95 research outputs found

    Homoepitaxial regrowth habits of ZnO nanowire arrays

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    Synthetic regrowth of ZnO nanowires [NWs] under a similar chemical vapor transport and condensation [CVTC] process can produce abundant ZnO nanostructures which are not possible by a single CVTC step. In this work, we report three different regrowth modes of ZnO NWs: axial growth, radial growth, and both directions. The different growth modes seem to be determined by the properties of initial ZnO NW templates. By varying the growth parameters in the first-step CVTC process, ZnO nanostructures (e.g., nanoantenna) with drastically different morphologies can be obtained with distinct photoluminescence properties. The results have implications in guiding the rational synthesis of various ZnO NW heterostructures

    Unification of the Negative Electrocaloric Effect in Bi\u3csub\u3e1/2\u3c/sub\u3eNa\u3csub\u3e1/2\u3c/sub\u3eTiO\u3csub\u3e3\u3c/sub\u3e-BaTiO\u3csub\u3e3\u3c/sub\u3e Solid Solutions by Ba\u3csub\u3e1/2\u3c/sub\u3eSr\u3csub\u3e1/2\u3c/sub\u3eTiO\u3csub\u3e3\u3c/sub\u3e Doping

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    The microscopic mechanisms of the negative electrocaloric effect (ECE) of the single-phase (1āˆ’x)(0.94Bi1/2Na1/2TiO3-0.06BaTiO3)-xBa1/2Sr1/2TiO3 (BNT-BT-BST) perovskite solid solutions fabricated via the sol-gel technique are explored in this study. Dielectric and mechanical relaxation analyses are employed to investigate the ferroelectric and structural transitions of the samples. The electrocaloric properties of the samples were measured by thermodynamics Maxwell relations. The difference between the depolarization temperature (Td) and the maximum dielectric constant temperature (Tm) was found to decrease with increasing BST content. Doping with BST stabilized the ferroelectric phase along with unifying the EC temperature changes (Ī”T) to only negative values. The origin of the uniform negative ECE of BNT-BT-BST is discussed

    Image encryption for Offshore wind power based on 2D-LCLM and Zhou Yi Eight Trigrams

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    Offshore wind power is an important part of the new power system, due to the complex and changing situation at ocean, its normal operation and maintenance cannot be done without information such as images, therefore, it is especially important to transmit the correct image in the process of information transmission. In this paper, we propose a new encryption algorithm for offshore wind power based on two-dimensional lagged complex logistic mapping (2D-LCLM) and Zhou Yi Eight Trigrams. Firstly, the initial value of the 2D-LCLM is constructed by the Sha-256 to associate the 2D-LCLM with the plaintext. Secondly, a new encryption rule is proposed from the Zhou Yi Eight Trigrams to obfuscate the pixel values and generate the round key. Then, 2D-LCLM is combined with the Zigzag to form an S-box. Finally, the simulation experiment of the algorithm is accomplished. The experimental results demonstrate that the algorithm can resistant common attacks and has prefect encryption performance.Comment: accepted by Int. J. of Bio-Inspired Computatio

    Application of a new Structural Joint Inversion Approach to Teleseismic and Gravity Data from Mt.Vesuvius, Italy

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    A 3-D joint inversion of seismic and gravimetric data is performed to re-investigate the subsurface structure of Mt. Vesuvius (Italy) utilizing an improved joint inversion method. The aim is to derive models of the 3D distribution of velocity and density perturbations that are consistent with both data sets and with local velocity models. Mt. Vesuvius is a strato volcano located within a graben (Campania Plain) formed in Plio-Pleistocene. Campania Plain is bordered by mostly Mesozoic carbonaceous rocks. Mt. Vesuvius is the southernmost and the youngest of a group of Pleistocene volcanoes, three of which (Ischia, Campi Flegrei and Mt. Vesuvius) have erupted in historical times. The most recent eruption of Mt. Vesuvius occurred in 1944 and since then the volcanic activity has been characterized by moderate low magnitude seismicity and low temperature fumaroles at the summit crater. We modified the coupling mechanism between velocity and density models in the JI-3D optimized joint inversion method (Jordan and Achauer, 1999). This method was designed to provide stable and high resolution results and involves iterative optimized parameterization, 3D ray tracing, and the incorporation of a priori information. The coupling of the velocity and density models, vital to the joint inversion, is based on a cross-gradient approach (e.g. Gallardo and Meju, 2004), which has been proven to work very well in a variety of cases involving seismic, magnetic, CSEM, MT and gravity data sets. We implemented the cross-gradient coupling for our 3-D irregular adaptive grid parameterization. In contrast to conventional joint inversion methods this approach encourages structural similarities in the models and does not rely on predefined relationships between velocity and density parameters. As a consequence, the resulting velocity-density relations are not contaminated by a priori assumptions and can be utilized to derive rock physical parameters. We apply this method to data from the TomoVes project (Gasparini et al. 1998), combining seismics and Bouguer gravity and local high resolution velocity models as a priori information. The starting models for the joint inversion are derived by separate inversions of the individual data sets. We show 3D distributions of velocity perturbations and density variations from the joint inversion of teleseismic relative traveltimes and Bouguer anomaly data with the aim of extracting further information about the physical status of the volcano- tectonic system

    Panax Quinquefolium Saponins Attenuate Myocardial Dysfunction Induced by Chronic Ischemia

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    Background/Aims: Previous studies in rat models of myocardial ischemia showed that Panax quinquefolium saponins (PQS) could attenuate ischemic/reperfusion injury, increase vessel density and improve cardiac function. In the current study, we examined whether PQS could attenuate myocardial dysfunction in a swine model of chronic myocardial ischemia (CMI). Methods: CMI was established in Bama mini-pigs by placing amroid constrictor on the left anterior descending artery (LAD). Starting from 2 months after the surgery, pigs randomly received PQS (30 mg/kg/day), atorvastatin (1.5 mg/kg/day), or no drug for one month (n=6). A group of pigs receiving sham surgery was included as an additional control. Glucose utilization was assessed with positron emission tomography-computer tomography (PET-CT). Cardiac function was assessed with echocardiography. Myocyte size, nuclear density, and arteriolar density were examined in tissue section obtained from the ischemia area. Potential molecular targets of PQS were identified using proteomic analysis with isobaric tags for relative and absolute quantitation (iTARQ) and network pharmacology. Results: In comparison to the sham controls, pigs implanted with ameroid constrictor had decreased ventricular wall motion, left ventricular ejection fraction (LVEF), and glucose utilization. PQS significantly increased cardiac function and glucose utilization. Arteriole density and myocyte nuclear density were increased. Myocyte diameter was decreased. PQS also attenuated the CMI-induced change of protein expression profile. The effects of atorvastatin were generally similar to that of PQS. However, PQS attenuated the reduction of left ventricular systolic WT induced by CMI more robustly than atorvastatin. Conclusion: The results from the current study supports the use of PQS in patients with coronary artery disease

    The Chinese pine genome and methylome unveil key features of conifer evolution

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    Conifers dominate the world's forest ecosystems and are the most widely planted tree species. Their giant and complex genomes present great challenges for assembling a complete reference genome for evolutionary and genomic studies. We present a 25.4-Gb chromosome-level assembly of Chinese pine (Pinus tabuliformis) and revealed that its genome size is mostly attributable to huge intergenic regions and long introns with high transposable element (TE) content. Large genes with long introns exhibited higher expressions levels. Despite a lack of recent whole-genome duplication, 91.2% of genes were duplicated through dispersed duplication, and expanded gene families are mainly related to stress responses, which may underpin conifers' adaptation, particularly in cold and/or arid conditions. The reproductive regulation network is distinct compared with angiosperms. Slow removal of TEs with high-level methylation may have contributed to genomic expansion. This study provides insights into conifer evolution and resources for advancing research on conifer adaptation and development

    Mate Selection Power and Female Marital Mortality Differential in China during Transition

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    Thesis (Master's)--University of Washington, 2021This paper documents a marked sex difference of the mortality differential between the never married and the married population in China 1990. Different from existing studies made in Western societies, the female never married group is found to experience an atypically larger mortality differential from the married than do males in China. Further, the marital mortality differential of females is found to be greater in contexts of high socioeconomic background. We explain the observed abnormality with theories of mate selection power. Under the Chinese patrilineal family system, females are in part selected into marriage by health criteria and males by resources criteria. In high socioeconomic places, malesā€™ resources produce larger mate selection power, resulting in stronger selectivity on femalesā€™ health

    A Fully Coupled Hydromechanical Model for CO2 Sequestration in Coal Seam: the Roles of Multiphase Flow and Gas Dynamic Diffusion on Fluid Transfer and Coal Behavior

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    CO2 sequestration in coal seam has proved to be an effective way for reducing air pollution caused by greenhouse gases. A study on the rules of fluid transfer and reliability of CO2 storage during gas injection is necessary for the engineering application. However, the clarification of multifield coupling in long-term CO2 sequestration is the difficulty to solve the aforementioned problem. Previous investigations on the coupled model for CO2 storage in coal seam were not exactly comprehensive; for example, the multiphase flow in the fracture and the nonlinear behavior of gas diffusion were generally neglected. In this paper, a new multistage pore model of the coal matrix and the corresponding dynamic diffusion model were adopted. Meanwhile, the CO2-induced coal softening and the CO2-water two-phase flow in coal fracture were also taken into account. Subsequently, all the mentioned mechanisms and interactions were embedded into the coupled hydromechanical model, and this new fully coupled model was well verified by a set of experimental data. Additionally, through the model application for long-term CO2 sequestration, we found that the stored CO2 molecules are mainly in an adsorbed state at the early injection stage, while with the continuous injection of gas, the stored CO2 molecules are mainly in a free state. Finally, the roles of multiphase flow and gas dynamic diffusion on fluid transfer and coal behavior were analyzed. The results showed that the impact of multiphase flow is principally embodied in the area adjacent to the injection well and the coal seam with lower initial water saturation is more reliable for CO2 sequestration, while the impact of gas dynamic diffusion is principally embodied in the area far away from the injection well, and it is safer for CO2 sequestration in coal seam with greater attenuation coefficient of CO2 diffusion
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