152 research outputs found
Probing signatures of bounce inflation with current observations
The aim of this paper is to probe the features of the bouncing cosmology with
the current observational data. Basing on bounce inflation model, with high
derivative term, we propose a general parametrization of primordial power
spectrum which includes the typical bouncing parameters, such as bouncing
time-scale, and energy scale. By applying Markov Chain Monto Carlo analysis
with current data combination of Planck 2015, BAO and JLA, we report the
posterior probability distributions of the parameters. We find that, bouncing
models can well explain CMB observations, especially the deficit and
oscillation on large scale in TT power spectrum.Comment: 17 pages, 8 figure
Determining the Degree of [001] Preferred Growth of Ni(OH)\u3csub\u3e2\u3c/sub\u3e Nanoplates
Determining the degree of preferred growth of low-dimensional materials is of practical importance for the improvement of the synthesis methods and applications of low-dimensional materials. In this work, three different methods are used to analyze the degree of preferred growth of the Ni(OH)2 nanoplates synthesized without the use of a complex anion. The results suggest that the preferred growth degree of the Ni(OH)2 nanoplates calculated by the March parameter and the expression given by Zolotoyabko, which are based on the analysis and texture refinement of the X-ray diffraction pattern, are in good accordance with the results measured by SEM and TEM imaging. The method using the shape function of crystallites is not suitable for the determination of the preferred growth degree of the Ni(OH)2 nanoplates. The method using the March parameter and the expression given by Zolotoyabko can be extended to the analysis of block materials
Designing Proof of Transaction Puzzles for Cryptocurrency
One of the Bitcoin\u27s innovations is the Proof of Work puzzle (aka scratch-off puzzle) as a consensus protocol for anonymous networks without pre-established PKI. Bitcoins based on the Proof of Work puzzle have been harshly blamed today for problems such as energy wasted and not easily scalable. In this paper, we construct a novel Proof of Transaction(PoT) puzzle, and prove that PoT puzzle satisfies the basic construction conditions of scratch-off puzzle. We also show construction of PoTcoin as application. PoTcoin has many advantage but not limited as strengthening the network topology, promoting currency circulation, anti-outsourcing computing and environment-friendly
A Survey on Location-Driven Influence Maximization
Influence Maximization (IM), which aims to select a set of users from a
social network to maximize the expected number of influenced users, is an
evergreen hot research topic. Its research outcomes significantly impact
real-world applications such as business marketing. The booming location-based
network platforms of the last decade appeal to the researchers embedding the
location information into traditional IM research. In this survey, we provide a
comprehensive review of the existing location-driven IM studies from the
perspective of the following key aspects: (1) a review of the application
scenarios of these works, (2) the diffusion models to evaluate the influence
propagation, and (3) a comprehensive study of the approaches to deal with the
location-driven IM problems together with a particular focus on the
accelerating techniques. In the end, we draw prospects into the research
directions in future IM research
White Dwarfs with Infrared Excess from LAMOST Data Release 5
Infrared excess is an important probe of sub-stellar companions and/or debris
disks around white dwarfs (WDs). Such systems are still rare for in-depth
understanding of their formation and long-term evolution. One of the largest
spectroscopic surveys carried out by the Large sky Area Multi-Object fiber
Spectroscopic Telescope (LAMOST) recently released more than WDs, a
significant fraction of which have not undergone excess search. Here we present
cross-correlation of LAMOST DR5 WD catalog with the Pan-STARRS, SDSS, UKIDSS,
2MASS, and {\it WISE}. By performing SED (spectral energy distribution) fitting
for 846 WDs with detections, we identify 50 candidates with infrared
excess, including 7 candidate WD+M dwarf binaries, 31 candidate WD+brown dwarf
(BD) binaries and 12 candidate WD+dust disk systems. 8 of the dust disk systems
are our new identifications. Utilizing a systematic survey with accurate
stellar parameters derived from spectral fitting, our work is an important
addition to previous searches for infrared excess from SDSS and {\it Gaia} WDs,
and provides a significant () complement to current database of WDs
with candidate BD companions and dust disks. The frequencies of WD+BD binaries
and WD+dust disk systems are constrained to be and ,
respectively. The properties of candidate dust disk systems are discussed. All
of our candidates require follow-up observations for confirmation owing to
limited spatial resolution of {\it WISE}.Comment: 15 pages, 7 figures, 3 tables; accepted for publication in Ap
High-efficiency removal of Pb (II) and Cu (II) by amidoxime functionalized silica aerogels: Preparation, adsorption mechanisms and environmental impacts analysis
In this work, a novel adsorbent was evaluated for eliminating heavy metal ions from water. The cyano-functionalized silica aerogels (ANSA-X) were fabricated by functionalizing silica aerogel with 2-cyanoethyltrie-thoxysilane, and then further by the reaction with hydroxylamine hydrochloride to obtain amidoxime-functionalized silica aerogels (AOSA-X) with a large specific surface area. The FTIR and NMR analysis indicated that cyano was successfully transformed into amidoxime groups. Adsorption experiments showed the adsorption performed well with the Langmuir isotherm, and AOSA3 exhibited the optimum adsorption property with 598.05 mg/g for Pb (II) and 534.10 mg/g for Cu (II). The thermodynamic results indicated that spontaneous endothermic process was the nature of the adsorption. The adsorption rate of AOSA3 was above 86% after five successive adsorption–desorption cycles. XPS analysis and DFT calculations demonstrated that the N and O atoms participated in the chelating adsorption of Pb (II) and Cu (II), and the N atom on the amidoxime groups played a dominant role. Life Cycle Analysis (LCA) evaluated the environmental effect of the preparation of 1 kg AOSA3 adsorbent, identified the environmental factors with high environmental impact, proposed alternative solutions, proved the feasibility of preparing a novel high-efficiency amidoxime-based adsorbent, and provided a guideline for the sustainable mass production of AOSA3 adsorbent. In conclusion, AOSA3 demonstrated to have promising application perspectives in heavy metal effluent treatment
Trend and Cycle Analysis of Annual and Seasonal Precipitation in Liaoning, China
Annual and seasonal precipitation data for 49 meteorological stations over the period of 1960–2006 in Liaoning province were analyzed. Liaoning experienced province-wide decreases in precipitation over the 47-year period, with annual precipitation decreasing by 96% of the stations, followed by 92, 84, 63, and 27%, respectively, for summer, autumn, spring, and winter precipitation. Regional trend analysis confirmed the province-wide decrease, which was detected by the site-specific analysis, but a greater number of significant declines were found for annual, summer, and autumn precipitation for Liaoning province and for three of its four subregions. Four significant cycles with alternation patterns were detected mainly at the time scales of 3–5, 10-11, 20–23, and 31.2 years for each of the four subregions (Liaodong Peninsula, Northeastern Mountain, Western Highland, and Central Plain) and the entire Liaoning province, with the dominant periodicities being 10-11 years. The 10-11-year periodic variation of Liaoning annual precipitation was negatively associated with sunspot activity and positively associated with the East Asian Summer Monsoon (EASM) at the same time scale, while the 31.2-year periodic variation of Liaoning annual precipitation was positively correlated with both the EASM and ENSO activities at the 30–33-year time scale
- …