In order to determine the characteristics of noise source accurately, the noisedistribution at different frequencies was determined by taking the differences into accountbetween aerodynamic noises, mechanical noise, e...In order to determine the characteristics of noise source accurately, the noisedistribution at different frequencies was determined by taking the differences into accountbetween aerodynamic noises, mechanical noise, electrical noise in terms of in frequencyand intensity.Designed a least squares wavelet with high precision and special effects forstrong interference zone (multi-source noise), which is applicable to strong noise analysisproduced by underground mine, and obtained distribution of noise in different frequencyand achieves good results.According to the results of decomposition, the characteristicsof noise sources production can be more accurately determined, which lays a good foundationfor the follow-up focused and targeted noise control, and provides a new methodthat is greatly applicable for testing and analyzing noise control.展开更多
The decoherence process is analyzed for an open quantum system that is classically chaotic,with a classicallinear frequency entropy developed to measure the stability of classical motion,Investigation shows that the d...The decoherence process is analyzed for an open quantum system that is classically chaotic,with a classicallinear frequency entropy developed to measure the stability of classical motion,Investigation shows that the decoherencemeasured by the rate of quantum linear entropy production varies significantly with both the underlying classical orbitsand the classical linear frequency entropy.Such correspondence is also supported by the further investigation on theLoschmidt Echo.展开更多
A desiga of arbitrary waveform generator using NI PXI- 5412 module （an arbitrary waveform generator） was provided in this paper, based on virtual instrument technology and LabVIEW. The generator can produce standard...A desiga of arbitrary waveform generator using NI PXI- 5412 module （an arbitrary waveform generator） was provided in this paper, based on virtual instrument technology and LabVIEW. The generator can produce standard function waveforms, such as sine, triangle, square wave with adjustable amplitude and frequency. It can also produce arbitrary waveforms of different data files importing by Analog Waveform Geaemtor Software. A heart dectric wavefonn was set as an example of arbitrary waveform generation. It has practical value, because the standard functions and heart electric waveforms generated by the generator can be used in laboratories.展开更多
Water is an important factor affecting growth, yield and distribution of different species. Plant response to water deficit can be in the form of physiological disorders, such as reduction in transpiration or assimila...Water is an important factor affecting growth, yield and distribution of different species. Plant response to water deficit can be in the form of physiological disorders, such as reduction in transpiration or assimilating partitioning to root growth. Sustainable use of water has become a priority in agriculture and thus innovative irrigation management practices are critical. The study aimed at investigating how watering frequency and terminal water stress influence growth of Pelargonium sidoides, an important medicinal plant in Southern Africa. The trial was a randomized complete block design with three replicates, and treatment factors were watering frequency （everyday, twice and once a week） and terminal water stress （no watering four weeks before harvesting, no watering two weeks before harvesting and no terminal stress）. There was an interacting effect of watering frequency and terminal water stress on biomass and fresh root yield. More frequent watering resulted in significantly higher biomass and fresh root yield, compared to other treatments. Watering everyday with terminal or no terminal water stress resulted in higher fresh root yield, compared to other watering treatments with terminal water stress. Plant height and leaf area were significantly affected by watering frequency and terminal water stress, respectively. A significant drop in stomatal conductance of plants watered everyday was observed 240 d after treatment implementation, such that there was no significant difference across all the three watering frequency treatments. In conclusion, farmers can save on irrigation costs by reducing watering frequency, as there was no significant difference on dry root yield.展开更多
The increased production efficiency of heat treatable A1 alloys, as the result of applied electromagnetic field during continuous casting process was investigated. The applied frequency of the electromagnetic field （...The increased production efficiency of heat treatable A1 alloys, as the result of applied electromagnetic field during continuous casting process was investigated. The applied frequency of the electromagnetic field （EMF） during the AI alloys continuous casting was changing from 30 Hz to 50 Hz, while some castings were obtained without the EMF influence. The mechanical characterization of continuous casted AI alloys EN AW 2007 and En AW 2024 was done on testing machine Zwick/Roell Z 100. The microstructure of as-cast samples was examined, as well. When the frequency decreases （from 50 Hz to 30 Hz）, the grain size decreases as well, what is noticeable through the finer microstructure and its uniformity throughout the cross-section. These results have shown that low frequency electromagnetic field significantly influenced the microstructure and therefore the mechanical properties of as cast ingots. Thus, through improved castings quality, operation time and energy savings, the production efficiency was increased.展开更多
Thirteen-year satellite-derived data are used to investigate the temporal variability of net primary production （NPP） in the Oman upwelling zone and its potential forcing mechanisms. The NPP in the Oman upwelling zo...Thirteen-year satellite-derived data are used to investigate the temporal variability of net primary production （NPP） in the Oman upwelling zone and its potential forcing mechanisms. The NPP in the Oman upwelling zone is characterized by an abnormal decrease during E1 Nifio events. Such an NPP decrease may be related to E1 Nifio-driven anomalous summertime weak wind. During the summer following E1 Nifio, the anomalous northeasterly wind forced by southwest Indian Ocean warming weakens the southwest monsoon and warms the Arabian Sea. The abnormal wind weakens the coastal Ekman transport, offshore Ekman pumping and horizontal advection, resulting in reduced upward nutrient supply to the euphotic zone. A slightly declining trend in NPP after 2000 associated with a gradual decrease in surface monsoon winds is discussed.展开更多
An evaluation was performed on the influence of mowing height (2.5,5.0 or 7.5 cm) and mowing frequency (weekly or fortnightly) on levels of ergot alkaloids (ergine and ergonovine) formed in drunken horse grass,Achnath...An evaluation was performed on the influence of mowing height (2.5,5.0 or 7.5 cm) and mowing frequency (weekly or fortnightly) on levels of ergot alkaloids (ergine and ergonovine) formed in drunken horse grass,Achnatherum inebrians,grown under greenhouse conditions.Samples were taken monthly and alkaloids were extracted and analyzed by reverse-phase HPLC.Alkaloid levels increased more or less linearly with plant age over the first four months following establishment.Levels were higher in samples cut fortnightly compared to those cut weekly,and were higher when plants were cut at a mowing height of 7.5 cm vs.2.5 cm.In most cases,the highest alkaloid levels observed were almost three times those of the lowest.If plant protection applications are developed for the endophytic fungus,Neotyphodium gansuense,it will be necessary to be aware of the potential role of plant husbandry practices (e.g.,defoliation frequency and intensity) for reducing or enhancing levels of plant alkaloids.Similar husbandry factors may affect alkaloid levels in other Neotyphodium-grass associations,which would be interesting for further study.展开更多
基金Supported by the National Natural Science Fundation of China(50974061)the Natural Science Fundation of Hebei Province(E2009001420)
文摘In order to determine the characteristics of noise source accurately, the noisedistribution at different frequencies was determined by taking the differences into accountbetween aerodynamic noises, mechanical noise, electrical noise in terms of in frequencyand intensity.Designed a least squares wavelet with high precision and special effects forstrong interference zone (multi-source noise), which is applicable to strong noise analysisproduced by underground mine, and obtained distribution of noise in different frequencyand achieves good results.According to the results of decomposition, the characteristicsof noise sources production can be more accurately determined, which lays a good foundationfor the follow-up focused and targeted noise control, and provides a new methodthat is greatly applicable for testing and analyzing noise control.
基金Supported by National Natural Science Foundation of China under Grant Nos.10375042 and 10875087
文摘The decoherence process is analyzed for an open quantum system that is classically chaotic,with a classicallinear frequency entropy developed to measure the stability of classical motion,Investigation shows that the decoherencemeasured by the rate of quantum linear entropy production varies significantly with both the underlying classical orbitsand the classical linear frequency entropy.Such correspondence is also supported by the further investigation on theLoschmidt Echo.
基金supported by Research Project of "SUST Spring Bud"from Shandong University of Science and Technology(No.2008BWZ042)
文摘A desiga of arbitrary waveform generator using NI PXI- 5412 module （an arbitrary waveform generator） was provided in this paper, based on virtual instrument technology and LabVIEW. The generator can produce standard function waveforms, such as sine, triangle, square wave with adjustable amplitude and frequency. It can also produce arbitrary waveforms of different data files importing by Analog Waveform Geaemtor Software. A heart dectric wavefonn was set as an example of arbitrary waveform generation. It has practical value, because the standard functions and heart electric waveforms generated by the generator can be used in laboratories.
文摘Water is an important factor affecting growth, yield and distribution of different species. Plant response to water deficit can be in the form of physiological disorders, such as reduction in transpiration or assimilating partitioning to root growth. Sustainable use of water has become a priority in agriculture and thus innovative irrigation management practices are critical. The study aimed at investigating how watering frequency and terminal water stress influence growth of Pelargonium sidoides, an important medicinal plant in Southern Africa. The trial was a randomized complete block design with three replicates, and treatment factors were watering frequency （everyday, twice and once a week） and terminal water stress （no watering four weeks before harvesting, no watering two weeks before harvesting and no terminal stress）. There was an interacting effect of watering frequency and terminal water stress on biomass and fresh root yield. More frequent watering resulted in significantly higher biomass and fresh root yield, compared to other treatments. Watering everyday with terminal or no terminal water stress resulted in higher fresh root yield, compared to other watering treatments with terminal water stress. Plant height and leaf area were significantly affected by watering frequency and terminal water stress, respectively. A significant drop in stomatal conductance of plants watered everyday was observed 240 d after treatment implementation, such that there was no significant difference across all the three watering frequency treatments. In conclusion, farmers can save on irrigation costs by reducing watering frequency, as there was no significant difference on dry root yield.
文摘The increased production efficiency of heat treatable A1 alloys, as the result of applied electromagnetic field during continuous casting process was investigated. The applied frequency of the electromagnetic field （EMF） during the AI alloys continuous casting was changing from 30 Hz to 50 Hz, while some castings were obtained without the EMF influence. The mechanical characterization of continuous casted AI alloys EN AW 2007 and En AW 2024 was done on testing machine Zwick/Roell Z 100. The microstructure of as-cast samples was examined, as well. When the frequency decreases （from 50 Hz to 30 Hz）, the grain size decreases as well, what is noticeable through the finer microstructure and its uniformity throughout the cross-section. These results have shown that low frequency electromagnetic field significantly influenced the microstructure and therefore the mechanical properties of as cast ingots. Thus, through improved castings quality, operation time and energy savings, the production efficiency was increased.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences (Nos. KZCX2-YW-Q11-02, LYQY200807)the National Natural Science Foundation of China (Nos. 40876093, 41176162)
文摘Thirteen-year satellite-derived data are used to investigate the temporal variability of net primary production （NPP） in the Oman upwelling zone and its potential forcing mechanisms. The NPP in the Oman upwelling zone is characterized by an abnormal decrease during E1 Nifio events. Such an NPP decrease may be related to E1 Nifio-driven anomalous summertime weak wind. During the summer following E1 Nifio, the anomalous northeasterly wind forced by southwest Indian Ocean warming weakens the southwest monsoon and warms the Arabian Sea. The abnormal wind weakens the coastal Ekman transport, offshore Ekman pumping and horizontal advection, resulting in reduced upward nutrient supply to the euphotic zone. A slightly declining trend in NPP after 2000 associated with a gradual decrease in surface monsoon winds is discussed.
基金supported by the National Basic Research Program of China (Grant No. 2007CB108902)the National Natural Science Foundation of China (Grant No. 30771531)+1 种基金Program for New Century Excellent Talents in University (Grant No. NCET-08-0256)the Fundamental Research Funds for the Central Universities (Grant No. LZUJBKY-2009-156)
文摘An evaluation was performed on the influence of mowing height (2.5,5.0 or 7.5 cm) and mowing frequency (weekly or fortnightly) on levels of ergot alkaloids (ergine and ergonovine) formed in drunken horse grass,Achnatherum inebrians,grown under greenhouse conditions.Samples were taken monthly and alkaloids were extracted and analyzed by reverse-phase HPLC.Alkaloid levels increased more or less linearly with plant age over the first four months following establishment.Levels were higher in samples cut fortnightly compared to those cut weekly,and were higher when plants were cut at a mowing height of 7.5 cm vs.2.5 cm.In most cases,the highest alkaloid levels observed were almost three times those of the lowest.If plant protection applications are developed for the endophytic fungus,Neotyphodium gansuense,it will be necessary to be aware of the potential role of plant husbandry practices (e.g.,defoliation frequency and intensity) for reducing or enhancing levels of plant alkaloids.Similar husbandry factors may affect alkaloid levels in other Neotyphodium-grass associations,which would be interesting for further study.
