采用反相高效液相色谱(RP-HPLC)与质谱(MS)联用技术对固相法化学合成七肽(H2N-PFNSLAI-COOH,M r 760.9)时出现的消旋产物进行了分析。根据弱疏水性合成七肽粗品特性,提出了充分利用吸附和分配双重保留机制的“早期吸附”概念,以此优化...采用反相高效液相色谱(RP-HPLC)与质谱(MS)联用技术对固相法化学合成七肽(H2N-PFNSLAI-COOH,M r 760.9)时出现的消旋产物进行了分析。根据弱疏水性合成七肽粗品特性,提出了充分利用吸附和分配双重保留机制的“早期吸附”概念,以此优化色谱条件得到4个峰形良好的色谱峰;质谱分析表明:4谱峰具有相同的m/z761.5[M+H]+值,对每一消旋产物进行在线多肽测序,并利用串联质谱(MSn)谱图叠加的方法,得到b轴和y轴两套片段信息,成功确定了合成七肽的4个消旋产物。展开更多
As an active microwave remote sensing imaging sensor, Synthetic Aperture Radar(SAR) plays an important role in earth observation. Here we establish a SAR system based on the platform of the moon. This will aid large-s...As an active microwave remote sensing imaging sensor, Synthetic Aperture Radar(SAR) plays an important role in earth observation. Here we establish a SAR system based on the platform of the moon. This will aid large-scale, constant, and long-term dynamic Earth observations to better meet the needs of global change research and to complement the space borne and airborne earth observations. Lunar-based SAR systems have the characteristics of high resolution and wide swath width. The swath width could be thousands of kilometers in the stripe mode and it could cover 40% of earth's surface with 10 meters or even higher spatial resolution in the scanning mode. Using the simplified observation model, here we quantitatively analyze the spatial resolution and coverage area of lunar-based SAR and simulate the observation on the Qinghai-Tibet plateau and the Amazon plain. The results show that this system could provide near 100% daily coverage of the Qinghai-Tibet plateau, whereas 40% to 70% daily coverage of the Amazon plain. Lunar-based SAR could provide large-scale, long-term and stable time series data in order to support future research of global change.展开更多
文摘采用反相高效液相色谱(RP-HPLC)与质谱(MS)联用技术对固相法化学合成七肽(H2N-PFNSLAI-COOH,M r 760.9)时出现的消旋产物进行了分析。根据弱疏水性合成七肽粗品特性,提出了充分利用吸附和分配双重保留机制的“早期吸附”概念,以此优化色谱条件得到4个峰形良好的色谱峰;质谱分析表明:4谱峰具有相同的m/z761.5[M+H]+值,对每一消旋产物进行在线多肽测序,并利用串联质谱(MSn)谱图叠加的方法,得到b轴和y轴两套片段信息,成功确定了合成七肽的4个消旋产物。
基金supported by National Basic Research Program of China (Grant No. 2009CB723906)National Natural Science Foundation of China (Grant No. 60972141)
文摘As an active microwave remote sensing imaging sensor, Synthetic Aperture Radar(SAR) plays an important role in earth observation. Here we establish a SAR system based on the platform of the moon. This will aid large-scale, constant, and long-term dynamic Earth observations to better meet the needs of global change research and to complement the space borne and airborne earth observations. Lunar-based SAR systems have the characteristics of high resolution and wide swath width. The swath width could be thousands of kilometers in the stripe mode and it could cover 40% of earth's surface with 10 meters or even higher spatial resolution in the scanning mode. Using the simplified observation model, here we quantitatively analyze the spatial resolution and coverage area of lunar-based SAR and simulate the observation on the Qinghai-Tibet plateau and the Amazon plain. The results show that this system could provide near 100% daily coverage of the Qinghai-Tibet plateau, whereas 40% to 70% daily coverage of the Amazon plain. Lunar-based SAR could provide large-scale, long-term and stable time series data in order to support future research of global change.
