initial intensity
Recently Published Documents


TOTAL DOCUMENTS

56
(FIVE YEARS 3)

H-INDEX

13
(FIVE YEARS 0)

2021 ◽  
Author(s):  
Meili Jiang ◽  
Chenhao Li ◽  
B. Qing Tang ◽  
Peng Gao ◽  
Jing Wang ◽  
...  

AbstractAt room temperature, we studied the delayed luminescence characteristic curves of the leaves of Scindapsus in darkroom and continuously irradiate at different wavelengths. The results show that the decay of stimulated emission photons induced by pulsed laser has a typical hyperbolic trend with the delay time, and the goodness of fitted curve can reach 99.9%. The initial photon intensity I (0) and decay time τ are closely related to the environment and physiological activities of plants. In the dark room, it was found that the initial intensity and decay time of the delayed luminescence curve for picked leaves decreased, while the potted leaves remained almost unchanged. The characteristic curve of laser-induced delayed luminescence accurately reflected the process and degree of plant wilting. For continuously irradiated by the laser wavelength of 520 nm and 400 nm, respectively, the change in curve parameters reflects the selective absorption of different light wavelengths. Compare the condition with having light and without, the metabolites of photosynthesis and respiration are different in plants, which leads to greatly changes in decay time. The characteristic curve of laser-induced delayed luminescence can be used as an important parameter to measure the physiological state of plants.


2021 ◽  
Vol 51 (4) ◽  
Author(s):  
Xingchun Chu ◽  
Rongjiang Liu ◽  
Xiang Wang ◽  
Zhongxiang Han ◽  
Yanhui Ni

Finite energy Airy beams (FEAB) generated in laboratory have a short non-diffracting propagation distance (NDPD), which restricts its application in laser communication, laser detection and other fields. Effects of optical Airy transform (OAT) on NDPD of FEAB is analyzed. By comparing the theoretical formulas of the FEAB before and after the OAT, we find that when the transform parameter α of the OAT is larger than zero, the transverse scaling factor of the transformed FEAB is greater than that before the transformation, while the transformed exponential decay factor is smaller than that before the transformation. Using the Huygens–Fresnel diffractive integral, we derive the propagation formula of the transformed FEAB. Initial intensity distribution of FEAB before and after the OAT is compared. Propagation dynamics of the transformed FEAB with different α is numerically simulated and its NDPD is quantitatively evaluated. Results show that: with the increase of α, side lobes of the transformed FEAB increase, its main lobe and side lobes become wider than that before the transformation, and the inclination of the propagation trajectory decreases. When α is greater than half of the transverse scaling factor, the NDPD of the transformed FEAB increases rapidly.


2021 ◽  
Vol 8 (3) ◽  
pp. 560-572
Author(s):  
О. Ye. Kuzmin ◽  
◽  
N. S. Stanasiuk ◽  
D. A. Berdnik ◽  
O. V. Gaiduchok ◽  
...  

A new approach to user behavior modeling based on Game Theory was proposed. It was developed to consider initial intensity, a strategy applied, a profit gained, and resources utilized as inalienable attributes of users' behavior. The approach covers various aspects of users' motivation and rational actions, not only a statistical image of a pool's summary. Additionally, the given model is strongly connected to profit and loss parameters by operating with profit and utilized resources as parts of model inputs. The proposed model can enable efficient modeling aimed to validate an economic result of existing interfaces and assume results of new ones.


2020 ◽  
Vol 312 ◽  
pp. 107-112
Author(s):  
Sergey A. Syubaev ◽  
Aleksey P. Porfirev ◽  
Aleksandr A. Kuchmizhak

Here, we showed formation of chiral nanoprotrusions upon direct laser ablation of bulk crystalline silicon (c-Si) wafer with single femtosecond (fs) pulses having asymmetric donut-shaped intensity profile. Breaking circular symmetry of the irradiating donut-shaped fs-pulse beam was demonstrated to switch the geometry of formed surface nanoprotrusions from regular to chiral, while the chirality of the obtained Si nanostructures was found to promote with a degree of asymmetry of the laser beam. The obtained experimental results explain, for the first time, the formation of previously reported chiral c-Si nanostructures produced via donut-shaped beam ablation in terms of uneven helical flow of laser-melted Si material caused by asymmetry of initial intensity and temperature pattern on laser-irradiated Si surface. Our findings open a pathway towards easy-to-implement inexpensive fabrication of chiral all-dielectric nanostructures for advanced nanophotonic applications.


2020 ◽  
pp. 2551-2561
Author(s):  
Amal F. Jaffar

This study is dedicated to investigate the effects of initial laser intensity on the nonlinear optical properties of the laser dye DQOCI dissolved in methanol with a concentration of 10 -5 M and doped with PMMA film. The properties were studied by using open and closed aperture Z-scan technique, with different levels of initial intensity (I0), excited by continuous diode solid-state laser at a wavelength of 532 nm. Three lenses of different focal lengths were employed to change the radius of the Gaussian laser beam and then change the initial intensity. For I0= 6.83 and 27.304 kWatt/cm2, the Z-scan curves show a saturation of absorption (SA) known as the negative type of nonlinearity, in which the absorption coefficient β 2 decreases and the transmittance increases with increasing the initial laser intensity. With I0 equal to 3.03 KWatt/cm2, the nonlinear absorption changes from SA to RSA, where the transmittances is reduced with the increase of intensity (z0) as analyzed by the theory of free carrier nonlinearities. The closed aperture z-scan shows a pre-focal transmittance minimum (valley) and a post focal transmittance maximum (peak) which reflects the z-scan signature of a positive nonlinearity (self-focusing) due to Kerr effect. Each of nonlinear refractive index (n2), nonlinear absorption coefficient (β 2), and third-order nonlinear optical susceptibility (χ3) are intensity-dependent.


2020 ◽  
Vol 2 (1) ◽  
pp. 17
Author(s):  
Marcelinus AS Adhiwibawa ◽  
Jovine M Kurniawan

In this paper we will discuss the making of the simple photometer instrument to measure the absorbance of natural pigment crude extract. To make simple photometer, cuvette holder was printed using 3D Printing Machine, the development of simple photometer instrument also uses some components such as LED light (633 nm) as the light source, Photodiode-TSL250 as a detector and a variable resistor to set the initial intensity of light source. In this development, Arduino Uno was also used as USB data acquisition device to capture the signal from the instrument. The results of sample measurements between simple photometer instrument and UV-Vis 1800 spectrophotometer showed 98% regression coefficient of determination and simple photometer has a LOD and LOQ absorbance at 0.0267 and 0.0344. Simple photometer instrument was able to show similar response as commercial instrument. Through the development of simple photometer, student can easily understand the working principles of a spectrophotometer in natural pigment analysis that difficult to studied in detailed before.


2019 ◽  
Vol 34 (6) ◽  
pp. 1979-1998 ◽  
Author(s):  
Hsiao-Chung Tsai ◽  
Russell L. Elsberry

Abstract The original 7-day weighted analog intensity Pacific (WAIP) prediction technique is improved by developing a new version for the preformation stage and combining it with the bifurcation version that is especially for the intensification stage and the ending-storm stage WAIP. This combined three-stage WAIP includes a calibrated intensity spread designed to include 68% of the verifying intensities. In this demonstration of the optimum performance of the combined WAIP, the Joint Typhoon Warning Center (JTWC) best tracks, the time to formation (T2F), and ending-storm time are utilized as inputs along with the initial intensity [i.e., either 15 or 20 kt (1 kt ≈ 0.51 m s−1)]. In the new “Before Formation” (defined as 25 kt) stage of the WAIP, the intensity evolution is represented by a square function between the initial intensity and the T2F (25 kt), and very small mean absolute errors (MAEs) and intensity spreads are achieved. In the bifurcation version, correct selections between two cluster WAIP intensity evolutions lead to MAEs that slowly increase to 17 kt at 144 h, and the intensity spreads are relatively small as well. Because the ending-storm time constrains the analog selection in the WAIP, the MAEs begin to decrease after 72 h and are only 10 kt at 156 h. A case study is presented as to how an ensemble storm-track forecast along with the T2F could provide WAIP 7-day intensity predictions beginning in the preformation stage, which indicates the potential for earlier guidance for the JTWC intensity forecasts of western North Pacific tropical cyclones.


Author(s):  
Vasileios Stavropoulos ◽  
Emma Dumble ◽  
Sandra Cokorilo ◽  
Mark D. Griffiths ◽  
Halley M. Pontes

Abstract Internet gaming disorder (IGD) is a rapidly expanding psychopathological manifestation necessitating further research and clinical attention. Although recent research has investigated relationships between user-avatar and excessive gaming, little is known about the interplay between IGD and avatar self-presence and its dimensions (i.e., the physical, emotional, and identity bond developed between the user and the in-game character). The aim of the present pilot study was twofold: (i) to investigate the associations between physical, emotional, and identity aspects of self-presence associate and IGD severity, and (ii) to assess IGD variations longitudinally in relation to the three dimensions of self-presence (i.e., proto-self-presence, core-self-presence, and extended-self-presence). The sample comprised 125 young adults aged between 18 and 29 years who underwent either (i) three offline measurements (1 month apart, over 3 months) or (ii) a cross-sectional online measurement. Regression and latent growth analysis indicated that the initial intensity of the physical, emotional, and identity self-presence aspects associated with IGD severity, but not to its longitudinal change. Overall, young adult gamers may exhibit higher IGD risk and severity when the experience of physical, emotional, and identity bonding with their in-game character is pronounced. The implications surrounding treatment and preventative policy recommendations are further discussed.


2019 ◽  
Vol 22 (5) ◽  
pp. 782-790
Author(s):  
Derek A Pope ◽  
Lindsey Poe ◽  
Jeffrey S Stein ◽  
Brent A Kaplan ◽  
William B DeHart ◽  
...  

Abstract Introduction The experimental tobacco marketplace (ETM) approximates real-world situations by estimating the effects of several, concurrently available products and policies on budgeted purchasing. Although the effects of increasing cigarette price on potentially less harmful substitutability are well documented, the effects of other, nuanced pricing policies remain speculative. This study used the ETM as a tool to assess the effects of two pricing policies, conventional cigarette taxation and e-liquid subsidization, on demand and substitutability. Methods During sampling periods, participants were provided 2-day samples of 24 mg/mL e-liquid, after which ETM purchase sessions occurred. Across two ETM sessions, conventional cigarettes were taxed or e-liquid was subsidized in combination with increasing cigarette price. The other four available products were always price constant and not taxed or subsidized. Results E-liquid functioned as a substitute for conventional cigarettes across all conditions. Increasing cigarette taxation and e-liquid subsidization increased the number of participants for which e-liquid functioned as a substitute. Cigarette taxation decreased cigarette demand, by decreasing demand intensity, and marginally increased the initial intensity of e-liquid substitution, but did not affect the functions’ slopes (substitutability). E-liquid subsidization resulted in large increases in the initial intensity of e-liquid substitution, but did not affect e-liquid substitutability nor cigarette demand. Implications 24 mg/mL e-cigarette e-liquid was the only product to significantly substitute for cigarettes in at least one condition throughout the experiment; it functioned as a significant substitute throughout all four tax and all four subsidy conditions. Increasing cigarette taxes decreased cigarette demand through decreases in demand intensity but did not affect e-cigarette substitution. Increasing e-liquid subsidies increased e-liquid initial intensity of substitution but did not affect cigarette demand. Conclusions This study extended research on the behavioral economics of conventional cigarette demand and e-liquid substitutability in a complex marketplace. The results suggest that the most efficacious method to decrease conventional cigarette purchasing and increase e-liquid purchasing may involve greatly increasing cigarette taxes while also increasing the value of e-liquid through potentially less harmful product subsidization or differential taxation.


2019 ◽  
Vol 67 (1) ◽  
pp. 123-131
Author(s):  
Xabier Artetxe-Gezuraga ◽  
Sara Maldonado-Martín ◽  
Bret G. Freemye ◽  
Jesús Cámara

AbstractThis study assessed gross efficiency (GE) during a single competitive season and determined the relationship between GE and maximum oxygen uptake (V̇O2max) in young elite cyclists (n = 15, 20.1 ± 1.4 yrs, 177.5 ± 5.7 cm, 68.3 ± 6.2 kg, 45.2 ± 7.5 mm of six skinfolds) during a competitive season. Participants completed at two occasions (T1 = April; T2 = July), a progressive bike protocol (initial intensity = 100 W, 35 W increments every 3 min) until volitional exhaustion to assess V̇O2maxand submaximal variables. A single capillary blood sample was drawn from the left earlobe immediately after completion of each exercise load to determine lactate thresholds. Cyclists’ GE was calculated as ([work accomplished/energy expended] x 100). No significant differences were obtained in GE at any workload between T1 and T2 or in the mean GE between T1 (19.3%) and T2 (19.4%) testing (p = 0.93). No significant association was found between mean GE and V̇O2maxat either T1 (r = -0.28, p = 0.30), or T2 (r = -0.27, p = 0.32). GE of young elite cyclists might not vary during the most important phase of the training season and GE was not related to V̇O2max. A lower accumulated volume and intensity of training of these cyclists may account for their lower GE in comparison to older professional cyclists and might not have been enough to foster higher increases of GE in cyclists with lower V̇O2max.


Sign in / Sign up

Export Citation Format

Share Document