011) only in OC. Additionally, IL-1β statistically decreased from post to post24 (– 39.6 ± 23.0%, p = 0.044) only in OC. There was an interaction effect for IL-1β (p = 0.038) and concentrations were statistically decreased at post24 in OC compared to MC (p = 0.05). IL-8 increased across both groups from post to post24 (+ 66.6 ± 96.3%, p = 0.004).ConclusionWe showed a differential regulation of IL-1β and IL-1ra between OC users in the pill-free interval and naturally cycling women 24 h after strength exercise, while there was no effect on other cytokines. Whether this is associated with previously shown compromised morphological adaptations remains to be investigated.

Digital phase shift based simulated coherence phase demodulation technology for [formula omitted]-OTDR

In this paper, we propose a digital phase demodulation scheme for phase-sensitive optical time-domain reflectometer (Φ-OTDR) systems based on simulated coherence for digital phase shift, in which three-path signals with a phase interval of 120° can be obtained by employing digital simulated orthogonal coherence for phase shift instead of using a hardware 3×3 coupler and three detectors, while the high-frequency component can be eliminated through cross differential between simulated coherence signals. On this basis, the phase variation of Rayleigh backscattering (RBS) light can be analyzed by differential cross multiplication (DCM). The performance of the proposed scheme is evaluated through experiments by detecting a series of vibration signals with various sensing distances, vibration frequencies, and waveforms. The experimental results demonstrate that the phase variation caused by external vibration can be effectively reconstructed and a strain resolution of 0.5 nɛ and the SNR of 51.03 dB can be achieved through the proposed demodulation method, which significantly simplifies the system and effectively suppresses the deviation of phase interval and noise caused by hardware demodulation.

Multidisciplinary Studies of the Thyroid Gland’s Synthetic Activity under Conditions of Iodine Deficiency Using Correlation Analysis

The article examines the results of a multidisciplinary study of the thyroid follicular cells’ synthetic activity of male albino rats using the author’s methods for determining the profiles of hormonopoietic cells’ special capacities and semi-quantitative analysis of electronograms, a package of mathematical methods using the principle of fuzzy logic, the cluster approach to grouping data, the principle of phase interval, correlation analysis using Pearson’s formula and evaluating the results according to the Chaddock scale, interpreting the obtained results from the standpoint of cytophysiology. A comparative study on the effect of low, moderate, and high doses of organic and inorganic iodine on changes in correlations between protein-synthesizing organelles of follicular cells under conditions of dietary iodine deficiency was carried out. Based on the data on the number, strength and direction of correlations, a comparative study on the effect of low, moderate, and high doses of organic and inorganic iodine on the thyroid follicular cells’ protein-synthesizing organelles under conditions of dietary iodine deficiency was carried out. The information on the peculiarities of thyroid hormonopoiesis under the action of iodine of different chemical nature was deepened and the greater activating effect of organic iodine was proved, which is of scientific interest and has practical significance for the development of personalized preventive measures for dietary iodine deficiency.

A Metal-Only Folded Reflectarray Antenna

This paper presents a metal-only folded reflectarray antenna (MOFRA), consisting of three components, namely a pyramidal feed horn, a lower reflectarray, and an upper polarizer, which are all made of metal. The lower reflectarray consisting of planar polarization rotation elements focuses the beam and twists the incoming wave polarization perpendicularly so that the reflection wave can pass through the upper polarizer. With the adjustment of geometrical size, four elements with an equal phase interval of 45° are achieved. In addition, along with their mirror counterparts, 3-bit phase shifting elements covering 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315° within 9-10.6 GHz can be realized. For validation, a metal-only folded reflectarray with 610 elements is built and tested. Based on experiment results, 1-dB gain bandwidth is 16% while the peak aperture efficiency is 45%. These promising properties together with the low-profile metal-only structure make the proposed design a great candidate for space applications.

Diagonal-couplet gaits on discontinuous supports in Japanese macaques and implications for the adaptive significance of the diagonal-sequence, diagonal-couplet gait of primates.

Diagonal-sequence, diagonal-couplet (DSDC) gaits have been proposed as an adaptation to travel on discontinuously arranged arboreal branches. Only a few studies have examined primate gait adjustment to support discontinuity. We analyzed the gaits of Japanese macaques walking on the "ground" and two discontinuous conditions, "circle" and "point," to better understand the advantages of DSDC gaits on discontinuous supports. Seventy-eight vertical posts, each with a circular upper surface, were arranged in four rows at a spacing of 200 mm. The diameter of the circular upper surface was 150 mm ("circle condition") or 50 mm ("point condition"). We calculated the limb phase, duty factor, and time interval from hindlimb touchdown to ipsilateral forelimb liftoff. The supports the fore- and hindlimbs landed on during walking were identified in the circle and point condition. The macaques predominantly used DSDC gaits in the ground and circle conditions and lateral-sequence, diagonal-couplet (LSDC) gaits in the point condition. The macaques usually placed their hindlimbs on the same supports as their ipsilateral forelimbs during the gait cycle. Japanese macaques overlapped the ipsilateral fore- and hindlimb stance phase in all DSDC and some LSDC gaits to proximate the ipsilateral limbs on the discontinuous support, allowing the forelimb to guide the hindlimb placement to the support. The overlap duration of the ipsilateral limb stance phases may be extended by DSDC gaits longer than by LSDC gaits, allowing for a direct pass of the support being held by the prehensile hand to the prehensile foot.

Fluorination Improves the Electro-Optical Properties of Benzoxazole-Terminated Liquid Crystals in High Birefringence Liquid Crystal Mixtures: Experimental and Theoretical Investigations.

Aromatic heterocyclic liquid crystal (LC) materials have received much attention from LC chemists for their high birefringence and large dielectric anisotropy, yet few have reported their properties in LC mixtures. In this work, a series of fluorinated benzoxazole liquid crystal compounds were synthesized to evaluate their electro-optical properties in high birefringence LC mixtures, with the expectation of further establishing the theoretical basis and experimental evidence for their applications in LC photonics. Firstly, the effects of the lateral fluorine substituent positions on the molecular synthetic yield, mesomorphic and solubility properties were comparatively investigated. Afterwards, we focused on the fluorination effects on the core electro-optical properties, including birefringence, dielectric anisotropy and further investigation of the viscoelastic coefficient of high birefringence LC mixtures. Research results showed that the benzoxazole liquid crystal compounds possess low melting points, wide nematic phase intervals and good solubility by appropriate lateral fluorine substitution, which is beneficial to further improve the electro-optical properties of high birefringence LC mixtures. Meanwhile, the theoretical and experimental results corroborate each other to well reveal the structure-property relationship. This study demonstrates that fluorination would promote promising applications of benzoxazole-terminated liquid crystals in emerging LC optical devices.

PD Characteristics and Parameter Extraction for EPR Cable Terminal in EMUs With Spike Defect at Low Temperature

Ethylene propylene rubber (EPR) cable terminals are widely used in high-speed railway trains. In the alpine environment, partial discharge (PD) and even breakdown failures caused by spike defects frequently occur in EPR cable terminals. To study the discharge development of cable terminals with spike defects in alpine regions, EPR cable terminal test samples with spike defects were made, and a low-temperature PD test system was built to simulate the environmental conditions in alpine regions. The characteristics of the lower PD spectrum were analyzed, and the influence mechanism of low temperature on the discharge activity was analyzed combined with the scanning electron microscope (SEM) scan. The research results show that the discharge development of the terminal spike defect can be divided into three stages: S1~S3. In S1 stage, the degree of PD at –30°C is weaker than that at 20°C dues to the low diffusion ability and weak polarization effect of carriers. In S2 and S3 stages, with the continuous discharge, low temperature makes the deterioration tolerance of ethylene propylene rubber material decrease more seriously, which promotes the development of discharge. The discharge phase interval is larger and the discharge activity is more intense at –30°C than at 20°C, and the breakdown time point is 11.6% earlier. By studying the characteristics of the spectrum, it is found that the deviation of PD φ- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q_ave</i> spectrum at –30°C from positive to negative is an important signal before the critical breakdown of cable insulation, which can provide a reference for judging the severity of terminal spike defects at low temperature.

Low-melting multicharge ionic liquids with [Ln(NO3)5]2- (Ln = Ho-Lu): structural, electrostatic, thermochemical, and fluorescence properties.

A series of green and safe heavy-rare-earth ionic liquids were obtained using a straightforward method. The stable structures of these ionic liquids, characterized by high-coordinating anions, were confirmed by nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, and single crystal X-ray diffraction (XRD). These ionic liquids exhibited wide liquid phase intervals and excellent thermal stability. The bidentate nitrato ligands occupied a sufficient number of coordination sites on the lanthanide ions, resulting in the formation of water-free 10-coordination structures. To explain the anomalous melting points observed in these multi-charged ionic liquids, a combination of experimental data and theoretical studies was employed to investigate the relationship between the electrostatic properties and the melting point. The electrostatic potential density per unit ion surface and volume were proposed and utilized for melting point prediction, demonstrating good linearity. Furthermore, the coordinating spheres of the lanthanide ions in these ionic liquids were devoid of luminescence quenchers such as O-H and N-H groups. Notably, the ionic liquids containing Ho3+, Er3+, and Tm3+ exhibited long lifetime near-infrared (NIR) and blue emissions, respectively. The UV-vis-NIR spectra revealed numerous electronic transitions of the lanthanide ions, which were attributed to their unique optical properties.