The first two Medium Earth Orbit(MEO) satellites of the third generation of Bei Dou satellite navigation System(BDS-3) were successfully launched on November 5, 2017. This historical launch starts the new era of the g...The first two Medium Earth Orbit(MEO) satellites of the third generation of Bei Dou satellite navigation System(BDS-3) were successfully launched on November 5, 2017. This historical launch starts the new era of the global navigation satellite system of Bei Dou. Before the first two satellites of BDS-3, a demonstration system for BDS-3 with five satellites,including two Inclined Geosynchronous Orbit satellites(IGSO) and three MEO satellites, was established between 2015 and2016 for testing the new payloads, new designed signals and new techniques. In the demonstration system, the new S frequency signal and satellite hydrogen clock as well as inter-satellite link(ISL) based on Ka-band signals with time-division multiple addresses(TDMA) were tested. This paper mainly analyzes the performances of the demonstration system, including the signalto-noise ratios, pseudorange errors and the multipath errors of the civilian signals of BDS-3. The qualities of signals in space,time synchronization and timing precision were tested as well. Most of the performances were compared with those of the regional Bei Dou satellite navigation system(BDS-2). At last, the performances of positioning, navigation and timing(PNT) of the future Bei Dou global system(BDS-3) were evaluated based on the signal quality of the present demonstration satellite system.展开更多
作者运用结构化工作分析问卷和行为事件访谈(Behavioral Event Interview,BEI)探讨了图书编辑的胜任特征模型。首先用职业信息网络系统(Occupational Information Network,O*NET)问卷进行工作分析,后进行专家访谈,确定初步的胜任特征编...作者运用结构化工作分析问卷和行为事件访谈(Behavioral Event Interview,BEI)探讨了图书编辑的胜任特征模型。首先用职业信息网络系统(Occupational Information Network,O*NET)问卷进行工作分析,后进行专家访谈,确定初步的胜任特征编码表。接着进行行为事件访谈,并根据编码表对访谈结果进行编码。最后通过对效标群体的分析,得到图书编辑的胜任特征,包括编辑策划、关注客户需求、市场意识、成就动机和问题敏感。展开更多
The technique of derivative constant energy synchronous fluorimetry was intro-duced in this article. For mixture of fluorene, acenaphthene, anthracene and perylene, thedetection limit is 2. 4, 17.1, 0.27, 0.043 ng/mL,...The technique of derivative constant energy synchronous fluorimetry was intro-duced in this article. For mixture of fluorene, acenaphthene, anthracene and perylene, thedetection limit is 2. 4, 17.1, 0.27, 0.043 ng/mL, respectively, when first-derivative con-stant energy synchronous fluorimetry is employed. The detectlon limit is 1. 5, 15. 0, 0.13,0. 022 ng/mL, respectively, when second-derivative constant energy synchronous fluorlme-try is employed. In the method, four compounds can be simultaneously determined withoutany mutual interference.展开更多
Infectious bursal disease virus (IBDV) was inactivated by two different chemicals—formaldehyde and binary ethylenimine (BEI). Formaldehyde was used at 0.1% and 0.2%, while BEI was used at concentrations of 0.001 and ...Infectious bursal disease virus (IBDV) was inactivated by two different chemicals—formaldehyde and binary ethylenimine (BEI). Formaldehyde was used at 0.1% and 0.2%, while BEI was used at concentrations of 0.001 and 0.002 mol/L. These four vaccines were tested for their efficiency in generating humoral immune response in different groups of broiler chicks. Both BEI-inactivated vaccines gave relatively higher antibody titers and were almost twice as efficient as formaldehyde-inactivated ones.展开更多
基金supported by National Key R&D Program of China (Grant Nos. 2016YFB0501700, 2016YFB0501701)National Natural Science Foundation of China (Grant No. 41374019)
文摘The first two Medium Earth Orbit(MEO) satellites of the third generation of Bei Dou satellite navigation System(BDS-3) were successfully launched on November 5, 2017. This historical launch starts the new era of the global navigation satellite system of Bei Dou. Before the first two satellites of BDS-3, a demonstration system for BDS-3 with five satellites,including two Inclined Geosynchronous Orbit satellites(IGSO) and three MEO satellites, was established between 2015 and2016 for testing the new payloads, new designed signals and new techniques. In the demonstration system, the new S frequency signal and satellite hydrogen clock as well as inter-satellite link(ISL) based on Ka-band signals with time-division multiple addresses(TDMA) were tested. This paper mainly analyzes the performances of the demonstration system, including the signalto-noise ratios, pseudorange errors and the multipath errors of the civilian signals of BDS-3. The qualities of signals in space,time synchronization and timing precision were tested as well. Most of the performances were compared with those of the regional Bei Dou satellite navigation system(BDS-2). At last, the performances of positioning, navigation and timing(PNT) of the future Bei Dou global system(BDS-3) were evaluated based on the signal quality of the present demonstration satellite system.
文摘作者运用结构化工作分析问卷和行为事件访谈(Behavioral Event Interview,BEI)探讨了图书编辑的胜任特征模型。首先用职业信息网络系统(Occupational Information Network,O*NET)问卷进行工作分析,后进行专家访谈,确定初步的胜任特征编码表。接着进行行为事件访谈,并根据编码表对访谈结果进行编码。最后通过对效标群体的分析,得到图书编辑的胜任特征,包括编辑策划、关注客户需求、市场意识、成就动机和问题敏感。
文摘The technique of derivative constant energy synchronous fluorimetry was intro-duced in this article. For mixture of fluorene, acenaphthene, anthracene and perylene, thedetection limit is 2. 4, 17.1, 0.27, 0.043 ng/mL, respectively, when first-derivative con-stant energy synchronous fluorimetry is employed. The detectlon limit is 1. 5, 15. 0, 0.13,0. 022 ng/mL, respectively, when second-derivative constant energy synchronous fluorlme-try is employed. In the method, four compounds can be simultaneously determined withoutany mutual interference.
基金Project (No. PSF/Res/P-AU/Bio (246)) supported by Pakistan Sci-ence Foundation (PSF)
文摘Infectious bursal disease virus (IBDV) was inactivated by two different chemicals—formaldehyde and binary ethylenimine (BEI). Formaldehyde was used at 0.1% and 0.2%, while BEI was used at concentrations of 0.001 and 0.002 mol/L. These four vaccines were tested for their efficiency in generating humoral immune response in different groups of broiler chicks. Both BEI-inactivated vaccines gave relatively higher antibody titers and were almost twice as efficient as formaldehyde-inactivated ones.
