The flexible nature and high surface-to-volume ratio make monolayer-MoS2 a novel paradigm for tunable nanoelectronic devices. However, for further improvement in the performance of these devices, a ...new design strategy is essential to modulate the properties of an inert MoS2 basal plane. Here, we demonstrate from first-principles that the gas adsorption and magnetic properties of MoS2 can be modulated through MoS antisite doping and strain. The MoS defect with localized d-orbital electron density significantly promotes the catalytic activity which leads to highly enhanced adsorption of NO, NO2, NH3, CO, and CO2 gas molecules. On application of a biaxial tensile strain, the adsorption of NH3 is further enhanced for the antisite-doped MoS2. In addition, strain-induced switching of magnetic states is also realized in antisite-doped MoS2 with and without adsorbed gas species. The superior strain modulation of antisite-doped MoS2 is explained by quantum confinement effect and strain-induced accumulation/depletion of charge density at the defect site. These results suggest that antisite-doped MoS2 can be a promising avenue to design nanoscale spintronic devices and gas sensors.
Run and slow control system of the Belle II silicon vertex detector Irmler, C.; Aihara, H.; Aziz, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
958
Journal Article
Recenzirano
The Belle II Silicon Vertex Detector (SVD) was installed recently and has been prepared for physics run at SuperKEKB factory, Tsukuba, Japan. For a reliable operation and data taking of the SVD, a ...sophisticated and robust run and slow control system has been implemented, which utilizes the Experimental Physics and Industrial Control System (EPICS) framework. EPICS uses client/server and publish/subscribe techniques to communicate between the various sub-systems and computers. The information exchange between the different pieces of software and computers is done by process variables (PVs). These PVs are provided by input/output controllers (IOCs), which communicate and interface with the hardware components. The Belle II SVD slow and run control comprises five groups of subsystems, which are SVD DAQ controller, Flash ADC controller, environmental monitors and interlocks, power supplies and EPICS infrastructure services. In this paper we describe the tasks and the implementation of the individual sub-systems, the interaction between them and the global Belle II run and slow control as well as the first experience from commissioning and initial operation of the SuperKEKB accelerator.
The present research deals with the fabrication of mechanically alloyed W based alloys with nominal composition of W75Ni10Mo10Ti5 (alloy A), W74Ni10Mo10Ti5(Y2O3)1 (alloy B), W73Ni10Mo10Ti5(Y2O3)2 ...(alloy C) (all in wt%) by compaction at 500MPa pressure for 5min and conventional pressureless Ar injected sintering at 1500°C for 2h. The phase evolution, microstructure, thermal characteristics, mechanical and high temperature behavior of the mechanically alloyed powders and sintered alloys has been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS) and differential scanning calorimetry (DSC). Alloy C shows minimum crystallite size and maximum lattice strain, dislocation density of 18.6nm, 0.54%, 36.71×1016/m2 respectively at 20h of milling as compared to other alloys. The activation energy for recrystallization decreases with increase in Y2O3 dispersion. The residual stress also enhances with increased Y2O3 content. Alloy C exhibits improved relative sintered density, hardness and elongation of 92.1%, 7.22GPa, 12.73% respectively and appreciable wear resistance, high temperature oxidation resistance at 1000°C whereas maximum compressive strength of 1.91GPa has been recorded in alloy B as compared to other alloys. Most interestingly the ductility also enhances with increase in Y2O3 dispersion.
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•Nanostructured W-Ni-Mo-Ti-(0, 1, 2wt% Y2O3) alloys are fabricated by mechanical alloying and conventional sintering.•Increase in Y2O3 dispersion considerably reduces the activation energy for recrystallization.•Enhanced grain bimodality is achieved in W-Ni-Mo-Ti-2wt% Y2O3 alloy.•The density, hardness, wear resistance and ductility increase and strength decreases with increase in Y2O3 addition.•W-Ni-Mo-Ti-2wt% Y2O3 alloy exhibits superior resistance against oxidation at 1000°C as compared other alloys.
Cast magnesium-metal matrix composites are widely used in automotive and aerospace industries due to high strength-to-weight ratio and good damping properties. In the present work, a novel hybrid ...method has been adopted to fabricate TiC-TiB2 reinforced magnesium matrix composites. The reinforcement is formed in-situ from elemental Ti and B4C powders and molten Mg-Al-Zn alloy without any addition of a third phase metal powder such as aluminum. Results show that the distribution of TiC and TiB2 reinforcing phases in the magnesium matrix is more uniform when the composite is fabricated at 900°C for 2h. The base and composite materials were subjected to homogenization treatment which resulted in dissolution of β-Mg17Al12 phase into α-Mg matrix and enhances the strength and ductility by 22% and 50% in base and 17% and 50% in composite respectively. The enhancement of mechanical properties in the homogenized in-situ composites is explained in detail by analyzing the fractographs and microstructures of the material.
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•A novel method has been adopted to fabricate in-situ TiC-TiB2 reinforced magnesium matrix hybrid composites.•The novel method is proven to develop such in-situ hybrid composite without addition of a third phase metal powder.•The in-situ reaction mechanism has been established.•A homogenization treatment has been implemented to the in-situ composites to enhance the strength and ductility.
The present paper is devoted to the study of bouncing cosmology in f(R,T) modified gravity where we presume f(R,T)=R+2λT, with R the Ricci scalar, T the trace of energy–momentum tensor and λ the ...model parameter. We present here a novel parametrization of Hubble parameter which is apt in representing a successful bouncing scenario undergoing no singularity. We proceed to present a complete analysis of the proposed bouncing model by studying the evolution of primordial curvature perturbations, energy conditions and stability against linear homogeneous perturbations in flat space–time. We also delineate bouncing cosmology for the proposed model by employing Quintom matter. The present article further communicate for the first time that violation of energy–momentum materialize for both the contracting and expanding universes except for the bouncing epoch with energy flow directed away and into the matter fields for the contracting and expanding universe respectively. We further present a thorough investigation about the feasibility of the proposed bouncing scenario against first and generalized second law of thermodynamics. We found that the proposed bouncing scenario obeys the laws of thermodynamics for the constrained parameter space of λ. The manuscript conclude after investigating the viability of the proposed bouncing model in non minimal f(R,T) gravity where f(R,T)=R+χRT.
Doxorubicin (DOX) is a broad-spectrum anthracycline antibiotic used to treat a variety of cancers including leukemia. Chronic myeloid leukemia (CML) blasts like K562 cells are resistant to apoptosis ...induced by DOX due to several reasons, the primary being the sequestration of drug into cytoplasmic vesicles and induction of multidrug resistance (MDR) gene expression with DOX treatment resulting in intracellular resistance to this drug. Moreover, expression of antiapoptotic protein BCL-2 and the hybrid gene bcr/abl in K562 cells contributes resistance to DOX. Studies have shown that curcumin (CUR) has a pleiotropic therapeutic effect in cancer treatment, as it is an inhibitor of nuclear factor kappa B (NFκB) as well as a potent downregulator of MDR transporters. In this study, we investigated the potential benefit of using DOX and CUR in a single nanoparticle (NP) formulation to inhibit the development of drug resistance for the enhancement of antiproliferative activity of DOX in K562 cells. Results illustrate that the dual (DOX+CUR) drug loaded NPs were effectively delivered into K562 cells. CUR not only facilitates the retention of DOX in nucleus for a longer period of time but also inhibits the gradual expression of MDR1 and BCL-2 at the mRNA level in K562 cells. Moreover, Western blot results confirm that in combination both of the drugs were capable of inducing apoptosis even if in a lower concentration compared to either single drug in both solution or in formulation. Combinational therapy by using DOX and CUR, especially when administered in the NP formulation, has enhanced the cytotoxicity in K562 cells by promoting the apoptotic response. Overall, this combinational strategy has significant promise in the clinical management of intractable diseases, especially leukemia.
Rice genome sequencing projects have generated remarkable amount of information about genes and genome architecture having tremendous potential to be utilized in both basic and applied research. ...Success in transgenics is paving the way for preparing a road map of functional genomics which is expected to correlate action of a gene to a trait in cellular and organismal context. However, the lack of a simple and efficient method for transformation and regeneration is a major constraint for such studies in this important cereal crop.
In the present study, we have developed an easy, rapid and highly efficient transformation and regeneration protocol using mature seeds as explants and found its successful applicability to a choice of elite indica rice genotypes. We have optimized various steps of transformation and standardized different components of the regeneration medium including growth hormones and the gelling agent. The modified regeneration medium triggers production of large number of shoots from smaller number of calli and promotes their faster growth, hence significantly advantageous over the existing protocols where the regeneration step requires maximum time. Using this protocol, significantly higher transformation efficiency (up to 46%) and regeneration frequency (up to 92% for the untransformed calli and 59% for the transformed calli) were achieved for the four tested cultivars. We have used this protocol to produce hundreds of independent transgenic lines of different indica rice genotypes. Upon maturity, these transgenic lines were fertile thereby indicating that faster regeneration during tissue culture did not affect their reproductive potential.
This speedy, yet less labor-intensive, protocol overcomes major limitations associated with genetic manipulation in rice. Moreover, our protocol uses mature seeds as the explant, which can easily be obtained in quantity throughout the year and kept viable for a long time. Such an easy, efficient and generalized protocol has the potential to be a major tool for crop improvement and gene-function studies on the model monocot plant rice.
•A generalized 2D multi-level thresholding criterion function is proved rigorously by mathematical induction method.•A multi-level thresholding scheme for a RGB color image is proposed.•PSO algorithm ...is applied to seek to optimal threshold values in a very reasonable computational time.•The segmented image is compared with the human segmentation from BSDS300 to evaluate the experiment results quantitatively and objectively.
In this paper, we propose a multi-level thresholding model based on gray-level & local-average histogram (GLLA) and Tsallis–Havrda–Charvát entropy for RGB color image. We validate the multi-level thresholding formulation by using the mathematical induction method. We apply particle swarm optimization (PSO) algorithm to obtain the optimal threshold values for each component of a RGB image. By assigning the mean values from each thresholded class, we obtain three segmented component images independently. We conduct the experiments extensively on The Berkeley Segmentation Dataset and Benchmark (BSDS300) and calculate the average four performance indices (BDE, PRI, GCE and VOI) to show the effectiveness and reasonability of the proposed method.
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