In this paper, we investigate the nonlinear fractional difference equation with nonlocal fractional boundary conditions. We derive the Green's function for this problem and show that it satisfies certain properties. Some existence results are obtained by means of nonlinear alternative of Leray-Schauder type theorem and Krasnosel-skii's fixed point theorem. 相似文献
Spatiotemporal dynamics of a predator–prey system in presence of spatial diffusion is investigated in presence of additional food exists for predators. Conditions for stability of Hopf as well as Turing patterns in a spatial domain are determined by making use of the linear stability analysis. Impact of additional food is clear from these conditions. Numerical simulation results are presented in order to validate the analytical findings. Finally numerical simulations are carried out around the steady state under zero flux boundary conditions. With the help of numerical simulations, the different types of spatial patterns (including stationary spatial pattern, oscillatory pattern, and spatiotemporal chaos) are identified in this diffusive predator–prey system in presence of additional food, depending on the quantity, quality of the additional food and the spatial domain and other parameters of the model. The key observation is that spatiotemporal chaos can be controlled supplying suitable additional food to predator. These investigations may be useful to understand complex spatiotemporal dynamics of population dynamical models in presence of additional food. 相似文献
Transition Metal Chemistry - In this paper, four diiron toluene-3,4-dithiolate complexes with phosphine ligands were synthesized and characterized. Treatment of complex... 相似文献
Cervical cancer is the second most common cancer in the world’s woman population with a high incidence in developing countries where diagnostic conditions for the cancer are poor. The main culprit causing the cancer is the human papillomavirus (HPV). HPV is divided into three major groups, i.e., high-risk (HR) group, probable high-risk (pHR) group, and low-risk (LR) group according to their potential of causing cervical cancer. Therefore, developing a sensitive, reliable, and cost-effective point-of-care diagnostic method for the virus genotypes in developing countries even worldwide is of high importance for the cancer prevention and control strategies. Here we present a combined method of isothermal recombinase polymerase amplification (RPA), lateral flow dipstick (LFD), and reverse dot blot (RDB), in quick point-of-care identification of HPV genotypes. The combined method is highly specific to HPV when the conserved L1 genes are used as targeted genes for amplification. The method can be used in identification of HPV genotypes at point-of-care within 1 h with a sensitivity of low to 100 fg of the virus genomic DNA. We have demonstrated that it is an excellent diagnostic point-of-care assay in monitoring the disease without time-consuming and expensive procedures and devices.
In order to measure the color of different samples with different surface texture, multiple measurement and observation conditions are needed from the instrument. Thus, both SCI (specular component included) and SCE (specular component excluded) measurement conditions are included in most color measuring instruments today. In current design, a light trap is established in the integrating sphere, and the instrument uses mechanical control to switch between SCI and SCE measurement modes. However, establishing a light trap inside the integrating sphere will affect the SCI and SCE measurement results. This article discusses the problems in current design, proposes a dual light source structure that includes both SCI and SCE measurement conditions, and then evaluates the structure with experiments. The experiment results show that the improved structure is more suitable for color measuring instruments with both SCI and SCE modes, and it has high practical value. 相似文献
Wedge-shaped molecules, such as dendrons, are among the most important building blocks for directed supramolecular self-assembly. Here we present a new approach aimed at widening the range and complexity of potential mesophases by introducing double-tapered mesogens. Two series of compounds are presented, both alkali metal salts (Li, Na, Cs) of 3,4,5-tris-alkoxybenzoic acid with a second tapered tris-alkoxyaryl group attached at the end of an alkoxy chain. The double-tapered compounds all display an unusual hexagonal columnar phase consisting of one ionic and three non-ionic columns per unit cell. The cation size has an unexpectedly drastic effect on unit cell size. Unlike most columnar phases, the current phases show unusually high dimensional stability on heating, and high stiffness in spite of being 80–85 % aliphatic, attributed to their molecular topology. The described approach may lead to co-assemblies of multifunctional materials, for example, parallel p- and n-semiconducting nanowires or parallel ionic and electronic conductors. 相似文献
A new decoupled two-gird algorithm with the Newton iteration is proposed for solving the coupled Navier-Stokes/Darcy model which describes a fluid flow filtrating through porous media. Moreover the err... 相似文献
In this work, the two-dimensional MoS2 film was prepared by sulfuring the molybdenum atomic layer on SiO2/Si substrate. The reaction temperature, heating rate, holding time and carrier gas flow rate were investigated comprehensively. The quality of MoS2 film was characterized by optical microscopy, atomic force microscopy, Raman and photoluminescence spectroscopy. The characterization results showed that the optimum synthesis parameters were heating rate of 25 °C/min, reaction temperature of 750 °C, holding time of 30 min and carrier gas velocity of 100 sccm. The MoS2 gas sensor was fabricated and its gas sensing performance was tested. The test results indicated that the sensor had a good response to both reducing gas (NH3) and oxidizing gas (NO2) at room temperature. The sensitivity to 100 ppm of NO2 was 31.3%, and the response/recovery times were 4 s and 5 s, respectively. In addition, the limit of detection could be as low as 1 ppm. This work helps us to develop low power and integrable room temperature NO2 sensors. 相似文献