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Surface tension provides microbubbles (MB) with a perfect spherical shape. Here, we demonstrate that MB can be engineered to be nonspherical, endowing them with unique features for biomedical applications. Anisotropic MB were generated via one-dimensionally stretching spherical poly(butyl cyanoacrylate) MB above their glass transition temperature. Compared to their spherical counterparts, nonspherical polymeric MB displayed superior performance in multiple ways, including i) increased margination behavior in blood vessel–like flow chambers, ii) reduced macrophage uptake in vitro, iii) prolonged circulation time in vivo, and iv) enhanced blood–brain barrier (BBB) permeation in vivo upon combination with transcranial focused ultrasound (FUS). Our studies identify shape as a design parameter in the MB landscape, and they provide a rational and robust framework for further exploring the application of anisotropic MB for ultrasound-enhanced drug delivery and imaging applications.

Van der Waals (vdW) layered GeTe-Sb 2 Te 3 superlattices (GST-SL) have attracted enormous attentions due to the ultralow power consumption for nonvolatile phase change memory. In this paper, effects of biaxial strain on interfacial intermixing and local structures in strain engineered GST-SL were studied. Highly (0 0 l ) textured GST-SL with thickness-varied Sb 2 Te 3 sublayers were fabricated by magnetron sputtering and investigated with multiple analyses on surfaces and interfaces. The appearance of Ge-Sb-Te alloys indicated the interfacial Ge/Sb intermixing in strain engineered GST-SL, which actually were composed of Sb 2 Te 3 quintuple layers, Ge-Sb-Te vdW layers and isolated GeTe bilayers. Grazing incidence x-ray diffraction (GID) and x-ray photoelectron spectroscopy (XPS) results revealed that biaxial strain not only facilitated the interfacial intermixing, but also caused the reconfiguration of Ge-Sb-Te vdW layers. Raman spectra indicated that vertical and in-plane vibrations of GeTe layers were not affected by the interfacial intermixing and the newly-formed Ge-Sb-Te layers had similar vibration characteristics as that of GeTe layers. A modified switching mechanism of GST-SL, relating to both the amorphous-crystalline phase transition of GeTe and Ge-Sb-Te layers incorporated into the Sb 2 Te 3 matrix, was then presented. The present studies shed new light on strain engineering for GST-SL and indicate their potential optoelectronic applications.

Phase change materials (PCMs) are highly promising for the digital-storage technology based on the fast phase transition between the crystal and amorphous states. In order to optimize the properties of PCMs, the doping of PCMs has become research hot points nowadays. In this paper, effects of Sn doping (0%, 10%, 30%) on the crystallization behavior of Ge2Sb2Te5 (GST) films induced by a picosecond pulsed laser with Gaussian energy profile were investigated experimentally. As compared to the previous study irradiated by a nanosecond pulsed laser, such factors as melting, ablation and crystallization thresholds dropped remarkably by a picosecond laser irradiation, and with the increase of Sn content those factors were further decreased. Due to the replacement of Ge atoms by Sn atoms, the Sn incorporation expanded the lattice constant so as to introduce the mechanical stress which, together with the thermal stress generated after laser irradiation, significantly affected the atomic movement during the crystallization process. High-resolution transmission electron microscopy (HRTEM) observations showed that GST with a lower Sn content of 10% tended to form sub-grain boundaries by local atomic shear to ensure long-range ordering of crystals, but with the increase of the Sn doping to 30%, the long-range ordering structure was broken, instead of some atoms arranged randomly, which were mainly Ge atoms, separating out from the lattice because of the replacement by Sn atoms. These extra Ge atoms were not involved in the crystallization process, proved by the Raman spectroscopy. The present study is fundamental for the design of advanced storage device based on PCMs.

In this paper, crystallization characteristics of amorphous Ge2Sb2Te5 (a-GST) films induced by a Gaussian picosecond laser with different laser fluence were carried out using transmission electron microscopy (TEM), Raman spectra and ab initio molecular dynamics (AIMD) simulations. TEM observations presented a solid-state phase transition with nanocrystalline microstructure at lower fluence, while a liquid-solid phase transition accompanied by an ingot-like crystalline microstructure was found at higher fluence, including a central coarse and an outer fine equiaxed regions as well as a columnar crystal region between them. In spite of the remarkable difference in microstructure, the composition of different regions kept constant from the Energy Dispersive Spectrometer (EDS) measurements. Different phase change behavior and laser fluence affected the shift of Raman peaks due to the phase change stress and thermal stress. A laser irradiation coupled AIMD simulation was then developed to study the preferential nucleation possibility. AIMD simulation results indicated that a thermal process in the central coarse equiaxed regions, with a higher cooling rate (10 k/ps) generated by the Gaussian picosecond laser irradiation, reduced the nucleation rate remarkably, causing crystal nucleus have enough space to grow up even to the micrometer scale. This is different from the morphology induced by nano- or femtosecond pulsed laser.

Reversible phase-change behaviors of Ge&ndash, Sb&ndash, Te based superlattices (GST-SL) were studied by ab initio molecular dynamics (AIMD) simulations based on three models containing Ge/Sb intermixing, namely the Petrov-mix, Ferro-mix, and Kooi-mix models. The flipping behavior of Sb atoms was found in all the three GST-SL models in the melting process. Among them the Kooi-mix model exhibited the best stability, and the analyses of bond length distribution and electron localization function provided a better explanation on the phase transition of GST-SL. Finally, we proposed a fast switching model for GST-SL based on Sb flipping.

Phase-change materials (PCMs) have been widely used in optical and electronic applications for their extraordinary properties. However, the procedure of fast transition about PCMs is still not clear for the time limit. Pulse laser, especially ultra-short pulse laser, is an excellent tool to study the crystallization characteristics of PCMs for its high heating rate. In this paper, picosecond pulsed laser was employed to study the crystallization of amorphous Ge2Sb2Te5 (a-GST) thin films via the evolution of morphology and microstructure. The threshold for inducing crystallization was 7.9 mJ/cm2 and amorphization occured at 17.2 mJ/cm2. With the aid of high-resolution transmission electron microscopy (HRTEM), the growth of grains were observed to own a preferable growth direction of [100]. The grain size and laser fluence showed an exponential relationship under the ps laser pulse, and the maximal grain reached to ~5 μm when approaching the melting point. The morphology and grain distribution of GST film under 18.8 mJ/cm2 indicated a solid-state phase transition. Besides, the matrix of a-GST film changed into crystalline state even though the surface melted into amorphous state when irradiated by high laser pulse. Finally, the reason for fast transition of a-GST film under ultra-short laser pulse was discussed in terms of heating rate and temperature. The present study is fundamental for the understanding of the fast phase transition of PCMs.

Heterostructural materials have the advantage of extreme low switching energy between states and hence are expected to be applied in photonic devices, whose optical performances are vital to explore in advance. In this paper, crystal structures of TiTe2/Sb2Te3 heterostructural films and their effects on optical properties were clarified from the aspects of in-plane strain, resonant bonding and charge redistribution by experiments and first principle simulations. Larger strain in Sb2Te3 sublayer tended to decrease reflectivity and refractive indexes, while huge resonant bonding effect was beneficial to improve the optical parameter deviations. Charge analyses showed that crystalline optical property variations were actually deriving from the electron redistribution differences especially near the heterostructural Te…Te gap, which also accounted for experimental reflectivity order. Finally, based on the resonant bond effects and surrounding electron density after stimuluses, five optical levels with identifiable optical contrasts (n and ΔR) were achieved in 1/2 model for uses. The present study sheds new light on optical properties of TiTe2/Sb2Te3 and paves the way for potential multi-state applications of heterostructure in photonic and storage devices.

Nano particle embedded thin film has great potential application in tuning the optical properties of phase change material. In this paper, we prepared GeTe nano particle embedded Cu composite thin film (GeTe@Cu) by magnetic co-sputtering GeTe and Cu targets. High-resolution transmission electron microscopy (HR-TEM) was used to characterize the local structure of the composite thin film and the GeTe nano particles. It was found that the composite thin film was constituted of net-like Cu-Cu bonds, Ge (Te)-Cu bonds as well as GeTe nano particles. Optical reflectivity of the composite thin film was also measured. Ab initio molecular dynamics (AIMD) simulations was employed to investigate the forming mechanism of GeTe nano particles and the local features in detail. Simulation results revealed that Ge-Te-Ge-Te four-fold ring promote the formation of GeTe atom cluster and large amount of free electrons from Cu atoms make the Ge-Te bonds stronger, in further leading to the formation of GeTe nano particles. These results in this paper paved the way for further research about multi-level optical storage of nano particles embedded phase change composite thin film.

The goal of this work will be to investigate the safety of ablating tissue with focused ultrasound adjacent to peripheral nerves or to nerve tracts in the brain. We propose experiments in which we ablate tissue adjacent to the sciatic nerve and the optic nerve/tract in the brain and then evaluate nerve function. These experiments are motivated by two promising targets for focused ultrasound treatment where critical nerve structures need to be protected: prostate cancer and brain tumors. If successful, this work will allow good surgical margins, thereby improving the effectiveness of focused ultrasound surgery and reducing local recurrence.

This paper presents a new approach to feature selection and classifcation based on support vector machine and hybrid artificial bee colony. The approach consists of two stages. At the first stage, this paper presented a hybrid artificial bee colony-based classifier model that combines artificial bee colony to improve classification accuracy with the most superior model parameter and features were selected from the original feature set. The classification accuracy and the feature subset provided by the SVM classifier are both considered to update the food source. Finally, the most superior features and optimal model parameter are fed into SVM to identify different class. The testing results verify the effectiveness of the method in extracting feature subset and pattern classification

In this paper, the effect of laser wavelength on the thermal behavior of amorphous Ge2Sb2Te5 (a-GST) films induced by a frequency-tripled picosecond laser was carried out using 3D surface profile, SEM, TEM and Raman measurement. Melting thresholds of a-GST films with different wavelengths of 355 nm (3.5 mJ/cm2), 532 nm (28 mJ/cm2) and 1064 nm (22.3 mJ/cm2) were obtained, respectively. It showed that with the increase of wavelength from 355 to 532 and 1064 nm, pit morphologies and crystallization degree didn’t follow a monotonous relation, which were mainly affected by melting threshold, optical penetration depth as well as photon energy. TEM images demonstrated that 532 nm laser-treated samples got more complete crystallization than those 355 nm laser treated. Besides, for the remarkable discrepancy in optical penetration depth among the three laser wavelengths, the crystallization process of a-GST at 355 and 532 nm wavelengths performed with a surficial heating mode, different from that at 1064 nm wavelength with a body heating mode. The present study paves the way to achieve the big-data storage using different wavelengths.

This paper carries out a questionnaire survey on 30 quality inspection institutions at the level of the Ministry of Agriculture, and based on systematic analysis, analyzes the causes of difficulties in personal submission of samples for inspection from six aspects in order to meet the real needs of personal submission of agricultural product samples for inspection under the new situation. In accordance with the actual situation of China's current regulatory system and quality control system, this paper sets forth the relevant recommendations to correctly guide the personal submission of samples for inspection and promote the development of quality inspection system.

The corrosion behavior of 316L stainless steel parts manufactured via selective laser melting (SLM) was investigated in this study. In order to explain the relationship of corrosion resistance and surface quality, several examples were made by SLM with different processing parameters (including laser power and scanning speed) and potentiodynamic polarization curve were measured. The results indicated that surface quality varied with different processing parameters and good surface quality contributed high corrosion resistance. In addition, when the laser power was 100 W while scanning speed was 1050 mm/s, the products possess high surface quality and corrosion resistance with corrosion potential −198 mV, corrosion current 0.556 μA.

This paper conducts a theoretical analysis on the pattern originality, pattern medium, performance and connotation, aiming to explore more reasonable laws for the interior-design pattern application.

Rapid identification and detection of oil spills is significant to maintain marine environment and ecosystems, so this paper mainly researches on the edge extraction of marine oil spill in SAR images and then presents an improved algorithm based on MRoA operator and MSP-RoA operator. Because speckle noise is a large problem in SAR images since even a homogeneous area has a statistical distribution with large standard deviation, speckle filtering is firstly studied. Compared with other algorithms, experiments are taken on the SAR images about oil spill accidents of oil tanker “Prestige” and “Hebei Spirit” by the proposed algorithm, which proved much better in reservation of information and boundary as well as correctness of oil spill extraction. By the consideration of applicability and practicability of the proposed algorithm, the SAR images for the experiment include different satellites such as ENVISAT and TERRASAR, and the mode are ASAR_WS and ScanSAR respectively, so the results are more persuasive and more exactly.

Oil spill accidents are seen relatively frequent and becomes a severe threat to coastal and marine ecosystems and water quality. Thus, active surveillance and rapid response to marine oil spills is important and essential to environment protection. So, this paper lays emphasis on the research of monitoring the marine oil spills for application by satellite remote sensing especially SAR. Imaging characteristics of satellites and image-forming principle of oil spill information in remote sensing images are analyzed at first. Then how to monitor the marine oil spills by satellite remote sensing and how to identify and detect marine oil spills information in SAR images are discussed mainly. Through the practical applications examples of the marine oil spill surveillance by satellite remote sensing in oil spill accidents of oil tanker “Hebei Spirit”, the method this paper proposed is proved to be very effectively and feasibly for the fast response and detection to oil spills especially in the waters near Bohai sea of China. Finally future development of marine oil spill surveillance is suggested with conclusion.

Based on image registration principle of the feature point, this article brings forward methods of a combination of Moravec and Forstner operator, extracts feature points in the base image making use of sequential detection algorithm from coarse to fine, and realizes automatic matching of the same name point in the pending registration images through the geometric distance constraint conditions. After the triangulation through the triangulation methods in this article, the images and the results by the second transformation method have similar performance, but in the process of registration it can save a lot of time and energy. Count the three aspects of information including entropy, degrees of spectral distortion and into-degrees of high-frequency information in the fused image. Of which entropy expresses the amount of images information. The value of entropy in the fused image is larger than the original panchromatic image and multi-spectral image, accounting for through the image fusion it indeed improves the information content of the image! In Shenzhen City Digital City project, the results by using of the method showed that the fusion effect is significantly higher than other traditional methods.

Solar Induced Convection Power Plant is a technology of new energy using. It has a very broad perspective. However, the efficiency of the technology not so acceptable. This paper focuses on improving the efficiency of the technology. The thermal physical properties of common glass, polycarbonate and polycarbonate with CO2 ware compared in this paper to study the superiority and scientificity of polycarbonate with CO2. The results show that, the heat transfer coefficient of polycarbonate with CO2 is the smallest so that it has the best effect of warm-keeping. and it can improve the efficiency of the system to large extent. According to the study, the polycarbonate with CO2 is the best one for solar radiation to go through and it is not easy for Far Infrared ray to do that. Base on the results and other advantages of the polycarbonate with CO2, we conclude that polycarbonate with CO2 is the best choice for the material of the slope solar collector cover.