Fast Decay Research Articles

Determination of lutetium density in LYSO crystals: methodology and PET detector applications

Objective. Lutetium yttrium oxyorthosilicate (LYSO) scintillation crystals are used in positron emission tomography (PET) due to their high gamma attenuation, fair energy resolution, and fast scintillation decay time. The enduring presence of the 176Lu isotope, characterized by a half-life of 37.9 billion years, imparts a consistent radiation background (BG) profile that depends on the geometry and composition attributes of the LYSO crystals. Approach. In this work, we proposed a methodology for estimating the composition of LYSO crystals in cases where the exact Lutetium composition remains unknown. The connection between BG spectrum intensity and intrinsic radioactivity enables precise estimation of Lutetium density in LYSO crystal samples. This methodology was initially applied to a well-characterized LYSO crystal sample, yielding results closely aligned with the known composition. The composition estimation approach was extended to several samples of undisclosed LYSO crystals, encompassing single crystal and crystal array configurations. Furthermore, we model the background spectrum observed in the LYSO-based detector and validate the observed spectra via simulations. Main results. The estimated Lutetium composition exhibited adequate consistency across different samples of the same LYSO material, with variations of less than 1%. The result of the proposed approach coupled with the simulation successfully models the background radiation spectra in various LYSO-based detector geometries. Significance. The implications of this work extend to the predictive assessment of system behaviors and the autonomous configuration parameters governing LYSO-based detectors.

Mg/Ta dual-site doping of high-nickel layered cathode material LiNi0.9Co0.1O2 for extended cycling and thermal stability

Due to its high specific capacity and low cost, high-nickel layered oxide LiNi0.9Co0.1O2 has found promising application as the cathode materials for lithium-ion batteries. However, the crystallographic instability induced by Li+/Ni2+ anti-site exchange, the interfacial parasitic reactions and the microcracking caused by internal stress jointly contribute to the mechano-chemical failure of LiNi0.9Co0.1O2, leading to its fast capacity decay and high thermal stability concern. In this regard, a Mg/Ta dual-site doping strategy was proposed for LiNi0.9Co0.1O2, for which Mg2+ was doped in situ during the synthesis of cathode precursor, while Ta5+ ions were incorporated after the precursor synthesis. This novel synthesis approach leads to unique dual-site occupations of Mg2+ and Ta5+ in the 3a and 3b crystallographic sites respectively. The Mg2+ ions residing in 3a site can function as pillar ions by preventing the Li+/Ni2+ anti-site exchange and inhibiting layered to rock-salt phase transition. The Ta5+ ions occupying 3b site not only leads to the expanded lithium layer spacing but also creates interfacial protection and well-ordered microstructure in LiNi0.9Co0.1O2. Consequently, the dual-site-doped LiNi0.9Co0.1O2 outperforms the pristine and single-site-doped samples. For instance, its full cell shows a greatly enhanced cycling stability from 57.3 % to 90.5 % after 300 cycles at 1C/1C and well improved thermal stability from 205.2 °C to 225.6 °C, compared to the pristine sample. This Mg/Ta dual-site doping strategy provides a facile and practical way to improve the electrochemical and thermal performances of high-nickel layered cathode material LiNi0.9Co0.1O2.

Comparative study of the near-infrared detection of PbSe fabricated using a sputter deposition method

Near-infrared (NIR) light is used in nondestructive spectroscopies to analyze various compounds in several applications. A PbSe nanocrystal film used in NIR detectors is fabricated using a magnetron sputtering process. The PbSe NIR detectors can be fabricated at a low cost and can operate at ambient temperatures. In this study, the surface morphology and chemical and crystal states of PbSe and its NIR detection performance are investigated and compared with existing reports in the literature. The PbSe film grown by sputtering exhibits nano- and columnar crystal structures, predominantly halite-like (100) face-centered cubic structures. The PbSe film contains PbO and SeO2 and exhibits dual-absorption band-to-band transitions at 0.43 and 0.52 eV. The sputtered PbSe film is used to fabricate an NIR photodetector with a metal-semiconductor-metal structure. The detector shows fast rise and decay times of 0.14 and 0.12 s, respectively, and responsivity of approximately 0.01 A/W under infrared illumination. Based on this study, a low-cost PbSe NIR detector that can operate at room temperature is developed for early fire detection.

First-principles calculations to investigate the structural stability, electronic and mechanical properties of CuGa2 and Cu9Ga4

This paper aims to evaluate the service reliability of intermetallic compounds (IMCs) in Cu-Ga joints. It accomplished this by calculating the thermodynamic and mechanical properties of CuGa2 and Cu9Ga4, which are common IMCs in Cu-Ga low temperature interface reaction, based on the first-principles calculation. According to the calculation results of enthalpy of formation and binding energy, both CuGa2 and Cu9Ga4 are thermodynamically stable, and Cu9Ga4 exhibits superior thermodynamic stability compared to CuGa2. The mechanical properties of Cu9Ga4 are better than CuGa2, with larger bulk modulus, shear modulus and Young's modulus. By comparing the elastic modulus with that of IMCs of Cu-Sn system, Cu9Ga4 shows larger elastic modulus than η′-Cu6Sn5 and smaller than Cu3Sn. In addition, Cu9Ga4 exhibits excellent toughness. By fitting the thermal expansion coefficients of Cu, CuGa2 and Cu9Ga4, the result shows that the thermal expansion coefficients of Cu and Cu9Ga4 are better matched. Additionally, the rapid volume expansion of CuGa2 weakens the interaction force between its atoms, resulting in a faster decay of its bulk modulus. The prediction of the mechanical properties of Cu-Ga compounds provides a deeper understanding of their properties and is important for the understanding of the feasibility of low-temperature brazing of Cu-Ga soldering systems.

Mechanical Damage Caused by Compression and Its Effects on Storage Quality of Mandarin.

Mandarin is vulnerable to a range of external loads during processing and shipping, which can cause interior mechanical damage that can happen right away or over time and cause serious rotting when kept in storage. In this study, mandarin was treated to a certain quantity of compression load that did not result in a noticeable rupture of the peel. The interior pulp structure of mandarin was examined for damage prior to peel damage using CT scanning and image reconstruction. An image segmentation method based on mask processing was then used to calculate the pulp damage rate. We examined the variations in physiological activities and internal components between the test group that underwent compression load and the control group that did not undergo this type of stress during storage. The aim was to investigate the factors that contributed to the faster decay of mandarin following mechanical damage. Regression analysis was also used to establish a quantifiable relationship between the amount of compression deformation and the rates of damage and decay of mandarin during storage. The findings demonstrated that mandarin pulp exhibited visible mechanical damage when compression deformation exceeded 8 mm. This led to the disruption of physiological processes like respiration and polysaccharide breakdown, which in turn decreased the hardness of the fruit and sped up its rotting. This study identifies the critical range of compression deformation that leads to the beginning of pulp damage in mandarins. Additionally, it clarifies the quality deterioration mechanism of mandarins that have been subjected to compression damage during the storage period. Therefore, in practical production, various methods of picking, sorting, and collecting mandarins can be optimized to control the amount of compression deformation within a suitable range. This will reduce the probability of pulp damage. According to the study's conclusions, storage conditions can be optimized to regulate the physiological activities of mandarins in a targeted manner. This can minimize the probability of fruit decay and reduce economic losses.

Tuning the Interface Stability of Nickel-Rich NCM Cathode Against Aggressive Structural Collapse via the Synergistic Effect of Additives.

Nickel-rich layered oxides are envisaged as one of the most promising alternative cathode materials for lithium-ion batteries, considering their capabilities to achieve ultrahigh energy density at an affordable cost. Nonetheless, with increasing Ni content in the cathodes comes a severe extent of Ni4+ redox side reactions on the interface, leading to fast capacity decay and structural stability fading over extended cycles. Herein, dual additives of bis(vinylsulfonyl)methane (BVM) and lithium difluorophosphate (LiDFP) are adopted to synergistically generate the F-, P-, and S-rich passivation layer on the cathode, and the Ni4+ activity and dissolution at high voltage are restricted. The sulfur-rich layer formed by the polymerization of BVM, combined with the Li3PO4 and LiF phases derived from LiDFP, alleviates the problems of increased impedance, cracks, and an irreversible H2-H3 phase transition. Consequently, the Ni-rich LiNixM1-xO2 (x > 0.95) button half-cell cycled in LiDFP + BVM electrolyte exhibits a significant discharging capacity of 181.4 mAh g-1 at 1 C (1 C = 200 mA g-1) with retention of 83.7% after 100 cycles, surpassing the performance of the commercial electrolyte (160.7 mAh g-1) with retention of 53.3%. Remarkably, the NCM95||graphite pouch cell exhibits a remarkable capacity retention of 95.5% after 200 cycles. This work inspires the rational design of electrolyte additives for ultrahigh-energy batteries with nickel-rich layered oxide cathodes.

High‐Temperature X‐Ray Imaging with Transparent Ceramics Scintillators

AbstractScintillators with high spatial‐resolution and high‐stability are highly desirable for X‐ray imaging applications at unpredictable environments. To challenge state‐of‐the‐art technology, it is necessary to design high thermal stable scintillators with high‐resolution and high light yield. In this work, the zero‐thermal‐quenching Lu3Al5O12:Ce3+ (LuAG: Ce3+) transparent ceramics (TCs) is synthesized with high optical transparency. The thermoluminescence (TL) curves of the as‐obtained TCs demonstrate that the formation of the oxygen vacancies, acting as the trapping centers, can capture the carriers and then contribute to the enhancement of its thermals stability via the thermal compensation effect. The exceptional thermal‐stability of the TCs scintillator endows the monitoring of the dynamic changes of the internal structure of the objective samples without any ghosting effects during heating. In addition, given the ultra‐high uniform, transparency, and fast light decay of the TCs scintillator, the excellent spatial resolution (≈112 lp mm−1) of the X‐ray microscopic imaging is realized. These results undeniably demonstrate that the as‐obtained LuAG: Ce3+ TCs have great prospects for advancement in X‐ray detectors.

Global well-posedness and large time behavior for the inviscid Oldroyd-B model

In this paper, we consider the 3-dimensional incompressible inviscid Oldroyd-B model. Firstly, we establish the global existence of the solutions for the inviscid Oldroyd-B model with different coupling coefficient k>0. Then, we show the connection between the solution with the parameter k that is the reciprocal of Weissenberg number. On one hand, we prove that the solutions (u,τ) depend continuously on the parameter k>0, though (u,τ) corresponds to different decays rate for different k. On the other hand, when k→0 in large time, we prove that there is a gap between the L2 norm of solution uk(t,x) to the model of parameter k>0 with the L2 norm of solution u0(t,x) to the model of parameter k=0. In a word, we prove that the larger positive k induces the faster decay rate of the solution, but k cannot go to zero, or the dissipation will vanish instantly.

Toward deeper ultraviolet detection: Atomic layer deposited amorphous AlGaOx thin film detector with its tunable optical properties and opto-electronic responses

Employing atomic layer deposition, AlGaOx films with varying Al concentrations (highest to 44% at.) were meticulously synthesized. Comprehensive characterization encompassing chemical composition, elemental depth distribution, structural clarity, and interface delineation unequivocally attested to the superior quality of the films. Optical properties were rigorously assessed using transmittance spectra and spectroscopic ellipsometry (SE), and optical constants across a broad spectral range (200–1000 nm) were determined through SE fitting. A consistent blue-shift in the absorption edge, observed in both the transmittance spectra and extinction coefficient, is attributed to the incorporation of aluminum. Detailed exploration via X-ray photoelectron spectroscopy fine scans of O 1s energy loss spectra and valence band analysis revealed that the evolution of the conduction band is instrumental in modulating the bandgap. To ascertain the viability for deep ultraviolet light detection, photodetectors based on AlGaOx were fabricated. Blue shifts in both photocurrent and response peak wavelength correlated with increasing Al content. In specific occasions, the AlGaOx-based detector has a responsibility of 0.05 A/W and 7×1013 detectivity of Jones. Remarkably, the detector demonstrates commendable on/off capability, characterized by fast rise and decay times of 0.26 s and 0.17 s, respectively. This study extensively examined the chemical, structural, and optical properties of amorphous AlGaOx films, alongside the optoelectronic capabilities of AlGaOx-based devices. Our research presented a viable strategy for enhanced deep ultraviolet detection, showcasing a successful implementation of amorphous bandgap engineering. This endeavor holds promise for future advancements in UV-detector development.

Measurement of nanocomposite scintillators by terahertz time domain spectroscopy.

Nanocomposite scintillators are expected to combine the advantages of inorganic and plastic scintillators, such as high detection efficiency, high light yield, fast decay time, low cost, and ease of processing. They are currently the forefront and hot field of scintillator research. In this study, a non-destructive method was developed for measuring the content of inorganic components in nanocomposite scintillators by terahertz time-domain spectroscopy. The complex refractive index of B a F 2 nanocomposite scintillators with different mass contents was measured in the terahertz band. As the mass content of B a F 2 nanoparticles increases, the refractive index and extinction coefficient of B a F 2 nanocomposite scintillators also gradually increase in the terahertz band. By combining the effective medium theory, the expected mass content was obtained, proving the feasibility of this measuring method.

Assessing the nucleic acid decay of human wastewater markers and enteric viruses in estuarine waters in Sydney, Australia

This research investigated the in-situ decay rates of four human wastewater-associated markers (Bacteroides HF183 (HF183), Lachnospiraceae Lachno3 (Lachno3), cross-assembling phage (crAssphage), pepper mild mottle virus (PMMoV) and three enteric viruses (human adenovirus 40/41 (HAdV 40/41), enterovirus (EV) and human norovirus GII (HNoV GII) in two estuarine water environments (Davidson Park (DP) and Hen and Chicken Bay (HCB) in temperate Sydney, NSW, Australia, employing qPCR and RT-qPCR assays. The study also aimed to compare decay rates observed in mesocosms with previously published laboratory microcosms, providing insights into the persistence of markers and viruses in estuarine environments. Results indicated varying decay rates between DP and HCB mesocosms, with HF183 exhibiting relatively faster decay rates compared to other markers and enteric viruses in sunlight and dark mesocosms. In DP mesocosms, HF183 decayed the fastest, contrasting with PMMoV, which exhibited the slowest. Sunlight induced higher decay rates for all markers and viruses in DP mesocosms. In HCB sunlight mesocosms, HF183 nucleic acid decayed most rapidly compared to other markers and enteric viruses. In dark mesocosms, crAssphage showed the fastest decay, while PMMoV decayed at the slowest rate in both sunlight and dark mesocosms. Comparisons with laboratory microcosms revealed faster decay of markers and enteric viruses in laboratory microcosms than the mesocosms, except for crAssphage and HAdV 40/41 in dark, and PMMoV in sunlight mesocosms. The study concludes that decay rates of markers and enteric viruses vary between estuarine mesocosms, emphasizing the impact of sunlight exposure, which was potentially influenced by the elevated turbidity at HCB estuarine waters. The generated decay rates contribute valuable insights for establishing site-specific risk-based thresholds of human wastewater-associated markers.

Unveiling Electric Field Induced Ultrafast Charge Transfer Dynamics and Photoresponse Enhancement in Gold‐Interlayered Bi2Se3

AbstractIn the realm of optoelectronic applications, the incorporation of a metal interlayer between layers of a topological material holds significant potential. The interlayer introduces benefits such as improved charge transfer efficiency, tunable band alignment, plasmonics effect, and enhanced light‐matter interactions, paving the way for more efficient and versatile optoelectronic devices. This work explores the incorporation of gold between Bi2Se3, resulting in an enhancement in the response time of photoresponse of interlayered systems (Bi2Se3‐Au‐Bi2Se3). The introduction of a gold interlayer between Bi2Se3 significantly influences the overlayer structure, crystallinity, crystallite size, and even phonon behavior. Moreover, the responsivity of the interlayered device at a bias (2 V) is found to have high responsivity with fast response and decay time (τr = 0.1 ms, and τd = 24 ms of interlayered systems) as compared to intrinsic Bi2Se3(τr = 0.6 ms, and τd = 28 ms). This change is attributed to the bandgap alteration of the Bi2Se3/Au interface, which is monitored through transient spectroscopy performed at different electric biases. This study suggests that incorporating a gold interlayer holds potential benefits for various optoelectronic applications.

WIMP constraints from black hole low-mass X-ray binaries

The abnormally fast orbital decay observed in the black hole (BH) Low-Mass X-ray binaries (BH-LMXB) A0620-00 and XTE J1118+480 can be explained by the dynamical friction between Dark Matter (DM) and the companion star orbiting around the low-mass BH (≃ a few M ⊙) of the system. In this case the value of the index γ sp of the DM spike surrounding the BH can be pinned down with an accuracy of ≃ a few percent, way better than that for much bigger systems such as the super massive BHs (SMBHs) in the Galactic Center or in M87. We have used data from XTE J1118+480 to put bounds on the WIMP annihilation cross section times velocity ⟨σv⟩, assuming that DM annihilation is driven by the χχ → bb̅ annihilation channel and that it proceeds in s-wave. The bounds are driven by the radio synchrotron signal produced by e ± final states propagating in the magnetic field in the vicinity of the BH. We find that for DM masses m χ up to the TeV scale XTE J1118+480 allows to constrain ⟨σv⟩ well below the standard value ⟨σv⟩thermal, corresponding to the observed DM relic density in the Universe for a thermal WIMP. On the other hand, for m χ ≳ 15 GeV, the bounds from the SMBHs in the GC or in M87 do not reach ⟨σv⟩thermal when the very large uncertainties on the corresponding spike indices are taken into account, in spite of potentially producing much larger DM densities compared to XTE J1118+480. Our bounds for XTE J1118+480 have a mild sensitivity on the effect of spatial diffusion (which implies at most a weakening of the bounds of a factor ≲ 6 at large m χ). However, diffusion is instrumental in enhancing the sensitivity of the results upon the intensity of the magnetic field. In particular, our bounds rest on the assumption that the magnetic field B reaches the equipartition value B eq. We find that a reduction factor of the magnetic field B eq/B larger than about 14 at low m χ, becoming progressively smaller at higher WIMP masses, would be sufficient to relax the XTE J1118+480 bound to the level of other existing bounds. Recent estimates, albeit not conclusive, may suggest values of B eq/B in BH-LMXB systems as large as 20. This implies that the intensity of the magnetic field in BH-LMXB systems represents the major uncertainty in using them as an alternative to heavier BHs to search for WIMPs.

Extreme single-excitation subradiance from two-band Bloch oscillations in atomic arrays

Atomic arrays provide an important quantum optical platform with photon-mediated dipole–dipole interactions that can be engineered to realize key applications in quantum information processing. A major obstacle for such applications is the fast decay of the excited states. By controlling two-band Bloch oscillations of single excitation in an atomic array under an external magnetic field, here we show that exotic subradiance can be realized and maintained with orders of magnitude longer than the spontaneous decay time in atomic arrays with the finite size. The key finding is to show a way for preventing the wavepacket of excited states scattering into the dissipative zone inside the free space light cone, which therefore leads to the excitation staying at a subradiant state for an extremely long decay time. We show that such operation can be achieved by introducing a spatially linear potential from the external magnetic field in the atomic arrays and then manipulating interconnected two-band Bloch oscillations along opposite directions. Our results also point out the possibility of controllable switching between superradiant and subradiant states, which leads to potential applications in quantum storage.

On uniqueness properties of solutions of the generalized fourth-order Schrödinger equations

In this paper, we study uniqueness properties of solutions to the generalized fourth-order Schrödinger equations in any dimension d of the following forms, i∂tu+∑j=1d∂xj4u=Vt,xu,andi∂tu+∑j=1d∂xj4u+Fu,u‾=0. We show that a linear solution u with fast enough decay in certain Sobolev spaces at two different times has to be trivial. Consequently, if the difference between two nonlinear solutions u 1 and u 2 decays sufficiently fast at two different times, it implies that u1≡u2 .

Immunisation efficacy of a stabilised SARS-CoV-2 spike glycoprotein in two geriatric animal models

Age is associated with reduced efficacy of vaccines and linked to higher risk of severe COVID-19. Here we determined the impact of ageing on the efficacy of a SARS-CoV-2 vaccine based on a stabilised Spike glycoprotein (S-29) that had previously shown high efficacy in young animals. Thirteen to 18-month-old golden Syrian hamsters (GSH) and 22–23-month-old K18-hCAE2 mice were immunised twice with S-29 protein in AddaVaxTM adjuvant. GSH were intranasally inoculated with SARS-CoV-2 either two weeks or four months after the booster dose, while all K18-hACE2 mice were intranasally inoculated two weeks after the second immunisation. Body weight and clinical signs were recorded daily post-inoculation. Lesions and viral load were investigated in different target tissues. Immunisation induced seroconversion and production of neutralising antibodies; however, animals were only partially protected from weight loss. We observed a significant reduction in the amount of viral RNA and a faster viral protein clearance in the tissues of immunized animals. Infectious particles showed a faster decay in vaccinated animals while tissue lesion development was not altered. In GSH, the shortest interval between immunisation and inoculation reduced RNA levels in the lungs, while the longest interval was equally effective in reducing RNA in nasal turbinates; viral nucleoprotein amount decreased in both tissues. In mice, immunisation was able to improve the survival of infected animals. Despite the high protection shown in young animals, S-29 efficacy was reduced in the geriatric population. Our research highlights the importance of testing vaccine efficacy in older animals as part of preclinical vaccine evaluation.

Quantitative stochastic homogenization of nonlinearly elastic, random laminates

In this paper we study quantitative stochastic homogenization of a nonlinearly elastic composite material with a laminate microstructure. We prove that for deformations close to the set of rotations, the homogenized stored energy function W_{\hom} is C^{3} and that W_{\hom} , the stress tensor DW_{\hom} , and the tangent-moduli D^{2}W_{\hom} can be represented with the help of stochastic correctors. Furthermore, we study the error of an approximation of these quantities via representative volume elements. More precisely, we consider periodic representative volume elements (RVEs) obtained by periodizing the distribution of the random material. For materials with a fast decay of correlations on scales larger than a unit scale, we establish error estimates on the random and systematic error of the RVE with optimal scaling in the size of the RVE and with a multiplicative random constant that has exponential moments.

Setting Up a Large-Eddy Simulation to Focus on the Atmospheric Surface Layer

Large-eddy simulations (LES) above forests and cities typically constrain the simulation domain to the first 10–20% of the Atmospheric Boundary Layer (ABL), aiming to represent the finer details of the roughness elements and sublayer. These simulations are also commonly driven by a constant pressure gradient term in the streamwise direction and zero stress at the top, resulting in an unrealistic fast decay of the total stress profile. In this study, we investigate five LES setups, including pressure and/or top-shear driven flows with and without the Coriolis force, with the aim of identifying which option best represents turbulence profiles in the atmospheric surface layer (ASL). We show that flows driven solely by pressure not only result in a fast-decaying stress profile, but also in lower velocity variances and higher velocity skewnesses. Top-shear driven flows, on the other hand, better replicate ASL statistics. Overall, we recommend, and provide setup guidance for, simulation designs that include both a large scale pressure forcing and a non-zero stress and scalar flux at the top of the domain, and that also represent the Coriolis force. Such setups retain all the forces used in typical full ABL cases and result in the best match of the profiles of various statistical moments.

Self‐Powered Photodetector Based on Perovskite/Ge Heterojunction with High Responsivity

AbstractSelf‐powered photodetectors (SPDs) are regarded as a new type of photodetectors without external energy sources, exhibiting great potential in the next generation of image sensing, biological detection, and robotics. Here, single crystal CH(NH2)2PbBr3 (FAPbBr3) perovskite with a low trap density of 1.64 × 109 cm−3 is directly integrated onto single crystal germanium (Ge). The band structure of the heterojunction belongs to type‐II alignment type, which is beneficial to the achievement of high responsivity. Therefore, the fabricated Au/FAPbBr3/Ge/Au detector exhibits a high responsivity of 0.33 A W−1, detectivity up to 3.83 × 1011 Jones and relatively fast decay time of 4.94 ms without external bias under 520 nm laser illumination. In addition, a prototype of an imaging system is set up utilizing the photodetector as a sensing pixel, from which the imaging function is verified. This work demonstrates a facile strategy for designing high‐performance SPDs.

The Importance of Fluency in Reading: A Comparison of English, Swedish, Croatian, and Estonian

We report results from children learning to read in one of four different languages: Croatian, English, Estonian and Swedish. The languages all have an alphabetical script but vary greatly on the dimension deep-shallow (or complexity-simplicity, or opacity-transparency), i.e., how close orthography and phonology are related. These languages also vary in the complexity and type of grammatical structure. We used tasks to measure phonological awareness, morpho-syntactic processing, word and pseudoword identification speed, working memory, and reading comprehension. In English, Swedish, and Croatian, fluency was the most significant predictor of reading comprehension. In Estonian, morpho-syntactic awareness was the most significant predictor, although reading fluency was a close second. Fluency was of primary importance in reading comprehension because the limitations of working memory result in fast decay of input information. Therefore, it is important to read with fluency for proper text comprehension.