Results of our investigation showed that occurrence frequency of Pi2 over a 24 hour period undergoes seasonal variations in time coincidence with foF2. In the winter months, at sunrise and sunset (when foF2gradients a...Results of our investigation showed that occurrence frequency of Pi2 over a 24 hour period undergoes seasonal variations in time coincidence with foF2. In the winter months, at sunrise and sunset (when foF2gradients are the largest) the observation probability of these oscillations is minimal. At periods of summer solstice when the F2-layer persists almost round the clock, no effect of Pi2 pulsation attenuation is observed at sunrise and sunset. The pulsation amplitudes behave in a similar manner. Results of this study suggest the conclusion that the propagation of signal from the Pi2 sourse into the mid-latitudes, and also the parameters of these pulsations are essentially affected by electron density in the ionospheric F2-layer.展开更多
[Objective] The paper was to improve the blast resistance of insect-resistant transgenic rice. [Method] The Japonica rice variety Jikang10, a new transgenic variety with exogenous insect-resistant gene Cry1C, was used...[Objective] The paper was to improve the blast resistance of insect-resistant transgenic rice. [Method] The Japonica rice variety Jikang10, a new transgenic variety with exogenous insect-resistant gene Cry1C, was used as the receptor, and Kongyu 131, a traditional breeding variety with broad-spectrum high blast resistance genes Pi1 and Pi2, was used as the donor to breeding new rice varieties. The genes were polymerized by hybridization and multi-generation backcrossing, and the offspring of each generation was screened by molecular marker assisted selection, field identification of multi-resistance against insect pests and diseases and agronomic trait selection. [Result] Four lines SK01, SK02, SK03 and SK04 with better resistances to insect pests and blast and outstanding agronomic traits in field were selected. [Conclusion] The results will lay foundations for breeding new multi-resistance rice varieties in Huanghuai rice region.展开更多
There is understanding to date that Pi2 pulsations have two sources. One source is a high-latitude one and is due to fluctuations of electro jet parameters. The other source is a mid-latitude one and is driven by a gl...There is understanding to date that Pi2 pulsations have two sources. One source is a high-latitude one and is due to fluctuations of electro jet parameters. The other source is a mid-latitude one and is driven by a global mode excited in the Earths plasmasphere. There is experimental evidence that in the nearequatorial regions the character of Pi2 excitation is different from high and mid-latitudes. In this connection,we investigated the amplitude-spectral-polarization characteristics of Pi2 pulsations using the date from nearequatorial Chinese stations. The detected regularities in the excitation of near-equatorial Pi2 pulsations are used in the discussion of the possible physical mechanism that is responsible for the generation of these pulsations.展开更多
In this paper Pi2 pulsations at Zhongshan Station of Antarctica are analyzed from October 1 - 31, 1996. Their characteristics e. g. occurrence frequency,frequency, and polarization are studied. The characteristics of ...In this paper Pi2 pulsations at Zhongshan Station of Antarctica are analyzed from October 1 - 31, 1996. Their characteristics e. g. occurrence frequency,frequency, and polarization are studied. The characteristics of Pi2 pulsations are summerized as follows: (1 ) Pi2 pulsations at Zhongshan Station usually take place from 2000 MLT to 0200 MLT; the main frequencies are between 6. 79 mHz and 13. 58mHZ; (2 ) Pi2 pulsations with low frequencies are dominent. The range of main frequencies becomes narrow at midnight; (3) The Polarization of Pi2 pulsations are almost linear; (4) About the orientation of major axes the NW-SE direction is dominent before 2200 MLT and NE-SW is dominent after 2200 MLT. The generation mechanism of Pi2 pulsations at Zhongshan Station is discussed theoretically.展开更多
基金Supported by the China-Russia Joint Research Center on Space Weather,Chinese Academy of Sciences
文摘Results of our investigation showed that occurrence frequency of Pi2 over a 24 hour period undergoes seasonal variations in time coincidence with foF2. In the winter months, at sunrise and sunset (when foF2gradients are the largest) the observation probability of these oscillations is minimal. At periods of summer solstice when the F2-layer persists almost round the clock, no effect of Pi2 pulsation attenuation is observed at sunrise and sunset. The pulsation amplitudes behave in a similar manner. Results of this study suggest the conclusion that the propagation of signal from the Pi2 sourse into the mid-latitudes, and also the parameters of these pulsations are essentially affected by electron density in the ionospheric F2-layer.
基金Supported by The Agricultural Seed Improvement Project of Shandong (2019LZGC017, 2019LZGC003)Agricultural Industry Research System (Rice) Project of Shandong Province (SDAIT-17-03)The Agricultural and Technology Innovation Project of Shandong Academy of Agricultural Sciences(CXGC2021A30)。
文摘[Objective] The paper was to improve the blast resistance of insect-resistant transgenic rice. [Method] The Japonica rice variety Jikang10, a new transgenic variety with exogenous insect-resistant gene Cry1C, was used as the receptor, and Kongyu 131, a traditional breeding variety with broad-spectrum high blast resistance genes Pi1 and Pi2, was used as the donor to breeding new rice varieties. The genes were polymerized by hybridization and multi-generation backcrossing, and the offspring of each generation was screened by molecular marker assisted selection, field identification of multi-resistance against insect pests and diseases and agronomic trait selection. [Result] Four lines SK01, SK02, SK03 and SK04 with better resistances to insect pests and blast and outstanding agronomic traits in field were selected. [Conclusion] The results will lay foundations for breeding new multi-resistance rice varieties in Huanghuai rice region.
基金Supported by the China-Russia Joint Research Center on Space Weather,Chinese Academy of Sciences
文摘There is understanding to date that Pi2 pulsations have two sources. One source is a high-latitude one and is due to fluctuations of electro jet parameters. The other source is a mid-latitude one and is driven by a global mode excited in the Earths plasmasphere. There is experimental evidence that in the nearequatorial regions the character of Pi2 excitation is different from high and mid-latitudes. In this connection,we investigated the amplitude-spectral-polarization characteristics of Pi2 pulsations using the date from nearequatorial Chinese stations. The detected regularities in the excitation of near-equatorial Pi2 pulsations are used in the discussion of the possible physical mechanism that is responsible for the generation of these pulsations.
文摘In this paper Pi2 pulsations at Zhongshan Station of Antarctica are analyzed from October 1 - 31, 1996. Their characteristics e. g. occurrence frequency,frequency, and polarization are studied. The characteristics of Pi2 pulsations are summerized as follows: (1 ) Pi2 pulsations at Zhongshan Station usually take place from 2000 MLT to 0200 MLT; the main frequencies are between 6. 79 mHz and 13. 58mHZ; (2 ) Pi2 pulsations with low frequencies are dominent. The range of main frequencies becomes narrow at midnight; (3) The Polarization of Pi2 pulsations are almost linear; (4) About the orientation of major axes the NW-SE direction is dominent before 2200 MLT and NE-SW is dominent after 2200 MLT. The generation mechanism of Pi2 pulsations at Zhongshan Station is discussed theoretically.
