Because ambient seismic noise provides estimated Green’s function （EGF） between two sites with high accuracy, Rayleigh wave propagation along the path connecting the two sites is well resolved. Therefore, earthquak...Because ambient seismic noise provides estimated Green’s function （EGF） between two sites with high accuracy, Rayleigh wave propagation along the path connecting the two sites is well resolved. Therefore, earthquakes which are close to one seismic station can be well located with calibration extracting from EGF. We test two algorithms in locating the 1998 Zhangbei earthquake, one algorithm is waveform-based, and the other is traveltime-based. We first compute EGF between station ZHB （a station about 40 km away from the epicenter） and five IC/IRIS stations. With the waveform-based approach, we calculate 1D synthetic single-force Green’s functions between ZHB and other four stations, and obtain traveltime corrections by correlating synthetic Green’s functions with EGFs in period band of 10–30 s. Then we locate the earthquake by minimizing the differential travel times between observed earthquake waveform and the 1D synthetic earthquake waveforms computed with focal mechanism provided by Global CMT after traveltime correction from EGFs. This waveform-based approach yields a location which error is about 13 km away from the location observed with InSAR. With the traveltime-based approach, we begin with measuring group velocity from EGFs as well as group arrival time on observed earthquake waveforms, and then locate the earthquake by minimizing the difference between observed group arrival time and arrival time measured on EGFs. This traveltime-based approach yields accuracy of 3 km, Therefore it is feasible to achieve GT5 （ground truth location with accuracy 5 km） with ambient seismic noises. The less accuracy of the waveform-based approach was mainly caused by uncertainty of focal mechanism.展开更多
To further understand the generation and development of coinfection of Marek＇s disease virus （MDV） and reticuloendotheliosis virus （REV） in broiler breeders, and then find the method and optimal time of different...To further understand the generation and development of coinfection of Marek＇s disease virus （MDV） and reticuloendotheliosis virus （REV） in broiler breeders, and then find the method and optimal time of differential diagnosis for complex clinic multiple infection, the authors studied the pathohistological changes, apoptosis, immunohistochemistry （immunofluorescence）, and ultrastructure of tumor tissues of broiler breeders inoculated with MDV and REV. The study showed that proliferation of small lymphocytes was seen in the main organs at the age of 1 week, then immature lymphocytes, all kinds of lymphocytes, primitive reticulum cells, and Marek＇s disease cells （MDCs） were observed at 2-9 weeks. Apoptosis of lymphocytes could not be seen until the age of 10 weeks in the immune system. Immunohistochemistry detection showed that the positive signs of MDV and REV antigen were observed in the main organs at 2 weeks of age. Multi-morphology lymphocytes, MDV, and REV, mitotic figures and apoptosis of lymphocytes were observed with the help of transmission electron microscopy. MDV cooperating with REV promotes the course of disease of coinfection. Differential diagnosis can be done by immunohistochemistry in the early stage （before 2 weeks）, and histopathology in the late stage （post 4 weeks）. MDCs, primitive reticulum cells, immature lymphocytes, and two kinds of virions can serve as a basis for bistopathology differential diagnosis.展开更多
An experiment was conducted to examine probable impact of location and handling on the fungi commonly associated with rotting watermelon (Citrullus lanatus). The rotting watermelon samples were obtained from two vendo...An experiment was conducted to examine probable impact of location and handling on the fungi commonly associated with rotting watermelon (Citrullus lanatus). The rotting watermelon samples were obtained from two vendors each from five different markets (Bodija, Sango, Mokola, Eleyele, Agbowo and Ojoo) in Ibadan, Oyo state. They were placed in different sterile sample bags which were labeled appropriately before bringing them to the Pathology Laboratory, Department of Botany, University of Ibadan. Isolation of fungi from the rotting samples was carried out using pour plate method on acidified Potato Dextrose Agar (APDA). Pathogenicity test was also conducted for the isolated fungi. All experiments were done in duplicates and all plates were incubated at 25°C ± 2°C for 7 days. Pure cultures were obtained and identified and each isolated fungus was recorded as 1 which means present and 0 which means absent. The data obtained were analyzed using SAS version 9.3 at p ≤ 0.05. A total of three fungi were isolated viz., Aspergillus flavus, Saccharomyces cerevisae and Aspergillus niger. Occurrence of A. niger and A. flavus in samples obtained from Bodija, Mokola, Sango and Ojoo markets were significantly (P ≤ 0.05) higher than those from the other two markets. Occurrence of S. cerevisae in samples obtained from Bodija and Mokola markets were significantly (P ≤ 0.05) higher than those from the other three markets. Location had significant impact on the occurrence of isolated fungi in the rotting watermelons. However, handling by vendors had no significant impact on occurrence of the isolated fungi. Vendors and consumers are advised to be mindful of place of purchase and to also maintain good general hygiene before consumption.展开更多
With dense seismic arrays and advanced imaging methods, regional three-dimensional （3D） Earth models have become more accurate. It is now increasingly feasible and advantageous to use a 3D Earth model to better loca...With dense seismic arrays and advanced imaging methods, regional three-dimensional （3D） Earth models have become more accurate. It is now increasingly feasible and advantageous to use a 3D Earth model to better locate earthquakes and invert their source mechanisms by fitting synthetics to observed waveforms. In this study, we develop an approach to determine both the earthquake location and source mechanism from waveform information. The observed waveforms are filtered in different frequency bands and separated into windows for the individual phases. Instead of picking the arrival times, the traveltime differences are measured by cross-correlation between synthetic waveforms based on the 3D Earth model and observed waveforms. The earthquake location is determined by minimizing the cross-correlation traveltime differences. We then fix the horizontal location of the earthquake and perform a grid search in depth to determine the source mechanism at each point by fitting the synthetic and observed waveforms. This new method is verified by a synthetic test with noise added to the synthetic waveforms and a realistic station distribution. We apply this method to a series of Mw3.4-5.6 earthquakes in the Longmenshan fault （LMSF） zone, a region with rugged topography between the eastern margin of the Tibetan plateau and the western part of the Sichuan basin. The results show that our solutions result in improved waveform fits compared to the source parameters from the catalogs we used and the location can be better constrained than the amplitude-only approach. Furthermore, the source solutions with realistic topography provide a better fit to the observed waveforms than those without the topography, indicating the need to take the topography into account in regions with rugged topography.展开更多
1 GoTa System Features andLocation Service1.1 GoTaGoTa, the abbreviation of“Global OpenTrunking Architecture”, is anew-generation digital trunkingcommunication system based on theCDMA2000 1x technology. It makes use...1 GoTa System Features andLocation Service1.1 GoTaGoTa, the abbreviation of“Global OpenTrunking Architecture”, is anew-generation digital trunkingcommunication system based on theCDMA2000 1x technology. It makes use of manyadvantages of the CDMA technology and makesimprovement and optimization for the digitaltrunking communication system. It cansimultaneously realize multipte services including展开更多
The goal of the research is to develop a methodology to minimize the public’s exposure to harmful emissions from coal power plants while maintaining minimal operational costs related to electric distribution losses a...The goal of the research is to develop a methodology to minimize the public’s exposure to harmful emissions from coal power plants while maintaining minimal operational costs related to electric distribution losses and coal logistics. The objective is achieved by combining EPA Screen3, ISC3 and Japanese METI-LIS model equations with minimum spanning tree (MST) algorithm. Prim’s MST algorithm is used to simulate an electric distribution system and coal transportation pathways. The model can detect emission interaction with another source and estimate the ground level concentrations of emissions up to distances of 25 kilometers. During a grid search, the algorithm helps determine a candidate location, for a new coal power plant, that would minimize the operational cost while ensuring emission exposure is below the EPA/NIOSH thresholds. The proposed methodology has been coded in form of a location analysis simulation. An exhaustive search strategy delivers a final candidate location for a new coal power plant to ensure minimum operational costs as compared to the random or greedy search strategy. The simulation provides a tool to industrial zone planners, environmental engineers, and stakeholders in coal-based power generation. Using operational and emissions perspectives, the tool helps ascertain a list of compromise locations for a new coal power plant facility.展开更多
针对高压直流输电线路故障定位中存在的输电线路长、故障概率大、测距精度不高以及故障波形含有噪声等问题,提出了VMD分解与广义S变换结合的高压直流输电线路故障测距算法。首先通过变分模态分解(Variational Model Decomposition,VMD)...针对高压直流输电线路故障定位中存在的输电线路长、故障概率大、测距精度不高以及故障波形含有噪声等问题,提出了VMD分解与广义S变换结合的高压直流输电线路故障测距算法。首先通过变分模态分解(Variational Model Decomposition,VMD)对含噪声的行波信号进行VMD分解,滤去噪声并获得最优模态分量。然后采用广义S变换(Generalized S-transform,GST)计算最优模态分量,生成高时间分辨率S矩阵。并选取S矩阵中的高频分量,识别该频率分量的波形突变点,从而获取故障初始行波到达时刻。最后通过测距公式获得故障距离。PSCAD/EMTDC仿真表明,所提方法受过渡电阻影响很小,不同故障距离的测距精度很高。经过现场故障行波数据的验证,可以实现在线路范围内快速准确的故障定位。展开更多
基金partially supported by the research grants from Spark Program of Earthquake Sciences(XH213703Y)National Institute of Natural Hazards,Ministry of Emergency Management of China(No.ZDJ2020-09 and No.ZDJ2019-16).
基金supported by Chinese Acadmy of Sciences Fund(No.KCZX-YW-116-1)Joint Seismological Science Fundation of China (Nos.20080878 and 200708035)
文摘Because ambient seismic noise provides estimated Green’s function （EGF） between two sites with high accuracy, Rayleigh wave propagation along the path connecting the two sites is well resolved. Therefore, earthquakes which are close to one seismic station can be well located with calibration extracting from EGF. We test two algorithms in locating the 1998 Zhangbei earthquake, one algorithm is waveform-based, and the other is traveltime-based. We first compute EGF between station ZHB （a station about 40 km away from the epicenter） and five IC/IRIS stations. With the waveform-based approach, we calculate 1D synthetic single-force Green’s functions between ZHB and other four stations, and obtain traveltime corrections by correlating synthetic Green’s functions with EGFs in period band of 10–30 s. Then we locate the earthquake by minimizing the differential travel times between observed earthquake waveform and the 1D synthetic earthquake waveforms computed with focal mechanism provided by Global CMT after traveltime correction from EGFs. This waveform-based approach yields a location which error is about 13 km away from the location observed with InSAR. With the traveltime-based approach, we begin with measuring group velocity from EGFs as well as group arrival time on observed earthquake waveforms, and then locate the earthquake by minimizing the difference between observed group arrival time and arrival time measured on EGFs. This traveltime-based approach yields accuracy of 3 km, Therefore it is feasible to achieve GT5 （ground truth location with accuracy 5 km） with ambient seismic noises. The less accuracy of the waveform-based approach was mainly caused by uncertainty of focal mechanism.
基金supported by grants from the National Science Foundation for Post-Doctoral of China(2005038258)
文摘To further understand the generation and development of coinfection of Marek＇s disease virus （MDV） and reticuloendotheliosis virus （REV） in broiler breeders, and then find the method and optimal time of differential diagnosis for complex clinic multiple infection, the authors studied the pathohistological changes, apoptosis, immunohistochemistry （immunofluorescence）, and ultrastructure of tumor tissues of broiler breeders inoculated with MDV and REV. The study showed that proliferation of small lymphocytes was seen in the main organs at the age of 1 week, then immature lymphocytes, all kinds of lymphocytes, primitive reticulum cells, and Marek＇s disease cells （MDCs） were observed at 2-9 weeks. Apoptosis of lymphocytes could not be seen until the age of 10 weeks in the immune system. Immunohistochemistry detection showed that the positive signs of MDV and REV antigen were observed in the main organs at 2 weeks of age. Multi-morphology lymphocytes, MDV, and REV, mitotic figures and apoptosis of lymphocytes were observed with the help of transmission electron microscopy. MDV cooperating with REV promotes the course of disease of coinfection. Differential diagnosis can be done by immunohistochemistry in the early stage （before 2 weeks）, and histopathology in the late stage （post 4 weeks）. MDCs, primitive reticulum cells, immature lymphocytes, and two kinds of virions can serve as a basis for bistopathology differential diagnosis.
文摘An experiment was conducted to examine probable impact of location and handling on the fungi commonly associated with rotting watermelon (Citrullus lanatus). The rotting watermelon samples were obtained from two vendors each from five different markets (Bodija, Sango, Mokola, Eleyele, Agbowo and Ojoo) in Ibadan, Oyo state. They were placed in different sterile sample bags which were labeled appropriately before bringing them to the Pathology Laboratory, Department of Botany, University of Ibadan. Isolation of fungi from the rotting samples was carried out using pour plate method on acidified Potato Dextrose Agar (APDA). Pathogenicity test was also conducted for the isolated fungi. All experiments were done in duplicates and all plates were incubated at 25°C ± 2°C for 7 days. Pure cultures were obtained and identified and each isolated fungus was recorded as 1 which means present and 0 which means absent. The data obtained were analyzed using SAS version 9.3 at p ≤ 0.05. A total of three fungi were isolated viz., Aspergillus flavus, Saccharomyces cerevisae and Aspergillus niger. Occurrence of A. niger and A. flavus in samples obtained from Bodija, Mokola, Sango and Ojoo markets were significantly (P ≤ 0.05) higher than those from the other two markets. Occurrence of S. cerevisae in samples obtained from Bodija and Mokola markets were significantly (P ≤ 0.05) higher than those from the other three markets. Location had significant impact on the occurrence of isolated fungi in the rotting watermelons. However, handling by vendors had no significant impact on occurrence of the isolated fungi. Vendors and consumers are advised to be mindful of place of purchase and to also maintain good general hygiene before consumption.
基金supported by National Natural Science Foundation of China (Grants No.41374056)the Fundamental Research Funds for the Central Universities (WK2080000053)
文摘With dense seismic arrays and advanced imaging methods, regional three-dimensional （3D） Earth models have become more accurate. It is now increasingly feasible and advantageous to use a 3D Earth model to better locate earthquakes and invert their source mechanisms by fitting synthetics to observed waveforms. In this study, we develop an approach to determine both the earthquake location and source mechanism from waveform information. The observed waveforms are filtered in different frequency bands and separated into windows for the individual phases. Instead of picking the arrival times, the traveltime differences are measured by cross-correlation between synthetic waveforms based on the 3D Earth model and observed waveforms. The earthquake location is determined by minimizing the cross-correlation traveltime differences. We then fix the horizontal location of the earthquake and perform a grid search in depth to determine the source mechanism at each point by fitting the synthetic and observed waveforms. This new method is verified by a synthetic test with noise added to the synthetic waveforms and a realistic station distribution. We apply this method to a series of Mw3.4-5.6 earthquakes in the Longmenshan fault （LMSF） zone, a region with rugged topography between the eastern margin of the Tibetan plateau and the western part of the Sichuan basin. The results show that our solutions result in improved waveform fits compared to the source parameters from the catalogs we used and the location can be better constrained than the amplitude-only approach. Furthermore, the source solutions with realistic topography provide a better fit to the observed waveforms than those without the topography, indicating the need to take the topography into account in regions with rugged topography.
文摘1 GoTa System Features andLocation Service1.1 GoTaGoTa, the abbreviation of“Global OpenTrunking Architecture”, is anew-generation digital trunkingcommunication system based on theCDMA2000 1x technology. It makes use of manyadvantages of the CDMA technology and makesimprovement and optimization for the digitaltrunking communication system. It cansimultaneously realize multipte services including
文摘The goal of the research is to develop a methodology to minimize the public’s exposure to harmful emissions from coal power plants while maintaining minimal operational costs related to electric distribution losses and coal logistics. The objective is achieved by combining EPA Screen3, ISC3 and Japanese METI-LIS model equations with minimum spanning tree (MST) algorithm. Prim’s MST algorithm is used to simulate an electric distribution system and coal transportation pathways. The model can detect emission interaction with another source and estimate the ground level concentrations of emissions up to distances of 25 kilometers. During a grid search, the algorithm helps determine a candidate location, for a new coal power plant, that would minimize the operational cost while ensuring emission exposure is below the EPA/NIOSH thresholds. The proposed methodology has been coded in form of a location analysis simulation. An exhaustive search strategy delivers a final candidate location for a new coal power plant to ensure minimum operational costs as compared to the random or greedy search strategy. The simulation provides a tool to industrial zone planners, environmental engineers, and stakeholders in coal-based power generation. Using operational and emissions perspectives, the tool helps ascertain a list of compromise locations for a new coal power plant facility.
文摘针对高压直流输电线路故障定位中存在的输电线路长、故障概率大、测距精度不高以及故障波形含有噪声等问题,提出了VMD分解与广义S变换结合的高压直流输电线路故障测距算法。首先通过变分模态分解(Variational Model Decomposition,VMD)对含噪声的行波信号进行VMD分解,滤去噪声并获得最优模态分量。然后采用广义S变换(Generalized S-transform,GST)计算最优模态分量,生成高时间分辨率S矩阵。并选取S矩阵中的高频分量,识别该频率分量的波形突变点,从而获取故障初始行波到达时刻。最后通过测距公式获得故障距离。PSCAD/EMTDC仿真表明,所提方法受过渡电阻影响很小,不同故障距离的测距精度很高。经过现场故障行波数据的验证,可以实现在线路范围内快速准确的故障定位。
