We discuss Tsallis holographic dark energy (THDE) model in higher dimension. An interacting dark energy model is proposed with Generalized Chaplygin Gas (GCG) in the framework of Compact Kaluza-Klein ...gravity. It is shown that a stable configuration can be found in the present epoch which is also compatible with the observed value of the density parameter. It is noted that dark energy (DE) might have evolved from a phantom phase in the past. Nature of dark energy is found to depend on the coupling parameter of the interaction. Classical stability consideration is also found to put an upper bound on the model parameter.
Purpose
Turbid (powder or columnar‐structured) scintillators are widely used in indirect flat panel detectors (I‐FPDs) for scientific, industrial, and medical radiography. Light diffusion and ...absorption within these scintillators is expected to cause depth‐dependent variations in their x ray conversion gain and spatial blur. These variations degrade the detective quantum efficiency of I‐FPDs at all spatial frequencies. Despite their importance, there are currently no established methods for directly measuring scintillator depth effects. This work develops the instrumentation and methods to achieve this capability.
Methods
An ultra‐high‐sensitivity camera was assembled for imaging single x ray interactions in two commercial Gd2O2S:Tb (GOS) screens (Lanex Regular and Fast Back, Eastman Kodak Company). X ray interactions were localized to known depths in the screens using a slit beam of parallel synchrotron radiation (32 keV), with beam width (~20 μm) much narrower than the screen thickness. Depth‐localized x ray interaction images were acquired in 30 μm depth‐intervals, and analyzed to measure each scintillator's depth‐dependent average gain g¯(z) and modulation transfer function MTF(z,f). These measurements were used to calculate each screen's expected MTF(f) in an energy‐integrating detector (e.g., I‐FPD). Calculations were compared to presampling MTF measurements made by coupling each screen to a high‐resolution CMOS image sensor (48 μm pixel) and using the slanted‐edge method.
Results
Both g¯(z) and MTF(z,f) continuously increased as interactions occurred closer to each screen's sensor‐coupled surface. The Regular yielded 1351 ± 66 and 2117 ± 54 photons per absorbed x ray (42–66 keV−1) in interactions occurring furthest from and nearest to the image sensor, while the Fast Back yielded 833 ± 22 and 1910 ± 39 photons (26–60 keV−1). At f = 1 mm−1, MTF(z,f) varied between 0.63 and 0.78 in the Regular and 0.30–0.76 in the Fast Back. Calculations of presampling MTF(f) using g¯(z) and MTF(z,f) showed excellent agreement with slanted‐edge measurements.
Conclusions
The developed instrument and method enable direct measurements of the depth‐dependent gain and spatial resolution of turbid scintillators. This knowledge can be used to predict, understand, and potentially improve I‐FPD imaging performance.
Blockchain technology is facing critical issues of scalability, efficiency and sustainability. These problems are necessary to solve if blockchain is to become a technology that can be used ...responsibly. Useful quantum computers could potentially be developed by the time that blockchain will be widely implemented for mission-critical work at financial and other institutions. Quantum computing will not only cause challenges for blockchain, but can also be harnessed to better implement parts of blockchain technologies including cryptocurrencies. We review the work that has been done in the area of quantum blockchain and hybrid quantum–classical blockchain technology and discuss open questions that remain.
Massive, thick-walled pressure vessels are permanent nuclear reactor structures that are exposed to a damaging flux of neutrons from the adjacent core. The neutrons cause embrittlement of the vessel ...steel that grows with dose (fluence), as manifested by an increasing ductile-to-brittle fracture transition temperature. Extending reactor life requires demonstrating that large safety margins against brittle fracture are maintained at the higher neutron fluence associated with beyond 60years of service. Here synchrotron-based x-ray diffraction and small angle x-ray scattering measurements are used to characterize highly embrittling nm-scale Mn–Ni–Si precipitates that develop in the irradiated steels at high fluence. These precipitates lead to severe embrittlement that is not accounted for in current regulatory models. Application of the complementary techniques has, for the very first time, successfully identified the crystal structures of the nanoprecipitates, while also yielding self-consistent compositions, volume fractions and size distributions.
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For increasing land use efficiency and weed suppression intercropping plays a pivotal role. A field experiment was carried out on wheat (
Triticum aestivum L. emend. Fiori and Paol)–chickpea (
Cicer ...arietinum L.) mono- and intercropping with various weeding (0, 1, or 2 hand-weeding operations) and row spacing (20- or 30-cm) treatments in the eastern plateau region of India over consecutive five winter seasons (1997/2001). The experimental design was a randomized complete block with eighteen treatments replicated thrice. Significant (
P
≤
0.05) differences were observed in yield and economics with and without weeding treatments. Chickpea yield was significantly reduced by wheat when intercropped. However, total productivity and land use efficiency were higher under the intercropping system as compared to monocrops of either species. There was a significant reduction in weed density and biomass for the intercropping system over both monocrops. Wheat facilitated an increase in nodule number and dry weight in chickpea under intercropping over monocrops, moreover, root length of chickpea was greater when intercropped. These findings suggest that intercropping wheat and chickpea increase total productivity per unit area, improve land use efficiency and suppress weeds, a menacing pest in crop production. Considering the experimental findings, wheat–chickpea (30
cm) with two weedings may be recommended for yield advantage, higher net income, more efficient utilization of resources, and weed suppression as a biological control in eastern plateau region of India.
Solar cells based on hybrid perovskites have shown high efficiency while possessing simple processing methods. To gain a fundamental understanding of their properties on an atomic level, we ...investigate single crystals of CH
NH
PbI
with a narrow transition (~5 K) near 327 K. Temperature dependent structural measurements reveal a persistent tetragonal structure with smooth changes in the atomic displacement parameters (ADPs) on crossing T*. We show that the ADPs for I ions yield extended flat regions in the potential wells consistent with the measured large thermal expansion parameter. Molecular dynamics simulations reveal that this material exhibits significant asymmetries in the Pb-I pair distribution functions. We also show that the intrinsically enhanced freedom of motion of the iodine atoms enables large deformations. This flexibility (softness) of the atomic structure results in highly localized atomic relaxation about defects and hence accounts for both the high carrier mobility as well as the structural instability.
Recently, Wang and Ma (Quantum Inf Process 16(5):130,
2017
) proposed two interesting quantum key agreement protocols with a single photon in both polarization and spatial-mode degrees of freedom. ...They claimed that the privacy of participants’ secret keys in the multiparty case is protected against dishonest participants. However, in this paper, we prove that two dishonest participants can deduce the secret key of an honest one using a fake sequence of single photons, without being detected. Also, we propose an additional security detection process to avoid the security loophole in their protocol.
IG-430, a fine-grained, isotropic graphite grade is a promising candidate for the future Very High Temperature Reactors (VHTR). IG-430 which provides higher density, strength, and thermal ...conductivity, has already been developed as a graphite for next-generation HTGR, and is expected to be employed. This graphite grade, however, is lacking enough database that is needed for design. The present study aims to enhance the database with experimental data focusing on the low temperature regime (90–210 °C) by using 120–200 MeV protons to irradiate the IG-430 graphite to peak fluence of ~1.2 1025 m−2. It is anticipated that radiation-induced changes in the graphite properties and damage to be more pronounced in this low temperature regime than in elevated temperatures where damage annealing is taking place simultaneously. IG-430 graphite was characterized following irradiation for mechanical property changes (modulus and strength), dimensional stability and irradiation-induced growth as well as microstructural changes using high energy X-rays and different X-ray diffraction techniques. In assessing proton irradiation effects on the IG-430 graphite grade, comparison of radiation effects was made with the IG-43 grade, the un-purified version of IG-430, as well as other isotropic graphite grades. IG-430 was shown in this study to be better graphitized than other isotropic graphite grades. The study also revealed that during proton irradiation at low temperatures (~100 °C) the IG-430 exhibits stored energy release.
Mice with a mutation in the Clock gene (ClockΔ19) have been identified as a model of mania; however, the mechanisms that underlie this phenotype, and the changes in the brain that are necessary for ...lithium's effectiveness on these mice remain unclear. Here, we find that cholecystokinin (Cck) is a direct transcriptional target of CLOCK and levels of Cck are reduced in the ventral tegmental area (VTA) of ClockΔ19 mice. Selective knockdown of Cck expression via RNA interference in the VTA of wild-type mice produces a manic-like phenotype. Moreover, chronic treatment with lithium restores Cck expression to near wild-type and this increase is necessary for the therapeutic actions of lithium. The decrease in Cck expression in the ClockΔ19 mice appears to be due to a lack of interaction with the histone methyltransferase, MLL1, resulting in decreased histone H3K4me3 and gene transcription, an effect reversed by lithium. Human postmortem tissue from bipolar subjects reveals a similar increase in Cck expression in the VTA with mood stabilizer treatment. These studies identify a key role for Cck in the development and treatment of mania, and describe some of the molecular mechanisms by which lithium may act as an effective antimanic agent.
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