Excitation Time Research Articles

Development of a DualEmission Laser-Induced Fluorescence (DELIF) Method for Long-Term Temperature Measurements

The fluorescence intensity of fluorescent dyes typically employed in the dual-emission laser-induced fluorescence (DELIF) method gradually degrades as the excitation time increases, and the degradation rate depends on the type of fluorescent dye used. Therefore, the DELIF method is unsuitable for long-term temperature measurements. In this study, we focused on the fluorescence intensity ratio of a single fluorescent dye at two fluorescence wavelengths and developed a DELIF method for long-term temperature measurements based on this ratio. The fluorescence intensity characteristics of Fluorescein disodium and Rhodamine B, which are typically used in the DELIF method, in the temperature range of 10–60 °C were comprehensively investigated using two high-speed monochrome complementary metal-oxide semiconductor cameras and narrow bandpass filters. Interestingly, the ratio of the fluorescence intensity of each fluorescent dye at the peak emission wavelength of the fluorescence spectrum, λ, to the fluorescence intensity at wavelengths very close to the peak wavelength (λ ± 10 nm) was highly sensitive to temperature variations but not excitation time. Particularly, when Rhodamine B was used, the selection of the fluorescence intensity ratios at a wavelength combination of 589 and 600 nm enabled highly accurate temperature measurements with a temperature resolution of ≤0.042 °C. Moreover, the fluorescence intensity ratio varied negligibly throughout the excitation time of 180 min, with a measurement uncertainty (95% confidence interval) of 0.045 °C at 20 °C. The results demonstrate that the proposed DELIF method enables highly accurate long-term temperature measurements.

Ultrabright and ultrafast afterglow imaging in vivo via nanoparticles made of trianthracene derivatives.

Low sensitivity, photobleaching, high-power excitation and long acquisition times constrain the utility of afterglow luminescence. Here we report the design and imaging performance of nanoparticles made of electron-rich trianthracene derivatives that, on excitation by room light at ultralow power (58 μW cm-2), emit afterglow luminescence at ~500 times those of commonly used organic afterglow nanoparticles. The nanoparticles' ultrabright afterglow allowed for deep-tissue imaging (up to 6 cm), for ultrafast afterglow imaging (at short acquisition times down to 0.01 s) of naturally behaving mice with negligible photobleaching, even after re-excitation for over 15 cycles, and for the accurate visualization of subcutaneous and orthotopic tumours and of plaque in carotid arteries. We also show that an afterglow nanoparticle that is activated only in the presence of granzyme B allowed for the tracking of granzyme-B activity in the context of therapeutic monitoring. The high sensitivity and negligible photobleaching of the organic afterglow nanoparticles offer advantages for real-time in vivo monitoring of physiopathological processes.

Excitation wavelength and time dependent colour tunable room temperature phosphorescence from boron doped carbon nanodots.

Developing metal free room temperature phosphorescence (RTP) materials have received tremendous attention due its potential application in various fields such as sensing, optoelectronics and anticounterfeiting. Herein, we have synthesized an excitation wavelength and time dependent phosphorescent boron doped carbon nanodots (BCNDs) by thermal treatment of ethanolamine and boric acid at 240°C, where boric acid act as both doping and host agents. The obtained BCNDs display blue to orange fluorescence in both aqueous medium and solid state. In addition, the BCNDs display tunable orange-yellow-green phosphorescence in solid state under UV and visible light, lasting upto 10s, visible to naked eye. The boron and nitrogen doping regulates the band gap of the BCNDs, resulting the phosphorescence colour tunability. The average phosphorescence lifetime and quantum yield of BCNDs are found to be 1.27s and 8.61% respectively. Based on the optical properties, the BCNDs are applied as security ink in information encryption and security marking. Hence, this work can promote the development of metal free phosphorescent carbon based materials which may find application in various emerging fields.

Low-frequency stimulation of corpus callosum suppresses epileptiform activity in the cortex through γ-aminobutyric acid type B receptor and slow afterhyperpolarization-mediated reduction in tissue excitability.

Deep brain stimulation, particularly low-frequency stimulation (LFS) targeting fiber tracts, has emerged as a potential therapy for drug-resistant epilepsy (DRE) and for generalized epilepsy, both of which pose significant treatment challenges. LFS diffusely suppresses seizures in the cortex when applied to fiber tracts like the corpus callosum (CC). Nevertheless, the specific processes responsible for suppressing epileptic activity in the cortex induced by LFS remain unclear. This study investigates the mechanisms underlying the antiepileptic effect in the cortex of LFS of the CC in coronal rodent brain slices. An invitro 4-aminopyridine (4-AP) seizure model of cortical seizures was generated. LFS stimulation parameters were optimized to provide the largest antiepileptic effect in the cortex when applied to the CC. Changes to tissue excitability and percent time spent seizing were measured due to LFS in artificial cerebrospinal fluid, 4-AP, and in the presence of various specific and nonspecific γ-aminobutyric acid type B (GABAB) and slow afterhyperpolarization (sAHP) antagonists. LFS significantly suppressed seizure activity in the cortex, with an optimal frequency of 5 Hz (76.5%). Tissue excitability during LFS reduces across a wide range of interstimulus intervals, with a maximum reduction at 200 ms. Notably, the tissue excitability remains depressed at 1000 ms. LFS, in the presence of GABAB antagonists, had diminished seizure reduction (<15%) and failed to reduce tissue excitability in the 50-400-ms range. Tissue excitability measured with paired pulses in the 600-1000-ms range was depressed in the presence of GABAB antagonists, suggesting a different antiepileptic mechanism was active. Upon administering sAHP antagonists, seizure reduction was once again diminished (<15%). Upon administration of both sAHP and GABAB antagonists, LFS failed to provide any meaningful seizure reduction (<5%). LFS of the CC provides an antiepileptic effect in the cortex with well-understood mechanisms and could be an alternative to surgical intervention for patients suffering from DRE.

A coupled displacement-pressure model for elastic waves induce fluid flow in mature sandstone reservoirs

Elastic (seismic) wave stimulation is considered one of the unconventional enhanced oil recovery (EOR) methods. Increasing water quantity in the high permeability layer of a mature oil reservoir is highly challenging and can significantly decrease the ultimate recovery due to the reservoir heterogeneity. Using seismic waves can be considered low-cost, environmentally friendly, and illuminates the entire reservoir size compared to conventional EOR methods. A numerical model is developed by extending the Quintal approach for seismic attenuation due to wave-induced fluid flow (WIFF) to incorporate capillary pressure in partially saturated porous media and shift undrained boundary conditions to exclude external flow stress for drained boundary conditions. Therefore, the fluid distribution due to the capillary effect makes the developed finite element method (FEM) u-p model more widely applicable for oil recovery in mature reservoirs. A two-layer partially saturated media was subjected to compressive seismic stress at low frequency (3 Hz). The results indicated that the vertical displacement gradients of the bottom and upper layers decline with excitation time for both fully and partially saturated media. On the other hand, partially saturated pore pressure gradients of both the upper and bottom layers have higher amplitudes with excitation time than fully saturated pore pressure gradients due to the influence of capillar pressure. The cumulative crossflow oil volume for 180 days of continuous stimulation was 1176 bbl, 1032 bbl, and 648 bbl in low permeability layers: 200 md, 100 md, and 50 md, respectively. Therefore, the developed model has the potential for field-scale EOR applications. The study also suggests coupling elastic EOR with CO2 flooding to recover more oil due to increasing fluid mobility and relative permeability to oil in low-permeability reservoirs or tight formations.

Including Photoexcitation Explicitly in Trajectory-Based Nonadiabatic Dynamics at No Cost.

Over the last decades, theoretical photochemistry has produced multiple techniques to simulate the nonadiabatic dynamics of molecules. Surprisingly, much less effort has been devoted to adequately describing the first step of a photochemical or photophysical process: photoexcitation. Here, we propose a formalism to include the effect of a laser pulse in trajectory-based nonadiabatic dynamics at the level of the initial conditions, with no additional cost. The promoted density approach (PDA) decouples the excitation from the nonadiabatic dynamics by defining a new set of initial conditions, which include an excitation time. PDA with surface hopping leads to nonadiabatic dynamics simulations in excellent agreement with quantum dynamics using an explicit laser pulse and highlights the strong impact of a laser pulse on the resulting photodynamics and the limits of the (sudden) vertical excitation. Combining PDA with trajectory-based nonadiabatic methods is possible for any arbitrary-sized molecules using a code provided in this work.

Lamb Wave Probabilistic Damage Identification Based on the Exchanging-Element Time-Reversal Method.

The commonly used baseline-free Lamb wave damage identification methods often require a large amount of sensor data to eliminate the dependence on baseline signals. To improve the efficiency of damage localization, this paper proposes a new Lamb wave damage location method, namely the probabilistic exchanging-element time-reversal method (PEX-TRM), which is based on the exchanging-element time-reversal method (EX-TRM) and the probabilistic damage identification method. In this method, the influence of the damage wave packet migration on the correlation coefficient between the reconstructed signals of each sensing path and the initial excitation signal is analyzed, and the structure is divided into multiple regional units corresponding to the damage to locate damage. In addition, the influence of the number of sensing paths on the location accuracy is also analyzed. A method of damage probability imaging based on structural symmetry is proposed to enhance location accuracy in the case of sparse sensing paths. The experimental and simulation results verify that the method can achieve damage location with fewer excitation times. Moreover, this method can avoid the problem that the damage wave packet is difficult to extract, improve the efficiency of damage location, and promote the engineering application of the Lamb wave damage location method.

Synthesis and investigation of the optical characteristics of RE3+ activated Ca2Li2Si2O7 (Rare earth = Eu, Tb) phosphor for W-LED application

Novel Eu3+ and Tb3+ ions-doped Ca2Li2Si2O7 luminescent materials were prepared by a low-temperature solid-state reaction technique for LED application. The electronic transitions of 5D0 → 7F2 (Eu3+) and 5D4 → 7F5 (Tb3+) have caused the luminescent material to exhibit strong luminosity in 613 nm (red) and 545 nm (green), respectively. Fourier transform infrared (FT-IR) spectra were applied for the identification of functional groups, and powder X-ray diffraction (XRD) was used for structural analysis. Morphological data was gathered using scanning electron microscopy (SEM). Its color was also determined by calculating the CIE coordinates. The excitation, PL properties, and luminescence decay time of the emission transitions of Eu3+ (5D0 → 7F2) and Tb3+ (5D4 → 7F5) were measured in order to analyze luminosity spectra.

Incorporating multi-source uncertainties in fast building wall thermal resistance estimation through physics-based and multi-fidelity statistical learning models

Meta-modeling and Bayesian inversion technique are proposed for fast and accurate in-situ estimation of the total thermal resistance (RTot) of walls using non-intrusive wall instrumentation. Various sources of uncertainties are taken into account to provide an enhanced credible interval for the thermal resistance estimate. In the considered protocol, a small zone of the internal surface of the wall is excited by a prototype to get faster in situ estimation and to limit the influence of external weather conditions. To be independent of the heat transfer coefficients and of the misknown layer thicknesses, which are difficult to estimate, we use herein the measurements of internal and external surface temperatures as boundary conditions in a thermal direct problem reformulated. A meta-model of the thermal model is created based on a statistical multi-fidelity approach with two levels of fidelity, Resistance-Capacitance (RC) and 1D models, to achieve the Bayesian estimation of the total thermal resistance in a reasonable computation time. The RTot estimation method is applied to realistic internal insulated walls (IIW), from poorly to highly insulated, under different weather conditions. Several numerical tests are carried out and credible intervals are provided to study the importance of the wall initial condition, the excitation time and the instrumentation. Finally, an experimental application is conducted using real measurements on an internal insulated wall (IIW) in Nancy (France). The obtained experimental results show that, in a short excitation time (10h) with a reduced instrumentation, the proposed method accurately estimates the minimum wall thermal resistance. For a standard wall of about 4 m2.K/W, a relevant estimate of RTot with a relative deviation less than 10% can be achieved by using a polynomial initial temperature profile proposed in this study, sufficient measurements and an excitation time of 3 days. This study thus offers prospects for improved energy assessment of buildings before and after renovation.

Multi-metric luminescence properties of Sm3+/Er3+ doped Ca2Ga2GeO7: Excitation, time, and temperature

In this study, we explored the potential of Sm3+/Er3+-doped Ca2Ga2GeO7 (CGGO:RE, RE = Sm/Er) as an innovative phosphor, harnessing its versatile photoluminescence properties that depend on various factors, including the excitation wavelength, time, and temperature. Our CGGO:Sm and CGGO:Er samples exhibited promising green and red emissions under UV/Near-UV (NUV) excitation and chromatic changes depending on the excitation wavelength. These color-changing characteristics hold promise for applications in the fields of NUVLEDs and optoelectronics. Furthermore, we observed a significant change in the emission hues of CGGO:Sm as a function of time. We suggest that this moment-color change can be utilized in optical chronometry. Additionally, outstanding thermometric behavior was observed in the upconversion spectra of CGGO:Er. Interestingly, the temperature-dependent behaviors of the luminescent peaks were inconsistent, increasing, constant, or decreasing, which successfully enabled remarkable thermometric performance. Our findings on the multi-metric luminescence properties of CGGO:RE demonstrated the potential of this material to be applied in various fields and highlight its versatility.

Efficient Method for Enhancing Reverse-Time Migration Images Using Vertical Seismic Profiling Data

Vertical seismic profiling has garnered widespread attention in the industry as a supplement to seismic exploration due to its higher data quality compared to surface seismic data. However, its unique observation system in which geophones are only distributed within observation wells results in uneven coverage of subsurface structures. This can lead to significant noise when directly applying conventional reverse-time migration techniques used in surface seismic imaging. This study addresses the issue of noise suppression in reverse-time migration imaging associated with walk-away vertical seismic profiling and presents two main innovations. First, a common-receiver reverse-time migration imaging method is proposed, which uses the observation signals as excitation signals for the corresponding shots after reverse-time processing. Second, an excitation-time-constrained cross-correlation imaging condition is introduced to eliminate non-contributing portions of the wavefield, thereby modifying the traditional cross-correlation imaging condition to include an excitation time constraint. The combination of these methods enhances imaging quality by effectively suppressing noise, as demonstrated through theoretical analysis and numerical simulations with synthetic models.

Charge Transfer in He+ - He → He(1s4l, l ≥ 2) - He+ Collisions in Intermediate Energy Range.

The anticrossing spectra of the helium line λ1s4l D3,F-1s2p P3=447.2 nm emitted after electron capture by He+ ions in He+-He collisions were measured for projectile energies of 10-29 keV. Furthermore, considering the excited states' time evolution, the theoretical intensity functions were calculated. The electric field and density distributions of the target He atoms in the collision volume were taken into account, and by fitting the theoretical intensities to the measured ones, the post-collisional states of the charge-transferred He atoms were determined. The results indicate that for the intermediate projectile energy range, the electronic charge distributions were asymmetric, but the electric dipole moments did not change, as in the case of the target atoms excited directly in the collisions. This result shows that the Paul trap mechanism may play an important role in the charge transfer excitation in this energy range.

A large-aperture, high-power ultrawideband radiation system with beam broadening capacity.

Due to the limited maximum output power of the pulsers based on avalanche transistors, high-power ultrawideband (UWB) radiation systems usually synthesize plenty of modules simultaneously to achieve a high peak effective potential (rEp). However, this would lead to an increased aperture size as well as a narrower beam, which would limit their applications in intentional electromagnetic interference fields. In this paper, a high-power UWB radiation system with beam broadening capacity is developed. To achieve beam broadening in the time domain, a power-law time delay distribution method is proposed and studied by simulation, and then the relative excitation time delays of the modules are optimized to achieve higher rEp and avoid beam splitting in the beam broadening mode. In order to avoid false triggering of the pulser elements when implementing the beam broadening, the mutual coupling effect in the system is analyzed and suppressed by employing onboard high-pass filters, since the mutual coupling effect is much more severe in the low-frequency range. Finally, a radiation system with 36 modules is developed. Measuring results indicate that in the high-rEp mode, the developed system could achieve a maximum effective potential rEp of 313.6kV and a maximum pulse-repetition-rate of 20kHz. In the beam broadening mode, its half-peak-power beam width in the H-plane is broadened from the original value of 3.9° to 7.9°, with a maximum rEp of 272.9kV. The polarization direction of the system could be flexibly adjusted by a built-in motor.

Garbhopaghatakara Bhavas: A Conceptual Study

Abstract: न èğी समम ्र×नम ्There aren't any women who resemble jewels. Because they can bear children, women are extremely valuable. The reproductive stage is the most crucial of the various stages in a woman's life. Being a mother is an amazing dream. The most exciting and difficult time in a woman's life is when she becomes pregnant in order to have healthy children without experiencing any problems before, during, or after pregnancy. Pregnant women should follow the detailed instructions provided by acharyas such as Garbhini paricharya, Patya-apatya, Douhruda apamana, etc. to prevent difficulties and have healthy offspring. Pregnancy is not the time to engage in garbhopaghatakara bhavas. These are nothing but the daily activities and dietetics if followed by pregnant women lead to complications in the fetus like Garbha srava, Garbha vyapads, etc. Due to certain unknown errors of nature and lifestyle of pregnant women, it can take a bad U-turn in their life. Acharyas have explained in brief about Yonivyapad and acharya Kashyapa mentions Jathaharinis, relating to the abortion / fetal loss taking place in different stages of pregnancy. Critical analysis of these Garbhopaghatakara bhavas can guide towards the formulation of a better preventive plan for Garbha vyapads mainly abortions.

PENGARUH TERAPI MUSIK TERHADAP KECEMASAN IBU HAMIL DI DESA SIGULANG KECAMATAN PADANGSIDIMPUAN TENGGARA

Pregnancy is an exciting time and is awaited by mothers and families. All mothers want their pregnancies and deliveries to go safely, smoothly, and normally. However, pregnancy is also a time of excitement and worry. Pregnancy can be a period of crisis in which the mother often feels worried or afraid of the pain and physical dangers that arise during childbirth. This causes bleeding in pregnant women during childbirth. The purpose of this study was to determine the effect of music therapy on reducing anxiety of pregnant women in Sigulang Village, Padangsidimpuan Tenggara District, health. The research used was quasi-experimental research (pseudo-experiment) using the Prettest posttest only research design. The research site is in Sigulang Village, Padangsidimpuan Tenggara District. The study population was 20 pregnant women, the study sample was 20 people. Data analysis using univariate analysis and bivariate analysis. The results showed that there was a decrease in anxiety of pregnant women and the average anxiety score of pregnant women before religious music therapy was 35.33 and after religious music therapy there was a decrease in anxiety with an average of 25.83. The p-value is 0.001, meaning that there is an effect of music therapy on reducing anxiety. The implication of this study is that the provision of religious music therapy can reduce anxiety in pregnant women when facing childbirth.

Exciton migration in two-dimensional materials

Excitons play an essential role in the optical response of two-dimensional materials. These are bound states showing up in the band gaps of many-body systems and are conceived as quasiparticles formed by an electron and a hole. By performing real-time simulations in hBN, we show that an ultrashort (few-fs) UV pulse can produce a coherent superposition of excitonic states that induces an oscillatory motion of electrons and holes between different valleys in reciprocal space, leading to a sizeable exciton migration in real space. We also show that an ultrafast spectroscopy scheme based on the absorption of an attosecond pulse in combination with the UV pulse can be used to read out the laser-induced coherences, hence to extract the characteristic time for exciton migration. This work opens the door towards ultrafast electronics and valleytronics adding time as a control knob and exploiting electron coherence at the early times of excitation.

Estimation of Frequencies and Splitting of &lt;sub&gt;2&lt;/sub&gt;S&lt;sub&gt;1&lt;/sub&gt; and &lt;sub&gt;3&lt;/sub&gt;S&lt;sub&gt;1&lt;/sub&gt; Modes from the IGETS Superconducting Gravimeter Network Data after the 2013 Sea of Okhotsk Earthquake

For the first time, the 2S1 and 3S1 modes of the Earth’s free oscillations following the largest deep-focus earthquake in the Sea of Okhotsk on May 24, 2013, have been analyzed using the maximum likelihood method. Data from 14 superconducting gravimeters of the IGETS network deployed in the central part of Europe were used for the analysis. Estimates of the time of mode excitation after the earthquake origin time, degenerate frequencies, and mode splitting parameters are obtained.

Non-drug therapies for patients with vibration disease associated with exposure to local vibration

Non-drug methods include acupuncture, the most effective way to regulate the body's energy system. Pulsed magnetic stimulation (PMS) is based on the application of the principles of electromagnetic induction, causes hyperpolarization or depolarization of nerve cells. The methods are practically not used in the clinic of occupational diseases, and their effectiveness in the treatment of vibration disease (VD) has not been established. The study aims to evaluate changes in the central nervous system and peripheral nerves, as well as in the psychological status of patients with vibration disease after sessions of acupuncture and pulsed magnetic stimulation. Using the acupuncture method, 24 male patients were treated with a diagnosis of VD associated with exposure to local vibration (average age 49.9±3.8 years, average length of service — 19.4±4.3 years), PMS — 24 people with a diagnosis of VD associated with exposure to local vibration (average age 48.8±3.4 years, average length of service — 18.1±3.4 years). The treatment methods performed made it possible to improve the quality of therapy, which was confirmed by a positive change in the indicators of visual and somatosensory evoked potentials, data from electroneuromyographic studies, vibration sensitivity and algesimetry, the state of the mnestic and attentional spheres of activity improved. The use of the acupuncture method allowed to improve the indicators of bioelectric activity of the brain: the amplitude of the peak N1 of visual evoked potentials increased (from 3.2 to 6.7 MV, p&lt;0.05), the latency of the peak P200 decreased from 178.0 to 142.5 ms, p&lt;0.05. The threshold of pain sensitivity on the zygomatic bone, on the phalanx of the 2nd finger of the hand and on the protruding part of the inner ankle decreased by 63, 125 and 250 Hz, p&lt;0.05. Vibration sensitivity improved (on the ulnar process, phalanx of 2 fingers of the hand, p&lt;0.01, on the tubercle of the tibia, p&lt;0.05). Magnetic stimulation contributed to the improvement of cerebral changes in the treated patients — the latency of auditory evoked potentials decreased (p&lt;0.03 for peak P1 and p&lt;0.05 for peak P2), the amplitude of visual evoked potentials increased (p&lt;0.05), the bioelectric activity of the occipital lobes of the brain increased. The duration of the afferent excitation wave at the level of the cervical region (latency N11 and N13, p&lt;0.05) and thalamic structures (latency P25, p&lt;0.05) increased. Non-drug therapy allowed to restore the time of excitation by the motor component of axons in patients on the upper extremities during acupuncture, on the upper and lower extremities during treatment with magnetic stimulation (p&lt;0.05), improved indicators characterizing the mnestic-attentional and psychoemotional spheres of the treated. Ethics. Conclusion of the MEС of the Federal State Budgetary Scientific Institution "East Siberian Institute of Medical and Environmental Research" No. 32 dated 09/10/2019.

Analysis of Dynamic Systems Through Artificial Neural Networks

Parameter identification techniques for linear and nonlinear dynamic systems currently show a clear orientation toward black box models, with Artificial Neural Networks occupying a prominent place there. This paper presents a procedure for identifying linear dynamic systems parameters in two stages: in the first, a regressive model is fitted from the excitation and response time records, and in the second, its parameters are identified (matrixes of stiffness and damping) and dynamic characteristics (vibration frequencies and modes) based on the previous model. Artificial Neural Networks of the Adaline type and multilayer Perceptions are used for the first stage. The second stage is fully formulated through matrix algebra, which facilitates its systematic implementation and makes it independent of the complexity or dimension of the studied system. The proposed procedure is intended to operate from experimental records, so special attention is paid to the sensitivity of the results to the data interval and noise in the input signals. For the latter, various noise levels were incorporated into the correct responses obtained under ideal conditions, which respond to Gaussian distribution functions with a null mean and specified standard deviation. The proposed procedure justification, the results with the regressive models, and a study of the sensitivity of the results to the variation in the available data quality are presented.

A Novel Low-Frequency Electromagnetic Active Inertial Sensor for Drug Detection.

The purpose of this paper is to demonstrate a new discovery regarding the interaction between materials and very low radio frequencies. Specifically, we observed a feedback response on an inertia active sensor when specific frequencies (around 2-4 kHz) are used to irradiate targeted pharmaceutical samples like aspirin or paracetamol drugs. The characteristics of this phenomenon, such as excitation and relaxation time, the relation between deceleration and a material's quantity, and signal amplitude, are presented and analyzed. Although the underlying physics of this phenomenon is not yet known, we have shown that it has potential applications in remote identification of compounds, detection, and location sensing, as well as identifying substances that exist in plants without the need for any processing. This method is fast, accurate, low-cost, non-destructive, and non-invasive, making it a valuable area for further research that could yield spectacular results in the future.