Study of factors influencing the occurrence rate of 60 Hz power line radiation in the topside ionosphere:A systematic survey using the CSES satellite

We analyze the topside ionosphere power line radiation(PLR)at 60 Hz over the US using electric field data collected by CSES satellite between January 2019 and December 2022.The study aimed to further investigate the month-to-month variation characteristic of PLR occurrence rate observed by satellite and its several influencing factors,including solar radiation,lightning activity,and try to clarify the influence of electricity consumption.The results show that the solar radiation(solar zenith angle and F10.7)plays a major role in the variation of the PLR occurrence rate,and that there is no direct connection with the number of lightning.For the relationship between PLR occurrence rate and electricity consumption,the low occurrence rate associated with decreased weekend electricity consumption was not observed in the US.However,there is a significant difference in PLR occurrence rate between the East and West Coasts of the US at the same latitude during the same time period,suggesting that the significant difference in PLR occurrence rate is caused by the significant difference in electricity consumption between the two coasts.After excluding the effect of solar radiation on PLR occurrence rate,we concluded that only a significant difference in regional electricity consumption could lead to a corresponding change in PLR occurrence rate detected by the Low-Earth-Orbit satellite.Finally,we also found there is seasonal variation in the diurnal differences of the PLR occurrence rate caused by seasonal variation of the lower ionosphere.

Random field characteristics of earthquake occurrence and test of earthquake occurrence rate

The random field characteristics of earthquake occurrence is studied, the random field of earthquake occurrence is defined according to basic concepts of random field, and expectations of the random field are discussed. It is proved that this random field is inhomogeneous. The average of the random field can not be estimated from the spatial-distribution average. So, in order to overcome this shortcoming, and assistant random field is introduced.This assistant random filed is homogenous and ergodic. The average of this random field can be evaluated from spatial-distribution average. On the basis of these results, earthquake occurrence rate adopted by Chinese Seismic Zoning Map(1990 version) are tested by using recent 15 years data and recent 50 years data.

A novel real-time RT-PCR with TaqM an-MGB probes and its application in detecting BVDV infections in dairy farms

A real-time RT-PCR assay using Taq Man-MGB probes was developed to detect and type the bovine viral diarrhea virus（BVDV） in cattle.Universal primers and Taq Man-MGB probes were designed from the 5′-untranslated region of known pestiviral sequences.Prior to optimizing the assay, c RNAs were transcribed in vitro from the BVDV 1 and BVDV 2 RTPCR products to make standard curves.The detection limit of the assay was 1.72×102 copies for BVDV 1 and 2.14×102copies for BVDV 2.The specificity of the assay evaluated on several BVDV strains including bovine herpesvirus 1（BHV 1）, foot and mouth disease virus（FMDV） and several classical swine fever virus（CSFV） strains showed specific detection of the positive virus over 40 cycles.The assay was highly reproducible with the coefficient of variance ranging from 1.04 to 1.33% for BVDV 1 and from 0.83 to 1.48% for BVDV 2, respectively.Using this method, we tested a total of 2 327 cattle from three dairy farms for the presence of BVDV persistently infected（PI） animals.In this assay, each RT-PCR template contained a mixture of ten samples from different animals.The occurrence rate of PI cattle in three farms ranging from 0.9 to 2.54% could represent partly the PI rates in cattle farm in China.In conclusion, using our real-time PCR assay, we could effectively detect and type BVDV and identify PI cattle in a rapid and cost-effective manner.

Influence of statistical time range on estimating seismicity parameters

The influence of non-uniqueness in selecting statistical time ranges on seismicity parameters of b value and annual mean occurrence rate ν4 is widely analyzed and studied. The studied result states that the influence of statistical time range on the b value is generally smaller than on the annual mean rate. Owing to the exponentially functional relation between the annual mean rate and b value, the variation of b value by varying statistical time range brings about decrease or increase in the annual mean rates of each magnitude interval with power progression law. These results will exert a synthetic effect on seismic safety evaluation results in various regions in our country.

Research on the Seismic Activity of the Lower Yangtze River-South Yellow Sea Seismic Zone

The Lower Yangtze River-South Yellow Sea Seismic Zone,located at the southeast of the Northern China Seismic Zone, characterized by moderate-strong earthquakes, is an intensive earthquake zone,which is controlled by a series of faults within the Lower Yangtze River-South Yellow Sea Seismic Zone. This article counts and calculates the bvalue,V 4 and energy density value of medium-small earthquakes by taking full advantage of the latest data from regional seismic stations,reviews data of historical earthquakes and seismic structure,and discusses the relationship between spatial distribution of the b-value, historical strong earthquakes and spatial distribution of energy density of medium-small earthquakes,and further investigates the seismic activity of the Lower Yangtze River- South Yellow Sea Seismic Zone. This article obtains seismic activity parameters of the Lower Yangtze River-South Yellow Sea Seismic Zone as calculation parameters for probabilistic seismic hazard analysis,and discusses the trend of this seismic zone in the next one hundred years and deduces the potential seismic hazard region within this seismic zone,which provides references and methods for long-term prediction on seismic activity. The research results are significant to seismic zoning, seismic safety evaluation of engineering sites and long-term prediction of seismic activity.

Reliability Analysis of Repairable Systems Using Stochastic Point Processes

In order to analyze the failure data from repairable systems, the homogeneous Poisson process (HPP) is usually used. In general, HPP cannot be applied to analyze the entire life cycle of a complex, re-pairable system because the rate of occurrence of failures (ROCOF) of the system changes over time rather than remains stable. However, from a practical point of view, it is always preferred to apply the simplest method to address problems and to obtain useful practical results. Therefore, we attempted to use the HPP model to analyze the failure data from real repairable systems. A graphic method and the Laplace test were also used in the analysis. Results of numerical applications show that the HPP model may be a useful tool for the entire life cycle of repairable systems.