In western China, most petroliferous basins are superposed due to their multi-periodic tectonic evolution, and the mechanisms of petroleum migration and accumulation are so complex that much more sophis- ticated metho...In western China, most petroliferous basins are superposed due to their multi-periodic tectonic evolution, and the mechanisms of petroleum migration and accumulation are so complex that much more sophis- ticated methodologies are necessary for depiction of these mechanisms and identification of petroleum occurrences. For this purpose, in this article, a new methodology was formulated which includes： （I） ver- tical identification of petroleum migration and accumulation fluid dynamic systems in the superposed basins; （2） analysis of the effect of large scale regional faults and fault combinations on the fluids exchange between the vertically identified different systems; （3） analysis of petroleum migration and accumulation in each vertically identified system, and establishment of appropriate geological model of petroleum migration and accumulation for each vertically identified system. Using this methodology, the satisfactory results obtained in the Lunnan Uplift of Tarim Basin and Ludong Uplift of Jungar Basin case studies are： （1） existence of different vertical fluid dynamic systems in western China＇s superposed basins which are very necessary for understanding the mechanism of petroleum migration and accumu- lation; （2） in deep system, long-distance lateral petroleum migration and accumulation mainly take place along the long time exposed unconformity with weathered, fractured or karst reservoir rocks; （3） regio- nal faults are the main conducts for fluids migration from deep system up to middle and/or upper sys- tems. As to middle and/or upper systems, regional faults play a role of ＂petroleum source＂. Small faults within middle and/or upper systems conduct petroleum to carrier beds with less impeding force; （4） petroleum migrated from deep system vertically up to middle and/or upper systems will migrate lat- erally in carrier beds of these systems and accumulate to form nools near or far from faults.展开更多
A Monolithic integrated phase locked-loop （PLL） with a low phase noise is proposed in this paper. Several techniques are utilized to improve the performance of the PLL which works at the milli- meter-wave band. The ...A Monolithic integrated phase locked-loop （PLL） with a low phase noise is proposed in this paper. Several techniques are utilized to improve the performance of the PLL which works at the milli- meter-wave band. The on-chip high-Q eoplanar waveguides （CPWs） are utilized in the resonant tank and the differential current amplifier with a resonator is used to realize the VCO. In the output buffer circuit, several stages of cascaded source-followers connect and differential amplifiers are adopted to improve the driving capability of the PLL＇ s output signals. An improved analog multiplier topology is also used in the PD circuit to improve the gain of the PD. The proposed PLL is realized with a 0.2p, m GaAs pseudomorphie high electron mobility transistor （PHEMT） process. At 10 kHz offset from the center frequency, the measured output phase noise of the PLL output is only -88.83dBc/Hz. The circuit exhibits a low root mean sauare （RMS） litter of 1.68Ds.展开更多
Based on the structure of Elman and Jordan neural networks, a new dynamic neural network is constructed. The network can remember the past state of the hidden layer and adjust the effect of the past signal to the curr...Based on the structure of Elman and Jordan neural networks, a new dynamic neural network is constructed. The network can remember the past state of the hidden layer and adjust the effect of the past signal to the current value in real-time. And in order to enhance the signal processing capabilities, the feedback of output layer nodes is increased. A hybrid learning algorithm based on genetic algorithm （GA） and error back propagation algorithm （BP） is used to adjust the weight values of the network, which can accelerate the rate of convergence and avoid getting into local optimum. Finally, the improved neural network is utilized to identify underwater vehicle （UV） ＇ s hydrodynamic model, and the simulation results show that the neural network based on hybrid learning algorithm can improve the learning rate of convergence and identification nrecision.展开更多
The co-translational targeting or insertion of secretory and membrane proteins into the endoplasmic reticulum （ER） is a key biological process mediated by the signal recognition particle （SRP）. In eukaryotes, the ...The co-translational targeting or insertion of secretory and membrane proteins into the endoplasmic reticulum （ER） is a key biological process mediated by the signal recognition particle （SRP）. In eukaryotes, the SRP68-SRP72 （SRP68/72） heterodimer plays an essen- tial role in protein translocation. However, structural information on the two largest SRP proteins, SRP68 and SRP72, is limited, espe- cially regarding their interaction. Herein, we report the first crystal structures of human apo-SRP72 and the SRP68/72 complex at 2.91A. and 1.7A resolution, respectively. The SRP68-binding domain of SRP72 contains four atypical tetratricopeptide repeats （TPR） and a flexible C-terminal cap. Apo-SRP72 exists mainly as dimers in solution. To bind to SRP68, the SRP72 homodimer disassociates, and the indispensable C-terminal cap undergoes a pronounced conformational change to assist formation of the SRP68/72 heterodi- mer. A 23-residue polypeptide of SRP68 is sufficient for tight binding to SRP72 through its unusually hydrophobic and extended sur- face. Structural, biophysical, and mutagenesis analyses revealed that cancer-associated mutations disrupt the SRP68-SRP72 interaction and their co-localization with ER in mammalian cells. The results highlight the essential role of the SRP68-SRP72 inter- action in SRP-mediated protein translocation and provide a structural basis for disease diagnosis, pathophysiology, and drug design.展开更多
基金provided by the National Basic Research Program of China (No. 2006CB20235)
文摘In western China, most petroliferous basins are superposed due to their multi-periodic tectonic evolution, and the mechanisms of petroleum migration and accumulation are so complex that much more sophis- ticated methodologies are necessary for depiction of these mechanisms and identification of petroleum occurrences. For this purpose, in this article, a new methodology was formulated which includes： （I） ver- tical identification of petroleum migration and accumulation fluid dynamic systems in the superposed basins; （2） analysis of the effect of large scale regional faults and fault combinations on the fluids exchange between the vertically identified different systems; （3） analysis of petroleum migration and accumulation in each vertically identified system, and establishment of appropriate geological model of petroleum migration and accumulation for each vertically identified system. Using this methodology, the satisfactory results obtained in the Lunnan Uplift of Tarim Basin and Ludong Uplift of Jungar Basin case studies are： （1） existence of different vertical fluid dynamic systems in western China＇s superposed basins which are very necessary for understanding the mechanism of petroleum migration and accumu- lation; （2） in deep system, long-distance lateral petroleum migration and accumulation mainly take place along the long time exposed unconformity with weathered, fractured or karst reservoir rocks; （3） regio- nal faults are the main conducts for fluids migration from deep system up to middle and/or upper sys- tems. As to middle and/or upper systems, regional faults play a role of ＂petroleum source＂. Small faults within middle and/or upper systems conduct petroleum to carrier beds with less impeding force; （4） petroleum migrated from deep system vertically up to middle and/or upper systems will migrate lat- erally in carrier beds of these systems and accumulate to form nools near or far from faults.
基金Supported by the National Natural Science Foundation of China （No. 61106024, 60901012, 60976029） , the National High Technology Research and Development Program of China （No. 2011AA010301 ）, and the Science and Technology Program of Southeast University （No. K J2010402 ）.
文摘A Monolithic integrated phase locked-loop （PLL） with a low phase noise is proposed in this paper. Several techniques are utilized to improve the performance of the PLL which works at the milli- meter-wave band. The on-chip high-Q eoplanar waveguides （CPWs） are utilized in the resonant tank and the differential current amplifier with a resonator is used to realize the VCO. In the output buffer circuit, several stages of cascaded source-followers connect and differential amplifiers are adopted to improve the driving capability of the PLL＇ s output signals. An improved analog multiplier topology is also used in the PD circuit to improve the gain of the PD. The proposed PLL is realized with a 0.2p, m GaAs pseudomorphie high electron mobility transistor （PHEMT） process. At 10 kHz offset from the center frequency, the measured output phase noise of the PLL output is only -88.83dBc/Hz. The circuit exhibits a low root mean sauare （RMS） litter of 1.68Ds.
基金Supported by the Postdoctoral Science Foundation of China（ No. 20100480964 ） , the Basic Research Foundation of Central University （ No. HEUCF100104） and the National Natural Science Foundation of China （No. 50909025/E091002）.
文摘Based on the structure of Elman and Jordan neural networks, a new dynamic neural network is constructed. The network can remember the past state of the hidden layer and adjust the effect of the past signal to the current value in real-time. And in order to enhance the signal processing capabilities, the feedback of output layer nodes is increased. A hybrid learning algorithm based on genetic algorithm （GA） and error back propagation algorithm （BP） is used to adjust the weight values of the network, which can accelerate the rate of convergence and avoid getting into local optimum. Finally, the improved neural network is utilized to identify underwater vehicle （UV） ＇ s hydrodynamic model, and the simulation results show that the neural network based on hybrid learning algorithm can improve the learning rate of convergence and identification nrecision.
文摘The co-translational targeting or insertion of secretory and membrane proteins into the endoplasmic reticulum （ER） is a key biological process mediated by the signal recognition particle （SRP）. In eukaryotes, the SRP68-SRP72 （SRP68/72） heterodimer plays an essen- tial role in protein translocation. However, structural information on the two largest SRP proteins, SRP68 and SRP72, is limited, espe- cially regarding their interaction. Herein, we report the first crystal structures of human apo-SRP72 and the SRP68/72 complex at 2.91A. and 1.7A resolution, respectively. The SRP68-binding domain of SRP72 contains four atypical tetratricopeptide repeats （TPR） and a flexible C-terminal cap. Apo-SRP72 exists mainly as dimers in solution. To bind to SRP68, the SRP72 homodimer disassociates, and the indispensable C-terminal cap undergoes a pronounced conformational change to assist formation of the SRP68/72 heterodi- mer. A 23-residue polypeptide of SRP68 is sufficient for tight binding to SRP72 through its unusually hydrophobic and extended sur- face. Structural, biophysical, and mutagenesis analyses revealed that cancer-associated mutations disrupt the SRP68-SRP72 interaction and their co-localization with ER in mammalian cells. The results highlight the essential role of the SRP68-SRP72 inter- action in SRP-mediated protein translocation and provide a structural basis for disease diagnosis, pathophysiology, and drug design.
