Search

The pollution of heavy metals in irrigation water was related to the management-control of the risk of heavy metals in farmland and the safe production of crops. There were various sources of irrigation water in the suburb farmlands of Xijiang River. We investigated the sources and distribution characteristics of heavy metals in the irrigation water sources on a riverside and inside-dyke farmland of Xijiang River. According to sample test results, it was found that nearly 100% of heavy metals that we were concerned about were detected in the irrigation water sources in the study. The box plot showed that the average content of other elements ranged from 1.65 to 43.75 μg·L−1, and the average level of cadmium was 0.02 μg·L−1 in the studied area. According to quantitative evaluation index and analysis of distribution characteristics, most heavy metals were at relatively low concentration in the irrigation water sources, while mercury content was far greater than other elements, followed by arsenic. Arsenic and mercury had become increasingly prominent problems in local irrigation water sources. River quality was more likely to be affected by river water and agricultural activities, while groundwater quality was more likely to be affected by natural causes. According to single/comprehensive water-quality evaluations, the comprehensive water quality evaluation ranged from level I to level III, but the single-factor index evaluations of mercury in most water samples and arsenic in two groundwater samples were of ‘Inferior’ level. Attention should be paid to the monitoring of mercury and arsenic (in the groundwater) in the studied area. The disposal methods of farmland water inflow and drainage should be increased if necessary, and reducing the influence of human activities on the natural weathering and leaching of heavy metals was an effective measure to avoid risk of agricultural production. HIGHLIGHTS Nearly 100% of heavy metals that we were concerned about were detected in the irrigation water sources in the studied area in the early busy season of farming.; The studied area should reduce the frequency and use of groundwater irrigation.; The monitoring of mercury and arsenic should be strengthened immediately in the studied area.; Scientific research on the irrigation water sources in the early busy season of farming can react to the maximum anthropogenic influence on irrigation.

MicroRNAs (miRNAs) play vital roles in diverse biological processes, including in immune response. Blunt snout bream (Megalobrama amblycephala) is a prevalent and important commercial endemic freshwater fish species in China's intensive polyculture systems. To identify immune-related miRNAs of M. amblycephala, two small RNA (sRNA) libraries from immune tissues with or without lipopolysaccharide (LPS) stimulation were constructed and sequenced using the high-throughput sequencing technology. Totally, 16,425,543 and 15,076,813 raw reads, corresponding to 14,156,755 and 13,445,869 clean reads, were obtained in the normal and infected libraries, respectively. A total of 324 miRNAs, including 218 known miRNAs and 106 putative novel miRNAs were identified by bioinformatic analysis. We analyzed differentially expressed miRNAs between two libraries using pairwise comparison. 113 (34.88%) miRNAs were found to be significantly differentially expressed between two libraries, with 63 (55.75%) exhibiting elevated expression in LPS stimulation sample. Thereinto, a number of known miRNAs were identified immune-related. Real-time quantitative PCR (RT-qPCR) were implemented for 12 miRNAs of two samples, and agreement was confirmed between the sequencing and RT-qPCR data. Target genes likely regulated by these differentially expressed miRNAs were predicted using computational prediction. The functional annotation of target genes by Gene Ontology enrichment (GO) and Kyoto Encyclopedia of Genes and Genomes pathway analysis (KEGG) indicated that a majority of differential miRNAs might involved in immune response. To our knowledge, this is the first comprehensive study of miRNAs in response to LPS stimulation in M. amblycephala, even in fish. These results deepened our understanding of the role of miRNAs in the intricate host's immune system, and should be useful to develop new control strategies for host immune defense against various bacterial invasions in M. amblycephala.

C42H65Br2N4NiO8.5, monoclinic, P21/c (no. 14), a = 14.852(2) Å, b = 12.1965(18) Å, c = 14.166(2) Å, β = 117.755(1)°, V = 2270.8(6) Å3, Z = 2, Rgt(F) = 0.0449, wRref(F2) = 0.1276, T = 296(2) K.

C40H60Br2N4NiO8, triclinic, P1̄ (no. 2), a = 8.546(7) Å, b = 10.162(7) Å, c = 13.831(13) Å, α = 92.943(9)°, β = 101.096(8)°, γ = 111.710(5)°, V = 1085.1(15) Å3, Z = 1, Rgt(F) = 0.0317, wRref(F2) = 0.0905, T = 296(2) K.

Parametric module of gas blast soot blower distributor is created and friendly parametric dialog interface is developed by redevelopment of Pro/E using redevelopment tool Pro/Toolkit of Pro/E software system and Visual c++ 6.0 programming language. Parametric regeneration of distributor parts can be automatically realized and design efficiency of distributor improved by using the parametric module.

Attempt has been made to analyze applicability of different bridging relations based on the Mars Pathfinder data. The difference of aerodynamics predicted by seventeen gas/surface interaction models is investigated. Free molecular limit Kn effect on aerodynamics is analyzed lastly. The results show that bridging relations, gas/surface interaction models and free molecular limit Kn number influence aerodynamics seriously. Present data predicted by erflog bridging relation shows a good agreement with computational data predicted by Direct Simulation Monte Carlo(DSMC) method than others. Sin-squared bridging relation is more efficient than erf-log one with some accuracy loss which can be avoided most by adjusting free molecular limit Kn number. Erf-log bridging relations is not sensitive to free molecular limit Kn number, but that Kn number value should be above 50 to keep the accuracy in free molecular regime.

Based on the CAE analysis technology, possible defects of the sheets in the forming process are accurately simulated and predicted, and the method of eliminating defect is found. The results of the analysis not only improve the work efficiency, shorten the design and manufacturing cycle of the mold, but also provide a strong support for the design of mold and the development of the technology program. At the same time, the calculation results are consistent with the actual situation by using Dynaform software to simulate the results. The accuracy and the reliability of the calculation results by using the numerical simulation technology is validated.

Rolling mill is an important monomer production line equipment, and rolling mill main drive system is a core component. The design of rolling machine is important to improve the nature and service life of the rolling mill. This article through strip mill of the working parameters, and selected the transmission scheme to design the main components of the reducer. Through UG finished each parts 3d modeling and using the finite element software ANSYS reducer shell static and optimization analysis, and worked out the optimal design parameters of the shell.

Tourism has become the world's largest and highly competitive industry. Collaboration is a new strategy to compete in today's tourism industry, which provides a very efficient option with low cost, easy access and resources sharing for tourism industry players. This paper analyzes the concept of service flow and tourism service alliance. Based on Multiple Agent System (MAS) technology, a Service-flow Oriented Intelligent Collaboration Tourism Service System (SOICTSS) is designed to help today's tourism industry players to support cross-organization tourist service coordination and integration. A layered architecture of SOICTSS is proposed in this paper. Key Agents and its functions and collaborative service process in the SOICTSS are introduced.

IT governance planning is the first step of IT governance implementation. There are many related standards and frameworks for IT governance implementation, such as COBIT, ITIL and ISO 27002. In order to plan and design a proposal for IT governance implementation according to the company's IT governance requirements, “IT Process ontology” is introduced to model the knowledge of IT process, based on it, an IT process knowledge base and an IT governance implementation case base are created. A prototype decision supporting system for IT governance planning is designed and developed.

The n-type silicon integrated-back contact (IBC) solar cell has attracted much attention due to its high efficiency, whereas its performance is very sensitive to the wafer of low quality or the contamination during high temperature fabrication processing, which leads to low bulk lifetime τbulk. In order to clarify the influence of bulk lifetime on cell characteristics, two-dimensional (2D) TCAD simulation, combined with our experimental data, is used to simulate the cell performances, with the wafer thickness scaled down under various τbulk conditions. The modeling results show that for the IBC solar cell with high τbulk, (such as 1 ms–2 ms), its open-circuit voltage Voc almost remains unchanged, and the short-circuit current density Jsc monotonically decreases as the wafer thickness scales down. In comparison, for the solar cell with low τbulk (for instance, < 500 μs) wafer or the wafer contaminated during device processing, the Voc increases monotonically but the Jsc first increases to a maximum value and then drops off as the wafer's thickness decreases. A model combing the light absorption and the minority carrier diffusion is used to explain this phenomenon. The research results show that for the wafer with thinner thickness and high bulk lifetime, the good light trapping technology must be developed to offset the decrease in Jsc.