Characteristics of Local Modulation Beam Propagating through Spatial Filter System

As local defects may significantly harm beam quality and affect safe operation, a systematic analysis of the ability of a spatial filter to alleviate these adverse effects is required. Thus, the evolutional characteristics of a beam modulated by a local defect propagating through a spatial filter system at an image reply plane and a downstream plane are analyzed in detail. Modulation stripes appear at the image reply plane; these are caused by the pinhole cutoff effect. The modulation degree increases with increasing defect size. The maximum intensification factor can reach 3.2 under certain conditions. Thus, the defect size should be restricted to a reasonable size for safe operation with a specified pinhole size. Moreover, a maximal value appears at the downstream plane, and the intensity enhances with increasing defect size. To ensure beam quality, the maximum allowable defect size and angle of the spatial filter should meet special constraints. The maximum allowable defect size is calculated based on practical configuration parameters

Effect of processing parameters on microstructure of MoS2 ultra-thin films synthesized by chemical vapor deposition method

MoS2 ultra-thin layers are synthesized using a chemical vapor deposition method based on the sulfurization of molybdenum trioxide (MoO3). The ultra-thin layers are characterized by X-ray diffraction (XRD), photoluminescence (PL) spectroscopy and atomic force microscope (AFM). Based on our experimental results, all the processing parameters, such as the tilt angle of substrate, applied voltage, heating time and the weight of source materials have effect on the microstructures of the layers. In this paper, the effects of such processing parameters on the crystal structures and morphologies of the as-grown layers are studied. It is found that the film obtained with the tilt angle of 0.06° is more uniform. A larger applied voltage is preferred to the growth of MoS2 thin films at a certain heating time. In order to obtain the ultra-thin layers of MoS2, the weight of 0.003 g of source materials is preferred. Under our optimal experimental conditions, the surface of the film is smooth and composed of many uniformly distributed and aggregated particles, and the ultra-thin MoS2 atomic layers (1∼10 layers) covers an area of more than 2 mm×2 mm

Synthesis and characterization of phenylboronic acid-containing polymer for glucose-triggered drug delivery+

Thermo-, pH- and glucose-responsive polymeric nanoparticles are of great interest in developing a self-regulated drug delivery system. The novel core-shell nanoparticles were synthesized by self-assembly of a phenylboronic acid-based block copolymer poly-(N-isopropylacrylamide)-block-poly(3-acrylamidophenylboronic acid) (PNIPAM136-b-PAPBA16) and a fluorescent complex glucosamine-poly(N-isopropylacrylamide)/Eu(III) (GA-PNIPAM)/Eu(III) based on the cross-linking between PBA- and GA-containing blocks in this work. The nanoparticles can be tuned via thermo-induced collapse or glucose-induced swelling at appropriate pH and temperatures; they had an average kinetic radius was about 80nm, and which showed excellent fluorescence. MTT assays revealed the nanocarriers had no significant cytotoxic response of the micelle when it was observed in the cell line over the concentration range from 0.1 to 1000 μg/ml at any exposure times

Design of a Broadband Perfect Solar Absorber Based on a Four-Layer Structure with a Cross-Shaped Resonator and Triangular Array

As solar energy is a low-cost and clean energy source, there has been a great deal of interest in how to harvest it. To absorb solar energy efficiently, we designed a broadband metamaterial absorber based on the principle of Fabry–Pérot (FP) cavities and surface plasmon resonance (SPR). We propose a broadband perfect absorber consisting of a four-layer structure of silica–tungsten–silica–titanium (SiO2–W–SiO2–Ti) for the incident light wavelength range of 300–2500 nm. The structure achieves perfect absorption of incident light in the wavelength range of 351.8–2465.0 nm (absorption > 90%), with an average absorption of 96.3%. The advantage of our proposed structure is that it combines the characteristics of both high and broadband absorption, and has high overall absorption efficiency for solar radiation. It is also independent of polarization and insensitive to incident angle. We investigated how absorption was affected by different structures, materials, geometric parameters, and refractive indices for different dielectric materials, and we explored the reasons for high absorption. This structure is refractory and ultrathin, and it offers a good tradeoff between bandwidth and absorption. It therefore has premium application prospects and value

Effective and Selective DNA Modification on Bacterial Membranes

With highly precise self-assembly and programmability, DNA has been widely used as a versatile material in nanotechnology and synthetic biology. Recently, DNA-based nanostructures and devices have been engineered onto eukaryotic cell membranes for various exciting applications in the detection and regulation of cell functions. While in contrast, the potential of applying DNA nanotechnology for bacterial membrane studies is still largely underexplored, which is mainly due to the lack of tools to modify DNA on bacterial membranes. Herein, using lipid-DNA conjugates, we have developed a simple, fast, and highly efficient system to engineer bacterial membranes with designer DNA molecules. We have constructed a small library of synthetic lipids, conjugated with DNA oligonucleotides, and characterized their membrane insertion properties on various Gram-negative and Gram-positive bacteria. Simply after incubation, these lipid-DNA conjugates can be rapidly and efficiently inserted onto target bacterial membranes. Based on the membrane selectivity of these conjugates, we have further demonstrated their applications in differentiating bacterial strains and potentially in pathogen detection. These lipid-DNA conjugates are promising tools to facilitate the possibly broad usage of DNA nanotechnology for bacterial membrane analysis, functionalization, and therapy