Research on Big Data Technology System of Smart City

With the coming of the age of intelligence, the new information and communication technology represented by big data technology brings new perspectives and foundations to solve the traditional city problems. Based on the actual needs of urban smart development and urban governance, big data should be excavated and processed reasonably and effectively, and the supporting role of big data for urban development should be studied, and a more practical strategic development path has been proposed. Based on the research of the current smart big data technology system, this article analyzes facts, pinpoints difficulties, and proposes solutions to problems, and contributes to the modernization of the national governance system and governance capabilities

The radiation emitted from axion dark matter in a homogeneous magnetic field, and possibilities for detection

We study the direct radiation excited by oscillating axion (or axion-like particle) dark matter in a homogenous magnetic field and its detection scheme. We concretely derive the analytical expression of the axion-induced radiated power for a cylindrical uniform magnetic field. In the long wave limit, the radiation power is proportional to the square of the B-field volume and the axion mass $m_a$, whereas it oscillate as approaching the short wave limit and the peak powers are proportional to the side area of the cylindrical magnetic field and $m_a^{-2}$. The maximum power locates at mass $m_a\sim\frac{3\pi}{4R}$ for fixed radius $R$. Based on this characteristic of the power, we discuss a scheme to detect the axions in the mass range $1-10^4$\,neV, where four detectors of different bandwidths surround the B-field. The expected sensitivity for $m_a\lesssim1\,\mu$eV under typical-parameter values can far exceed the existing constraints.Comment: 10 pages, 9 figures, comments welcome

Methyl 2-[2-(benzyl­oxycarbonyl­amino)­propan-2-yl]-5-hy­droxy-6-meth­oxy­pyrimidine-4-carboxyl­ate

In the title compound, C18H21N3O6, a pyrimidine derivative, the dihedral angle between the benzene and pyrimidine rings is 52.26 (12)°. The carboxyl­ate unit is twisted with respect to the pyrimidine ring, making a dihedral angle of 12.33 (7)°. In the crystal, mol­ecules are linked by a pair of O—H⋯O hydrogen bonds, forming an inversion dimer. The dimers are stacked into columns along the b axis through weak C—H⋯O inter­actions

The First Insight into the Tissue Specific Taxus Transcriptome via Illumina Second Generation Sequencing

The First Insight into the Tissue Specific Taxus Transcriptome via Illumina Second Generation SequencingBackground: Illumina second generation sequencing is now an efficient route for generating enormous sequence collections that represent expressed genes and quantitate expression level. Taxus is a world-wide endangered gymnosperm genus and forms an important anti-cancer medicinal resource, but the large and complex genomes of Taxus have hindered the development of genomic resources. The research of its tissue-specific transcriptome is absent. There is also no study concerning the association between the plant transcriptome and metabolome with respect to the plant tissue type

Failure probability estimation of long pipeline

It is well known that, for the majority of pressurized pipelines, both the load and the resistance parameters show evident uncertainty, and a probabilistic approach should be applied to assess their behaviors. Concerning reliability estimation of passive components such as pressure vessel and pipeline, there are two kinds of approaches – direct estimation using statistics of historical failure event data, and indirect estimation using probabilistic analysis of the failure phenomena of consideration. The direct estimation method can be validated relatively easily. However, it suffers statistical uncertainty due to scarce data. Indirect estimation method relies on the statistics of material property and those of environment load which are more readily available. As to systems composed of passive components, statistical dependence among component failures is a complex issue that cannot be ignored in reliability estimation

Accuracy modeling and analysis for a lock-or-release mechanism of the Chinese Space Station Microgravity Platform

With development of Chinese space science and technology, plenty of microgravity experiments will be conducted in the Chinese Space Station to be built, and therefore demand for high-precision electromechanical equipment increases substantially. In this paper, a comprehensive accuracy analysis of a new type of auto lock-or-release (L/R) mechanism, which is applied in the Space Station Microgravity Platform (SSMP), is implemented. Firstly, two models (vector analysis model and vector differential model) are, therefore, proposed to analyze output errors of the mechanism. Due to transmission errors from the transmission chain of the gear mechanism, influence factors on axial errors of lead screws are analyzed using design of experiment (DOE) for factor sensitivities. It shows that manufacturing tolerances of the lead screw is the dominant factor. Then, verification of the two proposed accuracy models is comparatively implemented through Monte Carlo (MC) simulation and DOE. Using the present accuracy model, location errors of the lead screw throughout the mechanism's working stroke are illustrated, where the non-synchronous error of the mechanism is particularly discussed. A linear relation between the variance of the non-synchronous error and that of the structural error is established, followed by analyzing influence factors on the non-synchronous error

Increased concentrations of soluble B7-H3 and interleukin 36 in bronchoalveolar lavage fluid of Children with Mycoplasma pneumoniae pneumonia

Supporting data. (XLS 58 kb

Grouting solidification technology for fractured soft coal seams and its application in coalbed methane (coal mine gas) extraction

This article presents an effective method for improving the structure and performance of coal rock masses, thereby facilitating coalbed methane extraction—the grouting solidification technique. A systematic review is conducted on grouting solidification materials, process methods, evaluation techniques, and other related aspects. In conclusion, it is emphasized that the grouting solidification technique requires further refinement in its system, and its continued significance in the dynamically evolving energy and coal industry is underscored. This is crucial for ensuring the efficient development and sustainable utilization of coal and coalbed methane resources