4,714 research outputs found

    Ultra-high energy cosmic rays threshold in Randers-Finsler space

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    Kinematics in Finsler space is used to study the propagation of ultra high energy cosmic rays particles through the cosmic microwave background radiation. We find that the GZK threshold is lifted dramatically in Randers-Finsler space. A tiny deformation of spacetime from Minkowskian to Finslerian allows more ultra-high energy cosmic rays particles arrive at the earth. It is suggested that the lower bound of particle mass is related with the negative second invariant speed in Randers-Finsler space

    Synthesis of molecularly imprinted polypyrrole/titanium dioxide nanocomposites and its selective photocatalytic degradation of rhodamine B under visible light irradiation

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    Highly selective molecularly imprinted nanocomposites MIPRhB-PPy/TiO2 were successfully prepared by surface molecular imprinting technique with rhodamine B (RhB) as template molecule. The prepared MIPRhB-PPy/TiO2 coated with a thin imprinted layer could respond to visible light. The static and dynamic binding experiments revealed that MIPRhB-PPy/TiO2 possessed strong affinity, high adsorption capacity and fast adsorption rate for RhB. The selectivity experiments indicated that MIPRhB-PPy/TiO2 had excellent recognition selectivity for RhB. Selective photocatalytic degradation experiments indicated that the apparent rate constant (k) for the photodegradation of RhB over MIPRhB-PPy/TiO2 is 0.0158 min–1, being 3.6 times of that over non-imprinted nanocomposites NIPRhB-PPy/TiO2 (0.0044 min–1). Compared with the NIPRhB-PPy/TiO2, MIPRhB-PPy/TiO2 showed higher photocatalytic selectivity toward RhB under visible light, which was attributed the introduction of the imprinted cavities on the surface of MIPRhB-PPy/TiO2. Moreover, MIPRhB-PPy/TiO2 exhibited high reusability and stability. The results indicate that molecularly imprinted nanocomposites MIPRhB-PPy/TiO2 have a promising perspective in industrial wastewater treatment

    Effective electro-optical modulation with high extinction ratio by a graphene-silicon microring resonator

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    Graphene opens up for novel optoelectronic applications thanks to its high carrier mobility, ultra-large absorption bandwidth, and extremely fast material response. In particular, the opportunity to control optoelectronic properties through tuning of Fermi level enables electro-optical modulation, optical-optical switching, and other optoelectronics applications. However, achieving a high modulation depth remains a challenge because of the modest graphene-light interaction in the graphene-silicon devices, typically, utilizing only a monolayer or few layers of graphene. Here, we comprehensively study the interaction between graphene and a microring resonator, and its influence on the optical modulation depth. We demonstrate graphene-silicon microring devices showing a high modulation depth of 12.5 dB with a relatively low bias voltage of 8.8 V. On-off electro-optical switching with an extinction ratio of 3.8 dB is successfully demonstrated by applying a square-waveform with a 4 V peak-to-peak voltage.Comment: 12 pages, including 7 figure

    Effects of Reentry Plasma Sheath on GPS Patch Antenna Polarization Property

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    A plasma sheath enveloping a reentry vehicle would affect performances of on-board antenna greatly, especially the navigation antennas. This paper studies the effects of reentry plasma sheath on a GPS right-hand circularly polarized (RHCP) patch antenna polarization property during a typical reentry process. Utilizing the algorithm of finite integration technique, the polarization characteristic of a GPS antenna coated by a plasma sheath is obtained. Results show that the GPS RHCP patch antenna radiation pattern distortions as well as polarization deteriorations exist during the entire reentry process, and the worst polarization mismatch loss between a GPS antenna and RHCP GPS signal is nearly 3 dB. This paper also indicates that measures should be taken to alleviate the plasma sheath for maintaining the GPS communication during the reentry process

    Fertilization shapes a well-organized community of bacterial decomposers for accelerated paddy straw degradation

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    \ua9 2018 The Author(s). Straw, mainly dry stalks of crops, is an agricultural byproduct. Its incorporation to soils via microbial redistribution is an environment-friendly way to increase fertility. Fertilization influences soil microorganisms and straw degradation. However, our up to date knowledge on the responses of the straw decomposers to fertilization remains elusive. To this end, inoculated with paddy soils with 26-year applications of chemical fertilizers, organic amendments or controls without fertilization, microcosms were anoxically incubated with 13C-labelled rice straw amendment. DNA-based stable isotope probing and molecular ecological network analysis were conducted to unravel how straw degrading bacterial species shift in responses to fertilizations, as well as evaluate what their roles/links in the microbiome are. It was found that only a small percentage of the community ecotypes was participating into straw degradation under both fertilizations. Fertilization, especially with organic amendments decreased the predominance of Firmicutes- and Acidobacteria-like straw decomposers but increased those of the copiotrophs, such as β-Proteobacteria and Bacteroidetes due to increased soil fertility. For the same reason, fertilization shifted the hub species towards those of high degrading potential and created a more stable and efficient microbial consortium. These findings indicate that fertilization shapes a well-organized community of decomposers for accelerated straw degradation

    Clinical data analysis of CDKs expression and prognosis in breast cancer

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    Objective: We investigated the expression of CDKs and prognosis in breast cancer. Materials and Methods: The Oncomine database examined CDK gene expressions in breast cancer. The prescient worth of CDKs in bosom malignant growth patients was analyzed utilizing the Kaplan-Meier Plotter. The expression changes of CDKs in tumor staging were analyzed in the GEPIA database. The role of CDKs in DNA replication and the cell cycle was analyzed utilizing the KEGG data set. Using the CBioPortal database, the association between CDKs gene expression and CDKs in breast cancer was investigated. The Encori database was used to study miRNAs that target CDKs. Results: Oncomine data showed that the expressions of CDK1, CDK5 and CDK20 in breast cancer patients were upregulated, while mRNA expression levels in CDK2 and CDK6 decreased, and CDK3, CDK4 and CDK7~19 were not expression data. Results from the GEPIA database revealed that the expression levels of CDK1, CDK2, CDK4, CDK5, CDK7, CDK8, and CDK20 were greater in breast cancer tissues than in normal tissues, and that CDK1 and CDK5 were significantly different, and the expression levels of CDK3 and CDK1 in the former were lower than those in the latter, while those in the latter did not change. Kaplan-Meier Plotter data showed that CDK1, CDK3, CDK4 and CDK20 were associated with a dismal prognosis in individuals with breast cancer, while mRNA level in CDK8 was associated with progression after survival. Conclusions: CDK1, CDK2c, CDK4, CDK5, CDK7, CDK8 and CDK20 can be used as molecular markers for breast cancer patients, or as potential targets for breast cancer therapy by targeting CDKs

    Potential impacts of climate extremes on snow under global warming conditions in the Mongolian Plateau

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    Purpose: The paper aims to investigate the possible changes in mean temperature in the Mongolian Plateau associated with the 1.5 and 2°C global warming targets and how snow changes in the Mongolian Plateau when the mean global warming is well below 2°C or limited to 1.5°C. Design/methodology/approach: In total, 30 model simulations of consecutive temperature and precipitation days from Coupled Model Inter-comparison Project Phase 5 (CMIP5) are assessed in comparison with the 111 meteorological monitoring stations from 1961–2005. Multi-model ensemble and model relative error were used to evaluate the performance of CMIP5 models. Slope and the Mann–Kendall test were used to analyze the magnitude of the trends and evaluate the significance of trends of snow depth (SD) from 1981 to 2014 in the Mongolian Plateau. Findings: Some models perform well, even better than the majority (80%) of the models over the Mongolian Plateau, particularly HadGEM2-CC, CMCC-CM, BNU-ESM and GFDL-ESM2M, which simulate best in consecutive dry days (CDD), consecutive wet days (CWD), cold spell duration indicator (CSDI) and warm spell duration indicator (WSDI), respectively. Emphasis zones of WSDI on SD were deeply analysed in the 1.5 and 2 °C global warming period above pre-industrial conditions, because it alone has a significant negative relation with SD among the four indices. It is warmer than before in the Mongolian Plateau, particularly in the southern part of the Mongolian Plateau, indicating less SD. Originality/value: Providing climate extremes and SD data sets with different spatial-temporal scales over the Mongolian Plateau. Zoning SD potential risk areas and proposing adaptations to promote regional sustainable development

    Magnetothermoelectric transport in modulated and unmodulated graphene

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    We draw motivation from recent experimental studies and present a comprehensive study of magnetothermoelectric transport in a graphene monolayer within the linear response regime. We employ the modified Kubo formalism developed for thermal transport in a magnetic field. Thermopower as well as thermal conductivity as a function of the gate voltage of a graphene monolayer in the presence of a magnetic field perpendicular to the graphene plane is determined for low magnetic fields (~1 Tesla) as well as high fields (~8 Tesla). We include the effects of screened charged impurities on thermal transport. We find good, qualitative as well as quantitative, agreement with recent experimental work on the subject. In addition, in order to analyze the effects of modulation, which can be induced by various means, on the thermal transport in graphene, we evaluate the thermal transport coefficients for a graphene monolayer subjected to a periodic electric modulation in a magnetic field. The results are presented as a function of the magnetic field and the gate voltage.Comment: 14 pages, 8 figure
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