Karstensenrohde4337

We study a frustrated two-leg spin ladder with alternate isotropic Heisenberg and Ising rung exchange interactions, whereas, interactions along legs and diagonals are Ising-type. All the interactions in the ladder are anti-ferromagnetic in nature and induce frustration in the system. This model shows four interesting quantum phases (i) stripe rung ferromagnetic (SRFM), (ii) stripe rung ferromagnetic with edge singlet (SRFM-E), (iii) anisotropic antiferromagnetic (AAFM), and (iv) stripe leg ferromagnetic (SLFM) phase. We construct a quantum phase diagram for this model and show that in stripe rung ferromagnet (SRFM), the same type of sublattice spins (either isotropicS-type or discrete anisotropicσ-type spins) are aligned in the same direction. Whereas, in anisotropic antiferromagnetic phase, bothSandσ-type of spins are anti-ferromagnetically aligned with each other, two nearestSspins along the rung form an anisotropic singlet bond whereas two nearestσspins form an Ising bond. In large Heisenberg rung exchange interaction limit, spins on each leg are ferromagnetically aligned, but spins on different legs are anti-ferromagnetically aligned. The thermodynamic quantities like specific heatCv(T), magnetic susceptibilityχ(T) and thermal entropyS(T) are also calculated using the transfer matrix method for various phases. The magnetic gap in the SRFM and the SLFM can be noticed fromχ(T) andCv(T) curves.Integration of graphene with semiconducting quantum dots (QDs) provides an elegant way to access the intrinsic properties of graphene and optical properties of QDs concurrently to realize the high-performance optoelectronic devices. In the current article, we have demonstrated the high-performance photodetector based on graphene CdSe QDs/CdS nanorod heterostructures. The resulting heterojunction photodetector with device configuration ITO/graphene CdSe/CdS nanorods/Ag show excellent operating characteristics including a maximum photoresponsivity of 15.95 AW-1and specific detectivity of 6.85 × 1012Jones under 530 nm light illumination. The device exhibits a photoresponse rise time of 545 ms and a decay time of 539 ms. Furthermore, the study of the effect of graphene nanosheets on the performance enhancement of heterojunction photodetector is carried out. The results indicate that, due to the enhanced energy transfer from photoexcited QDs to graphene layer, light absorption is increased and excitons are generated led to the enhancement of photocurrent density. In addition to that, the graphene CdSe QDs/CdS nanorod interface can facilitate charge carrier transport effectively. This work provides a promising approach to develop high-performance visible-light photodetectors and utilizing advantageous features of graphene in optoelectronic devices.Objective. Music is one of the most sublime stimuli that human beings can experience. Despite being just an acoustic wave that exerts little physical influence on a subject, it triggers profound changes in emotions and physiological states. This study explores the possibility of detecting subtle changes in cerebral blood flow velocity in response to emotional reactions produced by different musical stimuli using multiscale entropy analysis.Approach. Cerebral blood flow signals were successfully recorded for 16 subjects while performing five different musical tasks. The entropy of each signal was estimated using multiscale sample entropy.Main results. This method has been shown to be capable of revealing the complexity of the internal dynamics of different physiological systems, which cannot be appreciated with classic approaches based on entropy on a single scale.Significance. Significant differences in entropy were found between two of the tasks, which suggests that intense cognitive activities with emotional content cause a decrease in the entropy of cerebral haemodynamics.Novel electronic systems displaying exotic physical properties can be derived from complex topological materials through chemical doping. MoTe2, the candidate type-II Weyl semimetal shows dramatically enhanced superconductivity up to 4.1 K upon Re doping in Mo sites. Based on bulk transport and local scanning tunnelling microscopy here we show that Re doping also leads to the emergence of a possible charge density wave phase in Re0.2Mo0.8Te2. In addition, the tunnellingI-Vcharacteristics display non-linearity and hysteresis which is commensurate with a hysteresis observed in the change in tip-height (z) as a function of applied voltageV. The observations indicate an electric field induced hysteretic switching consistent with piezoelectricity and possible ferroelectricity.Objective. Lead (Pb) is a well-known toxic element.In vivobone Pb concentration measurement is a long-term exposure metric complementary to blood Pb concentration measurement which is a metric of recent exposure.In vivohuman tibia bone Pb measurements using Pb K-shell or L-shell x-ray fluorescence (KXRF or LXRF) emissions were developed in the 1980s. KXRF bone Pb measurements using Cd-109 gamma rays and coherent-to-fluorescence ratio to account for differences between phantom andin vivomeasurements, was employed in human studies. Bone Pb LXRF method employed x-ray tubes. However, calibration procedures using ultrasound measurements of the soft tissue thickness (STT) proved inaccurate.Approach. In this study, bone and soft tissue (ST) phantoms simulatedin vivobone Pb measurements. Seven plaster-of-Paris cylindrical bone phantoms containing 1.01 mg g-1of strontium (Sr) were doped with Pb in 0, 8, 16, 29, 44, 59, and 74 μg g-1concentrations. Polyoxymethylene (POM), resin, and wax were each used to fabricate four ST phantoms in the approximate 1-4 mm thickness range. Pb LXRF measurements were performed using a previously developed optimal grazing incidence position method.Main results. Linear attenuation coefficients measurements of ST materials indicated that POM and resin mimicked well attenuation of Pb x-rays in skin and adipose tissue, respectively. POM and resin data indicated a bone Pb detection limit of 20 μg g-1for a 2 mm STT. Derived relationships between the Pb concentration, Pb LXRF and Sr Kβ/Kαratio data did not require STT knowledge. Applied to POM and resin data, the new calibration method yielded unbiased results.Significance.In vivobone Pb measurements in children were suggested following considerations of radiation dose, STT, detectability and distribution of Pb and Sr in bone. ITF2357 This research meets with the concerns regarding the negative effects of low levels of Pb exposure on neurodevelopment of children.