A static flux chamber method was applied to study natural emissions of methane into the atmosphere in the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China. Using an online method, which couples a gas ch...A static flux chamber method was applied to study natural emissions of methane into the atmosphere in the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China. Using an online method, which couples a gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/C/MS) together, the 13C/12C ratios of methane in the flux chambers were measured. The results demonstrated that methane gases were liable to migrate from deep oil/gas reservoir to the surface through microseepage and pervasion, and that a part of the migrated methane that remained unoxidized could emit into the atmosphere. Methane emission rates varied less in the oil/gas field because the whole region was homogeneous in geology and geography, with a standard deviation of less than 0.02 mg/(m2·h). These were the differences in methane emission flux in the day and at night in the oil/gas field. The maximum methane emission flux reached 0.15 mg/(m2·h) at 5:00-6:00 early in the morning, and then decreased gradually. The minimum was shown 0.10 mg/(m2·h) at 17:00-18:00 in the afternoon, and then increased gradually. The daily methane released flux of the study area was 2.89 mg/(m2·d), with a standard deviation of 0.43 mg/(m2·d), using the average methane flux of every hour in a day for all chambers. δ13C of methane increased with the increase of methane concentration in the flux chambers, further indicating that the pyrogenetic origin of methane was come from deep oil/gas reservoirs.展开更多
Two signature systems based on smart cards and fingerprint features are proposed. In one signature system, the cryptographic key is stored in the smart card and is only accessible when the signer's extracted finge...Two signature systems based on smart cards and fingerprint features are proposed. In one signature system, the cryptographic key is stored in the smart card and is only accessible when the signer's extracted fingerprint features match his stored template. To resist being tampered on public channel, the user's message and the signed message are encrypted by the signer's public key and the user's public key, respectively. In the other signature system, the keys are generated by combining the signer's fingerprint features, check bits, and a rememberable key, and there are no matching process and keys stored on the smart card. Additionally, there is generally more than one public key in this system, that is, there exist some pseudo public keys except a real one.展开更多
To suppress noise amplitude modulation jamming in a single-antenna radar system,a new method based on weighted-matching pursuit(WMP) algorithm is proposed,which can achieve underdetermined blind sources separation of ...To suppress noise amplitude modulation jamming in a single-antenna radar system,a new method based on weighted-matching pursuit(WMP) algorithm is proposed,which can achieve underdetermined blind sources separation of the jamming and the target echo from the jammed mixture in the single channel of the receiver.Firstly, the presented method utilizes a prior information about the differences between the jamming component and the radar transmitted signal to construct two signal-adapted sub-dictionaries and to determine the weights.Then the WMP algorithm is applied to remove the jamming component from the mixture.Experimental results verify the validity of the presented method.By comparison of the pulse compression performance,the simulation results shows that the presented method is superior to the method of frequency domain cancellation(FDC) when the jamming-to-signal ratio(JSR) is lower than 15 dB.展开更多
. The D-η-proper prequasi-invexity of vector-valued functions is characterized by means of (weak) nearly convexity and density of sets.Under weaker assumptions,some equivalent conditions for D-η-proper prequasi-inve.... The D-η-proper prequasi-invexity of vector-valued functions is characterized by means of (weak) nearly convexity and density of sets.Under weaker assumptions,some equivalent conditions for D-η-proper prequasi-invexity are derived.展开更多
The eigenvector of a module with six adjacent module's state was constructed according to self-reconfigurable robot M-Cubes and the configuration of system was expressed with the eigenvectors of all modules.Accord...The eigenvector of a module with six adjacent module's state was constructed according to self-reconfigurable robot M-Cubes and the configuration of system was expressed with the eigenvectors of all modules.According to the configuration and motion characteristics of the modules,a 3-dimension motion rule set was provided.The rule sets of each module was run according to eigenvector of the module after the motion direction of system decided and motion rules were selected.At last,the rapid and effective motion and metamorphosis were realized in system.The rule sets are operated on three systems and the distributed motion of system is fully realized.The result of simulation shows that the 3-dimension motion rule sets has perfect applicability and extensibility.The motion steps and communication load of the modules increase with the module number in linear.展开更多
Yang et al gave some criteria of prequasi invex functions,semistrictly prequasi invex functions and strictly prequasi invex functions in 2001,under a certain set of conditions.In this note,some of these conditions can...Yang et al gave some criteria of prequasi invex functions,semistrictly prequasi invex functions and strictly prequasi invex functions in 2001,under a certain set of conditions.In this note,some of these conditions can be weakened to get the same results,and another simplified proof for a criterion of prequasi invex functions established under the condition of lower semicontinuity is given.展开更多
基金the National Natural Sci-ence Foundation of China (No. 40273034)the Science Foundation of Hangzhou Dianzi University
文摘A static flux chamber method was applied to study natural emissions of methane into the atmosphere in the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China. Using an online method, which couples a gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/C/MS) together, the 13C/12C ratios of methane in the flux chambers were measured. The results demonstrated that methane gases were liable to migrate from deep oil/gas reservoir to the surface through microseepage and pervasion, and that a part of the migrated methane that remained unoxidized could emit into the atmosphere. Methane emission rates varied less in the oil/gas field because the whole region was homogeneous in geology and geography, with a standard deviation of less than 0.02 mg/(m2·h). These were the differences in methane emission flux in the day and at night in the oil/gas field. The maximum methane emission flux reached 0.15 mg/(m2·h) at 5:00-6:00 early in the morning, and then decreased gradually. The minimum was shown 0.10 mg/(m2·h) at 17:00-18:00 in the afternoon, and then increased gradually. The daily methane released flux of the study area was 2.89 mg/(m2·d), with a standard deviation of 0.43 mg/(m2·d), using the average methane flux of every hour in a day for all chambers. δ13C of methane increased with the increase of methane concentration in the flux chambers, further indicating that the pyrogenetic origin of methane was come from deep oil/gas reservoirs.
基金This project was supported by the National Science Foundation of China (60763009)China Postdoctoral Science Foundation (2005038041)Hainan Natural Science Foundation (80528).
文摘Two signature systems based on smart cards and fingerprint features are proposed. In one signature system, the cryptographic key is stored in the smart card and is only accessible when the signer's extracted fingerprint features match his stored template. To resist being tampered on public channel, the user's message and the signed message are encrypted by the signer's public key and the user's public key, respectively. In the other signature system, the keys are generated by combining the signer's fingerprint features, check bits, and a rememberable key, and there are no matching process and keys stored on the smart card. Additionally, there is generally more than one public key in this system, that is, there exist some pseudo public keys except a real one.
文摘To suppress noise amplitude modulation jamming in a single-antenna radar system,a new method based on weighted-matching pursuit(WMP) algorithm is proposed,which can achieve underdetermined blind sources separation of the jamming and the target echo from the jammed mixture in the single channel of the receiver.Firstly, the presented method utilizes a prior information about the differences between the jamming component and the radar transmitted signal to construct two signal-adapted sub-dictionaries and to determine the weights.Then the WMP algorithm is applied to remove the jamming component from the mixture.Experimental results verify the validity of the presented method.By comparison of the pulse compression performance,the simulation results shows that the presented method is superior to the method of frequency domain cancellation(FDC) when the jamming-to-signal ratio(JSR) is lower than 15 dB.
文摘. The D-η-proper prequasi-invexity of vector-valued functions is characterized by means of (weak) nearly convexity and density of sets.Under weaker assumptions,some equivalent conditions for D-η-proper prequasi-invexity are derived.
基金The National Natural Science Foundation of China(No.50305021)
文摘The eigenvector of a module with six adjacent module's state was constructed according to self-reconfigurable robot M-Cubes and the configuration of system was expressed with the eigenvectors of all modules.According to the configuration and motion characteristics of the modules,a 3-dimension motion rule set was provided.The rule sets of each module was run according to eigenvector of the module after the motion direction of system decided and motion rules were selected.At last,the rapid and effective motion and metamorphosis were realized in system.The rule sets are operated on three systems and the distributed motion of system is fully realized.The result of simulation shows that the 3-dimension motion rule sets has perfect applicability and extensibility.The motion steps and communication load of the modules increase with the module number in linear.
基金Supported by the Zhejiang Province Natural Science Foundation( 60 2 0 95 )
文摘Yang et al gave some criteria of prequasi invex functions,semistrictly prequasi invex functions and strictly prequasi invex functions in 2001,under a certain set of conditions.In this note,some of these conditions can be weakened to get the same results,and another simplified proof for a criterion of prequasi invex functions established under the condition of lower semicontinuity is given.
