Axionlike-particle generation by laser-plasma interaction

Axion, a hypothetical particle that is crucial to quantum chromodynamics and dark matter theory, has not yet been found in any experiment. With the improvement of laser technique, much stronger quasi-static electric and magnetic fields can be created in laboratory using laser-plasma interaction. In this article, we discuss the feasibility of axion or axionlike-particle's exploring experiments using planar and cylindrically symmetric laser-plasma fields as backgrounds while probing with an ultrafast superstrong optical laser or x-ray free-electron laser with high photon number. Compared to classical magnet design, the axion source in laser-plasma interaction trades the accumulating length for the source's interacting strength. Besides, a structured field in the plasma creates a tunable transverse profile of the interaction and improves the signal-noise ratio via the mechanisms such as phase-matching. The mass of axion discussed in this article ranges from 1 \textmu eV to 1 eV. Some simple schemes and estimations of axion production and probe's polarization rotation are given, which reveals the possibility of future laser-plasma axion source in laboratory.Comment: 24 pages, 5 figure

Analysis on the characteristics of geological disasters and effectiveness of early warning duiring heavy rainfall on “23•7” in Beijing

Extreme rainfall is often accompanied by mass geological disasters, which seriously endangers the safety of people 's lives and property in prone areas and affects the healthy development of the economy and society. Summarizing and analyzing the time-space distribution characteristics of geological disasters due to extreme rainfall and the effectiveness of early warning is of great significance for improving the comprehensive defense ability against geological disasters. Taking the sudden geological disasters caused by “23•7” heavy rainfall in 2023 as the research object, based on the refined precipitation data from the Beijing sudden geological disaster monitoring and early warning system, the time-space distribution characteristics of “23•7” heavy rainfall and the development and distribution characteristics of geological disasters were analyzed, and the early warning effect of geological disasters was discussed. The results show that the“23•7”heavy rainfall has the characteristics such as a large total amount, strong rainfall, long duration and wide range, and the disasters due to extreme rainfall have the characteristics of group occurrence. The multi-dimensional early warning of geological disaster classification has achieved remarkable results and has achieved the goal of zero casualties due to geological disasters under extreme weather conditions. The research results can provide a reference for actively preventing and scientifically responding to extreme rainfall geological disasters

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Escape of lattice water in potassium iron hexacyanoferrate for cyclic optimization in potassium‐ion batteries

Abstract Potassium iron hexacyanoferrate (Prussian blue [PB]) is a very competitive cathode for potassium‐ion batteries due to its 3D robust open framework. However, [Fe(CN)6]4− vacancies and lattice water existed in PB lattices aggravate electrochemical performances. Herein, PBs with different content of vacancies and lattice water are obtained under two synthesis temperatures of 0°C and 25°C. Although K1.36Fe[Fe(CN)6]0.74·0.48H2O (PB0) exhibits an outstanding rate capability compared with K1.43Fe[Fe(CN)6]0.94·0.42H2O (PB25), PB25 with less defects shows a lower polarization and superior stability than PB0 during the cycle. Fourier transform infrared (FTIR) spectra results show that lattice water can escape from PB lattices during the cycle, which enhances the diffusion of K+ kinetically in the PB structure. Benefited from this phenomenon, the diffusion coefficient of K+ in vacancy‐less PB25 reaches 10−8 in two reaction platforms. As potassium‐ion battery cathodes, PB25 displays higher capacity retention of 86.5% over 1000 cycles at 5 C than PB0 with 20.1% capacity retention over 600 cycles. This study provides a new understanding of [Fe(CN)6]4− vacancy and lattice water behavior in K‐containing PB structure

Stability analysis of large-scale stope using stage subsequent filling mining method in Sijiaying iron mine

To improve mining production capacity, a stage subsequent filling mining (SSFM) method is employed for Sijiaying iron mine. The height of the stage stope is approximately 100 m. As there are farmlands and villages on the surface of the mine, the surface deformation should be controlled when the ore is mined out for the purpose of stope stability and minimizing surface subsidence. In this paper, according to the site-specific geological conditions, the self-stability of the stage-filling body was analyzed, and the failure mechanism of backfilling body was defined. Thus the relationship between the exposed height of filling body and the required strength was obtained. Next, the stability of backfilling body and the characteristics of surface subsidence due to mining of −450 m level were analyzed using physical modeling. Finally, a three-dimensional numerical model was established using FLAC3D, with which the surface subsidence and the stability of stope were achieved. The results show that the stope basically remains stable during the two-step recovery process. The maximum magnitude of the incline is 10.99 mm/m, a little larger than the permissible value of 10 mm/m, and the horizontal deformation is 5.9 mm/m, approaching the critical value of 6.0 mm/m, suggesting that the mine design is feasible for safety mining

Weibel instability mediated laser hole boring and ion acceleration in an electrostatic shock

We show that generation of strong magnetic field filaments due to Weibel instability accompanies the hole-boring ion acceleration by a circularly polarised laser pulse. The magnetic field confines energetic protons accelerated from hole boring in high density collimated jets. A part of energetic protons are reaccelerated by the electric field and focused by the magnetic field generated from the jets. As a result, highly collimated proton jets with high cutoff energy can be produced

Geo-spatial Cognition on Human's Social Activity Space Based on Multi-scale Grids

Widely applied location aware devices, including mobile phones and GPS receivers, have provided great convenience for collecting large volume individuals' geographical information. The researches on the human's society behavior space has attracts an increasingly number of researchers. In our research, based on location-based Flickr data From 2004 to May, 2014 in China, we choose five levels of spatial grids to form the multi-scale frame for investigate the correlation between the scale and the geo-spatial cognition on human's social activity space. The HT-index is selected as the fractal inspired by Alexander to estimate the maturity of the society activity on different scales. The results indicate that that the scale characteristics are related to the spatial cognition to a certain extent. It is favorable to use the spatial grid as a tool to control scales for geo-spatial cognition on human's social activity space

Triggering factor analysis of deposit slope under rainfall infiltration based on laboratory experiments

The identification and analysis of the deposit slope stability is the focus of geological disaster prevention and control. Taking dense-fine grained slopes and loose gravel slopes as examples, a series of flume tests under rainfall infiltration were carried out. The effects of density, material composition, slope angle and vegetation coverage on slope stability and rainfall threshold were systematically analyzed. The results show that under rainfall infiltration, the dense-fine grained slope with uniform material composition and high density was more stable, resulting in a higher rainfall threshold and a lower catastrophability. The slope with non-uniformmaterial composition and loose gravel was more likely to fail than the slope with dense fine particles. The influence of the stone content on the stability of the slope is greater than that of the slope gradient. The critical rainfall of landslides increases first and then decreases with an increasing vegetation coverage; that is, when rainfall infiltration causes the slope soil to be supersaturated, the higher vegetation coverage will trigger the whole deformation of slope and vegetation due to the strong development of vegetation roots, which increases the catastrophability of the slope.The research results can provide a theoretical basis for the instability mechanism and stability evaluation of deposit slopes

Visuospatial Bias in Children with Autism Spectrum Disorder: Evidence from Line Bisection Tasks

Previous studies have found reduced leftward bias of facial processing in individuals with Autism Spectrum Disorder (ASD). However, it is not clear whether they manifest a leftward bias in general visual processing. To shed light on this issue, the current study used the manual line bisection task to assess children 5 to 15 years of age with ASD as well as typically developing (TD) children. Results showed that children with ASD, similar to TD children, demonstrate a leftward bias in general visual processing, especially for bisecting long lines (&gt;= 80 mm). In both groups, participant performance in line bisection was affected by the hand used, the length of the line, the cueing symbol, and the location of the symbol. The ASD group showed a rightward bias when bisecting short lines (30 mm) with their left hands, which slightly differed from the TD group. These results indicate that while ASD individuals and TD individuals share a similar leftward bias in general visual processing, when using their left hands to bisect short lines, ASD individuals may show an atypical bias pattern.</p

Research on Real Estate Unit Unified Identifier Model Based on GeoSOT Code

It is a spatial uncertainty for existing real estate unit identifier. So, in order to reflect the spatial position based on real estate unit identifier directly, it proposes a real estate unit code model based on GeoSOT code, encoding method, and the spatial location information transformation scheme between this model and spatial location, after we study the existing real estate unit identifier model. The test shows that it is very useful and direct to show the spatial location with the real estate unit identifier based on GeoSOT code